An event of releasing untreated effluent caused serious decreases in surface seawater pH from 8.1 to lower than 7.5 in seven years and increased back to prior levels after 15 years. It gives us a rare natural experiment to examine the impacts of decreases in pH on the marine plankton communities (phytoplanktons, zooplanktons, shrimp larvae, crab larvae, fish eggs, and larvae) in the natural environment. Observed decreases in pH had a nonlinear effect ubiquitous on all plankton groups, leading to a reduction of approximately 50 % in their density and abundance compared to the level at pH 8.1. Non-linear responses of planktons implied the existence of specific groups more robust to decreases in pH. As pH bounced back to normal levels, the density and abundance of the plankton communities also recovered, further indicating that the negative impacts of decreases in pH on the marine plankton communities were reversible.

中文翻译：

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污水 pH 值的降低对沿海浮游生物群落产生了毁灭性但可逆的影响


排放未经处理的污水事件导致表层海水 pH 值在 7 年内从 8.1 严重下降到 7.5 以下，并在 15 年后恢复到以前的水平。它为我们提供了一个罕见的自然实验，以检查 pH 值降低对自然环境中海洋浮游生物群落（浮游植物、浮游动物、虾幼虫、蟹幼虫、鱼卵和幼虫）的影响。观察到的 pH 值降低在所有浮游生物群中都具有无处不在的非线性效应，导致与 pH 值 8.1 时的水平相比，它们的密度和丰度降低了约 50%。浮游生物的非线性响应意味着存在对 pH 值降低更稳健的特定组。随着 pH 值反弹至正常水平，浮游生物群落的密度和丰度也恢复，进一步表明 pH 值降低对海洋浮游生物群落的负面影响是可逆的。