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Publication Title

Limnology and Oceanography








The California Current System is a diatom-dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental gradients and through a lens of community succession to expand our understanding of biophysical interactions in California Current System cyclonic eddies. Diatom communities within each eddy were different from non-eddy communities and varied in concert with salinity and dissolved iron (Fe) concentrations. The younger, nearshore eddy displayed higher macronutrient and dissolved Fe concentrations, had higher values for diatom Shannon diversity and evenness, and had nutrient ratios indicative of either eventual silicic acid (Si) or Fe limitation or possibly co-limitation. The older, offshore eddy displayed low macronutrient and dissolved Fe concentrations, was likely nitrate-limited, and had lower diatom Shannon diversity and evenness indices. Sequences from the genus Rhizosolenia, some of which form vertically migrating mats to bypass nitrate limitation, dominated in the older eddy. This is of potential significance as the prevalence of Rhizosolenia mats could impact estimates of carbon cycling and export in the wider California coastal area.


© 2022 The Authors.

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Data Availability

Article states: "The data repository for this manuscript is hosted at the Biological & Chemical Oceanography Data Management Office ( Sequencing data can be found in the NCBI Sequence Read Archive (Bioproject accession # PRJNA743307): Access to the complete dataset from the underway system for the MV1405 cruise is available via the Rolling Deck Repository:"

Information regarding material archived at the Rolling Deck Repository for the MV1405 cruise can be found at:

Original Publication Citation

Abdala, Z. M., Clayton, S., Einarsson, S. V., Powell, K., Till, C. P., Coale, T. H., & Chappell, P. D. (2022). Examining ecological succession of diatoms in California Current System cyclonic mesoscale eddies. Limnology & Oceanography, 67(11), 2586-2602.


0000-0002-9666-8405 (Abdala), 0000-0001-7473-4873 (Clayton), 0000-0003-4057-5266 (Einarsson), 0000-0001-5212-6228 (Chappell)


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