Nitrification and denitrification in the rhizosphere of the aquatic macrophyte Lobelia dortmanna L.

Petersen, Nils Risgaard; Jensen, Kristoffer

doi:10.4319/lo.1997.42.3.0529

Cited by 151 publications

(21 citation statements)

References 30 publications

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“…The measured rates of total denitrification (D 14 ) varied between 0 and 34.5 lmol N/m 2 h in this study are in extremely good agreement with those of between 2 and 35 lmol N/m 2 h that have previously been reported in both non-vegetated tidal flats and seagrass meadows throughout the world (Risgaard-Petersen and Jensen 1997;Herbert 1999;Ottosen et al 1999;Risgaard-Petersen and Ottosen 2000;Welsh et al 2000Welsh et al , 2001. Unlike the previous work by Welsh et al (2000) who found no statistical difference in the rates of total denitrification throughout the year at the same sample site, statistically significant differences (Supporting Information Table S3; p < 0.05) were found in the rates of denitrification at the different sites in this study throughout the year.…”

Section: Denitrificationsupporting

confidence: 91%

“…Variable impacts of vegetation on denitrification rates compared to non-vegetated sediments have also been recorded in the literature. Risgaard-Petersen and Jensen (1997) found that the presence of the wetland macrophyte Lobelia dortmanna greatly stimulated the rate of denitrification under both light and dark conditions. In contrast Risgaard-Petersen and Ottosen (2000) found no significant difference in total denitrification rates between nonvegetated sediments and those containing Zostera marina.…”

Section: Denitrificationmentioning

confidence: 97%

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The balance between nitrogen fixation and denitrification on vegetated and non‐vegetated intertidal sediments

2016

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Rates of denitrification (isotope pairing) and nitrogen fixation (acetylene reduction) were simultaneously measured in three temperate, intertidal Zostera muelleri meadows and adjacent non‐vegetated tidal flats within Western Port, Australia. Net daily nitrogen fluxes ranged from −276 (net denitrification) to 520 μmol N/m2 d (net nitrogen fixation), and were generally positive, with only two instances of net negative fluxes. The highest fluxes were observed at the sites with the lowest water column nitrate concentrations. No significant differences in net nitrogen fluxes were found between vegetated and non‐vegetated sediments (p = 0.213). Nitrogen fixation was generally the dominant process occurring, which was stimulated in the presence of vegetation except at the most marine‐influenced site, where nitrogen fixation in non‐vegetated sediments was higher. Nitrogen fixation rates in non‐vegetated sediments were highly correlated to cyanobacterial cell counts (although no mats were present). Rates were ∼65 μmol N/m2 d at 0 cell counts, suggesting a basal rate driven within the sediment. Additional slurry experiments confirmed significant rates of nitrogen fixation within the sediment, which were stimulated by sucrose and terminated by nitrate (p < 0.05), strongly suggesting sulfate‐reducing bacteria contributed to nitrogen fixation. At the bay‐wide scale, nitrogen fixation was estimated to contribute ∼430 t N/yr compared to ∼650 t N/yr from catchment and atmospheric inputs and 230 t N/yr lost through denitrification. Sensitivity analysis confirmed that while the loss of seagrass would affect the magnitude of the bay‐wide flux of nitrogen on these tidal flats, nitrogen fixation remains the dominant process.

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Section: Denitrificationsupporting

confidence: 91%

Section: Denitrificationmentioning

confidence: 97%

The balance between nitrogen fixation and denitrification on vegetated and non‐vegetated intertidal sediments

2016

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“…DNT rates measured in ISO sediments were 8-to 100-fold higher than in bare sediments and 18-to 370-fold higher than in MIX-sediments. These increases are higher than the values measured in other lake sediments after comparing ROL vs. non vegetated sediments, i.e., within the range 0.1-11.7 increase (Bodelier et al 1996;Risgaard-Petersen and Jensen 1997;Karjalainen et al 2001). Differences appear to be higher under nutrient-limitation conditions as is the case of the ultraoligotrophic waters in the Pyrenean area.…”

Section: Discussionmentioning

confidence: 51%

“…Terrestrial and aquatic denitrification (DNT) and anammox processes are of special interest because they represent the only permanent removal pathway whereby bioavailable N is returned to inert N 2 gas (Rockstr€ om et al 2009). The presence and specific composition of rooted plants is a major factor influencing DNT rates of soils and sediments (Risgaard-Petersen and Jensen 1997). Plants can alter physicochemical factors known to control denitrification rates such as pH, oxygen, carbon sources and nitrate concentrations (Griffiths et al 1997;Gacia et al 2009).…”

mentioning

confidence: 99%

Macrophyte landscape modulates lake ecosystem-level nitrogen losses through tightly coupled plant-microbe interactions

et al. 2015

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Root functional diversity of submerged vegetation exerts a major effect on nitrogen (N) cycling in lake sediments. This fact, however, is neglected in current N-balance models because the links between the engineering role of plants and in situ microbial N cycling are poorly understood. We hypothesized that macrophyte species with high root oxygen loss (ROL) capacity promote the highest denitrification because of a higher abundance of ammonia oxidizers and tighter coupling between nitrifiers and denitrifier communities. We sampled five small ultraoligotrophic shallow lakes with abundant macrophyte cover including sediments dominated either by Isoetes spp. (high ROL), mixed communities of natopotamids (low ROL), and unvegetated sandy sediments. At each site, we quantified denitrification (DNT) rates and proxies for the abundance of denitrifiers (nirS and nirK genes), and both ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) and the diversity of nirS-harboring bacteria. Vegetated sediments showed significantly higher abundances of N-cycling genes than bare sediments. Plant communities dominated by Isoetes generated sediments with higher redox and NO 2 3 concentrations and significantly higher DNT rates than natopotamidsdominated landscapes. Accordingly, increasing DNT rates were observed along the gradient from low ROL plants-bare sediments-high ROL plants. Significantly higher abundance of the archaeal amoA gene was recorded in sediments colonized by high ROL plants unveiling a key biogeochemical role for AOA in coupling macrophyte landscape and ecosystem denitrification.The global nitrogen cycle has been strongly modified by massive industrial fixation of nitrogen gas (N 2 ) for human use and by fossil-fuel combustions (Gruber and Galloway 2008). Current concentrations of bio-available nitrogen (N) forms are higher than ever in the human era (Fowler et al. 2013). Terrestrial and aquatic denitrification (DNT) and anammox processes are of special interest because they represent the only permanent removal pathway whereby bioavailable N is returned to inert N 2 gas (Rockstr€ om et al. 2009). The presence and specific composition of rooted plants is a major factor influencing DNT rates of soils and sediments (RisgaardPetersen and Jensen 1997). Plants can alter physicochemical factors known to control denitrification rates such as pH, oxygen, carbon sources and nitrate concentrations (Griffiths et al. 1997;Gacia et al. 2009). These modifications, in turn, influence the activity, diversity and abundance of rhizosphere nitrifiers and denitrifiers populations although few studies have reported quantitative evidences of these plantmicrobial interactions in lake ecosystems (Kofoed et al. 2012). Commonly, nitrification (NT) produces NO 2 3 under oxic conditions after ammonification while DNT requires suboxic conditions and is highly dependent on both NO 2 3 transport from aerobic to anaerobic zones and changes of the in situ redox conditions (Seitzinger et al. 2006).Submersed aquatic plants (SAV)...

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“…Moreover, macrophyte beds may enhance nutrient storage through increased sedimentation of fine particulate organic matter (Kleeberg, Köhler, Sukhodolova, & Sukhodolov, 2010;Sand-Jensen, 1998). Third, aquatic plants enhance NO 3 − -N removal via the accumulation of fine sediments in macrophytes beds that promote anoxic conditions and thus sediment denitrification (Petersen & Jensen, 1997).…”

Section: Introductionmentioning

confidence: 99%

Riverine macrophytes control seasonal nutrient uptake via both physical and biological pathways

et al. 2019

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1. In low-gradient, macrophyte-rich rivers, we expect that the significant change in macrophyte biomass among seasons will strongly influence both biological activity and hydraulic conditions resulting in significant effects on nutrient dynamics.Understanding seasonal variation will improve modelling of nutrient transport in river networks, including annual estimations of export, which could optimise decision-making and management outcomes.2. We explored the relationships among seasonal differences in reach-scale nutrient uptake, macrophyte abundance, solute transport and transient storage in the River Gudenå (Denmark), a large macrophyte-rich river. We used the minimal pulse addition technique to measure uptake of ammonium, nitrate, soluble reactive phosphorus, as well as reach-scale metabolism, and surface transient storage in spring, summer, and autumn.3. We found that riverine uptake changed among seasons and was linked to macrophyte biomass via both biological activity, reflected in reach-scale metabolism, and through physical processes, as solute transport was influenced by longitudinal dispersion. In this macrophyte-rich river, seasonal changes in macrophyte biomass affected contact time between the water and biota, which influenced ammonium and soluble reactive phosphorus uptake. Using stoichiometric scaling of reachscale metabolism, we found that seasonal variation also influenced the relative contributions of autotrophic and heterotrophic biota in assimilatory uptake. 4. In summary, riverine nutrient uptake was not static, highlighting the importance of seasonality, with significant implications for modelling of nutrient export in river networks. Moreover, current management strategies that remove macrophyte biomass (i.e. weed cutting and dredging) will short-circuit the positive effects of enhanced nutrient uptake resulting from abundant macrophytes in rivers. K E Y W O R D Snitrogen, phosphorus, river, stream, transient storage | 179 RIIS et al.

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Nitrification and denitrification in the rhizosphere of the aquatic macrophyte Lobelia dortmanna L.

Cited by 151 publications

References 30 publications

The balance between nitrogen fixation and denitrification on vegetated and non‐vegetated intertidal sediments

The balance between nitrogen fixation and denitrification on vegetated and non‐vegetated intertidal sediments

Macrophyte landscape modulates lake ecosystem-level nitrogen losses through tightly coupled plant-microbe interactions

Riverine macrophytes control seasonal nutrient uptake via both physical and biological pathways

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