The science behind the magic: Fall color explained

yellow-glory-by-scottie

Untitled, photo by Scottie

The Science of Color in Autumn Leaves from the United States National Arboretum is such an excellent explanation of the science behind the magic of Michigan’s fall color show that I try and share it every year:

The process that starts the cascade of events that result in fall color is actually a growth process. In late summer or early autumn, the days begin to get shorter, and nights are longer. Like most plants, deciduous trees and shrubs are rather sensitive to length of the dark period each day. When nights reach a threshold value and are long enough, the cells near the juncture of the leaf and the stem divide rapidly, but they do not expand. This abscission layer is a corky layer of cells that slowly begins to block transport of materials such as carbohydrates from the leaf to the branch. It also blocks the flow of minerals from the roots into the leaves. Because the starting time of the whole process is dependent on night length, fall colors appear at about the same time each year in a given location, whether temperatures are cooler or warmer than normal.

During the growing season, chlorophyll is replaced constantly in the leaves. Chlorophyll breaks down with exposure to light in the same way that colored paper fades in sunlight. The leaves must manufacture new chlorophyll to replace chlorophyll that is lost in this way. In autumn, when the connection between the leaf and the rest of the plant begins to be blocked off, the production of chlorophyll slows and then stops. In a relatively short time period, the chlorophyll disappears completely.

This is when autumn colors are revealed. Chlorophyll normally masks the yellow pigments known as xanthophylls and the orange pigments called carotenoids — both then become visible when the green chlorophyll is gone. These colors are present in the leaf throughout the growing season. Red and purple pigments come from anthocyanins. In the fall anthocyanins are manufactured from the sugars that are trapped in the leaf. In most plants anthocyanins are typically not present during the growing season.

As autumn progresses, the cells in the abscission layer become more dry and corky. The connections between cells become weakened, and the leaves break off with time. Many trees and shrubs lose their leaves when they are still very colorful. Some plants retain a great deal of their foliage through much of the winter, but the leaves do not retain their color for long. Like chlorophyll, the other pigments eventually break down in light or when they are frozen. The only pigments that remain are tannins, which are brown.

The explain that because the starting time of the whole process is dependent on night length, fall colors appear at more or less the same time every year and are not overly dependent on temperature, rainfall or other factors, other than the fact that weather can shorten or prolong the show by stripping leaves from trees.

Click through to the US Arboretum for more and also see Fall & Fuit from the Science of Color!

View Scotties’ photo bigger and see more in his Infrared slideshow.

Tons more fall photos on Michigan in Pictures!

Bringing the Busy Bee back to Michigan

the-busy-couple-of-bees

The busy couple, photo by Jiafan (John) Xu

John writes that this photo was taken at a small pond with pink lotus and some other water plants at the Michigan State University farm in Novi, Michigan. That segues nicely to this Greening of the Great Lakes interview with Dr. Rufus Isaacs, bee researcher and professor in the Department of Entomology at MSU about what we can do to make our farms and gardens better for bees.

He (Dr. Isaacs) believes the use of pesticides, disease and reduced natural habitat from the development of land for residential and agricultural purposes have made it difficult for the over 400 different bee species native to Michigan to survive and pollinate.

Among other things, Isaacs and his colleagues hope to expand spaces for wild bees to thrive close to farmland. His strategy to improve pollination sustainability involves luring wild bees to farms so producers don’t have to rent commercial honey bees. By planting wildflowers and using bee-safe pesticides, farmers can become less dependent on high-cost and out-of-state honey bees to pollinate their crops.

“We’re supporting those bees with pollen, nectar and a place to nest, “ he says. “That’s boosting those wild bee numbers to help honey bees when it’s bloom time in the Spring.”

Similar procedures can also be done on a smaller scale to increase pollination and mitigate bee decline. Isaacs explains that home gardeners can look to resources like MSU’s Smart Gardening program to attract pollinators to their fruit and vegetable plantings.

Click through to listen!

View Jiafan’s photo bigger and see more in his slideshow.

Northern Lights and a Proton Arc!

Milky Way, A Proton Arc, and the Northern Lights

The Milky Way, A Proton Arc, and the Northern Lights!, photo by Eric Hackney

Last night I got a couple of texts that the northern lights were out. By the time I got to the beach here in northern lower Michigan, they had died back to a soft arc on the horizon. Up on the Keweenaw however, they were pretty spectacular!

In addition to being spectacular, Eric’s photos introduced me to a new northern lights term, the mysterious proton arc or proton aurora. which NASA’s Astronomy Picture of the Day explains in this link filled post (picture is below):

What are auroras made out of? Triggered by solar activity, normal auroras are caused by collisions between fast-moving electrons and the oxygen and nitrogen in Earth’s upper atmosphere. The electrons come from the magnetosphere, the region of space controlled by Earth’s magnetic field. As the excited oxygen and nitrogen molecules return to their low energy state, they emit light, seen as the auroral glow.

Sometimes, however, auroras can be caused by collisions with heavier protons, causing a more energetic display with strong ultraviolet emission. In addition, protons can temporarily capture an electron and emit light for themselves. Such a proton aurora is seen above, recorded by the IMAGE satellite. A special feature is the bright spot near picture center, embedded in a ring of auroral emission around the north magnetic pole of planet Earth.

Most solar wind protons never reach the Earth to cause auroras because they are completely deflected away at a great distance by the Earth’s magnetic field. The bright spot in the auroral ring indicates a particularly deep crack in the Earth’s magnetic field where protons were able to flow along a temporarily connected region between the Sun and the Earth, relatively undeflected, until they impacted the Earth’s ionosphere.

Read on for lots more. The good news? It looks like the wide coronal hole that was responsible for last night’s aurora will continue to kick out the celestial jams for a couple of days, meaning this weekend offers a great chance to see the northern lights in Michigan!

View Eric’s photo bigger and see more in his 9-1-16: Northern Lights IX slideshow.

Much more about the northern lights / aurora borealis on Michigan in Pictures!

Photo courtesy NASA:

Proton Arc Nasa

Only Getting Hotter

Eye in the Sky by Noah Sorensen

Eye in the Sky, photo by Noah Sorensen

“The heat is rising and only getting hotter, ready to blow
I think I’ll pour myself a glass of water, let it flow
She’ll show you what she’s made of
Yeah she’s comin’ for ya
She’s gonna try to break ya
Yeah she’s comin’ for ya
No, she don’t mess around”
-Cage The Elephant, Mess Around

You know that when I pull out Cage the Elephant lyrics, I’m probably going to say something that will anger a slice of Michigan in Pictures readers, so be warned! Longtime readers will also know that I am pretty committed to saying what I want to say, so it’s probably good keep that in mind as well.

Speaking of warnings, the National Aeronautics and Space Administration (NASA) spends a lot of time looking at the Earth and crunching data from an extensive satellite and – in conjunction with the National Oceanic and Atmospheric Administration (NOAA). Anyway, these folks – literally rocket scientists – have reported (based on science and data) that the Earth is warming at an unprecedented rate:

The planet is warming at a pace not experienced within the past 1,000 years, at least, making it “very unlikely” that the world will stay within a crucial temperature limit agreed by nations just last year, according to Nasa’s top climate scientist.

This year has already seen scorching heat around the world, with the average global temperature peaking at 1.38C above levels experienced in the 19th century, perilously close to the 1.5C limit agreed in the landmark Paris climate accord. July was the warmest month since modern record keeping began in 1880, with each month since October 2015 setting a new high mark for heat.

But Nasa said that records of temperature that go back far further, taken via analysis of ice cores and sediments, suggest that the warming of recent decades is out of step with any period over the past millennium.

“In the last 30 years we’ve really moved into exceptional territory,” Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies, said. “It’s unprecedented in 1,000 years. There’s no period that has the trend seen in the 20th century in terms of the inclination (of temperatures).”

Read on for more. I’d like to go on record as a parent and member of the human race that I’m really alarmed by this, and also the fact that what appears to be a serious emergency is being ignored.

View Noah’s photo background bigtacular and see more in his slideshow.

I would really like to share the video of Mess Around from Cage the Elephant because I really like the band. In the interests of responsibility however, here’s a 30-second video showing the temperature rise of the last 145 years:

Glory Lake Sunrise and Kettle Lakes

Glory Lake Sunrise

wGlory sunrise 1, photo by Jeff Caverly

The Michigan DNR’s page on Bright and Glory Lakes near Grayling includes maps. They say that both lakes have floating piers & boat launches for fishing – species include largemouth bass, rainbow trout, smallmouth bass, sucker, sunfish, yellow perch:

These lakes are called Kettle Lakes as they are shaped like tea kettles. They are roundish and deep in the center (more than 40 feet). The lake bottom is marl, so wading and swimming are prohibited as people would sink in the marl.

Here’s more about Kettle Lakes from MSU’s Geology department:

Kettles are depressions left behind after partially-buried ice blocks melt. Many are filled with water, and are then called “kettle lakes”. Most lakes in Michigan could be described as kettle lakes, and the term “kettle lake” describes the way the lake basin was formed. Kettle lake basins were formed as the glaciers receded. While this was happening, a block of ice broke off the glacier, and just sat there. As the glacier continued to melt, the debris from the glacier (soil, rocks, stones, gravel, etc.) filled in around the block of ice. When the block of ice finally melted, all the debris surrounding it fell into the hole, creating the kettle type basin, which when filled with water, became a lake as we know it.

Many of our small, deep lakes in Michigan are kettle lakes. Some have since been infilled with vegetation and plant matter, to form bogs. Even some of our larger, deep lakes, like Higgins Lake and Walled Lake, are kettles.

View Jeff’s photo background big, see more including another view of the sunrise in his slideshow, and follow Jeff Caverly Photography on Facebook.

Agate Beach in Grand Marais … and Lake Superior Agates

Agate Beach Treasures Neil Weaver Photography

Agate Beach Treasures, photo by Neil Weaver Photography

Karen “Agatelady” Bryzs of the Gitchee Gumee Museum in Grand Marais shares a ton of information about Lake Superior Agates, part of a worldwide family of semi-precious gemstones that naturally develop when an empty pocket inside a host rock fills in with microcrystals, forming a totally unique pattern:

Most Lake Superior agates formed in a rift zone approximately 1.2 billion years ago. Rift zones are cracks in the Earth’s surface out of which molten lava flowed. Today, there are still rift zones at the bottom of the Pacific and Atlantic oceans. The rift zone that created Lake Superior agates started in what is now northeast Kansas and continued northeast into what is now the western end of Lake Superior. This hot spot domed up lava several miles high and eventually choked itself off. If it would have continued, it could have split the North American continent in half.

She offers some tips from her book “Understanding and Finding Agates“:

  • Scan the beach and look for the Iron oxide red color.
  • Look for rocks that show evident concentric banding.
  • Check for possible entrance and/or escape channels that allowed gases or originally escape from the cavity, silica-rich water to enter, and pressure formed during the agate precipitation process to escape.
  • Search for rocks with conchoidal fractures that give the specimen a more angular, irregular shape.
  • When the angle of sun is low on the horizon, walk toward the sun and look a distance in front of you to look for the extremely translucent red carnelian agates.

Read on for lots more and definitely stop in the Gitchee Gumee Museum if you make it to Grand Marais! (done it, loved it!)

View Neil’s photo of agates near Grand Marais bigger, see more in his slideshow, and view and purchase his photos at neilweaverphotography.com.

Summer Solstice and a Strawberry Moon

Summer Solstice 2013 by Ken Scott

Summer Solstice … 2013, photo by Ken Scott

Today at 6:34 PM EDT, the summer solstice officially ushers in summer. EarthSky shares that the full Strawberry moon tonight for the solstice is the first full moon to fall on the summer solstice since June of 1967 and the Summer of Love.

Back in 2001, NASA’s Earth Science Picture of the Day (<–my favorite photo blog – subscribe!) shared the tale of Eratosthenes, the Solstice and the Size of the Earth:

Calculating the SolsticeIt was near the summer solstice of 240 BC that Eratosthenes, curator of the famed Library of Alexandria and renowned mathematician and geographer, performed his famous experiment in Egypt to calculate the diameter of the Earth. The bottom of a deep well in the city of Syene, Egypt (near the present day Aswan Dam and very near the Tropic of Cancer) was known to be illuminated by the sun directly at mid-day on the longest day of the year (the solstice). But on the same day, a vertical pole in Alexandria, some 800 km to the north, cast a distinct shadow. By measuring the shadow and applying the geometry of a sphere, Eratosthenes calculated the Earth’s diameter with remarkable accuracy. Sadly, the concept of a spherical Earth was lost from common thought for over a thousand years until Christopher Columbus and others proved the fact by sailing west to go east. The background reference image of Egypt and the Nile River is provided by the NASA MODIS instrument.

Sep 5, 2006 – Donald Etz notes: “From reading Jeffrey Burton Russell’s book, Inventing the Flat Earth (1991), I was persuaded that most educated Europeans of Columbus’ time believed the earth is round. The main debate seems to have been over its dimensions. Columbus ventured on his voyage because he believed the earth was much smaller than it is.” -ed

View Ken’s photo of the sunrise on the 2013 summer solstice bigger, see more in his Boat(s) slideshow, and definitely check out kenscottphotography.com to view and purchase his work.

More science on Michigan in Pictures.