NEW REEF

A new coral recruit, with a single polyp just 0.07 inch (1.8 millimeters) wide, has settled on the edge of an encrusting seaweed (a crustose coralline alga) overgrowing another alga ( Peyssonnelia sp.)....[More]

NEW REEF

A new coral recruit, with a single polyp just 0.07 inch (1.8 millimeters) wide, has settled on the edge of an encrusting seaweed (a crustose coralline alga) overgrowing another alga (Peyssonnelia sp.). Several colonies of tunicates, resembling fried eggs and connected by fine threadlike stolons, also grow nearby, as does a finely branching red seaweed. Two white polychaete worm tubes also emerge through one of the encrusting seaweeds.  [Less] [Link to this slide]

METAMORPHOSIS

A recently metamorphosed coral recruit, about 0.03 inch (0.84 millimeter) wide, grows on a settlement tile. Corals, like most marine animals, have a larval stage that disperses though the water column....[More]

METAMORPHOSIS

A recently metamorphosed coral recruit, about 0.03 inch (0.84 millimeter) wide, grows on a settlement tile. Corals, like most marine animals, have a larval stage that disperses though the water column. When it finds suitable cues, this larva will settle to the bottom, and metamorphose into a polyp with a central mouth. Most reef-building corals also contain symbiotic, single-celled algae called zooxanthellae inside them, which allows the coral–zooxanthellae combination to function like plants, transforming light into chemical energy. Here, we see some of these zooxanthellae, appearing as tiny brown spots, within the young coral.  [Less] [Link to this slide]

NEW POLYP

After metamorphosing into a new polyp, a young coral will start to develop its skeleton. Here, through the transparent soft tissue of the polyp, which is 0.045 inch (1.16 millimeters) wide, we see the coral's skeleton, known as the corallite....[More]

NEW POLYP

After metamorphosing into a new polyp, a young coral will start to develop its skeleton. Here, through the transparent soft tissue of the polyp, which is 0.045 inch (1.16 millimeters) wide, we see the coral's skeleton, known as the corallite. Symbiotic zooxanthellae, single-celled algae inside the coral's cells, are also clearly visible as tiny dark balls throughout much of this coral.  [Less] [Link to this slide]

NEW RECRUIT

With its short tentacles extended, a new coral recruit, just 0.025 inch (0.65 millimeters) wide, grows among a fine filigree of hydroids (a distant colonial animal relative of corals) on the border of two seaweeds, a crustose coralline alga and a burgundy crust alga ( Peyssonnelia sp.)....[More]

NEW RECRUIT

With its short tentacles extended, a new coral recruit, just 0.025 inch (0.65 millimeters) wide, grows among a fine filigree of hydroids (a distant colonial animal relative of corals) on the border of two seaweeds, a crustose coralline alga and a burgundy crust alga (Peyssonnelia sp.).  [Less] [Link to this slide]

NEW COLONY

A small coral colony, composed of just three polyps some 0.05 inch (1.3 millimeters) wide, grows on top of some small polychaete worms and a sparse "turf" of a red alga, which in turn have colonized a surface of crustose coralline algae that has died and is becoming covered by a microscopic green alga....[More]

NEW COLONY

A small coral colony, composed of just three polyps some 0.05 inch (1.3 millimeters) wide, grows on top of some small polychaete worms and a sparse "turf" of a red alga, which in turn have colonized a surface of crustose coralline algae that has died and is becoming covered by a microscopic green alga.  [Less] [Link to this slide]

GROWING COLONY

A young coral colony (belonging to the family Poritidae), at the three-polyp stage and 0.04 inch (0.95 millimeter) wide, grows on an experimental settlement tile amidst even smaller spiral tube worms ( Spirorbis sp.)....[More]

GROWING COLONY

A young coral colony (belonging to the family Poritidae), at the three-polyp stage and 0.04 inch (0.95 millimeter) wide, grows on an experimental settlement tile amidst even smaller spiral tube worms (Spirorbis sp.).  [Less] [Link to this slide]

OVERCROWDING

Space on reefs is a tight commodity, even on the mostly dark undersides of corals and on small crevice walls. The undersides of settlement tiles simulate this microhabitat, just 0.4 inch (11 millimeters) wide, allowing for the examination of lethal competition among diverse plant and animal species....[More]

OVERCROWDING

Space on reefs is a tight commodity, even on the mostly dark undersides of corals and on small crevice walls. The undersides of settlement tiles simulate this microhabitat, just 0.4 inch (11 millimeters) wide, allowing for the examination of lethal competition among diverse plant and animal species. Here, pink crustose coralline algae ("pink paint") is being overgrown by a species of bryozoan (a group of colonial animals that are physically smaller though morphologically more complex than corals) that is equipped with spiny appendages, which in turn is being overgrown by a white, meshed sponge. Another orange bryozoan species appears poised to enter the fray from the lower right corner.  [Less] [Link to this slide]

HEAVY GRAZING?

An experimental settlement tile, attached to the bottom of a back reef habitat at Palmyra Atoll. The pink coloration on the reef and the tile (sometimes called "pink paint" or "reef cement") is crustose coralline algae, which becomes especially common in places where seaweeds are heavily grazed by herbivores (such as this small school of convict tang, Acanthurus triostegus ) or limited by other extreme ecological conditions....[More]

HEAVY GRAZING?

An experimental settlement tile, attached to the bottom of a back reef habitat at Palmyra Atoll. The pink coloration on the reef and the tile (sometimes called "pink paint" or "reef cement") is crustose coralline algae, which becomes especially common in places where seaweeds are heavily grazed by herbivores (such as this small school of convict tang, Acanthurus triostegus) or limited by other extreme ecological conditions.  [Less] [Link to this slide]

LIMPETING ALONG

The keyhole limpet ( Emarginula sp.) subsists on algae and is a relative of the snail. This specimen, just 0.18 inch (4.5 millimeters) long, cruises across a red encrusting seaweed ( Peyssonnelia sp., aka burgundy crust alga)....[More]

LIMPETING ALONG

The keyhole limpet (Emarginula sp.) subsists on algae and is a relative of the snail. This specimen, just 0.18 inch (4.5 millimeters) long, cruises across a red encrusting seaweed (Peyssonnelia sp., aka burgundy crust alga).  [Less] [Link to this slide]

SEA SLUG

An undescribed nudibranch sea slug ( Eubranchus sp.) about 0.08 inch (two millimeters) long, crawls over a bryozoan colony on an experimental settlement tile....[More]

SEA SLUG

An undescribed nudibranch sea slug (Eubranchus sp.) about 0.08 inch (two millimeters) long, crawls over a bryozoan colony on an experimental settlement tile. Many nudibranchs in this group tend to eat cnidarians such as hydroids, sea anemones and corals. Rather than being sensitive to their prey's stingers, however, these slugs consume without triggering the stinging structures, and then co-opt and deploy them in their own bodies as a defensive mechanism.  [Less] [Link to this slide]

TINY CRABS

An unidentified small crab about 0.08 inch (two millimeters) wide, possibly Liocarpilodes sp., found on the undersides of settlement tiles. Studying the tiles under a microscope, researchers sometimes find one bright, shiny compound eye looking back at them from a small hole in the surface where the crabs take refuge....[More]

TINY CRABS

An unidentified small crab about 0.08 inch (two millimeters) wide, possibly Liocarpilodes sp., found on the undersides of settlement tiles. Studying the tiles under a microscope, researchers sometimes find one bright, shiny compound eye looking back at them from a small hole in the surface where the crabs take refuge.  [Less] [Link to this slide]

An egg cowrie snail (Ovula ovum), its velvety black mantle contrasting with its glossy white shell, consumes a leather coral (Sarcophyton sp.) on a back reef at Palmyra Atoll.

COCONUT CRAB

The coconut crab ( Birgus latro ) is the largest land invertebrate in the world. Originally distributed on islands throughout the Indo-Pacific region, the mostly nocturnal crab has been overexploited for food and extirpated on most islands inhabited by people....[More]

COCONUT CRAB

The coconut crab (Birgus latro) is the largest land invertebrate in the world. Originally distributed on islands throughout the Indo-Pacific region, the mostly nocturnal crab has been overexploited for food and extirpated on most islands inhabited by people. Like other members of its terrestrial hermit crab family, when it is younger and smaller, the coconut crab has an asymmetrically twisted body adapted to use coiled snail shells. Eventually it outgrows available shells and molts to become a nontwisted, free-living crab.  [Less] [Link to this slide]

FISH EGGS

Several groups of small reef fish, such as gobies (Gobiidae), damselfish (Pomacentridae), and dottybacks (Pseudochromidae), include species that lay clutches of eggs in protected crevices....[More]

FISH EGGS

Several groups of small reef fish, such as gobies (Gobiidae), damselfish (Pomacentridae), and dottybacks (Pseudochromidae), include species that lay clutches of eggs in protected crevices. An unidentified fish laid its eggs, which have developed into embryos about 0.02 inch (0.55 millimeter) in diameter, on the underside of a settlement tile. Using the energy stored in golden drops of oil, these embryos grow well-developed eyes and elongated bodies that stay tightly wrapped within their capsules until hatching.  [Less] [Link to this slide]