The existence, sources, distribution, circulation, and physicochemical nature of macroscale oceanic water bodies have long been a focus of oceanographic inquiry. Building on that work, this paper describes an objectively derived and globally comprehensive set of 37 distinct volumetric region units, called ecological marine units (EMUs). They are constructed on...
The Altar Valley is an important working landscape that supports biodiversity and vulnerable species in Pima County, Arizona (Huckelberry 2000). This semi-desert grassland, alluvial valley and 713,807-acre watershed composed of 39 subbasins serves as an aquifer to a portion of southwestern Tucson. This region of Southern Arizona has been identified...