Zooplankton fecal pellets as a vector transporting microplastics and associated toxins to the deep ocean

Abstract

Toxins within the fecal pellets of zooplankton were measured along a transect from Hawaii to San Diego, passing through the southern edge of the Great Pacific Garbage Patch. Zooplankton were collected via a vertical net tow at 4 different stations. Fecal pellets were analyzed in the lab using gas chromatography – time of flight mass spectrometry. At three of the four stations, the fecal pellets contained anthropogenic compounds- mainly phthalic acid. Station 6 (25.6595, -149.5) possessed the highest concentrations of phthalic acid at around 0.87 g/m3, yet this station was not within the Great Pacific Garbage Patch. Fatty acids such as Hexadecenoic acid were also common within the samples collected. The prevalence of plasticizers and the locations at which they were found in this study can question current assumptions about the exact size and location of the Great Pacific Garbage Patch and suggest it is larger than previously known. The data in this study also suggests that more research should be done to assess how chemicals like phthalic acid can alter the settling rate of zooplankton fecal matter and what implications this can have on the ocean’s biological pump.