Holocene wet shifts in NW European bogs: evidence for the roles of external forcing and internal feedback from a high‐resolution study of peat properties, plant macrofossils and testate amoebae

ABSTRACT Two conspicuous wet shifts in the peat stratigraphy of Store Mosse southern Sweden, associated with bog‐wide changes vegetation and degree decomposition, were analysed at high resolution. The bog‐surface wetness (BSW) proxy data (organic matter bulk density, C/N ratio, plant macrofossils testate amoebae) highlight importance interactions between composition, microtopography show that bog system operated consistently during two (dated to c . 2700 1000 cal a bp ) despite different internal external conditions. A sensitive bog‐system state, degraded well‐decomposed surface low hydrological conductivity developed sustained dry conditions, probably contributed large BSW amplitudes registered. Comparable systems are expected operate same way, regionally sensitivity response atmospheric circulation may partly explain synchronous registration shifts. attributed solar volcanic forcing, respectively, similar magnitude registered other NW European bogs likely also have been externally forced.