Robert O. Hall, Jr.
Associate Professor
Dept. of Zoology and Physiology
Primary production
University of Wyoming
in
Polecat
Creek
Laramie WY 82071
307-766-2877
bhall@uwyo.edu
Education:
I study streams and
rivers. I am most interested in linking population and ecosystem
processes in streams to answer the following questions: How do
organisms affect ecosystem properties? How do changes in ecosystem
function affect the composition and dynamics of populations?
I am maintaining
research on two broad fronts: biogeochemistry of nutrients and food
web studies. Food webs allow interspecific interactions, such as
predation, to be expressed in units of element flow, thus combining
attributes
of both population and ecosystem approaches. Studies of nutrient
biogeochemistry allow understanding of functions unique to streams: How
far are nutrients transported downstream, and what controls this
distance? What
is the role of stream channel processes in nutrient loss from a
watershed? Stream biota may influence nutrient cycling and transport,
e.g. snails can excrete nitrogen at rates nearly equal to demand by
autotrophs, fish
can alter nutrient cycling directly by excretion, dying (in the
case
of salmon), or indirectly via altering sedimentation. I use
whole-stream
stable isotope tracer additions provide a means to examine element flow
through the stream and compare it to flow through the biota.
Publications
with links to .pdf files
Current projects: Links provide pictures and details.
Linking whole-system carbon cycling to quantitative food webs in the
Colorado River. With Emma Rosi-Marshall, (Loyola, Chicago),
Colden Baxter (Idaho State), Ted Kennedy (GCMRC) Wyatt Cross (UW) and
Kate Behn (UW). This project examines food web flows
from
primary producers and allochthonous inputs through invertebrates and
fishes in the Grand Canyon.
Control of nitrogen transport and uptake in streams , in collaboration with Jennifer Tank, University of Notre Dame, and many others.
Interaction of streams and lakes in controlling nutrient transport
. This is a collaboration with Wayne Wurtsbaugh, Michelle Baker and Jim
Haefner at Utah State Univerity. For this project we examined how
a
stream lake-stream sequence controlled uptake, storage and transport of
N during snowmelt and baseflow seasons.
Fishes as ecosystem drivers in a Venezuelan stream. In
collaboration with Brad Taylor and Alex Flecker (Cornell)
Impact of an exotic snail, Potamopyrgus antipodarum to rivers in Yellowstone National Park . In collaboration with Mark Dybdahl, Washington State University and Billie Kerans, Montana State University.
Current graduate students / postdocs and their research
Lusha
Tronstad Ph.D. Cutthroat trout in Yellowstone Lake and
its tributaries
Lisa
Kunza Ph.D. Nitrogen fixation
in Jackson Hole streams
Erin Hotchkiss M.
S. 2007, Ph.D. Linking oxygen and carbon cycling in streams
Amber
Ulseth Ph.D. Organic matter in the Colorado, River, Grand
Canyon
Alumni/ae
Brad Taylor Ph. D. 2005. Role of sediment feeding fish on
ecosystem processes in a Venezuelan stream. Dartmouth College.
Ken Cerreto M.S. 2004 Impact of piscicide, antimycin, on stream invertebrates.
Jules Feck. M. S. 2002. Response of the American dipper to variation in water quality in streams. Wyoming DEQ, Lander, WY. Email: confluence@wyoming.com
Laura Curry M. S. 2003. Macroinvertebrate and fish assemblage
response along an urbanization gradient. Utah Division of
Wildlife Resources, Salt Lake City, UT
updated 5 Feb. 2008