Ecological complexity integrates complexity theory and ecosystem function and can provide insights to tackle critical environmental problems. Ecological complexity is not merely describing complicated systems, but complex in the many interacting components controlled by drivers operating across multiple scales. Multiple spatio-temporal scales are needed to understand complex systems. We are interested in understanding these different scales in the terms of biogeochemistry, or biogeochemical complexity. A unifying feature of many LTER sites is biogeochemical complexity. LTER sites including desert, coastal, grassland, and riparian biomes express biogeochemical complexity at many spatio-temporal scales. We wanted to know if we could capture a range of spatio-temporal scales and diversity of biogeochemical structure and processes. In order to address this we used nitrogen inputs and outputs at multiple LTER sites to determine whether the sites were a source or sink for nitrogen. For example, FCE marine coastal site is a sink (~8 MT yr retained) where FCE freshwater site is a source (~170 MT yr released). While these models are course they are a first step to understanding biogeochemical complexity and more information is needed.