Highest-ever winter water temperatures recorded

Aug 06, 2009
Highest-ever winter water temperatures recorded
NOAA polar orbiting satellites obtain the data generating sea surface temperature images. This is a composite 15-day image showing the extension of the Leeuwin Current around Tasmania. Photo by: CSIRO

(PhysOrg.com) -- Tasmania’s east coast is recording its highest-ever winter water temperatures of more than 13ºC - up to 1.5ºC above normal - due to a strengthening of an ocean current originating north of Australia.

Satellites have given oceanographers an insight into a remarkable phenomenon - a significant extension of the Leeuwin Current curling around the southern tip of Tasmania and reaching as far north as St Helens.

Remote sensing specialists at CSIRO's Wealth from Oceans Flagship have been observing the current in recent days using satellite data, and ocean measurements made near Maria Island on Tasmania’s east coast.

CSIRO oceanographers Katy Hill, David Griffin and George Cresswell study ocean behaviour in the Australian region. Dr Cresswell says that scientists use ocean observations from satellite, ocean instruments and research vessels - such as the Marine National Facility, RV Southern Surveyor - to track the currents but there are also other indicators such as tropical species reaching Tasmania.

“It’s important for us to monitor these changes in the ocean, as they can have consequences for marine ecosystems, fisheries, aquaculture, coastal communities and more,” Dr Cresswell says.

The Leeuwin Current forms north of Australia and flows right around the western half of the country, meeting its better known cousin, the East Australian Current (EAC), at Tasmania. The exact location of this meeting point varies both seasonally and from year-to-year, depending on how strongly each current is flowing.

Oceanographers believe the EAC has gradually been getting stronger, and the Leeuwin Current weaker. Changes in the EAC are among the most significant in the global ocean, with a continuous record of monthly measurements one of Australian oceanography’s most valuable indicators for climate and .

Observations of temperature, salinity and nutrients have been collected monthly just east of Maria Island since 1944, showing how the influence of both the EAC and Leeuwin Current systems varies in Tasmanian waters. As part of the Integrated Marine Observing System (IMOS), a National Reference Station mooring has been deployed at the same site, and data is now available online every 10 minutes. Monthly samples are taken by boat to measure nutrients, phytoplankton, and zooplankton (biomass and species composition).

Satellite images indicate the surface water temperature over the continental shelf current is around 13 degrees, a degree or two warmer than at this time in recent years. The EAC has been a research focus for Katy Hill since 2005 as part of her PhD in the Quantitiative Marine Science program - a joint initiative of CSIRO and the University of Tasmania.

The St Helens-based Chief Executive of the Tasmanian Rock Lobster Association, Rodney Treloggen, said he was not aware of any reports of Indian Ocean species but he said fishers were concerned at what he described as a “bad year” for the industry in the south-east and east coast.

"We know the warmer waters have an impact but we're not sure how much," Mr Treloggen said.

Provided by CSIRO (news : web)

Explore further: How productive are the ore factories in the deep sea?

add to favorites email to friend print save as pdf

Related Stories

'Ocean glider' home after two-month voyage

Apr 16, 2009

Scientists are celebrating the first successful deployment and retrieval in Australia of a remotely controlled, deep ocean-going robotic submarine destined to play a central role in measuring changes in two ...

Ocean 'supergyre' link to climate regulator

Aug 15, 2007

Australian scientists have identified the missing deep ocean pathway – or ‘supergyre’ – linking the three Southern Hemisphere ocean basins in research that will help them explain more accurately how ...

Fish growth changes enhanced by climate change

Apr 27, 2007

Changes in growth rates in some coastal and long-lived deep-ocean fish species in the south west Pacific are consistent with shifts in wind systems and water temperatures, according to new Australian research published in ...

Giant ocean eddy shadows Sydney

Mar 25, 2008

The giant ocean eddy that cooled Sydney's shores a year ago has been superseded by another 300 km diameter giant.

Recommended for you

How productive are the ore factories in the deep sea?

16 minutes ago

About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ...

NASA image: Volcanoes in Guatemala

4 hours ago

This photo of volcanoes in Guatemala was taken from NASA's C-20A aircraft during a four-week Earth science radar imaging mission deployment over Central and South America. The conical volcano in the center ...

NASA sees last vestiges of Tropical Depression Jack

22 hours ago

Tropical Cyclone Jack had weakened to a tropical depression when NASA and JAXA's Tropical Rainfall Measuring Mission (TRMM) satellite passed above on April 22, 2014 at 1120 UTC/7:20 a.m. EDT.

User comments : 0

More news stories

Sea floor conditions mimicked for drilling platforms

Mobile jack-up drilling platforms used in the oil and gas industry are at risk of rejection before installation due to their use in harsher environments and deeper waters—but University of WA scientists ...

New breast cancer imaging method promising

The new PAMmography method for imaging breast cancer developed by the University of Twente's MIRA research institute and the Medisch Spectrum Twente hospital appears to be a promising new method that could ...

Research proves nanobubbles are superstable

The intense research interest in surface nanobubbles arises from their potential applications in microfluidics and the scientific challenge for controlling their fundamental physical properties. One of the ...

Using antineutrinos to monitor nuclear reactors

When monitoring nuclear reactors, the International Atomic Energy Agency has to rely on input given by the operators. In the future, antineutrino detectors may provide an additional option for monitoring. ...