This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Ongoing research is providing a clearer picture of how climate change can affect different aspects of the Coorong in South Australia—and is helping develop strong environmental strategies that can be adapted as the climate changes. One project, led by Flinders University researchers, looks at the effect of climate change on phytoplankton, including microalgae and harmful algal blooms.
The findings are published in the journal Continental Shelf Research. These microscopic, free-floating aquatic organisms absorb sunlight and carbon dioxide to produce oxygen. Although tiny, they are a key part of the Coorong's food web, as pipis, mussels, insects and small fish all eat phytoplankton.
However, some phytoplankton can also form harmful algal blooms, so Flinders researchers have investigated which phytoplankton species live in the different Coorong habitats and how water level, salinity, nutrients and temperature affect them. "This information can help us predict how climate change may impact the food web and the risk of harmful algal blooms," says research paper lead author Dr. Daniel Chilton, from Flinders University's College of Science and Engineering.
The research team sampled phytoplankton across the Ramsar-listed Coorong, from freshwater to salty habitats, to see what species—and how many—lived in which environment. These results were combined with 16 years of historical data to determine what environmental factors most influenced the phytoplankton's habitat preferences. "The 16-year data set encompasses an exceptional climate gradient, from extreme drought to flood conditions, and these flow extremes strongly shape phytoplankton communities," says Chilton.
The researchers, including experts from Adelaide University and The University of Western Australia, found that changes to salinity and water levels through variations in freshwater inputs to the Coorong had the most influence on phytoplankton abundance, diversity and community structure. Freshwater and low-brackish, or mildly salty, habitats had the most species, but these communities were dominated by cyanobacteria (including blue-green algae) and chlorophytes (green algae). Extremely salty habitats had fewer species and were dominated by diatoms and dinoflagellates in balanced numbers.
Researchers also found that while the levels of harmful bloom-forming species in the Coorong are low overall, there are more than 80 phytoplankton species capable of producing toxins. "Harmful algal bloom risk varies by species and environmental conditions," explains Chilton. "High-nutrient and low-salinity conditions can promote cyanobacterial blooms, while drought-driven, high-salinity conditions can increase the risk of harmful dinoflagellate blooms." The researchers say these results support predictive tools for climate-driven lagoon management.
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