- Angela De Palma-Dow
- Posted On
Lady of the Lake: Look, look! It’s Langmuir lines!
Dear Lady of the Lake,
Many of our members of our sailing club sometimes see langmuir lines out in Clear Lake. We'd love to hear what you might have to say about them.
Thanks!
— Come Sail with Us at Konocti Bay Sailing Club
Dear Konocti Bay Sailing Club,
Thanks for that question! This is one of my favorite types of questions because as a limnologist I get to share some awesome nerd facts for lake fans! In case you were wondering, a linologist is one who studies limnology, which is the study of fresh inland waters, including the biological, chemical, and physical processes within any fresh waters such as lakes, ponds, wetlands, streams, and creeks. Langmuir lines are physical processes, or phenomena, that occur on large lakes.
Firstly, Langmuir lines or Langmuir circulations (sometimes called “scum, foam, or algae lines”) are surface “lines” that are observed on large lakes and oceans, made up of lines or streaks of foam, sometimes called windrows (pronounced Wind-Rows), that form along the parallel edges of vertical rotating cells. During certain wind conditions, Langmuir lines can exist across large expanses of surfaces on open water, sometimes reaching for miles in very large lakes.
If the above description seemed technical and confusing, don’t worry, I will break down the specific mechanisms that form Langmuir lines in a few paragraphs.
The question about Langmuir lines also has a fascinating answer that involves a description of a physical process that inserts geometry, math, and patterns into nature. Many times we see patterns or shapes in natural systems and it’s always unexpected and amazing to see nature working with straight lines, symmetry, and numerical patterns. Langmuir lines are a prime example of nature being expressed in amazing ways.
OK, first let’s discuss how these striations got the name “Langmuir lines.”
Dr. Irving Langmuir: A physical chemist, limnologist, and science-fiction cultural inspiration
Like most naturally observed phenomena in science and engineering, discoveries made prior to the 1970/1980’s were mostly named after the lead scientist or scientists that “discovered” and described the phenomena in a published record, even if the phenomena had a description prior to that “discovery”. This is called Stigler's law of eponymy.
Many times, physical or mathematical phenomena had pre-existing traditional descriptions, sometimes existing for hundreds or thousands of years before they were “discovered” and given a “new” name. The names and titles we most commonly associate with these observances today were provided by the wave of scientific discovery that came out of the industrialization of the modern western civilizations.
Dr. Irving Langmuir was a physical chemist that did happen to uniquely discover and invent many scientific milestones, due to the advancements in technologies that industrialization made possible. In the case of Langmuir Lines, my research has not revealed any previous descriptions that existed, but of course this is limited to the written or digital record, and I fully recognize and acknowledge that there could be a description and name out there that predates Langmuirs’.
Dr. Irving Lanmuir made an observation of Langmuir Lines during a cross-atlantic journey to England in 1927. He was so intrigued, that when he returned to the States, he spent several years studying Lake George in upstate New York to further understand the mechanics behind what would later be called Langmuir Circulations, or Langmuir Lines.
Dr. Langmuir, a Columbia University engineering graduate, completed his doctorate at University of Göttingen, in Germany. After leaving academia, he worked with General Electric for about 40 years and invented the gas-filled incandescent lamp in 1913. In 1928 he coined the term “plasma” in reference to ionized gasses based on his study of charged particles emitted from filaments. His filament work led to many advances in light bulb technology that made lightbulbs in the first half of the 1900’s more efficient, more affordable, and longer-lasting.
Dr. Langmuir was awarded the Nobel Prize in Chemistry in 1932 and his contributions to surface chemistry were so significant that the American Chemical Society named its Journal of Surface Chemistry and Colloids, Langmuir, after Dr. Irving Langmuir himself.
Kurt Vonnegut’s science fiction novel Cat’s Cradle, published a few years after Langmuir’s death, paid homage to the scientist. Apparently, the main physicist in the novel is a nobel laureate whose life shares parallels to that of Langmuir. We will never know if Irving appreciated the comparison, especially in the context of the novel’s theme, but for the world, Lagmuir’s reach and influence was significant and broad and that is the best any scientist can hope and wish for.
Deep water + Wind = Surface Water Movement or Langmuir Circulation
To understand the movement of surface water that forms Langmuir Lines, you should first be aware that lakes and oceans have layers throughout the water column. Think of a sandwich with a top, middle, and bottom layer - but each layer has its own characteristics based on light, temperature, and movement.
The top layer, called the Epilimnion, is the surface layer and the water here is the warmest (when there is no ice cover) and most active with movement, from wind and surface currents. The layer at the very bottom of a lake or ocean, is very quiet, still, dark, and cold, and called the Hypolimnion.
The layer between the top and bottom layer is called the Metalimnion, and this layer is usually the largest layer, and shares some qualities of both layers. Usually the metalimnion is warmer than the hypolimnion, but colder than the epilimnion. One thing about the metalimnion is that it’s usually really stable and does not contain much movement unless it’s being acted upon by the top or bottom layer. For example the metalminon might mix thoroughly with both layers during seasonal change, when the surface layer gets really cold and dense and sinks to the bottom.
When the lake layers are not mixing, and in their stable states, this is called lake stratification. Langmuir lines do not occur when mixing is occurring and only occur when the lake is stratified. That is because the water movement that occurs in the epilimnion is isolated, think of the atmosphere and the metalimnion being a top and bottom to the surface zone, epilimnion, of the lake or ocean.
High winds blowing in one consistent direction can cause Langmuir lines, but the wind has to be strong (greater than 11 mph or 10 knots) but not so strong that large surface waves form, which can obscure or disrupt the Langmuir line formations. The water current, if there is one, also has to be going in the same direction as the wind as cross currents will prohibit the rotations. Langmuir lines are more commonly observed in deep water bodies, although more studies being conducted in tropical lake systems are observing Langmuir circulations under certain conditions in shallow water bodies.
The wind moves the water sideways to the wind, either left or right, but in alternating directions, creating upwellings and downwellings in an alternating pattern. Think of corkscrews lined up next to each other but going in opposite directions. These are called vertical rotating cells, sandwiched between the surface of the water and the bottom of the epilimnion. The cells do not extend into the metalminon, in fact the middle layer of water acts like a hard surface, binding downward extrent of the vertical rotating cells.
So think of these rows of alternating spirals of water going in opposite directions; and we can easily see how foam, plants, trash, or other debris can get pushed into the parallel lines formed between the cells at the surface of the water. The collection of materials, between the cells, creates the appearance of straight, parallel, streaks on the surface of the water, and hence Langmuir lines.
Since Langmuir’s observation and description of his self-titled circulations, many physicists and limnologists have studied langmuir lines in great detail, and have been able to further explain their occurrence, shapes, flows, and the specific conditions that drive them to form and disappear. Most of these investigations have been possible through what are called “tracer studies”, where traceable or tagged particles are dropped in the water during an occurring Langmuir circulation and the movements can be further understood and described.
More visual details and information about the additional contribution to langmuir lines are summarized in this great video on the SciencePrimer youtube channel called “What are those streaks on the water? - Langmuir Circulation."
Again, thanks for the question Konocti Bay Sailing Club, and I will leave you with a wonderful quote by Dr. Dori Lal from her 2015 paper in the publication called The Signage. Langmuir lines are a perfect example of the “beauty of nature as revealed by geometry and the beauty of geometry as revealed in nature”.
Sincerely,
Lady of the Lake
Angela De Palma-Dow is a limnologist (limnology = study of fresh inland waters) who lives and works in Lake County. Born in Northern California, she has a Master of Science from Michigan State University. She is a Certified Lake Manager from the North American Lake Management Society, or NALMS, and she is the current president/chair of the California chapter of the Society for Freshwater Science. She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it.. You can now hear from the Lady on the Lake on local radio, KPFZ 88.1, the last Sunday of every month, during the “Lake County Fire Recovery” and “What’s Next” weekly shows between 2 and 4 p.m.