Putting the N in dinoflagellates

Dagenais-Bellefeuille, Steve; Morse, David

doi:10.3389/fmicb.2013.00369

Cited by 115 publications

(83 citation statements)

References 181 publications

(266 reference statements)

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“…The observed CO 2 -dependent changes in POC:PON ratios (Table 2) Previous studies on dinoflagellates, including A. fundyense, have shown up to 2-fold higher POC quotas under N limitation (Leong & Taguchi 2004, Fuentes-Grünewald et al 2012). In our study, A. fundyense displayed no such effect (Table 2; Eberlein et al 2014), which may be due to differences in culture conditions or species-and strain-specific regulation of enzymes involved in C storage under N limitation (Dagenais-Bellefeuille & Morse 2013). The few studies on combined effects of N limitation and elevated pCO 2 on marine phytoplankton do indeed show a high variety with respect to elemental quotas.…”

Section: Effects Of N Limitation and Elevated Pco 2 On Elemental Stoicontrasting

confidence: 52%

Interactive effects of ocean acidification and nitrogen limitation on two bloom-forming dinoflagellate species

Eberlein¹,

Waal²,

Brandenburg³

et al. 2016

Mar. Ecol. Prog. Ser.

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Global climate change involves an increase in oceanic CO 2 concentrations as well as thermal stratification of the water column, thereby reducing nutrient supply from deep to surface waters. Changes in inorganic carbon (C) or nitrogen (N) availability have been shown to affect marine primary production, yet little is known about their interactive effects. To test for these effects, we conducted continuous culture experiments under N limitation and exposed the bloomforming dinoflagellate species Scrippsiella trochoidea and Alexandrium fundyense (formerly A. tamarense) to CO 2 partial pressures (pCO 2 ) ranging between 250 and 1000 μatm. Ratios of particulate organic carbon (POC) to organic nitrogen (PON) were elevated under N limitation, but also showed a decreasing trend with increasing pCO 2 . PON production rates were highest and affinities for dissolved inorganic N were lowest under elevated pCO 2 , and our data thus demonstrate a CO 2 -dependent trade-off in N assimilation. In A. fundyense, quotas of paralytic shellfish poisoning toxins were lowered under N limitation, but the offset to those obtained under N-replete conditions became smaller with increasing pCO 2 . Consequently, cellular toxicity under N limitation was highest under elevated pCO 2 . All in all, our observations imply reduced N stress under elevated pCO 2 , which we attribute to a reallocation of energy from C to N assimilation as a consequence of lowered costs in C acquisition. Such interactive effects of ocean acidification and nutrient limitation may favor species with adjustable carbon concentrating mechanisms and have consequences for their competitive success in a future ocean.

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Section: Effects Of N Limitation and Elevated Pco 2 On Elemental Stoicontrasting

confidence: 52%

Interactive effects of ocean acidification and nitrogen limitation on two bloom-forming dinoflagellate species

Eberlein¹,

Waal²,

Brandenburg³

et al. 2016

Mar. Ecol. Prog. Ser.

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“…This proposition is supported by the fast increase in dinoflagellate abundance soon after the addition of dust (Tsagaraki et al, 2016, this SI). Dinoflagellates are known to be efficient removers of large amounts of bacterial biomass (Jeong et al, 2008;Dagenais-Bellefeuille and Morse, 2013).…”

Section: Methodsmentioning

confidence: 99%

Bacterial Growth and Mortality after Deposition of Saharan Dust and Mixed Aerosols in the Eastern Mediterranean Sea: A Mesocosm Experiment

et al. 2017

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The impact of viral lysis and grazing by flagellates on bacterioplankton production was assessed during a mesocosm experiment in the Eastern Mediterranean Sea, in response to Saharan dust (SD) vs. mixed aerosols (A) addition. The results highlight a positive effect on bacterial abundance, production and growth rate (∼1.2, ∼2.4, and ∼1.9 -fold higher than the controls) in both SD and A, which was also confirmed by the increased portion of high DNA content bacteria (up to 48% of the bacterial community). Lytic viral production and the portion of bacterial production lost due to viral lysis were lower in SD and A after dust addition than in the controls (0.33 ± 0.17 × 10 6 virus-like particles mL −1 h −1 and 6 ± 4%, respectively). Potential ingestion rate of bacteria by flagellates increased upon dust enrichment, but did not differ between mesocosms. Larger predators possibly down regulated flagellate abundance, and the calculated portion of bacterial production lost due to flagellate grazing was probably an artifact. Higher frequency of lysogenic cells in A compared to SD and the controls four days after dust addition may reflect faster phosphorus limitation in A, due to receiving less dissolved inorganic phosphorus and more dissolved inorganic nitrogen than SD.

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“…However, nitrate must first be reduced by nitrate reductase, a process using reduced ferredoxins (Fd) from the photosynthetic transport chain, or NAD(P)H (in non-photosynthetic organisms) (Dagenais-Bellefeuille and Morse, 2013). Ammonium is then assimilated via the glutamine synthetase/glutamine:2-oxoglutarate aminotransferase cycle (Pernice et al, 2012).…”

Section: Amino Acidsmentioning

confidence: 99%

Metabolite profiling of symbiont and host during thermal stress and bleaching in a model cnidarian-dinoflagellate symbiosis

Hillyer

Tumanov

Villas‐Bôas

et al. 2015

Journal of Experimental Biology

122

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Bleaching (dinoflagellate symbiont loss) is one of the greatest threats facing coral reefs. The functional cnidarian-dinoflagellate symbiosis, which forms coral reefs, is based on the bi-directional exchange of nutrients. During thermal stress this exchange breaks down; however, major gaps remain in our understanding of the roles of free metabolite pools in symbiosis and homeostasis. In this study we applied gas chromatography-mass spectrometry (GC-MS) to explore thermally induced changes in intracellular pools of amino and nonamino organic acids in each partner of the model sea anemone Aiptasia sp. and its dinoflagellate symbiont. Elevated temperatures (32°C for 6 days) resulted in symbiont photoinhibition and bleaching. Thermal stress induced distinct changes in the metabolite profiles of both partners, associated with alterations to central metabolism, oxidative state, cell structure, biosynthesis and signalling. Principally, we detected elevated pools of polyunsaturated fatty acids (PUFAs) in the symbiont, indicative of modifications to lipogenesis/lysis, membrane structure and nitrogen assimilation. In contrast, reductions of multiple PUFAs were detected in host pools, indicative of increased metabolism, peroxidation and/or reduced translocation of these groups. Accumulations of glycolysis intermediates were also observed in both partners, associated with photoinhibition and downstream reductions in carbohydrate metabolism. Correspondingly, we detected accumulations of amino acids and intermediate groups in both partners, with roles in gluconeogenesis and acclimation responses to oxidative stress. These data further our understanding of cellular responses to thermal stress in the symbiosis and generate hypotheses relating to the secondary roles of a number of compounds in homeostasis and heatstress resistance.

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Putting the N in dinoflagellates

Cited by 115 publications

References 181 publications

Interactive effects of ocean acidification and nitrogen limitation on two bloom-forming dinoflagellate species

Interactive effects of ocean acidification and nitrogen limitation on two bloom-forming dinoflagellate species

Bacterial Growth and Mortality after Deposition of Saharan Dust and Mixed Aerosols in the Eastern Mediterranean Sea: A Mesocosm Experiment

Metabolite profiling of symbiont and host during thermal stress and bleaching in a model cnidarian-dinoflagellate symbiosis

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