Meeting Abstract
The hypoxic response consists of many genetic, metabolic, and cardiovascular changes that interact to balance oxygen supply and demand in order to increase survival. In Danio rerio, this response consists of changes in parameters like stroke volume, heart rate, red blood cell (RBC) velocity, hematocrit, and metabolic rate. Anthropogenic stressors like pollutants can interact with these parameters and thus affect how the cardiovascular system responds to hypoxia. The endocrine disruptor, bisphenol A (BPA), and the oil spill contaminant, phenanthrene, a polycyclic aromatic hydrocarbon (PAH) were used in co-exposure experiments with hypoxia in eggs and larvae. Cardiovascular parameters were measured using video microscopy and digital motion analysis. We found that bisphenol A had little effect on cardiovascular parameters when exposed singly, but when in combination with hypoxia resulted in large decreases in heart rate and cardiac output in addition to RBC velocity. Exposure to phenanthrene singly resulted in decreases in stroke volume, heart rate, and RBC velocity. These decreases were exacerbated when co-exposed with hypoxia. In addition, yolk size was smaller with single exposure to phenanthrene but it was larger in co-exposed embryos indicating that phenanthrene and hypoxia exposure have opposing effects on yolk consumption and possibly metabolic rate. The effect size was also influenced by the age of the larvae indicating that the developmental stage of the cardiovascular system at exposure plays a role. Both bisphenol A and phenanthrene exposure resulted in higher mortality rates when in combination with hypoxia. This research supports the hypothesis that pollutants can affect how aquatic organisms respond and survive during hypoxic events.
