Dear Colleagues, We are pleased to announce publication of the following article: Peterson SP, Peterson MG, Debier C, Covaci A, Dirtu A, Malarvannan G, Crocker DE, Schwarz LK, Costa DP (2015) Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants. Science of the Total Environment 533:144-155. DOI: 10.1016/j.scitotenv.2015.06.097 *Highlights: * All elephant seals had detectable concentrations of DDTs, PCBs, CHLs, and PBDEs. • We quantified changes in the blubber burdens of POPs, within individual seals. • Despite mass dilution while foraging, blubber burdens showed POP ingestion. • Bioaccumulation of some POP compounds in seals varied across the North Pacific. • Ratio of ΣDDTs:ΣPCBs corroborated latitudinal variation seen in other species. *Abstract:* As top predators in the northeast Pacific Ocean, northern elephant seals (*Mirounga angustirostris*) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N=24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males,we sampled different adults and sub-adults before (N=14) and after (N=15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ΣDDTs and ΣPCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ΣDDT and ΣPBDEs were highly correlated in blubber and serum. While ΣPCBs were highly correlated with ΣDDTs and ΣPBDEs in blubber and serum for males, ΣPCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ΣDDTs, ΣPBDEs, MeO-BDE 47, as well as the ratio of ΣDDTs to ΣPCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations ofΣDDTs and ΣPBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in 13C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in deep ocean food webs. Please contact me if you do not have access to this article and you would like a pdf (sarahpeterson23@gmail.com). Best regards, Sarah -- Sarah Peterson, PhD Ecology and Evolutionary Biology Department University of California Santa Cruz - Long Marine Lab 100 Shaffer Road Santa Cruz, CA 95060