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  • Response of benthic foraminifera to ocean acidification in their natural sediment environment: a long-term culturing experiment

    Response of benthic foraminifera to ocean acidification in their natural sediment environment: a long-term culturing experiment

    Published 16 June 2013 Science Leave a Comment
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    Calcifying foraminifera are expected to be endangered by ocean acidification, However, the response of a complete community kept in natural sediment and over multiple generations under controlled laboratory conditions has not been constrained to date. During six month incubation, foraminiferal assemblages were treated with pCO2 enriched seawater of 430, 907, 1865 and 3247 μatm pCO2. The fauna was dominated by Ammonia aomoriensis and Elphidium species, whereas agglutinated species were rare. After 6 months incubation, pore water alkalinity was much higher in comparison to the overlying seawater. Consequently, the saturation state of Ωcalc was much higher in the sediment than in the water column in all pCO2 treatments and remained close to saturation. As a result, the life cycle of living assemblages was largely unaffected by the tested pCO2 treatments. Growth rates, reproduction and mortality, and therefore population densities and size-frequency distribution of Ammonia aomoriensis varied markedly during the experimental period. Growth rates varied between 25 and 50 μm per month, which corresponds to an addition of 1 or 2 new chambers per month. According to the size-frequency distribution, foraminifera start reproduction at a diameter of 250 μm. Mortality of large foraminifera was recognized, commencing at a test size of 285 μm at a pCO2 ranging from 430 to 1865 μatm, and of 258 μm at 3247 μatm. The total organic content of living Ammonia aomoriensis has been determined to be 4.3% of dry weight. Living individuals had a calcium carbonate production rate of 0.47 g m−2 yr−1, whereas dead empty tests accumulated at a rate of 0.27 g m−2 a−1. Although Ωcalc was close to 1, some empty tests of Ammonia aomoriensis showed dissolution features at the end of incubation. In contrast, tests of the subdominant species, Elphidium incertum, stayed intact. This species specific response could be explained by differences in the elemental test composition, in particular the higher Mg-concentrations in Ammonia aomoriensis tests. Our results emphasize that the sensitivity to ocean acidification of endobenthic foraminifera in their natural sediment habitat is much lower compared to the experimental response of specimens isolated from the sediment.

     

    Haynert K., Schönfeld J., Schiebel R., Wilson B. & Thomsen J., 2013. Response of benthic foraminifera to ocean acidification in their natural sediment environment: a long-term culturing experiment. Biogeosciences Discussions 10: 9523-9572. Article.

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  • Antarctic Ice Shelves Losing Mass As A Result Of The Undersides Melting — Not Iceberg Calving As Was Previously Thought

    Antarctic Ice Shelves Losing Mass As A Result Of The Undersides Melting — Not Iceberg Calving As Was Previously Thought

    Posted on June 15, 2013 by
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    The Antarctic ice shelves have been melting at ever increasing rates in recent years — losing mass, though not always extent, as much of the mass loss has been with regards to ice thickness. And now, new research has shed some new light on the causes of this ice loss — the warming ocean waters have been melting the ice shelves from underneath, it’s not primarily the result of icebergs calving into the ocean as was previously thought.

    "Aerial photo of front of Venable Ice Shelf, West Antarctica, an example of a small ice shelf that is a large meltwater producer. Such ice melts are far more common than previously thought and will change predictions about the thawing continent. Taken onboard the Chilean Navy P3 aircraft during the NASA/Centro de Estudios Cientificos fall 2008 campaign." Image Credit: NASA/JPL-Caltech/UC Irvine

    “Aerial photo of front of Venable Ice Shelf, West Antarctica, an example of a small ice shelf that is a large meltwater producer. Such ice melts are far more common than previously thought and will change predictions about the thawing continent. Taken onboard the Chilean Navy P3 aircraft during the NASA/Centro de Estudios Cientificos fall 2008 campaign.”
    Image Credit: NASA/JPL-Caltech/UC Irvine

    The new research — representing the first comprehensive survey of all Antarctic ice shelves — has found that basal melt (ice dissolving from underneath) was responsible for 55% of all ice shelf loss from 2003 to 2008. That is a much higher rate than was previously assumed. As a reminder of why this matters — ice shelves, which are essentially the floating extensions of glaciers, surround 75% of the absolutely enormous frozen continent.

    The researchers think that this new work will allow others in the field to “improve projections of how Antarctica, which holds about 60% of the planet’s fresh water locked in its massive ice sheet, will respond to a warming ocean and contribute to sea level rise.” How the ice sheets of Antarctica will respond to the significant warming that is predicted to occur over the next 100 years is an important question — one which is especially important when you consider that the vast majority of the world’s most important economic regions are relatively close to coastlines. Rising seas as well as increasing flood/storm events could have devastating consequences for many of the world’s largest economies.

    Back to the research — as the researchers put it “it turns out that the tug of seawaters just above the freezing point matters more than the breaking off of bergs.”

    “We find that iceberg calving is not the dominant process of ice removal. In fact, ice shelves mostly melt from the bottom before they even form icebergs,” explained lead author Eric Rignot, a UC Irvine professor, and also a researcher at NASA’s Jet Propulsion Laboratory. “This has profound implications for our understanding of interactions between Antarctica and climate change. It basically puts the Southern Ocean up front as the most significant control on the evolution of the polar ice sheet.”

    The press release provides context and details:

    Ice shelves grow through a combination of land ice flowing to the sea and snow falling on their surfaces. The researchers combined a regional snow accumulation model and a new map of Antarctica’s bedrock with ice shelf thickness, elevation and velocity data captured by Operation IceBridge — an ongoing NASA aerial survey of Greenland and the South Pole.

    Ocean melting is distributed unevenly around the continent. The three giant ice shelves of Ross, Filchner and Ronne, which make up two-thirds of Antarctica’s ice shelves, accounted for only 15 percent of the melting. Meanwhile, less than a dozen small ice shelves floating on relatively warm waters produced half the total meltwater during the same period.

    The researchers also compared the rates at which the ice shelves are shedding ice with the speed at which the continent itself is losing mass and found that, on average, the shelves lost mass twice as fast as the Antarctic ice sheet did.

    “Ice shelf melt can be compensated by ice flow from the continent,” Rignot said. “But in a number of places around Antarctica, they are melting too fast, and as a consequence, glaciers and the entire continent are changing.”

    While rising sea levels are themselves an issue, the real issue — and one that is not often mentioned — is that as sea levels rise, more and more economically and industrially important infrastructure will be exposed to storm and flood events. Events similar to Hurricane Sandy, to Hurricane Katrina, could become very common — that would have a devastating effect on the economies of the affected regions. Something to keep in mind…

    The new research was just published in the June 14 issue of Science.

    Read more at http://planetsave.com/2013/06/15/antarctic-ice-shelves-losing-mass-as-a-result-of-the-undersides-melting-not-iceberg-calving-as-was-previously-thought/#BGPyqTB8cwhPRcMH.99

  • My party causing ‘panic’ in Labor: Palmer

    My party causing ‘panic’ in Labor: Palmer

    AAPUpdated June 16, 2013, 2:59 pm

    Speculation hanging over Labor’s leadership is the result of “panic” at the prospect of facing the Palmer United Party, according to the party’s billionaire leader Clive Palmer.

    He said a leadership change could lead to an early election that would prevent the Palmer United Party being registered in time.

    “Kevin Rudd would like to call the election earlier so they can stop our party from being registered federally,” Mr Palmer said.

    “If they can issue the writs by the 3rd of July and have an election in August they haven’t got to face it and people don’t get a choice.”

    The businessman said his party will run candidates in all 150 lower house seats as well as the senate and will provide a “genuine alternative” to the two major parties.

    “They know we’ll be standing in 150 seats and they’re starting to panic.”

    Mr Palmer also said if he was elected to the top job, he would likely only stay for a single term.

    “If I’m elected as prime minister I’ll only be there for three years,” he said.

    “I don’t want to stay there and go there. I’m going out there as a sense of duty.”

    Mr Palmer was in Melbourne on Sunday to announce the Victorian candidates for the Palmer United Party.

    They included a nervous Joe Zappia who will be campaigning against Prime Minister Julia Gillard in the west Melbourne seat of Lalor.

    Mr Zappia stuttered through a short speech in which he confused the name of the party he was representing.

    “The Palmer Liberal … I’ve never done this before and I’m not here to read these sort of things,” Mr Zappia said.

    “I will get better at this but the nerves are unbelievable at the moment.

    “Sorry for what I’ve done to you today.”

    He joins Victorian senate candidate former AFL great Doug Hawkins.

  • O’Farrell to budget for $4b north-west rail link

    O’Farrell to budget for $4b north-west rail link

    Date
    June 16, 2013 – 2:29PM
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    The NSW government will spend $4 billion to develop Sydney’s North West Rail Link, which is due to be running in 2019.

    About $800 million will be set aside in the 2013-2014 state budget, due to be handed down on Tuesday, the NSW premier, treasurer and transport minister announced on Sunday.

    The rest of the government money will flow over the next four years and the remaining $4.3 billion needed for the project will come from private tenders.

    As part of the project, eight new train stations will be built at Cherrybrook, Castle Hill, Showground, Norwest, Bella Vista, Kellyville, Rouse Hill and Cudgegong Road along with 4000 commuter car parking spaces.

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    A train will run down the line every five minutes in peak hour and high-frequency single deck trains will operate between Cudgegong Rd and Chatswood.

    Treasurer Mike Baird said the funding would also be used to buy property where necessary.

    Premier Barry O’Farrell said the rail link will provide “high capacity public transport to Sydney’s northwest for the first time”, and work on it should begin next year.

    It will benefit the NSW economy to the tune of $35 billion over the next few decades, he said.

    Transport Minister Gladys Bereljiklian said the rail link “will forever change the face of the north west”.

    Three major contracts for the construction of the line are still to be awarded.

    In coming months, the government expects to announce who has won the tender to construct 15 kilometres of twin tunnels between Epping and Bella Vista – the longest rail tunnels in the nation.

    Contracts to develop a four-kilometre “skytrain” section and operate it are also yet to be awarded.

    AAP

    Read more: http://www.smh.com.au/nsw/ofarrell-to-budget-for-4b-northwest-rail-link-20130616-2oc1z.html#ixzz2WMFMPQa4

  • Jim Hansen: Climate Change is the GOP’s worst nightmare

    Posted June 13, 2013, 5:14 pm MT

    Jim Hansen: Climate Change is the GOP’s worst nightmare

    Many conservative politicians have been among deniers, but ignoring the science will led to something the GOP dreads even more — big government.

    So argued Jim Hansen, who since 1988 has been in the forefront of the issue, first as a NASA scientist and more recently as a free-agent activist, in an interview Thursday.

    After an ill-fated, and it could be argued ill-conceived, attempt to pass climate legislation in the first year the the Obama administration there has been little traction on the issue. The federal Environmental Protection Agency is delaying its rules on carbon dioxide emissions from power plants and the new Department of Energy energy efficiency standards for appliances are also being delayed.

    And that’s okay with Hansen, who says he sees the solution coming in a different form, a carbon tax, and from a different place — the right of the political spectrum.

    “It has to be a carbon tax and it really has to come from conservatives,” Hansen said. The reason is that the tax has to be market-based and revenue neutral.

    “That money has to be given back to the public on a per capita basis so all legal residents of the country get an equal amount and that way the person who does better than average in limiting their carbon footprint would make money and then everybody in the country becomes an environmentalists whether they want to or not,” Hansen said.

    “The fundamental fact is that as long as fossil fuels appear to the public to be the cheapest energy we are going to keep burning them,” Hansen said.”Fossil fuels are not the cheapest energy they only appear to be because they are subsidized.”

    California Democratic Sen. Barbara Boxer and Sen. Bernie Sanders, a Vermont independent, have introduced a bill that would create a carbon tax, but that doesn’t make Hansen happy.

    “As usual the Democrats are going to take some of the money, 40 percent of it,” Hansen said. “Conservatives have to put ta foot down and say you can’t use this as another excuse to make government bigger. Democrats have a problem they can’t keep their hands off our wallets.”

    The reason Hasen is so adamant is by his calculation if the government keeps 40 percent most people will end-up paying more for energy than they get back. “It is important that all the money go to the public, so get this push from below,” he said.

    What of the general reluctance from anyone — and we mean just about anyone — on the GOP side of the aisle to take up the issue since Arizona Sen. John McCain and South Carolina Sen. Lindsay Graham abandoned their 2008 efforts to fashion bipartisan legislation?

    “If they continue to pretend that human-made climate change is a hoax, eventually you get to the point where nature makes it clear it wasn’t a hoax and then the public demands the government do something and that’s the worst nightmare for conservatives,” Hansen said.

    “It would allow the government to take over and do things by fiat, which not in anybody’s interest in my opinion, because the government never, seldom, makes the right choices,” Hansen said. “Let the market make the choices, which is a conservative approach.”

  • Glacier melt causes third of sea-level rise

    Glacier melt causes third of sea-level rise

    Friday, 17 May 2013
    AFP

    Columbia Glacier

    Columbia Glacier: The most significant ice losses occurred in Arctic Canada, Alaska, coastal Greenland, the southern Andes and the Himalayas (University of Colorado)

    Big melt Water from the world’s shrinking glaciers was responsible for almost a third of the rise in sea levels between 2003 and 2009, shows new research.

    An international team of scientist compared data gleaned from two NASA satellites as well as traditional ground measurements from glaciers around the world.

    Their work, published in the journal Science , is the most accurate estimation of how glaciers contribute to sea level rises to date.

    “For the first time, we’ve been able to very precisely constrain how much these glaciers as a whole are contributing to sea rise,” says lead author Assistant Professor Alex Gardner, assistant geography professor at Clark University in Worcester, Massachusetts.

    “These smaller ice bodies are currently losing about as much mass as the ice sheets.”

    The most significant ice losses occurred in Arctic Canada, Alaska, coastal Greenland, the southern Andes and the Himalayas, the study found.

    The glaciers outside of the Greenland and Antarctic sheets lost an average of roughly 260 billion metric tons of ice annually during the period, leading to a rise in ocean levels of about 0.7 millimeters per year.

    By contrast the glaciers in Antarctica, smaller ice masses that are not connected to the ice sheet, made scarcely any contribution to sea-level rise over the study period.

    “Because the global glacier ice mass is relatively small in comparison with the huge ice sheets covering Greenland and Antarctica, people tend to not worry about it,” says Tad Pfeffer, a glaciologist of the University of Colorado at Boulder.

    “But it’s like a little bucket with a huge hole in the bottom: it may not last for very long, just a century or two, but while there’s ice in those glaciers, it’s a major contributor to sea level rise.”

    Scientists estimate that if all the glaciers in the world were to melt, sea levels would rise by about 60 centimetres.

    However if the entire ice sheet of Greenland were to vanish, the oceans would surge by six metres. If the Antarctic lost its ice cover, levels would rise about 60 metres.

    The study used data from NASA’s Ice, Cloud and Land Elevation Satellite, or ICESat, and the Gravity Recovery and Climate Experiment, or GRACE.

    ICESat, which ceased operation in 2009, tracked glacier changes by bouncing laser pulses off the surface to calculate the shifting height of ice cover.

    The GRACE system works by monitoring variations in Earth’s gravity field caused by shifts in the planet’s mass distribution, including displacements of ice.

    “Because the two satellite techniques are subject to completely different types of errors, the fact that their results are in such good agreement give us increased confidence in those results, says study author Professor John Wahr, also from the University of Colarado.

    Tags: climate-change