David O. Norris - US grants

The acquisition of a radiation counting system will be utilized to further research in several areas including: steroid metabolism and its effects upon reproduction; the role of biogenic monoamines in metamorphosis regulation of glucose metabolism in premuscle of fasted and fed animals; regulation of the quiescent, resting states during the life cycles of invertebrates; and metabolic pathways involved in C3-C4 intermediate photosynthesis.

The vertebrate neuroendocrine system, using information derived from both internal and external environments, controls development, growth, and reproduction. The brain integrates this information and secretes neurotransmitters and neurohormones to alter pituitary function and bring about endocrine based events and behavioral changes. Such changes are very important in mediating major life events that help animals adapt to environmental changes. Because of the varied modes of reproduction that exist in teleost fishes, fishes are a useful system to look at how both the internal and external environments influence sex determination and sexual behaviors. One particularly useful mode of reproduction is a sexual plasticity known as sequential hermaphroditism where an individual can begin life as one sex, reproduce as that sex for at least one breeding season and subsequently undergo sex reversal and reproduce as the opposite sex. Such a change is accompanied by drastic changes in behavior. This system allows for investigation into the role of the brain in sex determination and sex-specific behavior. The purpose of the proposed research is to identify changes in monoamine neurotransmitters in the brains of a protogynous coral reef fish (Thalassoma duperrey) throughout the process of sex reversal and in relation to daily, semi-lunar and annual influences. Because there are relatively few vertebrates that exhibit a natural sex reversal once sexual maturation has been achieved, this system is an excellent model in which to look at changes in behavior and neurochemistry that accompany sex reversal and possible control mechanisms for such a reversal. This work will contribute to a better understanding of the relationship of neural control mechanisms for sex specific behaviors. By using animals which can act as both sexes in one individual at different times in the life history, one can gain a better understanding of how changes in sexual behavior may be controlle d in other animals, including humans. In addition the presence of diandry (two different male phenotypes, one being a male throughout the life history and the other being first female and then male) offers the opportunity to compare behaviors of two different types of males. The proposed work will provide information on the changes in monoamines associated with sex reversal and accompanying behavioral changes as well as some insights into possible cause-effect relationships. This system provides a unique opportunity for the study of neural correlates of sex determination and sexual behavior.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."
CBET- 0854527
Ryan, Joseph
University of Colorado at Boulder

Endocrine-Disrupting Compounds in a Rocky Mountain Stream: Effect of a Major Wastewater Treatment Plant Upgrade


The multidisciplinary research team assembled for this proposal will apply an integrated chemical, biological, and hydrological approach in field and laboratory studies to investigate the relationships between nutrient loading, endocrine-disrupting compound release, and perturbations in the stream ecosystem and endocrine function of aquatic organisms. Joseph Ryan (University of Colorado), Larry Barber (U.S. Geological Survey), and graduate research assistant Jeffrey Writer will evaluate the fate and transport of a suite of endocrine-disrupting compounds in Boulder Creek. David Norris, Alan Vajda, and a graduate research assistant (University of Colorado) will experimentally evaluate the interaction between nutrient and EDC load on fish reproduction and periphyton communities using an innovative on-site mobile exposure laboratory. The team will collaborate to examine the effects of the changes in endocrine-disrupting compound and nutrient loading using in-stream analyses of aquatic bio-criteria indicative of ecosystem function. These integrated analyses will elucidate the role of engineering upgrades in sustainable watershed management.

The intellectual merit of the proposed research is increased understanding of the role of wastewater treatment in the preservation of human health and ecosystem function. Determination of the processes governing fate and transport of endocrine-disrupting compounds will elucidate and facilitate engineering and watershed management efforts to mitigate detrimental impacts on aquatic ecosystems. This unique and timely opportunity to evaluate the effect of a wastewater treatment plant upgrade on nutrient and endocrine-disrupting compound loading and ecosystem response will help water managers evaluate the efficacy of engineering solutions designed to restore environmental systems and protect water resources.

The broader impacts of the proposed research include dissemination of the results by a variety of means to training of new researchers in an important interdisciplinary area of environmental engineering. The principal investigators have been and will continue to participate in a wide range of community and watershed organizations to provide access to the results of this study, including the Boulder Creek Watershed Initiative, the Boulder Area Sustainability Information Network, the Watershed curriculum, the Colorado Riparian Association, and associated forums and workshops.