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  • 1.
    Abreu, Clare I.
    et al.
    MIT, USA;Stanford Univ, USA.
    Dal Bello, Martina
    MIT, USA.
    Bunse, Carina
    University of Gothenburg, Sweden.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gore, Jeff
    MIT, USA.
    Warmer temperatures favor slower-growing bacteria in natural marine communities2023In: Science Advances, E-ISSN 2375-2548, Vol. 9, no 19, article id 26eade8352Article in journal (Refereed)
    Abstract [en]

    Earth's life-sustaining oceans harbor diverse bacterial communities that display varying composition across time and space. While particular patterns of variation have been linked to a range of factors, unifying rules are lacking, preventing the prediction of future changes. Here, analyzing the distribution of fast- and slowgrowing bacteria in ocean datasets spanning seasons, latitude, and depth, we show that higher seawater temperatures universally favor slower-growing taxa, in agreement with theoretical predictions of how temperaturedependent growth rates differentially modulate the impact of mortality on species abundances. Changes in bacterial community structure promoted by temperature are independent of variations in nutrients along spatial and temporal gradients. Our results help explain why slow growers dominate at the ocean surface, during summer, and near the tropics and provide a framework to understand how bacterial communities will change in a warmer world.

  • 2.
    Ackerfors, Viktoria
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Vilken inställning har Länsstyrelserna till naturvårdsbränningar i områden med fornlämningar och övriga kulturhistoriska lämningar?2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Skogsbränderna har en stor betydelse för den biologiska mångfalden. Det brandpåverkade landskapet och dess dynamik skapar viktiga substrat och livsmiljöer för många pyrofila arter. På grund av att skogsbränderna har minskat i antal sedan 1800-talet, har kontrollerade naturvårdsbränningar utförts som ett komplement för dessa sedan 1980-talet. De kontrollerade naturvårdsbränningarna skapar de miljöer och substrat som många arter är beroende av. Eftersom tidigare mänsklig verksamhet satt prägel på skogarna återfinns idag ett stort antal fornlämningar och övriga kulturhistoriska lämningar i skogsmarkerna. Det är en utmaning att utföra naturvårdsbränningarna så att dessa lämningar inte skadas. Det råder också en brist på tydliga riktlinjer om hur Länsstyrelserna ska förhålla sig till naturvårdsbränningar i områden med lämningar. Denna studies syfte var att undersöka vilken inställning Länsstyrelserna har till naturvårdsbränningar i områden med fornlämningar eller övriga kulturhistoriska lämningar.

    Nyckelord: Naturvårdsbränningar, fornlämningar, övriga kulturhistoriska lämningar, Länsstyrelsen

    Keyword: Prescribed burnings, ancient remains, other cultural-historical remains, County Administrative Boards

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  • 3.
    Adolfsson, Oscar
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Consequences on population dynamics following regained connectivity in pike (Esox lucius) spawning location2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Distributional movements of subpopulations may act as a buffer to prevent the loss of a species in a certain area. However, within subpopulations adaptations may evolve that makes the inhabitants of a certain habitat to better cope with prevailing environmental conditions. If such traits are related to reproduction, they may reduce the opportunity of gene exchange between other subpopulations. Also, a lack of adaptations to a specific habitat may be what prevents a group of individuals, arriving from an adjacent habitat, to successfully colonize an area where a previous subpopulation has been lost.This is the report from a field study conducted in the wetland Lake Långsjön, that in 2018 was restored in order to promote the recruitment of anadromous pike (Esox lucius) to the Baltic Sea. Commonly, wetlands that are restored to promote anadromous pike recruitment, are constructed so that they enable spawning migration from the sea towards the wetland and juvenile emigration towards the sea only. In that sense Lake Långsjön is different, from other wetlands restored for the same purpose, due to that it is connected to both the Baltic Sea and an upstream located freshwater lake. By quantifying the migration of pike (spawners and juveniles) in both directions I explore the consequences that the regained connectivity between the Lake Långsjön and the coast may have on the population dynamics within this wetland; (i) whether it is potentially influenced by allowing mixture between pike with different migratory strategies for spawning (anadromous and potamodromous), (ii) what drivers there are of pike fry emigration and how they may influence the pike fry emigration route and (iii) whether or not the pike of potamodromous origin, resident in the upstream located lake, may work as a source, providing the Baltic Sea with pike juveniles. Pike spawners arriving in the wetland were caught in traps between March - April. Pike fry were caught withing the wetland with fyke nets and by netting. Emigrating pike fry were caught in fyke nets. Findings suggest that spawning migration patterns do not differ between anadromous and potamodromous pike. However, the spawners arriving from the Baltic Sea I suggested are to be composed by offspring of potamodromous origin, possibly hatched during the previous season, and that they as juveniles swam downstream. This, in turn, indicates that the potamodromous stock can help establish an anadromous stock in the Baltic Sea. Still, due to the observation of pike fry displaying an emigration behaviour upstream, origin is identified as a factor that may influence the pike fry emigration route. Also, this emigration pattern seems to indicate a heritable trait that has not been described before among pike, that of downstream spawning. The restoration of the wetland and the regained connectivity is key, both for the ability to restock the Baltic Sea with pike juveniles but also to ensure the conservation of a fascinating stock of pike exhibiting a unique spawning strategy

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  • 4.
    Agostinelli, Marta
    et al.
    Swedish University of Agricultural Sciences, Sweden.
    Cleary, Michelle
    Swedish University of Agricultural Sciences, Sweden.
    Martín, Juan A
    Technical University of Madrid, Spain.
    Albrectsen, Benedicte R
    Umeå University, Sweden.
    Witzell, Johanna
    Swedish University of Agricultural Sciences, Sweden.
    Pedunculate Oaks (Quercus robur L.) Differing in Vitality as Reservoirs for Fungal Biodiversity2018In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 9, article id 1758Article in journal (Refereed)
    Abstract [en]

    Ecological significance of trees growing in urban and peri-urban settings is likely to increase in future land-use regimes, calling for better understanding of their role as potential reservoirs or stepping stones for associated biodiversity. We studied the diversity of fungal endophytes in woody tissues of asymptomatic even aged pedunculate oak trees, growing as amenity trees in a peri-urban setting. The trees were classified into three groups according to their phenotypic vitality (high, medium, and low). Endophytes were cultured on potato dextrose media from surface sterilized twigs and DNA sequencing was performed to reveal the taxonomic identity of the morphotypes. In xylem tissues, the frequency and diversity of endophytes was highest in oak trees showing reduced vitality. This difference was not found for bark samples, in which the endophyte infections were more frequent and communities more diverse than in xylem. In general, most taxa were shared across the samples with few morphotypes being recovered in unique samples. Leaf phenolic profiles were found to accurately classify the trees according to their phenotypic vitality. Our results confirm that xylem is more selective substrate for endophytes than bark and that endophyte assemblages in xylem are correlated to the degree of host vitality. Thus, high vitality of trees may be associated with reduced habitat quality to wood-associated endophytes.

  • 5.
    Aguilera, Anabella
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Alegria Zufia, Javier
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bas Conn, Laura
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gurlit, Leandra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Śliwińska‐Wilczewska, Sylwia
    Mount Allison University, Canada;University of Gdansk, Poland.
    Budzałek, Gracjana
    University of Gdansk, Poland.
    Lundin, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Halmstad University, Sweden.
    Farnelid, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Ecophysiological analysis reveals distinct environmental preferences in closely related Baltic Sea picocyanobacteria2023In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 25, no 9, p. 1674-1695Article in journal (Refereed)
    Abstract [en]

    Cluster 5 picocyanobacteria significantly contribute to primary productivity in aquatic ecosystems. Estuarine populations are highly diverse and consist of many co-occurring strains, but their physiology remains largely understudied. In this study, we characterized 17 novel estuarine picocyanobacterial strains. Phylogenetic analysis of the 16S rRNA and pigment genes (cpcBandcpeBA) uncovered multiple estuarine and freshwater-related clusters and pigment types. Assays with five representative strains (three phycocyanin rich and two phycoerythrin rich) under temperature (10–30°C), light(10–190 μmol  photons  m-2s-1), and salinity (2–14  PSU) gradients revealed distinct growth optima and tolerance, indicating that genetic variability was accompanied by physiological diversity. Adaptability to environmental conditions was associated with differential pigment content and photosynthetic performance. Amplicon sequence variants at a coastal and an offshore station linked population dynamics with phylogenetic clusters, supporting that strains isolated in this study represent key ecotypes within the Baltic Sea picocyanobacterial community. The functional diversity found within strains with the same pigment type suggests that understanding estuarine picocyanobacterial ecology requires analysis beyond the phycocyanin and phycoerythrin divide. This new knowledge of the environmental preferences in estuarine picocyanobacteria is important for understanding and evaluating productivity in current and future ecosystems.

  • 6.
    Aguilera, Anabella
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Almanza, Viviana
    Univ Concepcion, Chile.
    Haakonsson, Signe
    Univ Republica, Uruguay.
    Palacio, Hilda
    Univ CES, Colombia.
    Rodas, Gilberto A. Benitez
    Univ Nacl Asuncion, Paraguay.
    Barros, Mario U. G.
    Univ Fed Ceara, Brazil;Water Resources Management Co Ceara, Brazil.
    Capelo-Neto, Jose
    Univ Fed Ceara, Brazil.
    Urrutia, Roberto
    Univ Concepcion, Chile.
    Aubriot, Luis
    Univ Republica, Uruguay.
    Bonilla, Sylvia
    Univ Republica, Uruguay.
    Cyanobacterial bloom monitoring and assessment in Latin America2023In: Harmful Algae, ISSN 1568-9883, E-ISSN 1878-1470, Vol. 125, article id 102429Article in journal (Refereed)
    Abstract [en]

    Cyanobacterial blooms have serious adverse effects on human and environmental health. In Latin America, one of the main world's freshwater reserves, information on this phenomenon remains sparse. To assess the current situation, we gathered reports of cyanobacterial blooms and associated cyanotoxins in freshwater bodies from South America and the Caribbean (Latitude 22 degrees N to 45 degrees S) and compiled the regulation and monitoring procedures implemented in each country. As the operational definition of what is a cyanobacterial bloom remains controversial, we also analyzed the criteria used to determine the phenomena in the region. From 2000 to 2019, blooms were reported in 295 water bodies distributed in 14 countries, including shallow and deep lakes, reservoirs, and rivers. Cyanotoxins were found in nine countries and high concentrations of microcystins were reported in all types of water bodies. Blooms were defined according to different, and sometimes arbitrary criteria including qualitative (changes in water color, scum presence), quantitative (abundance), or both. We found 13 different cell abundance thresholds defining bloom events, from 2 x 10(3) to 1 x 10(7) cells mL(-1). The use of different criteria hampers the estimation of bloom occurrence, and consequently the associated risks and economic impacts. The large differences between countries in terms of number of studies, monitoring efforts, public access to the data and regulations regarding cyanobacteria and cyanotoxins highlights the need to rethink cyanobacterial bloom monitoring, seeking common criteria. General policies leading to solid frameworks based on defined criteria are needed to improve the assessment of cyanobacterial blooms in Latin America. This review represents a starting point toward common approaches for cyanobacterial monitoring and risk assessment, needed to improve regional environmental policies.

  • 7.
    Aguirre-Gutierrez, Jesus
    et al.
    Naturalis Biodivers Ctr, Netherlands;Univ Oxford, UK;Univ Amsterdam, Netherlands.
    WallisDeVries, Michiel F.
    De Vlinderstichting, Netherlands;Wageningen Univ, Netherlands.
    Marshall, Leon
    Naturalis Biodivers Ctr, Netherlands;Univ Namur, Belgium.
    van't Zelfde, Maarten
    Naturalis Biodivers Ctr, Netherlands;Leiden Univ, Netherlands.
    Villalobos-Arambula, Alma R.
    Univ Guadalajara, Mexico.
    Boekelo, Bastiaen
    Wageningen Univ & Res, Netherlands.
    Bartholomeus, Harm
    Wageningen Univ & Res, Netherlands.
    Franzén, Markus
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. UFZ, Helmholtz Ctr Environm Res, Germany.
    Biesmeijer, Jacobus C.
    Naturalis Biodivers Ctr, Netherlands;Leiden Univ, Netherlands.
    Butterflies show different functional and species diversity in relationship to vegetation structure and land use2017In: Global Ecology and Biogeography, ISSN 1466-822X, E-ISSN 1466-8238, Vol. 26, no 10, p. 1126-1137Article in journal (Refereed)
    Abstract [en]

    AimBiodiversity is rapidly disappearing at local and global scales also affecting the functional diversity of ecosystems. We aimed to assess whether functional diversity was correlated with species diversity and whether both were affected by similar land use and vegetation structure drivers. Better understanding of these relationships will allow us to improve our predictions regarding the effects of future changes in land use on ecosystem functions and services. LocationThe Netherlands. MethodsWe compiled a dataset of c.3 million observations of 66 out of 106 known Dutch butterfly species collected across 6,075 sampling locations during a period of 7 years, together with very high-resolution maps of land use and countrywide vegetation structure data. Using a mixed-effects modelling framework, we investigated the relationship between functional and species diversity and their main land use and vegetation structure drivers. ResultsWe found that high species diversity does not translate into high functional diversity, as shown by their different spatial distribution patterns in the landscape. Functional and species diversity are mainly driven by different sets of structural and land use parameters (especially average vegetation height, amount of vegetation between 0.5 and 2m, natural grassland, sandy soils vegetation, marsh vegetation and urban areas). We showed that it is a combination of both vegetation structural characteristics and land use variables that defines functional and species diversity. Main conclusionsFunctional diversity and species diversity of butterflies are not consistently correlated and must therefore be treated separately. High functional diversity levels occurred even in areas with low species diversity. Thus, conservation actions may differ depending on whether the focus is on conservation of high functional diversity or high species diversity. A more integrative analysis of biodiversity at both species and trait levels is needed to infer the full effects of environmental change on ecosystem functioning.

  • 8.
    Ahlstrom, Christina A.
    et al.
    US Geol Survey, USA.
    van Toor, Mariëlle L.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Woksepp, Hanna
    Kalmar County Hospital, Sweden.
    Chandler, Jeffrey C.
    USDA APHIS WS, USA.
    Reed, John A.
    US Geol Survey, USA.
    Reeves, Andrew B.
    US Geol Survey, USA.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Franklin, Alan B.
    USDA APHIS WS, USA.
    Douglas, David C.
    US Geol Survey, USA.
    Bonnedahl, Jonas
    Linköping University, Sweden;Region Kalmar county, Sweden.
    Ramey, Andrew M.
    US Geol Survey, USA.
    Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls2021In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 764, p. 1-10, article id 144551Article, review/survey (Refereed)
    Abstract [en]

    Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement patterns, and a novel modeling approach to combine information from these diverse data streams to investigate the acquisition and long-distance dispersal of antimicrobial resistant bacteria by landfill-foraging gulls. Our results provide evidence that gulls acquire antimicrobial resistant bacteria from anthropogenic sources, which they may subsequently disperse across and between continents via migratory movements. Furthermore, we introduce a flexible modeling framework to estimate the relative dispersal risk of antimicrobial resistant bacteria in western North America and adjacent areas within East Asia, which may be adapted to provide information on the risk of dissemination of other organisms and pathogens maintained by wildlife through space and time. Published by Elsevier B.V.

  • 9.
    Akram, Neelam
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Palovaara, Joakim
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Forsberg, Jeremy
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindh, Markus V.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Milton, Debra L.
    Luo, Haiwei
    Gonzalez, Jose M.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Regulation of proteorhodopsin gene expression by nutrient limitation in the marine bacterium Vibrio sp AND42013In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 15, no 5, p. 1400-1415Article in journal (Refereed)
    Abstract [en]

    Proteorhodopsin (PR), a ubiquitous membrane photoprotein in marine environments, acts as a light-driven proton pump and can provide energy for bacterial cellular metabolism. However, knowledge of factors that regulate PR gene expression in different bacteria remains strongly limited. Here, experiments with Vibrio sp. AND4 showed that PR phototrophy promoted survival only in cells from stationary phase and not in actively growing cells. PR gene expression was tightly regulated, with very low values in exponential phase, a pronounced peak at the exponential/stationary phase intersection, and a marked decline in stationary phase. Thus, PR gene expression at the entry into stationary phase preceded, and could therefore largely explain, the stationary phase light-induced survival response in AND4. Further experiments revealed nutrient limitation, not light exposure, regulated this differential PR expression. Screening of available marine vibrios showed that the PR gene, and thus the potential for PR phototrophy, is found in at least three different clusters in the genus Vibrio. In an ecological context, our findings suggest that some PR-containing bacteria adapted to the exploitation of nutrient-rich micro-environments rely on a phase of relatively slowly declining resources to mount a cellular response preparing them for adverse conditions dispersed in the water column.

  • 10.
    Alam, A. B. M. Sarowar
    et al.
    IUCN Bangladesh, Dhaka, Bangladesh..
    Ahmed, Sakib
    IUCN Bangladesh, Bangladesh.
    Azmiri, Kazi Zenifar
    IUCN Bangladesh, Bangladesh.
    Amin, Raquibul
    IUCN Bangladesh, Bangladesh.
    van Toor, Mariëlle L.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Datta, Ashis Kumar
    Jahangirnagar Univ, Bangladesh.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Ul Haque, Enam
    Bangladesh Bird Club, Bangladesh.
    Chowdhury, Sayam U.
    Univ Cambridge, UK.
    Population trends and effects of local environmental factors on waterbirds at Tanguar Haor freshwater wetland complex in northeast Bangladesh2023In: Avian Conservation and Ecology - Écologie et conservation des oiseaux, ISSN 1712-6568, E-ISSN 1712-6568, Vol. 18, no 1, article id 18Article in journal (Refereed)
    Abstract [en]

    Analysis of long-term datasets on bird populations can be used to answer ecological and management questions that are useful for conservation. Tanguar Haor (9500 ha) is one of the major freshwater wetlands in Bangladesh and supports a large number of migratory and resident waterbirds. Because of its unique ecological and economic values, it is arguably the most notable wetland in the floodplains of northeast Bangladesh and in the region. This Ramsar site supports globally important populations of threatened waterbirds, such as the Baer's Pochard Aythya baeri, Common Pochard Aythya ferina, Falcated Duck Mareca falcata, Ferruginous Duck Aythya nyroca, Oriental Darter Anhinga melanogaster, and Black-tailed Godwit Limosa limosa. Considering the international significance of this site, knowledge gaps on waterbird population trends, and key ecological factors, we conducted waterbird census between 2008 and 2021 to identify priority sites for conservation, population trends of resident and migratory waterbirds, and environmental factors that influence their abundances. We recorded a total of 69 species of waterbirds (maximum count of 166,788 individuals in 2013) and assessed population trends of 47 species. Of these, peak counts of 15 species exceeded the 1% threshold of their Asian-Australian Flyway population estimates. Most species (59%) showed a declining trend, including the critically endangered Baer's Pochard and the vulnerable Common Pochard, and 16 species (41%) showed an increasing trend. Based on the abundance and species diversity, we have identified Chotainna beel and Lechuamara beel as conservation priority sites within the Haor complex and discuss key threats to these areas. We also offer evidence that adjusting water-level management to annual rainfall patterns could be a useful intervention for waterbird management. Involving local communities in conservation efforts by creating bird sanctuaries within the Haor complex will strengthen waterbird conservation in the country and along the East Asian-Australian Flyway.

  • 11.
    Alatalo, Rauno V.
    et al.
    University of Jyväskylä, Finland.
    Eriksson, Dag
    Uppsala University, Sweden.
    Gustafsson, Lars
    Uppsala University, Sweden.
    Larsson, Kjell
    Uppsala University, Sweden.
    Exploitation competition influences the use of foraging sites by tits: Experimental evidence1987In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 68, no 2, p. 284-290Article in journal (Refereed)
    Abstract [en]

    In coniferous forests of central Sweden, tits (Paridae) and the Goldcrest, Regulus regulus, exploit nonrenewable resources in their group territories during winter. The smaller and socially subordinate species, the Goldcrest and the Coal Tit, Parus ater, forage on the outermost tree parts, while the larger and dominant Willow Tit, Parus montanus, and Crested Tit, Parus cristatus, forage on the inner tree parts. We removed Coal Tits and Goldcrests in three flocks in early winter to see if their absence would cause changes in the foraging patterns of the two dominant species. In late winter, Crested Tits foraged farther outward on branches of spruce in experimental flocks than they did in the control flocks. In spruce, Willow Tits foraged nearer the trunk than Crested Tits, and they did not respond to the experiment. In pine, Willow Tits, however, did move from branches to twigs in the absence of Coal Tits and Goldcrests. The experiment indicates that exploitation competition directly based on food depletion, without any interference, may influence the use of foraging sites by tits in coniferous forests.

  • 12. Alder, V A
    et al.
    Cuzin-Roudy, J
    Fransz, G
    Granéli, Edna
    Department of Marine Ecology, University of Lund .
    Larsen, J
    Rabbani, M M
    Thomsen, H
    Macro- and micrograzing effects on phytoplankton communities1989In: The expedition Antarktis VII/3 (EPOS LEG 2) of RV "Polarstern" in 1988/89 / [ed] I. Hempel, P.H. Schalk and V. Smetacek, Bremerhaven: Alfred- Wegener-Institut für Polar Meeresforschung , 1989, p. 123-130Chapter in book (Other academic)
  • 13.
    Alegria Zufia, Javier
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Farnelid, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Linnaeus University, Linnaeus Knowledge Environments, Water.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Linnaeus University, Linnaeus Knowledge Environments, Water. Halmstad University, Sweden.
    Seasonality of Coastal Picophytoplankton Growth, Nutrient Limitation, and Biomass Contribution2021In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 12, article id 786590Article in journal (Refereed)
    Abstract [en]

    Picophytoplankton in the Baltic Sea includes the simplest unicellular cyanoprokaryotes (Synechococcus/Cyanobium) and photosynthetic picoeukaryotes (PPE). Picophytoplankton are thought to be a key component of the phytoplankton community, but their seasonal dynamics and relationships with nutrients and temperature are largely unknown. We monitored pico- and larger phytoplankton at a coastal site in Kalmar Sound (K-Station) weekly during 2018. Among the cyanoprokaryotes, phycoerythrin-rich picocyanobacteria (PE-rich) dominated in spring and summer while phycocyanin-rich picocyanobacteria (PC-rich) dominated during autumn. PE-rich and PC-rich abundances peaked during summer (1.1 x 10(5) and 2.0 x 10(5) cells mL(-1)) while PPE reached highest abundances in spring (1.1 x 10(5) cells mL(-1)). PPE was the main contributor to the total phytoplankton biomass (up to 73%). To assess nutrient limitation, bioassays with combinations of nitrogen (NO3 or NH4) and phosphorus additions were performed. PE-rich and PC-rich growth was mainly limited by nitrogen, with a preference for NH4 at >15 degrees C. The three groups had distinct seasonal dynamics and different temperature ranges: 10 degrees C and 17-19 degrees C for PE-rich, 13-16 degrees C for PC-rich and 11-15 degrees C for PPE. We conclude that picophytoplankton contribute significantly to the carbon cycle in the coastal Baltic Sea and underscore the importance of investigating populations to assess the consequences of the combination of high temperature and NH4 in a future climate.

  • 14.
    Alegria Zufia, Javier
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Linnaeus University, Linnaeus Knowledge Environments, Water. Halmstad University, Sweden.
    Farnelid, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Linnaeus University, Linnaeus Knowledge Environments, Water.
    Seasonal dynamics in picocyanobacterial abundance and clade composition at coastal and offshore stations in the Baltic Sea2022In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 14330Article in journal (Refereed)
    Abstract [en]

    Picocyanobacteria (< 2 mu m in diameter) are significant contributors to total phytoplankton biomass. Due to the high diversity within this group, their seasonal dynamics and relationship with environmental parameters, especially in brackish waters, are largely unknown. In this study, the abundance and community composition of phycoerythrin rich picocyanobacteria (PE-SYN) and phycocyanin rich picocyanobacteria (PC-SYN) were monitored at a coastal (K-station) and at an offshore station (LMO; similar to 10 km from land) in the Baltic Sea over three years (2018-2020). Cell abundances of picocyanobacteria correlated positively to temperature and negatively to nitrate (NO3) concentration. While PE-SYN abundance correlated to the presence of nitrogen fixers, PC-SYN abundance was linked to stratification/shallow waters. The picocyanobacterial targeted amplicon sequencing revealed an unprecedented diversity of 2169 picocyanobacterial amplicons sequence variants (ASVs). A unique assemblage of distinct picocyanobacterial clades across seasons was identified. Clade A/B dominated the picocyanobacterial community, except during summer when low NO3, high phosphate (PO4) concentrations and warm temperatures promoted S5.2 dominance. This study, providing multiyear data, links picocyanobacterial populations to environmental parameters. The difference in the response of the two functional groups and clades underscore the need for further high-resolution studies to understand their role in the ecosystem.

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  • 15.
    Alegria Zufía, Javier
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Picophytoplankton seasonal dynamics in the Baltic Sea2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Picophytoplankton (<2 μm diameter) is a diverse group of picocyanobacterial and photosynthetic picoeukaryotes (PPE).Picophytoplankton contribute significantly to total phytoplankton biomassand can dominate primary production in oceans, lakes and estuaries. In the estuarine Baltic Sea, the composition of picophytoplankton is linked to the north to south salinity gradient but knowledge of the seasonal dynamics interms of abundance, biomass and diversity is largely unknown. This thesis investigated the in situ dynamics, bottom up and top down controls of picocyanobacteria (SYN; consisting of primarily Synechococcus and Cyanobium among other genuses) and PPE at two sampling stations, one coastal and one offshore. Monitoring data over three years (2018-2020) showed high biomass contribution across all seasons. Picocyanobacterial peak abundances occurred from spring to summer at the coastal station and in late-summer to autumn at the offshore station (up to 4.7 × 105 cells mL-1).Differentiation of pigment populations showed that phycoerythrin rich(PE)-SYN was the main contributor to SYN abundances except at the coastalstation during summer, when PE-SYN and phycocyanin rich (PC)-SYN had equal contributions. PPE peak abundances occurred during late summer to autumn (up to 1.1 × 105 cells mL-1 cells ml-1). Temperature was linked topicophytoplankton growth and abundance, with PE-SYN, PCSYN and PPEadapted to different temperature ranges. Temperature also affected SYNnitrogen preference: SYN was nitrogen limited during early summer and at>15°C there was a preference for ammonium over nitrate. Clade A/B dominated the SYN community, except during summer at the coastal station when low nitrate and warm temperatures promoted S5.2 dominance. Grazing was observed to control SYN and PPE abundances and had an effect on the SYN community structure. Identification and laboratory experiments of key Synechococcus strains using a range of salinity, temperature and light conditions provided important insights into the physiological diversity of co-occurring ecotypes and links to the SYN dynamics that were observed in the field. In summary, this thesis provided novel information of picophytoplankton dynamics and community structure in the Baltic Sea. The results show that picophytoplankton play a relevant role in Baltic Sea and shows the importance of monitoring programs to understand picophytoplankton dynamics.

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  • 16.
    Alfredsson, Hanna
    University of Kalmar, School of Pure and Applied Natural Sciences. University of Kalmar, School of Pure and Applied Natural Sciences.
    Prey selection of European eel (Anguilla anguilla) larvae in the Sargasso Sea: a molecular approach.2009Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Abstract

    The European eel (Anguilla anguilla) migrates to the Sargasso Sea to spawn. Even though the biology of A. anguilla leptocephali in the Sargasso Sea has been studied for several decades, information regarding their diet has remained unknown until now. Previous dietary studies concerning other species of leptocephali in the Pacific Ocean have been limited to the recognition of identifiable prey remains amongst gut contents. Hence, in this study a molecular approach relying on the detection of prey DNA amongst gut contents was used to study dietary profiles of A. anguilla leptocephali in the Sargasso Sea.

     

    Leptocephali were collected during the circumglobal Galathea 3 expedition in spring 2007 to the Sargasso Sea. DNA extracted from gut contents were PCR amplified using universal primers targeting the nuclear 18S rRNA gene. In order to separate eel amplicons from prey amplicons, PCR products were analyzed by denaturing gradient gel electrophoresis (DGGE). Furthermore, clone libraries were constructed using universal primers targeting a portion of the 18S rRNA and mitochondrial COI gene, respectively. In total, the gut contents of 78 leptocephali were screened by DGGE.

     

    A diverse array of eukaryotic taxa was identified, hence demonstrating the applicability of a universal PCR- DGGE approach to study gut contents of leptocephali. The results presented here show, for the first time, that young stages of A. anguilla leptocephali feed on a large variety of zooplankton of which many were gelatinous (e.g. Hydrozoa, Thaliacea and Ctenophora). Several of the identified taxa also constitute important parts of the Sargasso Sea zooplankton community and are of size ranges (adult or larval stages) that made them reasonable as leptocephali prey.

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  • 17.
    Almeida, Juan Pablo
    et al.
    Lund University, Sweden.
    Rosenstock, Nicholas P.
    Lund University, Sweden.
    Forsmark, Benjamin
    Swedish University of Agricultural Sciences, Sweden.
    Bergh, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Wallander, Håkan
    Lund University, Sweden.
    Ectomycorrhizal community composition and function in a spruce forest transitioning between nitrogen and phosphorus limitation2019In: Fungal ecology, ISSN 1754-5048, E-ISSN 1878-0083, Vol. 40, p. 20-31Article in journal (Refereed)
    Abstract [en]

    Nitrogen is the main limiting nutrient in boreal ecosystems, but studies in southwest Sweden suggest that certain forests approach phosphorus (P) limitation driven by nitrogen (N) deposition. We added N, P or N + P to a Norway spruce forest in this region, to push the system to N or P limitation. Tree growth and needle nutrient concentrations indicated that the trees are P limited. EMF biomass was reduced only by N + P additions. Soil EMF communities responded more strongly to P than to N. Addition of apatite to ingrowth meshbags altered EMF community composition and enhanced the abundance of Imleria badia in the control and N plots, but not when P was added. The ecological significance of this species is discussed. Effects on tree growth, needle chemistry, and EMF communities indicate a dynamic interaction between EMF fungi and the nutrient status of trees and soils. (C) 2018 Elsevier Ltd and British Mycological Society. All rights reserved.

  • 18.
    Alneberg, Johannes
    et al.
    KTH Royal instute of technology, Sweden.
    Bennke, Christin
    Leibniz Inst Balt Sea Res, Germany.
    Beier, Sara
    Leibniz Inst Balt Sea Res, Germany;Sorbonne Univ, France.
    Bunse, Carina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Carl von Ossietzky Univ Oldenburg, Germany;Alfred Wegener Institut, Germany.
    Quince, Christopher
    Univ Warwick, UK.
    Ininbergs, Karolina
    Stockholm University, Sweden;Karolinska Institutet, Sweden.
    Riemann, Lasse
    Univ Copenhagen, Denmark.
    Ekman, Martin
    Stockholm University, Sweden.
    Juergens, Klaus
    Leibniz Inst Balt Sea Res, Germany.
    Labrenz, Matthias
    Leibniz Inst Balt Sea Res, Germany.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Linnaeus University, Linnaeus Knowledge Environments, Water.
    Andersson, Anders F.
    KTH Royal instute of technology, Sweden.
    Ecosystem-wide metagenomic binning enables prediction of ecological niches from genomes2020In: Communications Biology, E-ISSN 2399-3642, Vol. 3, no 1, p. 1-10, article id 119Article in journal (Refereed)
    Abstract [en]

    Alneberg et al. conduct metagenomics binning of water samples collected over major environmental gradients in the Baltic Sea. They use machine-learning to predict the placement of genome clusters along niche gradients based on the content of functional genes. The genome encodes the metabolic and functional capabilities of an organism and should be a major determinant of its ecological niche. Yet, it is unknown if the niche can be predicted directly from the genome. Here, we conduct metagenomic binning on 123 water samples spanning major environmental gradients of the Baltic Sea. The resulting 1961 metagenome-assembled genomes represent 352 species-level clusters that correspond to 1/3 of the metagenome sequences of the prokaryotic size-fraction. By using machine-learning, the placement of a genome cluster along various niche gradients (salinity level, depth, size-fraction) could be predicted based solely on its functional genes. The same approach predicted the genomes' placement in a virtual niche-space that captures the highest variation in distribution patterns. The predictions generally outperformed those inferred from phylogenetic information. Our study demonstrates a strong link between genome and ecological niche and provides a conceptual framework for predictive ecology based on genomic data.

  • 19. Alonso-Saez, Laura
    et al.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Pernthaler, Jakob
    Gasol, Josep M.
    Leucine-to-carbon empirical conversion factor experiments: does bacterial community structure have an influence?2010In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 12, no 11, p. 2988-2997Article in journal (Refereed)
    Abstract [en]

    The suitability of applying empirical conversion factors (eCFs) to determine bacterial biomass production remains unclear because seawater cultures are usually overtaken by phylotypes that are not abundant in situ. While eCFs vary across environments, it has not been tested whether differences in eCFs are driven by changes in bacterial community composition or by in situ environmental conditions. We carried out seawater cultures throughout a year to analyse the correlation between eCFs and bacterial community structure, analysed by catalysed reporter deposition fluorescence in situ hybridization. Gammaproteobacteria usually dominated seawater cultures, but their abundance exhibited a wide range (25–73% of cell counts) and significantly increased with inorganic nutrient enrichment. Flavobacteria were less abundant but increased up to 40% of cells counts in winter seawater cultures, when in situ chlorophyll a was high. The correlations between eCFs and the abundance of the main broad phylogenetic groups (Gamma-, Alphaproteobacteria and Flavobacteria) were significant, albeit weak, while more specific groups (Alteromonadaceae and Rhodobacteraceae) were not significantly correlated. Our results show that the frequent development of the fast-growing group Alteromonadaceae in seawater cultures does not strongly drive the observed variations in eCFs. Rather, the results imply that environmental conditions and the growth of specific phylotypes interact to determine eCFs.

  • 20.
    Alvunger, David
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Variation in number of vertebrae in populations of pike (Esox lucius) in the south-east of Sweden2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vertebral number (VN) is known to vary greatly across different taxa, but also within species orpopulations. Extensive research has shown that VN in fish is the result of interactions between geneticstructure and plastic responses to environmental cues during ontogeny. A frequently reported pattern is the tendency for VN to vary with body shape and/or length of the fish. The pike (Esox lucius) of the Baltic Sea has a complex population structure, with genetically distinct subpopulations consisting of homing anadromous individuals. Individuals belonging to these subpopulations are sympatric for most of their lives and become allopatric briefly during spawning each year. This study examined the distribution of VN in three anadromous sympatric subpopulations of pike in the Baltic. Significant differences in VN were found between juveniles and adults belonging to different subpopulations, but also across life-stageswithin all three subpopulations. Results from a common-garden experiment indicated that differences in VN among subpopulations were in part the result of genetic differences, indicative of evolutionary change. Furthermore, a quadratic regression revealed a curvilinear relationship between VN and bodylength of juveniles. Taken together, these results suggest that the combined effects of stabilizing and divergent selection might have played a role in shaping the distribution of VN in pike of the Baltic. The distribution of VN within subpopulations seems to be under the influence of stabilizing selection. Differences among subpopulations might instead reflect local adaptations driven by divergent selection. These findings signal the need for conservationists to view these subpopulations as unique units of management.

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  • 21.
    Amnebrink, Dennis
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Infection intensity and molecular characterization of eye flukes in round gobies (Neogobius melanostomus).2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The round goby (Neogobius melanostomus) is an invasive species to the Baltic Sea and is rapidly expanding its range. Apart from competition with native fish, a novel species may face, or introduce, pathogens. Previous research has shown that round gobies have a high infection rate by eye flukes of the Diplostomum genus. To study prevalence and infection intensity of Diplostomum parasites in fish in an area recently colonized by round gobies, the shallow water community of round goby, common bleak (Alburnus alburnus) and three-spined stickleback (Gasterosteus aculeatus) was examined. The fish were screened for presence of parasites in the lenses of caught fish, and abundance of parasites was compared between the host species. The round goby had the highest infection intensity of the host species, and there was no difference in infection intensity between the common bleak and three spined stickleback. To support microscopy-based identification, the parasites from the round gobies were determined to genus/species level using molecular detection and sequencing, enabling a Diplostomum species composition inventory in round gobies. Results showed that at least three species of Diplostomum infected round gobies in this population, and that there was a negative correlation between body condition and the parasite intensity indicating fitness effects resulting from infection.

  • 22.
    Andersen, K. H.
    et al.
    Tech Univ Denmark, Denmark.
    Berge, T.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark.
    Goncalves, R. J.
    Tech Univ Denmark, Denmark ;Consejo Nacl Invest Cient & Tecn, Argentina ; Estn Fotobiol Playa Union, Argentina.
    Hartvig, M.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark ; Univ Göttingen, Germany.
    Heuschele, J.
    Tech Univ Denmark, Denmark.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Tech Univ Denmark, Denmark.
    Jacobsen, N. S.
    Tech Univ Denmark, Denmark.
    Lindemann, C.
    Tech Univ Denmark, Denmark.
    Martens, E. A.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark.
    Neuheimer, A. B.
    Tech Univ Denmark, Denmark;Univ Hawaii Manoa, USA.
    Olsson, K.
    Tech Univ Denmark, Denmark.
    Palacz, A.
    Tech Univ Denmark, Denmark.
    Prowe, A. E. F.
    Tech Univ Denmark, Denmark;GEOMAR Helmholtz Ctr Ocean Res Kiel, Germany.
    Sainmont, J.
    Tech Univ Denmark, Denmark.
    Traving, S. J.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark.
    Visser, A. W.
    Tech Univ Denmark, Denmark.
    Wadhwa, N.
    Tech Univ Denmark, Denmark.
    Kiorboe, T.
    Tech Univ Denmark, Denmark.
    Characteristic Sizes of Life in the Oceans, from Bacteria to Whales2016In: Annual Review of Marine Science, ISSN 1941-1405, E-ISSN 1941-0611, Vol. 8, p. 217-241Article in journal (Refereed)
    Abstract [en]

    The size of an individual organism is a key trait to characterize its physiology and feeding ecology. Size-based scaling laws may have a limited size range of validity or undergo a transition from one scaling exponent to another at some characteristic size. We collate and review data on size-based scaling laws for resource acquisition, mobility, sensory range, and progeny size for all pelagic marine life, from bacteria to whales. Further, we review and develop simple theoretical arguments for observed scaling laws and the characteristic sizes of a change or breakdown of power laws. We divide life in the ocean into seven major realms based on trophic strategy, physiology, and life history strategy. Such a categorization represents a move away from a taxonomically oriented description toward a trait-based description of life in the oceans. Finally, we discuss life forms that transgress the simple size-based rules and identify unanswered questions.

  • 23. Andersson, J.
    et al.
    Dahl, J.
    Johansson, A.
    Karås, P.
    Nilsson, J.
    Sandström, O.
    Svensson, P. Andreas
    Utslagen fiskrekrytering och sviktande fiskbestånd i Kalmar läns kustvatten. (English title: Recruitment failure and decreasing fish stocks in the coastal areas of Kalmarsund.)2000Report (Refereed)
  • 24.
    Andersson, Kajsa
    Barometern OT.
    Svensson, Fredrik (Contributor)
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Forskningsprojekt: Alger ska rena utsläpp: "Algerna är en resurs som vi knappt använder"2014In: Baromtern, no 9 augustiArticle in journal (Other (popular science, discussion, etc.))
  • 25.
    Andersson, Martin O.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University.
    Bergvall, Ulrika A.
    Stockholm University;Swedish University of Agricultural Sciences.
    Chirico, Jan
    National Veterinary Institute.
    Christensson, Madeleine
    Swedish University of Agricultural Sciences.
    Lindgren, Per-Eric
    Linköping University;County Hospital Ryhov.
    Nordström, Jonas
    Swedish University of Agricultural Sciences;Dalarna County Administration Board.
    Kjellander, Petter
    Swedish University of Agricultural Sciences.
    Molecular detection of Babesia capreoli and Babesia venatorum in wild Swedish roe deer, Capreolus capreolus2016In: Parasites & Vectors, E-ISSN 1756-3305, Vol. 9, article id 221Article in journal (Refereed)
    Abstract [en]

    Background: The epidemiology of the zoonotic tick-transmitted parasite Babesia spp. and its occurrence in wild reservoir hosts in Sweden is unclear. In European deer, several parasite species, including Babesia capreoli and the zoonotic B. venatorum and B. divergens has been reported previously. The European roe deer, Capreolus capreolus, is an important and common part of the indigenous fauna in Europe, as well as an important host for Ixodes ricinus ticks, the vector of several Babesia spp. in Europe. Here, we aimed to investigate the occurrence of Babesia spp. in roe deer in Sweden. Findings: Roe deer (n = 77) were caught and sampled for blood. Babesia spp. was detected with a PCR assay targeting the 18S rRNA gene. The prevalence of Babesia spp. was 52 %, and two species were detected; B. capreoli and B. venatorum in 44 and 7.8 % of the individuals, respectively. Infection occurred both in summer and winter. Conclusions: We showed that roe deer in Sweden, close to the edge of their northern inland distributional range, are infected with Babesia spp. The occurrence of B. venatorum in roe deer imply that it is established in Sweden and the zoonotic implication of this finding should be regarded to a greater extent in future.

  • 26.
    Andersson, Martin O.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Vichova, Bronislava
    Slovak Acad Sci, Slovakia.
    Tolf, Conny
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Krzyzanowska, Sandra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Karlsson, Maria E.
    Swedish University of Agricultural Sciences.
    Co-infection with Babesia divergens and Anaplasma phagocytophilum in cattle (Bos taurus), Sweden2017In: Ticks and Tick-borne Diseases, ISSN 1877-959X, E-ISSN 1877-9603, Vol. 8, no 6, p. 933-935Article in journal (Refereed)
    Abstract [en]

    Babesiosis is a severe disease in cattle worldwide. In Europe, the main causative agent of bovine babesiosis is Babesia divergens. In some areas, this species is reported to have declined or even disappeared, and its etiological role overtaken by other piroplasmid species. Moreover, co-infection with other tick-transmitted pathogens can be expected to complicate diagnosis in cattle. Hence, molecular identification of the causative agent of babesiosis should be a priority. Therefore, samples from 71 domestic cattle, 39 with clinical signs of babesiosis and 32 without, from southern Sweden were screened for Babesia spp. and Anaplasma spp. using molecular methods Babesia divergens was detected in 38 of the samples, and Anaplasma phagocytophilum in 17. Co-infections with both pathogens were frequent, occurring in 18% of the animals with a B. divergens infection. The possibility of co-infection should be considered in diagnosis and treatment of bovine babesiosis.

  • 27.
    Andreas, Bendroth
    Östra Småland.
    Legrand, Catherine (Contributor)
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Algblomningens positiva sidor lyftes fram2017In: Östra Småland, no 31 Aug, p. 6-Article in journal (Other (popular science, discussion, etc.))
  • 28. Anonym, .
    Alger sprids med vinden2016In: Barometern, no 11 Juli, p. 12-Article in journal (Other (popular science, discussion, etc.))
  • 29.
    Aparicio, Fran L.
    et al.
    CSIC, Spain.
    Nieto-Cid, Mar
    CSIC, Spain.
    Borrull, Encarna
    CSIC, Spain.
    Calvo, Eva
    CSIC, Spain.
    Pelejero, Carles
    CSIC, Spain;CREA, Spain.
    Montserrat Sala, Maria
    CSIC, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gasol, Josep M.
    CSIC, Spain.
    Marrase, Celia
    CSIC, Spain.
    Eutrophication and acidification: Do they induce changes in the dissolved organic matter dynamics in the coastal Mediterranean Sea?2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 563, p. 179-189Article in journal (Refereed)
    Abstract [en]

    Two mesocosms experiments were conducted in winter 2010 and summer 2011 to examine how increased pCO(2) and/or nutrient concentrations potentially perturbate dissolved organic matter dynamics in natural microbial assemblages. The fluorescence signals of protein-and humic-like compounds were used as a proxy for labile and non-labile material, respectively, while the evolution of bacterial populations, chlorophyll a (Chl a) and dissolved organic carbon (DOC) concentrations were used as a proxy for biological activity. For both seasons, the presence of elevated pCO(2) did not cause any significant change in the DOC dynamics (p-value < 0.05). The conditions that showed the greatest changes in prokaryote abundances and Chl a content were those amended with nutrients, regardless of the change in pH. The temporal evolution of fluorophores and optical indices revealed that the degree of humification of the organic molecules and their molecular weight changed significantly in the nutrient-amended treatment. The generation of protein-like compounds was paired to increases in the prokaryote abundance, being higher in the nutrient-amended tanks than in the control. Different patterns in the magnitude and direction of the generation of humic-like molecules suggested that these changes depended on initial microbial populations and the availability of extra nutrient inputs. Based on our results, it is expected that in the future projected coastal scenarios the eutrophication processes will favor the transformations of labile and recalcitrant carbon regardless of changes in pCO(2). (c) 2016 The Authors. Published by Elsevier B.V.

  • 30.
    Arahal, David R.
    et al.
    Univ Valencia, Spain.
    Lucena, Teresa
    Univ Valencia, Spain.
    Carmen Macian, M.
    Univ Valencia, Spain.
    Ruvira, Maria A.
    Univ Valencia, Spain.
    Gonzalez, Jose M.
    Univ La Laguna, Spain.
    Lekumberri, Itziar
    Univ Girona, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pujalte, Maria J.
    Univ Valencia, Spain.
    Marinomonas blandensis sp nova, a novel marine gammaproteobacterium2016In: International Journal of Systematic and Evolutionary Microbiology, ISSN 1466-5026, E-ISSN 1466-5034, Vol. 66, p. 5544-5549Article in journal (Refereed)
    Abstract [en]

    A novel Gram-staining-negative, chemoorganotrophic, moderately halophilic, strictly aerobic bacterium, strain MED121(T), was isolated from a seawater sample collected at the Blanes Bay Microbial Observatory in the north-western Mediterranean Sea. Analysis of its 16S rRNA gene sequence, retrieved from the whole-genome sequence, showed that this bacterium was most closely related to Marinomonas dokdonensis and other Marinomonas species (96.3 and 93.3-95.7% sequence similarities, respectively), within the family Oceanospirillaceae. Strain MED121(T) was included into a whole-genome sequencing study and, subsequently, it was characterized using a polyphasic taxonomic approach. It was found to be oxidase and catalase positive, its cells are cocci to short rods, it does not ferment carbohydrates and does not reduce nitrate to nitrite or gas and it requires at least 2.5% (w/v) marine salts and tolerates up to 7% (w/v) salts. Its major cellular fatty acids in order of abundance are C-16:1 omega 7c/C-16:1 omega 6c,C-18:1 omega 7c(1), C-16:0 and C-10:0 3-OH. Its genome had an approximate length of 5.1 million bases and a DNA G+C content equal to 40.9 mol%. Analysis of the annotated genes reveals the capacity for the synthesis of ubiquinone 8 (O8) and the polar lipids phosphatidylglycerol and phosphatidylethanolannine, in agreement with other members of the genus. All the data collected supported the creation of a novel species to accommodate this bacterium, for which the name Marinomonas blandensis sp. nov. is proposed. The type strain is MED121(T) (=CECT 7076(T)=LMG 29722(T)).

  • 31.
    Arnott, Shelley E.
    et al.
    Queens Univ, Canada.
    Fugere, Vincent
    Grp Res Interuniv Limnol GRIL, Canada;Univ Quebec Trois Rivieres, Canada.
    Symons, Celia C.
    Univ Calif Irvine, USA.
    Melles, Stephanie J.
    Toronto Metropolitan Univ, Canada.
    Beisner, Beatrix E.
    Grp Res Interuniv Limnol GRIL, Canada;Univ Quebec Montreal, Canada.
    Canedo-Arguelles, Miguel
    Univ Barcelona, Spain.
    Hebert, Marie-Pier
    Grp Res Interuniv Limnol GRIL, Canada;Univ Quebec Montreal, Canada;McGill Univ, Canada.
    Brentrup, Jennifer A.
    Dartmouth Coll, USA.
    Downing, Amy L.
    Ohio Wesleyan Univ, USA.
    Gray, Derek K.
    Wilfrid Laurier Univ, Canada.
    Greco, Danielle
    Queens Univ, Canada.
    Hintz, William D.
    Univ Toledo, USA.
    McClymont, Alexandra
    Queens Univ, Canada.
    Relyea, Rick A.
    Rensselaer Polytech Inst, USA.
    Rusak, James A.
    Queens Univ, Canada;Ontario Minist Environm Conservat & Pk, Canada.
    Searle, Catherine L.
    Purdue Univ, USA.
    Astorg, Louis
    Grp Res Interuniv Limnol GRIL, Canada;Univ Quebec Montreal, Canada.
    Baker, Henry K.
    Univ Calif San Diego, USA.
    Ersoy, Zeynep
    Univ Evora, Portugal.
    Espinosa, Carmen
    Univ Vic Cent Univ Catalonia Uvic UCC, Spain.
    Franceschini, Jaclyn M.
    Wilfrid Laurier Univ, Canada.
    Giorgio, Angelina T.
    Rensselaer Polytech Inst, USA.
    Gobeler, Norman
    Univ Helsinki, Finland.
    Hassal, Emily
    Ontario Tech Univ, Canada.
    Huynh, Mercedes
    Wilfrid Laurier Univ, Canada.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Linnaeus University, Linnaeus Knowledge Environments, Water.
    Jonasen, Kacie L.
    Purdue Univ, USA.
    Kirkwood, Andrea
    Ontario Tech Univ, Canada.
    Langenheder, Silke
    Uppsala University, Sweden.
    Langvall, Ola
    Swedish University of Agricultural Sciences, Sweden.
    Laudon, Hjalmar
    Swedish University of Agricultural Sciences, Sweden.
    Lind, Lovisa
    Karlstad University, Sweden.
    Lundgren, Maria
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Moffett, Emma R.
    Univ Calif Irvine, USA.
    Proia, Lorenzo
    Univ Vic Cent Univ Catalonia Uvic UCC, Spain.
    Schuler, Matthew S.
    Montclair State Univ, USA.
    Shurin, Jonathan B.
    Univ Calif San Diego, USA.
    Steiner, Christopher F.
    Wayne State Univ, USA.
    Striebel, Maren
    Carl von Ossietzky Univ Oldenburg, Germany.
    Thibodeau, Simon
    Grp Res Interuniv Limnol GRIL, Canada;Univ Quebec Montreal, Canada.
    Cordero, Pablo Urrutia
    Uppsala University, Sweden;Lund University, Sweden.
    Vendrell-Puigmitja, Lidia
    Univ Vic Cent Univ Catalonia Uvic UCC, Spain.
    Weyhenmeyer, Gesa A.
    Uppsala University, Sweden.
    Derry, Alison M.
    Grp Res Interuniv Limnol GRIL, Canada;Univ Quebec Montreal, Canada.
    Widespread variation in salt tolerance within freshwater zooplankton species reduces the predictability of community-level salt tolerance2023In: Limnology and Oceanography Letters, E-ISSN 2378-2242, Vol. 8, no 1, p. 8-18Article in journal (Refereed)
    Abstract [en]

    The salinization of freshwaters is a global threat to aquatic biodiversity. We quantified variation in chloride (Cl-) tolerance of 19 freshwater zooplankton species in four countries to answer three questions: (1) How much variation in Cl- tolerance is present among populations? (2) What factors predict intraspecific variation in Cl- tolerance? (3) Must we account for intraspecific variation to accurately predict community Cl- tolerance? We conducted field mesocosm experiments at 16 sites and compiled acute LC(50)s from published laboratory studies. We found high variation in LC(50)s for Cl- tolerance in multiple species, which, in the experiment, was only explained by zooplankton community composition. Variation in species-LC50 was high enough that at 45% of lakes, community response was not predictable based on species tolerances measured at other sites. This suggests that water quality guidelines should be based on multiple populations and communities to account for large intraspecific variation in Cl- tolerance.

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  • 32. Aura, Christopher
    et al.
    Raburu, Philip
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Macroinvertebrates’ community structure in Rivers Kipkaren and Sosiani, River Nzoia basin, Kenya2011In: Journal of Ecology and the Natural Environment, E-ISSN 2006-9847, Vol. 3, no 2, p. 39-46Article in journal (Refereed)
    Abstract [en]

    Benthic macroinvertebrates from Rivers Kipkaren and Sosiani in the upper reaches of River Nzoiabasin, Kenya, were sampled semi-quantitatively monthly from December 2006 to May 2007 using a0.5 mm mesh size scoop net in the riffles, pools and runs. Seven sampling sites were selected on theareas of the rivers along a longitudinal gradient in relation to anthropogenic impact. Physicochemicalparameters were measured in situ, while specific chemical parameters were determinedcalometrically in the laboratory using standard methods. Habitat and land use characteristics werealso recorded. A total of 1499 macroinvertebrates belonging to 13 orders, 28 families and 31 generawere collected. The orders Ephemeroptera, Hemiptera and Coleoptera were taxonomically richest.Overall, a total of 31 genera for River Kipkaren dominated by the EPT and 19 macroinvertebrategenera for the lower River Sosiani dominated by dipterans were recorded. Conductivity, oxygen andtotal nitrogen varied significantly (p < 0.05) between sampled sites, but not temporally. The results ofredundancy analysis using 9 dominant macroinvertebrate genera revealed a distinction betweenimpacted and the less impacted sites and the physico-chemical parameters associated with thisdistinction.

  • 33.
    Avril, Alexis
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Grosbois, Vladimir
    CIRAD, France.
    Latorre-Margalef, Neus
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Georgia, USA.
    Gaidet, Nicolas
    CIRAD, France.
    Tolf, Conny
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Olsen, Björn
    Uppsala University.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Capturing individual-level parameters of influenza A virus dynamics in wild ducks using multistate models2016In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 53, no 4, p. 1289-1297Article in journal (Refereed)
    Abstract [en]

    Disease prevalence in wildlife is governed by epidemiological parameters (infection and recovery rates) and response to infection, both of which vary within and among individual hosts. Studies quantifying these individual-scale parameters and documenting their source of variation in wild hosts are fundamental for predicting disease dynamics. Such studies do not exist for the influenza A virus (IAV), despite its strong impact on the global economy and public health. Using capture-recaptures of 3500 individual mallards Anas platyrhynchos during seven migration seasons at a stopover site in southern Sweden, we provide the first empirical description of the individual-based mechanisms of IAV dynamics in a wild reservoir host. For most years, prevalence and risk of IAV infection peaked at a single time during the autumn migration season, but the timing, shape and intensity of the infection curve showed strong annual heterogeneity. In contrast, the seasonal pattern of recovery rate only varied in intensity across years. Adults and juveniles displayed similar seasonal patterns of infection and recovery each year. However, compared to adults, juveniles experienced twice the risk of becoming infected, whereas recovery rates were similar across age categories. Finally, we did not find evidence that infection influenced the timing of emigration.Synthesis and applications. Our study provides robust empirical estimates of epidemiological parameters for predicting influenza A virus (IAV) dynamics. However, the strong annual variation in infection curves makes forecasting difficult. Prevalence data can provide reliable surveillance indicators as long as they catch the variation in infection risk. However, individual-based monitoring of infection is required to verify this assumption in areas where surveillance occurs. In this context, monitoring of captive sentinel birds kept in close contact with wild birds is useful. The fact that infection does not impact the timing of migration underpins the potential for mallards to spread viruses rapidly over large geographical scales. Hence, we strongly encourage IAV surveillance with a multistate capture-recapture approach along the entire migratory flyway of mallards.

  • 34.
    Avril, Alexis
    et al.
    ONCFS, France.
    Letty, Jerome
    ONCFS, Direct Etud & Rech, F-34990 Juvignac, France.
    Leonard, Yves
    ONCFS, F-45370 Dry, France.
    Pontier, Dominique
    Univ Lyon .
    Exploration forays in juvenile European hares (Lepus europaeus): dispersal preludes or hunting-induced troubles?2014In: BMC Ecology, E-ISSN 1472-6785, Vol. 14, article id 6Article in journal (Refereed)
    Abstract [en]

    Background: Movements of animals have important consequences, at both the individual and population levels. Due to its important implications in the evolutionary dynamics of populations, dispersal is one of the most studied types of movement. In contrast, non-permanent extra home-range movements are often paid less attention. However, these movements may occur in response to important biological processes such as mating or predation avoidance. In addition, these forays are often preludes to permanent dispersal, because they may help individuals gain cues about their surroundings prior to settlement in a new place. In the European hare, exploration forays occur predominantly in juveniles, the time at which most hares disperse. In France, the timing of dispersal also overlaps with the hare hunting period. However, the determinants of such behaviour have not yet been studied. Herein, we investigate whether these non-permanent explorations are dispersal attempts/preludes or, in contrast, whether they are triggered by other factors such as disturbances related to hunting. Results: Contrary to natal dispersal, we did not find strong male-bias in the propensity to engage in explorations. Exploration forays occurred less in juveniles than in adults and later in the season than natal dispersal. This was the case both for philopatric movements and for movements occurring after dispersal and settlement. These movements were also more likely to occur during the hare hunting period and the mating season. Conclusions: We suggest that explorations in hares are triggered by factors other than dispersal and that hares may respond to hunting disturbances. Overall, we emphasize the need to account for human-related predation risk as a factor driving space-use in harvested species.

  • 35.
    Azizi, Soghra
    et al.
    Tarbiat Modares Univ, Iran.
    Kouchaksaraei, Masoud Tabari
    Tarbiat Modares Univ, Iran.
    Hadian, Javad
    Shahid Beheshti Univ, Iran.
    Abad, Ali Reza Fallah Nosrat
    Agr Res Educ & Extens Org AREEO, Iran.
    Sanavi, Seyed Ali Mohammad Modarres
    Tarbiat Modares Univ, Iran.
    Ammer, Christian
    Georg August Univ Gottingen, Germany.
    Bader, Martin K.-F.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology. Auckland Univ Technol, New Zealand.
    Dual inoculations of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria boost drought resistance and essential oil yield of common myrtle2021In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 497, article id 119478Article in journal (Refereed)
    Abstract [en]

    Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) are increasingly being used to enhance crop abiotic stress resistance. Common myrtle is an economically important essential oilproducing plant but knowledge about its drought resistance mechanisms and the drought mitigation potential of AMF and PGPR is scant. Here, we investigated the effects of single and dual AMF (Funneliformis mosseae, Rhizophagus irregularis) and PGPR (Pseudomonas fluorescens, P. putida) inoculation on seedling survival, growth, physiology, and biochemical traits under soil water deficit (100%, 60%, and 30% of field capacity). Under severe drought, all inoculations increased survival compared to non-inoculated seedlings. Drought-related growth impairment was more strongly compensated belowground than aboveground, especially in dual-inoculated plants, indicating prioritized resource allocation to roots probably linked to AMF- and PGPR-induced phytohormone changes. Particularly dual inoculation significantly improved leaf physiology, reduced electrolyte leakage, malondialdehyde, and proline concentrations and mitigated oxidative pigment losses under drought through upregulation of the antioxidant defense as evidenced by (non-)enzymatic antioxidant accumulation, including essential oils. Our findings indicate similarly significant AMF- and PGPR-mediated boosts in myrtle drought resistance through enhanced water and nutrient supply and stimulation of the antioxidant defense. Dual inoculations proved most effective and provide a low-cost approach to optimizing myrtle cultivation and restoration programs.

  • 36.
    Baeck, Jonathan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    How using live bait affects longline bycatch in the artisanal fishing fleet of Costa Rica: The dilemma between live and dead bait2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Long-lining is a frequently used method in marine fisheries. Similarly to trawling and nets, also long-lining is associated with bycatch which may have negative impacts on the ecosystems. However, different methods of long-lining may vary in the amount and ratio of bycatch but methods have rarely been compared directly. This study investigates whether the fishing method of floated demersal longlining baited with live Pacific Anchoveta (Cetengraulis mysticetus) has a lower bycatch ratio or bycatch amount than using demersal long lines baited with filet pieces of dead fish. The study was carried out in collaboration with artisanal small-scale fishermen in the Paquera area of the Gulf of Nicoya in Costa Rica. Six efforts were made in February of 2023, and were then compared to dead bait data from the same area from 2015 and 2016 collected by Universidad Nacional de Costa Rica. This comparison showed no significant difference between the two methods in bycatch ratio but showed that live bait longlining captures significantly more total fish and bycatch per catch per unit effort (CPUE). There are also ethical issues and issues with bait fish acquirement that points against live bait fishing. However, there are certain arguments in support of the method, such as broadening the exploitation strain across more species and not hindering financially struggling artisanal fishermen further.   

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  • 37.
    Baltar, Federico
    et al.
    Univ Las Palmas Gran Canaria, Spain.
    Arístegui, Javier
    Gasol, Josep M
    Herndl, Gerhard J
    Microbial functioning and community structure variability in the mesopelagic and epipelagic waters of the subtropical Northeast Atlantic Ocean.2012In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 78, no 9, p. 3309-3316Article in journal (Refereed)
    Abstract [en]

    We analyzed the regional distribution of bulk heterotrophic prokaryotic activity (leucine incorporation) and selected single-cell parameters (cell viability and nucleic acid content) as parameters for microbial functioning, as well as bacterial and archaeal community structure in the epipelagic (0-200 m) and mesopelagic (200-1000 m) subtropical Northeast Atlantic Ocean. We selectively sampled three contrasting regions covering a wide range of surface productivity and oceanographic properties within the same basin: (i) the eddy field south of the Canary Islands, (ii) the open-ocean Subtropical Gyre and (iii) the upwelling filament off Cape Blanc. In the epipelagic waters, a high regional variation in hydrographic parameters and bacterial community structure was detected accompanied, however, by a low variability in microbial functioning. In contrast, mesopelagic microbial functioning was highly variable between the studied regions despite the homogeneous abiotic conditions found therein. More microbial functioning parameters indicated differences among the three regions within the mesopelagic (i.e., viability of cells, nucleic acid content, cell-specific heterotrophic activity, nanoflagellate abundance, prokaryotic to nanoflagellate abundance ratio) than in the epipelagic (i.e., bulk activity, nucleic acid content and nanoflagellate abundance) waters. Our results show that the mesopelagic realm in the NE Atlantic is, in terms of microbial activity, more heterogeneous than its epipelagic counterpart, probably linked to mesoscale hydrographical variations.

  • 38.
    Baltar, Federico
    et al.
    Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira,.
    Arístegui, Javier
    Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira,.
    Gasol, Josep M.
    Herndl, Gerhard J.
    Prokaryotic carbon utilization in the dark ocean: : growth efficiency, leucine-to-carbon conversion factors, and their relation2010In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 60, no 3, p. 227-232Article in journal (Refereed)
    Abstract [en]

    Experiments were conducted in the mesopelagic subtropical northeast Atlantic Ocean to determine the range of variability in the prokaryotic leucine-to-carbon conversion factor (CF), and prokaryotic growth efficiency (PGE). The way prokaryotic heterotrophic production (PHP) is calcu- lated directly influences PGE (variations of PGE between 1 and 31% were found for a single sample). The empirically obtained deep-water CFs showed a 7-fold variability (0.13 to 0.85 kg C mol–1 Leu), but were always lower than the theoretical CF of 1.55 kg C mol–1 Leu assuming no isotope dilution. Empirically determined CFs were highly correlated to PGE, suggesting that both parameters are rep- resentations of the same basic metabolic processes. Overall, the PGEs obtained in this study suggest that mesopelagic prokaryotic assemblages can sometimes be as important in carbon processing as their epipelagic counterparts.

     

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  • 39.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Gasol, Josep M.
    Lekunberri, Itziar
    Herndl, Gerhard J.
    Mesoscale eddies: hot-spots for prokaryotic diversity and function in the ocean2010In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 4, p. 975-988Article in journal (Refereed)
    Abstract [en]

    To investigate the effects of mesoscale eddies on prokaryotic assemblage structure and activity, we sampled two cyclonic eddies (CEs) and two anticyclonic eddies (AEs) in the permanent eddy-field downstream the Canary Islands. The eddy stations were compared with two far-field (FF) stations located also in the Canary Current, but outside the influence of the eddy field. The distribution of prokaryotic abundance (PA), bulk prokaryotic heterotrophic activity (PHA), various indicators of single-cell activity (such as nucleic acid content, proportion of live cells, and fraction of cells actively incorporating leucine), as well as bacterial and archaeal community structure were determined from the surface to 2000 m depth. In the upper epipelagic layer (0–200 m), the effect of eddies on the prokaryotic community was more apparent, as indicated by the higher PA, PHA, fraction of living cells, and percentage of active cells incorporating leucine within eddies than at FF stations. Prokaryotic community composition differed also between eddy and FF stations in the epipelagic layer. In the mesopelagic layer (200–1000 m), there were also significant differences in PA and PHA between eddy and FF stations, although in general, there were no clear differences in community composition or single-cell activity. The effects on prokaryotic activity and community structure were stronger in AE than CE, decreasing with depth in both types of eddies. Overall, both types of eddies show distinct community compositions (as compared with FF in the epipelagic), and represent oceanic ‘hotspots’ of prokaryotic activity (in the epi- and mesopelagic realms).

  • 40.
    Baltar, Federico
    et al.
    Univ Las Palmas Gran Canaria, Fac Ciencias Mar, Las Palmas Gran Canaria 35017, Spain.
    Arístegui, Javier
    Gasol, Josep M.
    Sintes, Eva
    Herndl, Gerhard J.
    Evidence of prokaryotic metabolism on suspended particulate organic matter in the dark waters of the (sub)tropical North Atlantic2009In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 54, no 1, p. 182-193Article in journal (Refereed)
    Abstract [en]

    The distribution of prokaryotic abundance (PA), respiratory activity (ETS), heterotrophic production (PHP), and suspended particulate (POM) and dissolved (DOM) organic matter was determined in the meso- and bathypelagic waters of the (sub) tropical North Atlantic. PA decreased by one order of magnitude from the lower euphotic zone to the bathypelagic waters, while ETS decreased by two and PHP by three orders of magnitude. On a section following the Mid-Atlantic Ridge from 35 degrees N to 5 degrees N, ETS below 1000-m depth increased southwards up to three-fold. This latitudinal gradient in the deep waters was paralleled by a six-fold increase in Particulate Organic Carbon (POC), whereas no trend was apparent in the DOM distribution. Significant correlations between POM and ETS were obtained in the water masses between 1000-m and 3000-m depth, the Antarctic Intermediate Water and the North East Atlantic Deep Water. A strong imbalance in the dark ocean was found between prokaryotic carbon demand (estimated through two different approaches) and the carbon sinking flux derived from sediment-trap records corrected with Th-230. The imbalance was greater when deeper in the water column, suggesting that the suspended carbon pool must account for most of the carbon deficit. Our results, together with other recent findings discussed in this paper, indicate that microbial life in the dark ocean is likely more dependent on slowly sinking or buoyant, laterally advected suspended particles than hitherto assumed. 

  • 41.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Gasol, Josep M.
    Sintes, Eva
    van Aken, Hendrik M.
    Herndl, Gerhard J.
    High dissolved extracellular enzymatic activity in the deep Central Atlantic Ocean2010In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 58, no 3, p. 287-302Article in journal (Refereed)
    Abstract [en]

    The distribution of prokaryotic abundance (PA), prokaryotic heterotrophic production (PHP), and suspended particulate organic material (POM), as well as total and dissolved (operationally defined as passing through 0.2 mu m pore size filters) potential extracellular enzymatic activities (EEA; alpha- and beta-glucosidase [AGase and BGase], leucine aminopeptidase [LAPase], and alkaline phosphatase [APase]) were determined in the meso- and bathypelagic waters of the (sub)tropical Atlantic along an eastern zonal transatlantic transect and a western N-S transect. Significant differences between both transects were found for POM concentration but not for PA, PHP (except in the subsurface and oxygen minimum layer), and dissolved and total EEA. PHP decreased by 3 orders of magnitude from the lower euphotic zone to bathypelagic waters, while PA and cell-specific PHP decreased only by 1 and 2 orders of magnitude, respectively. The proportion of the dissolved to the total EEA was high in the dark ocean for all the enzymes, ranging from 54 to 100, 56 to 100, 65 to 100 and 57 to 97 % for AGase, BGase, LAPase and APase, respectively. The kinetic parameters (V-max, and K-m) of both the dissolved and total fractions of LAPase and APase were very similar throughout the water column, suggesting a similar origin for both dissolved and particulate EEA. Significant correlations of both dissolved and total EEA were found with prokaryotic metabolism and the POM pool. Based on the previous notion that the fraction of dissolved EEA is higher in particle-attached than in free-living microbes, our results suggest that microbial activity in the dark ocean occurs mainly on colloidal and particulate material. This is in agreement with recent genomic evidence. However, these colloidal and particulate materials are prone to disruption during the sampling process. Hence, more selective sampling techniques are needed to specifically collect these deep-water aggregates that probably represent hotspots of microbial activity in the deep ocean.

  • 42.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Universidad de Las Palmas de Gran Canaria, Spain.
    Arístegui, Javier
    Universidad de Las Palmas de Gran Canaria, Spain.
    Gasol, Josep M.
    Yokokawa, Taichi
    Royal Netherlands Institute for Sea Research, Netherlands.
    Herndl, Gerhard J.
    University of Vienna, Austria.
    Bacterial Versus Archaeal Origin of Extracellular Enzymatic Activity in the Northeast Atlantic Deep Waters2013In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 65, no 2, p. 277-288Article in journal (Refereed)
    Abstract [en]

    We determined the total and dissolved extracellularenzymatic activity (EEA) of α-glucosidase and β-glucosidase(AGase and BGase), alkaline phosphatase (APase) and leucineaminopeptidase (LAPase) activities in the epi-, meso- andbathypelagic waters of the subtropical Northeast Atlantic.EEA was also determined in treatments in which bacterialEEAwas inhibited by erythromycin. Additionally, EEA decayexperiments were performed with surface and deep waters todetermine EEA lifetimes in both water masses. The proportionof dissolved to total EEA (66–89 %, 44–88 %, 57–82 % and86–100 % for AGase, BGase, APase and LAPase, respectively)was generally higher than the cell-associated (i.e.,particulate) EEA. The percentage of dissolved to total EEAwas inversely proportional to the percentage of erythromycininhibitedto total EEA. Since erythromycin-inhibited plusdissolved EEA equaled total EEA, this tentatively suggeststhat cell-associated EEA in the open oceanic water column isalmost exclusively of bacterial origin. The decay constants ofdissolved EEAwere in the range of 0.002–0.048 h−1 dependingon the type of extracellular enzyme, temperature and depthin the water column. Although dissolved EEA can have differentorigins, the major contribution of Bacteria to cellassociatedEEA and the long life-time of dissolved EEAsuggest that Bacteria—and not mesophilic Archaea—areessentially the main producers of EEA in the open subtropicalNortheast Atlantic down to bathypelagic layers.

  • 43.
    Baltar, Federico
    et al.
    Univ Las Palmas Gran Canaria, Fac Ciencias Mar, Las Palmas Gran Canaria 35017, Spain.
    Arístegui, Javier
    Herndl, Gerhard J
    Gasol, Josep M
    Hernández-León, Santiago
    Strong coast-ocean and surface-depth gradients in prokaryotic assemblage structure and activity in a coastal transition zone region2007In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 50, no 1, p. 63-74Article in journal (Refereed)
    Abstract [en]

    The distribution of marine Crenarchaeota Group 1, marine Euryarchaeota Group II and some major groups of Bacteria (SAR 11, Roseobacter, Gammaproteobacteria and Bacteroidetes) was investigated in the North Atlantic water column (surface to 2000 m depth) along a transect from the coastal waters of the NW African upwelling to the offshore waters of the Canary Coastal Transition Zone (CTZ). Catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) was used to describe the prokaryotic assemblages. Bulk picoplankton abundance and leucine incorporation were determined. Pronounced changes in prokaryotic assemblage composition were observed from the coast to the open ocean and at the deep chlorophyll maximum (DCM) with decreasing bulk heterotrophic activity. All bacterial groups decreased in absolute abundances from the coast to the open ocean; both archaeal groups increased towards the open ocean. Prokaryotic abundance and activity decreased 2 and 3 orders of magnitude, respectively, from the surface to 2000 m. Prokaryotic growth rates were high in the mesopelagic zone (similar to 0.13 d(-)1), compared to other reports from the central North Atlantic. SARI 1 in total picoplankton abundance decreased from 42 % in the DCM to 4 % at 2000 m, while marine Crenarchaeota Group I increased from 1 % in the DCM to 39 % in the oxygen minimum layer. A clear influence of the different intermediate water masses was observed on the bulk heterotrophic picoplankton activity, with lower leucine incorporation rates corresponding to layers where patches of Antarctic Intermediate Water were detected. Coast-ocean and surface-depth gradients in bulk prokaryotic abundance and production and assemblage composition were comparable to changes observed in basin-scale studies, pinpointing the CTZs as regions of strong variability in microbial diversity and metabolism. 

  • 44.
    Baltar, Federico
    et al.
    Univ Las Palmas Gran Canaria, Fac Ciencias Mar, Las Palmas Gran Canaria 35017, Spain .
    Arístegui, Javier
    Montero, María F.
    Espino, Minerva
    Gasol, Josep M.
    Herndl, Gerhard J.
    Mesoscale variability modulates seasonal changes in the trophic structure of nano- and picoplankton communities across the NW Africa-Canary Islands transition zone2009In: Progress in Oceanography, ISSN 0079-6611, E-ISSN 1873-4472, Vol. 83, no 1-4, p. 180-188Article in journal (Refereed)
    Abstract [en]

    The variability of picoplankton and nanoplankton autotrophic (A) and heterotrophic (H) communities was studied along a zonal gradient extending from the NW African shelf to 500 km offshore in two contrasting seasons of the year: early spring (spring) and summer (summer). Plankton abundance was significantly higher in summer than in spring. In particular, heterotrophic prokaryotes (HP) and Prochlorococcus (Proc) were an order of magnitude more abundant in summer, presumably due to a higher loading of dissolved organic matter and higher temperatures. The average ratio of A to H biomass was lower during the summer. Over the African shelf, picoplankton was lowest during summer, while both the autotrophic and heterotrophic nanoflagellates (ANF and HNF) showed the highest abundances. In contrast, in spring, the highest abundance of Picoeukaryotes (PE) and Synechococcus (Syn) was found over or close to the shelf. The offshore sampling sections intersected a complex area of strong mesoscale variability, which affected the plankton distribution. In summer, the entrainment of an upwelling filament around a cyclonic eddy provoked the increase of HP and Syn abundances by about one order of magnitude over the surrounding waters, while PE were more abundant over the core of the eddy (probably due to nutrient pumping). In spring, HP and Syn were more abundant at the boundaries of an anticyclonic eddy and in the filament (where PE also increased). Proc abundance increased up to one order of magnitude in the core of the eddy and in the eddy-oceanic waters front. ANF and HNF showed the highest abundances in the filament and the eddy. in summary, although seasonality affects the background variability in microplankton communities, the mesoscale variability found in the Canary Islands transition zone strongly modulates the patterns of distribution, abundances and changes in community structure, altering the A to H ratio and concomitantly playing a key role modifying the carbon pathways within the food web in the region. 

  • 45.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Sintes, Eva
    Reinthaler, Thomas
    Gasol, Josep M.
    Herndl, Gerhard J.
    Significance of non-sinking particulate organic carbon and dark CO2 fixation to heterotrophic carbon demand in the mesopelagic Atlantic2010In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 37, p. L09602-Article in journal (Refereed)
    Abstract [en]

    It is generally assumed that sinking particulate organic carbon (POC) constitutes the main source of organic carbon supply to the deep ocean's food webs. However, a major discrepancy between the rates of sinking POC supply (collected with sediment traps) and the prokaryotic organic carbon demand (the total amount of carbon required to sustain the heterotrophic metabolism of the prokaryotes; i.e., production plus respiration, PCD) of deep-water communities has been consistently reported for the dark realm of the global ocean. While the amount of sinking POC flux declines exponentially with depth, the concentration of suspended, buoyant non-sinking POC (nsPOC; obtained with oceanographic bottles) exhibits only small variations with depth in the (sub) tropical Northeast Atlantic. Based on available data for the North Atlantic we show here that the sinking POC flux would contribute only 4-12% of the PCD in the mesopelagic realm (depending on the primary production rate in surface waters). The amount of nsPOC potentially available to heterotrophic prokaryotes in the mesopelagic realm can be partly replenished by dark dissolved inorganic carbon fixation contributing between 12% to 72% to the PCD daily. Taken together, there is evidence that the mesopelagic microheterotrophic biota is more dependent on the nsPOC pool than on the sinking POC supply. Hence, the enigmatic major mismatch between the organic carbon demand of the deep-water heterotrophic microbiota and the POC supply rates might be substantially smaller by including the potentially available nsPOC and its autochthonous production in oceanic carbon cycling models. Citation: Baltar, F., J. Aristegui, E. Sintes, J. M. Gasol, T. Reinthaler, and G. J. Herndl (2010), Significance of non-sinking particulate organic carbon and dark CO2 fixation to heterotrophic carbon demand in the mesopelagic northeast Atlantic.

  • 46.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Otago, New Zealand.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 9, p. 2815-2821Article in journal (Refereed)
    Abstract [en]

    Extracellular enzymatic activities (EEA) are a crucial step on the degradation of organic matter. Dissolved (cell-free) extracellular enzymes in seawater can make up a significant contribution of the bulk EEA. However, the factors controlling the proportion of dissolved EEA in the marine environment remain unknown. Here we studied the seasonal changes in the proportion of dissolved relative to total EEA (of alkaline phosphatase [APase], β-glucosidase, [BGase], and leucine aminopeptidase, [LAPase]), in the Baltic Sea for 18 months. The proportio n of dissolved EEA ranged between 37-100%, 0-100%, 34-100% for APase, BGase and LAPase, respectively. A consistent seasonal pattern in the proportion of dissolved EEA was found among all the studied enzymes, with values up to 100% during winter and <40% du ring summer. A significant negative relation was found between the 21proportion of dissolved EEA and temperature, indicating that temperature might be a critical factor controlling the proportion of dissolved relative to total EEA in marine environments. Our results suggest a strong decoupling of hydrolysis rates from mi crobial dynamics in cold waters. This implies that under cold conditions, cell-free enzymes can contribute to substrate availability at large distances from the producing cell, increasing the dissociation between the hydrolysis of organic compounds and the actual microbes producing the enzymes. This also indicates that global warming could come to affect the hydrolysis of organic matter by reducing the hydrolytic activity of cell-free enzymes.

  • 47.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Lindh, Markus V.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Parparov, Arkadi
    Israel Oceanographic and Limnological Research.
    Berman, Tom
    Israel Oceanographic and Limnological Research.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Prokaryotic community structure and respiration during long-term incubations2012In: MicrobiologyOpen, E-ISSN 2045-8827, Vol. 1, no 2, p. 214-224Article in journal (Refereed)
    Abstract [en]

    Despite the importance of incubation assays for studies inmicrobial ecology that frequentlyrequire long confinement times, few reports are available in which changesin the assemblage structure of aquatic prokaryotes were monitored during longtermincubations.We measured rates of dissolved organic carbon degradation andmicrobial respiration by consumption of dissolved oxygen (DO) in four experimentswith Lake Kinneret near-surface water and, concomitantly, we analyzed thevariability in prokaryotic community structure during long-term dark bottle incubations.During the first 24 h, therewere only minor changes in bacterial communitycomposition. Thereafter there were marked changes in the prokaryotic communitystructure during the incubations. In contrast, oxygen consumption rates (a proxyfor both respiration and dissolved organic carbon degradation rates) remained stablefor up to 10–23 days. This study is one of the first to examine closely the phylogeneticchanges that occur in the microbial community of untreated freshwaterduring long-term (days) incubations in dark, sealed containers. Novel informationon the diversity of the main bacterial phylotypes that may be involved in dissolvedorganic matter degradation in lake Kinneret is also provided. Our results suggestthat, under certain ecological settings, constant community metabolic rates can bemaintained as a result of shifts in community composition.

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  • 48.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Otago, New Zealand.
    Lundin, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Palovaara, Joakim
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lekunberri, Itziar
    Univ Vienna, Austria;Inst Catala Recerca Aigua, Spain.
    Reinthaler, Thomas
    Univ Vienna, Austria.
    Herndl, Gerhard J.
    Univ Vienna, Austria;Univ Utrecht, Netherlands.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Prokaryotic Responses to Ammonium and Organic Carbon Reveal Alternative CO2 Fixation Pathways and Importance of Alkaline Phosphatase in the Mesopelagic North Atlantic2016In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 7, article id 1670Article in journal (Refereed)
    Abstract [en]

    To decipher the response of mesopelagic prokaryotic communities to input of nutrients, we tracked changes in prokaryotic abundance, extracellular enzymatic activities, heterotrophic production, dark dissolved inorganic carbon (DIC) fixation, community composition (16S rRNA sequencing) and community gene expression (metatranscriptomics) in 3 microcosm experiments with water from the mesopelagic North Atlantic. Responses in 3 different treatments amended with thiosulfate, ammonium or organic matter (i.e., pyruvate plus acetate) were compared to unamended controls. The strongest stimulation was found in the organic matter enrichments, where all measured rates increased >10-fold. Strikingly, in the organic matter treatment, the dark DIC fixation rates-assumed to be related to autotrophic metabolisms-were equally stimulated as all the other heterotrophic-related parameters. This increase in DIC fixation rates was paralleled by an up-regulation of genes involved in DIC assimilation via anaplerotic pathways. Alkaline phosphatase was the metabolic rate most strongly stimulated and its activity seemed to be related to cross-activation by nonpartner histidine kinases, and/or the activation of genes involved in the regulation of elemental balance during catabolic processes. These findings suggest that episodic events such as strong sedimentation of organic matter into the mesopelagic might trigger rapid increases of originally rare members of the prokaryotic community, enhancing heterotrophic and autotrophic carbon uptake rates, ultimately affecting carbon cycling. Our experiments highlight a number of fairly unstudied microbial processes of potential importance in mesopelagic waters that require future attention.

  • 49.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Otago, New Zealand.
    Palovaara, Joakim
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Wageningen University, The Netherlands.
    Unrein, Fernando
    Institut de Ciències del Mar CSIC, Spain.
    Catala, Philippe
    Pierre-and-Marie-Curie University, France.
    Hornak, Karel
    Biology Centre of the Academy of Sciences of the Czech Republic, Czech Republic.
    Simek, Karel
    Biology Centre of the Academy of Sciences of the Czech Republic, Czech Republic.
    Vaque, Dolors
    Institut de Ciències del Mar CSIC, Spain.
    Massana, Ramon
    Institut de Ciències del Mar CSIC, Spain.
    Gasol, Josep M.
    Institut de Ciències del Mar CSIC, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Marine bacterial community structure resilience to changes in protist predation under phytoplankton bloom conditions2016In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 10, no 3, p. 568-581Article in journal (Refereed)
    Abstract [en]

    To test whether protist grazing selectively affects the composition of aquatic bacterial communities, we combined high-throughput sequencing to determine bacterial community composition with analyses of grazing rates, protist and bacterial abundances and bacterial cell sizes and physiological states in a mesocosm experiment in which nutrients were added to stimulate a phytoplankton bloom. A large variability was observed in the abundances of bacteria (from 0.7 to 2.4 x 10(6) cells per ml), heterotrophic nanoflagellates (from 0.063 to 2.7 x 10(4) cells per ml) and ciliates (from 100 to 3000 cells per l) during the experiment (similar to 3-, 45- and 30-fold, respectively), as well as in bulk grazing rates (from 1 to 13 x 10(6) bacteria per ml per day) and bacterial production (from 3 to 379 mu g per Cl per day) (1 and 2 orders of magnitude, respectively). However, these strong changes in predation pressure did not induce comparable responses in bacterial community composition, indicating that bacterial community structure was resilient to changes in protist predation pressure. Overall, our results indicate that peaks in protist predation (at least those associated with phytoplankton blooms) do not necessarily trigger substantial changes in the composition of coastal marine bacterioplankton communities.

  • 50.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Otago, New Zealand.
    Palovaara, Joakim
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Vila-Costa, Maria
    Univ Barcelona, Spain.
    Salazar, Guillem
    CSIC, Spain.
    Calvo, Eva
    CSIC, Spain.
    Pelejero, Carles
    CSIC, Spain ; Inst Catalana Recerca & Estudis Avancats, Spain.
    Marrase, Celia
    CSIC, Spain.
    Gasol, Josep M.
    CSIC, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Response of rare, common and abundant bacterioplankton to anthropogenic perturbations in a Mediterranean coastal site2015In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 91, no 6, article id UNSP fiv058Article in journal (Refereed)
    Abstract [en]

    Bacterioplankton communities are made up of a small set of abundant taxa and a large number of low-abundant organisms (i.e. 'rare biosphere'). Despite the critical role played by bacteria in marine ecosystems, it remains unknown how this large diversity of organisms are affected by human-induced perturbations, or what controls the responsiveness of rare compared to abundant bacteria. We studied the response of a Mediterranean bacterioplankton community to two anthropogenic perturbations (i.e. nutrient enrichment and/or acidification) in two mesocosm experiments (in winter and summer). Nutrient enrichment increased the relative abundance of some operational taxonomic units (OTUs), e.g. Polaribacter, Tenacibaculum, Rhodobacteraceae and caused a relative decrease in others (e.g. Croceibacter). Interestingly, a synergistic effect of acidification and nutrient enrichment was observed on specific OTUs (e.g. SAR86). We analyzed the OTUs that became abundant at the end of the experiments and whether they belonged to the rare (<0.1% of relative abundance), the common (0.1-1.0% of relative abundance) or the abundant (>1% relative abundance) fractions. Most of the abundant OTUs at the end of the experiments were abundant, or at least common, in the original community of both experiments, suggesting that ecosystem alterations do not necessarily call for rare members to grow.

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