Tidal wetlands at Prime Hook National Wildlife Refuge.

Brian Gilliland

By Brian Gilliland

MILTON — Salt marshes, or tidal wetlands, don’t attract the same attention as other environmental concerns like deforestation, stormwater management or beach replenishment might since the consequences of removing them aren’t immediately or locally apparent.

“But they are good for multi-tiered reasons,” said Dr. Mollie Yacano, lead environmental scientist at Delaware Coastal Programs.

Those reasons include carbon sequestration, the removal of excess nutrients or a process Dr. Yacano calls “denitrification,” and providing habitat for plants and animals.

Carbon sequestration within the marsh occurs as follows. Plants are naturally taking up carbon dioxide as part of photosynthesis and eventually die, providing meals for microbes until sediment filters in and covers everything, burying the carbon-rich plant material.

The resulting soil becomes incredibly carbon-rich, Dr. Yacano said, and if it comes back onto the surface, the carbon would be rereleased into the environment.

“It’s really best left there. We can take core samples to see how much is in there,” she said.

Should the carbon escape sequestration, there won’t be any localized disaster like an oil spill or wildfire, but it would contribute to the overall amount of carbon dioxide in the atmosphere, a known greenhouse gas, Dr. Yacano said.

Marshes make great buffers between biospheres, as marshes are about as good at nutrient filtration as lakes and mountains are at serving as backdrops for engagement photos.

“The matter in marshes degrades at a constant rate,” Dr. Yacano said. This helps the nutrients involved from collecting too densely in any one area, which can lead to things like algae blooms, she said.

This complex process, called denitrification, involves plants and animals but results in the processing of nitrate into nitrogen gas.

Like many things in a tidal wetland, it also involves a certain amount of dead or decaying matter, but also makes it possible for these areas to be positively teeming with life.

Prime Hook National Wildlife Refuge, created specifically to protect wetlands, provides habitat to 37 types of mammals, 308 bird species, 51 kinds of fish and 45 types of reptiles and amphibians, according to the refuge.

“There’s a definite need to understand the scope of services provided by tidal wetlands,” Dr. Yacano said. “People don’t know how much life is there and how much the sediments play a role in the ecosystem.”