2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/22/2019 | 9:45 AM - 10:00 AM | NITROGEN FIXATION EFFICIENCY DECREASES WITH BOTH INCREASING N:P STOICHIOMETRIC IMBALANCE AND POPULATION ACCLIMATION TO NITROGEN SUFFICIENT CONDITIONS | 253 AB
NITROGEN FIXATION EFFICIENCY DECREASES WITH BOTH INCREASING N:P STOICHIOMETRIC IMBALANCE AND POPULATION ACCLIMATION TO NITROGEN SUFFICIENT CONDITIONS
Diazotrophic cyanobacteria differentiate heterocytes to synthesize the enzyme nitrogenase under nitrogen (N) deficient conditions in order to convert atmospheric N2 into bioavailable N for vegetative cell growth. However, the efficiency by which N is acquired via fixation may be affected by the degree to which a population is acclimatized to N deficient conditions and the magnitude of stoichiometric imbalance of resources. In this study, N:P ratios in growth media were altered, and Anabaena flos-aquae which were previously gown under either N-limited or N-sufficient conditions were grown over a period of one month to simulate summer bloom conditions. Experimental blooms were sampled weekly for particulate carbon, N, phosphorus (P), dissolved nutrients, and chlorophyll-a. A. flos-aquae biomass increased proportionally to reactive N in the medium. Thus, N fixation efficiency was increased as the N deficiency relative to P decreased. Also, N fixation efficiency increased with the acclimation to N-limited conditions. This study demonstrates that cyanobacterial blooms relying on fixed N for growth yield far less biomass than blooms occurring under N sufficiency, and are less efficient at producing the cell quota of N when not previously acclimated to N deficient conditions.
- Nitrogen
- Phosphorous
- Bacteria
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Presenters/Authors
Felicia Osburn
(), Baylor University, felicia_osburn1@baylor.edu;
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Thad Scott
(), Baylor University, Thad_Scott@baylor.edu ;
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