More than 100 shallow freshwater lakes stretching over 1,000 kilometers along southern Brazil and Uruguay could become an unusually powerful natural laboratory for studying climate change, pollution and ecosystem resilience. The lakes span strikingly different conditions, from relatively clear waters to nutrient-rich systems affected by cities, agriculture and wastewater, while the region is also exposed to floods, drought and strong El Niño-related climate variability. Researchers want to establish an internationally coordinated monitoring network using water chemistry, environmental DNA, microorganisms and satellite observations to track how subtropical freshwater ecosystems respond to rapid environmental change. A vast chain of shallow lakes stretches along the Atlantic coast of southern Brazil and Uruguay, forming one of the largest freshwater systems of its kind on Earth. For years, this landscape remained largely overlooked by scientists. New research now suggests that these lakes could become one of the most important natural laboratories for understanding how climate change and human activity reshape freshwater ecosystems. The study marks the first comprehensive effort to examine the Southern American Coastal Shallow Subtropical Lakes. Researchers say …