Over six years, UAF's International Arctic Research Center (IARC) and private-sector collaborators developed a way to integrate a carbon dioxide sensor into an unmanned underwater vehicle, the Seaglider. The modified device transmits high-resolution data via satellite for extended periods, providing a continuous view of ocean chemistry. This innovation required significant adaptation to the Seaglider's design.
Industry partners Advanced Offshore Operations and 4H JENA Engineering modified the Contros HydroC sensor to be lighter and more compact, making it suitable for the Seaglider. However, its larger size and higher power demand required adjustments to the Seaglider's buoyancy, achieved through 3D-printed components and weight recalibration.
"Monitoring carbon dioxide levels in the ocean creates the information needed to develop climate change adaptation plans," explained Claudine Hauri, an oceanographer and IARC deputy director.
Carbon dioxide, a major greenhouse gas released from burning fossil fuels, contributes to global warming. Oceans absorb roughly one-third of these emissions, mitigating atmospheric effects but causing acidification.
"When carbon dioxide dissolves in the ocean, it decreases the pH, leading to ocean acidification," Hauri said. "These conditions make it difficult for some marine organisms to build and maintain their shells and can even affect fish."
Encouraged by their success with carbon dioxide sensors, the team has started integrating a methane sensor into the Seaglider, now undergoing testing. Methane, while shorter-lived than carbon dioxide, has a greater heat-trapping capacity. Human activities, such as agriculture and fossil fuel extraction, account for 60% of methane emissions, while natural sources include oceanic methane seeps.
Frozen methane hydrates in subsea permafrost and ocean sediments are destabilized by warming waters, releasing methane. This process can lead to additional ocean acidification as microorganisms convert methane to carbon dioxide.
The team also aims to address operational challenges in Alaska's harsh waters.
"The Seaglider we're using isn't really made for Alaska's coastal oceans," Hauri said. "We're looking for an autonomous underwater vehicle that can withstand the elements. Then we'll integrate it with the carbon dioxide and methane sensors to collect data from some of the most remote spots on Earth, furthering our understanding of chemical processes in the ocean."
Research Report:Expanding seawater carbon dioxide and methane measuring capabilities with a Seaglider