Interior Secretary Ken Salazar will soon leave his post, the White House has confirmed.

Salazar will depart in March, according to an official at the Interior Department and a senior administration official, both who were granted anonymity to provide additional details.

Interior Secretary Ken Salazar. (Carolyn Kaster - AP)

Salazar, a former Colorado senator whose family is of Hispanic descent, has served at Interior for President Obama's entire first term.

"I want to thank Ken for his hard work and leadership on behalf of the American people," President Obama said in a statement. "As the Secretary of the Interior, Ken has helped usher in a new era of conservation for our nation’s land, water, and wildlife."

His exit means that Obama's cabinet, which has already come under some fire for lacking diversity in its recent nominees, will lose a little bit more diversity -- at least temporarily.

Another Latino cabinet member, Labor Secretary Hilda Solis, resigned last week, and two other top women -- Secretary of State Hillary Clinton and Environmental Protection Agency head Lisa Jackson -- are both on their way out.

It's not clear who will be chosen to succeed Salazar. Interior secretaries generally come from west of the Mississippi River. Former Washington governor Chris Gregoire (D), former congressman Norm Dicks (D-Wash), and former North Dakota senator Byron Dorgan (D) have all been mentioned as potential appointees, as have former Wyoming Gov. Dave Freudenthal (D) and Deputy Interior Secretary David Hayes.

Other possible, but perhaps less likely contenders, are Rep. Raul Grijalva (D-Ariz.), an outspoken liberal backed by environmentalists, and Office of Personnel Management director John Berry, who is openly gay and who would be the first openly gay cabinet secretary.  Berry, 53, was a deputy secretary at Interior during the Clinton administration and led the National Fish and Wildlife Foundation and the National Zoo before Obama tapped him to run his personnel agency.

(For more on a Cabinet in transition, be sure to check out the Post's interactive graphic.)

Salazar spent much of his tenure as Interior secretary focused on energy issues, including promoting renewable energy, as well as dealing with the disastrous BP oil spill in the Gulf of Mexico.

He promoted solar projects on public lands by identifying “solar energy zones” where there were fewer conflicts between development and vulnerable species or habitat. And he pressed for offshore wind development along the East Coast, suggesting that the area could become a prime site for future energy production.

The 2010 BP spill undermined some of his most ambitious plans, forcing him to spend several months working to cap the leaking Macondo well and overhaul the troubled Minerals Management Service.

Salazar addressed conflicts of interests embedded in federal oversight of offshore oil and gas drilling by creating two separate entities -- the Bureau of Ocean Energy Management and the Bureau of Safety and Environmental Enforcement — to monitor offshore energy exploration.

Oil and gas officials, as well as their allies in Congress, criticized Salazar for imposing a temporary moratorium on drilling in the Gulf of Mexico in the wake of the oil spill. But oil and gas drilling there has now returned to pre-spill levels, spurred by high oil prices.

Salazar encountered stiff opposition to his efforts to create new protected areas on public land, including wilderness. In late 2010, Salazar proposed giving interim federal protection to areas with wilderness protections know as “wild lands,” a policy he was forced to abandon when House Republicans included legislative language overturning it.

While he and his senior deputies privately lobbied the president to designate some ecologically-valuable areas as national monuments under the 1906 Antiquities Act, Obama only designated a few small national monuments, all of which had historic or cultural attributes.

This post was updated at 11:48 a.m.