Sunscreen Effects on Brine Shrimp

ISEF Category: Earth and Environmental Sciences

Subcategory: Environmental Effects on Ecosystems  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A sunscreen bottle can look harmless, but its ingredients can move through water and reach tiny animals fast. Brine shrimp are a good test species because they hatch quickly and react in ways you can measure on video. You can compare cheap formulas, mineral sunscreens, and products labeled reef-safe. That gives you a real environmental question with data you can collect yourself.

What Is It?

This project asks how dissolved sunscreen affects Artemia, also called brine shrimp. Artemia are tiny crustaceans that hatch from eggs and swim in short bursts. If a chemical slows hatching or movement, you can measure that change and compare products.

Think of the shrimp like a tiny car on a test track. Hatch rate tells you how many cars make it out of the garage, and motility tells you how well they drive once they start moving. OpenCV can help you turn video into numbers, such as speed, distance traveled, or how often the shrimp change direction.

The big idea is exposure. In water, chemicals can spread, interact with salts, and act differently than they do on skin. That makes this a useful model for aquatic toxicity, which means how a substance affects living things in water.

Why This Is a Good Topic

This is a strong science fair topic because you can change one variable at a time, measure clear outcomes, and compare real consumer products. It connects to water pollution, product labeling, and marine ecosystem health. You can learn experimental design, video tracking, data cleaning, and basic statistics without needing a university lab.

Research Questions

• How does sunscreen brand affect Artemia hatch rate in seawater-equivalent solution?
• What is the effect of mineral versus chemical sunscreen on Artemia swimming speed?
• Does dilution level change the impact of sunscreen leachate on Artemia motility?
• To what extent do products labeled reef-safe differ from standard sunscreens in brine shrimp survival?
• Which sunscreen ingredient category is associated with the largest change in tracking-based movement metrics?
• How does exposure time affect the number of active Artemia in each treatment?

Basic Materials

• Artemia cysts (brine shrimp eggs).
• Table salt or marine salt mix.
• Distilled water.
• Clear plastic cups or small beakers.
• Disposable pipettes or plastic droppers.
• Cheap consumer sunscreen samples, including mineral, chemical, and reef-safe-labeled products.
• Digital kitchen scale with 0.1 g accuracy.
• USB microscope or phone microscope attachment.
• Laptop or desktop computer.
• Tripod or fixed stand for the camera.
• LED desk lamp with consistent white light.
• Timer or stopwatch.
• Notebook or spreadsheet for recording hatch counts and motility scores.

Advanced Materials

• Artemia cysts and standard hatching setup.
• Analytical balance.
• Glassware for preparing treatment solutions.
• Magnetic stir plate and stir bars.
• Fluorescence-safe or low-glare imaging chamber.
• Higher-resolution USB microscope or stereomicroscope with camera.
• Computer with Python, OpenCV, and tracking workflow.
• ImageJ for frame checks and image measurements.
• R software or Python statistical libraries for analysis.
• Dissecting tools and transfer pipettes.
• Water quality meter for salinity, pH, and temperature checks.
• UV-Vis spectrophotometer for comparing extract concentrations if available.

Software & Tools

• OpenCV: Tracks shrimp movement frame by frame and converts video into motion measurements.
• ImageJ: Checks image quality, helps measure scale, and lets you inspect frames before tracking.
• Python: Organizes data, runs tracking scripts, and makes plots for hatch rate and motility.
• Google Sheets: Keeps treatment labels, counts, and summary tables in one place.
• R: Runs statistics such as group comparisons, effect sizes, and simple models.

Experiment Steps

1. Define one clear exposure variable, such as product type, ingredient class, or dilution level.
2. Choose outcome metrics that match the biology, such as hatch success, movement speed, or fraction of active shrimp.
3. Design a control group that matches the saltwater conditions but leaves out sunscreen.
4. Plan your video setup so the camera angle, lighting, and background stay fixed across trials.
5. Build a tracking workflow that turns video clips into repeatable numbers instead of subjective motion scores.
6. Choose a comparison plan and statistics method before collecting data, so your sample size matches your question.

Common Pitfalls

• Using cloudy or oily samples that block the camera view and break motion tracking.
• Letting lighting change between clips, which shifts the background and confuses OpenCV.
• Comparing sunscreens with different amounts of carrier oil, which can hide whether the active ingredient or the formula base caused the effect.
• Counting hatch success too early or too late, which makes one treatment look stronger than it really is.
• Mixing shrimp from different batches without randomizing, which can add batch effects that look like a chemical result.

What Makes This Competitive

A stronger project will test more than one product class and back up the claims with clean tracking data. You can raise the level by standardizing exposure, using blinded scoring for hatch counts, and reporting effect sizes, not just p-values. A smart comparison across mineral, chemical, and reef-safe-labeled sunscreens can reveal gaps between marketing and actual bioeffects. A well-documented video analysis pipeline also helps your work stand out.

Project Variations

• Compare baby sunscreen products and adult sunscreen products to see whether formulation changes alter brine shrimp responses.
• Test only mineral sunscreens with different zinc oxide particle sizes to ask whether physical formulation changes matter.
• Analyze not just speed, but also turning rate and path straightness to capture subtler motility changes.

Learn More

• PubMed: Search for review articles on sunscreen ingredients, aquatic toxicity, and Artemia bioassays.
• NIH PubChem: Look up chemical properties and hazard data for common sunscreen ingredients.
• NOAA Ocean Service: Find background on marine pollution, coastal ecosystems, and water-quality impacts.
• USGS Water Science School: Read about how contaminants move through water and interact with aquatic systems.
• MIT OpenCourseWare: Use introductory biology, environmental science, or data analysis materials to strengthen your experimental design.
• ImageJ Documentation: Learn basic image measurement and frame inspection workflows from the official help pages.