Baltimore Ecosystem Study Institute of Ecosystem Studies

2014 BES Annual Meeting Presentation and Poster Abstracts

Tracking Evolution of Urban Biogeochemical Cycles: Past, Present, Future
Kaushal, Sujay
Co-Authors: William McDowell, Wilfred Wollheim, Julia Gorman, Tamara Newcomer Johnson, Michael Pennino, Paul Mayer, and Kenneth Belt

Abstract: The concept of "urban evolution" has been recently proposed and explored in a special issue of the journal Biogeochemistry. The built environment often changes quickly in response to human activities, thus contributing to an urban evolution of structure, function, and ecosystem services over time. Depending upon management, these changes can be rapid losses of ecosystem functions/services or gains towards restoration over time. We explore urban evolution at the BES LTER site through empirical examples such as: (1) land development and nitrogen inputs within the Baltimore metropolitan region over half a century, (2) watershed drainage by different forms of stormwater management over decades, (3) accelerated chemical weathering of urbanized watersheds over decades, and (4) salinization of freshwater across urbanizing landscapes over a century. We also synthesize concepts relevant to studying urban evolution of landscapes, infrastructure, and aquatic systems at the BES LTER site. Some of these include: (1) urban watersheds have challenged our whole notion of the "watershed approach" due to complex hydrologic boundaries and flow paths over time (2) the urban hydrologic cycle evolves due to changing infrastructure and human water use over time (3) importance of extending research beyond individual sites using an urban watershed continuum approach over space and time (4) salinization as a potential tracer of watershed urbanization over time (5) accelerated weathering of concrete and construction materials contributing to an "urban karst" over time. Urban biogeochemical cycles exert a major influence on the elemental composition of the Earth's surface from local to global scales over time. There is a need for a new research agenda tracking the evolution of urban biogeochemical cycles as land development proceeds and infrastructure/management changes so we can better evaluate potential losses in ecosystem services, set realistic watershed and river restoration goals, and formulate effective environmental policy for Earth's growing urban population. A potential research agenda at the BES LTER site will be discussed.