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Mao Z, Gu X, Cao Y, Luo J, Zeng Q, Chen H, Jeppesen E. Pelagic energy flow supports the food web of a shallow lake following a dramatic regime shift driven by water level changes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:143642. [PMID: 33302070 DOI: 10.1016/j.scitotenv.2020.143642] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/04/2020] [Accepted: 11/08/2020] [Indexed: 06/12/2023]
Abstract
Across the globe, lake ecosystems are exposed to a variety of human disturbances. A notable example is shallow lakes where human-induced eutrophication or water level fluctuation may result in a switch from a clear-water, macrophyte-dominated state to a turbid, phytoplankton-dominated state. Yet, few investigations have described synchronous changes in biotic assemblage composition and food web framework under such a shift between alternative states. We used stable carbon and nitrogen isotopes to test the extent to which switching from macrophyte to phytoplankton dominance in Lake Gucheng, triggered by a water level increase, would alter ecosystem structure and change the basal resources supporting the food web. We found that invertebrates and fish compensated for a reduction of macrophyte and epiphyte resources by deriving more energy from the alternative pelagic energy channel, where benthic invertebrates act as crucial links between primary producers and higher consumers by transporting δ13C-depleted pelagic algae to the benthic zone. Although consumers can respond to large shifts in energy allocation and stabilize food web dynamics through their ability to feed across multiple energy pathways, our study suggest that energy subsidies may promote trophic cascades and enhance the stability of the turbid regime.
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Affiliation(s)
- Zhigang Mao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiaohong Gu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaiyin 223300, China.
| | - Yong Cao
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, IL 61820, USA
| | - Juhua Luo
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Qingfei Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Huihui Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Erik Jeppesen
- Department of Bioscience, Aarhus University, Silkeborg 8600, Denmark; Sino-Danish Centre for Education and Research, Beijing 100049, China; Limnology Laboratory, Department of Biological Sciences, Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara 06800, Turkey; Institute of Marine Sciences, Middle East Technical University, Mersin 33731, Turkey
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