NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Seasonal Variation of Total Mercury Burden in the American Alligator (Alligator Mississippiensis) at Merritt Island National Wildlife Refuge (MINWR), FloridaSeasonal variation of mercury (Hg) is not well studied in free-ranging wildlife. Atmospheric deposition patterns of Hg have been studied in detail and have been modeled for both global and specific locations with great accuracy and correlates to environment impact. However, monitoring these trends in wildlife is complicated due to local environmental parameters (e.g., rainfall, humidity, pH, bacterial composition) that can affect the transformation of atmospheric Hg to the biologically available forms. Here, we utilized an abundant and healthy population of American alligators (Alligator mississippiensis) at Merritt Island National Wildlife Refuge (MINWR), FL, and assessed Hg burden in whole blood samples over a span of 7 years (2007 2014; n 174) in an effort to assess seasonal variation of total [Hg]. While the majority of this population is assumed healthy, 18 individuals with low body mass indices (BMI, defined in this study) were captured throughout the 7 year sampling period. These individual alligators exhibited [Hg] that were not consistent with the observed overall seasonal [Hg] variation, and were statistically different from the healthy population of alligators. The alligators with low BMI had elevated concentrations of Hg compared to their age/sex/season matched counterparts with normal BMI. Statistically significant differences were found between the winter and spring seasons for animals with normal BMI. The data in this report supports the conclusion that organismal total [Hg] do fluctuate directly with seasonal deposition rates as well as other seasonal environmental parameters, such as average rainfall and prevailing wind direction. This study highlights the unique environment of MINWR to permit annual assessment of apex predators, such as the American alligator, to determine detailed environmental impact of contaminants of concern.
Document ID
20160011977
Document Type
Reprint (Version printed in journal)
Authors
Nilsen, Frances M. (National Inst. of Standards and Technology Charleston, SC, United States)
Dorsey, Jonathan E. (Medical Univ. of South Carolina Charleston, SC, United States)
Long, Stephen E. (National Inst. of Standards and Technology Charleston, SC, United States)
Schock, Tracey B. (National Inst. of Standards and Technology Charleston, SC, United States)
Bowden, John A. (National Inst. of Standards and Technology Charleston, SC, United States)
Lowers, Russell H. (Integrated Mission Support Services, LLC Merritt Island, FL, United States)
Guillette, Louis J., Jr. (Medical Univ. of South Carolina Charleston, SC, United States)
Date Acquired
October 4, 2016
Publication Date
January 1, 2016
Publication Information
Publication: Chemsophere
Issue: 168
Subject Category
Life Sciences (General)
Environment Pollution
Report/Patent Number
KSC-E-DAA-TN35168
Funding Number(s)
CONTRACT_GRANT: NNK16OB01C
Distribution Limits
Public
Copyright
Other
Keywords
Hg
Alligator mississippiensis
Mercury