Echoes from the Past: A Healthy Baltic Sea Requires More Effort

Abstract

Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly. Under future IPCC scenarios of global warming, there is likely no improvement of bottom water conditions in the Baltic Sea. Thus, the measures already designed to produce a healthier Baltic Sea are insufficient in the long term. The interactions between climate change and anthropogenic impacts on the Baltic Sea should be considered in management, implementation of policy strategies in the Baltic Sea environmental issues, and adaptation to future climate change.

Changes in the inflow of saline water into the Bornholm Basin (SW Baltic Sea) during the past 7100 years – evidence from benthic foraminifera record

“…A similar pattern has been reported for the Gotland Basin by Kotilainen et al . (). The appearance of benthic foraminifera in the fossil record marks the time intervals when oxygenated bottom waters with salinities higher than 11–12 PSU occurred at the study site (Lutze ).…”

“…; Kotilainen et al . ). In subsection LS4, a gradual increase in foraminiferal abundance between c. 2.25 and 1.55 cal.…”

“…Notably, the inflows clearly seen in the Bornholm Basin during the peak of the MCA were not strong enough to reach the Gotland Basin (Kotilainen et al . ). However, the authors assigned more frequent and strong inflows to a climate transition between the MCA and the LIA linked to the changes in North Atlantic Oscillation (Kotilainen et al .…”

“…To our knowledge only Brodniewicz (), Lutze (), and more recently Kotilainen et al . () and Häusler et al . () looked at long‐term foraminiferal changes in sediment cores.…”

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)

“…Zillén et al, 2008, and references therein; Kotilainen et al, 2014), there are no continuous records from the Baltic Sea and its connections to the Kattegat (Little Belt, Great Belt, and Öresund) enabling multi-proxy studies in high temporal resolution for the entire Holocene (Andrén et al, 2015a). In particular, the Holocene history of the Little Belt has not been the focus of research (Bennike and Jensen, 2011).…”