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Nitrogen cycling in the ocean: From genes to ecosystems and from the past to the future
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Effects of antibiotics on multiple nitrogen transformation processes in aquatic environments
P-M5-06-S
Ru Wan* , Xiamen University
Shuh-ji Kao, Xiamen University
Presenter Email: wantangshi1105@163.com |
| Nitrogen is a crucial element in amino acid of all living organisms. Versatile microorganisms compete for bioavailable nitrogen (e.g., ammonium and nitrate) for growth forming a complex reaction networks connecting to carbon cycle and greenhouse gas(N2O) emission, thus, playing a role in climate change. Antibiotics are widely used as human and veterinary medicines to treat diseases, thus, promoting survival rate and growth in livestock and aquaculture operations. Unavoidably, antibiotic residues may diffuse into estuary and coastal waters leading to environmental threats and disturbing the pristine nitrogen cycle. To date, most of researches of antibiotics were focus on the development of antibiotic resistance in pathogens or nonpathogenic bacteria with limited attention on the risk of antibiotics to environmental health, not mentioning microbial-mediated nitrogen processes. We use 15>N-NH4+ and 15N-NO3- labeling technique to quantitatively examine how antibiotics may regulate nitrogen transformation pathways, such as phytoplankton assimilation, nitrification and denitrification in estuarine waters, where anthropogenically induced excess nitrogen and enriched antibiotics were observed previously. Moreover, N2O production rate and yield of nitrification and denitrification will be presented. Similar technique was also applied onto estuarine sediments to comprehensively understand the effect of antibiotics on phytoplankton bloom, nitrogen transformation and N2O production in a eutrophic estuarine ecosystem. |
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