北极楚科奇海对太平洋入流水溶解态硅的改造作用

The biological carbon pump in the polar ocean is largely regulated by the diatoms and other siliceous organisms. Large uncertainty still remains in the predictions of the marine carbon sink capacity of the Arctic Ocean under rapid climate change, with one of the constrains lies in the inadequate understanding of biological pump dominated by the silicon and other nutrient elements. Dissolved silica derived from the Pacific inflow is the most important source of silicon supporting the growth of diatoms in the Arctic Ocean, and one of the controlling factors of the biological pump in this realm. Previous studies have demonstrated obvious modification of dissolved silica by the biological process (such as biological assimilation and removal) occurred in the shelf during its northward transportation to the Arctic basin. However, there is still a lack of quantitative understanding of these processes. In this project, silicon isotopes will be measured for the dissolved and particulate samples collected from the Chuckchi Sea, together with the nutrient concentration and hydrological parameters, we aim to investigate the modification of Pacific-origin dissolved silica in terms of flux and silicon isotopic composition on the Chuckchi Sea shelf, estimate the consumption and regeneration ratio of dissolved silica in the water column, and explore the potential impact of phytoplankton diatoms and ice diatoms on the siliceous biological pump in the polar oceans. The results obtained in this project will provide improved understanding of nutrient cycling and other biogeochemical processes for better evaluating the response and feedback of Arctic Ocean biological pump and carbon cycle to climate and environmental changes.

极地海域的生物碳泵很大程度受控于硅藻等硅质生物泵。快速气候变化下北冰洋海洋碳汇能力的预测仍有很大的不确定性，其中一个制约因素是对硅等营养盐控制的生物泵过程理解不足。太平洋入流水携带的溶解态硅是支撑北冰洋硅藻生长的最主要硅来源，也是调控北冰洋生物泵过程的主控因子之一。已有结果表明，在硅向北冰洋海盆传输过程中，陆架生物过程对溶解态硅存在显著的利用和迁出等改造过程，但目前仍缺乏定量化的研究。本项目拟选取楚科奇海为研究区域，以硅同位素为主要技术手段，结合营养盐浓度、水文参数等，认识楚科奇海陆架上的生物地球化学过程对太平洋入流水溶解态硅通量和同位素组成的改造，估算陆架水体中硅的消耗、再生比例，探讨浮游硅藻和海冰硅藻对极地海域硅质生物泵的影响。本项目所得成果将深化对极地海域营养盐循环等生物地球化学过程的认识，有助于更好地预测北冰洋生物泵和碳循环对气候变化的响应和反馈。

极地海域的生物碳泵很大程度受控于硅藻等硅质生物泵。快速气候变化下北冰洋海洋碳汇能力的预测仍有很大的不确定性，其中一个制约因素是对硅等营养盐控制的生物泵过程理解不足。太平洋入流水携带的溶解态硅是支撑北冰洋硅藻生长的最主要硅来源，也是调控北冰洋生物泵过程的主控因子之一。已有结果表明，在硅向北冰洋海盆传输过程中，陆架生物过程对溶解态硅存在显著的利用和迁出等改造过程，但目前仍缺乏定量化的研究。本项目选取楚科奇海为研究区域，以硅同位素为主要技术手段，结合营养盐浓度、水文参数等，认识楚科奇海陆架上的生物地球化学过程对太平洋入流水溶解态硅通量和同位素组成的改造，估算陆架水体中硅的消耗、再生比例，探讨浮游硅藻和海冰硅藻对极地海域硅质生物泵的影响。本项目所得成果将深化对极地海域营养盐循环等生物地球化学过程的认识，有助于更好地预测北冰洋生物泵和碳循环对气候变化的响应和反馈。共发表论文3篇，其中SCI论文2篇，EI论文1篇；培养研究生1名；参加学术会议2次；出国访学1次。