2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/22/2018 | 2:15 PM - 2:30 PM | THE INFLUENCE OF BIOLOGICAL NITROGEN TRANSFORMATIONS ON LAKE PRODUCTIVITY: AN ANALYSIS USING LARGE-SCALE ECOLOGICAL STOICHIOMETRY | 321
THE INFLUENCE OF BIOLOGICAL NITROGEN TRANSFORMATIONS ON LAKE PRODUCTIVITY: AN ANALYSIS USING LARGE-SCALE ECOLOGICAL STOICHIOMETRY
We apply a simple stoichiometric model to characterize nitrogen (N) surpluses and deficits in lakes relative to P, and how biological N transformations relate to stoichiometry. Using the US EPA National Lakes Assessment database and other published data (n = 1970 lakes), the model showed that the proportion of lakes with a N surplus decreased with increasing chl-a concentrations. Sixty-seven percent of lakes had a N deficit relative to P when a stoichiometric boundary for N deficiency included N+P co-limitation (N:P < 23 by mass), and these lakes were losing reactive N relative to P due to net denitrification. Alternatively, 14% of lakes had a N surplus and were also losing reactive N due to net denitrification. Finally, 19% of lakes had a N surplus and were gaining N due to net N2 fixation, but these lakes represented the most unproductive lakes in the database (mean chl-a = 6 µg/L). These results indicate that, rather than ‘evolving’ P limitation, N transformations are dominated by N sinks (i.e., denitrification), which perpetuates N+P co-limitation, and even strict N limitation in some lakes.
- Biogeochemistry
- Denitrification
- Nitrogen
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Presenters/Authors
Thad Scott
(), Baylor University, Thad_Scott@baylor.edu ;
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Mark McCarthy
(), Wright State University, mjm.kingston@gmail.com;
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Hans Paerl
(), UNC Chapel Hill Institute of Marine Sciences, Hans_Paerl@unc.edu;
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