Wetlands: the stinkiest ecosystem you never knew you needed

They smell, they’re muddy and hard to cross, and let’s be honest, they just don’t have the charm of a nice sandy beach. Wetlands certainly do not rank very  high in the aesthetics category, but the value of an ecosystem cannot be measured in beauty alone.

For one thing, many ecosystems offer what are called “ecosystem services,” and Uma Nagendra introduced us to one such service a couple weeks ago during her retrospective tour of post-Katrina New Orleans. One of the things that quickly emerged from  that story – and various stories of powerful hurricanes – is the importance of wetlands to help protect coastal cities by reducing the power of storm surges. That protective role alone makes coastal wetlands worth preserving, but I’d like to explore these environments a little further. I hope to give our readers a taste of how critically important these valuable – if smelly (thanks to plenty of sulfide) – ecosystems are. Most of what you will read applies to all wetlands, but we will focus especially on one of Georgia’s most treasured natural resources: salt marshes.

Salt marshes are hands down some of the most productive ecosystems on earth. All this productivity means that massive amounts of carbon move into salt marshes from the atmosphere in the form of new plant matter, and this carbon usually ends up being buried in the sediment that builds up on the marsh platform. Just like trees in forests and jungles help combat climate change by removing excess carbon dioxide, wetlands remove carbon dioxide as well, but in overdrive.

Much of this fantastic productivity is powered by the nutrients that are carried in the water bodies that wetlands typically border (1). This means that everyone living in the surrounding areas can influence what happens in these wetlands. The waste that Athens produces travels down the Oconee, which trickles into the Altamaha River and then eventually the South Georgia coast, supporting some of the most diverse and ecologically valuable bits of coastline in the Eastern US. Of course, in nature there is such a concept as too much of a good thing like nutrients, and that brings me to another crucial service wetlands provide: filtering.

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Because they form at the margins of land and water , wetlands serve as a gatekeeper between these two environments (2). These critical transition zones perform a number of essential functions – such as carbon burial as described above – that control how nutrients move from the land to the ocean. One especially important nutrient that moves through wetlands is nitrogen.

Nitrogen is one of the more important elements in the ocean because it is a limiting nutrient, meaning that its availability controls how much plant and algae life can grow. It can also lead to a process called eutrophication, which is when SO MUCH plant and algae life grows that those organism starve themselves and start to decay. When this happens, all the oxygen starts to get sucked out of the water, leading to an ecological tragedy called a dead zone. This is when the amount of oxygen in water drops so much that aquatic life like fish and shrimp can no longer survive. Not cool.

Human activity, especially the production of fertilizers containing nitrogen, now leads to over 2 BILLION pounds of nitrogen ending up in the coastal oceans.

This is can be very bad for the economy, too. The shrimp and fish industries off the Gulf Coast and Chesapeake Bay have been hit especially hard by the death of their target critters due to the lack of oxygen (3). This is where wetlands come into the picture. Human activity, especially the production of fertilizers containing nitrogen, now leads to over 2 BILLION pounds (or just about 3,000 747s’ worth) of nitrogen ending up in the coastal oceans (4), and all of that nitrogen flows through wetlands. Yikes!

But the good news is that those wetlands will act like a giant filter, removing the nitrogen before it can cause harm to the ecosystem as a whole.  A great example of a wetland doing just that sort of filtering can be seen  by going on a short hike through the Georgia Botanical Garden here in Athens.

Unfortunately, the importance of wetlands was not well understood until ecosystem science became a mainstream topic of study. By the way, the very first proponents of ecosystem ecology worked right here at UGA. Wetlands worldwide were drained or filled in to make way for development, because we didn’t yet know how important they were or how they protect our coasts. Thankfully, those attitudes have changed and wetlands are now protected in most states.

They may not smell good, and they may not have the appeal of a long, sandy beach, but we need wetlands. It just goes to show: true beauty isn’t just skin (or mud) deep.

About the Author

Tommy Dornhoffer is an Arkansas transplant who moved to Athens six years ago to pursue his PhD in Marine Sciences, which he is planning to finish the Fall 2015 semester. He studies benthic ecology and modeling with Dr. Christof Meile, and hopes to turn his expertise towards conservation and outreach after graduation. In those rare moments he is not in the classroom or the lab, Tommy is an avid musician and played trombone with the Athens Symphony Orchestra for the entirety of his time at UGA.  More from Tommy Dornhoffer.