<descriptor thcode="62"><thesaurus thcode="62" name="Coastal and Marine Ecological Classification Standard" scope="Categories of ecosystems for coastal, estuarine, and marine environments." creator="FGDC" rights="public domain" date="2017-05-10" codetype="alpha" prefix="cmecs" uri="https://www2.usgs.gov/science/CMECS" tblname="cmecs" root_code="root" contact="pschweitzer"><category><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/></category><altlabel><altlabel>CMECS</altlabel><altlabel>CMECS</altlabel><altlabel>Coastal and Marine Ecological Classification Standard (CMECS)</altlabel><altlabel>Coastal and Marine Ecological Classification Standard (CMECS)</altlabel></altlabel></thesaurus><term thcode="62" code="WC-678" name="Ice" parent="WC-674" scope="Hydroform: Frozen form of water, which is less dense than liquid water; ice floats on the surface of liquid water, sometimes extending into deep water zones. ..."/><bt><term thcode="62" code="WC-674" name="Water Mass" parent="WC-C012" scope="Hydroform Class: The Water Mass Hydroform Class refers to a parcel of water with homogeneous properties (e.g., chemical, physical). ..."/><term thcode="62" code="WC-C012" name="Hydroform" parent="WC-C001"/><term thcode="62" code="WC-C001" name="Water Column" parent="root"/><term thcode="62" code="root" name="CMECS" scope="Coastal and Marine Ecological Classification Standard: Category terms encompassing waters from the head of tide or inland incursion of ocean salinity to the splash zone of the coasts to the deepest portions of the oceans and the deep waters of the Great Lakes."/></bt><nt><term thcode="62" code="WC-687" name="Drift Ice" parent="WC-678" scope="Hydroform Type: Ice that floats freely on the sea surface."/><term thcode="62" code="WC-688" name="Fast Ice" parent="WC-678" scope="Hydroform Type: Ice that is attached to a land mass such as the coast or, in shallow water, the sea floor."/><term thcode="62" code="WC-689" name="Frazil or Grease Ice" parent="WC-678" scope="Hydroform Type: Ice formation that develops when super-cooled water is turbulently mixed, permitting development of small ice crystals which continually fragment and break up without forming ice cover. ..."/><term thcode="62" code="WC-690" name="Ice Field" parent="WC-678" scope="Hydroform Type: Expanse of ice greater in size than an ice floe (=10 kilometers in any dimension)."/><term thcode="62" code="WC-691" name="Ice Floe" parent="WC-678" scope="Hydroform Type: Large floating ice chunk less than 10 kilometers on its longest axis."/><term thcode="62" code="WC-692" name="Pack Ice" parent="WC-678" scope="Hydroform Type: Accumulation of drift ice into a large floating mass, often against a continental shoreline."/><term thcode="62" code="WC-693" name="Pancake Ice" parent="WC-678" scope="Hydroform Type: Thin plaques of compressed ice particles formed by wave action into plates several meters in diameter that float on the sea surface."/><term thcode="62" code="WC-694" name="Polnya" parent="WC-678" scope="Hydroform Type: An area of open, liquid seawater surrounded by ice."/></nt></descriptor>