Predators are Important

        The article, “Aquatic Predators Affect Carbon-Storing Plant Life” by Janet Raloff, published on February 17, 2013, from Science News, can be found at http://www.sciencenews.or generic g/view//id/348348/description/Aquatic_pwredators_affect_carbon-storing_plant_life_

        A food web wouldn’t exist without producers, consumers and decomposers.  But what would happen if the top predator was removed? The top predators are usually the first organisms to disappear when pesticide runoff, overfishing or other human activities affect ecosystems. Losses of top predators don’t only cause less biodiversity, but it affects the climate and amount of carbon dioxide in the atmosphere. 

Three-Spined Stickleback

        A new study was done to show the effects of the food web if the top predator was removed.  The study leader, Trisha Atwood, and her colleagues simulated three freshwater ecosystems outside.  These ecosystems included streams near Vancouver, stimulated ponds in Vancouver, and water-holding reservoirs in Costa Rica.  The researchers added top predators to half of the simulated ecosystems in each location.  A three-spined stickleback was added to the streams.  Stonefly larvae served as the predator in the simulated ponds and damselfly larvae was added to water-holding reservoirs in Costa Rica.

        The researchers compared the data of the environments with and without the top predators at the end of the accommodation periods.  Atwood and her colleagues reported that, “Adding the top predators decreased the amount of carbon dioxide in the water by an average of 93 percent.”  The researchers think that this is because the zooplankton devours the algae and plants in each ecosystem when the predators are removed.  If the producers had not gotten eaten, they would have used and stored carbon, resulting in less carbon dioxide in the atmosphere. 

        Each animal plays a vital role in a food web.  If another species were to be added or removed from an ecosystem, the food web would be impacted greatly.  Before reading this article, when I heard the word “predator,” I associated it with bad because predators are the hunters and killers.  Now, it is clear that predators are just doing their job by keeping the other organisms from overpopulating.  It is necessary that humans take action, if not for the animals, then for themselves.                        

        In biology class, we learned that a food web is a diagram that shows the transfer of energy throughout each trophic level.  About ten percent of energy gets transferred from one trophic level to the next.  This means that the top predators get the least amount of energy.  Humans can’t help the fact that the predators are getting the least amount of energy, but they are just making the matter worse by overfishing and using an absurd amount of pesticide.  It is bad enough that many species are in danger of going extinct, but we can’t let a whole trophic level go, too.  

Citation for Picture:

Three-spined Stickleback. N.d. Photograph. Biology Post. Web. 11 Mar. 2013. <http://biologypost.files.wordpress.com/2013/01/three-spined_stickleback_1.jpg>.