鄱阳湖沉积物氨基酸分布特征及其对江湖关系变化的响应

Distribution of amino acids in sediments from Poyang Lake and its response to the River-Lake relationship

选取不同水情下鄱阳湖表层沉积物,研究由于江湖关系变化导致的水位变化对鄱阳湖沉积物氨基酸含量、分布与组成的影响.结果表明:1鄱阳湖表层沉积物氨基酸含量在5.40~18.2μmol·g-1间波动,高值区域集中在'五河'入湖尾闾区和鄱阳湖入长江的湖口水域;2鄱阳湖北部湖区、'五河'入湖尾闾区、湖心区沉积物氨基酸组成相似,各氨基酸含量大小排列次序为:天冬氨酸>谷氨酸>丙氨酸>丝氨酸>赖氨酸>精氨酸>甘氨酸>甲硫氨酸>酪氨酸>异亮氨酸>亮氨酸>苯丙氨酸>苏氨酸>缬氨酸>组氨酸;3由于江湖关系变化导致的鄱阳湖枯水期提前和枯水位持续下降引起的沉积物出露时间延长和出露面积增加,致使不同高程沉积物氨基酸含量差异明显,3个湖区沉积物氨基酸含量均表现为枯水期>丰水期;3个湖区不同高程沉积物氨基酸含量差异明显,其含量变化趋势为12~13 m高程沉积物>11~12 m高程沉积物>10~11 m高程沉积物,即高程越高,氨基酸含量越高;4出露时间延长引起沉积物氨基酸含量增加,其中增加最大的为酸性氨基酸.来年进入丰水期,大规模覆水可引起沉积物氨基酸等内源氮释放量增加,将对鄱阳湖水质产生一定影响,即在一定程度上可能会增加鄱阳湖富营养化风险.

Effects of river( Yangtze)-lake( Poyang Lake) relation on the content,distribution and composition of amino acid in surface sediment of Poyang Lake from different water level areas were investigated. The results indicat: 1 The content of amino acid in the Poyang Lake surface sediments varied from 5. 40 μmol·g- 1to 18. 2 μmol·g- 1,and the areas with the highest content of amino acids were located in input area of the ' Five River' and output area of Hukou. 2 The amino acids composition of the Poyang Lake sediments were similar,and the content followed the order of Asp > Glu > Ala> Ser > Lys > Arg > Gly > Met > Tyr > Ile > Leu > Phe > Thr > Val > His. 3 The dry season came earlier and the low water level continued to decline,which is due to the change of the River-Lake relationship. This causes the time of the sediments exposure prolonged and the exposing area increased,resulting in the variation of contents of amino acids in the different elevations of sediments. The amino acids of the sediments in the whole Poyang Lake during the wet season was lower than those during the dry season. There were apparently varied contents of amino acids in the sediemnts with differentelevations,following the order of 12 ~ 13 m > 11 ~ 12 m > 10 ~ 11 m. The higher of the sediments elevation,the higher of amino acids content,which is due to different time of sediments exposure. 4 Prolonged exposure time caused the content of amino acids increased,especially for acidic amino acids. At the coming plentiful water period,large-scale watering can increase the release of endogenous nitrogen and amino acids,and thus influencing the water qualityto raise the risk of eutrophication in Poyang Lake.