Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Scientists To Probe Lake Rotomahana

MEDIA RELEASE from GNS Science, 15 NOVEMBER 2010

Scientists To Probe Lake Rotomahana’s Geothermal Vents

Scientists from the New Zealand and the United States are planning to use two torpedo-like unmanned underwater vehicles to map the
bottom of Lake Rotomahana, near Rotorua, and look for hydrothermal activity on the lake bed.

The project, scheduled to start in late January, will be the first time in New Zealand that a lake bed has been mapped by autonomous
underwater vehicles, or AUVs.

As well as producing a detailed three-dimensional map of the lake bed, the sophisticated sensors on the AUVs will enable the scientists
to locate hydrothermal vents at the bottom of the lake.

The present-day chemistry of the lake indicates that geothermal fluids are pouring into it from below Scientists are keen to find out the
number of vents on the lake bed, their locations, and the intensity of venting.

The project is a collaboration involving GNS Science, the Woods Hole Oceanographic Institute (WHOI) in the US, the University of Waikato,
and the Te Arawa Lakes Trust Board.

Lake Rotomahana, roughly 3km by 6km in size, enlarged in size after the eruption of Mt Tarawera in 1886, which is thought to have
destroyed and drowned the famed Pink and White Terraces. The Terraces, or their remnants, are believed to be buried at the bottom
of the lake.

The battery-powered AUVs will motor through the lake at about walking pace on a pre-programmed grid pattern to produce a highly
accurate three-dimensional view of the lake bed.

Other measurements they will take include temperature, pH, conductivity, depth, optical clarity of the water, and the electrical potential, or Eh,
of the lake water. The vehicles will also be able to map the magnetic signature of the volcanic rocks beneath the lake floor and are equipped
with side-scan sonar, which helps to distinguish different rock types.

Scientists will compile the data into a layered map of the lake bed which will elucidate the nature of the geology and hydrothermal
activity at Rotomahana.

Project leader, Cornel de Ronde of GNS Science, said there were very few examples of hydrothermal activity in freshwater lakes in the world,
and even fewer had been studied in detail.

“Our aim is to determine what happened to the Pink and White Terraces hydrothermal system when it was drowned in the enlarged
Lake Rotamahana soon after the 1886 eruption,” Dr de Ronde said.

“We also want to know what links there are between the drowned geothermal systems of Lake Rotomahana and the adjacent geothermal
system at Waimangu.

“This is a rare opportunity to document the death of a land-based geothermal system and its rebirth at the bottom of a lake.”

The accuracy of the mapping will enable the scientists to see features on the lake bed about the size of a suitcase.

When vents are located and given a GPS coordinate, scientists will lower instruments from a boat to determine temperature, flow rate,
and chemical composition of the vent fluids. This will help build a computer model of the hydrothermal and magma systems beneath the lake.

Prior to 1886, the Pink and White Terraces were considered an international marvel and were sometimes referred to the eighth natural
wonder of the world. They were the largest silica terraces in the world and represented an enormous outflow of geothermal fluid.

Scientists believe the Terraces, or their remnants, are today covered by at least 50m of lake water plus an additional unknown thickness
of sediment. Lake Rotomahana is 115m deep at its deepest point.

GNS Science, with the support of the Royal Society, will be offering activities to Rotorua primary and intermediate schools in connection
with this project. Information on the activities will be sent teachers in the Rotorua area this week.

END

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Sky City : Auckland Convention Centre Cost Jumps By A Fifth

SkyCity Entertainment Group, the casino and hotel operator, is in talks with the government on how to fund the increased cost of as much as $130 million to build an international convention centre in downtown Auckland, with further gambling concessions ruled out. The Auckland-based company has increased its estimate to build the centre to between $470 million and $530 million as the construction boom across the country drives up building costs and design changes add to the bill.
More>>

ALSO:

RMTU: Mediation Between Lyttelton Port And Union Fails

The Rail and Maritime Union (RMTU) has opted to continue its overtime ban indefinitely after mediation with the Lyttelton Port of Christchurch (LPC) failed to progress collective bargaining. More>>

Earlier:

Science Policy: Callaghan, NSC Funding Knocked In Submissions

Callaghan Innovation, which was last year allocated a budget of $566 million over four years to dish out research and development grants, and the National Science Challenges attracted criticism in submissions on the government’s draft national statement of science investment, with science funding largely seen as too fragmented. More>>

ALSO:

Scoop Business: Spark, Voda And Telstra To Lay New Trans-Tasman Cable

Spark New Zealand and Vodafone, New Zealand’s two dominant telecommunications providers, in partnership with Australian provider Telstra, will spend US$70 million building a trans-Tasman submarine cable to bolster broadband traffic between the neighbouring countries and the rest of the world. More>>

ALSO:

More:

Statistics: Current Account Deficit Widens

New Zealand's annual current account deficit was $6.1 billion (2.6 percent of GDP) for the year ended September 2014. This compares with a deficit of $5.8 billion (2.5 percent of GDP) for the year ended June 2014. More>>

ALSO:

Still In The Red: NZ Govt Shunts Out Surplus To 2016

The New Zealand government has pushed out its targeted return to surplus for a year as falling dairy prices and a low inflation environment has kept a lid on its rising tax take, but is still dangling a possible tax cut in 2017, the next election year and promising to try and achieve the surplus pledge on which it campaigned for election in September. More>>

ALSO:

Job Insecurity: Time For Jobs That Count In The Meat Industry

“Meat Workers face it all”, says Graham Cooke, Meat Workers Union National Secretary. “Seasonal work, dangerous jobs, casual and zero hours contracts, and increasing pressure on workers to join non-union individual agreements. More>>

ALSO:

Get More From Scoop

 
 
Standards New Zealand

Standards New Zealand
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news