中国浅海贝藻养殖对海洋碳循环的贡献

中国是浅海贝藻养殖的第一大国，年产量超过1 000万t。根据贝藻养殖产量、贝藻体内碳元素的含量及其贝类能量收支，推算出2002年中国海水养殖的贝类和藻类使浅海生态系统的碳可达300多万t，并通过收获从海中移出至少120万t的碳。该结果不仅为探讨全球“遗漏的碳汇”问题提供了一个新的线索，同时也证明了浅海的贝类和藻类养殖活动直接或间接地使用了大量的海洋碳，提高了浅海生态系统吸收大气CO2的能力。另外,贝藻的养殖活动与浅海生态系统的碳循环之间关系复杂，相互作用明显，因此，它的生物地球化学过程是一个值得深入研究的科学问题。

THE CONTRIBUTION OF SHELLFISH AND SEAWEED MARICULTURE IN CHINA TO THE CARBON CYCLE OF COASTAL ECOSYSTEM

China is the largest mariculture country of shellfish and seaweed in the world. The total annual yields of these in 2002 are more than 10 million tons. Among of which, the yields of seaweed and shellfish are 1.3 and 9.7 million tons, respectively. Seaweeds can transform dissolved inorganic carbon into organic carbon by photosynthesis; filtering shellfish can clear out particle organic carbon by feeding activity and through the process of calcification a lot of carbon can be imbedded into the shells at the form of CaCO3. Especially, a mass of carbons can be removed out of ocean through harvest, which must have great influence on the carbon cycle of coastal ecosystem. Through the activity of shellfish and seaweed mariculture, there were more than 3 million tons carbon being utilized and about 1.2 million tons carbon being taken away from the shallow sea by harvesting, which is calcultated basing on the data of annual production, the C content of both shellfish and seaweed and the energy budget of shellfish. Most important was that there were about 670000 tons carbon were fixed by shells and became the long term carbon sink. The result not only discusses a new clue for probing into the question of “missing sink” in the global carbon cycle, but also testifies that the aquaculture of shellfish and seaweed in the coastal ocean can utilize a great deal of oceanic carbon directly or indirectly and improve the capacity of shallow sea absorbing atmospheric CO2. In addition, the relationship between the aquaculture and the carbon cycle of the coastal ecosystem is very complicated and its interaction is evident, consequently, its biogeochemical process should be paid great attention for further and deeply study as a science problem.