Porites Coral on a Remote Reef Reveal Marine Phosphorus Biogeochemical Cycling Following Artificial Disturbance
Porites Coral on a Remote Reef Reveal Marine Phosphorus Biogeochemical Cycling Following Artificial Disturbance
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DOI：
10.1029/2020jc016388
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发表时间：
2020-08
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通讯作者：
Wei Jiang;Haodan Yang;Kefu Yu;Yinxian Song;Jian-xin Zhao;Yue‐xing Feng;T. Han;Xingyuan Wu;Zhiming Ning;Shendong Xu;Yinghui Wang
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作者：
Wei Jiang;Haodan Yang;Kefu Yu;Yinxian Song;Jian-xin Zhao;Yue‐xing Feng;T. Han;Xingyuan Wu;Zhiming Ning;Shendong Xu;Yinghui Wang
过量的人为磷（P）提供给海洋系统，这可能会危及生态系统的结构和功能，改变了磷平衡，其流量翻了两番。然而，由于磷源的多样性，人类活动的不可预测性和可变性，以及缺乏长期记录，仍然不确定过量磷的影响在水生生态系统中持续多久，以及它是否刺激总初级生产力。本研究利用中国南海西沙群岛一个环礁珊瑚骨骼中的地球化学代用指标，重建表层海水中磷的历史分布模式。除了有明确记载的一段短时期的鸟粪开采外，该环礁在很长一段时间内保持着自然状态。对1851年以来的珊瑚骨骼的分析清楚地表明，20世纪60年代表层海水中的P浓度异常增加。我们推断，当时的鸟粪提取导致海水P浓度的长期平衡突然增加。磷的加入似乎在磷矿开采停止后至少持续了30年，磷的衰变期比其他元素的衰变期长。珊瑚P/Ca和δ 13 C的相似时间趋势表明，海洋初级生产力的提高与P的增加有关。短期内的大量输入，以及P的长期持续影响，可以作为营养盐污染的珊瑚礁的自然生态模拟。
Excess anthropogenic phosphorus (P) supplied to marine systems, which may subsequently jeopardize ecosystem structure and function, has altered the P balance and quadrupled its flow. However, due to the diversity of P sources, the unpredictability and variability of human activities, and the absence of long‐term records, it remains uncertain how long the effects of excess P persist in aquatic ecosystems, and whether it stimulates gross primary productivity. In this study, we utilized geochemical proxies in coral skeletons from an atoll in the Xisha Islands of the South China Sea to reconstruct historical patterns of P in surface seawater. This atoll has remained in a natural state for an extended period of time, except for a short period of unambiguously documented guano extraction. Analyses of coral skeletons dating back to 1851 CE distinctly show that the P concentration in surface seawater increased abnormally in the 1960s. We deduced that guano extraction at that time led to an abrupt increase in the long‐term equilibrium of seawater P concentration. Subsequent P addition appeared to have continued for at least ~30 years after phosphorite exploitation ceased, and P showed a decay period that was longer than that of other elements. Similar temporal trends of coral P/Ca and δ13C indicated that elevated marine primary productivity was associated with increased P. Large inputs within a short period, as well as the continued influence of P over the long term, can serve as a natural ecological analog for coral reefs subject to nutrient contamination.