%0 Journal Article %J Environmental Microbiology %D 2023 %T The Bay of Bengal exposes abundant photosynthetic picoplankton and newfound diversity along salinity-driven gradients %A Strauss, Jan %A Choi, Chang Jae %A Grone, Jonathan %A Wittmers, Fabian %A Jimenez, Valeria %A Makareviciute-Fichtner, Kriste %A Bachy, Charles %A Jaeger, Gualtiero Spiro %A Poirier, Camille %A Eckmann, Charlotte %A Spezzano, Rachele %A Löscher, Carolin R. %A Sarma, V. V. S. S. %A Mahadevan, Amala %A Worden, Alexandra Z. %K RCC393 %K RCC809 %X The Bay of Bengal (BoB) is a 2,600,000 km2 expanse in the Indian Ocean upon which many humans rely. However, the primary producers underpinning food chains here remain poorly characterized. We examined phytoplankton abundance and diversity along strong BoB latitudinal and vertical salinity gradients-which have low temperature variation (27-29°C) between the surface and subsurface chlorophyll maximum (SCM). In surface waters, Prochlorococcus averaged 11.7 ± 4.4 × 104  cells ml-1 , predominantly HLII, whereas LLII and 'rare' ecotypes, HLVI and LLVII, dominated in the SCM. Synechococcus averaged 8.4 ± 2.3 × 104  cells ml-1 in the surface, declined rapidly with depth, and population structure of dominant Clade II differed between surface and SCM; Clade X was notable at both depths. Across all sites, Ostreococcus Clade OII dominated SCM eukaryotes whereas communities differentiated strongly moving from Arabian Sea-influenced high salinity (southerly; prasinophytes) to freshwater-influenced low salinity (northerly; stramenopiles, specifically, diatoms, pelagophytes, and dictyochophytes, plus the prasinophyte Micromonas) surface waters. Eukaryotic phytoplankton peaked in the south (1.9 × 104  cells ml-1 , surface) where a novel Ostreococcus was revealed, named here Ostreococcus bengalensis. We expose dominance of a single picoeukaryote and hitherto 'rare' picocyanobacteria at depth in this complex ecosystem where studies suggest picoplankton are replacing larger phytoplankton due to climate change. %B Environmental Microbiology %G eng %R 10.1111/1462-2920.16431 %0 Journal Article %J Environmental Microbiology %D 2017 %T Quantitative biogeography of picoprasinophytes establishes ecotype distributions and significant contributions to marine phytoplankton %A Limardo, Alexander J. %A Sudek, Sebastian %A Choi, Chang Jae %A Poirier, Camille %A Rii, Yoshimi M. %A Blum, Marguerite %A Roth, Robyn %A Goodenough, Ursula %A Church, Matthew J. %A Worden, Alexandra Z. %K RCC1105 %K RCC715 %K RCC716 %K RCC809 %B Environmental Microbiology %8 jun %G eng %U http://doi.wiley.com/10.1111/1462-2920.13812 %R 10.1111/1462-2920.13812 %0 Journal Article %J Journal of Phycology %D 2014 %T Brandtodinium gen. nov. and B. nutricula comb. Nov. (Dinophyceae), a dinoflagellate commonly found in symbiosis with polycystine radiolarians %A Probert, Ian %A Siano, Raffaele %A Poirier, Camille %A Decelle, Johan %A Biard, Tristan %A Tuji, Akihiro %A Suzuki, Noritoshi %A Not, Fabrice %K Dinoflagellate %K MACUMBA %K Peridiniales %K polycystines %K Radiolaria %K rcc %K RCC3378 %K RCC3379 %K RCC3380 %K RCC3381 %K RCC3382 %K RCC3383 %K RCC3384 %K RCC3385 %K RCC3386 %K RCC3387 %K RCC3388 %K SBR$_\textrmP$hyto$_\textrmD$PO %K Scrippsiella %K symbiosis %K taxonomy %K Zooxanthella %X Symbiotic interactions between pelagic hosts and microalgae have received little attention, although they are widespread in the photic layer of the world ocean, where they play a fundamental role in the ecology of the planktonic ecosystem. Polycystine radiolarians (including the orders Spumellaria, Collodaria and Nassellaria) are planktonic heterotrophic protists that are widely distributed and often abundant in the ocean. Many polycystines host symbiotic microalgae within their cytoplasm, mostly thought to be the dinoflagellate Scrippsiella nutricula, a species originally described by Karl Brandt in the late nineteenth century as Zooxanthella nutricula. The free-living stage of this dinoflagellate has never been characterized in terms of morphology and thecal plate tabulation. We examined morphological characters and sequenced conservative ribosomal markers of clonal cultures of the free-living stage of symbiotic dinoflagellates isolated from radiolarian hosts from the three polycystine orders. In addition, we sequenced symbiont genes directly from several polycystine-symbiont holobiont specimens from different oceanic regions. Thecal plate arrangement of the free-living stage does not match that of Scrippsiella or related genera, and LSU and SSU rDNA-based molecular phylogenies place these symbionts in a distinct clade within the Peridiniales. Both phylogenetic analyses and the comparison of morphological features of culture strains with those reported for other closely related species support the erection of a new genus that we name Brandtodinium gen. nov. and the recombination of S. nutricula as B. nutricula comb. nov. %B Journal of Phycology %V 50 %P 388–399 %G eng %U http://dx.doi.org/10.1111/jpy.12174 %R 10.1111/jpy.12174