Studying Seafloor Erosion in the Florida Keys

Studying Seafloor Erosion in the Florida Keys

The challenge:

• In addition to their cultural, ecologic, and economic value, reefs aid in coastal protection by breaking waves away from shore and reducing coastal flooding.
• Florida’s reefs are eroding by ~5mm per year.
• The Keys have lost 44 million cubic meters of seafloor volume since the 1930s - the size of 44 Empire State Buildings.
• Erosion will result in greater increases in water depths than projected from sea-level rise alone.
• Understanding seafloor erosion will help improve coral reef restoration efforts.

Yates, K. K., Zawada, D. G., Smiley, N. A., and Tiling-Range, G.: Divergence of seafloor elevation and sea level rise in coral reef ecosystems, Biogeosciences, 14, 1739–1772, https://doi.org/10.5194/bg-14-1739-2017, 2017.

The role of the U.S. Geological Survey (USGS):

• Using a towed device and divers to collect thousands of overlapping photos.
• Creating full-color 3D maps and digital elevation models of the seafloor and reef.
• Modeling coastal flooding and hazards of reef-lined coasts including future sea-level rise projections.
• Track progress of reef restoration initiatives.
• Repeat surveys allow for tracking seafloor elevation change through time.
• Fine-scale resolution allows tracking growth or erosion of individual coral colonies.

The SQUID-5, or Structure-from-Motion Quantitative Underwater Imaging Device with 5 cameras, was developed by USGS to be towed on the water’s surface to create 3D maps of the seafloor and reefs beneath it.

The USGS created a photo orthomosaic and digital elevation model of Looe Key Reef in summer 2021. Repeat surveys will allow scientists to track seafloor elevation change through time.

USGS is creating full-color 3D maps and digital elevation models of the seafloor and reef to assist with monitoring the progress of coral reef restoration initiatives.

U.S. Geological Survey

U.S. Department of the Interior

www.usgs.gov/cmhrp

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.