Project – Time Series Monitoring of Ocean Acidification in Alaska


The Ocean Acidification (OA) monitoring program will continue a nine-year time-series in the Gulf of Alaska along the Seward Line as well as support the deployment of OA moorings adjacent to the oceanographic sampling line.  When combined, these two data streams provide unprecedented resolution to better understand the seasonal dynamics of the carbonate chemistry around Alaska.


Ocean acidification has emerged as a new and potentially high impact issue in Alaska, due to its relatively shallow shelf seas, cold water temperatures and high rates of primary production, which had already led to seasonal manifestations of OA through suppressed carbonate mineral concentrations. Because of Alaska’s remoteness and the high cost of ship time, consortia are forming to maintain support of long-term time-series of physical, biological and chemical oceanographic conditions to understand climate variability and ecosystem change, including funding for equipment replacement.

OA is now recognized as a perennial threat to the global marine environment and recent and ongoing studies have shown that the high latitudes regions of the Gulf of Alaska, the Bering Sea, and the western Arctic Ocean are more susceptible to decreased pH.


AOOS will partner with the Ocean Acidification Research Center (OARC) and NOAA to support the statewide OA research monitoring program, and make data available to the public through the AOOS website.


  1. AOOS will maintain OA sampling of an existing, ongoing oceanographic time-series transect (Seward Line) in the northern Gulf of Alaska two times per year to quantify the physical and biogeochemical controls on OA.  Each year, the OARC will conduct two oceanographic cruises along the Seward Line and make measurements of ocean acidification as well as the associated carbon biogeochemistry of the region.  During each bi-annual (May and September), 450 samples will be collected for dissolved inorganic carbon (DIC), total alkalinity (TA), partial pressure of CO2 gas in the water (pCO2),  pH, carbonate mineral saturation states (Ω), oxygen isotopes (δO18), dissolved oxygen (DO), and nutrients.  This will fund the completion of ten years of monitoring on the Seward Line, the minimum amount of time necessary to capture definitive changes in ocean carbonate chemistry. OA data will be combined with observations of specific pelagic and benthic calcifying organisms to monitor how keystone species in the food web are responding to increased intrusion of atmospheric CO2.
  2. AOOS will contribute $15,000 as part of a consortium to maintain an OA buoy network ($45k annually needed) that will make continuous measurements of pCO2, pH, temperature, salinity, DO, and florescence at the surface and near the bottom.   AOOS will contribute funding to a consortium to support maintenance of existing OA sensors on moorings in the Bering Sea and the Gulf of Alaska. Previous AOOS funds were used to add additional OA sensors to a mooring in the Chukchi Sea, funded through NSF, which enabled it to collect OA data year-round.  Data from all moorings, as well as along the Seward Line, will be made available on the AOOS website under an agreement to be established between Mathis and AOOS.

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