Ecobottle Formula Lab
1. Introduction
The eco-bottle lab required the use of two plastic bottles. As a group we cut up these
bottles and separated the top layer to be designated for the radish and the bottom layer for the
fish, Zebra Danio. The bottom layer also included duckweed, rocks, and Elodea. As a group we
used ammonia, CO2, and nitrate test kits. We recorded our data for five weeks. We also
checked the temperature, pH levels, and dissolved oxygen in order to make sure the fish was in
a sustainable environment. The ammonia test kit involves adding different reagents, then
waiting twenty minutes, and then matching the color to the slider to determine ppm. The CO2
test is a titration, and we add phenolphthalein into indicator. The nitrate test kit is much like the
ammonia test kit but only requires a five minute waiting period. The purpose of conducting this
lab was to better understand the various elements within an ecosystem and the habitat required
for sustainability of the ecosystem.
1a. An ecosystem is an interrelationship with the plants, animals, weather, soil, sun, and
atmosphere. An aquatic ecosystem is an ecosystem within the body of water in which the
organisms that sustains in this environment depend on each other and the habitat. Some
examples of an aquatic ecosystem include freshwater ecosystem, salt marshes, and marine
ecosystem. A terrestrial ecosystem is an ecosystem within land, which include biotic and abiotic
factors. Examples of a terrestrial ecosystems include tundra, temperate deciduous forest,
tropical rain-forest, grassland, desert, and taiga. In this lab we can see that Zebra Danio,
duckweed, and Elodea were part of the aquatic ecosystem. Duckweed was important in our
eco-bottle because it provides shade, cleans out excess nutrients in the water, and is a source
of food for Zebra Danio. Eledeo is an excellent source of oxygen, shade, and purification of
water. The radish, and soil can be considered to be part of the terrestrial ecosystem. The soil
can be considered a base to the radish. It provides nutrients in the soil which helps it grow. The
radish also uses the help of the sun in the process of photosynthesis which provides oxygen to
the atmosphere.
1b. The two main chemical reactions responsible for carbon cycling is photosynthesis and
respiration. The cycle begins when carbon dioxide dissolves from the atmosphere into the
water. This forms carbonic acid. Plants in the aquatic ecosystem absorb the carbonic acid
through photosynthesis. The carbon cycle starts with autotrophs, plants. This cycle begins with
photosynthesis of plants. Plants use carbon in order to make their food, glucose. CO2 is in the
atmosphere and during photosynthesis plants use the sun to absorb CO2. Then the CO2 is
converted into glucose. The chemical equation for photosynthesis is 6CO2 + 6H2O + energy
(from the sun) > C6H12O6 + 6O2. Heterotrophs then eat the plants for example fish. The
Carbon is now transferred to the animal (fish). Other animals who eat animals, secondary
consumers, also get the carbon. This is how the food chain works. This carbon has to be
returned to the atmosphere through the process of cellular respiration. When plants and animals
breathe, they release the carbon content into the atmosphere. Also when plants or animals
wants energy they break down glucose. This break down of glucose helps convert it to CO2,
which is then released into the atmosphere. The chemical equation for respiration is C6H12O6
+ organic material + 6O2 > 6CO2 + 6H2O + energy. If the animal (fish) dies then decomposers
such as fungi, bacteria, and marine worms pursues the dead animal releasing CO2. This means
that the carbon content has been returned back into the atmosphere, then the carbon cycle
continues again. CO2 decreases the pH in the water. This is because CO2 reacts with water
forming carbonic acid. Carbonic acid alienates hydrogen and bicarbonate ions which then
decreases the pH level of the aquatic ecosystem. When fish have left behind feces in the water
the pH level is slightly higher. This is due to ammonia ions reacting with water. The more urine
in the water the higher the pH level. The fish urinate more as the pH will be on the acidic side.
This is because urine it-self is acidic and urine makes water more acidic too.When the water is
acidic, let's say pH is 5, this will harm young fish and eggs. Low pH levels can cause the fish to
become stressed which can lead to death or decrease of body mass making fish less able to
have the energy to compete for its food. High pH levels can kill the fish, and cause harm to its
gills and even eyes. As water temperature increases the ability of water to dissolve CO2
decreases. Meaning that the colder the water the more CO2 it is able to dissolve. The carrying
capacity of the radish were low in this experiment. Which means that the carbon absorbed by
the autotrophs were limited by the amount of radishes there was in this experiment.
1c. Nitrogen cycle starts when there is a form of precipitation for example snow and rain.
The bacteria that is in water (cyanobacteria) will convert from nitrogen to ammonia this process
is called nitrogen fixation. The equation for nitrogen fixation is N2 + 8H + 8e- >2NH3 + H2. The
ammonia is then combined with oxygen in a process called nitrification. At this state the
ammonia has been converted into nitrite by bacteria in soil. The formula for nitrification is NH3 +
1.5O2 > NO2- + H+ + H2O. Nitrifying bacteria then helps nitrite become nitrate. This process is
called nitration. The formula for nitration is NO2- + 1/2O3 > NO3. Then a process called
assimilation takes place. This is when plants, fish, and other living organisms are able to absorb
this nitrogen in order to get the nutrition the organisms need. The formula for assimilation is
HNO + 8H > NH3 + H2O. Though not all of this nitrogen is used up by these living organisms
but also the bacteria. The bacteria will then return the nitrogen into the atmosphere. This
process is called denitrification. The formula for denitrification is 6NO3- + 5CH3OH > 3N2 +
5CO2 + 7H2O + 6OH. If the living organism dies( zebra danio or elodea) or need to get rid of
waste they will release nitrogen into the water. Then the bacteria converts this nitrogen into
ammonia. This process is called ammonification. The formula for ammonification is NH2 > NH3
+H20 > NH4+ + OH-. The nitrogen continues to do this all over again starting at nitrification.
When nitrogen is introduced in the aquatic ecosystem, it will make the water more acidic
meaning the pH will be lower.
II. Purpose
The purpose of the eco-bottle lab was to get a feel for how each chamber was an
important element for the sustainability of aquatic and terrestrial ecosystems. We evaluated the
conditions for the sustainability of the chambers and the necessary interconnections within the
chambers. We got to observe the changes within the water and soil through the lab kits
(Ammonia, CO2, and nitrate test kits). We are focusing on the nutrient cycle and observing
what nutrient is needed in the eco-bottle.
III.Hypothesis
My hypothesis after first weeks observation was that the temperature will be stable
throughout the experiment due to the schools air conditioning system being pretty stable. I also
assumed that the pH will go up due to the increase of ammonia in the water over time.
Dissolved oxygen levels, nitrate and carbon dioxide levels would stay the same was my
assumption for the first week. The second week as a group we observed that the water was a
lot less clear and that the fish was anxious due to it being at the top constantly. The plant
container was very cloudy the first week but the second week it was far better.From this
observation my hypothesis was that the dissolved oxygen will go up, while the pH and CO2
decreases. The temperature would go up slightly or remain steady. I also believed that
ammonia will go up due to the urination and feces of the fish and the nitrate levels will go down.
Third week we observed that the water was murky and that the fish is less anxious We also
noticed that the Elodea was slowly dying. From these observations I predicted that the dissolved
oxygen and temperature would increase, and that the CO2 would cycle. Ammonia will continue
to increase while the pH and NO3 will stay constant. From the fourth week we saw that the
water looked more polluted and that the fish is swimming at the top once again. The Elodea is
still slowly dying. From this observation I predicted that the dissolved oxygen and nitrate levels
will increase as the temperature would remain at a constant. Ammonia and pH will go up by a
few. CO2 will start to go down. For week five the Elodea looked almost dead and the water
looked dirtier. The fish was still at the top most likely anxious. I mentioned that ammonia levels
would go up throughout the lab and that the temperature would remain at a constant for the
most part. While for the pH, dissolved oxygen, CO2, and NO3, I believed that there would be
variations in some if not all week.
IV. Materials and procedures
Materials:
● Ammonia test kit (LaMotte)
● Carbon dioxide test kit (LaMotte)
● Nitrate- Nitrogen test kit (LaMotte)
● Two 2- liter plastic bottles and its caps
● Sharpie
● Scissors
● Exacto knife
● Soil
● Pebbles/ aquarium rocks
● 9 elodea seeds
● Duckweed
● Zebra Danio
● Fish food
● pH probe/ sensor
● Distilled water
Procedure:
Create eco-bottle
1. Cut a 2 liter bottles to create the eco-bottle. For bottle number one cut the cone looking
part from the cap area. We did not use the cone part of this bottle.
2. The other 2 liter bottle was cut at the line at the bottom of the soda bottle. We needed to
use both the bottom parts of this bottle.
3. We took bottle number one and filled it up with rocks, fish,and duckweed. This bottle
represents the aquatic ecosystem.
4. Bottle number two was faced upside down with the cap on. This bottle was on top of
bottle number one. This section was for the terrestrial ecosystem.
5. Fill bottle number two up with soil, and plant Elodea seeds.
6. Use the bottom part of the second soda bottle to cover up bottle number two. This
finishes the eco-bottle set-up.
Lab testing/ data collection
1. Observe the eco-bottle for five weeks and recording our data.
2. Conduct carbon dioxide the step to step instructions will be provided in the kit. This kit
includes syringe,phenolphthalein, solution and a beaker.
3. Conduct the ammonia test kit and follow the instructions provided in the kit. This kit will
include ammonia #2, ammonia #3, and salicylate ammonia #1.
4. and nitrate tests (the instructions for these are provided inside the test kit boxes)
5. Make sure you have recorded the data from these kits
6. Take data on the temperature and pH. This can be done by the pH probe cleaning the
probe with distilled water before use and then placing it in your aquarium part of the
eco-bottle. The reader will provide you with both pH and temperature. (Record once
stable)
7. Find dissolved oxygen in the water by using a probe. Firstly use distilled water to clean
off the senor. Continuously stir the probe in the water. Record data once the reader is
stably reading your data.
Va. Data analysis and analysis results
Independent Variables:
● Amount of water
● Amount of duckweed
● Type of soil
● Type of plant (Elodea)
● Type of fish (Zebra Danio)
Dependent Variables:
● Sunlight
● pH
● Nutrients (nitrogen and phosphorus)
● Dissolved oxygen
● Fishes sustainability
Controlled/ constant Variable:
● The location of the fish
● Ventilation
● Container
● Pebbles/ rocks in the tank
● Number of fishes (One)
● Presence of plant
● Presence of duckweed
● Water temperature
Vb. The data we collected did have a few trends that I noticed. For weeks 1-3 as the DO
went up so did CO2. Then we approached week 4 and 5 where as the DO increased the CO2
decreases. There was no correlation between ammonia and nitrate from our data. The nitrate
seemed to be constant until week four and five. Whereas ammonia kept increasing until week
five. As for the CO2 and pH there were some trends. As the pH decreased so did CO2 and the
increase of pH causes the CO2 to increase. This trend occurs till we reach week four and five
where the increase of pH decreases CO2 in the water.
Vc. Soil testing results:
In the terrestrial ecosystem of the eco bottle we conducted a soil test. At the beginning
the phosphorus was surplus after the lab it depleted. Nitrogen was surplus at the beginning and
afterwards the soil still had a surplus amount of nitrogen. The pH was 7 both before and after
the lab. The potassium was surplus before and depleted after.
Ve. Data graphs:
As seen on this graph there is a clear correlation between dissolved oxygen and carbon dioxide.
When dissolved oxygen is increased, carbon dioxide decreases. As well as when dissolved
oxygen decreases CO2 levels increase. There is a clear correlation.
This graphs shows how ammonia and nitrate are related, though it is not as clear as the
previous graph there is still some trends. As ammonia increases slightly there seems to be a
decrease in nitrate but this only occurs sometimes. Ex: even though ammonia was stable week
3-4 there is a drastic increase in nitrate levels.
There is a correlation or trend in this graph. You can observe that as the pH levels increase, the
CO2 levels decrease. This can be observed the other way around too. When pH decreases
there is a clear increase of CO2.
VI. Discussion/Conclusion
At the very beginning I came up with a hypothesis that the pH would be very similar
throughout the lab. I also believed that ammonia will rise, and CO2 would cycle slowly but
surely. I also thought that the dissolved oxygen will be stable. At first, my hypothesis was that
the nitrate levels will be completely constant but what caught me off guard was week 4 and
week 5. I believed that the temperature will be constant. I figured that the pH will go up due to
rise in ammonia. My groups data vs. previous years data differs. The closest these datas are
alike in the measure of dissolved oxygen is at the first week. My data had 2.3 ppm and the
previous years data had 2.4 ppm the first week. Dissolved oxygen carried for the following
weeks. For the CO2 my data tends to be cycling whereas the previous years data is decreasing
throughout the weeks. We did not have any similarities here. pH levels for us we're going down
(becoming more basic). Week four and five the eco-bottle slowly started picking up the pH. The
previous years pH went up expect on week four where it dropped from 7.32 to 7.19 then week
five had pH of 7.39. The ammonia levels for us were irregular going from 0.25 the first week
then to 1.50 the second, and then 2+ for week 3 and four. The last week it went back to 0.1
ppm. The previous years ammonia data tends to be cycling. The nitrate levels for us stayed
constant of 1.5 ppm until week four and five. Week four being 2.5 ppm and 4.5 ppm week five.
The previous years data on the nitrate levels is cycling constantly. A possible source of error
that might have occurred in our lab might be when we used the pH probe and the reader kept
changing the levels unexpectedly after being steady for 8 seconds.
Citation for the introduction:
“Carrying Capacity and Limiting Factors,Carbon Cycle, Cellular Respiration & Photosynthesis.”
Home
,https://redpandaspredators.weebly.com/carrying-capacity-and-limiting-factorscarbon-cycl
e-cellular-respiration--photosynthesis.html. 17 November 2019
Study.com
,Study.com,https://study.com/academy/lesson/cycles-of-matter-the-nitrogen-cycle-and
-the-carbon-cycle.html. 19 November 2019
“The Nitrogen Cycle.” Khan Academy
, Khan
Academy,https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/a/the-n
itrogen-cycle. 19 November 2019
“Water Treatment Solutions.” Lenntech Water Treatment & Purification
,
https://www.lenntech.com/aquatic/acids-alkalis.htm. 20 November 2019
