贝藻类养殖碳汇核算与综合温室潜力评估研究进展

Progress in carbon sequestration estimation and comprehensive warming potential assessment in marine aquaculture of shellfish and seaweed

海水养殖可能是实现我国碳中和目标的有效途径之一。贝、藻类养殖是海水养殖的主要组成部分,可以通过碳移除(从海水中收获)、碳固定(形成贝壳)等方式成为有效的碳汇。因此,中国作为海水养殖大国,具有较大的碳汇潜力。然而,目前关于贝、藻类养殖过程中碳汇的计算、评估、监测等还没有统一的标准,对于其碳汇边界的定义(如储藏年限、周转周期等)也不清晰。本文阐述了典型贝、藻类养殖碳汇的潜力,认为碳汇的计算不仅仅要考虑储存碳,还要考虑养殖过程中由于呼吸等过程排放的碳;提出了贝、藻类养殖碳汇测算过程中存在的问题,认为目前常用的称重法等无法准确反应养殖系统的碳汇潜力;建议在未来养殖碳汇测算中首先明确碳汇边界问题(如使用长、短周期碳汇的概念)。最后,本文讨论了贝、藻类养殖生态系统综合温室效应评估的必要性,建议在碳汇核算过程中同时考虑非二氧化碳温室气体(如甲烷、氧化亚氮)的作用。

Marine aquaculture may be one of the effective ways to achieve the goal of carbon neutrality in China.The shellfish and seaweed aquaculture is an important part of the marine aquaculture by sequestrating carbon from the seawater(harvest)and sealing it into the sediments in the form of shells,and thus making an effective carbon sink in marine aquaculture.As an important aquaculture country,China has a great potential of carbon sequestration in future.However,there is not a official protocol in the calculation,evaluation,and monitoring of carbon sink in the field of shellfish and seaweed aquaculture at present.Also,it is not clear on the definition of the boundary of carbon sink,such as storage life and turnover year.This study presents the potential of carbon sequestration and suggests combing the fixing carbon and releasing carbon via respiration when calculating the carbon potential during mariculture.We raise the issues of carbon sink calculation and point out that the weighting method is not enough to reflect the reality of carbon sink potential.We suggest that figuring out the boundary of carbon sink(e.g.,by using the definition of long/short carbon period)should be the first step to constrain the carbon sink potential of mariculture.Finally,we discuss the necessity in the evaluation of the warming potential in shellfish and seaweed aquaculture and propose taking considerations of the role of non-carbon dioxide greenhouse gases in the carbon sink calculation.