Pollution in the South Pacific Ocean affects Rapa Nui
by Raquelle de Vine
& Charles Moore
A water bottle lost down the drain in Sydney or a fishing buoy lost overboard in Peruvian waters can find its way into this central accumulation area, or the shores of Rapa Nui – most likely photodegraded, weathered and /or overgrown by marine organisms but all the same it is there, because plastic biodegrades over time scales of decades or longer. This central convergence of marine plastic debris is what has attracted Algalita for their 2016/2017 Expedition. Since 1999, two years after sailing through part of the North Pacific Subtropical Gyre, now commonly referred to as “Great Pacific Garbage Patch,” Captain Moore and the ORV Alguita have returned there ten times. Each time they have been monitoring the plastic pollution within it. This 2016/17 voyage is to begin monitoring and comparison with the South Pacific Gyre.
By the time the expedition arrived in Rapa Nui we had conducted 40 trawls, however this was only the beginning. We took refuge at Rapa Nui for the holiday period and to prepare for the crossing to Mainland Chile, via the gyre, we also conducted a week-long sampling in the offshore waters. During our time we enjoyed great hospitality and kinship from the locals, particularly Christian Rapu and Sebastian Yankovic-Pakarati.
Upon arriving in the surrounding waters of Rapa Nui, we experienced greater and greater quantities of plastic litter and densities which didn’t start to decrease until we were much further East, near the Island of Robinson Crusoe. Both within the waters around Rapa Nui and crossing the South Pacific Gyre, our trawl samples were coming in thick with plastic micro fragments, filament and fishing line – the South Pacific’s very own Plastic Soup. Captain Moore’s subjective feeling of the extent of accumulation of the microplastic debris likens it to the samples they were taking in 2007 in the North Pacific gyre. This was unexpected to him, as in 2011 when Algalita collaborated on an initial study of microplastics in the South Pacific Subtropical Gyre, the total quantity of microplastics gathered in samples could be held in a single hand…. This is no longer the case.
The comparison of larger litter to the North Pacific Gyre has also been interesting as the majority of identifiable objects found in the North Pacific Gyre are consumer goods, whereas during our current collection only 22.5 % has been consumer goods, 52% has been related to industrial fisheries, and the rest was unidentifiable. Most items were buoys, lines, ropes, buckets, fuel/oil containers and fish bins. We even hauled in a lone ghost net drifting along and discovered a disused FAD, Fish Aggregation Device. This is an artificial object which is used to attract deep sea fish, such as marlin, tuna and mahi-mahi (dolphin fish). Generally they are found on buoys or floaters that are attached to the ocean floor by blocks of cement. The fish are fascinated by any floating object, so these can be used to mark their breeding grounds. More than 300 species of fish will gather around the FAD, which are used both for recreational and commercial fishing. Alguita, together with organizations in Rapa Nui, is demanding that the nations of the world take effective measures to reduce the contamination in the oceans and to protect the still pristine ecosystems, such as the waters around Rapa Nui.
In the sand of Rapa Nui there are animals so small that they can hardly be seen with the bare eye. You need a microscope to see them. These animals live in the small spaces between sand grains.
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