Culture experiments were used to assess the applicability of Emiliania huxleyi coccolith morphology as a palaeo–sea-surface salinity (SSS) proxy. Coccolith morphology was dependent on salinity over a range reflecting present day marine...
moreCulture experiments were used to assess the applicability of Emiliania huxleyi coccolith morphology as a
palaeo–sea-surface salinity (SSS) proxy. Coccolith morphology was dependent on salinity over a range reflecting
present day marine conditions; both coccolith size and the number of coccolith elements increased linearly with
increasing salinity. Using regression analysis, the effect of salinity on coccolith morphology was compared to
those previously observed in sediment core-top and plankton data. No significant differences were found between
the slopes of these data, suggesting that salinity is the primary control on E. huxleyi coccolith size and element
number in the ocean. However, the intercepts of the culture data were significantly higher. A combination of
experimental and literature analysis indicated that temperature and nutrients were unlikely to be the causes of this
discrepancy. Literature analysis also highlighted that coccolith size data from marginal environments displayed
different intercepts to those from the open-ocean data. This suggests that discrete morphotypes exist in these
marginal locations. We, therefore, recommend that the original E. huxleyi coccolith morphology palaeo-SSS
transfer function requires further evaluation before being routinely applied.
