Ecosystem Services are the benefits nature provides to people. In addition to the ecosystem services previously discussed (economic, cultural, and ecological benefits), estuaries provide water filtration and habitat protection.
Salt marshes are one type of estuarine habitat that acts like an enormous filter, removing pollutants such as herbicides, pesticides, and heavy metals out of the water flowing through it. In addition to pollutants, the same water often brings with it all of the nutrients from the surrounding watershed. A watershed, or drainage basin, is the entire land area that drains into a particular body of water, like a lake, river, or estuary. The nutrients flowing into an estuarine habitat often provide for lush plant growth. For this reason, estuaries are some of the most fertile ecosystems on Earth. Yet, due to the pollutants they extract from waters running through them, they may also be some of the most polluted as well.
In the animation above, as groundwaters flow into the salt marsh from the surrounding drainage area, marsh grasses and the surrounding peat extract excess pollutants and nutrients from it. View an animation showing how estuaries serve as nature’s water filters.
Habitats associated with estuaries, such as salt marshes and mangrove forests, act like enormous filters. As water flows through a salt marsh, marsh grasses and peat (a spongy matrix of live roots, decomposing organic material, and soil) filter pollutants such as herbicides, pesticides, and heavy metals out of the water, as well as excess sediments and nutrients.
One reason that estuaries are such productive ecosystems is that the water filtering through them brings in nutrients from the surrounding watershed. A watershed, or drainage basin, is the entire land area that drains into a particular body of water, like a lake, river or estuary. In addition to nutrients, that same water often brings with it all of the pollutants that were applied to the lands in the watershed. For this reason, estuaries are some of the most fertile ecosystems on Earth, yet they may also be some of the most polluted.
Estuaries and their surrounding wetlands are also buffer zones. They stabilize shorelines and protect coastal areas, inland habitats, and human communities from floods and storm surges from hurricanes. When flooding does occur, estuaries often act like huge sponges, soaking up the excess water. Estuarine habitats also protect streams, river channels, and coastal shores from excessive erosion caused by wind, water, and ice.
Unlike economic services, ecosystem services are difficult to put a price on, but economists have developed methods for determining their value. These values are used regularly and for issues related to coastal policy and decision-making.