Brine Shrimp and Salinity Correlation Lab

Brine Shrimp and Salinity Correlation Lab Abstract This lab focused on understanding the relationship between brine shrimp and the salinity of their environments and what this relationship means in a real world aspect. By placing a number of brine shrimp eggs and counting the number of hatched brine shrimp each day for two days, I was able to collect sufficient data to determine that as the salinity of solution increased, so did the hatching viability of the eggs. This correlation indicates the differences within a population of organisms as well the the genetic mutation in brine shrimp that allow them to cease development inside the egg until favorable hatching conditions take place. Introduction Understanding the relationship between brine shrimp and salinity levels was an essential requirement before I could tackle this lab. Brine shrimp are small crustaceans that can be found in various saltwater lakes around the world. When the eggs are produced, they hatch quickly, however, when conditions become less favorable, the shrimp produces cysts (encased embryos that cease development) until conditions are favorable to hatch. Therefore, the purpose of the lab is to determine the effect that different salinities of solution had on the hatching of the brine shrimp. To do this, we placed a number of brine shrimp into beakers of various salinities and followed their development over the course of two days. Hypothesis If brine shrimp populations are influenced by salinity and brine shrimp are usually found in saltwater, then I predict the solution with the most salinity will have the greatest hatching viability. Materials • Brine shrimp eggs • Scissors • Paintbrush • Double-sided tape • Dechlorinated water • Permanent marker • Stirring rod • Graduated cylinders • Scale • Weigh boats • Lab spoons • Sodium Chloride • 5 pipets • 5 microscope slides • 1 stereomicroscope • 5 petri dishes • 5 beakers Procedure Day 1 1. Prepare and label five beakers of 30-mL salt solutions with the sodium chloride and dechlorinated water. The solutions should be 0%, 0.5%, 1.0%, 1.5%, and 2.0% NaCl. 2. Label five petri dishes with the correlating NaCl solution percentages. 3. Use a graduated cylinder to measure 30 mL of 0% salt solution and pour it into the petri dish labeled 0%. Repeat for the remaining concentrations. 4. Measure and cut 1.5 cm of double-sided tape. 5. Stick the double-sided tape to a microscope slide. 6. Lightly touch the paintbrush to the side of the bag containing the brine shrimp eggs. Your goal is to collect around 20 eggs on the bruhs. You do not want to cover the tip of the brush in eggs. 7. Dab the paint brush onto the tape on the microscope slide. 8. Examine the slide under the stereomicroscope. 9. Count the number of eggs on the slide and record this number on the table. 10. Place the microscope slide in the 0% petri dish, tape-side up, and place the lid on the dish. 11. Follow steps 4-10 for the the remaining slides and dishes. Record all data onto the table. 12. Allow the dishes to sit at room temperature undisturbed for 24 hours. Day 2 1. Examine one petri dish with a stereomicroscope. 2. Count the number of swimming brine shrimp. With a pipet, gently catch them and move them into another container - your instructor may have prepared a beaker of saltwater for this purpose. Try not to remove excess water with the pipet. Record the number of swimming shrimp in the table. 3. Count the number of dead or partially hatched shrimp and record this data onto the table. 4. Count the number of unhatched eggs and record this data onto the table. 5. Repeat steps 1-4 for each of the petri dishes. Use a separate pipet for each petri dish. Day 3 1. Examine each petri dish with a stereomicroscope. 2. Repeat steps 2-4 from Day 2. Data 0 hours 24 hours 24 hours 24 hours 48 hours 48 hours 48 hours Dish # % NaCl # Eggs #Eggs # Dead / Partially Hatched # Swimming # Eggs # Dead / Partially Hatched # Swimming Hatching Viability (%) 1 0 38 18 8 1 0 26 0 2.6 2 0.5 65 24 30 1 0 52 2 4.6 3 1.0 67 20 27 9 0 45 2 16.4 4 1.5 37 24 2 11 0 25 1 32.4 5 2.0 42 24 4 14 0 27 1 35.7 Conclusion By looking at the data table and the graph provided, it’s evident to see that as the salinity of the the brine shrimp’s environment increases, the hatching viability also increases.This proves my original hypothesis. This data also reveals another truth about the characteristics of brine shrimp. Brine shrimp have developed a beneficial trait over generations that allows it to essentially freeze time and wait until the perfect time to hatch, when the salinity of the environment is at a favorable level. This leads to another point that not all brine shrimp are the same, because some shrimp did hatch at 0% solution or 1.5%. This means the preferences in salinity vary amongst a population of brine shrimp. There were many sources of error in this lab that could have easily skewed the results. First off, it’s easy to accidentally create solutions that are not of the desired levels of salinity. Secondly, it was a difficult take to suck out the living brine shrimp in the solution using the pipet. This could have easily lead to sucking up either dead shrimp or eggs in the umbrella stage which would have altered the data of the lab.