TITLE:
Cold Seeps Associated with Structured Benthic Communities: More Accurate Identification and Evaluation Using a New Multibeam Survey Methodology in the Offshore Southern Colombian Caribbean
AUTHORS:
Adrian Digby, Vladimir Puentes, Jorge León
KEYWORDS:
Backscatter, Cold Seeps, Chemosynthetic Communities, Southern Colombian Caribbean
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.5,
May
27,
2016
ABSTRACT: A new methodology was
developed to identify cold seeps and structured benthic communities associated,
which was applied for the first time in the offshore southern Colombian
Caribbean. The integral method consists on a new processing of double-coverage
(200%) high-resolution backscatter data combined with bathymetric information;
validation was done correlating identified gas plumes, seabed cores and drift
camera surveys. Results showed that the elimination of artefacts and the
increased signal of the backscatter data allowed accurate plotting of seep
boundaries and categorization of seeps into an activity catalogue, with more
than 200 seeps identified. Most seeps have chemosynthetic communities
associated and data analysis from a previous survey showed two ridges with hard
ground as the only possible areas for the development the of deep- water
corals. Seep results were compared with designated Areas of Significance for
Biodiversity (ASB) identifying seeps both within and outside the ASBs, and
showing that the presence of seeps and chemosynthetic communities associated
were driven more by geological processes than for big-scale seabed morphology,
since they were found in both plains and ridges. This methodology allows an
accurate seabed map of structured benthic communities, which may work as a
precise geo-hazard map to ensure the oil & gas industry can avoid these
areas of shallow gas for further developments, and as a map of deep-water structured
benthic communities with environmental significance.