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

 

Employment: ANZ Proposes Casualisation In Whangarei Stores

ANZ workers in Whangarei could see their incomes drop by 20 to 40 percent if the bank’s proposal to reduce the number of full-time positions goes ahead says FIRST Union national organiser Tali Williams. More>>

Finance: BNZ Develops Specialist Tāmaki Māori Banking Team

BNZ develops specialist Tāmaki Māori Banking Team to support Māori as Auckland grows More>>

Pharmaceuticals: Commerce Commission To Consider Pharmaceuticals Merger

The Commerce Commission has received an application from Pfizer Inc. seeking clearance to acquire all of the shares in Hospira Inc. More>>

Real Estate: Housing Unaffordability Issues Spread

Surging house prices in Auckland and Queenstown last month pushed home ownership even further beyond the reach of first home buyers in the two districts, according to the AMP360 Home Loan Affordability Report for March. More>>

Statistics NZ: Annual Exports To China Dip Below Australia

The value of goods exports to Australia ($8.7 billion) surpassed those to China for the year ended March 2015, Statistics New Zealand said today. More>>

Science: Hookworm Discovery At Malaghan Institute

Professor Graham Le Gros has led a team which has stimulated both innate and memory responses to the parasite, discovering along the way the unexpected behaviour of one particular immune cell, in Hookworm, one of the world’s most devastating tropical ... More>>

Business: Provinces Urged To Make Full Use Of New Air Services

Provincial New Zealand has been urged to use new air services to Auckland or risk losing them either partially or completely. The stark warning was issued today by Far North mayor John Carter at a ceremony at Kaitaia airport to mark the final Air ... More>>

Mobile: 2degrees To Credit All Calls And SMS To Nepal

In the wake of the devastating earthquake in Nepal in the weekend, 2degrees will be crediting all calls and SMS messages made to mobiles and landlines in Nepal from Friday 24th April until midnight Wednesday 29th April. More>>

Scoop Business: Alex Swney Pleads Guilty To $2.5M Fraud Charge

Alex Swney, former chief executive of the Auckland city centre business association Heart of the City, has pleaded guilty to dishonestly using documents to obtain $2.5 million. More>>

ALSO:

Petrol Burns Prices: Second Consecutive Quarterly Fall For CPI

The consumers price index (CPI) fell 0.3 percent in the March 2015 quarter, following a 0.2 percent fall in the December 2014 quarter, Statistics New Zealand said today. The last time the CPI showed two consecutive quarterly falls was in the December 1998 and March 1999 quarters. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news