High School manoomin Students Study at LacCore Labs

By , August 21, 2010

During the week of Aug 2-6 manoomin students and teachers from the Cloquet area worked with scientists and grad students at the University of Minnesota’s LacCore Laboratory testing the cores collected from the Fond du Lac Reservation last winter. During the months of January, February and March teams work with the Natural Resources to collect cores in preparation for further this additional study.

Students looked for pollen (pine, birch,etc.), phytolyths, diatoms, and macro-fossils (plants). Much of their time was spent looking carefully at the “mud” taken from the collected core with their eyes and through a microscope. Deductions were made by the students with the Scientists to determine what the land was like in the past.

Students also spent time an enjoyable time at the Frank Theatre doing improvisational theatre and original writing. One day was spent enjoying the the Walker Sculpture Garden and the Como Zoo.

A Scientific poster reflecting year one’s study of the wild rice lakes was on display at the Geo-Science Alliance Conference at the Black Bear Casino, Sept 16-18, 2010, at the Fond du Lac Tribal and Community College – gidakiimanaaniwigamig office and Biology Dept, the Ojibwe School Special Education Dept., ISD 2142 American Indian Student Services and the AlBrook (now South Ridge) Science Department.

Mini-REU Abstracts

By , August 4, 2010

DIATOMS

For the diatom analysis we focused on the sediment cores from Perch Lake; two samples were analyzed near the surface of the core (representing recent conditions) and three samples were analyzed from deeper sediments (representing approximately 3,000 years before present).   Diatoms were identified to genus and also grouped as benthic or planktonic.  Benthic diatoms live on the lake bottom, attached to sediments or aquatic plants, planktonic diatoms live suspended in the water column.  Since diatoms are photosynthetic, a low of benthic diatoms indicate the lack of light penetration to the lake bottom which would indicate turbid conditions.  Our first four samples were dominated by benthic Fragilaria species; these species tend to dominate shallow lake systems and can live either attached to bottom substrates or suspended in the water column.  We found the largest shift in diatom species assemblage between 319 cm and 379 cm sediment depth.   In the bottommost sample, there was decrease in benthic  Fragilaria and an increase in Navicula and Achnanthes species, as well as in the planktonic genus Cyclotella.  This suggests that water level may have been deeper at this time, due to the presence of the benthic genera Navicula and Achnanthes as well as the increase in the plantonic diatom species.

POLLEN

Why is pollen so important to our community? We found pollen in lake sediments from 10,000 years ago to the present time. We found a high abundance of spruce pollen at 600 to 700 cm, around the time the lake was first formed after the glaciers melted. This was followed by a high abundance of red-jack pine pollen from 425 to 700 cm. White pine pollen increases about 550 cm, estimated to be about 7000 years ago. Dates are estimated pending radiocarbon dates. There is a decrease of red-jack pine and an increase of white pine during the last ~4000 years.  This increase in white pine is usually thought to be caused by a change to cooler or wetter climate. Another interesting change is the increased abundance of grass pollen in the last several thousand years. Wild rice is a grass and this could represent an increase in wild rice abundance in the lake, but its pollen cannot be distinguished from other grasses so it is not clear what type of grass increased. Our data show that the forests of the region have change a lot over thousands of years and raise many questions about the role of climate and native people in these changes.

Macrofossils

The results from the macrofossil analysis of Perch lake core 1C show the development of the aquatic and terrestrial vegetation since the last glaciation. Needles of spruce in the oldest sediments indicate the late glacial spruce stands around the lake. In the same period, the aquatic vegetation was represented by slender naiat (Najas flexilis) and pondweed (Potamogeton sp.). Seeds of birch and needles of pine between 600 and 350 cm indicate the arrival of these trees around the lake. In the littoral zone, spikerush (Eleocharis sp.) and common cattail (Typha latifolia) appeared. High amounts of seeds from slender naiat and pondweed between 250 and 350 cm indicate most probably a change from oligotrophic to mesotrophic conditions in the lake. However, after this change occurred, the amount of seeds from the slender naiat and pondweed has decreased. In addition to this, macrofossils of Chara sp. and Bryales sp. have been found in the sediment between 150 to 0 cm.

The top 90 cm of core 1A from Rice Portage lake were studied for macrofossils in order to determine whether or not wild rice (Zizania sp.) was present in the past. Our results show macro-remains of wild rice between 30 and 60 cm. Macrofossils of pine, spruce, birch, johnswort, common arrowhead, rush, sage, pondweed, slender naiat, and aquatic mosses were found as well.

Phytoliths

The glumes (seed cases) of different grasses produce different assemblages of phytoliths. Phytoliths are silicon-dioxide accumulating cells found in all grasses. Phytoliths were recovered from glumes of zizania palustris from several localities: Perch Lake, Koochiching County, St. Louis County, and Hubbard County. A river rice sample was obtained from Clay County. A sample of Zizania aquatic was collected from Ohio, and Zea mays from North Dakota. The method we used to describe the phytholith assemblages was initially developed by Dr. Susan Mulholland, and refined by Dr. Thompson. This method consisted  of: taking images of the phytoliths, identifying the phytolith physical structure, measuring the structure, entering data from each sample (50 phytolith forms each)  and combining into a database allowing comparison of the samples. A program called PAST was used for statistical analysis. We used principal components analysis, multi-dimentional scaling, and cluster analysis to determine the differences between the samples. We saw that Z. palustris aquatic, and Zea mays each produced different assemblages of phytoliths. This establishes the utility of this method to identify wild rice from sediments or other contexts.

Jobs to think about…..

By , August 3, 2010

Does your work in the manoomin project encourage you to look towards a job in Natural Resources (Natural Resource folks watch over the earth, water and air for a healthy future. See FDL Natural Resources site by clicking here.

Panorama Theme by Themocracy