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Benthic nitrogen metabolism in a macrophyte meadow (Vallisneria spiralis L.) under increasing sedimentary organic matter loads

Soana, Elisa; Naldi, Mariachiara; Bonaglia, Stefano LU ; Racchetti, Erica; Castaldelli, Giuseppe; Bruchert, Volker; Viaroli, Pierluigi and Bartoli, Marco (2015) In Biogeochemistry 124(1-3). p.387-404
Abstract
Organic enrichment may deeply affect benthic nitrogen (N) cycling in macrophyte meadows, either promoting N loss or its recycling. This depends upon the plasticity of plants and of the associated microbial communities, as those surrounding the rhizosphere. Rates of denitrification, dissolved inorganic N fluxes and N uptake were measured in sediments vegetated by the submerged macrophyte Vallisneria spiralis L. under increasing organic matter loads. The aim was to investigate how the combined N assimilation and denitrification, which subtract N via temporary retention and permanent removal, respectively, do vary along the gradient. Results showed that V. spiralis meadows act as regulators of benthic N cycling even in organic enriched... (More)
Organic enrichment may deeply affect benthic nitrogen (N) cycling in macrophyte meadows, either promoting N loss or its recycling. This depends upon the plasticity of plants and of the associated microbial communities, as those surrounding the rhizosphere. Rates of denitrification, dissolved inorganic N fluxes and N uptake were measured in sediments vegetated by the submerged macrophyte Vallisneria spiralis L. under increasing organic matter loads. The aim was to investigate how the combined N assimilation and denitrification, which subtract N via temporary retention and permanent removal, respectively, do vary along the gradient. Results showed that V. spiralis meadows act as regulators of benthic N cycling even in organic enriched sediments, with negative feedbacks for eutrophication. A moderate organic load stimulates N uptake and denitrification coupled to nitrification in the rhizosphere. This is due to a combination of weakened competition between macrophytes and N cycling bacteria and enhanced radial oxygen loss by roots. An elevated organic enrichment affects N uptake due to hostile conditions in pore water and plant stress and impairs N mineralisation and its removal via denitrification coupled to nitrification. However, the loss of plant performance is almost completely compensated by increased denitrification of water column nitrate, resulting in a shift between the relative relevance of temporary and permanent N removal processes. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
N fluxes, Radial oxygen loss, Vallisneria spiralis, Organic enrichment, N uptake, Denitrification
in
Biogeochemistry
volume
124
issue
1-3
pages
387 - 404
publisher
Springer
external identifiers
  • wos:000355620200025
  • scopus:84930272786
ISSN
1573-515X
DOI
10.1007/s10533-015-0104-5
language
English
LU publication?
no
id
70d8283b-efb9-4d28-beae-775764e18b78 (old id 8522757)
date added to LUP
2016-01-18 17:09:31
date last changed
2017-10-01 03:09:23
@article{70d8283b-efb9-4d28-beae-775764e18b78,
  abstract     = {Organic enrichment may deeply affect benthic nitrogen (N) cycling in macrophyte meadows, either promoting N loss or its recycling. This depends upon the plasticity of plants and of the associated microbial communities, as those surrounding the rhizosphere. Rates of denitrification, dissolved inorganic N fluxes and N uptake were measured in sediments vegetated by the submerged macrophyte Vallisneria spiralis L. under increasing organic matter loads. The aim was to investigate how the combined N assimilation and denitrification, which subtract N via temporary retention and permanent removal, respectively, do vary along the gradient. Results showed that V. spiralis meadows act as regulators of benthic N cycling even in organic enriched sediments, with negative feedbacks for eutrophication. A moderate organic load stimulates N uptake and denitrification coupled to nitrification in the rhizosphere. This is due to a combination of weakened competition between macrophytes and N cycling bacteria and enhanced radial oxygen loss by roots. An elevated organic enrichment affects N uptake due to hostile conditions in pore water and plant stress and impairs N mineralisation and its removal via denitrification coupled to nitrification. However, the loss of plant performance is almost completely compensated by increased denitrification of water column nitrate, resulting in a shift between the relative relevance of temporary and permanent N removal processes.},
  author       = {Soana, Elisa and Naldi, Mariachiara and Bonaglia, Stefano and Racchetti, Erica and Castaldelli, Giuseppe and Bruchert, Volker and Viaroli, Pierluigi and Bartoli, Marco},
  issn         = {1573-515X},
  keyword      = {N fluxes,Radial oxygen loss,Vallisneria spiralis,Organic enrichment,N uptake,Denitrification},
  language     = {eng},
  number       = {1-3},
  pages        = {387--404},
  publisher    = {Springer},
  series       = {Biogeochemistry},
  title        = {Benthic nitrogen metabolism in a macrophyte meadow (Vallisneria spiralis L.) under increasing sedimentary organic matter loads},
  url          = {http://dx.doi.org/10.1007/s10533-015-0104-5},
  volume       = {124},
  year         = {2015},
}