JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, C09S04, doi:10.1029/2004JC002671, 2005

Ken Caldeira (Carnegie Institution) and Michael E. Wickett (LL National Laboratory) have performed an experiment that uses ocean models to predict the changes in ocean chemistry due to carbon dioxide (CO2) absorption. In this study, simulations of CO2 are injected into “the deep ocean interior,” while criteria such as aragonite undersaturation, calcite undersaturation, and pH level are measured. For the emission of CO2, two different pathways are considered 1) century-scale SRES pathways and 2) pathways that release a certain amount of CO2 over several centuries.

Some of the main results compiled include the fact that 5,000 Pg C causes aragonite undersaturation in the majority of the ocean, while 10,000 Pg C produces calcite undersaturation as well. Simulations of the SRES pathways predict a global pH drop of about .3-.5 units by 2300. And also by the year 2300, CO2 emissions of 5,000 Pg C are predicted to produce a .8 drop in pH, while those of 20,000 Pg C will produce a 1.4 unit drop. Thus, the results and simulations show that the changes in ocean chemistry caused by CO2 injection (analogous to anthropogenic absorption) are biologically significant.

Journal of Limnology and Oceanography, doi:10.4319/lo.2010.55.6.2424 (2010)

Since the dawn of the industrial age, oceans have been absorbing about 1/3 of the massive amounts of CO₂ that humans have produced. When ocean water absorbs CO₂ it makes carbonic acid which acidifies the ocean and decreases the saturation state of calcium carbonate (CaCO₃). This event has consequences for organisms that rely on high saturation states to build their shells and skeletons.

In this study led by Li-Qing Jiang, the researchers monitored the saturation state of the water off of the coast of the southeastern US from 2005 to 2006. They found that in all cases the water was supersaturated with CaCO₃. They also concluded that the saturation state of East Coast water was higher than that of West Coast water due to the age of the water in global circulation and the upwelling that occurs in the Pacific Ocean.

Climate Policy Vol. 4, pages 377-398 (2005)

Support for any project relies on the public’s perception of the problem at hand.   Simon Shackley and colleagues at the University of Manchester conducted a study to understand the public perceptions of off-shore CO2 capture and storage (CCS), (when initially presented to the idea and after more background information was given) and perceptions of the key risks of CCS.

To determine the public’s perception, two Citizen Panels were run. They found that no participants were familiar with CCS before the interview, and therefore most were neither for nor against the idea. Among all the given risks, the most common concern about CCS was the leakage of CO2 from reservoirs, but still the majority felt that CCS was necessary for decarbonization.  Even though the information was present to the two panels quite differently, they had very similar opinions about CCS.   The researchers concluded that basic concern for climate change is required for the consideration of CCS as a legitimate decarbonization option.

Feel the Breeze

Journal of Engineering and Applied Science, DOI: 10.3923/jeasci.2011.141.146

Electrical power is a commodity often taken for granted by people living in industrialized countries. However, for much of the world electricity is not readily available and is expensive if it is available. Most methods of generating power are also bad for the Earth because of the amount of CO2 that they generate.

Wind energy is a cheap, clean source of energy that can be installed in some viable locations.. In his study on wind in Nigeria Olayinka Ohunakin studied six particular sites to assess their potential. He found that with 339.85 and 368.95 W/m² respectively Kano and Katsina are well suited to wind turbines. Gusau with an annual mean power density of 178.48 W/m² is another good location but will require a taller turbine to be effective. The other three locations, Kaduna, Bauchi, and Potiskum fell into the marginal potential category.

The ocean has absorbed carbon dioxide (CO2) from the atmosphere since the beginning of time. The ocean is known as a carbon dioxide sink because of its absorption capabilities. This has been viewed as a positive in the past few decades since global warming has become a pressing issue. The ocean absorbs CO2 from the atmosphere, which helps lessen the threat of global warming to the earth. Carbon dioxide levels have risen since the Industrial Revolution due to automobile emissions, cement production, industrial power plants and other contributing factors. Now, with the oceans absorbing absorbing about 1/3 of the earth’s carbon dioxide, the sea chemistry is being affected. The ocean cannot handle such high levels of CO2 as a result, its pH is becoming more acidic. This effect is known as ocean acidification.

Before the Industrial Revolution, the ocean’s pH levels were stable. Since then, the pH has dropped 0.1 units. Though this may seem like a relatively small change, the world’s ocean has a very high buffering, or acid neutralizing, ability so the fact that the pH has declined to this extent is very startling. PH levels are predicted to drop even more in the next century.

Like all ecosystems, marine ecosystems are comprised of a vast array of interactions between different species and different types of organisms (both alive and dead) and the physical environment. Therefore, a change in any of these aspects will lead to a plethora of changes throughout the rest of the ecosystem. Because of the sheer quantity of life present and the significant interactions between species, coral reefs are prime candidates to be affected greatly by ocean acidification. These reefs provide food and shelter to hundreds of thousands of marine organisms so when the reef is harmed by acidification, so are all of the organisms that interact with it. When global warming, one of the world’s most alarming environmental threats directly affects the coral reef, one of the ocean’s most important ecosystems, the ramifications are dire.

Coral reefs are created by large calcium carbonate colonies known as coral. These reef structures are the home and feeding grounds to a wide array of organisms. Coral reef ecosystems have been called “cradles of evolution” because more marine organisms evolve from coral reefs than from any other ecosystem.

Ocean acidification may actually alter the physical structure of coral reefs. Acidification affects the organisms that build the reef because it lowers calcification rates and pH, inhibiting the creature’s skeletal growth. Without these reef-building organisms, coral reefs cannot exist.

Aside from hindering the organisms that physically build the reefs, ocean acidification also increases the probability that existing reef structures may dissolve. Reef erosion is likely, given the vulnerability inevitable with increased acidification.

Acidification raises the possibility of coral mortality. It can cause coral bleaching, which can cause the coral to die. As the coral tries to survive and is in a weakened state, they become vulnerable to encroachment by other marine organisms. Some species can benefit from higher water acidity, like macroalgae. As these algae thrive, they block sunlight from getting to the coral and they may be abrasive to coral structures as they move through the water in the current.  Both low light and abrasive contact can weaken the coral, or even kill the reef structure.

Dissolving and eroding coral reefs, as well as coral that is lost because of displacement by other organisms that can survive better in the high acidity all lead to what is known as “reef flattening”. This is a phenomenon that creates a loss in the “architectural complexity” of the reef.  This affects all of the organisms that live within and rely on the reef as a key part of their survival methods. Reef flattening diminishes reef structure and habitats, and reduces organism populations and biodiversity.

Coral reefs are home to over 25% of all known species of fish and exhibit the highest biodiversity of any ecosystem in the entire ocean. Threats to coral reefs are a threat to thousands of other organisms, so as we see ocean acidification harming our world’s coral reefs, we should be very concerned.  Ocean acidification does not mean that the oceans will die, but the survivors may be algae and jellyfish.  For the ocean to be sustainable in its present form, with coral reefs the prominent sanctuaries for marine life, the pH of the ocean has to maintain acidity within relatively narrow boundaries.  With the alarming increase in CO2 being absorbed into our great carbon dioxide sink known as the ocean, the coral reef is in jeopardy.

Sources:

“Chapter 4.” Ocean Acidification: a National Strategy to Meet the Challenges of a Changing Ocean. Washington, D.C.: National Academies, 2010. Print.

Eilperin, Juliet. “Growing Acidity of Oceans May Kill Corals.” The Washington Post: National, World & D.C. Area News and Headlines – The Washington Post. 5 July 2006. Web. 04 Sept. 2011. <http://www.washingtonpost.com/wp-dyn/content/article/2006/07/04/AR2006070400772.html>

Although there exists a plethora of hypotheses on how ocean acidification will affect marine life, many argue that these are, in fact, just theories, made by over-zealous scientists trying to scare the population into living more sustainably. However, during a recent research study on the effects of low pH levels on coral reefs, scientists were able to observe these effects in a completely natural environment, making their conclusions more real and alarming than ever.

Coral reef ecosystems are known for their vivid colors and majestic aura, and as a result, the tourism industry racks up billions of dollars in hotel and tour revenue from people eager to experience them. However, the amount of healthy coral reefs has been decreasing rapidly. Although many hypotheses exist about why this is happening, ocean acidification is usually near the end of this list, apparently being only a small threat and playing only a minimal rule in destructing this ecosystem. Recent research, however, has found the opposite to be true.

The basis of a coral reef is calcium carbonate. Calcium carbonate is a precipitate only in slightly basic environments such as marine waters, and when placed in a more acidic environment, starts to dissolve. So naturally, one would think that the acidification of the ocean would be a crucial problem for the coral reefs. However, so far, the acidity of the ocean has decreased by only .1 pH unit. What would happen if marine pH were to decrease even more? By studying volcano fissures on the ocean floor, scientists were able to see the answer to this question firsthand. These fissures released CO2 into the water and consequently lowered the water pH by .4 units, causing temporary ocean acidification. In such an environment, nearby coral reefs were completely unable to grow and function, becoming completely crippled and lifeless.

In this scenario, healthy reefs that were less affected by the volcano fissures were eventually able to supply the underdeveloped coral reefs with calcifying macroalgae (or reef builders) and bring them back to a standard degree of vitality. However, what would happen if acidification prevailed throughout the entire ocean? Coral reefs would have no “back-up” reefs to save them. The continued acidification of the ocean will definitely have a disastrous effect on the world’s reefs, slowing disabling this beautiful yet delicate ecosystem until its complete decline.

Bibliography:

Ball, Kieran. “Ocean Acidification Threatens Coral Reefs.” Earthtimes.com. Earth oooooTimes, 30 May 2011. Web. 03 Sept. 2011. <http://www.earthtimes.org/nature/ocean-acidification-threatens-coral-oooooreefs/936/>.

“Damage to World’s Coral Reefs Threatens Tourism.” USAToday.com. USAToday, 11 oooooJune 2006. Web. 03 Sept. 2011. <http://www.usatoday.com/travel/destinations/2006-11-06-coral-oooooreefs_x.htm>.

Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean. Washington, D.C.: National Academies, 2010. Print.