Fig. 4: Weight-loss biodegradation rate of plastics in various deep-sea areas and the degradation process for plastic films.

a The weight-loss biodegradation rate of injection-molded plastic samples placed in various ocean environments (2-6 m depth, off the port of JAMSTEC Yokosuka Headquarters; 855 m depth, off a bathyal hydrocarbon seepage near Hatsushima Island; and 5552 m depth, off an abyssal plain around Minamitorishima Island) for ~1 year. Values are given from n = 1 results (Supplementary Data 3). See Table 1 and Table 2 for abbreviations regarding installation location and samples. b The weight-loss biodegradation rates of various melt-pressed PHA and biodegradable polyester films when placed on the shore or at various deep-sea sites. Values are given as average of n = 4 independent samples with its standard deviation (Supplementary Data 1). c Plot of the biodegradation rate of each plastic against depth, showing that the rate slows with depth. The represented data is the average of n = 2 or n = 4 independent samples. d The estimated period for biodegradation of a typical plastic bag (size: 18 cm × 42 cm, thickness: 15 μm, weight: 3 g) based on the results of this study if it is replaced by the above PHA. e The weight-loss of polysaccharide ester derivatives placed in various ocean environments (2-6 m at PJM, 855 m at BHT, 5552 m at AMN) for ~1 year. Values are given from n = 1 results (Supplementary Data 3). Source data are provided as a Source Data file.