Ocean acidification (OA) is defined as a reduction in ocean pH as a result of the absorption of anthropogenic carbon dioxide by surface waters (Hofmann et al. 2010). It is estimated that the oceans have become 30% more acidic since the beginning of the industrial revolution (Feely, 2004).
• Significance of the impact of human activity and the associated change on the ocean
o CO2 emissions from burning fossil fuels leading to increased uptake of CO2 by oceans-affecting marine life esp. organisms that use calcium carbonate to build shells, ocean is more acidic
o Moderates climate change by absorbing CO2 but reverse impact on ocean
• As a result of increasing CO2, commercial fisheries are now confronted with unknown future impacts from acidification. First, fish may experience direct physiological changes that impact metabolism, growth and reproduction. Second, the food web that supports them may be altered as their prey (e.g., pteropods), which require calcium carbonate structures, decline (marine-conservation.org)
This paper will analyze 2 accepted lines of evidence associated with ocean acidification. The first paragraph will discuss ocean-carbon chemistry while the second paragraph will examine coral reefs. Following the discussion of each line of evidence will be a detailed explanation of the problems and difficulties associated with using each of the lines of evidence addressed as indications for ocean acidification. To conclude, the paper will briefly re-address the significance of ocean acidification and the 2 supporting lines of evidence.
The concentration of CO2 in the atmosphere is now approximately 385 parts per million (350 ppm is a target level suggested to be the safe upper limit) and is likely to increase at 0.5% per year throughout the 21st century, a rate 100-times faster than has occurred in the past 650,000 years (Meehl et al. 2007). This increase will likely lead to a pH drop in the oceans of 0.3-0.4 units by the end of the century (Feely et al. 2008), a 150% increase in acidity (since the industrial revolution).
Evidence 1: Ocean Carbon chemistry
The first line of evidence this paper will discuss is ocean carbon chemistry. Oceans exchange carbon with the atmosphere in the form of carbon dioxide. The ocean...