Animal induced ocean mixing: primary vs. secondary

In “Sea Animals Change Climate Via Flutters and Flaps?”, National Geographic’s Brian Handwerk debates the impact of animal induced ocean circulation based on Kakani Katija and John O. Dabiri’s research paper “A viscosity-enhanced mechanism for biogenic ocean mixing”, published in the July 30 2009 issue of Nature. Though Handwerk wrote his review article as a presentation of Katija’s research, differences between the two papers are immediately distinguishable. There are three main reasons for these differences: (1) Katija was directly involved in the research and based her article on the results of her research, whereas Handwerk based his article on the results of Katija’s research. (2) Handwerk and Katija wrote their papers according to different target audiences, which is (3) the reason behind the differing claims or objectives in their articles.

Katija herself, along with colleagues, is responsible for the research behind her peer reviewed article. As the one who designed the experiment, did the calculations, and derived conclusions based on the empirical and numerical results, Katija wrote her research paper in great detail, including: the basis of the research; the exact procedures of the experiment; the materials and equipment used; a complete method summary; and complex calculations, graphs, and charts. When presenting Katija’s research in his article, Handwerk excludes the details of the research and covers only the simplified basics of Katija’s research, answering in simple explanations the ‘who’, ‘what’, ‘when’, ‘where’, ‘why’, and ‘how’ of Katija’s research.

The difference in the format and presentation of Katija and Handwerk’s articles is directly related to their different target audiences. Katija had to write her article in great detail of the research, since her target audience is the scientific community, with the knowledge that the scientific community would understand the complexity of the concepts and calculations. For example, in the article she refers to the limit of Stokes flow, the flux Richardson number, and the calculation of the Reynolds number without explanation. This is because it is fully expected that her audience understands these concepts already. Handwerk, on the other hand, had to simplify Katija’s research results. Handwerk’s audience is the public who are interested in nature and science, as the article is published in National Geographic. But they do not understand the complexities behind scientific research, and Handwerk adjusts accordingly.

Beyond the components and the format, the claims of the articles are also considerably different. Again, this is due to the difference in target audiences. In the original peer reviewed primary source article, Katija presents her research, data, and findings to support this presented claim:

“On the basis of calculations of a broad range of aquatic animal species,… biogenic mixing via Darwin’s mechanism can be a significant contributor to ocean mixing and nutrient transport…Therefore, neglect of the contribution of induced drift in theoretical models of the mixing efficiency…would result in an order-of-magnitude underestimate.” (Katija 2009).

Biologically generated turbulence has been largely ignored as a contributor to global ocean circulation due to the Ozmidov buoyancy length scale, which, simplified, concludes that the turbulence caused by animals is too small, and lost as heat before it can affect ocean mixing. But Katija, through her research results, claims that the other mechanism of fluid mixing - first presented by Charles Darwin and neglected by the scientific community - overcomes the Ozmidov scale due to induced fluid drift, the turbulent wake caused by the vertical motion of a solid body through high and low density fluids of the ocean, and is effective enough to rival the effects of winds and tides. She argues, therefore, that biogenic ocean mixing must be considered in theoretical models and in ocean circulations. While Katija focuses on the mechanism of fluid mixing, Handwerk writes to appeal to the audience and focuses on the significance of animal induced ocean mixing as a whole. He includes quotes from both supporters and critics, and stresses the importance of how this could affect global warming models, since ocean circulation is important in its contribution to climate. In this way, Handwerk’s claim becomes focused on the popular and widely debated issue of global warming, which he uses to attract a larger public audience.

By comparing Handwerk and Katija’s articles, it is evident that there is a significant difference between the secondary source and the primary. Unfortunately, this illustrates how distorted information can become, even unintentionally. By not focusing on the mechanism as Katija did, Handwerk appears to be stating that according to research, any movement in the ocean will affect ocean circulation. From the example of Handwerk and Katija’s articles, it is clear that when wanting to gain reliable information or form a solid opinion, one must make it one’s responsibility to search beyond the secondary source for the truthful facts, untouched by the media.

References

Handwerk, B. (2009). Sea animals change climate via flutters and flaps?. National Geographic, 30 July 2009. http://news.nationalgeographic.com/news/2009/07/090729-jellyfish-ocean-global-warming_2.html. Retrieved 6 October 2009.

Katija K, Dabiri JO (2009). "A viscosity-enhanced mechanism for biogenic ocean mixing." Nature, vol. 460, pp. 624-626.
(http://www.its.caltech.edu/~kakani/Katija_Dabiri_Nature_2009.pdf)