Synchronous population fluctuations among spatially separate populations have been widely observed in many taxa, at a variety of distances and scales. Moran effects, where populations are synchronized by a correlated environmental variable, are one of the primary mechanisms cited to cause spatial synchrony in populations. This thesis investigated patterns in synchrony of large-scale metapopulations in both marine and terrestrial environments. Despite their importance, both temporal changes in synchrony and geographic patterns in synchrony have, to date, been little explored. I investigated patterns of synchrony in plankton in the North Sea, before and after its regime shift. Results showed that patterns of synchrony in plankton and in sea surface temperatures changed over the regime shift period in the North Sea. Changes were not explained by changes in abundance and varied among taxa, indicating the potential for climate-change impacts on synchrony. I then explored geographic patterns of synchrony in primary productivity globally, including marine and terrestrial systems, and determined to what extent Moran effects may be driving these patterns. I found a significant spatial structure to synchrony in both phytoplankton and terrestrial vegetation globally, and that primary production is highly synchronized over large regions. There was considerable variation in the ability of Moran effects to explain these regions of synchrony. In general, synchrony in terrestrial vegetation was better explained by Moran effects than synchrony in marine phytoplankton. Additionally, results demonstrated that synchrony of primary productivity and its geography are time-scale-specific.