Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

« Back to Publications search

Sea surface aragonite saturation state variations and control mechanisms at the Gray’s Reef time-series site off Georgia, USA (2006–2007)

  • Author(s): Liang Xue, Wei-Jun Cai, Adrienne J. Sutton, Christopher Sabine
  • Marine Chemistry
  • October 20, 2017
Citation: Xue, L., Cai, W. J., Sutton, A. J., & Sabine, C. (2017). Sea surface aragonite saturation state variations and control mechanisms at the Gray’s Reef time-series site off Georgia, USA (2006-2007). Marine Chemistry, 195, 27-40. https://doi.org/10.1016/j.marchem.2017.05.009

We report an annual cycle of surface seawater aragonite mineral saturation state (Ωarag) during 2006–2007 at the Gray’s Reef time-series site off Georgia, USA, calculated based on three-hourly observations of carbon dioxide partial pressure (pCO2) and salinity-derived total alkalinity. Ωarag varied between 2.30 and 4.39 with low values (< 3.00) mainly during February–April 2007 and high values (> 3.50) during July–October 2006 and July–September 2007 as well as during two biological production spikes (April–June 2007). We first present a qualitative analysis of the drivers of Ωarag variability based on property regressions with surface temperature, salinity and apparent oxygen utilization, and then quantify the contributions of temperature, air-sea exchange, mixing, and biological processes to monthly Ωarag net changes using a simple 1-D mass budget model. Our analyses suggest that river inputs played the most important role in the seasonal variation of surface Ωarag, in contrast to temperature control on pCO2. Nevertheless, the primary processes controlling monthly Ωarag net change varied with time of year. Furthermore, river inputs lowered Ωarag by 0.28 and 0.48 in July–August and September–October 2007 relative to the equivalent periods of 2006. This implies that interannual Ωarag variability at this location may be greater than that due to the influence of increased atmospheric CO2 over the past few decades, making efforts to discern decadal coastal ocean acidification trends particularly challenging. In addition, although sea surface salinity varies substantially in coastal waters, our analysis suggests that similar to the open ocean Ωarag is essentially determined by carbonate ion concentration ([CO32 −]), not calcium ion concentration ([Ca2 +]) or the stoichiometric solubility product (K′sp), both varying substantially with salinity. Finally, we show that the difference between total alkalinity (TA) and dissolved inorganic carbon (DIC) is a better proxy for [CO32 −] and Ωarag compared with the ratio (TA/DIC) and helps to better elucidate processes affecting Ωarag in coastal oceans.

View Article

Effects of ocean acidification and temperature on Alaskan crabs

Red King Crab
Image credit: David Csepp, NMFS AKFSC ABL

Long-term declines of red king crab in Bristol Bay, Alaska may be partially attributed to ocean acidification conditions. These impacts may be partially responsible for the fishery closures during the 2021–2022 and 2022–2023 seasons. Researchers found that ocean acidification negatively impacts Alaskan crabs generally by changing physiological processes, decreasing growth, increasing death rates and reducing shell thickness. Funded by the Ocean Acidification Program, scientists at the Alaska Fisheries Science Center continue to investigate the responses of early life history stages and study the potential of various Alaska crabs to acclimate to changing conditions. Results will inform models that will use the parameters studied to predict the effects of future ocean acidification on the populations of red king crab in Bristol Bay as well as on the fisheries that depend on them. Fishery managers will better be able to anticipate and manage stocks if changing ocean chemistry affects stock productivity and thus the maximum sustainable yield.

More about this work

Forecasts for Alaska Fisheries

Crab pots and fishing nets in Alaska's Dutch Harbor
Image credit: Michael Theberge

Understanding seasonal changes in ocean acidification in Alaskan waters and the potential impacts to the multi-billion-dollar fishery sector is a main priority. Through work funded by NOAA’s Ocean Acidification Program, the Pacific Marine Environmental Laboratory developed a model capable of depicting past ocean chemistry conditions for the Bering Sea and is now testing the ability of this model to forecast future conditions. This model is being used to develop an ocean acidification indicator provided to fisheries managers in the annual NOAA Eastern Bering Sea Ecosystem Status Report.

ADAPTING TO OCEAN ACIDIFICATION

The NOAA Ocean Acidification Program (OAP) works to prepare society to adapt to the consequences of ocean acidification and conserve marine ecosystems as acidification occurs. Learn more about the human connections and adaptation strategies from these efforts.

Adaptation approaches fostered by the OAP include:

FORECASTING

Using models and research to understand the sensitivity of organisms and ecosystems to ocean acidification to make predictions about the future, allowing communities and industries to prepare

Closeup of oysters cupped in someone's hands

MANAGEMENT

Using these models and predictions as tools to facilitate management strategies that will protect marine resources and communities from future changes

TECHNOLOGY DEVELOPMENT

Developing innovative tools to help monitor ocean acidification and mitigate changing ocean chemistry locally

REDUCING OUR CARBON FOOTPRINT

50 more ways to reduce your carbon footprint >

On the Road

Drive fuel-efficient vehicles or choose public transportation. Choose your bike or walk! Don't sit idle for more than 30 seconds. Keep your tires properly inflated.

With your Food Choices

Eat local- this helps cut down on production and transport! Reduce your meat and dairy. Compost to avoid food waste ending up in the landfill

With your Food Choices

Make energy-efficient choices for your appliances and lighting. Heat and cool efficiently! Change your air filters and program your thermostat, seal and insulate your home, and support clean energy sources

By Reducing Coastal Acidification

Reduce your use of fertilizers, Improve sewage treatment and run off, and Protect and restore coastal habitats

TAKE ACTION WITH YOUR COMMUNITY

You've taken the first step to learn more about ocean acidification - why not spread this knowledge to your community?

Every community has their unique culture, economy and ecology and what’s at stake from ocean acidification may be different depending on where you live.  As a community member, you can take a larger role in educating the public about ocean acidification. Creating awareness is the first step to taking action.  As communities gain traction, neighboring regions that share marine resources can build larger coalitions to address ocean acidification.  Here are some ideas to get started:

  1. Work with informal educators, such as aquarium outreach programs and local non-profits, to teach the public about ocean acidification. Visit our Education & Outreach page to find the newest tools!
  2. Participate in habitat restoration efforts to restore habitats that help mitigate the effects of coastal acidification
  3. Facilitate conversations with local businesses that might be affected by ocean acidification, building a plan for the future.
  4. Partner with local community efforts to mitigate the driver behind ocean acidification  – excess CO2 – such as community supported agriculture, bike & car shares and other public transportation options.
  5. Contact your regional Coastal Acidification Network (CAN) to learn how OA is affecting your region and more ideas about how you can get involved in your community
       More for Taking Community Action