The separation of a substance into simpler substances or basic elements. Decomposition can be brought about by exposure to heat, light, or chemical or biological activity.
The process of breaking down organic material, such as dead plant or animal tissue, into smaller molecules that are available for use by the organisms of an ecosystem. Decomposition is carried on by bacteria, fungi, protists, worms, and certain other organisms.
Shown above is the definition of decomposition, and the goal of this page and the experiments of my classmates and I is to understand what decomposition really is on a deeper level. I will show you with evidence backed by the experiments we have done a model of decomposition analyzing many different factors that affect every part of the process.
My experiment analyzed one factor that affects the rate of decomposition, temperature. We took measures to make sure that all other factors were eliminated to show the full of affect of temperature on the rate of decomposition. We decided that we would compare the decomposition rates of 4 jars, 2 jars would be inside and 2 would be outside in the winter. One of each the outside and inside jars would be filled with a apple cut into fourths the other would be filled with an orange cut the same way. Each jar was covered the same way with a mesh covering the top allowing air to flow through but meant to keep out insects or any other solids. Over the course of the experiment the outside temperature started out at a high of 50 degrees and only proceeded to get colder as days went on. For the majority of the experiment the jars were kept anywhere from 0-20 degrees which is much lower than the freezing temperature of water. While the jars on the inside were kept at a constant 70 degrees were ran our experiment approximately from Dec 1st to Jan 6th.
A sample of our results are shown below:
Jar A: Oranges Inside
Jar B: Oranges Outside
Jar C: Apples Inside
Jar D: Apples Outside
Day 1 December 1:
Jar A- 494g
Jar B- 482g
Jar C- 508g
Jar D- 522g
Day 17:
Jar A- 458g
Jar B- 466g
Jar C- 434g
Jar D- 502g
Last Day Jan 6:
Jar A- 410g
Jar B- 464g
Jar C- 368g
Jar D- 500g
When looking at our data I was able to notice some profound trends, primarily that the jars that were outside in the freezing temperatures lost much less weight than the jars that were inside at room temperature. What this means is that temperature has a direct effect on the rate on decomposition in that the warmer it is the easier it is for bacteria to grow due to the fact that most bacteria do grow around 70 degrees. I have come to the conclusion that if the temperature is to cold for bacteria or fungi to form then the decomposition process is slowed and if kept at a consistently low temperature it may actually be stopped. However if the temperature is in a zone where bacteria can form they will grow where nutrients are available and the decomposition process will start. I believe temperature to be a primary factor due to the fact that disregarding all other factors if you lower the temperature below freezing then you can actually virtually stop the process of decomposition.
Another primary factor that has direct effects on decomposition is water, without the presence of water decomposition is not possible. This is due to the fact that the organisms that are responsible for decomposition (bacteria, fungi, ect.) all require water to survive. Therefore without water decomposition is not possible. This was well documented by a experiment done by another class in which they took 2 jars and filled each one with leaves and dirt. They put them both in the back of classroom which was at a constant 70 degrees. They planned to measure the effects of water on decomposition by adding water to one of the jars throughout the experiment.
There observations shown below:
Wet Jar:
White fuzzy mold formed
Water turned black and thick
Strong smell coming from the jar
Water absorbed fast
Leaves didn't seem to break down
Dry Jar:
Leaves didn't seem to decompose
No Smell
Dirt became dry and fine.
These observations show some clear evidence that without water decomposition is not possible. You can see that in the wet jar the experimenters clearly noted that white fuzzy mold formed and that a strong smell was coming from the jar. These are key marks of bacteria and mold growing similar to old leftovers in your fridge. While on the other hand the dry jar did not have similar results although it was in the same environment. They reported no mold, no smell, and stated that the leaves did not decompose. This is because of the lack of water. Without water the bacteria were unable to grow so they leaves were unable to be broken down. In comparison to the experiment above where decomposition did occur without the addition of water it was because of the fact that the fruit that the bacteria formed on has water in it. Even with the water trapped in the fruit cells the bacteria can still grow and use that water in the fruit to survive however when dealing with a dried up leaf and dry soil there is not enough moisture trapped for the bacteria to grow. Also in the case of the jars in my experiment that were kept outside the water in the fruits cells actually was frozen it was so cold outside. So using those observations as evidence I can draw the conclusion that water is necessary for decomposition because without it bacteria will not grow so therefore decomposition will not occur.
Nutrients can have a serious effects of the rate of decomposition without certain nutrients the organisms responsible for decomposition cannot live. The primary nutrient that effects decomposition is salt, due to the fact that the other nutrients required for bacteria to form are always found present in the organic matter that needs to be decomposed. The one necessary nutrient that is found in varying levels is salt because it is not present in high levels in plants because they don't need a lot of it to survive however decomposers do need it so if salt levels are low then the growth of decomposers is slowed. This is best illustrated by another experiment that was done in our classes. In this experiment they took 3 jars and put each in the same environment, 90g soil, 1 apple, open top, no light, room temp (70 degrees). The experimental factor was salt, in one jar they added no salt, in another they added 2g, and in the last they added 4g. The experiment was designed to see how varying levels of salt effected the rate of decomposition.
Their key observations:
Only jars with salt got mold
The more salt the faster decomposition
The more salt the more average weight lost per day
The observations prove a clear point that the level of salt positively effects the rate of decomposition. This is because with more salt present there is very little stopping the bacteria growth where as salt levels are usually low keeping decomposers in check slowing down the process. The experiment proves that if more salt is present than more life can be supported on the apple or whatever is being decomposed therefore leading to faster decomposition. In comparison to the other experiments this group did not report any mold on the jar without salt, I believe this is because the bacteria grew so fast on the other jars that the experiment was nearly complete before bacteria would be able to form on an apple with such low salt content. It is even more noticeable since they did not cut the apples at all in contrast to my experiment in which we cut ours into 1/4s, bacteria grew much quicker on ours because the skin of an apple is designed to not allow bacteria growth probably by being extremely low in salt and water content. While the fruit of the plant has much higher water and salt content so bacteria grew in my experiment.
In conclusion there are 3 primary factors that effect the rate of decomposition, temperature, and salt levels. These factors are interconnected and without any one factor decomposition is stopped or slowed. In the case of temperature if it is not a healthy level for bacteria then they will not grow and decomposition will not occur or be extremely slowed. Even if the temperature is in a proper zone if there is no water to support the life of decomposers then decomposition cannot occur. Finally salt levels effect the speed and the type of decomposition that is able to occur. Low levels will result in slower decomposition by mainly bacteria while higher levels can support more life leading to faster decomposition. So you can see that all three factors play important roles and all are needed for the process to be possible and each one effects how fast and in what ways things are broken down in ecosystems.
Modeling Decomposition
Decomposition-
Shown above is the definition of decomposition, and the goal of this page and the experiments of my classmates and I is to understand what decomposition really is on a deeper level. I will show you with evidence backed by the experiments we have done a model of decomposition analyzing many different factors that affect every part of the process.
My experiment analyzed one factor that affects the rate of decomposition, temperature. We took measures to make sure that all other factors were eliminated to show the full of affect of temperature on the rate of decomposition. We decided that we would compare the decomposition rates of 4 jars, 2 jars would be inside and 2 would be outside in the winter. One of each the outside and inside jars would be filled with a apple cut into fourths the other would be filled with an orange cut the same way. Each jar was covered the same way with a mesh covering the top allowing air to flow through but meant to keep out insects or any other solids. Over the course of the experiment the outside temperature started out at a high of 50 degrees and only proceeded to get colder as days went on. For the majority of the experiment the jars were kept anywhere from 0-20 degrees which is much lower than the freezing temperature of water. While the jars on the inside were kept at a constant 70 degrees were ran our experiment approximately from Dec 1st to Jan 6th.
A sample of our results are shown below:
Jar A: Oranges Inside
Jar B: Oranges Outside
Jar C: Apples Inside
Jar D: Apples Outside
Day 1 December 1:
Day 17:
Last Day Jan 6:
When looking at our data I was able to notice some profound trends, primarily that the jars that were outside in the freezing temperatures lost much less weight than the jars that were inside at room temperature. What this means is that temperature has a direct effect on the rate on decomposition in that the warmer it is the easier it is for bacteria to grow due to the fact that most bacteria do grow around 70 degrees. I have come to the conclusion that if the temperature is to cold for bacteria or fungi to form then the decomposition process is slowed and if kept at a consistently low temperature it may actually be stopped. However if the temperature is in a zone where bacteria can form they will grow where nutrients are available and the decomposition process will start. I believe temperature to be a primary factor due to the fact that disregarding all other factors if you lower the temperature below freezing then you can actually virtually stop the process of decomposition.
Another primary factor that has direct effects on decomposition is water, without the presence of water decomposition is not possible. This is due to the fact that the organisms that are responsible for decomposition (bacteria, fungi, ect.) all require water to survive. Therefore without water decomposition is not possible. This was well documented by a experiment done by another class in which they took 2 jars and filled each one with leaves and dirt. They put them both in the back of classroom which was at a constant 70 degrees. They planned to measure the effects of water on decomposition by adding water to one of the jars throughout the experiment.
There observations shown below:
Wet Jar:
Dry Jar:
These observations show some clear evidence that without water decomposition is not possible. You can see that in the wet jar the experimenters clearly noted that white fuzzy mold formed and that a strong smell was coming from the jar. These are key marks of bacteria and mold growing similar to old leftovers in your fridge. While on the other hand the dry jar did not have similar results although it was in the same environment. They reported no mold, no smell, and stated that the leaves did not decompose. This is because of the lack of water. Without water the bacteria were unable to grow so they leaves were unable to be broken down. In comparison to the experiment above where decomposition did occur without the addition of water it was because of the fact that the fruit that the bacteria formed on has water in it. Even with the water trapped in the fruit cells the bacteria can still grow and use that water in the fruit to survive however when dealing with a dried up leaf and dry soil there is not enough moisture trapped for the bacteria to grow. Also in the case of the jars in my experiment that were kept outside the water in the fruits cells actually was frozen it was so cold outside. So using those observations as evidence I can draw the conclusion that water is necessary for decomposition because without it bacteria will not grow so therefore decomposition will not occur.
Nutrients can have a serious effects of the rate of decomposition without certain nutrients the organisms responsible for decomposition cannot live. The primary nutrient that effects decomposition is salt, due to the fact that the other nutrients required for bacteria to form are always found present in the organic matter that needs to be decomposed. The one necessary nutrient that is found in varying levels is salt because it is not present in high levels in plants because they don't need a lot of it to survive however decomposers do need it so if salt levels are low then the growth of decomposers is slowed. This is best illustrated by another experiment that was done in our classes. In this experiment they took 3 jars and put each in the same environment, 90g soil, 1 apple, open top, no light, room temp (70 degrees). The experimental factor was salt, in one jar they added no salt, in another they added 2g, and in the last they added 4g. The experiment was designed to see how varying levels of salt effected the rate of decomposition.
Their key observations:
The observations prove a clear point that the level of salt positively effects the rate of decomposition. This is because with more salt present there is very little stopping the bacteria growth where as salt levels are usually low keeping decomposers in check slowing down the process. The experiment proves that if more salt is present than more life can be supported on the apple or whatever is being decomposed therefore leading to faster decomposition. In comparison to the other experiments this group did not report any mold on the jar without salt, I believe this is because the bacteria grew so fast on the other jars that the experiment was nearly complete before bacteria would be able to form on an apple with such low salt content. It is even more noticeable since they did not cut the apples at all in contrast to my experiment in which we cut ours into 1/4s, bacteria grew much quicker on ours because the skin of an apple is designed to not allow bacteria growth probably by being extremely low in salt and water content. While the fruit of the plant has much higher water and salt content so bacteria grew in my experiment.
In conclusion there are 3 primary factors that effect the rate of decomposition, temperature, and salt levels. These factors are interconnected and without any one factor decomposition is stopped or slowed. In the case of temperature if it is not a healthy level for bacteria then they will not grow and decomposition will not occur or be extremely slowed. Even if the temperature is in a proper zone if there is no water to support the life of decomposers then decomposition cannot occur. Finally salt levels effect the speed and the type of decomposition that is able to occur. Low levels will result in slower decomposition by mainly bacteria while higher levels can support more life leading to faster decomposition. So you can see that all three factors play important roles and all are needed for the process to be possible and each one effects how fast and in what ways things are broken down in ecosystems.