The Effect of a Solution with Nutrients on
Phytoplankton
Background: In the past fifty years the amount of carbon dioxide
being placed into the environment has exploded greatly. Scientists
have found that a microscopic aquatic plant known as
phytoplankton that can take in Carbon Dioxide (CO2) and water
and produce oxygen. This process is known as photosynthesis and
is one of the most important factors for animal life. Phytoplankton
like all plant life, need phosphates and nitrates to live and grow
better with iron. Phytoplankton are a big part in the aquatic food
chain. Without these little buggers all other life aquatic life would
not exist. Because of this, scientists need to find a way to keep
these buggers alive, hence us.
Hypothesis:
If nutrients and iron are added to the solution containing phytoplankton
then their growth rate will be higher than compared to the control and
nutrients only experiments.
If nutrients and iron are added to the solution containing phytoplankton
then their growth rate will be higher than compared to the control but a
lower count of phytoplankton then in the solution containing both nutrients
and iron.
If nothing is added to the solution containing phytoplankton then there will
be mild success at first but then will decrease and will not have as much as
the nutrient and iron solution and the nutrient solution.
Materials
-
10 mL of phytoplankton culture
50 mL of filtered seawater
50-250mL Erlenmeyer flask
Cotton ball
Available light source (sunny window is fine) - 3-300 µl pipettes
Nitrate, Phosphate and Iron nutrient solutions
Wax pencils
Microscopes and microscope slides
Spectrophotometer (if possible)
Protocol
 Obtain three beakers, label them "Control", "+Nutrients", and
"+Nutrients and Iron"
 Add 100mL of seawater to the labeled beakers
 Add the appropriate things to the corresponding beaker
 Place the beakers under a light source (sunny window is fine)
 Every day for 10 days, make observations and take notes in
regards to the phytoplankton by using microscopes and the
spectrophotometer.
Data
Amount of phytoplankton
Spectrometer Data
Conclusion
In conclusion my hypothesis’s turned out to be correct slightly. My
hypothesis’s stated the following.
If nutrients and iron are added to the solution containing phytoplankton
then their growth rate will be higher than compared to the control and
nutrients only experiments.
If nutrients and iron are added to the solution containing phytoplankton
then their growth rate will be higher than compared to the control but a
lower count of phytoplankton then in the solution containing both nutrients
and iron.
If nothing is added to the solution containing phytoplankton then there will
be mild success at first but then will decrease and will not have as much as
the nutrient and iron solution and the nutrient solution.
Out of all the other groups shown on the data, the nutrients and
iron added to the phytoplankton seemed to have the best result in the
fact that it had the most phytoplankton growth. The statistics for
the nutrients showed that the population jumps at some points but
they mostly stayed at a range between 5-10 phytoplankton. The
control though showed to be the least successful in cultivating
phytoplankton. What I mostly got out of this lab is that nutrients
are what keep phytoplankton alive. Keeping a large set of data
makes for a more accurate conclusion and answer as it shows the
average between the facts or false statements. This beneficial action
turned out for the best. Although To my shock the group with the
nutrient solution was almost in the same range as the control group
for the Spectrometer measurements. This out could have been a
careless mistake in my groups data collection while doing the
procedure for that day. Every group with the same assignment as
ours seemed to have the same conclusion. The numbers for each
phytoplankton count also seemed to average ours. Looking at the
data from each set of groups, iron fertilizing seemed to multiply
more. This shows that iron is probably a large factor towards
eutrophication. Though iron has helped make phytoplankton grow
more, too much of it can damage life in the water as it can start
an algal bloom.