Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins.
Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins.
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DOI：
10.3390/toxins9020064
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发表时间：
2017-02-11
期刊：
影响因子：
4.2
通讯作者：
Faassen E
中科院分区：
文献类型：
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作者：
Lürling M;van Oosterhout F;Faassen E
富营养化和变暖是蓝藻华的关键驱动因素，但它们对微囊藻毒素（MC）浓度的综合影响研究较少。我们测试了一个假设，即变暖促进了天然浮游生物群落中蓝藻的丰度，富营养化提高了蓝藻的生物量和MC浓度。我们在正常、高温和极端温度（即20、25和30°C）下对富营养化池塘中的天然林分进行孵育，并添加或不添加额外的营养物质（富营养化），模拟气候变化下预计的夏季风暴的脉冲。富营养化使藻类和蓝藻生物量分别增加了26倍和8倍，MC浓度增加了24倍。这种效应随着温度的升高而增强，在25°C时MC浓度增加了45倍，蓝藻叶绿素-a增加了11倍，真核藻类叶绿素-a增加了25倍。30℃时，MC浓度升高42倍，其中蓝藻叶绿素-a升高17倍，真核藻类叶绿素-a升高24倍。相比之下，单独变暖并不能产生更多的蓝藻或MCs，因为原地群落已经耗尽了可用的营养池。在两株铜绿微囊藻的对照实验中证实，在营养丰富的条件下，温度越高，产MC细胞的MC值越低。然而，在温度升高和养分处理下，MC浓度远高于单独增温处理，这主要是由于生物量的提高、对n的模仿以及微囊藻等潜在MC生产者的促进。这项研究举例说明了富营养化城市水域对未来夏季气候变化影响的脆弱性，这些影响可能会加剧蓝藻的滋扰。
Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC) concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial biomass and MC concentrations. We incubated natural seston from a eutrophic pond under normal, high, and extreme temperatures (i.e., 20, 25, and 30 °C) with and without additional nutrients added (eutrophication) mimicking a pulse as could be expected from projected summer storms under climate change. Eutrophication increased algal- and cyanobacterial biomass by 26 and 8 times, respectively, and led to 24 times higher MC concentrations. This effect was augmented with higher temperatures leading to 45 times higher MC concentrations at 25 °C, with 11 times more cyanobacterial chlorophyll-a and 25 times more eukaryote algal chlorophyll-a. At 30 °C, MC concentrations were 42 times higher, with cyanobacterial chlorophyll-a being 17 times and eukaryote algal chlorophyll-a being 24 times higher. In contrast, warming alone did not yield more cyanobacteria or MCs, because the in situ community had already depleted the available nutrient pool. MC per potential MC producing cell declined at higher temperatures under nutrient enrichments, which was confirmed by a controlled experiment with two laboratory strains of Microcystis aeruginosa. Nevertheless, MC concentrations were much higher at the increased temperature and nutrient treatment than under warming alone due to strongly promoted biomass, lifting N-imitation and promotion of potential MC producers like Microcystis. This study exemplifies the vulnerability of eutrophic urban waters to predicted future summer climate change effects that might aggravate cyanobacterial nuisance.