Marine mammal and ecosystem health
Marine mammals are exposed to a plethora of anthropogenic stressors and an increasing stress burden can significantly affect the health of marine mammals at both the individual and population level. Stress is commonly associated with effects such as impaired immune function and reproductive impairment. Of these stressors, marine mammals are particularly sensitive to contaminant exposure. Many of these toxic compounds are highly persistent and fat soluble, tending to accumulate in marine mammal blubber over time. Additionally, contaminants biomagnify resulting in higher contaminant exposure levels in higher trophic level animals. As such, contaminant related health assessments of marine mammals not only aid in species-specific conservation but also indicate broader ecosystem health by acting as an early warning signal for lower trophic level organisms. This research project aims to assess both marine mammal and ecosystem health by identifying novel contaminants to which marine organisms are exposed and determining potential health risk through the use of molecular biomarkers.
Identification of Novel Contaminants
In the past, contaminant studies have been limited to examining one or a few contaminants at a time. While this can be helpful in targeting specific compounds of interest, these studies do not take into account the magnitude of different contaminants present in the environment nor can they identify contaminants of emerging concern (CECs). By employing a novel, non-targeted approach to contaminant analysis we can gain a better understanding of the range of contaminants to which marine organisms are being exposed. We will be conducting non-targeted contaminant analysis on marine mammals in the Southern California Bight to characterize the contaminants present in the region. This technique is a more proactive approach to contaminant analysis that will allow for the detection of CECs before they reach dangerously high levels in the environment.
Contaminant-Related Health Assessment in Marine Mammals
In addition to measuring total contaminant exposure it is important to understand how these compounds can negatively affect marine mammal health. Health assessment is a vital component to monitoring marine mammal populations and informing management actions. Furthermore, compounds that are toxic to marine mammals are likely a threat to human and ecosystem health as well. Many contaminants are endocrine disruptors in both marine mammals and humans. To address this we will combine contaminant analysis with the measurement of endocrine biomarkers in marine mammal blubber. This technique has proven to be a robust diagnostic tool capable of diagnosing pregnancy in wild marine mammals and will provide a means of assessing endocrine changes associated with contaminant exposure.