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Helena Filipsson, foto Erik Thor

Helena Filipsson

Professor

Helena Filipsson, foto Erik Thor

3D morphological variability in foraminifera unravel environmental changes in the Baltic Sea entrance over the last 200 years

Författare

  • Constance Choquel
  • Dirk Müter
  • Sha Ni
  • Behnaz Pirzamanbein
  • Laurie M. Charrieau
  • Kotaro Hirose
  • Yusuke Seto
  • Gerhard Schmiedl
  • Helena L. Filipsson

Summary, in English

Human activities in coastal areas have intensified over the last 200 years, impacting also high-latitude regions such as the Baltic Sea. Benthic foraminifera, protists often with calcite shells (tests), are typically well preserved in marine sediments and known to record past bottom-water conditions. Morphological analyses of marine shells acquired by microcomputed tomography (µCT) have made significant progress toward a better understanding of recent environmental changes. However, limited access to data processing and a lack of guidelines persist when using open-source software adaptable to different microfossil shapes. This study provides a post-data routine to analyze the entire test parameters: average thickness, calcite volume, calcite surface area, number of pores, pore density, and calcite surface area/volume ratio. A case study was used to illustrate this method: 3D time series (i.e., 4D) of Elphidium clavatum specimens recording environmental conditions in the Baltic Sea entrance from the period early industrial (the 1800s) to present-day (the 2010 s). Long-term morphological trends in the foraminiferal record revealed that modern specimens have ∼28% thinner tests and ∼91% more pores than their historic counterparts. However, morphological variability between specimens and the BFAR (specimens cm−2 yr−1) in E. clavatum were not always synchronous. While the BFAR remained unchanged, morphological variability was linked to natural environmental fluctuations in the early industrial period and the consequences of anthropogenic climate change in the 21st century. During the period 1940–2000 s, the variations in BFAR were synchronous with morphological variability, revealing both the effects of the increase in human activities and major hydrographic changes. Finally, our interpretations, based on E. clavatum morphological variations, highlight environmental changes in the Baltic Sea area, supporting those documented by the foraminiferal assemblages.

Avdelning/ar

  • Kvartärgeologi
  • Geologiska institutionen
  • MERGE: ModElling the Regional and Global Earth system
  • Statistiska institutionen

Publiceringsår

2023

Språk

Engelska

Publikation/Tidskrift/Serie

Frontiers in Earth Science

Volym

11

Dokumenttyp

Artikel i tidskrift

Förlag

Frontiers Media S. A.

Ämne

  • Natural Sciences
  • Climate Research
  • Oceanography, Hydrology, Water Resources
  • Environmental Sciences
  • Geology

Nyckelord

  • 3D reconstructions
  • environmental change
  • foraminifera
  • morphological variability
  • synchrotron-light
  • tomography

Aktiv

Published

ISBN/ISSN/Övrigt

  • ISSN: 2296-6463