We report on a demonstration system for text mining of literature in marine science and related disciplines. It automatically extracts variables (“CO2”) involved in events of change/increase/decrease (“increasing CO2”), as well as co-occurrence and causal relations among these events (“increasing CO2 causes a decrease in pH in seawater”), resulting in a big knowledge graph. A web-based graphical user interface targeted at marine scientists facilitates searching, browsing and visualising events and their relations in an interactive way.