The Lab, Fall 2012
Rachael Heuer, John Stieglitz, Ilan Ruhr, Jenny Panlilio, Charlotte Bodinier, Kat Munley, Ed Mager, and Martin Grosell

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Post-Doctoral Fellows

Charlotte Bodinier  (cbodinier@rsmas.miami.edu)

My research is focused on the ecophysiology and the ecotoxicology of marine teleost species during their development. I am looking at the impact of abiotic factors such as salinity and/or pollutants on the development and on the physiological performance of marine species. Among other things, I am currently studying the physiological development of economically important marine finfish species by examining their ion and water regulation in different tissues from fertilization through the juvenile stage, using cellular and molecular approaches. I am also involved in ecotoxicological studies to assess the physiological impacts of acute exposure to polycyclic aromatic hydrocardons (PAHs) during the development of pelagic teleost species. Broadly speaking, the main aim of my research is to improve knowledge on the development of vital physiological functions in teleost species by following their ontogeny.

http://www.charlottebodinier.com/site/Home.html

Ed Mager (emager@rsmas.miami.edu)

My research is focused on examining the acute and chronic effects in commercially important pelagic fish species that result from exposure to polycyclic aromatic hydrocarbons (PAHs), the primary class of toxic agents released from oil.  Specifically, I intend to characterize the PAH concentrations that cause acute mortality during the most sensitive early life stages (i.e. embryonic and larval), as well as examine the long-term effects of PAH exposure by evaluating various physiological parameters.  Previous research has shown that PAHs affect cardiac development and may cause anemia.  These effects would likely impair the ecological fitness of fish populations by reducing swimming performance (e.g. by affecting migration, foraging and/or predator avoidance).  I intend to investigate the potential effects on swimming performance and aerobic scope using swim tunnel respirometery, and evaluate impairment to cardiac development utilizing in vivo microscopic morphometrics.

http://www.rsmas.miami.edu/personal/emager/

Ph.D. Students

Recent research has highlighted the formerly understated importance of marine teleost fish to the oceanic carbon cycle. My research interests lie in examining how projected ocean acidification levels will affect acid-base compensatory mechanisms in the gulf toadfish (Opsanus beta).  It has already been established that gastrointestinal HCO₃^- secretion is a vital component of the toadfish osmoregulatory process, a mechanism hypothesized to also play a role in acid-base balance. In my current research project, I am measuring concentration and rate changes of intestinal HCO₃^- secretion and rectal HCO₃^- excretion in toadfish exposed to elevated atmospheric carbon dioxide concentrations predicted for the end of the current and next centuries. I am also interested in quantifying changes in carbonate precipitate formation rates, dissolution potential and carbonate chemical composition as a result of hypercapnia.

My research focuses on aquaculture, physiology, and toxicology. I am investigating the effects of crude oil and chemical dispersants on economically important finfish species of the Gulf of Mexico, using aquaculture to gain insight into acute toxicity and sub-lethal physiological effects of these toxins on the early life stages of marine fish. As part of this research, I am working to develop sustainable aquaculture techniques and technology for use in hatcheries and offshore aquaculture sites, with specific focus on pelagic species such as tuna (Thunnus spp.), mahi-mahi (Coryphaena hippurus), cobia (Rachycentron canadum), goggle eye (Selar crumenophthalmus), and Florida pompano (Trachinotus carolinus) in an effort to further develop these species for use in marine finfish aquaculture and aquatic toxicology.

Marine fish face a suite of physical factors that affect their everyday lives. Most important of these is the high salt content of the oceans and because of this obstacle, fish must not only prevent the loss of water to their environment, but also absorb it efficiently into their bodies. In my research, I study how the effects of osmoregulatory challenges in the toadfish (Opsanus beta) intestine affect their ability to regulate ions and absorb water. I focus on guanylin and uroguanylin, a family of intestinal peptides, which activate the opening of intestinal chloride channels via a receptor-mediated cascade. This mechanism allows chloride ions (and bicarbonate ions) to exit the intestinal cell and enter the lumen of the intestine. The purpose of this study is to determine how guanylin and uroguanylin are transcriptionally regulated when environmental salinity changes. Further experiments will test the effects of varying pH levels in situ on the capability of toadfish to withstand different environmental salinity regimes.

Undergraduate Students

My research focuses on the toxicity of metals to the freshwater pond snail, Lymnaea stagnalis.  Previous studies have established L. stagnalis as the most sensitive aquatic species tested to date for Cu and Pb based on 30-d experiments evaluating juvenile snail survival and growth.  Despite this high sensitivity, the effects of metals on L. stagnalis when exposed over the full life cycle of the animal are unknown.  I am currently investigating the effects of Pb on L. stagnalis in a full life cycle study that will begin with newly hatched snails and evaluate survival, growth, and reproduction as well as survival and growth in the F₁ generation.  My goal is to pinpoint the time during its life cycle at which L. stagnalis is most sensitive to Pb.  I hope to continue studying these organisms in the future and use my research to formulate an undergraduate senior thesis.

My project involves understanding respiration in a fresh water snail, Lymnaea stagnalis, which breathes in both air and water. The rate of oxygen consumption from air is expected to be partially dependent on the surface-area-to-volume ratio of the snails. Smaller snails with higher surface-area-to-volume ratios are predicted to have lower aerial respiration rates because oxygen can more easily be obtained by diffusion from the water owing to the larger relative surface area. However, smaller organisms have higher metabolic rates per unit body weight than larger organisms. This indicates that smaller animals have comparatively higher respiration rates. Thus, there are two competing effects for size-dependent respiration. I am teasing these effects apart by measuring respiration rates of snails at various sizes in both air and water and determining at what snail mass is one effect possibly more dominant than the other.