The isolation, identification, and characterization of bacteria associated with the deep-sea coral Lophelia pertusa

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
S. Gold (Creator)
Institution
Western Carolina University (WCU )
Web Site: http://library.wcu.edu/
Advisor
Seán O'Connell

Abstract: Cold-water corals (CWC) form the structural basis of highly diverse and productive ecosystems in the deep, dark ocean, serving as important spawning, nursery, and breeding habitat for many fishes and invertebrates. As such, they play an important role in supporting fisheries that humans rely on, as well as general ocean health, which is of critical importance to Earth as the effects of climate change unfold. CWCs are heterotrophic filter feeders, and their ability to survive in dark, oligotrophic waters may be linked to partnerships with microbial symbionts that participate in nutrient cycling and conservation. While indirect methods–DNA sequencing, whole genome analysis, isotopic analysis–have been used to hypothesize the roles of these symbionts, few studies have grown cultures of associated microbes and directly observed the metabolic processes involved in carbon and nitrogen turnover. In this study, bacteria cultured from the globally distributed, deep-sea coral Lophelia pertusa were isolated and characterized according to morphological and physiological characteristics. Sanger sequencing of 16S rRNA from the isolates yielded a diversity of bacterial species in the phylum Proteobacteria. In culture, isolates demonstrate the ability to use a variety of organics as carbon, nitrogen, and energy sources, the most notable of which is chitin, a polymer containing both carbon and nitrogen that is abundant in marine systems. Additionally, preliminary evidence suggests the ability of one isolate to fix nitrogen. These findings corroborate evidence of nutrient cycling in CWCs and support the hypothesis that microbial associates of these corals are an important aspect of their ecophysiology and likely help fuel their productivity. Physical and physiological stress induced by changes in the environment resulting from human activities and climate change couldinfluence host-microbe interactions, altering the ability of CWCs to conserve and recycle limiting resources. Loss of CWC ecosystems would mean loss of critical habitat and a globally relevant carbon sink.

Additional Information

Publication
Thesis
Language: English
Date: 2020
Keywords
coral, marine, microbial ecology, microbiology, nutrient cycling
Subjects
Deep sea corals -- Ecology -- Atlantic Ocean
Deep sea corals -- Ecology -- South Carolina -- Charleston
Marine microbial ecology
Lophelia pertusa
Nutrient cycles
Deep sea corals -- Health aspects
Host-bacteria relationships

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