This study was initially designed to use industrial remotely operated vehicles aboard deepwater oil rigs and drillships to document the biodiversity of plankton in the waters around the MC252 accident. At the time the project was proposed, it appeared likely that access to such ROVs would be available. Subsequent demands for these systems to support the oil spill response combined with the BOEMRE moratorium on drilling permits made it impossible to secure access to any deepwater rigs within the time-frame of the project.
During the oil spill response, large numbers of oil-field support vessels were employed as ad hoc research vessels. Most were not equipped with the sophisticated electro-optical winches and cables necessary to deploy most currently-available plankton imaging systems. Moreover, none of the available imaging systems were capable of collecting images of large volumes of water to the depths of the Gulf in the vicinity of MC252 (1500 – 2000 m). Given our labs history of developing innovative plankton imaging systems (ZOOVIS) with past funding from the Office of Naval Research, we recognized a capability to design a new imaging system capable of autonomous, battery-powered operation and able to quantify the zooplankton in large volumes of water to depths of 2000 m.
With the assistance of Dr. Rudi Strickler (University of Wisconsin) who is one of the world’s experts in zooplankton imaging, we built ZOOVIS-DEEP. ZOOVIS-DEEP employs the principle of shadowgraph optics to quantify the contents of 300 ml of water 15 times per second. Thus it can sample 4.5 liters s-1 and 270 liters min-1. The system is equipped with a CTD and can accommodate additional sensors.
Tests of the system were performed in Chesapeake Bay during June and October of 2011 as a collaboration with Dr. Hongsheng Bi (University of Maryland). Even in the turbid waters of Chesapeake Bay the camera system provided images of outstanding quality and clarity. A particular strength is the system’s ability to image nearly transparent organisms such as ctenophores, medusa, and chaetognaths. This is particularly relevant to work in the deep Gulf of Mexico where gelatinous organisms predominate.
Over 432,000 images were collected during a single day of the October cruise. We are currently working with Dr. Bi and plan collaborations with Drs. Cabell Davis (WHOI), Robert Cowen (RSMAS), and Andrew Remsen (USF) to develop new software tools to rapidly process images from ZOOVIS-DEEP.