Ocean Acidification – Sabi – Jan 12

You want info on ocean acidification? Read this (I wrote it in first year, give me a break for horrible writing):

Countless global issues plague our planet: severely overexploited resources, international conflicts, climate change, political unrest and many more. It is easy to see how less severe issues can get lost in the shadows of others. What is not so easy to understand is how an issue that directly affects almost 3/4s of our planet and indirectly affects the rest can be so largely ignored by the public and governments. Ocean acidification, often referred to as “the other CO2 problem”(Doney, Scot, C. et al, 2009), is an issue of growing concern to scientists, yet remains seemingly undiscovered by the mass public and insignificant to many governments despite the predicted impact on both marine ecosystems and society. The oceans, which cover approximately 70.8% of the surface on earth, are an incredibly important collection of ecosystems which human society relies on in a variety of different ways (Pidwirny, Michael et al, 2008.). They provide society with countless resources, recreation, and a sense of awe and discovery. The oceans are a natural carbon sink, absorbing more carbon dioxide from our atmosphere than any terrestrial biosphere; as the anthropogenic rate of CO2 emissions has increased drastically since the industrial revolution, the amount of carbon being absorbed into the ocean has also increased (Fabry, Victoria, J., Guinotte, John, M., 2009). Although the full extent of the consequences of ocean acidification are unknown, analysis of recent research suggests a highly negative outcome for marine ecosystems and our global society: marine ecosystems will be affected from the lowest trophic levels upwards and human society will face large economical and cultural losses.
Ocean acidification occurs when CO2 is absorbed into seawater, namely through hydrolysis, which increases the “hydrogen ion concentration [H+]” (Orr, James, C. et al, 2005)in the surface seawater. At the same time, the levels of carbonate ions in seawater are decreasing significantly, “making it more difficult for marine calcifying organisms to form biogenic calcium carbonate (CaCO3)” (Orr, et al, 2005) which they use to build shells necessary for survival. As a direct effect of increasing CO2 absorption, the pH of the ocean surface is “0.1 unit lower than preindustrial values. By the end of the century, it will become another 0.3–0.4 units lower” (Orr, et al, 2005) according to recent research. As the pH continues to lower, the surface waters of the ocean, particularly in the areas of highest productivity such as the Arctic and Antarctic, will become increasingly more acidic. As more CO2 is absorbed at a colder temperature, it is predicted that acidification levels will be at their most extreme at either pole. Most models on ocean acidification “suggest that 10% of the Arctic Ocean will be corrosively acidic by 2018; 50% by 2050; and 100% by 2100” (McKie, Robin, 2009) with similar, if not more severe predictions for the Antarctic oceans. The following image depicts the rising acidity levels throughout the oceans, and the effects of ocean acidification on calcium carbonate shells.

The analysis of research conducted on the effects of ocean acidification show that the rising acidity of seawater causes and will continue to cause tremendous amounts of stress on organisms from the lowest trophic levels of marine ecosystems all the way through to the higher levels. Ocean acidification affects marine organisms in several ways and is even more detrimental considering the other strains currently placed on the oceans globally. Most of the research conducted at this time revolves around organisms that build a calcium carbonate shell from the carbonate particles currently found in abundance in the ocean. Many of the “ marine organisms that form biogenic calcium carbonate include: crustose coralline algae (the primary cementer that makes coral reef formation possible), Halimeda (macroalgae), foraminifera, coccolithophores, tropical reef-building corals, cold-water corals, bryozoans, mollusks, and echinoderms” (Fabry, Victoria, J., Guinotte, John, M., 2009, pg. 321). Through laboratory experiments and research conducted on the last era of highly acidic oceans, it has been concluded that many of these species will face extinction, or struggle to survive in the changing marine environment. As the pH of the ocean begins to decrease and the acidity begins to rise, less carbonate ions are available for organisms to create the exoskeletal shell that they need to survive. This means that the organisms will be putting more effort into trying to create the shell and less energy into finding food, and reproducing. Although research on current ocean acidification has only really just begun, evidence of previous episodes of high acidity in the oceans is believed to be linked to the mass extinction of many species in the past; “Paleooceangraphic evidence shows that during the last high CO2 regime (55 million years ago) increased ocean acidification was associated with mass extinctions of phytoplankton species. This was followed by a recovery period of about 80,000 years.” (Zachos, J. C., et al, 2005).
If another mass extinction of phytoplankton species were to occur, we would see a massive ripple effect up through the different trophic levels of marine environments. Plankton and various other microscopic organisms form the backbone of coral reefs, where approximately one fourth of marine species can be found, and provide countless other species such as fish and baleen whales with their main source of food. Ocean acidification also affects marine animals in higher trophic levels through habitat change and loss, which can be observed through the relationship between cold water corals and fish. “Cold water corals biotherms have extremely high biodiversity and provide habitat and nursery areas for many deep-sea organisms, including several commercially important fish species(Rogers 1999; Fossa et al . 2002; Husebo et al . 2002)” (Fabry, Victoria, J., Guinotte, John, M., 2009, pg. 329). These cold water corals are predicted to be some of the most effected, as many of them survive in the regions of the ocean predicted to have the highest increase in acidity over the next 100 years.
There is also a direct correlation between ocean acidification and the effect on fish and other marine organisms. It would seem that there are both long-term and short-term effects on fish in particular, as studies show that “elevated CO2 levels on fishes include short-term alteration of the acid–base status, respiration, blood circulation, and nervous system functions, while long-term effects include reduced growth rate and reproduction (Ishimatsu & Kita 1999; Ishimatsu et al . 2004, 2005)” (Fabry, Victoria, J., Guinotte, John, M., 2009, pg. 335). Breaking down this statement, it is obvious to see the the physiology of fish can and will be effected, and that their population size will suffer from a decreased rate of reproduction. This will have a severe impact, especially on species that are already slow to reproduce or put under mass strain from human activities. Through the analysis of the information presented, it can be deducted that marine ecosystems will suffer severely under the impact of ocean acidification. A direct correlation can also be drawn between the impact on marine wildlife and human society.
Although issues concerning ocean acidification are often overlooked by current society, the impacts will soon rise to such a level that ocean acidification becomes impossible to ignore. We will see an impact on economies, livelihoods, and our simple ability to produce food form the sea. Globally, people are already beginning to see dwindling fisheries, changing ecosystems, and the mass pollution of their local marine environments (McKie, Robin, 2009). When you add all of these other issues with ocean acidification and the repercussions it will have on our oceans, the future seems to be a bleak place for marine animals and the humans who rely on them. Through the analysis of the effect ocean acidification will have on marine ecosystems, one can easily draw a parallel to the effect it will have on humans. Decreased reproduction of fish, especially those found in colder water, the eventual dissolution of carbonate shells in polar regions, and various other impacts will all severely effect international fisheries, resulting in another economical downturn (Gazeau et al 2007). “Laboratory studies suggest that mollusks, including species that support valuable marine fisheries such as mussels and oysters (Gazeau et al 2007), and especially their juveniles (Kurihara et al 2007, 2009, Cohen 2008, Barton 2009), are particularly sensitive to these changes. Societies dependent on marine calcifiers could consequently experience significant economic losses and even social disruptions over the next several decades” (Cooley, S. R., et al 2009). The following table shows a snapshot of the species important to fisheris that will be affected, and contrasts it to the significantly fewer species that won’t be as impacted by the changing ocean pH.

The areas that will be hit the hardest are coastal regions and third world countries that rely heavily on fisheries to provide them with an income and food for their families. Through the presented information, one can fairly accurately hypothesize that the change in pH level and rising ocean acidity not only severely impacts marine ecosystems, but poses to have a severe effect on global economies and livelihoods.
The ocean will continue to absorb carbon dioxide from the atmosphere through the natural cycle that has been in place long before the first human presence, continually changing the pH, CaCO3 concentration in seawater and acidity levels. It would seem that fighting ocean acidification is a losing battle, as there are few things that can be done to help slow ocean acidfication. Ocean acidification cannot be stopped, but it can be hypothesized that reducing carbon emissions will help slow the process, and trying to maintain a healthier relationship with the oceans will also have a positive effect. A healthier ocean will have a greater chance at surviving rising acidity levels, but factors such as mass pollution, over exploitation of fisheries, and temperature changes have all contributed to the rapidly declining health of the international marine environment (Weaver, Sigourney et al, 2009.) Changes need to be made both on land, and on the sea to help divert the disaster looming in the form of ocean acidification.
In conclusion, the analysis of data from various sources provides concrete evidence that ocean acidification is an issue of great importance. Through the loss of CaCO3 ions in seawater to the changing pH, microscopic organisms that form the backbones of intricate coral reef ecosystems will be negatively affected by acidification, an affect that will ripple all the way through the trophic levels to the largest of mammals, whales. Human cultures, economies and livelihoods will be severely affected by the potentially devastating affect of acidification on already dwindling global fisheries and rapidly changing environments( McKinnell, S. 2008). Ocean acidification continues to be overlooked by the public and governments despite the severe impact it will have on marine environments and human society.

Refrences:

Cooley, S. R., & Doney, S. C. (2009). Anticipating ocean acidification’s economic consequences for commercial fisheries. Environmental Research Letters, 4(2) pg. 3. doi: 10.1088/1748-9326/4/2/024007

Zachos, J. C., Röhl, U., McCarren, H., Kroon, D., Schellenberg, S. A., Sluijs, A., Hodell, D. A., Keely, D. C., Thomas, E., Nicolo, M., Raffi, I., & Lourens, L. J. (2005). Rapid acidification of the ocean during the Paleocene-Eocene thermal maximum. Science, 308, 1611-1615.

Doney, S. C., Fabry, V. J., Feely, R. A., and Kleypas, J. A. (2009). Ocean acidification: The other co2 problem. Annual Review of Marine Science, 1(1):169-192.

Cooley, S. R., & Doney, S. C. (2009). Anticipating ocean acidification’s economic consequences for commercial fisheries. Environmental Research Letters, 4(2). doi: 10.1088/1748-9326/4/2/024007

Guinotte, J. M., & Fabry, V. J. (2008). Ocean Acidification and Its Potential Effects on Marine Ecosystems. Annals of the New York Academy of Sciences, 1134(1), 320-342.

Orr, J., Fabry, V., Key, R., Lindsay, K., Maier-Reimer, E., Matear, R., et al (2005). Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature, 437(7059), 681-686.

Fabry, V. J., Seibel, B. A., Feely, R. A., and Orr, J. C. 2008. Impacts of ocean acidification on marine fauna and ecosystem processes. – ICES Journal of Marine Science, 65: 414– 432.

Pidwirny, Michael (Lead Author); J. Emmett Duffy (Topic Editor). 2008. “Ocean.” In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment).

McKinnell, S. 2008. Salmon pHishing in the northeast Pacific: an archaeological dig in the North Pacific survey data (1956-1964) – abstract at The Ocean in a High-CO2 World, Monaco October 2008.

Spalding M, Ravilious C, Green EP (2001) World Atlas of Coral Reefs. Univ. of California Press

Weaver, Sigourney et al, 2009. Acid Test: The Global Challenge of Ocean Acidification (documentary)

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