I investigate processes at the ecosystem level using statistical modelling. My main interest in research is to understand ecological processes and population dynamics of aquatic organisms at the ecosystem level, in particular those aspects that are relevant to resource management. Recently I have been investigating spatial and temporal scales needed to study the spatial distribution of fish abundance and obtain indices of abundance of fish populations in marine and freshwater ecosystems. Since fish, as other aquatic organisms, cannot be directly observed large scale population studies must rely on analysis of data from scientific surveys or commercial operations. The analysis of this information requires specialized statistical modeling. Currently my focus is in the Great Lakes.

Research Interests:

• Numerical Modeling of Coastal Hydrodynamics.
• Ice Transport and Sediment Transport Modeling.
• Model Evaluation. Coastal Nowcast/Forecast Systems.
• Coastal Meteorology.
• Physical-biological coupling.

Awards:

I am an ecologist who combines field and geospatial data and methods to study the pattern and process of ecological systems. I also strive to build bridges between science and social science.

What motivates my work is recognition of the complexity of the relationship of humans and ecological systems. These relationships and their emergent properties can be studied at different spatial scales and levels of organization. Knowledge gained from field studies, geospatial data, and analysis can be used to build models that help scientists and to understand the implications of human actions on the social and natural systems of which they are a part.

My work can be categorized in three areas: modeling and control of aggregated storage devices; power management; and system analysis of energy technologies and their impact.  I study how mechanical devices that are distributed in power systems – such as wind turbines, building thermal loads, and plug-in vehicles – influence system performance and each other.  I am drawn to problems influenced by constraints on the spatial and temporal availability of natural resources such as wind and sunlight, and where appropriate, I seek to understand the policy implications of my work. 

My research focuses on hydrologic processes, water quality modeling in the watershed, application of remote sensing to hydrology and water quality, and development of decision support systems for water resources management. I am currently collaborating with NOAA GLERL scientists to develop a distributed model for watershed hydrology and water quality assessment and its application to the Great Lakes basin.

My research focuses on how habitat variables mediate fish production, recruitment, growth and mortality.
Research interests include fisheries ecology, ecological modeling, recruitment dynamics, spatial habitat modeling, and biological/physical interactions.

Dr. Johengen is a Limnologist who oversees the research activities of the Cooperative Institute for Limnology and Ecosystems Research (CILER), which is a NOAA Joint Institute program at the University of Michigan with the NOAA-Great Lakes Environmental Research Laboratory serving as the host lab. CILER's research activities are focused around five themes including: Climate and Large-Lake Dynamics, Coastal and Nearshore Processes, Lare-Lake Ecosystem Structure and Function, Remote Sensing, and Marine Environmental Engineering. Dr. Johengen's individual research interests focus on nutrient cycling and lower food-web dynamics in the Great Lakes.

I conduct research on the Great Lakes and connecting tributaries including: work with yellow perch larvae in Lake Michigan, work with a remotely operated vehicle on offshore reefs in Lake Michigan to collect evidence of lake trout reproduction, work with exotic species, especially round and tubenose gobies and zebra/quagga mussels, and work with toxic substances, burbot, deepwater sculpin, and larval fish distribution in the Muskegon River.

My fields of specialization include assessing the influence of global climate change on contaminants in the Great Lakes; Understanding ecological thresholds in the Great Lakes; Investigating long-term trends in benthic population.

Conduct biological research pertaining to population genetics, conservation genetics, and biodiversity of aquatic species (vertebrate or invertebrate) within the Great Lakes Basin that fall in the scope of the mission of the Great Lakes Science Center and the USGS strategic plan.