ALT A shark swims next to a shoal of fish in crystal clear blue water above a sandy bottom.

ALT A grey shark swims next to a school of silver fish in crystal clear water with a sandy bottom.

ALT A yellow crinoid with black stripes on a red algae encrusted rock.

ALT A red anemone with white spots.

ALT An up close photo of a blue giant clam siphon.

ALT A tiny loggerhead turtle emerges from its shell on a sandy beach.

ALT A manta ray swims towards the photographer swimming through blue ocean water surrounded by black and silver fish.

ALT A school of silver fish form a ball in the water column with sunlight streaking through the surface of the ocean.

ALT Two clownfish in a purple anemone with white tentacles.

ALT A coral reef and reef fish.

ALT A splitshot of a mangrove tree with a blue sky background above water and light blue, clear water with roots subsurface.

ALT A purple and tan sea fan is surrounded by yellow fish and blue water.

ALT A yellow green leafy seadragon in the water column.

ALT A reef with colorful acropora corals, many orange anthias and purple anthias, and clear blue water. There are also some other species of corals and fish as well.

ALT From the California Academy of Sciences: "Photograph of fossil diatoms collected in Pt. Reyes National Seashore in Marin County, California, and arranged on a microscope slide in 1968 by A.L. Brigger."

ALT A school of blue and yellow fish with white and black markings swim just below the ocean surface.

ALT Dr. Sylvia Earle SCUBA dives while surrounded by silver fish.

ALT A humpback whale gently pushes her calf to the surface for a breath.

ALT A turtle hatchling emerging from its shell.

ALT A whale shark and some silver fish swim just below the ocean surface.

ALT A diving Dr. Sylvia Earle gestures to a school of yellow fish.

ALT A turtle rests on a rocky/sandy ocean bottom.

ALT A green sea turtle swims through blue water.

ALT A marine iguana feeds on some algae underwater.

ALT A turtle swims above sand and rocks in the ocean.

ALT A whale shark swims in open blue water.

ALT A Hawaiian monk seal floats in clear blue water.

ALT A humpback whale gently pushes her calf to the surface for a breath.

ALT A black tip reef shark cruises the shallow coral reefs of the Olowalu Reef Hope Spot in Hawaii.

ALT A large school of silver fish in blue ocean water.

ALT A hammerhead shark swims through blue water surrounded by dark grey fish.

ALT A hammerhead shark swims overhead with the bright blue ocean surface in the background.

ALT An orange fish with bright blue stripes atop some pink coralline algae.

ALT A school of yellow fish with Dr. Sylvia Earle diving in the background.

ALT A sea turtle glides through crystal clear ocean water.

ALT A green sea turtle peeks from a hiding place between rock and red coral.

ALT A colorful coral reef surrounded by small blue fish.

ALT Dolphins play in a wave at sunset.

ALT Dr. Sylvia Earle scuba dives above a school of yellow fish in clear blue water.

ALT A whale shark skimms the surface.

ALT Orange fish surround a coral reef.

ALT A marine iguana hanging on to an algae covered rock underwater surrounded by black fish.

ALT Small brown and blue fish swim around a coral outcropping.

ALT A yellow triggerfish with blue stripes swims above fuzzy green algae.

ALT Humpback whale flukes at the ocean surface with ice shelves in the background.

ALT A green sea turtle in shallow, clear ocean water.

ALT A school of yellow fish with black stripes swim in front of branching coral. The ocean surface is visible above.

ALT A clownfish swims under a large purple and cream anemone.

ALT A pod of dolphins swims in clear blue ocean water.

ALT Looking down on a colorful coral reef with small blue fish.

ALT An orange, white, and brown sea star in some algae.

ALT An orange and brown sea star on rocky substrate.

ALT A purple, orange, and red sea star on algae.

ALT Two orange sea stars in kelp.

ALT A school of fish swim above a coral reef.

ALT A basking shark cruises just below the ocean surface.

ALT A cuttlefish in blue water above a sandy bottom with a coral reef in the background.

ALT A green meadow of seagrass with corals in the background and the blue surface of the ocean above.

ALT A manta ray swims through clear water.

ALT A whale shark swims past a group of divers.