Environmental toxicology

Persistent, anthropogenic contaminants collectively known as endocrine-disrupting chemicals (EDCs), are considered to be potential threats to wildlife reproductive fitness (Wingfield, 2002). The modes by which EDCs act on the reproductive system, and establishment of steroid profiles in wildlife, are important areas of study. Two means of performing an endocrine snapshot profile from dolphin tissues (serum and urine) were tested on samples, comparing a novel high performance liquid chromatography method to newly-validated enzyme-linked immunoassays (ELISAs). Serum and urine samples were obtained from two marine parks, and from free-ranging dolphins in the Indian River Lagoon (IRL) and Charleston Harbor (CHS) systems. Relative binding affinities of steroids versus putative EDCs to steroid receptors were compared in dolphin reproductive tissues, obtained by the Georgia Aquarium's Dolphin Conservation Field Station (GADCFS) from strained bottlenose dolphins (four male, three female) during 2010 and 20ll.........I conclude that endocrine disruptors are tissue and receptor specific, and both legacy and emerging contaminants are of concern to dolphin stocks, particularly those facing other significant environmental stressors.

Cyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH <7 are suggested by significantly greater expression of myxoxanthophylls. Direct and indirect physiological costs of altering cell walls may contribute to S. calcicola's depressed growth at acidic pH. Comparison of chlorophylls expression suggests that alkaline rather than neutral external pH is only beneficial for S. calcicola growth in absence of nutrient limitation. While the cyanobacterial biomarker ratio of chlorophylls to echinenone was stable across the pertinent pH range of 6-8, other pigment ratios in S. calcicola were affected by pH with an approximately two week lag between the change of pH and the corresponding change of pigment expression.