Thursday, September 23, 2010

Carbon Dioxide Emissions and Fish

Primary vs. Secondary Articles

News articles are known to be accurate and precise, but how do they compare to their original findings? In this reading, primary and secondary articles will be deciphered to prove validity and strength of a certain argument. In the Daily Science article, “Carbon emissions threaten fish population”, it claims due to rising CO2 and ocean acidification, baby fish are impaired and are losing scent of predators, thus being consumed more rapidly.

The Differences

The difference between the primary and secondary articles is that the secondary article is written much simpler for the reader. The primary article is full of charts and statistics. For example a graph that shows how many fish are affected by different amounts of CO2.

The surroundings and environments stated are extremely important when looking for differences in the two articles. The secondary article says nothing in detail about the apparatus the fish were in but the primary says this, “Behavioral responses were tested in a two-channel flume chamber where larvae could choose between a stream of water containing the chemical cues of a common predator and a stream without that cue.” (Munday, 12930 (PDF)) There isn’t much variance in sample quality when there are only two places for a fish to go. In the primary article, only clownfish and damselfish larvae are tested for predator cues under the influence of acidified water. (Munday, 12933) The secondary article does not mention any other types of fish, just baby fish. This implies that the secondary article is claiming that all baby fish respond exactly like the clownfish and damselfish larvae. The reader would believe all baby fish are affected by CO2 levels and not just the clownfish, damselfish species.


Both articles only take one variable, (CO2) into consideration on why baby fish are dying. Is it possible that the predators are taking over because they are not being killed as much? There should be more research put into how many predators there are and why the mortality rate is so low. Another problem could be that the predators are not being hunted so the food chain is altered. Some predators might benefit from rising CO2 levels and thus more are living. CO2 level tests should be done on a variety of fish of all ages and size. Temperature, water pressure, and salt content of the oceans should be tested as well to create a variance of experimental results and see which is affecting the fish the most. Breeding patterns should also be taken into consideration; location of spawning currents may alter due to erosion and climate change.

More Differences

In the Secondary article it states, “As CO2 increases in the atmosphere and dissolves in the oceans, the water becomes slightly more acidic.” (ScienceDaily) Compared to the experimental data, ocean pH has decreased 0.1 units for as long as the world has kept track. So it has taken all this time to change the pH 0.1 unit? People would argue it is part of natural climate change or human caused climate change but this is not what we’re here to discuss. The actual experiment (primary article) that has been done involves ocean conditions predicted in the future. It was misleading because most people would have thought it was the ocean today. The experimental data of how the different levels of CO2 in parts per million resulted with the fish is only displayed in the primary article. The secondary news article only displays the main conclusions and overall effects on the environment. The secondary article claims that fish start becoming confused at about a 750ppm CO2 level. (Munday) The secondary article says, “The atmospheric CO2 levels will be 750-1000 ppm by the end of the century. This will acidify the seas much faster than has happened at any stage in the last 650,000 years.”(ScienceDaily) The ocean’s CO2 level was 280 ppm as of the year 1990. (Ahlbeck, 1999) The primary article does not contain information on how much of the total CO2 is directly from us humans. Some CO2 deposited into the ocean could be from natural causes (for example, the carbon cycle and water cycle). The primary article does not show any pattern or graph that the ocean’s CO2 level will be at 700- 1000 ppm at the end of the century which was stated in the secondary article.

In Summation, the primary and secondary articles differ by the depth of statistics and further research. Their similarities are the general idea of trying to show the concern for CO2 levels in the ocean but both articles need to consider other factors that may contribute which can be resolved by doing more variations of research. Overall the findings in the primary and secondary articles were isolated but give great insight to what will likely happen to certain baby fish in the future.


Ahlbeck, Jarl. "Increase of the Atmospheric Carbon Dioxide Concentration Due to Ocean Warming." Abo Akademi University, Finland, 1990, 15 Aug. 2008. Web. 23 Sept. 2010.<>.

ARC Centre of Excellence in Coral Reef Studies. "Carbon Emissions Threaten Fish Populations." ScienceDaily 27 July 2010. 22 September 2010 ..

Munday, Philip L., Danielle L. Dixson, Mark I. McCormick, Mark Meekan, Moad C.O Ferrari, and Douglas P. Chivers. "Replenishment of Fish Populations Is Threatened by Ocean Acidification." Proceedings of the National Academy of Sciences. PNAS, 20 July 2010. Web. 22 Sept. 2010.. .

Words: 901

Secondary Source:­ /releases/2010/07/100707091211.htm

Primary Source:

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