2022 Early Hearing Detection & Intervention Virtual Conference

March 13 - 15, 2022

<< BACK TO AGENDA

5/26/2021  |   8:30 AM - 10:30 AM   |  DISSOLVED N2:AR RATIOS DESCRIBE THE BALANCE BETWEEN DENITRIFICATION AND N FIXATION ACROSS A NITROGEN:PHOSPHORUS GRADIENT IN EXPERIMENTAL POND SYSTEMS   |  Virtual Platform

DISSOLVED N2:AR RATIOS DESCRIBE THE BALANCE BETWEEN DENITRIFICATION AND N FIXATION ACROSS A NITROGEN:PHOSPHORUS GRADIENT IN EXPERIMENTAL POND SYSTEMS

Quantifying net N2 flux, the balance between denitrification and nitrogen (N) fixation, may help solve the decades-long debate about the significance of N limitation in pond, lake, and reservoir ecosystems. We hypothesized that the stoichiometric imbalance between nitrogen and phosphorus (P) inputs into hypereutrophic experimental ponds would yield under- or over-saturated N2 gas concentrations and net zero N2 flux at the Redfield Ratio. We tested this concept by measuring diel N2:Ar patterns in twelve experimental pond mesocosms representing a N:P gradient ranging from ~2 to 110 (by atoms). Patterns in N2:Ar ratios across mesocosms varied over the diel cycle with minimum values occurring in late afternoon and maximum values occurring before or during sunrise hours. Overall, mesocosms with the lowest N:P ratios had N2:Ar values consistently below equilibrium, mesocosms with N:P ratios near Redfield ratios overlapped with equilibrium values, and mesocosms with high N:P ratios had N2:Ar values consistently above equilibrium. Our results confirm that water column N2:Ar values show promise for evaluating the direction of N fluxes within lakes and may help researchers determine the role of N fixation and denitrification in balancing stoichiometry of lakes across broad scales.

  • Nutrient cycling
  • Microbial ecology
  • Stoichiometry

Presentation:
This presentation has not yet been uploaded.

Handouts:
Handout is not Available

Transcripts:
CART transcripts are NOT YET available, but will be posted shortly after the conference


Presenters/Authors

Jason M. Taylor (), USDA, Agricultural Research Service, National Sedimentation Lab, jason.taylor@ars.usda.gov;


ASHA DISCLOSURE:

Financial -

Nonfinancial -

Thad Scott (), Baylor University, Thad_Scott@baylor.edu ;


ASHA DISCLOSURE:

Financial -

Nonfinancial -

Patrick Kelly (), Rhodes College, kellyp@rhodes.edu;


ASHA DISCLOSURE:

Financial -

Nonfinancial -

Isabelle Andersen (), Baylor University, isabelle_andesen1@baylor.edu;


ASHA DISCLOSURE:

Financial -

Nonfinancial -