Foam on the water a sign of life, death

While sitting in the front of a canoe on a twisty Alaska creek, my daughter asked to steer closer to the riverbank. She wanted to grab some suds. There, caught in the elbows of fallen trees, were quivering mounds of white foam.

Foam is floating on most Alaska waterways this summer. Years ago, when I first saw yellowish suds on a creek that ran behind my cabin, I thought something manmade and nasty spilled upstream. But the Pearl Creek foam and other globs seen far from towns are probably natural.

David Wartinbee of Soldotna knows this because he has sought out river scum for scientific purposes. The aquatic ecologist, attorney and pilot has for years gathered foam from streams and lakes. Within it, he finds the shed pupal skins of delicate midges that began their lives in the waterway. Using foam as his collecting agent, Wartinbee identified 88 species of midges that live in the Kenai River.

So where does the foam come from? It emerges from anything that was once alive that sheds fatty molecules during decomposition.

Plants are a major foaming agent. Dead parts of plants, like birch leaves that fell the preceding fall, contain lots of lipid molecules. Lipids are fats and oils that make up things like waterproof plant cell walls. Lipid molecules don’t mix with water. They float on the water like an invisible layer of liquid dish soap.

Waves beat the fatty skim to a froth. Air gets beneath the film. Bubbles form and multiply, piling against logs and rocks. The resulting foam can last for a long time, until bacteria gobbles it up.

Foam often turns yellow or brown as its blob captures other floating debris, like the former skins of waterborne flies, pollen, seeds, algae and moss spores. Foam is a good recorder of what’s going on in a stream.

Plants growing and dying in Alaska’s bogs and wetlands deliver loads of carbon to streams, often staining them the color of iced tea. These streams, like the river my daughter and I were on, tend to be foamy ones during times when rain or snowmelt rinses the land.

Foamy water can also be the result of pollution, but that probably doesn’t happen much in Alaska, especially far from cites and villages. Soaps and detergents don’t drift far from the source and will often reveal the scent of perfume added to the soap.

“In some places, like when the Cuyahoga River in Ohio was catching on fire, foam told you things are bad,” Wartinbee said. “But it’s a perfectly normal part of stream activities.”

Since the late 1970s, the University of Alaska Fairbanks’ Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.

More in Life

This Korean rice porridge, called dak juk, is easy to digest but hearty and nutritious, perfect for when you’re learning how to eat. (Photo by Tressa Dale/Peninsula Clarion)
A comforting meal for new beginnings

Rice porridge is a common first solid meal for many, many babies around the world

file
Minister’s Message: The sound of God’s voice

In all my desperate prayers, I sometimes forget that God has spoken definitively already

Rivers and Ice by Susan Pope. (Promotional photo)
KPC Showcase to feature discussion with Alaska author Susan Pope

Pope will discuss her memoir “Rivers and Ice: A Woman’s Journey Toward Family and Forgiveness”

Promotional photo courtesy Sony Pictures
Carrie Coon, Paul Rudd, Finn Wolfhard, Mckenna Grace and Celeste O’Connor appear in “Ghostbusters: Frozen Empire.”
On the Screen: New ‘Ghostbusters’ struggles to balance original ideas and nostalgia

“Ghostbusters: Frozen Empire” picks up right where “Afterlife” left off, and it also succumbs to a lot of the same problems

document from ancestry.com
William Raymond “W.R.” Benson’s draft-registration card from 1942 reveals that he was 52 years old, living in Seward and self-employed. His wife, Mable, is listed as a person who will always know his address.
Hometown Booster: The W.R. Benson Story — Part 2

W.R. Benson was a mover and a shaker throughout his life, but particularly so in Alaska

Terri Zopf-Schoessler and Donna Shirnberg rehearse “The Odd Couple: The Female Version” at the Kenai Performers’ Theater near Soldotna, Alaska, on Tuesday, March 19, 2024. (Jake Dye/Peninsula Clarion)
‘Iconic, classic comedy’

Kenai Performers debuts “The Odd Couple: The Female Version”

Photo provided by Sara Hondel
Sara Hondel stands with a leprechaun during Sweeney’s St. Patrick’s Day Parade in Soldotna on Sunday. Green, leprechauns and Nugget the Moose poured down the streets for the 34th annual parade hosted by the Soldotna Chamber of Commerce. Under cloudy skies — but fortunately no precipitation — a procession of viridescent celebrants representing businesses and organizations brought festivities to an array of attendees lining Redoubt Avenue.
Go green or go home

Soldotna turns out for St. Patrick’s Day parade

Eggplants, garlic, lemon juice and tahini make up this recipe for baba ghanouj. (Photo by Tressa Dale/Peninsula Clarion)
When making a good example is hard to swallow

Preparing baba ghanouj despite a dislike of eggplant

William Raymond “W.R.” Benson (front row, far right) poses along with the rest of the Sigma Nu fraternity at Albion College in Michigan in about 1908. Despite a lifetime spent in the public eye, Benson was apparently seldom captured on film. This image is one of the few photos of him known to exist. (photo from the 1908 Albion College yearbook via ancestry.com)
Hometown Booster: The W.R. Benson Story — Part 1

W.R. Benson was a man almost constantly in motion

Most Read