Publikationsdatum:
2018-02-23
Beschreibung:
Knowledge of the processes shaping deep-sea benthic communities at seasonal scales in
cold-seep environments is incomplete. Cold seeps within highly dynamic regions, such as
submarine canyons, where variable current regimes may occur, are particularly understudied.
Novel Internet Operated Vehicles (IOVs), such as tracked crawlers, provide new techniques
for investigating these ecosystems over prolonged periods. In this study a benthic
crawler connected to the NEPTUNE cabled infrastructure operated by Ocean Networks
Canada was used to monitor community changes across 60 m2 of a cold-seep area of the
Barkley Canyon, North East Pacific, at ~890 m depth within an Oxygen Minimum Zone
(OMZ). Short video-transects were run at 4-h intervals during the first week of successive
calendar months, over a 14 month period (February 14th 2013 to April 14th 2014). Within
each recorded transect video megafauna abundances were computed and changes in environmental
conditions concurrently measured. The responses of fauna to environmental conditions
as a proxy of seasonality were assessed through analysis of abundances in a total of
438 video-transects (over 92 h of total footage). 7698 fauna individuals from 6 phyla (Cnidaria,
Ctenophora, Arthropoda, Echinodermata, Mollusca, and Chordata) were logged and
patterns in abundances of the 7 most abundant taxa (i.e. rockfish Sebastidae, sablefish
Anoplopoma fimbria, hagfish Eptatretus stoutii, buccinids (Buccinoidea), undefined small
crabs, ctenophores Bolinopsis infundibulum, and Scyphomedusa Poralia rufescens) were
identified. Patterns in the reproductive behaviour of the grooved tanner crab (Chionnecetes
tanneri) were also indicated. Temporal variations in biodiversity and abundance in megabenthic
fauna was significantly influenced by variabilities in flow velocity flow direction (up or
down canyon), dissolved oxygen concentration and month of study. Also reported here for
the first time are transient mass aggregations of grooved tanner crabs through these depths
of the canyon system, in early spring and likely linked to the crab's reproductive cycle.
Repository-Name:
EPIC Alfred Wegener Institut
Materialart:
Article
,
peerRev
Format:
application/pdf
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