, 2005, Lammel et al., 2007, Tamamura et al., 2007, Hung et al., 2009b and Chen et al., 2010), but it is difficult to quantitatively evaluate the flux of PAHs. The observed results suggest that petroleum supply is likely an important PAH source in the study area. The second key source is a mixed source of petroleum and combustion of grass/wood/coal. This is supported by previous investigations that reported that combustion and terrestrial discharge are the two major sources of sedimentary PAHs in the ECS (Feng et al., 2007 and Hung et al., 2011). Frontal zones are important

nursery, feeding, and fishing grounds (Nakata Epigenetic inhibitor solubility dmso et al., 2000 and Kasai et al., 2002, and references in Belkin et al., 2009). According to Landrum et

al. (1992), PAHs can be taken up by marine organisms through direct adsorption of freely dissolved chemicals and/or direct contact and ingestion of sediment particles. We could not distinguish the exact mechanism, which resulted in elevated PAHs concentrations in zooplankton in our study area, but the distribution patterns of Chl-a concentrations and zooplankton abundance in the ECS along the three transects were similar to those of PAHs ( Fig. 3A–C). The results thus strongly suggest that zooplankton accumulate PAHs via food chain magnification and/or absorption of PAHs. Because most of PAHs are hydrophobic, they can be easily incorporated Afatinib manufacturer by phytoplankton ( Bruner et al., 1994 and Vigano et al., 2007). Ko et al. (2012) reported that many organic pollutants (including PCBs and organo-chlorine pesticides) can be absorbed quickly in phytoplankton culture experiments. In other words, PAHs in/on phytoplankton can be taken up by zooplankton and accumulated in zooplankton. These higher levels of

PAHs in zooplankton may be transported to higher eutrophic levels of marine organisms through the marine food web because the coastal hydrographic frontal zones are important fish nursery grounds. Additionally, the fecal pellets produced by PAH-contaminated zooplankton may carry PAHs to greater depths. Recently, Tanabe et al. (2005) reported Rucaparib chemical structure that deep-sea organisms in the ECS contained organo-chlorine pollutants and suggested that organic pollutants in deep-sea organisms may be from coastal regions via horizontal transport. We did not measure the content of PAHs in fecal pellets generated by zooplankton, but Wang et al. (2001) reported that the fecal pellets produced by Capitella in sediments appear to contain more PAHs than organic matter associated with clay minerals. Additionally, Prahl and Carpenter (1979) suggested that the zooplankton fecal pellets, collected in Dabob Bay [a bay adjacent to Puget Sound in Washington, USA] may control PAH removal to sediments. Furthermore, Cailleaud et al.