[Music] hi it's Mr Anderson and this is environmental science video 11 it's on biogeochemical cycles this is a picture of George Rose you've probably never seen him before but you may have seen his work if you've ever seen a giant kinetic sculpture at a museum where billiard balls are lifted up and then they move down again he invented that and has installed lots of those around the world here's a planning document in this one he's trying to show how energy from the Sun or within the Earth can drive things like the water cycle and the
rock cycle and it's a really good model for how nutrients move around on our planet the carbon and the nitrogen that we have is set and it just moves around between the living and non-living world and so the matter on our planet is conserved we have a set amount and it moves between the biotic or living an abiotic world the living world is called the biosphere on our planet and the nutrients that we need are best remembered in this pneumonic schnaps carbon hydrogen nitrogen oxygen phosphorus and sulfur if we look at the abiotic factors that's
going to be the atmosphere lithosphere and hydrosphere and so these biogeochemical cycles is going to be how the nutrients move between the living and non-living now why is it such a long word bio Geo and chemical are the biological chemical and geological processes by which the nutrients move around you're probably most familiar with the water cycle we'll start there then talk about the carbon cycle and following that the nitrogen cycle one thing you're probably not familiar with with the nitrogen cycle is the importance of bacteria and how they can nitrogen fix or take nitrogen out
of the atmosphere and put it into the living world we'll then move to the phosphorus one of the lowest the slowest turning Cycles it involves Rock but no atmosphere now both nitrogen and phosphorus are what are called limiting nutrients that means life really needs them and it's waiting for them and once it gets those nutrients then it grows really really quickly that's a good thing but sometimes can lead to urif and then finally we'll finish with the sulfur cycle and so the energy on our planet remember starts in the sun moves through producers to Consumers
other consumers and eventually is lost as heat but as we move to matter everything on the planet is conserved there's no sun anymore and so how do the producers get the nutrients that they need it's from their environment from the atmosphere from the hydrosphere from the lithosphere how do consumers get the matter they need by eating plants or eating consumers that ate plants how does the matter go back into the environment again through these biogeochemical cycles and so what are the nutrients that life needs what are the billiard balls of life well a good pneumonic
is schnaps carbon hydrogen nitrogen oxygen phosphorus and sulfur if we organize that into the five Cycles we've got the water cycle carbon cycle nitrogen cycle phosphorus cycle and sulfur cycle so why do we need all of this matter we're filled with water we also used the oxygen to release energy and transfer energy with the hydrogen we're built out of macro molecules that's what carbon is the building block of the nitrogen and the sulfur are both big components in the proteins that make us up and then the phosphorus is found in DNA RNA and the ATP
and so if we don't have these nutrients if we don't have these atoms then life can't exist so we need to pull them out of our environment so let's start with a water cycle how do plants get water they're going to take it in through their Roots what about a cow they're simply going to drink the water but how does it move through the abiotic parts of our planet first of all we're going to have evaporation off Ocean Lakes and streams and then we're going to have evapotranspiration so it's evaporating but also it's being transpired
through the leaves of a plant it's now moving from a liquid to a gas what eventually happens is we're going to have condensation in the clouds we have precipitation and then we have runoff over the surface and through groundwater and the whole thing begins again if we start with carbon how does a plant get carbon it's going to be through photosynthesis both in plants on land and then phytoplankton that are going to be found in the ocean what about an an animal like this cow it simply gets the carbon through its diet it eats the
plant or if something eats a cow like you it's take you're taking the carbon from the meat of the cow so what happens to that carbon it's eventually released through cellular respiration goes back into the atmosphere again as carbon dioxide so a lot of that carbon is going to be in the atmosphere as carbon dioxide now we can also take that carbon and it can be covered by Rock and we can create coal and oil fossil fuels so we're storing that carbon in the Rock we can extract It Again by digging a well and then
we can have combustion where a factory releases that carbon dioxide back into to the atmosphere and the whole cycle continues again the nitrogen cycle is a little different most of the nitrogen is going to be found in the atmosphere as nitrogen gas and to get it into the living systems we have to do nitrogen fixation so there are bacteria that live lots of times on the roots of plant in these nodules and they're converting the nitrogen in the atmosphere into usable ammonia we can also put ammonia on our Fields as fertilizer and then it's going
to be a similat in other words plants are going to take it in through their roots and we are going to get it from Plants simply by eating them now how does get returned back to the atmosphere it's kind of complex what happens is we have death we then have Decay and so bacteria or fungi are going to convert that nitrogen into ammonium and then we have other bacteria nitrify bacteria that are going to convert that ammonium into nitrites and then nitrates now the nitrates can be leech they can move into the water supply of
our planet remember nitrogen is a limiting nutrient plants life is just waiting for nitrogen to be there and once we get nitrogen for example in this stream you'll get an algae bloom we'll get a bunch of algae growing really really quickly now that seems like a good thing but all those algae are going to quickly die and nutrification is this process by which they die and then other bacteria have to break them down through respiration and it consumes all of the oxygen so it's not healthy for that water supply but let's keep watching the nitrogen
how does it get back into the atmosphere we'll have denitrify bacteria that are going to return it back into the atmosphere and so the whole thing can begin again now the phosphorus cycle is going to turn more slowly it starts by having rock that have phosphorus being uplifted we then have weathering and erosion and that's going to move the phosphorus into the soil into the water supply we could also add fertilizers that's going to have phosphorus and the whole thing since it's limiting can promote urif foration what happens to the phosphorus we then have a
similation where it's taken into plants we can eat the plants and we get it what eventually happens is we die so through excretion and Decay we return that phosphorus into the water supply it eventually Works its way to the ocean and then it eventually settles out in these sediments and so it never goes to the atmosphere it becomes part of these phosphate rocks which are then uplifted again and so it takes a long time for this cycle to turn because we don't include the atmosphere and then finally we have the sulfur cycle sulfur cycle is
going to move from the oceans the sulfur we have bacteria that are going to convert that into dimethyl sulfide which eventually becomes sulfur oxide or sulfur dioxide we can also in increase sulfur dioxide through volcanism so volcanoes are releasing hydrogen sulfide which becomes sulfur dioxide and then factories are going to release sulfur dioxide as well it's in the atmosphere now how does it get back to the planet it's going to rain down as sulfuric acid and sulfates we can then assimilate that take it into the living material same way into plants and then into consumers
and finally it works its way back through the water supply and now it's going to be sulfur in the oceans so the cycle could continue again but we can also have that rock cycle forming some of that into fossil fuels which can be extracted again and the cycle continues and so for each of these Cycles you should be able to figure out how to plants get it how to animals get it and then how does it recycle back through the atmosphere hydrosphere and lithosphere so did you learn the following could you pause the video right
now and fill in the blanks remember matter is conserved on our planet we have a set amount it moves through the biotic and a biotic spheres a good way to remember the nutrients we need is schnaps the biogeochemical cycles are how we move it through abiotic and biotic it's the water cycle carbon cycle nitrogen cycle which requires nitrogen fixation remember nitrogen and phosphorus are limiting nutrients which can lead to urif foration the last cycle is the sulfur cycle and I hope that was helpful [Music] n
