<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="AS-002" name="Estuarine" parent="AS-C000" scope="System: The Estuarine System is defined by salinity and geomorphology. ..."/><bt><term thcode="62" code="AS-C000" name="Aquatic Setting" 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="AS-007" name="Estuarine Coastal" parent="AS-002" scope="Subsystem: The Estuarine Coastal Subsystem extends from the supratidal zone at the land margin up to the 4 meter depth contour in waters that have salinity greater than 0.5 (during the period of average annual low flow). ..."/><term thcode="62" code="AS-008" name="Estuarine Open Water" parent="AS-002" scope="Subsystem: The Estuarine Open Water Subsystem includes all waters of the Estuarine System with a total depth greater than 4 meters, exclusive of those waters designated Tidal Riverine Open Water. ..."/><term thcode="62" code="AS-009" name="Estuarine Tidal Riverine Coastal" parent="AS-002" scope="Subsystem: The Estuarine Tidal Riverine Coastal Subsystem includes the most upstream region of the estuary, in those areas between MHHW to the 4 meter depth contour below MLLW in waters that (a) can be regularly influenced by tides and (b) where salinity is below 0.5 during the period of annual low flow. ..."/><term thcode="62" code="AS-010" name="Estuarine Tidal Riverine Open Water" parent="AS-002" scope="Subsystem: The Estuarine Tidal Riverine Open Water Subsystem includes tidal freshwater areas with a salinity of &lt;0.5 and a depth of greater than 4 meters at MLLW. ..."/></nt></descriptor>