<descriptor thcode="61"><thesaurus thcode="61" name="Marine Realms Information Bank (MRIB) keywords" scope="Theme keywords from the former Marine Realms Information Bank, focusing on characteristics of coasts and oceans, processes acting on them, and human concerns about them." creator="U.S. Geological Survey" rights="Public domain" date="2016-09-07" codetype="number" prefix="mrib" tblname="mrib" nonpref="mribnp" relterm="mribrt" root_code="1" contact="aallwardt"><category><term thcode="25" code="27" name="types" parent="26" scope="Terms are types of things rather than named instances"/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="27" name="types" parent="26" scope="Terms are types of things rather than named instances"/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/></category><altlabel><altlabel>MRIB keywords</altlabel><altlabel>MRIB keywords</altlabel><altlabel>Marine Realms Information Bank keywords</altlabel><altlabel>Marine Realms Information Bank keywords</altlabel></altlabel></thesaurus><term thcode="61" code="284" name="polar ecosystems" parent="282" scope="used for high-latitude ecosystems threatened by warming and pollution."/><uf><usefor name="tundra ecosystems"/></uf><bt><term thcode="61" code="282" name="fragile ecosystems" parent="269" scope="used for ecosystems that are sensitive to environmental changes."/><term thcode="61" code="269" name="environment" parent="268" scope="used for issues related to the interactions of humans or other organisms with their physical and biological surroundings."/><term thcode="61" code="268" name="hot topics" parent="1"/><term thcode="61" code="1" name="Marine Realms Information Bank (MRIB) keyword categories"/></bt></descriptor>