Divers putting shades over experimental Elkhorn corals in Biscayne National Park

Shown here are three SCUBA divers installing shade structures over experimental Elkhorn corals (Acropora palmata) that have become "bleached," that is, lost all their algal symbionts (also called zooxanthellae) because of the summer 2023 ocean-heat wave. The corals are attached to cement blocks as part of the U.S. Geological Survey’s Coral Assessment Network (USGS-CAN) that provides data on coral-growth (calcification) rates throughout the western Atlantic. Data like these are collected to document seasonal and spatial patterns in coral growth that correlate with ocean conditions and are used to guide the management and restoration of coral species that have experienced population declines across the region. Pictured here are calcification stations located in Biscayne National Park. The shade structures could help to reduce light stress that is problematic when corals are in a bleached state (see https://www.usgs.gov/media/images/coral-shading-experiment-during-a-bleaching-event for more information).