Variability of phytoplankton biomass in a lowland river: Response to climate conditions
Variability of phytoplankton biomass in a lowland river: Response to climate conditions
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DOI：
10.1016/j.limno.2010.08.002
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发表时间：
2011-09
期刊：
影响因子：
1.7
通讯作者：
B. Desortová;P. Punčochář
中科院分区：
文献类型：
--
作者：
B. Desortová;P. Punčochář
结果提出了浮游植物组合进行了深入的研究，在Berounka河与伏尔塔瓦河（捷克共和国）在2002年至2007年期间的汇合处以上。分析了浮游植物发育的年际变化（基于高频率采样）及其与水文条件和主要营养盐浓度的关系。在1996-2007年期间，观察到营养物浓度显著下降。全磷年平均值从0.43mgL-1下降到0.16mgL-1，N-NO3年平均值从4.6mgL-1下降到1.5mgL-1，N-NH 4年平均值从1.9mgL-1下降到0.04mgL-1。尽管如此，浮游植物生物量仍然保持在较高水平。同期叶绿素a的季节平均值为51.0μgL− 1至116.8μgL− 1。浮游植物生物量及其发展模式与流速的关系明显强于与营养盐浓度的关系。根据2002-2007年季节的月平均值，发现叶绿素a与流速的显著降低关系（R2 =0.384，P <0.001）和叶绿素a与水温的显著增加关系（R2=0.359，P<0.001）。所获得的结果表明，浮游植物生物量显著增加，其在水道中的出现率也会增加，这是由于预测的气候变化的后果（即夏季干旱发生率较高，降水量较低，同时流速大幅下降，空气和水温升高），正如捷克共和国领土的相应情景所述。区域气候模式HIRHAM和RCAO以及排放情景SRES的模拟表明，在2071-2100年的情景期间，Berounka河的气温上升2.5-5°C，降水量减少6-25%，流量减少14-43%。
The results are presented of an intensive study of phytoplankton assemblage carried out in the Berounka River above its confluence with the Vltava River (Czech Republic) in the period 2002–2007. The annual and interannual changes of phytoplankton development (based on high frequency of sampling) and their relation to hydrological conditions and concentrations of main nutrients are analysed. A marked decline of nutrient concentrations was observed during the period 1996–2007. The annual mean values of total P decreased from 0.43mgL−1to 0.16mgL−1, those of N-NO3from 4.6mgL−1to 1.5mgL−1and N-NH4from 1.9mgL−1to 0.04mgL−1. Despite this, the phytoplankton biomass remained at a high level. The seasonal mean values of chlorophyll-a ranged from 51.0μgL−1to 116.8μgL−1in the same time period. An obviously stronger relationship was found of the phytoplankton biomass and pattern of its development to the variation of flow rates than to the existing level of nutrient concentrations. A significantly decreasing relationship (R2=0.384, P<0.001) of chlorophyll-a to flow rates and a significantly increasing relationship (R2=0.359, P<0.001) of chlorophyll-a to water temperatures were found, based on monthly mean values for the seasonal period 2002–2007. The results obtained indicate a remarkable increase of phytoplankton biomass and its prolongated occurrence in watercourses, which can be expected due to the consequences of the predicted climate change (i.e. higher occurrence of summer droughts and low precipitation amounts accompanied by a substantial drop of flow rates, increase of air and water temperatures), as described in the respective scenarios for the territory of the Czech Republic. Simulations by the regional climate models HIRHAM and RCAO and emission scenario SRES indicated the increase of air temperature by 2.5–5°C, decrease of precipitation amount by 6–25% and decline of flows by 14–43% in the Berounka River for the scenario period 2071–2100.