NAU Facility Spotlight:
Colorado Plateau Analytical Lab

By Emily Litvack
Microbiology and Journalism, 2015

Nestled somewhat inconspicuously on the Northern Arizona University (NAU) campus in the Wettaw Biology and Biochemistry building is a set of five modest-looking labs, comprising the Colorado Plateau Analytical Lab (CPAL). While each laboratory under the CPAL umbrella engages in its own type of environmental research—from the carbon content of seeds to ash erupted from Alaskan volcanoes, all share a common function: to facilitate research and education at NAU and elsewhere.

Amino Acid Geochronology Lab (AAGL): As a National Science Foundation (NSF)-shared facility and one of only two such labs in North America, the Amino Acid Geochronology Lab receives more than a thousand samples collected by collaborators from across the globe every year. The lab analyzes amino acids preserved in fossils to interpret their geological age. The lab trains and employs graduate and undergraduate students who are enrolled in several degree programs at NAU. AAGL Director Darrell Kaufman says that scientists in fields ranging from anthropology to climate science require geochronological information to support their research.

Shell Sample

A shell sample is carefully bagged and numbered, so as to not be lost among the hundreds of others.

Currently, says Kaufman, the AAGL is focused on studies in historical ecology and Pliocene sea levels. During the Pliocene, about 3 million years ago, the global climate was 2 to 3°C warmer than today, about the same temperature that is expected as global warming progresses into the middle or end of the century. For the historical ecology studies, the AAGL analyzes hundreds of clams shells from the sea floor offshore of Australia, Brazil, California, and the Canadian Arctic islands to determine changes in the abundances of different species over thousands of years.

Analyzing racemization in amino acids—the process by which L-amino acids convert to D-isomeric configurations—is a fundamental technique in the AAGL. The ratio of D to L forms increases with time and temperature, allowing researchers to estimate the age of a specimen.

Environmental Analysis Lab (EAL): Much like the AAGL, CPAL's Environmental Analysis Lab analyzes samples for researchers; in fact, Ben Moan, a research specialist at the EAL, says this is the lab's primary function.

The lab specializes in environmental water chemistry. Through spectrophotometry, the EAL measures concentrations of nitrate, ammonium, and phosphate in organic samples, helping researchers and corporations monitor the overall health of ecosystems. This method allows for easy detection of contamination in water. The list of practical applications for this type of testing is long. For example, one can detect amounts of metals like calcium and sodium in plants, which affect growth. The EAL also measures isotope ratios in samples, which can then be used as an environmental indicator. For example, a species of protist, which exists in the ocean, incorporates two different isotopes of oxygen throughout its life. The ratio of these isotopes, oxygen 16 and oxygen 18, fluctuates with environmental changes, so when these organisms die, their shells can be used to infer changes in temperature or chemical composition of water over the course of time.

Mud Core Sample

A core sample of mud, taken from a volcano on Adak Island in Alaska, is analyzed.

Sedimentary Records of Environmental Change Lab (SRL): Staff members of the Sedimentary Records of Environmental Change Lab are putting present-day environmental changes into context by looking at the past. Because sediments are constantly forming new layers, they serve as a rare illustration of the planet's natural history. The SRL helps researchers answer questions about environmental changes, especially those that occur naturally (versus changes that may stem from human interaction.)

SRL staff members have been involved in many projects, such as interpreting how the environment around lakes changes over thousands of years by studying carbon/nitrogen concentrations in sediment core samples. One of the SRL's specialties is analyzing biogenic-silica content of lake sediment. Diatoms, a unicellular type of algae, have a cell wall made of the inorganic compound silica. When they die, their cell walls settle to—and collect at—the bottom of the lake. In the SRL, this silica concentration of the sediment is used as an environmental indicator. For example, an abundance of biogenic-silica in a lake might suggest high productivity in the overlying water.

In their own research pursuits, faculty and student members in the SRL collect samples that they distribute to collaborators in other fields. Kaufman says that lake sediments are an excellent focus for interdisciplinary research because they contain a vast assortment of things that can be analyzed, all arranged chronologically, going back thousands of years. In fact, the lab currently houses scores of samples Kaufman has collected over nearly 20 years of lake coring in Alaska.

Stable Isotope Lab (SIL): CPAL's Stable Isotope Lab prepares and analyzes a vast array of plant and animal samples for research projects at NAU, commercial companies, and government agencies. The SIL analyzes carbon, nitrogen, sulfur, and hydrogen isotopes using gas isotope-ratio mass spectrometers. It also offers training, the occasional demonstration for NAU courses, and sample preparation.

Preparing samples can be very involved and time-intensive, and the SIL employs NAU undergraduates to aid in this task. The fifth CPAL lab is a sample prep lab.

Although each laboratory has its specific focus, all five laboratories under the CPAL umbrella are an important part of advancing research and education at NAU through state-of-the art analytical equipment, research collaboration, training, classroom support, and the development of research methods.

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