The intimate chatter between grandfather and grandson accompanied by an eerie piano melody of impending doom, the nostalgic vignettes of a Norwegian childhood interrupted by dire warnings from oceanographers, and the tranquil images of floating pteropods juxtaposed with stark pictures of their disintegrating shells all serve to make the documentary A Sea Change a jarring narrative of the dangers of ocean acidification. Producer Sven Huseby is a master of persuasion, invoking apocalyptic diction to inspire fear. But often his ocean of argument is polluted by logical fallacies, marring its effectiveness as a catalyst of reform by turning his audience into skeptics.
The predominant rhetorical fallacies in A Sea Change are emotional—scare tactics employed to frighten viewers into changing their lifestyles. The concept of “mass extinction,” expressed in the movie’s very subtitle, “imagine a world without fish” implies that the oceans would become devoid of all marine life as a result of ocean acidification. This doubles as the logical fallacy of stacked evidence, representing only one side of the issue. Despite the fact that many species would suffer as a result of ocean acidification, the truth is some would be unaffected or even thrive in a more acidic environment. Of course we cannot expect a movie with the intention of informing the general public to go into the scientific complexities of ocean acidification. But an honest explanation of the dangers of a loss in biodiversity would be more effective than unrealistic predictions of apocalypse. After all, those who choose to watch documentaries on ocean acidification are most likely better educated than the general public.
A Sea Change struggles to send a definitive message. Can it really be regarded as a call to action when it offers no recourse for individual viewers to take? The opening suggests we have already been defeated. “We’re screwed,” declares one scientist at an ocean acidification summit; many others echo this view. Isn’t it futile to combat destiny? By overemphasizing the pre-ordained apocalyptic nature of ocean acidification at the start of the movie, the usefulness of emerging technologies mentioned near the end is called into question. In this way, rhetorical fallacies obscure, rather than strengthen, Huseby’s argument. A Sea Change is neither horror nor feel-good, nor even comprehensive or objective enough to be considered truly educational. Ultimately it fails in its purpose in effecting change by alienating educated, environmentally conscious viewers with illogical, emotionally driven reasoning.
Although there remains much to be learned about the biological effects of ocean acidification, certain aspects, such as the internal pH control of marine organisms, have been studied in great detail. Heterotrophic marine organisms rely on a concentration gradient of higher, internal, and lower, external levels of CO2 to expel the CO2 from the body resulting from natural metabolic processes (Ocean, 50). CO2 in the ocean permeates across biological membranes, dissolving in bodily fluids to form H+ and HCO3- ions. As CO2 levels in the ocean rise, the ability of marine organisms to regulate the acid-base balance becomes increasingly difficult. The condition of increased acidity in the blood and other body tissue is called internal acidosis.
A study at the Marine Biology Research Center in the UK examined the effect of environmental acidity on the purple-tipped sea urchin Psammechinus miliaris. It found that within a week all organisms died under severely acidic conditions with a pH of 6.16 (Miles, et. al). Hypercapnia, the condition of excess carbon dioxide in the blood, caused irremediable acidosis. Even at moderate levels of environmental hypercapnia, natural organismal buffering was insufficient to maintain homeostasis due to lack of efficient ion regulation in echinoids.
Single-celled coccolithophores, unlike most other calcifying marine organisms, produce calcified structures inside their cells before secreting them to the surface. Thus, they possess the unique problem of eliminating H+ ions within the cytoplasm quickly enough to prevent intracellular acidification (Taylor, et. al). According to a paper published by the Marine Biological Association of the UK, an understanding of the pH regulation mechanism of coccolithophores could yield information about coccolithophore response to future increases in ocean acidity. Coccolithophores use a voltage-gated H+ channel to expel hydrogen ions from its membranes. This might help explain why certain species of coccolithophores were observed to be unaffected, or even aided in the precipitation of calcium carbonate in increasingly acidic environments.
Most studies on the effect of ocean acidification on organismal calcification have measured only whether or not an organism would survive in acidic conditions without taking into account decreased competitiveness caused by weakened protective shells (Tyrell). A study by Fine and Tchernov that found that coral can survive without calcified skeletons ignores the fact that without a protective shell, coral would be ripe target for hungry fish. More comprehensive research needs to be done in the area of biological consequences of ocean acidification to give us a clear picture of what the future holds.
While the disparity in biological responses to changing oceanic conditions is fascinating, the impact of ocean acidification on organismal calcification, reproduction and physiology in thousands of species, including, coccolithophores, corals, foraminifera, echinoderms, crustaceans and mollusks is disconcerting. Even though a few species might survive or even thrive with a continuing decrease in the pH of the ocean, the vast majority of organisms would suffer greatly, drastically changing the biotic constitution of our oceans. In order for the government, private sector, or general public to take action, however, further research into the impact of changing ocean chemistry on marine organisms is required.
Fine, M., and D. Tchernov. “Scleractinian Coral Species Survive and Recover from Decalcification.” Science 315.5820 (2007): 1811. Print.
Mejia, Robin. “Will Ion Channels Help Coccolithophores Adapt to Ocean Acidification.” Public Library of Science Biology. Web. 4 Sept. 2011. <http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001087>.
Miles, Hayley, Stephen Widdicombe, John I. Spicer, and Jason Hall-Spencer. “Effects of Anthropogenic Seawater Acidification on Acid–base Balance in the Sea Urchin Psammechinus Miliaris.” Marine Pollution Bulletin 54.1 (2007): 89-96. Print.
Ocean Acidification: a National Strategy to Meet the Challenges of a Changing Ocean. Washington, D.C.: National Academies, 2010. Print.
Taylor AR, Chrachri A, Wheeler G, Goddard H, Brownlee C (2011) A Voltage-Gated H+ Channel Underlying pH Homeostasis in Calcifying Coccolithophores. PLoS Biol 9(6): e1001085. doi:10.1371/journal.pbio.1001085
Tyrrell, T. “Calcium Carbonate Cycling in Future Oceans and Its Influence on Future Climates.” Journal of Plankton Research 30.2 (2007): 141-56. Print.