Author(s): Jiangyu Dai
Linked Author(s): Jiangyu Dai
Keywords: Water diversion eutrophic lakes phytoplankton community pulse effect cumulative effect
Abstract: Due to the allochthonous input of nutrients and species, the cumulative effects of water diversion on water receiving lakes deserve attention. Taking the Water Diversion project from Yangtze River to Lake Taihu (WDYT) as an example, we explored the temporal effects of WDYT on the phytoplankton community and physicochemical habitat of Lake Taihu in autumn and winter. Although the short-term diversion significantly increased the risk of importing nutrients, the relatively high quality of the diversion water compared to other inflow rivers had improved the water quality of the water receiving lake region. The seasonal water diversion significantly increased phytoplankton diversity and community network complexity, and reshaped the lacustrine community to be diatom-dominated with their relative proportions of 24.1% -64.9% during water diversion periods. The differences of phytoplankton diversity, community composition and physicochemical habitat in the water receiving lake region between the diversion and non-diversion years were more evident than those between the non-diversion years in the same season, with comparing the multivariate dispersion indices among them. However, the lacustrine phytoplankton community during non-diversion periods still has not been essentially altered after several years of diversion, so the pulse effects of short-term water diversion were more obvious than the long-term cumulative impacts. Better control of allochthonous nutrients, appropriate increase of inflow water, adhering to the long-term operation, should be effective to enhance ecological benefits of such water diversion projects.
Year: 2025