Ocean Acidification

Ocean acidification (OA) is global problem that is most often studied in open ocean environments, while the social and economic impacts are most often concentrated nearshore. The ocean is 30% more acidic today than it was 300 years ago, traceable to the increasing levels of atmospheric carbon dioxide (CO2). When CO2 is generated and released, it concentrates in the atmosphere. The ocean acts as a carbon sink and absorbs the CO2 in the atmosphere. The ocean is naturally slightly basic. However, with additional CO2 in the water, carbonic acid forms, which can lower the pH, making the ocean more acidic. More acidic water—lower pH-- affects shell building organisms because they require a higher pH to form their shells. With a lower pH environment, shell-building marine organisms experience more stress and have to expend more energy to form their shells. Changes in ocean chemistry occur seasonally, and different regions are vulnerable to OA for different reasons and at different times throughout the year.

This water quality monitoring program stemmed from the collective concerns expressed by Kodiak Tribes that the wild foods they depend upon for spiritual and nutritional sustenance may acquire contaminants from the archipelago’s terrestrial and marine waters. This project is funded through EPA IGAP and National Oceanic and Atmospheric Administration (NOAA). Samples are being collected in Port Lions, Ouzinkie, Old Harbor, Larsen Bay and South Trident Basin, Kodiak.

The project focuses on the baseline data collection of ocean waters adjacent to each community. Sites are sampled weekly for temperature, salinity, conductivity and dissolved oxygen. Results are used to build an understanding of current local OA conditions, seasonal changes, and the impacts on their environment. A consistent time series, will help communities better understand the current water chemistry in areas that are important for harvesting shellfish and other subsistence resources.

Two types of water samples are being collected. In Kodiak, ocean water is pumped into the NOAA facility at South Trident Basin where continuous pCO2, temperature, and salinity data are collected using a Burke-o-Lator (BoL). This type of sample is referred to as continuous data. The BoL can measure the concentration of the mineral aragonite, a mineral that is critical to shell formation, total carbon from non-organic sources, and the amount of carbon dioxide gas that is dissolved in seawater. The BoL can also measure samples collected from different locations, which are called discrete samples.

Discrete sampling is mostly conducted by the designated Tribal Environmental Coordinator in each community. All samplers on Kodiak Island use instruments (YSI and Niskin) to collect surface and subsurface samples. Samplers are trained in the protocols during an annual Marine Water Quality Workshop in Kodiak, Alaska. The NOAA lab in Kodiak ships out collection materials to the villages and processes all samples.

The marine environment is critical to the existence of the Native communities in south-west Alaska. Understanding the basic environmental parameters and how OA is affecting each community is critical in developing an understanding for long-term sustainable environmental programs and coastal resilience.

This is part of a larger state wide effort, for more information check out the websites listed below or contact:  Andie Wall- KANA Environmental Coordinator at 907.486.1313 or Andie.wall@kodiakhealthcare.org

For more information, visit:
https://aoos.org/alaska-ocean-acidification-network/
http://www.seator.org/ocean-acidification
https://oceanservice.noaa.gov/facts/acidification.html