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Kachemak Bay appears to be a refuge from ocean acidity levels that prevent shellfish and marine creatures from growing skeletons and shells.
That’s based on first results of a study started in 2017 that placed an array of sensors nearshore.
Researchers found that Kachemak Bay also is one of the most variable places on earth in terms of hourly acidic changes. That’s likely due to its vast tidal range, says researcher Cale Miller.
“I think it’s the second largest in the world being about eight meters, or 24 feet in total, in June and December. The other thing that’s important is just the oceanography of the Bay itself. Because you get a lot of influx from the Gulf of Alaska and Cook Inlet and the Homer Spit bisects the Bay into two distinct regions that have different oceanographic patterns. There’s probably evidence that the different organisms, especially the photosynthesizing organisms, are different between the inner and outer portions of the Bay. And those are what you would call that foundational, or the lower trophic level or food chain items, for a lot of other organisms that they live on.”
Miller, of the University of California, worked under the guidance of Amanda Kelly, an assistant professor at the University of Alaska at Fairbanks.
She says the multi-year study will give the Bay’s many shellfish farmers a better gauge of corrosive water conditions, and when.
“I think one of the benefits to doing studies like these is that we’re able to identify areas that are potentially good for shellfish or maybe not so good, or maybe better for seaweed aquaculture. It allows for mitigation planning and adaptations, community adaptation planning. Let’s say shift focus from one species to another is an example of mitigation, or maybe a change in the time of year that fisheries are open to better fit with these changing conditions. They need to be able to better strategize for their long term future.”
Research so far shows that Southwest and Southeast Alaska are at higher risk for ocean acidity and Juneau is identified as a hot spot.
Kelly says that region is already on their research radar, as are other Alaska regions.
“ I got an Alaska Sea Grant Award to do a comparison of Kachemak Bay versus Juneau. And I have these pH sensors down in Juneau and that’s part of our next step in terms of looking at other areas regionally. So that’s certainly exciting.”
In other good news: This fall the state ferry Columbia will begin testing the waters for acidity again, a project that began in 2017 but was derailed last year due to the pandemic. The ferry runs from Southeast Alaska across British Columbia to Bellingham, Washington. It is part of an unprecedented Alaska/Canada project to learn how increasing ocean acidity affects regional fisheries.
The Columbia ferry data will be uploaded daily to the Alaska Ocean Acidification Network website.
Laine Welch, Alaska Fish Radio, 27 May 2021. Text and audio.
