Cooperative Investigations of Deep-Sea Brine Areas in the Red Sea


DOEI Funded Project: 2008


The central rift zone of the Red Sea is known to contain more than 20 metalliferous morphological depressions filled by highly saline hot brines and hydrothermal activity.  Individual sites, like Shaban, Kebrit, Atlantis II, and Discovery Deep have been variously examined for their noble gases and hydrocarbon gases, hydrography, and isotopic signatures.  In contrast to most hydrothermal areas, the chemistry of fluids in the Red Sea brine pools results not only from reactions of seawater with basalts, but also from interactions with another geochemical reservoir, the Miocene evaporates underlying the entire Red Sea. With few exceptions, hydrothermal systems around the global mid-ocean ridge system provide reduced chemicals with which to sustain great abundances of highly specialized organisms with novel ecologies. Locating chemosynthetic communities in the Red Sea is the essential first step to discovering new species, novel ecological niches, and the answering the long-standing question of how vent fauna have evolved along the global mid-ocean ridge system.

Similarly, the geologic context of active brine pools and relict hydrothermal vent sites is critical for evaluating the controls on fluid circulation including the spatial scales of fluid pathways and heat sources. We will use imagery collected by TowCam along transects coupled with high-resolution seafloor bathymetric profiles to evaluate the extent of recent magmatic activity manifest at the seafloor and the distribution of faulting and fissuring in the areas surrounding the brine pools. Near-bottom observations will be merged with regional remotely sensed data sets (e.g., bathymetry, sidescan sonar) in order to characterize the relevant geologic characteristics over larger spatial scales.  We will correlate the local and regional species diversity and the biological community structure, with the diverse tectonic settings and historical activity (as deduced by the near-bottom magnetics) through the analysis of near-bottom TowCam imaging and magnetic surveys. We will conduct preliminary analyses of biological, geological and geophysical data resulting from towed deep-sea digital camera (TowCam) surveys to be conducted in and across brine pool rifts in the Red Sea as part of the joint KAUST/WHOI collaborative cruises in Fall 2008. TowCam data will be acquired during Leg 2 (A. Bower, Chief Sci.) which has largely been funded by KAUST as an add-on to the overall project.  Analysis of these data have important and broad implications for better understanding linkages between global hydrothermal vent communities and the specific nature of hydrothermal venting in brine pool settings within a nascent mid-ocean ridge forming in a young continental rift.  Characterization of seafloor geology, in concert with the biological mapping and magnetics data will help us to better understand the nature of hydrothermal processes in these unique settings and permit correlation between distinct Red Sea sites and comparison to well-studied mid-ocean ridge vent sites.