德国赫姆霍兹研究中心Zhang Wenyan课题组最新的研究成果显示，密集的海底拖网捕捞减少了陆架海洋沉积物的长期碳储量。2024年10月28日出版的《自然—地球科学》发表了这项成果。
据了解，海底拖网捕捞是对大陆架海底沉积物最广泛的人为物理干扰。虽然人们对拖网捕捞引起的底栖生态变化充分了解，但对其对海洋沉积物中长期有机碳储存的影响仍不确定。
研究团队对一个重度拖网地区（北海地区）的大量沉积物和海底拖网捕鱼的数据集进行组合，以探索它们之间潜在的相互依赖性。研究人员以表层沉积物有机碳泥比与多年平均扫掠面积比作为代表的拖网捕捞强度进行比较，发现了一种模式。当拖网捕捞面积比大于1yr-，有机碳泥比显示了对拖网捕捞的系统响应。
三维物理—生物地球化学模拟结果表明，这种模式被归因于拖网捕捞引起的对泥质和有机碳在运输和再沉积过程中的相关动态。沉积有机碳的增加和减少都可能发生在弱拖网捕捞区，而沉积有机碳的净减少出现在强拖网捕捞区。停止拖网捕捞可以恢复沉积碳储量和底栖生物生物量，但它们的恢复发生在不同的时间尺度上。研究结果强调，需要对密集拖网海域进行管理，以增强大陆架海域的二氧化碳封存能力。
附：英文原文
Title: Long-term carbon storage in shelf sea sediments reduced by intensive bottom trawling
Author: Zhang, Wenyan, Porz, Lucas, Yilmaz, Rmeysa, Wallmann, Klaus, Spiegel, Timo, Neumann, Andreas, Holtappels, Moritz, Kasten, Sabine, Kuhlmann, Jannis, Ziebarth, Nadja, Taylor, Bettina, Ho-Hagemann, Ha Thi Minh, Bockelmann, Frank-Detlef, Daewel, Ute, Bernhardt, Lea, Schrum, Corinna
Issue&Volume: 2024-10-28
Abstract: Bottom trawling represents the most widespread anthropogenic physical disturbance to seafloor sediments on continental shelves. While trawling-induced changes to benthic ecology have been widely recognized, the impacts on long-term organic carbon storage in marine sediments remains uncertain. Here we combined datasets of sediment and bottom trawling for a heavily trawled region, the North Sea, to explore their potential mutual dependency. A pattern emerges when comparing the surface sediment organic carbon-to-mud ratio with the trawling intensity represented by the multi-year averaged swept area ratio. The organic carbon-to-mud ratio exhibits a systematic response to trawling where the swept area ratio is larger than yr-1. Three-dimensional physical–biogeochemical simulation results suggest that the observed pattern is attributed to the correlated dynamics of mud and organic carbon during transport and redeposition in response to trawling. Both gain and loss of sedimentary organic carbon may occur in weakly trawled areas, whereas a net reduction of sedimentary organic carbon is found in intensely trawled grounds. Cessation of trawling allows restoration of sedimentary carbon stock and benthic biomass, but their recovery occurs at different timescales. Our results point out a need for management of intensely trawled grounds to enhance the CO2 sequestration capacity in shelf seas.
DOI: 10.1038/s41561-024-01581-4
Source: https://www.nature.com/articles/s41561-024-01581-4