【作者】 张学雷；

【导师】 张志南； 朱明远；

【作者基本信息】 中国海洋大学 ， 环境科学， 2003， 博士

【摘要】 本文通过历史资料收集、现场调查、定点连续观测、现场模拟实验等综合性方法研究了滤食性海水贝类养殖对桑沟湾生态环境的影响以及饵料、温度等环境条件对栉孔扇贝的摄食和代谢行为的影响，在此基础上构建了栉孔扇贝生长动力学模型和桑沟湾贝类混养生态模型，研究了桑沟湾的贝类养殖容量。结果如下： 大规模集约式贝类养殖对海洋生态系统产生了明显的影响。长期(十年际)影响包括贝类养殖区的无机氮营养盐含量增加、初级生产力降低、网采浮游动植物密度下降、海水透明度提高等；通过海流、溶解氧、叶绿素荧光、浊度、水温、盐度、pH等多参数的定点连续10d的同步观测表明，贝类养殖在短期(日、小时际)内对其所处环境的影响包括养殖设施对潮流流速的削减、悬吊养殖贝类的摄食对潮流引起的浮游植物生物量波动的平抑等。 对桑沟湾沉积物和上覆水的模拟现场培养、测定结果表明：与其他近岸浅海环境相比，在贝类养殖影响下的桑沟湾沉积物耗氧率处于中等偏上水平，而沉积物—海水界面营养盐通量则处于中等偏下水平。由此估算，桑沟湾底层对贝类生物沉积下来的有机C的埋置效率为仅40％(5月)和3％(8月)，而底层矿化的POC占水层初级生产力的102％(5月)和67％(8月)；底层营养盐通量对水层初级生产所需无机N的贡献为14％、对无机P有负的贡献(表现为净吸收)。桑沟湾沉积物—水界面铵氮和溶解氧通量均与沉积物表层的C、N含量正相关，活性磷酸盐通量则与沉积物耗氧速率和上覆水的磷酸盐浓度相关。 对贝类生态生理学的研究表明：栉孔扇贝主要通过改变滤清率维持其摄食速率，滤清率同时受饵料体积浓度和叶绿素a含量调节但以饵料体积浓度调节为主，这种调节呈单峰曲线变化，当饵料接近在自然海水中的条件时滤清率即达到最高;通过对饵料的过滤处理、形成假粪和进食前处理等机制，扇贝可同时选择性地摄食海水中的颗粒有机物和浮游植物性饵料，这两种选择性相互影响但以对颗粒有机物的选择性为主:扇贝对摄入消化道内的饵料的吸收率受进食饵料有机质含量的正调控而与季节变化无显著相关性;扇贝代谢中的O:N比在饥饿时最低，随摄食速率增加而提高;体重和适宜的温度对扇贝的摄食和呼吸代谢均有促进作用。 依据上述摄食生理实验和其他相关研究结果、按照能量收支概念建立的栉孔扇贝个体生长动力学模型，涵盖了对不同饵料和温度条件下扇贝的摄食和代谢等生理活动、尤其是对活的浮游植物、碎屑性有机物和颗粒无机物的选择性摄食与处理的动态模拟。生长模型的计算结果与桑沟湾养殖栉孔扇贝自苗期到收获过程生长的现场测定数据相符，同时也预测了不同养殖方式下和不同养殖区的扇贝生长的差异，表明该模型可以用于养殖容量研究。 在上述栉孔扇贝生长模型和他人发表的牡砺生长模型的基础上，本文建立了贝藻混养亏维生态模型，并应用于桑沟湾栉孔扇贝、太平洋牡砺和海带混养生态系统的模拟。该模型通过模拟不同播苗密度和收获方式下的产量，以及不同混养方式对海洋生态系统的影响来确定养殖容量。利用该模型的研究结果表明:当养殖密度分别增加到目前桑沟湾扇贝和牡蜗放苗量的2倍和巧倍时总产量最高(达到养殖容量)，但同时单位面积产量和产量/播苗比均会降低，因此生产效率是下降的;扇贝放苗量增加到目前的15倍，牡砺增加到30倍时会导致养殖生产崩溃，同时生态系统也发生改变(桑沟湾由向其外海一黄海一输出初级生产产品变为需要黄海向其输入初级生产产品)。这些结果表明该模型可以迅速模拟养殖生物量和生态系统的变化，是多元海水养殖生产管理的有益工具。更多还原

【Abstract】 The impacts of marine filter-feeding mollusks’ farming on the environment, and environmental conditions (food and temperature)’ regulation on feeding behavior of the Zhikong scallop Chlamys farreri is studied in Sanggou Bay, China, through historical data, field survey, mooring continuous monitoring and in situ experiments. Then, a responsive growth model is established for the Zhikong scallop and an ecosystem model is built for assessment of the carrying capacity of the polyculture in Sanggou Bay. The main results are summarized as follows:Large-scale intensive culture of bivalves poses significant impacts on the marine ecosystems. The long-term (decadal) impacts include enrich of inorganic nitrogen in the water column, decrease of primary productivity and net-plankton density and increase of seawater transparency. Accordingly, short-term (inter- daily or hourly) changes, as revealed by simultaneous applied current, dissolved oxygen, chlorophyll florescence, turbidity, temperature, salinity and pH sensors for continuous monitoring up to 10 days, include reduction of current speeds by the culture installations, control of phytoplankton biomass over tidal variation by feeding of the suspension-cultured bivalves.Measurements with remote incubation of intact cores of sediment with overlying water from Sanggou Bay, indicate that sediment-water nutrients (ammonium and phosphate) fluxes and their contribution to the primary production in the water column in the bay under shellfish culture impacts, are relatively low compared with other shallow coastal waters, whilst the sediment oxygen demand rates are at middle-high levels. The sediment respiration in Sanggou Bay is estimated to represent mineralization of 102% (May) to 67% (August) of the primary production in the water column, and only 40% (May) to 3% (August) of the pariculate organic carbon that is imported to the sediment via bivalve biodeposit is buried in the sediment. The sediment nitrogen release contributes to 14% requirement of inorganic N for the primary production in the water column whereas net absorption of phosphate makes a negative contribution. Both sediment-water N fluxes and sediment oxygen demand(SOC), however, arepositively related with the organic carbon and nitrogen contents in the surface sediment while P flux is related to SOC and phosphate level in the overlying water.Results from the ecophysiological experiments with Zhikong scallops indicate: i) That scallops rely mainly on regulation of clearance rates to maintain their maximal food intake, and clearance rates are regulated to particle volume (more important) and chlorophyll a content of the seston, with an unimodal effect resulting in maximal clearance rate at food conditions in the natural seawater range, ii) That scallops selective feed on organics (more important) and phytoplankton through retention on the gill, psuedofaeces production and post-ingestion processing of the food, iii) That net absorption efficiency is positively related with organic content of the ingested food, iv) That the 0:N molar ratio is lowest when the scallop is starved and the ratio increases as feeding inceases. And v) that body weight and amenable temperature have positive effects on scallop feeding and respiration rates.Hereafter, a dynamic growth model, based on the concept of net energy balance, is configured for the Zhikong scallop individuals, using functions generated from the above experimental data and relavant published data. The model covers dynamic simulation of rapid and sensitive adjustments in feeding and metabolism as observed in response to the highly changeable food and temperature conditions. Notable novel elements include resolving significant adjustments in the relative processing of living chlorophyll-rich phytoplankton organics, non-phytoplankton organics and the remaining inorganic matter during both differential retention on the gill and selective pre-ingestive rejection within pseudofaeces. The model is validated with measurements of growth data of the cultured sc更多还原