Dust Is Good For Fishing

[shaune]

http://www.smh.com.au/environment/dust-was...91005-gjfd.html

Dust was blooming marvellous for harbour

DEBORAH SMITH SCIENCE EDITOR

October 6, 2009

THE thick blanket of red dust that settled on Sydney two weeks ago caused the harbour to bloom.

Nutrient-rich topsoil from the city's worst dust storm in about 70 years led to a tripling in the number of microscopic plants, or phytoplankton, in the upper layers of water, Sydney scientists have found.

They also calculate this invisible explosion in photosynthetic life in the harbour and Tasman Sea would have soaked up an amount of carbon dioxide equivalent to a month's emissions from the Munmorah Power Station on the Central Coast.

Ian Jones, head of the University of Sydney's ocean technology group, said Sydney coastal waters were low in nutrients such as nitrogen and phosphate that phytoplankton required to grow. ''We're sitting in an ocean desert in Australia,'' he said.

The results of the natural dust experiment were ''vindication'' for his team's controversial plans to nourish the ocean artificially with nitrogen-containing urea. He said this approach could not only help tackle climate change but also help feed the hungry or poor in countries such Morocco.

Phytoplankton growth increases fish production. ''If we continuously nourished a patch of water about 20 kilometres in diameter we could support poor artisan fisherfolk and we could raise their daily income from $1 to $2, while storing 10 million tonnes per year of carbon dioxide in the deep ocean,'' he said.

Like all plants, phytoplankton absorb this greenhouse gas from the environment, taking the carbon with them when they die and sink to the bottom.

Other scientists, however, have raised concerns about ocean fertilisation with nutrients such as iron. A recent report by the Royal Society in Britain concluded that, as a large-scale solution to climate change, it has ''a high potential for unintended and undesirable ecological side effects''.

The Sydney team has regularly tested for chlorophyll at Chowder Bay, home of the Sydney Institute of Marine Science, and at a site 10 kilometres offshore, to determine phytoplankton levels and the impact of events such as heavy rain.

The massive dust storm was a fortuitous case of the ''world collaborating with scientists'', Professor Jones said. The results would boost their case for an initial experiment to spread 2.5 tonnes of nitrogen, in the form of urea, in the Tasman Sea, which would need government approval to go ahead, he said. ''Our tests would be perfectly safe in an environmental sense.''

If they can work out an enviromentally freindly way of dump carbon in the ocean its a win win for fishos and greenies. I wonder what the "undesirable side effects are?"

[pjbink]

Australia's oceans aren't really 'deserts'. We are about average for warm temperate continental slopes. Primary productivity is compared in the graphs below (green bar) and is defined as the amount of carbon fixed per square meter. Also note how our fisheries harvest compares to other countries, keeping in mind the total EEZ and shelf areas (blue bars). This says something about the Greenies claims that our waters are overfished!

Edited October 6, 2009 by billfisher

[Scienceman]

I thought Australian soils were particularly low in phosphoros and nitrogen, which is why our native plants die when you use regular fertilizers, they have VERY active uptake mechanims for these nutrients becuase they are so deficient in the soil. We hardly have "nutrient rich" soils in central Australia where this dust came from.

Becase the land is low in these I think our oceans are also comparatively deficient too.

[pjbink]

I thought Australian soils were particularly low in phosphoros and nitrogen, which is why our native plants die when you use regular fertilizers, they have VERY active uptake mechanims for these nutrients becuase they are so deficient in the soil. We hardly have "nutrient rich" soils in central Australia where this dust came from.

Becase the land is low in these I think our oceans are also comparatively deficient too.

The primary productivity measurements look at the amount of carbon fixed per square meter of ocean surface, by the plankton. If there is any deficiency then it doesn't show up in these figures.