In recent years, low-salinity events characterized by high temperatures (18–23 °C) and low-salinity waters (20‰–22‰) have increased during late spring and summer, when many marine invertebrate larvae are developing. The present study examines the effects of low-salinity events on particle ingestion for larvae of two echinoderm species, the sea star Pisaster ochraceus and the sand dollar Dendraster excentricus. Larvae were exposed to high temperatures and low salinities for 24 hours, followed by feeding on the alga Isochrysis galbana in high or low salinity for another 10 minutes. Exposing Pisaster larvae to high temperatures and low salinities, followed by feeding in low salinity, did not impair ingestion rates. In fact, these larvae ingested particles at similar and sometimes higher rates than those in the controls. In sharp contrast, a 24-hour exposure to a high temperature and low salinity, followed by continued exposure to low salinity to feed, led to a decrease in the number of particles ingested by 8-arm Dendraster larvae. Larvae of both species captured very few particles when returned to 30‰ after a low-salinity event, indicating that continuous interruption of larval feeding by low-salinity events during development could be deleterious. Sand dollar larvae may have responded negatively to low-salinity events in our experiments because they are found in protected bays, where they may seldom experience these events.

中文翻译：

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温度和盐度的偶发波动可能会增加 Pisaster ochraceus（Asteroidea）的摄食，但不会增加 Dendraster excentricus（Echinoidea）幼虫的摄食

近年来，以高温（18～23℃）和低盐度水域（20‰～22‰）为特征的低盐度事件在春末和夏季有所增加，许多海洋无脊椎动物幼虫正在发育。本研究调查了低盐度事件对两种棘皮动物幼虫（海星Pisaster ochraceus和沙元Dendraster excentricus）的颗粒摄取的影响。幼虫暴露于高温和低盐度下 24 小时，然后在高盐度或低盐度下以藻类等鞭金藻为食10 分钟。揭露Pisaster幼虫适应高温和低盐度，然后在低盐度下觅食，不会影响摄食率。事实上，这些幼虫以与对照组相似的速度摄取颗粒，有时甚至更高。与此形成鲜明对比的是，24 小时暴露在高温低盐度环境中，随后继续暴露在低盐度环境中觅食，导致 8 臂Dendraster摄入的颗粒数量减少幼虫。两种物种的幼虫在低盐度事件后恢复到 30‰ 时捕获的颗粒很少，这表明在发育过程中低盐度事件持续中断幼虫摄食可能是有害的。在我们的实验中，沙钱幼虫可能对低盐度事件产生负面反应，因为它们被发现在受保护的海湾中，在那里它们可能很少经历这些事件。