Physical, Chemical, and Biological Connectivity of Water Bodies in a Watershed Context – Lessons from Naked Watersheds

English Abstract:

The connectivity of water bodies (streams, wetlands, lakes, etc.) is an important underpinning of terrestrial/aquatic ecosystem processes as well as water quality dynamics in space and time. In temperate watersheds, the study of the hydrologic, chemical, and biological connectivity of water bodies can be significantly complicated by land cover, complex hydrogeology, and management practices. Here we use a hydrologically-based framework to characterize the connectivity of water bodies through quantification of the frequency, magnitude, and duration of measured connections in a watershed with no vegetation cover and very little groundwater – the McMurdo Dry Valleys, Antarctica. The frequency, magnitude, and duration of connections of glaciers to lakes, via meltwater streams are well-quantified over this period, from an extensive stream gauging network. The connectivity and disconnectivity (periods of no flow) have significant influences on stream diatom and algal communities. In the past decade, we have observed increased connectivity of glaciers to soils and lakes outside of stream channels as new parts of the landscape are melting and thawing and providing new water that flows toward valley-bottom lakes.