Use of standardized keyword vocabularies is essential to interoperability of cross discipline resource catalogs.This page provids links to some existing keyword schemes.
Ontology-based
Interpretation of Keywords for Semantic Search (not a keyword list, but very
relevant.)
NASA
Global change master directory (GCMD) science keywords
National
geophysical data center discussion of Keywords
Marine metadata
initiative vocabularies
DLESE
Controlled
vocabularies for completing certain metadata fields