【作者】 李颖虹；

【导师】 孙松； 孙晓霞；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生态， 2012， 博士

【摘要】 本文以我国典型海湾胶州湾为研究对象，系统分析了胶州湾生态系统气象水文要素、海水化学要素和生物要素的长期变化规律，主要结论如下：1、百年来胶州湾地区气温的变化呈现波动上升趋势。升温最显著的季节为冬季，夏季温度变化的幅度极小。年平均气温的变化与太平洋年代际震荡指数（PDO）的相关性显著。胶州湾海水温度的变化趋势与气温一致，尤其是冬季。胶州湾海水盐度从1981年以来呈现下降趋势，以夏季尤为显著，表层盐度年平均变率为-0.064/年，8月份盐度的变率为-0.131/年。这一现象与渤海及北黄海近岸盐度的升高趋势相反。2、近几十年来胶州湾各项营养盐浓度都呈现增加趋势，但不同种类营养盐浓度变化的时期并不相同。氨氮浓度从20世纪80年代起逐渐升高，到2001年达到顶峰，随后几年氨氮含量开始呈现下降趋势。亚硝酸盐和硝酸盐含量从20世纪90年代之后上升趋势比较明显，尤其是2000年之后，升高幅度极为显著。磷酸盐和硅酸盐浓度的变化主要体现在90年代后期。尽管与90年代相比，胶州湾营养盐结构失衡的状态有所缓解，但胶州湾营养盐控制的重点仍然是降低总溶解无机氮的增加幅度，同时需要高度关注化肥使用量增加所可能引起的硝酸盐及磷酸盐浓度显著升高的问题。3、近20年来胶州湾叶绿素a的空间分布格局没有发生大的变化，基本上保持湾东北部和西北部较高，逐渐向湾中部、南部、湾口及湾外递减的分布规律。叶绿素a的季节规律发生了很大的变化。冬季和夏季叶绿素a浓度升高，春季和秋季叶绿素a浓度下降。胶州湾叶绿素a浓度的长期变化呈现一种波动的变化规律，波动范围为1-4.76mg·m-3。胶州湾叶绿素与初级生产力的长期变化特征主要受营养盐浓度升高和养殖贝类滤食压力的综合影响。4、胶州湾浮游植物粒级组成的总体情况为表层以小型和微型浮游植物为主；底层以微型浮游植物占绝对优势。胶州湾浮游植物的粒级组成有明显的季节变化规律，表层水体中冬季和秋季以小型浮游植物为主，春季和夏季以微型浮游植物为主。底层浮游植物分级叶绿素组成比例没有明显的季节变化，以微型浮游植物占绝对优势。近20年来，胶州湾小型浮游植物所占比例呈现逐渐升高的现象，并没有出现浮游植物小型化的趋势。5、自1981年以来，胶州湾浮游植物总量呈现增加的趋势，尤其是2000年以后浮游植物数量增加显著，以冬季最为明显。浮游植物总量的空间分布格局没有发生大的变化。胶州湾的浮游植物优势种类发生变化，近50余年来一致居优势地位浮游植物种类的有中肋骨条藻、旋链角毛藻、星脐圆筛藻、柔弱角毛藻、尖刺拟菱形藻、浮动弯角藻等，而90年代之前占据优势地位的斯氏几内亚藻、印度翼根管藻、中华半管藻等种类在2000年之后不再占有优势种地位，近5年来新的优势种类包括洛氏角毛藻、密联角毛藻、波状石鼓藻、叉角藻与梭角藻等。胶州湾浮游植物群落结构的改变与冬春季水温升高、总溶解无机氮浓度的显著升高以及不同营养盐之间比例的变化有关。6、胶州湾浮游动物生物量呈现明显的上升趋势。2001-2008年的平均生物量达到0.361g/m3，为90年代的3.54倍。浮游动物的丰度在2000年之前表现为上升趋势，2001年之后呈现波动状态，与浮游动物种类组成的变化有关。浮游动物的季节变化规律明显，已由20世纪90年代夏季生物量和丰度最高的季节变化特征转变为2000年之后春季生物量和丰度最高，夏季次之的季节变化特征。春季胶州湾浮游动物的生物量和丰度升高幅度显著。胶州湾浮游动物主要类群的长期变化结果表明，水母类和被囊类浮游动物丰度增加，尤其是水母的种类和丰度，近20呈现明显的增加趋势。桡足类和毛颚类浮游动物变化趋势不明显，呈现波动状态。更多还原

【Abstract】 The paper is focused on Jiaozhou Bay, one of our country typical gulfs. Based onthe long-term field observation and history data, the long-range changes of JiaozhouBay ecosystem were studied. The main result is as follows:The air temperature in the area of Jiaozhou Bay showed a trend of increasingwith fluctuation during the past100years. The increase in temperature was the mostsignificant in the winter and least in the summer. It was also found that there weresignificant correlation relationship between the variation of annual mean temperatureand PDO (Pacific Decadal Oscillation) index. The changing trend of the watertemperature was in consistent with the air temperature, especially in winter. Thesalinity showed a trend of decreasing since1981, especially in the summer. Thevariation rate of the surface salinity was-0.064/yr for the annual mean, and-0.131/yrin August. The changing trend of salinity was contrary to the adjacent sea area, suchas the Bohai Sea and some area of the Yellow Sea.2. Results indicated that the concentrations of all of the five kind of nutrientsshowed a trend of increasing during the last several decades. The concentration ofammonium increased gradually from1980s, reaching a peak in2001and decreasedsince then. The increasing trend of the concentration of nitrite and nitrate wassignificant from1990s, especially after2000. The concentration of phosphate andsilicate was increased mainly after1998. Although the imbalance state of the nutrientwas alleviated comparing to the1990s, it is still necessary to control the increase ofDIN. It is also important to pay attention to the dramatic increase of nitrate andphosphate concentration due to the excessive use of the fertilizer. 3. Results indicated that there was no significant change on the spatialdistribution pattern of chlorophyll a concentration during the last20years. Theconcentration of Chl a showed a decreasing trend from the north-eastern andnorth-western part to the center area, the southern part, the mouth and the outer areaof the bay. The change on the seasonal characteristics of Chl a concentration wasevident. The Chl a concentration increased in the winter and summer, but decreased inthe spring and autumn. In the long term frame, the Chl a concentration was fluctuated,ranging from1to4.76mg m-3. The long term changes of the Chl a concentration andprimary productivity were affected by the increase of nutrient concentration and thefiltering pressure of maricultured shellfish in Jiaozhou Bay.4. Results indicated that the micro-and nano-phytoplankton was the maincomposition of the phytoplankton in the surface water in Jiaozhou Bay. Thenano-phytoplankton was dominant in the bottom layer, and the percentage was higherthan90%. The seasonal change of the size composition in the surface water wassignificant, with the micro-phytoplankton dominating in the winter and autumn andthe nano-phytoplankton dominating in the spring and summer. No apparent seasonalchange was observed on the size composition in the bottom layer, and thenano-phytoplankton was the dominant component at all seasons. During the past20years, the percentage of micro-plankton increased gradually, which was thought to beaffected by the long term change of nutrient concentration and structure.5.The total abundance of phytoplankton was increasing in the Jiaozhou Bay since1981, and the increase was evident since2000, especially in the winter. No clearchanges presented in the distributional pattern of total abandance of phytoplankton.As for dominant phytoplankton species, they changed in recent years, e.g. thedominant specis included all along Skeletonema costatum, Chaetoceros Curvisetus,Coscinodiscus asteromphalus, Chaetoceros debilis, Pseudonitzschia pungens,Eucampia zoodiacus et al. in the recent fifty years, while some pytoplankton specieswhich was ever dominated before1990’s, including Guinardia striata, Rhizosoleniaalata f. Indica, Hemiaulus sinensis et al., was not dominant any more since2000.Furtermore, the new dominant species (e.g. Chaetoceros lorenzianus, Chaetoceros densus, Lithodesmium undulatus, Ceratium furca, Ceratium fusus et al.) wereappeared in the recent five years. The variation of community structure ofphytoplankton in Jiaozhou Bay was related to the increase of temperature, the clearlyincreasing concentration of total inorganic nitrogen and changes of proportion ofnutrient composition in the winter and spring.6.The biomass of zooplankton was pronouncedly increasing in recent years in theJiaozhou Bay. The average biomass was up to0.361g/m3from2001to2008, equaledto3.54times biomass of them in1990’s. The abundance of zooplankton wasincreasing before2000, then it was fluctuant after2000, which was related tovariation of zooplankton species compostion. The seasonal variation pattern ofbiomass and abundance of zooplankton indicated that they were highest in summer in1990’s while they were highest in spring, secondly in summer since2000. Results ofstudies about the long changes of key functional groups of zooplankton showed thatthe abundance of medusae and salps was increasing, especially the medusae in therecent20years. The variation of abundance of copepods and chaetognaths presentedfluctuant on this condition.更多还原