Haplo-diplontic life cycle expands coccolithophore niche

Joost C De Vries*, Fanny M Monteiro, Glen Wheeler, Alex Poulton, Jelena Godrijan, Federica Cerino, Elisa Malinverno, Gerald Langer, Colin Brownlee

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

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Abstract

Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo-diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases and potentially expands coccolithophore niche volume. Research has, however, to date largely overlooked the life cycle of coccolithophores and has instead focused on the diploid life cycle phase of coccolithophores. Through the synthesis and analysis of global scanning electron microscopy (SEM) coccolithophore abundance data (n = 2534), we find that calcified haploid coccolithophores generally constitute a minor component of the total coccolithophore abundance (≈ 2 %-15 % depending on
season). However, using case studies in the Atlantic Ocean and Mediterranean Sea, we show that, depending on environmental conditions, calcifying haploid coccolithophores
can be significant contributors to the coccolithophore standing stock (up to ≈ 30 %). Furthermore, using hypervolumes to quantify the niche of coccolithophores, we illustrate that the haploid and diploid life cycle phases inhabit contrasting niches and that on average this allows coccolithophores to expand their niche by ≈ 18.8 %, with a range of 3 %–76 % for individual species.

Our results highlight that future coccolithophore research should consider both life cycle stages, as omission of the haploid life cycle phase in current research limits our understanding of coccolithophore ecology. Our results furthermore suggest a different response to nutrient limitation and stratification, which may be of relevance for further climate scenarios.

Our compilation highlights the spatial and temporal sparsity of SEM measurements and the need for new molecular techniques to identify uncalcified haploid coccolithophores.
Our work also emphasizes the need for further work on the carbonate chemistry niche of the coccolithophore life cycle.
Original languageEnglish
Pages (from-to)1161–1184
Number of pages24
JournalBiogeosciences
Volume18
Issue number3
DOIs
Publication statusPublished - 16 Feb 2021

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