Tuesday, April 16, 2013

Students tackle senior thesis research

Three students outlined their senior thesis proposals recently.

Melissa Dick
Melissa Dick's research is titled "Rapid Carbon Assessment of the Matanuska Valley using a Portable VNIR Spectrometer."

Her summary: Soil is the most basic and valuable resource for food, economy and ecology. An accurate assessment of carbon is important for nutrient management and carbon sequestration. Lab analysis is expensive and requires extensive soil sampling. Visible Infrared Spectroscopy (VNIR) is inexpensive and fast. The USDA-NRCS has calibrated VNIR techniques for a range of lower latitude soils. All latitudes need to be quantified and monitored. Understanding changes in land use could cause decline in carbon in soils. Loss of carbon contributes to atmospheric carbon dioxide.

Understanding current soil carbon levels is important for cold region soils to understand loss through land changes, agricultural management and future conservation plans.

Dick's objectives are to develop a reliable, quick VNIR method to test soil carbon in cropland and forest soils in the Matanuska Valley. It will require a method that can be easily used on local farms or regional levels and produce soil quality assessments for land management plans or decisions.

Dick said there is a growing body of literature on the use of VNIR spectroscopy to rapidly and inexpensively characterize soil for carbon content. Zhoa et al (2012) found that spectroscopy has demonstrated its capability to determine SOC content in the laboratory and in the field with a portable spectrometer.

Spectroscopy is rapid, timely, less expensive, non-destructive, straightforward and sometimes more accurate than conventional analysis (Rossel et al, 2005).

She will collect soil samples from pre-selected cropland and forest land, digging a soil pit at each site and sampling at intervals representing soil genetic horizons. Samples will be kept in a cool field moist state, scanned with a portable spectrometer and measured by dry combustion method. Results will be compared by VNIR spectra and LECO results, soil types and management practices. LECO results will be calibrated to VNIR readings using some statistical techniques: least square regression analysis, predictive equations or pedo-transfer function. Results will be put in an Excel format.

Katie Shink and Jacob Hakala

Katie Shink's title is: "Habitat Assessments and Relative Abundance of Lamprey Ammocoetes (Lenthenteron spp.) on the East Fork Andreafsky River, Alaska."

The summary: Lampreys are jawless, vertebrate fish existing on the Kenai Peninsula to the Arctic Coast and in the Yukon, Kuskokwim and Tanana River drainages. Two spescies occur on the Yukon River drainage: Arctic lamprey (L. camtschaticum) and Alaska brook lamprey (L. alaskensis). The project is significant because potential changes in ammocoete abundance have been detected. Shink would like to identify optimal habitat parameters and offer advice for management of commercial fishery and subsistence. Her objectives are to determine distributional gradient, identify optimal habitat zones and correlate habitat parameters to ammocoete abundance.

She anticipates a long-term monitoring effort that will reveal abundance increases toward the confluence and she expects a positive correlation between ammocoete abundance and dominant substrate. Sampling will be conducted in June and July, one site at the headwaters to the confluence of the Andreafsky River and the other around the weir site.

While lamprey are considered a nuisance species in the Great Lakes, they aren't necessarily the menace they are made out to be, Shink stated. They can grow as much as three feet long and sucker onto commercially valuable species. The population has been declining since 1997, Shink said. The meat is smoked and the skin is used for purses and other items. "I heard about a pilot study and I was interested to find out more about them," Shink said. "Initially I thought they looked like sea monsters."

Jacob Hakala's chose his topic, "Growth Rates of Siberian Larch in Interior Alaska," after studying two semesters in Sweden, where the tree grows prolifically. The Siberian Larch (Larix sibirica) is native to the taiga belt with a seed bearing age of 10 to 15 years. Larch has been a species of interest for reforestation in Alaska since the 1960s. There have been examples of 30 to 40-year-old mature trees with cones in Alaska. No study of larch's susceptibility to tree diseases in Alaska has been done. Larch seedlings suffer from moose browse more than native spruce.

While the economic value of larch in Alaska is unknown, in northern Europe the wood is used for railroad ties due to rot resistance. Up to 90 percent of the tree is heartwood and there is a thin cambial layer. It is known as the "tree of eternity." Very little research has been done in North America. Most studies deal with larch's response to climate change.

Hakala's objective is to determine if the growth rates of Siberian Larch are comparable to those of white spruce and lodgepole pine, allowing it to be considered for commercial production. He plans to provide the Division of Forestry with a description of production so the agency can determine what further research is needed and set up more plots.

His area of study will be three plots planted in 1989 in the Rosie Creek reforested area. One plot is 100 percent larch, one is mixed larch and lodgepole and one is mixed larch, lodgepole and spruce. Total acreage is 188. He will study the growth rate using Spencer tape, a wood core tool and the University of Georgia growth table. With calculated growth rates, foresters will be able to compare species.

The students will present their final papers by the end of fall semester.

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