| 作者： |
Yang, Yalan; Wang, Huan; Yan, Shuwen; Wang, Tao; Zhang, Peiyu; Zhang, Huan; Wang, Hongxia; Hansson, Lars-Anders; Xu, Jun |
| 论文摘要： |
Heatwaves and eutrophication interactivelyincreased thebiomass of Microcystis and production of toxins,indicating that nutrient loading needs to be reduced under climatechange. Climate change and eutrophication are two environmentalthreatsthat can alter the structure of freshwater ecosystems and their servicefunctions, but we know little about how ecosystem structure and functionwill evolve in future scenarios of climate warming. Therefore, wecreated different experimental climate scenarios, including present-dayconditions, a 3.0 & DEG;C increase in mean temperature, and a heatwavesscenario (i.e., an increase in temperature variability) to assessthe effects of climate change on phytoplankton communities under simultaneousstress from eutrophication and herbicides. We show that the effectsof climate warming, particularly heatwaves, are associated with elevatedcyanobacterial abundances and toxin production, driven by a changefrom mainly nontoxic to toxic Microcystis spp. Thereason for higher cyanobacterial toxin concentrations is likely anincrease in abundances because under the dual pressures of climatewarming and eutrophication individual Microcystis toxin-producing ability decreased. Eutrophication and higher temperaturessignificantly increased the biomass of Microcystis, leading to an increase in the cyanobacterial toxin concentrations.In contrast, warming alone did not produce higher cyanobacterial abundancesor cyanobacterial toxin concentrations likely due to the depletionof the available nutrient pool. Similarly, the herbicide glyphosatealone did not affect abundances of any phytoplankton taxa. In thecase of nutrient enrichment, cyanobacterial toxin concentrations weremuch higher than under warming alone due to a strong boost in biomassof potential cyanobacterial toxin producers. From a broader perspectiveour study shows that in a future warmer climate, nutrient loadinghas to be reduced if toxic cyanobacterial dominance is to be controlled. |
