Urban ecology is evolving as the scientific base grows and new concerns of urban partners emerge. In the Baltimore Ecosystem Study (BES), both of these drivers are at work. Examples of core, ongoing research include flow and biogeochemistry of streams draining watersheds of differing degrees of urbanization, permanent plot studies of biogeochemistry, physical environment, and biodiversity, micrometeorology and surface-atmosphere fluxes, assessment of social attitudes and environmentally relevant actions and organization, household characteristics and decision making, social differentiation, and historical analysis of development of current environmental inequities. New integrative themes include the social ecology of residential lawns, the development of urban tree canopy goals, the relationship of property regimes, vegetation structure, and property values, the restoration of small city and suburban watersheds, fine scale relationships of ground water to urban structure, and economic choice modeling for households and firm location. New data streams on land cover change are positioned to advance the integration of social and biophysical processes. The development of BES research themes parallels the establishment of sustainability plans in the City of Baltimore, Baltimore County, and the State of Maryland. This emerging perspective on urban sustainability contrasts with the traditional ideal of structuring urban form, which has dominated urban form since the 19th century, to facilitate flows of economically determined resources and production of sanitary conditions. BES has established a formal relationship with principals in these sustainability efforts, and we are exploring new, joint research questions reflecting both scientific and practical motivations. In particular future efforts will bolster research on climate change and its relationship to social and land use scenarios. Contributing members of BES will be listed on the poster.