Potential and limitation of combining terrestrial and marine growth records from Iceland

Sampling sites of the dendro and sclero data (circles and triangles), with colors referring to their correlation coefficients (r) against mean monthly air temperature (Tmean) and sea surface temperature (SST), respectively. White and green areas on Iceland represent ice and woodland cover (Traustason and Snorrason, 2008). Values at each site location indicate the month of highest correlation (e.g. '6' = June, '6:7' = June-July, '− 6' = June of the previous year). Values in square brackets at the four cardinal points are correlation coefficients (r) between Tmean and SST, at the pairings of Iceland's four geographical sectors, NW-SW, SW-SE, SE-NE, NE-NW. The first, left value refers to the seasonal length of shell growth (February-September), whereas the second, right value indicates the seasonal length of tree growth (June-August). Light blue shadings in the inset depict the natural distribution of Arctica islandica (modified after Dahlgren et al., 2000), with red and blue arrows representing warm and cold ocean currents, respectively.267