CTM. Tipos de contaminantes - Contenido educativo
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Good morning.
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Today we are going to talk, on the one hand, about the pollutants that can affect water,
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the different types of pollutants there are, and, on the other hand, a type of pollution
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that affects surface waters, such as sewage.
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We start with the types of pollutants.
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We can make a division based on the characteristics of those pollutants and thus we can divide them
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into physical, chemical or biological pollutants.
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Within the physical pollutants, which do we have?
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We have, on the one hand, water.
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Water is going to be used as a coolant in the machines of the companies that generate
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any type of product.
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When we have an engine that is running, it is going to produce friction, it is going to produce
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heat due to that normal operation, and we have to cool it down if we don't want
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that engine to break down.
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How do we do it with water?
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The water that comes in from the surface water is cold water and comes out with a certain
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temperature.
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What can cause us to pour it directly into rivers or into the sea?
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On the one hand, it reduces the amount of dissolved oxygen because hot water contains
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less dissolved oxygen than cold water.
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What causes this, that the amount of dissolved oxygen is reduced?
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On the one hand, certain species are extinguished with certain temperature limits.
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If a fish has to lay its eggs at 10 or 15 degrees, if suddenly the water is 20 or 25,
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it will not be able to lay its eggs, it will even get sick and die.
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This can also cause other species to appear, which can be invasive species that are from
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other places, but it is good that they are adapted to that temperature range.
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Then certain species that should not be there begin to proliferate.
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Growth cycles can also vary, or that those animals, those plants, become abnormally
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small or abnormally large, with certain consequences that can have, that is, that suddenly
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they become super predators instead of predators and that they eat everything that appears out there.
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An abnormal reproduction, for example, salmonids, trout, salmon, when they change
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the temperature of the water, their reproduction is very affected, because they are fish that
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are very sensitive to different temperature variations.
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Radioactive particles can also appear, generally derived from nuclear power plants.
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Also hospitals, for example, hospital waste, usually have radioactive particles, because
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if they see us, they are going to do a x-ray, those x-rays are deriving from some place
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that ends up being water and can end up being incorporated into the water that is released into the river,
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that is released into the sea.
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Also a natural radiation derived from rocks, such as plutonium, which emit a series of
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radioactive particles.
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What effects do they have?
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They can accumulate in mud, that is, those radioactive particles from the water pass to the mud,
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and with the consequences that this entails, they can end up in organisms and generate mutations.
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Inhalation by radon is also very important.
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Radon appears mainly naturally in plutonic rocks and it is convenient in houses that are
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located in areas where there are this type of rocks, for example in the Sierra de Madrid
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there is a lot, or in other types of mountainous systems that are made of granite, it is convenient
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to ventilate the houses a lot because radon accumulates in the houses, it can end up in the water
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and we can end up ingesting them and it gives lung cancer problems.
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Solids in suspension, well, from the residual waters, the erosion of the soil, infiltrations
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cause an increase in turbidity, which implies an increase in turbidity, a decrease in photosynthesis.
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If the water is turbid, all the organisms that are below that do the photosynthesis
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will not be able to do it.
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With this, there is also an alteration of the trophic chains, because we eliminate the primary producers.
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It can also cause mobility and breathing difficulties, let's remember that there are many organisms
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that live underwater and that move and breathe underwater, so if the water is full of
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substances in suspension, it will be very difficult for them to breathe.
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It is the same as if we get in the middle of a sandstorm, it would be very difficult to breathe.
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Modification of water properties, here we talk about smell and taste.
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If instead of opening the tap and a completely transparent water comes out, it starts to have
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a brownish tone, well, it doesn't give us much confidence.
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Within chemical pollutants, we are going to distinguish between organic, inorganic and gas pollutants.
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Let's start with the organic ones, here we have, on the one hand, carbohydrates and proteins,
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which usually come from waste water, from a house, it always ends up in the water,
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in a certain part of the food we eat, that food that we eat will end up in the sea.
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Fats, we have industrial waste, even the fat from our kitchen, when we wash a pan,
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that fat will go through the sink and end up in a deporator, which if it is not filtered well,
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it ends up in the river, or even there are many people who still throw the oil used by the sink,
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which pollutes a lot, I tell you, and there are containers to deposit it.
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It can also appear in pesticides and phenols, because they are simply substances that are used
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in conventional agriculture, in chemical agriculture, to prevent weeds from growing.
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They are quite harmful as endocrine disruptors.
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Let's see, among the effects that chemical pollutants can have,
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on the one hand, are the odors, that of bad odor and bad taste in water,
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and on the other hand, those endocrine disruptors.
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I have posted a video in the virtual lab that explains this topic of endocrine disruptors,
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so you can see it now.
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Let's move on to inorganic pollutants.
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Here we have several types, on the one hand, we have the alteration of pH,
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the vertices can be acidic, they can be basic, they can have neutral pH,
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and that will modify the pH of the water.
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Where does it come from? It can be both industrial and domestic.
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For example, when we use bleach to clean, which now with the issue of COVID is quite common,
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it has a very basic pH. When water is poured, the water will be modified to that basic pH.
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The salts. Where do the salts come from? They can come from a domestic use,
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the salt, for example, that we use for washing dishes, or a marine intrusion.
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How does a marine intrusion occur?
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Let's imagine that we are close to the coast and we are extracting fresh water from an underground aquifer.
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That underground aquifer, as it is close to sea water,
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it may happen that if we extract water, the sea water enters the aquifer
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and that causes a contamination of salt and the aquifer becomes unsuitable for consumption.
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What does it cause? The salinization of an aquifer or it can also cause increased hardness.
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Water, I don't know if you know, but it can have different degrees of hardness.
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For example, in Madrid the water is soft because we are close to the mountains
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where we extract the water and the soil, because of its characteristics,
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because of which the rivers that reach Madrid flow, it does not provide much calcium carbonate,
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which is what gives it that hardness, but if we are located, for example, in Almería or Alicante or Tarragona,
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those waters will have a lot of hardness because the rivers, throughout their journey,
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will make a contribution of calcium carbonate and will increase the hardness of the water.
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This can cause washing machines to break down due to that increase in lime.
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Heavy metals. The industry often uses heavy metals or are residues that are produced in the industry.
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These can cause bioaccumulation, which is good because in living beings,
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as we go up in the trophic chain, there are more and more of those heavy metals.
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I have posted another video on the virtual egg so you can see what bioaccumulation is and the problems it generates.
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More chemical and inorganic pollutants. We have nitrogen derivatives.
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Remember that nitrogen was also a basic component of life,
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with which animal and agricultural remains can generate an excess of nitrogen in the soil.
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This can cause eutrophication, which we are going to see today,
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or that a series of toxic nitrates appear.
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In fact, nitrates are the main source of underground water pollution,
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because of those nitrates that are added to agriculture.
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Phosphorus derivatives.
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Detergents, so that they can clean more and leave the clothes white and shiny,
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have a lot of phosphorus.
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That phosphorus facilitates the eutrophication processes.
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We are going to explain what eutrophication is inside NADO, so I won't go into it anymore.
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And sulfur, which can have a domestic or industrial use, has a purging effect.
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Gases. What gases can we find?
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Yes, in the water we have many dissolved gases too.
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Among them, hydrogen sulfide and methane can be domestic or appear as infiltrations
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and cause a smell and taste in the water that are not desirable.
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Biological pollutants.
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There can be biological pollutants.
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It may be strange to think that water has something more than water and some salts,
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but in most countries in the world, water is not totally sterile,
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but the tap water has a lot of living or dead organisms that we can ingest.
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In addition, there may be areas where, due to their characteristics,
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one type of organism or another proliferates more and it can cause problems or not.
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Bacteria can appear.
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For example, cholera is a problem even in areas where water is potable.
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Imagine that here the water is potable, but due to some problem,
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imagine that there is an earthquake, that there is a hurricane,
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that there is a storm called Philomena,
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the tap water is cut off.
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Notice that in Texas it happened two days ago.
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I'm not talking about anything strange.
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And this potable water, people need to drink it.
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Where does the water come from?
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Many times, in certain places, people go to rivers,
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to areas where there are natural sources, to extract the water.
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If the water is not well treated, it can contain bacteria.
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Like cholera, which can cause a lot of problems.
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There may also be viruses.
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Most viruses do not resist well in water, so we do not worry much about them.
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Protozoa. Parasitic protozoa are very annoying, I tell you.
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And parasitic worms.
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If you remember, when you were little, they told you,
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if you bite your nails, intestinal worms can enter you.
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Well, yes, they can appear.
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And many of them can appear in large quantities.
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Most of us have intestinal worms and we do not find out.
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In general, nothing happens.
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But hey, they can be unpleasant.
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I have posted a video on the subject of cholera,
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because I tell you that it seems like something that will never affect us,
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but it could affect us, or even if we travel to third countries.
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Let's talk now about a type of contamination of surface waters.
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In this case, eutrophication.
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Definition.
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Well, eutrophication is the increase in primary productivity,
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algae, oceans, bacteria,
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caused by the introduction of bio-nutrients,
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with nitrogen and phosphorus,
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through agricultural and livestock vertices.
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What happens so that there is eutrophication?
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First, we have to have waters that are stagnant,
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or that have a very slow course.
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That is, eutrophication can occur in lakes, lagoons, reservoirs,
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very dry seas.
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In rivers that are running, it cannot occur,
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because there is no other option.
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The water is very oxygenated,
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and these types of processes do not appear.
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How do they occur?
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Let's imagine a lake in which animals live peacefully,
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plants in happy company,
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and an increase in phosphorus and nitrogen occurs.
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Be careful, this increase can be natural.
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It may be a time when there is a lot of production,
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for example, imagine in summer,
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when lakes decrease their volume a lot,
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because a lot of water evaporates,
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and that, in addition,
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the plants are full doing photosynthesis,
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and an increase in phosphorus and nitrogen occurs.
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But what we study,
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precisely as anthropogenic contamination,
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this increase in phosphorus and nitrogen,
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is generally due to all those agricultural activities,
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which use a lot of phosphorus and nitrogen for their chemical fertilizers,
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or from households,
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it can also occur because the detergents we use have phosphorus,
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and a continuous flow is produced to areas where it is a little oxygenated,
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this increase can occur.
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Ok, increase in phosphorus and nitrogen.
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Who are the first to grow?
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The first to grow are phytoplankton.
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This phytoplankton is made up of diatoms,
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then chlorophyces can also appear,
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which is a type of algae,
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and cyanophyces, another type of algae.
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What happens when phytoplankton grows?
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Basically, the surface of the water becomes cloudy.
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Of course, they grow a lot, a lot, a lot,
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and prevent the sunlight from reaching the lower layers of that lake.
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There is a lot of oxygen that goes to the atmosphere.
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Yes, it is very good, there is a lot of oxygen in the atmosphere,
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but all the lower layers of that phytoplankton will not get sunlight.
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What happens over time?
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The vegetation that is below that phytoplankton begins to die.
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When it dies, the organic matter accumulates in the bottom.
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Remember that these are areas where there is very little oxygenation,
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so if oxygen cannot reach the bottom,
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because the oxygen of the phytoplankton, which is at the top,
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goes to the atmosphere, but does not go to the water.
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In addition, the bacteria that are in the bottom consume that organic matter,
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decreasing oxygen more and more,
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with which, in the end, all the animals end up dying
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due to lack of oxygen,
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and an area is produced that we call anoxic,
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that there is no oxygen in that area.
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In that area there would be a large amount of hydrogen sulfide,
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methane, ammonia, which produces a terrible smell.
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It smells like rotten eggs.
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What solution is there for this?
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Basically, an oxygenation.
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First, stop pouring, obviously,
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and then try not to go further,
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causing an oxygenation of the area.
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It is complicated depending on the size,
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but if we can control those pourings,
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we will surely get the ecosystem to recover.
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A variant of eutrophication in the sea would be red tides.
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It is similar to eutrophication, but it occurs in the sea,
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and a phytoplankton eclosion occurs with toxins.
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They are generally bacteria that have that reddish color
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because they have carotenoids,
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and they cause toxicity in the water.
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Many species die.
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In certain areas they appear more or less frequently.
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Red tides have been recorded for thousands of years.
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Since the beginning of writing, red tides have been recorded in the seas.
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But what happens if we have a sea with an excess of phosphates
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and an excess of nitrogen?
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Those red tides will be favored to occur more frequently.
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And so far today's class.
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With this we finish.
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I have also posted a video about eutrophication in the smaller sea,
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which I hope you find interesting.
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Until the next day.
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- Idioma/s:
- Autor/es:
- Marta García Pérez
- Subido por:
- Marta G.
- Licencia:
- Reconocimiento - No comercial - Sin obra derivada
- Visualizaciones:
- 21
- Fecha:
- 25 de febrero de 2023 - 18:56
- Visibilidad:
- Clave
- Centro:
- Sin centro asignado
- Duración:
- 17′ 27″
- Relación de aspecto:
- 1.78:1
- Resolución:
- 960x540 píxeles
- Tamaño:
- 75.50 MBytes