Young Sunflowers Follow the Sun, Mature Sunflowers Face East for the Warmth and Bugs (Florida Anyone?)

      Young sunflowers, as you may have observed, are heliotropic and appear to follow the sun (cue The Beatles!). However, mature sunflowers continue to face east once the stalk has matured to gather maximum warmth and pollinators (cue the Beetles!).

       Young sunflowers (Helianthus annuus) grow better when they track the sun’s daily motion from east to west across the sky. An internal clock helps control the behavior, Dr. Stacey Harmer and researchers report in 8/5/16 issue of Science.

      Depending on the time of day, certain growth genes appear to be activated to different degrees on opposing sides of young sunflowers’ stems. The east side of their stems grow faster during the day, causing the stems to gradually bend from east to west. The west side grows faster at night, reorienting the plants to prepare them for the next morning. “At dawn, they’re already facing east again,” says Harmer, University of California, Davis. The behavior helped sunflowers grow bigger.

     Young plants continued to grow from east to west each day even when their light source didn’t move. So Harmer and her colleagues concluded that the behavior was influenced by an internal clock like the one that controls human sleep/wake cycles, instead of being solely in response to available light. 

     That’s probably advantageous, Harmer says, “because you have a system that’s set up to run even if the environment changes transiently.” A cloudy morning doesn’t stop the plants from tracking the sun, for instance.

     Contrary to popular belief, mature sunflowers don’t track the sun — they perpetually face east. That’s probably because their stems have stopped growing. But Harmer and her colleagues found an advantage for the fixed orientation, too: Eastern-facing heads get warmer in the sun than westward-facing ones and attract more insects.

       I was happy to find a sunny topic for this week's PEOTS. This one is for Zoë.  

Sunnily,
Steph

Revisiting Iceland: A Kentucky-Sized Place Where Geology is in Your Face at Every Turn

         A friend's trip to Iceland the past two weeks has reinspired a look at this Kentucky-sized land. My friend's description of her trip included words about geology staring one in the face at every turn. Young, changing, extraordinary geology is located next to the much older geology of Greenland.

     "Iceland is a manifestation of plate tectonic activity along a 10,000-mile underwater mountain range called the Mid-Atlantic Ridge. The island, which is about the size of the state of Kentucky, is only 15-20 million years old, making it one of the youngest landmasses of its size in the world, according to Ari Trausti Guðmundsson, a geophysicist, poet, and former Iceland presidential candidate."

     “If you hop over to Greenland, the bedrock is over 3,000 million years old,” says Guðmundsson, who guided Pitcairn during his expedition to Bárðarbunga and wrote the text, including 120 poems, in his book. “In comparison, Iceland is an infant.”

     "The Mid-Atlantic Ridge gives rise to Iceland’s volcanoes, one of its signature geological features. The country boasts 30 volcanic systems, which contain hundreds of active volcanoes. The natural upwelling of magma from beneath the ridge, as well as a mantle plume located almost right under the middle of the country, send billions of tons of lava surging through the bedrock annually, causing the country to expand about one inch per year, on average, according to Guðmundsson.

       Additional information about this geologist's dream country is located at this link. Hoping to get to Iceland before too many of the glaciers have melted.

        I am also fascinated by the unusual diacritical marks in the place and author names. It's also fun to see a geologist poet who ran for the presidency of Iceland! With a small population, I guess residents wear many hats. . .

        How about you; what about Iceland fascinates you?

Steph

"Fire Stranger" Pyroxene and Young Martian Clay

       Pyroxenes are isosilicates which are one of the most common constituents of the lithosphere of earth. They are also prominent minerals in the uplifted rocks on Mars.

       The name pyroxene comes from the Greek words for fire (πυρ) and stranger (ξένος). Pyroxenes were so named because of their presence in lavas, where they are sometimes present as crystals in volcanic glass. It was originally assumed they were impurities in the glass, hence the name "fire strangers". However, they are merely early-forming minerals that crystallized before the lava erupted.

      The most recent data from Mars show that clay found at impact sites near uplifted pyroxene uplifts is believed to be clay-rich impact melt material (i. e. authigenic), rather than clay pulled to the surface by impacts. This authigenic clay is now dated at 2 billion years or less rather than 3.7 billion years, as previously thought.

Brown University geologists, not affiliated with Coffee ;-), describe their research in a press release yesterday.

And, interestingly a hexagonal pattern shows up in craters on Mars as well:

     Mars and earth seem more and more similar every day. . .

       I am taking a Wild Clay painting class next month with a friend's brother here in Colorado. It may come in especially handy, if I ever go to Mars to check out the melted, wild, young clay.

Ka-O, don't be a fire stranger,
Steph

Bonus: Cliff Palace, Mesa Verde National Park, CO, with 70 lanterns, December 2015