Ecosystems, where living and nonliving organisms are together and have a perpetual interaction, provide various services for functioning of the Earth's life-support system. However, over the past five decades, humans have been damaging the ecosystems more than ever in history to meet growing demands for food, fresh water, timber, fiber, and fuel (MEA, 2005). To prevent the degradation of ecosystems and use their services by thinking about the future of mankind and other living organisms, understanding of ecosystems is crucial. To achieve this, doing only fundamental sciences is inadequate unless the scientific information reaches non-scientists and engages them to act together with an interdisciplinary effort.

Scientific information reaches learners by environmental education aiming to teach individuals understanding environmental concepts, involve them in actions, and make them improve solutions for environmental problems (NAAEE, 2004). To address these problems, science education and environmental education can be linked to each other by citizen science projects (Wals et al., 2014). Citizen science that involves citizens in scientific projects by recording their own observations, monitoring ecosystems, and managing natural resources has gained more attention in recent years (Miller-Rushing et al., 2012). Involvement in citizen science has educational benefits, including increasing interest, knowledge, skills of science inquiry (Peter et al., 2019). Thus, citizen science projects have been proposed to be implemented as an educational tool in schools (Gray et al., 2012).

A minority of research has focused on citizen science in schools. However, it is highly engaging for K-12 students (Trautman et al., 2012). To Kloetzer et al. (2021, p.288), even if it is challenging to integrate citizen science in schools, there are three key factors for success; “institutional and technical support” for teacher participation, “ready-to-use material and lesson plans connected to school curricula" for learning outcomes, and "inquiry-based learning” for students motivation.

Regarding these, in accessible literature examined, only one formal citizen science project aiming at enhancing middle school students’ understandings on ecosystems is found. In that study, eight graders’ knowledge on ecosystem components was reported as improved (Hiller & Kitsantas, 2014). Nevertheless, considering children’s low level of understanding of ecosystems and the call for instructional materials on complex ecosystems (Yucel & Ozkan, 2015), teaching ecosystems is essential even more than ever.

For evaluation of understandings of ecosystems, it may be challenging for children to express themselves with words. Researchers suggest drawings to reveal the understandings of children due to their authentic way of communication (McNair & Stein, 2001). Therefore, it can be used as an evaluation tool of middle school students’ understandings.

In this context, the project Investigating the Response of Lake Metabolisms and Phytoplankton Biomass to Extreme Events through Automated High-Frequency Measurements was conducted. For this project, a buoy system was located in Lake Eymir, Turkey. Water quality was monitored, and lake metabolism was modeled. Besides, Lake Eymir Education Program (LEEP) was designed to train students in the lake basin as local citizens about lake ecosystems. LEEP consists of in-class activities, fieldwork activities, and meet-a-scientist seminars. In the lesson plans, inquiry-based learning approach was used and connected to Turkish national curricula  of science education. Also, our project partners NETLAKE’s protocols and GLEON’s mobile application were used.

Hence, the purpose of this study was to investigate middle school students’ understandings of lake ecosystems before and after LEEP. Comparing these may reveal the effectiveness of this citizen science project with formal education. Furthermore, their drawings may provide a glimpse into the interpretation of the interaction of ecosystem components. In particular, we addressed the following research question: What are the impacts of LEEP on seventh grade students’ understandings of a lake ecosystem?

In this study, single group pretest-posttest research design was used. The participants were fifty-two seventh grade students (22 female, 30 male) ranging from 12 to 14 years. Students were enrolled in the Science Application course in two different classrooms instructed by different science teachers in a public middle school in the basin of Lake Eymir. Teachers were trained about a lake ecosystem by the first researcher and provided lesson materials before treatment. Within the scope of LEEP, there were 8 indoor activities (2 hours each) at school, 4 outdoor activities at Lake Eymir and Limnology Laboratory (4 hours each), and 2 seminars (1 hour each) that were held for 8 weeks. During all activities, which teachers led, the researchers were there to monitor the procedure and edit the next lesson plans based on the feedback of teachers after each class session. The researchers evaluated implementations by observation checklist to ensure treatment validity. For credibility, the researchers attended all treatment sessions of both classrooms and provided prolonged engagement. The data were gathered qualitatively by using the Lake Ecosystem Drawing Test (LEDT) designed by researchers with a draw-and-explain method that means students are expected not only to draw what a lake ecosystem looks like with the all details but also explain what they drew in order to get a more subtle and nuanced understanding of students both verbally and visually. After necessary ethical approvals for the study, for the setting, each student was provided colorful crayons, pencils, and a blank paper with two instructions on; draw and explain what you drew. Students were informed that there would be no judgment of their artistic drawing skills. For data analysis, inductive content analysis is utilized by two multiple coders; the first researcher is studying science education, and an expert studying freshwater ecosystems. Coders made the coding separately to ensure consistency. They initially labeled what is drawn or explained in students’ papers. If a student had the same code for drawings and explanations, it was accepted as only one code. Codes were revised, and categories were formed by each coder separately. Hereby, every code is connected to a category, and no empty category is left in the data analysis process. Later, the differences of findings were agreed upon by intercoder agreement to establish the data's reliability. The frequencies of codes, subcategories, and categories were given in the study and compared before and after treatment.

Three themes emerged from data analysis of LEDT; biotic components, abiotic components, and interaction between them. The results showed that there is a development in different aspects under these main themes, although students have already learned ecosystem topics in seventh grade science course before treatment. Almost all students perceived a lake ecosystem with more biotic components than preabiotic components in both pretest and posttest, as reported in the literature (Yucel & Ozkan, 2008). Among biotic components, the number of consumers was the highest. The most known fish was carp, while the most known aquatic bird was duck and then cormorant before and after treatment. In the pretest, there were no decomposers, but dead organisms were mentioned. After treatment, students drew and explained the types and names of more species, including decomposers such as fungi and bacteria. Describing an ecosystem just with visible components is a misconception (Sander et al., 2006). Students might think the soil has the function of decomposers before treatment, as shown in the study of Yorek et al. (2010). After treatment, the understandings of invisible abiotic factors, including gases and nutrients, were formed. Students had very limited ecological knowledge, and most students were visualizing the lake ecosystem as a habitat, where there was no interaction or only one-way interaction, as supported by literature (Eilam, 2012; Sander et al., 2006). The only type of interaction students mentioned was feeding relationships between consumers and abiotic-abiotic interactions such as sun warming the lake. After treatment, students’ perception of interaction improved dramatically. Students revealed many complex biotic-biotic, abiotic-abiotic, and biotic-abiotic interactions in a lake ecosystem. Their conceptions of environmental problems such as eutrophication with its reasons and outcomes were also improved after the treatment. The results indicated that Lake Eymir Education Program was effective on students’ understandings of lake ecosystem conception.

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