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

 


Tangaroa To Study How Antarctica Affects Ocean Currents

NIWA’s Tangaroa Sets Sail To Study How Antarctica Affects Ocean Currents

A team of 22 Australian, New Zealand and French scientists will depart Wellington next week, onboard NIWA’s RV Tangaroa, for a 42-day voyage to the Mertz Polynya region of Antarctica.

In 2010, the tongue of Antarctica’s Mertz Glacier was rammed by a huge iceberg, causing much of the tongue to break away. Scientists want to study the impact of this massive change to the Mertz Glacier on the surrounding environment.

This region is one of three unique places around Antarctica which control the properties of the deep ocean - thus the breaking ice tongue could have wider impacts on global ocean circulation. To study the changes in the ocean, the scientists will use a suite of underwater cameras, moorings and sensors.

NIWA oceanographer and voyage leader Dr Mike Williams says, “The Mertz Polynya is an ideal study site as it has had a big change to a small region, with potentially global implications, yet it is a small enough area that can be studied in a single voyage.”

The voyage is part of the research program of the Antarctic Climate and Ecosystems Cooperative Research Centre, based in Hobart, in which NIWA is a core partner.

Dr Williams says, “This is part of long-term research programme in this region, where we need to keep monitoring to keep track of the rate of change.”
Why this spot?
The Mertz Polynya is one of three places in the world where the densest ocean waters form.

“One of the aims of this voyage is to understand how the ice tongue breaking off has changed the polynya and hence how much dense water is formed there. We also hope to map the seafloor and reveal the area under the glacier tongue for the first time,” says Dr Williams.

A polynya is an area of open water surrounded by sea ice. Polynyas are kept free of sea ice by the wind, which constantly blows away any ice that tries to form. The formation of sea ice creates heavier saltier water, which then sinks.

“In the Mertz Polynya region the seafloor is like a bowl under the ocean, catching all this salt. Then that basin overflows down into the deep ocean. It’s like a dam overflowing after heavy rain,” says Dr Williams.

Antarctic bottom water is the densest in the ocean, so it spreads to fill the bottom of the global ocean. This means it has a significant influence on global ocean circulation.

“One of the aims of this research is to understand how changes in polynyas will affect the flow in the deep ocean,” says Dr Williams.

“By comparing the new measurements to previous observations, we will determine how the temperature, salinity and circulation of the Southern Ocean are changing.”

Dr Steve Rintoul is the leader of the Australian team on the voyage. “Our earlier research in this region has shown that rapid changes are underway in the deep ocean, but we are not yet sure what is driving the changes. The measurements collected on the Tangaroa voyage will be used to test the hypothesis that increased melt of Antarctic ice is driving changes we see in the deep ocean,” Dr Rintoul said.
Sampling the sea floor
Sedimentary cores will be retrieved from the seafloor using a long metal cylinder, which is lowered to the ocean floor and then pushed into the sediment under a heavy weight.

NIWA geologist Dr Helen Bostock says, “These sediment cores are archives of past changes in the ocean. The data from cores provides clues as to how the ocean temperature, nutrients, biological productivity, and sea ice extent have changed over thousands of years.”
Climate change
“We will be monitoring the surface ocean CO2 and the atmospheric CO2 on the transit across the Southern Ocean,” says Dr Williams.

Samples will also be collected in the water column. This will measure how much CO2 is being stored in the deeper waters.

Scientists will be looking at how much carbon is going into the deep ocean, and provide evidence for ocean acidification. Ocean acidification is the result of increased CO2 in the water, which reduces the pH and affects the ability of some organisms to form their carbonate skeletons.

Dr Bostock says, “Models have suggested that by as early as 2030, the surface of the Southern Ocean will be under-saturated with respect to some minerals that organisms use for their shells. This could have a significant impact on the types of organisms that live in the Southern Ocean.”

Scientists will be sampling for plankton using a continuous plankton recorder and plankton nets. The purpose of these surveys is to map the patterns over time, and then to use the sensitivity of plankton to environmental change as early warning indicators of the health of the Southern Ocean.

These observations and samples will augment ongoing Sub-Antarctic and Southern Ocean research programmes. This research is funded by the Australian Antarctic Climate and Ecosystem Cooperative Research Centre, the French Laboratoire d’Océanographie et du Climat (Locean), and NIWA through its government-funded core research.

To follow the Tangaroa visit:
https://www.niwa.co.nz/vessels/rv-tangaroa/location

Information about multibeam:
https://www.niwa.co.nz/our-services/instruments/instruments/em300

Ocean acidification:
https://www.niwa.co.nz/our-science/oceans/research-projects/all/effects-of-ocean-acidification-on-plankton-in-new-zealand-waters

To follow the voyage:
http://sciblogs.co.nz/fieldwork/

ENDS

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Half Empty: Fonterra's 2017 Opening Forecast Below Expectations

Fonterra Cooperative Group raised its forecast farmgate milk payout for next season by less than expected as the world's largest dairy exporter predicts lower prices will crimp production and supply will pick up. The New Zealand dollar fell. More>>

ALSO:

Pest Control: Mouse Blitz Team Leaves For Antipodes

The Million Dollar Mouse project to rid Antipodes Island of mice is underway with the departure of a rodent eradication team to the remote nature reserve and World Heritage Area. More>>

Gongs Got: Canon Media Awards & NZ Radio Awards Happen

Radio NZ: RNZ website The Wireless, which is co-funded by NZ On Air, was named best website, while Toby Manhire and Toby Morris won the best opinion general writing section for their weekly column on rnz.co.nz and Tess McClure won the best junior feature writer section. More>>

ALSO:

Pre-Budget: Debt Focus Risks Losing Opportunity To Stoke Economy

The Treasury is likely to upgrade its forecasts for economic growth in Budget 2016 next week but Finance Minister Bill English has already signalled that more of his focus is on debt repayment than on fiscal stimulus or tax cuts... More>>

ALSO:

Fulton Hogan's Heroes: Managing Director Nick Miller Resigns

Fulton Hogan managing director Nick Miller will leave the privately owned construction company after seven years in charge. The Dunedin-based company has kicked off a search for a replacement, and Miller will stay on at the helm until March next year, or until a successor has been appointed and a transition period completed. More>>

ALSO:

Gordon Campbell: On Electricity, Executions, And Bob Dylan

The Electricity Authority has unveiled the final version of its pricing plan for electricity transmission. This will change the way transmission prices (which comprise about 10% of the average power bill) are computed, and will add hundreds of dollars a year to power bills for many ordinary consumers. More>>

ALSO:

Half Empty: Fonterra NZ, Australia Milk Collection Drops In Season

Fonterra Cooperative Group says milk collection is down in New Zealand and Australia, its two largest markets, in the first 11 months of the season during a period of weak dairy prices. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news