桑沟湾贝类养殖区沉积碳库年汇入速率的高分辨率记录及其对人类养殖活动的响应

High-resolution records of the rate of carbon accumulation in the shellfish aquaculture area in Sanggou Bay and its response to human aquaculture activities

中文关键词: 沉积碳库  汇入速率  海水养殖  桑沟湾

英文关键词: Sedimentary carbon pool  Accumulation rate  Marine aquaculture  Sanggou Bay

中文摘要:

      本研究对2014年取自桑沟湾贝类养殖区的柱状沉积物进行分析，测定每层沉积物中总碳(TC)、总有机碳(TOC)和总氮(TN)的质量分数，并计算总无机碳(TIC)、海源性有机碳(Cm)和贝壳无机碳(Shell-IC)的质量分数以及各组分碳在总碳中的贡献率，同时对其年汇入速率(BF)进行估算。结合210Pb测年法，研究近80年沉积碳库各种碳的年汇入速率的高分辨率记录，发现其中TC、TIC、TOC、Cm和Shell-IC的平均含量分别为1.09%、0.75%、0.34%、0.15%和0.06%。研究还发现，TIC是TC的主要形式，在1960—2010年的贡献率保持在60%以上。Cm的质量分数在2010年前无较大幅度的波动，但在2010年后显著增加，使得Cm/TC及TOC/TC也显著提升。Shell-IC在养殖活动开始后至2000年一直处于较低水平。各组分碳的年汇入速率在1960—2000年间随海水养殖活动呈现相应的变化，之后由于养殖规模和格局的调整，BFCm、BFTOC和BFTC显著升高，BFTIC降低，BFShell-IC先升高后降低。桑沟湾的海水养殖活动影响着贝类养殖区沉积碳库的组成和年汇入速率，碳库各组分的变动也体现出与之相应的变化。本研究详细描述了人类海水养殖活动在开始后的50年里对沉积碳库年汇入速率的影响特征，也为今后陆架海区水产养殖活动的合理规划提供参考。

英文摘要:

      In this study, columnar sediments taken from the shellfish aquaculture area of Sanggou Bay in 2014 were analyzed to determine the mass fraction of total carbon (TC), total organic carbon (TOC), and total nitrogen (TN) in each layer of sediments, and to calculate the mass fraction of total inorganic carbon (TIC), marine organic carbon (Cm), shell inorganic carbon (Shell-IC), and their contribution ratios to TC. The accumulation rate (or burial flux, BF) of each component was estimated. High-resolution records of various carbon accumulation rates in sedimentary carbon pools in the last 80 years were obtained using the 210Pb dating method. The average contents of TC, TIC, TOC, Cm, and Shell-IC were 1.09%, 0.75%, 0.34%, 0.15%, and 0.06%, respectively. Results showed that TIC was the main form of TC, with a contribution ratio greater than 60% between 1960 and 2010. The mass fraction of Cm did not fluctuate significantly before 2010, but increased significantly after 2010, significantly increasing Cm/TC and TOC/TC. Shell-IC remained at a low level from the start of aquaculture activities until 2000. The carbon accumulation rate of each component responded to human marine aquaculture activities from 1960 to 2000. Due to the modification of aquaculture scale and pattern after 2000, BFCm, BFTOC, and BFTC increased significantly, BFTIC decreased, and BFshell-IC first increased and then decreased. Marine aquaculture activities in Sanggou Bay influenced the composition and accumulation rate of the carbon pool in the shellfish aquaculture area, and the carbon components responded to changes in aquaculture activities. The research results describe the effects of human aquaculture activities on the accumulation rate of sedimentary carbon pools in detail over 50 years after the start of aquaculture activities. This study also provides a reference for rational planning of aquaculture activities in continental shelf areas in the future.