State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
Environ Pollut. 2022 Aug 1;306:119350. doi: 10.1016/j.envpol.2022.119350. Epub 2022 Apr 28.
Lake eutrophication remains a serious environmental problem of global significance, and phosphorus (P) plays a key role in lake eutrophication. Internal P loading, as a result of P release from sediments, is gathering more and more recognition as an important source governing the P availability in these ecosystems. Anoxic condition can promote the release of P associated with Fe oxides, which has already been a consensus. However, it is still unknown whether the anoxic conditions induced by eutrophication act to intensify or weaken the regeneration of organic P (P) in sediments. We selected the Hongfeng Reservoir, a typical sub-deep lake, to study the regeneration behaviours of C and P in the sediments buried before and after eutrophication. The results showed that P did not significantly increase with the rapid increase in organic C (C) since eutrophication occurred. Furthermore, the organic C/P ratio was much higher in sediments buried after eutrophication than in those buried before, which indicated that P regeneration had been significantly enhanced since eutrophication occurred. Based on C/P ratios, our estimation suggested that the P regeneration and P release from sediment to water approximately enhanced 45.2% ± 8.7% and 34.5% ± 9.8%, respectively. Elevated primary productivity (algae) and the corresponding hypoxic/anoxic condition, both caused by eutrophication, promoted P biogeochemical cycle in the sub-deep reservoir. This study further verifies the significant contribution of regenerated P to the internal P load, and highlights the importance of controlling P release from sediments in order to restore clear water ecosystems in sub-deep lakes or reservoirs.
湖泊富营养化仍然是一个具有全球意义的严重环境问题，而磷 (P) 在湖泊富营养化中起着关键作用。内部磷负荷是由于沉积物中磷的释放而产生的，它作为控制这些生态系统中磷可利用性的重要来源，正受到越来越多的关注。缺氧条件可以促进与铁氧化物结合的磷的释放，这已经是一个共识。然而，目前仍不清楚富营养化引起的缺氧条件是会加剧还是削弱沉积物中有机磷 (P) 的再生。我们选择了一个典型的亚深型湖泊——红枫水库，来研究富营养化前后沉积物中碳和磷的再生行为。结果表明，自从富营养化发生以来，磷并没有随着有机碳 (C) 的快速增加而显著增加。此外，富营养化后埋藏的沉积物中的有机碳/磷比远高于富营养化前埋藏的沉积物，这表明自富营养化发生以来，磷的再生已经显著增强。根据 C/P 比值，我们的估计表明，磷的再生和磷从沉积物向水体的释放分别增强了约 45.2%±8.7%和 34.5%±9.8%。富营养化引起的初级生产力（藻类）的升高和相应的缺氧/厌氧条件促进了亚深型水库中磷的生物地球化学循环。本研究进一步证实了再生磷对内部磷负荷的重要贡献，并强调了控制沉积物中磷释放对于恢复亚深湖泊或水库清水生态系统的重要性。
