气候变暖对湖泊热力及溶解氧分层影响研究进展

气候变暖对湖泊物理、化学、生物和生态系统有着复杂而深刻的直接和间接影响,而具体影响随研究区域和水体表现不尽相同。气候变暖通过改变湖泊热力和溶解氧分层进而影响湖泊生物过程和生态系统结构与功能。从全球湖泊变暖趋势、长期缓慢气温上升、极端高温事件以及气候情景模拟等方面详细综述了气候变暖对湖泊热力及溶解氧分层影响的研究进展。研究表明,全球不同区域湖泊均存在不同程度的变暖趋势;长期缓慢气温上升和短期极端高温均会造成湖泊热力分层提前,分层结束推迟,分层时间延长,混合层和温跃层深度下降,以及热稳定性增加;相伴随的是溶解氧扩散深度和氧跃层深度明显下降,加剧了湖泊底部好氧和厌氧环境。除了这种直接影响外,气候变暖引起的流域降水、入湖物质的变化以及风速的变化也会对湖泊热力和溶解氧分层产生许多间接的影响,因此未来仍然需要更多的实验证据、经验和数值模型来验证和预测气候变暖对湖泊热力及溶解氧分层的影响。

Effect of climate warming on lake thermal and dissolved oxygen stratifications: A review

Climate warming has many complex, profound direct and indirect effects on lake physical, chemical, biological processes, and ecosystem. Overall, the response of individual lake to climate change can be very different and shows a great regional difference. Climate warming alters lake thermal and dissolved oxygen stratifications to further affect lake biological processes, and the structure and function of lake ecosystem. This study detailedly reviews the study progresses of this field including lake warming trend, the effects of the long-term slowly rising air temperatures and the extreme heat wave on lake thermal and dissolved oxygen stratifications, and the projected climate scenarios. Many studies show the lake warming with the different slopes is recorded for the globally different regions lakes. The long-term slowly rising air temperatures and the extreme heat wave will result in the earlier onset of stratification, the late mixing and an increase in the length of the thermal stratification duration. In addition, lake warming will cause the descreases of mixing depth and thermocline depth, and the increase of lake thermal stability. Correspondingly, the diffusion depth of dissolved oxygen and oxycline depth significantly decrease, which will aggravate the hypoxic and anoxic environment of lake bottom. In addition, climate warming has some indirect effects on lake thermal and dissolved oxygen stratifications through changing the rainfall, input substances of the catchment, and wind speed. Therefore, much work is needed in many research areas including experimental data evidence, empirical and numerical model to validate and predict the potential effects of climate warming on lake thermal and dissolved oxygen stratifications.