Carotenoids indicate differences in diet of the hydrothermal vent crabBythograea thermydron (Brachyura)

Abstract

Carotenoid pigments were used as markers to investigate the sources of energy to two deep-sea hydrothermal vent communities. Specimens of the hydrothermal-vent brachyuran crab Bythograea thermydron were collected at 2 500 m depth from the Rose Garden vent site in the Gal/tpagos Rift Valley in February, November and December 1979, and 2 600 m depth on the East Pacific Rise at 21°N in May 1982. Four carotenoids (astaxanthin, canthaxanthin, echinenone and beta-carotene) have been identified as the pigments responsible for the red color of the eggs of the crabs from the Galfipagos Rift site. Consistent with the fact that animals are unable to synthesize carotenoids de novo, precursors were not present in the crabs' tissues, affirming that these pigments are of dietary origin. The number of ovigerous female crabs and the concentrations of carotenoids in the eggs suggest a readily available source of these pigments in the Galfipagos vent environment. In contrast, the developing eggs of B. thermydron from the 21°N vent site were cream-colored, with only trace quantites of carotenoids and fewer types of carotenoids. Analysis of carotenoid distribution in both females and males in these two populations indicates a very low level of carotenoids in the diet of the 21 °N vent crabs, and reflects differences in trophic interactions and primary production at the two vent sites. The few types and low concentration of carotenoids in B. thermydron indicate a diet that is different from non-vent, deep-sea crustaceans. We hypothesize that the source of carotenoids are bacteria within the vent community, and not ultimately from photosynthetic production. cD zz~ o c O © 0 c © O © (D

Decapod crustaceans from hydrothermal vents and cold seeps: a review through 2005

“…–Galapagos Rift, Rose Garden vent site; 2500 m; February, November and December 1979; 215 crabs collected from traps (DeBevoise, Childress & Withers, 1990).…”

“…–EPR, collapse pit site; 20°50′N, 109°00′W; 2600 m; May 1982; from traps; 19 specimens (DeBevoise et al. , 1990).…”

“…, 2002), hyperglycemic hormones (Toullec et al. , 2002), haemocyanin activity and oxygen affinity (Arp & Childress, 1981; Sanders, Art & Childress, 1988; Sanders & Childress, 1992), dietary carotenoids (DeBevoise et al. , 1990), predation on other vent organisms (Voight, 2000, citing Jollivet 1993 (see also Micheli et al.…”

“…Bythograeid crabs respond well to baited traps, and as a result some species are known from relatively large numbers of specimens [e.g. the more than 80 specimens forming the basis of Hessler & Martin's (1989) description of Austinograea williamsi , and the more than 200 specimens of Bythograea thermydron noted by DeBevoise et al . (1990)].…”

Photosynthetic Pigments Contained in Surface Sediments from the Hydrothermal System of Guaymas Basin, Gulf of California

“…According to Nègre-Sadargues et al [38], carotenoid pigments are obtained from bacteria, fungi, or plants. DeBevoise et al [39] suggested that the carotenoids found in the crab eggs of Bythograea thermydron are produced in situ by chemoautotrophic bacteria present and are not derived from phytodetritus as one may expect.…”