Decomposition+Rates

Decomposition Rates DONT FORGET TO LOOK AT THE IMAGES AT THE BOTTOM! toc
 * Watershed Project- Decomposition**, Pedro Andrade, Colin Fisk, William Greenbaum

=Introduction =

= =

In the study of garbage decomposition, the following questions come to mind.

**Question**s
Which materials decompose the fastest, natural objects, food, or synthetic materials? How long does each take? Will any of these things decompose faster in an open area as opposed to a more enclosed area?

**Hypothesis**
We expect because it is rather common knowledge that the natural objects will decompose the fastest, in about 3 months, followed by the food about 5 months, followed by the synthetic materials which will decompose so slowly that it is negligible. We also expect the items to decompose faster in the open area than in the closed area, because they will be more open to the elements and sunlight, which will encourage growth.

**Applications**
We hope this information will help determine how to make the most efficient decomposition piles. The results should tell us which items decompose the fastest, and therefore which are preferable to decompose instead of alternative methods of waste disposal. Also, what conditions objects decompose fastest in, we can learn where to place the decomposition piles so that they are most efficient. The biggest purpose of this experiment is to be able to see decomposition of the 3 categories in different situations in a lengthy window of time.

 =Methods and Materials=

**Materials**
Chicken wire – wrapped around the frames to create the cages Wood planks – used to create the frames of the cages Nails and staples – used to put the cages together Hammer – nail the frame together Saw – cut the wood to the correct dimensions Staple gun – staple the chicken wire to the frame Scale – to mass the garbage Plastic bags – to put the garbage into to mass it Types of garbage: Fruit Plastics Natural (sticks and leaves and grass)

**Procedure**
The first thing one must do in this experiment is construct two cages with three chambers. These chambers or cells must contain enough room to include about 300-1000 grams of leaves, fruit, or everyday garbage products (glass, foil, plastic). The dimensions can vary from about a yard to five feet long and about a foot and a half wide. The tallness is about a foot and a half as well. Each chamber should have about a foot to foot and half in length so that each item can be evenly spread. The wood should be pieced together by nails. The purpose of this is to juxtapose the different decomposition by keeping the items very close to each other but not letting them touch.

The way this is accomplished is by chicken wire. The wire will not let bigger items cross over, and it keeps out the animals from coming in to eat the fruit from the cage. The chicken wire should be wrapped around the entire cage, but do not forget to first put chicken wire in between each of the chambers to separate the garbage. Be careful when wrapping the chicken wire as it can easily cut through skin, and be mindful to fold in the edges when finished to avoid potentially injuring animals that want to attempt to enter the cage. Strong staples attach the chicken wire.

Our goal with this setup was to simulate someone throwing trash or litter into the woods. For example, if someone was hiking along a trail and finishes a soda, what happens if that person throws their bottle into different places in the woods? Same for food. Will it decompose faster in a field as oppose to a densely wooded area. We just used the sticks and leaves as a control group.

**Instructions**
The finished result should be a big, heavy cage that can be used to easily watch the decomposition of the three items we wish to observe. The wire should be opened at the top (wherever that is considered) and the fruit, leaves/twigs, and synthetic material should be placed just over the soil (it is advised to clear the ground of any leaves or rocks so that the objects have direct contact with the soil). Do not dig a hole and place the objects within because it will be impossible to find and weigh all the products. The bottom of the cage is covered by chicken wire so that if the cage is flipped, the garbage is not spread all over the floor. Unfortunately, that means that the objects do not have complete contact with the soil but at least the contents are safe from being thrown all over the floor of the woods. The cages should be placed in two areas: a clear area without trees looming over the cage and a wooded area with trees surrounding and above the cage. Do not forget to come back periodically to take pictures and record observations. When the garbage is finally to be collected and weighted, do not forget to bring a garbage bag to make sure you collect your trash.

Locations
__Cleared spot__ 040° 52.448’ N 073° 57.924’ W Elevation: 391ft __Wooded spot__ 040° 52.410’ N 073° 58.003’ W Elevation: 362ft 

Calender of work

 * December **


went to Flat Rock Brook to attempt and build a cage out of old wood and old nails that were stuck into the wood. Unfortunately the nails were too old and weak to use and they would not effectively connect the wood together. We could not build the cage after two hours of attempts to make it work. However, we refused to let the wood go to waste.

 

 **January**


Colin and Will went through the arduous process of building the first cage out of old wood. Colin and his father built one out of new wood and fashioned chicken wire around it. Will and Colin went to Flat Rock to construct another, Pedro (I) was not present because of scheduling and distance difficulties. They left the cages there finished with chicken wire and all. We were all happy. Also, Will picked out a clearing to place our cage in. He built a stick teepee that lasted through March (no picture sadly).

**February**


Colin and I (Pedro) went to Flat Rock again to put the cages and went to buy fresh fruit to put into the cage. I collected garbage over two weeks to put into the cage that was juice boxes, wrappers, glass, cans, and all the synthetic materials I could think of to put inside. We bought six grapefruits and decided to put 3 in each separate cage. We collected sticks and leaves from around the floor to put into each cage. We opened the cage with pliers and closed them carefully making sure to bend in sharp edges so the little ones do not get hurt. All items were weighed carefully.  <span style="color: rgb(0, 51, 0)">**March**

<span style="color: rgb(0, 51, 0)">
<span style="color: rgb(0, 51, 0)">the month where we let the objects rot.

<span style="color: rgb(0, 51, 0)"> **April**

<span style="color: rgb(0, 51, 0)">
<span style="color: rgb(0, 51, 0)">Will went to flat rock again to take pictures and see ho <span style="color: rgb(0, 51, 0)">w the environment has changed and how the items are decomposing. He noted the grapefruits lost their lively color and took pictures of the surrounding area. The clearing was beginning to be green again just like the woods.

<span style="color: rgb(0, 51, 0)">**May**

<span style="color: rgb(0, 51, 0)">
<span style="color: rgb(0, 51, 0)">Will and I went to Flat rock to finish up the project. We collected and weighed all the items on a box. We zeroed the box on the scale. We made some very amazing discoveries that will be revealed soon enough! Colin was sleeping peacefully in his abode. Will was injured by thorns. We brought in the cages. <span style="color: rgb(0, 51, 0); display: none"> <span style="color: rgb(0, 51, 0); display: none"> =Results=

Weights of all the objects

**Initial**
Wooded area Fruit - 1086 G Garbage - 363 G Leaves/twigs - 300 G

Cleared area Fruit - 1071 G Garbage - 297 G Leaves/twigs - 315 G

Weight of all the objects

**Final**
Woods Fruit – 439g Garbage -392g Leaves/Twigs – 221g

“Cleared Area” Fruit – 390g Garbage – 311g Leaves/Twigs -360g <span style="color: rgb(0, 51, 0); display: none">

<span style="color: rgb(0, 51, 0)">
<span style="color: rgb(0, 51, 0)"> For the wooded area- The cage rusted in the parts where the fruit touched because of the acid that came from the grapefruit. Grapefruit was rotted and soft and the grapefruit had some of its smell lingering (citric) Some garbage lost its coloring. Leaves were crumbly and black and sticks were soft. When the fruit was opened, we found our little friends the MAGGOTS!

<span style="color: rgb(0, 51, 0)">For the “cleared area”- Want to know why I keep saying “cleared” area? Because it was no longer clear when we visited in May! The area was literally overgrown in ferns and bushes, it was astonishing. The cage was barely visible in all the green! We had to pull the cage out of the area because ferns had literally grown all over it.

Juice boxes lost their color, leaves were crumbly, grapefruit partially decomposed and a lot mushier and softer than the wooded area, grapefruit had fungus on it, g<span style="color: rgb(0, 51, 0)">rapefruits lost a lot of the smell, when the fruit was opened it was black inside and had maggots and fungus as well.

It is nice to note that the garbage and enclosures did not greatly hinder growth in those areas. In the cleared area, plants had no trouble growing around or THROUGH our project. This could contribute to some experimental error, but we are not sure how.

<span style="color: rgb(0, 51, 0)">

<span style="color: rgb(0, 51, 0)">
<span style="color: rgb(0, 51, 0)">Wooded area: Grapefruit lost 647g or -59.6% Garbage gained 29g or +7.99% Leaves lost 79g or -26.33%

<span style="color: rgb(0, 51, 0)">“Clear area”: Grapefruit lost 681g or -63.6% Garbage gained 14g or +4.7% Leaves gain 45g or +14.3% <span style="color: rgb(0, 51, 0); display: none">

=External Research=

There is a lot of interesting research out there about decomposition rates, especially now during the search for greener methods and products. For instance, Daniel Burd, a high school student from Canada, isolated a combination of bacteria that can breakdown plastic bags in an estimated 3 months. (see [|news article]) Previously, we had thought that none of the garbage would decompose with the possible exception of the paper towels or napkins (chemicals in them might slow it down significantly).

Also, Jill Irvin, a professor at Ohio State University, said that fruit have chemical processes that continue to happen after being picked that we call ripening. So, most of the loss in mass in the fruit could be attributed to internal breakdown rather than external causes like weather and microbes.

Lastly, there were many in-depth studies on the decomposition rates of leaves. One study conclusively “simulated and observed [that] mass losses were higher in warm, moist environments (both forests) than in cold (tundra) or dry sites (desert), and simulated and observed [that] decay was more rapid for Drypetes than Triticum.” We may be able to apply that to our experiment by saying that the cleared area was subject to more precipitation and higher temperatures. In that case, our results agree with this conclusion. The Drypete and Triticum parts refer to litter quality, or the Nitrogen to lignin ratio. Nitrogen is a key chemical in decomposition and is the focus of the Nitrogen cycle. Thus, more Nitrogen creates a higher ratio, higher quality litter, and higher decomposition rate. Conversely, lignin is typically the last part of plant matter to decompose, and having more creates low quality litter that decomposes slower. So, if we could compare the quality of each material, we could predict which would decompose first. Working from previous knowledge, we assume that there is neither much nitrogen nor lignin in plastics or cans. The grapefruit probably has a decent amount of nitrogen. But since nitrogen is mainly present in amino acids and proteins, and we assume that grapefruits are mostly carbohydrates, there cannot be too much nitrogen. As for leaves, we expect that overall there is a higher percentage of lignin, but also a much higher percentage of nitrogen. So, leaves and twigs probably have the highest litter quality and should decompose the fastest as we hypothesized. Interesting note: these researchers also had some trouble with their methods and predictions, and found that they over and underestimated several outcomes.

Another study reinforced those findings by saying decomposition rates “tended to decrease with latitude (LAT) and lignin content (LIGN) of litter but increased with temperature, precipitation and nutrient concentrations at the large spatial scale.” Also, their “results indicate[d] that litter quality is the most important direct regulator of litter **<span style="background: white none repeat scroll 0% 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-weight: normal">decomposition ** at the global scale.” The study also “revealed significant relationships between litter **<span style="background: white none repeat scroll 0% 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-weight: normal">decomposition ** **<span style="background: white none repeat scroll 0% 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-weight: normal">rates ** and the combination of climatic factor and litter quality.” So, our hypothesis about weather being a factor was right. However, we could be interpreting this wrong because both cages were in the same climate region, even if they were in different micro-habitats.

=Conclusions=

<span style="color: rgb(0, 51, 0)"> <span style="color: rgb(0, 51, 0)">Results from the pure mass loss are as follows- The clearing had more loss in mass in grapefruit than the wooded area. The garbage gained mass overall because its decomposition was stagnant and leaves and twigs inevitably got into the garbage and were difficult to remove. The leaves lost a lot of mass in the wooded area because they were isolated and had good contact with the soil, maybe they fell out of the cage. The leaves in the clearing gain mass.

<span style="color: rgb(0, 51, 0)">The grapefruit decomposed quickly as expected. The leaves and twigs took <span style="color: rgb(0, 51, 0)">longer than we expected, and had they been buried I think they would have decomposed much faster. The garbage we saw only lost some coloring that was on the carton or plastic, and gained more mass overall in the project, which was due to experimental error (leaves and dirt entering the trash etc).

<span style="color: rgb(0, 51, 0)">The biggest decomposition rate is seen in the grapefruit and was easily weighed. The grapefruit was not separated and was just laid onto the cage’s bottom. This made it a lot easier to pick up and weigh than the leaves and twigs or the trash. The big difficulty with weighing the leaves and trash was getting all the units placed months ago into once place and being able to weigh it. We always believed there would be an issue w <span style="color: rgb(0, 51, 0)">ith leaves falling in and out of the cage, and that is what made this project the hardest to be accurate. <span style="color: rgb(0, 51, 0); display: none"> <span style="color: rgb(0, 51, 0)"> Sources of error include animals, natural occurrences like precipitation and snowing, bugs eating or taking away the food, people moving the cages out of their proper spots, and of course weighing errors. The hardest task of this project was isolation of the three categories to see their decomposition. We were able to see which items decomposed the most but it was difficult to catch this in the weight of the objects. This is because there are so many possible sources of error that are difficult to avoid because of our limited materials. Another source of error is the moisture in the objects before and after the project. Water plays a big factor in determining the weight of many of these objects, and we found paper towels full of water that were dry before. It would have been better if we first dried the objects first and then placed them, and then removed them and dried them again before massing each time. This would have eliminated most of the wet factor in the weight. All in all, net gain in mass meant that there was definitely error, but the other observation prove that the experiment is not totally inaccurate. A portion of our error came from weather. While attempting to recreate the circumstances of litter, we did not want to change the materials by purposely drying or moving them. However, this caused problems when it rained. If materials were wet, they would obviously weigh more and balance out the decomposed mass. When taking our final readings, we tried to wait a few days after the last rainfall, but some things were still wet. We attribute the gained weight to rain water.

This, however, leads to a new hypothesis. We believe the cleared area would be wetter because it was less shielded by trees and plants from rain. Thus, it would be wetter and weigh more within a week after rainfall. This appeared to be true with the leaves and stick. The leaves and sticks in the cleared area gained weight from water whereas the leaves in the wooded area were not nearly as wet. The difference between the two changes, 114g, seems too large however. So we also attribute the abnormally large loss in mass in the wooded area to the error that someone moved the cage. Some bits and pieces probably fell out that made it appear as if it decomposed more.

Strangely, the unnatural litter in both areas gained mass. Again, we think that was solely due to water and that there was not enough decomposition to counteract the gained mass. In addition, the results disagree with our hypothesis because the garbage in the cleared area gained LESS mass than the garbage in the wooded area. We think this was due to the nature of the garbage. Since the garbage was not exactly the same in both areas, there was probably more absorbent materials like paper towels in the wooded area that held water than in the cleared area. Thus, the wooded garbage was hit less with rain, it retained more water and in turn weighed more.

For the grapefruit, they are the least absorbent so they should have given the most reliable information.

To address our starting questions, the grapefruit decayed the fastest. However, this could be due to internal ripening instead of decaying. Depending on one's definition, those two could be the same thing. After the fruit, the leaves and sticks decayed the second fastest, followed by the garbage. As for location, we determined that, whatever the reason, materials in an open, unshielded area decompose faster than similar materials in a more protected or closed-off environment.

<span style="color: rgb(0, 51, 0)"> Two ecological implications are simple, fruits and leaves decompose more quickly than the items that we use every day. It is better for the environment to recycle and reuse these materials than to dump them into the forest and injure the animals around. The clearing had a drastic change since its time in the winter, showin <span style="color: rgb(0, 51, 0)">g just how drastically nature can change the results of an experiment. We wish we could have had better tools to easily measure the weight changes of our objects better, but overall we were happy that we were able to an extent witnes <span style="color: rgb(0, 51, 0)">s the de <span style="color: rgb(0, 51, 0)">c <span style="color: rgb(0, 51, 0)">omposition of these materials (which was our goal).

=Future Research=

= = We would expand our observation to include pH of soil, temperature, humidity, and rain fall at different locations to try to focus on the factors that most affect decomposition.

We would also try more than two locations, and perhaps one indoors as an extreme control.

Lastly, we would look more into “litter quality”, and see if those guidelines apply to materials other than wood and plant matter. Is this true for other natural materials and foods, or even genetically modified foods?

=Related images=

<span style="color: rgb(0, 51, 0)"> These two images show the wintery scene and the cage is hard to see in the first picture so Will provided with a cage close up. [|feb_20_clearing.JPG] [|cage_clearing_feb_20.JPG] These two images are of the cage and grapefruit in out in the clearing. <span style="color: rgb(0, 51, 0)"> [|april_4_clearing.JPG] [|april_4_grapefruit_clearing.JPG] These next two pictures are of the clearing overgrown with ferns, we were amazed. We had to pull it out of there. <span style="color: rgb(0, 51, 0)">[|cage_in_the_clearing.JPG] <span style="color: rgb(0, 51, 0)">[|cage_out_of_the_clearing.JPG] <span style="color: rgb(0, 51, 0)"> This is the picture of the woods cage, notice it is very near to trees. Will finally found it. <span style="color: rgb(0, 51, 0)">[|april_4_woods.JPG]

These next 4 images show the cage in the woods in may, notice the green next to Will. We weighed the contents of the woods cage. <span style="color: rgb(0, 51, 0)">[|cage_opened_in_woods.JPG] [|garbage_in_the_woods.JPG] [|weighing_wood_in_the_woods.JPG] [|grapefuit_in_the_woods.JPG]

These two images show the faded coloring of the artificial stuff. We found this to be kind of "cool". <span style="color: rgb(0, 51, 0)">[|faded_coloring_two.JPG] [|faded_coloring.JPG] <span style="color: rgb(0, 51, 0)"> These are not for the people easily disgusted. Will and I decided to dissect the grapefruit and see what was inside. Notice the one that was in the clearing is basically black while the one in the woods retains some color. Look at those yummy maggots. <span style="color: rgb(0, 51, 0)">[|grapefruit_in_clearing_opened.JPG] [|opened_grapefruit_woods.JPG]

This is me being an environmentalist and consuming the garbage for the greater good! [|Pedro_eats_garbage.JPG]

=Sources=

[|http://www.esajournals.org/perlserv/?request=get-abstract&doi=10.1043%2F0012-9658(1989)070%5B0097%3ANALCAP%5D2.0.CO%3B2&ct=1] from Ecological Society of America online journals written by Barry R. Taylor, Dennis Parkinson, and William F. J. Parsons http://adsabs.harvard.edu/abs/1999GBioC..13..575M Harvard- good source http://jpe.oxfordjournals.org/cgi/content/short/rtn002v1 Oxford- also good source http://news.therecord.com/article/354044 http://www.madsci.org/posts/archives/1999-03/921124621.Gb.r.html

<span style="color: rgb(0, 51, 0)"> Some final notes: Credit to Will and Colin for building the cages and fixing chicken wire upon them Credit to Will for the intro and the pictures Credit to Colin for Materials in wiki page Credit to Colin and Pedro for collecting trash and putting it in the cages (and to Colin for buying the fruit) Credit to Pedro for the wiki page write up including all parts except the intro and materials Credit to Will for adding some stuff (see history) Credit to Mr. McNeil for the grade (and being awesome) and Have a great summer!!