Trophic structure of hydrothermal vent communities at Myojin Knoll and Nikko Seamount in the northwestern Pacific: Implications for photosynthesis-derived food supply

Abstract

Abstract:To investigate and compare the trophic structures of hydrothermal vent communities at different depths, the carbon and nitrogen stable isotope ratios of dominant species were analyzed in the communities at Myojin Knoll (1,220-1,360 m) in the Izu-Ogasawara Arc and the Nikko Seamount (380-550 m) in the North Mariana Arc. At the Myojin knoll, a barnacle, Ashinkailepas seepiophila had high δ 15 N value, which suggested to be derived from photosynthetic products. Similarly, at Nikko Seamount, a polynoid polychaete, Gandulfus yunohana, a xanthid crab, Alvinocaaris sp., and Symphurus thermophilus had high δ 15 N values. These animals, too, are suggested to consume photosynthetic products. The range of δ 13 C values at Myojin Knoll was wider than that at Nikko Seamount. The difference between the ranges of these values suggest that different chemical environments between the two vent sites influence the components and distribution of chemoautotrophic bacteria found at each site, leading to different faunal compositions.

Trophic structure of the macrofauna associated to deep-vents of the southern Gulf of California: Pescadero Basin and Pescadero Transform Fault

“…7 from PB. Such low values probably reflect the effect of isotopic fractionation by the enzymes of the endosymbionts lodged in their gills [35,36]. Low values were also observed in the tubeworms E .…”

“…Actiniarids from the periphery of the vent fields share positive δ 15 N values, although they seem to occasionally profit from the vent community byproducts [40]. Non-vent deep-sea fauna usually has higher δ 15 N values than vent-fauna [22,23,36,41]. Values between 14.5‰ and 17.9‰ were recorded in non-vent organisms collected near the vents of the Guaymas Basin [23].…”

Hydrothermal activity lowers trophic diversity in Antarctic hydrothermal sediments

“…B. Bell et al: Hydrothermal activity lowers trophic diversity 5719 (−20.5 ‰ ± 1.0 ‰) was depleted in δ 13 C relative to Southern Ocean DIC by around 10 ‰ (Henley et al, 2012;Young et al, 2013), giving it a signal within the fractionation range of the reverse tricarboxylic acid cycle (Yorisue et al, 2012), but the concentration and isotopic composition of DIC can undergo considerable alteration in hydrothermal sediments (Walker et al, 2008). Therefore, without measurements of δ 13 C in pore fluid DIC, it was not possible to determine which fixation pathway(s) were being used by S. contortum endosymbionts.…”

Hydrothermal activity lowers trophic diversity in Antarctic sedimented hydrothermal vents

“…Carbon isotopic signatures in chemosynthetic primary production depend upon the mode of fixation and the initial δ C of available DIC. Sclerolinum contortum δ 13 C (-20.52 ‰ ± 0.99) was depleted in δ 13 C relative to Southern Ocean DIC by around10 ‰ (Henley et al 2012, Young et al 2013, giving it a signal within the fractionation range of the reverse tricarboxyclic acid cycle (Yorisue et al 2012). Regional measurements of surface ocean DIC δ 13 C have an average isotopic signature of -10.37 ‰ (Henley et al 2012, Young et al 2013 but the concentration and isotopic composition of DIC can undergo considerable alteration at sedimented vents (Walker et al 2008) and consequently, may exhibit substantial variation in δ 13 C. Therefore, without measurements of δ 13 C in pore fluid DIC, it was not possible to determine which fixation pathway(s) were being used by S. contortum endosymbionts.…”