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Response of the photosynthetic activity and biomass of the phytoplankton community to increasing nutrients during cyanobacterial blooms in Meiliang Bay, Lake Taihu
Author(s) -
Wu Pan,
Lu Yongjun,
Lu Yan,
Dai Jiangyu,
Huang Tingjie
Publication year - 2020
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.1002/wer.1220
Subject(s) - eutrophication , phytoplankton , cyanobacteria , environmental chemistry , nutrient , algae , chlorophyll a , ammonium , biomass (ecology) , nitrate , photosynthesis , algal bloom , environmental science , chemistry , biology , ecology , botany , bacteria , genetics , organic chemistry
Nutrient enrichment facilitates algal outbreaks in eutrophic shallow lakes. To further understand the influence of various inorganic nutrient forms on cyanobacterial blooms, a nitrate (NO 3 ), ammonium (NH 4 ), and orthophosphate (PO 4 ) amendment experiment was conducted in a large shallow lake of China (Lake Taihu) during summer. The results showed that the photosynthetic performance of phytoplankton responded more positively to phosphorus (P) than nitrogen (N), and NH 4 addition stimulated higher algal photosynthetic activities in P‐enriched waters. Individual inorganic N or PO 4 addition significantly activated cyanobacteria and green algae. Meanwhile, the N plus P amendment promoted higher biomass of the planktonic microbial community, and the dual addition of NH 4 + PO 4 yielded the highest chlorophyll a concentration. NH 4 additions provisionally promoted higher green algae than cyanobacteria biomass in the beginning, while cyanobacteria dominated again with increasing NH 4 :PO 4 ratios. These results revealed that increasing ammonium would enhance the increase in phytoplankton biomass in advance and prolong the duration of algal blooms. Hence, based on the control of P loading, the reduction in external inorganic N focusing on ammonium sources (such as ammonia N fertilizer) at the watershed scale would help to alleviate eutrophication and cyanobacterial blooms over the long term in Lake Taihu. Practitioner points Ammonium addition stimulated higher algal photosynthetic activities in P‐enriched waters. Individual inorganic N or PO 4 addition significantly activated cyanobacteria and green algae. The dual addition of NH 4 + PO 4 yielded the highest chlorophyll a concentration. Increasing NH 4 would enhance the increase in phytoplankton biomass in advance and prolong the duration of cyanobacterial blooms.