SPATIAL ANALYSIS OF ZOOPLANKTON FECAL PELLET CARBON EXPORT IN THE WEST ANTARCTIC PENINSULA

Zooplankton fecal pellets play a significant role in the ocean biological carbon pump through the export of carbon out of the surface ocean. Limited research has been completed in the West Antarctic Peninsula (WAP) on the contribution of fecal pellets to export. As one of the fastest-warming places in the world, the WAP is experiencing rapid ecological change, and understanding trends in fecal pellet carbon export is critical for predicting the future of biogeochemical processes in this region. Fecal pellet export was measured using drifting sediment trap arrays during austral summer 2023 – 2024 on the annual Palmer, Antarctica Long-Term Ecological Research (PAL LTER) cruise. Zooplankton-mediated fecal pellet carbon export was calculated for two sites on the coast of the WAP, and comparisons were made between site locations and sediment trap collection depths. Image analysis was used to measure pellets and calculate fecal pellet volume, which was converted to carbon using published carbon to volume ratios. Total fecal pellet carbon export was higher in the northern coastal site than in the southern coastal site. Additionally, cylindrical pellet export from krill contributed a larger proportion of the total fecal pellet flux in the northern site. Export of ovoid fecal pellets, likely from copepods, significantly increased with increasing depth at the northern site. This research provides the first spatial analysis of zooplankton fecal pellet export in the WAP and highlights the role of zooplankton community structure and fecal pellet export in the biological carbon pump.

Presentation Preference: Oral

Primary Presenter: Sachi Anand, Brandeis University (sachisanand@gmail.com)

Authors:

Sachi Anand, Brandeis University  (sachisanand@gmail.com)

Maya Thomas, Virginia Institute of Marine Science  (mithomas@vims.edu)

Deborah Steinberg, Virginia Institute of Marine Science  (debbies@vims.edu)