Fig. 1. The Lophelia II 2008: Reefs, Rigs, and Wrecks expedition consists of two segments and follows cruise specific tracks. Here we see the track from the first leg (shown in green); and the proposed track for the second leg (red). Click image for larger view and image credit.
Mission Plan
Erik CordesChief Scientist — Lophelia II 2008
Assistant Professor
Temple University
The goal of Lophelia II 2008: Reefs, Rigs, and Wrecks is to discover and characterize new deep-water coral sites in the northern Gulf of Mexico from 300- to 3,000-meter (m) depth. This is the second Minerals Management Service (MMS) funded project of its kind. The first project resulted in the discovery of several new sites; included the first quantitative sampling and experiments on Lophelia pertusa from the Gulf; and greatly increased our understanding of coral distribution. In particular, the largest known coral site in the northern Gulf of Mexico, Viosca Knoll (VK) 826 (fig. 1), was established as our main site and was preliminarily characterized. Our work, however, was far from done! The current study expands on the accomplishments of the first project by exploring a number of new areas of the northern Gulf; further characterizing the communities at the known sites; and increasing our knowledge of the biology, ecology, and connectivity of the coral populations of the Gulf of Mexico.
Our study is part of an increasing number of scientific investigations of deep-water coral communities that are resulting from the expansion of human economic interests and their impacts on the deep sea. In the deep Gulf of Mexico, the primary human economic interest lies in the abundant oil and gas reserves. Our key goals during this Lophelia II study include discovering and characterizing the deep-water coral communities in areas of current industry activity, or areas of possible activity in the future. By investigating these communities now, we have the opportunity to learn about them before extensive human impact takes place. This will create a baseline so that we may evaluate future impacts against the current, natural state of these communities.
Fig. 2. The hard coral Lophelia pertusa and some invertebrate associates from Viosca Knoll 826 at 500 m (1,640 ft) depth. Click image for larger view and image credit.
Fig. 3. A gorgonian bamboo coral, Keratoisis sp., from 1,410 m (4,626 ft) depth in Green Canyon 852. Click image for larger view and image credit.
The scientists on this cruise come from a number of different institutions and agencies, and they will be working together to explore these new sites. We will depart from Gulfport, Mississippi, and head to the central Viosca Knoll site to make a few collections. We will primarily target the hard coral Lophelia pertusa (fig. 2) as well as key species of gorgonians (sea fans and sea whips) and antipatharians (black corals) (fig. 3) so we can begin our genetic sampling and work on our methods for keeping these corals alive on board.
We will then visit a series of new sites, most of which have never been directly observed. At each site, we will begin with a series of long photographic transects to identify the high-density coral communities that we will focus on in future years (if they are still there). If we discover any corals during these surveys, we will stop and take some up-close photographs for identification and obtain discreet samples for our genetic studies of species identification and genetic connectivity. This will give us a chance to work on the samples back in the lab before our more extensive sampling in future years. When we discover extensive coral sites that we want to revisit, we will deploy large markers with temperature probes on the sea floor This will give us a record of the conditions at the site during the rest of the year (when we aren’t there).
If we discover any sites where there are no corals, we will still be gathering valuable information. To understand the appropriate conditions for coral colonization and growth, researchers need to know the conditions at sites that appear suitable, as well as where the corals are not growing. The remotely operated vehicle (ROV) is equipped with sensors that will give us information on temperature, salinity, dissolved oxygen concentration, pH, turbidity (a measure of how much material is suspended in the water), and fluorescence (a measure of how much of the suspended material is plant material from the upper depths of the ocean or land). So even when we “strike out” and don’t find any corals, we are still collecting valuable data that will improve our understanding of coral distribution.
Towards the end of the cruise, we will spend another three-to-four days at the Viosca Koll site. Here we will make additional collections of Lophelia pertusa to bring back to our laboratories and take additional tissue samples for genetic work. During this time — while we are at one site and not transiting between sites — we will also conduct multibeam bathymetric (depth) surveys, which will give us a fine-scale picture of the surface of the sea floor. This will help us navigate the ROV at this key site during this cruise — and in future explorations. Together, we hope the data from the Lophelia II expedition will lay the foundation for some fantastic research to come over the next four years.
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