Abstract
Climate change has a strong impact on ecosystem health, particularly in marginal seas such as the Baltic, for example causing the spreading of anoxic areas (oxygen-free areas, the so-called dead zones) through strong feedbacks. Marked ecosystem changes in the Baltic Sea have been recorded in the sedimentary archive, but the reasons are not fully understood. Here we report an integrated study of high-resolution sediment records (past 1,000 years) in combination with an ecosystem modelling approach, providing new insights into the functioning of the Baltic Sea ecosystem under natural and human-influenced climatic changes. Between the Little Ice Age and the Modern Warm Period the surface water temperatures reconstructed using TEX 86 palaeothermometry increased by ∼2 °C. Simultaneously, the anoxic areas in the Baltic Sea began to expand significantly as evident from the accumulation of laminated sediments. Ecosystem model simulations support our findings of widespread oxic areas during the Little Ice Age. Backed up by the modelling results that take into account anthropogenic-influenced nutrient load scenarios, our results provide evidence that surface temperature changes strongly influence deepwater oxygenation. This highlights the risk of a continued spreading of anoxic areas during scenarios of continued climate warming in the future.
| Original language | English |
|---|---|
| Journal | Nature Climate Change |
| Volume | 2 |
| Pages (from-to) | 871-874 |
| Number of pages | 4 |
| ISSN | 1758-678X |
| Publication status | Published - Dec 2012 |
