Salt Marsh Secrets

Salt marshes provide valuable habitat for a variety of species.

Of all the habitats on Long Island, to me there’s no greater place to connect with nature than sloshing through the shallows and mudflats of a salt marsh habitat.

From clamming, fishing, and bird watching, the marsh reveals new pleasures with each visit. However, most marsh organisms are tiny, inconspicuous, or mysterious, and it takes time, patience, and careful exploration to discover their secrets.

Salt marshes are all around us here on the East End and are one of the most important ecosystems on the planet. Naturally situated between ocean and bay, this transitional habitat, where freshwater mixes with saltwater, is a meadow of salt-tolerant plants known as halophytes which have adapted to water levels that fluctuate with incoming and outgoing tides.

As the tide rises, high water levels carry in nutrients, which promote plant growth, especially to the dominant low-marsh plant, smooth cordgrass (Spartina alterniflora). This plant, in particular, is responsible for much of the marsh’s productivity as it is able to live where few other plants can survive. Few animals eat this plant, but many marine organisms live on it and utilize it as a nursery habitat to develop through their juvenile stages. Decaying spartina grass is broken down by microbes to form detritus that fuels the marsh and its animals. Most of the marsh animals depend directly or indirectly on detritus, which is abundant in this habitat.

The variety of snails that live in the salt marsh feed on microscopic algae that cover the marsh surface. Fiddler crabs ingest mud in order to extract the abundant detritus, while ribbed mussels, clams, and oysters are filter feeders that extract detritus from the water column. All the animals that live within the salt marsh become fair game to higher predators such as blue claw crabs, striped bass, and birds such as ospreys and herons.

Salt marshes perform many functions beneficial to human beings. As mentioned earlier, they are a major producer of detritus, which provides food for young fish, shellfish, and crustaceans, which humans rely on for commercial and recreational needs as these fish mature. In addition, salt marshes serve as a natural filtration system, breaking down many pollutants into less harmful forms. They also protect us from the velocity of waves during hurricanes and help mitigate storm surges before reaching land.

Once considered a wasteland, half of our salt marshes have been destroyed due to filling of marshes to create more space for homes, industry, and agricultural use. Once regarded as non-valuable resource, the salt marsh is now seen as essential for the survival of mankind and the wellbeing of our planet. If you take your time and soak in this wonderful landscape, you too will see that it is truly a natural oasis.

Frank Quevedo is the executive director of the South Fork Natural History Museum.

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