Fig. 3: %C37:4 showing significant positive correlation with annual mean sea ice concentration and negative correlation with sea surface salinity.
From: Group 2i Isochrysidales produce characteristic alkenones reflecting sea ice distribution
a Linear regression between water filter POM %C37:4 compiled from previous studies15,16 and mean sea ice concentration 12 months prior to sample collection (n = 40 independent samples). b Linear regression between water filter POM %C37:4 and measured SSS during collection15,16 (n = 40 independent samples). c Linear regression between surface sediment %C37:4 and 1980–2010 annual mean sea ice concentration (n = 42 independent samples). d Linear regression between surface sediment %C37:4 and 1980–2010 annual mean SSS85 (n = 42 independent samples). Surface sediment samples from Baltic Sea are not included in the regressions in c and d. Sea ice concentrations were obtained from NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 3, with a spatial resolution of 25 km × 25 km84 (https://doi.org/10.7265/N59P2ZTG). The dashed lines denote 95% confidence interval for the regression.
