This study explored and documented students' responses to opportunities for collective knowledge building and collaboration in a problem-solving process within complex environmental challenges and pressing issues with various dimensions of knowledge and skills. Middle-school students ("n" =?16; age 14) and high-school students ("n"?=?16; age 17) from two Singapore public institutions participated in an environmental science field study to experience knowledge integration and a decision-making process. Students worked on six research topics to understand the characteristics of an organic farm and plan for building an ecological village. Students collected and analysed data from the field and shared their findings. Their field work and discussions were video-recorded, and their reflective notes and final reports were collected for data coding and interpretation. The results revealed that throughout the study, students experienced the needs and development of integrated knowledge, encountered the challenges of knowledge sharing and communication during their collaboration, and learned how to cope with the difficulties. Based on research findings, this study further discusses students' learning through a collaborative problem-solving process, including the interdependence of knowledge and the development of mutual relationships such as respect and care for others' knowledge and learning. (Contains 1 note, 3 tables, and 2 figures.)