Environmental control of the dominant phytoplankton in the Cariaco basin: a hierarchical Bayesian approach

Abstract

We develop a hierarchical Bayesian model linking the abundance of individual phytoplankton species with over a decade (1995–2011) of environmental data from the Cariaco Ocean Time Series Program in the Cariaco Basin, Venezuela, to characterize how phytoplankton respond to environmental forcing. Temperature, salinity, irradiance, and macronutrient concentrations account for 39% of the variation in log cell abundance across 67 species. Individual phytoplankton taxa varied widely in their response to these environmental variables. A principal component analysis of the environmental response profiles clearly distinguishes the responses of diatoms and dinoflagellates to environmental forcing. Phytoplankton abundance primarily varied with temperature, pH, and irradiance, with salinity and macronutrient concentrations acting as secondary drivers. In the aggregate, our results demonstrate that environmental changes, whether short-term or a result of climate change, should be expected to have dramatic consequences on the taxonomic composition of phytoplankton communities.

Keywords:

• Bayesian analysis
• bottom-up control
• community structure
• environmental forcing
• phytoplankton abundance

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

CMM was supported by an Ace-Net post-doctoral fellowship and the Marjorie Young Bell faculty fund. AJI and ZVF were supported by NSERC Canada. The CARIACO Ocean Time Series Programme has been made possible through the support of the Venezuelan Fondo Nacional de Ciencia, Tecnología e Innovacion (FONACIT) and the US National Science Foundation (NSF, grants OCE-0326268, OCE-0752139, and OCE-0963028 to FMK). We are grateful to the scientific, technical and administrative staff of the Fundación La Salle de Ciencias Naturales de Venezuela, in particular Ramón Varela and Yrene Astor, for their able support at sea and in leading the CARIACO programme. We are particularly indebted to the crew and captain of the R/V Hno Gines for their expert support at sea.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark