Secretary of the Interior Ken Salazar will leave his post at the end of March. Salazar, a former Colorado senator, served as interior secretary for all of President Obama’s first term, and spent much of his time focused on energy issues, but the 2010 BP oil spill undermined many of his most ambitious plans. His departure means that Obama’s cabinet, which has already been criticized for a lack of diversity among recent nominees, may now be even less diverse in his second term. Salazar is of Hispanic descent. A replacement has not yet been announced.