水温升高对水体性质及水生生物的影响研究进展

Effects of Increasing Water Temperature on Water Properties and Aquatic Organisms: A Critical Review

全球变暖导致水温升高,河流、湖泊普遍升温,而这种增温趋势还将加剧。水温升高,直接导致水体稳定度提高,垂向对流减少,分层现象加剧,冰河解冻提前,水体封冻期缩短;间接导致水体溶解氧含量降低,尤其底层水体缺氧现象更加严重,底层水体缺氧导致沉积物中营养盐向上覆水的释放量增加,两者均会诱导水体发生气候变化富营养化。水温升高影响水生有机体的生物过程、物种组成及食物网变化;水体分层及溶解氧含量降低均会增加水体营养物负荷,促进水体浮游藻类种群发生变化;水温变化还会改变水生植物生长条件、生物量及分布,影响水体中鱼类的生存、生长发育,以及栖息地发生变化,使水生无脊椎动物种群数量减少。因此,水温增加势必对水生生态系统产生重要影响。

Global warming has resulted in continuously increasing water temperatures in most lakes and rivers,and this warming trend will intensify with climate change.Changes in water temperature have a significant impact on aquatic ecosystems and it is therefore important to study the influence of water temperature changes on these critically important ecosystems.In this study,we analyzed the trend of increasing water temperature and summarized the effects of elevated water temperature on the properties of water itself and on aquatic organisms.Global water temperatures have increased from 0.2℃to 2℃and will continue to increase in the future due to climate change.With increased surface water temperature,water bodies becomes more stable as thermal stratification strengthens and vertical convection weakens.Rivers and lakes freeze later and thaw earlier,shortening the time of ice cover.Further,increased water temperature reduces the solubility of oxygen,reducing dissolved oxygen,exacerbating bottom water hypoxia and increasing nutrient release from sediments.Both reduced mixing and increased nutrient release promote climate-induced eutrophication.The increase in water temperature affects biological processes,species composition and the food web structure of aquatic ecosystems.Thermal stratification of water bodies and decreased dissolved oxygen will increase nutrient loading,altering phytoplankton community structure,growth conditions and the biomass and distribution of aquatic plants.Rising water temperatures will also reduce the number of aquatic invertebrates and affect the survival and growth of fish and fish habitat.Rising water temperatures are impacting aquatic ecosystems and the impacts will become more severe.