Hypotaurine and thiotaurine as indicators of sulfide exposure in bivalves and vestimentiferans from hydrothermal vents and cold seeps
|Author(s)||Brand G1, Horak R1, 2, Le Bris Nadine3, Goffredi S4, 5, Carney S6, 7, Govenar B6, 8, Yancey P1|
|Affiliation(s)||1 : Whitman Coll, Dept Biol, Walla Walla, WA 99362 USA.
2 : Thomas Jefferson Univ, Philadelphia, PA 19107 USA.
3 : IFREMER, Ctr Brest, Dept Eude Ecosyst Profonds, F-29263 Plouzane, France.
4 : CALTECH, Pasadena, CA 91125 USA.
5 : Monterey Bay Aquarium Res Inst, Moss Landing, CA USA.
6 : Penn State Univ, Dept Biol, University Pk, PA 16802 USA.
7 : Mote Marine Lab, Sarasota, FL 34236 USA.
8 : Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA.
|Source||Marine Ecology (0173-9565) (Blackwell science), 2007-03 , Vol. 28 , N. 1 , P. 208-218|
|WOS© Times Cited||21|
|Keyword(s)||Vestimentiferan, Vesicomyid, Thiotaurine, Taurine, Hypotaurine, Bathymodiolin|
|Abstract||Vesicomyid clams, vestimentiferans, and some bathymodiolin mussels from hydrothermal vents and cold seeps possess thiotrophic endosymbionts, high levels of hypotaurine and, in tissues with symbionts, thiotaurine. The latter, a product of hypotaurine and sulfide, may store and/or transport sulfide non-toxically, and the ratio to hypotaurine plus thiotauririe (Th/[H + Th]) may reflect an animal's sulfide exposure. To test this, we analyzed seep and vent animals with in situ sulfide measurements. Calyptogena kilmeri clams occur at high-sulfide seeps in Monterey Canyon, while C. (Vesicomya) pacifica clams occur at seeps with lower levels but take up and metabolize sulfide more effectively. From one seep where they co-occur, both had gill thiotaurine contents at 22-25 mmol kg(-1) wet mass, and while C. (V.) pacifica had a higher blood sulfide level, it had a lower Th/[H + Th] (0.39) than C. kilmeri (0.63). However, these same species from different seeps with lower sulfide exposures had lower ratios. Bathymodiolus thermophilus [East Pacific Rise (EPR 9 degrees 50' N)] from high-(84 mu M) and a low-(7 mu M) sulfide vents had gill ratios of 0.40 and 0.12, respectively. Trophosomes of Riftia pachyptila (EPR 9 degrees 50' N) from medium-(33 mu M) and low-(4 mu M) sulfide vents had ratios of 0.23 and 0.20, respectively (not significantly different). Ridgeia piscesae vestimentiferans (Juan de Fuca Ridge) have very different phenotypes at high- and low-sulfide sites, and their trophosomes had the greatest differences: 0.81 and 0.04 ratios from high- and low-sulfide sites, respectively. Thus Th/ [H + Th] may indicate sulfide exposure levels within species, but not in interspecies comparisons, possibly due to phylogenetic and metabolic differences. Total H + Th was constant within each species (except in R. piscesae); the sum may indicate the maximum potential sulfide load that a species faces.|