Marine carbon observations (MCOs) are central to understanding the ocean's role in the global carbon cycle and as a major sink for anthropogenic carbon dioxide (CO2). They are also key to global climate governance, informing the Global Carbon Budget and Intergovernmental Panel on Climate Change assessments. Despite their scientific and political relevance, the socio-material conditions of their production remain underexplored. This dissertation addresses this gap by examining how MCOs are produced, and which internal and external factors shape these knowledge production processes. Using an inductive, praxeological, and multi-sited ethnographic approach, the dissertation draws on fieldwork conducted between 2021 and 2024 across laboratories, research and merchant vessels, virtual meetings, and marine research institutes in Brazil and Germany. It analyses four interconnected empirical cases: deep-sea observations aboard a research vessel, transnational intersectionality in work and research at sea, socio-material processes of (de-)stabilisation in MCO, and an autoethnographic marine expedition. The findings show that MCOs are relational socio-material achievements rather than linear technical outputs. Observations are co-produced by human and more-than-human forces, including scientists, technicians, sensors, seawater, and infrastructures. Their stabilisation depends on communication, interpersonal relations, and data availability, while funding shortages, borders, and climate change impacts contribute to destabilisation. In addition, sensory, embodied, and experiential forms of knowledge - including intuition and emotions -shape everyday scientific practice and insight. Marine knowledge production is further structured by transnational intersectional hierarchies and micropolitics, with gender, age, class, ethnicity, and physical appearance influencing access, credibility, and safety at sea. Conceptually, the dissertation develops the framework of Intra-active Observation Assemblages (IOA) to capture how situated practices, embodiment, affect, inequality, and more-than-human forces co-produce policy-relevant marine knowledge. It contributes to the Sociology of Knowledge, Science and Technology Studies, feminist and new materialist approaches, while methodologically extending multi-sited ethnography to mobile, transnational, and more-than-human field sites. The findings further highlight how borders, funding structures, and institutional hierarchies shape scientific cooperation, with implications for more transparent, diverse, and inclusive science-making at sea.
Ramona Hägele (2026) studied this question.