While famous for its expanses, the Grand Canyon's minutiae afford wonder in species and entire genera found nowhere else on Earth. Nestled in moist recesses amid massive stone chasms, the Canyon's seeps, springs, and caves form havens where eons of isolation have allowed processes of speciation to yield life forms as lovely as white-flowering redbud trees and as obscure as eyeless cave-limited millipedes.

Though each seep, spring, and cave ecosystem differs from the next, common to all is water originating from regional aquifers and watersheds extending miles north and south of the Canyon's rims. And it's here, on public lands atop those aquifers and not far from Grand Canyon National Park's boundary, that a uranium-mining boom now threatens the water that brings life to an international treasure's biological diversity and provides drinking water to millions of Americans in the Colorado River.

Public lands surrounding Grand Canyon National Park contain some of the highest concentrations of uranium deposits in North America. Spikes in uranium prices in recent years have caused an explosion of new mining claims and exploration on those lands -- and spurred efforts to reopen previously abandoned mines. Thousands of new claims have been staked, dozens of exploration drilling projects have been proposed, and at least three mines -- two north (the Arizona 1 and Pinenut mines) and one south (Canyon mine) of the Grand Canyon -- are targeted for reopening.

New uranium development has the potential to harm species, ecosystems, water quality and tourism in and around Grand Canyon National Park. Aquifer contamination, were it to result from new uranium development, could impact municipal uses of the Colorado River in addition to special status species and biologically rich seep, spring, and riparian ecosystems within the park.

Help the Center for Biological Diversity urge the Obama administration to enact a new mineral withdrawal -- using the Secretary of the Interior's unique authority for doing so -- that would put an end to our ongoing litigation to protect the Grand Canyon and afford surrounding watersheds the protections they deserve.