Sunday, June 22, 2014

Research Cruise: Hunting undiscovered hard bottom habitats

RV Weatherbird II – June 19-29, 2014
Geomorphology and Habitat, Outer Continental Shelf

Welcome to the at-sea blog from the RV Weatherbird II in the northeast Gulf of Mexico. We are conducting seafloor mapping along the outer shelf about 70 km seaward of Panama City, FL. 

Geomorphology and habitat classification is one of several major tasks identified by the Deep-C Consortium for focused research. Specifically, “To characterize sea floor geomorphology, bathymetry, sediment, and primary benthic habitats specific to the defined region with an emphasis on topographical features that influence deep sea to shelf connectivity.” 

We are hunting for undiscovered hard bottom habitat on this cruise using sonar to map the sea floor. Our data products will be sidescan backscatter maps indicating bottom types (sediments, hard bottom, structural features) and high-resolution swath bathymetry (seafloor morphology). Our target area is the outer continental shelf in 50 to 100 meters water depth where essential fish habitat and potential mesophotic coral ecosystems associate with high-relief rocky outcrops. The hard-bottom habitat can support very diverse benthic communities of organisms that attach to hard surfaces (such as corals) and support pelagic communities (such as grouper). The distribution patterns and extent of these bottom types are poorly mapped. 

Map showing our general area of operations.(Source: Stan Locker, USF)
We operate around the clock, stopping a couple of times each day to do a CTD (conductivity, temperature, depth) cast to measure sound-velocity profiles of the water column, and to collect water samples. The sound velocity is needed for the bathymetry data processing, and water sampling is an add-on we can do at the same time for Deep-C researchers studying plankton. More on that later...

We are using a Teledyne-Benthos C3D interferometric sidescan sonar that produces high-quality 200 kHz backscatter imagery and sub-meter resolution swath bathymetry. We are scanning a 500 m wide swath of seafloor below the ship. We are also acquiring acoustic imaging of the water column and seafloor using an EK60 echo sounder on the WBII. The EK60 can be used for fish stock assessment and will be directly correlated with bottom type mapped by the C3D. 

A key feature of this blog will be entries to be made by the student volunteers, they are standing watch around the clock, monitoring data acquisition, minding navigation, and learning to process the sonar data to make maps in real time. Something to look forward to.

Time to finish up this entry. I wanted to share this photo taken yesterday morning. 

A front moving in kicked off some amazing waterspouts about 4 miles away.
Morning of June 21, 2014, near Madison Swanson Marine Reserve.
(Photo credit: Stan Locker, USF)

Weather has actually been great so far, minimal seas. 

Post Author:
Dr. Stan Locker

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