INTRODUCTION

The food chain is very important to the lives of humans because any one species needs the others in order to survive. If one species dies out because of something like pollution, it might break apart the food chain and affect humans. Daphnia are important because they reproduce quickly, which makes it hard for them to die off. They are near the bottom of the food chain, therefore supporting fish and other organisms. 
 

POLLUTION
Types
There are different types of pollution that occur almost anywhere.  First, there is water pollution, one of the most common kinds. There is also air and soil pollution.  Every single kind of pollution is dangerous and harmful to humans and wildlife.

Water Pollution
There are also specific types of water pollution.  All different chemicals and toxins have different effects on wildlife and human life.  There are many toxic chemicals that can harm living things like bleach, any kind of weed killer, oil, gasoline or antifreeze, de-icing road salt, and acid rain. 
Acid rain is a very dangerous pollutant.  It has many terrible effects on nature.  It kills aquatic plants, mammals, fish, and also is hazardous to humans. It can even lower the ability for fish like salmon and trout to reproduce.  Acid rain usually comes from big cities where there are large industries.  The smoke and smog in the air collects in a cloud, and then the wind blows it.  Then, when it rains, all of the pollution in the cloud comes down as acid in the water and kills wildlife. 

When oil spills into water, animals are killed from being coated in the thick, black liquid.  Birds get their feathers coated in oil, and can not fly, and it becomes hard for them to keep water out of their feathers. Also, when oil coats aquatic animals, they become trapped and cannot move.  They will eventually die unless rescued by humans.

Fertilizers and sewage are also very deadly if they spill into water and contaminate it.  They cause something called eutrophication.  Eutrophication is an explosive growth of microorganisms and algae that uses up all of the oxygen in a body of water.  This causes fish to die because of oxygen loss. The food chain could break because of this problem, affecting water mammals.

Air Pollution
The gasses that form acid rain are also a type of air pollution.  It is toxic to humans, animals, and plants when it is in the air too.  When animals breathe in air in an area that is polluted, their lungs can be harmed or they could get sick if exposed to it for a very long time.  That’s why many big cities (like Los Angeles) have so much pollution and smoke in the air.  Automobiles also pollute the air with their exhaust.  This all gathers in the air to create pollution or smog.
 

Solution
People can prevent water pollution by just making sure that they don’t leave toxins lying around where they could leak into a storm drain.  This could pollute water.  Also littering, dumping, and polluting into water is a way people pollute a river, lake, stream, or ocean.  So not doing this is an easy way to keep water clean. 
Water conservation is a way to save water.  Using a little less water for everything could save some for the future. 
 

DAPHNIA

Crustaceans 
Crustaceans are marine creatures that usually have a shell of some sort.  There are many different kinds of crustaceans.  The whole crustacean group is one of many in the arthropod family.  Some other groups in the arthropod family are millipedes, centipedes, insects, and spiders or arachnids.  Even crustaceans are broken down into a couple of groups, the large ones and the small ones.  Some of the small ones are daphnia, brine shrimp, and fairy shrimp.  All of these are very small and somewhat difficult to see with the human eye.  The other group, the large crustaceans, consists of sow bugs, crayfish, and even lobster and crabs.  These are highly visible to humans, and lobster and crab are eaten for food.
 

Daphnia Facts
Daphnia are microorganisms that live in water.  Their heart and all of their insides are visible because of a clear, transparent shell.  They have branched out arms and antennae that they filter food with.  After it is filtered, it is sent to the mouth where it is swallowed.  A daphnia's eye is very large and sensitive to light.  Daphnia live in almost any still water area, whether it's a pond or a lake.  Their predators are mostly bigger aquatic creatures.  Even some small fish eat daphnia, on an occasion of little food.  Daphnia eat things like bacteria and algae.  The algae that grows in a fish tank or aquarium is perfect food for a daphnia to eat.  Baccius Coli is a type of bacteria that is favored by daphnia.  It is completely microscopic.  Daphnia also eat protozoa, euglena, and chilomonas.

There are a few different types of daphnia including Daphnia magna and Daphnia pulex.  Magna are usually about four millimeters long and visible to the naked eye.  Pulex are visible, but are very hard to see and are usually observed with a microscope or magnifying glass. To move through the water, daphnia sink down, then flick their arms and bounce up towards the surface.  They don’t exactly swim, but just "bounce".
Daphnia and most other crustaceans reproduce very quickly.  Some specific daphnia species can have 13 billion descendants in 60 days.  This makes it hard for them to become extinct, and therefore the food chain would normally be stable. 
 

THE FOOD CHAIN

Both daphnia and pollution have much to do with the food chain.  All species in the food chain depend on each other for their own survival.  For example, if one species at the bottom of the food chain dies out, then the whole thing is affected.  When toxins pollute water, they may kill a small organism at the bottom of the food chain.  When they die off, the animals that eat them can’t and so they might die off too.  This could keep on going until it affects humans if no one stops the pollution problem.  People have to know that these things are possible so that they can help to prevent it.
 
 

SUMMARY

Water pollution, and all other kinds of pollution, are very serious and dangerous.  They could harm and even kill all kinds of wildlife, plants, and even humans.  The food chain is important because every single creature and organism depends on each other to survive.  When pollution kills a whole species, all of the animals up the food chain are affected.

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