Nutrients and not temperature are the key drivers for cyanobacterial biomass in the AmericasShow others and affiliations
2023 (English)In: Harmful Algae, ISSN 1568-9883, E-ISSN 1878-1470, Vol. 121, article id 102367Article in journal (Refereed) Published
Abstract [en]
Cyanobacterial blooms imperil the use of freshwater around the globe and present challenges for water man-agement. Studies have suggested that blooms are trigged by high temperatures and nutrient concentrations. While the roles of nitrogen and phosphorus have long been debated, cyanobacterial dominance in phytoplankton has widely been associated with climate warming. However, studies at large geographical scales, covering diverse climate regions and lake depths, are still needed to clarify the drivers of cyanobacterial success. Here, we analyzed data from 464 lakes covering a 14,000 km north-south gradient in the Americas and three lake depth categories. We show that there were no clear trends in cyanobacterial biomass (as biovolume) along latitude or climate gradients, with the exception of lower biomass in polar climates. Phosphorus was the primary resource explaining cyanobacterial biomass in the Americas, while nitrogen was also significant but particularly relevant in very shallow lakes (< 3 m depth). Despite the assessed climatic gradient water temperature was only weakly related to cyanobacterial biomass, suggesting it is overemphasized in current discussions. Depth was critical for predicting cyanobacterial biomass, and shallow lakes proved more vulnerable to eutrophication. Among other variables analyzed, only pH was significantly related to cyanobacteria biomass, likely due to a biologically mediated positive feedback under high nutrient conditions. Solutions toward managing harmful cyanobacteria should thus consider lake morphometric characteristics and emphasize nutrient control, independently of tem-perature gradients, since local factors are more critical - and more amenable to controls - than global external forces.
Place, publisher, year, edition, pages
Elsevier, 2023. Vol. 121, article id 102367
Keywords [en]
Eutrophication, Blooms, Global gradients, Freshwater, Climate change
National Category
Ecology
Research subject
Natural Science, Ecology
Identifiers
URN: urn:nbn:se:lnu:diva-118841DOI: 10.1016/j.hal.2022.102367ISI: 000903524800003PubMedID: 36639186Scopus ID: 2-s2.0-85144300405OAI: oai:DiVA.org:lnu-118841DiVA, id: diva2:1732161
2023-01-302023-01-302023-05-31Bibliographically approved