Paul Ollig's Science in the Crown Blog

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Rock Snot in Glacier

Didymo, a type of algae that can grow profusely on rocks in cold streams, rivers and lakes in Glacier National Park, is commonly referred to as "rock snot".

Loren Bahls

Rock Snot: The Crown's Hidden Jewels
December 7, 2009

Current Weather Conditions at Glacier National Park Headquarters
Temp: -8°F
Sky: Partly Cloudy
Wind: Calm

Anyone who has ever tried crossing one of Glacier National Park's many cold, rocky streams in late summer has undoubtedly encountered the slippery, fuzzy algae covering the rocks. Commonly referred to as "rock snot," many people tend to curse the decidedly unappealing organism as they slip and fall their way over the rocks. But a closer examination of what looks like an ugly blob of goo reveals a world of exquisite and hidden beauty.

Dr. Loren Bahls, curator of the Montana Diatom Collection and faculty affiliate at the University of Montana, is a local expert on diatoms, a variety of algae that is one of the most common types of phytoplankton on the planet. What we see as rock snot is simply a huge colony of these single-celled plants, it's greenish color derived from the chlorophyll inside each one.

Loren spent the summer of 2009 gathering samples of rock snot from throughout Glacier National Park to determine the diversity of this often overlooked part of the ecosystem. What he discovered is extraordinary.

Didymosphenia geminata

A microscope reveals the exquisite beauty behind the slippery goo known as "rock snot". This beautiful specimen, Didymosphenia geminata, is one of the most common species of diatoms found in Glacier National Park.

Loren Bahls

Rock Snot under the microscope

Exploring the incredible diversity found in tiny samples of rock snot is like digging for buried treasure for Dr. Loren Bahls. Each individual he finds is like discovering a tiny jewel, with each species having its own unique shape (left: Placoneis abiskoensis; right: Neidium ampliatum).

Loren Bahls

For Loren, sifting through samples of "snot" with the help of a powerful microscope is like searching for buried treasure. Tiny, three-dimensional jewels float past his eyes as he sorts through them. He combs through each sample identifying as many species as possible, mostly by their shape and color. Each one unique and exquisitely beautiful.

Counting diatoms is is a very tedious process. Analyzing a sample that would barely fill a teaspoon can take days of peering into the microscope. But the payoff is incredible. In a single tiny sample he collected from Logging Lake, on the west side of Glacier National Park, he found 163 different species! Included were several new records for the park, two new records for the Pacific Northwest and three unknowns!

But these beauties have a dark side. Didymo, short for Didymosphenia geminata, the most common species of diatom in Glacier, can sometimes form large algal blooms under the right conditions. These outbreaks of rock snot can inhibit the growth of other organism, such as aquatic insects, and can negatively impact the health of the park's aquatic ecosytems.

Loren's work studying diatoms, and identifying which species currently inhabit the park's waters, will help park managers better understand the impact of "rock snot" blooms on the park's ecosystems. Will the park's changing climate affect the growth of didymo and other diatoms? What effects will these changes have on the park's endangered bull and westslope cutthroat trout populations? These are the next questions we need to answer.

In the meantime, the next time you find yourself slipping and sliding your way over river rocks covered with "snot", take a moment to appreciate the unseen beauty of this curious little plant, the hidden jewels in the Crown of the Continent.


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