Christine T. Oswald, Professor
Department of Biology
1250 Siskiyou Blvd.
Ashland, OR 97520
B.S. Biology, 1978, University of Illinois at Chicago
Ph.D. Biology, 1985, Indiana University, Bloomington
Comparative Animal Physiology (Bi314)
Advanced Animal Physiology (Bi414/514)
Principles of Biology (Bi211, Bi212, Bi213)
General Biology (Bi101, Bi102, Bi103)
I am currently studying the possible impact on wild mammals of a toxic metal, one that occurs naturally in high concentrations. Serpentine geologic formations, such as those found in southern Oregon and northern California, contain high levels of several potentially toxic metals, including nickel. These ecologically unique areas are home to many rare and specially adapted species of plants. Little is known about the animals that live in these areas, or their possible adaptations. My research will contribute to a better understanding of the ecology of these unusual areas, as well as to a deeper understanding of the effects, processing, and fate of metals in the body.
Because many plants in serpentine areas take up nickel from the soil, and may even concentrate it in their tissues, animals could ingest potentially harmful levels of nickel. In animals, the toxic effects of nickel exposure include cancer, liver, lung, and kidney damage, impairment of immune function, and abnormal reproductive physiology, among others. In spite of these toxic effects, several species of small mammals live in serpentine areas. Do they ingest nickel? Do they suffer any of the negative effects observed in other species? If so, to what extent? Or do they somehow avoid the negative consequences of nickel exposure? If so, how?
My results so far indicate that deer mice and wood rats do ingest nickel. It does not accumulate in most organs, but some individuals have unusually high levels of nickel in their reproductive organs (Oswald, 2004). Because harmful effects are a function of exposure dosage, and not just tissue burden, tissue levels of nickel do not provide enough information to determine the possible negative effects of living in serpentine areas. Several diagnostic blood tests indicate that deer mice may suffer from liver impairment, but do not have impaired kidney function, red or white blood cell production, or intestinal protein absorption.
Oswald. C. 2004. Gastrointestinal and tissue levels of nickel in deer mice Peromyscus maniculatus and wood rats Neotoma fuscipes from serpentine and non-serpentine areas. Acta Theriologica 49:419-426.
Oswald, C. 2011. Comparison of some blood parameters in deer mice (Peromyscus maniculatus) from serpentine and non-serpentine areas. American Society of Mammalogists.
Oswald, C., P. Fonken, D. Atkinson, and M. Palladino. 1994. Lactational water balance and recycling in white-footed mice, red-backed voles, and gerbils. J. Mamm 74:963-970.