november, 2017

30nov1:00 pm2:00 pmSediment traps as tools to assess the seasonal trends of pelagic amphipods in the Northern Scotia SeaHarry Gunning1:00 pm - 2:00 pm Lecture Theatre D, Bute Building

Event Details

Within the Southern Ocean, the Northern Scotia Sea contains the largest seasonal uptake of atmospheric carbon dioxide measured yet. In this region, zooplankton can contribute significantly to the deep ocean carbon export and to the food web. However, year-round data for zooplankton abundance in this region are rare, due to the current difficulty of sampling in the austral winter using conventional sampling methods, such as plankton net tows. Moored time-series sediment traps are primarily used to gather information on vertical particle fluxes in the oceans. However, the accidental capture of zooplankton (so called ‘swimmers’) in time-series moored sediment traps deployed year-round provides a unique and much-needed insight into the seasonal variation of zooplankton abundance and diversity in remote areas such as the Southern Ocean. In this study, we show results of pelagic amphipods collected as swimmers from two years (2015-2016) of moored sediment trap deployment at 400m, located in a site in the Northern Scotia Sea close to South Georgia (SCOOBIES mooring platform). Amphipods represent a key link in the food web between meso-zooplankton and higher trophic organisms. Organisms were counted, photographed and measured using Image J software. Dry mass and carbon content were indirectly calculated. In both investigated years, Amphipod numbers reached the seasonal peak in the austral late summer-early autumn, decreasing until the next summer season. A shift in Amphipod assemblage composition was observed in both 2015 and 2016 with Hyperiidea and Gammaridea dominating the total Amphipod assemblage in the austral winter and summer respectively. The data presented, serves as a baseline for future research to explore the opportunity of using sediment traps as tools to monitoring seasonal and inter-annual variability of zooplankton in the Southern Ocean.

Time

(Thursday) 1:00 pm - 2:00 pm

Location

Lecture Theatre D, Bute Building

KY16 9TS

Organizer

Prof Andy BrierleySchool of Biology, Unvieristy of St Andrews asb4@st-andrews.ac.uk

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