Net growth of the bloom-forming dinoflagellate Heterocapsa triquetra and pH: why turbulence matters

Havskum, Harry; Hansen, Per Juel

doi:10.3354/ame042055

Cited by 21 publications

(16 citation statements)

References 29 publications

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“…With the same setup and similar experimental design and turbulence conditions, different species-specific responses have been observed: while the net growth rates of Oxyrrhis marina (Havskum, 2003) and of Ceratium tripos (Havskum et al, 2005) decreased, the one of Fragilidium subglobosum was not affected (Havskum et al, 2005) and that of Heterocapsa triquetra was favoured (Havskum and Hansen, 2006). In this last study, those authors suggested that turbulence facilitated gas exchange and avoided excessive pH increase in the experimental vessels allowing higher cell numbers than in the still flasks.…”

Section: Discussionmentioning

confidence: 84%

“…The available data indicate that the direct effect of turbulence is species-specific and dependent on the experimental conditions (Berdalet and Estrada, 1993;Berdalet et al, 2007), although direct comparison between studies is not straightforward (Peters and Marrasé, 2000). Some studies have found positive (or indifferent) biological responses (Berdalet and Estrada, 1993;Havskum et al, 2005;Havskum and Hansen, 2006). Many others reported negative effects that, in general, point to the interference of small-scale turbulence with cell division and life cycle processes (including migration) (e.g., Berdalet, 1992;Pollingher and Zemel, 1981;Yeung and Wong, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Modulation of ecdysal cyst and toxin dynamics of two <i>Alexandrium</i> (Dinophyceae) species under small-scale turbulence

et al. 2007

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Abstract. Some dinoflagellate species have shown different physiological responses to certain turbulent conditions. Here we investigate how two levels of turbulent kinetic energy dissipation rates (ε = 0.4 and 27 cm 2 s −3 ) affect the PSP toxins and ecdysal cyst dynamics of two bloom forming species, Alexandrium minutum and A. catenella. The most striking responses were observed at the high ε generated by an orbital shaker. In the cultures of the two species shaken for more than 4 days, the cellular GTX(1+4) toxin contents were significantly lower than in the still control cultures. In A. minutum this trend was also observed in the C(1+2) toxin content. For the two species, inhibition of ecdysal cyst production occurred during the period of exposure of the cultures to stirring (4 or more days) at any time during their growth curve. Recovery of cyst abundances was always observed when turbulence stopped. When shaking persisted for more than 4 days, the net growth rate significantly decreased in A. minutum (from 0.25±0.01 day −1 to 0.19±0.02 day −1 ) and the final cell numbers were lower (ca. 55.4%) than in the still control cultures. In A. catenella, the net growth rate was not markedly modified by turbulence although under long exposure to shaking, the cultures entered earlier in the stationary phase and the final cell numbers were significantly lower (ca. 23%) than in the control flasks.The described responses were not observed in the experiments performed at the low turbulence intensities with an orbital grid system, where the population development was favoured. In those conditions, cells appeared to escape from the zone of the influence of the grids and concentrated in calmer thin layers either at the top or at the bottom of the containers.This ecophysiological study provides new evidences about the sensitivity to high levels of small-scale turbulence by two life cycle related processes, toxin production and encystment, in dinoflagellates. This can contribute to the understanding of the dynamics of those organisms in nature.

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Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Modulation of ecdysal cyst and toxin dynamics of two <i>Alexandrium</i> (Dinophyceae) species under small-scale turbulence

et al. 2007

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“…It could be possible that a raise in pH may have occurred in the unshaken flasks, associated with the development of the microplanktonic communities. Havskum & Hansen (2006) noted that moderate turbulence could palliate pH-related growth limitations in high-density cultures of Heterocapsa sp. by facilitating gas exchange.…”

Section: Discussionmentioning

confidence: 99%

Small-scale turbulence can reduce parasite infectivity to dinoflagellates

Llaveria¹,

Garcés²,

Ross³

et al. 2010

Mar. Ecol. Prog. Ser.

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“…R 2 = coefficient of determination surroundings and the air-water CO 2 flux, which is assumed to ensure a relatively stable pH (about 8.2, Skirrow 1975) in the marine environment, despite high photosynthetic rates. Wind and turbulence enhance both these processes (Havskum & Hansen 2006). On windy days the water is thus rapidly exchanged with the surrounding water and the air-water flux is high, causing pH to decrease.…”

Section: Level and Variability Of Ph In Shallow-water Habitatsmentioning

confidence: 99%

High pH in shallow-water macroalgal habitats

Middelboe

Hansen²

2007

Mar. Ecol. Prog. Ser.

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104

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The aim of this study was to evaluate seasonal and diurnal variability in pH and inorganic carbon in shallow-water macroalgal habitats and to evaluate the importance of high pH for macroalgal photosynthesis. Seasonal variations in pH, oxygen saturation and inorganic carbon concentration were measured at an exposed and a sheltered shallow-water (0 to 1 m) macroalgal habitat. Daytime pH was significantly higher in spring, summer and autumn than in winter at both study sites. Diurnal measurements at the most exposed site showed significantly higher pH during the day than during the night. The diurnal variations were largest in shallow water and decreased with increasing water depth. High pH resulted in periodically low concentrations of available inorganic carbon in summer (as low as 1.3 mmol [CO 2 + HCO 3 -] l -1). Photosynthesis as a function of inorganic carbon concentrations was measured at pH 8 and 9.3 for 4 common macroalgal species (Fucus vesiculosus, F. serratus, Ceramium rubrum, Ulva sp.). Photosynthesis in these species was not limited by natural concentrations of inorganic carbon, but maximum photosynthesis and inorganic carbon concentrations at saturation were lower when measured at pH 9.3 than at pH 8. Our results suggest that pH is higher in natural shallow-water habitats than previously thought, and that high pH has a direct effect on photosynthesis that cannot be accounted for by low availability of inorganic carbon. KEY WORDS: pH · Seasonal variations · Diurnal variations · Macroalgae · PhotosynthesisResale or republication not permitted without written consent of the publisher

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Net growth of the bloom-forming dinoflagellate Heterocapsa triquetra and pH: why turbulence matters

Cited by 21 publications

References 29 publications

Modulation of ecdysal cyst and toxin dynamics of two <i>Alexandrium</i> (Dinophyceae) species under small-scale turbulence

Modulation of ecdysal cyst and toxin dynamics of two <i>Alexandrium</i> (Dinophyceae) species under small-scale turbulence

Small-scale turbulence can reduce parasite infectivity to dinoflagellates

High pH in shallow-water macroalgal habitats

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Net growth of the bloom-forming dinoflagellate Heterocapsa triquetra and pH: why turbulence matters

Cited by 21 publications

References 29 publications

Modulation of ecdysal cyst and toxin dynamics of two &lt;i&gt;Alexandrium&lt;/i&gt; (Dinophyceae) species under small-scale turbulence

Modulation of ecdysal cyst and toxin dynamics of two &lt;i&gt;Alexandrium&lt;/i&gt; (Dinophyceae) species under small-scale turbulence

Small-scale turbulence can reduce parasite infectivity to dinoflagellates

High pH in shallow-water macroalgal habitats

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Product

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Modulation of ecdysal cyst and toxin dynamics of two <i>Alexandrium</i> (Dinophyceae) species under small-scale turbulence

Modulation of ecdysal cyst and toxin dynamics of two <i>Alexandrium</i> (Dinophyceae) species under small-scale turbulence