St. Petersburg Coastal and Marine Science Center
Microbes are ecosystem architects! All underwater surfaces are rapidly covered by a thin layer of living things (biofilm), starting with microbes. The mixed community of bacteria in a particular biofilm can determine what other organisms will later choose to settle and grow in that spot. In this way, the microbes affect the eventual community structure of the visible fauna (things like sponges, anemones, and corals).
As part of the Mid-Atlantic Canyons work, settling plate experiments were deployed and recovered to determine what types of microbial biofilms form on different surfaces. Stacks of settling plates were made by spacing apart blocks of natural surfaces like limestone (calcium carbonate) and sandstone, as well as stainless steel (to mimic a shipwreck). These settling plates were mounted on weighted metal frames holding scientific instruments (benthic landers) that were placed on the sea floor at the head and mouth of both Baltimore and Norfolk Canyons. The experiments were deployed during our first cruise in August 2012. The settling plates in Baltimore Canyon were retrieved during our research cruise in May 2013 and the settling plates in Norfolk Canyon were retrieved during a cruise in August 2013.The objective was to leave the settling plates in place for 8-12 months to accumulate biofilms that can now be analyzed to determine their microbial composition by DNA sequencing. We will look for differences in microbial communities based on the substrate type (limestone, sandstone or steel), the depth (canyon heads vs. canyon mouths), and between Baltimore and Norfolk Canyons.