Ramos-Rodríguez Eloísa, Pérez-Martínez Carmen, Conde-Porcuna José María
Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
Instituto del Agua, Universidad de Granada, 18003 Granada, Spain.
Biology (Basel). 2022 Oct 20;11(10):1539. doi: 10.3390/biology11101539.
Calcium (Ca) is an important driver of community structure in freshwaters. We examined the combined effects of increased temperatures and variations in food quantity on the tolerance to low Ca of Daphnia pulex. The aim was to predict the impact of climate warming on this keystone zooplanktonic species in cold-climate lakes. We conducted a factorial life-history experiment in a clone of North American Daphnia cf. pulex to analyse the interaction effects of a temperature increase (17.5 °C−21 °C) within their physiological preferred range and expected by climate warming over the next few decades and a narrow Ca gradient (0.25−1.74 mg Ca L−1) under stressful vs. abundant food conditions. We found a striking positive synergistic effect of Ca and temperature on D. pulex reproduction at high food conditions. Although the increase in temperature to 21 °C greatly reduced survival, high energy allocation to reproduction at high food levels allowed the population to succeed in poor Ca (<0.25 mg Ca L−1). Results suggest that climate warming and higher food availability will make the populations of many cold and Ca-limited lakes more tolerant to low Ca levels with higher growth population rates, thereby altering zooplanktonic community structures and inducing potential cascading effects on the food web.
钙（Ca）是淡水群落结构的重要驱动因素。我们研究了温度升高和食物量变化对大型溞耐低钙能力的综合影响。目的是预测气候变暖对寒冷气候湖泊中这种关键浮游动物物种的影响。我们对北美大型溞的一个克隆体进行了析因生活史实验，以分析在其生理适宜范围内且预计未来几十年气候变暖会出现的温度升高（17.5℃至21℃），以及在食物压力大与充足的条件下狭窄的钙梯度（0.25 - 1.74毫克钙/升）之间的相互作用效应。我们发现，在食物充足的条件下，钙和温度对大型溞繁殖有显著的正协同效应。尽管温度升高到21℃会大大降低存活率，但在食物水平高时对繁殖的高能量分配使种群在低钙（<0.25毫克钙/升）环境中得以成功繁衍。结果表明，气候变暖和更高的食物可利用性将使许多寒冷且受钙限制的湖泊中的种群对低钙水平更具耐受性，种群增长率更高，从而改变浮游动物群落结构，并对食物网引发潜在的级联效应。
