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Juliet Brodie - One of the best experts on this subject based on the ideXlab platform.
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Corallina Corallinales rhodophyta from tristan da cunha and the falkland islands implications for south atlantic biogeography
European Journal of Phycology, 2021Co-Authors: Juliet Brodie, Stephen J Russell, Leanne A Melbourne, Robert J Mrowicki, Paul Brickle, Sue ScottAbstract:A molecular and morphological taxonomic study of Corallina (Corallinales, Rhodophyta) from Tristan da Cunha and the Falkland Islands revealed Corallina chamberlainiae J.Brodie & R.Mrowicki sp. nov....
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mitochondrial and plastid genome variability of Corallina officinalis Corallinales rhodophyta
Applied Phycology, 2020Co-Authors: Chris Yesson, Christopher Williamson, Andrew G Briscoe, Xueni Bian, Juliet BrodieAbstract:Corallina officinalis is a calcifying red alga, common in tide pools in the North Atlantic with occasional reports from the north-east Pacific. It is an important habitat-forming alga, providing sh...
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photoacclimation and photoregulation strategies of Corallina Corallinales rhodophyta across the ne atlantic
European Journal of Phycology, 2018Co-Authors: Christopher Williamson, Marian L Yallop, R G Perkins, Cesar Peteiro, Noemi Sanchez, Karl Gunnarsson, Maggie L Gamble, Juliet BrodieAbstract:This study characterizes the photoacclimation and photoregulation mechanisms that allow calcified macroalgae of the genus Corallina (Corallinales, Rhodophyta) to dominate rock pool habitats across the NE Atlantic despite the highly variable irradiance regimes experienced. Rapid light curves (RLCs) were performed with pulse amplitude modulation (PAM) fluorometry in situ across a full seasonal cycle in the UK intertidal with C. officinalis and C. caespitosa. Latitudinal comparisons were performed across the full extent of C. officinalis’ range in the NE Atlantic (Iceland–northern Spain), and for C. caespitosa in northern Spain. Ex situ RLCs with dark recovery were further employed to assess the optimal, as compared with actual, photophysiology across seasons and latitudes. Corallina species were shown to photoacclimate at seasonal timescales to changing irradiance, increasing light-harvesting during low-light autumn/winter periods and protecting photosystems during high-light summer conditions. Seasonal photoacclimation was achieved through alteration in the number of photosystem (PS) units (PSII and light harvesting antennae) over time. Non-photochemical quenching (NPQ) served as an important photoregulation mechanism utilized by Corallina to prevent or minimize photoinhibition over shorter time scales (seconds–hours), though the efficiency of NPQ was dependent on the seasonal-acclimated state. With increasing latitude the efficiency of photoregulation decreased, representing potential differential photoadaptation of Corallina across species ranges in the NE Atlantic. In contrast, highly conserved inter-specific patterns in photophysiological responses to irradiance were apparent. This study demonstrates the photophysiological mechanisms allowing Corallina to optimize use of the variable irradiance conditions apparent in rock pool environments, when and how they are employed, and their limitations.
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snps reveal geographical population structure of Corallina officinalis Corallinaceae rhodophyta
European Journal of Phycology, 2018Co-Authors: Chris Yesson, Amy Jackson, Stephen J Russell, Christopher Williamson, Juliet BrodieAbstract:We present the first population genetics study of the calcifying coralline alga and ecosystem engineer Corallina officinalis. Eleven novel SNP markers were developed and tested using Kompetitive Al...
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the regulation of coralline algal physiology an in situ study of Corallina officinalis Corallinales rhodophyta
Biogeosciences, 2017Co-Authors: Christopher Williamson, Marian L Yallop, R G Perkins, Matthew Voller, Juliet BrodieAbstract:Abstract. Calcified macroalgae are critical components of marine ecosystems worldwide, but face considerable threat both from climate change (increasing water temperatures) and ocean acidification (decreasing ocean pH and carbonate saturation). It is thus fundamental to constrain the relationships between key abiotic stressors and the physiological processes that govern coralline algal growth and survival. Here we characterize the complex relationships between the abiotic environment of rock pool habitats and the physiology of the geniculate red coralline alga, Corallina officinalis (Corallinales, Rhodophyta). Paired assessment of irradiance, water temperature and carbonate chemistry, with C. officinalis net production ( NP ), respiration (R) and net calcification ( NG ) was performed in a south-western UK field site, at multiple temporal scales (seasonal, diurnal and tidal). Strong seasonality was observed in NP and night-time R, with a Pmax of 22.35 µmol DIC (g DW)−1 h−1, Ek of 300 µmol photons m−2 s−1 and R of 3.29 µmol DIC (g DW)−1 h−1 determined across the complete annual cycle. NP showed a significant exponential relationship with irradiance (R2 = 0.67), although was temperature dependent given ambient irradiance > Ek for the majority of the annual cycle. Over tidal emersion periods, dynamics in NP highlighted the ability of C. officinalis to acquire inorganic carbon despite significant fluctuations in carbonate chemistry. Across all data, NG was highly predictable (R2 = 0.80) by irradiance, water temperature and carbonate chemistry, providing a NGmax of 3.94 µmol CaCO3 (g DW)−1 h−1 and Ek of 113 µmol photons m−2 s−1. Light NG showed strong seasonality and significant coupling to NP (R2 = 0.65) as opposed to rock pool water carbonate saturation. In contrast, the direction of dark NG (dissolution vs. precipitation) was strongly related to carbonate saturation, mimicking abiotic precipitation dynamics. Data demonstrated that C. officinalis is adapted to both long-term (seasonal) and short-term (tidal) variability in environmental stressors, although the balance between metabolic processes and the external environment may be significantly impacted by future climate change.
Christopher Williamson - One of the best experts on this subject based on the ideXlab platform.
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mitochondrial and plastid genome variability of Corallina officinalis Corallinales rhodophyta
Applied Phycology, 2020Co-Authors: Chris Yesson, Christopher Williamson, Andrew G Briscoe, Xueni Bian, Juliet BrodieAbstract:Corallina officinalis is a calcifying red alga, common in tide pools in the North Atlantic with occasional reports from the north-east Pacific. It is an important habitat-forming alga, providing sh...
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photoacclimation and photoregulation strategies of Corallina Corallinales rhodophyta across the ne atlantic
European Journal of Phycology, 2018Co-Authors: Christopher Williamson, Marian L Yallop, R G Perkins, Cesar Peteiro, Noemi Sanchez, Karl Gunnarsson, Maggie L Gamble, Juliet BrodieAbstract:This study characterizes the photoacclimation and photoregulation mechanisms that allow calcified macroalgae of the genus Corallina (Corallinales, Rhodophyta) to dominate rock pool habitats across the NE Atlantic despite the highly variable irradiance regimes experienced. Rapid light curves (RLCs) were performed with pulse amplitude modulation (PAM) fluorometry in situ across a full seasonal cycle in the UK intertidal with C. officinalis and C. caespitosa. Latitudinal comparisons were performed across the full extent of C. officinalis’ range in the NE Atlantic (Iceland–northern Spain), and for C. caespitosa in northern Spain. Ex situ RLCs with dark recovery were further employed to assess the optimal, as compared with actual, photophysiology across seasons and latitudes. Corallina species were shown to photoacclimate at seasonal timescales to changing irradiance, increasing light-harvesting during low-light autumn/winter periods and protecting photosystems during high-light summer conditions. Seasonal photoacclimation was achieved through alteration in the number of photosystem (PS) units (PSII and light harvesting antennae) over time. Non-photochemical quenching (NPQ) served as an important photoregulation mechanism utilized by Corallina to prevent or minimize photoinhibition over shorter time scales (seconds–hours), though the efficiency of NPQ was dependent on the seasonal-acclimated state. With increasing latitude the efficiency of photoregulation decreased, representing potential differential photoadaptation of Corallina across species ranges in the NE Atlantic. In contrast, highly conserved inter-specific patterns in photophysiological responses to irradiance were apparent. This study demonstrates the photophysiological mechanisms allowing Corallina to optimize use of the variable irradiance conditions apparent in rock pool environments, when and how they are employed, and their limitations.
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snps reveal geographical population structure of Corallina officinalis Corallinaceae rhodophyta
European Journal of Phycology, 2018Co-Authors: Chris Yesson, Amy Jackson, Stephen J Russell, Christopher Williamson, Juliet BrodieAbstract:We present the first population genetics study of the calcifying coralline alga and ecosystem engineer Corallina officinalis. Eleven novel SNP markers were developed and tested using Kompetitive Al...
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the regulation of coralline algal physiology an in situ study of Corallina officinalis Corallinales rhodophyta
Biogeosciences, 2017Co-Authors: Christopher Williamson, Marian L Yallop, R G Perkins, Matthew Voller, Juliet BrodieAbstract:Abstract. Calcified macroalgae are critical components of marine ecosystems worldwide, but face considerable threat both from climate change (increasing water temperatures) and ocean acidification (decreasing ocean pH and carbonate saturation). It is thus fundamental to constrain the relationships between key abiotic stressors and the physiological processes that govern coralline algal growth and survival. Here we characterize the complex relationships between the abiotic environment of rock pool habitats and the physiology of the geniculate red coralline alga, Corallina officinalis (Corallinales, Rhodophyta). Paired assessment of irradiance, water temperature and carbonate chemistry, with C. officinalis net production ( NP ), respiration (R) and net calcification ( NG ) was performed in a south-western UK field site, at multiple temporal scales (seasonal, diurnal and tidal). Strong seasonality was observed in NP and night-time R, with a Pmax of 22.35 µmol DIC (g DW)−1 h−1, Ek of 300 µmol photons m−2 s−1 and R of 3.29 µmol DIC (g DW)−1 h−1 determined across the complete annual cycle. NP showed a significant exponential relationship with irradiance (R2 = 0.67), although was temperature dependent given ambient irradiance > Ek for the majority of the annual cycle. Over tidal emersion periods, dynamics in NP highlighted the ability of C. officinalis to acquire inorganic carbon despite significant fluctuations in carbonate chemistry. Across all data, NG was highly predictable (R2 = 0.80) by irradiance, water temperature and carbonate chemistry, providing a NGmax of 3.94 µmol CaCO3 (g DW)−1 h−1 and Ek of 113 µmol photons m−2 s−1. Light NG showed strong seasonality and significant coupling to NP (R2 = 0.65) as opposed to rock pool water carbonate saturation. In contrast, the direction of dark NG (dissolution vs. precipitation) was strongly related to carbonate saturation, mimicking abiotic precipitation dynamics. Data demonstrated that C. officinalis is adapted to both long-term (seasonal) and short-term (tidal) variability in environmental stressors, although the balance between metabolic processes and the external environment may be significantly impacted by future climate change.
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characterising the microbiome of Corallina officinalis a dominant calcified intertidal red alga
FEMS Microbiology Ecology, 2016Co-Authors: Juliet Brodie, Christopher Williamson, Andrew G Briscoe, Rachel H Walker, Gary L A Barker, Marian L YallopAbstract:The living prokaryotic microbiome of the calcified geniculate (articulated) red alga, Corallina officinalis from the intertidal seashore is characterised for the first time based on the V6 hypervariable region of 16S rRNA. Results revealed an extraordinary diversity of bacteria associated with the microbiome. Thirty-five prokaryotic phyla were recovered, of which Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Verrucomicrobia, Firmicutes and Chloroflexi made up the core microbiome. Unclassified sequences made up 25% of sequences, suggesting insufficient sampling of the world's oceans/macroalgae. The greatest diversity in the microbiome was on the upper shore, followed by the lower shore then the middle shore, although the microbiome community composition did not vary between shore levels. The C. officinalis core microbiome was broadly similar in composition to those reported in the literature for crustose coralline algae (CCAs) and free-living rhodoliths. Differences in relative abundance of the phyla between the different types of calcified macroalgal species may relate to the intertidal versus subtidal habit of the taxa and functionality of the microbiome components. The results indicate that much work is needed to identify prokaryotic taxa, and to determine the nature of the relationship of the bacteria with the calcified host spatially, temporally and functionally.
Sangyong Kim - One of the best experts on this subject based on the ideXlab platform.
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1 8 dihydroxynaphthalene dhn melanin biosynthesis inhibitors increase erythritol production in torula Corallina and dhn melanin inhibits erythrose reductase
Applied and Environmental Microbiology, 2003Co-Authors: Jungkul Lee, Hyungmoo Jung, Sangyong KimAbstract:The yeast Torula Corallina is a strong erythritol producer that is used in the industrial production of erythritol. However, melanin accumulation during culture represents a serious problem for the purification of erythritol from the fermentation broth. Melanin biosynthesis inhibitors such as 3,4-dihydroxyphenylalanine and 1,8-dihydroxynaphthalene (DHN)-melanin inhibitors were added to the T. Corallina cultures. Only the DHN-melanin inhibitors showed an effect on melanin production, which suggests that the melanin formed during the culturing of T. Corallina is derived from DHN. This finding was confirmed by the detection of a shunt product of the pentaketide pathway, flaviolin, and elemental analysis. Among the DHN-melanin inhibitors, tricyclazole was the most effective. Supplementation with tricyclazole enhanced the production of erythritol while significantly inhibiting the production of DHN-melanin and DHN-melanin biosynthetic enzymes, such as trihydroxynaphthalene reductase. The erythrose reductase from T. Corallina was purified to homogeneity by ion-exchange and affinity chromatography. Purified erythrose reductase was significantly inhibited in vitro in a noncompetitive manner by elevated levels of DHN-melanin. In contrast, the level of erythrose reductase activity was unaffected by increasing concentrations of tricyclazole. These results suggest that supplemental tricyclazole reduces the production of DHN-melanin, which may lead to a reduction in the inhibition of erythrose reductase and a higher yield of erythritol. This is the first report to demonstrate that melanin biosynthesis inhibitors increase the production of a sugar alcohol in T. Corallina.
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Fumarate-mediated inhibition of erythrose reductase, a key enzyme for erythritol production by Torula Corallina.
Applied and environmental microbiology, 2002Co-Authors: Jungkul Lee, Bong-seong Koo, Sangyong KimAbstract:Torula Corallina, a strain presently being used for the industrial production of erythritol, has the highest erythritol yield ever reported for an erythritol-producing microorganism. The increased production of erythritol by Torula Corallina with trace elements such as Cu2+ has been thoroughly reported, but the mechanism by which Cu2+ increases the production of erythritol has not been studied. This study demonstrated that supplemental Cu2+ enhanced the production of erythritol, while it significantly decreased the production of a major by-product that accumulates during erythritol fermentation, which was identified as fumarate by instrumental analyses. Erythrose reductase, a key enzyme that converts erythrose to erythritol in T. Corallina, was purified to homogeneity by chromatographic methods, including ion-exchange and affinity chromatography. In vitro, purified erythrose reductase was significantly inhibited noncompetitively by increasing the fumarate concentration. In contrast, the enzyme activity remained almost constant regardless of Cu2+ concentration. This suggests that supplemental Cu2+ reduced the production of fumarate, a strong inhibitor of erythrose reductase, which led to less inhibition of erythrose reductase and a high yield of erythritol. This is the first report that suggests catabolite repression by a tricarboxylic acid cycle intermediate in T. Corallina.
H. Kitamura - One of the best experts on this subject based on the ideXlab platform.
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characterization of the active substances in water conditioned by the coralline red alga Corallina pilulifera as inducers of metamorphosis in larvae of the sea urchin anthocidaris crassispina
Sessile organisms, 2004Co-Authors: Siti Akmar Khadijah Ab Rahim, Cyril Glenn Satuito, H. KitamuraAbstract:Water conditioned by the coralline red alga Corallina pilulifera (C. pilulifera-conditioned water) in combination with the periphytic diatom Navicula ramosissima was found to induce metamorphosis in larvae of the sea urchin Anthocidaris crassispina. Bioassay-guided characterization of the active substances in C. pilulifera-conditioned water revealed that relatively heat-stable, non-volatile, polar substances are inducers of larval metamorphosis in A. crassispina. The molecular weights were estimated to be about 100 or less. Furthermore, fractionation by ODS column chromatography (0 to 100%, four gradients of MeOH) revealed that the activity was eluted mainly in the 0% and 70% fraction, although the activity was much lower than that of the control (C. pilulifera-conditioned water). When all four fractions (F1, F2, F3, and F4) were combined, the metamorphosis-inducing activity was recovered to almost the same level as that of the control. These results indicate that more than two metamorphosis-inducing substances may be present in C. pilulifera-conditioned water. Several authentic reagents such as phloroglucin and bromophenol did not show the metamorphosis-inducing activity even when combined with the diatom N. ramosissima.
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effect of water soluble substances extracted from the coralline red alga Corallina pilulifera on the larval metamorphosis of the sea urchin pseudocentrotus depressus
Sessile organisms, 1996Co-Authors: Hyoungbum Koh, H. Kitamura, Kazutsugu HirayamaAbstract:Water-soluble substance extracted from the coralline alga, Corallina pilulifera have the effect of induction of larval metamorphosis on the sea urchins, Pseudocentrotus depressus and Anthocidaris crassispina.The chemical cue for larval metamorphosis of P. depressus in the solution was heat stable and remained active even if its treated with organic solvent. Concentration of the potassium in an active fraction was not so high to induce the larval metamorphosis. The cue could be other inorganic ions or organic substances.
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The induction of larval settlement and metamorphosis of two sea urchins, Pseudocentrotus depressus and Anthocidaris crassispina, by free fatty acids extracted from the coralline red alga Corallina pilulifera
Marine Biology, 1993Co-Authors: H. Kitamura, S. Kitahara, H. B. KohAbstract:Lipophilic inducers of larval settlement and metamorphosis of Pseudocentrotus depressus and Anthocidaris crassispina , two commercially important sea urchin species in Japan, were isolated from the foliose coralline red alga Corallina pilulifera (collected in 1990 near Saga, Japan) and identified. Larval assays of the fractions obtained by silica gel column chromatography of the total lipids showed that non-polar groups of lipids were effective at inducing larval settlement and metamorphosis. The effective fractions were further subjected to gel filtration (Sephadex LH-20) and also to silica gel column chromatography, and the effective components isolated as single spots by thin-layer chromatography. The components at a concentration of ca. 0.4 mg paper^-1 (sample was adsorbed on a paper with 20 cm^2) induced high rates of larval settlement of both P. depressus and A. crassispina . Chemical analyses of the components revealed a mixture of free fatty acids (FFAs), dominated by eicosapentaenoic acid (20:5, 41 to 50%), palmitic acid (16:0, 11 to 17%), arachidonic acid (20:4, 9 to 15%), and palmitoleic acid (16:1, 4 to 5%). In assays with the four standard FFAs, only 20:4 and 20:5 induced larval settlement and metamorphosis of the two species, while 16:0 and 16:1 were ineffective. The larvae underwent significant rates of settlement and metamorphosis in response to the two former FFAs at levels as low as 0.18 mg paper^-1. Amongst the free fatty acid components of the alga, 20:5 was isolated as the chemical inducer of larval settlement and metamorphosis of the sea urchins in the laboratory.
Marian L Yallop - One of the best experts on this subject based on the ideXlab platform.
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photoacclimation and photoregulation strategies of Corallina Corallinales rhodophyta across the ne atlantic
European Journal of Phycology, 2018Co-Authors: Christopher Williamson, Marian L Yallop, R G Perkins, Cesar Peteiro, Noemi Sanchez, Karl Gunnarsson, Maggie L Gamble, Juliet BrodieAbstract:This study characterizes the photoacclimation and photoregulation mechanisms that allow calcified macroalgae of the genus Corallina (Corallinales, Rhodophyta) to dominate rock pool habitats across the NE Atlantic despite the highly variable irradiance regimes experienced. Rapid light curves (RLCs) were performed with pulse amplitude modulation (PAM) fluorometry in situ across a full seasonal cycle in the UK intertidal with C. officinalis and C. caespitosa. Latitudinal comparisons were performed across the full extent of C. officinalis’ range in the NE Atlantic (Iceland–northern Spain), and for C. caespitosa in northern Spain. Ex situ RLCs with dark recovery were further employed to assess the optimal, as compared with actual, photophysiology across seasons and latitudes. Corallina species were shown to photoacclimate at seasonal timescales to changing irradiance, increasing light-harvesting during low-light autumn/winter periods and protecting photosystems during high-light summer conditions. Seasonal photoacclimation was achieved through alteration in the number of photosystem (PS) units (PSII and light harvesting antennae) over time. Non-photochemical quenching (NPQ) served as an important photoregulation mechanism utilized by Corallina to prevent or minimize photoinhibition over shorter time scales (seconds–hours), though the efficiency of NPQ was dependent on the seasonal-acclimated state. With increasing latitude the efficiency of photoregulation decreased, representing potential differential photoadaptation of Corallina across species ranges in the NE Atlantic. In contrast, highly conserved inter-specific patterns in photophysiological responses to irradiance were apparent. This study demonstrates the photophysiological mechanisms allowing Corallina to optimize use of the variable irradiance conditions apparent in rock pool environments, when and how they are employed, and their limitations.
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the regulation of coralline algal physiology an in situ study of Corallina officinalis Corallinales rhodophyta
Biogeosciences, 2017Co-Authors: Christopher Williamson, Marian L Yallop, R G Perkins, Matthew Voller, Juliet BrodieAbstract:Abstract. Calcified macroalgae are critical components of marine ecosystems worldwide, but face considerable threat both from climate change (increasing water temperatures) and ocean acidification (decreasing ocean pH and carbonate saturation). It is thus fundamental to constrain the relationships between key abiotic stressors and the physiological processes that govern coralline algal growth and survival. Here we characterize the complex relationships between the abiotic environment of rock pool habitats and the physiology of the geniculate red coralline alga, Corallina officinalis (Corallinales, Rhodophyta). Paired assessment of irradiance, water temperature and carbonate chemistry, with C. officinalis net production ( NP ), respiration (R) and net calcification ( NG ) was performed in a south-western UK field site, at multiple temporal scales (seasonal, diurnal and tidal). Strong seasonality was observed in NP and night-time R, with a Pmax of 22.35 µmol DIC (g DW)−1 h−1, Ek of 300 µmol photons m−2 s−1 and R of 3.29 µmol DIC (g DW)−1 h−1 determined across the complete annual cycle. NP showed a significant exponential relationship with irradiance (R2 = 0.67), although was temperature dependent given ambient irradiance > Ek for the majority of the annual cycle. Over tidal emersion periods, dynamics in NP highlighted the ability of C. officinalis to acquire inorganic carbon despite significant fluctuations in carbonate chemistry. Across all data, NG was highly predictable (R2 = 0.80) by irradiance, water temperature and carbonate chemistry, providing a NGmax of 3.94 µmol CaCO3 (g DW)−1 h−1 and Ek of 113 µmol photons m−2 s−1. Light NG showed strong seasonality and significant coupling to NP (R2 = 0.65) as opposed to rock pool water carbonate saturation. In contrast, the direction of dark NG (dissolution vs. precipitation) was strongly related to carbonate saturation, mimicking abiotic precipitation dynamics. Data demonstrated that C. officinalis is adapted to both long-term (seasonal) and short-term (tidal) variability in environmental stressors, although the balance between metabolic processes and the external environment may be significantly impacted by future climate change.
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characterising the microbiome of Corallina officinalis a dominant calcified intertidal red alga
FEMS Microbiology Ecology, 2016Co-Authors: Juliet Brodie, Christopher Williamson, Andrew G Briscoe, Rachel H Walker, Gary L A Barker, Marian L YallopAbstract:The living prokaryotic microbiome of the calcified geniculate (articulated) red alga, Corallina officinalis from the intertidal seashore is characterised for the first time based on the V6 hypervariable region of 16S rRNA. Results revealed an extraordinary diversity of bacteria associated with the microbiome. Thirty-five prokaryotic phyla were recovered, of which Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Verrucomicrobia, Firmicutes and Chloroflexi made up the core microbiome. Unclassified sequences made up 25% of sequences, suggesting insufficient sampling of the world's oceans/macroalgae. The greatest diversity in the microbiome was on the upper shore, followed by the lower shore then the middle shore, although the microbiome community composition did not vary between shore levels. The C. officinalis core microbiome was broadly similar in composition to those reported in the literature for crustose coralline algae (CCAs) and free-living rhodoliths. Differences in relative abundance of the phyla between the different types of calcified macroalgal species may relate to the intertidal versus subtidal habit of the taxa and functionality of the microbiome components. The results indicate that much work is needed to identify prokaryotic taxa, and to determine the nature of the relationship of the bacteria with the calcified host spatially, temporally and functionally.
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Corallina and ellisolandia Corallinales rhodophyta photophysiology over daylight tidal emersion interactions with irradiance temperature and carbonate chemistry
Marine Biology, 2014Co-Authors: Christopher Williamson, Juliet Brodie, B Goss, Marian L Yallop, Sarah Lee, R G PerkinsAbstract:The photophysiology of three geniculate coralline algal species (Corallina officinalis, C. caespitosa and Ellisolandia elongata) was determined in intertidal rock pools in the south-west UK at Combe Martin (51°12′31N 4°2′19W) and Heybrook Bay (50°31′66N 4°11′41W), at the start, middle and end of summer (September 1 and 2) and winter (February 9 and 10) daylight tidal emersion periods, in relation to prevailing irradiance, temperature and carbonate chemistry conditions. Algal photophysiology was assessed from rapid light curves performed using pulse amplitude modulation fluorometry. Corallina and Ellisolandia experienced significant fluctuations in irradiance, temperature and carbonate chemistry over seasonal and tidal cycles. Rock pool carbonate chemistry was predictable (R 2 = 0.82, P < 0.0001) by photodose (summed irradiance) plus water temperature, but not significantly related to photophysiology. In contrast, Corallina and Ellisolandia relative maximum electron transfer rate showed a significant negative relationship (R 2 = 0.65, P < 0.0001) with irradiance plus water temperature. At a seasonal resolution, photoacclimation to maximize both light harvesting during winter months and photoprotection during summer months was observed for all species. Dynamic photoinhibition was apparent over both summer and winter tidal emersion, in relation to irradiance fluctuations. More effective photoinhibition was apparent during summer months, with greater sensitivity to irradiance and slower recovery in F v/F m, observed during winter. With sustained high irradiance over tidal emersion, the establishment of high pH/low inorganic carbon conditions may impact photochemistry. This study represents the first assessment of C. officinalis, C. caespitosa and E. elongata photophysiology underpinned by clear species concepts and highlights their ability to adapt to the dramatically fluctuating conditions experienced in intertidal rock pools.