caa a22 4500 44538378X CHVBK 20180317143025.0 cr unu---uuuuu 170323e20110401xx s 000 0 eng 10.1007/s10021-011-9413-2 doi (NATIONALLICENCE)springer-10.1007/s10021-011-9413-2 Denitrification Potential in Lake Sediment Increases Across a Gradient of Catchment Agriculture [Elektronische Daten] [Denise Bruesewitz, David Hamilton, Louis Schipper] Intensification of catchment agriculture has increased nutrient loads and accelerated eutrophication in some lakes, often resulting in episodic harmful algal blooms or prolonged periods of anoxia. The influence of catchment agriculture on lake sediment denitrification capacity as a nitrogen (N) removal mechanism in lakes is largely unknown, particularly in contrast to research on denitrification in agricultural streams and rivers. We measured denitrification enzyme activity (DEA) to assess sediment denitrification potential in seven monomictic and three polymictic lakes that range in the proportion of agriculture in the catchment from 3 to 96% to determine if there is a link between agricultural land use in the lake catchment and sediment denitrification potential. We collected sediment cores for DEA measurements over 3weeks in austral spring 2008 (October-November). Lake Okaro, with 96% catchment agriculture, had approximately 15 times higher DEA than Lake Tikitapu, with 3% catchment agriculture (232.2±55.9 vs. 15.9±4.5μgNgAFDM−1h−1, respectively). Additionally, sediment denitrification potential increased with the proportion of catchment in agriculture (R 2=0.85, P<0.001). Our data suggest that lakes retain a high capacity to remove excess N via denitrification under increasing N loads from higher proportions of catchment agriculture. However, evidence from the literature suggests that despite a high capacity for denitrification and longer water residence times, lakes with high N loads will still remove a smaller proportion of their N load. Lakes have a denitrification potential that reflects the condition of the lake catchment, but more measurements of in situ denitrification rates across lake catchments is necessary to determine if this capacity translates to high N removal rates. Springer Science+Business Media, LLC, 2011 nitrogen nationallicence nitrate nationallicence DEA nationallicence land use nationallicence pasture nationallicence dairy nationallicence New Zealand nationallicence Bruesewitz Denise Centre for Biodiversity and Ecology Research, Department of Biological Sciences, The University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut Hamilton David Centre for Biodiversity and Ecology Research, Department of Biological Sciences, The University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut Schipper Louis Department of Earth and Ocean Sciences, The University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut Ecosystems Springer-Verlag 14/3(2011-04-01), 341-352 1432-9840 14:3<341 2011 14 10021 https://doi.org/10.1007/s10021-011-9413-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-011-9413-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bruesewitz Denise Centre for Biodiversity and Ecology Research, Department of Biological Sciences, The University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut NATIONALLICENCE 700 1- Hamilton David Centre for Biodiversity and Ecology Research, Department of Biological Sciences, The University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut NATIONALLICENCE 700 1- Schipper Louis Department of Earth and Ocean Sciences, The University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag 14/3(2011-04-01), 341-352 1432-9840 14:3<341 2011 14 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer