Seagrasses are essentially what their name implies, flowering plants which grow in the sea and appear like grass. These seagrasses can cover vast areas forming underwater meadows. In total, there are seventy-two known species of seagrass which are a vital part of the marine systems in which they are found. Amongst the many roles seagrass plays, one of them is to contribute to the health of coral reefs, marshes and mangroves.
A variety of species depend upon seagrasses for food, including manatees and dugongs-which is their primary source of food. In addition, seagrasses contribute to the food supply of sea turtles, sea horses and a variety of fish as well. Some of these same species call seagrasses their home, making seagrass also an important habitat.
Now a new study indicates that seagrasses may be vital in fighting climate change as well. According to a study recently published in the journal Nature Geoscience, seagrasses absorb more carbon than trees do comparatively on land. Trees are considered a major carbon sink on land, however, seagrasses appear to beat tree absorption levels by nearly triple.
The study determined that a square kilometer of seagrass can hold upwards of 83,000 metric tons of carbon. Comparatively, a square kilometer of forest holds approximately 30,000 metric tons of carbon. Seagrasses were determined to be responsible for at least ten percent of all carbon absorbed by the global oceans each year. In addition, the researchers determined that much like permafrost, seagrasses in many places have stored carbon for many millenniums. All of this is despite seagrasses only covering 0.2 percent of ocean terrain.
Of the seventy-two known seagrass species, fifteen are endangered, vulnerable or near threatened. Seagrasses are suffering from habitat loss, biodiversity loss and also potentially at the hands of global warming. Pollution is the main reason for declining seagrass. In addition, sedimentation is an increasing problem due to runoff which has increased alongside deforestation. Sewage and agricultural pollution are also major factors in the decline in seagrass. Largely seagrass is no longer along the coast of countries with significant pollution, such as China.