Title Description Research Sites Related Links
Douglas Lake Water Profiles

Water temperature and dissolved oxygen profiles for various parts of Douglas Lake. These profiles span a number of investigators, time periods and locations within Douglas Lake so pay attention to the Dataset details.

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Phenology shifts in northern forest ecosystems

Large-scale phenological shifts, or timing of key life events, have been observed across many ecosystems and are consistent with changes expected with climate change. With annual temperature increases of roughly 0.2 degrees C, advancement in the timing of budburst and flowering have been widely observed. Earlier budburst and therefore longer growing seasons may have significant implications for carbon storage. Previous research has shown that increases of only one day in growing season have significantly increased forest net ecosystem productivity (NEP). However, the relationship between earlier budburst and NEP is not well established. Kellen’s research will examine the connection between phenological events at the species levels and phenological timing at the stand scale.

In contrast with the more evident relationship among increased temperature, earlier onset of budburst, and increased NEP, the connections between phenology and local, boundary-layer meteorology are much less understood. Leaf-out has been correlated with a wide variety of meteorological components including temperature, vapor pressure, and relative humidity. Kellen’s research will use precise phenological and meteorological observations to develop climate-biosphere models and determine the effects of phenological shifts on the climate-biosphere linkage so these findings can be incorporated into climate models.

Changes in timing of autumnal senescence have also been widely observed, although changes are more variable between ecosystems and more poorly understood than budburst events. Delayed leaf abscission may cause incomplete resorbtion of nutrients to storage organs as well as less N.

1. Have shifts in the timing of spring phenology occurred at Wauseon, OH in comparison to legacy data sets from the 1880's-1913? 2. How will shifts in both spring and autumn phenology impact carbon storage dynamics in northern forest ecosystems with the shift from aspen and birch dominated canopies to more heterogeneous oak and maple forests? 3. How will shifts in timing of leaf fall impact nutrient resorption dynamics? 4. What are key meteorological drivers of phenological events?

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Modelling forest growth, succession, and biogeochemistry to study the effects of disturbances on forest carbon cycling

Due to heavy logging and intense fires at the beginning of the twentieth century, the forests at UMBS are characterized by an early successional state dominated by short-lived tree species such as aspens and birches. As these species approach the end of their life span, they are expected to die off and be replaced by longer-lived, more shade-tolerant species such as white pine and red oak. These successional changes happen over a long time scale that is difficult to resolve with field observations, and may have important impacts on carbon, nutrient, and water budgets in the forests at UMBS. I am using a combination of measurements and computer modeling to characterize the effects of succession on CO2 and volatile organic compound (VOC) fluxes to the atmosphere.

I am using the LANDIS-II computer model to develop predictions of future carbon budgets at UMBS. This model simulates tree growth, establishment, mortality, and succession. The model will be parameterized using CO2 flux measurements from the FASET and Ameriflux towers, as well as aboveground biomass measurements from a number of permanent plots. The historical data from these plots will help to constrain model predictions of long-term biomass accumulation. VOC flux predictions will be constrained using measurements from a relaxed eddy accumulation (REA) system. Measurements were conducted at both the FASET and PROPHET towers in order to measure the differences in VOC emissions between forest successional stages.

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Plant responses to herbivory

Plants respond to herbivory by evolving and inducing defenses against herbivores. Though plant defenses have been studied extensively, indirect defenses have neither been incorporated into theories of plant defense, nor investigated alongside direct defenses. Volatile organic chemicals (VOCs) are gases which can be emitted by vegetation. They play an important role in biosphere-atmosphere dynamics as well as in community interactions. VOCs have been shown to contribute to indirect plant defense against herbivores by attracting predators and parasitoids (higher trophic levels) to their herbivore hosts; however, the adaptive role of these plant signals in defense has not yet been shown convincingly. Genetic and environmental variables, as well as community context, can influence plant VOC emission. For my dissertation work, I intend to implement field and greenhouse experiments in order to gauge the relative roles of genetic variation, environmental factors, atmospheric processes, community context, geographic variation, and herbivory in influencing plant VOC emission; integrate plant VOC emission into current models of plant defense theory; and determine whether VOC emission evolved as an adaptive response to herbivore damage.

Inclusion of vegetation in climate models

The inclusion of vegetation in climate models is key to understanding and simulating future climate change. Vegetation processes are often parametrized through leaf temperature yet very few measurements are available for model evaluation. The proposed work will conduct leaf temperature measurements in summer 2010 at the UM Biological Station, and results will be used to develop a new, experimental research avenue for the PI. Funds will support one graduate student and provide field equipment and travel to UMBS.

UMBS AmeriFlux Tower
RANN: Research Applied to National Needs

In the early 1970s the University of Michigan Biological Station initiated a series of research projects concerning the quality of the lakes in Northern Michigan under the support of the National Science Foundation through the Research Applied to National Needs (RANN) program. Dr. John Gannon joined the Biological Station's staff in 1972 and directed this program for six years. This research had significant impacts on water quality management of lakes throughout Northern Michigan. The Biological Station continued to receive grants for water quality research for several years after the RANN program had terminated.

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Ozone reactivity rates with respect to biogenic volatile organic compounds (VOC)

A three week experiment associated with the CABINEX project based around the PROPHET tower. Project goal is to examine ozone reactivity rates with respect to biogenic volatile organic compounds (VOC). Comparison of these measured reactivity rates with lab studies may suggest that there are unaccounted reactions taking place that are currently not understood.

Using branch enclosure techniques to isolate biogenic VOC emissions, ozone will be introduced to reactivity chambers and allowed to react. Using differential ozone monitors, ozone reactivity rates with respect to VOC reactions may be determined. Additionally, VOC samples will be taken before and after the addition of ozone. Samples will be analyzed using GC/MS/FID.

UMBS PROPHET Tower
Soil organic matter response to simulated nitrogen deposition

I am examining how soil organic matter biochemistry responds to chronic simulated N deposition at the nearby N gradient experiment. Specifically, I am looking at the process of lignin degradation in 4 sugar maple forests as part of the long term N gradient experiment.

Michigan Gradient Study Plot
The U of M Flying Fish

The Marine Hydrodynamics Laboratory (MHL) at the University of Michigan is currently working on a project for the Defense Advanced Research Projects Agency (DARPA) to develop an autonomous buoy for persistent surveillance in the open ocean. The vehicle, which we call the "U of M Flying Fish," is a collaborative effort with faculty from the MHL, Aerospace Engineering and EECS Departments, and has given us the opportunity to pull together a great team.  The idea of this autonomous vehicle is that it quietly drifts to the edge of its watch circle, harnessing and harvesting energy from sun, wind, and waves as it drifts. Once it reaches the edge, it takes off like a seabird and flies to the other side of the circle where it autonomously lands and begins the drift cycle again. For a small vehicle like this, most waves look like those in the "the perfect storm." By flying over them we minimize energy used in transit, maintain a long-term energy balance (i.e. no refueling required), and give more time for sensor operations without noise from the vehicle. We envision fleets of these vehicles deployed for a variety of environmental monitoring applications.  Our work at the University of Michigan Biological Station is a demonstration of the energy havesting and autonomous ability of the Flying Fish. Douglas Lake will be used to demonstrate this vehicle's autonomous flight and ability to remain within a watch circle. 

Douglas Lake
Effect of zebra mussels (Dreissena polymorpha) and land use changes on trophic state of lakes in northern Michigan

Limnology 2010 Class PhotoInvasive species cause massive damage to the environment, threaten human health, and depress the economy. Zebra mussels (Dreissena polymorpha) first invaded North America in 1988 and have had dramatic effects on lake ecosystems they have colonized. They are prolific filter feeders, effectively decreasing phytoplankton densities and increasing water clarity, thereby altering the physical and biological structure of lakes. Our class will quantify changes in water column nutrient, biological, and physical conditions among 6 lakes (Black, Mullett, Burt, Douglas, Munro, and Long) in an effort to compare current lake conditions to those in the 1970s (RANN). We will also analyze water chemistry and algal data collected by volunteers before and after the introduction of the zebra mussel (Tip of the Mitt Watershed Data). In addition, students will conduct a series of smaller research projects investigating other ways zebra mussels are affecting inland lakes. These efforts will help to assess how conditions in the lakes have changed since the 1970s. Furthermore, we hope to use these data to assess whether zebra mussels or other factors caused these alterations.