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Alaska ‘Orange Goo’ Rust Spores Confirmed

Published on: 02/09/2012
Region(s) of Study: Foreign Countries

An ‘orange goo’ covered the shoreline of thethe Inupiat village of Kivalina, Alaska last summer. It alarmed residents, perplexed local state and federal agencies and caused an international sensation via the press. Residents thought it was a harmful algal bloom similar to Noctiluca which is common to nearshore Alaska waters. Samples were sent NOAA’s Analytical Response Teamwhoidentified the orange substance asspores of a rust fungus, but not being experts of terrestrial plants did not make a species identification.

Six months later the substance was identifiedby forest health professionalsat the USDA Forest Service and the Canadian Forest Service to bespores of the rust fungusChrysomyxa ledicola. This fungus is a plant pathogen that infects the foliage of spruce (Piceaspp.) and Labrador tea (Ledumspp.).

Many rust fungi have complex lifecycles, with five spore stagescompleted on two very different types of host plants. It is thoughtthat the spore stage detected near Kivalina is the aeciospore stage,which is produced on current-year spruce foliage in late summer andspreads through the air to infect Labrador tea. Large scale outbreaksof spruce needle rust are not unprecedented in Alaska, and the largequantities of spores have been known to discolor river water.

The rapid response by NCCOS scientists and outreach specialists to correctly identify the mysterious orange goo quickly resolved health concerns of local residents and provided correct information to the Alaska Fisheries.Spore identification was based on the physical features of the spores (shape, size and appendages) at high magnification using scanning electron microscopy. Genetic sequencing can also be used for identification, but the spores were too degraded for sequencing after storage in seawater.

NCCOS researchers will support USDA’s summer 2012 collection effort by providing scanning electron microscopy identification of the spores to track the extent of this fungus in western Alaska.

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