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    Salinity affects wound healing in wild common bottlenose dolphins (Tursiops truncatus)
    (2022-06-13) Orbach, Dara; Hurst, Brianna
    Dolphins are often individually identified by unique naturally-acquired markings. Identification becomes difficult when markings heal, or new scars appear. As salt accelerates wound healing in many organisms, the diminishment of scars on common bottlenose dolphins (Tursiops truncatus) residing in varying natural salinities was determined. South Texas contains the only hypersaline lagoon in the USA, located adjacent to hyposaline waters, with genetically distinct populations of dolphins in the two environments. Photographs of dolphin dorsal fins were collected, and scar stability over time was determined and compared by measuring changes in the relative lengths and surfaces of scars. All scars on dolphins in the hypersaline lagoon completely diminished between three to six years, while scars on dolphins in the hyposaline bay ranged in the amount of fading between three to six years. Data from this case study indicate that high salinity may increase the healing speed of wounds on common bottlenose dolphins compared to low salinity, although a larger sample size is needed for robust statistical comparison. Scar diminishment is an important consideration in determining the temporal reliability of photo identification.
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    Carbon-sulfur signals of methane versus crude oil diagenetic decomposition and U-Th age relationships for authigenic carbonates from asphalt seeps, southern Gulf of Mexico
    (Chemical Geology, 2021-06-11) Abdullajintakam, Sajjad A.; Coffin, Richard B.; Akam, Sajjad A.; Lyons, Timothy W.; McGee, David; Naehr, Thomas H.; Bates, Steven M.; Clarkson, Clay; Reese, Brandi Kiel
    Offshore hydrocarbon accumulations in the Gulf of Mexico (GoM) are often accompanied by natural seepage of oil and gas from subsurface reservoirs into shallow sediments and the water column. This study investigated the temporal patterns and carbon-sulfur (C-S) coupling associated with authigenic carbonate samples recovered from surface sediments of a crude oil seepage site in southern GoM (Chapopote asphalt volcano, Bay of Campeche) using radioactive U-Th dates, and stable C, O, and S isotopes. The results were compared with data from multiple seep sites in the northern GoM where methane seepage is dominant along with non-methane hydrocarbons (ethane, propane, crude oil, etc.). U-Th age-dating of Chapopote seep carbonate samples yielded ages of 13.5 ka to 4.6 ka before present (BP), suggesting that Chapopote asphalt seepage has been ongoing for thousands of years. The results are also consistent with previous studies from the northern GoM that hypothesize that seeps along the GoM continental slope were active during the last deglaciation. δ13CCaCO3 and δ18OCaCO3 values from authigenic carbonates at Chapopote indicated a mixed contribution of methane and non-methane hydrocarbons to the dissolved inorganic carbon (DIC) pool, consistent with previous results. Comparison of δ13CCaCO3 vs. δ34SCRS (CRS = chromium reducible sulfur) from carbonate samples showed noticeable differences at the Chapopote seep site (average δ13CCaCO3 -25‰ VDPB, δ34SCRS -27‰ VCDT) relative to the methane seep-dominated samples from the northern GoM (average δ13CCaCO3 < -40‰ VDPB, δ34SCRS >0‰ VCDT). Our results point toward distinguishable differences in the paired δ13CDIC and δ34Ssulfide signatures produced via the diagenetic processes of sulfate-driven anaerobic oxidation of methane versus non-methane hydrocarbons. These results potentially provide an important proxy for identification of such diagenetic processes within the sedimentary records.
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    A Field Guide to Ward Island
    (1995) Hickman, Graham C.