The Dirt

According to Wired Science, new scientific research on the world’s oceans suggests that marine animals may stir oceans as much as wind and tides do. This new understanding of marine life may end up changing current climate models.

Scientists are studying marine animals’ effect on large-scale ocean mixing, a process which distributes heat, gases, and nutrients around the ocean. While it was once believed that oceans simply absorb marine life movements, new work suggests that marine animals not only move water, but drag it along with them. In comments to Wired, Kakani Katija, a Cal Tech Engineer said: “The mere act of swimming implies that some water travels with the swimmer. Drift applies to all animals, anything with a body.”  

Katija studied the phenomenon using florescent dyes that outline the movement of water around a marine animal. With the dyes, Katija could demonstrate that a high-pressure field develops in front of the marine animal’s body and a low pressure field behind the body, resulting in water displacement. (See another article from The Daily Galaxy in which Katija further discusses fluid dynamics).

Katija’s research builds on other studies. According to Wired, studies have found turbulence generated by a swarm of krill, a very small crustacean. Additionally, another study has showed a large school of fish could cause as much turbulence as a storm.

William Dewar, a Florida State University oceanographer, argues that if marine animals create tidal-scale forces, there could be an impact on the global climate. Furthermore, Dewar added in commments to Wired: “How one would extend existing models to include a biosphere mixing input is not clear, largely because no-one has spent much time thinking about it.” More research needs to be carried out on “biogenic mixing,” and determining its impact on ocean circulation and climate.

Read the article and Katija’s research study in Nature.