Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China.
Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China; Guangxi Key Laboratory of Marine Environment Change and Disaster in Beibu Gulf, Beibu Gulf University, Qinzhou 535011, China.
Sci Total Environ. 2024 Nov 15;951:175824. doi: 10.1016/j.scitotenv.2024.175824. Epub 2024 Aug 26.
Oyster farming activities play a pivotal role in the biogeochemical cycles of coastal marine ecosystems, particularly in terms of sedimentary carbon cycling. To gain deep insights into the influence of expanding oyster culture on the sedimentary carbon cycle, surface sediments were collected from the Maowei Sea, which is the largest oyster farming bay in south China, based on six filed surveys between July 2010 and December 2022. The sediment samples were analyzed for total organic carbon (TOC), total nitrogen (TN), stable carbon and nitrogen isotopes (δC and δN) to evaluate the inter-annual variations in the source contribution to sedimentary organic matter (SOM). The results revealed that the average contents of sedimentary TOC and TN were 0.67 ± 0.41 % and 0.06 ± 0.03 %, respectively. Fluctuations in the C/N molar ratios ranged from 5.8 to 23.6, with an average of 12.6 ± 2.9, indicating a significant terrestrial input contribution to SOM in the study area. Furthermore, the integration of stable isotope analysis and Bayesian mixing model demonstrated a gradual increase in the mean proportion of shellfish biodeposition to SOM, from 12.0 ± 5.6 % in July 2010 to 21.1 ± 7.3 % in December 2022, consistent with the progressive expansion of oyster aquaculture along this coastal area, thereby emphasizing the substantial influence of oyster farming on SOM composition. With the anticipated expansion of oyster farming scale and production in the future, shellfish biodeposition is expected to assume a more important role in shaping SOM dynamics and sedimentary organic carbon cycling in coastal waters. Overall, this study provided an important perspective for better assessing the impact of expanding mariculture scale on coastal biogeochemical cycles, thereby making valuable contributions to future policy formulation concerning mariculture and ecological conservation.
牡蛎养殖活动在沿海海洋生态系统的生物地球化学循环中起着关键作用，特别是在沉积碳循环方面。为了深入了解牡蛎养殖的扩张对沉积碳循环的影响，根据 2010 年 7 月至 2022 年 12 月期间进行的六次实地调查，从中国南方最大的牡蛎养殖场茅尾海采集了表层沉积物。对沉积物样品进行总有机碳 (TOC)、总氮 (TN)、稳定碳和氮同位素 (δC 和 δN) 的分析，以评估沉积有机碳 (SOM) 中有机质来源的年际变化。结果表明，沉积物 TOC 和 TN 的平均含量分别为 0.67 ± 0.41%和 0.06 ± 0.03%。C/N 摩尔比的波动范围为 5.8 至 23.6，平均值为 12.6 ± 2.9，表明研究区域 SOM 中有显著的陆地输入贡献。此外，稳定同位素分析和贝叶斯混合模型的整合表明，贝类生物沉积对 SOM 的平均比例逐渐增加，从 2010 年 7 月的 12.0 ± 5.6%增加到 2022 年 12 月的 21.1 ± 7.3%，与该沿海地区牡蛎养殖业的逐步扩张一致，从而强调了牡蛎养殖对 SOM 组成的重大影响。随着未来牡蛎养殖规模和产量的预期扩张，贝类生物沉积预计将在塑造沿海水域 SOM 动态和沉积有机碳循环方面发挥更重要的作用。总的来说，这项研究为更好地评估扩大海水养殖规模对沿海生物地球化学循环的影响提供了重要视角，为未来的海水养殖和生态保护政策制定做出了有价值的贡献。
