<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-657" name="Cold Core Ring" parent="WC-639" scope="Hydroform Type: An eddy that forms when a boundary current meander pinches off and closes, trapping a parcel of colder water in a surrounding ring of warmer water. ..."/><bt><term thcode="62" code="WC-639" name="Mesoscale Eddy" parent="WC-627" scope="Hydroform: A rotational feature that (a) breaks off of an ocean gyre or large current (such as the Gulf Stream) and (b) persist autonomously for some period (from days to months) at sizes of 20 kilometers to 500 kilometers. ..."/><term thcode="62" code="WC-627" name="Current" parent="WC-C012" scope="Hydroform Class: Water that is undergoing coherent mass movement, either as laminar or turbulent flow, relative to surrounding waters and fixed structural, landform or geologic features. ..."/><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></descriptor>