Florida is covered in wetlands: Are they a marsh, bog, swamp or mudflat? Find out here.

The sun rises over the marsh at Castaway Island Preserve in Jacksonville. Wetlands are one of the most productive ecosystems in the world and the topic of this month's River Life.
The sun rises over the marsh at Castaway Island Preserve in Jacksonville. Wetlands are one of the most productive ecosystems in the world and the topic of this month's River Life.

Wetlands are essential for the health of the St. Johns River. They are the kidneys of our rivers and streams. They function like a sponge: absorbing water in a time of excessive rain and releasing water during times of drought. Wetlands are critically important to flood protection.

So, what is a wetland? Wetland has been used as a term only since the beginning of the 20th century and originally only used by scientists. Others preferred to use more specific terms such as marsh, bog, swamp or my favorite when growing up: mudflats. Yes, it should surprise no one who knows me to discover that I grew up playing on the mudflats. It was only in college that I discovered they were salt marshes.

The more scientific definition of wetlands is an ecosystem that depends on constant or recurrent inundation with water and is saturated at or near the surface of the soil. In other words, it’s flooded some, if not all, of the time.

We associate most wetlands with rivers, streams or other large aquatic ecosystems. They are part of the floodplain, or drainage basins for those systems. They start in the higher elevations and eventually flow down to the ocean. But there can also be isolated wetlands. These are depressions, or low-lying areas that can retain water, most frequently from rain. Sometimes springs or groundwater seeps allow wetlands to occur.

Wetlands are among the most productive ecosystems in the world, comparable to rainforests and coral reefs. They provide habitat for countless aquatic and terrestrial plants and animals, with an immense variety of species of bacteria, protozoa, insects, amphibians, reptiles, birds, fish and mammals. All can be part of a wetland ecosystem, both connected and isolated.

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Wetlands, in fact, can almost be thought of as biological supermarkets. They produce great quantities of food, both directly and indirectly. Estuaries, along with their associated salt marsh wetlands, are the nursery grounds for 90% of commercially important seafood.

However, wetlands were once considered useless wastelands. They were thought to be disease-ridden places. Filled with mosquitoes that spread malaria and yellow fever. They were to be avoided, unless you were a kid who didn’t know any better.

Ditching, draining, filling and paving them over became the norm. The vast majority of coastal salt marshes and freshwater swamps, yes, mudflats, were destroyed. We simply did not know what we were doing.

Thankfully, that changed when Congress passed the Clean Water Act in 1972. There had been a series of alarming ecological disasters that led to its passage. The law established what was termed “jurisdiction waters of the U.S.” over navigable waters, and in turn, wetlands connected to those waters. Then in 2001, the U.S. Supreme Court expanded that jurisdiction to include isolated wetlands. The argument at the time was that even the isolated wetlands were connected in a variety of indirect ways.

And so it was, until recently when the Supreme Court overturned that earlier ruling and determined that so-called isolated wetlands were not covered by the Clean Water Act of 1972. Regretfully that change will have a huge impact on the isolated wetland ecosystems in the United States. It is not hard to imagine a return to ditching, draining, filling and paving them over again.

Here’s hoping that Congress will correct the damage done by this recent ruling. I know, hope springs eternal, but I can dream, can’t I? We now know better.

Quinton White, River Life
Quinton White, River Life

Glad you asked River Life

Are shrimp and prawns the same thing?

They are similar in appearance but are two different species. Prawns tend to be larger than shrimp and can live in freshwater. Both are decapods (have 10 legs), but prawns have pincers on three pairs of legs, while shrimp just have one that is clawed. They also have different gill structures and slightly different body shapes. Some epicureans think prawns taste sweeter, but my nod goes to our fresh Mayport shrimp tasting the best.

River Life runs the first Tuesday of each month in The Times-Union. Email Quinton White, executive director of Jacksonville University’s Marine Science Research Institute, with questions about our waterways at qwhite@ju.edu. For more on the MSRI, visit ju.edu/msri.

This article originally appeared on Florida Times-Union: Wetlands are critical to Jacksonville and Florida's rivers and streams