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Part III. Appendix 1: Metadata and Data DiscoveryTaxonomic names and descriptions are the products of individual scientists whose careers havebeen devoted to describing and understanding relationships among species. Increasingly, these individualsand their colleagues take advantage of DNA or RNA gene sequence data to differentiateamong species and to trace their phylogeography. Species are the units that survive through evolutionarytime and each species is the unique product of its evolutionary history. Specimens of eachspecies are stored in museums for future reference and some may be maintained in culture collections.Species are classified according to their evolutionary relationships using a well-establishedhierarchical system of nomenclature. New species are continually being described and the hierarchicaltree of evolutionary relationships among species, and the associated hierarchical nomenclature,must continually be revised to incorporate new information. For this reason, biological datasystems, unlike physical data systems, require much more attention to metadata. As a minimumquality control and quality assurance measure, the taxonomic authority and the person identifyingthe species should be included with each record and each revised data set.FUTURE CONSIDERATIONSTwo of the most promising methods for translation among multiple controlled vocabularies liewith the use of thesauri and ontologies through the semantic web. In well-structured thesauri withrobust input capabilities, one would be able to load multiple controlled vocabularies. The userscould subsequently query one thesaurus for maximum understanding of the terminology. The useof thesauri should be looked at immediately within the IOOS system.The semantic web is “an extension of the current web in which information is given well-definedmeaning, better enabling computers and people to work in cooperation” 1 . This is accomplishedusing ontologies, which are defined as: The hierarchical structuring of knowledge about things bysub-categorizing them according to their essential (or at least relevant and/or cognitive) qualities” 2 .The main purpose of an ontology is to enable communication between computer systems in a waythat is independent of the individual system technologies, information architectures, and applicationdomain. For example, the Global Change Master Directory’s (GCMD) Earth science keywordsare only one example of a controlled Earth science vocabulary. Other vocabularies exist, and thereis a need to investigate commonality among multiple controlled vocabularies. Ongoing researchand implementation of elements of the semantic web could reveal methodologies to translateamong multiple ontologies and allow the user to search among multiple controlled keywords andthesauri. Further study will be required in the areas of the semantic web and ontologies.1Tim Berners-Lee, James Hendler, Ora Lassila, The Semantic Web, Scientific American, May 20012http://www.dictionary.com; The Free On-line Dictionary of Computing, © 1993-2001 Denis Howe; (1997-04-09)119