After patiently waiting for nearly a year, the Voss Lab was thrilled to finally explore mesophotic depths with the new Mohawk ROV. This exciting new tool is owned by the National Marine Sanctuary foundation and operated by CIOERT. During the latter half of the first two cruise days, the team used the Mohawk ROV to scout for specific corals species along the edges of the coral caps at 150ft. To assess the direct effects of mesophotic depths on coral biology and physiology, Michael will be conducting a reciprocal transplant experiment. Using the ROV, we were looking for potential sites with M. cavernosa at 140-160 ft. The teams were pleased to find geologically and biologically diverse ledges surrounding parts of both Flower Garden Banks, including numerous M. cavernosa that are perfectly sized for transplants. In most areas, coral cover exceeded 60% and was dominated by large plating sheets of Orbicella franski, encrusting and mountainous M. cavernosa, and boulder-like Stephanocoenia intercepta. Some of the colonies were over 9ft in diameter, meaning they are hundreds of years old. Of course, the extremely rugose structure provided by the corals hosted a diverse array of sponges, fish, and invertebrates.
In May 2015, the Voss lab hopes to return to FGB and conduct technical dives to set up the experiment. The objective is to move shallow colonies to mesophotic conditions and mesophotic colonies to shallow conditions (with spatial and procedural controls) and repeatedly sample them over the next three years. This experiment will help to uncover some of the mechanisms that allow the same coral species to survive at both shallow and mesophotic depths. Michael will analyze these samples with a variety of metrics including microsatellites, gene expression profiling, and skeletal morphometrics. From what we have seen on this cruise and previous cruises in 2010-2012, FGB appears to be an ideal location to conduct the experiment and establish monitoring of transplanted corals.