Metadata are descriptions of data sets that include information such as data quality, keywords, or the spatial or temporal extent of the data set. They provide sufficient information to enable data search, retrieval, transfer, and evaluation. Standardized metadata that can be automatically used by computers without human intervention or interpretation are key components of effective data management, interoperability between distributed data systems, and, most importantly, integrative, interdisciplinary science. Such standardized metadata will reduce the semantic heterogeneity and syntactic incompatibility that currently hinder data management and inter-operability. Unfortunately, many ocean scientists provide either incomplete metadata to allow for automatic data search, retrieval, transfer, or evaluation, or they provide none at all.