Bridget Nittler
High School Junior
November/December 2024
In the intricate web of life detailed by the ecosystems around us, energy is transferred by organisms through the governing principle of conservation of energy. The principle of conservation of energy explores the idea that energy cannot be created or destroyed; rather, it is transformed into a new form and used for different purposes. A perfect example of this is seen in our ecosystem when organisms transfer energy by eating another organism or obtaining it from the sun. However, human activities such as pollution and habitat disruption can alter or prevent this energy from transferring within the ecosystem, which, as you can imagine, is incredibly disruptive and harmful to these organisms. Humans alter the energy transfer within an ecosystem through deforestation, pollution, and urbanization.
Firstly, humans affect the transfer of energy through deforestation. Deforestation involves the clearing of large areas, often by removing entire forests, for various purposes such as agriculture, urban development, or logging. This destruction of habitats disrupts local and global ecosystems by reducing biodiversity, altering carbon cycles, and affecting water and nutrient cycles essential for the health of an ecosystem. The trees in such a forest play a crucial role in the energy cycle by absorbing sunlight and converting it into chemical energy through photosynthesis (Amina). This process, known as energy transformation, is when one form of energy changes into another. Another example of this is a hydroelectric dam, which converts the kinetic energy of water into electrical energy. The energy from sunlight being transformed into chemical energy by the trees is also an example of energy conservation, as the energy from sunlight is not being created or destroyed; rather, it is being changed into a new form. While deforestation may not seem like a big deal, when large patches of land full of trees are cleared for urbanization or other reasons, the natural process of changing sunlight into chemical energy is disrupted. The energy from the sunlight that would have been absorbed by the trees is instead reflected back into the atmosphere, where it contributes to the greenhouse effect, trapping heat and leading to global warming. Without these important trees to soak up the energy and convert it into something new, more heat is radiated into the atmosphere, increasing global warming (Amina). Amina, the author of How Do Human Activities Disrupt Natural Energy Flows, sums this up perfectly in her article: "When large areas of forests are cleared for agriculture, urbanization, or logging, this natural process is disrupted. The energy that would have been absorbed and converted by the trees is instead reflected back into the atmosphere, contributing to global warming.” It goes without saying that global warming is incredibly disruptive to ecosystems around the world. The trees are the starting point for energy transfer throughout the entire ecosystem. Without the energy transfer from the sun, the trees are unable to provide energy to the other trophic levels. A trophic level can be described as the position of an organism in the food chain, ranging from a value of 1 for primary producers to 5 for marine animals and humans (Yodzis). From the starting trophic level, 90% of the energy from the previous trophic level is unavailable because it is used for movement, growth, respiration, and reproduction. Although some energy is lost through heat and waste, the previously stated reasons are the main contributors to this energy loss. Using this information, we can conclude that the remaining energy not used up through these other processes can be transferred to the next trophic level (Kate M). The transfer of energy from the sun to the trees is incredibly efficient. Sarah Jensen, author of Can We Calculate the Efficiency of a Natural Photosynthesis Process?, explains this efficiency: "Both photosynthesis and photovoltaic systems absorb very high-energy light, but plants are nearly 100% efficient at absorbing light from the visible spectrum—the range of colors from red to blue.” The process of photosynthesis helps to pass down energy from the sun to other trophic levels. When this process is disturbed by ecosystem disruption, the trees are unable to pass this energy down to the next trophic level. It goes without saying that deforestation would be outlawed, as it destroys the ways energy is transferred within an ecosystem. Other factors, such as pollution, also affect energy transfer.
Pollution is the introduction of harmful substances into the atmosphere, which can be detrimental to humans, animals, and other organisms. These pollutants, the term coined for these harmful substances, come from various sources such as industrial activities, transportation, agriculture, and waste disposal. Over time, these harmful substances accumulate, leading to long-term harmful effects for the environment, such as degradation. The types of pollution most harmful to energy transfers are water and air pollution. Air pollution can be described as the presence of substances in the air that can harm organisms and humans within a given space. Water pollution is the contamination of bodies of water, usually as a result of human activities such as agricultural runoff, oil spills, industrial waste, plastic waste, mining activities, deforestation, and urban runoff ("Difference Between Air Pollution and Water Pollution”). The burning of fossil fuels, natural energy sources formed from the remains of ancient plants and animals millions of years ago, releases large amounts of carbon dioxide and other greenhouse gases into the atmosphere. These greenhouse gases, such as carbon dioxide, methane, nitrous oxide, and ozone, trap heat from the sun in the atmosphere, preventing sunlight from being reflected back into space and interfering with photosynthesis. Without photosynthesis, energy is unable to be transferred throughout the ecosystem, showing how disruptive pollution can be to energy transfer. Similarly, water pollution also harms energy conversion, as it blocks underwater plants from obtaining the sunlight they need to survive and create energy (Amina). The article How Do Human Activities Disrupt Natural Energy Flows explains: "These plants need sunlight to perform photosynthesis, and without it, their growth and survival are threatened, disrupting the energy flow in aquatic ecosystems.” Murky water prevents many aquatic plants, such as seaweed, water lilies, and mangroves, from effectively capturing sunlight and converting it into the energy they need to survive. The energy transfer between sunlight and aquatic plants is also incredibly efficient, as the plants’ net primary productivity is higher because plants such as plankton can reproduce quickly, taking advantage of the plentiful supply of sunlight and nutrients found in the water (Raymond). All in all, pollution from industrialization, transportation, and other factors is incredibly harmful to the transfer of energy in ecosystems between different trophic levels.
Finally, urbanization is also a leading cause of the disruption of energy transfer within an ecosystem. Urbanization is the process by which people from rural areas move to urban cities, increasing the population and driving expansion and growth. The shift from rural to urban areas is often driven by economic opportunities, better access to education, healthcare, and other services. The effects of urbanization include the development of infrastructure, housing, transportation, and other resources needed to support the growing population. While urbanization may seem like a positive process, it leads to negative effects such as environmental degradation, including increased waste production, higher energy consumption, and the depletion of natural resources (Britannica). As these cities grow larger and more populated, natural landscapes such as mountains, caves, and volcanoes are replaced by concrete and asphalt, materials that absorb more heat from the sun than natural surfaces. This heat reflection creates an increase in local temperatures, known as the urban heat island effect. The energy used for heating, cooling, and lighting these large cities also increases the overall temperatures in the atmosphere. As previously mentioned, the reflection of heat into the atmosphere prevents sunlight from reaching the Earth’s surface, where it is needed by organisms—specifically plants—to carry out processes such as photosynthesis. Without sufficient sunlight, the energy transformation needed by these plants to survive cannot occur efficiently and effectively. This lack of sunlight disrupts not only plants in an ecosystem, but also food webs, as animals are unable to obtain energy from plants that cannot grow or prosper. The overexploitation of resources, such as overfishing and overhunting, disrupts the energy flow in existing ecosystems as well. By removing a large number of species from a given ecosystem, the balance of the food chain is disrupted. For example, if too many fish are hunted by humans, predators of these fish, such as hawks and other birds, are unable to eat them. These predators rely on energy from their prey to survive. If predators cannot obtain this energy, they will die, leading to a decrease in the population of the given predator species. This, in turn, will lead to an increase in the population of other organisms that the predators used to regulate. This fluctuation in population levels disrupts the energy flow between trophic levels. When one animal eats another, energy is transferred between trophic levels, with the predator gaining energy-rich molecules from the prey’s body. While these energy transfers may seem highly efficient, only about 10 percent of the energy from the previous trophic level is passed on to the next (BBC). In conclusion, urbanization and the overexploitation of resources can lead to disruptions in energy transfer.
To conclude, human activities such as deforestation, pollution, urbanization, and the overexploitation of resources can alter the way energy flows within an ecosystem. Deforestation involves the clearing of large areas of trees, making way for urbanization or resource extraction. Deforestation is detrimental to energy transfer within ecosystems because without sufficient trees to convert sunlight into chemical energy, other trophic levels are unable to obtain such energy. Urbanization is the process by which people move from rural areas to larger cities, increasing population density and replacing natural landscapes with concrete. These non-natural surfaces reflect more heat, which is radiated back into the atmosphere. Pollution, particularly air and water pollution, hinders the ability of aquatic and terrestrial organisms to perform photosynthesis and disrupts energy flow in ecosystems. Overuse of resources, such as overfishing, alters the functioning of food webs by removing essential prey species,
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