Ecosystems research became a year-round commitment at the MBL in 1962 with the founding of the Systematics-Ecology program, under the direction of Melbourne R. Carriker. In 1975, the MBL's Ecosystems Center was established, with George Woodwell as director. The original research focus was on the global carbon cycle, an emphasis maintained today. The Ecosystems Center has a year-round staff of more than 40 scientists who study a variety of ecosystems and their responses to human activities and environmental changes. The center is located in Woods Hole yet has a global reach, with active research sites in the Arctic tundra; in forest, coastal and marine sites in New England, Sweden and Brazil. The Ecosystems Center is home to two of the 26 U.S. Long Term Ecological Research (LTER) sites: Toolik Lake, Alaska; and Plum Island, Massachusetts. Scientists in the Ecosystems Center study the effects of forest clearance and land-use change on atmospheric chemistry, watershed processes and coastal ecology, the global-scale anthropogenic enrichment of the nitrogen cycle, and ecosystem responses to global warming. The interim director of the Ecosystems Center is Anne Giblin. Former directors of the Center who are still active on the scientific staff are Jerry Melillo, who studies the biogeochemistry of terrestrial ecosystems, and John Hobbie, a microbial ecologist. The Ecosystems Center is founded on a vision of collaborative, interdisciplinary science; shared lab facilities and instrumentation; and a long-term, large-scale, systems-wide view of ecosystem processes.