The historical dependency of organic carbon burial efficiency
The historical dependency of organic carbon burial efficiency
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DOI：
10.1002/lno.10512
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发表时间：
2017-07
影响因子：
4.5
通讯作者：
Alan D. Radbourne;D. Ryves;N. Anderson;Daniel R. Scott
中科院分区：
文献类型：
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作者：
Alan D. Radbourne;D. Ryves;N. Anderson;Daniel R. Scott
许多研究将湖泊视为有机碳埋藏速率的准静态系统，认为对有机碳埋藏速率的主要控制是沉积物的矿化作用。然而，在经历富营养化或少营养化(即改变营养负荷)或气候强迫的系统中，初级生产力的变化将在较长(10年)和较短(季节性)时间尺度上有所不同，影响有机碳积累和随后的永久埋葬的速度。在这里，我们考虑永久OC埋葬在多大程度上反映了一个深单一湖泊(英国罗斯梅尔)的产量变化，该湖泊已经被养殖富营养化(目前的TP>；200μg L−1)，但最近经历了营养负荷的减少。我们比较了使用沉积物圈闭的有机碳通量的多年动态与根据两个210Pb年代的沉积物岩芯估计的较长期埋藏率。最近的沉积物记录表明，大部分原生有机碳被保存下来(∼，95%的有机碳在深层圈闭中被捕获，86%的净有机碳在当代系统中被捕获)，这与普遍认为这种更不稳定的、以藻类为主的有机碳成分在湖泊沉积物中没有得到很好的保存的假设相反。对近几十年来初级生产力发生了变化的湖泊，提出了一种修正的BE计算方法，该方法减少了现有方法利用过去25-150年平均历史沉积物记录所固有的一些问题。我们建议，将所有生物群中的湖泊视为对最近人类影响和气候变化做出动态反应的生态系统(例如)可以提高区域和全球对湖泊OC埋葬的估计。
Many studies have viewed lakes as quasi‐static systems with regard to the rate of organic carbon (OC) burial, assuming that the dominant control on BE is sediment mineralization. However, in systems undergoing eutrophication or oligotrophication (i.e., altered nutrient loading), or climatic forcing, the changes in primary production will vary on both longer (> 10 yr) and shorter (seasonal) timescales, influencing the rate of OC accumulation and subsequent permanent burial. Here, we consider the extent to which permanent OC burial reflects changing production in a deep monomictic lake (Rostherne Mere, UK) that has been culturally eutrophied (present TP > 200 μg L−1), but has undergone recent reductions in nutrient loading. We compare multi‐year dynamics of OC fluxes using sediment traps to longer‐term burial rates estimated from two 210Pb‐dated sediment cores. The recent sediment record demonstrates that most of the autochthonous OC is preserved (∼95% of OC captured in the deep trap and 86% of the NEP in the contemporary system), contrary to widely held assumptions that this more labile, algal‐dominated OC component is not well preserved in lake sediments. A revised method for calculating BE for lakes which have undergone changes in primary productivity in recent decades is developed, which reduces some of problems inherent in existing approaches using historical sediment records averaged over the last 25–150 yr. We suggest that an appreciation of lakes in all biomes as ecosystems responding dynamically to recent human impact and climate change (for example) can improve up‐scaled regional and global estimates of lake OC burial.