2010 NSF RAPID cruise:macrocrustaceans and associated fauna offshore the NW Gulf of Mexico

The NSF RAPID grant (DEB-1045690) awarded to Suzanne Fredericq and Darryl Felder from the University of Louisiana at Lafayette (http://biology.ucs.louisiana.edu/) and entitled "RAPID: Impacts of the Deepwater Horizon crude oil spill on the diversity of macroalgae and macrocrustaceans inhabiting deepwater hard banks in the NW, NE and SE Gulf of Mexico" is facilitating critical assessment of pre- and post-oil spill impacts on the diversity, vitality, and distribution of these offshore organisms. Results analyzed from the first 5-day leg of the dredging expedition off Louisiana, Mississippi and Alabama (December 2-6, 2010) indicate that the diversity of macrocrustaceans appeared limited. Shown in this video are deployments of a benthic skimmer and examples of macrocrustaceans and associated fauna (sponges, sea cucumbers, molluscs, nemertine worms, fish) dredged from ~250-1750 m depth. A separate video highlighting Bryozoa collected with the benthic skimmer during this RAPID cruise can be viewed at http://www.youtube.com/nemastoma2#p/u/2/8Mnh07sKWkk.

The molluscs filmed here were preserved and identified by Emilio Garcia: Cryptopecten phrygium, Pleurotomella pandionis, Leucosyrinx verrillii, Gymnobela agassizii, and Propeamussium sp.

A benthic skimmer provided an ancillary tool for work on lower slopes of hard banks and surrounding bottom, taking advantage of ship access to these locations in the northern Gulf of Mexico, and allowing a comparison to established data sets for especially deep benthos. While operated below depths inhabited by most macroalgae, it provided excellent intact samples of benthic macrocrustaceans and associated fauna. The skimmer is constructed precisely in accord with those used in the most extensive previous surveys of such Gulf environs by the R/V Alaminos in the 1960's through early 1970's (Pequegnat et al. 1970). This standardization of tools potentially allows comparisons of new collections to a substantial published record of deep Gulf benthos in proximity to the oil spill. Reference: Pequegnat, W. E., T.J. Bright & G.M. James. 1970. The benthic skimmer, a new biological sampler for deep-sea studies. TAMU Oceanographic Studies 1: 17-20.

Seaweeds and maacrocrustaceans collected with a Hourglass-design box dredge from depths of 53-90 m can be viewed at http://www.youtube.com/nemastoma2#p/u/0/2CY_ZaNwsxA.

In an accompanying video (see http://www.youtube.com/nemastoma2#p/u/4/WLOXjFbw85s ) strong petroleum odors were pervasive when the dredge was retrieved from ~55 m depth at Ewing Bank 2 (Fish Haven) far west of the Deepwater Horizon Explosion; samples included individual carbonate nodules covered by light crude oil.

The expedition departed from LUMCON in Cocodrie LA, on board the R/V Pelican, a 32 m (105ft) ABS Class "A-1+ Oceanographic, steel-hull coastal research vessel operated by UNOLS.

Filmed and edited by S. Fredericq.

Category:

Science & Technology

Tags:

• benthos
• benthic
• macrocrustaceans
• sea cucumber
• Holuthurians
• molluscs
• benthic skimmer
• Mississippi
• Alabama
• Louisiana
• National Science Foundation
• biodiversity
• systematics
• ecosystem
• seaweeds