Coring the Bog – An 18,000 Year Record of Environmental Change

Two class projects kick off the Climate Change 2017 course. The first deals with tree-ring dating (dendrochronology, blog post coming soon) of historical structures and then analyzing the tree-rings for their climate significance. The second is is shown below and it concerned with analyzing sediment cores from Browns Lake Bog that document climate variability since the last Ice Age. Below are some photos of the bog coring – great thanks to Dr. Tom Lowell and his Glacial Geology class from the University of Cincinnati – the folks who did most of the work.

Setting up the coring rig at Browns Lake – early in the day snow covered the ground by 4 pm it was gone (albedo feedback in play).

The core boss (Dr. Tom Lowell) oversees the extraction of another meter of mud from the bog.

The probing team sends down 7 rods through the mud until refusal. Mapping the mud thickness gives an idea of the geometry of the bog and allows for the construction of an isopach map.

Extracting peat – the upper 5 meters or so are peat (significant amount of sphagnum moss and carbon). Note the trees, it is not a sphagnum bog now here.

Setting up the production line and assigning teams and tasks.

Coring a tree to determine the recruitment time – the hypothesis is that these trees moved into the bog recently (past 200 years) – the first trees here since the Ice Age. This nutrient limited bog was fertilized by wind blown dust during European Settlement allowing these vascular plants to obtain a foothold in the previously sphagnum moss dominated bog.

Hey there is a Wooster student – good job Ben. This white oak is growing on the top of  a kame and it has witnessed the changes in the climate and land use for the last 300 years.

Nick samples the bog water for its isotopic composition. This is work done in collaboration with isotope geologists at the University of Cincinnati.

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5 Responses to Coring the Bog – An 18,000 Year Record of Environmental Change

  1. Mark Wilson says:

    Nice work. Interesting hypothesis about the trees and post-settlement recruitment.

  2. J D Draves says:

    This Wooster parent presumes that the climate history is revealed through the change in the preserved plant composition in the sediment since the bog environment is oxygen starved

  3. Bill Reinthal says:

    Mr./Ms. Draves, the researchers would look at plant composition, usually from the pollen grains left behind, depending on how easily they can determine the stratigraphy or “layering,” age-wise, of the sediments in the cores. Bogs, like these, can be difficult, stratigraphically, because they fill in both from the bottom, upward, and from the sides, inward, making the age relationships more complicated.

    They also look at the carbon, hydrogen, and oxygen stable isotopes from organisms’ remains, because both natural physical processes (like temperature change), and, particularly, biological processes fractionate (separate the different weights of different isotopes–e.g., biological systems use lighter isotopes in preference to heavy isotopes, when compared to the abundances in the natural environment, because they are “energetically” easier to use) very efficiently, giving us clues about ancient environments.

  4. Pingback: Coring the Bog – An 18,000 Year Record of Environmental Change | COW Tree Ring Lab

  5. Pingback: AMRE at Brown’s Lake Bog | College of Wooster Tree Ring Lab

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