The scleractinian coral genus Acropora is a competitively dominant species in shallow coral reefs of the Indo-Pacific. It is highly susceptible to bleaching, which is thought to be primarily caused...

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A sockeye salmon (Oncorhynchus nerka) in a small breeding stream in southwestern Alaska. Adult sockeye lay their eggs in the gravel of streams, rivers, or along the beaches of lakes in late summer...

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The southern torrent salamander (Rhyacotriton variegatus) inhabits small, cool, headwater streams and seeps in conifer-dominated forests, primarily in the Coast Ranges of Oregon and northern...

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A tributary to the Turure River enters the main stream. The tributary (in the center of the photo) runs below the road cut. The main part of the stream (along the bottom of the photo) comes from an...

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A variegated meadowhawk dragonfly (Sympetrum corruptum) perches in a California rice field. Rice fields are widespread agricultural ecosystems that provide habitat for many wetland species, such as...

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A Volvox colony from a freshwater lake in British Columbia, Canada. Volvox is a genus of green algae that forms colonies of numerous cells. A recent survey of lakes in British Columbia found that...

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The Bow Valley in Banff National Park, Canada, was recolonized by wolves (Canis lupus) in the mid-1980s, although wolves did not establish themselves in areas near the growing town of Banff. This...

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abandoned mine drainage, Pennsylvania, anthracite mining

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Fire is a natural factor that maintains the pinelands and other natural communities in South Florida. The frequency of these fires is influenced by large-scale climate cycles, particularly El Nino...

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An aerial view of Lake Christina, MN, during turbid-state (ca. early 1980s). Pelican Lake (immediately downstream) is visible on lower right. The effects of turbid water discharging from Lake...

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