July 18, 2012
Synopsis of upcoming REX II presentation at NOAA Conference
MIT Sea Grant intern and Hollings Scholar Collin Perkinson will make a presentation at the NOAA Science and Education Symposium to be held July 31 - August 2, 2012 in Silver Springs, MD. Perkinson will discuss efforts to employ 3D imagery technology on the underwater robot Reef Explorer II (REX II) to survey eelgrass habitats and water quality along the coast of Massachusetts.
Eelgrass beds serve as important habitats for crabs, scallops, numerous species of fish, and other wildlife, providing them with nursery grounds and food. They also help to filter coastal waters, dissipate wave energy, and anchor sediments. The range of eelgrass along the Atlantic coast has been reduced by 90% over the past 70 years, so it is important to monitor the health and biodiversity of existing eelgrass beds.
Didemnum vexillum, an invasive non-native tunicate species, poses a severe threat to eelgrass by growing on the grass and interfering with its growth, and limiting habitat for shellfish and other species in the process. In addition, common ship mooring devices with long chains have also damaged eelgrass by scouring the sea floor, becoming entangled with the grass, and ripping it from the sea floor. To combat these threats, conservation-mooring devices have been installed in sensitive areas and new eelgrass beds have been planted.
To evaluate the extent of eelgrass damage and attempts at its rehabilitation, a team of MIT Sea Grant engineers has worked to refurbish REX II with novel technologies for this mission. This robot is a hybrid autonomous underwater vehicle (AUV) and remotely operated vehicle (ROV), combining the responsiveness of a remote vehicle with the versatility and range of an autonomous one by using a surface buoy with an antenna. The REX II team will employ the robot to survey eelgrass beds and water quality along the Massachusetts coastline by capturing 3D photographs and video of the beds and by recording CTD and optical backscatter measurements.
The purpose of this fieldwork is twofold. First, it will provide information on the extent of damage to eelgrass beds off the Massachusetts coastline due to Didemnum vexillum infestations and harmful mooring practices; and second, it will help researchers evaluate the effectiveness of conservation mooring systems and monitor the growth of new eelgrass beds planted by the state of Massachusetts. This research will contribute to the growing body of knowledge on how to maintain marine ecosystems that rely on the long-term health and sustainability of eelgrass.