Event Title

Embryonic exposure to persistent organic pollutants and mercury in marine birds and investigations into associated hepatic gene expression alterations

Streaming Media

Presentation Abstract

Marine birds can bioaccumulate considerable persistent contaminant body burdens, and maternal transfer to eggs may expose sensitive embryos to high concentrations. Yet, deleterious effects inferred from tissue residue concentrations suffer from uncertainty, and high-throughput techniques to assess biological effects caused by persistent bioaccumulative contaminants or potential environmental disasters like oil spills are lacking in wildlife sentinel species. Our research focuses on two wildlife sentinel species, the rhinoceros auklet (Cerorhinca monocerata) and the double-crested cormorant (Phalacrocorax auritus), which occupy an offshore-nearshore habitat gradient, and aims to demonstrate the utility of hepatic gene expression for linking embryonic contaminant burdens to transcript-level effects in vivo. To quantify embryonic body burdens, we measured the concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), brominated and chlorinated flame retardants (FRs), and total mercury (THg) in developed (pre-hatch to pipping) sentinel species embryos from breeding colonies in the northeast Pacific Ocean from 2017-2019. Some THg observations in C. monocerata (0.3-0.6 µg g-1 ww) fall within literature values for embryotoxicity in this order of seabirds (LC50 0.3-4.3 µg g-1 ww), and contaminant burdens are considerably higher in P. auritus embryos from Vancouver harbour than C. monocerata from offshore colonies. We are currently profiling hepatic gene expression in the sampled embryos with ToxChip qPCR arrays to determine whether contaminant exposure is associated with dysregulation of genes involved in pathways including xenobiotic metabolism/biotransformation, oxidative stress, thyroid hormone function, lipid metabolism, and many others. Together, these data will signal whether an embryotoxicity hazard from THg and other persistent halogenated contaminants to marine birds in and around the Salish Sea exists, if any spatial patterns exist, and if these correlate to liver gene expression profiles.

Session Title

Track: Contaminants, Plastics, Microplastics, Toxicology & Stormwater – Posters

Conference Track

Contaminants, Plastics, Microplastics, Toxicology & Stormwater

Conference Name

Salish Sea Ecosystem Conference (2020 : Online)

Document Type

Event

SSEC Identifier

2020_abstractID_4077

Start Date

21-4-2020 9:00 AM

End Date

22-4-2020 4:45 PM

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Language

English

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Apr 21st, 9:00 AM Apr 22nd, 4:45 PM

Embryonic exposure to persistent organic pollutants and mercury in marine birds and investigations into associated hepatic gene expression alterations

Marine birds can bioaccumulate considerable persistent contaminant body burdens, and maternal transfer to eggs may expose sensitive embryos to high concentrations. Yet, deleterious effects inferred from tissue residue concentrations suffer from uncertainty, and high-throughput techniques to assess biological effects caused by persistent bioaccumulative contaminants or potential environmental disasters like oil spills are lacking in wildlife sentinel species. Our research focuses on two wildlife sentinel species, the rhinoceros auklet (Cerorhinca monocerata) and the double-crested cormorant (Phalacrocorax auritus), which occupy an offshore-nearshore habitat gradient, and aims to demonstrate the utility of hepatic gene expression for linking embryonic contaminant burdens to transcript-level effects in vivo. To quantify embryonic body burdens, we measured the concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), brominated and chlorinated flame retardants (FRs), and total mercury (THg) in developed (pre-hatch to pipping) sentinel species embryos from breeding colonies in the northeast Pacific Ocean from 2017-2019. Some THg observations in C. monocerata (0.3-0.6 µg g-1 ww) fall within literature values for embryotoxicity in this order of seabirds (LC50 0.3-4.3 µg g-1 ww), and contaminant burdens are considerably higher in P. auritus embryos from Vancouver harbour than C. monocerata from offshore colonies. We are currently profiling hepatic gene expression in the sampled embryos with ToxChip qPCR arrays to determine whether contaminant exposure is associated with dysregulation of genes involved in pathways including xenobiotic metabolism/biotransformation, oxidative stress, thyroid hormone function, lipid metabolism, and many others. Together, these data will signal whether an embryotoxicity hazard from THg and other persistent halogenated contaminants to marine birds in and around the Salish Sea exists, if any spatial patterns exist, and if these correlate to liver gene expression profiles.