Oceanographic assessment of the outer coastal region between Wrangell-St. Elias and Glacier Bay National Parks and Preserves

Pete Shipton, University of Alaska Fairbanks-College of Fisheries and Ocean Sciences, deploys CTD (measuring conductivity, temperature, and depth) along the outer coast of Glacier Bay National Park and Preserve as part of the Southeast Alaska Network oceanographic monitoring.

The outer coastal region between Wrangell-St. Elias National Park and Preserve and Glacier Bay National Park and Preserve located in southeast Alaska consists of over 300 miles of coastline. The region is home to the largest tidewater and piedmont glaciers in North America, recently deglaciated tidewater fjords, globally significant salmon runs, and marine bird and mammal populations. However, the ecosystem structure and controlling processes are not well known in this pristine region that is currently experiencing rapid ecological change. The National Park Service (NPS) and the University of Alaska Fairbanks (UAF) College of Fisheries and Ocean Studies initiated an oceanographic monitoring program in this region during 2022.

The research team from UAF and NPS conducted sampling during June 2022 in fjord and nearshore regions including Icy Bay, Yakutat Bay, Disenchantment Bay, and Lituya Bay. They collected data on a number of oceanographic parameters, including water column profiles of conductivity, temperature, depth, macronutrients, dissolved inorganic carbon, total alkalinity, chlorophyll-a, and zooplankton.

Preliminary summary from the June 2022 mission::

• Tidewater glaciers are highly influential in structuring the coastal and fjord marine ecosystems within Southeast Alaska.
• Bottom topography (i.e., sill structure) plays a pivotal role in controlling fjord dynamics and the degree of exchange between fjords and nearshore oceanic environments.
• Waters at or nearing corrosive conditions (Ω_Ar and Ω_Ca) is a results of low-total alkalinity glacial runoff. Undersaturated conditions occur seasonally in Southeast Alaska and can indicate stressful environmental conditions for calcifying organisms during summer months when glacial discharge is high.

For more information, check out this poster describing the study and results.