Chemosynthetic Mussels at a Brine-Filled Pockmark in the Northern Gulf of Mexico

MacDonald, Ian R.; Reilly, James F.; Guinasso, Norman L.; Brooks, James M.; Carney, Robert S.; Bryant, William A; Bright, Thomas J.

doi:10.1126/science.248.4959.1096

Cited by 170 publications

(96 citation statements)

References 20 publications

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“…The methane and other reduced carbon compounds in the shallow sediments at this site largely derive from seepage from deeper source rocks (MacDonald et al 1990, Sassen et al 1999. The H 2 S is apparently largely produced by anaerobic sulfate-reducing bacteria in the shallow sediments and is linked to methane oxidation and possibly the oxidation of higher molecular weight hydrocarbons (Formolo et al 2004, Joye et al 2004), but some sulfides may also be associated with the oil reservoir seepage (MacDonald et al 1989).…”

Section: Abstract: Hydrocarbon Seeps · Chemosynthesis · Sulfur Isotopesmentioning

confidence: 99%

Nutritional associations among fauna at hydrocarbon seep communities in the Gulf of Mexico

MacAvoy¹,

Fisher²,

Carney³

et al. 2005

Mar. Ecol. Prog. Ser.

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Section: Abstract: Hydrocarbon Seeps · Chemosynthesis · Sulfur Isotopesmentioning

confidence: 99%

Nutritional associations among fauna at hydrocarbon seep communities in the Gulf of Mexico

MacAvoy¹,

Fisher²,

Carney³

et al. 2005

Mar. Ecol. Prog. Ser.

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“…Joye et al: Geophysical and geochemical signatures of Gulf of Mexico seafloor brines steep concentration gradients of dissolved oxygen and redox metabolites as well as temperature and salinity (Anschutz et al, 1998;Van Cappellen et al, 1998). Smaller brinefilled features form following rapid fluid expulsion, dissolution of shallow salt bodies, and/or the coalescence of salt diapirs which generate surface depressions that gradually fill with brine through lateral density flows Bryant et al, 1991;MacDonald et al, 1990;Roberts and Carney, 1997). These brine pools form a stable interface with seawater at the level of the crater rim (MacDonald et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…Brine-filled basins with diameters of several kilometers and depths of hundreds of meters are known from the Mediterranean Sea (Cita, 1990;Cita et al, 1989;De Lange and Brumsack, 1998;MEDINAUT/MEDINETH, 2000) and the outer continental slope of the Gulf of Mexico (Sheu, 1990;Bouma and Bryant, 1994;MacDonald et al, 1990;Neurauter and Bryant, 1990;Neurauter and Roberts, 1994;Shokes et al, 1977). Geochemical profiles through the seawater-brine interface in these basins show 296 S. B.…”

Section: Introductionmentioning

confidence: 99%

“…Smaller brinefilled features form following rapid fluid expulsion, dissolution of shallow salt bodies, and/or the coalescence of salt diapirs which generate surface depressions that gradually fill with brine through lateral density flows Bryant et al, 1991;MacDonald et al, 1990;Roberts and Carney, 1997). These brine pools form a stable interface with seawater at the level of the crater rim (MacDonald et al, 1990). Sulfide-rich brines also occur as aquatanes at the base of deep-sea escarpments, for example on the western margin of the Florida platform (Commeau et al, 1987), where they are associated with abundant biomass of chemoautotrophic fauna.…”

Section: Introductionmentioning

confidence: 99%

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Geophysical and geochemical signatures of Gulf of Mexico seafloor brines

et al. 2005

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Abstract. Geophysical, temperature, and discrete depthstratified geochemical data illustrate differences between an actively venting mud volcano and a relatively quiescent brine pool in the Gulf of Mexico along the continental slope. Geophysical data, including laser-line scan mosaics and subbottom profiles, document the dynamic nature of both environments. Temperature profiles, obtained by lowering a CTD into the brine fluid, show that the venting brine was at least 10 • C warmer than the bottom water. At the brine pool, thermal stratification was observed and only small differences in stratification were documented between three sampling times (1991, 1997 and 1998). In contrast, at the mud volcano, substantial temperature variability was observed, with the core brine temperature being slightly higher than bottom water (by 2 • C) in 1997 but substantially higher than bottom water (by 19 • C) in 1998. Detailed geochemical samples were obtained in 2002 using a device called the "brine trapper" and concentrations of dissolved gases, major ions and nutrients were determined. Both brines contained about four times as much salt as seawater and steep concentration gradients of dissolved ions and nutrients versus brine depth were apparent. Differences in the concentrations of calcium, magnesium and potassium between the two brine fluids suggest that the fluids are derived from different sources, have different dilution/mixing histories, or that brine-sediment reactions are more important at the mud volcano. Substantial concentrations of methane, ammonium, and silicate were observed in both brines, suggesting that fluids expelled from deep ocean brines are important sources of these constituents to the surrounding environment.

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“…hydrogen sulphide and hydrocarbons like methane (Cavanaugh et al, 2006;Dando, 2001;Duperron, 2010). In turn, such communities could be exploited by specialized metazoans through complex symbiotic relationships (see MacDonald et al, 1990;Olu-Le Roy et al, 2007;Taviani, 2001;Duperron, 2010, with references). Pockmarks are also sites were methane-related authigenic carbonates could be generated Hovland and Judd, 1988;Gontharet et al, 2007).…”

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confidence: 99%

The Gela Basin pockmark field in the strait of Sicily (Mediterranean Sea): chemosymbiotic faunal and carbonate signatures of postglacial to modern cold seepage

et al. 2013

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The geo-biological exploration of a pockmark field located at ca. 800 m below sea level in the Gela basin (Strait of Sicily, Central Mediterranean) provided a relatively diverse chemosymbiotic community and methane-imprinted carbonates. To date, this is the first occurrence of such a type of specialised deep-water cold-seep communities recorded from this key region, before documented in the Mediterranean as rather disjunct findings in its eastern and westernmost basins. The thiotrophic chemosymbiotic organisms recovered from this area include empty tubes of the vestimentiferan Lamellibrachia sp., loose and articulated shells of lucinids (Lucinoma kazani, Myrtea amorpha), vesicomyids (Isorropodon perplexum), and gastropods (Taranis moerchii). A callianassid decapod (Calliax sp.) was consistently found alive in large numbers in the pockmark mud. Their post-mortem calcified parts mixed with molluscs and subordinately miliolid foraminifers form a distinct type of skeletal assemblage. Carbonate concretions display δ¹³C values as low as −40‰ PDB suggesting the occurrence of light hydrocarbons in the seeping fluids. Since none of the truly chemosymbiotic organisms was found alive, although their skeletal parts appear at times very fresh, some specimens have been AMS-¹⁴C dated to shed light on the historical evolution of this site. Lamellibrachiav and Lucinoma are two of the most significant chemosymbiotic taxa reported from various Mediterranean cold seep sites (Alboran Sea and Eastern basin). Specimens from station MEDCOR78 (pockmark #1, Lat. 36°46´10.18" N, Long. 14°01´31.59" E, 815 m below sea level) provided ages of 11736 ± 636 yr cal BP (Lamellibrachia sp.), and 9609.5 ± 153.5 yr cal BP (L. kazani). One shell of M. amorpha in core MEDCOR81 (pockmark #6, Lat 36°45´38.89" N, Long 14°00´07.58" E, 822 m below sea level) provided a sub-modern age of 484 ± 54 yr cal BP. These ages document that fluid seepage at this pockmark site has been episodically sustaining thiotrophic macrobenthic communities since the end of the Younger Dryas stadial up to sub-recent times

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Chemosynthetic Mussels at a Brine-Filled Pockmark in the Northern Gulf of Mexico

Abstract: A large (540 square meters) bed of Bathymodiolus n. sp. (Mytilidae: Bivalvia) rings a pool of hypersaline (121.35 practical salinity units) brine at a water depth of 650 meters on the continental slope south of Louisiana. The anoxic brine (dissolved oxygen Show more

Cited by 170 publications

References 20 publications

Nutritional associations among fauna at hydrocarbon seep communities in the Gulf of Mexico

Nutritional associations among fauna at hydrocarbon seep communities in the Gulf of Mexico

Geophysical and geochemical signatures of Gulf of Mexico seafloor brines

The Gela Basin pockmark field in the strait of Sicily (Mediterranean Sea): chemosymbiotic faunal and carbonate signatures of postglacial to modern cold seepage

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