Spatial distribution of microzooplankton in different areas of the northern Antarctic Peninsula region, with an emphasis on tintinnids

Marina Monti-Birkenmeier,Anne-Christin Schulz,Thomas H Badewien,Anna Friedrichs,Tommaso Diociaiuti,Bettina Meyer

doi:10.1007/s00300-021-02910-8

Abstract

The Western Antarctic Peninsula (WAP) is experiencing rapid climate warming, resulting in affecting the marine food web. To investigate the microzooplankton spatial distribution and to assess how climate change could affect the tintinnids community, sea water samples were collected during late summer 2018 at 19 stations in three different areas: Deception Island, Elephant Island and Antarctic Sound. The microzooplankton community comprised mainly tintinnids, aloricate ciliates, heterotrophic dinoflagellates and micrometazoans. Microzooplankton abundance varied between 3 and 109 ind. L−1 and biomass ranged from 0.009 to 2.55 µg C L−1. Significant differences in terms of abundance and taxonomic composition of microzooplankton were found among the three sampling areas. Deception Island area showed 44% of tintinnids and the rest were heterotrophic dinoflagellate, aloricate ciliates and micrometazoans. In Elephant Island and Antarctic Sound areas, tintinnids reached, respectively, 73% and 83% of the microzooplankton composition, with all the other groups varying between 20 and 30%. Tintinnids were the most representative group in the area, with the species Codonellopsis balechi, Codonellopsis glacialis, Cymatocylis convallaria and Cymatocylis drygalskii. The highest amounts of tintinnids were found at the surface and 100 m depth. The above mentioned species may be considered key species for the WAP and therefore they can be used to track environmental and hydrographical changes in the area. In late summer, microzooplankton presented low abundances and biomass, nevertheless they represented an important fraction of the planktonic community in the area.

Highlights

The Western Antarctic Peninsula (WAP) is one of the fastest warming areas on the planet, making this part of the Southern Ocean an invaluable observatory of ecosystem responses to climate change (Ducklow et al 2012)
Water temperature varied from − 1.85 °C (Antarctic Sound, St. 81 at 10 m) to 2.05 °C (Deception Island, St. 34 at 500 m) (Fig. 2)
Antarctic Sound showed the highest presence of Codonellopsis balechi and L. naviculaefera, while Elephant Island was characterized by higher abundance of Codonellopsis glacialis, Cymatocylis convallaria and Cymatocylis vanhöffeni

Summary

Introduction

The Western Antarctic Peninsula (WAP) is one of the fastest warming areas on the planet, making this part of the Southern Ocean an invaluable observatory of ecosystem responses to climate change (Ducklow et al 2012). The warming in the region has resulted in shorter winter sea ice, increase in surface water temperature, melting of glaciers and glacial runoff (Whitehouse et al 2008; Turner et al 2009) These environmental changes have been shaping the distribution of phytoplankton biomass over the WAP region. The changing phytoplankton composition and chlorophyll a trend (Montes-Hugo et al 2009) in the northern WAP promotes the decline in diatoms abundances and the contextual increase in abundance of smaller organisms, resulting in the dominance of nanophytoplankton (Mendes et al 2013; Sangrà et al 2014; Garcia et al 2019) This last evidence can affect the distribution and community composition of microzooplankton, as well as higher trophic levels

Methods

Results

Discussion

Conclusion