Featured Story - Ocean pH Falling Faster Than Previously Predicted

With all the talk of climate change in the atmosphere, few realize that the increased carbon dioxide levels (a key greenhouse gas) are largely stored in the ocean where, aside from changing our climate, they have direct effects on ocean chemistry. The SeaKeeper 1000™ monitoring system is an important technology to precisely and economically monitor these changes.

Acidity is expressed in terms of its pH value. A lower pH number means more acid. The Fall 2006 issue of the SeaKeepers Report featured an article about the acidification of the ocean. Many experts believe that that ocean acidification could be the most profound environmental impact on the planet this century, and could lead to levels not seen on Earth in the last 10 million years.

These pictures show the range of damage associated with higher temperatures and higher concentrations of dissolved carbon dioxide (CO2). More dissolved CO2 produces a lower pH reading. The SeaKeeper 1000™ can measure precise changes in oceanic conditions and provides a cost-effective way to monitor climate change. Image credit: Coral Reef Targeted Research and Capacity Building for Management Program

In the last century the pH level of the ocean dropped 0.1 units, with the current global average at approximately 8.1 units. Globally, existing models show up to a 0.4 unit decrease this century as a result of the increased levels of carbon dioxide (CO2). According to new analysis by the US National Oceanic and Atmospheric Administration (NOAA), Caribbean researchers are now looking at a drop in pH on the order of 0.1 units per decade. This is an extreme, potentially catastrophic change, particularly in the ocean food chain. Should pH levels fall this much, by mid-century coral will die, crabs, lobsters and shellfish will no longer be able grow new shells and plankton – the very base of the food chain – will not be able to reproduce. Another new NOAA survey along the west coast of the U.S. also shows rapidly accelerating rates of pH drop. The survey, completed this Spring, shows areas of extremely high acidity as close as five miles off the U.S. northwest coast, much closer than previously witnessed, and close enough to begin raising fears of negative impacts on inshore fish stocks and wildlife.

This image shows the change in sea surface pH during the last two centuries, with the average approximating nearly a tenth of a unit decrease in pH. LOWER pH values indicate MORE acidity. Recent data shows a huge acceleration in acidification. Prediction models show a further loss of 0/4 units by the end of this century.
The Seakeeper 1000i is one of very few automated systems with the capability to monitor
pH to an accuracy of two decimal places.

The effect of greenhouse gases on ocean acidification is so new that just five years ago many scientists did not even see the need to measure the pH of the ocean. They thought it was that stable. Now, dozens of systems are being deployed to precisely track pH—something that the SeaKeeper monitoring network has been doing for eight years. The SeaKeeper 1000TM is capable of measuring pH down to two decimal places. SeaKeepers is presently working with developers on a new sensor that could yield pH accuracy of three decimal places and withstand longer intervals between calibrations. Other sensors are being developed that can measure the dissolved carbon dioxide (CO2)—the substance that is causing ocean acidification. Development costs for these next-generation sensors can be upwards of US $100,000. If interested in funding all or a portion of these new instruments please contact CEO John Englander at englander@seakeepers.org.