By Thor-Wiggo Skille
This article first appeared in the Institute of Marine Research supplement to Aftenposten November 30, 2009:” Ocean, Climate, and the Environment”
Shells Lacking Substance Measurements of pH in marine ecosystems have been taken routinely only since the early 1990s. However, a series of observations confirm one negative development: all organisms that use shells made with calcium carbonate ― either to protect their bodies, or as hiding places ― will be affected. As explains Knut Yngye Børsheim: oceanographer at Norway’s Institute of Marine Research. Over millions of years the marine environment has been saturated with substances that permit calcium formation. But with increased input of CO2, amounts of calcium carbonate have decreased. As result, the very building blocks for calcareous structures are lost.
Animals that depend on shells made of calcium must use substantial amounts of energy to form their own calcerous structures. Mussels for example, could disintegrate if the ocean does not have adequate amounts of calcium carbonate. We can perhaps live without coral reefs, but what about other unanticipated effects? What would happen to copepods, krill, and other key species that form the food chain? If these species are impacted, then large fish stocks will be jeopardized. Børsheim believes that “we must quickly conduct research to understand the consequences of ocean acidification”.
Some zooplankton species that have shells made of calcium carbonate are facing some pretty hard times. After only a 24-hour period in slightly acidic salt water, it becomes apparent that their thin shells have begun to erode, Børsheim explains. He believes that ocean acidification can be detrimental for many marine organisms. We are also concerned about the eggs – an extremely vulnerable stage for these species ― which are directly exposed to the acidic sea water.
Need to Know
If present trends continue, in another hundred years human beings run the risk that ocean’s pH levels will have fallen from 8.1 to 7.7. Børsheim would like to be prepared, but we don’t know what this new ecosystem holds in store. In just 20 years from now, we will see things that we’ve never seen before. At this point, not knowing just what to expect is the greatest problem that we face.