Overview

The fourth webinar in the “Learning as We Go” series, an ongoing forum for information exchange on offshore renewable energy topics, focused on the food web in the environment of wind farms. Presentations and dialogue described the structure and connections of marine food webs, explored change both in terms of immediate offshore wind farm vicinity and the broader regional area, and pointed to the need for continued learning via science and policy. This fourth webinar served as part of the annual Ronald C. Baird Sea Grant Science Symposium. 

Welcomes were provided by Avi Mallinger, Associate Director of Strategy + Impact at Innovation Studio, host organization for the webinar series, and by program organizer Jennifer McCann, Director of U.S. Coastal Programs at the University of Rhode Island Coastal Resources Center, and Director of Extension for Rhode Island Sea Grant. McCann said the webinar series is helping answer the collective question of “what do we need to know?” with regards to offshore renewable energy topics, and indicated the material is assisting with real-life situations, such as farm siting discussions for the Gulf of Maine. 

McCann then introduced a slate of participants with specific roles for the webinar: Carrie Cullen-Hitt, Executive Director of National Offshore Wind Research & Development Consortium, encouraged attendees to consider the organization’s resources and funding tools and programs for supporting offshore renewable energy-focused projects; Elizabeth T. Methratta, Fisheries and Wind Scientist of the National Oceanic & Atmospheric Administration (NOAA) National Marine Fisheries Service/Northeast Fisheries Science Center, served as moderator; George Maynard, Policy and Research Coordinator, of the  Cape Cod Commercial Fishermen’s Alliance, and Dave Stevenson, Fishery Management Council Coordinator of the Habitat and Ecosystem Services Division, NOAA, provided responses to the presentations; and Jennifer Dannheim, Researcher of the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (Germany) and Andrew Gill, Principal Scientist of the Centre for Environment, Fisheries, and Aquaculture Science (United Kingdom), gave the two program presentations on offshore wind turbines and the food web.

Presentations

The researchers split the discussion; Dannheim spoke about food webs in terms of the bottom part of the water column and the seabed – the lower trophic level – while Gill addressed web issues from the upper part of the column – the higher trophic level.  Taken as a whole, the work approached turbines as artificial reefs, exploring how our manmade structures alter the dynamics of complex food webs serving many kinds of animal species and ecosystem processes. As the animals within these webs support human-focused activities, such as recreational and commercial fishing, data are needed to explain not only how offshore wind farms change animal life within immediate farm sites, but whether change is registered on a regional scale, and how behavior alterations on our side – such as if fish trawling can’t take place in farms – impact the webs. 

Comparing sensitive webs to many-pieced Jenga puzzles, Dannheim described the research she and her team have carried out concerning how energy is transitioned throughout the food web associated with the seabed and the bottom of the water column; animals eat, are eaten, live, breed, and die, and these activities make up quantifiable energy transactions within webs. These transactions are scientifically complex and support current understanding of changing habitat in the immediate area of turbines: the benthos, or seabed ecosystem, is enriched with organic matter as animals, such as mollusks, grow on the parts of the turbines that are underwater, and other animals are drawn to feed on them or find refuge.  More study is needed, said Dannheim, so we can continue to learn about energy exchange in the food webs in the immediate area of turbines, as well as start to understand the even greater complexities of regional food webs. 

Gill then spoke about web dynamics in the upper part of the water column, which is the habitat for many of the fish species caught via commercial or recreational fishing. Again, Gill said, food web makeup and/or function could potentially shift on the eastern seaboard of the United States, should it be difficult or impossible for trawlers to navigate multiple farms. “What happens if there are lots of farms? What would be the impact on the food web if fishing stops? These are the sort of questions regarding regional scale of effect that we need to be thinking of, in terms of the changes in the food web,” he said. 

Gill indicated that gaining a solid understanding of the specificities of ocean food webs will be important for creating a baseline of information that can then be used to monitor change as economic development alters the ocean environment. “It’s not only the windfarms here; we need to be thinking about existing structures and other kinds of emerging technology in the ocean,” he said. 

Finally, Gill highlighted that emerging data on food webs at turbine sites stand to be critical for informing policy – economic, environmental, and societal – that could guide how people around the world make use of, protect, and enhance a wide variety of ocean resources, including fish stocks. 

Both Maynard and Stevenson asked questions of the researchers concerning the extent to which the expansion of wind farm siting could impact the stocks, and Dannheim and Gill indicated that much more work will be needed to understand large scale impact. “We need to get at the connectivity issues, what happens at this larger scale,” said Gill. “The data we are collecting now is a step towards this.” 

At the end of the presentations, McCann thanked all attendees, and shared the date of the next webinar, Tuesday, October 20, 2020 from 9:00 – 10:30 a.m. via Innovation Café. “People are continuing to ask for these and we will be surveying our audiences for topics that they want to learn about.”