气候变暖造成的营养错配(mismatched nutrition)使太湖河蚬种群丰度下降吗？

It has reached a broad consensus that cyanobacterial bloom was caused in advance by global warming, which as a phonological phenomenon might lead to the mismatch of nutritious relationship between aquatic filter-feeders and phytoplankton. Lake Taihu is undergoing the global warming when the population density of the advantaged species of large filter-feeder benthos named Corbicula fluminea, has sharply decreased over the past 20 years. Therefore, a scientific hypothesis was proposed that cyanobacteria were not a suitable food for Corbicula fluminea. The advanced eruption and extensive duration of cyanobacterial bloom restrained the growth and reproduction of Corbicula fluminea; The unbalance of Corbicula fluminea’s energy happened under high temperature, so the growth and population development of Corbicula fluminea were inhibited. In this study, the effects of cyanobacterial bloom and the increasing temperature and their interaction on the growth of Corbicula fluminea were analyzed through a series of controlled experiments and combining with in-situ observation of Lake Taihu, the mechanism of decreasing abundance of species of Corbicula fluminea was revealed from a new perspective. Therefore, this study not only deepen the understanding of the influence of climate changes on the nutritious relationship in the aquatic ecosystem, but also enrich the research content of match or mismatch hypothesis.

气候变暖促进富营养浅水湖泊蓝藻水华尤其是微囊藻水华的提前暴发与持续发生已取得广泛共识，这一物候现象可能导致水生滤食动物与浮游植物之间营养关系的错配。太湖也正在经历气候变暖，湖内大型滤食性底栖动物优势种—河蚬种群丰度二十年来急剧下降。针对这一现象提出本项目科学假设：蓝藻（主要是微囊藻）不是太湖河蚬适宜的食物，蓝藻水华的提前发生与持续时间延长使河蚬生长、繁殖受抑制，加之高温季节还造成河蚬能量收支失衡进一步抑制了河蚬生长发育。项目拟通过系列受控实验同时结合湖泊原位观测，分析不同质量食物对河蚬生长与繁殖的影响，并验证高温季节是否存在由于食物质量低劣造成河蚬能量失衡进而抑制其生长的现象，从全新角度来揭示太湖河蚬种群丰度下降的机理。因此，本研究不仅可加深水生态系统中营养关系对气候变化响应的理解，还可丰富匹配/错配假说的研究内容及其在水生态系统中的应用。

太湖河蚬种群丰度下降的影响因素众多，气候变暖导致的水生滤食动物与浮游植物之间营养关系的错配，也许是其因素之一。按照计划任务书要求，完成了升温与不同质量食物对河蚬摄食率等的影响、高温季节河蚬能量收支失衡的生长验证研究、不同质量食物对河蚬生长影响的研究、以及具有不同质量食物史河蚬的繁殖特性研究。同时，在食物质量对河蚬生长影响研究方面，考虑到太湖的风浪大、底泥悬浮强烈的特征，还增加了悬浮物浓度因素；在不同质量食物史河蚬生长与繁殖特性研究方面，还增加了河蚬内脏团的转录组和代谢组，以及河蚬肠道微生物群落和功能富集机理研究，从而丰富了本项目的研究内容，加深了对科学问题的揭示。项目通过系列受控实验与原位实验研究，验证了项目提出的科学假设—气候变暖促进蓝藻在浮游植物中比例升高，蓝藻不是河蚬适宜的食物，营养错配造成河蚬生长繁殖受抑制，加之在高温季节由于能量收支失衡还进一步抑制河蚬生长，从而造成太湖河蚬种群丰度的下降。研究结果从全新的角度揭示了太湖河蚬种群下降的机理。