Humans and Estuaries

Timber Harvest

Silviculture is an important industry throughout the Southeast USA. However, this activity does entail environmental impacts, such as increased runoff, sedimentation, and reduced habitat values from degradation and fragmentation.  Click here  to watch an environmental engineer (Dr. Bill Strosnider) explain some of the human impacts of timber harvesting on a newly cleared coastal plot.

Former Rice Fields

Sometimes dramatically transformed ecosystems can become important sources of ecosystem services.  Click here  to tour a long-abandoned rice field just outside of Georgetown, SC.

These plots were abandoned and left to succession from the 1860s to 1920s, resulting in important wetland habitat and flood control capacity along the Waccamaw River. While it was unintentional, these systems deliver important ecosystem services that are different than the original bottomland hardwood forest, but increasingly important given the pace of coastal development 

Stormwater

Stormwater is a leading cause of water quality degradation in estuarine waters worldwide.  Click here  to see an especially vivid example of stormwater handling in Georgetown, SC described by an environmental engineer (Dr. Bill Strosnider). The runoff is entering from a highly urbanized watershed. The outlet of this system flows into the Sampit River, about a kilometer from Winyah Bay.

Thankfully, some of the control structures you see in the video (i.e., sedimentation pond and trash rack) reduce solid-phase pollution loading to the estuary. However, more work is needed upstream to protect our ecosystems, especially from dissolved (e.g., nutrients, metals) contaminants.

Plastics and Marine Debris

Unfortunately, discarded plastic waste products are now a ubiquitous feature of most ecosystems, and estuaries are no exception. Ranging from lost birthday balloons to plastic straws, plastic products are incredibly slow to degrade, and pose a hazard to wildlife via entanglement or consumption.

In addition, large plastic products break down into smaller and smaller particles (known as microplastics), which eventually are small enough to be consumed by wildlife. These microplastics can also serve as vectors for chemicals, pollutants, and contaminants.  Here,  we’ve highlighted examples of plastic marine debris found on a wilderness beach and barrier island.

Abandoned Fishing Gear

Another form of marine debris occurs in the form of lost, abandoned or discarded fishing gear, such as pots, traps, and nets, also known as “ghost nets” or “ghost traps”. Composed of long-lasting metals and plastic, these items are often slow to degrade, and thus can continue to ensnare and entangle both harvested species (e.g., fishes and crabs) and legally protected species such as seabirds, turtles, and marine mammals if not relocated and removed.  Click here  to see an example of a crab trap washed ashore on a wilderness barrier island. 

Derelict Vessels

A large and obvious form of marine debris in many estuarine systems are derelict or abandoned vessels (click here for an example). Whether they sunk or washed ashore during a storm, or were simply left by their previous owners, abandoned vessels are not only unsightly, but they can be a source of pollution as they degrade.

Leftover oil and fuel can leak into surrounding waters and sediments, onboard plastics will break down, and the vessels themselves can serve as a hazard to navigation and the public.  Click here  to see abandoned boats and their effects on the environment.

Fisheries and Working Waterfronts

Fishing is another important industry in the Southeast USA, and many communities have strong historical and cultural legacies of supporting fishing through vibrant working waterfronts (see here for an example).

Unmanaged harvest activities can lead to declines in estuarine habitat quality (via the destruction and degradation of fished areas) and in populations of both targeted and bycatch species. Reducing these impacts requires an integrated approach to management that balances the health of fishing communities, harvested species, and the habitats they depend on. 

Ports and Marinas

Ports and marinas, like the one featured here, provide access to and from the marine environment, but are also a source of human impacts such as pollution. This can come in the form of fuel or oil spills, discharge of cleaning-related chemicals, and through the use of anti-fouling agents such as copper and other heavy metals. In addition, highly developed waterfronts like ports and marinas involve extensive changes to natural shorelines and adjacent wetlands and uplands. 

Developed Waterfront

Human population centers are commonly situated aside water resources (e.g., lakes, rivers, bays). Developed waterfronts are common elements, especially alongside estuaries worldwide.  Click here  to see a clip of the mixed-use development alongside the docks in Georgetown, SC.

Industrial Waterfront

Heavy industry is also often sited next to large bodies of water due to transport, cooling, and/or process needs.  Click here  to see active and inactive industrial development in Georgetown, SC and learn about some of the impacts these human activities can have on estuaries. Derelict industrial settings often become dumping grounds for further solid waste.  See if you can spot anything  that might not be tolerated in a more pristine setting!

Digging Deeper

We’ve spent a day in the field with scientists highlighting examples of the influences humans can have on estuarine ecosystems. If you’re interested in learning more,  click here  for additional resources to dive deeper into the field of human impacts. 

Acknowledgements

This guided tour was developed by the  Baruch Marine Field Laboratory  at University of South Carolina,  University of Georgia Marine Institute at Sapelo Island , and  Bethune-Cookman University . This collaboration was funded by the National Science Foundation ( award #2037372 ) to develop virtual products that support marine and estuarine field science and mitigate education disruptions from COVID-19. Special thanks to Briana Moen, Kristina Johnson Strosnider, Beth Thomas, and Hayley Fournier for their assistance in collecting the footage for this module.