Environmental Engineering Reference
In-Depth Information
environment and have profound social impacts in the trop-
ics—especially on fishing and tourism. The loss of coral reefs
would also reduce the protection that they offer coastal com-
munities against storm surges and hurricanes.
Hasn't ocean pH changed in the past? Why is this different?
Will marine organisms be able to adapt?
Ocean pH has changed in past geological ages. But the rate of
change then was very slow—over many thousands of years.
Today's pH change is extremely fast—over one or two hun-
dred years. In the slow changes, processes like rock weath-
ering and seafloor mineral dissolution could counteract some
of the changes. But now the change is happening too fast for
slow geological processes to counteract. While some marine
organisms will be able to tolerate these conditions or evolve
adaptations, the changes may be happening too fast for many
organisms to tolerate or be able to evolve adaptations.
Which species are most threatened by ocean acidification?
Ocean acidification impairs the process of calcification for
building shells, which means that calcareous plankton (includ-
ing some phytoplankton at the base of oceanic food webs), cor-
als, shellfish—anything that builds a shell—is at risk. Among
the plankton in the oceans are tiny mollusks called pteropods
that play an important role in the oceanic food web. Because
they produce an aragonite shell, they are expected to be very
sensitive to ocean acidification. They make up a large part
of the diet of Alaska's juvenile pink salmon, which could be
affected indirectly through loss of food. Shellfish with weaker
thinner shells would be less able to resist shell-crushing
predators.
Some acidity is natural in some regions. Water off the
Pacific coast of the United States already has a low carbon-
ate saturation state. When surface winds blow the top layer of
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