Daniel Beltrá on the job in the Southern Ocean.


Oil-soaked pelicans huddle at a bird rescue and research center in Fort Jackson, La., this past summer, victims of the BP oil disaster in the Gulf of Mexico. The center was one of many locations conservation photographer Daniel Beltrá visited to document the oil's impacts on the fragile gulf ecosystem.


Beltrá took thousands of pictures of the BP oil disaster in the Gulf of Mexico, many of them from aboard a small airplane. This image, taken in May, shows oil streaked across the water's surface in the area where the Deepwater Horizon wellhead sank, creating the worst spill in U.S. history.


Deforestation has been used to create new palm-oil plantations like this one Beltrá shot from the air over Kuala Kuayan in Indonesia. Felled trees litter the scene. "I don't pretend to be objective - I try to be fair," Beltrá says. "I hope that people see what I see and feel they need to do something. But I don't want to tell them what."


A road is the only thing separating rain forest and recently logged and burned land in Jambi province, Indonesia, in this image Beltrá took in 2009. Lots of photographers are doing amazing work showing how beautiful nature is, he says, "but I feel almost as if there's no time for that right now. There're issues that are so much more urgent and need to be exposed."


Beltrá spotted this river boat stuck on a sand bank east of Barreirinha, Brazil, in 2005 during one of the worst droughts ever recorded in the Amazon. Is climate change the culprit? "It's very easy to convince a certain segment of society on certain issues that are probably much closer to my way of thinking," Beltrá says, "but I'm more interested in convincing the other side."


A cattle ranch in Agua Boa, Mato Grosso state, in Brazil, stretches across a logged section of the Amazon basin in this arresting picture Beltrá took in 2008. Greenpeace says ranchers are destroying rain forests here to feed appetites in rich nations thousands of miles away.


A logger lumbers an Afromosia tree into planks with only a chain saw at an artisanal logging operation near Kisangani, Democratic Republic of Congo, in 2009.


The placid surface of the Ross Sea, in the Southern Ocean, reveals the size of an iceberg beneath the surface of the water in this picture Beltrá took during an expedition in 2007.


Beltrá photographed Kawali Aweresese, an Enawene Nawe tribe member, in Mato Grosso state in Brazil last year. The tribe's traditional fishing method of building barrages is threatened by plans to erect 86 dams along the Juruena River, part of Brazil's Growth Acceleration Program.


A small island in Lake Mai-Ndombe is revealed through the cloud cover in the central region of the Democratic Republic of Congo, May 14, 2009.