Ecosystem anthropogenic enrichments enhance Chroococcus abundance and suppress Anabaena during cyanobacterial-dominated spring blooms in the Pengxi River, Three Gorges Reservoir, China

Amechi S Nwankwegu; Guanglang Yang; Lei Zhang; Deti Xie; Okugbe E Ohore; Oluwafemi Adewole Adeyeye; Yiping Li; Xuexing Yao; Zenghui Song; Muhammad W Yonas

doi:10.1016/j.marpolbul.2023.115141

Ecosystem anthropogenic enrichments enhance Chroococcus abundance and suppress Anabaena during cyanobacterial-dominated spring blooms in the Pengxi River, Three Gorges Reservoir, China

Mar Pollut Bull. 2023 Aug:193:115141. doi: 10.1016/j.marpolbul.2023.115141. Epub 2023 Jun 8.

Authors

Affiliations

¹ College of Resources and Environment, Southwest University, 1 Tiansheng Road, Beibei District, Chongqing 400716, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400716, China; College of Environment, Hohai University, No.1 Xikang Road, Gulou District, Nanjing 210098, China.
² College of Resources and Environment, Southwest University, 1 Tiansheng Road, Beibei District, Chongqing 400716, China.
³ College of Resources and Environment, Southwest University, 1 Tiansheng Road, Beibei District, Chongqing 400716, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400716, China. Electronic address: zhanglei@uwindsor.ca.
⁴ College of Resources and Environment, Southwest University, 1 Tiansheng Road, Beibei District, Chongqing 400716, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400716, China.
⁵ Institute of Marine Sciences, Shantou University, Shantou 515063, China.
⁶ College of Environment, Hohai University, No.1 Xikang Road, Gulou District, Nanjing 210098, China.

PMID: 37295313
DOI: 10.1016/j.marpolbul.2023.115141

Abstract

Taxa-specific responses to the increasing anthropogenic eutrophication offer promising insights for mitigating harmful algal blooms (HABs) in freshwaters. The present study evaluated the HABs species dynamics in response to the ecosystem anthropogenic enrichment during cyanobacterial-dominated spring HABs in the Pengxi River, Three Gorges Reservoir, China. Results show significant cyanobacterial dominance with a relative abundance (RA = 76.54 %). The ecosystem enrichments triggered shifts in the HABs community structure from Anabaena to Chroococcus, especially in the culture involving iron (Fe) addition (RA = 66.16 %). While P-alone enrichment caused a dramatic increase in the aggregate cell density (2.45 × 10⁸ cells L^-1), the multiple enrichment (NPFe) led to maximum biomass production (as chl-a = 39.62 ± 2.33 μgL^-1), indicating that nutrient in conjunction with the HABs taxonomic characteristics e.g., tendency to possess high cell pigment contents rather than cell density can potentially determine massive biomass accumulations during HABs. The stimulation of growth as biomass production demonstrated by both P-alone and the multiple enrichments, NPFe indicates that although P exclusive control is feasible in the Pengxi ecosystem, it can only guarantee a short-term reduction in HABs magnitude and duration, thus a lasting HABs mitigation measure must consider a policy recommendation involving multiple nutrient management, especially N and P dual control strategy. The present study would adequately complement the concerted effort in developing a rational predictive framework for freshwater eutrophication management and HABs mitigations in the TGR and elsewhere with similar anthropogenic stressors.

Keywords: Anabaena; Chroococcus; Eutrophication; Harmful cyanobacterial blooms; Pengxi River.

MeSH terms

Anabaena*
China
Cyanobacteria*
Ecosystem
Eutrophication
Harmful Algal Bloom
Nitrogen / analysis
Rivers

Substances

Nitrogen