caa a22 4500 445893788 CHVBK 20180317145625.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s10750-010-0358-9 doi (NATIONALLICENCE)springer-10.1007/s10750-010-0358-9 Hypolimnetic phosphorus and nitrogen dynamics in a small, eutrophic lake with a seasonally anoxic hypolimnion [Elektronische Daten] [Deniz Özkundakci, David Hamilton, Max Gibbs] In situ estimates of sediment nutrient flux are necessary to understand seasonal variations in internal loading in lakes. We investigated the sources and sinks of nutrients in the hypolimnion of a small (0.33km2), relatively shallow (18m max. depth), eutrophic lake (Lake Okaro, New Zealand) in order to determine changes in sediment nutrient fluxes resulting from a whole lake sediment capping trial using a modified zeolite phosphorus inactivation agent (Z2G1). Sediment nutrient fluxes in the hypolimnion were estimated as the residual term in a nutrient budget model that accounted for mineralisation of organic nutrients, nutrient uptake by phytoplankton and mixing, nitrification, adsorption/desorption and diffusion of dissolved nutrients at the thermocline. Of the total hypolimnetic phosphate and ammonium fluxes during one period of seasonal stratification (2007-08), up to 60 and 50%, respectively, were derived from the bottom sediments, 18 and 24% were due to mineralisation of organic species, 36 and 28% were due to phytoplankton uptake and 9 and 6% were from diffusion across the thermocline. Adsorption/desorption of phosphate to suspended solids and nitrification were of minor (<8%) importance to the total fluxes. Any reduction in sediment nutrient release by Z2G1 was small compared with both the total sediment nutrient flux and the sum of other hypolimnetic fluxes. Uneven sediment coverage of Z2G1 may have been responsible for the limited effect of the sediment capping layer formed by Z2G1. Springer Science+Business Media B.V., 2010 Eutrophication nationallicence Lake Okaro nationallicence Internal loading nationallicence Lake restoration nationallicence Sediment capping nationallicence Mineralisation nationallicence Özkundakci Deniz Centre for Biodiversity and Ecology Research, University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut Hamilton David Centre for Biodiversity and Ecology Research, University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut Gibbs Max NIWA, National Institute of Water and Atmospheric Research Ltd, PO Box 11-115, 3251, Hamilton, New Zealand aut Hydrobiologia Springer Netherlands 661/1(2011-02-01), 5-20 0018-8158 661:1<5 2011 661 10750 https://doi.org/10.1007/s10750-010-0358-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-010-0358-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Özkundakci Deniz Centre for Biodiversity and Ecology Research, University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut NATIONALLICENCE 700 1- Hamilton David Centre for Biodiversity and Ecology Research, University of Waikato, Private Bag 3105, 3240, Hamilton, New Zealand aut NATIONALLICENCE 700 1- Gibbs Max NIWA, National Institute of Water and Atmospheric Research Ltd, PO Box 11-115, 3251, Hamilton, New Zealand aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 661/1(2011-02-01), 5-20 0018-8158 661:1<5 2011 661 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer