The conceptual models were compiled by researchers in collaboration with a wide range of stakeholders from Natural Resource Management groups, universities and government agencies and based on available scientific information.
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Outputs of nitrogen (N) from lacustrine wetlands (lakes) are due to surface water flows, groundwater flows, floodwater, gas, sediment, and animals.
Denitrification could be high in some locations within lakes, especially at the edge, where macrophyte cover is high. Sediment may also alternate between aerobic and anaerobic conditions, which can affect the denitrification process, particlularly at the bottom of lakes.
Export of nitrogen as N2O is likely to occur as a result of incomplete denitrification and nitrification. Less than 1% of denitrified N is converted to N2O.
Surface and groundwater
During the dry season, outputs of nitrogen from lakes are more likely through groundwater flows. In the wet season, large and sporadic pulses of floodwater will transport dissolved and particulate nutrients out of the wetland. Outputs from groundwater and floodwater are likely to be lower than inputs in most lakes due to processes inside wetlands, i.e. denitrification, sedimentation and vegetation uptake. However, in some lakes with low water/soil ratios, and low macrophyte cover, the outputs could be similar to the inputs.
Macrophytes can be flushed out of lakes during flooding or strong rainfall events.
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^ Houston, WA & Duivenvoorden, LJ (2002), 'Replacement of littoral native vegetation with the ponded pasture grass Hymenachne amplexicaulis: effect on plant, macroinvertebrate and fish biodiversity of backwater in the Fitzroy River, Central Queensland, Australia', Marine and Freshwater Research, vol. 53, pp. 1235-1244.
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^ Seitzinger, S, Harrison, JA, Bohlke, JK, Bouwman, AF, Lowrance, R, Peterson, B, Tobias, C & Vand, D (2006), 'Denitrification across landscapes and waterscapes: A synthesis', Ecological Applications, vol. 16, no. 6, pp. 2064-2090.
Last updated: 31 July 2021
This page should be cited as:
Department of Environment and Science, Queensland (2021) – Outputs, WetlandInfo website, accessed 1 February 2023. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/ecology/processes-systems/nitrogen-concept-model/lacustrine/outputs.html