. . . . . . . . . "Concentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the surface ice [dissolved plus reactive particulate . "SDN:P01::ICNHXX01" . "accepted"@en . . "NH4_ice_ . . . . "Amount (quantity or mass) of the specified analyte in a unit volume of a melted ice sample from anywhere on the Earth's surface filtered through GF/F."@en . . . . . . . .