Coral reefs that are acclimatized to pH levels at three cool and shallow volcano carbon dioxide seeps in Papua New Guinea as pH declines from 8.1 to 7.8 (the change expected if atmospheric carbon dioxide concentrations increase from 390 to 750 ppm).  Imagescourtesy of Katharina Fabricius.[x]

Ocean acidification (OA) is a global change in ocean chemistry resulting from the ocean’s uptake of carbon dioxide (CO₂) which is increasing in the atmosphere due to the burning of fossil fuels, land use change, and cement production.[i]  Increased levels of CO₂ cause an increase in acidity (or decrease in pH) and an array of other chemical changes in the carbonate system of the ocean that can affect a variety of organisms, particularly those with calcium carbonate shells or skeletons (i.e. corals, shellfish, plankton).[ii]^{,[iii],[iv][v]}  However, recent studies have shown the physiology of non-calcifying species such as fish, seagrass and harmful algal species are affected by these changes as well.[vi]^{,[vii],[viii]}  Additionally, changes in other environmental factors (i.e. temperature) and coastal influences such as nutrient run-off, freshwater input, acidifying gases (NO_x & SO_x), sedimentation and geology can affect the buffering capacity of coastal waters causing impacts to vary on smaller spatial scales.[ix]

Understanding the impacts of acidification on local and regional scales presents a  challenge due to the complex physical and biogeochemical interactions.[xi]  Determining the spatial and temporal resolution of measurements needed to establish an accurate baseline and monitor changes in water chemistry would allow for identification of OA “hot spots” and refugia in the Southeast.[xii]  In addition, prioritization of and best practices for measured parameters are needed to answer these questions.[xiii]  The first in depth observing study of the waters along the Southeast US suggests that within this region the Mid-Atlantic Bight shelf waters are least saturated with respect to a carbonate mineral, aragonite (?_A<2).[xiv]  Identification of potentially impacted ecologically and economically important species in the region such as coral reefs, shellfish fisheries and harmful algal blooms coupled with in-situ habitat monitoring or laboratory experiments will allow identification of potential biological impacts.  With this data in hand ecosystem and socio-economic models should also be developed to understand the broader impacts of OA in the Southeast so we can better adapt to changes in ocean chemistry and marine ecosystems.

Additional Resources:

·         NOAA Ocean Acidification Program: general ocean acidification info, coral reef monitoring information, OA publications, educational resources oceanacidification.noaa.gov

·         NOAA Pacific Marine Environmental Laboratory: access information monitoring platforms  and corresponding data http://www.pmel.noaa.gov/co2/story/Ocean+Acidification

Please request additional information at or direct questions to:

noaa.oceanacidification@noaa.gov