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Regulation and role of epiphytic nitrification and denitrification in macrophyte-dominated systems

Eriksson, Peder LU (2000)
Abstract
This thesis examines mechanisms regulating bacterial nitrification and denitrification in attached microbial communities on surfaces of aquatic macrophytes. It also evaluates the role of epiphytic nitrification and denitrification for the nitrogen turnover in macrophyte-dominated nutrient-rich freshwaters.



Epiphytic nitrification is promoted in light and epiphytic denitrification occurs mainly in dark, because the metabolic activity of the aquatic macrophyte and its epiphytes induce in light high and in dark low oxygen concentrations in epiphytic communities. Epiphytic nitrification and denitrification are also affected by the physical and chemical characteristics of the aquatic macrophyte. The spatial distribution of... (More)
This thesis examines mechanisms regulating bacterial nitrification and denitrification in attached microbial communities on surfaces of aquatic macrophytes. It also evaluates the role of epiphytic nitrification and denitrification for the nitrogen turnover in macrophyte-dominated nutrient-rich freshwaters.



Epiphytic nitrification is promoted in light and epiphytic denitrification occurs mainly in dark, because the metabolic activity of the aquatic macrophyte and its epiphytes induce in light high and in dark low oxygen concentrations in epiphytic communities. Epiphytic nitrification and denitrification are also affected by the physical and chemical characteristics of the aquatic macrophyte. The spatial distribution of nitrification in emergent macrophyte wetlands is related to the species composition of the emergent vegetation, possibly because of a macrophyte species-related release of organic nitrification inhibitors. Contrasting to nitrifying bacteria, which are lithotrophic, denitrifying bacteria use organic substances as an energy source and are therefore stimulated by the release of organic matter from aquatic macrophytes.



Epiphytic communities support more denitrification in nutrient-rich than in nutrient-poor environments. In lakes and ponds, epiphytic denitrification is higher at sheltered locations than at locations exposed to wind-induced water movements or currents. In flowing water, epiphytic denitrification occurs mainly at low oxygen concentrations in the surrounding water. However, because aquatic macrophytes impede water flow and induce low oxygen concentrations in dark, epiphytic denitrification can be present within dense vegetation despite of high oxygen concentrations in the surrounding water. Epiphytic nitrification is almost unaffected by flow conditions, and can occur both in light and in dark.



In shallow-water systems such as treatment wetlands, aquatic macrophytes often provide most of the accessible surface area for attached nitrifying and denitrifying bacteria affecting the nitrogen turnover. Aquatic macrophytes differ in their capacity to support epiphytic nitrification and denitrification. Therefore, a proper selection and management of the right plants might significantly improve the nitrogen removal efficiency of aquatic treatment systems. Conclusively, nitrification and denitrification can have a large impact on the amount and species of dissolved inorganic nitrogen in macrophyte-dominated systems, and thereby influence the functioning of these ecosystems. (Less)
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author
opponent
  • Professor Revsbech, Niels Peter, Biologisk Institut. Mikrobiel Økologi, Aarhus Universitet, Danmark
organization
publishing date
type
Thesis
publication status
published
subject
keywords
marine biology, Hydrobiology, submerged, emergent, epiphyton, bacteria, nitrate, wetland, nitrogen, littoral, aquatic ecology, limnology, Marinbiologi, limnologi, akvatisk ekologi
pages
90 pages
publisher
Department of Ecology, Lund University
defense location
Blue Hall, Ecology Building, Sölvegatan 37, Lund, Sweden
defense date
2000-02-11 10:00
external identifiers
  • Other:ISRN: SE-LUNBDS/NBLI-00/1039+90pp
ISBN
91-7105-126-0
language
English
LU publication?
yes
id
228257a3-057a-4709-b640-d376be232a38 (old id 40230)
date added to LUP
2007-06-20 14:46:01
date last changed
2016-09-19 08:45:08
@misc{228257a3-057a-4709-b640-d376be232a38,
  abstract     = {This thesis examines mechanisms regulating bacterial nitrification and denitrification in attached microbial communities on surfaces of aquatic macrophytes. It also evaluates the role of epiphytic nitrification and denitrification for the nitrogen turnover in macrophyte-dominated nutrient-rich freshwaters.<br/><br>
<br/><br>
Epiphytic nitrification is promoted in light and epiphytic denitrification occurs mainly in dark, because the metabolic activity of the aquatic macrophyte and its epiphytes induce in light high and in dark low oxygen concentrations in epiphytic communities. Epiphytic nitrification and denitrification are also affected by the physical and chemical characteristics of the aquatic macrophyte. The spatial distribution of nitrification in emergent macrophyte wetlands is related to the species composition of the emergent vegetation, possibly because of a macrophyte species-related release of organic nitrification inhibitors. Contrasting to nitrifying bacteria, which are lithotrophic, denitrifying bacteria use organic substances as an energy source and are therefore stimulated by the release of organic matter from aquatic macrophytes.<br/><br>
<br/><br>
Epiphytic communities support more denitrification in nutrient-rich than in nutrient-poor environments. In lakes and ponds, epiphytic denitrification is higher at sheltered locations than at locations exposed to wind-induced water movements or currents. In flowing water, epiphytic denitrification occurs mainly at low oxygen concentrations in the surrounding water. However, because aquatic macrophytes impede water flow and induce low oxygen concentrations in dark, epiphytic denitrification can be present within dense vegetation despite of high oxygen concentrations in the surrounding water. Epiphytic nitrification is almost unaffected by flow conditions, and can occur both in light and in dark.<br/><br>
<br/><br>
In shallow-water systems such as treatment wetlands, aquatic macrophytes often provide most of the accessible surface area for attached nitrifying and denitrifying bacteria affecting the nitrogen turnover. Aquatic macrophytes differ in their capacity to support epiphytic nitrification and denitrification. Therefore, a proper selection and management of the right plants might significantly improve the nitrogen removal efficiency of aquatic treatment systems. Conclusively, nitrification and denitrification can have a large impact on the amount and species of dissolved inorganic nitrogen in macrophyte-dominated systems, and thereby influence the functioning of these ecosystems.},
  author       = {Eriksson, Peder},
  isbn         = {91-7105-126-0},
  keyword      = {marine biology,Hydrobiology,submerged,emergent,epiphyton,bacteria,nitrate,wetland,nitrogen,littoral,aquatic ecology,limnology,Marinbiologi,limnologi,akvatisk ekologi},
  language     = {eng},
  pages        = {90},
  publisher    = {ARRAY(0x941d820)},
  title        = {Regulation and role of epiphytic nitrification and denitrification in macrophyte-dominated systems},
  year         = {2000},
}