@article {chauhan_size-dependent_2024,
	title = {Size-dependent dynamics of the internal carbon pool drive isotopic vital effects in calcifying phytoplankton},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {373},
	year = {2024},
	pages = {35{\textendash}51},
	abstract = {Isotopic offsets in biogenic calcite from equilibrium values can provide unique insights into the physiology and mechanisms of carbon regulation in calcifying phytoplankton. This study examines the impact of varying CO2 (controlled via pH) on five coccolithophore species chosen for varied cell sizes, physiology, and calcification. The study investigates isotopic offsets in coccolith calcite and organic matter, in relation to carbon demand and supply ({\textmu}/CO2). Species-specific CO2 and/or pH optima for growth ({\textmu}opt) were derived from variations in growth rates with varying CO2 concentrations. Growth rates for all species declined with rising CO2 (decreasing pH) due to H+-driven inhibition. C. braarudii and C. leptoporus exhibited {\textmu}opt at high CO2 concentrations (suggesting high carbon-demand) and limited growth under low CO2 (high pH) suggesting carbon limitation. Under low CO2 supply, when growth rates were CO2-limited, both species exhibited coincident isotopic depletion in calcite and organic matter as a consequence of CO2 diffusion into the cell that experienced no equilibration as a result of a highly depleted internal carbon pool. In these two species, isotopic values in calcite remained unaffected by growth rates and CO2 concentration ({\textmu}/CO2) when CO2 was sufficient for optimal growth. G. huxleyi and G. oceanica displayed optima for growth ({\textmu}opt) at low CO2 concentrations and showed no growth limitation under low CO2 (indicating low carbon-demand). Both species experienced depleted (negative) vital effects caused by an excess of CO2 diffusioninto the small internal carbon pool of the cell when diffusive carbon supply outpaced low demand (low {\textmu}/CO2). Enriched (positive) vital effects were observed under low carbon supply and high demand, likely due to increased HCO3{\textendash} uptake and diffusive CO2 loss from the intracellular carbon pooldue to a lower intracellular pH than the seawater pH. C. carterae exhibited a {\textmu}opt at intermediate CO2 concentrations and isotopically equilibrated intracellular carbon pool such that δ13C values in calcite and organic matter suggested a shared carbon pool. This study illustrates that pH and CO2 driven vital effects and fractionation into organic matter indicate the residence time for carbon in the intracellular carbon pool, where the size of the pool is proportional to cell size. Due to the increased buffering afforded by a larger pool, C. leptoporus and C. carterae may have elevated intracellular pH which minimises CO2 leakage, whereas vital effects in G. huxleyi and G. oceanica are caused by CO2 diffusion in or out of their small internal carbon pool with limited buffering capacity owing to its small size.},
	keywords = {Carbon demand and supply, Carbon residence time, coccolithophores, Internal carbon pool, RCC1130, RCC1198, RCC1314, Vital effects},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2024.03.033},
	url = {https://www.sciencedirect.com/science/article/pii/S0016703724001571},
	author = {Chauhan, Nishant and Rickaby, Rosalind E. M.}
}
@booklet {clark_coccolithophorids_2023,
	title = {Coccolithophorids precipitate carbonate in clumped isotope equilibrium with seawater},
	year = {2023},
	month = {nov},
	publisher = {EGUsphere},
	type = {preprint},
	abstract = {Numerous recent studies have tested the clumped isotope (Δ47) thermometer on a variety of biogenic carbonates such as foraminifera and bivalves and showed that all follow a common calibration. While the sample size requirements for a reliable Δ47 measurement have decreased over the years, the availability and preservation of many biogenic carbonates is still 10 limited and/or require substantial time to be extracted from sediments in sufficient amounts. We thus determined the Δ47temperature relationship for coccolith carbonate, which is abundant and often well-preserved in sediments. The carbon and oxygen isotopic compositions of coccolith calcite have limited use in palaeoenvironmental reconstructions due to physiological effects that cause variability in the carbon and oxygen isotopic values. However, the relatively limited data available suggest that clumped isotopes may not be influenced by these effects. We cultured three species of coccolithophores in well15 constrained carbonate system conditions with a CO2(aq) between 5 and 45 μM and temperatures between 6{\textdegree}C and 27{\textdegree}C.},
	keywords = {RCC1130, RCC1303, RCC3370},
	doi = {10.5194/egusphere-2023-2581},
	url = {https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2581/},
	author = {Clark, Alexander J. and Torres-Romero, Ismael and Jaggi, Madalina and Bernasconi, Stefano M. and Stoll, Heather M.}
}
@booklet {barton_novel_2023,
	title = {A novel fluoro-electrochemical technique for classifying diverse marine nanophytoplankton},
	year = {2023},
	month = {apr},
	publisher = {Life Sciences},
	type = {preprint},
	abstract = {<p>To broaden our understanding of pelagic ecosystem responses to environmental change, it is essential that we improve the spatio-temporal resolution of in situ monitoring of phytoplankton communities. A key challenge for existing methods is in classifying and quantifying cells within the nanophytoplankton size range (2-20{\textmu}m). This is particularly difficult when there are similarities in morphology, making visual differentiation difficult for both trained taxonomists and machine learning based approaches. Here we present a rapid fluoro-electrochemical technique for classifying nanophytoplankton, and using a library of 52 diverse strains of nanophytoplankton we assess the accuracy of this technique based on two measurements at the individual level: charge required to reduce per cell chlorophyll a fluorescence by 50\%, and cell radius. We demonstrate a high degree of accuracy overall (\&gt;90\%) in categorising cells belonging to widely recognised key functional groups, however this is reduced when we consider the broader diversity of {\textquotedblleft}nano-phytoflagellates{\textquotedblright}. Notably, we observe that some groups, for example calcifying Isochrysidales, have much greater resilience to electrochemically driven oxidative conditions relative to others of a similar size, making them more easily categorised by the technique. The findings of this study present a promising step forward in advancing our toolkit for monitoring phytoplankton communities. We highlight that, for improved categorisation accuracy, future iterations of the method can be enhanced by measuring additional predictor variables with minimal adjustments to the set-up. In doing so, we foresee this technique being highly applicable, and potentially invaluable, for in situ classification and enumeration of the nanophytoplankton size fraction.</p>
},
	keywords = {RCC1, rcc1084, RCC1130, RCC1150, RCC1178, RCC1185, RCC1198, RCC1216, rcc1217, RCC1242, RCC1314, RCC1346, RCC1489, RCC1511, RCC1546, RCC1557, RCC1614, rcc1731, RCC191, RCC2570, RCC3598, RCC3696, RCC3776, RCC3780, RCC4207, RCC4221, RCC4273, RCC4657, RCC4660, RCC6, RCC623, RCC6516, RCC656, RCC678, RCC69, RCC74, RCC76, RCC8, RCC80, RCC81, RCC88, RCC911, RCC950},
	doi = {10.1002/lom3.10572},
	url = {https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lom3.10572},
	author = {Barton, Samuel and Yang, Minjun and Chen, Haotian and Batchelor-McAuley, Christopher and Compton, Richard and Bouman, Heather and Rickaby, Rosalind}
}
@article {koppelle_mixotrophy_2022,
	title = {Mixotrophy in the bloom-forming genus Phaeocystis and other haptophytes},
	journal = {Harmful Algae},
	volume = {117},
	year = {2022},
	pages = {102292},
	abstract = {Phaeocystis is a globally widespread marine phytoplankton genus, best known for its colony-forming species that can form large blooms and odorous foam during bloom decline. In the North Sea, Phaeocystis globosa typically becomes abundant towards the end of the spring bloom, when nutrients are depleted and the share of mixo- trophic protists increases. Although mixotrophy is widespread across the eukaryotic tree of life and is also found amongst haptophytes, a mixotrophic nutrition has not yet been demonstrated in Phaeocystis. Here, we sampled two consecutive Phaeocystis globosa spring blooms in the coastal North Sea. In both years, bacterial cells were observed inside 0.6 {\textendash} 2\% of P. globosa cells using double CARD-FISH hybridizations in combination with laser scanning confocal microscopy. Incubation experiments manipulating light and nutrient availability showed a trend towards higher occurrence of intracellular bacteria under P-deplete conditions. Based on counts of bacteria inside P. globosa cells in combination with theoretical values of prey digestion times, maximum ingestion rates of up to 0.08 bacteria cell- 1 h- 1 were estimated. In addition, a gene-based predictive model was applied to the transcriptome assemblies of seven Phaeocystis strains and 24 other haptophytes to assess their trophic mode. This model predicted a phago-mixotrophic feeding strategy in several (but not all) strains of P. globosa, P. antarctica and other haptophytes that were previously assumed to be autotrophic. The observation of bacterial cells inside P. globosa and the gene-based model predictions strongly suggest that the phago-mixotrophic feeding strategy is widespread among members of the Phaeocystis genus and other haptophytes, and might contribute to their remarkable success to form nuisance blooms under nutrient-limiting conditions.},
	keywords = {RCC1130, RCC1303, rcc1383, RCC1455, RCC1486, RCC1523, RCC1537, RCC918},
	issn = {15689883},
	doi = {10.1016/j.hal.2022.102292},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S1568988322001202},
	author = {Koppelle, Sebastiaan and L{\'o}pez-Escard{\'o}, David and Brussaard, Corina P.D. and Huisman, Jef and Philippart, Catharina J.M. and Massana, Ramon and Wilken, Susanne}
}
@article {eyal_variability_2022,
	title = {The variability in the structural and functional properties of coccolith base plates},
	journal = {Acta Biomaterialia},
	volume = {148},
	year = {2022},
	pages = {336{\textendash}344},
	abstract = {Biomineralization processes exert varying levels of control over crystallization, ranging from poorly ordered polycrystalline arrays to intricately shaped single crystals. Coccoliths, calcified scales formed by unicellular algae, are a model for a highly controlled crystallization process. The coccolith crystals nucleate next to an organic oval structure that was termed the base plate, leading to the assumption that it is responsible for the oriented nucleation of the crystals via stereochemical interactions. In recent years, several works focusing on a well-characterized model species demonstrated a fundamental role for indirect interactions that facilitate coccolith crystallization. Here, we developed the tools to extract the base plates from five different species, giving the opportunity to systematically explore the relations between base plate and coccolith properties. We used multiple imaging techniques to evaluate the structural and chemical features of the base plates under native hydrated conditions. The results show a wide range of properties, overlaid on a common rudimentary scaffold that lacks any detectable structural or chemical motifs that can explain direct nucleation control. This work emphasizes that it is the combination between the base plate and the chemical environment inside the cell that cooperatively facilitate the exquisite control over the crystallization process. Statement of significance Biological organic scaffolds can serve as functional surfaces that guide the formation of inorganic materials. However, in many cases the specific interactions that facilitate such tight regulation are complex and not fully understood. In this work, we elucidate the architecture of such amodel biological template, an organic scale that directs the assembly of exquisite crystalline arrays of marine microalgae. By using cryo electron microscopy, we reveal the native state organization of these scales from several species. The observed similarities and differences allow us to propose that the chemical microenvironment, rather than stereochemical matching, is the pivotal regulator of the process.},
	keywords = {biomineralization, Calcite, Coccoliths, Cryo electron tomography, Crystallization, RCC1130, RCC1181, RCC190, RCC3777},
	issn = {1742-7061},
	doi = {10.1016/j.actbio.2022.06.027},
	url = {https://www.sciencedirect.com/science/article/pii/S174270612200366X},
	author = {Eyal, Zohar and Krounbi, Leilah and Ben Joseph, Oz and Avrahami, Emanuel M. and Pinkas, Iddo and Peled-Zehavi, Hadas and Gal, Assaf}
}
@article {yang_opto-electrochemical_2021,
	title = {Opto-Electrochemical Dissolution Reveals Coccolith Calcium Carbonate Content},
	journal = {Angewandte Chemie International Edition},
	volume = {60},
	number = {38},
	year = {2021},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.202108435},
	pages = {20999{\textendash}21006},
	abstract = {Coccoliths are plates of biogenic calcium carbonate secreted by calcifying marine phytoplankton; annually these phytoplankton are responsible for exporting >1 billion tonnes (1015 g) of calcite to the deep ocean. Rapid and reliable methods for assessing the degree of calcification are technically challenging because the coccoliths are micron sized and contain picograms (pg) of calcite. Here we pioneer an opto-eletrochemical acid titration of individual coccoliths which allows 3D reconstruction of each individual coccolith via in situ optical imaging enabling direct inference of the coccolith mass. Coccolith mass ranging from 2 to 400 pg are reported herein, evidencing both inter- and intra-species variation over four different species. We foresee this scientific breakthrough, which is independent of knowledge regarding the species and calibration-free, will allow continuous monitoring and reporting of the degree of coccolith calcification in the changing marine environment.},
	keywords = {analytical methods, calcite dissolution, electrochemistry, global carbonate cycle, marine phytoplankton, RCC1130, RCC1198, RCC1216, RCC1314},
	issn = {1521-3773},
	doi = {10.1002/anie.202108435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202108435},
	author = {Yang, Minjun and Batchelor-McAuley, Christopher and Barton, Samuel and Rickaby, Rosalind E. M. and Bouman, Heather A. and Compton, Richard G.}
}
@article {Avrahami2020,
	title = {Detection of phagotrophy in the marine phytoplankton group of the coccolithophores (calcihaptophycidae, haptophyta) during Nutrient-replete and Phosphate-limited growth},
	journal = {Journal of Phycology},
	year = {2020},
	note = {tex.mendeley-tags: RCC1130,RCC1131,RCC1178,RCC1216,RCC1217,RCC3779},
	month = {apr},
	pages = {jpy.12997},
	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 ({\textexclamdown}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.},
	keywords = {bacterivory, coccolithophores, life cycle, mixotrophy, phytoplankton, RCC1130, RCC1131, RCC1178, RCC1216, rcc1217, RCC3779},
	issn = {0022-3646},
	doi = {10.1111/jpy.12997},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.12997},
	author = {Avrahami, Yoav and Frada, Miguel J.},
	editor = {Mock, T.}
}
@article {BlancoAmeijeiras2020,
	title = {Influence of temperature and CO 2 on Plasma-membrane permeability to CO 2 and HCO 3 - in the marine haptophytes emiliania huxleyi and calcidiscus leptoporus (prymnesiophyceae)},
	journal = {Journal of Phycology},
	year = {2020},
	note = {tex.mendeley-tags: RCC1130,RCC1258},
	month = {jun},
	pages = {jpy.13017},
	abstract = {Membrane permeabilities to CO2 and HCO3- constrain the function of CO2 concentrating mechanisms that algae use to supply inorganic carbon for photosynthesis. In diatoms and green algae, plasma membranes are moderately to highly permeable to CO2 but effectively impermeable to HCO3-. Here, CO2 and HCO3- membrane permeabilities were measured using an 18O-exchange technique on two species of haptophyte algae, Emiliania huxleyi and Calcidiscus leptoporus, which showed that the plasma membranes of these species are also highly permeable to CO2 (0.006{\textendash}0.02 cm ? s-1) but minimally permeable to HCO3-. Increased temperature and CO2 generally increased CO2 membrane permeabilities in both species, possibly due to changes in lipid composition or CO2 channel proteins. Changes in CO2 membrane permeabilities showed no association with the density of calcium carbonate coccoliths surrounding the cell, which could potentially impede passage of compounds. Haptophyte plasma-membrane permeabilities to CO2 were somewhat lower than those of diatoms but generally higher than membrane permeabilities of green algae. One caveat of these measurements is that the model used to interpret 18O-exchange data assumes that carbonic anhydrase, which catalyzes 18O-exchange, is homogeneously distributed in the cell. The implications of this assumption were tested using a two-compartment model with an inhomogeneous distribution of carbonic anhydrase to simulate 18O-exchange data and then inferring plasma-membrane CO2 permeabilities from the simulated data. This analysis showed that the inferred plasma-membrane CO2 permeabilities are minimal estimates but should be quite accurate under most conditions.},
	keywords = {carbon concentrating mechanism, CO2, haptophyte, membrane, PERMEABILITY, RCC1130, rcc1258},
	issn = {0022-3646},
	doi = {10.1111/jpy.13017},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.13017},
	author = {Blanco-Ameijeiras, Sonia and Stoll, Heather M. and Zhang, Hongrui and Hopkinson, Brian M.},
	editor = {Raven, J.}
}
@article {Gafar2019,
	title = {Particulate inorganic to organic carbon production as a predictor for coccolithophorid sensitivity to ongoing ocean acidification},
	journal = {Limnology and Oceanography Letters},
	volume = {4},
	number = {3},
	year = {2019},
	note = {Publisher: John Wiley \& Sons, Ltd tex.mendeley-tags: RCC1130,RCC1141,RCC1168,RCC1198,RCC1200,RCC1323,RCC1334},
	month = {jun},
	pages = {62{\textendash}70},
	abstract = {Ocean acidification (OA) can induce shifts in plankton community composition, with coccolithophores being mostly negatively impacted. This is likely to change particulate inorganic and organic carbon (PIC and POC, respectively) production, with impacts on the biological carbon pump. Hence, assessing and, most importantly, understanding species-specific sensitivities of coccolithophores is paramount. In a multispecies comparison, spanning more than two orders of magnitude in terms of POC and PIC production rates, among Calcidiscus leptoporus, Coccolithus pelagicus subsp. braarudii, Emiliania huxleyi, Gephyrocapsa oceanica, and Scyphosphaera apsteinii, we found that cellular PIC : POC was a good predictor for a species{\textquoteright} OA sensitivity. This is likely related to the need for cellular pH homeostasis, which is challenged by the process of calcification producing protons internally, especially when seawater pH decreases in an OA scenario. With higher PIC : POC, species and strains being more sensitive to OA coccolithophores may shift toward less calcified varieties in the future.},
	keywords = {RCC1130, RCC1141, RCC1168, RCC1198, RCC1200, RCC1323, RCC1334},
	issn = {2378-2242},
	doi = {10.1002/lol2.10105},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/lol2.10105},
	author = {Gafar, N. A. and Eyre, B. D. and Schulz, K. G.}
}
@article {Fox2018,
	title = {Calcein staining as a tool to investigate coccolithophore calcification},
	journal = {Frontiers in Marine Science},
	volume = {5},
	number = {September},
	year = {2018},
	note = {tex.mendeley-tags: RCC 1461,RCC 3777,RCC1130,RCC1303,RCC1456},
	abstract = {This brief paper summarizes the literature on academic accommodations for students with psychiatric disabilities. A definition of psychiatric disability precedes a brief summary of the following specific psychiatric diagnoses: depression, bipolar affective disorder; borderline personality disorder; schizophrenia; and anxiety disorders. Also noted are behavior or personality disorders specifically excluded from coverage under the Americans with Disabilities Act. Functional limitations of this population that may affect academic performance are then listed and defined. Among these are medication side effects, sustaining concentration, maintaining stamina, interacting with others, responding to negative feedback, responding to change, and severe test anxiety. Examples of appropriate instructional strategies are followed by a discussion of reasonable accommodations to provide these students with equal access to the curriculum. Examples are then given of classroom accommodations, examination accommodations, and assignment accommodations. Characteristics of accommodations that are not reasonable are also listed. The paper concludes with a resource list including Web site and contact information for the DO-IT (Disabilities, Opportunities, Internetworking, and Technology) Project. (DB)},
	keywords = {bet hedging, calcein, Calcification, coccolith, coccolithophore, flow cytometry, haptophyte, RCC1130, RCC1303, RCC1456, RCC1461, RCC3777, secretion},
	issn = {2296-7745},
	doi = {10.3389/fmars.2018.00326},
	url = {https://www.frontiersin.org/article/10.3389/fmars.2018.00326/full},
	author = {Fox, Emily and Meyer, Erin and Panasiak, Natalie and Taylor, Alison R.}
}
@article {Durak2016,
	title = {A role for diatom-like silicon transporters in calcifying coccolithophores},
	journal = {Nature Communications},
	volume = {7},
	number = {February},
	year = {2016},
	note = {tex.mendeley-tags: 2016,RCC1130,RCC1303,RCC1453,RCC1456,RCC3432},
	pages = {10543},
	abstract = {Biomineralisation by marine phytoplankton, such as the silicifying diatoms and calcifying coccolithophores, plays an important role in carbon and nutrient cycling in the oceans. Silicification and calcification are distinct cellular processes with no known common mechanisms. As a result, it is thought that coccolithophores are able to outcompete diatoms in Si-depleted waters, which can contribute to the formation of coccolithophore blooms. Here, we show that an expanded family of diatom-like silicon transporters (SITs) are present in both silicifying and calcifying haptophyte phytoplankton, including some coccolithophores of global ecological importance. We find an essential role for Si in calcification in these coccolithophores, indicating that Si uptake contributes to the very different forms of biomineralisation in diatoms and coccolithophores. However, SITs and the requirement for Si are significantly absent from the highly abundant bloom-forming coccolithophores, such as Emiliania huxleyi. These very different requirements for Si in coccolithophores are likely to have major influence on their competitive interactions with diatoms and other siliceous phytoplankton.},
	keywords = {(RCC1130, (RCC1456), 2016, biomineralisation, coccolithophores, Gephyrocapsa oceanica (RCC1303) and Scyphosphaera, haptophytes, RCC1130, RCC1303, RCC1453, RCC1456, RCC3432, silica, TMR5 (RCC3432{\textemdash}Sea of Japan) and PZ241 (RCC1453{\textemdash}Med},
	issn = {2041-1723},
	doi = {10.1038/ncomms10543},
	author = {Durak, Grazyna M and Taylor, Alison R and Probert, Ian and de Vargas, Colomban and Audic, St{\'e}phane and Schroeder, Declan C and Brownlee, Colin and Wheeler, Glen L}
}
