Jerry Monkman / Researchers searching for freshwater mussels in the Ashuelot River, Keene, New Hampshire, USA, September 2006.

Juergen Freund / Charlotte Watson snorkels down to collect sand which may contain polychaete worms, Coral Reef census, Lizard Island, Queensland, Australia, April 2008. Model released

Alex Mustard / Post larval Red Sea sailfin tang (Zebrasoma desjardinii), Gubal Island, Egypt. Strait Of Gubal, Gulf of Suez, Red Sea.

Pete Oxford / Researcher Stephen Spear snorkeling in river, looking for Eastern hellbenders (Cryptobranchus alleganiensis). Cooper's Creek, Chattahoochee National Forest, Georgia, USA, July 2014.

Pete Oxford / Researcher Stephen Spear looking at Eastern hellbender (Cryptobranchus alleganiensis) in plastic bag. Cooper's Creek, Chattahoochee National Forest, Georgia, USA, July 2014.

Pete Oxford / Researchers looking for Eastern hellbenders (Cryptobranchus alleganiensis) Hiwassee River, Cherokee National Forest, Tennessee, USA, July 2014.

Winfried Wisniewski / African Elephant (Loxodonta africana) group using trunks as snorkels while submerged in Chobe River, Chobe National Park, Botswana

Richard Du Toit / African Elephant (Loxodonta africana) group using trunks as snorkels while swimming across the Chobe River, Chobe National Park, Botswana

Shane Gross / The Nature Conservancy volunteer collecting Eelgrass (Zostera marina) shoots with seeds. Part of the largest seagrass bed restoration project in the world led by Virginia Institute of Marine Science....

Shane Gross / The Nature Conservancy scientist Bo Lusk teaching volunteer how to collect Eelgrass (Zostera marina) seeds for seagrass restoration project. Project led by Virginia Institute of Marine Science, Virgin...

Shane Gross / Woman snorkels with Atlantic spotted dolphins (Stenella frontalis) off Bimini, Bahamas.