Halogenated1'-methyl-1,2'-bipyrroles (MBPs) in the Northwestern Atlantic

Kristen Pangallo, Ph.D., 2009
Christopher Reddy, Advisor

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 characteristics with persistent organic pollutants (POPs), and may be useful natural analogues for these anthropogenic compounds. Further, their unique structure suggests that their producer(s) may have new genes to add to current knowledge of biosynthetic chemistry. The objectives of this dissertation were to clarify the environmental distribution of MBPs, to examine whether MBPs biomagnify, and to investigate possible origins of these compounds. 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. 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 signature of biosynthesis may assist in elucidating the organism(s) and mechanism(s) responsible for MBP production.