Anticipating the winds of change

A baseline assessment of Northeastern US continental shelf surficial substrates
Kevin D. E. Stokesbury, N. David Bethoney, Felipe Restrepo, Bradley P. Harris
University of Massachusetts Dartmouth School for Marine Science and Technology
First published: 25 July 2024

Background

Offshore wind energy development goals are set to bring thousands of wind turbines to the North American Atlantic coast over the next decade. Such rapid development will significantly change the underwater environment. For example, currently soft seabeds (mud, sand, etc.) will have new hard structures introduced by wind farms (towers, foundation base materials, etc.). To understand the impact of wind farm development on marine habitats, we need to gather baseline information on the current state of these underwater areas. 

What We Did

We studied the ocean floor along the East Coast of the United States using historical data. This involved using data collected from 2003 to 2019 by camera surveys from the University of Massachusetts Dartmouth School for Marine Science and Technology and marine sediment data from the United States Geological Survey dating back to 1966. We wanted to map the composition of the ocean floor before wind farm development began, so we looked at the percentages of mud, sand, gravel, cobble, shell, and rock in different areas. Then, we created maps to show where each of these types of substrate are found.

What We Found

1) Across all of the areas we mapped, sand was the dominant bottom type (found in 59% of areas), followed by mud (34%), and gravel (6%).

2) Areas slated for wind farm development had different substrate types than the rest of the continental shelf. For example, wind farm lease areas predominately had a mix of sand (99% of areas) and shell (92%) as their substrates.