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Edu: 711
SCIENCE AND
TECHNOLOGY
TOPIC ; OCEAN
ACIDIFICATION IN THE
PACIFIC
.
What is Ocean Acidification
When carbon dioxide (CO2) is absorbed by seawater, chemical
reactions occur that reduce seawater pH, carbonate ion
concentration, and saturation states of biologically important
calcium carbonate minerals. These chemical reactions are termed
"ocean acidification" or "OA" for short. Calcium carbonate
minerals are the building blocks for the skeletons and shells of
many marine organisms. In areas where most life now
congregates in the ocean, the seawater is supersaturated with
respect to calcium carbonate minerals. This means there are
abundant building blocks for calcifying organisms to build their
skeletons and shells. However, continued ocean acidification is
causing many parts of the ocean to become under saturated with
these minerals, which is likely to affect the ability of some
organisms to produce and maintain their shells.
What causes ocean
acidification
 Ocean acidification is a global environmental
issue caused by the man-made release of carbon
dioxide into the atmosphere.
How human activities causes ocean
acidification
Coastal waters are also affected by excess nutrient inputs, mostly
nitrogen, from agriculture, fertilizers and sewage. The resulting
chemical changes lead to large plankton blooms, and when these
blooms collapse and sink below the surface layer the resulting
respiration from bacteria leads to a drawdown in seawater oxygen and
an increase in CO2, which decreases pH even more in subsurface
coastal waters. One of the major differences between OA and these
types of human effects is that OA’s influence is truly global in scale,
affecting pH-sensitive and calcifying organisms in every ocean basin
from the equator to the poles.
How ocean acidification
affects marine life?
Corals, mussels, snails, sea urchins and other marine organisms use
calcium (Ca) and carbonate (CO3) in seawater to construct their calcium
carbonate (CaCO3) shells or skeletons. As the pH decreases, carbonate
becomes less available, which makes it more difficult for organisms to
secrete CaCO3 to form their skeletal material. For animals in general,
including invertebrates and some fish, CO2 accumulation and lowered
pH may result in acidosis, or a build up of carbonic acid in the
organism's body fluids. This can lead to lowered immune response,
metabolic depression, behavioral depression affecting physical activity
and reproduction.
Ref :https://www.sfos.uaf.edu/oarc
Examples of how oceans acidification
affecting the marine life
Pteropods
The pteropod, or “sea butterfly”, is a tiny sea creature about the
size of a small pea. Pteropods are eaten by organisms ranging
in size from tiny krill to whales and are a major food source
U.S. The photos below show what happens to a pteropod’s
shell when placed in sea water with pH and carbonate levels.
The shell slowly dissolves after 45 days.
Ref:Photo credit: David Liittschwager/National Geographic Stock. Used with permission. All rights reserved. National Geographic Images.
Shellfish
In recent years, there have been near total failures of developing oysters
in both aquaculture facilities and natural ecosystems on the West Coast.
These larval oyster failures appear to be correlated with naturally
occurring upwelling events that bring low pH waters undersaturated in
aragonite as well as other water quality changes to nearshore
environments. Lower pH values occur naturally on the West Coast
during upwelling events, but a recent observations indicate that
anthropogenic CO2 is contributing to seasonal undersaturation. Low pH
may be a factor in the current oyster reproductive failure.
Ref :Photo: Freshly harvested oysters from Yaquina Bay, Oregon (Credit: NOAA)
Ocean acidification leads to other
oceanic concern
Due to human activities there is higher rate of carbondioxde released in
the atmosphere. The oxygen in the sea water and carbon dioxide used
up to photosynthesis of the seaweeds . If there is high rate of
photosynthesis there will be high growth in the sea weeds. The sea
organism hardly survives due to lack of oxygen in sea for them to
breathe. This result in eutrophlication.
The Biological Impacts of ocean
acidification
Ocean acidification is expected to impact ocean species to varying
degrees. Photosynthetic algae and seagrasses may benefit from higher
CO2 conditions in the ocean, as they require CO2 to live just like plants
on land. On the other hand, studies have shown that a more acidic
environment has a dramatic effect on some calcifying species, including
oysters, clams, sea urchins, shallow water corals, deep sea corals. When
shelled organisms are at risk, the entire food web may also be at risk.
Today, more than a billion people worldwide rely on food from the
ocean as their primary source of protein. Many jobs and economies in
the U.S. and around the world depend on the fish and shellfish in our
oceans.
Ref :http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F
Impact of ocean acidification on
the world
Ocean acidification adversely affects many marine species, including
shellfish, and corals. As ocean acidification increases, the availability
of calcium carbonate will decline. Calcium carbonate is a key building
block for the shells and skeletons of many marine organisms. If
atmospheric CO2 concentrations double, coral calcification rates are
projected to decline by more than 30%. If CO2 concentrations continue
to rise at their current rate, corals could become rare on tropical and
subtropical reefs by 2050
Ref :http://www.epa.gov/climatechange/science/future.html
Impact of ocean acidification in the
pacific countries
According to Timm, and Henry ( 2009) Ocean acidification due to
rising carbon dioxide levels poses an additional threat to coral reefs
and the rich ecosystems they support. At the current rate of increase,
atmospheric CO2 concentrations will reduce the saturation state of
carbonate minerals in the surface ocean over the next 70 years until
nearly all the locations of coral reefs are at or beyond their normal
environmental limits. It will affect the United States with additional
extensive coral reefs in the Mariana Islands, American Samoa, and
National Wildlife Refuge islands and atolls throughout the Pacific.
Coral reefs are particularly sensitive to the impacts of climate
change as even small increases in water temperature can cause coral
bleaching. Bleaching of coral can be induced by long-term exposure
(i.e. several weeks) to temperature increases.
Localized and large scale coral bleaching have been observed in Hawai`i
(1986 -1988, 1996, 2002) during periods of high sea surface
temperatures (Jokiel and Coles, 1990; Jokiel and Brown, 2004) and the
acidification has been observed to have a profound impact on Hawai‘ian
crustose coralline algae, reducing growth and calcification by as much as
20% (Jokiel et al. 2008). Acidification will inhibit, and eventually end,
the growth of biota that rely on calcium carbonate structures (e.g., coral
reefs, plankton, and mollusks) and so disrupt the marine food web.
Impact of ocean acidification in Fiji
island.
Adverse effects of ocean acidification caused by increased absorption of
carbon dioxide by the oceans, are among the biggest threats to the health
of oceans and coastal areas. Ocean acidification affects the marine
ecosystem and disturbs the food chain.
Ref;http://www.bing.com/images/search?q=images+of+impact+of+ocean+acidfication+on+the+
food+web&FORM=HDRSC2#view=detail&id=257B966640A3F850CE49AA3F60B141029F49E44A
&selectedIndex=23
Possible solutions to ocean
acidification issue
Reduce burning of fossil fuel in the environment
. Oceana is working to reduce the cause and effects of
ocean acidification by promoting government policies to
cap CO2 emissions, eliminate offshore drilling, and by
advocating for energy efficiency and alternative energy
sources such as wind power and more.
Reducing human activities which results in Ocean
acidification.
Conclusion
It can be concluded that higher rate of carbon dioxide in the
atmosphere causes ocean acidification . Ocean acidification affects our
marine ecosystem and coral reef. It also affects the economic
development of some pacific countries . Human activities results in
enhance Green house effect that mean there is excessive carbon
dioxide in the atmosphere , which affects the nature balance. Ocean
acidification causes water acidification which affects the growth of
the seaweeds.
My view on ocean acidification
My view is that ocean acidification is similar to physic rule which
state that every reaction has equal or opposite reaction this simply
means that every action that humans takes has impact on the
environment . For example human activities that release excessive
carbon dioxide in the atmosphere results in ocean acidification .
Ocean acidification leads to other issues such as coral bleaching
and eutrophlicaton .ocean acidification also affects human, there
will be no sea food due to affect in the food chain and marine
ecosystem. What human do , is what human have.
Reference
Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson (eds.).
United States Global Change Research Program. Cambridge University Press, New York, N
h ttp://www.epa.gov/climatechange/science/future.html
•.
USGCRP (2009). Global Climate Change Impacts in the United States
•Jokiel, P.L., K. S. Rodgers, I. B. Kuffner, A. J. Andersson, E. F. Cox, F. T. Mackenzie. 2008.
Ocean acidification and calcifying reef organisms: a mesocosm investigation. Coral Reefs (2008)
27:473–483.
•Ocean Carbon and Biogeochemistry Program, Subcommittee on Ocean Acidification. December
2, 2008. Ocean Acidification- Recommended Strategy for a U.S. National Research Program.
•Timm, Oliver and Henry F. Diaz. 2009. Synoptic-statistical approach to regional downscaling of
IPCC twenty-first century climate projections: seasonal rainfall over the Hawaiian Islands.
Journal of Climate. Vol. 22:4261-4280
•United Global Change Research Program. May 2009.
http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts/regionalclimate-change-impacts/islands
•Riebesell et al. (2000) Reduced calcification of marine phytoplankton in response to
increased atmopsheric CO2, Nature 407, 364-367.