Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) in the northwestern Atlantic
Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) in the northwestern Atlantic
Date
2009-09
Authors
Pangallo, Kristin C.
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Location
Northwestern Atlantic
DOI
10.1575/1912/3143
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Keywords
Chemical oceanography
Environmental impact analysis
Environmental impact analysis
Abstract
Halogenated 1’-methyl-1,2’-bipyrroles (MBPs) are a distinctive class of
marine organic compounds. They are naturally produced, they have a unique
carbon structure, they are highly halogenated, and they bioaccumulate in upper
trophic levels. MBPs share many characteristics with persistent organic
pollutants (POPs), and may prove to be useful natural analogues for these
anthropogenic compounds. Further, their unique structure suggests that their
biosynthetic organism(s) may have new genes to add to current knowledge of
biosynthetic chemistry. The objectives of this dissertation were to further clarify
the environmental distribution of MBPs, to examine whether MBPs biomagnify,
and to investigate possible origins of these compounds through their stable
nitrogen isotopic signatures.
Results from these investigations have shown that over 40 highly
brominated MBP congeners are present in marine mammals, fish, and squid
from the Northwestern Atlantic Ocean. The most abundant MBPs do appear to
biomagnify through the food web to reach the concentrations observed in marine
mammals. This additional evidence affords greater confidence in the use of
MBPs as natural analogues for POPs. However, differences in the environmental
chemistry of MBPs and anthropogenic compounds are also evident, and may be
due to these compounds’ different origins, or to the capacity of degradative
enzymes to act upon them. Finally, compound-specific nitrogen isotope analyses
on MBPs isolated from dolphin blubber show that these compounds are
dramatically enriched in 15N relative to other biosynthetic organic compounds.
This enrichment is likely a signal imparted during biosynthesis, and may assist
in elucidating the organism(s) and mechanism(s) responsible for the biosynthesis
of MBPs.
Description
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2009
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Citation
Pangallo, K. C. (2009). Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) in the northwestern Atlantic [Doctoral thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution]. Woods Hole Open Access Server. https://doi.org/10.1575/1912/3143