Alaskan Ocean Acidification Network- scientist interview: Kris Holderied

Kris Holderied is a physical oceanographer and the director of NOAA’s Kasitsna Bay Lab in Kachemak Bay. Kris has been an active contributor to ocean acidification nearshore monitoring and recently joined the Alaska OA Network’s executive committee.

Q: Why is Kachemak Bay is a particularly interesting place to study ocean acidification?
Well, to start with, Kachemak Bay is one of the most fantastic places to study Alaska coastal ecosystems – it’s a great natural laboratory, with rich marine fish, mammal and bird communities and all the marine habitats found across the Gulf of Alaska, including kelp forests, seagrass beds, mudflats, salt marshes and rocky intertidal areas that emerge during our huge low tides. It also has many different types of sub-estuaries, from wide, shallow flats to deep, narrow fjords and rivers with a range of glacial water input.  All in a place that, for Alaska, is easy to access and where we can work year round out of our NOAA Kasitsna Bay Lab. For OA it’s also a particularly interesting place to study nearshore waters, because of variety of physical conditions that can change water chemistry in the bay – including freshwater from glacial and non-glacial watersheds and upwelled ocean waters coming in from the nearby entrance to Cook Inlet. But rich primary production in the bay, whether from phytoplankton in the water and kelp and seagrass along the shore, also means it is a place where biology can affect water chemistry and OA conditions.

Kachemak Bay at low tide. Photo: ShoreZone Alaska

Q: Do the conditions you’re finding in Kachemak Bay follow similar patterns to other parts of Alaska?
One of the things we found out right away, even with the relatively simple pH sensors that have been in place in Kachemak Bay since the early 2000s, is how much variability there is in OA conditions in the bay, both seasonally and on really short time scales. That’s now been measured much more accurately with continuous observations from sensors deployed in the bay by Amanda Kelley from UAF. The high variability we see in the bay has also been found in other coastal areas around the state where more frequent observations are being made.

This photo shows the experimental OA system at the Kasitsna Bay Lab. Pictured are animal culture containers during a 2-way experiment (temperature and OA) on the black chiton. Photo: Amanda Kelley.

Q: Tell us a little more about the type of ocean acidification monitoring and research going on in the bay and the main questions you and other partners are trying to answer.
Most of our work in Kachemak Bay has been focused on quantifying variability in OA conditions in estuary waters, with a goal to better understand what drives those changes and provide information that helps determine what species might be vulnerable to those conditions. Getting a handle on how much and how fast water chemistry changes, from daily to multi-year time scales, is also needed to determine how well we can detect long-term trends in OA conditions. We partner with other researchers for all our OA work. On our monthly oceanography surveys, we collect water samples which are analyzed at the Alutiiq Pride lab in Seward.  Amanda Kelley has sensors deployed for continuous measurements at five sites around the bay and she has also set up an OA experimental testing system at our lab which can be used to investigate species responses to different OA conditions.

Q: Can you tell us about a particularly memorable moment in the field or in the lab?
One of my most memorable field experiences is from far south of here, in the Northwestern Hawaiian Islands. We were snorkeling at multiple islands to collect field data to validate coral reef habitat maps were making from satellite data.  At one site we jumped into the water from our small boat and were immediately dragged with a strong current towards a shallow break in the reef.  Swimming as hard as we could, we barely got back to the boat.  Repositioning away from that current and getting in the water again, we looked back at gap … only to see a Hawaiian monk seal right in the middle of the current, holding position with little apparent effort and seemingly quizzical about our struggles.

Q: You’ve mentored students in the past including NOAA Hollings Undergraduate Scholars.  What advice would you give to a student interested in getting into the field of ocean acidification?
I think understanding how different species respond to the intersecting effects of OA, climate change and other stressors, like harmful algal blooms or pathogens, is really interesting. And knowing what species are vulnerable to these effects and when they might be vulnerable is important for fishermen, oyster farmers and other people who make a living from the ocean. These questions cross different areas of science, so I’d encourage students to take a cross-disciplinary approach to their studies and also get grounded in ecological relationships and ecosystem dynamics.

Alaskan Ocean Acidification Network, 26 March 2021. Article.

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