An Exploration of Algal Blooms Caused by Phosphates in Fertilizer
Chandni Sanariya
Lorraine Fitzmaurice
David Muchene
What range of concentrations of phosphate can trigger an algal bloom?
Comments:
Rubric:
5 Points Each
- clear statement of research question + hypothesis
- intro have necessary info why question important
- experiment designed appropriately
- procedures in enough detail
- experiment design well constructed and appropriate for hypothesis
- data presented clearly
- conclusions supported by data
- references properly and adequately cited
- descriptive title
- individual sections delineated
- highlighting major concepts
- short text segments
- visuals to enhance
- color to enhance
- no grammar errors
- all members contribute
- able to answer questions
- time length 8-12 min
- did presenters seem knowledgable
- and were they good audience members
Introduction
In recent years, eutrophication has become a significant problem for freshwater ponds and lakes. During eutrophication, a nutrient overload causes the algae in the water to proliferate exponentially. As the algae bloom, sunlight cannot reach the depths of the water, causing other plants to die. These plants are decomposed by bacteria, which use up all of the available oxygen, killing fish and other organisms. Phosphorus is the leading cause of nutrient overload and enters the water as run-off carries phosphorus containing agents such as fertilizers and detergents.
We don't really have a hypothesis- we know what's going to happen, we just want to know at what concentration, so maybe we should call it the research question or something.
Research Question
What concentration of phosphorus from a common garden fertilizer will trigger an algal bloom in pond water?
I'm pretty sure that the hypothesis is part of the rubric which i lost so i can't make sure.. but i just came up with this here:
Hypothesis **Changed!!
The hypothesis is that the greatest algal bloom will occur at the greatest concentration of phosphorous in the water sample, which for this particular expirament it was the 2.5 grams of phosphorous.
Procedure **Changed!!
To test the experiment, there were six samples of pond water and which had been distributed different amounts of fertilizer in each. Suspended solids was used to determine the weight of solids (algae, among other stuff such as sand, debris, etc.) in each sample. The suspended solids was done bye taking a 20 mL sample for each concentration of phosphorous and filtering all the water through it. It is then baked for 1 hour to dry up the moisture leaving only the solids from the sample. The weight of the filter and the tray was measured before the sample was filtered and after it was baked. Then after a 8 day incubation period, suspended solids was used again to determine the weight. The percent absorbance of phosphorous was also measured after the incubation. This data was used to determine the results.
Results/Data
- Comparison between the growth of the algae with the blank
- Comparison between the growth of the algae with the phosphorous levels.
Conclusion **Changed!!
In the experiment, the purpose was to determine which concentration could cause the most growth of algae in our pond water. After a week of incubation, the growth of the algae was compared to the blank without the fertilizer and it was determined that algae growth peaked at ___g of phosphorous. It was also noted that the absorbance of the phosphorous steadily decreased with each correlating concentration, meaning that the phosphorous was being used up more quickly due to the larger growth in each consecutive sample.
It also very important to note that there may have been other substances within the fertilizer that may have diminished or enhanced the growth of the algae in our sample water. All in all, the experiment proved that the greatest algal bloom occured at a concentration of ___.
Suspended Solids Before Incubation
| Sample (g of phosphate) | Dish # | Weight of Dish (g) | Weight after Algae is Dried out (g) | Weight of Algae |
| 0 g (Blank) | 1 | 2.89 | 2.87 | -0.02 |
| 0.05 g | 2 | 2.86 | 2.87 | 0.01 |
| 0.1 g | 3 | 2.95 | 2.90 | -0.05 |
| 0.5 g | 4 | 2.88 | 2.89 | 0.01 |
| 1 g | 5 | 2.88 | 2.90 | 0.02 |
| 2.5 g | 6 | 2.88 | 2.90 | 0.02 |
Suspended Solids After Incubation
| Sample (g of phosphate) | Dish # | Weight of Dish (g) | Weight after Algae is Dried out (g) | Weight of Algae |
| 0 g (Blank) | 47 | 1.74 | 1.75 | 0.01 |
| 0.05 g | 46 | 1.73 | 1.75 | 0.02 |
| 0.1 g | 48 | 1.75 | 1.76 | 0.01 |
| 0.5 g | 55 | 1.75 | 1.76 | 0.01 |
| 1 g | 24 | 1.75 | 1.76 | 0.01 |
| 2.5 g | 44 | 1.72 | 1.75 | 0.03 |
Change in Phosphorous Levels
| Sample (g of phosphate) | Original Amount (g/L) | Amount After Incubation (% Asorbance) |
| 0 | 0 | 0.021 |
| 0.05 | 0.067 | 0.392 x10 |
| 0.1 | 0.133 | 0.308 x10 |
| 0.5 | 0.667 | 0.117 x10 |
| 1.0 | 1.333 | 0.078 x10 |
| 2.5 | 3.333 | 0.019 x10 |
| 2.5 | 3.333 (not diluted) | 0.700 |
- For the 0.05 to 2.5 samples we had to dilute it with water by a factor of 10 because reading was too high. 1:10 dilution
