Research at the Department of Civil and Environmental Engineering of MIT suggests that aquatic plants in rivers and streams may play a vital role in the health of oceans and coastal waters.
This new understanding can be used to guide restoration work in rivers, wetlands and coastal zones by helping ecologists determine the vegetation patch length and planting density necessary to damp storm surge, lower nutrient levels, or promote sediment accumulation and make the new patch stable against erosion.
Traditionally, people have removed vegetation growing along rivers to speed the passage of waters and prevent flooding.
But, in recent years, that practice has changed. Ecologists now advocate replanting, because vegetation provides important habitat.
In addition, aquatic plants and the microbial populations they support remove excess nutrients from the water.
The removal of too many plants contributes to nutrient overload in rivers, which can subsequently lead to coastal dead zones—oxygen-deprived areas of coastal water where nothing can survive.
One well-documented dead zone is in the Gulf of Mexico, fed by nutrient pollution from the Mississippi River, which grows to be as large as the state of New Jersey every summer.