Epibenthic foraminifera stable isotope and planktic foraminifera Ba/Ca data of sediment core MD03-2664

Deep ocean circulation has been considered relatively stable during interglacial periods, yet little is known about its behavior on submillennial time scales. Using a subcentennially resolved epibenthic foraminiferal d13C record we show that North Atlantic Deep Water (NADW) influence was strong at the onset of the last interglacial period and then interrupted by several prominent, centennial-scale reductions. These NADW transients occurred during periods of increased ice rafting and southward expansions of polar water influence, suggesting that a buoyancy threshold for convective instability was triggered by freshwater and circum-Arctic cryosphere changes. The deep Atlantic chemical changes were similar in magnitude to those associated with glaciations, implying that the canonical view of a relatively stable interglacial circulation may not hold for conditions warmer/fresher than at present.深海环流在间冰期（interglacial periods）被认为相对稳定，但学界对其在亚千年时间尺度上的演化行为尚缺乏深入认知。本研究依托一项亚百年分辨率的底栖有孔虫碳同位素（δ¹³C）记录，发现末次间冰期初期北大西洋深层水（North Atlantic Deep Water, NADW）的影响显著增强，随后被多次显著的百年尺度减弱事件打断。这些北大西洋深层水的瞬变过程发生在冰筏沉积增多、极地水团影响向南扩张的时期，表明淡水输入与环北极冰冻圈变化触发了对流不稳定的浮力阈值。大西洋深层的化学变化幅度与冰期相关变化相当，这意味着关于间冰期环流相对稳定的经典认知，在比现今更暖、水体更淡的环境条件下可能并不成立。