1. Glyphosate Effects on algal population
Patrick Keating
Pittsburgh Central Catholic High School
PJAS 2019
Grade 9

2. Pesticide Runoff
One of the fastest growing and largest threats to global water resources
Rainwater collects the excess chemicals, flows into rivers and lakes, causes toxicity and/or eutrophication
Eutrophication results in oxygen crash
Kills many organisms

3. Herbicide Used to eliminate unwanted plants
COULD HARM NON-TARGET SPECIES
Could harm aquatic organisms
Could affect algal growth
GLYPHOSATE

4. ROundup 2% Glyphosate and isoproplyamine salt
2% pelagonic acid and related fatty acid
96% Other ingredients

5. Glyphosate Common Herbicide Main ingredient in Roundup
Kills broad leafed plants and grasses

6. Chlamydomonas reinhardtii
Round, flat, green algae
Photosynthetic
Found in many places
Can thrive in complete darkness, carbon source
Often used in biological research

7. Euglena gracilis Cylinder-shaped, unicellular, green Algae
Found worldwide, typically in fresh water or sewage systems
Photosynthetic, Hetrotroph
Also commonly used in biological research

8. Purpose
To determine the effects of Roundup on algal population growth

9. Past Studies
“Combination Effects of Herbicides on Plants and Algae” states that most of the herbicides used were harmful to plants and algae
“Herbicides and Insecticides Effects on Green Algae and Cyanobacteria Strain” stated that the herbicides that were able to be tested were “extremely toxic” to green algae

10. Hypothesis
Null: Roundup will not have a significant effect on growth of Chlamydomonas reinhardtii or Euglena gracilis
Alternative: Roundup will have an effect on growth of Chlamydomonas reinhardtii or Euglena gracilis

11. Materials Soil water Spring water Spectrophotometer Hemocytometer
23 Watt Lightbulb
13x100 Culture Tubes
Micropipettes (p1000, p200, p20)
Chlamydomonas reinhardtii
Euglena gracilis
Glyphosate
Test Tube rack

12. Procedure
Made test tube concentrations with both types of Algae, (see Slide 13)
Placed 13x100 culture tubes beneath 23 watt lightbulb for 12 hours a day, complete darkness for other 12 hours
Mix tubes around before measuring in the spectrometer
Measure all thirty tubes in the blanked spectrometer at 430nm (Carolina Science Spectrophotometer)
Cell counts performed from days to
On day 10, take Hemocytometer cell counts performed

13. Test Tube Concentration
Control (0%)
0.05%
0.005%
Spring Water
1.5ml
1 ml
1.45 ml
Soil Water
Algae
2.5ml (Euglena)
2.5 ml (Euglena)
2.5 ml (chlamyd)
Glyphosate (10% stock)
0 ml
0.5 ml
0.05 ml

14. Glyphosate Effects on Euglena

15. Glyphosate Effects on Chlamydomonas

16. Hemocytometer Readings: Euglena0%
0.005%
0.05%
P Value:

17. Hemocytometer Readings: is Chlamydomonas0%
0.005%
0.05%
P Value: E-8

18. Conclusion The ANOVA allows null rejection
Different concentrations of Glyphosate significantly effected algal growth for both species of algae
Significant effects on 0.05% concentrations of both algae

19. Limitations and Extensions
Limited range of exposures
Unnatural environment
Optimal Lighting?
Spectrophotometer evidence not completely reflective of population size
Extensions:
Wider ranges of exposure
More herbicides
Use natural pond
Optimize lighting and care
Synergistic Effects with other chemicals

20. Bibliography
Britannica, The Editors of Encyclopaedia. “Euglena.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 27 Dec. 2017,
“Chlamydomonas Reinhardtii.” Science360 News Service | National Science Foundation, news.science360.gov/obj/pic-day/49c9d5f2-c84a-4e13-9b0b-5b8cecbd29df/chlamydomonas-reinhardtii.
“Chlamydomonas Reinhardtii v4.0.” Home - Pseudomonas Fluorescens Pf0-1, genome.jgi.doe.gov/Chlre4/Chlre4.home.html.
Piri, M., and V. Ördog. “Herbicides and Insecticides Effects on Green Algae and Cyanobacteria Strain.” Iranian Journal of Fisheries Sciences, Iranian Journal of Fisheries Sciences,
“Runoff, Factors Affecting.” Water Encyclopedia, Affecting.html.
algae_Do_species_and_test_systems_matter

21. ANOVA: Euglena (day 6) Anova: Single Factor SUMMARY Groups Count Sum
Average
Variance
Column 1 5
0.66
0.132
7E-05
Column 2
2.33
0.466
Column 3
0.86
0.172
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups 2
1.13E-10
Within Groups 12
Total 14

22. ANOVA Chlamydomonas (Day 6)
Anova: Single Factor
SUMMARY
Groups
Count
Sum
Average
Variance
Column 1 5
0.89
0.178
Column 2
3.58
0.716
Column 3
1.23
0.246
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups 2
E-10
Within Groups 12
Total
0.8792 14