Radioactive Sushi

            Humans are at the top of the food web, above almost every organism in the animal kingdom. What we eat affects our health and well-being. If the organisms below us aren’t understood, humans can only hope that their health won’t be affected by eating them. Humans need to understand other organisms to ensure their ability to maintain healthy ecosystems in turn maintaining human health.

A Silver (Actually Cesium) Lining: Traces of Fukushima Disaster Fallout Help Scientists Track Tuna by Marissa Fessenden explores the effects of a radiation spill in the spawning grounds of Pacific Bluefin tuna. The power plant that is responsible for the radiation is located in Japan. The radioactive isotopes, cesium 134 and cesium 137, were in low enough levels that the fish and the humans that eat them remain unharmed. Cesium 137 is found throughout the ocean due to nuclear testing during the 1960’s, but cesium 134 is indicative of the tuna exposed to the Japan nuclear plant radiation. Researchers found tuna off the coast of California that tested positive for cesium 134 indicating that they had migrated from their spawning grounds near Japan. Because of its shorter half-life, researchers were able to determine how long the fish had been in the California area. The rate of decay of cesium 134 makes this technique time-sensitive, but the accidental labeling of the fish has opened up a wide array of different techniques to track the migratory patterns of the fish.

            In her book, Frankenstein’s Cat, Emily Anthes discusses her encounters with the cousin of the Pacific Bluefin, the Atlantic Bluefin. Unlike terrestrial animals, marine animals pose a problem with tracking their movements because of water inhibiting the signal transmission to satellites. Anthes describes a couple different methods for tracking tuna migratory patterns. The first is installing tracking systems into the tuna via surgical implantation. This form of tracking allows fishermen who find these tracking systems to return them for a reward and can gather data from anywhere between a few weeks to years. The downside to this method is that it is a highly invasive procedure and any surgery is not without its risks. The second method of tracking is a modification of the previous method, but the tracking device contains a segment that sticks out of the tuna’s body. This part detaches after a programmed period of time and sends a signal to a satellite so researchers can retrieve it. This method still contains the same problem because of the negative effects of invasive surgical implantation.

            Anthes also discusses the cloning technique nuclear transfer. This is a technique that takes existing DNA, say the DNA from a cat’s skin cell, and introduces it into a somatic cell that has its genetic material removed. The new egg will then be implanted in another female that will serve as a surrogate that will carry the embryo to term. This new organism will be a genetic twin to the organism that provided the DNA.

            To remedy the negative effects of surgical implantation of tracking devices, a new method of tracking fish could be devised. Using the cesium radiolabeling as a stepping-stone, scientists could theoretically insert a gene that provided a similar function as the cesium did. Isolating the Bluefin DNA, researchers could manipulate the sequence to express a gene that would produce proteins that degraded similarly to cesium 134 and 137. Using these fish to follow the path of migration, researchers could learn much more about Bluefin tuna than they can currently.

            The issue with introducing radioactive isotopes into the Bluefin environment is an ecological problem. If too much is introduced, the ecosystem could collapse because of the death of so many organisms, not to mention the paperwork and permission required from a number of different countries would be a nightmare. For researchers to understand more about the marine ecosystems, a new technique for studying migratory patterns and habitats needs to be developed. This accidental chemical fiasco could be instrumental in developing these needed techniques.

Anthes, Emily. Frankenstein's Cat: Cuddling up to Biotech's Brave New Beasts. 1st. Edition.  New York: Scientific American, 2013. Print.es, Emily
 

http://www.scientificamerican.com/article.cfm?id=cesium-lining-tuna