AQUATIC ECOLOGY
The conservation of aquatic ecosystems will become increasingly critical in the new century, and streams provide a model ecosystem for illustrating the operation of basic ecological processes and pressures imposed by human exploitation. Their relatively easy access and abundance in many landscapes make streams ideal places for instruction and research in ecology.
RESEARCH
My research has focused on the effects of 1) restoration strategies and 2) seasonal change on ecosystem processes in aquatic environments. Both of these factors have the potential to alter rates of nutrient cycling, metabolism, microbial communities and organic matter dynamics via changes in light, litter inputs, temperature, and stream substratum types. However, few studies have considered the interaction between seasonal dynamics and restoration projects in their evaluations.
STUDY SITES: RURAL & URBAN
To date, my work has centered on the influence of stream restoration on ecosystem function in northern Michigan. In current and future research projects, I am applying my experience studying stream restoration in a rural context towards understanding restoration initiatives of aquatic ecosystems in the New York City metro area. The ecosystem pressures in rural and urban environments
are different (i.e., legacy of logging vs. human population pressure and
industrial pollution), but the tools and paradigms used in the analyses are identical.
Urban streams have modified hydrology and a greater probability of having chemical and particulate pollution than rural streams.
(Photos courtesy of Dr. Laura Johnson for LINX II)
ONGOING PROJECTS
The relationship between land use patterns and spatial variability
in nutrient concentration and limitation in an urban river (
The influence of oyster restoration on sediment N cycling: an ecosystem approach (Click for more information)
PAST PROJECTS
Rural stream restoration: While the Upper Peninsula of Michigan was major center of logging industry in the late 19th and early 20th centuries, recreational activities such as hunting and fishing are now stronger economic drivers in the region. River restoration is an important goal of management agencies in order to increase production of native brook trout and attract visitors.
State, Shane, and Walton Creeks are forested headwater streams near Kenton, Michigan
TEACHINGGeneral Biology 1003: Baruch College
Pictures of Gen Biology students voluteering:
http://tim.hoellein.googlepages.com/bio1003volunteerpictures
Undergraduate Teaching Assistant: Principles of Biology, Diversity and Function, Experimental Biology
Graduate Teaching Assistant: Aquatic Ecology
Teaching Apprentice: General Ecology
Guest Lecturer: Aquatic Ecology, General Ecology, Human Impacts and the Environment, Stream Ecology, and Stream Ecology: Methods, Loyola University of Chicago and University of Notre Dame
Certification of Teaching Excellence in Biological Sciences. University of Notre Dame 10/15/06
Kominoski, J.S.,
T.J. Hoellein, C.J. Leroy, C.M.
Pringle, and C.M. Swan. In press. Beyond species richness: expanding
biodiversity-ecosystem functioning theory in detritus-based streams. River Research and Applications.
Kominoski, J.S., T.J. Hoellein, J.J. Kelly, and C. M. Pringle. 2009. Does mixing litter of different qualities alter stream microbial diversity and functioning on individual litter species? Oikos 188:457-463.
Entrekin, S.A., J.L. Tank, E.J. Rosi-Marshall, T.J. Hoellein,
and G.A. Lamberti. 2008. Responses in organic matter accumulation and
processing to an experimental wood addition in three headwater streams.
Freshwater Biology 53:1642–1657.
Hoellein, T.J., J.L. Tank, E.J. Rosi-Marshall, S.A. Entrekin, and G.A. Lamberti. 2007. Controls on spatial and temporal variation of nutrient uptake in three Michigan headwater streams. Limnology and Oceanography 52 (5) 1964-1977. Hoellein et al. 2007.pdf
Entrekin, S.A., E.J. Rosi-Marshall, J.L. Tank, T.J. Hoellein, and G.A. Lamberti. 2007. Macroinvertebrate secondary production in forested sand-bottom streams of the Upper Midwest. Journal of the North American Benthological Society. 26 (3): 472-490. Entrekin et al. 2007.pdf
LONG-TERM GOALS
As a new professor at Baruch College, my career vision is to combine environmental research with teaching and public service. My overarching goal is to influence public awareness and restoration of local aquatic ecosystems through research, education, and outreach. I am also keenly interested in collaborating with other instructors, researchers, and generally interested citizens to include ecological perspectives in subjects such as ethics, law, economics, and social justice. It's my view that interdisciplinary collaboration will ensure resources are directed towards the implementation of projects that promote ongoing benefits for ecosystem and public health.
PROFESSIONAL ORGANIZATIONS
North American Benthological Society
