In remote Antarctica, Colombian marine biologist Paulo Tigreros dips a net into the icy waters in his hunt for microplastics in what should be one of the best-preserved ecosystems in the world. Like a sieve, the net lets water pass through as it retains the small solid particles that float in the Gerlache Strait, a natural corridor approximately 160 kilometers (99 mile) long separating the Palmer Archipelago and the end of the Antarctic Peninsula.