Loyola University Chicago

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Professor Department of Natural Science Ph.D. 1989, University of Louisville Aquatic Ecology. Phone: 773.508.2950 E-Mail: cpeters@luc.edu

RESEARCH INTERESTS

My research focuses on understanding how the structure, dynamics, and function of attached microalgal communities, the primary transducers of sunlight energy in aquatic systems, vary with spatial and temporal change in chemical, physical, and biological attributes of the environment. Because of their small size and rapid turnover, algal communities are an ideal model system for addressing general ecological questions. Within a week of development, microalgal communities can support >1 million cells/cm2 of colonization surface and contain dozens or even hundreds of species that differ widely in growth habit, resource requirements, and susceptibility to removal by physical disturbance or ingestion by grazing macro- or microinvertebrates, fish, or amphibians. Because algae are microscopic, cells residing within developing algal mats experience significant changes in availability of light or dissolved nutrients as communities thicken; successional processes are driven by these internal changes. Community attributes at any given time are a product of the interaction between these internal factors and external factors such as the density and identity of grazers, heterogeneity in nutrient supply, variation in current regime, and the timing and magnitude of physical disturbance events.

Stream ecosystems are both spatially and temporally heterogeneous. Their nutrient content varies with land use or geology within a catchment, or the strength and pattern of hydrologic exchange between groundwater and surface water. Patterns of groundwater/surface water exchange vary among years with snowpack or volume of rainfall, which also influence densities and identity of organisms that consume algae. Environmental variation from these and other sources influences the species composition, biomass, and physiological condition microalgal communities. My primary goal is to equate the sensitivity of algal community attributes to environmental variation, and ultimately to assess whether variation in algal communities induced by such changes influences the ecological functioning of stream ecosystems.

REPRESENTATIVE PUBLICATIONS

ISHIDA, C. A., S. ARNON, C. G. PETERSON, J. J. KELLY, & K. A. GRAY (in press) Influence of algal community structure on denitrification rates in periphyton cultivated on artificial substrates. Microbial Ecology

ARNON, S., C. G. PETERSON, K. A. GRAY, & A. I. PACKMAN (in press) Influence of flow conditions and system geometry on nitrate use by benthic biofilms: Implications for nutrient mitigation. Environmental Science & Technology.

ARNON, S., A. I. PACKMAN, C. G. PETERSON, & K. A. GRAY. (2007) The effects of overlying flow velocity on periphyton structure and denitrification. Journal of Geophysical Research - Biogeosciences. 112: G01002

PETERSON, C. G. (2007) The Ecology of Non-Marine Algae: Streams. Pages 434-558 In: (T. Orchard, J. Huisman, & T. Entwisle, eds.) The Algae of Australia. Australian Biological Resources Study, Canberra.

Peterson, C. G., and T. L. Jones (2003) Diatom viability in insect feces: comparison between two benthic species, Achnanthidium lanceolatum and Synedra ulna. Hydrobiologia 501:93-99.

Peterson, C. G., M. Horton, M. C. Marshall, H. M. Valett, & C. N. Dahm (2001) Spatial and temporal variation in the influence of grazing macroinvertebrates on epilithic algae in a montane stream. Archiv fur Hydrobiologie 153:29-54

Peterson CG, Valett HM, Dahm CN, 2001. Shifts in habitat templates for lotic microalgae linked to interannual variation in snowmelt intensity. Limnology Oceanography 46:858-870.

Peterson, C. G. and A. J. Boulton. (1999) Stream permanence influences microalgae food availability to grazing tadpoles in arid-zone springs. Oecologia 118:340-352.

Peterson, C. G., K. A. Vormittag, and H. M. Valett. (1998) Ingestion and digestion of epilithinc algae by larval insects in a heavily grazed montane stream. Freshwater Biology 40:1-17

Peterson, C. G. 1996. Mechanisms of lotic microalgal colonization following space-clearing disturbances acting at different spatial scales. Oikos 77:417-435

Peterson, C. G. 1996. Response of Benthic Algal Communities to Natural Physical Disturbance. Pages 375-402, In (R. J. Stevenson, M. L. Bothwell, & R. L. Lowe, editors) Algal Ecology: Freshwater Benthic Ecosystems. Academic Press, San Diego.

 
Fig. Mean sample scores (? 1 SE) along DCA ordination axes defined by relative biovolume of common algal taxa in epilithic samples collected from upstream and downstream study reaches in Rio Calaveras, NM during study periods 1995, 1996, and 1997. Initial, pre-snowmelt samples are denoted with plus sign (+). Species loadings for taxa used in the analyses are given in the right panel, with the dashed rectangle delimiting the extent of axis scores from sample plots. Variation among sample points on ordination plots reflects differences in algal community structure.