Helena Filipsson
Professor
Deglacial history of the Kattegat-Baltic Sea using x-ray micro-computed tomography of benthic foraminifera
Författare
Summary, in English
The Baltic Sea is strongly affected by the combined stressors of deoxygenation, acidification, and eutrophication. These are primarily derived from 1) anthropogenic CO2 emissions, which increase atmospheric temperatures, enhance surface water stratification, reduce oxygen solubility, and alter carbonate chemistry, and 2) nutrient pollution from the Baltic Sea’s heavily populated coastline. Together, these rapid environmental changes are significantly impacting fragile coastal ecosystems and dependent economies, yet the combined effects of multiple stressors are still not well understood. Paleoceanographic reconstructions of the Baltic Sea from past periods of rapid warming can provide benchmarks for and help predict future synergistic effects of multiple stressors as well as regional oceanographic responses to changes in global climate.
Our research uses a continuous, high-resolution sediment record of the last deglaciation (~18-15 ka) from the Kattegat seaway between Sweden and Denmark (IODP Expedition 347 Site M0060). Existing results for M0060 from benthic foraminiferal stable oxygen and carbon isotopes, trace elements, species assemblages, and a recalibrated age model support evidence of an early deglacial, poorly ventilated setting that undergoes freshening until ~15.5 ka, concomitant with the retreat of the proximal Fennoscandian Ice Sheet (FIS), followed by a transition to better ventilated, more saline conditions. We use synchrotron-based x-ray micro-computed tomography of benthic foraminiferal species Elphidium clavatum at decadal- to centennial-scale resolution to generate three-dimensional shell morphology (e.g., shell thickness, density, porosity, surface area/volume ratio). These morphometrics are expected to reflect bottom water environmental changes, likely controlled by the combined influence of adjacent FIS dynamics, European continent glacial meltwater, and North Atlantic circulation. Quantifying morphometric variability across the deglaciation will further constrain end-Pleistocene changes in temperature, oxygen, salinity, carbonate chemistry, and productivity, as well as disentangling the relative controls of regional ice-sheet and climate dynamics on the Baltic Sea from larger North Atlantic climate.
Our research uses a continuous, high-resolution sediment record of the last deglaciation (~18-15 ka) from the Kattegat seaway between Sweden and Denmark (IODP Expedition 347 Site M0060). Existing results for M0060 from benthic foraminiferal stable oxygen and carbon isotopes, trace elements, species assemblages, and a recalibrated age model support evidence of an early deglacial, poorly ventilated setting that undergoes freshening until ~15.5 ka, concomitant with the retreat of the proximal Fennoscandian Ice Sheet (FIS), followed by a transition to better ventilated, more saline conditions. We use synchrotron-based x-ray micro-computed tomography of benthic foraminiferal species Elphidium clavatum at decadal- to centennial-scale resolution to generate three-dimensional shell morphology (e.g., shell thickness, density, porosity, surface area/volume ratio). These morphometrics are expected to reflect bottom water environmental changes, likely controlled by the combined influence of adjacent FIS dynamics, European continent glacial meltwater, and North Atlantic circulation. Quantifying morphometric variability across the deglaciation will further constrain end-Pleistocene changes in temperature, oxygen, salinity, carbonate chemistry, and productivity, as well as disentangling the relative controls of regional ice-sheet and climate dynamics on the Baltic Sea from larger North Atlantic climate.
Avdelning/ar
- Geologiska institutionen
- BECC: Biodiversity and Ecosystem services in a Changing Climate
- Statistiska institutionen
Publiceringsår
2023-07
Språk
Engelska
Dokumenttyp
Affisch
Ämne
- Earth and Related Environmental Sciences
- Climate Science
Conference name
INQUA 2023
Conference date
2022-07-14 - 2023-09-21
Conference place
Rome, Italy
Aktiv
Published
Projekt
- Environmental changes in foraminiferal shell morphology revealed by synchrotron μCT