Diagrammatic explanation of the influence of variability in sea ice extent on δ18Oequil. at the bivalve site. The relationship between the GIN Seas water-masses and the bivalve site under the three different approximate climatological sea ice states proposed for the three intervals highlighted in Fig. 2, and the implications for δ18Oequil. variability in response to multidecadal (i.e. small-scale) sea ice variability around these three climatological states.