Ocean Acidification

It's not just the temperature change...

Ocean Acidification Experimentation

Can an increase in dissolved CO₂ change the pH of seawater? With your lab group or partner, choose one of the following hypotheses:

Increased CO₂ will cause the pH to become more acidic
Increased CO₂ will cause the pH to become less acidic and instead, become more basic (alkaline).
Increased CO₂ will have no effect on pH at all.

To test your hypothesis, you will use a chemical called bromothymol blue (BTB). This chemical is commonly used in many laboratory experiments to test for a change in pH. You will add CO₂ to plain tap water. The source of CO₂ you will use in this experiment will be the CO₂ that you exhale.

Materials:

Test tube, flask, or similar size clear glass
Drinking straw
10 ml of Bromothymol Blue (BTB) in solution
A source of CO₂— you!

Procedure:

Pour 10 ml of BTB solution into the test tube. Make note of its color.
Exhale your CO₂ through the straw into the test tube. Make sure you don't "suck up" any of the BTB solution into your straw and mouth.
When a color change has occurred, stop exhaling CO₂ into the straw. Compare your color change to the image below.

Discussion:

Describe the results of your CO₂/pH experiment.

Which hypothesis is supported by the results? Explain why.

Your experiment was a small scale experiment completed at a lab bench. Can the results of this experiment be extrapolated to understanding the effect of increased CO₂ on pH in the oceans? Explain why or why not?

Acidic, Neutral, Basic

Oyster farmers have been on the front lines of ocean acidification. In Washington and Oregon, oysters farms are in coastal Pacific waters where upwelling currents are bringing up cold, deep water with higher amounts of CO₂ and a more acidic pH. Watch and listen to two oyster farmers from Taylor Shellfish Farms in Washington state talk how about ocean acidification is impacting their young oysters.

Inside the UAE shellfish farm that is growing millions of oysters Dibba Bay Oysters grows millions of shellfish in the nutrient-rich waters of the Sea of Oman

Multiple Stressors and Ecological Complexity Require a New Approach to Coral Reef ResearchOcean acidification, climate change, and other environmental stressors threaten coral reef ecosystems and the people who depend upon them. New science reveals that these multiple stressors interact and may affect a multitude of physiological and ecological processes in complex ways. The interaction of multiple stressors and ecological complexity may mean that the negative effects on coral reef ecosystems will happen sooner and be more severe than previously thought. Yet, most research on the effects of global change on coral reefs focus on one or few stressors, pathways or outcomes (e.g., bleaching). Based on a critical review of the literature, we call for a regionally targeted strategy of mesocosm-level research that addresses this complexity and provides more realistic projections about coral reef impacts in the face of global environmental change. We believe similar approaches are needed for other ecosystems that face global environmental change.

FIGURE 1. (A) A conceptual framework describing ecological processes that contribute to coral reef growth and maintenance vs. the biological and anthropogenic factors that can work against these processes. The inner circle depicts important coral reef ecosystem constituent species. The next circle represents ecosystem features that are important to people. The next circle, along with the arrows showing calcification and decalcification illustrates that in pre-Anthropocene times coral reefs experienced net growth where calcification probably exceeded decalcification; the balance has been reversed at some time during the Anthropocene. The outermost circle captures key environmental stressors that affect coral reef health and determine whether coral reefs grow or decline. Panel (B) demonstrates how increased ecological sensitivity due to multiple stressors (blue line) can lower the threshold at which sea surface temperature causes harm to coral reefs and thus hastens the onset of damages. Panel (C) shows the dimensions along which new science must be expanded, and how, in order to provide more policy relevant science (inspired by Cinner et al., 2015).

7A: C02 and Ocean pH - What's the Connection? Part A: CO2 and Ocean pH - What's the Connection? Oyster farmers sound the alarm about ocean acidification Oyster farmers have been on the front lines of ocean acidification. In Washington and Oregon, oysters ...

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