Changing water quality and thermocline depth along an aquaculture gradient in six tropical crater lakes

Charlotte L. Briddon*, Sarah Metcalfe, David Taylor, Wayne Bannister, Melandro Cunanan, Adelina C. Santos-Borja, Rey Donne Papa, Suzanne McGowan

*Corresponding author for this work

Research output: Contribution to journal/periodicalArticleScientificpeer-review

4 Citations (Scopus)
14 Downloads (Pure)

Abstract

Understanding how lakes respond to changes in nutrient loading along a productivity gradient can help identify key drivers of aquatic change, thereby allowing appropriate mitigation strategies to be developed. Physical, chemical and biological water column measurements combined with long-term water monitoring data for six closely located crater lakes, in Southeast Asia, were compared to assess the response of lakes along a productivity gradient equating to a transect of increasing aquaculture intensity. Increasing chlorophyll a (phytoplankton biomass) in the upper waters appeared to modify the thermocline depth and light availability causing a shift from a deep chlorophyll maximum at low aquaculture intensity to the emergence of algal dead zones lower in the water column with high aquaculture intensity. High phosphorus loading and light limitation from enhanced algal biomass, associated with high aquaculture intensity, exacerbated nitrogen drawdown, leading to the prevalence of potentially nitrogen-fixing cyanobacteria. Seasonal overturn during the cooler season resulted in low dissolved oxygen concentrations in the epilimnion, potential harmful algal blooms, a reduction in the habitable depth for fish and ultimately increased mortality amongst farmed fish.

Original languageEnglish
Pages (from-to)283-299
Number of pages17
JournalHydrobiologia
Volume850
Issue number2
DOIs
Publication statusPublished - 2022

Keywords

  • Anoxia
  • Cyanobacterial blooms
  • Light limitation
  • Pigments
  • Southeast Asia
  • Tropical limnology

Research theme

  • Sustainable water and land use

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