Models have served and will continue to serve several important roles in the ARC LTER: (1) examine theoretical constraints on biogeochemistry and community structure. Interactions of CDOM inputs, water residence time, and light exposure to determine DOC photo - degradation (% loss of the initial pool of CDOM, without replacement). (2) compare canopy function among arctic tundra types and link that analysis to eddy covariance data; (3) analyze effects of primary productivity on trophic structure; (4) analyze hydro-logical and biogeochemical connectivity on arctic hillslopes; (5) integrate ARC L TER results to assess responses to climate change; (6) extrapolate biogeochemical properties of ecosystems regionally; (7) predict fish bioenergetic responses to climate change at the individual and population levels , and ( 8 ) simulate recovery from disturbance. Model output from past models. For details and downloads of MBL-GEM and MBL-MEL.