考洲洋饵料生物水平综合评价

在GIS(Geographical Information System)的支持下,利用等级模型对1999年2月(枯水期)和8月(丰水期)考洲洋饵料生物水平进行了综合的分析和评价。枯水期考洲洋整个水域饵料生物的分布较均匀,其密集分布区位于湾西北部、湾口和吉隆河口附近水域,达4级水平,饵料生物较为丰富。丰水期饵料生物水平的变化幅度较大,其密集分布区位于湾中部和望京洲沿岸水域,达4-5级,饵料生物最为丰富,其次为湾口,达4级水平。两个调查航次相比,丰水期的饵料生物水平高于枯水期。主要优势种的变化具有明显的季节交叉和演替现象,浮游植物和浮游动物的主要优势种在不同季节差异较大,而底栖生物的优势种组成在整个调查期间变化不大。调查期间各饵料生物的多样性指数和均匀度均呈现出较大的变化,其最大变化范围分别为0.01-4.49和0.01-0.96,表明湾内饵料生物受外界环境条件影响较大,生物群落组成结构和生物多样性水平不太稳定。调查期间整个水域的生物多样性阈值均呈现出湾西部及西北部水域较高,其余水域较低的分布特点,但不同季节其变化趋势及分布范围略有差异。枯水期多样性阈值的密集分布区出现于湾西侧的部分水域,其等级水平为3级,饵料生物多样性较好,其余水域均为2级或低于2级水平,多样性一般或较差。丰水期的分布趋势与枯水期相似,其密集区出现于湾西部和西北部的整片水域中,分布范围比枯水期大,但等级水平明显低于枯水期,为2级,多样性一般,其余大部分水域均为1级水平,多样性较差。  

Integrated assessment on the level of the food organisms in Kaozhou Bay

Supported by Geographical Information System(GIS),the level of the food organisms in Kaozhou Bay in February(dry season) and August (wet season) of 1999 was analyzed and evaluated by using the method of integrative model.In dry season the distribution of food organisms in the whole bay was even,and the dense area occurred in the northwest of the bay,the mouth of the bay and the estuary of Jilong River with the level of grade 4,representing that the food organisms were rich in these waters. In the wet season the level of food organisms varied greatly,and the dense area occurred in the middle of the bay and the coastal waters along Wangjingzhou Bay with the richest level of grade 4-5,and followed by the mouth of the bay with the level of grade 4. The comparison between the 2 cruises of survey showed that the level of food organisms in the wet season was higher than that in the dry season.The variation of the main dominant species of the food organisms showed obvious seasonal succession. The main dominant species of phytoplankton and zooplankton changed greatly in different season,while the composition of the dominant species of benthos remained steady.During the survey,the diversity index and evenness of the food organisms varied greatly with the largest ranges of 0.01-4.49 and 0.01-0.96,respectively,which indicated that the food organisms in the bay were affected significantly by the environmental condition,and the composition structure of the organism population and the level of biodiversity was unstable. During the survey,the distribution of the diversity threshold of the food organisms in the whole bay showed the characteristic of higher in the west and northwest of the bay and lower in the other waters,but the variation trend and distribution scope changed slightly in different season. In the dry season the dense area of the diversity threshold occurred in part of the western waters of the bay with level of grade 3,indicating that the diversity was well.While in the other waters the level was in grade 2 or lower,indicating that the diversity was normal or poor. In the wet season,the distribution of the threshold was similar to that in dry season with the dense area occurring in the western and northwestern waters of the bay,which was wider than that in dry season,while the level was obviously lower with the level of grade 2 in the dense area and the level down to grade 1 in most of the other waters.