Regional variability of diatoms in ice cores from the Antarctic Peninsula and Ellsworth Land, Antarctica

Dieter R Tetzner,Elizabeth R Thomas,Claire S Allen

doi:10.5194/tc-16-779-2022

Abstract

Abstract. The presence of marine microfossils (diatoms) in glacier ice and ice cores has been documented from numerous sites in Antarctica, Greenland, as well as from sites in the Andes and the Altai mountains, and attributed to entrainment and transport by winds. However, their presence and diversity in snow and ice, especially in polar regions, are not well documented and still poorly understood. Here we present the first data to resolve the regional and temporal distribution of diatoms in ice cores, spanning a 20-year period across four sites in the Antarctic Peninsula and Ellsworth Land, Antarctica. We assess the regional variability in diatom composition and abundance at annual and sub-annual resolution across all four sites. These data corroborate the prevalence of contemporary marine diatoms in Antarctic Peninsula ice cores, reveal that the timing and amount of diatoms deposited vary between low- and high-elevation sites, and support existing evidence that marine diatoms have the potential to yield a novel palaeoenvironmental proxy for ice cores in Antarctica.

Highlights

Diatoms are unicellular algae with siliceous cell walls that inhabit aquatic environments throughout the world (Smol and Stoermer, 2010)
Regional diatom ecology reveals that the diatom record preserved in ice cores from the southern Antarctic Peninsula (AP) and Ellsworth Land (EL) was prevalently conformed by marine taxa abundant in the Southern Ocean (SO) (Crosta et al, 2005; Zielinski and Gersonde, 1997; RigualHernández et al, 2015)
These findings support SO surface waters as the principal source of diatoms and aeolian transport as the mechanism to transfer diatoms to the AP and EL ice core sites. This is consistent with previous studies showing that air masses originating in the SO are transported within days to the AP and EL ice core sites (Thomas and Bracegirdle, 2015; Allen et al, 2020)

Summary

Introduction

Diatoms are unicellular algae with siliceous cell walls that inhabit aquatic environments throughout the world (Smol and Stoermer, 2010). Diatoms are sensitive to oceanographic conditions and responsive to environmental changes. When diatoms die, they sink, promoting carbon export from the sea surface to deep waters. These characteristics make them valuable as proxies for palaeoenvironmental and palaeoceanographic reconstructions (Smol and Stoermer, 2010) Despite their aquatic habitats, several studies support they can be airborne (Lichti-Federovich, 1984; Gayley et al, 1989; Chalmers et al, 1996; McKay et al, 2008; Wang et al, 2008; Harper and Mckay, 2010; Spaulding et al, 2010; Hausmann et al, 2011; Budgeon et al, 2012; Papina et al, 2013; Fritz et al, 2015; Marks et al, 2019). Airborne diatoms can be deposited over ice sheets (Budgeon et al, 2012; Allen et al, 2020) and buried under subsequent snowfall events to become part of the ice matrix

Methods

Results

Discussion

Conclusion