Preparation of 14C-labeled algal samples for liquid scintillation counting

Niemi, Maarit; Kuparinen, Jorma; Uusi-Rauva, A.; Korhonen, Kaija

doi:10.1007/bf00006747

Cited by 56 publications

(34 citation statements)

References 17 publications

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“…Filters were rinsed twice with 0.2 pm filtered lake water, placed in scintillation vials and 100 p1 concentrated HCl was added to remove any remaining inorganic 14C. Before rinsing the filters, 4 ml of the filtrate was transferred into scintillation vials, acidified with 100 p1 concentrated HC1 and left open for 24 h (Niemi et al 1983). Filters and filtrates were stored at 4OC until further analysis at the Institute of Ecology, University of Vienna.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of phyto- and bacterioplankton in a high Arctic lake on Franz Joseph Land archipelago

Panzenböck¹,

Möbes-Hansen²,

Albert³

et al. 2000

Aquat. Microb. Ecol.

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Pelagic food web processes with focus on phyto-and bacterioplankton dynamics were followed in a high Arctic lake on Ziegler Island, Franz Joseph Land archipelago, during July and August 1996. The oligotrophlc, permanently ice-covered lake is characterized by a rather short pelagic food web with rotifers representing the highest trophic level. Phytoplankton biomass and net primary production averaging 1.8 pg chl a 1-' and 22 pg C 1-' d-', respectively, decreased dunng the investigation period. Photosynthetic extracellular release (P,,) corrected for bacterial uptake was high and contributed between 31 % (July) and 96% (August) of total primary production. The abundance of bacteria (9.3 to 17.3 X 10' ml-l) and flagellates (7.8 to 17.3 X 10' ml-l) varied within a narrow range. Bacterioplankton production ranging from 1.2 to 3.9 pg C 1-' d-' and bacterial growth rates (0.1 to 0.3 d-') increased with increasing % P,,, indicating that algal exudates are the major carbon source for bacterioplankton. Bacterial carbon demand (assuming a 50% growth efficiency) amounted to 19% of gross pelagic primary production (P,,,, + P,,) and 31 % of P,, during the investigation period. Evidence was found that bacterioplankton metabolism responds quickly to slight increases in temperature (1.2 to 2.0°C) with increased growth. Overall, production rates of phyto-and bacterioplankton in this high Arctic lake are simdar to other Arctic lakes studied thus far, and the food web structure is even simpler than in most lakes at similar latitudes.

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Section: Methodsmentioning

confidence: 99%

Dynamics of phyto- and bacterioplankton in a high Arctic lake on Franz Joseph Land archipelago

Panzenböck¹,

Möbes-Hansen²,

Albert³

et al. 2000

Aquat. Microb. Ecol.

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“…Primary productivity was measured with the 14C method (Steemann Nielsen 1952, the modification presented by Niemi et al 1983) as apparent net productivity (particulate + dissolved organic I4C), after incubations of 20 m1 samples with 2 pCi addition of NaHI4CO3 (CFA.3, Amersham International). Incubation time was ca 2 h, duplicates with a dark blank were incubated for each sample, and incubations were terminated by the addition of 38% formaldehyde (100 p1 per 20 m1 sample).…”

Section: Methodsmentioning

confidence: 99%

Urea uptake kinetics of a midsummer planktonic community on the SW coast of Finland

Tamminen¹,

Irmisch²

1996

Mar. Ecol. Prog. Ser.

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Urea uptake of the plankton~c community was studied in a serles of experiments on the SW coast of Finland, the Baltic Sea, in midsummer. Uptake was measured with '"-urea incubatlons, where respired I4CO2 was found to represent 98 to 99% of total uptake. Uptake kinetics were characterized by high affin~ty for urea (0.97 to 1.84 pg N I-'), fast turnover rates (29 to 99% h -' ) and model--ate maximum uptake velocit~es (0.52 to 1.31 pg N I-' h-'). Light stimulated urea uptake; parallel dark incubations usually yielded uptakes 60 to 80% of those in the light. No surge uptake of urea was observed, as all kinetic parameters remained constant in a short-term time series experiment. Sizefractlonat~on studies and light/dark incubatlons indicated that phytoplankton dominated urea uptake. The time course of urea depletion in an ennchment experiment follo\'ved the die1 pnmary production pattern, and the depletion rate was of the same order as the ammonium depletion rate lnorganic nitrogen additions (ammonium, nitrate) did not produce immediate Inhibitions of urea uptake, but with a time lag of 1 night, ammonium inhibition was observed. Phosphate addition stimulated urea uptake. Evidence on stimulated bacterioplankton uptake of urea was found the next night after organic carbon source addition. Alternative nitrogen sources (NO,. NH4, urea) were utihzed mainly according to their availability. Urea proved to be an important nitrogen source for phytoplankton during the regenerated phase of plankton succession.

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“…Net primary productivity (particulate plus dissolved fraction) was measured by acidifying a 4-ml subsample in glass scintillation vials with 100 ~1 of 1 N HCl. The vials were allowed to stand open (without bubbling) for 24 h to remove any inorganic 14C (Niemi et al 1983). After this, 7 ml of PCS cocktail (Amersham) was added to the subsamples.…”

Section: Methodsmentioning

confidence: 99%

Nutrient limitation and grazing control of the Baltic plankton community during annual succession

Kivi¹,

Kaitala²,

Kuosa³

et al. 1993

Limnology & Oceanography

152

104

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Nutrient limitationand grazing control of the planktonic community were studied in the northern Baltic Sea off the SW coast of Finland during the phytoplankton growth season of 1985. In situ experiments based on a 23 factorial design were performed in mesocosm enclosures on 10 occasions. The manipulations used included phosphorus (PO,? ) and nitrogen (NH,+ ) additions and the removal of metazooplankton by 1 OO+m prefiltration.In each experiment, the responses of phytoplankton, bacterioplankton, heterotrophic nanoflagellates, and protozooplankton were followed for 2 d. Orthogonal multiple regression analysis was used to reveal which manipulations had statistically significant effects. Nitrogen was found to be the basic limiting nutrient for phytoplankton throughout the productive season. During early summer, only the combined addition of P and N evoked a clear increase in the growth of phytoplankton.In general, bacterial productivity was not highly affected by the manipulations. In summer the removal of metazooplankton caused a rapid increase in the amount of protozooplankton in the units with loo-pm prefiltration or prefiltration combined with N addition. In the absence of metazooplankton, the nutrient-induced increase in primary productivity was channeled to protozooplankton, whose growth in the units where metazooplankton was present was severely limited by food competition or by direct metazooplankton grazing.

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Preparation of 14C-labeled algal samples for liquid scintillation counting

Cited by 56 publications

References 17 publications

Dynamics of phyto- and bacterioplankton in a high Arctic lake on Franz Joseph Land archipelago

Dynamics of phyto- and bacterioplankton in a high Arctic lake on Franz Joseph Land archipelago

Urea uptake kinetics of a midsummer planktonic community on the SW coast of Finland

Nutrient limitation and grazing control of the Baltic plankton community during annual succession

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