In a remarkable demonstration of cross-curricular application, a joint cohort of students from the [SCI-PHY] Physical Sciences and [CS-ADV] Computer Science tracks has published preliminary findings that challenge existing assumptions about microplastic sedimentation in the Baltic Sea during winter months.
The initiative, known internally as “Project Jää” (Ice), is part of the college’s ongoing “Baltic Watch” commitment. While summer data on water quality in the Archipelago Sea is abundant, winter data has historically been scarce due to the logistical difficulties of sampling in sub-zero conditions.
Braving the Elements for Data
Led by Mrs. Li Wei (Head of Chemistry) and Year 13 student lead Matias Aaltonen, the team spent three weekends in December and early January collecting ice core samples near the Ruissalo channel. The conditions were far from forgiving.
“It was character-building, to say the least,” remarked Matias. “On the second day of collection, our atmospheric drone failed because the lithium batteries couldn’t handle the -18°C ambient temperature. We had to revert to manual drilling and manual recording. It wasn’t the high-tech scenario we planned, but it taught us that science is often about troubleshooting frozen equipment with numb fingers.”
The Methodology
Despite the technical setbacks, the samples retrieved were analysed in the college’s spectroscopy lab. The students were looking for specific spectral signatures of Polypropylene (PP) and Polyethylene Terephthalate (PET)—plastics commonly associated with maritime shipping and consumer waste.
Simultaneously, the Computer Science stream, supervised by Dr. Elias Korhonen, utilised the raw data to train a predictive model. Instead of standard linear regression, the students applied a ‘Random Forest’ algorithm to correlate the density of microplastic particles with the frequency of commercial ferry schedules over the past decade.
A Surprising Correlation
The preliminary results suggest that the freeze-thaw cycle of the Baltic ice layer acts as a “temporal trap” for microplastics, concentrating pollutants in specific strata of the ice. The model indicates a 14% higher concentration of PET fragments in ice forming within 2km of major shipping lanes compared to control samples taken from sheltered inlets, a deviation significantly higher than the standard margin of error.
Mrs. Wei commented on the academic maturity of the group: “What impressed me was not just the data collection, but the statistical integrity. When the students found an outlier in the data, they didn’t discard it; they re-sampled. That is the discipline of a scientist, not just a student looking for a grade.”
Next Steps
The findings have been submitted as a poster presentation for the upcoming Nordic Youth Science Conference in Stockholm later this spring. The data set has also been shared with the Department of Geography at the University of Turku as part of our Junior Fellow partnership.
While “Project Jää” has concluded its field phase, the analysis continues. For the students involved, the project has offered a glimpse into the reality of environmental research: it is cold, it is tedious, and it is prone to error—but the discovery of a new truth makes every frozen hour worthwhile.
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