Scientist presents key research at
national ocean acidification workshop
Dr. Mark Green
We are acidifying our oceans,”
says Dr. Mark Green, an environmental science professor who spoke
to a national workshop on ocean acidification at Scripps Institution
of Oceanography in California last month. The scientific community
has become interested in Green’s research on the effects of
lowered pH on juvenile clams and other small marine organisms with
calcium carbonate shells. Publications by Green in both 2003 and 2004
were the first to show that small organisms with calcium carbonate
shells are prone to dissolving and die-off when exposed to just slightly
lower oceanic pH – levels that we are now starting to see as
carbon dioxide (CO2) in the ocean increases.
Although the scientific community has known about global warming
for several decades, it was not until 2005 that anyone realized how
its root cause affected our oceans. It turns out that as humans add
roughly 7 billion tons of CO2 to the atmosphere each year by burning
fossil fuels and harvesting the rainforest, one-third of that dissolves
into the oceans, where it creates carbonic acid.
Ocean acidification will have a devastating effect on shell fisheries,
according to Green. His research shows that nearly 100 percent of
the larval clam community dies within several days of exposure to
pH levels already seen now in some regions of the oceans, and that
will be seen nearly everywhere by 2100. If none of the larval clams
are able to survive, it will only be a matter of years before entire
adult clam communities disappear, says Green.
The lowered pH will also dissolve several small phytoplankton species
that represent the very base of marine food webs, and the disappearance
of these microscopic plant species will cascade throughout the entire
ocean with devastating consequences.
“Most small and/or juvenile organisms can’t survive even
small decreases in pH,” says Green.
The workshop, sponsored by the National Science Foundation and National
Oceanic and Atmospheric Administration, gathered oceanographers together
in the hope of shaping future research, standardizing methods and
promoting collaboration among key scientists.
“It was designed to get people talking about ocean acidification
and immediately formulate research strategies to deal with this potentially
catastrophic problem,” Green states.
