MarineGEO research addresses how and why biodiversity is changing, how that influences ecosystem processes important to people, and how to use this knowledge to better inform management for resilient marine ecosystems. The research complements existing ocean observing programs but fills a critical void with its unique focus on biodiversity, seafloor (benthic) communities, nearshore areas where biodiversity and people are concentrated and interact most, and standardized methods that facilitate rigorous global comparative analysis. MarineGEO is also unique in its focus on collaborative partnerships and on coordinated experiments as a powerful means for identifying the causes and consequences of environmental and biodiversity change. MarineGEO focuses on sediment, marine vegetation, and reef (coral, rock, oyster) as the key habitats comparable across geographic regions. The MarineGEO core research plan consists of a set of standardized measurements of status, trends, and control of nearshore biodiversity, conducted regularly (generally annually) across partner sites, providing a powerful network for studying local and global change. The Smithsonian’s TMON takes responsibility, in consultation with partners, for coordination of MarineGEO activities; curation of collections (in coordination with depositories in host countries); management of a central database accessible to partners; sponsorship of synthesis and training activities; and central outreach. The main criterion for partnership in MarineGEO is individual and institutional commitment to accomplish common research goals. This involves local leadership and in-kind contributions of staff time and expertise, and infrastructure. The set of specific protocols considered acceptable for particular components will evolve to some extent through time; at any given time the standard set is defined by mutual agreement of the MarineGEO community.