Entropy Generation In An Ecosystem

EXPERIMENT

Entropy generation in an ecosystem

An experiment was carried out under laboratory conditions. In this section 110 disposable plastic cups of commercial size No. 10 were used as plant pots. In each plant pot was added 250 g of black sand obtained of a nursery. Then, seeds of ball radish (raphanus sativus) were planted in each plant pot, which it were divided in 11 groups of 10samples. Next, contaminant, in this case diesel, was introduced on each crop group as shown in Table 1. The amount of diesel used is identified by a code for each plants group.

|Code |Amount of Contaminant |
|Control |0 ml |
|Group A |1 ml |
|Group B |2 ml|
|Group C |3 ml |
|Group D |4 ml |
|Group E |5 ml |
|Group F |6 ml |
|Group G |7 ml |
|Group H |8 ml |
|Group I|9 ml |
|Group J |10 ml |

Table 1. Diesel concentration on each plants group.

Once complete the previous process, each planting was irrigated every morning with 25 ml of water for a period of 20 days. After this time, each plant was measured from base to highest point. Table 2 shows height average of growth for eachplants group.

|Code |Height Average |
|Control |8.61 cm. |
|Group A |7.83 cm. |
|Group B |7.38 cm. |
|Group C |6.55 cm. |
|Group D |6.35 cm. |
|Group E |5.77cm. |
|Group F |4.44 cm. |
|Group G |3.58 cm. |
|Group H |2.99 cm. |
|Group I |2.41 cm. |
|Group J |1.96 cm. |

Table 2. Height average on each groups plants according tocontaminant level.

Figure 1 shows the final average height for each plants group. The maximum height was attained by control plants. This effect is connected with diesel levels as shown in Figure 2 where, X axis represents code of each plants group and average height of plants in cm. is represented for Y axis.

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Figure 1. Difference averages heights between each plants group

Figure 2.Final average height as a function of contaminant level.

Then, each plants group is introduced into a chamber made of polystyrene; volume of chamber is 0.048 m3. In this box is simulated a closed and adiabatic systems; inside of chamber is installed a bulb of 25 W as light source or energy for plants. The power of light bulb is reduced to 24 W with a rheostat; equally inside chamber there is athermocouple connected to a multimeter that is used for measure the air temperature which, it is recorded every 10 minutes up to a steady state. In Figure 4 shown materials used during this test.

[pic]
Figure 3. Materials used in laboratory.

The goal is to use each plants group for simulate an ecosystem, a forest for example, and evaluate how the contaminant levels on plants alter energy flows.As an example of procedure, process used for obtain behavior of energy flow inside the chamber shown below: the initial temperature all tests is 30°C (303 K). The first test was done without plants inside the polystyrene box, so all the energy inside chamber is absorbed by air; for this test, the final stable temperature was 38 °C (303 K). Once complete the previous process, the chamber is...