Nebraska’s endangered marshes hide remnants of a vast prehistoric sea

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Around a hundred million years ago, what is now Nebraska’s tranquil prairie was covered by a vast sea, where shark-like marine reptiles roamed. When the sea eventually retreated, it left salty rock formations in its wake, making the groundwater that gurgles from the wetlands around Lincoln, Nebraska, as salty as today’s oceans.

But a hundred years of building roads, homes, stores, and offices in and around Lincoln, a city of more than 280,000, have filled in and carved up roughly 80 percent of the marshes. It’s estimated that nearly 20,000 acres of salt marsh once existed; today only 4,000 acres remain scattered throughout the region.

“Historically, wetlands are looked at as a nuisance,” says Tom Malmstrom, the natural resources coordinator for the city park and recreation department’s Saline Wetlands Conservation Project, which formed in 2003 to restore and conserve what was left of the salt marshes.

Left intact and undeveloped, a marsh offers an important ecological benefit to humans living around it. Marshes improve water quality, meaning that what flows out is cleaner than what flows in. When polluted water enters a marsh, wetland plants trap the pollutants, which settle and attach to the muddy sediment at the bottom. Microorganisms living in wetlands can help convert chemicals like nitrates into gas that’s released into the atmosphere as nitrogen, and marsh plants store chemicals like phosphorus in their roots.

 

Supporters of the saline wetlands are scrambling to save whatever they can of the remaining marshes. Since 2003, 1,676 acres of private land have been bought for conservation, and Malmstrom says eight different initiatives have protected or restored the marshland. To restore a formerly covered marsh, dirt must be excavated and steep banks flattened. In some cases, saline groundwater must be manually pumped to the surface to restore a marsh’s original hydrology.

 

Source: https://www.nationalgeographic.com/science/2020/05/saving-endangered-salt-marsh-nebraska/