Project Summary for 2006-14A: Deep coral habitat mapping along the southeastern US continental slope using an autonomous underwater vehicle with multibeam sonar.
Detailed knowledge about aquatic habitats in waters <200 m is accumulating rapidly. However, information concerning deep sea habitats (with a few isolated exceptions such as hydrothermal vents) is either lacking or is very general. One of the main reasons for this discrepancy has been a lack of affordable and/or readily available technology that could be applied to deeper waters. That situation is changing, and this project will capitalize on the availability of ships using multibeam sonar technology and an Autonomous Underwater Vehicle (AUV) to collect detailed structural data on important deep water habitats of the southeastern US. Multibeam mapping via ships will provide one level of bottom detail and an AUV using multibeam is an effective vehicle for the detailed mapping that is proposed to be conducted over rugged continental slope habitats.
While making significant contributions, past research missions have only begun to document the extensive reef-like habitat and biota along the slope from Cape Lookout, NC through the Florida Straits (350-900 m). Although successful, past cruises were guided by very general coal habitat locations and low resolution bathymetry. Many past stations were better known reef sites that required (by necessity) little search time to locate. The cruises proposed here will generate needed structural details on previously sampled sites and allow time to explore for new coral banks.
Studies have suffered from a lack of detailed maps of the southeastern US continental slope. This has cost the research community huge amounts of expensive ship time searching for coral habitats and trying to describe their structures. We have been forced to rely on inaccurate single beam depth soundings to guide our submersible and other sampling. Such bathymetric data are not of survey quality and result in a distorted and misleading view of bottom topography. A great improvement to the mapping effort would be provided by the use of NOAA multibeam-capable ships and the NURC/NIUST AUV supporting detailed multibeam swath bathymetric mapping. Such high resolution mapping tools provide great advantages over the normally available single beam depth sounders. The multibeam data, along with past exploratory data, will guide other ongoing sampling to address a variety of deep coral issues/observations. Ample justification for this multibeam mapping task exists.
This project has similar goals for both years of field work. Because of the large area that needs to be mapped, we request at least 8 days of multibeam ship time in the first year (2006 field season) and at least 10-12 days of AUV and support vessel time in the second year (2007 field season). In the first year coral banks (350-900 m) and surrounding areas off of North Carolina (three major areas) and South Carolina (two major areas) will be mapped. Depending on weather, mapping speeds, and other logistics more areas might be mapped in the first year, possibly extending into coral habitats off Georgia and Florida (450-800 m). First year data will provide the background to guide second year AUV efforts. Use of the AUV in the second year will provide more bottom details than the data collected in the first year. Since the AUV maps at a slower speed than first year systems, but collects higher resolution data, we may not cover the complete area in the second year. First year results will allow selection of target areas for AUV mapping in the second year, emphasizing those with existing ground truth data (e.g., submersible dives). The multibeam data (bathymetry and backscatter) will be matched with existing video and visual ground truth data from previous submersible dives in the study areas. This will facilitate habitat interpretations for the multibeam data. We also have target locations in the Gulf of Mexico that may be mapped if project priorities or logistics dictate work in that region
Science Objectives
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