Scientists map sea floor off NC for potential wind energy

June 15, 2014 by  
Filed under Green Energy News

Last month, the federal government allocated funding for wind energy projects off the coasts of Rhode Island and Virginia. A wind project was recently announced in New Jersey that would construct five 5-megawatt turbines off the coast of Atlantic City. In Oregon, five floating 6-megawatt turbines will be built in water more than 1,000 feet deep.

This renewable source of clean energy is gaining popularity – and North Carolina may not be far behind.

“North Carolina reportedly has some of the best conditions for wind in the Southeast United States,” said Chris Taylor, National Oceanic and Atmospheric Administration research ecologist at the National Centers for Coastal Ocean Science lab in Beaufort. “Our proximity to the Gulf Stream promotes relatively consistent strong winds that can have the potential for producing energy if utilized in the right way.”

North Carolina coastal scientists are involved in multiple projects exploring whether our coast is a good site for wind energy development. Researchers at UNC Chapel Hill’s Institute of Marine Sciences deployed two buoys between Cape Lookout and Cape Hatteras this spring. Harvey Seim, a professor of marine sciences, said the buoys will collect information on water and atmospheric conditions in the Atlantic for one year: “The intent here is to take a closer look at what the offshore wind energy resource is like and to carefully document its structure to help where and where not to consider deployment of offshore wind turbines.”

A joint research effort to identify fish habitat and underwater resources has been taking place off the coast of Wilmington, near Cape Fear. Researchers in May conducted a 10-day cruise aboard the 187-foot NOAA vessel Nancy Foster using high-resolution hydrographic sonars to characterize reef structures and detail the topography of the ocean floor. Taylor, who was the chief scientists for this project, said the resulting sea floor maps could reveal areas off the coast that would be possible sites for wind energy development.

“For this particular mission, we’re hoping to survey about 120 benthic (sea floor) habitat stations,” he said. “And we hoped to cover 75 square nautical miles of sea floor using the hydrographic sonar.”

Only 7 percent of the sea floor along the southeast United States has been mapped with modern sonars and through hydrographical surveys. The National Ocean Service, National Marine Fisheries Service, UNC and the Bureau of Ocean Energy Management partnered for the $1.4 million dollar project, which started in 2012. In May, weather conditions were favorable to launch the data-collecting mission.

“This cruise involved a significant amount of objectives,” Taylor said. We were going to be mapping the sea floor, so we needed to make sure that our sonar and our hydrographic and survey equipment was up and running correctly.”

Researchers used high-resolution hydrographic sonars that transmit sound through the water. The sound waves reflect off the ocean bottom and return to the equipment. With the technology, they’re able to determine the depth, the texture of the sea floor, and whether it has a rocky or sandy bottom. Taylor said the hard-bottom habitats can provide critical support to important fisheries, such as snapper and grouper.

“We have a variety of sea floor types that host these benthic communities that support reef fishes that support the ecology and economies of our state,” Taylor said. “We don’t have a very accurate picture of the topography of these habitat types. We also know that some of these habitat types are different whether you move from onshore, to offshore into deeper waters or you move from north to south.”

Part of the research will be comparing the sea floor habitat data from the Cape Fear site with studies conducted off the coast of Morehead City and Beaufort. Hard-bottom habitats may be at risk from impacts related to offshore energy development. Activities such as pile driving could harm sensitive benthic plants and animals. To gauge the impact on an area that potentially be developed for wind energy projects, divers collected information on fish communities, benthic habitats and influence of sediment dynamics.

Taylor said divers are used because they can make quantitative observations such as the specific species of fish, record accurate length measurements, and describe the types of habitats where the fish live.

“A team of very experienced divers here at the NOAA Beaufort Lab … describe the organisms on the sea floor – the benthic habitats, the biological communities that are on the sea floor including the sponges, the soft corals, the algae – and then count the fish.”

In addition to deploying divers to document ocean life and habitat, scientists used a technological approach known as fisheries acoustics to get a better understanding of fish populations over a large area. Taylor said the equipment is similar to the hydrographic sonar, but instead of mapping the ocean floor it uses sound to detect the number of fish at a specific location.

The findings, especially the sea floor maps, will be used in a variety of ways. The research team is still analyzing the data.

Taylor said, “Those maps will be provided to our colleagues at the Bureau of Ocean Energy Management with the intent that they would use these maps to consider refining the potential locations where wind farms might be developed. The goal is not to disturb or create any sort of impacts on these sensitive fisheries’ habitats.”

The information from the research project at Cape Fear will be used for multiple projects: Many existing NOAA nautical charts use data collected in the 1970s and even as far back as the 1940s.

Jared Brumbaugh is a reporter/producer for Public Radio East in New Bern. This article originally appeared on the website

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