Over 100 South American lakes could become climate-change early-warning observatories

More than 100 shallow lakes along the Atlantic coast spanning southern Brazil and Uruguay could become vital natural laboratories for studying climate change impacts on freshwater ecosystems, according to an international research team. The study, published in the journal One Ecosystem, reveals these subtropical lakes offer a unique opportunity to monitor biodiversity, water quality, pollution levels, and ecosystem resilience in a rapidly changing world.

Lead author Mariana Kluge from Sweden's SLU emphasizes that these lakes fill a critical gap in global freshwater research, allowing scientists to test ecological theories under diverse environmental conditions while gaining insights into how subtropical freshwater ecosystems respond to climate change and human pressures. The lake network, one of the largest continuous coastal shallow-lake systems on Earth, faces numerous environmental challenges, including eutrophication, pollution from agriculture and wastewater, emerging contaminants like pharmaceuticals and microplastics, and extreme rainfall events.

Researchers argue these lakes can serve as "sentinel ecosystems" that provide early warning signs of environmental change through microbial ecology, environmental DNA analysis, remote sensing, and long-term ecological monitoring. The goal is to establish an internationally coordinated monitoring network that benefits South America and enhances understanding of freshwater ecosystems globally.

The research, resulting from an international workshop, identifies four lake regions as ideal sites for coordinated long-term observation, potentially informing global strategies for biodiversity preservation, water management, and resilience to environmental change.