Explorations | Life on the Edge 2005

Life on the Edge 2005:
Exploring Deep Coral Communities

October 16 - November 4, 2005

Our ongoing studies (2000-present) exploring southeastern US (SEUS) and Gulf of Mexico continental slope coral ecosystems are based on hypotheses that these habitats are ecologically important and productive, yet they are poorly documented. There is increasing evidence that deep water (aphotic) corals are important fish habitat, hold data on ocean climate and productivity, and are hotspots of biodiversity, including new species. Deep coral habitats are more abundant than previously known, and at the same time they are being threatened. The SEUS and Gulf of Mexico may have the most extensive deep coral areas in the US; however, these large regions are poorly explored (even considering recent expeditions). These high profile features may concentrate resources and enhance local productivity in ways similar to seamounts. Also, like seamounts, such unique habitats have escaped detailed examination in the SEUS not only because of their great depths but also because the bottom topography is rugged and the habitats are overlain by extreme currents (i.e., Gulf Stream). Thus, most studies on deep coral banks require expensive unconventional sampling techniques (e.g., manned submersibles). Locating, describing, and mapping deep corals and conducting basic biological studies in these habitats are priorities for our research. Our previous cruises have documented deep coral and outer shelf reef habitats and associated biota, but these missions have only begun to quantify this extensive habitat in the region. Our studies have yielded many new records of biota, new ecological data, new data on habitat distributions/structures, and data on water column trophic connectivity. This cruise continues and expands our explorations of these unique and relatively unknown deep water habitats.

While the SEUS harbors many deep coral species, few create extensive, complex reef structures. Lophelia pertusa, the major mound forming coral in the deep sea, is a cosmopolitan species and is the dominant hard coral deeper than 300 m through the SEUS and Gulf of Mexico. We have concentrated our work around L. pertusa areas (because of its abundance, wide distribution, and structure forming abilities), but our objectives also apply to most hard substrate habitats including mixed corals and sponges.

We will locate and sample poorly studied middle slope coral banks (Lophelia mostly, 360-800 m) from Cape Lookout, NC to southeastern FL (see Mission Plan). During this expedition we will cover over 650 nautical miles (1,205 km). We will use a manned submersible (Johnson-Sea-Link, JSL) to quantify biota and habitat on and near reefs via standardized video observations. The JSL will collect samples of corals and associated invertebrates for various purposes. Each dive will have multiple objectives, with some tasks given priority. We will also sample the whole water column using a variety of ship deployed nets. As an integrated regional exploration of deep coral habitat physical structure and ecology, this interconnected, multidisciplinary approach should advance our understanding of critical habitats. Using standardized methods throughout this large area will allow us to compare complex habitats over depth and geographic regions.

 

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Updates & Logs
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