Short- and long-term effects of ammonium on photodependent nitrogen fixation in wetland rice fields of Spain

Valiente, Eduardo Fernández; Quesada, Antonio; Prósperi, C.; Nieva, M.; Leganés, Francisco; Ucha, A.

doi:10.1007/s003740050257

Cited by 12 publications

(4 citation statements)

References 11 publications

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“…N 2 fixation in Twin Cays' dwarf mats was inhibited when NH 4 + concentrations exceeded 0.5 mM (data not shown). This value falls within the inhibitory range of 50 to 500 µM observed in other studies (Capone 1988, Valiente et al 1997. Transition and fringe fixation rates varied independently of porewater NH 4 + concentrations which were consistently less than 20 µM, and thus not likely the primary factor controlling N 2 fixation in those habitats.…”

Section: Chemical Environmental Controlssupporting

confidence: 56%

Seasonal patterns of nitrogen fixation and denitrification in oceanic mangrove habitats

Lee¹,

Joye²

2006

Mar. Ecol. Prog. Ser.

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Mangrove peat soils are home to a variety of microbial communities that may play a vital role in system-level elemental cycling. We examined rates of nitrogen fixation and denitrification in benthic microbial mats on Twin Cays, Belize, a pair of oceanic mangrove islands. A tree-height gradient across the islands created distinct habitats for benthic microbes. Seawater flushing of the benthos and tree height decreased landward from tall, dense trees on the island fringe through a transition zone of high elevation and intermediate tree heights. In the center of the islands, microbial mats with dense communities of cyanobacteria and purple sulfur bacteria covered the benthic surface of shallow ponds and around dwarf trees. Wet-dry seasonality, tidal cycles and elevation controlled the extent of mat exposure to desiccation and UV radiation. Nitrogen fixation was controlled primarily by the sensitivity of nitrogenase to oxygen inhibition, whereas denitrification was limited by oxidant (nitrate) availability. Diel patterns of nitrogen fixation varied with the type of cyanobacteria dominant in each mat. Dissolved inorganic nitrogen concentration influenced both nitrogen fixation and denitrification rates. Redox conditions contributed to variability in mat nitrogen fixation and denitrification response to nutrient addition, while dissolved organic carbon did not. Microbial mat nitrogen cycling likely contributes to the nutrient (nitrogen and phosphorus) limitation patterns observed in the mangrove trees; in dwarf habitats, mats serve as a source of nitrogen via nitrogen fixation, while in fringe and transition habitats, mats compete with the trees for nitrogen via denitrification.

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Section: Chemical Environmental Controlssupporting

confidence: 56%

Seasonal patterns of nitrogen fixation and denitrification in oceanic mangrove habitats

Lee¹,

Joye²

2006

Mar. Ecol. Prog. Ser.

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“…2. The increase in ammonium concentration inhibits both nitrogen-fixing efficacy by inhibiting nitrogenase (Kannaiyan et al 1997;Valiente et al 1997) and lindane degradation (Kuritz et al 1997). However, inorganic nutrient content in paddy waters and soil, especially the concentration and chemical form of fixed nitrogen appears to be crucial for this process.…”

Section: Degradation Of Chlorinated Pesticides By Wiidtype and Genetimentioning

confidence: 99%

“…On the rice paddy, activity and abundance of cyanobacterial strains positively correlated with the soluble reaction phosphate (SRP) value and negatively correlated with the dissolved inorganic nitrogen (DIN) value (Qyesada and Valiente 1996), possibly due to the inhibitory action of elevated ammonium concentrations (over 0.5 mM) on the nitrogenase activity (Valiente et al 1997). Cyanobacterial abundance increased at D1N:SRP values below 7.2.…”

Section: Degradation Of Chlorinated Pesticides By Wiidtype and Genetimentioning

confidence: 99%

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Cyanobacteria as agents for the control of pollution by pesticides and chlorinated organic compounds

Kuritz

1998

Journal of Applied Microbiology

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Cyanobacteria are phototrophic aquatic micro-organisms that are found in a variety of environments, including polluted ones. Fifteen strains of cyanobacteria that belong to three taxonomic groups are able to degrade lindane (λ-hexachlorocyclohexane, a recalcitrant pesticide). The initial degradation pathway has been studied in two filamentous nitrogen-fixing strains of Anabaena sp. PCC 7120 and Nostoc ellipsosporum. These cyanobacteria dechlorinated loindane first to pentachlorocyclohexene and then to a mixture of trichlorobenzenes, and possibly further. Lindane dechlorination by these organisms occurred only in the presence of nitrate in the medium. Both ammonium and darkness inhibited the process. This combination of observations led us to the hypothesis that the nitrate-reduction system of cyanobacteria may be involved in dechlorination. The hypothesis was proven by the analysis of Anabaena sp. transpositional mutants in four genes of the nir operon. The mutants were unable to dechlorinate lindane. However, there was no correlation between lindane dechlorination and activities of individual proteins encoded by this operon. Genetic engineering of Anabaena sp. and N. ellipsosporum that introduced linA lindane dechlorination operon from Psuedomonas paucimobilis allowed us to uncouple dechlorination from nitrate requirement. Introduction, by genetic engineering, of fcABC (the 4-chlorobenzoate dechlorination system from Arthrobacter globiformis) to Anabaena sp and N. ellipsosporum rendered these strains newly capable of 4-chlorobenzoate dechlorination both constitutively and inducible by an environmental factor.

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Soils and Rice-Fields

Whitton

The Ecology of Cyanobacteria

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Short- and long-term effects of ammonium on photodependent nitrogen fixation in wetland rice fields of Spain

Cited by 12 publications

References 11 publications

Seasonal patterns of nitrogen fixation and denitrification in oceanic mangrove habitats

Seasonal patterns of nitrogen fixation and denitrification in oceanic mangrove habitats

Cyanobacteria as agents for the control of pollution by pesticides and chlorinated organic compounds

Soils and Rice-Fields

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