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  • 1.
    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.

  • 2.
    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.

  • 3.
    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.

  • 4. 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)
  • 5.
    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.

  • 6. 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.

  • 7.
    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.

  • 8.
    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.

  • 9.
    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.

  • 10. 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)
  • 11.
    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.))
  • 12.
    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, ISSN 1756-3305, 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.

  • 13.
    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.

  • 14.
    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.))
  • 15. Anonym, .
    Alger sprids med vinden2016In: Barometern, no 11 Juli, p. 12-Article in journal (Other (popular science, discussion, etc.))
  • 16.
    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.

  • 17.
    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)).

  • 18. 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, ISSN 2006-9847, 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.

  • 19.
    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.

  • 20.
    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, ISSN 1472-6785, 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.

  • 21.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    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.

  • 22.
    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.

     

  • 23.
    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).

  • 24.
    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. 

  • 25.
    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.

  • 26.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Las Palmas Gran Canaria, Inst Oceanog & Cambio Global, Gran Canaria 35214, Spain.
    Arístegui, Javier
    Universidad de Las Palmas de Gran Canaria.
    Gasol, Josep M.
    Yokokawa, Taichi
    Royal Netherlands Institute for Sea Research.
    Herndl, Gerhard J.
    University of Vienna.
    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.

  • 27.
    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. 

  • 28.
    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. 

  • 29.
    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.

  • 30.
    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.

  • 31.
    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, ISSN 2045-8827, 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.

  • 32.
    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, ISSN 1664-302X, 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.

  • 33.
    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.

  • 34.
    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.

  • 35.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Reinthaler, Thomas
    University of Vienna, Austria.
    Herndl, Gerhard J.
    University of Vienna, Austria ; Royal Netherlands Institute for Sea Research (NIOZ), The Netherlands.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Major Effect of Hydrogen Peroxide on Bacterioplankton Metabolism in the Northeast Atlantic2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 4, article id e61051Article in journal (Refereed)
    Abstract [en]

    Reactive oxygen species such as hydrogen peroxide have the potential to alter metabolic rates of marine prokaryotes, ultimately impacting the cycling and bioavailability of nutrients and carbon. We studied the influence of H2O2 on prokaryotic heterotrophic production (PHP) and extracellular enzymatic activities (i.e., beta-glucosidase [BGase], leucine aminopeptidase [LAPase] and alkaline phosphatase [APase]) in the subtropical Atlantic. With increasing concentrations of H2O2 in the range of 100-1000 nM, LAPase, APase and BGase were reduced by up to 11, 23 and 62%, respectively, in the different water layers. Incubation experiments with subsurface waters revealed a strong inhibition of all measured enzymatic activities upon H2O2 amendments in the range of 10-500 nM after 24 h. H2O2 additions also reduced prokaryotic heterotrophic production by 36-100% compared to the rapid increases in production rates occurring in the unamended controls. Our results indicate that oxidative stress caused by H2O2 affects prokaryotic growth and hydrolysis of specific components of the organic matter pool. Thus, we suggest that oxidative stress may have important consequences on marine carbon and energy fluxes.

  • 36.
    Baltar, Federico
    et al.
    Univ Las Palmas Gran Canaria, Fac Ciencias Mar, Las Palmas Gran Canaria 35017, Spain.
    Sintes, Eva
    van Aken, Hendrik M.
    Gasol, Josep M.
    Arístegui, Javier
    Herndl, Gerhard J.
    Prokaryotic extracellular enzymatic activity in relation to biomass production and respiration in the meso- and bathypelagic waters of the (sub)tropical Atlantic2009In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 11, no 8, p. 1998-2014Article in journal (Refereed)
    Abstract [en]

    P>Prokaryotic extracellular enzymatic activity, abundance, heterotrophic production and respiration were determined in the meso- and bathypelagic (sub)tropical North Atlantic. While prokaryotic heterotrophic production (PHP) decreased from the lower euphotic layer to the bathypelagic waters by two orders of magnitude, prokaryotic abundance and cell-specific PHP decreased only by one order of magnitude. In contrast to cell-specific PHP, cell-specific extracellular enzymatic activity (alpha- and beta-glucosidase, leucine aminopeptidase, alkaline phosphatase) increased with depth as did cell-specific respiration rates. Cell-specific alkaline phosphatase activity increased from the intermediate water masses to the deep waters up to fivefold. Phosphate concentrations, however, varied only by a factor of two between the different water masses, indicating that phosphatase activity is not related to phosphate availability in the deep waters. Generally, cell-specific extracellular enzymatic activities were inversely related to cell-specific prokaryotic leucine incorporation. Thus, it is apparent that the utilization of deep ocean organic matter is linked to higher cell-specific extracellular enzymatic activity and respiration and lower cell-specific PHP than in surface waters. 

  • 37. Barber, I.
    et al.
    Svensson, P. A.
    Effects of experimental Schistocephalus solidus infections on growth, morphology and sexual development of female three-spined sticklebacks, Gasterosteus aculeatus2003In: Parasitology, ISSN 0031-1820, E-ISSN 1469-8161, Vol. 126, p. 359-367Article in journal (Refereed)
    Abstract [en]

    The use of naturally infected hosts in studies attempting to identify parasite-induced changes in host biology is problematical because it does not eliminate the possibility that infection may be a consequence, rather than a cause, of host trait variation. In addition, uncontrolled concomitant infections may confound results. In this study we experimentally infected individual laboratory-bred female three-spined sticklebacks Gasterosteus aculeatus L. with the pseudophyllidean cestode Schistocephalus solidus [Muller], and compared the morphology and growth patterns of infected females with sham-exposed controls over a 16-week period. Fish were fed a ration of 8% body weight per day. Non-invasive image analysis techniques allowed the growth of individual plerocercoids to be tracked in vivo throughout the course of infection, and patterns of host and parasite growth were determined. Females that developed infections diverged morphometrically from unexposed control females and exposed-uninfected females at 6 weeks post-infection, with the width of the body at the pectoral fins giving the earliest indication of infection success. When including the plerocercoid, infected females gained weight more quickly than controls, but when plerocercoid weight was removed this trend was reversed. There was no effect of infection on the increase in fish length. Plerocercoids grew at different rates in individual hosts, and exhibited measurable sustained weight increases of up to 10% per day. Final estimates of plerocercoid weight from morphometric analysis prior to autopsy were accurate to within +/-17% of actual plerocercoid weight. At autopsy, infected female sticklebacks had significantly lower perivisceral fat reserves but had developed significantly larger ovaries than controls. The results are discussed in relation to previous studies examining natural infections, and the value of utilizing experimental infections to examine ecological aspects of host-parasite interactions is discussed.

  • 38. Barber, I.
    et al.
    Walker, P.
    Svensson, P. A.
    Behavioural responses to simulated avian predation in female three spined sticklebacks the effect of experimental Schistocephalus solidus infections2004In: Behaviour, ISSN 0005-7959, E-ISSN 1568-539X, Vol. 141, p. 1425-1440Article in journal (Refereed)
    Abstract [en]

    Plerocercoid larvae of Schistocephalus solidus are common parasites of three-spined sticklebacks that require the ingestion of stickleback hosts by birds to complete their life cycle. Amongst wild-caught sticklebacks, infection is associated with a reduction in antipredator behaviour; however, to date no study has examined the escape responses of experimentally infected sticklebacks, and thus assigning causality remains difficult. Here, we compare aspects of the antipredator behaviour of five experimentally infected female sticklebacks with shamexposed controls over a 16 post-exposure week period. During weeks 1-7 post-exposure, the escape responses of infected fish did not differ significantly from those of sham-exposed fish. However, over weeks 9-15, when infected fish had developed plerocercoids of >50 mg—the size at which they become infective to birds —a lower proportion of infected fish performed directional responses and reached cover within 2 s of the strike. Infected fish also performed a lower frequency of ‘staggered dashes’, and a higher frequency of ‘slow swims’, than shamexposed fish over weeks 9-15. Amongst sham-exposed fish, re-emergence from cover was uncommon throughout the study, but infected fish regularly left cover during weeks 9-15. Our results support those of previous studies examining behavioural change in naturally infected fish and, although other explanations remain possible, our finding that behaviour change in experimentally-infected fish is limited to hosts harbouring single infective parasites provides further evidence that the behaviour changes may be parasite adaptations.

  • 39.
    Barshep, Yahkat
    et al.
    A.P. Leventis Ornithological Research Institute, Nigeria.
    Ottosson, Ulf
    A.P. Leventis Ornithological Research Institute, Nigeria.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hulme, Mark
    British Trust for Ornithology, UK.
    Non-breeding ecology of the Whinchat Saxicola rubetra in Nigeria2012In: Ornis Svecica, ISSN 1102-6812, Vol. 22, p. 25-32Article in journal (Refereed)
    Abstract [en]

    This study on the non-breeding ecology of the Whinchat Saxicola rubetra was conducted in central Nigeria from February through April. The core site was at Gwafan (N09°53', E08°57'), an open scrubland located 10 km east of the city of Jos. The density of Whinchats at Gwafan was 0.58 individuals/ha, almost three times the overall density around Jos. Time budget observations of colour banded Whinchats, including six birds fitted with radio-transmitters, showed that they spent 80% of their time perching, 11% foraging, 7% preening, and 2% flying. The main method of catching insects was a swoop to the ground. There was no change in perching, preening or flying time but the time some Whinchats spent foraging increased towards the end of the study period. GPS positions of individuals showed that all birds held clearly demarcated territories and defended them against neighbours. Aggressive interactions were also recorded between Whinchats and other bird species. Three birds colour-ringed in 2006 returned to the study site in 2007 and one occupied almost the same territory, indicating site fidelity.

  • 40. Beja, Oded
    et al.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Spudich, John L.
    Proteorhodopsins: widespread microbial light-driven proton pumps2013In: Encyclopedia of Biodiversity / [ed] Levin S.A., Waltham, MA: Academic Press, 2013, 2:nd edition, vol. 2, p. 280-285Chapter in book (Refereed)
    Abstract [en]

    Proteorhodopsins (PRs) are membrane-embedded, retinal-containing proteins that function as light-driven proton pumps. Since their discovery in 2000 in uncultured marine bacteria, PRs have been detected in numerous bacteria, archaea, and microbial eukarya. PRs have now been detected in diverse habitats, including marine, brackish, and freshwater environments; leaf surfaces; and soil crusts. Their widespread distribution and relatively simple single-molecule design suggests them as the earliest light-energy transducing proteins to have evolved. Currently, PRs represent the simplest biological means to convert light energy into chemical energy.

  • 41. Bellebaum, Jochen
    et al.
    Larsson, Kjell
    Kube, Jan
    Research on Sea Ducks in the Baltic Sea2012Other (Other academic)
  • 42.
    Bengtsson, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Stopover Ecology of Mallards: Where, when and how to do what?2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the northern hemisphere and a model species in ecology and harvest management. Migration is a crucial life stage for many birds and understanding the drivers of migration has important implications for conservation biology and assessment of animal population responses to global changes. Furthermore, mallard migration is a fundamental determinant of the epidemiology of many diseases of major relevance for both animal and human health. For example, it is the reservoir host for influenza A viruses (IAV), a widespread zoonosis causing mortality and economic damage. Improved knowledge of mallard behaviour during migration and the impacts of infection in mallards is needed to determine the role of wild birds in global IAV dynamics.

    This thesis focuses on mallard stopover ecology, an explicitly important part of the annual life cycle that is not well understood. The study area was southern Öland, SE Sweden, where mallard stopover behaviour was scrutinized by a combination of telemetry and ringing data analyses. Specifically, habitat preferences, movements, and emigration decisions were studied in-depth. Potential effects of low pathogenic avian influenza (LPAIV) infection on movement parameters were also investigated. Radio-tracking revealed that stopover mallards adhered to a strict diel pattern, in which they spent the days resting along the coast, visited crop fields at dawn and dusk, and foraged on inland water bodies during the darkest night hours. Notably, the importance of residual maize, as well as small ephemeral wetlands on the unique alvar steppe habitat that predominates on Öland, was previously unknown. LPAIV infection status did not affect movement behaviour, highlighting the possible risk of spread of IAV from wild mallards to poultry along the migratory flyway. Through capture-mark-recapture modelling, it was confirmed that weather, particularly wind direction, was the most important determinant of departure from the stopover site. In contrast, the body condition of departing mallards was less crucial. Taken together, the research presented in this thesis contributes to improved knowledge about mallard stopover ecology and its role in LPAIV disease dynamics.

  • 43.
    Bengtsson, Daniel
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Andersson, Stina
    Ottenby Bird Observatory.
    Hellström, Magnus
    Ottenby Bird Observatory.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Age and sex determination of mallards Anas platyrhynchos in autumn2016In: Ornis Svecica, ISSN 1102-6812, Vol. 26, p. 61-81Article in journal (Refereed)
    Abstract [en]

    The mallard is a well-known and important species in migration ecology, game management,and epidemiology. Males and females are generally easily told apart, whereas ageing isproblematic, due to individual timing of the moult cycle and lack of easily defined agecriteria. From examination and photographic documentation of mallards caught within a longtermringing program at Ottenby Bird Observatory (56°12′N, 16°24′E), we describe ninecharacters of plumage and bare parts to be used for ageing mallards in autumn. The reliabilityof these characters was tested by letting experienced bird ringers determine putative age ofbirds from photos. Age determination from any single character proved to be uncertain, as therate of correctly assigned mallard photos of each character was in the range of 51-85% formales and 48-89% for females. For both sexes, the lowest figure represented post-humeralsand the highest represented tertials. Rectrices, tertial coverts, and greater coverts also hadreasonably high scores (71-85%). With all characters at hand, 91% of the males and 95% ofthe females were correctly identified to age. As young mallards, with the progress of prebreedingmoult (completed from October onwards), acquire tail and tertials identical to adults,untypical individuals are better not assigned to an age category.

  • 44.
    Bengtsson, Daniel
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Avril, Alexis
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gunnarsson, Gunnar
    Kristianstad University.
    Elmberg, Johan
    Kristianstad University.
    Söderquist, Pär
    Kristianstad University.
    Norevik, Gabriel
    Ottenby Bird Observatory.
    Tolf, Conny
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Safi, Kamran
    Max Planck Institute for Ornitholology, Germany ; University of Konstanz, Germany.
    Fiedler, Wolfgang
    Max Planck Institute for Ornitholology, Germany ; University of Konstanz, Germany.
    Wikelski, Martin
    Max Planck Institute for Ornitholology, Germany ; University of Konstanz, Germany.
    Olsen, Björn
    Uppsala University.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Movements, Home-Range Size and Habitat Selection of Mallards during Autumn Migration2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 6, article id e100764Article in journal (Refereed)
    Abstract [en]

    The mallard (Anas platyrhynchos) is a focal species in game management, epidemiology and ornithology, but comparably little research has focused on the ecology of the migration seasons. We studied habitat use, time-budgets, home-range sizes, habitat selection, and movements based on spatial data collected with GPS devices attached to wild mallards trapped at an autumn stopover site in the Northwest European flyway. Sixteen individuals (13 males, 3 females) were followed for 15-38 days in October to December 2010. Forty-nine percent (SD = 8.4%) of the ducks' total time, and 85% of the day-time (SD = 28.3%), was spent at sheltered reefs and bays on the coast. Two ducks used ponds, rather than coast, as day-roosts instead. Mallards spent most of the night (76% of total time, SD = 15.8%) on wetlands, mainly on alvar steppe, or in various flooded areas (e.g. coastal meadows). Crop fields with maize were also selectively utilized. Movements between roosting and foraging areas mainly took place at dawn and dusk, and the home-ranges observed in our study are among the largest ever documented for mallards (mean = 6,859 ha; SD = 5,872 ha). This study provides insights into relatively unknown aspects of mallard ecology. The fact that autumn-staging migratory mallards have a well-developed diel activity pattern tightly linked to the use of specific habitats has implications for wetland management, hunting and conservation, as well as for the epidemiology of diseases shared between wildlife and domestic animals.

  • 45.
    Bengtsson, Daniel
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Safi, Kamran
    Max Planck Institute for Ornithology, Germany ; University of Konstanz, Germany.
    Avril, Alexis
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fiedler, Wolfgang
    Max Planck Institute for Ornithology, Germany ; University of Konstanz, Germany.
    Wikelski, Martin
    Max Planck Institute for Ornithology, Germany ; University of Konstanz, Germany.
    Gunnarsson, Gunnar
    Kristianstad University.
    Elmberg, Johan
    Kristianstad University.
    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.
    Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host?2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 2, p. 1-11, article id UNSP 150633Article in journal (Refereed)
    Abstract [en]

    The last decade has seen a surge in research on avian influenza A viruses (IAVs), in part fuelled by the emergence, spread and potential zoonotic importance of highly pathogenic virus subtypes. The mallard (Anas platyrhynchos) is the most numerous and widespread dabbling duck in the world, and one of the most important natural hosts for studying IAV transmission dynamics. In order to predict the likelihood of IAV transmission between individual ducks and to other hosts, as well as between geographical regions, it is important to understand how IAV infection affects the host. In this study, we analysed the movements of 40 mallards equipped with GPS transmitters and three-dimensional accelerometers, of which 20 were naturally infected with low pathogenic avian influenza virus (LPAIV), at a major stopover site in the Northwest European flyway. Movements differed substantially between day and night, as well as between mallards returning to the capture site and those feeding in natural habitats. However, movement patterns did not differ between LPAIV infected and uninfected birds. Hence, LPAIV infection probably does not affect mallard movements during stopover, with high possibility of virus spread along the migration route as a consequence.

  • 46.
    Bengtsson, Daniel
    et al.
    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.
    Avril, Alexis
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tailwind better than full tank? How weather and body condition affect departure decision in an autumn-staging migrantIn: Article in journal (Refereed)
  • 47.
    Bengtsson, Marie
    et al.
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Boutitie, Anne
    SUAMME, Mas de Saporta, Lattes, France.
    Jósvai, Julia
    Plant Protection Institute MTA ATK, Budapest, Hungary.
    Toth, Miklos
    Plant Protection Institute MTA ATK, Budapest, Hungary.
    Andreadis, Stefanos
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Rauscher, Stefan
    Swiss Federal Research Station, Wädenswil, Switzerland.
    Unelius, C. Rikard
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Witzgall, Peter
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Pheromone races of Cydia splendana (Lepidoptera, Tortricidae) overlap in host plant association and geographic distribution2014In: Frontiers in Ecology and Evolution, E-ISSN 2296-701X, Vol. 2, p. Article ID: 46-Article in journal (Refereed)
    Abstract [en]

    Identification of the sex pheromone of Cydia splendana (Lepidoptera, Tortricidae) bypheromone gland analysis followed by field trapping with synthetic compounds showsthe occurrence of two pheromone races. Acorn moth females from Sweden, whereoak Quercus robur is the only host plant, use a blend of the E,Z and E,E isomers of8,10-dodecadien-1-yl acetate. In Central and Southern Europe, where C. splendana feedson chestnut Castanea sativa and several species of oak, males respond to another isomerblend, E,E and Z,E. The distribution of the two pheromone races of C. splendana overlapsin Northern France, where they share oak as plant host. Differences in sex communicationsignals between these populations of C. splendana corroborate the role of specific materecognition in speciation events.

  • 48.
    Bennett, N. C.
    et al.
    Univ Pretoria, South Africa.
    Ganswindt, A.
    Univ Pretoria, South Africa.
    Ganswindt, S. B.
    Univ Pretoria, South Africa.
    Jarvis, J. U. M.
    Univ Cape Town, South Africa.
    Zöttl, Markus
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Cambridge, UK.
    Faulkes, C. G.
    Queen Mary Univ London, UK.
    Evidence for contrasting roles for prolactin in eusocial naked mole-rats, Heterocephalus glaber and Damaraland mole-rats, Fukomys damarensis2018In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 14, no 5, article id 20180150Article in journal (Refereed)
    Abstract [en]

    Elevated prolactin (PRL) has been associated with the expression of social and cooperative behaviours in a number of vertebrate species, as well as suppression of reproduction. As social mole-rats exhibit both of these traits, PRL is a prime candidate in mediating their social phenotype. While naked and Damaraland mole-rats (NMRs and DMRs) have evolved eusociality independently within their family, both species exhibit an extreme skew in lifetime reproductive success, with breeding restricted to a single female and one or two males. Non-breeding NMRs of both sexes are physiologically inhibited from reproducing, while in DMRs only the non-breeding females are physiologically suppressed. Newly emerging work has implicated the dopamine system and PRL as a component in socially induced reproductive suppression and eusociality in NMR, but the DMR remains unstudied in this context. To investigate evolutionary convergence in the role of PRL in shaping African mole-rat eusociality, we determined plasma PRL concentrations in breeders and non-breeders of both sexes, comparing DMRs with NMRs. Among samples from non-breeding NMRs 80% had detectable plasma PRL concentrations. As a benchmark, these often (37%) exceeding those considered clinically hyperprolactinaemic (25 ng ml(-1)) in humans: mean +/- s.e.m.: 34.81 +/- 5.87 ngml(-1); range 0.00-330.30 ng ml(-1). Conversely, 85% of non-breeding DMR samples had undetectable values and none had concentrations above 25 ng ml(-1): 0.71 +/- 0.38 ng ml(-1); 0.00-23.87 ngml(-1). Breeders in both species had the expected variance in plasma PRL concentrations as part of normal reproductive function, with lactating queens having significantly higher values. These results suggest that while elevated PRL in non-breeders is implicated in NMR eusociality, this may not be the case in DMRs, and suggests a lack of evolutionary convergence in the proximate control of the social phenotype in these mole-rats.

  • 49.
    Berggren, Hanna
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Nordahl, Oscar
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tibblin, Petter
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Larsson, Per
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Forsman, Anders
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Testing for local adaptation to spawning habitat in sympatric subpopulations of northern pike by reciprocal translocation of embryos2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 5, article id e0154488Article in journal (Refereed)
    Abstract [en]

    We tested for local adaption in early life-history traits by performing a reciprocal translocation experiment with approximately 2500 embryos of pike (Esox lucius) divided in paired split-family batches. The experiment indicated local adaptation in one of the two subpopulations manifested as enhanced hatching success of eggs in the native habitat, both when compared to siblings transferred to a non-native habitat, and when compared to immigrant genotypes from the other subpopulation. Gene-by-environment effects on viability of eggs and larvae were evident in both subpopulations, showing that there existed genetic variation allowing for evolutionary responses to divergent selection, and indicating a capacity for plastic responses to environmental change. Next, we tested for differences in female life-history traits. Results uncovered that females from one population invested more resources into reproduction and also produced more (but smaller) eggs in relation to their body size compared to females from the other population. We suggest that these females have adjusted their reproductive strategies as a counter-adaptation because a high amount of sedimentation on the eggs in that subpopulations spawning habitat might benefit smaller eggs. Collectively, our findings point to adaptive divergence among sympatric subpopulations that are physically separated only for a short period during reproduction and early development – which is rare. These results illustrate how combinations of translocation experiments and field studies of life-history traits might infer about local adaptation and evolutionary divergence among populations. Local adaptations in subdivided populations are important to consider in management and conservation of biodiversity, because they may otherwise be negatively affected by harvesting, supplementation, and reintroduction efforts targeted at endangered populations.

  • 50.
    Bergström, Kristofer
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Impact of Using Macroalgae from the Baltic Sea in Biogas Production: A Review with Special Emphasis on Heavy Metals2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    A consequence of eutrophication in the Baltic Sea is growth of algae that accumulates in the coastal areas and beaches. Dense algal mats may cause anoxia or hypoxia and greatly reduce the recreational value of the area. Algae also functions as hyper accumulators of heavy metals and their metal levels may become toxic to higher trophic levels. The project Wetlands, Algae and Biogas (WAB) aims at removing algal beach cast for commercial use in biogas production and further use of the fermentation residues as fertilizer. Collection of algae would remove both nutrients and heavy metals from the Baltic Sea but leave us with large amounts of algae containing heavy metals. A concern for the biogas production based on these Baltic algae is the effects from the heavy metals, during fermentation, in the residues and the use of them as fertilizer. A literature review shows that the levels of heavy metals should not inhibit the biogas production but during the fermentation there is a loss of (48%) biological material and the metals are concentrated in the residues. Samples of algae from Trelleborg (SE) show higher concentrations of cadmium (Cd) than algae from Poland (PL). The Swedish residues border or surpass the legislative amount of heavy metals that are allowed to be applied to arable land in Sweden. This is both due to the higher concentrations of heavy metals and the differences between European and Swedish legislation. To use the residues as fertilizer detoxification is required, mainly for Cd in Sweden. There are effective methods, chemicals and ion exchangers (70-80%), for removing heavy metals from organic leachate. But these methods lack testing on a large scale, the costs and the environmental aspect of these methods on tons of algae per year are unknown. Co-fermentation with a suitable substrate would dilute the heavy metal concentration and could reduce possible problems such as hydrogen sulfide accumulation in the biogas. Another possible pathway for dealing with the heavy metal rich residues is as fertilizer for non-food crops such as the biofuel species willow (Salix). Willow is a fast growing tree that is a known accumulator of heavy metals and can be used as a remediation for contaminated soil. Based on the metal concentrations and respective legislation, estimations of 20 000 ha of willow for Trelleborg and 400 ha for Sopot beach (PL) is needed to process harvested algae. 

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