The fast‑acting “pulse” of Heinrich Stadial 3 in a mid‑latitude boreal ecosystem

• Published in: Scientific Reports
• Main Authors: Federica Badino, Roberta Pini, Paolo Bertuletti, Cesare Ravazzi, Barbara Delmonte, Giovanni Monegato, Paula Reimer, Francesca Vallé, Simona Arrighi, Eugenio Bortolini, Carla Figus, Federico Lugli, Valter Maggi, Giulia Marciani, Davide Margaritora, Gregorio Oxilia, Matteo Romandini, Sara Silvestrini, Stefano Benazzi
• Other Authors: Federica Badino, Roberta Pini, Paolo Bertuletti, Cesare Ravazzi, Barbara Delmonte, Giovanni Monegato, Paula Reimer, Francesca Vallé, Simona Arrighi, Eugenio Bortolini, Carla Figus,, Federico Lugli, Valter Maggi, Giulia Marciani, Davide Margaritora, Gregorio Oxilia, Matteo Romandini, Sara Silvestrini, Stefano Benazzi
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: HeinrichEvents; palaeoecology; palaeoclimatology; pollen; palaeofires; North Atlantic
• Online Access: http://hdl.handle.net/11585/775584; https://doi.org/10.1038/s41598-020-74905-0; https://www.nature.com/articles/s41598-020-74905-0

A 3800 year-long radiocarbon-dated and highly-resolved palaeoecological record from Lake Fimon (N-Italy) served to investigate the effects of potential teleconnections between North Atlantic and mid-to-low latitudes at the transition from Marine Isotope Stage (MIS) 3 to 2. Boreal ecosystems documented in the Fimon record reacted in a sensitive way to millennial and sub-millennial scale Northern Hemisphere atmospheric circulation patterns. The high median time-resolution of 58 years allows the identification of five abrupt event-boundaries (i.e., main forest expansion and decline excursions) synchronous with the sharp stadial/interstadial (GS/GI) transitions within dating uncertainties. During Heinrich Stadial 3 (HS 3) we reconstruct more open and dry conditions, compared to the other GS, with a dominant regional scale fire signal. Linkages between local fires and climate-driven fuel changes resulted in high-magnitude fire peaks close to GI/GS boundaries, even exacerbated by local peatland conditions. Finally, palaeoecological data from the HS 3 interval unveiled an internal variability suggesting a peak between 30,425 and 29,772 cal BP (2σ error) which matches more depleted δ18O values in alpine speleothems. We hypothesise that this signal, broadly resembling that of other mid-latitudes proxies, may be attributed to the southward shift of the Northern Hemisphere storm tracks and the associated delayed iceberg discharge events as documented during other HS.