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Research Theme: Marine Debris

The mid-20th century saw the mass introduction of new materials that resist oxidative and bacteriological decay. These new materials, mostly plastics, have resulted in a build-up of debris over time, with negative aesthetic and ecological consequences. In addition to larger plastic items that make their way into the marine environment, smaller pieces (<5mm) are of growing concern. These smaller items are typically a result of larger items being broken down over time and loss of pre-production plastic pellets (raw materials for producing larger plastic items) during transport. These pellets are considered a danger to marine life due to ingestion, and may represent a pathway for persistent organic pollutants to enter the food chain.

SCCWRP Research

Southern California beaches and marine waters are used extensively for a variety of recreational purposes, attracting an estimated 150 million visitors annually. Consequently, most debris studies in Southern California have focused on the composition and abundance of debris on beaches. On the other hand, SCCWRP has participated in studies that not only looking at debris on beaches, but also in other habitats or receptacles: the seafloor, nearshore surface water, and water-column water.

Pre-production plastic pellets; debris that has washed onshore; floating-debris patterns in the North Pacific Gyre.

Marine debris research areas include:

  • Debris on Beaches

    Most studies of beach debris are conducted as part of beach cleanup efforts. In the late nineties, SCCWRP performed a pioneering study to more comprehensively quantify and characterize marine debris on southern California beaches. More recent follow-up studies were initiated in 2009 so as to inform management and regulatory approaches for addressing the sources of beach debris. These may include both point and nonpoint sources of debris like preproduction plastic pellets. SCCWRP and other collaborators work to understand and describe trends for not only larger trash, but for these smaller plastics as well. Though unseen, they may present a larger ecological problem; their shape and color often mimic food and may be consumed by wildlife.


  • Plastic Debris Offshore

    SCCWRP and other collaborators have been working to understand and describe trends for not only larger trash but smaller debris as well. Most studies of marine debris have focused on large debris in highly populated areas because of aesthetic values. Hence, most people think of marine trash as the large items on the beach or in the water near recreational areas. However, large items discarded into the environment often break into smaller pieces through mechanical and ultraviolet degradation processes. In addition, other smaller plastic particles, which mostly consist of pre-production plastic pellets (a common starter material for larger plastics), are lost to the environment through accidental spills during transportation. Though unseen, these smaller plastics may present a larger ecological problem. Often, their shape and color mimic food. Birds and fish eat them because they resemble planktonic organisms, and filter feeders vacuum up the smaller sizes.


  • Plastic Debris on the Ocean Bottom

    Large-scale surveys of the Southern California Bight (SCB) are typically coordinated by SCCWRP every five years. The first study in 1994 provided a baseline. In 1994 about 14% of the SCB had anthropogenic debris, whereas in 1998 this number increased to 23%, followed by 25% in 2003 and 21% in 2008. This increase is largely due to the fact that more extensive surveys were done after 1994 (e.g., 143 stations in 2003, 314 stations in 1998, and 210 stations in 2003, compared to 114 stations for 1994) as well as the inclusion of bays, harbors, and islands. The SCB Regional Monitoring Program Reports describe debris found in trawls (under "Assessment Reports," "Demersal Fishes and Megabenthic Invertebrates").

For more information on Marine Debris, contact Shelly Moore at shellym@sccwrp.org (714) 755-3207.
This page was last updated on: 3/26/2014