Delayed Western Gotland Basin (Baltic Sea) ventilation in response to the onset of a Mid-Holocene climate oscillation

The marine-terrestrial Baltic ecosystem is sensitive to a range of environmental forcing and thresholds. Multi-archive investigations of its evolution require a precise synchronization of the considered archives. Here, we apply globally common cosmogenic radionuclide production rate variations to synchronize Be-10 records from brackish Western Gotland Basin (Baltic Sea) and terrestrial lake Tiefer See (NE Germany) sediments to the atmospheric C-14 time-scale and investigate phase-relationships in proxy responses in the southern Baltic realm associated with the onset of a centennial Mid- Holocene climate oscillation similar to 5800 a BP. Based on paired molybdenum and titanium records, we identify a 98 +/- 81-year delay in Western Gotland Basin ventilation, compared to the terrestrial response at the onset of the recorded MidHolocene climate oscillation. Most plausible mechanism for this delay is strengthened stratification in response to enhanced freshwater input during the first decades of the oscillation. (C) 2021 Elsevier Ltd. All rights reserved.