HCNSO Student Theses and Dissertations

Defense Date

8-10-2018

Document Type

Thesis

Degree Name

M.S. Marine Biology

Second Degree Name

M.S. Coastal Zone Management

First Advisor

Charles G. Messing

Second Advisor

Brian K. Walker

Third Advisor

Bernhard Riegl

Abstract

Quantitative photographs of benthic communities at two northern Miami Terrace sites, originally investigated as part of an environmental impact survey in advance of the proposed Calypso pipeline, and two Pourtalès Terrace sites, investigated as part of an exploration of deep-sea coral and sponge ecosystems (DSCEs) within the Pourtalès Terrace Deep-water Coral Habitat Area of Particular Concern (CHAPC), were reanalyzed and compared for similarities and differences. Both terraces are part of an elongated lithified platform that parallels the southeastern Florida coast at depths averaging between 250 and 450 m. Although both sites have similar geological origins and lie under the Florida Current, previous work has suggested that the two terraces support different benthic faunas.

Images from 28 phototransects from the two terraces were condensed into two depth bins of 250-300 m and 450-550 m. Distributions of taxa compared among individual sites were depth driven, whereas distributions of taxa between the northern Miami Terrace and Pourtalès Terrace appeared to be driven by geological features, as sites at similar depths had different communities and densities, with the only distinguishing variables being location and geologic features. Results indicate that location is the driving factor contributing to differences in deep-water benthic communities between the two terraces. Depth bin 450-550 m was dominated on the Miami Terrace by hard substrates supporting octocorals (Pseudodrifa nigra, Primnoidae, Keratoisis sp., and Anthomastus sp.), anemones, and sponges (mainly Phakellia sp.) and on the Pourtalès Terrace by hard substrates and coral rubble supporting Paramuricea unid sp. 3, Comatonia cristata, Plumarella sp. 2, and Astrophorina unid. sp. 4. Depth bin 250-300 m on the northern Miami Terrace was dominated by sediment substrates and supported anemones, soft corals and zoanthids, and on the Pourtalès by sediment-veneered hard bottom with Stylaster miniatus, Plumarella unid sp., Hydroida unid sp., and Isididae unid sp. 2.

The relationships between depth, location and geomorphology may be useful in designing future benthic mapping projects. In addition, species densities and protection statuses can aid future community assessments between protected habitats and non-protected habitats to measure the effectiveness and management strategies of deep-water marine protected areas. The relationships revealed by this study can be used to support the management of the Miami Terrace, Pourtalès Terrace, and other sites to conserve deep-water coral environments.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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