College of Oceanography, Hohai University, Nanjing 210024, China; Laboratory of Marine Hazards Forecasting, Ministry of Natural Resources, Hohai University, Nanjing, 210024, China.
College of Oceanography, Hohai University, Nanjing 210024, China; Laboratory of Marine Hazards Forecasting, Ministry of Natural Resources, Hohai University, Nanjing, 210024, China.
Water Res. 2022 Jun 1;216:118329. doi: 10.1016/j.watres.2022.118329. Epub 2022 Mar 21.
Huge synthetic chemicals and hydrocarbons have been released to inland waters and oceans, composing anthropogenic dissolved organic carbon (ADOC). They complement a large budget for CO. Burial by inland and coastal marine sediments is crucial to reduce this budget. How ecological regime shifts influence the burial ability of ADOC by inland waters and coastal oceans, and what are the differences between them remain largely unknown. We collected sediment cores from an inland lake (Lake Qianhu) and the largest coastal lagoon (Lagoon Pinqing) in China, and chose 16 polycyclic aromatic hydrocarbons (PAHs) to address these issues. Burial ability of PAHs by sediments decreased by 55.1% - 98.5% in Lagoon Pinqing in the period from 1963 to 2018, and by 91.5% - 99.5% in Lake Qianhu in the period from 1970 to 2018. Burial ability and its decrease rate for most PAHs in Lagoon Pinqing were larger than those in Lake Qianhu in the same period. PAHs with higher hydrophobicity were more ready to be buried by both lake sediments and lagoon sediments. Burial ability of most PAHs in Lagoon Pinqing was negative correlated with total phosphorus concentration. In contrast, burial ability of most PAHs in Lake Qianhu was negative correlated with total nitrogen concentration. Regime shifted from phytoplankton to submerged macrophytes dominance in the year of 1976, and from submerged macrophytes to phytoplankton dominance in the year of 1999 in Lagoon Pinqing, driven by nitrogen. Regime shifted from vascular plants to phytoplankton dominance in Lake Qianhu in the year of 1991, driven by phosphorus. Different aromaticity and sources of organic matter related to regime shifts were responsible for the discrepancy of burial ability for PAHs by sediments of these two waters. Our study suggests that burial ability of ADOC by inland and coastal marine sediments will be reduced if eutrophication results in ecological regime shifts, which may undermine the efforts to mitigate global warming.
大量的合成化学品和碳氢化合物已经被排放到内陆水域和海洋中，构成了人为溶解有机碳（ADOC）。它们补充了大量的 CO。内陆和沿海海洋沉积物的埋藏对于减少这一预算至关重要。生态系统的转变如何影响内陆水域和沿海海洋 ADOC 的埋藏能力，以及它们之间的差异，在很大程度上仍然未知。我们从中国的一个内陆湖泊（钱湖）和最大的沿海泻湖（品清湖）采集了沉积物岩芯，并选择了 16 种多环芳烃（PAHs）来解决这些问题。1963 年至 2018 年期间，品清湖沉积物对 PAHs 的埋藏能力下降了 55.1%至 98.5%，1970 年至 2018 年期间，钱湖沉积物对 PAHs 的埋藏能力下降了 91.5%至 99.5%。在同一时期，品清湖沉积物对大多数 PAHs 的埋藏能力及其下降速率均大于钱湖。疏水性较高的 PAHs 更容易被湖泊沉积物和泻湖沉积物埋藏。品清湖大多数 PAHs 的埋藏能力与总磷浓度呈负相关。相比之下，钱湖大多数 PAHs 的埋藏能力与总氮浓度呈负相关。氮驱动的 1976 年，从浮游植物到沉水植物优势，以及 1999 年从沉水植物到浮游植物优势的生态系统转变，驱动了品清湖的生态系统转变。磷驱动的 1991 年，从维管束植物到浮游植物优势的生态系统转变，驱动了钱湖的生态系统转变。与生态系统转变相关的不同芳香度和有机质来源是造成这两种水体沉积物对 PAHs 埋藏能力差异的原因。我们的研究表明，如果富营养化导致生态系统转变，内陆和沿海海洋沉积物对 ADOC 的埋藏能力将会降低，这可能会破坏缓解全球变暖的努力。
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