University of Hawaii at Manoa researchers are launching a small fleet of remote-controlled sailing drones that will cruise around the main Hawaiian Islands for the next six months collecting ocean chemistry data.

The effort is part of a $3 million-plus project that aims to measure the impact of climate change on the islands and assess the state’s vulnerability to ocean chemistry changes.

“All we seem to hear about in the news is sea level rise, but there is a lot more going on,” said Christopher Sabine, UH Manoa interim vice provost for research and scholarship and oceanography professor in charge of the project.

Because there is more human-produced carbon dioxide in the atmosphere, more of it is dissolving into the ocean and that’s reducing the seawater pH. This acidification, as it is called, has been shown to impair the ability of coral reefs and shelled organisms to form skeletons and shells.

“There are organisms exposed to pH concentrations not experienced for the last 20 million years. These organisms are going to have to adapt or adjust to the changes, but it is unclear how well they will be able to do that,” Sabine said.

The ocean absorbs most of the heat produced by climate change. The extra heat is not only leading to more episodes of deadly coral bleaching, but is also reducing the flow of the nutrients from below that are essential for ocean productivity.

Hawaii’s marine environment, Sabine said, is more vulnerable to chemical changes because its remote islands sit in the middle of a huge subtropical gyre, where already fewer nutrients rise to the surface.

To measure the ocean chemistry around the islands, Sabine is teaming up with the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Lab and the Cooperative Institute for Climate, Ocean and Ecosystem Studies in Seattle, as well as Saildrone Inc., the manufacturer of the oceangoing drones.

It was 10 years ago that Saildrone accomplished the first “no-handed” Pacific crossing from San Francisco to Oahu.

This week, three 23-foot wind- and solar-powered surface vehicles are scheduled to set sail from Kona after having left from Honolulu Harbor March 21.

The unmanned Saildrone Explorers are equipped with advanced acoustic and security camera systems and loaded with all kinds of sensors that will measure the chemistry of the ocean water nonstop for the next six months.

The drones — each with a 12-foot rigid sail that captures both the wind and the sun in an embedded solar panel — will be operated remotely from Saildrone Inc. headquarters in Alameda, Calif.

Two of the drones will travel in a zigzag pattern around the islands and up to three miles offshore, while the other one circles the island in a relatively straight line.

Sensor-equipped buoys will also be deployed in the waters off Hawaii island, Maui and Kauai, joining four buoys already sitting offshore Oahu.

It will take about a month for the Saildrones to measure the nearshore waters of the Big Island. Working their way up the chain, the surface vehicles are likely to show up in Oahu waters in June.

Those scanning the ocean may see the bright orange sailing vehicles as they do their business 24 hours a day.

“We’re trying to get very close to the islands,” Sabine said.

“We really want to know what chemical changes are where the coral reefs are.”

The data-collection ability of the sailing drones is an oceanographers dream.

“This is a paradigm shift in the ability to get data. I can collect, 1,000 times the data that I would ordinarily collect in the same time,” the researcher said.

Measurements to be taken include temperature, salinity, dissolved oxygen, chlorophyll, turbidity, pH and carbon dioxide, both in the air and in the water.

Sabine said he will be on the lookout for hot spots of ocean acidification. He also will map areas that are safe for organisms that use calcium carbonate to build their skeletons or shells (corals, oysters, crabs, etc.), and areas where the carbon water chemistry is likely to reduce those organisms’ ability to build their bodies.”

The instruments will only monitor atmospheric and ocean properties and not collect any data that can be used to identify people, marine mammals or fish locations.

The largest share of funding for the project will come from last year’s gift to the University of Hawaii of $50 million over seven years, from billionaire Facebook founder Mark Zuckerberg and his wife, Priscilla Chan, for research about the impact of climate change on the ocean.

The largest cash gift in UH history is helping to underwrite research and programs that document changing ocean conditions, explore ways to support healthier ocean ecosystems, enhance coastal resilience from storms and sea-level rise, and study problems for marine creatures.

The Saildrone research is also connected to a NOAA-funded project to assess the vulnerability of the Hawaiian Islands to climate change and ocean acidification.