@article {bendif_rapid_2023,
	title = {Rapid diversification underlying the global dominance of a cosmopolitan phytoplankton},
	journal = {The ISME Journal},
	year = {2023},
	note = {Publisher: Nature Publishing Group},
	pages = {1{\textendash}11},
	abstract = {Marine phytoplankton play important roles in the global ecosystem, with a limited number of cosmopolitan keystone species driving their biomass. Recent studies have revealed that many of these phytoplankton are complexes composed of sibling species, but little is known about the evolutionary processes underlying their formation. Gephyrocapsa huxleyi, a widely distributed and abundant unicellular marine planktonic algae, produces calcified scales (coccoliths), thereby significantly affects global biogeochemical cycles via sequestration of inorganic carbon. This species is composed of morphotypes defined by differing degrees of coccolith calcification, the evolutionary ecology of which remains unclear. Here, we report an integrated morphological, ecological and genomic survey across globally distributed G. huxleyi strains to reconstruct evolutionary relationships between morphotypes in relation to their habitats. While G. huxleyi has been considered a single cosmopolitan species, our analyses demonstrate that it has evolved to comprise at least three distinct species, which led us to formally revise the taxonomy of the G. huxleyi complex. Moreover, the first speciation event occurred before the onset of the last interglacial period (\textasciitilde140 ka), while the second followed during this interglacial. Then, further rapid diversifications occurred during the most recent ice-sheet expansion of the last glacial period and established morphotypes as dominant populations across environmental clines. These results suggest that glacial-cycle dynamics contributed to the isolation of ocean basins and the segregations of oceans fronts as extrinsic drivers of micro-evolutionary radiations in extant marine phytoplankton.},
	keywords = {Microbial biooceanography, phylogenomics, population genetics, rcc1212, RCC1216, rcc1220, RCC1239, RCC1240, RCC1242, RCC1245, rcc1252, RCC1253, RCC1266, RCC1304, rcc1731, RCC1754, RCC1813, RCC1823, rcc1824, RCC1830, RCC1838, RCC1840, RCC1853, RCC1856, RCC3746, RCC4027, RCC4028, RCC4030, RCC5134, RCC5137, RCC5141, RCC6381, RCC6421, RCC6427, RCC6566, RCC6660, RCC6666, RCC911, RCC963},
	issn = {1751-7370},
	doi = {10.1038/s41396-023-01365-5},
	url = {https://www.nature.com/articles/s41396-023-01365-5},
	author = {Bendif, El Mahdi and Probert, Ian and Archontikis, Odysseas A. and Young, Jeremy R. and Beaufort, Luc and Rickaby, Rosalind E. and Filatov, Dmitry}
}
@article {xie_disentangling_2021,
	title = {Disentangling the Effects of Ocean Carbonation and Acidification on Elemental Contents and Macromolecules of the Coccolithophore Emiliania huxleyi},
	journal = {Frontiers in Microbiology},
	volume = {12},
	year = {2021},
	pages = {3188},
	abstract = {Elemental contents change with shifts in macromolecular composition of marine phytoplankton. Recent studies focus on the responses of elemental contents of coccolithophores, a major calcifying phytoplankton group, to changing carbonate chemistry, caused by the dissolution of anthropogenically derived CO2 into the surface ocean. However, the effects of changing carbonate chemistry on biomacromolecules, such as protein and carbohydrate of coccolithophores, are less documented. Here, we disentangled the effects of elevated dissolved inorganic carbon (DIC) concentration (900 to 4,930μmolkg-1) and reduced pH value (8.04 to 7.70) on physiological rates, elemental contents, and macromolecules of the coccolithophore Emiliania huxleyi. Compared to present DIC concentration and pH value, combinations of high DIC concentration and low pH value (ocean acidification) significantly increased pigments content, particulate organic carbon (POC), and carbohydrate content and had less impact on growth rate, maximal relative electron transport rate (rETRmax), particulate organic nitrogen (PON), and protein content. In high pH treatments, elevated DIC concentration significantly increased growth rate, pigments content, rETRmax, POC, particulate inorganic carbon (PIC), protein, and carbohydrate contents. In low pH treatments, the extents of the increase in growth rate, pigments and carbohydrate content were reduced. Compared to high pH value, under low DIC concentration, low pH value significantly increased POC and PON contents and showed less impact on protein and carbohydrate contents; however, under high DIC concentration, low pH value significantly reduced POC, PON, protein, and carbohydrate contents. These results showed that reduced pH counteracted the positive effects of elevated DIC concentration on growth rate, rETRmax, POC, PON, carbohydrate, and protein contents. Elevated DIC concentration and reduced pH acted synergistically to increase the contribution of carbohydrate{\textendash}carbon to POC, and antagonistically to affect the contribution of protein{\textendash}nitrogen to PON, which further shifted the carbon/nitrogen ratio of E. huxleyi.},
	keywords = {rcc, RCC1266},
	issn = {1664-302X},
	doi = {10.3389/fmicb.2021.737454},
	url = {https://www.frontiersin.org/article/10.3389/fmicb.2021.737454},
	author = {Xie, Emei and Xu, Kui and Li, Zhengke and Li, Wei and Yi, Xiangqi and Li, Hongzhou and Han, Yonghe and Zhang, Hong and Zhang, Yong}
}
@article {zhang_growth-dependent_2021,
	title = {Growth-dependent changes in elemental stoichiometry and macromolecular allocation in the coccolithophore Emiliania huxleyi under different environmental conditions},
	journal = {Limnology and Oceanography},
	volume = {66},
	number = {8},
	year = {2021},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11854},
	pages = {2999{\textendash}3009},
	abstract = {The growth rate hypothesis (GRH) posits an increase in ribosomal ribonucleic acid (RNA) content, and therefore cellular phosphorus (P), with increasing growth rate. There is evidence that the GRH may not apply to phytoplankton under all conditions. Here, we experimentally controlled four conditions (light, temperature, pH, and CO2) to alter the growth rate of Emiliania huxleyi, a biogeochemically important coccolithophorid, and monitored changes in RNA, protein, and carbohydrate content. We show that an increase in growth rate caused by increasing light, pH, and CO2 resulted in increased RNA per unit of organic carbon (RNA : POC), but that increasing temperature, leading to increase of growth rate, resulted in a decrease in RNA : POC. Protein per unit of organic carbon (protein : POC) increased in our increased temperature, pH, and CO2 treatments that increased growth rate, but there was little change in protein : POC in our light treatment despite it inducing the same increase in growth rate. Carbohydrate per unit of organic carbon (Carbohydrate : POC) increased with growth rate under increased light and CO2 but did not vary significantly in the temperature or pH treatments. These results indicate that physiological acclimation to specific environmental conditions can lead to contrasting patterns in RNA, protein, and carbohydrate composition and therefore contrasting changes in carbon : nitrogen : phosphorus ratios with growth rate in E. huxleyi.},
	keywords = {rcc, RCC1266},
	issn = {1939-5590},
	doi = {10.1002/lno.11854},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/lno.11854},
	author = {Zhang, Yong and Li, Zhengke and Schulz, Kai G. and Hu, Yingyu and Irwin, Andrew J. and Finkel, Zoe V.}
}
