Keeping a watch on seaweeds: the forests of the world’s coasts

Macroalgal assemblages are highly productive and biodiverse ecosystems providing important functions and services, including provision of nursery areas, human food resources, and protection from coastal erosion. Macroalgal assemblages are vulnerable to global threats such as ocean warming and acidification and to other anthropogenically mediated stressors, including habitat degradation, eutrophication, pollution, overfishing, and invasive species. Macroalgal cover and composition were identified as an “essential ocean variable” in recognizing that the condition of macroalgal assemblages provides an important indicator of coastal ecosystem health. Proper baseline data and sustained monitoring are essential to detecting changes in these communities at global scales.