Regulation of Bacterioplankton Production and Cell Volume in a Eutrophic Estuary

Bjørnsen, Peter Koefoed; Riemann, Bo; Pock-Steen, Jan; Nielsen, Torkel Gissel; Horsted, Steen Jesper

doi:10.1128/aem.55.6.1512-1518.1989

Cited by 34 publications

(7 citation statements)

References 38 publications

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“…While the biomass of the initial C. grucilis bloom was only moderately high, algal exudate from this peak may have facilitated the following large bacterial bloom (Bjornsen et al 1989;Sander and Kalff 1993). In turn, release of nutrients from the bacterial peak crash may have enabled the subsequent, large algal bloom.…”

Section: Discussionmentioning

confidence: 98%

Disinfection, Microbial Community Establishment and Shrimp Production in a Prototype Biosecure Pond

Bratvold

Browdy

1999

J World Aquaculture Soc

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Plankton community establishment and shrimp production in a prototype biosecure pond were compared to three control ponds. The biosecure pond was enclosed and intake water was disinfected, while control ponds were neither enclosed nor disinfected. All ponds were managed with no water exchange and stocked with 100 postlarvaelm*, Litopenaeus vannarnei. Residual oxidant concentrations in the biosecure pond dropped rapidly after cessation of chlorinated water addition. This was followed by a sharp increase in water column bacterial abundance, after which the pond was fertilized and inoculated with cultured Chaetocerous gracilis. After crash of the initial C. gracilis bloom in the biosecure pond, this species was not observed again. Following initial large fluctuations in biosecure pond bacterial abundance, phytoplankton biomass, oxygen consumption and nitrification rates, these parameters appeared to stabilize at levels similar to the control ponds. Early season compositional differences in phytoplankton, zooplankton, and bacterial communities were observed. No differences were seen in late-season phytoplankton and bacteria; however, zooplankton biomass tended to be lower in the biosecure pond than in the control ponds throughout the season. Shrimp production in all ponds was greater than 9,000 kg/ha. Production in the single biosecure pond was not a significant outlier compared to production in the triplicate control ponds.

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Section: Discussionmentioning

confidence: 98%

Disinfection, Microbial Community Establishment and Shrimp Production in a Prototype Biosecure Pond

Bratvold

Browdy

1999

J World Aquaculture Soc

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“…Aroclor 1260 had an impact particularly evident on the heterotrophic component, determining a reduction of bacterial abundance (up to 80%) within 24 h. The relationship between bacterial production and cell size has been repeatedly investigated (Björnsen et al, 1989;Bird and Kalff, 1993). Recently, Servais et al (1999) and Bernard et al (2000) have shown that certain size classes have higher growth rates than others, thus, contributing to a larger fraction of bacterial C production.…”

Section: Discussionmentioning

confidence: 99%

Impact of heavy metals and PCBs on marine picoplankton

Caroppo¹,

Stabili²,

Aresta³

et al. 2006

Environmental Toxicology

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Synergistic/antagonistic effects of multiple contaminants in marine environments are almost completely unexplored. In the present study, we investigated the effects of heavy metals (Zn and Pb) and PCBs on picoplankton abundance, biomass, cell size distribution, and bacterial C production. Natural picoplankton assemblages were exposed to heavy metals (Zn or Pb), organic contaminants (PCBs, Aroclor 1260), and to a mixture of different contaminants. The results of the present study indicate that Zn addition stimulated heterotrophic growth, whereas Pb has a negative impact on heterotrophic picoplankton, particularly significant in the first 24 h. Heavy metals had no effects on the autotrophic component. The addition of Aroclor 1260 had a significant impact on abundance, biomass, and cell size of autotrophic and heterotrophic picoplankton, and reduced significantly bacterial secondary production. Three weeks after PCB treatment, heterotrophic bacteria displayed a clear resilience, both in terms of abundance and biomass, reaching values comparable to those of the controls, but not in terms of bacterial C production. Our results indicate that picoplankton can be sensitive indicators of impact determined by heavy metals and PCBs in coastal marine systems.

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“…7A). This is not surprising as cell activities are systematically related to cell size (Bjornsen et al 1989).…”

Section: Applicationmentioning

confidence: 93%

Improved methodology to measure taxon‐specific phosphate uptake in live and unfiltered samples

Talarmin

Duhamel

Catala

et al. 2011

Limnology & Ocean Methods

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Microorganisms play a major role in the marine phosphate biogeochemical cycle but the relative contribution of picoplanktonic groups is not well understood. Previous studies have shown that combining uptake measurements of radiolabeled dissolved inorganic phosphate (P-i) substrate with cell sorting by flow cytometry is a powerful tool for the assessment of P-i fluxes at the cell-specific level. Nevertheless, using P-33 to trace P-i uptake, we show that treatments involving fixation and filtration of the sorted groups (i.e., heterotrophic prokaryotes, Synechococcus and piconanophytoeukaryotes) induce leakage of radioactive P-i (up to 50% of the signal), resulting in a sizeable underestimation of the taxon-specific P-i uptake. We suggest an alternative protocol, which significantly reduces this bias. Using this optimized protocol, the samples were treated with an excess of nonradioactive P-i to stop the incubation and sorted fractions were directly collected in microtubes for radioactivity counting, avoiding signal loss due to filtration. Sorted groups were strongly and differently impacted by fixation (0.5% PFA), with the exception of Synechococcus cells, which showed once a 10% lower signal in samples treated with the previously used protocols compared with samples treated with ours. Based on the integrity of the live sorted cells, our improved protocol provides reproducible and accurate estimations of the taxon-specific P-i uptake (<= 11% variation on cellular uptake rates, sd/average, n = 69). It was successfully applied to P-depleted oligotrophic seawater samples from the Mediterranean and will allow a comparison of taxon-specific uptake rates between sites

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Regulation of Bacterioplankton Production and Cell Volume in a Eutrophic Estuary

Cited by 34 publications

References 38 publications

Disinfection, Microbial Community Establishment and Shrimp Production in a Prototype Biosecure Pond

Disinfection, Microbial Community Establishment and Shrimp Production in a Prototype Biosecure Pond

Impact of heavy metals and PCBs on marine picoplankton

Improved methodology to measure taxon‐specific phosphate uptake in live and unfiltered samples

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