eLTER (European Long Term Ecosystem Research) is a distributed European in situ based monitoring network operating more than 400 sites across the continent covering all its major biogeographical gradients, therby practicing a whole-system approach. Although its focus is in situ data, through the combination with remote sensing data, value can be added to eLTER results. eLTER practices a distributed data management approach the core of which is a meta data repository and site registry. Particularly through climate related modelling, eLTER is increasingly facing big data challenges.