Temporal variability in foraminiferal morphology and geochemistry at the West Antarctic Peninsula: A sediment trap study

Anna Mikis, Katharine R. Hendry*, Jennifer Pike, Daniela N. Schmidt, Kirsty M. Edgar, Victoria Peck, Frank J.C. Peeters, Melanie J. Leng, Michael P. Meredith, Chloe L. Todd, Sharon Stammerjohn, Hugh Ducklow

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The West Antarctic Peninsula (WAP) exhibits strong spatial and temporal oceanographic variability, resulting in highly heterogeneous biological productivity. Calcifying organisms that live in the waters off the WAP respond to temporal and spatial variations in ocean temperature and chemistry. These marine calcifiers are potentially threatened by regional climate change with waters already naturally close to carbonate undersaturation. Future projections of carbonate production in the Southern Ocean are challenging due to the lack of historical data collection and complex, decadal climate variability. Here we present a 6-yearlong record of the shell fluxes, morphology and stable isotope variability of the polar planktic foraminifera Neogloboquadrina pachyderma (sensu stricto) from near Palmer Station, Antarctica. This species is fundamental to Southern Ocean planktic carbonate production as it is one of the very few planktic foraminifer species adapted to the marine polar environments We use these new data to obtain insights into its ecology and to derive a robust assessment of the response of this polar species to environmental change. Morphology and stable isotope composition reveal the presence of different growth stages within this tightly defined species. Inter- and intra-annual variability of foraminiferal flux and size is evident and driven by a combination of environmental forcing parameters, most importantly food availability, temperature and sea ice duration and extent. Foraminiferal growth occurs throughout the austral year and is influenced by environmental change, a large portion of which is driven by the Southern Annular Mode and El Ni o-Southern Oscillation. A distinct seasonal production is observed, with the highest shell fluxes during the warmest and most productive months of the year. The sensitivity of calcifying foraminifera to environmental variability in this region, from weeks to decades, has implications both for their response to future climatic change and for their use as palaeoclimate indicators. A longer ice-free season could increase carbonate production in this region at least while carbonate saturation is still high enough to allow for thick tests to grow.

Original languageEnglish
Pages (from-to)3267-3282
Number of pages16
JournalBiogeosciences
Volume16
Issue number16
DOIs
Publication statusPublished - 30 Aug 2019

Funding

Financial support. Anna Mikis was supported by a Cardiff University President’s Scholarship, and the stable isotope analysis was funded by an Antarctic Science Ltd. International Bursary awarded to Anna Mikis. The sediment trap time series has been funded by a series of awards from the US NSF Office of Polar Programs, including award PLR-1440435 to Hugh Ducklow. Katharine R. Hendry is funded by a Royal Society University Research Fellowship (grant no. UF120084), and Daniela N. Schmidt is supported by a Royal Society Wolfson Merit Award. Kirsty M. Edgar was supported by a Leverhulme Trust Early Career Fellowship.

FundersFunder number
Antarctic Science Ltd
National Science Foundation
Directorate for Geosciences9011927, 1440435, 9632763, 0823101, 0217282
Office of Polar ProgramsPLR-1440435
Natural Environment Research CouncilNE/M013782/1, bas0100033, bas0100030
Leverhulme Trust
Royal SocietyUF120084
Cardiff University

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