Bioavailability of inorganic and organic phosphorus compounds to natural assemblages of microorganisms m Hawaiian coastal waters

Björkman, Karin M.; Karl, D. M.

doi:10.3354/meps111265

Cited by 176 publications

(137 citation statements)

References 26 publications

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“…Friebele et al 1978, Berman 1983, Currie & Kalff 1984, Thingstad et al 1993, Bjorkman & Karl 1994, Dolan et al 1995). Yet, some reports point to a similar contribution of phytoplankton and bacteria (e.g.…”

Section: Discussionmentioning

confidence: 99%

Latitudinal variability in phosphate uptake in the Central Atlantic

Cañellas¹,

Agustı́²,

Duarte³

2000

Mar. Ecol. Prog. Ser.

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The role of P in regulating planktonic production in Atlantlc waters was assessed by the examination of the phosphate turnover time and uptake rate along a latitudinal transect across the Central Atlantic Ocean ( 2 f 0 N to 36"s). Phosphate uptake rates and the affinity for phosphate were higher for small (<0.8 pm) organisms, compared with those >0.8 pm. Phosphate uptake rates were relatively low, resulting in long phosphate turnover times (days), except in the surface waters south of 25"S, which were also characterized by the highest uptake rates and affinlty for phosphate, and the smallest total P pools observed along the transect The organisms were found to realize their maximal phosphate uptake rates at ambient phosphate concentrations, suggesting the adequacy of the P supply to support the requirements of organisms. These findings suggest that inorganic P was not Limiting community production in most of the Central Atlantic, except for the area south of 25" S, where P uptake could possibly be limited by P supply. The long turnover times generally observed in the Central Atlantic Ocean are in agreement with previous observations in oceanic systems elsewhere, suggesting that the observation that P is unllkely to be a limlting resource for planktonic growth can be extrapolated to most of the open ocean. The combined rate of P excretion from planktonic organisms and their microbial grazers as dissolved organic phosphorus (DOP) represented 75% of the total phosphate uptake. This DOP does not reach a sufficient accumulation as to drive an important downward flux of DOP, which represents a loss of only 9% of the P inputs into the biogenic layer. Hence, the high P uptake rate of the planktonic community in the Central Atlantic provides P in excess to support primary production, leading to a release as DOP, which appears to be rapidly recycled in the biogenic layer, thereby maintaining an adequate P supply to fuel primary production.

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Section: Discussionmentioning

confidence: 99%

Latitudinal variability in phosphate uptake in the Central Atlantic

Cañellas¹,

Agustı́²,

Duarte³

2000

Mar. Ecol. Prog. Ser.

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“…With respect to phosphorus limitation, experiments conducted with a marine Synechococcus indicated that the ambient inorganic phosphorus concentration in the surface ocean of 0.5 Â 10 À9 M would be sufficient to maintain a growth rate of 1.0 d À1 (Ikeya et al, 1997). It has been demonstrated that in addition to inorganic N and P, a variety of organically bound N (Wafar et al, 1995) and P (Bjorkman and Karl, 1994;Li, 1998) is present. For both Prochlorococcus and Synechococcus (Donald et al, 1997) there is evidence that growth is optimised by enriching the media with these organic compounds.…”

Section: àmentioning

confidence: 99%

Physiological responses of three species of marine pico-phytoplankton to ammonium, phosphate, iron and light limitation

Timmermans

Wagt

Veldhuis

et al. 2005

Journal of Sea Research

106

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Physiological responses of three species of marine pico-phytoplankton to ammonium, phosphate, iron and light limitation Timmermans, K.R.; Wagt, B. van der; Veldhuis, M.J.W.; Maatman, A.; de Baar, Henricus Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractExperiments were conducted with three species of marine pico-phytoplankton: Synechococcus sp. (CCMP 839), Pelagomonas calceolata (CCMP 1756) and Prasinomonas capsulatus (CCMP 1617) in order to collect physiological parameters for pico-phytoplankton to be utilised in Ocean Biogeochemical Climate Models. The main parameters to follow the effects of ammonium, phosphate, iron and light limitation were cell growth rates (A), half saturation constants for growth (K m ), N, P and Fe quota (per cell or per mol C), and photochemical quantum efficiency (F v /F m ).The nitrate and phosphate limitation experiments demonstrated that the small phytoplankton species could grow at low N and P concentrations. K m values were in the micro-molar (NH 4 + ) and sub-micro-molar (PO 4 3À ) range. N and P quota were in the femto-molar range per cell and varied from nutrient-deplete to nutrient-replete conditions. F v /F m values were only adversely affected at the lowest N and P concentrations in these experiments. In the Fe limitation experiments, it was shown that all three species were adversely affected only at extremely low Fe concentrations. Iron chelating agents had to be added to force the species in Fe limitation till ultimately growth stopped. K m values with respect to dissolved Fe were in the femto-molar range. Fe quota were in the low zepto-molar (10 À21 M) range per cell, and varied considerably from Fe limiting to Fe replete growth conditions. F v /F m values diminished only at the lowest iron concentrations. In the light limitation experiments, growth rates and photochemical quantum efficiencies were adversely affected only at irradiance levels below 10 Amol photons m À2 s À1 . These results indicate that the pico-phytoplankton species will hardly ever be completely stopped in their growth by NH 4 + , PO 4 3À, Fe or light (separately) under natural conditions. D

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“…Small nucleotides (e.g. Adenosintriphosphat) can be easily assimilated, whereas polymers (DNA, RNA) are characterized by long turnover times, resulting in accumulation of DOP in the water column (Thingstad et al, 1993;Björkman and Karl, 1994). Consequently, the biochemical composition of the individual DOP pool determines its bioavailability and is pivotal for its removal by bacteria and microalgae.…”

Section: Effect Of Different Nutrient Enrichment On Organic Matter Pamentioning

confidence: 99%

Production, partitioning and stoichiometry of organic matter under variable nutrient supply during mesocosm experiments in the tropical Pacific and Atlantic Ocean

et al. 2012

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Abstract. Oxygen-deficient waters in the ocean, generally referred to as oxygen minimum zones (OMZ), are expected to expand as a consequence of global climate change. Poor oxygenation is promoting microbial loss of inorganic nitrogen (N) and increasing release of sediment-bound phosphate (P) into the water column. These intermediate water masses, nutrient-loaded but with an N deficit relative to the canonical N : P Redfield ratio of 16 : 1, are transported via coastal upwelling into the euphotic zone. To test the impact of nutrient supply and nutrient stoichiometry on production, partitioning and elemental composition of dissolved (DOC, DON, DOP) and particulate (POC, PON, POP) organic matter, three nutrient enrichment experiments were conducted with natural microbial communities in shipboard mesocosms, during research cruises in the tropical waters of the southeast Pacific and the northeast Atlantic. Maximum accumulation of POC and PON was observed under high N supply conditions, indicating that primary production was controlled by N availability. The stoichiometry of microbial biomass was unaffected by nutrient N : P supply during exponential growth under nutrient saturation, while it was highly variable under conditions of nutrient limitation and closely correlated to the N : P supply ratio, although PON : POP of accumulated biomass generally exceeded the supply ratio. Microbial N : P composition was constrained by a general lower limit of 5 : 1. Channelling of assimilated P into DOP appears to be the mechanism responsible for the consistent offset of cellular stoichiometry relative to inorganic nutrient supply and nutrient drawdown, as DOP build-up was observed to intensify under decreasing N : P supply. Low nutrient N : P conditions in coastal upwelling areas overlying O 2 -deficient waters seem to represent a net source for DOP, which may stimulate growth of diazotrophic phytoplankton. These results demonstrate that microbial nutrient assimilation and partitioning of organic matter between the particulate and the dissolved phase are controlled by the N : P ratio of upwelled nutrients, implying substantial consequences for nutrient cycling and organic matter pools in the course of decreasing nutrient N : P stoichiometry.

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Bioavailability of inorganic and organic phosphorus compounds to natural assemblages of microorganisms m Hawaiian coastal waters

Cited by 176 publications

References 26 publications

Latitudinal variability in phosphate uptake in the Central Atlantic

Latitudinal variability in phosphate uptake in the Central Atlantic

Physiological responses of three species of marine pico-phytoplankton to ammonium, phosphate, iron and light limitation

Production, partitioning and stoichiometry of organic matter under variable nutrient supply during mesocosm experiments in the tropical Pacific and Atlantic Ocean

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