@article {dedman_alterations_2024,
	title = {Alterations in metalloprotein abundance under ocean warming in the marine green alga Micromonas pusilla using the mebipred predictive tool},
	journal = {Algal Research},
	volume = {78},
	year = {2024},
	month = {mar},
	pages = {103412},
	abstract = {Metals are essential to life, required for the functioning of a substantial fraction of proteins. Marine phytoplankton drives the oceanic carbon cycle, influencing global biogeochemistry. These organisms rely on trace metal nutrients; however how trace nutrient demand will change under ocean warming is uncertain. The currently limited annotation of metalloproteins contributes to this lack of understanding. Herein, we utilise the recently published mebipred tool to predict the metalloproteome of the globally occurring green alga, Micromonas pusilla, revealing \~{}20~\% of its reference proteome to display ion-binding properties. Using the predicted metalloproteome, and existing Gene Ontology annotation, we present a comprehensive insight towards changes in metalloprotein abundance after exposure to ocean warming conditions (+6~{\textdegree}C), using a shotgun proteomic approach. We outline that predictions must be combined with existing annotation to fully capture the metalloprotein response. Approximately 50~\% of identified metalloproteins significantly altered in abundance under warming, largely related to changes in cellular function. Notably, warming appeared to shift Fe use from photosynthesis to storage in M. pusilla, indicated by a 2.36 log2 fold-increase in ferritin and decline in abundance of photosynthetic proteins. Ocean warming will inevitably alter cellular use and demand for metal cofactors in marine phytoplankton with possible implications for biogeochemical cycling. Bioinformatics tools such as mebipred greatly expand our ability to examine such changes.},
	keywords = {Biogeochemistry, marine phytoplankton, Ocean warming, proteomics, RCC1614, Trace metals},
	issn = {2211-9264},
	doi = {10.1016/j.algal.2024.103412},
	url = {https://www.sciencedirect.com/science/article/pii/S2211926424000249},
	author = {Dedman, Craig J. and Fournier, Marjorie and Rickaby, Rosalind E. M.}
}
@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.}
}
@article {yu_does_2023,
	title = {Does the life cycle stage matter for distinguishing phytoplankton via fluoro-electrochemical microscopy?},
	journal = {Cell Reports Physical Science},
	year = {2023},
	pages = {101223},
	abstract = {Phytoplankton have species-specific responses toward electrogenerated oxidants, allowing high-throughput species analysis. Herein, a fluoro-electrochemical method is used to expose single Chlamydomonas concordia vegetative cells at different points within their life cycle to electro-generated oxidants from seawater. The resulting decay in fluorescence from chlorophyll-a is measured as a function of time and drops to zero for phytoplankton adjacent to the electrode over a period of a few seconds. The chlorophyll-a transient timescale allows mother cells, which are distinctively larger and require a larger quantity of oxidants, to be distinguished from either zoospores or {\textquotedblleft}growing{\textquotedblright} cells, while all the cells show the same intrinsic susceptibility modulated only by the size of the phytoplankton. These observations are essential for the future automated characterization of the speciation of phytoplankton populations as they show that there is no need to manually identify the life cycle stage.},
	keywords = {electrogenerated radicals, fluoro-electrochemistry, Green algae, life cycle, marine phytoplankton, oxidative damage, RCC1, remote sensing, susceptibility library},
	issn = {2666-3864},
	doi = {10.1016/j.xcrp.2022.101223},
	url = {https://www.sciencedirect.com/science/article/pii/S2666386422005410},
	author = {Yu, Jiahao and Yang, Minjun and Batchelor-McAuley, Christopher and Barton, Samuel and Rickaby, Rosalind E. M. and Bouman, Heather A. and Compton, Richard G.}
}
@article {dedman_shotgun_2023,
	title = {Shotgun proteomics reveals temperature-dependent regulation of major nutrient metabolism in coastal Synechococcus sp. WH5701},
	journal = {Algal Research},
	year = {2023},
	month = {oct},
	pages = {103279},
	abstract = {Marine cyanobacteria are major contributors to the oceanic carbon sink and are predicted to increase in numbers in the future warmed ocean. As a result, the influence of marine cyanobacteria on marine biogeochemical cycling will likely be enhanced. Associated with elevations in temperature the ocean will undergo increased stratification, reducing supply of essential nutrients to upper phototrophic layers. It is therefore critical that we resolve the manners by which cyanobacteria respond to variations in temperature, and consequences for major nutrient metabolism which may ultimately direct global biogeochemistry and trophic transfer. In this study we use the coastal Synechococcus sp. WH5701 to examine proteomic alterations in major nutrient (C, N and P) metabolic pathways following exposure to varying temperature. In response to temperature treatments, Synechococcus displayed higher rates of growth and photosynthetic efficiency when temperatures were raised from 17 {\textdegree}C to 23 {\textdegree}C and 28 {\textdegree}C, associated with a significant \textasciitilde30{\textendash}40 \% alteration in the cellular proteome. As temperatures increased, proteomic investment towards photosynthetic machinery appeared up-regulated, whilst abundance of RuBisCO was reduced, associated with an apparent alteration in CCM composition and carbon metabolism. N demand appeared to increase in-line with temperature, associated with alterations in the GS-GOGAT pathway, likely due to increased demand for and efficiency of protein synthesis. In contrast, P demand at the highest temperature appeared reduced as investment in the ribosome declines due to improved translation efficiency, whilst luxury P-storage appeared a feature of growth at low temperature. It appears likely that as seawater temperatures rise under ocean warming, the biochemical composition of cyanobacteria will be altered, increasing cellular C- and N- to P ratios, ultimately impacting upon their contribution to oceanic biogeochemical cycling.},
	keywords = {climate change, Ocean warming, phytoplankton, Proteomics: Marine biogeochemistry, rcc1084},
	issn = {2211-9264},
	doi = {10.1016/j.algal.2023.103279},
	url = {https://www.sciencedirect.com/science/article/pii/S2211926423003120},
	author = {Dedman, Craig J. and Barton, Samuel and Fournier, Marjorie and Rickaby, Rosalind E. M.}
}
@article {zhang_stimulating_2023,
	title = {Stimulating and toxic effect of chromium on growth and photosynthesis of a marine chlorophyte},
	journal = {New Phytologist},
	volume = {n/a},
	number = {n/a},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/nph.19376},
	abstract = {Marine phytoplankton can interchange trace metals in various biochemical functions, particularly under metal-limiting conditions. Here, we investigate the stimulating and toxicity effect of chromium (Cr) on a marine Chlorophyceae Osetreococcus tauri under Fe-replete and Fe-deficient conditions. We determined the growth, photosynthesis, and proteome expressions of Osetreococcus tauri cultured under different Cr and Fe concentrations. In Fe-replete conditions, the presence of Cr(VI) stimulated significantly the growth rate and the maximum yield of photochemistry of photosystem II (Fv/Fm) of the phytoplankton, while the functional absorption cross-section of photosystem II (σPSII) did not change. Minor additions of Cr(VI) partially rescued phytoplankton growth under Fe-limited conditions. Proteomic analysis of this alga grown in Fe-replete normal and Fe-replete with Cr addition media (10 μM Cr) showed that the presence of Cr significantly decreased the expression of phosphate-transporting proteins and photosynthetic proteins, while increasing the expression of proteins related to carbon assimilation. Cr can stimulate the growth and photosynthesis of O. tauri, but the effects are dependent on both the Cr(VI) concentration and the availability of Fe. The proteomic results further suggest that Cr(VI) addition might significantly increase starch production and carbon fixation.},
	keywords = {chromium, Photosynthesis, phytoplankton, proteomics, RCC1, RCC1242, trace metal},
	issn = {1469-8137},
	doi = {10.1111/nph.19376},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/nph.19376},
	author = {Zhang, Qiong and Charles, Philip D. and Bendif, El Mahdi and Hester, Svenja S. and Mohammad, Shabaz and Rickaby, Rosalind E. M.}
}
@article {fan_quantifying_2022,
	title = {Quantifying the Extent of Calcification of a Coccolithophore Using a Coulter Counter},
	journal = {Analytical Chemistry},
	year = {2022},
	month = {sep},
	pages = {acs.analchem.2c01971},
	abstract = {Although, in principle, the Coulter Counter technique yields an absolute measure of particle volume, in practice, calibration is nearuniversally employed. For regularly shaped and non-biological samples, the use of latex beads for calibration can provide sufficient accuracy. However, this is not the case with particles encased in biogenically formed calcite. To date, there has been no effective route by which a Coulter Counter can be calibrated to enable the calcification of coccolithophores�single cells encrusted with biogenic calcite�to be quantified. Consequently, herein, we seek to answer the following question: to what extent can a Coulter Counter be used to provide accurate information regarding the calcite content of a singlespecies coccolithophore population? Through the development of a new calibration methodology, based on the measurement and dynamic tracking of the acid-driven calcite dissolution reaction, a route by which the cellular calcite content can be determined is presented. This new method allows, for the first time, a Coulter Counter to be used to yield an absolute measurement of the amount of calcite per cell.},
	keywords = {RCC1198, RCC1216, RCC1314},
	issn = {0003-2700, 1520-6882},
	doi = {10.1021/acs.analchem.2c01971},
	url = {https://pubs.acs.org/doi/10.1021/acs.analchem.2c01971},
	author = {Fan, Xinmeng and Batchelor-McAuley, Christopher and Yang, Minjun and Barton, Samuel and Rickaby, Rosalind E. M. and Bouman, Heather A. and Compton, Richard G.}
}
@article {tostevin_influence_2021,
	title = {The influence of elevated SiO2(aq) on intracellular silica uptake and microbial metabolism},
	journal = {Geobiology},
	volume = {n/a},
	number = {n/a},
	year = {2021},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12442},
	abstract = {Microbes are known to accumulate intracellular SiO2(aq) up to 100s of mmol/l from modern seawater (SiO2(aq) <100 {\textmu}mol/l), despite having no known nutrient requirement for Si. Before the evolution of siliceous skeletons, marine silica concentrations were likely an order of magnitude higher than the modern ocean, raising the possibility that intracellular SiO2(aq) accumulation interfered with normal cellular function in non-silicifying algae. Yet, because few culturing studies have isolated the effects of SiO2(aq) at high concentration, the potential impact of elevated marine silica on early microbial evolution is unknown. Here, we test the influence of elevated SiO2(aq) on eukaryotic algae, as well as a prokaryote species. Our results demonstrate that under SiO2(aq) concentrations relevant to ancient seawater, intracellular Si accumulates to concentrations comparable to those found in siliceous algae such as diatoms. In addition, all eukaryotic algae showed a statistically significant response to the high-Si treatment, including reduced average cell sizes and/or a reduction in the maximum growth rate. In contrast, there was no consistent response to the high-Si treatment by the prokaryote species. Our results highlight the possibility that elevated marine SiO2(aq) may have been an environmental stressor during early eukaryotic evolution.},
	keywords = {Archaean, culturing, microbial metabolism, Proterozoic, RCC1, RCC1216, rcc1512, RCC1547, rcc539, silica},
	issn = {1472-4669},
	doi = {10.1111/gbi.12442},
	url = {http://onlinelibrary.wiley.com/doi/abs/10.1111/gbi.12442},
	author = {Tostevin, Rosalie and Snow, Joseph T. and Zhang, Qiong and Tosca, Nicholas J. and Rickaby, Rosalind E. M.}
}
@article {filatov_mode_2021,
	title = {The mode of speciation during a recent radiation in open-ocean phytoplankton},
	journal = {Current Biology},
	year = {2021},
	month = {oct},
	abstract = {Despite the enormous ecological importance of marine phytoplankton, surprisingly little is known about how new phytoplankton species originate and evolve in the open ocean, in the absence of apparent geographic barriers that typically act as isolation mechanisms in speciation. To investigate the mechanism of open-ocean speciation, we combined fossil and climatic records from the late Quaternary with genome-wide evolutionary genetic analyses of speciation in the ubiquitous and abundant pelagic coccolithophore genus Gephyrocapsa (including G. huxleyi, formerly known as Emiliania huxleyi). Based on the analysis of 43 sequenced genomes, we report that the best-fitting scenario for all speciation events analyzed included an extended period of complete isolation followed by recent (Holocene) secondary contact, supporting the role of geographic or oceanographic barriers in population divergence and speciation. Consistent with this, fossil data reveal considerable diachroneity of species first occurrence. The timing of all speciation events coincided with glacial phases of glacial-interglacial cycles, suggesting that stronger isolation between the ocean basins and increased segregation of ecological niches during glaciations are important drivers of speciation in marine phytoplankton. The similarity across multiple speciation events implies the generality of this inferred speciation scenario for marine phytoplankton.},
	keywords = {phytoplankton, population genetic modeling, rcc1212, rcc1238, RCC1239, RCC1253, RCC1281, RCC1296, RCC1310, RCC1314, RCC1562, RCC1836, RCC3370, RCC3711, RCC3733, RCC3862, RCC3898, RCC4002, RCC4028, RCC4030, RCC4032, RCC4033, RCC4034, RCC4035, RCC4036, RCC5119, RCC5134, RCC5137, RCC5141, RCC6566, RCC6730, secondary contact, sequence polymorphism, speciation},
	issn = {0960-9822},
	doi = {10.1016/j.cub.2021.09.073},
	url = {https://www.sciencedirect.com/science/article/pii/S0960982221013415},
	author = {Filatov, Dmitry A. and Bendif, El Mahdi and Archontikis, Odysseas A. and Hagino, Kyoko and Rickaby, Rosalind E. M.}
}
@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 {bendif_repeated_2019,
	title = {Repeated species radiations in the recent evolution of the key marine phytoplankton lineage Gephyrocapsa},
	journal = {Nature Communications},
	volume = {10},
	number = {1},
	year = {2019},
	pages = {4234},
	abstract = {Abstract Phytoplankton account for nearly half of global primary productivity and strongly affect the global carbon cycle, yet little is known about the forces that drive the evolution of these keystone microscopic organisms. Here we combine morphometric data from the fossil record of the ubiquitous coccolithophore genus Gephyrocapsa with genomic analyses of extant species to assess the genetic processes underlying Pleistocene palaeontological patterns. We demonstrate that all modern diversity in Gephyrocapsa (including Emiliania huxleyi ) originated in a rapid species radiation during the last 0.6 Ma, coincident with the latest of the three pulses of Gephyrocapsa diversification and extinction documented in the fossil record. Our evolutionary genetic analyses indicate that new species in this genus have formed in sympatry or parapatry, with occasional hybridisation between species. This sheds light on the mode of speciation during evolutionary radiation of marine phytoplankton and provides a model of how new plankton species form.},
	keywords = {RCC1253, RCC1296, RCC3370, RCC3711, RCC4028, RCC4030, RCC4032, RCC4033, RCC4034},
	issn = {2041-1723},
	doi = {10.1038/s41467-019-12169-7},
	url = {https://www.nature.com/articles/s41467-019-12169-7},
	author = {Bendif, El Mahdi and Nevado, Bruno and Wong, Edgar L. Y. and Hagino, Kyoko and Probert, Ian and Young, Jeremy R. and Rickaby, Rosalind E. M. and Filatov, Dmitry A.}
}
@article {Wilson2019,
	title = {Susceptibility of algae to Cr toxicity reveals contrasting metal management strategies},
	journal = {Limnology and Oceanography},
	volume = {64},
	number = {5},
	year = {2019},
	note = {Publisher: John Wiley \& Sons, Ltd tex.mendeley-tags: RCC1,RCC1242,RCC4221,RCC950},
	month = {sep},
	pages = {2271{\textendash}2282},
	abstract = {At the Paleozoic{\textendash}Mesozoic boundary, the dominance of marine eukaryotic algae shifted from the green (chlorophyll b) to the red (chlorophyll c) superfamily. Selection pressures caused by the bioavailability of trace metals associated with increasing oxygenation of the ocean may have played a key role in this algal revolution. From a scan of elemental compositions, a significant difference in the cellular Cr/P quota was found between the two superfamilies. Here, the different responses to high levels of Cr exposure reveal contrasting strategies for metal uptake and homeostasis in these algal lineages. At high Cr(VI) concentrations, red lineages experience growth inhibition through reduced photosynthetic capability, while green lineages are completely unaffected. Moreover, Cr(VI) has a more significant impact on the metallomes of red lineage algae, in which metal/P ratios increased with increasing Cr(VI) concentration for many trace elements. Green algae have higher specificity transporters to prevent Cr(VI) from entering the cell, and more specific intracellular stores of Cr within the membrane fraction than the red algae, which accumulate more Cr mistakenly in the cytosol fraction via lower affinity transport mechanisms. Green algal approaches require greater nutrient investments in the more numerous transport proteins required and management of specific metals, a strategy better adapted to the resource-rich coastal waters. By contrast, the red algae are nutrient-efficient with fewer and less discriminate metal transporters, which can be fast and better adapted in the oligotrophic, oxygenated open ocean, which has prevailed since the deepening of the oxygen minimum zones at the start of the Mesozoic era.},
	keywords = {RCC1, RCC1242, RCC4221, RCC950},
	issn = {0024-3590},
	doi = {10.1002/lno.11183},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/lno.11183},
	author = {Wilson, Will and Zhang, Qiong and Rickaby, Rosalind E. M.}
}
