Professional History. As an undergraduate at Lehigh University, I completed two summer internships with Dr. Craig E. Williamson studying the phototaxis and diel vertical migration of freshwater zooplankton in response to ultraviolet radiation (UV), food limitation, and kairomones from fish and the invertebrate predator Chaoborus in the field. This research led to a publication in Oecologia. My experience out in the field encouraged me to conduct independent research in the lab on the relative importance of UV on the depth selection behavior and phototaxis of freshwater zooplankton, which eventually led to an honors thesis. Recently, I received my M.S. from Miami University under the guidance of Dr. Mike J. Vanni. My thesis research focused on the effect of species identity on the stoichiometry of fish nutrient excretion. I am currently a first year Ph.D. student with Dr. Vanni studying consumer-driven nutrient cycling and ecological stoichiometry theory.
Research Interests. Within the field of aquatic ecology, I am most interested in the area of consumer-driven nutrient cycling, especially in relation to ecological stoichiometry theory. Ecological stoichiometry theory, or the balance of energy and materials in ecological interactions and processes, has emerged as a conceptual framework for addressing questions about how biodiversity can influence nutrient cycling in aquatic systems. Loss of particular species or trophic groups could change nutrient cycling rates and ratios (i.e. stoichiometry) within an ecosystem, possibly leading to alterations in phytoplankton productivity and community structure and eventually influencing other trophic levels. As a masters' student, I found that variation in fish nutrient cycling rates (i.e. excretion rates) among species within the same reservoir could not be fully explained by fish body nutrient content, which is contrary to one of the fundamental predictions of stoichiometry theory regarding consumer-driven nutrient cycling. In fact, we found that diet may actually be driving fish nutrient excretion (specifically, N:P ratio excreted) more than body nutrient content. Thus, for my Ph.D., I will investigate how the diet of fish can influence their body nutrient content and, in turn, their excretion rates and ratios. I also intend to study how stoichiometry influences nutrient cycling in more diverse systems and how it is in turn affected by phylogenetic constraints. Knowledge of the effects of species identity and abundance on nutrient cycling within the context of ecological stoichiometry theory could aid resource managers in mitigating eutrophication in aquatic systems, thereby protecting biodiversity and human quality of life.
Professional and Career Goals. It is my hope to extend ecological stoichiometry theory to new areas in ecology such as evolutionary and physiological ecology. For example, I am currently working on a side-project studying the possible effect of organismal stoichiomety on the performance and mating systems of fiddler crabs. In terms of my career goals, I intend to pursue a tenure track position at a university, possibly working on fish stoichiometry, nutrient cycling, and biodiversity issues in the tropics.
Publications.
Torres, L.E. and M.J. Vanni. In review.
Stoichiometry of nutrient excretion by
fish: Interspecific variation in a
eutrophic lake. Ecology.
Leech, D.M., W.J. Boeing, C.E. Williamson, S.L.
Cooke, and L.E. Torres. In review. UV
radiation facilitates fish predation on
zooplankton in UV-transparent lakes.
Ecology.
Boeing, W.J., C.E. Williamson, D.M. Leech, S.L.
Cooke, and L.E. Torres. 2004. Damaging
UV radiation and invertebrate predation:
conflicting selective pressures for
zooplankton vertical distribution in the
water column of low DOC lakes. Oecologia
138: 603-612.
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