06.06.2012 - Rio+20

Toxic tides

Land-based sources (such as agricultural run-off, discharge of nutrients and pesticides and untreated sewage including plastics) account for approximately 80% of marine pollution, globally. Marine habitats worldwide are contaminated with man-made debris.

Litter can accumulate in huge floating garbage patches or wash up on the coasts. Light, resistant plastics float in the Ocean, releasing contaminants as they break down into toxic micro-particles that animals mistake for food.

Who is affected and why does it matter?

Excessive nutrients from sewage outfalls and agricultural runoff have contributed to the number of low oxygen (hypoxic) areas known as dead zones, where most marine life cannot survive, resulting in the collapse of some ecosystems.

  • There are now close to 500 dead zones covering more than 245,000 km² globally, equivalent to the surface of the United Kingdom.
  • The United Nations Environment Programme estimated in 2006 that every square mile of ocean contains 46,000 pieces of floating plastic. Micro-plastics and plastic pellets are found on most beaches around the world

What is UNESCO doing?

The UNESCO-IOC Nutrients and Coastal Impacts Research Programme focuses on interactions between climate, nutrients, and coastal dynamics, and the challenges and opportunities that resulting ecosystem changes pose for tourism, institutions and governance. Through this activity, IOC is an active partner in the Global Partnership for Nutrient Management, which strives to deliver better tools for management of nutrient loading to the marine environment.

The Harmful Algal Bloom Programme fosters effective management of, and scientific research on, harmful algal blooms to understand their causes, predict their occurrences, and mitigate their effects.

UNESCO-IOC is a sponsor of the joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP), the United Nations mechanism for collaboration and coordination which conducts assessments and in-depth studies to evaluate the state of the marine environment, including socio-economic aspects, and identify emerging issues.

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