Interactions between a marine dinoflagellate (Alexandrium catenella) and a bacterial community utilizing riverine humic substances

Carlsson, Per; Edling, Hélène; Béchemin, Christian

doi:10.3354/ame016065

Cited by 51 publications

(35 citation statements)

References 55 publications

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“…A close relationship between cell based and Chl abased growth rates is not to be expected because of the varying Chl a cell content (Carlsson et al, 1998;Carignan et al, 2002). The only exception was the November 2004 bloom where balanced growth appears to have been achieved, and a possible cause for the highest growth rate ever reported for this organism (1.3 div d À1 ).…”

Section: Discussionmentioning

confidence: 94%

Contribution of several nitrogen sources to growth of Alexandrium catenella during blooms in Thau lagoon, southern France

et al. 2007

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A monitoring program with a weekly sampling frequency over a 15-month period indicates that urea concentrations above a certain threshold level may trigger the blooms of Alexandrium catenella in Thau lagoon. However, urea concentrations were also sometimes related to ammonium and dissolved organic nitrogen concentrations, indicating that the role of urea may not be a direct one. An original approach is used to assess the relative contribution of several nitrogen sources (nitrate, nitrite, ammonium, urea) to growth of A. catenella by comparing nitrogen uptake rates to nitrogen-based growth rates estimated from dilution experiments during four blooms over a 4-year period (2001)(2002)(2003)(2004) in Thau lagoon. Nitrate and nitrite contributed 0.1-14% and 0.1-5% respectively of growth requirements. Ammonium and urea were the main N sources fueling growth of A. catenella (30-100% and 2-59%, respectively). Indirect estimates indicated that an unidentified N source could also contribute significantly to growth at specific times. Concerning ammonium and urea uptake kinetics, half-saturation constants varied between 0.2 and 20 mgat N L À1 for ammonium and between 0.1 and 44 mgat N L À1 over the 4-year period, indicating that A. catenella can have a competitive advantage over other members of the phytoplankton even under low concentrations of ammonium and urea. However, the observed large changes in ammonium and urea uptake kinetics on a short time scale (days) during blooms preclude more precise estimates of those contributions to growth and require further investigation. #

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Section: Discussionmentioning

confidence: 94%

Contribution of several nitrogen sources to growth of Alexandrium catenella during blooms in Thau lagoon, southern France

et al. 2007

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“…Previous research demonstrates that in vivo fluorescence is proportional to cell densities of a variety of cultured phytoplankton species (Fogg & Thake 1987), including Aureococcus anophagefferens (Gobler & Cosper 1996). Cellular chlorophyll a (chl a) content and consequently in vivo fluorescence obviously vary among species, and also vary within a species depending upon nitrogen source and physiological status (Carlsson et al 1998). However, in vivo fluorescence is used here to generate biomass production rate con-…”

Section: Methodsmentioning

confidence: 99%

Speciation and concentrations of dissolved nitrogen as determinants of brown tide Aureococcus anophagefferens bloom initiation

Taylor

Gobler²,

Sañudo‐Wilhelmy³

2006

Mar. Ecol. Prog. Ser.

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Growth responses of the brown tide organism Aureococcus anophagefferens and 4 cooccurring microalgal species to varying concentrations of nitrate, ammonium, urea, and glutamate were assayed in laboratory experiments. Analogous to seasonal shifts in nutrient regimes in local bays, growth functional responses were used to predict relative species abundances in simulated communities supported by a reduced nitrogen source after cultivation on NO 3 -. Simulations were based on Monod kinetic parameters, lagged growth responses and threshold nutrient concentrations. Presented with NO 3 -only, rank order of biomass production was Thalassiosira pseudonana > Nannochloris atomus > Synechococcus bacillaris > Prorocentrum minimum > A. anophagefferens at all concentrations. In contrast, model communities offered NH 4 + or glutamate at most environmental concentrations (1 to 50 µM N) tended to be dominated by A. anophagefferens and P. minimum. Over environmental ranges of urea concentrations (1 to 50 µM N), T. pseudonana grew fastest, followed by A. anophagefferens. In field validation experiments, bay water with bloom concentrations of A. anophagefferens (10 5 cells ml -1) amended with equimolar (total N) nitrate-rich groundwater or reduced N-rich sediment porewater supported equal increases in total chlorophyll a through time. However, porewater selectively stimulated A. anophagefferens growth more than groundwater, and the converse was observed for cyanobacteria. Extrapolation of all experimental results to conditions in Long Island embayments suggests that phytoplankton communities supplied primarily with NO 3 -will be dominated by diatoms, such as T. pseudonana, and perhaps by chlorophytes and cyanobacteria like N. atomus and S. bacillaris. Conversely, phytoplankton communities primarily supplied with low-to-moderate concentrations of reduced N-species, NH 4 + , and dissolved organic nitrogen (DON) will be dominated by A. anophagefferens and, to a lesser extent, dinoflagellates like P. minimum. Our results are consistent with published field observations of A. anophagefferens bloom dynamics in Long Island estuaries.KEY WORDS: Aureococcus anophagefferens · Bottom-up control · Brown tide · Nitrogen uptake · Pelagophyceae · Submarine groundwater discharge Resale or republication not permitted without written consent of the publisher

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“…The availability of different forms of nitrogen and their relative rates of utilization are important factors determining phytoplankton productivity and succession (2,11). Recent studies in nutrient-enriched coastal areas indicate that while overall phytoplankton productivity may increase with availability of nitrogen, disproportionate increases in dissolved organic nitrogen (DON) versus inorganic nitrogen may significantly alter community composition and trigger harmful algal blooms (3,5).…”

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confidence: 99%

Dissolved Organic Nitrogen Hydrolysis Rates in Axenic Cultures of Aureococcus anophagefferens (Pelagophyceae): Comparison with Heterotrophic Bacteria

Berg

Repeta

LaRoche

2002

Appl Environ Microbiol

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Interactions between a marine dinoflagellate (Alexandrium catenella) and a bacterial community utilizing riverine humic substances

Cited by 51 publications

References 55 publications

Contribution of several nitrogen sources to growth of Alexandrium catenella during blooms in Thau lagoon, southern France

Contribution of several nitrogen sources to growth of Alexandrium catenella during blooms in Thau lagoon, southern France

Speciation and concentrations of dissolved nitrogen as determinants of brown tide Aureococcus anophagefferens bloom initiation

Dissolved Organic Nitrogen Hydrolysis Rates in Axenic Cultures of Aureococcus anophagefferens (Pelagophyceae): Comparison with Heterotrophic Bacteria

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