Biological Processes Affected by Ocean Acidification
why carbon dioxide makes seawater more acidic
Scientists use pH—a measure of the concentration of hydrogen
ions using a logarithmic scale—as an indicator of the acidity of a
solution. As the hydrogen ion concentration increases, a solution
becomes more acidic and its pH decreases. Because the
scale is logarithmic, a decrease of one pH unit corresponds to
a 10-fold increase in acidity.
Calcifiers—organisms with shells or skeletons
made from calcium carbonate—are among the
most abundant forms of marine life. Ranging
from tiny plankton species such as pteropods and
foraminifera (pictured above) that form the basis
of marine food chains, to the vast coral reefs that
provide habitat for many ocean animals, calcifiers
are an essential part of many marine ecosystems.