|
Getting your Trinity Audio player ready...
|
In a pioneering venture merging cutting-edge satellite technology and marine exploration, an extensive Australian-led research expedition has unravelled the mysteries hidden within the formidable Southern Ocean. Spanning a colossal 20,000 square kilometres between Tasmania and Antarctica, this zone has been meticulously charted in high resolution, unveiling a dynamic and energetic ‘hotspot’ nestled within the world’s mightiest current.
The remarkable FOCUS voyage aboard the CSIRO research vessel (RV) Investigator embarked on a five-week journey, delving into the heart of the Antarctic Circumpolar Current. Their mission is to comprehend the intricate dynamics of heat transfer across this natural boundary, shedding light on its role in the gradual melting of Antarctic ice shelves and the looming spectre of rising sea levels.
A groundbreaking aspect of this expedition was its synergy with the Surface Water and Ocean Topography (SWOT) satellite, a collaborative marvel forged by NASA and the French space agency CNES. This partnership facilitated simultaneous mapping of intricate oceanic features from both satellite and ship, offering an unprecedented understanding of this enigmatic domain.
Dr Benoit Legresy, the voyage’s chief scientist, emphasised the urgency of deciphering the complex web of heat distribution and carbon pathways within our climate system. “The ocean, serving as a crucial ‘climate shock absorber,’ has absorbed over 90% of global warming-induced heat and a quarter of human-generated CO2 emissions,” Dr. Legresy stated. “Deciphering these mechanisms becomes imperative in confronting human-induced climate change.”
Beyond merely tracing currents, the expedition’s groundbreaking mapping of the seafloor revealed a breathtaking underwater landscape. Dr. Chris Yule, a CSIRO geophysicist, unveiled the discovery of ancient dormant underwater volcanoes, previously concealed from human sight. These eight long-dormant volcanoes, some boasting peaks soaring to 1500 meters, stand as silent sentinels of the ocean’s tumultuous past.
These seamounts, formed within the last 20 million years through volcanic activity, harbour crucial insights into ocean dynamics. Dr Helen Phillips, the voyage’s co-chief scientist, highlighted their profound impact on the Antarctic Circumpolar Current, elucidating how these underwater formations create ripples and eddies that significantly influence heat and carbon transport in the ocean depths.
The significance of these discoveries extends beyond scientific curiosity. Dr Phillips emphasised their pivotal role in informing climate policies and planning for the inevitable consequences of rising sea levels. The integration of ship and satellite data promises a comprehensive understanding of ocean circulation, essential in devising strategies to adapt to a changing climate.
In this comprehensive ocean survey, 111 CTD casts were made at 70 stations, diving as deep as 4000 meters and collecting detailed water samples. A towering mooring, akin to 11 Eiffel Towers, continuously monitored salinity, temperature, and currents for 18 months. Mapping efforts unveiled hidden seamounts and deployed various tools, including robotic gliders and Triaxus tows, tracking ocean dynamics. The collected data, involving 13 early-career researchers across a 3500-nautical-mile journey, will significantly advance understanding of the Antarctic Circumpolar Current’s role in Antarctica’s warming, analysed by experts in Australia, the US, and France.
Ultimately, this voyage stands as a testament to human ingenuity and collaboration, shedding light on the formidable power and intricacies of the Southern Ocean. Its revelations pave the way for a deeper comprehension of our planet’s climate system, equipping us to navigate the challenges posed by a rapidly changing world.
As part of the continuous exploration of the world’s oceans, scientists from the NIWA-Nippon Foundation Tonga Eruption Seabed Mapping Project (TESMaP) documented the immediate aftermath of the monumental Hunga Tonga-Hunga Ha’apai eruption in January 2022, marking an international effort among 13 partners including Australia.
Spearheaded by New Zealand’s National Institute of Water and Atmospheric Research (NIWA), the post-eruption scientific expedition captured crucial geological data, video footage, seabed imagery, and water column samples to comprehensively assess the impact of this cataclysmic event.
