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Click below to go to the Cruise Logs - (photo credit: Lophelia Coral - Open-File Report 2008-1148 & OCS Study MMS 2008-015)


Cruise Log: 9/19/2009    

Connectivity of Habitat Forming Deepwater Corals

Andrea M. Quattrini

Andrea Quattrini aboard the Johnson-Sea-Link - click to enlarge
Andrea Quattrini aboard the Johnson-Sea-Link - click to enlarge
I am a first year PhD student in the biology department at Temple University and am extremely excited to be onboard the Seward Johnson participating in the Lophelia II project. I have sailed with members of this research team for the past 7 years, but this is the first field season that I will be collecting data for my own research projects. My graduate research focuses on the "other" corals. Octocorals are diverse, abundant and create reef habitat in the deep-sea. In the Gulf of Mexico, one group of octocorals, the gorgonians, occurs to 3000 m creating both horizontal and vertical structure for animals to inhabit. Numerous organisms often live directly on, in between, or around the coral colonies.

Callogorgia spp.
Callogorgia spp. are important habitat forming gorgonians in the Gulf of Mexico. Individuals of this genus form extensive monotypic fields, where numerous colonies essentially cover the bottom in particular areas. These corals also serve as a nursery habitat for egg-laying sharks and may have a symbiotic relationship with certain brittle stars, which are often found living directly on the coral colonies.

Callogorgia sp - click to enlarge
Callogorgia sp - click to enlarge
Three Callogorgia taxa (C. americana americana, C. americana delta, C. gracilis) are currently known to occur in the Gulf of Mexico, and one, C. americana delta, appears to be endemic. With any ecological or biological study it is imperative to know what species you are working with and where they occur. Therefore, my first research questions include: What species occur in the Gulf, are they genetically different, and how are they distributed? My first task will be to identify Callogorgia spp specimens collected on expeditions this year using both morphological and genetic methods. Identification of Callogorgia to species level is largely based on sclerites, "scale-like" structures that provide strength to the axes of gorgonian colonies. The number, arrangement and shape of sclerites are critical morphological characters used to identify gorgonians. However, Callogorgia species identification is not straightforward, and the use of molecular techniques coupled with the morphology will facilitate accurate identifications of species.

Connectivity: The Central Theme
After determining what species of Callogorgia occur in the Gulf and how they are genetically related, the next step is to examine their population structure. I will investigate how Callogorgia are spatially connected throughout the Gulf of Mexico using molecular techniques. This will allow insight into gene flow and direction, genetic diversity, and the degree of population isolation. Determining the pathways and degree of genetic exchange (see daily log by Cheryl Morrison) is important to effectively conserve deepwater coral habitat. In addition, protecting the "source" of this exchange is important if species are to survive from harmful human or environmental disturbances. I am hopeful that my dissertation research can aid managers in making effective decisions in order to protect these precious ecosystems.

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