Download Guest speaker: Dr - Citizens` Climate Lobby Canada

CCL Monthly Conference Call – Saturday, February 2, 2013, 12:45 pm
Guest speaker: Dr. Martin Tresguerres, Scripps
Institution of Oceanography
Dr. Tresguerres will shed some light on global warming’s evil twin – ocean acidification,
which could lead to a collapse of the marine food chain if left unchecked. He is currently
working with a four-year grant from the National Science Foundation to study the effect
of ocean acidification on coral. He’ll share some preliminary findings from that study.
February Conference Call
Ocean acidification is the name given to the ongoing decrease in the pH of the Earth’s
oceans, caused by the uptake of anthropogenic carbon dioxide (CO2) from the
atmosphere (measured since the 1950’s). About 30–40% of the carbon dioxide released
by humans into the atmosphere dissolves into the oceans, rivers and lakes. To maintain
chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of
these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion
and a hydronium ion, thus increasing the ocean's "acidity" (H+ ion concentration).
Between 1751 and 1994 surface ocean pH is estimated to have decreased from
approximately 8.25 to 8.14, representing an increase of almost 30% in H+ ion
concentration in the world's oceans.
pH measures the concentration of H+ on a non-linear scale (logarithmic), consequently
slight pH changes (8.1 to 7.8 – his recent data) represent huge changes in acidity. The
lower the pH, the higher the acidity . The pH of the ocean is increasing at a very rapid
rate which is unprecedented in the history of the earth. He suggests it may be too fast for
organisms to adapt – some will be able to cope better than others.
This increasing acidity is thought to have a range of direct undesirable consequences such
as depressing metabolic rates and affecting metabolic processes in some organisms. Dr.
Tresguerres studies cell biology and processes in corals sharks, crustaceans and others
to look at how these organisms adapt (or not) to ocean acidification.
Other chemical reactions are also triggered which result in an actual net decrease in the
amount of carbonate ions available. In the oceans, this makes it more difficult for marine
calcifying organisms, such as coral and some plankton, to form biogenic calcium
carbonate, and existing structures become vulnerable to dissolution. Thus, ongoing
acidification of the oceans also poses a threat to the food chains connected with the
oceans.
Ocean acidification, which like global climate change is driven by increased levels of
carbon dioxide, has been regarded by climate scientists as the "equally evil twin" of
global climate change.
Largely from Wikipedia http://en.wikipedia.org/wiki/Ocean_acidification
Ocean Acidification Illustration
Ocean Acidification: The Other Carbon Dioxide Problem
Fundamental changes in seawater chemistry are occurring throughout the world's oceans.
Since the beginning of the industrial revolution, the release of carbon dioxide (CO2) from
humankind's industrial and agricultural activities has increased the amount of CO2 in the
atmosphere. The ocean absorbs about a quarter of the CO2 we release into the atmosphere
every year, so as atmospheric CO2 levels increase, so do the levels in the ocean. Initially,
many scientists focused on the benefits of the ocean removing this greenhouse gas from
the atmosphere. However, decades of ocean observations now show that there is also a
downside — the CO2 absorbed by the ocean is changing the chemistry of the seawater, a
process called ocean acidification.
http://www.pmel.noaa.gov/co2/story/Ocean+Acidification
Questions
1. Any possibility of carbon sinks in the ocean?
Variability exists in the ocean but he has no knowledge of potential side effects of
interference.
2. Can the process be mitigated?
CO2 in the atmosphere will continue to rise for seeral decades after emissions
have halted.
Urgent to dramatically reduce rate of carbon dioxide emissions.
3. How does ocean acidification vary with depth and latitude?
Complex – upwellings, and topography will influence values.
CO2 has higher solubility in colder temperatures
In general, pH data refers to ocean surface where most organisms live
Other stresses on ocean organisms include pollution and increased water
temperature.
Organisms are very resilient, but require more energy to cope with a single stress.
Multiple stresses leaves even less energy for metabolic processes such as
reproduction, digestion, etc.
He is doing some research in this… how stresses affect the cellular functions of
various organisms
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