Identifying the Mechanisms behind the Positive Feedback Loop between Nitrogen Cycling and Algal Blooms in a Shallow Eutrophic Lake
| Autor: | Yu Yao, Ruiming Han, Limin Zhang, Dujun Li, Huaji Liu |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Denitrification
lcsh:Hydraulic engineering 010504 meteorology & atmospheric sciences Geography Planning and Development 010501 environmental sciences Aquatic Science 01 natural sciences Biochemistry Algal bloom Freshwater ecosystem lcsh:Water supply for domestic and industrial purposes lcsh:TC1-978 nitrogen cycle Profundal zone Nitrogen cycle 0105 earth and related environmental sciences Water Science and Technology lcsh:TD201-500 denitrification fungi Hypoxia (environmental) food and beverages algal blooms nitrification eutrophication Lake Taihu Environmental chemistry Environmental science Nitrification Eutrophication |
| Zdroj: | Water, Vol 13, Iss 524, p 524 (2021) Water Volume 13 Issue 4 |
| ISSN: | 2073-4441 |
| Popis: | Algal blooms have increased in frequency, intensity, and duration in response to nitrogen (N) cycling in freshwater ecosystems. We conducted a high-resolution sedimentary study of N transformation and its associated microbial activity in Lake Taihu to assess the accumulation rates of the different N fractions in response to algal blooms, aiming to understand the mechanisms of N cycling in lacustrine environments. Downcore nitrification and denitrification processes were measured simultaneously in situ via diffusive gradients in thin-films technique, peeper, and microelectrode devices in a region of intensified algal blooms of shallow lake. The decomposition of different biomasses of algal blooms did not change the main controlling factor on different N fractions in profundal sediment. However, the decomposition of different algal biomasses led to significant differences in the nitrification and denitrification processes at the sediment–water interface (SWI). Low algal biomasses facilitated the classic process of N cycling, with the balanced interaction between nitrification and denitrification. However, the extreme hypoxia under high algal biomasses significantly limited nitrification at the SWI, which in turn, restricted denitrification due to the lack of available substrates. Our high-resolution results combined with estimates of apparent diffusion fluxes of the different N fractions inferred that the lack of substrates for denitrification was the main factor influencing the positive feedback loop between N and eutrophication in freshwater ecosystems. Moreover, this positive feedback can become irreversible without technological intervention. |
| Databáze: | OpenAIRE |
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