Date of Award

8-2006

Degree Type

Thesis

Degree Name

MS Biology

Department

Biology

Advisor

Marian Glenn

Committee Member

Carolyn Bentivenga

Keywords

Chironomid hemoglobin, Genetic diversity, New Jersey, Hackensack Meadowlands, Wetlands, Biology, Environmental Indicators and Impact Assessment, Genetics

Abstract

Kearny Marsh located within the Hackensack Meadowlands is a freshwater wetland impacted by multiple environmental stressors from human activity. The marsh is located in the northeastern New Jersey metropolitan area. Chironomid larvae, aquatic larvae of midge fly, were analyzed from two Kearny Marsh sample sites, W9 and W22. A previous sediment analysis and toxicity study characterized heavy metal contaminants the marsh. The data results were applied in this thesis study to determine the correlation between environmental stressors and chironomid genetic diversity. Site W9 sediment was impacted by severe levels of total heavy metal contamination, whereas site W22 had just below to below effect levels of contamination. A primary thesis objective was to determine if chironomid hemoglobin genetic diversity is a suitable bioindicator of multiple environmental stressors. Prior to the genetic diversity evaluation, the thesis aim was to identify the genus of field chironomid with a molecular biomarker. SDS-PAGE gel electrophoresis was used to analyze hemoglobin protein band patterns. A molecular method was investigated because chironomid identification based purely on taxonomy is difficult, since the various chironomid species have similar morphological features. The hemoglobin protein measured by SDS-PAGE method demonstrated to be an appropriate identification method, because the hemoglobin protein band patterns, characterized by molecular weight and intensity, directly correlated with the respective head capsule morphology. Also, according to phylogenetic analysis with Hierarchical Cluster Analysis the three species evaluated: Glyptotendipes and Endochironomus clustered separately into two major clades. Chironomus and Glyptotendipes clustered separately within one major clade however diverged into two separate subclusters. These hemoglobin protein band patterns were applied to the genetic diversity study. The second objective was to determine if a correlation existed between multiple environmental stressors and genetic diversity. The thesis prediction was that a negative correlation exists between hemoglobin genetic diversity and heavy metal contamination, compounded by multiple environmental stressors. However, analysis of heavy metal concentration levels between the sample sites and Hb genetic diversity based on the SDS-PAGE gel band patterns indicated a positive correlation between Glyptotendipes hemoglobin protein diversity and heavy metal contamination levels. Site W9 with higher levels of total heavy metals had a greater Hb diversity level, in comparison to site W22 with lower levels of heavy metals. This result may indicate several possible endogenous and exogenous explanations for the genetic diversity difference between the sample sites. The thesis study suggested that a physiological adaptation response, population genetic dynamics (i.e., genetic drift and a in bottleneck), and food web cycle alterations played a key role in Glyptotendipes genetic diversity levels in response to varying levels of environmental stressors. The thesis study demonstrated that chironomid hemoglobin protein evaluated by the SDS-PAGE biomarker has potential for both identification purposes and to determine genetic diversity of the species which may be applied to bioassessment of wetland environmental health.

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