Benthic community patterns

Exploring how benthic organisms are spatially distributed on coral reefs, how these patterns reflect the biology of the organisms and their interactions with their physical environment, and how changes in the abundances of different organisms occur over time across the reef landscape.

Through our research, we are revolutionizing the way in which we study and think about coral reef benthic dynamics (how organisms living on the seafloor change through both space and time). In collaboration with researchers at the University of Miami, we are using state-of-the-art digital imaging and image recognition software to form high-resolution photographs of the reef floor. These biological maps (or benthic mosaics) provide an interactive view of the reef, allowing us to track the fate of individual organisms, their battles for space on the reef floor with each other, and changes in their abundance patterns across a reef landscape. With this we are able to gain an explicit understanding of the rules that govern reef dynamics over space and time.

Benthic community patterns

Benthic mosaic images (center), collected from sites around Palmyra Atoll (left), are viewable at high millimeter resolution (right).

The team has established several long-term monitoring plots at Palmyra that we survey annually. These plots range in size from 100 to 200 m2, and cover different reef habitats (e.g the reef terrace and fore reef) across various depths (5 to 30 m). Data are collected from the high-resolution benthic mosaic images by experts who identify which organisms are present and map their distributions across the reef. By comparing the images from the same place that are collected at different times, we are able to document overall change, and—more importantly—which organisms contributed most to this change. In a way, we are tracking the battles between organisms living on the seafloor, documenting who are the winners and losers under different conditions. To date, our results have completely revolutionized the way in which we think about benthic battles on the reef floor and how the benthic community responds to external physical drivers, such as waves.

The Benthic Community Patterns team plays a central role in RTI by providing data the composition of the coral reef community, and how it changes across space and time. We use the benthic mosaic images as a basis for understanding how driving forces like herbivory and physical oceanography combine to affect coral reef health over time.

This research is being led by Dr. Stuart Sandin, whose team includes Dr. Gareth Williams, Dr. Jennifer Smith, and Clinton Edwards at Scripps Institution of Oceanography, University of California (San Diego). In addition, the team collaborates with Dr. Art Gleason from the University of Miami.