Underwater microphones will track impact of offshore wind power on marine life along the coast

October 13, 2014

Offshore wind farms will allow renewable energy to be generated with little or no carbon dioxide emissions, but little  is known about how they impact the marine species living and migrating along the coast. A new study led by the University of Maryland Center for Environmental Science will help State and Federal decision-makers better understand where whales, dolphins and porpoises occur along the coast off of Ocean City, and how they use this habitat. This information will assist in determining the best way to develop wind farms in order to minimize disruption or harm to marine life in the area.

“Determining patterns of marine mammal occurrence is a critical first step in order to determine any potential effects that offshore wind energy development might have on the behavior and ecology of resident or migratory species,” said the study’s lead scientist Dr. Helen Bailey, who has also studied the impact of wind farm construction noise on marine life off the coast of Scotland.

Offshore wind farms are key to creating a renewable energy mix in Maryland. However, potential negative impacts on marine species could include habitat loss, collision risk, and harmful effects from increased noise and electromagnetic fields.

Beginning this fall, underwater microphones will be affixed on buoys anchored to the ocean floor to continuously record sounds produced by large whales and other marine mammals. This will allow scientists to track their geographic distribution and assess their abundance, and densities along the coast. The study will collect two-years of baseline data that can be used to inform the design of wind farms, how to minimize the impact of construction noise and environmental impacts, and how to facilitate ocean planning in the area.

“A critical element of wind energy planning is developing projects in such a way that we avoid or minimize negative environmental impacts those installations may cause,” said Tom Miller, director of the University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory. “Making these decisions requires a year-round understanding of the species that frequent the area, particularly for protected species that are sensitive to sound, such as marine mammals.”

The U.S. Department of the Interior’s Bureau of Ocean Energy Management (BOEM) and the State of Maryland have facilitated the identification of areas on the Atlantic Outer Continental Shelf that appear most suitable for wind energy activities while minimizing environmental and human user conflicts, including an area of about 94 square miles approximately 10-27 miles from Ocean City, Maryland. 

The acoustic monitoring devices will record both ambient and marine mammal sounds from a broad range of sources and species. Large whales tend to vocalize at low frequencies, while dolphins and porpoises produce high-frequency echolocation clicks, as well as a variety of other sounds. These species all produce sounds that are used for critical ecological functions, such as communication, navigation, and finding food. Ambient sound, consisting of both natural and man-made sources, is an important component of marine habitats. It also determines when other sound signals may be detected by marine species, which can affect their ability to communicate and navigate.

Marine mammals are protected under the Marine Mammal Protection Act, and those that are known to occur in this region include several large whale species listed as endangered under the Endangered Species Act, such as the North Atlantic right whale, fin whale, and humpback whale. There are also minke whales and small cetacean species frequently present, such as bottlenose dolphins, short-beaked common dolphins, and harbor porpoises.

The Maryland Department of Natural Resources secured the funding for this project from the Maryland Energy Administration’s Offshore Wind Development Fund and BOEM.