Variability of Cold-Water Coral Mounds in a High Sediment Input and Tidal Current Regime, Straits of Florida

Authors

Thiago B.S. Correa, University of Miami
Mark Grasmueck, University of Miami
Gregor P. Eberli, University of Miami
John K. Reed, Florida Atlantic University
Klaas Verwer, University of Miami
Samuel J. Purkis, Nova Southeastern UniversityFollow

ResearcherID

B-8552-2013

Document Type

Article

Publication Title

Sedimentology

ISSN

0037-0746

Publication Date

6-2012

Keywords

Autonomous underwater vehicle (AUV), Cold-water coral, Great Bahama Bank slope, Morphometrics, Mound, Straits of Florida

Abstract

Cold-water coral mound morphology and development are thought to be controlled primarily by current regime. This study, however, reveals a general lack of correlation between prevailing bottom current direction and mound morphology (i.e. footprint shape and orientation), as well as current strength and mound size (i.e. footprint area and height). These findings are based on quantitative analyses of a high-resolution geophysical dataset collected with an Autonomous Underwater Vehicle from three cold-water coral mound sites at the toe of slope of Great Bahama Bank. The three sites (80 km² total) have an average of 14 mounds km⁻², indicating that the Great Bahama Bank slope is a major coral mound region. At all three sites living coral colonies are observed on the surface of the mounds, documenting active mound growth. Morphometric analysis shows that mounds at these sites vary significantly in height (1 to 83 m), area (81 to 6 00 000 m²), shape (mound aspect ratio 0·1 to 1) and orientation (mound longest axis 0 to 180°). The Autonomous Underwater Vehicle measured bottom current data depict a north–south flowing current that reverses approximately every six hours. The tidal nature of this current and its intermittent deviations during reversals are interpreted to contribute to the observed mound complexity. An additional factor contributing to the variability in mound morphometrics is the sediment deposition rate that varies among and within sites. At most locations sedimentation rate lags slightly behind mound growth rate, causing mounds to develop into large structures. Where sedimentation rates are higher than mound growth rates, sediment partially or completely buries mounds. The spatial distribution and alignment of mounds can also be related to gravity mass deposits, as indicated by geomorphological features (for example, slope failure and linear topographic highs) in the three-dimensional bathymetry. In summary, variability in sedimentation rates, current regime and underlying topography produce extraordinarily high variability in the distribution, development and morphology of coral mounds on the Great Bahama Bank slope.

DOI

10.1111/j.1365-3091.2011.01306.x

Volume

59

Issue

4

First Page

1278

Last Page

1304

Comments

©2011 The Authors. Journal compilation © 2011 International Association of Sedimentologists

Additional Comments

HBOI project #s: S2156, S2168; American Chemical Society Petroleum Research Fund grant #: 49017ND8

NSUWorks Citation

Thiago B.S. Correa, Mark Grasmueck, Gregor P. Eberli, John K. Reed, Klaas Verwer, and Samuel J. Purkis. 2012. Variability of Cold-Water Coral Mounds in a High Sediment Input and Tidal Current Regime, Straits of Florida .Sedimentology , (4) : 1278 -1304. https://nsuworks.nova.edu/occ_facarticles/253.