Chemistry, temperature, and faunal distributions at diffuse-flow hydrothermal vents : comparison of two geologically distinct ridge systems

Author Posting. © The Oceanography Society, 2012. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 25, no. 1 (2012): 234–245, doi:10.5670/oceanog.2012.22.Diffuse-flow, low-temperature areas near hydrothermal vents support life via chemosynthesis: hydrogen sulfide (and other reduced chemical compounds) emanating from the subsurface is oxidized with bottom-water oxygen through bacterial mediation to fix carbon dioxide and produce biomass. This article reviews the in situ diffuse-flow chemistry (mainly H2S and O2) and temperature data collected in 2006 and 2009 along the Eastern Lau Spreading Center (ELSC), and from 2004 to 2008 at 9°N along the East Pacific Rise (9 N EPR), predominantly around macrofauna that contain endosymbionts at these two hydrothermal vent regions. More than 48,000 and 20,000 distinct chemical and temperature data points were collected with a multi-analyte electrochemical analyzer in the diffuse-flow waters at 9 N EPR and the ELSC, respectively. Despite their different geological settings and different macrofauna (two different species of snails and mussels at the ELSC versus two different species of tubeworms and mussels at 9 N EPR), there are similarities in the temperature and chemistry data, as well as in the distributions of organisms. The pattern of water chemistry preferred by the provannid snails (Alviniconcha spp., Ifremeria nautilei) and Bathymodiolus brevior at the ELSC is similar to the water chemistry pattern found for the siboglinid tubeworms (Tevnia jerichonana, Riftia pachyptila) and the Bathymodiolus thermophilus mussels at 9 N EPR. The eruptions at 9 N EPR in 2005 and 2006 resulted in increased H2S concentrations, increased H2S/T ratios, and an initial change in the dominant tubeworm species from Riftia pachyptila to Tevnia jerichonana after the eruption created new vent habitats. In 2005, two sites at 9 N EPR showed major increases in the H2S/T ratio from 2004, which suggested a probable eruption in this basalt-dominated system. At the ELSC, there was a decrease in the H2S/T ratio from northern to southern sites, which reflects the change in geological setting from basalt to andesite and the shallower water depths at the southern sites.This work was supported by NSF grants OCE-0240896, OCE-073243 (ELSC), OCE-0308398 (OTIC), OCE-0326434, and OCE-0937324 (EPR) to GWL; ESI-0087679, OCE-9529819, and OCE-0327353 to RAL; OCE-0327261, OCE-0328117, OCE-0451983 to TMS; and OCE 0240985 and OCE 0732333 to CRF

Functions of height and width dimensions in the intertidal mussel, Mytilus californianus

Author Posting. © National Shellfisheries Association, 2008. This article is posted here by permission of National Shellfisheries Association for personal use, not for redistribution. The definitive version was published in Journal of Shellfish Research 27 (2008): 385-392, doi:10.2983/0730-8000(2008)27[385:FOHAWD]2.0.CO;2.A mussel's shell records its history of growth. We investigated variability in the size and shape of mussel shells of Mytilus californianus Conrad (1837) to test the hypothesis that the mussel shell provides information on the contemporary condition of the mussel. Two factors were associated with shape: an epithelial discoloration and the Sr/Ca in the shell nacre. Sr/Ca data distinguished the mussel populations as did a discriminate analysis that included the trace metal ratios; Sr/Ca, Mg/Ca, Mn/Ca, Ag/Ca, Cd/Ca, Ba/Ca, and Pb/Ca. Size varied independently of shape and was not associated with the two factors. However, a null model that describes the morphological variability in height and width suggests that mussel size also plays a central role in partitioning phenotypic variability. These analyses of contemporary factors coupled with analyses of morphological variability holds promise for addressing the functional roles of mussel height and width and what proportion of phenotypic variability can be attributed to environmental factors

Chemistry, Temperature, and Faunal Distributions at Diffuse-Flow Hydrothermal Vents: Comparison of Two Geologically Distinct Ridge Systems

Diffuse-flow, low-temperature areas near hydrothermal vents support life via chemosynthesis: hydrogen sulfide (and other reduced chemical compounds) emanating from the subsurface is oxidized with bottom-water oxygen through bacterial mediation to fix carbon dioxide and produce biomass. This article reviews the in situ diffuse-flow chemistry (mainly H2S and O2) and temperature data collected in 2006 and 2009 along the Eastern Lau Spreading Center (ELSC), and from 2004 to 2008 at 9°N along the East Pacific Rise (9 N EPR), predominantly around macrofauna that contain endosymbionts at these two hydrothermal vent regions. More than 48,000 and 20,000 distinct chemical and temperature data points were collected with a multi-analyte electrochemical analyzer in the diffuse-flow waters at 9 N EPR and the ELSC, respectively. Despite their different geological settings and different macrofauna (two different species of snails and mussels at the ELSC versus two different species of tubeworms and mussels at 9 N EPR), there are similarities in the temperature and chemistry data, as well as in the distributions of organisms. The pattern of water chemistry preferred by the provannid snails (Alviniconcha spp., Ifremeria nautilei) and Bathymodiolus brevior at the ELSC is similar to the water chemistry pattern found for the siboglinid tubeworms (Tevnia jerichonana, Riftia pachyptila) and the Bathymodiolus thermophilus mussels at 9 N EPR. The eruptions at 9 N EPR in 2005 and 2006 resulted in increased H2S concentrations, increased H2S/T ratios, and an initial change in the dominant tubeworm species from Riftia pachyptila to Tevnia jerichonana after the eruption created new vent habitats. In 2005, two sites at 9 N EPR showed major increases in the H2S/T ratio from 2004, which suggested a probable eruption in this basalt-dominated system. At the ELSC, there was a decrease in the H2S/T ratio from northern to southern sites, which reflects the change in geological setting from basalt to andesite and the shallower water depths at the southern sites