@article {KNZ001315,
	title = {Saturation of NO3- uptake in prairie streams as a function of acute and chronic N exposure},
	journal = {Journal of the North American Benthological Society},
	volume = {29},
	year = {2010},
	pages = {627 -635},
	abstract = {<p>We conducted a series of stepwise NO3\&minus; additions to investigate the response of NO3\&minus; uptake to short-term (acute) changes in N concentration in 3 prairie streams. Observed NO3\&minus; uptake rates increased with short-term elevations in NO3\&minus; concentration and were consistent with linear and Michaelis\&ndash;Menten kinetics models. We compiled these data with uptake rates from additional published studies to calculate robust estimates of N uptake kinetics for prairie streams. Half-saturation coefficients based on compiled data were 6.7 \&micro;g/L for NH4+ and 67 \&micro;g/L for NO3\&minus;-N. This difference in half-saturation coefficients suggests that NH4+ is more efficiently assimilated than NO3\&minus;, indicating a preference for NH4+ as an N source. Similarly, ambient concentrations of NH4+ and NO3\&minus; were less than their respective half-saturation coefficients, and aerial uptake rates were generally \&lt;5\% of the maximum, suggesting severe limitation of N uptake at ambient conditions. The observed pattern of uptake kinetics suggests that physiological constraints limit biotic N uptake in these low-N streams and contrasts with the pattern of uptake observed in streams with chronically elevated ambient NO3\&minus; concentrations.</p>},
	keywords = {LTER-KNZ, Biogeochemistry, Kings Creek, Konza Prairie, nitrate uptake},
	doi = {10.1899/09-021.1},
	url = {https://www.journals.uchicago.edu/doi/10.1899/09-021.1},
	author = {O{\textquoteright}Brien, J.M. and W. K. Dodds}
}
