For which chemicals are biogeochemical cycles global? Explain.

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Accepted Answer

Hello everyone. Let's look at our next problem. It says all the bio geochemical cycles involve atmospheric components. Except so we're looking for the one bio geochemical cycle that doesn't have a gaseous component in the atmosphere. So when we look at our answer choices we see we have a phosphorus cycle. The nitrogen cycle sea water cycle and d carbon cycle. Well the phosphorus cycle is one that maybe we're not often as familiar with. Um Whereas the other three are ones that we often study a lot in biology so we can kind of quickly eliminate the last three as having well known atmospheric components. The nitrogen cycle you do have gaseous nitrogen and two in the atmosphere. Um It gets taken up by nitrogen fixing bacteria. Um And then can be taken up into plants and then animals and then denied certification is done by de nitro flying bacteria in the soil and they release nitrogen back into the atmosphere. So the nitrogen cycle definitely has an atmospheric component. So it's not our answer choice. See the water cycle obviously we have water vapor in the air that forms clouds, rains, carries on the water cycle but definitely an atmospheric component to that. And finally choice D. The carbon cycle. While we have carbon dioxide C. 02 as our atmospheric component. Very large part of the atmosphere breathed out by animals. And then of course the C. 02 taken in by plants in photosynthesis and fixed into organic molecules. So carbon cycle also atmospheric component. So we're left with the phosphorus cycle choice a as our correct answer and the reason it does not have a gaseous component. Um An atmospheric component is that phosphorus is solid at normal temperature and pressure. Um It's a major sort of reservoir on earth is in sedimentary rock. And I'm just gonna put up a diagram of the phosphorus cycle since many of us are a little less familiar with it than some of these, the other three and we can see where it is. Um phosphorus is present as inorganic phosphates in the soil. Um They get taken up by plants and incorporate into organic compounds. The plants are eaten by animals. Phosphorus is obviously really crucial to life on earth. It's part of D. N. A. R N. A N. A. T. P. We need it to function. Um So again the plants take it up incorporating organic compounds, animals eat it and then through manure or after death decomposition um the phosphorus and animal tissues goes back into the soil, where the bacteria break it down to inorganic phosphates. Um There's the organic phosphates and soil and sediment also can, due to weathering, erosion, can runoff into water and in water. We also have a cycle where we have some inorganic phosphates being taken up by things like algae and then consumed by animals in the ocean. My little fish here and then again the same process of manure and decomposition returning into the soil and sediment. Um And the other thing is that humans affect this a lot by this process here. Um The phosphorus cycle will eventually lead to a decrease of phosphorus in the soil um because phosphorus moves very rapidly through plants and animals, but it moves very, very slowly through the geographical, you know, through sediment and through soil and over time. So as a result, the rapid processing through plants and animals will gradually decrease the amount of phosphorus available to them. Well, humans deal with this by mining phosphorus, making fertilizer and then adding phosphorus to the soils. But some of that fertilizer is going to run off from the soil as well and kind of throw some more phosphorus in here. Um So good to know that also there's the fact that humans are mining phosphorus in one place, manufacturing into fertilizer and shipping at all different places around the world adds to that phosphate phosphorus movement around the earth. So humans have a big, big impact on this phosphorus cycle. But again, there is no atmospheric component to choice. A the phosphorus cycle. See you in the next video

For which chemicals are biogeochemical cycles global? Explain.

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Key Concepts

Biogeochemical Cycles

Global Chemicals

Human Impact on Cycles