Tectonic History of Ohio

For much of its geological history Ohio has remained within the tropics (approx. ±23° latitude). By the late Cambrian period (approx. 530 million years ago), Ohio was covered in a sea and would stay that way until the end of the Ordovician period (505 million years ago). Plate tectonics had shifted Ohio from being about 10° South latitude to 20° South.

During the Devonian period (410-360 million years ago) warm, shallow seas covered parts of Ohio, especially eastern Ohio. The area had shifted north and then existed around the Equator during this period. The picture included below shows the topography of Ohio and location of the shallow seas during the Devonian period (image source). The shales that cover eastern Ohio were created from the sediments that deposited in this period.

The United States during the Devonian period (approx. 410-360 million years ago)

In the late Mississippian period much of Ohio was once again covered by shallow seas. These warm, shallow seas deposited lime sediments that are seen at the surface of northwestern and east-central Ohio. As for the surface rock in Springfield (in central Ohio), much of it was created during the Devonian period. The rocks at the surface are composed of the sedimentary rocks limestone, dolomite, shale, and sandstone, which deposited from erosion.

In summary, for much of the geological record Ohio has remained in tropical climates. This tropical climate has impacted the conditions under which the sedimentary rocks in Ohio have formed. Plate tectonics have shifted Ohio northward only in relatively recent geologic history– by the Quaternary period most of Ohio was covered by glaciers.

Source

Geology of the Critical Zone, a new semester!

http://instaar.colorado.edu/temp/natl_czo_update/Research.html

A new semester begins!  There are 9 students in the Geology of the Critical Zone (Geology 170) and it is a truly transdisciplinary class.  This fall we will work to explore critical zone interactions around the themes of agricultural and urban sustainability. Springfield, Ohio is located in the Buck Creek watershed with >79% agricultural land use.  Our urban setting, also influences, land, soil, water, and life. This semester, we will partner with the city stormwater manager, Sky Schelle, to investigate the potential for vacant lots to be used as wetland sites.  Wetlands will be the thread carried through from the first Critical Zone clas, and the upper level biogeochemistry class.  Wetlands act as nutrient and sediment filters and have been used in urban water management (e.g. to address overflow from combined sewers).

How do I start out a new semester with my students?

We've already been out in the field around campus, observing outcrops and spots along Buck Creek at distinct spatial scales. We observe the critical zone and think about interactions between geo, hydro, atmo, and bio spheres.

Then to introduce the critical zone, students think about the the 3 major forcings that drive interactions between spheres (Climate, Tectonic, People). For example, to consider climate, students work to link the below figures.   How are precipitation, soil moisture,  and ecosystems related? I'll leave these for you to think about.  I've pulled others for my students to think about that relate to tectonic (e.g. mountain building) and human forcing examples.  They will be blogging more soon! 

Precipitation map of the United States, CC license

Soil Moisture Regimes of the United States, USDA, NSSC

Terrestrial Ecosystems (USGS, http://rmgsc.cr.usgs.gov/ecosystems/usa.shtml)

How We Analyze Ions

“A process of critical thinking that uses observations and experiments to investigate testable predictions about the physical universe.” By using the scientific method throughout our class experiment we have attempted to dissect the more complex issue into smaller parts to help us better understand our experiment and purpose.  We want to know does this high resolution small scale experiment help us understand trends for the large scale rivers that serve as tributaries to Buck Creek. The steps of the method we have used in our tests are choosing a guiding question to go along with our controlled experiment to seek out the big picture in our study.  Our hypothesis or guiding question is by examining Buck Creek and its surrounding wetlands does the water quality improve with increased nitrogen and more organisms as the water travels its course through the sub-tributaries of the river. To investigate our hypothesis we have put in place procedures of sampling and recording our results to put together a data set we can show and interpret at GSA. 

We have collected ion concentrations by using an automatic sampling ion chromatograph(pictured above).  An ion chromatograph analyzes the concentrations of various ions that are in the samples.  This is done by using standard solutions that we create with concentrations within the expected range for each ion.  The chromatograph then uses these standard solutions to create an equation to find the concentrations of the unknown samples.    As the sample travels through the machine each ion travels at different speeds and the machine measures this speed and produces peeks(sample peaks pictured below).  The area is then found and can correlate to what the concentrations of the ions are. 

With the small scale data we can observe how our local impact is affecting the larger tributaries such as the Ohio and Mississippi Rivers.

-Beth and Grant

Sources used:
 http://srel.uga.edu/kidsdoscience/sci-method-planes/Sci-method-definitions.pdf

Wetland Sampling Sites

The scientific method is defined as, “The principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to demonstrate the truth or falseness of the hypothesis, and a conclusion that validates or modifies the hypothesis.”

http://dictionary.reference.com/browse/scientific+method?s=t

We have already formulated our hypothesis and have submitted it to GSA.  We have read several articles that have proven our hypothesis.  We are curious to see if we will get the same results dealing with a much smaller area that we can then apply to a larger scale.  Currently we are in the process of experimenting in order to demonstrate the truth or falseness of our hypothesis about the Municipal Stadium Wetland. 

Each pin in this photo represents a place that we have

taken a water sample.

Our question about this wetland is whether or not it will act as a filter to Buck Creek by removing some nutrients that are overloaded by agricultural inputs. We chose this question by reading other scientific articles about this topic.  In the articles we read we found out that the nitrogen to silica ratio is very important to sustaining aquatic life.  We believe that this ratio will become more balanced once it has had time to filter through the wetland before flowing back into Buck Creek.  In order to test whether or not our hypothesis is true we have taken many water samples in different places throughout the wetland.  By spacing the samples out we hope to get a better idea about how the ratio of nitrogen to silica, as well as other nutrients, react as it passes through different areas of the wetland.  We took many samples at the inlet, outlet, and middle areas of the wetland to see if there was a change relative to location.  We hope that our local data will be able to contribute to the big picture.  Then we may be able to see how smaller tributaries can affect larger rivers, and ultimately the Mississippi River, which flows into the Gulf of Mexico.     

By, Lexi Crisp and TJ Mobley 

Scientific Method and Water Processing

The scientific method is the process by which scientists seek to construct an accurate representation of the world.  The first step of the scientific method is to observe and describe some sort of scientific phenomena.  The second step is to formulate a hypothesis to describe the observed phenomena.  Next, the hypothesis is used to predict the existence of other scientific phenomena.  Finally, a set of experimental tests of the predictions by several independent experimenters are designed to test the hypothesis (http://teacher.nsrl.rochester.edu/phy_labs/appendixe/appendixe.html).

The guiding question for this study is: how does the Municipal Stadium Wetland affect the water quality of the water from Buck Creek?  This question was chosen to mirror a study performed by Heidelberg University in the Great Miami River.  The hypothesis is that the wetland improves the water quality of Buck Creek by filtering out dissolved silica and dissolved inorganic nitrogen, as well as excess anions and cations from Buck Creek.  We are testing this hypothesis by collecting both spatial and temporal (diurnal) samples from the Municipal Stadium Wetland and Buck Creek.  A diurnal sample occurs over a 24 hour period, with a sample being collected hourly.  These samples were collected by an auto-sampler.  The spatial samples were collected manually, by randomly chosing 30 sampling locations within both the wetland and Buck Creek.  Sample contamination was prevented by wearing gloves and rinsing sample bottles three times prior to collection.  After collection, samples were filtered and pH was measured.  The attached photo is the filtration set up.  Filtration was used to remove sediment from the water sample.  pH was tested using a digital pH probe.  Following filtration, samples were run through an Ion Chromatograph.  This data will contribute to a larger data set of the Ohio River watershed. 

Importance of Wetlands

Nutrients are essential to life in many different ways.  For example, too much nitrate can become toxic to stream life, or too much phosphate can cause an excess growth of algae, thus depleting oxygen from streams and killing aquatic life (http://www.ornl.gov/info/ornlreview/rev26-1/net226.html).  These are just a few examples of how nutrient balance is crucial to stream ecosystem health. The study site is the Municipal Stadium Wetland, located just east of Buck Creek.  It is important as to capture pollutants and impurities from Buck Creek, so constant analysis of the Wetland's contents is crucial.

Ben

Why We Need Wetlands

Nutrients are important for every organism to grow and develop. We provide these nutrients often in the form of fertilizers which help everything grow. Fertilizers can be great and are loaded with nutrients like nitrate and phosphate that run off into rivers and streams. This over abundance of nutrients allows for overgrowth of algae and an imbalance of sustainability of the ecosystem. Too many nutrients deplete the oxygen which endanger life and create dead zones like those seen in the Gulf of Mexico. Wetlands were once drained because they were considered wasteland but we now know that wetlands like the kidneys in our bodies have a filtering function. Municipal Stadium Wetland is located parallel to Buck Creek in Springfield OH with an upstream inlet from the river that allows for overflow during flood events.

 

Melt water from Municipal Stadium Wetland making its way back into Buck Creek at the downstream outflow.

 

Buck Creek like many rivers in Ohio contains a lot of sediment and nutrients. During flood events this sediment can be filtered through the Municipal Stadium Wetland helping to clean up the quality of the water by settling out sediment and nutrients. it also acts as a storage area for water. It is winter in the wetland and there is some outflow downstream due to melting ice and input from ground water in the wetland. We will be examining the amounts of nitrogen and phosphate in the water to help us determine if the balance of nitrogen to phosphate is correct for sustaining life. We will also look at the affect Municipal Stadium wetland
is having on the Buck Creek.

 Link: www.nwrc.usgs.gov/wetlands/wetlandFeature.htm