The Baltic Sea has experienced a complex ecological history since the last glacial maximum (~18,000 years ago). Changes to its oceanic connection to the Atlantic, tectonic uplift of northern Europe and varying river input have changed the Baltic's salinity,
nutrient content and primary productivity. This study compares several records of these environmental changes, a “multiproxy” approach, in order to provide a robust chronology of ecological changes.
This kind of multiproxy study is valuable for two main reasons. First, conclusions from one record can be verified by the others. Second, the magnitude of changes from each record can be compared, allowing researchers to understand the sensitivity of
each data type to climate and environmental change. An international team of scientists analyzed sediments, inorganic and organic geochemistry, pollen and other palynomorphs, ostracods, foraminifera and diatoms. By using this suite of proxies, the
authors were able to reconstruct changes to salinity, nutrients, primary productivity, sea ice, and sea surface temperature. This study is also significant in that the samples were collected from the “Little Belt” region, one of the connections between
the Atlantic and the Baltic. This allows researchers to understand the influence of the Atlantic on the Baltic over time. The study covers the time before agriculture was present on the Norwegian peninsula through early farming to modern industrialization,
allowing for an understanding of human influence on the Baltic system as well.
Citation: Kotthoff, U., Groeneveld, J., Ash, J. L., Fanget, A.-S., Krupinski, N. Q., Peyron, O., Stepanova, A., Warnock, J., Van Helmond, N. A. G. M., Passey, B. H., Clausen,
O. R., Bennike, O., Andrén, E., Granoszewski, W., Andrén, T., Filipsson, H. L., Seidenkrantz, M.-S., Slomp, C. P., and Bauersachs, T.: Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison
from the Little Belt (IODP Expedition 347, Site M0059), Biogeosciences, 14, 5607-5632, https://doi.org/10.5194/bg-14-5607-2017, 2017.