Research
| Title： | Total phytoplankton abundance is determined by phosphorus input: evidence from an 18-month fertilization experiment in four subtropical ponds |
|---|---|
| First author： | Li, Yan; Wang, Hong Zhu; Liang, Xiao Min; Yu, Qing; Xiao, Xu Cheng; Shao, Jian Chun; Wang, Hai Jun |
| Journal： | CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES |
| Years： | 2017 |
| DOI： | 10.1139/cjfas-2016-0057 |
| Abstract： | There is a heated debate over the necessity of nitrogen (N) reduction, in addition to phosphorus (P) reduction, for the control of eutrophication. Whole-lake fertilization experiments and lake restoration practices in high latitudes have demonstrated that P is the primary factor regulating total phytoplankton. Recognizing the limited large-scale evidence in warmer climatic zones, a fertilization experiment was conducted in four ponds located in the subtropical Yangtze River Basin, China. Total phytoplankton abundance in a pond receiving P (+P) was similar to that in a pond receiving both N and P (+N+P). Both had higher phytoplankton than a pond receiving no additional nutrient (Control). Total nitrogen concentration (TN) in the +P pond increased with the appearance of N-fixing cyanobacteria. Total phytoplankton abundance was similar in the ponds without P addition (+N, Control), and both ponds had lower phytoplankton levels than the +N+P pond. These results showed that P, not N, determines total phytoplankton abundance and that N deficiency is offset by N fixation in subtropical lakes. This experiment supports the idea that attention should be mainly focused on P reduction in mitigating eutrophication. |
