Columbia collecting seawater data for acidification study

One of the state's public ferries will help collect data on ocean acidification during its regular route.

The news was announced last week by Alaska Coastal Rainforest Center at University of Alaska Southeast, which has partnered with the Alaska Marine Highway System, British Columbia's Hakai Institute, Alaska Ocean Observing System and other federal agencies on the project.

The vessel chosen for the data collection study is the M/V Columbia, which at 418 feet and a gross tonnage of 3,946 is the ferry system's largest. On its route between Bellingham, Washington and Southeast Alaska, a seawater monitoring system affixed to its hull will measure seawater for temperature, dissolved oxygen content, salinity and its carbon dioxide levels. Once read, sensors link with onshore observatory stations connected through the Alaska Ocean Acidification Network and other researchers.

These variables will help coastal researchers in the United States and Canada keep tabs on ocean acidification, a process driven by CO2 absorption by seawater. As the greenhouse gas is discharged by human activity into the atmosphere, roughly a quarter – or 7,000,000 tons each day – is sequestered in the planet's oceans. The increased CO2 content reacts with seawater to create carbonic acid, which in turn affects overall acidity.

This can be problematic for marine life, particularly shellfish. Increased acidity can make it harder for larvae to form shells quickly enough to survive into adulthood, and can cause added stress for those which do. This can have negative impacts on commercial, sport and subsistence fisheries, and shellfish farms in Oregon, Washington and British Columbia have already begun seeing the effects with declining seed production.

Getting a good read on the variables can be difficult, but the research partners explained the Alaskan ferry fits the bill quite well. Operating 11 months each year, it covers a round-trip route of 1,854 miles each week. As it travels the same route every week, the Columbia's monitoring system can continuously track these different indicators, how they vary from one place to the next and by season. From this, researchers hope to be able to determine what is driving the acidification process.

"There's no manipulation of the seawater, these are all direct measurements that don't involve changes in the seawater character in any way," said Wiley Evans, an oceanographer with the Hakai Institute. "Ocean acidification is a moving target. It's the trajectory of our coastal waters being forced by increasing atmospheric CO2 content, and in order to capture that we need to make measurements over a long period of time."

The Columbia's route between Skagway and Bellingham is the continent's longest ferry run, and its 11-month schedule will allow for a nearly complete data set. It also runs during the yearly spring bloom, which can shed some light on how ocean acidification affects phytoplankton and other marine life.

The monitoring system was designed by the National Oceanographic and Atmospheric Administration, which has been collecting acidification data in the open ocean since 2000. NOAA researcher Geoff Lebon explained that the Columbia collection will be unique in that it will include seasonal changes, ocean currents, high rainfall, river inputs and glacial melt along an extended stretch of coastline. The study will likely endure for years, with the data being used alongside other sources.

"The data will be available, probably not for another year or so," explained Allison Bidlack, ACRC director.

This particular project began collecting data two weeks ago, with the monitor installed last spring during Columbia's last layup. A website set up through AOOS will likely put the information out to the public, potentially before Fall 2018.