Oceanographers share expedition highlights, ship tour with UH Hilo

Recently, SOEST oceanographers offered UH Hilo students tours of the research vessel Roger Revelle in Hilo and shared highlights from an ongoing 67-day expedition from Alaska to Tahiti.

Mariko Hatta, affiliate graduate faculty in the SOEST Department of Oceanography and one of the principal investigators on the expedition; UH Mānoa oceanography graduate student Gabrielle Weiss; and others led the tours and presentations during a three-day stop in Hilo.

The current expedition is part of GEOTRACES, a global collaboration of oceanographers seeking to better understand ocean chemistry.

GEOTRACES measures trace elements—which can be nutrients or contaminants from human activity—and isotopes—which can be used to track ocean processes—to understand how the ocean and Earth work. Where these chemicals go and how long they take to get there helps determine how many fish the oceans can support and can even slow or accelerate climate change.

The UH Hilo students saw a working research vessel midway through a more than 5,000 mile journey. The students toured key scientific instruments on board, descended into the belly of the Roger Revelle’s engine room and got a taste of what life is like at sea.

Hatta and Weiss’s role in this project is to measure aluminum, iron and manganese in the Pacific. Iron is a vital marine nutrient and understanding its distribution and cycling in the Pacific is one of GEOTRACES major research goals.

In the ocean, iron can be the difference between a saltwater desert and a feeding bonanza complete with whales, fish and seabirds. On the global scale, the presence or absence of these rare nutrients limits how much life the oceans can support and helps determine where it is found.

“The presence or absence of iron is what decides how productive the ocean is for much of the North Pacific. Our measurements will help figure out where the North Pacific’s iron comes from and how it might change in the future,” said Hatta.

This expedition’s data may provide guidance for a new industry with potential for dire environmental impacts: deep sea mining. In international waters southeast of the Big Island, an area called the Clarion-Clipperton Fracture Zone has attracted the interest of more than 15 countries hoping to extract minerals from the seafloor. Mining the deep sea would destroy fragile and mysterious ecosystems, and could send toxins stored in deep sea mud into the upper reaches of the ocean and, eventually, the world’s seafood.

This GEOTRACES expedition is perfectly positioned to take a chemical snapshot of these waters, where leases have been granted for seabed mining of manganese deposits, before any underwater excavation begins. A clear baseline will ensure that the environmental impacts of deep sea mining can be laid bare.

Hatta and Weiss plan to go back to Hilo next year to share additional data and the project summary with the UH Hilo community and local schools.
Follow the expedition on Twitter (@followgp15), Facebook (facebook.com/followgp15) and Instagram (geotraces_gp15).