Urea uptake by phytoplankton at various stages of nutrient depletion

Horrigan, SG; McCarthy, James J.

doi:10.1093/plankt/3.3.403

Cited by 43 publications

(17 citation statements)

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“…Glibert ) and thus we were unable to detect short term variations in uptake rate. Enhanced uptake of NHZ and urea by NO;-sufficient phytoplankton has been reported (Horrigan & McCarthy 1981, Parslow et al 1984b) but in the light of the slower long term rates of NH; and urea uptake, relative to NO; uptake in the frontal station, it appears unlikely that such a process occurred on time scales shorter than our measurements. On long time scales, changes in uptake rate due to die1 periodicity were evident in our results.…”

Section: Simultaneous Uptake Of Nitrogen Compoundsmentioning

confidence: 41%

“…Dugdale & Goering 1967, McCarthy et al 1977. Experiments using laboratory cultures of phytoplankton have demonstrated that the preconditioning nitrogen substrate affects the response of phytoplankton to the additions of different forms of nitrogen (Horrigan & McCarthy 1981, Dortch & Conway 1984. Additionally, in nitrogen-starved phytoplankton, the ability to take up nitrate may be lost and must be induced (Dortch et al 1982, review by Collos 1983, Parslow et al 1984b).…”

Section: Introductionmentioning

confidence: 99%

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Time course of uptake of inorganic and organic nitrogen by phytoplankton in the Strait of Georgia: comparison of frontal and stratified communities

Price¹,

Cochlan²,

Harrison³

1985

Mar. Ecol. Prog. Ser.

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In both frontal and stratified water of the Strait of Georgia, changes in dissolved nitrogen concentrations provided evidence for the simultaneous uptake of ammonium, nitrate and urea by a summer phytoplankton community. Chlorophyll a specific uptake rates of ammonium and urea were ca 2 and 2.4 times greater in stratified water than in frontal water, whereas chlorophyll a specific nitrate uptake rates were ca 1.6 times greater in frontal water. Ammonium and urea regeneration rates, calculated using a mass balance approach, were similar in frontal water, but urea regeneration rates were 2 to 5 times greater in the stratified water during the first 12 h of the experiment. Increases in particulate nitrogen could not be accounted for by corresponding decreases in total concentration of dissolved inorganic nitrogen and urea, or by 15N accumulation in the particulates. In frontal water the change in total dissolved inorganic nitrogen and urea consistently overestimated the change in particulate nitrogen, and in stratified water the change in total dissolved inorganic nitrogen and urea consistently underestimated the change in particulate nitrogen. These data suggest that the plankton community In frontal water was losing nitrogen in the form of dissolved organic nitrogen. By contrast, the plankton community in stratified water took up nitrogen compounds which were not measured as part of the total dissolved inorganic and urea nitrogen, but were most likely dissolved organic nitrogen compounds. Results stress the importance of determining uptake rates of all 3 nitrogen substrates (NHfi, N O and urea) using 15N isotopes and by simultaneously measuring the change in concentration of these compounds throughout the incubation period.

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Section: Simultaneous Uptake Of Nitrogen Compoundsmentioning

confidence: 41%

Section: Introductionmentioning

confidence: 99%

Time course of uptake of inorganic and organic nitrogen by phytoplankton in the Strait of Georgia: comparison of frontal and stratified communities

Price¹,

Cochlan²,

Harrison³

1985

Mar. Ecol. Prog. Ser.

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“…A time lag may exist between the assimilation of the organic molecule and the excretion of metabolites (Iturriaga and Zsolnay, 1981). For example, Horrigan and McCarthy (1981) recently observed preferential incorporation of nitrogen over carbon during 14C labelled urea uptake of phytoplankton cultures. This type of selectivity for a particular element of an organic molecule may also occur in substrate assimilation by heterotrophs.…”

Section: Discussionmentioning

confidence: 99%

Ammonium regeneration: its contribution to phytoplankton nitrogen requirements in a eutrophic environment

LaRoche

1983

Mar. Biol.

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Ammonium regeneration, nutrient uptake, bacterial activity and primary production were measured from March to August 1980 in Bedford Basin, Nova Scotia, Canada, a eutrophic environment. Rates of regeneration and nutrient uptake were determined using 15N isotope dilution and tracer methodology. Although primary production, nutrient uptake and ammonium regeneration were significantly intercorrelated, no relationship was detected between these parameters and heterotrophic activity. The average contribution of ammonium to total nitrogen (ammonium + nitrate) uptake was similar in the spring and in the summer (approximately 60%). On a seasonal average basis, 36% of the phytoplankton ammonium uptake could be supplied by rapid remineralization processes. In spite of the high average contribution of NH4 regeneration to phytoplankton ammonia uptake, there is indirect evidence suggesting that other NH4 sources may occasionally be important.

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“…Although urea uptake in macroalgae is not well documented, the presence of inorganic N (e.g. NO 3 -, NH 4 + ) in the culture medium can inhibit urea uptake rates in phytoplankton (Horrigan & McCarthy 1982, Antia et al 1991.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen ecophysiology of intertidal seaweeds from New Zealand: N uptake, storage and utilisation in relation to shore position and season

Phillips¹,

Hurd²

2003

Mar. Ecol. Prog. Ser.

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Urea uptake by phytoplankton at various stages of nutrient depletion

Cited by 43 publications

References 0 publications

Time course of uptake of inorganic and organic nitrogen by phytoplankton in the Strait of Georgia: comparison of frontal and stratified communities

Time course of uptake of inorganic and organic nitrogen by phytoplankton in the Strait of Georgia: comparison of frontal and stratified communities

Ammonium regeneration: its contribution to phytoplankton nitrogen requirements in a eutrophic environment

Nitrogen ecophysiology of intertidal seaweeds from New Zealand: N uptake, storage and utilisation in relation to shore position and season

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