The Madison-Hills Paleoecology Project ("MPEP")

Introduction

The MPEP is a privately funded endeavor that will drill and sample the layers of soft sediment that have accumulated in the deepest part of Big Pea Porridge Pond ("BPPP") in Madison, New Hampshire during the past +/- 14,000 years. The purpose of the work is to scientifically analyze, technically describe/catalogue, and radiocarbon/proxy date these progressively deposited materials to establish the ecologic change-sequence history of the Pond's basin since the departure of the last ice sheet. The work described above will begin in late January or early February 2008 and be completed by late Spring or Summer 2008.

Scientific Basis of the MPEP

Lake-bottom sediments represent the most continuously detailed records of post-glacial (Pleistocene to Holocene) climate and environmental change available, and such records provide the best long term context for the dramatic physical and biological/ecological changes that have occurred during what has become to be known as the "Anthropocene" period (time since the beginning of extensive human habitation).

Who's Involved

The scientific staff of MPEP includes the following individuals, all of whom are donating their professional expertise to the project:

P. Thompson Davis, Ph.D., Dept. of Natural & Applied Sciences, Bentley College.
Brian Fowler, Quaternary Scientist, Project Director.
Lee Pollock, Ph.D., Dept. of Biology, Drew University.
Lisa Doner, Ph.D., Center for the Environmental, Plymouth State University



Monday, July 14, 2008

Scientific Information Posting No. 17

Splitting the Cores

Sorry to offer this posting a little out of order. With all the flurry of follow-up investigation of material sampled from the core, we neglected to offer a glimpse of the core splitting session itself.

A group of us met at Plymouth State University on Saturday, May 3 to begin the process. To start with, we retrieved the deeper core segments from the 4 C coldroom where they had been stored since the original sampling date. The foil and cling wrap covering of the core segment was carefully unwrapped and details regarding its appearance and texture were noted.




Then the segment was split longitudinally into halves to reveal the interior material.
Having laid a tape measure along side it, we photo-documented the segment and, using a standard soil color chart, we noted its appearance before subtle color tones could change as these sediments were exposed to air for the first time in thousands of years.



Most core segments (such as the one below) have a brownish-gray appearance produced by the remains of biologically produced organic materials (plant, animal, and microorganismal remains) mixed with inorganic mineral materials. Brownish organic deposits in lake bottoms is known as "gyttja" (a Swedish word, pronounced "yit-yah").



Then at specific depth intervals along the core, subsamples of sediment were extracted for detailed analysis. All subsamples were removed from one side of the split core so that the opposite side could be stored intact for archival purposes. Subsamples taken






will be examined for the remains of midge larvae (or chironomids – useful in reconstructing past temperatures), pollen (useful in reconstructing a picture of changes in the surrounding landscape), the degree of sediment compaction (useful in analyzing the impact of overlying geological forces) and organic content (using a "loss on ignition" or LOI technique – useful in characterizing changes in overall biological productivity over time). The significance of each of these studies will be presented as results become available in the months ahead.

As we had seen in the field, in the 11th segment we collected, a dramatic change in appearance was noted between the brownish (gyttja) sediments and the gray mineral silts that apparently lack such organics. The illustration below shows that transition point between 23 and 24 meters below the Pond surface. A subsample of sediment from this transition point was used for dating purposes (described in Scientific Posting 16).




Click on this image for short slideshow of larger images!




Lee Pollock

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