Nathalie Zilberman (UCSD) and Charlie Branham (Seabird Scientific) on board NIWA's RV Tangaroa working on the CTD, an instrument used to calibrate sensors for argo floats. Photo: UCSD / Steven Diggs
Scientists have returned from a two-week research expedition in the south-west Pacific Ocean, where autonomous robots have been deployed to send data about deep-sea climate trends.
Researchers from the National Institute of Water and Atmospheric Research (NIWA) and Scripps Institution of Oceanography sent four robots, known as Deep Argo floats, along the Kermadec Trench.
They collect information on the ocean temperature, salinity and water flow to a depth of 6000 metres.
The floats surface every 10 days to send data back via satellite and are left to work autonomously for up to six years.
NIWA physical oceanographer Dr Denise Fernandez said the floats would give scientists clues to long-term deep-sea trends.
"The ocean depths are crucial to the world's climate and ecosystems - they act as 'carbon sinks', store heat, and transport things like oxygen and nutrients around the globe via currents," she said.
"However, only 10 percent of ocean data comes from below 2000m, so we know very little about how significant the role of the deep ocean is at regulating the climate system.
"These floats will provide much needed information about what's happening way below the surface."
NIWA physical oceanographers Drs Denise Fernandez and Phil Sutton on board RV Tangaroa and Dave Murphy (Sea-Bird Scientific) on the far left. Photo: UCSD /Mitchell Chandler
New Zealand's environment was greatly affected by deep-ocean processes, with warm subtropical currents coming from Australia and the cold Antarctic circumpolar current coming from the south, Fernandez said.
"The deep ocean isn't immune to climate change. The tropics are getting warmer and ocean currents are carrying this heat towards us, driving the consistent marine heatwaves that New Zealand has experienced over the past few years," she said.
"By understanding the deep ocean, we understand our entire climate and environment better."
NIWA said the work was part of the larger Argo Program, a global network of nearly 4000 autonomous robotic floats.
The institute has deployed around 2000 Argo floats in the Pacific, Indian and Southern Ocean over many voyages since 2004.
As part of the most recent expedition, Fernandez led a STEM activity for 7-year-old students from Silverstream School in Upper Hutt.
The students decorated Styrofoam cups that were attached to an instrument and lowered to a depth of 6000m to study the effect of water pressure.
