乐清湾、三门湾主要滤食性养殖贝类碳收支的研究

Study on carbon budget of main bivalves in Yueqing Bay and Sanmeng Bay

利用自然海水流水培育方法,对乐清湾、三门湾主要滤食性养殖贝类—太平洋牡蛎(Crassostrea gigas)、僧帽牡蛎(Ostrea cucullata)、泥蚶(Tegillarca granosa)、缢蛏(Sinonovacula constricta)的摄食生理参数进行了测定,根据能量平衡原理估算这些贝类的碳收支情况。结果表明:贝类通过滤食颗粒有机物摄取有机碳源后,一部分通过粪便直接排出体外,部分通过贝类自身的呼吸作用被消耗掉,极少部分碳通过排泄代谢排出体外,结余部分的碳即生长碳作为贝类自身的生长或性腺发育的生长碳而成为贝类的身体组成成分。春季太平洋牡蛎、僧帽牡蛎、泥蚶、缢蛏的净生长率分别为53.95%、65.78%、55.13%、28.12%,其生态效率分别为16.33%、22.10%、6.09%、6.81%。根据测算,2002年春季,乐清湾和三门湾养殖贝类每日从海水中摄取POC分别达到44.43 t和76.88 t之多,消耗海水中的氧气达到了50.68 t和96.93 t,排氨氮达4.35 t和7.97 t,两湾养殖贝类每天排出的粪便物干重更是达到370 t和580 t以上。

The feeding physiological parameters of main cultured bivalves Crassostrea gigas, Ostrea cucullata, Tegillarca granosa and Sinonovacula constricta were measured in Yueqing bay and Sanmeng bay by means of flowing natural sea water. The carbon budgets of four main bivalves were estimated according to energy balance principle. The result indicated that bivalves obtain carbon source by filtering organic grain, and then some parts were directly discharged as dejection, some parts were consumed by breathing, and a little was discharged by excretion, the remaining carbon namely the growth carbon which becomes the organism composition of the bivalves for its growth and development. In spring, the net growth rate of C. gigas, O. cucullata, T. granosa and S. constricta was 53.95% ,65.78% ,55.13% ,28.12%, and the ecological efficiency was 16.33%, 22.10%, 6.09%, 6.81% respectively. The assessment indicated that in spring of 2002, cultured bivalves in Yueqing Bay and Sanmen Bay taked POC from sea water reached as much as 44.43 t and 76.88 t per day; and consumed oxygen in sea water reached which 50.68 t and 96.93 t; excrete ammonia and nitrogen reached 4.35 t and 7.97 t. Dry weights of discharged dejection of the cultured bivalves in these two bays were even more than 370 t and 580 t.