Biological characteristics of a hydrothermal edifice mosaic community
Date
1999
Authors
Sarrazin, J.
Juniper, S. Kim
Journal Title
Journal ISSN
Volume Title
Publisher
Marine Ecology Progress Series
Abstract
study defines the composition and biomass charactenstics of 5 of 6 previously
described faunal assemblages that form a mosaic community on hydrothermal sulfide edifices of the
Juan de Fuca Ridge (northeast Pacific). Quantitative samples of each assemblage were acquired during
'ROPOS' Remote Operated Vehicle (ROV) dive programs in 1994 and 1996. Total abundance, and
species nchness, as well as wet and dry weights, were calculated for each assemblage, and sampled
surface area was measured directly or from scaled images of sample scars. These data were used to
compare species composition, nchness and biomass of the distinct assemblages and to estimate total
biomass of a sulfide edifice. In addition to major compositional differences. we observed an increase in
density, biomass and species richness along a proposed successional sequence from the Paralvinella
suifincola (annelid polychaete) assemblage (Assemblage I) to the low-flow Ridgeia piscesae (vestimentifera)
community (Assemblage V-LF). Biomass (dry weight without vestimentiferan tubes) of the
different sampled assemblages ranged from 0.011 kg m-2 for Assemblage I to 4.68 kg m-2 for Assemblage
V-LF and 2.33 kg m-2 for the rarer high-flow Ridgeia pjscesae community (V-HF). Resulting
quantitative information was used to refine a previous model of community succession. Comparisons
with other manne ecosystems showed that the biomass of these and other hydrothermal assemblages
dominated by symbiont-bearing organisms (vestimentifera, bivalvia) is sirnilar to those found in the
most productive photosynthetically based assemblages. Tubeworm growth and sulfide accretion
greatly increase total surface area available to vent organisms, and may attenuate competition for
space. The 3-dimensional habitat formed by Ridgeia piscesae tubes may influence species distribution
and enhance species nchness. The tube worm assemblages comprise the major and probably the most
stable component of total edifice biomass. At one site, over a 4 yr period, there was substantial environmental
change and major shifts in coverage by other assemblages but relatively little change in total
coverage by R. piscesae. As a result total edifice biomass (219 to 251 kg dry weight) varied by only 16 %
over 1 to 3 yr intervals. Considerable quantitative ecological information can be derived from analyses
of submersible-collected imagery, with sampling serving pnmanly as a ground truthing tool. Limitations
of sampling and surface area determinations are considered.
Description
Keywords
Vent ecology, Biomass, Faunal succession, Sulfide edifice, Assemblage characteristics, Image analysis, Juan de Fuca Ridge, Ecological model, Marine ecosystem biomass
Citation
Sarrazin, J. & Juniper, S.K. (1999). Biological characteristics of a hydrothermal edifice mosaic community, Marine Ecology Progress Series, 185. http://doi.org/10.3354/meps185001