Oceanography

Biogeochemistry of microbial mats

My oceanographic interests include biogeochemical analysis of hypersaline environments including isotopic analysis of methane gas emissions from these aquatic environments. I have worked in hypersaline environments from San Fransisco bay to the Baja California Peninsula.

 

As a graduate student in the Earth, Ocean and Atmospheric Sciences department at Florida State University my research focused on using stable isotopic analysis to analyze methane gas produced in microbial mats found in hypersaline environments. The analysis showed that the microbial mats found in hypersaline environments produced methane with an isotopic composition outside of values typically accepted for biologically produced methane. Higher salinity endoevaporites yielded what would be considered nonbiogenic methane based upon stable isotopic and alkane content, however incubation of crustal and algal mat samples resulted in methane production with similar isotopic values. Radiocarbon analysis indicated that the production of the methane was from recently fixed carbon.

 

This research is important because methane in the atmosphere is used as a potential marker for current or recent life on exoplanets. While the presence of methane in the atmosphere could also be a consequence of geologic activity and/or thermal alteration of ancient organic matter it could also be from microbial life similar to those found in hypersaline environments here on Earth. From our findings, we proposed an extension of the isotopic boundaries utilized for the determination of biogenic methane to avoid the possibility of misclassifying methane produced by these unique microbes.

My Skills

I believe in the fact that learning never stops and I am interested in learning new technologies that will help me be a better ocean researcher.

Ion Chromatograph
Gas Chromatograph
Isotope Ratio Mass Spectrometer
Ecological sampling techniques
Science communication

Oceanographic and Environmental Experience

Education

2013

Florida State University

Tallahassee, FL

Ph.D Biological Oceanography

Academic Advisory: Dr. Jeffrey Chanton

2006

Florida International University

Miami, FL

B.S. Marine Biology

Experience

2008-2013

Florida State University

Earth, Ocean, and Atmospheric Science

Graduate Research Assistant

I was a part of an amazing team and worked together with them to help understand the biogeochemistry of microbial mats.

2008

Florida State University

Oceanography

Teaching Assistant

I was a teaching assistant for the Marine Mammals course.

2006-2007

Florida International University

College of Arts and Sciences

Laboratory Instructor

I was responsible for teaching the laboratory courses for Human Biology, General Chemistry, and Chemistry and Society.

2006-2007

Florida International University

College of Arts and Sciences

Laboratory Research Assistant

I was a laboratory assistant as part of an amazing team working to understand the behavioral effects of predation on turtles.

Publications

2020

Aquatic Geochemistry

The effect of bacterial sulfate reduction inhibition on the production and stable isotopic composition of methane in hypersaline environments.

Kelley, C.A., Bebout, B., Chanton J.P., Beaudoin, C.S., Detweiler, A.M., Frisbee, A., Nicholson, B.E.,
Poole, J., Tazaz , A.M. & Winkler, C. (2020).
Aquatic Geochemistry, Special Edition (5-6) https://doi.org/10.1007/s10498-020-09381-z

2013

ICARUS

Redefining the isotopic boundaries of biogenic methane: Methane from endoevaporites.

Tazaz, A. M., Bebout, B.M., Chanton, J.P., Kelley, C.A., Poole, J. (2013). ICARUS, 224(2), 268-275.
https://doi.org/10.1016/j.icarus.2012.06.008

2013

Dissertation

Isotopic characterization of methane obtained from hypersaline environments

Florida State University

2012

Astrobiology

Substrate limitation for methanogenesis in hypersaline environments.

Kelley, C. A., J.A. Poole, A.M. Tazaz, J.P. Chanton, B. Bebout (2012). Astrobiology, 12(2), 89-97.
https://doi.org/10.1089/ast.2011.0703

You can access my full publication and presentation list by downloading my CV.

Photo's from the field