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ChemVets

NOVEMBER CHEMVETS LECTURE


" Abiotic and Biotic Chemistry at Hydrothermal vents: pyrite nanoparticles and carbon dioxide fixation via chemosynthesis"


Dr. George W. Luther, III

Maxwell P. and Mildred H. Harrington Professor of Marine Studies


Date: November 21, 2017

Time: 12 p.m. –2 p.m.


Location: DuPont, Chestnut Run Laboratories

12:00 Lunch (Admin. Bldg.)

1:00 Lecture (Bldg. 713 auditorium)

Event Type: Open to the Public

Fee: None

Registration: Not Required


ABSTRACT:

Deep-sea hydrothermal vents and the waters in the reactive mixing zone above vent orifices appear to be an important source of fine material that can pass through normal filters (0.2 and 0.4 mm) to the greater ocean and that are useful to organisms. In this work, nanoparticles are defined operationally as that material which can pass through a 0.2 mm filter. Our group has investigated three vent sites (Lau Basin, MAR and 9 N EPR), which have black smoker chimneys that have fluids ranging from sulfide rich to metal rich. I will present chemical and physical chemical data (SEM-EDS, TEM, XRD, EELS) quantifying and showing some of the materials found in these (nano)particulate phases including pyrite, metal sulfides, silicate and aluminosilicate material. Enrichment of Mg and K in the latter suggest that reverse weathering may occur in the waters within 1-2 meters of the vent orifice where vent waters mix with cold oxygenated bottom waters.


Organisms do not reside in these hot waters (~ 360 0C), but in cooler (~60 0C) diffuse flow areas. Here CO2 fixation via chemosynthesis occurs. I will briefly describe carbon dynamics in this system and aspects of our April cruise to 9 N EPR. For those who are interested but unable to come, please check out our 11 minute highlights video on Youtube (https://youtu.be/oG7kY0K1rK4).


BIOGRAPHY:  

Dr. Luther is the Maxwell P. and Mildred H. Harrington Professor of Marine Studies in the School of Marine Science & Policy at the University of Delaware, Lewes, DE. Before his arrival at Delaware in 1986, he rose through the ranks at Kean College of New Jersey. He has been active in the American Chemical Society (e.g., councilor, North Jersey Section Chair, Division of Geochemistry chair). He has received the Geochemical Society’s Claire C. Patterson Award, The ACS Division of Geochemistry Medal and the University of Delaware’s Francis Alison Award. He is a Fellow of the ACS, AAAS, AGU and the Geochemical Society. He has authored over 250 research papers, and in 2016, wrote a textbook “Inorganic Chemistry for Geochemistry and Environmental Sciences: Fundamentals and Applications” published by John Wiley & Sons Ltd.


Dr. Luther earned a B.A. in chemistry at LaSalle College in Philadelphia and a Ph.D. in physical-inorganic chemistry at the University of Pittsburgh, which named him a Department of Chemistry Distinguished Alumnus. He has used chemistry to study environmental processes from the hydrothermal vents at the bottom of the ocean to the hot springs in Yellowstone National Park, and has developed in situ electrochemical sensors to obtain real time data. He has sought to understand microbial (archaea, bacteria and plankton) processes in the environment as well as metal speciation, which affects metal availability and the health of organisms, and how H2S can lead to death of an organism or life via chemosynthesis.