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Relationships Between Benthos, Water Chemistry and Human Activity in Jõulumäe Trench
Organization(s):Estonian Learning Expedition
Country:Estonia
Student(s):Mari-Ann Loit (Viljandi Gümnaasium), Rasmus Roosileht (Antsla Gümnaasium), Mirell Mattisen (Rakke Kool), Arina Jakovleva (Narva Vanalinna Põhikool), Aleksandra Vaarik (Kilingi-Nõmme Gümnaasium), Joosep Metsaalt (Muhu Põhikool), Lille-Mai Kangur (Miina Härma Gümnaasium)
Grade Level:Secondary School (grades 9-12, ages 14-18)
GLOBE Member(s):Paula Liisa Eplik, Jaanus Terasmaa
Contributors:Laura Altin
Johanna Raudsepp
Report Type(s):Virtual Science Symposium Report
Protocols:Nitrates, pH, Water Transparency, Dissolved Oxygen, Alkalinity, Conductivity, Water Temperature, Freshwater Macroinvertebrates
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Language(s):English
Date Submitted:2026-01-27
GLOBE Estonia Learning Expedition 2025 in Pärnumaa, Jõulumäe, focused on investigating a drainage trench located next to Jõulumäe Recreational Sports Centre. The aim was to provide an overview of the ecological status of the waterbody and to explore the relationships between benthic community composition, water chemistry, and the intensity of human activity. We formulated three research questions: How does the composition of benthic organisms change along the trench? How are water properties influenced by human activity? How is the benthic community composition related to water chemistry?
This study is important because, at present, the Estonian state is able to monitor the status of only 14% of flowing waters and 3% of lakes. Monitoring a greater number of waterbodies would contribute to the protection of Estonian aquatic ecosystems, since detecting problems at an early stage makes it possible to reverse the deterioration of freshwater ecosystems and drinking water quality.
On August 17, 2025, we collected data from nine monitoring sites distributed along a 3-km section of the trench, measuring several water quality parameters: pH, temperature, electrical conductivity, hardness, nitrate, and phosphate content. In addition, at each monitoring site we used a kick-net to take two samples and observed the benthic invertebrate communities present. For data collection, we employed a multimeter and water analysis tools.
As a result of the study, we obtained an overview of the condition of the Jõulumäe trench: overall water quality was poor, the trench showed signs of eutrophication, and in one monitoring site the phosphorus concentration exceeded the threshold for the “very bad” status class. Signs of human activity were recorded at six out of nine sites, and in general, phosphorus concentrations were higher in sites affected by human activity, whereas nitrate was not detected in any site. The benthic community composition showed clear variation along the trench, although no direct relationship with water chemistry could be identified from our results.