An extensive v~deoscopics tudy of a h~gh- temperatures ulfide structure on the Juan d e
Fuca Rldge (northeast Pacific) examined temporal variation in vent community distnbution and l~nks
between faunal and environmental changes V~ d e oim agery was acquired d u l ~ n ga total of 5 manned
submersible and ROV (remotely-operated vehicle) dive programs between 1991 and 1995 The structure
was systemat~callym apped for each year of the study and a serles of analytical tools was developed
to quantify changes in biological and geological features and observable flow patterns Results
shoiv (l) heterogeneous faunal distnbution, characterized by decimeter-scale patchiness and general
absence of vertical gladients, (2) apparent links between commun~tyd ~s tnbut iona, nd environmental
features such as fluid flow patterns, substratum and temperature/chemicdl conditions, (3) a significant
influence of perturbations on community dynamics, (4) dbsence of d ~ r e c t ~ o nbailo logical succession at
the time scale examlned (years) Overall, these observations strongly suggest that many hydrothermal
community changes are initiated by gradual and ablupt flow mod~fications Results are compiled in a
dynamic succession model for sulfide edifices where community transitions are dnven by flow vanatlons,
and by biolog~calp rocesses operating at sub-annual t ~ m esc ales CVe conclude by stressing the
need for extended momtonng of short-term dynamics in order to understand the relationslup between
hydrothermal communities and their environment.Thls work would not have been posslble
wthout the field support by the pdots of ROPOS, Alvln and
Jason and the crews of the CSS 'John P. Tully' and the RV
'Atlantis 11'. This research was sponsored by NSERC-Canada,
Fisheries and Oceans Canada and the National Science Foundation
J S was supported by post-graduate fellowships from
NSERC (Canada) FCAR (Quebec) and CEOTOP (UQAM)
We are particuldrly grateful to Dr Pierre Legendre for h ~ hse lp
with canonical analyses and to Drs Verena Tunnicllffe and
Margaret Tlvey for the11 suggestions and comments on the
manuscnpt Dr Mark Hannington klndly provided drawlngs
of S&M from 1991 Jason and Alvin Imagery, and Enriette
Gagnon aided in drafting of Fig 3 The UQAM Decanat des
Etudes Avancees, provlded support for pubhcatlon of color
figures Four anonymous reviewers are thanked for their constructlve
inputFacultyReviewe
