Plastic waste heading for oceans quantified

About eight million tonnes of plastic waste find their way into the world's oceans each year, say scientists.

Any walk along a beach will produce a sizeable haul of plastic waste

The new study is said to be the best effort yet to quantify just how much of this debris is being dumped, blown or simply washed out to sea.

Eight million tonnes is like covering an area 34 times the size of New York's Manhattan Island to ankle depth.

The details were released at the annual meeting of the American Association for the Advancement of Science (AAAS).

Dr Jenna Jambeck, the study’s lead author from the University of Georgia, had another way to try to visualise the scale of the problem.

The quantity entering the ocean is equal to about five plastic grocery bags full of plastic for every foot of coastline in the world,” she told BBC News.

Unseen pollution

Researchers have for some time now reported on the mass of plastic caught up in ocean currents, just going round and round.

What is slightly shocking about this new study, also published in Science Magazine, is that it helps quantify all the plastic in our oceans - not just the material seen floating on the sea surface or sitting on beaches.

The newly published estimate is 20 to 2,000 times greater than the reported mass of plastic trapped in high concentration in ocean gyres.

It is clear now that large quantities of debris must be hidden on the seafloor or have been weathered into tiny fragments that are just not apparent to casual surveys. The latter are being ingested by marine animals with unknown consequences.

Plastics will break down into tiny, persistent fragments that can then be ingested by animals

In doing its analysis, the team pulled together international data on population, waste generation and management (and mismanagement). The group then modelled scenarios for the likely sums of plastic getting into the ocean environment.

For 2010, the estimated range runs from 4.8 to 12.7 million tonnes. Eight million tonnes is the mid-scenario. It is a few percent of the total plastic waste generated that year.

In doing its analysis, the team pulled together international data on population, waste generation and management (and mismanagement). The group then modelled scenarios for the likely sums of plastic getting into the ocean environment.

For 2010, the estimated range runs from 4.8 to 12.7 million tonnes. Eight million tonnes is the mid-scenario. It is a few percent of the total plastic waste generated that year.

Jenna Jambeck's study tries to quantify the inputs. It is not a census of what is out there

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From BBC News

Blast fishing destroying Tanzania's marine habitats

The rich marine life off Tanzania's coast is coming under threat because of blast fishing, according to environmentalists.

The technique sees fishermen use explosives to maximise their catch.

Although illegal, the practice is used along the entire Tanzanian coastline from Mtwara to Tanga, and off north Zanzibar.

From BBC News

Australian mammals on brink of 'extinction calamity'

Australia has lost one in ten of its native mammals species over the last 200 years in what conservationists describe as an "extinction calamity".

The endangered northern quoll, a mammal species native to Australia

No other nation has had such a high rate of loss of land mammals over this time period, according to scientists at Charles Darwin University, Australia.

The decline is mainly due to predation by the feral cat and the red fox, which were introduced from Europe, they say.Large scale fires to manage land are also having an impact.

As an affluent nation with a small population, Australia's wildlife should be relatively secure from threats such as habitat loss.But a new survey of Australia's native mammals, published in the journalProceedings of the National Academy of Sciences, suggests the scale of the problem is more serious than anticipated.

Since 1788, 11% of 273 native mammals living on land have died out, 21% are threatened and 15% are near threatened, the study found. Marine mammals are faring better.

Shy species

"No other country has had such a high rate and number of mammal extinctions over this period, and the number we report for Australia is substantially higher than previous estimates," said conservation biologist John Woinarski, who led the research.

"A further 56 Australian land mammals are now threatened, indicating that this extremely high rate of biodiversity loss is likely to continue unless substantial changes are made.

"The extent of the problem has been largely unappreciated until recently because much of the loss involves small, nocturnal, shy species with [little] public profile - few Australians know of these species, let alone have seen them, so their loss has been largely unappreciated by the community."

The brush-tailed rabbit-rat, a mammal species native to Australia that is listed as a near-threatened species by the International Union for Conservation of Nature

In time, iconic species such as the koala will also decline, said the researchers, from Charles Darwin University, Southern Cross University and the Department of Parks and Wildlife in Wanneroo.

The prospects for Australia's wildlife can be improved but is "a very formidable challenge", they added.

It is estimated there are between 15 and 23 million wild cats living on the continent.

Practical measures to protect native species include boosting biosecurity on islands off the mainland, which have fewer feral cats and foxes.

The islands could also act as arks for endangered species, while more careful use of fire and control measures to wipe out foxes and feral cats are also being considered.

But the researchers warn that Australians may ultimately need to consider the way they live on the land to stem the loss of natural assets.

FRom BBC News

There's confidence about the future of the Tasmanian devil (Simon Cullen - ABC News)

Brigitte Stevens from the Wombat Awareness Organisation with rescued wombats. pic Calum Robertson Picture: Calum Robertson