Plastic Debris Rivers to Sea Project: Minimizing Land-Based Debris Polluting Oceans

Plastic Debris Rivers To Sea Project minimizing trash in oceans from outside sources Land-based discharges of debris comprise largest source of marine debris in oceans. The Plastic Debris, Rivers to Sea Project seeks to minimize the land-based discharges of marine debris. Just like ocean-based marine debris, land-based discharges of human-made debris are comprised mostly of plastics.

The threat and impacts of marine debris have long been ignored.  Perhaps it is the perceived vastness of ocean and lack of visibility of marine debris to most people that has allowed society to dismiss the problem as a serious threat. However, recent research demonstrates that Ballona Creek empties rain runoff trash into Pacific Ocean just south of Santa Monica, California into the Pacific Ocean. After rainfall the beaches are closed for at least three days to swimmers. quantities and impacts of marine debris are significant and increasing. The Algalita Marine Research Foundation’s investigation of plastic in the North Pacific Central Gyre of the Pacific Ocean showed that the mass of plastic pieces was six times greater than zooplankton floating on the water’s surface. This study is one of many that demonstrate that our oceans have become the virtual garbage can for the developed and developing world

Most of the marine debris in the world is comprised of plastic materials. The average proportion varies between 60 to 80% of total marine debris.(2) In many regions, plastic materials constitute as much as 90 to 95% of the total amount of marine debris.(3)

plastic-pollution-2Nearly 80% of marine debris comes from land-based sources.(4) Most of the land-based debris is conveyed to oceans via urban runoff through storm drains. The main sources of plastic and other types of anthropogenic (human-made) debris in urban runoff include: litter (mostly bags, packaging and single-use disposable products), industrial discharges, garbage transportation, landfills, construction debris, and debris from commercial establishments and public venues.

In November 2003, the Algalita Marine Research Foundation (AMRF) received a grant from the California State Water Resources Control Board (SWRCB) to implement a project designed to assess and begin to reduce sources of plastic debris and other discarded materials in urban runoff. This project, titled Plastic Debris, Rivers to Sea, is being implemented with the help of the California Coastal Commission.


Imagine a world where the oceans are free of plastic trash. Algalita envisions a marine environment that is healthy, sustainable and productive for all living creatures, free from plastic pollution.  We believe that together, we can combat the crisis through research, education, and action. Do you share our vision?

Marine Research & Education, Solutions to Plastic Pollution
and How much plastic is there in the oceans?” Bill Francis

Accumulation of Plastic in the Marine Environments

Picture of plastic pollution in the oceans, a major problem for ocean health. About 8 million tons of plastic enters the ocean each year (Jambeck et al., 2015).  5.25 trillion pieces of plastic weighing 269,000 tons can be found floating in the global ocean. Most of the 5.25 trillion pieces of plastic are small, between just 1mm and 4.75mm in size (Eriksen et al., 2014).  The accumulation of plastic in the ocean often concentrates around gyres, which are specific regions where oceanic currents converge (Maximenko et al., 2012).

These gyres have been documented in many regions of the world’s oceans and have become a focus of numerous marine studies to document the accumulation of floating plastic debris (NOAA, 2012).

  • North Pacific Subtropical Gyre (commonly called the Great Pacific Garbage Patch). Plastic debris that transports to this gyre accumulates and is likely to remain there. The true size and mass of the trash in the gyre is unknown, given that less research has been done here than in many of the others (NOAA, 2013).  In this gyre, there is on average six times more plastic than zooplankton by dry weight.  This ration indicates a high availability of harmful, unsuitable food items to potential consumers (Moore et al., 2001).
  • South Pacific Subtropical Gyre. Microplastic pollution up to 26,898 particles per km −2 has been documented in the South Pacific subtropical gyre (Eriksen et al. 2013).
  • North Atlantic Subtropical Gyre. The synthesis of 22 years of surveys to assess the density of plastic debris accumulating in this gyre yielded a maximum density of 580,000 pieces per square kilometer (Law et al., 2010). It has been estimated that 88% of plastic material found in this gyre was smaller than 10 mm long (nearly half the size of what was found in the 1990s), implying progressive degradation of plastic in the marine environment (Moret-Furgeson et al., 2010).
  • South Atlantic Gyre. Studies have yielded findings of between 1,300 to 3,600 plastic pellets per square kilometer (Morris, 1980; Barnes et al., 2005).
  • Indian Ocean, the Bay of Bengal, and the Straits of Malacca. Studies have revealed 18,000 counts of debris, with 98% of them being plastic, in over 3,275 km of transects (Ryan, 2013).
  • Western North Atlantic. A recent study showed a stabilizing concentration of plastic debris (Law et al., 2010). One speculation is that the rate of plastic entering oceanic gyres is now being matched by the rate that plastic is sinking from the surface, given that as plastic remains in the ocean and breaks down, it becomes more dense and thus more apt to diffuse throughout the water column.

Bren School of Environmental Science & Management UC Santa Barbara
Authors: Jessica Midbust, Michael Mori, Paula Richter, Bill Vosti
Advisor: Derek Booth

Collecting trash in Los Angeles River which empties chemicals and trash into Pacific Ocean Conducted in 2013, this intensive nine-month research project was the first to focus on identifying the major sources of terrestrial plastic debris in a highly urbanized region. Graduate student researchers from the Bren School analyzed the sources and movement of plastic debris in two major Southern California watersheds. In this 256-page report, authors present their quantitative analyses along with a comprehensive report that includes a conceptual model, policy analysis and policy recommendations. Recommended action items include statewide legislation, improvement of local regulatory mechanisms, increased monitoring of production facilities and more.

Project Brief
Project Synopsis
Full Report

Ocean Pollution Prevention Research Research: As the pioneers in the study of plastic pollution, we were the first to spearhead the research methodology for collecting and analyzing microplastic samples from the ocean. 
Debris Sampling Off-AlguitaExpeditions: Captain Moore and his research team continue to monitor one of the most polluted areas of the world – the North Pacific Gyre, home of the swirling vortex of plastic trash known as the Great Pacific Garbage Patch.
Education is key to cleaning up oceans and our world. Education: Algalita bridges real-world science with real-time solutions to inspire teachers and students to find their place within the movement to combat plastic pollution in their own schools and communities.
Youth Summit 2016 Ocean Institute 2016 POPS Youth Summit: Join us at the Ocean Institute in Dana Point, CA Spring 2016 for the 4th annual POPS International Youth Summit – where students from around the world come together to fight for a clean ocean!