Understanding the role of catchment properties is crucial for anticipating soil-derived dissolved organic carbon (DOC) export to aquatic systems, especially under changing climatic conditions. We present natural variations in DOC concentrations and fluxes in eight catchments differing in size (3 – 300 km 2 ), morphology (very steep to flat), and landscape type (Patagonian steppe, forest and peatland) along a steep precipitation gradient in remote pristine southern Patagonia, Chile. Discharge, precipitation and water chemical parameters were used to differentiate the mechanisms controlling DOC release in different catchment types. The results show large differences between catchments in terms of DOC concentrations (2 - 47 mg L -1 ) and fluxes (1 to 44 tons km -2 yr -1 ) but also in response to changes in precipitation. Small steep and forested catchments are the most reactive in terms of DOC export; specifically, changes in discharge produce fast, high and exponential increases in DOC release. DOC leaching by surface run-off through the organic soil layer is the main source of DOC during high precipitation events, and steep catchments became short-term hotspots for DOC export. In the flat catchments of the Patagonian steppe, the generally lower precipitation rates favour temporal accumulation of DOC in soils, and seasonal high discharge events produce one-off increases in DOC fluxes. Although peatlands constitute a large and continuous source of DOC export, the influence of discharge variation on DOC fluxes in peatland-dominated catchments appears to be low, despite the large carbon pools. Thus, in DOC catchments with similar precipitation regimes, morphology is the dominant factor determining ecosystem responses, where the steepest catchments show the highest sensitivity to rain events in terms of DOC export. Morphology and hydrological buffer capacity rather than the size of the carbon pools or precipitation intensity determine the export of DOC from catchments during strong rain events.