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Global surface ocean phytoplankton community structure determined from co-variability in phytoplankton pigment concentrations
  • Sasha Kramer,
  • David Siegel
Sasha Kramer

Corresponding Author:[email protected]

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David Siegel
University of California Santa Barbara
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Abstract

High performance liquid chromatography (HPLC) remains one of the most widely applied methods currently available for estimation of phytoplankton taxonomy from ocean samples. This method measures the concentrations of phytoplankton pigments, some of which are useful chemotaxonomic markers that can be used to diagnose the relative abundance of phytoplankton groups. Here, we use HPLC phytoplankton pigment concentrations measured on surface water samples from 38 field surveys for a total of over 3,000 distinct samples that cover every major ocean basin and represent a wide range of ecological regimes. The data compilation has been quality controlled to remove measurements below pigment detection limits and outliers from the linear regression of total chlorophyll-a concentration with total accessory pigment concentrations and only samples from labs that have participated in round-robin quality assurance experiments (e.g. NASA SeaHARRE) have been included. We assess the environmental and spatial drivers controlling the global distribution and co-variability of individual phytoplankton pigments. Preliminary results of hierarchical clustering show strong differentiation in phytoplankton pigments following known relationships between phytoplankton size class and relative pigment concentration, partitioning their contributions by micro-, nano-, and pico-phytoplankton size classes. However, the exact clusters relationships change when the data are divided by ocean basin or latitude. We also use statistical techniques, including EOFs and network-based exploration, to examine the associations between groups of pigments over a range of environmental conditions on local to global scales and diagnose the main controls on these associations.