Researchers mapped 300 coastal lagoons along Brazil's 8,500 km coastline and found that macroalgae have been formally documented in only 11 of them. These lagoons support fisheries, cycle nutrients, and store carbon, but the lack of baseline data makes it hard to track pollution or plan conservation. The findings come from a systematic review published in Estuarine Management and Technologies, covering 48 studies from nearly five decades. Macroalgae respond quickly to changes in water quality, so they are low-cost bioindicators for coastal health. The study recorded 213 macroalgal taxa, with red algae dominating, and found that no two lagoons share more than 50 percent of their seaweed species. The authors call for targeted surveys, standardized methods, and long-term monitoring, especially in understudied regions like the Amazon coast. The research also shows a clear bias: study effort tracks lagoon size and proximity to universities, not ecological importance. Without filling those gaps, Brazil's conservation planning and protected area design will continue to operate blind. DOI: 10.3897/emt.3.186569.
