Theses and Dissertations - UTB/UTPA
Date of Award
7-2015
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Dr. David Hicks
Second Advisor
Dr. Jude Benavides
Third Advisor
Dr. Carlos Cintra-Buenrostro
Abstract
Community composition and distribution of coral species in the mesophotic zone off the South Texas Coast were cataloged from five relict mid-shelf coral algal banks referred to as the South Texas Banks including, from north to south, Baker, Aransas, Dream, Blackfish Ridge, and a previously undescribed reef thereto referred as Harte Bank. Hermatypic corals flourished at these sites, approximately 21,000 to 12,000 years BP in the late Pleistocene to early Holocene epochs. Today these reefs are located 97 km offshore and protrude to heights ranging 58 to 83 m below the sea surface with portions extending 20 to 30 m beneath the seafloor. Reef coral taxa were quantified from Remotely Operated Vehicle (ROV) video collected during the September 2012 Schmidt Ocean Institute R/V Falkor cruise. Multiple ROV transects were conducted across each of the relic banks generating ~36 h of video footage. Coral taxa densities (individual/m2) were estimated from discrete 30 sec video segments. Bank coral communities varied significantly (F= 4.18, df=4, 222, p=0.001) across banks and topography breaks (slope and terrace). Pairwise testing indicated significant differences among all terrace communities (P0.95) to the geographic and geomorphic features including bank area, rugosity, longitude, and number of site components. This study provides the first quantitative assessment of coral communities residing at the South Texas Banks; an area that was first explored approximately 45 years ago. The unique coral assemblage is an important component to the ecology of these structures offering habitat complexity for reef associated taxa. The ecological importance of these structures as essential marine habitat is clear with having coral species of the South Texas Banks extending throughout the Gulf of Mexico suggesting connectivity within the basin occurs requiring further investigation.
Granting Institution
University of Texas Brownsville
Comments
Copyright 2015 Rebekah E. Rodriguez. All Rights Reserved.