Great Pacific Garbage Patch

Great Pacific Garbage Patch. It is a vast area of the North Pacific Ocean characterized by a high concentration of marine debris, primarily plastics. The patch is not a solid mass but a diffuse region within the North Pacific Gyre, where converging currents trap floating litter. Its existence highlights a significant global issue of ocean pollution.

Description and composition

The patch is located within the North Pacific Subtropical Gyre, bounded by the North Pacific Current, the California Current, the North Equatorial Current, and the Kuroshio Current. Surveys by organizations like The Ocean Cleanup and Scripps Institution of Oceanography have shown the debris field is largely composed of microplastics, fragments less than five millimeters in size, intermixed with larger items like discarded fishing gear and consumer products. The composition includes polyethylene and polypropylene, common in packaging and ghost nets. The total mass is estimated to be tens of thousands of metric tons, with the area's size often compared to Texas or France.

Formation and causes

The patch forms due to the action of the North Pacific Gyre, a system of rotating ocean currents that acts as a convergence zone. Wind-driven surface currents, part of the larger Coriolis effect, transport debris from coastal regions across the Pacific Rim, including Asia and North America, into the gyre's calm center. Primary sources include riverine outflow from systems like the Yangtze River, accidental loss from commercial fishing and shipping lanes, and improper waste management on land. The National Oceanic and Atmospheric Administration notes that plastics persist because they photodegrade slowly under ultraviolet radiation, breaking into smaller pieces rather than biodegrading.

Environmental impact

The debris poses severe threats to marine life across the North Pacific. Animals such as Laysan albatross and loggerhead sea turtle ingest plastic, leading to internal injuries, starvation, and death. Entanglement in derelict nets, a process documented by the Marine Mammal Center, affects species including humpback whale and Hawaiian monk seal. Furthermore, plastics absorb pollutants like polychlorinated biphenyl and DDT, which can enter the food web and potentially impact human health through consumption of Pacific salmon or tuna. The United Nations Environment Programme has identified such pollution as a critical threat to biodiversity.

Mitigation and cleanup efforts

Cleanup initiatives range from technological projects to policy-driven prevention. The most prominent effort is led by The Ocean Cleanup, a Netherlands-based nonprofit founded by Boyan Slat, which deploys systems to concentrate and remove plastic. International agreements also play a role, such as the International Convention for the Prevention of Pollution from Ships and the UNESCO-backed Global Partnership on Marine Litter. Non-governmental organizations like the Ocean Conservancy organize large-scale International Coastal Cleanup events to intercept waste before it reaches the ocean. The European Union has implemented directives targeting single-use plastics.

Research and monitoring

Ongoing scientific study is crucial for understanding the patch's dynamics. Research voyages, such as those conducted by the Scripps Institution of Oceanography and the Sea Education Association, use neuston net to sample surface plastics. Remote sensing via NASA satellites and aerial surveys by projects like The Ocean Cleanup help map distribution. Key research institutions include the Woods Hole Oceanographic Institution and the Algalita Marine Research and Education foundation, founded by Charles Moore, who brought widespread attention to the patch. Data is often shared through the Global Ocean Observing System.