A microbialite powered food chain

Great Salt Lake owes its fecundity to the unusual collection of microbialites on its lakebed. Microbialites are akin to a reef, grown over centuries by the metabolic activities of the lake’s salt-loving microbes. These structures are veritable bird food factories. Through photosynthesis, they generate a tremendous amount of biomass that feeds the lake’s only two invertebrates - brine flies and brine shrimp - which reach very high density in the lake and feed millions of migratory birds.

This collection takes a closer look at the ancient “living rocks” of the lakebed and their role in the Great Salt Lake ecosystem.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

The mounded forms of Great Salt Lake's ancient microbialites are revealed as the Great Salt Lake dries up.

The mounded forms of Great Salt Lake's ancient microbialites are revealed as the Great Salt Lake dries up.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

A pool of water trapped in the contours of the microbialite reef. As the pools dry, salinity increases, favoring a population of extreme halophilic microbes that are pink to orange in color.

A pool of water trapped in the contours of the microbialite reef. As the pools dry, salinity increases, favoring a population of extreme halophilic microbes that are pink to orange in color.

A pool of water from the receding Great Salt Lake is trapped in the contours of the microbialite reef. As the pools dry, salinity increases, favoring a population of extreme halophilic microbes that are pink to orange in color.

A pool of water from the receding Great Salt Lake is trapped in the contours of the microbialite reef. As the pools dry, salinity increases, favoring a population of extreme halophilic microbes that are pink to orange in color.

A partially submerged microbialite showing salt crystalizing above, and brine fly larvae and brine shrimp attached below the waterline. The black material is a mat of photosynthetic microbes that the brine fly larvae and brine shrimp feed on.

A partially submerged microbialite showing salt crystalizing above, and brine fly larvae and brine shrimp attached below the waterline. The black material is a mat of photosynthetic microbes that the brine fly larvae and brine shrimp feed on.

Submerged microbialite "bird food factory" showing brine fly larvae and brine shrimp attached. The black material is the mat of photosynthetic microbes that the invertebrates feed on.

Submerged microbialite "bird food factory" showing brine fly larvae and brine shrimp attached. The black material is the mat of photosynthetic microbes that the invertebrates feed on.

Adult brine flies massing on the Great Salt Lake shoreline. Brine flies spend much of their lives underwater in larval form, attached to microbialites, where they are eaten year-round by diving ducks and grebes. After hatching, they float to the su

Adult brine flies massing on the Great Salt Lake shoreline. Brine flies spend much of their lives underwater in larval form, attached to microbialites, where they are eaten year-round by diving ducks and grebes. After hatching, they float to the surface in large rafts where they feed millions of shorebirds and gulls.

An American Avocet plucks at insects on the bleached microbialite reef at Great Salt Lake. The lake has lost over eleven feet of elevation, exposing many miles of its microbialite reef to desiccation and bleaching.

An American Avocet plucks at insects on the bleached microbialite reef at Great Salt Lake. The lake has lost over eleven feet of elevation, exposing many miles of its microbialite reef to desiccation and bleaching.

An American Avocet guards a nest near a puddle trapped in the contours of the exposed microbialites of Great Salt Lake.

An American Avocet guards a nest near a puddle trapped in the contours of the exposed microbialites of Great Salt Lake.

California gulls feed by running along the shore of the Great Salt Lake, raising up clouds of brine flies and snapping them up. Brine flies are one of only two invertebrates that thrive in the salty waters of the Great Salt Lake, reaching enormous p

California gulls feed by running along the shore of the Great Salt Lake, raising up clouds of brine flies and snapping them up. Brine flies are one of only two invertebrates that thrive in the salty waters of the Great Salt Lake, reaching enormous population densities and providing food for millions of shorebirds, waterfowl, and gulls.

Great Salt Lake hosts the world's largest concentration of threatened Western Snowy Plovers. The birds nest on the beaches and playas of the lake, feeding on plentiful insects. Here a Western Snowy Plover stands among exposed microbialite mounds.

Great Salt Lake hosts the world's largest concentration of threatened Western Snowy Plovers. The birds nest on the beaches and playas of the lake, feeding on plentiful insects. Here a Western Snowy Plover stands among exposed microbialite mounds.

A Wilson's Phalarope plucks brine flies from the surface of Great Salt Lake during a smoky sunset. Great Salt Lake and its brine fly buffet attracts the largest staging concentration of Wilson's Phalaropes in the world, with as many as 500,000 birds

A Wilson's Phalarope plucks brine flies from the surface of Great Salt Lake during a smoky sunset. Great Salt Lake and its brine fly buffet attracts the largest staging concentration of Wilson's Phalaropes in the world, with as many as 500,000 birds visiting at peak migration.

A young California gull feeds by running along the shore of the Great Salt Lake, raising up clouds of brine flies and snapping them up.

A young California gull feeds by running along the shore of the Great Salt Lake, raising up clouds of brine flies and snapping them up.

A Franklin's gull feeds by running along the shore of the Great Salt Lake, raising up clouds of brine flies and snapping them up.

A Franklin's gull feeds by running along the shore of the Great Salt Lake, raising up clouds of brine flies and snapping them up.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

Pools of water from the receding Great Salt Lake are trapped in the contours of the microbialite reef.

Pools of water from the receding Great Salt Lake are trapped in the contours of the microbialite reef.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

Partially submerged microbialites showing the desiccated and bleached part above, and the dark microbial mat at the waterline where the structures are still hydrated.

Aerial view of Antelope Island in Great Salt Lake showing large areas of exposed and bleached microbialites. Submerged microbialites can be seen in the water in the foreground. Submerged microbialites are threatened by increasing salinity as the lake

Aerial view of Antelope Island in Great Salt Lake showing large areas of exposed and bleached microbialites. Submerged microbialites can be seen in the water in the foreground. Submerged microbialites are threatened by increasing salinity as the lake dries up.

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