贝藻混养系统中贝类食物来源的定量分析

IOCAS-IR > 海洋环流与波动重点实验室

	贝藻混养系统中贝类食物来源的定量分析
其他题名	Evaluation of food sources of bivalve in seaweed and filter-feeding bivalve polyculture ecosystem
	许强
学位类型	博士
	2007-06-06
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	食物来源滤食性贝类大型藻类稳定同位素比值法脂肪酸标志法
摘要	应用稳定碳、氮同位素比值法和脂肪酸标志分析法，较为系统地研究了贝藻混养系统中滤食性贝类的食物来源，评估了大型藻类对混养系统及滤食性贝类的物质贡献。主要研究结果如下： 1.综述了典型生态系统中大型藻类和滤食性贝类各自的生态学地位和作用，大型藻类与滤食性贝类不仅在水体营养盐方面存在互利关系，二者在物质循环与收支方面同样具有耦合性，大型藻类提供的颗粒态有机质可以为滤食性贝类提供饵料来源。 2.总结了稳定同位素比值法和脂肪酸标志法在海洋生态系统食物来源及食物网分析中的应用，并建立了两种方法的具体操作规程。 3.分析了栉孔扇贝Chlamys farreri和海带Laminaria japonica混养系统中海带碎屑形成及释放不同阶段的生态学特征，评估了碎屑对扇贝的饵料贡献。海带在6周内释放了自身约27％的碳；碎屑形成及释放过程中C:N比值显著下降，同时伴随着旺盛的细菌降解，碎屑中也发现有大量硅藻类和原生动物存在。稳定同位素分析证实海带碎屑是混养期间扇贝的主要食物来源。 4.查明了春季胶州湾潮间带自然分布的长牡蛎Crassostrea gigas、紫贻贝Mytilus galloprovincialis和湾内浅海筏式养殖栉孔扇贝的可能食物来源。湾内栉孔扇贝饵料组成中浮游硅藻类为最主要部分，同时混杂有陆源有机质和细菌类物质；潮间带自然生长的牡蛎和贻贝饵料组成中，浮游植物占86.2-89.0％，种类组成中除硅藻外还包括一定比例的金藻和甲藻类；潮间带繁盛的孔石莼Ulva pertusa藻床为两种贝类提供了8.7-11.0％的补充食物来源。 5.揭示了桑沟湾贝藻混养海区春、夏季栉孔扇贝饵料来源组成情况及其季节变化，评估了海带养殖区碎屑碳量季节变化及海带来源碳对扇贝组织碳的贡献。结果表明，湾内贝藻混养区碎屑碳量为75.52-265.19 μg l-1，其在水体总颗粒态有机碳中的比例为25.6-73.8％。海带来源碎屑碳对栉孔扇贝组织碳的贡献比例为14.1-42.8％，且与水体碎屑碳比例的季节变化存在极显著相关性(F=0.992, P=0.004)。5月份湾外海带养殖区水体碎屑碳量为110.12-144.71 μg l-1，显著高于湾内无海带区（75.52 μg l-1），湾外养殖的扇贝组织中海带来源碳比例为22.0-24.1％，显著高于湾内单养区扇贝（9.6％）。估算结果表明，桑沟湾每年收获的6967吨（总湿重）栉孔扇贝中，海带提供了约57.1吨碳，换算为海带干物质为219.6吨。脂肪酸标志分析结果表明，2月份至8月份硅藻类在扇贝饵料组成中比例逐渐下降，而细菌类比例逐渐升高。整个采样期间，EPA/DHA比例较低，说明扇贝饵料组成中可能包括高DHA含量的组分。
其他摘要	Food sources of filter-feeding bivalve in seaweed and filter-feeding bivalve polyculture ecosystem were determined and quantified using stable carbon and nitrogen isotopes and lipid biomarkers. The contribution of seaweed organic materials to bivalves was also evaluated. Results were listed as follows: 1.The ecological functions of seaweed and filter-feeding bivalve and their couple in seaweed-based ecosystems were reviewed. Seaweed has a firm top-down control on the nutrient level of the water; meanwhile, the majority of its primary production is released as particulate and dissolved organic materials, which can supply important food sources to filter feeding bivalves. 2.The application of stable isotope ratios and lipid biomarker in marine food web analysis was reviewed. Detailed analyzing procedures of two methods were established. 3.The detritus release process of kelp Laminaria japonica and its trophic importance to co-cultured scallop Chlamys farreri were examined for duration of 6 weeks in a laboratory polyculture system using fatty acid biomarkers and stable isotope analysis. There was a loss of 27% of wet tissue weight in the fresh kelp after the 6 week experiment. The C:N ratio of decomposing kelp blade and detritus were significantly lower than fresh tissue. Lipid biomarkers indicated that, bacteria were mostly responsible for the biodegradation of kelp tissue. Diatom and protozoan/flagellate were also found in kelp detritus. The stable isotopic results suggested that kelp detritus is trophically important to suspension feeding bivalves in the laboratory polyculture system. 4.Food sources of intertidal oyster Crassostrea gigas, mussel Mytilus galloprovincialis and subtidal cultured scallop C. farreri in Jiaozhou Bay, (Qingdao, China) were determined by fatty acid and stable isotope analysis. Cultured scallop feeds mainly on diatoms together with some amount of bacteria and terrestrial materials. Flagellates are part of intertidal bivalves’ planktonic food source besides diatoms, and Ulva pertusa (Chlorophyta) seaweed bed also supplied important food sources to intertidal bivalves. Stable isotope analysis showed that phytoplankton contributed 86.2-89.0% to intertidal bivalves’ carbon budget; macroalga U. pertusa origin source had a contribution of 8.7-11.0%. 5.Food sources of cultured scallop C. farreri were investigated in a seaweed and filter-feeding bivalve polyculture area in Sanggou Bay (Rongcheng, China). The trophic importance of kelp-derived particulate organic materials in the polyculture system was also evaluated. From February to August, detritus carbon in the water ranged from 75.52 to 265.19 μg l-1, which occupied 25.6% to 73.8% of total particulate organic carbon (POC). Both of the carbon amount and proportion changed along with the growth and harvest process of the kelp. Cultured scallop obtained 14.1% to 42.8% of its tissue carbon from kelp detritus, and the percentage varied seasonally with the detritus carbon proportion in the water, and a close correlation was found between them (F=0.992, P=0.004). In May, the detritus amount in the kelp cultivation area outside of the bay was significantly higher than the bivalve cultivation area in the bay, and scallops cultured in these two sites also had different proportions of detritus diet. Evaluating result showed that, of all the 6967 tons (wet weight) of scallop production each year, kelp contributed about 57.1 tons of carbon (219.6 tons in dry mass) as a whole. Lipid biomarkers indicated that, the percent of diatom declined in scallop’s food composition, whereas that of bacteria increased from February to August. Scallops cultured in Sanggou Bay showed a higher EPA/DHA ratio than Jiaozhou Bay, suggesting that there were much more food source rich in DHA in Sanggou Bay.
页数	97
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/301
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	许强. 贝藻混养系统中贝类食物来源的定量分析[D]. 海洋研究所. 中国科学院海洋研究所,2007.

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