In bodies of water there exist different levels as you start from the surface and proceed downward. We will be looking into the community in one of the deepest, the benthos community.
Both freshwater and oceanic bodies of water have similar zones, with some minor differences.
They all have a top photosynthetic community where alga live and thrive and some mid-ranged zones. They have them labeled with different names but are very similar in what interactions and living things exist here. One of the zones that is the same in both types of water is the benthic zone.
The benthic zone is the bottom-most layer of aquatic zones. What this zone appears like will ultimately depend on what type of benthic zone we are talking about. If you are describing a shallow lake, the benthic zone will still receive ample amounts of light.
If you are talking about the oceanic benthic zone, then you will see little to no light here.If you have a deeper benthic zone, you will also experience lower oxygen levels and the possibility of increased pressure. Imagine for a minute if you were in a pool and dove down to the deeper end of the pool going all the way to the bottom. Now this might only be 8-12 feet deep but you can feel the pressure increase on you as you go deeper. Amplify that by a lot as you are going hundreds and possibly thousands of feet down in an oceanic benthic zone.
What is the Benthos?
The term benthos is used to describe the bottom most layer of aquatic zones, and also includes the sand, silt, and organisms found there. In the benthos you can expect to find organisms from each kingdom.
Some live above the sediment, hyperbenthos, some live just on top of the sediment, epibenthos, and some live actually in the sediment, endobenthos.The benthos can also be divided into three separate categories depending upon size of the organism. Macrobenthos organisms include ones that can be seen with the naked eye. This includes crabs, lobsters, mussels, etc… In the meiobenthos division we see organisms that are less than a millimeter but larger than 0.
10 mm. Nematodes would be seen here. Finally we would have the microbenthos. Those would include single-celled organisms such as diatoms and amoebas.
Organisms in the hyperbenthos would be most typical looking fish as they swim about as well as any other organism that swims. The epibenthos is home to most of the organisms that do not move or swim and stay in one place, such as sea cucumbers. In the endobenthos, organisms that burrow under the sediment will live, such as a sand dollar.The type of organisms living in the benthos will vary, as mentioned before, with regards to pressure, depth, oxygen content, and temperature. In benthos zones that are in coastal waters, you will find more photosynthetic organisms as well as just more organisms in general. In deeper oceanic benthos, you will find very little in comparison to coastal benthos zones.
In the deeper benthos you will see organisms that are adapted for extremely cold temperatures as well as high amounts of pressure. Many of the organisms here will lack pigmentation and will look downright scary. This is because there is very little or no light that penetrates the sheer blackness that is the norm here.
To recap, benthic zones are found in all bodies of water, because this term refers to the bottom layer of water in a body of water. Benthos refers to the bottom layer of water and all the organisms that live in it.
There are different layers where organisms live in the benthos; in the sediment (hyperbenthos), on top of the sediment (epibenthos), and in the sediment (endobenthos). There are also different organisms that live in these layers; macrobenthos or large organisms, meiobenthos or smaller but still distinguishable organisms, and finally microbenthos, those too small to see without the aid of a microscope.