The construction of drainage canals in the upper stretch of the Salado River has caused the input of salty waters into the basin, with unexplored consequences on zooplankton dynamics and reproduction. To determine the consequences of those anthropic interventions, zooplankton samples were taken under four hydrologic conditions (high water, mean flows, low flows, very low flows) in the canals and the river watercourse. Environmental variables were measured in situ (pH, temperature, conductivity, turbidity, flow velocity, water level, dissolved-oxygen concentration) and in the laboratory (chlorophyll a , nutrients). A total of 166 zooplankton taxa was identified, among which rotifers and ciliates were the most diverse and abundant. A redundancy analysis indicated temperature, conductivity, and water discharge to be the main constraints to zooplankton development. Accordingly, abundance peaks were recorded during mean and low flows in the spring and summer, and minimum values during high water (autumn–winter floodings). The dominant species, Brachionus plicatilis s.l. , recorded outstanding densities at ca. 34,800 ind L –1 —that figure representing a worldwide novelty—during low flows in the canals and at the river downstream site. The wetlands and shallow lakes in the study area acted as sources of inocula for the river, increasing the total abundance of zooplankton, gravid females, nauplii, copepodites, juveniles, and total number of eggs being carried at the second river site downstream from the canals’ discharges. The presence of diverse habitats coupled with the alternation of hydrologic conditions have resulted in the development of a very rich, complex zooplankton community.

中文翻译：

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Salado-River 盆地（阿根廷布宜诺斯艾利斯）的浮游动物种群动态与水力工程和由此产生的湿地功能有关

萨拉多河上游排水渠的建设导致咸水流入流域，对浮游动物的动态和繁殖产生了未经探索的影响。为了确定这些人为干预的后果，在运河和河道中的四种水文条件（高水位、平均流量、低流量、极低流量）下采集了浮游动物样本。环境变量在原位（pH、温度、电导率、浊度、流速、水位、溶解氧浓度）和实验室（叶绿素a、营养素）中测量。共鉴定出166个浮游动物类群，其中轮虫和纤毛虫种类最多，数量最多。冗余分析表明温度、电导率、排水是浮游动物发育的主要制约因素。因此，在春季和夏季的平均和低流量期间记录了丰度峰值，而在高水位（秋冬季洪水）期间记录了最小值。优势种 Brachionus plicatilis sl 记录了大约 10 年的突出密度。在运河和河流下游站点的低流量期间，34,800 ind L –1——这个数字代表了世界范围内的新奇事物。研究区的湿地和浅湖是河流的接种源，增加了运河下游第二个河流站点的浮游动物、妊娠雌性、无节幼体、桡足类、幼体和卵总数的总丰度' 放电。