GLOBAL CLIMATE/ENVIRONMENTAL CHANGE

BACKGROUND: The deep sea floor contains a record of earth conditions slowly, and often continuously, accumulated in the microfossil skeletons of marine plankton and benthos. Marine sediments are a nearly complete record book of change through time in the great physical, chemical and biological systems of the oceans. Since the oceans are the lower boundary layer of the atmosphere, the source of water and heat to the atmosphere and the climate system component with the greatest mass and inertia, the marine record provides us with a view of a key element of planet Earth's living and ever changing environmental story. An exciting example of ocean-atmosphere dynamics is the El Nino phenomenon.

WORK BEING DONE AT NIU
My work, and that of my students', has focused on reconstructing patterns of surfaceocean biological productivity. These patterns are directly linked to surface ocean currents, atmospheric circulation and the distribution of important chemicals (like carbon dioxide). For example, oceanic biology modifies the exchange of carbon dioxide between the ocean and the atmosphere, and the oceans ultimately strongly influence atmospheric carbon dioxide content. This may be important to the temperature regulation of the planet since carbon dioxide is a Greenhouse Gas.

Reconstructing past ocean properties, like ocean productivity, requires Tracers. These are features of the ocean sediments that we can interpret in terms of ocean characteristics we are interested in. Our work shows that the abundances of species of benthic, bottom dwelling, micro-organisms called Foraminifera are directly related to the biological productivity of the overlying oceanic surface waters

Students and I have combined stable isotope, geochemical (see the department's excellent and developing analytical capabilities) and micropaleontological techniques to reconstruct oceanic chemical and biological changes linked to major changes in atmospheric greenhouse gases over the recent Geological Past. We continue to hunt for mechanisms that drive global climate change and that will influence future global warming.

A Little More Detail:
The Open Tropical Ocean
Background: The cycling of a number of elements is tied to biological productivity in the oceans. For example, phosphorus and nitrogen are essential to biological productivity in the oceans and in turn have their distributions within the water column strongly affected by plant and animal activity. Additionally, carbon dioxide is absorbed from the atmosphere and into the oceans by physical processes, but also by the surface ocean biological "pump" which draws carbon out of the water/atmosphere and into organic matter which settles into the deep sea. Understanding the changes that might occur in global element cycles with climate change includes understanding the behavior of the marine biotic system and changes in plant productivity.

Also, the exchange of CO2 between the oceans and atmosphere is influenced by the ratio of organic carbon (take up CO2) to calcite (release CO2) production in the surface ocean and the consequent organic carbon to calcite flux ratio of particles settling into the deep sea. The particle ratio depends on the composition of plankton communities living in the surface ocean, and these respond primarily to chemical stimuli (essential nutrients and trace elements) which control the degree to which communities are composed of carbonate or non-carbonate (opal) producers.


WHAT WE ARE DOING: Understanding how global biogeochemical cycles might change requires that we examine the behavior of these cycles as they respond to a variety of conditions different from those we see on earth today. We have developed means for reconstructing oceanic biological activity (open ocean biological productivity) over time using benthic (bottom dwelling organism) microfossils recovered from deep ocean sediments. Our techniques have application to the global ocean and allows us to examine the behavior of the marine biosystem over longer stretches of time and under environmental conditions different from the present. Currently, we are concentrating on reconstructing marine biological productivity in the tropical oceans during the last 150,000 years. This is a time period encompassing large global environmental changes.

Additionally, we have developed new techniques for reconstructing past fluxes of biogenic components to the deep sea so that we can evaluate changing organic carbon and calcite flux ratios. This work involves integration of the microfossil record with chemical, isotopic and radiochemical analyses of deep sea sediments.
In pursuing these research goals we have developed a new inorganic isotope research laboratory which includes a Thermofinnigan MAT253 stable isotope ratio mass spectrometer and an ELEMENT II ICP-MS.

El Nino and the Coastal Tropical Pacific

Background: Off the coast of Peru in South America one of the largest climate phenomena of the planet expresses itself. This is the El Nino-ENSO oscillation. Periodic warming and cooling of the ocean surface cause climate changes felt all over the globe.The reasons for these temperature cycles are still obscure. Interestingly, during the early to middle Holocene (8000 to 5000 years ago) they didn't exist. What has caused ENSO to develop over the past 4000 years?

To link the ocean to the continents and the human experience we have started research in collaboration with colleagues in the Department of Anthropology at Northern Illinois University. Coastal Peru hosts a number of amazing archeological sites which are the remains of city states which flourished 8,000 to 4,000 years ago. These people collected and ate shellfish and tossed the debris into their garbage dumps. These shells record, in their geochemistry, the condition of the ocean off Peru during the early to middle Holocene. We are using the archeological sites, and their shells, to discover why El Nino operated differently at that time, and how this affected climate.

MID-WESTERN GEOLOGY AND STRATIGRAPHY
BACKGROUND: : The upper midwest is a classic area for cratonic Paleozoic Stratigraphy and Paleoenvironments. The best represented time intervals are the Ordovician and the Pennsylvanian. The former has fascinating outcrops featuring many aspects of carbonates and the interplay of carbonate and clastic sedimentation in relation to sources and paleotopography. The Pennsylvanian presents interesting problems in correlation and shifting facies in relation to fluctuating sea-level in cyclothems.

WHAT ARE WE DOING?

I have supervised student work on Ordovician paleoenvironments including a Masters thesis on The Distribution and Paleoecology of Conodonts in northern Illinois, Southern Wisconsin and Southern Minnesota. I have a personal interest in the LaSalle Cyclothem and associated facies shifts and distributions in the Ottawa region of northcentral Illinois. A number of interesting problems concerning facies distributions and vertical succession below and within the LaSalle Limestone remain to be solved.

WATER RESOURCES
BACKGROUND: Intensive land use in the upper mid-west has a strong impact on surface waters and chemical cycles in the area. Large scale farming has exposed soils to erosion and greatly increased the sediment load of streams and rivers. Agrichemical application has strongly influenced the chemistry and ecology of water bodies, some rivers in the region exceed the allowable nitrate concentration for example. In some areas agrichemicals have seeped into the ground water system affecting the quality of well water. In more urban areas the over rapid run-off from large areas of concrete leads to flooding in rivers and streams, and household and industrial chemicals influence water quality and chemistry. Often, the fate of the added chemicals and the sources and cycles these chemicals are involved in are not well defined.

WHAT ARE WE DOING?
I have an interest in the biogeochemical cycles of surface waters, particularly those of biologically important elements like nitrogen and phosphorus. In pursuing this interest I have worked with students on projects involving soil chemistry, biogeochemical cycles in individual watersheds and the geochemistry of groundwaters in developing suburban areas. Some titles of student projects are listed below:

SENIOR THESES:

A box model of the nitrogen cycle in the Vermilion River Watershed, northcentral Illinois

Seasonal and Regional Variability in Nitrogen transport of the Vermilion River, northcentral Illinois

Phosphorus transport of the Vermilion River, northcentral Illinois

The relation between River discharge and Nitrogen transport, Vermilion River, Illinois

MASTERS THESES:

Organic carbon content and distribution in Agricultural land under different treatments, northern Illinois

Nitrogen species and distributions in Groundwaters beneath a region of mixed agricultural and suburban land use