Sunday, September 24, 2023

What is living in the estuary?

UNCW researchers seek funding to track down non-native species

Chemours and CFPUA are monitoring levels of PFAS chemicals downriver form the Chemours plant in Greenville. Pictured is the Cape Fear River near downtown Wilmington. (Port City Daily photo/Mark Darrough)
Researchers are hoping to pick up on species surveying work that started in 2005. (Port City Daily/File)

WILMINGTON — Local scientists are looking for funding to follow up on an impactful wildlife study performed 18 years ago.

Conducted in 2005, the accompanying 300-page tome established a baseline for what was living in five ports in the Southeast, including Wilmington. Some of the same scientists are now looking to do a local follow-up.

READ MORE: UNCW researchers awarded $400K grant to study seagrasses

Troy Alphin, senior research associate in UNCW’s Benthic Ecology Lab, and Martin Posey, of the university’s Center for Marine Science, are the leads on an effort to examine the Cape Fear River. Both Alphin and Posey were involved in the original work. They found 200 species living in the region: fish, crustaceans, and all varieties of critters buried in the silt and sea grasses.

“We sampled everything from fish to encrusting organisms that settled,” Alphin said. “We took cores and scrapings and deployed fish traps and trawls. We did a really broad survey, although it was really narrow in timeframe.”

Alphin said the researchers at the time didn’t necessarily think there were non-natives in the water, but no one had looked before. They found five.

Interest spurred 18 years later as colleagues in other estuarine areas started to report findings of new non-native species in the waters.

“That is the power of the baseline,” Alphin said. “Right now we can go back and we can say: ‘We didn’t find it in this earlier time period, what’s present here today?’”

The researchers are looking for funding sources for the new study. The baseline 2005 report was the result of about $400,000 dollars, and Alphin noted the price did not take into account the donated man hours from partner institutions. This time the scope is smaller: just Wilmington, though the scientists hope to survey in a larger window.

In 2005, they only had a few weeks to perform the work. Alphin described it as a shortcoming because, if the work was done over a longer period, it could have given a more comprehensive snapshot of the ecosystems as seasons changed.

As far as where the funding could come from, the 2005 study received money from the National Oceanic and Atmospheric Administration’s Sea Grant program — targeted at conservation projects.

UNCW can apply for $100,000 for this project at most, which would require a 50% local match. Traditional local funding sources for these types of projects would be the county and the ports.

Breaking the project up by community type means a lower upfront cost as opposed to the expense of the 2005 comprehensive research. It also could give researchers the ability to perform more surveys as funding becomes available.

The work will start with a smaller study on sedentary organisms — creatures that attach to hard surfaces such as hulls and bulkheads. They are ideal candidates for making transatlantic journeys.

The Lower Cape Fear River Program, a partnership managed by UNCW, mostly monitors water quality and examines the organisms living in sediment at a handful of sites. Alphin said the university is examining that sediment data for non-native species as a starting point.

Non-native species are of particular concern for ports. Hangers-on and stowaways on commercial ships arriving internationally or from other American ports have the potential to set up shop in estuaries where they did not evolve. 

One of the first points in the 2005 study is to point out that more than two-thirds of non-native species in marine areas arrived via ship.

Not all non-native species are invasive. They may not fare well in their new homes or simply coexist with little impact on natives. Alphin said the species need to be assessed on occasion because there can be new introductions and formerly identified species can become new threats.

When species do become invasive, they can have a major impact on humans. Invaders in marine environments can degrade water quality and harm commercial game fish.

The problems may not be obvious, such as the invasive starlings squawking at passersby from rooftops.

Alphin gave a couple examples. Some non-native seagrass may look normal in any marine environment, but it could misplace all the native grasses that other creatures depend on. 

The common reed, phragmites australis, is an invasive wetland plant in the area. It takes over space, forcing out plants and animals and blocking shorelines. It spreads via the wind or transfers via soil.

The Cape Fear River already contains green porcelain crabs, an invasive crustacean which has no known native range because it has spread so hastily up the East Coast. The river lies at the extreme end of the crab’s current habitat, though it may continue its conquest past North Carolina due to the phenomenon of “Caribbean Creep,” caused by climate change. It allows more species to migrate away from their native ranges near the equator to historically cooler places like North Carolina.

North Carolina lies in the warm temperate zone, meaning it can experience a mix of cold and warm weather throughout the course of a year. As temperatures rise, some tropical species, normally be kept at bay the state’s colder weather, could survive as new invaders.

The results of the studies will be shared with organizations like NOAA that track the range of invasive and non-native species as they spread across the country.

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