Gephyrocapsa huxleyi (Emiliania huxleyi) as a model system for coccolithophore biology

Abstract

Coccolithophores are the most abundant calcifying organisms in modern oceans and are important primary producers in many marine ecosystems. Their ability to generate a cellular covering of calcium carbonate plates (coccoliths) plays a major role in marine biogeochemistry and the global carbon cycle. Coccolithophores also play an important role in sulfur cycling through the production of the climate‐active gas dimethyl sulfide. The primary model organism for coccolithophore research is Emiliania huxleyi, now named Gephyrocapsa huxleyi. G. huxleyi has a cosmopolitan distribution, occupying coastal and oceanic environments across the globe, and is the most abundant coccolithophore in modern oceans. Research in G. huxleyi has identified many aspects of coccolithophore biology, from cell biology to ecological interactions. In this perspective, we summarize the key advances made using G. huxleyi and examine the emerging tools for research in this model organism. We discuss the key steps that need to be taken by the research community to advance G. huxleyi as a model organism and the suitability of other species as models for specific aspects of coccolithophore biology.

Intraspecific diversity in thermal performance determines phytoplankton ecological niche

“…Moreover, intraspecific diversity within G . huxleyi is well-described, including in calcite elemental composition, growth rate, C:N ratio, and thermal response (43, 45–48). Distinct G. huxleyi isolates have unique thermal reaction norms (36, 49), and strain diversity can shift thermal reaction norms in ecologically significant ways (50).…”

“…To directly interrogate the effect of diversity on thermal response, we used Gephyrocapsa (formerly Emiliania) huxleyi as a model system. G. huxleyi is frequently grown in the laboratory as a model phytoplankter due to its global distribution and ease of culturing (43) as well as its developed molecular resources (44). Moreover, intraspecific diversity within G. huxleyi is well-described, including in calcite elemental composition, growth rate, C:N ratio, and thermal response (43,(45)(46)(47)(48).…”

“…G. huxleyi is frequently grown in the laboratory as a model phytoplankter due to its global distribution and ease of culturing (43) as well as its developed molecular resources (44). Moreover, intraspecific diversity within G. huxleyi is well-described, including in calcite elemental composition, growth rate, C:N ratio, and thermal response (43,(45)(46)(47)(48). Distinct G. huxleyi isolates have unique thermal reaction norms (36,49), and strain diversity can shift thermal reaction norms in ecologically significant ways (50).…”

Phagocytosis in Marine Coccolithophore Gephyrocapsa huxleyi: Comparison between Calcified and Non-Calcified Strains

“…Coccolithophore blooms greatly increase both POC (particle organic carbon) and PIC (particle inorganic carbon) export to the deep ocean [13], and the deposited coccoliths eventually contribute to the formation of calcareous ooze in deep-sea sediments. The most abundant and widely distributed coccolithophore species in the ocean is Gephyrocapsa huxleyi, formerly known as Emiliania huxleyi [14][15][16], which has been widely used as a model organism to study biogenic calcification and in the marine global carbon cycle [16,17].…”

Technical note: A comparison of methods for estimating coccolith mass

“…The coccolithophore species Emiliania huxleyi, more recently based on genetic arguments also referred to as Gephyrocapsa huxleyi (Bendif et al, 2023;Wheeler et al, 2023), is amongst the numerically most abundant and geographically distributed representatives of this functional group in the modern ocean, being an important model species for physiological and biomineralization studies (e.g., Henderiks and Pagani, 2008;Triantaphyllou et al, 2010;Poulton et al, 2011;Müller et al, 2012;Hoffmann et al, 2015;Faucher et al, 2020). In the Southern Ocean, the most dominant ecotypes of E. huxleyi are A and BC with distinct differences in their cellular physiology and morphological coccolith structure.…”