Agricultural activity and its impact on terrestrial and marine ecosystems in the Baltic Sea region during the past 6000 years
Final Report Abstract
Agricultural activity in coastal areas of the Baltic region could be identified and to some degree characterized based on cereal pollen grains. First consistent occurrences of taxa like wheat and rye could be dated – with age-model-related uncertainties – to 1100 to 800 cal yr in the southwestern (Little Belt) and to 700 to 550 cal yr BP in the central Baltic Sea (Landsort Deep). For the southwestern Baltic region, agricultural activity seems to be synchronous with an increase in brackish diatoms. Radiosperma increases strongly in the central and occurs more frequently in the northern Baltic Sea (Ångermanälven Estuary) in intervals when cereals are present. Potential decreases of testate amoebae during intervals of agricultural activity need more research. Deforestation in context with presence of cultured Poaceae can be postulated for the southwestern and central Baltic region. In these regions agricultural activity seems occur roughly at the same time when water temperatures and anoxic conditions are decreasing/weakening after warmer conditions linked to the medieval climate optimum. In some aspects the original work plan was altered – less temporal resolution was achieved, but more palynomorphs were differentiated and counted. A few of the research questions could not be answered in detail during the runtime of the project, but at least some of them shall be dealt with in follow up research, particularly for two sites in the region the Ångermanälven Estuary for which additional samples shall be analyzed in 2021/2022.
Publications
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(2019): Middle and Late Holocene variations in salinity and primary productivity in the central Baltic Sea: A multiproxy study from the Landsort Deep (IODP Expedition 347, Site M0063). Frontiers in Marine Science 6, 1-22
van Wirdum, F., Andrén, E., Wienholz, D., Kotthoff, U., Moros, M., Fanget, A.-S., Seidenkrantz, M.-S., Andrén, T.
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(2021): Holocene palaeoenvironmental conditions in the Baltic: reconstructions based on palynological and biogeochemical data from IODP Expedition 347, Site M0063 (Landsort Deep). GeoKarlsruhe (DGGV) (online)
Kotthoff U., Bauersachs, T.
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(2021): Reconstructing Holocene palaeoenvironmental conditions in the Baltic: Palynological and biogeochemical data from the Landsort Deep (IODP Expedition 347, Site M0063). European Geoscience Union Meeting 2021 (online)
Kotthoff U., Bauersachs, T.
