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  • Breath Of The Ocean Calls Fish

    These sulfur compounds are also known to serve as odor signals to marine organisms and are likely to play an equally important role in marine ecology, said Gabrielle Nevitt, professor of neurobiology, physiology and behavior at UC Davis and senior author on the study. The researchers wanted to know if reef fish also respond to these chemicals.

    DeBose released plumes of DMSP at low concentrations on reefs off the Caribbean island of Curacao, Netherlands Antilles.

    "It was pretty impressive," she said. "We would be surrounded by hundreds of fish for up to 60 minutes." The plumes mostly attracted fish known to feed on plankton, such as brown chromis and Creole wrasse, and the researchers noted that these fish were mostly arriving from down-current as if they were following a plume of scent.

    The fish are using scent to "listen" to the interaction between plant plankton and their predators, DeBose said.

    "They’re not smelling food, but other cues that might lead them to food," she said.

    DMSP is also given off by zooxanthellae, one-celled organisms that live inside coral polyps and allow them to photosynthesize. Stressed or damaged coral can lose its zooxanthellae and become "bleached," Nevitt said.

    "DMSP is the smell of a productive, healthy reef," she said.

    DMSP has mostly been studied in the context of atmospheric chemistry and global climate regulation, and not as a signaling molecule, Nevitt said. A better understanding of its effects could help in the recovery of damaged reefs, and understanding the links between climate change and the biological realm.

    Sean Lema, Assistant Professor of Biology and Marine Biology, Center for Marine Science of the University of North Carolina in Wilmington, is also an author on the paper, published in the March 7 issue of the journal Science. The work was funded by the American Museum of Natural History and the Philanthropic Educational Organization.

    Adapted from materials provided by University of California – Davis, via EurekAlert!, a service of AAAS.

  • Earthquakes to shake poles

    From New Scientist  

    CAN you put a freeze on earthquakes? It seems so, according to a computer model showing that earthquakes happen less often in areas covered by ice caps. Trouble is, quakes come back with a vengeance when the ice melts.

    Andrea Hampel at Ruhr University in Bochum, Germany, and colleagues wondered why Scandinavia experienced a surge in tectonic activity around 9000 years ago, whereas few earthquakes occur there today. They realised that the earthquake flurry coincided with the melting of the Fennoscandian ice sheet, which blanketed the area in the last ice age.

    To discover why, they devised a model to test how geological faults respond when buried beneath several hundred metres of ice. They found that the vertical stress placed on the Earth’s crust by a heavy ice sheet can suppress many types of fault from slipping and causing a quake.

    Though the faults are pinned down for a time, stresses in the crust continue to build, so when the ice melts, earthquakes occur more strongly and more frequently (Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2008.02.017). This has already been been observed in Alaska, says Hampel. She warns that Greenland and Antarctica could experience more earthquakes as their ice sheets disappear.

    From issue 2646 of New Scientist magazine, 08 March 2008, page 17

  • Ebono and Get Up make winning team

    Giovanni Ebono is a broadcaster and activist. He believes that online networks are a critical component in shaping a new, more representative democracy. He actively used the web, and multimedia to run his election campaign for the seat of Richmond in the last federal election. That campaign resulted in a significant swing towards the Greens, Richmond is now the sixth Greenest seat in the nation.

    You can view the remnants of that effort at the campaign website. As well as providing all media services online, he provided a range of resources for supporters and campaign workers and promoted them in print, on air and via  email networks.

     

     Catch Giovanni at work on credit card debt

    Ebono is currently completing work on the Wiley Publishing title World Poverty For Dummies and is actively involved in a number of campaigns to do with global economic justice. During the federal election Ebono promoted and drove domestic economic justice issues, pre-empting the mainstream media on a number of occasions. One of our regular media stunts was specifically on the topic of regulating personal credit and unscrupulous operators.

    He’s a publisher, broadcaster and producer with a background in publishing business and management titles. He’s also operated his own business for ten of the last twenty years and employed up to ten people. He’s actively involved in developing policy at the federal level with the NSW Greens.

    Ebono’s background is as a magazine editor at Australian Consolidated Press for seven years. He left to start a television show and online publishing company, delivered online content management systems to a range of publishers and industry associations and have since worked as a book publisher and editor. He uses digital techniques to produce a weekly radio show, online newsfeed with regular web based video and podcasts.

    Ebono has been living on the North Coast of NSW for four years, learning radio and sharpening up his public speaking and comedy skills. Now he’s moved back to Sydney, and seeks a role that integrates his passion for politics, broad general knowledge and range of media experience.

    He said, "I’m excited at the opportunity to work with Get Up. You are shaping the future of democracy and I would be honoured, excited and happy to be a part of the team."

    Download the application letter and resume .

  • Glaciers speed up 20 times

    From Science Daily  

    Boulders the size footballs could help scientists predict the West Antarctic Ice Sheet’s (WAIS) contribution to sea-level rise according to new research.

    Scientists from British Antarctic Survey (BAS), Durham University and Germany’s Alfred Wegener Institute for Polar and Marine Research (AWI) collected boulders deposited by three glaciers in the Amundsen Sea Embayment — a region currently the focus of intense international scientific attention because it is changing faster than anywhere else on the WAIS and it has the potential to raise sea-level by around 1.5 metres.

    Analysis of the boulders has enabled the scientists to start constructing a long-term picture of glacier behaviour in the region. An urgent task is to put recent ice sheet changes into a historical context, and determine if these are part of a natural retreat since the end of the last glacial period (about 20 thousands years ago), or if they are a result of recent human-induced climate change.

    Lead author Dr Joanne Johnson of BAS says, "Until now we didn’t know much about the long-term history of this part of the West Antarctic Ice Sheet because the region is incredibly remote and inaccessible. Our geological findings add a new piece to the jigsaw and will be used for improving computer models — the most important tools we have for predicting future change."

    Initial results show that Pine Island Glacier has ‘thinned’ by around 4 centimetres per year over the past 5,000 years, while Smith and Pope Glaciers thinned by just over 2 cm per year during the past 14,500 years. These rates are more than 20 times slower than recent changes: satellite, airborne and ground based observations made since the 1990s show that Pine Island Glacier has thinned by around 1.6 metres per year in recent years.

    The scientists reached their conclusions by investigating how long the boulders have been exposed to cosmic radiation rather than being shielded by ice or sediment.

    Co-author Dr Mike Bentley from the University of Durham said, "When rocks are left high and dry by thinning glaciers they are exposed to high energy cosmic rays which bombard the rock. This creates atoms of particular elements that we can extract and measure in the laboratory – the longer they have been exposed the greater the build-up of these elements. The discovery that we can place a fix on when rocks were left behind by the ice has revolutionised our understanding of how the Antarctic ice sheet has behaved in the past. "

    Collapse of West Antarctic Ice Sheet?

    The Amundsen Sea Embayment (ASE) lies on the side of the West Antarctic Ice Sheet (WAIS). It is an area that has always caused glaciologists concern, because here the bedrock beneath the ice is a long way below sea-level and the ice is only kept in place because it is thick enough to rest on the bed. Thinning of the ice around the coast could lead to glacier acceleration and further thinning of the ice sheet. Essentially, the ice sheet may be unstable, and the recent pattern of thinning could be a precursor to wholesale loss of the ASE ice sheet (implying a sea-level rise of around 1.5 m).

    Complete collapse of the WAIS would result in a rise of about 5 m in global sea level. Most scientists working in the area think that complete collapse within the next few hundred years is unlikely, but even loss of one sector of the ice sheet would imply that projections of sea-level rise are at present too low.

    Fieldwork

    The ASE is a notoriously difficult place in which to undertake fieldwork, it is cold, windy and is more than 1400 km from any research station.

    Using a helicopter from the German research vessel Polarstern during an expedition led by Karsten Gohl (AWI) BAS scientist Joanne Johnson and colleagues visited remote rock outcrops protruding from Pine Island, Pope and Smith glaciers on the vast West Antarctic Ice Sheet. They collected samples from boulders that have lain ice-free for thousands of years.

    Pine Island Glacier is of great interest to scientists worldwide as it has been thinning at a rate of more than 1 m/year and its flow rate has accelerated over the past 15 years. The location at which the glacier starts to float on the sea also retreated at a rate of more than 1 km/year during part of this period.

    Cosmogenic isotopes (eg Beryllium-10 and Aluminium-26) are created in rocks when they are bombarded by cosmic rays that penetrate the atmosphere from outer space. The accumulation of these isotopes within a rock surface can be used to establish its ‘surface exposure age’, i.e., how long it has been exposed to cosmic radiation rather than being shielded by ice or sediment. 

    Journal reference:  First exposure ages from the Amundsen Sea Embayment, West Antarctica: The Late Quaternary context for recent thinning of Pine Island, Smith and Pope Glaciers by Joanne S. Johnson, Michael J. Bentley and Karsten Gohl is published in the March issue of the journal Geology.

    Adapted from materials provided by British Antarctic Survey.

  • Tasmanians may pay for Gunns’ pipeline

    Tasmanian taxpayers could be slugged with a multi-million dollar bill for a pipeline used to supply water to the Gunns pulp mill planned for northern Tasmania.

    The Government is considering whether to declare the pipe to Trevallyn Dam a piece of critical state infrastructure, and pay for its construction.

    The Premier, Paul Lennon, says it could also be used by industry and farms to obtain more water for industrial and irrigation uses.

    He says the government may also build the effluent pipe from the mill to Bass Strait, which could be used to help dispose of sewage from Launceston.

  • Govt denies too much land clearing going on

    From the ABC  

    Conservationists say recent approvals to clear thousands of hectares in the Daly catchment are an indictment on the Territory Government’s pledge to halt clearing and protect the iconic region.

    In December, the Government extended its four year moratorium over land clearing in the Daly. On Friday, it committed to reducing greenhouse emissions.

    The World Wide Fund’s Dr Stuart Blanch says Nenen Station south of Katherine has been approved to clear over 3,000 hectares to sow introduced pastures for cattle grazing.

    Dr Blanch says there’s a worrying inequity between the area where clearing is banned under a government moratorium and where clearing has been approved next door.

    "Nenen Station is at the very southern end of the Daly River catchment. The Pastoral Lands Board has approved clearing of around 3,100 hectares that will lead to a carbon pollution event of around 400,000 to 500,000 tonnes of greenhouse gas emissions in the future."

    Dr Blanch says another almost 2,000 hectares of tree clearing in the Finniss River and Mataranka regions has also been approved so far this year. He says the clearing will release up to 140,000 tonnes of greenhouse gases to the atmosphere.

    "This seems to be at odds with the Chief Minister’s and Environment Minister’s clear signalling that we need to get cracking on reducing our greenhouse gas emissions.

    "There are some mixed messages coming out of Government on this."

    But Environment Minister Len Kiely has dismissed the accusation of inequity in the treatment of land clearing applications.

    Len Kiely says the Nenen approval was justified, though he wouldn’t comment on the atmospheric greenhouse gas emissions from the clearing.

    "As it stands right now, we will always assess any applications for land clearing against our very stringent land clearing guidelines which (look at) soil quality, water availability, biodiversity.

    "The Nenen clearance was made in accordance with land clearing guidelines … These were assessed and they were deemed OK.

    "We are proud as a Government to have extended the moratorium in the Daly. We believe it is the right decision for the Daly. We are using the Daly to get to gather the science on what it means to protect our iconic rivers in the north."

    The World Wide Fund Australia is calling for an embargo on all major land clearing across the Northern Territory to avoid panic land development.