Two similar-but-different "environmental isotope" sessions are scheduled for
the fall AGU (American Geophysical Union) meeting in San Francisco
(California, USA), December 13-17, 1999, plus several hundred other sessions
on all aspects of earth and planetary sciences.  This meeting is regularly
attended by about 8000 participants, with about 7000 abstracts.

Deadlines for submission of abstracts are very firm:   September 2 for
abstract submissions by mail, and September 9 for abstract submissions using
a web page form.  For more information, see http://www.agu.org/  .

******************************************************************

H34   Isotopic Tracers of Hydrologic and Biogeochemical Processes (Joint
with B)

This session will address recent advances in the application of stable and
radioactive tracers to the understanding of hydrologic and biogeochemical
processes in near-surface and aquatic environments. Such processes include
weathering reactions, interaction of surface and subsurface waters, organic
degradation and transport, nutrient cycling, foodweb relations, rock/water
interaction, residence time, climate change, etc. Papers describing new
analytical techniques (e.g., CF-IRMS, MC-ICPMS, etc.) or innovative methods
for applying isotopes for the solution of field-related problems are
especially welcome.

Conveners: Carol Kendall, USGS, 345 Middlefield Road, MS 434, Menlo Park, CA
94025 USA; Tel: +1-650-329-4576; Fax: +1-650-329-5590; E-mail:
[log in to unmask];
Tom Bullen, USGS, 345 Middlefield Road, MS 434, Menlo Park, CA 94025 USA;
Tel: +1-650-329-4577; Fax: +1-650-329-4538; E-mail: [log in to unmask];
Bob Dias, USGS, 345 Middlefield Road, MS 434, Menlo Park, CA 94025 USA; Tel:
+1-650-329-5603; Fax: +1-650-329-5590; E-mail: [log in to unmask]


B06   Isotopes in Biogeochemistry and Global Change (Joint with A, H, and OS)

Variations in the isotopic composition of molecules due to biotic activity
can provide substantial insight into the processes that have influenced
these compounds during their lifetimes. These isotopic signals have led to
significant advances in understanding the role of the biosphere in
biogeochemical cycling and of how these cycles have changed over time. In
this session, we encourage submission of isotope-based experimental and
modeling-based approaches to understanding natural and anthropogenic changes
to biogeochemical processes. We especially encourage submissions in fields
such as oceanography, hydrology, atmospheric science, and terrestrial
ecology that will facilitate the development of a cross-system understanding
of biogeochemical transformations in a global change context.

Conveners: Christopher Still, Carnegie Institution of Washington, Department
of Plant Biology, 260 Panama Street, Stanford, CA 94305 USA; Tel:
+1-650-325-1521; Fax: +1-650-325-3748; E-mail: [log in to unmask];
Jim Randerson, Center for Atmospheric Sciences, McCone Hall #4767,
University of California, Berkeley, Berkeley, CA 94720-4767 USA; Tel:
+1-510-642-2488; Fax: +1-510-643-9377; E-mail: [log in to unmask]