research

Conceptual model of nitrate removal pathways (from the 2007 Burgin & Hamilton paper in Frontiers in Ecology and Environment "Have we overemphasized the role of denitrification in aquatic ecosystems? A review of nitrate removal pathways").

 nitrogen cycling in streams AND WEtlands

We have performed several whole-stream isotopic enrichment experiments to study nitrogen cycling and food webs in Michigan streams as part of an intersite comparison involving biomes throughout North America, known as the Lotic Intersite Nitrogen Experiment (LINX). The original LINX experiments were done in 1997-98 and focused on food webs. A second generation of studies in 2002-2006 examined how human disturbances affect nitrate uptake and retention in streams. I have worked together with Dr. Jennifer Tank and her team from the University of Notre Dame on sites throughout the Kalamazoo River watershed.

More information on the LINX project can be found on our KBS LTER web site:
http://lter.kbs.msu.edu/research/areas-of-research/lotic-intersite-nitrogen-experiment-linx/
Dustin Kincaid showing off his mucky mitts in the Kellogg Forest pond.  Photo by Steve Hamilton.

michigan wetland ecology & biogeochemistry

I have an ongoing research program that examines how the hydrology of southern Michigan wetlands controls their biogeochemical and ecological characteristics, and how hydrological changes resulting from our changing climate may alter these ecosystems. A CAREER grant from NSF launched me into this research area. The area around KBS is excellent for comparative studies of wetlands because of the great diversity of these ecosystems. We have a large database of comprehensive hydrochemical variables in wetland waters that we are currently analyzing.

We became interested in alternative nitrogen uptake processes, and my former PhD student Amy Burgin spearheaded our research on these processes in wetlands and streams. Another PhD student, Lauren Kinsman, is tackling the biogeochemistry of sediment phosphorus release in lakes and wetlands, funded by NSF. Related to this work and to the LINX project is an ongoing investigation of biogeochemical processes in wetlands that experience hydrological through-flow, such as impoundments along stream courses, led by my postdoc Jon O'Brien, who is now at the University of Canterbury in New Zealand.
Zebra mussels, photo by A. Bensen (USGS, http://nas.er.usgs.gov /queries/factsheet.aspx?speciesid=5).

zebra musselS IN michigan lakes and the hudson river

For many years I worked with Dr. Orlando Sarnelle of MSU's Dept. of Fisheries and Wildlife and others to study the ecological impacts of zebra mussels (Dreissena polymorpha), an exotic species presently spreading into our inland Michigan lakes. We were particularly interested in the possible link between the mussels and the recent occurrence of noxious blue-green algal blooms in lakes that were formerly considered to be oligotrophic (i.e., low potential for algal production). This research has included several experiments in large mesocosms, as well as surveys of lakes with and without the mussels.
More recently I have been working with David Strayer and others at the Cary Institute of Ecosystem Studies to study the Hudson River's freshwater estuary, where zebra mussels are by far the dominant aquatic animal. This has been the focus of a series of NSF-funded Long-term Research in Environmental Biology (LTREB) grants.
Micaleila Desotelle processing macroinvertebrate samples from the Kalamazoo River (photo by Dave Weed).

kalamazoo river ecology

KBS lies in the watershed of the Kalamazoo River. One of my Master's students (Nicole Reid) studied the biogeochemistry of the river's reservoirs in the context of nutrient loading and eutrophication. My PhD student Leila Desotelle investigated how algal growth in the reservoirs subsidizes downstream food webs. In addition, she studied the ecological ramifications of a major oil spill into the river in summer 2010, caused by a ruptured pipeline.

Hamilton became very involved in that oil spill, offering local knowledge as well as an understanding of river and floodplain ecosystems to help inform decisions about the response.

In winter 2019-2020 a reservoir on the river that we had long studied (Morrow Lake) was drained to make repairs to the dam, and we have been sampling to look at how nutrient balances respond to the first drawdown in decades.
Lime application at the LTER.  Photo by Julie Doll.

agricultural ecology

Since 1998 I have been one of the principal investigators on the Long-Term Ecological Research project at Kellogg Biological Station, which focuses on agricultural ecology, and I served as Lead PI from 2016-18. Another major  research program at MSU and KBS is the DOE-funded Great Lakes Bioenergy Research Center. At KBS we are investigating the environmental sustainability of proposed biofuel crops, ranging from conventional corn through grass monocultures and prairie polycultures and even tree plantations. I am leading the biogeochemical and hydrological aspects of this work, working together with Dr. Phil Robertson.
In 2020 KBS became an official member of the USDA's Long-term Agroecological Research network (ltar.ars.usda.gov), after being involved since its inception.
Adelaide River, Australia.  Photo by Steve Hamilton

tropical rivers & floodplains

Much of my previous research has focused on South American rivers and floodplains, and I have had the opportunity to work on diverse topics in several river systems. During the 1990's, I worked in the Pantanal wetland of Brazil in collaboration with the Brazilian Center for Agricultural Research in the Pantanal. My research in the Pantanal has examined the biogeochemistry of wetland waters, methane production, floodplain hydrology, and remote sensing of inundation. Suzanne Sippel and I extended our work with passive microwave remote sensing to examine inundation patterns in all of the major floodplains of the continent, and in 2002 we published a synthesis paper on this work. Several Brazilian PhD students have spent several months working with me on data analysis and interpretation.

In 2002 I spent my sabbatical leave at Griffith University in Queensland, Australia, working with Dr. Stuart Bunn on dryland river ecosystems. We conducted a hydrological investigation of "waterholes" (deeper channel segments with permanent water) of the Cooper Creek system, in which we determined the relative importance of river flooding and local groundwater inputs.I have since been involved in science planning for rivers and watersheds of the tropical north. In 2008-2009 I returned for another year on sabbatical in Australia, working on tropical rivers and wetlands, with sponsorship from the Australian government in the form of a Commonwealth Environmental Research Fellowship.

For several years we  had a research project on the Napo River in Peru and Ecuador, led by my PhD student Jorge Celi. Our goal is to improve our understanding of the hydrological connectivity between the river and its vast fringing wetlands and floodplains. This is critically needed information because there are proposals for developing the Napo River into a major waterway for industrial barge transport, which would entail alterations such as dredging and perhaps straightening the channel.

I have also been working with a team  including Chris Dutton and Amanda Subalusky (both now at University of Florida), David Post (Yale), and Emma Rosi (Cary Institute), to study the effects of the hippopotamus on the water quality and biogeochemistry of rivers of the Masai Mara Reserve in Kenya.

Presently I have been thinking more about dams, both large and small. I am working with Brazilian researchers on small hydropower in the watershed of the Pantanal wetland, and on large dams on the Madeira River. I am also involved in a working group based at Cornell that is seeking to develop new approaches for basin-wide assessment and planning of large dams in Amazon region.
Caption.  Photo by Steve Hamilton.

Outreach

Our research on water resources also results in numerous opportunities for community outreach and involvement in local environmental issues. I serve as President of the Kalamazoo River Watershed Council and regularly contribute information to local governments, regulatory agencies, NGOs, and the media. Since the July 2010 oil spill in the Kalamazoo River, I have provided advice to the EPA and the pipeline company, and I have given numerous media interviews and several public talks on the spill and its ecological impacts. Examples of recent media coverage include:

Mongabay.org:
"Proposed Andean headwater dams an ecological calamity for Amazon Basin"
 [June 2015]

Inside Climate News.org: "Enbridge Faces Maximum Fine of $86 Million for Kalamazoo Spill" [August 2014]

NPR All Things Considered: "When This Oil Spills, It's 'A Whole New Monster'" [Aug. 2012]

Inside Climate News.org: "Nitrous Oxide, a Greenhouse Gas, Three Times Higher in Rivers than IPCC Estimates" [Jan. 2011]

NSF Press Release: "Global Rivers Emit Three Times IPCC Estimates of Greenhouse Gas Nitrous Oxide" [Dec. 2010]