<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="BC-485" name="Diatom Maximum Layer" parent="BC-415" scope="Biotic Group: Relatively thin layer dominated by diatoms at depth in the water column. Layers of high diatom density generally form in the surface mixed layer and have also been found at deep subsurface maxima. These are associated with nutrient or temperature maxima."/><bt><term thcode="62" code="BC-415" name="Diatom Phytoplankton" parent="BC-387" scope="Biotic Subclass: Waters dominated by Diatom Phytoplankton, single-cell algae that circulate passively or sink in the water column. ..."/><term thcode="62" code="BC-387" name="Phytoplankton" parent="BC-384" scope="Biotic Class: This class includes areas of floating or suspended microscopic algae that are capable of photosynthesis. ..."/><term thcode="62" code="BC-384" name="Planktonic Biota" parent="BC-C002" scope="Biotic Setting: Planktonic Biota includes biota that drift, float, or remain suspended in the water column in aggregations that are big enough to be (a) detected by the human eye (or with mild magnification) or (b) sampled with a fine-plankton net. ..."/><term thcode="62" code="BC-C002" name="Biotic" 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>