Coccolithophore ecology
: with a special focus on their life cycle and standing stocks

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)

Abstract

Coccolithophores play an important role in regulating the climate through their influence on the organic and inorganic carbon pumps. Coccolithophores’ influence on the ocean carbon pumps depends on their ecology, our understanding of which is currently limited to a few species. My thesis thus aims at improving our knowledge of coccolithophore ecology by investigating the nature and function of the coccolithophore life cycle (haploid versus diploid phases) and quantifying the global standing stocks of the most common coccolithophore species. I used a trait-based framework and a multidisciplinary approach that combines statistical analysis, lab experiments, machine learning and numerical modelling.

Using statistical analysis, I quantify the niche occupied by haploid and diploid coccolithophores, showing that the coccolithophore life cycle expands coccolithophore niche by ≈ 18%. Additionally, using lab experiments and numerical modelling, I demonstrate that a trade-off between nutrient storage and maximum growth is a critical bottom-up control of Coccolithus pelagicus life stages’ distribution. Finally, using machine learning approaches, I estimate that two genera account for the majority of coccolithophore’s global organic carbon standing stock and that mid-to-low latitude regions contribute similarly to high-latitude regions.

This thesis provides novel insights into the ecology of the coccolithophore life cycle and the species that dominate coccolithophore biomass, and furthermore lays the groundwork for future coccolithophore research by identifying some of the key coccolithophore species and traits. My thesis also successfully applied novel multidisciplinary approaches leading the way to improve the ecology of marine plankton in general.
Date of Award21 Mar 2023
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorFanny M Monteiro (Supervisor), Glen Wheeler (Supervisor), Colin Brownlee (Supervisor) & Oliver D Andrews (Supervisor)

Keywords

  • coccolithophores
  • ecology
  • standing stocks
  • haplo-diplontic
  • SDM
  • Machine Learning
  • inorganic carbon
  • Coccolithus pelagicus
  • Coccolithus braarudii

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