In the past half billion years asteroid impacts and other natural events have caused five catastrophic mass extinctions of plants and animals.
Humans may be causing the sixth – and it’s our marine habitat that is most under threat.
Across the globe, research undertaken by the World Resources Institute and the Virginia Institute of Marine Sciences has identified more than 530 low oxygen ‘dead zones’ and an additional 228 sites that are suffering from severe over fertilisation by nutrients.
In the March issue of National Geographic, an article titled ‘Enter the Anthropocene Age of Man’ outlines the impact of a new geological era – one defined by our own massive impact on the planet.
Ours is an age where accelerated food production is creating far reaching side effects.
Fertilisers and pesticides make possible the high yields and flawless production we expect – but the nitrogen run-off is creating dead zones at the mouths of rivers worldwide.
According to the United Nations Environment Programme, we currently have two internationally recognised dead zones here in Australia – both in the Tasman Sea, off south eastern Australia.
And the problem is not confined to our oceans. There are also a number of dead zones in Australian river systems, estuaries and coastal lagoons such as the Swan River in Western Australia and Gippsland Lakes in Victoria.
Nor are we immune to the effects over-fertilisation – point sources such as sewage treatment plants, intensive agriculture and industry contribute between 5 and 35% of nutrients entering our waterways.
And don’t let us forget the estimated 80% of the rubbish found in concentrated areas such as gyres that comes from land based sources.
A major source of this plastic is land based stormwater pollution.
Entanglement is the most obvious consequence. Starvation is also documented.
What is less well known is the impact of chemical toxicity associated with plastics as they break up into smaller and smaller pieces.
As we celebrate World Water Day, Clean Up the World members around the globe are working to address the problem of rubbish in our watercourses, on our beaches and in our oceans through clean ups and educational initiatives.
Emirates Diving Association, Japan Environmental Education Network, The Royal Marine Conservation Society of Jordan, Legambiente in Italy and Canto Ecologico in Brazil – are just a few examples of the many organisations working with their communities to address this issue.
In 2010 Australians registered 1400 Clean Up Sites on beaches and waterways. In 2011 they were again one of our hotspots. And the most common item removed is plastic.
A healthy economy depends on a healthy environment; so it is vital that we get better protection mechanisms in place for the lifeblood of our planet – our waterways and the marine life they support.
As we celebrate World Water Day, my mission is to change the outcome of the ‘Anthropocene Age of Man’ – from one of extinction of our marine habitat to one where protection is the only accepted benchmark.
Clean Up the World congratulates our members who are already conducting activities to clean up waterways and oceans and encourages your group to join them through to the Clean Up the World Weekend on 16-18 September.
Ian Kiernan AO