The Phosphorus Cycle

okay so in this video we're going to look at the phosphorous cycle now one thing I want to mention is that even though phosphorous cycles through the environment there is no phosphorous in the atmosphere so it's not like the carbon cycle where there's carbon dioxide in the atmosphere it's not like the nitrogen cycle where there's nitrogen in the atmosphere the phosphorous cycle begins with rocks and we're going to go through that in just a moment well first of all why do we need phosphorous well phosphorous if you recall is one of the one of the atoms that makes up the molecule called ATP adenosine triphosphate in the picture here here's a mitochondria and through the process of cellular respiration the mitochondria will make this molecule adenosine triphosphate you can see there are peas for phosphorus in the diagram another important molecule that that requires phosphorus is DNA and not just DNA but RNAi nucleic acids so here's a double helix now if we if we look at the molecular structure of DNA remember that DNA is made from small parts called nucleotides and you can see the nucleotide is a sugar molecule nitrogen base and then a P the P stands for a phosphate molecule the reason it's called phosphate is there's phosphorus in it and one nucleotide combined with another with another with another like you see in the picture makes up DNA a nucleic acid so DNA the genetic heredity the genetic molecule of life requires phosphorus and a third reason why phosphorus is really important in the animation here we have a phospholipid bilayer basically we have the cell membrane of all of our cells phospholipid phospho implies there's phosphorus in the lipids that make up the cell membrane well let's go ahead and get on in to the stages of the cycle now so here we have on a rain cloud and it's raining and so what we're going to show you is really the first stage of the phosphorous cycle and it comes from the breaking down in the weathering of rocks you know rocks are just lumps of minerals and one of the minerals that rocks are commonly made from is phosphorous and so when it rains phosphorus little chips of rocks break off and crack and crumble and this is what we mean by the weathering of rocks and so phosphorous is released as rocks weather and break down and erode and the phosphorous has now entered the soil well once the phosphorous is in the soil now it becomes pretty straightforward the flowers representing their producers in this animation will absorb the phosphorous through their roots and once the phosphorous is in the roots of plants I hope you can figure out how animals can obtain the phosphorous so now that the phosphorus is in the plants the phosphorus simply moves up the food chain in our animation we have phosphorus going from the flowers to the snail well that's because stales eat leaves and flowers and plants in the next part of the animation we have phosphorus going from the snail into the frog well that's because frogs can eat snails phosphorus is simply moving up the food chain and then we come to area four represented by our mushrooms in the animation it says decomposers will obtain phosphorus as they feed on dead remains in the animation there's a peak coming from the flowers there's a pea coming from the snail and there's a pea coming from the frog and they're all going to the mushrooms representing the decomposers I'm not implying that mushrooms hunt frogs and snails and flowers but when frogs and snails and flowers die they're dead remains which still contain phosphorous are fed on by default or such as fungus decomposers such as bacteria well if we notice here also there is a pee coming out of the mushroom because again all organisms give off waste and fungus and other decomposers will give off phosphorous in their waste and so if you just pause and look at the animation we have a cycle here we have a continuous loop of phosphorous throughout the ecosystem throughout the environment well there's one little twist I want to add to this before the video is finished we have to focus on the human contribution to the phosphorus cycle so humans will often use fertilizers and phosphorus is a very common ingredient as well as nitrogen phosphorus and nitrogen are very common to fertilizers well we add fertilizers to help our crops and plants grow better and so here we have a picture of a farmer using a tractor and pulling a trailer that is dispensing fertilizers over their crops and so the problem with this is that the phosphorus when it's sprayed on the crops will often run off with rain into bodies of water so in this picture right here you can see that water is running off of this farm and so often the fertilizers are simply being carried away with this rain water here so in my animation here here we have a farmer adding peas a bunch of peas for phosphorus so the farmers adding phosphorus to their crops to the plants and so their fertilize the farm is fertilizing the crops well unfortunately the phosphorus that's accumulating in the animation won't just stay there often the phosphorus is carried with weather and rain so when it rains when it rains often the phosphorus is simply carried downstream or downriver down down the slope of the land and you can see in the animation the phosphorus is accumulating in this body of water well this is going to lead to another problem this often causes what are called algal blooms an extreme growth of algae in the animation you see the water in the pond is turning green because of all the algae that is now being stimulated to grow from all the phosphorus phosphorus is a fertilizer it stimulates the growth of algae as well as stimulating the growth of crops well why is this bad well first of all before we address why is that bad here's a couple photographs of algal blooms you can see this watery area is just as a layer of green slime growing on it and here we have a lake or a river that's completely been turned green because of the extreme growth of algae well what the problem that this causes is something called eutrophication off often and ultimately what happens to this little body of water it becomes a dead zone the algae is so dense and so thick it will often block sunlight to plants that live deeper in the water and they start to die often oh the next step that happens is the algae themselves will begin to die and bacteria will feed on the dead remains of the algae well the bacteria are using all of the oxygen in the water to break down and decompose the algae that the the water almost becomes action oxygen lists becomes void of oxygen because the bacteria are using it all so therefore snails die fish die organism other animals that live in this water begin to die because there's no oxygen the extreme growth of algae often causes the pH of the rivers and the lakes to change and so that's another reason why the lake can become a dead zone so the point is is that the phosphorus cycles out of balance and you know human contributions are some of the reasons for that so if you're if you have a bit of a green thumb at home and you're interested in landscaping and gardening you know perhaps you can go down to you know the local supply store and look for safer non-chemical ways to perhaps fertilize your lawn and fertilize your garden so here we go that was the there we go that was the phosphorous cycle go ahead and pause this video it's a very quick practice quiz then the video was pretty quick so go ahead and pause the video answer these questions if you're in my class I'd be happy to check them for accuracy before school or after school good luck

Channel: Beverly Biology

Views: 225,869

Rating: 4.796371 out of 5

Keywords: Phosphorus (Chemical Element), Phosphorus Cycle, Biology (Media Genre), Biogeochemical cycle, Rocks, Fertilizers, Run off, eutrophication

Id: c5KqwhX1dvk

Length: 8min 53sec (533 seconds)

Published: Wed Jun 18 2014