Abstract:It is now accepted that human-induced climate change is unavoidable. On average, global surface temperatures have increased by about 0.74 ℃ over the past 100 years with the majority of the increase (0.55 ℃) occurring over the past 30 years. Marked changes may be expected to occur in the global climate during this century. Temperature increase, although only one of several related climate changes, is the key variable of change and one that pervades almost all biological processes. All ecosystems will therefore be affected to some extent by global warming and predicting potential effects on the ecosystems is of great importance for ecology and management. Lake ecosystems are vital resources for aquatic wildlife and human needs, and any alteration of their environmental quality and water renewal rates has wide-ranging ecological and societal implications. However, lakes have always been subject to the impacts of climate change, and natural climate variations in the past have been one of the main reasons that lakes are ephemeral features of the landscape. The sediment in lakes typically has high concentrations of nutrients and organic matter, and hosts a biologically active autotrophic-heterotrophic community. Thus, knowledge of the warming effects on nutrients dynamic in sediment is in urgent need. In the present study, an indoor microcosm system was set up to explore the effects of warming on the nutrients dynamic in sediment of a hypereutrophic shallow lake, Lake Nanhu. Sieved sediment cores were incubated under laboratory conditions, the experimental temperature regimes consisted of decadal spring average of Wuhan city (18 ℃) and an elevated regime with 4.5 ℃ difference from that at baseline (22.5 ℃). The contents of orthophosphate and total phosphorus in the water under the ambient temperature of 22.5 ℃ was significantly higher than those of 18 ℃ during the middle stage of the experiment, which indicated that warming accelerated the release of phosphorus from the sediment into water and the increase of the phosphorus content in the water would further increase the eutrophication. The concentration of the nitrate nitrogen in water raise rapidly accompany with the ammonia nitrogen concentration decreasing fast in the beginning of the experiment. Nevertheless, the contents of total nitrogen in water under two different temperature conditions were not significantly different from each other. The concentrations of total nitrogen in water and sediment were continuously declining at both conditions in all the experimental phases, which may indicate the denitrification and the benthic biological absorption in this experiment system. The total phosphorus content in sediment, loss on ignition of sediment, an indicator for loss of organic matter, and the chlorophyll a in the sediments were not significantly affected by the elevated temperature in this experiment system. In conclusion, warming may profoundly affect the phosphorus dynamics, but no obvious impact on the nitrogen dynamics in sediment.