Nutrient Cycling/ Energy Flow

“A nutrient cycle is the movement and exchange of organic and inorganic matter back into the production of living matter. The process is regulated by food web pathways that decompose matter into mineral nutrients” (IPNI, 2014). Nutrient cycling or specifically the cycle of carbon and nitrogen is one that takes place in the arctic tundra biome where polar bears call their home.  In this cycle of nutrients, there isn’t just one way to cycle the nutrients; there are many ways. For example, the carbon cycle could start off with “phytoplankton and Algae taking up carbon dioxide from sea water and transforms it into the organic carbon of their tissue” (PolarDiscovery, 2006). Then consumers such as whales and fish consume the plankton and algae and take in this organic carbon. Even consumers prey on other consumers in the ecosystem that “converts their prey’s carbon into their own tissues or into sinking fecal pellets” (Polar Discovery, 2006). Then decomposers such as bacteria return the nutrients back into the soil in the arctic tundra, however, the consumers are capable of helping put carbon back into the ecosystem by breathing or respiring. Then the cycle repeats however it does not have to be in this order. However in the nitrogen cycle, there is only one specific way in which it can be completed. Nitrogen makes up 79 % of the atmosphere so when there is snow fall in the tundra, the snow is nitrogen rich and gets eventually deposited back into the soil. Once in the soil bacteria break down the nitrogen compounds into ammonia and then further more into nitrates. Plants benefit from the nitrites by absorbing then through their roots, turning the substance into nucleic acid and proteins, however, animals are only able to benefit from the nitrogen after the plants use it to make these proteins and nucleic acid. “ When animals die, or release waste, decomposers break it down and convert the nitrogen found there into ammonia then special bacteria change that to nitrogen and release it back into the atmosphere” (Prezi, 2014). In both of these cycles producers, consumers and decomposers play prominent roles yet also provide an energy flow in the environment. Energy transfers from producer to consumer to decomposer; however, only 10% of the energy gained from each organism is transferred to the next. (Eg. When a fish consumes a shrimp, the fish is only gaining 10% of the energy that the shrimp received from consuming algae. Then when a seal consumes a fish, the seal will only receive 10% of the energy that the fish gained from consuming the shrimp.) This is because when an organism receives energy it uses up the other 90% in order to live.

http://earthhealt.blogspot.com/2012/06/food-pyramid.html





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