By Claire Stremple
KHNS reporter

Reuben Cash wades into Nahku Bay until the water is above his waist. He’s taking samples of ocean water. It’s just starting to snow, but data collection knows no off-season.

“The water has definitely been warmer than the air, but that doesn’t change the fact that it’s cold,” he said. “I also put on an extra pair of long johns.”

Cash is environmental coordinator for the Skagway Traditional Council.

The council is the most recent member of a state-wide tribal network that measures ocean acidification. Samples from Upper Lynn Canal will be part of a regional dataset that helps scientists make a plan for adaption.

He fills a five-gallon bucket and hauls it up the beach, just west of Skagway. Then he takes off his gloves and starts unloading his supplies from a hard case. A mesh net, nitrile gloves, three empty (and sanitized) beer bottles, a baggie of bottle caps, and a small box with a skull and crossbones on it. That’s mercuric chloride.

“They had to send this stuff to me through (Alaska) Seaplanes and so Seaplanes called me up one day and said, ‘We got a box of poison here for Reuben,’” he said with a chuckle.

Cash special-ordered the box of poison because he needs to stop time. Ocean acidification is a process when carbon dioxide from the atmosphere reacts with ocean water to makes it more acidic. That reaction happens constantly — even when the samples are taken out of the ocean. Cash needs mercuric chloride to stop the reaction while he gets his samples to the lab.

He adds several drops of mercuric chloride to the samples, so lab technicians will get a snapshot of what the water was like that day.

“That freezes all the chemistry that’s going on in the water, and then this can get sent to the Sitka lab,” he said.

The data can help scientists understand oceanacidi cation’s effects on subsistence fisheries and marine ecosystems.

Cash and the Skagway Traditional Council are partners with the Southeast Alaska Tribal Ocean Resources (SEATOR) network, a group of tribal organizations that monitor ocean health.

“Some of the work that the tribes are doing here is really kind of pioneering a network,” said Davin Holen, a coordinator for the group.

He works with University of Alaska Fairbanks Alaska Sea Grant program. He said the challenge statewide is that there’s a huge coastline and minimal resources. That’s why everyone is working together.

“This need was seen by our coastal tribes,” Ho-len said. “[It’s] ocean chemistry that’s really impacting subsistence resources.”

He said tribes that have been harvesting shell shand crabs for generations see a change in their subsistence resource. So SEATOR started collecting data in 2016. The goal is to understand what’s happening in the water, so tribes can work with scientists to come up with adaptation strategies.

Back at Nahku Bay, Cash marks the date and exact time in a logbook. He seals the sample bottles and loads them into a cardboard case.

He’ll be back again the next month.