| 论文摘要： |
Algal dominance between phytoplankton and epiphyton plays an essential role in predicting shallow lake shifts between clear-water and turbid-water states. However, compared to resources competition, studies on algal life-form shifts between phytoplankton and epiphyton have traditionally received less interest, as few studies have focused on algal communities in both habitats concurrently. We conducted a 4 x 3 factorial design microcosm experiment to explore the mutual feedback relationship between phytoplankton and epiphyton. The initial algal life-form (epiphytic algae and phytoplanktonic algae alone or together) and nutrients enrichment (ambient, enrichment with N and P alone or together) were manipulated. After 28 days of incubation, the results suggested that the nutrient effects on the phytoplankton and epiphyton communities differed among the three different initial algal life-forms. A significant competitive advantage of phytoplankton was found even in treatments containing only epiphytic algae as the initial algal community. The contribution of nutrient enrichment to phytoplankton abundance (13%) was similar to that of epiphyton abundance (11%). In the mutual influence between two algal communities, epiphyton was likely to be a beneficiary as the phytoplankton community contributed 15% of the variance in epiphyton abundance. In addition, significant algal life-form shifts between phytoplankton and epiphyton only occurred in treatments containing one algal life-form, but not in treatments containing both algal life forms at the beginning of the experiment. Our results emphasized the competitive advantage of phytoplankton in utilizing nutrient resources in the water column of shallow lakes. Moreover, we demonstrated that algal life-form shift was an adaptive behavior closely correlated with environmental variation. These results will provide broader insights to explore algal succession between phytoplankton and epiphyton in shallow lakes. To better understand the mutual influence mechanism between two algal life-forms under different nutrient conditions, research on multiple short time-scales based on algal migration is needed in the future. (c) 2021 Published by Elsevier B.V. |
