Fishing for scrap metal
Fishing for scrap metal
The oceans are the ultimate sink for all pollution, 70-80 per cent of which originates from land-based sources. Globally, some 450 cubic kilometers of wastewater - from untreated or partially treated sewage, industrial effluents and agricultural runoff - are carried into coastal waters by rivers and streams every year. Nearly everywhere in the developing world coastal cities dump their untreated wastes into the sea. No place in the world's seas is immune from pollution, as ocean currents transport pollutants to the far corners of the world.
Pollutants in our seas have affected the populations of many marine species. A few examples include declines in the population of some European harbour seal populations due to PCBs; cancer and various chronic diseases in St. Lawrence beluga whales from a wide variety of contaminants; decline in Alaskan spectacled eiders (a sea duck) from lead poisoning; malformation, chromosome abnormalities and mortality of fish eggs and larvae in the mid-west Atlantic; increased numbers of mortalities in disease-related marine mammal die-offs, including Mediterranean striped dolphins and US coastal bottlenose dolphins.
Meanwhile, oil spills continue to kill many thousands of sea birds. One study estimated that more than 42,000 Magellanic penguins alone die from oil pollution annually along the Argentinean coast.
One of the most pressing threats to the oceans is over-enrichment by nutrients, primarily nitrogen, from the run-off of agricultural fertilisers, emissions from fossil fuel combustion, various land-use changes, and from the discharge of human and animal wastes. Many estuaries now receive over a thousand times more nutrients per unit surface area than heavily fertilised agricultural fields thus making them the most heavily fertilised ecosystems on the planet.
Excess nutrients and changes in nutrient balances have led to the growing eutrophication of numerous coastal waters worldwide including, for example, Chesapake Bay, the northern Adriatic Sea, the North and Baltic Seas, and the Black Sea. The partial or complete removal of dissolved oxygen from the water column (anoxia/hypoxia), a consequence of eutrophication, has had a wide-ranging effect, including the mass mortality of benthic organisms, die-backs in seagrass meadows, and declines in biodiversity, and is considered to be an important factor in the long-term decline of many coastal fisheries and to overall changes in the structure and function of estuarine and coastal environments.
Any increase in harmful blooms or toxicity events obviously increases the potential for their often disastrous effects including human illness and death, spectacular fish kills, closed shellfish beds, and severe economic loss.
The Convention on the Law of the Sea adopted in 1994 has begun the job of protecting the world's oceans but there is a long way still to go. The Convention has established a general framework requesting States to adopt laws, regulations and standards to prevent, reduce and control pollution from all possible sources: from land-based, sea-bed activities, dumping, vessels sources and the atmosphere.
It is now up to responsible States to translate these general injunctions into detailed rules. In some cases, the adoption of Conventions such as that on Climate Change or on Biological Diversity will have a positive impact. Similarly the Plan of Action concerning land-based sources of pollution is promising, as almost 80 per cent of the pollution of the sea stems from land sources.
However, more than conventions and plans of action are needed. The future of the ocean needs a greater understanding of its importance for human survival.
The cartoonist: Ubiratan Nazareno Borges Porto, or Biratan, was born in Belém, Pará state in the heart of Amazonian Brazil, in 1950. He is a professional cartoonist and a mandolin player in his spare time. He has five humour books published in the US, Italy, Belgium and Holland. In 2002, he won first place in the International Cartoon Festival of Knokke-Heist in Belgium. He has also created animation vignettes for the the TV channel, Redde Globe. Most recently, Biratan has published two books on the theme of ecology.
Sources: Cleaning up the seas by Bruce McKay and Kieran Mulvaney and Caretakers of the Sea by Jean-Pierre Levy.
From our website, see:
Feature: Seagrasses in deep trouble
Feature: Deadly red tides on the rise
Feature: Cleaning up the coasts
Feature: Oil and blood stain the waters of the Galapagos Islands
Feature: IUCN calls for better ocean governance
Feature: Cleaning up the seas
News: Ocean 'dead zones' suffocating marine life
News: Great Barrier Reef overloaded with pollutants
Factfile: Ocean pollution
Center for Marine Conservation
Coastal Resources Center
WWF's Endangered Seas Campaign
IUCN's Global Marine Programme
London Convention on the Prevention of Marine Pollution by Dumping of Waste
Marine Conservation Society
UN Atlas of the Oceans
World Conservation Monitoring Centre - Marine Programme