As the weather cools – the Wooster Geology Climate Change class ventured out in the field one more time. For the remainder of the semester we will try to get some work done. Two sites were visited – the Cedar Creek Mastodon Site and the OARDC.
Two weeks ago a pit was dug from our coring sites to the Mastodon excavation site. The mission was to link the cores to the archaeological site.
The general stratigraphy of the mastodon site. The muds have a high calcium carbonate content that helped preserve the bones and tusk. Note the plow horizon about 25 cm down – the trip also focused on the agricultural history of Ohio and the role it plays in climate change.
Jeff Dilyard, who hosted us at the site, explains to the class that a GPR (ground penetrating radar) survey identified an anomaly at this location. Isabel probed the area (see below) and “clunked” on a tile.
Isabel above used a tile probe to investigate the subsurface (note the chin method she is employing).
What is a “tile”? above is an old drainage tile from the site. This one is plugged with mud and the plugging was the reason the mastodon was discovered. New tiles were installed last year and the digging brought up the original tooth of the mastodon. Tile and draining of the Midwest allowed for our great agricultural history. In addition, the tile and draining allowed widespread plowing that released the carbon in naturally sequestered organic rich wetland soils to the atmosphere.
The crucial end of the backhoe pit where probing and sampling links the bog cores to the mastodon site.
A quick stop ate the Triplett-Van Doren Experimental Plot. For over 50 years a variety of experiments have been underway here. We discussed the side-by-side no-till and mold board plowed sites and their ability to sequester carbon. Not plowing (no-till) sequesters carbon and mitigates erosion. Less carbon dioxide to the atmosphere and less sediment flux on the landscape.
A darker colored soil in the core barrel above shows more carbon in the soil relative to the one below.
A quick stop at Secrest Arboretum to view the famous Dawn Redwoods. Under the proper conditions these trees can grow a meter each year. Our tree-ring data from this stand helps define the optimum conditions for their growth. Planting trees sequesters carbon and helps out in lots of other ways as well.
In addition to the no-till fields and trees at Secrest – there is a meteorological record that spans more than 120 years (note how Tom – far left, seems to be the only student listening to the instructor). These instruments have been keeping track of climate and we will use it to compare with our tree ring study. Our tree ring project asks the question: during the time of European Settlement in Ohio what were the climate conditions like? (precipitation and temperature) and could the widespread deforestation and tile and draining of the region have perturbed the climate (see this video for more on this subject). This question is relevant to the ever-present striving of climate scientists to investigate the relative roles of natural climate variability and anthropogenic change.