Light‐dependent Growth, Dark Survival, and Glucose Uptake by Cryptophytes Isolated From a Freshwater Chemocline

Gervais, Frank

doi:10.1111/j.0022-3646.1997.00018.x

Cited by 69 publications

(82 citation statements)

References 55 publications

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“…Cryptophytes and diatoms, the most abundant taxa in all experiments (Berger et al 2010;Lewandowska and Sommer 2010), showed the strongest response to warming. This is in agreement with physiological characteristics of these taxa (Gervais 1997;Litchman et al 2007). Both have high maximum growth and nutrient uptake rates and are able to outcompete other groups under nutrient replete conditions, which were the starting condition in all experiments.…”

Section: Discussionsupporting

confidence: 92%

Spring phenological responses of marine and freshwater plankton to changing temperature and light conditions

et al. 2012

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Shifts in the timing and magnitude of the spring plankton bloom in response to climate change have been observed across a wide range of aquatic systems. We used meta-analysis to investigate phenological responses of marine and freshwater plankton communities in mesocosms subjected to experimental manipulations of temperature and light intensity. Systems differed with respect to the dominant mesozooplankton (copepods in seawater and daphnids in freshwater). Higher water temperatures advanced the bloom timing of most functional plankton groups in both marine and freshwater systems. In contrast to timing, responses of bloom magnitudes were more variable among taxa and systems and were influenced by light intensity and trophic interactions. Increased light levels increased the magnitude of the spring peaks of most phytoplankton taxa and of total phytoplankton biomass. Intensified size-selective grazing of copepods in warming scenarios affected phytoplankton size structure and lowered intermediate (20-200 lm)-sized phytoplankton in marine systems. In contrast, plankton peak magnitudes in freshwater systems were unaffected by temperature, but decreased at lower light intensities, suggesting that filter feeding daphnids are sensitive to changes in algal carrying capacity as mediated by light supply. Our analysis confirms the general shift toward earlier blooms at increased temperature in both marine and freshwater systems and supports predictions that effects of climate change on plankton production will vary among sites, depending on resource limitation and species composition.

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Section: Discussionsupporting

confidence: 92%

Spring phenological responses of marine and freshwater plankton to changing temperature and light conditions

et al. 2012

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“…Gasol et al (1993) showed that C. phaseolus maintained a high population density in the metalimnion without any sign of bacterial ingestion. Gervais (1997) also showed that several species of Cryptomonas could grow without bacterial ingestion in lab-oratory cultures. Thus, phagotrophy by Cryptomonas seems not for acquisition of some substance essential to their growth.…”

Section: Discussionmentioning

confidence: 95%

“…Tranvik et al (1989) 1 Corresponding author. suggested that phagotrophy in Cryptomonas is induced by low light conditions but concluded that bacteria are not an important energy source for Cryptomonas because their specific ingestion rate for bacteria was very limited even under low light. In other studies, Cryptomonas did not show any indication of phagotrophy (Sanders et al 1989;Gasol et al 1993;Gervais 1997). It should be noted, however, that these studies examined phagotrophy under laboratory conditions, where light intensity was controlled artificially or in situ at an unspecific time during the day.…”

mentioning

confidence: 81%

Diel changes in phagotrophy by Cryptomonas in Lake Biwa

Urabe¹,

Gurung²,

Yoshida³

et al. 2000

Limnology & Oceanography

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Diel changes in bacterial ingestion by a mixotrophic flagellate, Cryptomonas sp., and heterotrophic nanoflagellates (HNF) were examined in situ at 4-h intervals for 2 d in the epilimnion and metalimnion of Lake Biwa using bacteria-sized fluorescent microspheres as a tracer food. Clearance rates of HNF for the microspheres ranged between 1.3 and 4.5 nl cell Ϫ1 h Ϫ1 , but the average rate did not differ between day and night. In contrast, clear diel changes were observed in the clearance rate of Cryptomonas sp. in the epilimnion from Ͻ0.5 nl cell Ϫ1 h Ϫ1 at midnight to Ͼ3 nl cell Ϫ1 h Ϫ1 at noon. In the metalimnion where light intensity was lower, however, the clearance rate of Cryptomonas sp. was always Ͻ0.5 nl cell Ϫ1 h Ϫ1 through the study period. Thus, bacterial ingestion of Cryptomonas sp. is not to acquire supplementary energy or carbon at low phototrophic activities. During the study period, both inorganic phosphorus and nitrogen concentrations were less than or close to the detection limits (10 nM P and 1 M N) in the epilimnion, but much higher in the metalimnion. The results strongly support the idea that Cryptomonas sp. utilizes N and P from bacteria as substitutable nutrients when photosynthesis takes place under conditions of nutrient depletion. To assess the grazing effect of mixotrophic algae on bacterial populations, it is essential to consider diel changes in their phagotrophic mode of nutrition that are induced by light regime and nutrient concentrations in ambient water.

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“…According to the recommendations of Gervais (1997) to cultivate cryptophytes, no boron was added and the N source was ammonium chloride rather than sodium nitrate. This light intensity does not limit the growth of Cryptomonas spp.…”

Section: Cultivationmentioning

confidence: 99%

“…This light intensity does not limit the growth of Cryptomonas spp. (Gervais, 1997). Continuous light conditions were chosen to reduce possible diurnal effects on cell P pools.…”

Section: Cultivationmentioning

confidence: 99%

Strict stoichiometric homeostasis of Cryptomonas pyrenoidifera (Cryptophyceae) in relation to N:P supply ratios

2016

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A common freshwater cryptophyte, Cryptomonas pyrenoidifera, was cultivated in batch-cultures to analyze intraspecific variation in elemental stoichiometry along a broad gradient of pulsed phosphorus (P) enrichment during the early acclimation period and to determine the immediate homeostatic capacity of the nitrogen-to-phosphorus (N:P) ratio of this alga when nutrients are at saturating levels. Experimental results revealed that nitrogen (N) and P cell quotas significantly increased with increasing P concentration. However, despite the wide range of N:P ratios in the medium, C. pyrenoidifera N:P ratios were highly stable at higher P-level treatments, indicating a highly conservative behavior and suggesting strict elemental homeostasis when nutrients are at saturating levels. The strictly homeostatic N:P ratio appears to be attributable to their high potential for a fast luxury consumption of both N and P after a brief and intense episode of increased resource availability and to physiological limits on their nutrient storage capacity. Most importantly, the N:P biomass ratio at nutrient saturating levels converged around 11:1, which was the observed ratio of maximum internal cell quotas for N and P (i.e., Q max , N :Q max , P ) under the prevailing experimental conditions. This value is particularly informative for C. pyrenoidifera because it represents cell storage quotients and may be a taxon-specific evolutionary optimum, providing a reference point to infer the grade of nutrient-limitation. The experimental data give ranges of variation in C. pyrenoidifera elemental composition permitting, among others, proper parameterization of cryptophyte stoichiometry models.

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Light‐dependent Growth, Dark Survival, and Glucose Uptake by Cryptophytes Isolated From a Freshwater Chemocline

Cited by 69 publications

References 55 publications

Spring phenological responses of marine and freshwater plankton to changing temperature and light conditions

Spring phenological responses of marine and freshwater plankton to changing temperature and light conditions

Diel changes in phagotrophy by Cryptomonas in Lake Biwa

Strict stoichiometric homeostasis of Cryptomonas pyrenoidifera (Cryptophyceae) in relation to N:P supply ratios

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