内陆渔业生态系统的碳循环特征及碳汇机制

渔业是水体生态系统中惟一可控的有效增汇产业, 碳汇渔业是水体生态系统中惟一的“碳汇产业”。为了更好地把握内陆渔业生态系统碳循环及碳汇机制的特征, 目前的重点研究应包括内陆渔业水域生态环境(包括自然水域和池塘)中碳循环的规律, 碳赋存形态的归转, 各类水产品生物对碳汇的贡献途径和份额以及相应的计量体系和评价模型等; 同时, 希望合理地估算及测定内陆渔业水体、水–气界面间CO2通量, 把握内陆渔业水域生态系统碳源/碳汇的动态, 进而构建内陆渔业水域生态系统的环境碳/生物碳/碳通量时空变化的信息库。

Characteristics of carbon cycles and mechanism of carbon sink in inland fishery ecosystem

Inland fishery carbon sink (IFCS)refers to the process and mechanism in which fishery organisms absorb and sequestrate CO2 sequestrate CO2 in the water and remove it from the water, and consequently, inland carbon sink fishery (ICSF) will be any fishery activity that effectively promotes a relative increase of IFCS. Phytoplankton fixes CO2 through photosynthesis and converts it into organic carbon. Quite much of it is taken up by major freshwater herbivorous and filter-feeding fish and mussels, and accordingly, carbon can be cascaded through aquatic food webs and removed by capture fisheries and aquaculture. Therefore, ICSF can not only provide large quantities of nutritious food, but also play a critical role in carbon sequestration and removal. Carbon in freshwater ecosystems can be made up of different chemical components, like particulate organic and inorganic carbon, dissolved inorganic and organic carbon, which are convertible with high dynamics. It is noteworthy that unsustainable fishing related activities will jeopardize the potential capacities and even ecosystem services of IFCS. Therefore, the importance of IFCS and ICSF must be highlighted. A more recent study suggested that aquaculture ponds (110 830 km2) sequester an estimated 16.6 million tonnes/year of carbon globally, and the most carbon sequestration occurs in Asia and particularly in China (94% and 55.9% of global aquaculture pond area, respectively). Fishery will be the only controllable industry that is possible to effectively increase the carbon sink capacity in aquatic ecosystem, and the carbon sink fishery will be the only carbon sink industry in aquatic ecosystem. To better understand the mechanism of carbon sink/source, the current focus of study should be on the natural laws of carbon cycles in inland fishery ecosystem (including natural waters and ponds), form conversion between different chemical components, the carbon footprint for each of the different inland fisheries and aquaculture activities, and the corresponding assessment methods and models. At the same time, attention should also be paid to calculating realistic estimates of CO2 fluxes in inland fishery waters and at the water-atmosphere interface, understanding the dynamics of carbon sink/source, and establishment of the information platform for environmental carbon/biological carbon/carbon fluxes of ICSF.