Short term responses of Arctic deep-sea benthic macrofauna to pulses of phytodetritus.

URSULA WITTE; PHILIPPE ARCHAMBAULT; BRAVO GONZALO; GEORGEOS KAZANIDIS; CHRISTIAN NOZAIS; JAVIER CIANCIO; SOLVEIG BOURGEOIS

Myrtle Beach, South Caroline (USA)

Congreso; Benthic Ecology Meeting; 2017

Deep-sea benthic ecosystems of theArctic Ocean are fuelled by organic material originating from the water column.Where sea ice is present, this organic material can take the form of ice algaeand phytoplankton. So far, little is known about the responses of macrofaunafacing future changes regarding quantity and quality of food reaching theseafloor inflicted by sea ice reduction. We conducted on-board enrichmentexperiments with sediment cores collected from boxcores casts (680 m depth) inBaffin Bay to investigate the macrofauna and bacterial incorporation of twodifferent 13C-labeled phytodetritus sources (phytoplankton: Thalassiosiranordenskioeldii and ice algae: Synedra hyperborea). A total of 28taxa were recorded in cores. Agglutinated foraminiferans were the mostimportant in terms of abundance and biomass, followed by bivalves andpolychaetes. No significant differences were found in abundance and biomass ofmacrofauna between treatments (control, ice algae and phytoplankton) which makepossible the comparisons of 13C incorporation among them. Data from these coresincubations experiences could provide useful information to anticipate effectsof climate change on Arctic benthic communities.