Environmental Biogeochemistry Staff

A photo of Timothy Maguire wearing a black suit with a dark blue undershirt.

Dr. Timothy J Maguire, Biogeochemistry Section Leader; The Academy of Natural Sciences of Drexel University

Dr. Timothy J. Maguire is the Biogeochemistry Section Lead at the Academy of Natural Sciences in Philadelphia. With a Ph.D. from Boston University, he has conducted influential research on the effects of human populations, urban infrastructure, and agriculture on biogeochemical cycles. Tim's expertise and postdoctoral work at the University of Michigan Collaborative Institute for Great Lakes Research, NOAA Great Lakes Environmental Research Laboratory, and University of Windsor Great Lakes Institute for Environmental Research have solidified his reputation in the field. As a Philadelphia researcher, he continues to explore how human activities impact the environment and shape the future of biogeochemistry.


Dr. David Velinsky, Vice President for Academy Science; Department Head, Dept. of Biodiversity, Earth and Environmental Science, Drexel University


David is a marine biogeochemist with over 20 years experience in marine and freshwater studies related to nutrient cycling, isotope biogeochemistry, and wetland nutrient and metal geochemistry. He started as an organic geochemist studying the transport of organic compounds in estuaries and from atmospheric transport, and shifted to studies of sulfur and selenium geochemistry. He has published studies related to many aspects of biogeochemistry and has a broad range in the cycling of bioactive elements. David has a B.S. in Oceanography from Florida Institute of Technology and a Ph.D. in Chemical Oceanography from Old Dominion University.


Paul Kiry, Nutrient Lab Manager, Senior Staff Scientist IV

Paul has over 40 years of experience in all forms of environmental analysis of nutrients and trace metals. Paul, known as the chemistry guru, produces the lowest detection limits and is the point person for any chemistry related question. He has a B.S. in Biology from Delaware Valley College of Science and Agriculture and a M.S. in Environmental Science from Drexel University.


Melissa Bross, Staff Scientist II

Melissa coordinates the Section’s field activities, manages Section’s field and analytical work for DRWI, and assists Paul in the Nutrient Lab. With a background in environmental science and geology, she excels at nutrient analyses and maintaining field electronics. She has a B.S. in Environmental Science from Temple University and a M.S. in Environmental Science from Drexel University.


Tracey Curran, Staff Scientist II

Tracey coordinates the general lab facilities, manages various lab and field projects and assists with instrumentation. With degrees in molecular and cell biology and environmental science, she provides unmatched laboratory and field experience. She has a B.S. in Biology from Stockton University and a M.S. in Environmental Science from Drexel University.


Michelle Gannon, Ph.D. Candidate, Dept. of Biodiversity, Earth, and Environmental Science, Drexel University

Michelle is a Ph.D. candidate studying stable isotope and trace element chemistry in giant clam shells. She manages the rock and shell sample preparation labs, assists in the Stable Isotope Lab and runs the Environmental Chemistry Journal Group. She has a B.S. in Geological Sciences from Temple University and a M.S. in Geological Sciences from The University of Alabama.


Bill Frezel, Volunteer

Bill has been an invaluable volunteer at the Academy since 2004, specializing in the design, repair and operation of equipment and instrumentation. In his pre-volunteer life, Bill worked as an electrical engineer and has a M.S. in Electrical Engineering and a B.S. in Geobiology from Brown University.


Joseph Heiczinger, Support Staff

Joey assists in all aspects of the Section’s activities, from field sampling to lab analysis. Joey has a M.S. in Management & Leadership from Western Governors U. and a B.S. in Biology from Lock Haven University.

Dr. Bhanu Paudel, Ruth Patrick Post Doctorial Scholar


Bhanu is interested in hydrological processes, sediment-water interactions, and trace element cycling in lotic and lentic ecosystems. His current interests include understanding the impact of climate variability on aquatic resources. Bhanu has studied nutrient biogeochemistry at sediment-water interface in Texas and New Jersey estuaries. He also uses statistical modeling technique to understand the roles of environmental parameters in lotic and lentic ecosystem. Bhanu received his B.S and M.S in Environmental Science from Tribhuvan University and earned his Ph.D. in Coastal and Marine System Science from Texas A&M University-Corpus Christi.