Microplastic pollution in deep-sea sediments
We have all heard the phrase: "We know more about the surface of the moon than the deep sea". Unfortunately, this is not exaggeration: the deep sea is the largest ecosystem on Earth, but also one of the least studied despite it harbouring a high biodiversity and a wealth of resources. Sadly, the deep seafloor is still, for most people, out of sight and therefore out of mind. This has encouraged the dumping of waste of all sorts into deep waters. For centuries, this was organic, degradable matter. Now, our solid wastes often contain synthetic elements, plastics in particular. In recent years, more and more reports have been published that demonstrate the large presence of plastic litter in the deep sea: the seafloor of the Mediterranean, Atlantic canyons and even Arctic waters are covered with plastic litter. Recently, our lab added another pollutant to the list: for the first time ever, microplastics were recorded in deep-sea sediments originating from several location worldwide. These results show that microplastics have penetrated the marine environment to a larger extent than previously assumed.
Microplastics are small plastic particles (<1 mm) originating from the degradation of larger plastic debris. These microplastics have been accumulating in the marine environment for decades and have been detected throughout the water column and in sublittoral and beach sediments worldwide. However, up to now, it has never been established whether microplastic presence in sediments is limited to accumulation hot spots such as the continental shelf, or whether they are also present in deep-sea sediments. Here we show, for the first time ever, that microplastics have indeed reached the most remote of marine environments: the deep sea. We found plastic particles sized in the micrometre range in deep-sea sediments collected at four locations representing different deep-sea habitats ranging in depth from 1100 to 5000 m. Our results demonstrate that microplastic pollution has spread throughout the world's seas and oceans, into the remote and largely unknown deep sea.
Van Cauwenberghe L, Vanreusel A, Mees J, Janssen CR. 2013. Microplastic pollution in deep-seea sediments. Environmental Pollution. In press. DOI: 10.1016/j.envpol.2013.08.013