01944nas a2200157   4500000000100000008004100001100002100042700002100063700001600084245009300100856004200193300002200235490000800257520150700265022001401772       2008                            d1 aDavid Thornalley1 aHarry Elderfield1 aNick Mccave00aHolocene oscillations in temperature and salinity of the surface subpolar North Atlantic  uhttp://dx.doi.org/10.1038/nature07717  a711\textendash7140 v4573 a<p>The Atlantic meridional overturning circulation (AMOC) transports warm salty surface waters to high latitudes, where they cool, sink and return southwards at depth. Through its attendant meridional heat transport, the AMOC helps maintain a warm northwestern European climate, and acts as a control on the global climate. Past climate fluctuations during the Holocene epoch (approx 11,700 years ago to the present) have been linked with changes in North Atlantic Ocean circulation (1, 2). The behaviour of the surface flowing salty water that helped drive overturning during past climatic changes is, however, not well known. Here we investigate the temperature and salinity changes of a substantial surface inflow to a region of deep-water formation throughout the Holocene. We find that the inflow has undergone millennial-scale variations in temperature and salinity (approx 3.5 \textdegreeC and approx 1.5 practical salinity units, respectively) most probably controlled by subpolar gyre dynamics. The temperature and salinity variations correlate with previously reported periods of rapid climate change3. The inflow becomes more saline during enhanced freshwater flux to the subpolar North Atlantic. Model studies predict a weakening of AMOC in response to enhanced Arctic freshwater fluxes4, although the inflow can compensate on decadal timescales by becoming more saline. Our data suggest that such a negative feedback mechanism may have operated during past intervals of climate change.</p>  a0028-0836