More than 90% of the world’s salt marshes may soon succumb to sea level rise: Study

Source: The post is based on the article “More than 90% of the world’s salt marshes may soon succumb to sea level rise: Study” published in Down To Earth on 4th April 2023

What is the News?

According to research, more than 90% of Salt Marshes may soon be lost to sea level rise by the turn of the century.

What are Salt Marshes?

Salt marshes are coastal wetlands that are flooded and drained by salt water brought in by the tides.

They are found in intertidal zones along coastlines, usually in protected areas such as estuaries or bays.

They are dominated by grasses and other salt-tolerant plants such as sedges, cordgrass, rushes, and mangroves.

Salt marshes occur worldwide, particularly in middle to high latitudes.

What is the importance of Salt Marshes?

Salt marshes are essential for healthy fisheries, coastlines, and communities—and they are an integral part of our economy and culture. They provide essential food, refuge, or nursery habitat for more than 75% of fisheries species, including shrimp, blue crab, and many finfish.

Salt marshes also protect shorelines from erosion by buffering wave action and trapping sediments. They reduce flooding by slowing and absorbing rainwater and protect water quality by filtering runoff, and by metabolizing excess nutrients.

What was the research conducted on Salt Marshes?

Scientists from the Marine Biological Laboratory (MBL) have been tracking vegetative cover in Great Sippewissett Marsh in Falmouth, Massachusetts, for the last 50 years to analyze the implications of higher nitrogen levels on marsh grass species.

The study noted that increased nitrogen favoured higher levels of vegetation and accretion of the marsh surface. However, these ecosystems won’t be able to outpace submergence from global sea level rise.

Even under the conservative sea level estimates, more than 90% of the salt marshes of the world will likely be submerged and disappear or be diminished by the end of the century. 

The only choice for salt marshes then would be to migrate landward. But even this choice can be impacted by anthropogenic activities and other factors.