2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/21/2018 | 11:00 AM - 11:15 AM | IN SITU CHAMBER EXPERIMENTS REVEAL DRIVERS OF DISSOLVED NITROGEN AND PHOSPHORUS ATTENUATION DURING SUMMER IN THE TUKITUKI RIVER, NEW ZEALAND | 330 B
IN SITU CHAMBER EXPERIMENTS REVEAL DRIVERS OF DISSOLVED NITROGEN AND PHOSPHORUS ATTENUATION DURING SUMMER IN THE TUKITUKI RIVER, NEW ZEALAND
Instream attenuation alters downstream nutrient concentration and form but limited understanding of attenuation drivers limits source-to-sea water quality modelling. We investigated drivers in the Tukituki using in situ chambers, complimenting reach-scale measurements.
Light influenced N dynamics more strongly than P dynamics. N areal uptake (U) and uptake velocity (Vf ) were significantly higher in light than dark for TDN and its components (NH4-N, NO3-N, DIN), except for DON. In contrast, uptake of TDP and DRP did not differ between light and dark. Release of DON and DOP made uptake of TDN and TDP lower than DIN and DRP, respectively.
Drivers most strongly correlated with U DIN in the light were Nett Production > Gross Production > DRP > Chl. a > PAR. A regression model for U DIN (r2 = 60%) included initial DRP and Chl. a. DRP uptake was lower for cyanobacterial periphyton than filamentous greens and diatoms and had stronger relationships with environmental drivers than DIN uptake in the light when cyanobacteria data were excluded. Cyanobacteria had lower mass ratios of C/N and C/P than filamentous greens and diatoms, indicating greater internal nutrient reserves or different stoichiometric requirements.
- Biogeochemistry
- Periphyton
- Water Quality
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Presenters/Authors
John Quinn
(), National Institute of Water and Atmospheric Research (NIWA), John.Quinn@niwa.co.nz;
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Sherry Schiff
(), University of Waterloo, sschiff@waterloo.ca;
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