Evaluating merged Zeu products in the Southern Ocean for application towards an optimised fluorescence quenching correction method.

It is common practice to infer the size structure of phytoplankton communities in situ from either diagnostic pigments, estimated by High Performance Liquid
Chromatography (HPLC), or through size-fractionated filtration (SFF). In this
presentation, the three-component model of Brewin et al. (2010) was fitted to
coincident data from HPLC and from SFF collected along Atlantic Meridional Transect cruises. Both HPLC and SFF data supported the conceptual framework of the threecomponent model, but the fitted model parameters differed for the two datasets. The three-component model was extended to a multi-component model of size structure using observed relationships between model parameters and assuming that the asymptotic concentration that can be reached by cells increased linearly with increase in the upper bound on the cell size. The multi-component model was verified using independent SFF data for a variety of size-fractions along the AMT transect and found to perform well (0.628 < r < 0.989) lending support for the underlying assumptions. An advantage of the multi-component model over the three-component model is that, for the same number of parameters, it can be applied to any size range in a continuous fashion.