Helena Filipsson
Professor
Holocene Hydrographic Variations From the Baltic-North Sea Transitional Area (IODP Site M0059)
Författare
Summary, in English
Deoxygenation affects many continental shelf seas across the world today and results in increasing areas of hypoxia (dissolved oxygen concentration ([O2]) <1.4 ml/L). The Baltic Sea is increasingly affected by deoxygenation. Deoxygenation correlates with other environmental variables such as changing water temperature and salinity and is directly linked to ongoing global climate change. To place the ongoing environmental changes into a larger context and to further understand the complex Baltic Sea history and its impact on North Atlantic climate, we investigated a high accumulation-rate brackish-marine sediment core from the Little Belt (Site M0059), Danish Straits, NW Europe, retrieved during the Integrated Ocean Drilling Program (IODP) Expedition 347. We combined benthic foraminiferal geochemistry, faunal assemblages, and pore water stable isotopes to reconstruct seawater conditions (e.g., oxygenation, temperature, and salinity) over the past 7.7 thousand years (ka). Bottom water salinity in the Little Belt reconstructed from modeled pore water oxygen isotope data increased between 7.7 and 7.5 ka BP as a consequence of the transition from freshwater to brackish-marine conditions. Salinity decreased gradually (from 30 to 24) from 4.1 to ~2.5 ka BP. By using the trace elemental composition (Mg/Ca, Mn/Ca, and Ba/Ca) and stable carbon and oxygen isotopes of foraminiferal species Elphidium selseyensis and E. clavatum, we identified that generally warming and hypoxia occurred between about 7.5 and 3.3 ka BP, approximately coinciding in time with the Holocene Thermal Maximum (HTM). These changes of bottom water conditions were coupled to the North Atlantic Oscillation (NAO) and relative sea level change.
Avdelning/ar
- Centrum för miljö- och klimatvetenskap (CEC)
- Kvartärgeologi
- BECC: Biodiversity and Ecosystem services in a Changing Climate
- Berggrundsgeologi
Publiceringsår
2020-02-01
Språk
Engelska
Publikation/Tidskrift/Serie
Paleoceanography and Paleoclimatology
Volym
35
Issue
2
Dokumenttyp
Artikel i tidskrift
Förlag
Wiley-Blackwell
Ämne
- Oceanography, Hydrology, Water Resources
- Geology
Nyckelord
- foraminifera
- Holocene Thermal Maximum
- LA-ICP-MS
- NAO
- Skagerrak
- trace elements
Aktiv
Published
Projekt
- Tracing marine hypoxic conditions during warm periods using a microanalytical approach
- Tracing hypoxia during warm periods in the Baltic Sea region - using synchrotron X-ray spectroscopy and plasma analytical methods
ISBN/ISSN/Övrigt
- ISSN: 2572-4517