Scales of Spatial Heterogeneity of Plastic Marine Debris in the Northeast Pacific Ocean
A) Dry mass of microplastic; B) Dry biomass zooplankton; C) Ratio of plastic dry mass to zooplankton dry mass. Dry masses are given in mg m−2. Boxes are middle 50% of the data, with the line denoting the median. Whiskers indicate 5th and 95th percentiles of the data, and hollow circles indicate maximum and minimum values. Abbreviations are North Pacific Subtropical Gyre (NPSG), transition region (TR), and California Current (CC), but water masses should be considered highly approximate. Time of day is abbreviated to D = day, C = crepuscular, and N = night. Only data from Summer 2009 are shown. Sample sizes are as follows: NPSG-D = 48, NPSG-C = 12, NPSG-N = 30, TR-D = 9, TR-N = 6, CC-D = 5, CC-C = 3, CC-N = 6.