Figure 1.
Location of the 57 net stations sampled during this study.
Dot colors indicate the voyage when the net station was sampled and numbers follow the chronological order of sampling. Pictures of the two types of net used are shown in the right panel.
Figure 2.
Size and types of marine plastics collected around Australia.
Bars indicate the number of plastic pieces within each size category (<2.5, 2.5 – 4.9, 5 – 10, >10 mm) and colors show the amount of each plastic type within size categories. Examples of the types of plastic we collected are shown in the photos, including our biggest fragment of hard plastic (length = 57 mm, net station 32), soft plastic (length = 73 mm, net station 57, note the Indonesian words), and expanded polystyrene (Styrofoam cup fragment, length = 24.3 mm, net station 28).
Figure 3.
Mean infrared spectra of the plastic pieces within each polymer type.
Figure 4.
Mean sea surface plastic concentration (Cs) at the 57 net stations.
White crosses indicate location of major Australian cities (population >1 million). From west to east: Perth, Adelaide, Melbourne, Sydney, and Brisbane.
Figure 5.
Sea surface plastic concentration (Cs) versus a) wind speed (U10) and b) water friction velocity (u*w).
In (b) we also show the linear fit (Cs = a (u*w)b) and theoretical model estimates for Cs, when depth-integrated plastic concentration (Ci) is equal to 8966 (mean Ci of the 171 net tows) and significant wave height (Hs) is equal to the mean (1.85 m), maximum (4.78 m) and minimum (0.47 m) values estimated for the 57 net stations.
Figure 6.
Mean and standard error of sea surface (Cs) and depth-integrated (Ci) plastic concentrations.
Blue represents mean and standard error of Cs and red represents mean and standard error of Ci.
Figure 7.
Mean depth-integrated plastic concentration (Ci) at the 57 net stations.
White crosses indicate location of major Australian cities (population >1 million). From west to east: Perth, Adelaide, Melbourne, Sydney, and Brisbane.
Figure 8.
Cumulative probability distribution of virtual particles arriving at the 57 net stations.
The month when the virtual particles (25 per day) were released is indicated in each panel. Backtracking dispersal time was equal to 45 days and arriving destinations (net stations) are marked with purple dots. See also Maps S1.
Figure 9.
Real drifter pathways arriving at the 57 net stations.
Purple dots indicate net station locations and asterisks indicate drifter release areas. See also Maps S2.