Understanding Matter Flows in Ecosystems

This movie covers Subtopic 2.3 Part 2, Flows of Matter, under the main topic of IBESS Topic 2, Ecosystems and Ecology. Topic 2.3 Part 1 covers Flows of Energy. The significant idea for this subtopic is that ecosystems are linked together by energy and matter flows. We are focusing in this movie on the flows of matter. Matter flows through ecosystems. Matter includes nutrients. There are about 40 elements that cycle through ecosystems, though some exist in trace amounts. Oxygen, carbon dioxide, and water also flow through ecosystems. The big difference between energy and matter flow is that energy flows in one direction through an ecosystem, starting with solar radiation and finally leaving as heat through respiration. However, Chemical nutrients in the biosphere cycle. Nutrients are absorbed by organisms from the soil and atmosphere and circulate through trophic levels and are finally released back into the ecosystem, usually via the decomposers. These cycles are biogeochemical cycles. Matter can be identified as inputs and outputs in all organisms. Matter may change form, but... Unlike energy, it does not degrade. Recollect that as you move up trophic levels, the quality of energy decreases, but not with matter. Matter is stored in long and short-term chemical forms. Let's take a moment to focus on the carbon cycle and nitrogen cycle. The carbon and nitrogen cycles are used to illustrate the flow of matter. using flow diagrams. These cycles contain storages, sometimes referred to as sinks, and flows which move matter between the storages. Keep in mind that there are many biogeochemical cycles occurring on Earth, not just the carbon and nitrogen cycles, but that's what we're focusing on in this movie. In the carbon cycle, stores are found in both organic and inorganic forms. Organisms on land and in the waters, including plants and forests, are an organic storage of carbon, as are fossilized life forms and fossil fuels. When fossil fuels are replaced by inorganic molecules, they become an inorganic store of carbon. Sedimentary rocks are locked up or fixed carbon stores. In the oceans, where carbon is dissolved or locked up as carbonates in the shells of marine organisms, we find additional stores of inorganic carbon. Flows in the carbon cycle include the process of carbon being fixed during photosynthesis. This is called carbon fixation. The release of carbon from the process of respiration and the release of carbon through combustion. These processes cause carbon to circulate through living and non-living systems within the ecosystem. There is a finite amount of carbon on Earth, and we have a rough idea of where it goes. We also have an idea of how human activity impacts the carbon cycle. The burning of fossil fuels, the making of cement, and land use changes such as deforestation all result in additional carbon dioxide entering the atmosphere. This can be offset by photosynthesis and by absorption of CO2 by the oceans, but these offsets do not... compensate our activities. There is a net annual increase of carbon into the atmosphere through carbon dioxide. Notice the units. GTC stands for gigatons of carbon, and these numbers represent gigatons of carbon per year. Like I mentioned, we have a pretty good idea where carbon is stored and flows on Earth. We also know that human activity, such as Burning for clearing land, modern agricultural techniques, and the burning of fossil fuels alters the carbon cycle by increasing the flow of carbon into the atmosphere in the form of carbon dioxide. Furthermore, decreased land biota, as indicated here, or decreased plants and forests will result in less carbon being able to be removed from the atmosphere via photosynthesis. This is a positive feedback mechanism at work. Notice again the units for carbon. A gigaton of carbon is 1 billion megametric tons of carbon. Pause the video and study the diagram to gain a sense of the relative amounts of carbon and where they are found on Earth. Also be fully aware of the human impact on this biogeochemical cycle. Nitrogen is an essential element in proteins and DNA. Therefore, all living organisms need nitrogen. Nitrogen is arguably the most important nutrient in regulating primary productivity and species diversity in both aquatic and terrestrial systems, which is why we are discussing the nitrogen cycle. Nitrogen sinks include organisms, the soil, fossil fuels, the atmosphere, and water. Flows in the nitrogen cycle include nitrogen fixation, nitrification, nitrite assimilation, ammonification, denitrification, as well as feeding, excretion, death, and decomposition. We're going to talk more about these aspects of the nitrogen cycle. For plants to take up nitrogen, it must be in the form of ammonium or nitrate ions. Animals eat plants. and so take in their nitrogen in the form of amino acids and nucleotides. The nitrogen cycle is made up of five major steps. Nitrogen fixation, nitrification, nitrate assimilation, ammonification, and denitrification. Step one of the nitrogen cycle is nitrogen fixation. When atmospheric nitrogen is made available to plants through the fixation of atmospheric nitrogen. This can occur in several ways. Biological nitrogen fixation includes nitrogen-fixing bacteria living free in the soil, nitrogen-fixing bacteria living symbiolically in the root nodules of legumes. The plant provides bacteria with sugars from photosynthesis, and the bacteria provide the plant with nitrates. And cyanobacteria. also known as blue-green algae, that live in soil or water. These bacteria are the cause of the high productivity of Asian rice fields, many of which have been productive for hundreds or even thousands of years without nitrogen-containing fertilizers. So these contribute to biological nitrogen fixation. Also, lightning and volcanic eruptions cause the oxidation of nitrogen gas to nitrate. which is then washed into the soil, and by the industrial Haber process, which is a nitrogen fixing process used to make fertilizer. Nitrogen and hydrogen gases are combined under pressure in the presence of iron as a catalyst to form ammonia. Step two of the nitrogen cycle is nitrification. the process in which nitrifying bacteria convert ammonia, ammonium, to nitrite, while others convert the nitrites to nitrates, which are then available to be absorbed by the plant roots. Step 3 in the nitrogen cycle, assimilation. Once living organisms have taken in the nitrogen, they assimilate it, or build it into more complex molecules. Protein synthesis in cells turns inorganic nitrogen compounds into more complex amino acids, and then these join to form proteins. The nucleotides are the building blocks of DNA, and these also contain nitrogen. Step four in the nitrogen cycle, ammonification. Decom, as a plant or animal decays. decomposers such as insects, worms, bacteria, or fungi will decompose organic materials to produce ammonia and ammonium ions. This process is known as ammonification and releases ammonium ions into the soil which can be absorbed by the plants. Step five in the nitrogen cycle, denitrification. Bacteria convert ammonium, nitrate, and nitrite ions to nitrogen gas which escapes to the atmosphere. Like with the carbon cycle, humans also impact the nitrogen cycle burning fossil fuels. The application of nitrogen-based fertilizers and other activities can dramatically increase the amount of biologically available nitrogen in the ecosystem. And because nitrogen availability often limits the primary productivity of many ecosystems, large changes in availability of nitrogen can lead to severe alterations of the nitrogen cycle in both aquatic and terrestrial ecosystems. When people remove animals, or plants for food for humans. They extract nitrogen from the cycle. Much of this nitrogen is later lost to the sea in human sewage. In terrestrial ecosystems, the addition of nitrogen can lead to nutrient imbalance in trees and change in forest health and declines in biodiversity. With increased nitrogen availability, there is often a change in carbon storage. thus impacting more processes than just the nitrogen cycle. In agricultural systems, fertilizers are used extensively to increase plant production, but unused nitrogen, usually in the form of nitrate, can leach into the soil, enter streams, rivers, lakes, and the sea, and can lead to eutrophication. The process of making synthetic fertilizers for use in agriculture by the Haber process has increased significantly over the past year. past several decades. In fact, today nearly 80% of the nitrogen found in human tissues originated from the Haber process. Planting leguminous crops will enrich the soil with nitrogen as well. Soil condition also affects the nitrogen cycle. If it becomes waterlogged near the surface, most bacteria are unable to break down the dead material. One more note on eutrophication. Much of the nitrogen applied to agricultural and urban areas ultimately enters rivers, lakes, and the sea, and the near-shore coastal systems. In near-shore coastal marine systems, increases in nitrogen can often lead to anoxia, no oxygen, or hypoxia, low oxygen, altered biodiversity, and changes in the food web structure. as well as general habitat degradation. The significant idea number two of this subtopic is that the sun's energy drives flows of energy and matter, and humans are impacting the flows of energy and matter both locally and globally. We've discussed the impact of humans on the carbon and nitrogen cycles in this movie. Since this movie is focusing on the flow of matter, Let's briefly look at how the sun's energy drives the flow of matter. The sun provides energy for the process of photosynthesis, which drives the carbon cycle. And the nitrogen cycle is strongly affected by photosynthetic processes as well, in a number of ways. Plants are an integral part of the nitrogen cycle. Plants take up nitrogen in the form of nitrite, ammonium items, or nitrate ions. This nitrogen is released back into the environment when they die. Plants' capacity to incorporate the nitrogen is obviously affected by its growth and health, something for which photosynthesis is directly responsible. Also, a number of nitrifying bacteria that convert ammonia to nitrate and then nitrate are aerobic and require the presence of oxygen for functioning. This oxygen is provided by the photosynthetic process. which maintains the level of oxygen in our ecosphere. Here is a summary of this subtopic. Between topic 2.3 movies part 1 and part 2, you should feel comfortable with all of these ideas, skills, and knowledge statements. This ends the movie for IBESS topic 2.3 part 2, Flows of Matter, under the main topic of IBESS topic 2, Ecology and Ecosystems. Topic 2.3, Part 1, covers flows of energy. The slides are created by me, Dr. Nina Markham. Images are courtesy of Creative Commons unless otherwise indicated with a citation under the image. If all images on a slide are from the same source, the source simply appears under the bottom of the slide. Other resources for you include your IBESS textbook, whether in hardback form or online, such as Cognity. Thank you for listening.

We are focusing in this movie on the flows of matter. Matter flows through ecosystems. Matter includes nutrients.

There are about 40 elements that cycle through ecosystems, though some exist in trace amounts. Oxygen, carbon dioxide, and water also flow through ecosystems. The big difference between energy and matter flow is that energy flows in one direction through an ecosystem, starting with solar radiation and finally leaving as heat through respiration. However, Chemical nutrients in the biosphere cycle.

Nutrients are absorbed by organisms from the soil and atmosphere and circulate through trophic levels and are finally released back into the ecosystem, usually via the decomposers. These cycles are biogeochemical cycles. Matter can be identified as inputs and outputs in all organisms. Matter may change form, but...

Unlike energy, it does not degrade. Recollect that as you move up trophic levels, the quality of energy decreases, but not with matter. Matter is stored in long and short-term chemical forms.

Let's take a moment to focus on the carbon cycle and nitrogen cycle. The carbon and nitrogen cycles are used to illustrate the flow of matter. using flow diagrams. These cycles contain storages, sometimes referred to as sinks, and flows which move matter between the storages. Keep in mind that there are many biogeochemical cycles occurring on Earth, not just the carbon and nitrogen cycles, but that's what we're focusing on in this movie.

In the carbon cycle, stores are found in both organic and inorganic forms. Organisms on land and in the waters, including plants and forests, are an organic storage of carbon, as are fossilized life forms and fossil fuels. When fossil fuels are replaced by inorganic molecules, they become an inorganic store of carbon.

Sedimentary rocks are locked up or fixed carbon stores. In the oceans, where carbon is dissolved or locked up as carbonates in the shells of marine organisms, we find additional stores of inorganic carbon. Flows in the carbon cycle include the process of carbon being fixed during photosynthesis. This is called carbon fixation. The release of carbon from the process of respiration and the release of carbon through combustion.

These processes cause carbon to circulate through living and non-living systems within the ecosystem. There is a finite amount of carbon on Earth, and we have a rough idea of where it goes. We also have an idea of how human activity impacts the carbon cycle.

The burning of fossil fuels, the making of cement, and land use changes such as deforestation all result in additional carbon dioxide entering the atmosphere. This can be offset by photosynthesis and by absorption of CO2 by the oceans, but these offsets do not... compensate our activities.

There is a net annual increase of carbon into the atmosphere through carbon dioxide. Notice the units. GTC stands for gigatons of carbon, and these numbers represent gigatons of carbon per year. Like I mentioned, we have a pretty good idea where carbon is stored and flows on Earth. We also know that human activity, such as Burning for clearing land, modern agricultural techniques, and the burning of fossil fuels alters the carbon cycle by increasing the flow of carbon into the atmosphere in the form of carbon dioxide.

Furthermore, decreased land biota, as indicated here, or decreased plants and forests will result in less carbon being able to be removed from the atmosphere via photosynthesis. This is a positive feedback mechanism at work. Notice again the units for carbon. A gigaton of carbon is 1 billion megametric tons of carbon. Pause the video and study the diagram to gain a sense of the relative amounts of carbon and where they are found on Earth.

Also be fully aware of the human impact on this biogeochemical cycle. Nitrogen is an essential element in proteins and DNA. Therefore, all living organisms need nitrogen.

Nitrogen is arguably the most important nutrient in regulating primary productivity and species diversity in both aquatic and terrestrial systems, which is why we are discussing the nitrogen cycle. Nitrogen sinks include organisms, the soil, fossil fuels, the atmosphere, and water. Flows in the nitrogen cycle include nitrogen fixation, nitrification, nitrite assimilation, ammonification, denitrification, as well as feeding, excretion, death, and decomposition. We're going to talk more about these aspects of the nitrogen cycle.

For plants to take up nitrogen, it must be in the form of ammonium or nitrate ions. Animals eat plants. and so take in their nitrogen in the form of amino acids and nucleotides.

The nitrogen cycle is made up of five major steps. Nitrogen fixation, nitrification, nitrate assimilation, ammonification, and denitrification. Step one of the nitrogen cycle is nitrogen fixation. When atmospheric nitrogen is made available to plants through the fixation of atmospheric nitrogen.

This can occur in several ways. Biological nitrogen fixation includes nitrogen-fixing bacteria living free in the soil, nitrogen-fixing bacteria living symbiolically in the root nodules of legumes. The plant provides bacteria with sugars from photosynthesis, and the bacteria provide the plant with nitrates. And cyanobacteria.

also known as blue-green algae, that live in soil or water. These bacteria are the cause of the high productivity of Asian rice fields, many of which have been productive for hundreds or even thousands of years without nitrogen-containing fertilizers. So these contribute to biological nitrogen fixation.

Also, lightning and volcanic eruptions cause the oxidation of nitrogen gas to nitrate. which is then washed into the soil, and by the industrial Haber process, which is a nitrogen fixing process used to make fertilizer. Nitrogen and hydrogen gases are combined under pressure in the presence of iron as a catalyst to form ammonia.

Step two of the nitrogen cycle is nitrification. the process in which nitrifying bacteria convert ammonia, ammonium, to nitrite, while others convert the nitrites to nitrates, which are then available to be absorbed by the plant roots. Step 3 in the nitrogen cycle, assimilation.

Once living organisms have taken in the nitrogen, they assimilate it, or build it into more complex molecules. Protein synthesis in cells turns inorganic nitrogen compounds into more complex amino acids, and then these join to form proteins. The nucleotides are the building blocks of DNA, and these also contain nitrogen.

Step four in the nitrogen cycle, ammonification. Decom, as a plant or animal decays. decomposers such as insects, worms, bacteria, or fungi will decompose organic materials to produce ammonia and ammonium ions.

This process is known as ammonification and releases ammonium ions into the soil which can be absorbed by the plants. Step five in the nitrogen cycle, denitrification. Bacteria convert ammonium, nitrate, and nitrite ions to nitrogen gas which escapes to the atmosphere. Like with the carbon cycle, humans also impact the nitrogen cycle burning fossil fuels. The application of nitrogen-based fertilizers and other activities can dramatically increase the amount of biologically available nitrogen in the ecosystem.

And because nitrogen availability often limits the primary productivity of many ecosystems, large changes in availability of nitrogen can lead to severe alterations of the nitrogen cycle in both aquatic and terrestrial ecosystems. When people remove animals, or plants for food for humans. They extract nitrogen from the cycle.

Much of this nitrogen is later lost to the sea in human sewage. In terrestrial ecosystems, the addition of nitrogen can lead to nutrient imbalance in trees and change in forest health and declines in biodiversity. With increased nitrogen availability, there is often a change in carbon storage. thus impacting more processes than just the nitrogen cycle.

In agricultural systems, fertilizers are used extensively to increase plant production, but unused nitrogen, usually in the form of nitrate, can leach into the soil, enter streams, rivers, lakes, and the sea, and can lead to eutrophication. The process of making synthetic fertilizers for use in agriculture by the Haber process has increased significantly over the past year. past several decades. In fact, today nearly 80% of the nitrogen found in human tissues originated from the Haber process.

Planting leguminous crops will enrich the soil with nitrogen as well. Soil condition also affects the nitrogen cycle. If it becomes waterlogged near the surface, most bacteria are unable to break down the dead material.

One more note on eutrophication. Much of the nitrogen applied to agricultural and urban areas ultimately enters rivers, lakes, and the sea, and the near-shore coastal systems. In near-shore coastal marine systems, increases in nitrogen can often lead to anoxia, no oxygen, or hypoxia, low oxygen, altered biodiversity, and changes in the food web structure. as well as general habitat degradation. The significant idea number two of this subtopic is that the sun's energy drives flows of energy and matter, and humans are impacting the flows of energy and matter both locally and globally.

We've discussed the impact of humans on the carbon and nitrogen cycles in this movie. Since this movie is focusing on the flow of matter, Let's briefly look at how the sun's energy drives the flow of matter. The sun provides energy for the process of photosynthesis, which drives the carbon cycle.

And the nitrogen cycle is strongly affected by photosynthetic processes as well, in a number of ways. Plants are an integral part of the nitrogen cycle. Plants take up nitrogen in the form of nitrite, ammonium items, or nitrate ions. This nitrogen is released back into the environment when they die.

Plants' capacity to incorporate the nitrogen is obviously affected by its growth and health, something for which photosynthesis is directly responsible. Also, a number of nitrifying bacteria that convert ammonia to nitrate and then nitrate are aerobic and require the presence of oxygen for functioning. This oxygen is provided by the photosynthetic process.

which maintains the level of oxygen in our ecosphere. Here is a summary of this subtopic. Between topic 2.3 movies part 1 and part 2, you should feel comfortable with all of these ideas, skills, and knowledge statements. This ends the movie for IBESS topic 2.3 part 2, Flows of Matter, under the main topic of IBESS topic 2, Ecology and Ecosystems. Topic 2.3, Part 1, covers flows of energy.

The slides are created by me, Dr. Nina Markham. Images are courtesy of Creative Commons unless otherwise indicated with a citation under the image. If all images on a slide are from the same source, the source simply appears under the bottom of the slide.

Other resources for you include your IBESS textbook, whether in hardback form or online, such as Cognity. Thank you for listening.

Transcript for:Understanding Matter Flows in Ecosystems

Transcript for:
Understanding Matter Flows in Ecosystems