Like other plants, seagrasses need light for photosynthesis, but excess turbidity reduces light penetration, while nutrient loading encourages algal overgrowth that smothers seagrass.
Measures such as gill planting or blocking upland drainage channels have helped reduce impacts on rivers by slowing flow rates and decreasing sediment and nutrient loadings.
Mangroves anchor the edges of the world, but they are slipping away, thanks to coastal development, pollution, over-harvesting, nutrient loading, overuse of freshwater, and climate change.