You wrote Does anyone know of any measurements of nitrogen isotopes on NOx or acid precipitation, particularly from midwest or Great Lakes region? Thanks, Dave Hodell >> >> >>______________________________ >>David A. Hodell >>Department of Geology >>University of Florida >>1112 Turlington Hall >>Gainesville, FL 32611 >>904-392-6137 (voice) >>904-392-9294 (Fax) >>[log in to unmask] >> >> >> You may find some useful references in the book Lajtha and Michener (eds) (1994) Stable isotopes in ecology and environmental science, methods in ecology, Blackwell scientific Publications cheers stefano ------------------------------- Dr. Stefano Bernasconi Geologisches Institut ETH-Zentrum CH-8092 Zuerich Switzerland Tel. ..41-1-632 3693 fax: ..41-1-632 1080 e-mail: [log in to unmask] -------------------------------