Detection of phagotrophy in the marine phytoplankton group of the coccolithophores (calcihaptophycidae, haptophyta) during Nutrient-replete and Phosphate-limited growth

TitleDetection of phagotrophy in the marine phytoplankton group of the coccolithophores (calcihaptophycidae, haptophyta) during Nutrient-replete and Phosphate-limited growth
Publication TypeJournal Article
Year of Publication2020
AuthorsAvrahami Y, Frada MJ
Secondary AuthorsMock T.
JournalJournal of Phycology
Paginationjpy.12997
Date Publishedapr
ISSN0022-3646
Keywordsbacterivory, coccolithophores, life cycle, mixotrophy, phytoplankton, RCC1130, RCC1131, RCC1178, RCC1216, rcc1217, RCC3779
Abstract

Mixotrophic algae that combine photoautotrophy with phagotrophy in a single cell are prevalent in marine ecosystems. Here, we assessed the ability of food ingestion in coccolithophores, an important group of calcifying haptophytes inhabiting the oceans. We tested four species from different coccolithophore lineages (Emiliania huxleyi, Calcidiscus leptoporus, Coccolithus braarudii, and Calyptrosphaera sphaeroidea). For both E. huxleyi and C. leptoporus we included different life phases (haploid and diploid). For C. braarudii we only tested diploid heterococcolithophore cells, while for C. sphaeroidea we only tested haploid holococcolithophore cells. Phagotrophy was assessed using fluorescently labeled bacteria (FLB) as model prey item, under nutrient-replete and phosphate-limited conditions. We detected by microscopy ingestion of FLB by all species, except the diploid C. braarudii strain. However, a previous study detected ingestion by haploid cells of C. braarudii. These overall results indicate that mixotrophy and the ability to ingest prey is widespread in coccolithophores. Yet, in all tested species the ingestion of FLB was low (¡1% of the population contained prey at all time points over 2 days), namely for E. huxleyi and the diploid cells from C. leptoporus where detection of ingestion was sporadic. Moreover, no clear differences were detected between life phases in E. huxleyi and C. leptoporus under equal circumstances, or between replete and limited growth conditions.

URLhttps://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.12997
DOI10.1111/jpy.12997