Feeds

Envisat could track coral bleaching

Climate change canary

Top three mobile application threats

The European Space Agency's Envisat satellite could be used to keep tabs on the state of the oceans' coral reefs, Australian researchers say.

Scientists from Australia's Commonwealth Scientific and Industrial Research Organisation's (CSIRO) Wealth from Oceans Flagship program say that the satellite's MERIS sensor can detect coral bleaching down to a depth of ten metres. In theory, the satellite could scan reefs worldwide on a fortnightly basis.

MERIS image of the Heron Island reef

The MERIS sensor takes multispectral optical pictures of Earth's oceans, land and atmosphere.

Normally the observations are made from boats, planes or helicopters, but this is a slow process, and many reefs are not easily accessible. Regularly collected data would be invaluable to researchers because bleaching events can happen quickly, and bleached coral is soon colonised by blue-green algae. This makes it hard to spot, the researchers say.

CSIRO's Dr. Arnold Dekker notes: "Coral bleaching needs to be mapped at the global scale. High-spatial resolution satellites can only do it on a few reefs due to cost and coverage constraints. We need a system that has appropriate coverage and revisit frequency, with a sufficient amount of spectral bands and sensitivity."

He argues that there is no system better suited to the task than the MERIS instrument.

When scanning in full resolution mode, the instrument is so sensitive that for each complete 300-metre pixel of coral under one metre of water it should be possible to detect a two per cent bleaching of live coral. Under ten metres of water, a bleaching of seven to eight per cent should still be detectable.

Coral bleaching is likely to be one of the first tangible effects of global warming, as it is closely linked to unseasonably high summer sea temperatures, and to solar radiation. Extensive bleaching events in 1998 and 2002 have been linked to the shifting El Niño current.

"The concern is that coral reefs might pass a critical bleaching threshold beyond which they are unable to regenerate," Dekker concludes. ®

3 Big data security analytics techniques

More from The Register

next story
KILLER SPONGES menacing California coastline
Surfers are safe, crustaceans less so
Opportunity selfie: Martian winds have given the spunky ol' rover a spring cleaning
Power levels up 70 per cent as the rover keeps on truckin'
Liftoff! SpaceX Falcon 9 lifts Dragon on third resupply mission to ISS
SpaceX snaps smartly into one-second launch window
LOHAN and the amazing technicolor spaceplane
Our Vulture 2 livery is wrapped, and it's les noix du mutt
KILLER ROBOTS, DNA TAMPERING and PEEPING CYBORGS: the future looks bright!
Americans optimistic about technology despite being afraid of EVERYTHING
R.I.P. LADEE: Probe smashes into lunar surface at 3,600mph
Swan dive signs off successful science mission
Discovery time for 200m WONDER MATERIALS shaved from 4 MILLENNIA... to 4 years
Alloy, Alloy: Boffins in speed-classification breakthrough
prev story

Whitepapers

Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Top three mobile application threats
Learn about three of the top mobile application security threats facing businesses today and recommendations on how to mitigate the risk.
Combat fraud and increase customer satisfaction
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.