In the oceans, marine bacteria play a role in the carbon cycle. They help by absorbing the carbon, nitrogen, phosphorus and other organic byproducts produced when other organisms are decaying, and from waste products. This aids in the energy source and reproduction for the bacteria, and helps protect the ocean's pH. The ocean helps buffer the earth by absorbing carbon dioxide for the atmosphere. The bacteria are then able to provide the carbon for energy higher up the food chain as the bacteria themselves are consumed.
Jelly fish are in every ocean, and in some fresh water. Recently, it has been noted that there is an increase in jelly fish populations. This can be attributed to various reasons, including over fishing, climate changes (jelly fish prefer warmer climates), and increased nutrients in the water (from agricultural/industrial run-off). There has also been a decrease in the number of predators of the jelly fish, such as sharks and tuna. When these conditions happen, the jelly fish populations can sky rocket. This is causing numerous problems. One is the danger to humans from jelly fish stings. This ranges from mild stinging to rare fatalities. Another problem has arisen in Japan, where the jelly fish have entered into power plants, causing some destruction by clogging various pipelines. But most importantly, they are eating large amounts of plankton. Plankton is made up of phytoplankton (algae), zooplankton (protozoans and metazoans), and bacterioplankton (bacteria and archaea). This is the food source for many marine animals from tiny shrimp to large whales. As more plankton is consumed by the jelly fish, the less food for the other marine animals, which will cause a decrease in the numbers of marine life.
When jelly fish come together, due to searching our warm waters, ocean currents, and abundance of food, they form what is called a "bloom." As the populations are growing, some of these blooms can have as many as 100,000 jelly fish in each one. A study done by Ph.D. graduate Rob Condon in 2011 at the Virginia Institute of Marine Science (VIMS) shows how these blooms are affecting the ocean ecosystem. When the jelly fish die, they form a large biomass of gelatin-like substance. As the oceans' bacteria work to decompose this, they are unable to properly absorb the carbon in this biomass. The bacteria us the carbon from these masses in respiration instead of energy and reproduction. Then they release more carbon dioxide into the oceans from this respiration. This is raising the levels of carbon in the ocean, forming a more acidic environment. This is affecting the life forms in the ocean both directly and indirectly. According to Dr. Carol Turley at Plymouth University's Marine Laboratory, this is "happening at a rate that hasn't occurred in 600 million years." (McVeigh, 2011) Ocean life cannot sustain itself in high levels of carbon, and the oceans are more unlikely to be able to absorb carbon dioxide from the atmosphere.
Another change is the type of bacteria found. Bacteria more adept to consuming the biomass will begin to flourish. Condon states that his team's findings "suggest major shifts in microbial structure and function associated with jelly fish blooms, and a large detour of energy toward bacteria and higher trophic levels." (VIMS, 2001)
McVeigh, T. (2011, June 12). Explosion in jelly fish numbers may lead to ecological disaster, warn scientists. The Observer.
VIMS. (2011, June 6). Jelly fish blooms shunt food energy from fish to bacteria. VIMS Press Release. Gloucester Point, Virginia: William & Mary University.
Condon, R. (2011, June 6). Jelly fish blooms result in microbial respiratory sink of carbon in marine systems. Proceedings of the National Academy of Sciences. Vol 108, no 25.