The paradox of the plankton: species competition and nutrient feedback sustain phytoplankton diversity

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 490:107-119 (2013) - DOI: https://doi.org/10.3354/meps10452 The paradox of the plankton: species competition and nutrient feedback sustain phytoplankton diversity Kasia Kenitz1, Richard G. Williams1,*, Jonathan Sharples1,2, Özgür Selsil3 , Vadim N. Biktashev3 1School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK 2National Oceanography Centre, Liverpool, Liverpool L3 5DA, UK 3School of Mathematical Sciences, University of Liverpool, Liverpool L69 7ZL, UK *Corresponding author. Email: ric@liverpool.ac.uk ABSTRACT: The diversity of phytoplankton species and their relationship to nutrient resources are examined using a coupled phytoplankton and nutrient model for a well-mixed box. The phytoplankton community either reaches a competitive exclusion state, where there is an optimal competitor, or the abundance of each phytoplankton species continually varies in the form of repeating oscillations or irregular chaotic changes. Oscillatory and chaotic solutions make up over half of the model solutions based upon sets of 1000 separate model integrations spanning large, moderate or small random changes in the half-saturation coefficient, Kji. The oscillatory or chaotic states allow a greater number of phytoplankton species to be sustained, even for their number to exceed the number of resources after additional species have been injected into the environment. The chaotic response, however, only occurs for particular model choices: when there is an explicit feedback between nutrient supply and ambient nutrient concentration, and when there are physiological differences among species, including cell quota and Kji. In relation to the surface ocean, the nutrient feedback can be viewed as mimicking the diffusive nutrient supply from the nutricline. Inter-species competition might then be important in generating chaos when this diffusive transfer is important, but less likely to be significant when other transport processes sustain surface nutrient concentrations. KEY WORDS: Plankton paradox · Coexistence · Chaos · Competitive exclusion · Phytoplankton communities Full text in pdf format Supplementary material PreviousNextCite this article as: Kenitz K, Williams RG, Sharples J, Selsil Ö, Biktashev VN (2013) The paradox of the plankton: species competition and nutrient feedback sustain phytoplankton diversity. Mar Ecol Prog Ser 490:107-119. https://doi.org/10.3354/meps10452 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 490. Online publication date: September 17, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.