Beyond the Obvious: Emerging Contaminants and Biogeochemistry as a Cause and Solution for Nitrogen Pollution

Author

Stephanie L. DeVries, The Graduate Center, City University of New YorkFollow

Date of Degree

2-2017

Document Type

Dissertation

Degree Name

Ph.D.

Program

Earth & Environmental Sciences

Advisor

Pengfei Zhang

Committee Members

Karin Block

Zhongqi Cheng

Kevin Kroeger

Subject Categories

Environmental Microbiology and Microbial Ecology | Other Life Sciences

Keywords

nitrogen cycle, antibiotics, denitrification, nitrogen pollution

Abstract

Following a comprehensive review of the occurrence and impacts of antibiotics and related pharmaceutical compounds on the terrestrial N-cycle, three experiments were performed to explore the topic of biogeochemistry as a source or a sink for N-pollution. The first of these experiments addresses the question of whether environmentally relevant concentrations of antibiotics (µg·kg^-1) have a significant effect on denitrification or N₂O production, a question that has not been well addressed in previous studies. Having determined that there is a significant shift, the second study aims to comprehensively follow changes to soil N pools and N₂O flux alongside biogeochemical reaction rates under different soil moisture conditions. The final chapter of this research, Chapter 5, looks to biogeochemistry as a solution for some of the water quality issues associated with excess N by quantifying the rate at which sand columns inoculated with lake sediment biodegrade undesirable taste/odor compounds and toxins produced by cyanobacterial algae that proliferate in nitrogen-rich waters.

The results of this work show that the balance between soil as a source or a sink of N pollutants can be significantly disturbed by sources beyond the obvious, i.e. antibiotics. It further shows that biogeochemical activity can serve as an effective treatment for secondary N-pollution. Additional research is encouraged to test the effects of additional antibiotics and by extending the incubation period to longer time periods. In particular, there also exists a need to examine the short and long-term effects of antibiotics on soil microbial community structure. While the present work shows that endemic bacteria can degrade nuisance compounds in N-polluted waters, the efficacy of this activity may also be affected by long-term antibiotic exposure in sediment. Genetic tools including GeoChip, will help to better constrain changes that are relevant to all aspects of these findings.

Recommended Citation

DeVries, Stephanie L., "Beyond the Obvious: Emerging Contaminants and Biogeochemistry as a Cause and Solution for Nitrogen Pollution" (2017). CUNY Academic Works.
https://academicworks.cuny.edu/gc_etds/1861