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Saturday, October 22, 2016

You're So Vein: Strahler Stream Order Classification System and Open-Source QGIS

       A colorful new map shows the complicated network of rivers and streams in the contiguous United States, dominated, of course, by the Mississippi River catchment area, shown in pink below.

       The map was created by Imgur user Fejetlenfej, using open-source QGIS (Geographic Information System) software.

      The map creator also used Strahler Stream Order Classification, with higher stream orders indicated as thicker lines. 

      There are 18 major river basins in the 48 states of the contiguous US, but, as noted above, much of the map is dominated by the massive catchment area for the Mississippi River, including the Upper and Lower Mississippi River Basins, along with Missouri River Basin and the Arkansas-White-Red Basin.

      The map is not perfect (note the straight-line, perpendicular, feathery lines within the Great Lakes, rather than solid bodies of water)

as well as the inconsistencies in the Columbia River-Snake River Plain area.

        The most exciting part of the map, for me, though, is that all the data were obtained gratis and put on an open-source GIS platform. It makes a dazzling display (overlooking those few issues). And people are buying it on Etsy! Maps getting good press is always exciting. 

     Maizie (pictured here on her 10th birthday Monday) and I are off to enjoy our 80 degree October day. Maybe we'll even hike streamside ;-) with a stream of consciousness running in our heads. . .


Are you live streaming streams this week? Steph

Thursday, October 13, 2016

Vinicunca Rainbow Mountain in the Andes of Peru: Dr. Seussian Stripes

      The "Rainbow in the Mountain" of Vinicunca in the Andes in Peru is so remote, it is hard to locate on Peruvian maps. Vinicunca doesn't yet have a Wikipedia page (as of today). But, the rainbow will blow you away.

       Located in a remote part of the Andes, somewhere near Cusco, (or Cuzco), Peru, the magical sedimentary layers appear unreal.

      I looked at a few blogs and guided trips to convince myself it really is real.

 From the little geologic research I could find about the area, the Permian formations with their distinct colors of red, ochre, and turquoise sandstones and (possibly) overlying Cretaceous, limestone layers create a wondrous landscape for alpaca, llamas, and horses.

The herding communities in the region constitutes one of the few remaining pastoralist societies in the world. High mountain trails are used by these herders to trade with agricultural communities at lower elevations.

I will see if I can locate the Rainbow Mountain of Vinicunca on Google Earth in the morning. 

Have a go if you'd like!

{It's been a long day. The state of emergency declared in Ethiopia means Zoƫ will likely be coming stateside in the next 30 days. We just don't know when.}

One more look at the Seussical stripes of Rainbow Mountain in Peru!


Update: Google Earth view of Rainbow Mountain or Vinicunca

Tuesday, October 4, 2016

How to Read Red Aspen Leaves: Anthocyanins and Sun Block for Leaves

     Why do some aspen leaves turn orange or red, rather than the more usual yellow or golden? Maizie, fearless and happy pup, and I were on our 16th annual autumn pilgrimage to Hell's Hole Trail on Saturday, pondering this very point.

      Since we've hiked the same trail on or about September 30th for 16 autumns, we've seen the same aspen tree turn yellow one year and bright orange or red the next few years, and back to yellow for a few years, then back to orange.

       I wrote in a 2014 PEOTS postscript (after my sign off) about it being a very orange year (lots of carotenoids). 2015 was overall much yellower; the reds and oranges were quite rare.  How much does moisture, temperature, soil conditions, or other factors affect the yellow, orange, or red of aspen? Ready, Maizie? Lead the way!

      First, a brief photosynthesis review: As deciduous trees prepare to lose their leaves, they begin to resorb nutrients and to slow chlorophyll production, unmasking other pigments that have been present all along. Yellow and orange leaf colors are due to xanthophyll and carotenoid pigments (see below).

Here's a handy chart showing all the leaf pigments:

  • Chlorophyll for greens
  • Carotenoids for orange
  • Xanthophyll of the Carotenoid group for yellow
  • Anthocyanins for reds and purples
  • Tannins for brown as a waste product

      Reds and purples, as noted above, are due to anthocyanins and these pigments are only produced in the autumn (by some plants). It is still not clear the role these red pigments play, and why a tree would spend energy to create them at a time when they are about to drop all their leaves. Hypotheses include reducing the risk of light-induced damage to leaf cells (sort of a sun block for the leaves), protection from cold, protection from insects, and helping leaves retain water.

        Some plants almost always produce red but, in some cases like aspen, only a few trees turn red. What makes them different?

      In 1989, Kuo-Gin Chang and his research team, then at Colorado State University, analyzed the pigments of yellow and red aspen and determined that all aspen produced carotenoids, but anthocyanins were only found in red aspens. The ability to produce anthocyanins appears to be a genetic trait that some aspen trees have, but most don’t.

      However, just because a tree can produce anthocyanins doesn’t mean that it always will. The researchers followed the trees they studied for five years. The trees that started off yellow stayed yellow, but some of the trees that started off red (i.e., they produced anthocyanins) were yellow in subsequent years. This demonstrates that both genes and weather cause the red. Years that produce the best reds have warm sunny autumn days followed by cool, but not freezing, nights.

      Not only do the red pigments of the anthocyanins protect leaves from the sun they also give some species extra time to absorb their essential leaf nutrients. As chlorophyll starts to exit the leaves, anthocyanins are being created to get the leaves additional time to unload the excess nutrients. Anthocyanins are a result of excess sugars within the cells and in combination with bright light, produce red pigment. Most anthocyanins are present only in autumn. One may observe a tree turning red at first and then changing to all yellow as days lengthen and rains come. The trees then need more food supply so they go into high gear and the leaves turn yellow.

       So, clearly, Maizie and I need more data within one season to see if the reds and oranges of certain aspen turn yellow later in the autumn.

Leaving it there for now; how's your aspen?

Wednesday, September 28, 2016

Geological Society of America Meets in Denver: Paleocene-Eocene Thermal Warming and Comparisons to Today's Global Warming

      An era of skyrocketing global temperatures started with an impact bang according to research presented September 27, 2016, here in Denver at the Geological Society of America's Annual Meeting.

         Impact debris and evidence of widespread wildfires in eastern North America suggest that a large space rock hit earth around 56 million years ago at the beginning of the Paleocene-Eocene Thermal Maximum, also known as the PETM, a period of rapid warming and huge increases in carbon dioxide.

     The event is one of the closest historic analogs to modern global warming and is used to improve predictions of how earth’s climate and ecosystems will fare in the coming decades.

     Too little is known about the newfound impact to guess its origin, size or effect on the global climate, said Dr. Morgan Schaller of Rensselaer Polytechnic Institute. But it fits in with the long-standing and controversial proposal that a comet impact caused the PETM. “The timing is nothing short of remarkable,” said Schaller at the GSA meeting.

     The impact may have contributed to the rapid rise in CO2 by stirring carbon up into the atmosphere, but it was hardly the sole cause, said Sandra Kirtland Turner, a geochemist at the University of California, Riverside. Her own environmental simulations suggest that the influx of carbon that flooded Earth during the PETM probably took place over at least 2500 years, far too drawn out to be caused by a single event, she said at the same meeting.

     During the PETM, a massive influx of carbon flooded the atmosphere and earth warmed by 5 to 8 degrees Celsius to temperatures much hotter than today. That carbon dump altered the relative abundance of different carbon isotopes in the atmosphere and oceans, leaving a signal in the sedimentary record.

     While searching for that signal in roughly 56-million-year-old sediments from sites up and down the U.S. east coast, Schaller spotted microscopic glassy spheres about the size of a dust mite as seen in SEM:

      These specks resemble those blasted from previously identified large impact events.

     After switching from a black to a white sorting tray to more easily see the black debris, researchers discovered abundant charcoal pieces in the mix, as seen below in a Scanning Electron Microscope (SEM) image. That charcoal likely formed when wildfires sparked by the impact raged across the landscape.

     More evidence of the impact will help researchers to better constrain its location, scope and possible relationship to the start of the PETM, Dr. Schaller said.

Have you ever made a simple change a la "black tray to white tray switch" to discover something new?


Wednesday, September 21, 2016

Antikythera Mechanism Shipwreck Revisited: Human Skeleton Over 2,000 Years Old Discovered at Site

      Parts of a 2,000-plus-year-old skeleton have been recovered from the shipwreck which contained an early analog computer, the Antikythera Mechanism, which we discussed here at Partial Ellipsis of the Sun in 2014.

      Researchers found the skeleton last August during their ongoing excavation of the wreck, which lies on the ocean floor off the Greek island of Antikythera in the Aegean Sea.

      “Against all odds, the bones survived over 2,000 years at the bottom of the sea, and they appear to be in fairly good condition,” Dr. Hannes Schroeder, DNA expert, of the Natural History Museum in Copenhagen, Denmark, said.

     The discovery consists of a partial skull with three teeth, arm and leg bones, and several parts of ribs as reported yesterday in Nature. They are the first bones to be recovered from the wreck, particularly exciting during this era of DNA sequencing.

       The passenger or crew member “was trapped in the ship when it went down and he or she must have been buried very rapidly or the bones would have (been) gone by now.” Some of the bones remain on the seafloor, but others have been brought to the surface for analysis.

      If the research team, which is led by experts from Woods Hole, can recover DNA from the skeleton, they may be able to confirm the individual’s gender and hair and eye color, as well as his or her ethnicity and geographic origin.

      The wreck, which is believed to be of a Greek trading or cargo ship, is the largest ancient shipwreck ever discovered. Since its discovery by sponge divers in 1900, divers have recovered extraordinary artifacts including glassware, gold jewelry,

marble statues and an ancient weapon known as a "dolphin,"

a lead and iron artifact that weighs about 220 pounds. "Dolphins" were defensive weapons that were dropped from the ship’s yard, a spar on the mast, onto the deck of an attacking ship, such as a pirate vessel. 

      The Antikythera Mechanism remains the star of the seafloor find, at least so far.

       These are the best of (DNA) times. . .

Speaking of times, we are close to the 3-year anniversary of Partial Ellipsis of the Sun on October first!


Tuesday, September 13, 2016

Speaking of Geologic Time Periods Ending in E: Indian Fossils and the Spread of Primate-Like Animals: India's Island Days

      Well-preserved bones of rat-sized creatures excavated in an Indian coal mine may come from close relatives of the first primate-like animals, Iowa, USA, researchers describe.

     A set of two dozen limb fossils, dating to about 54.5 million years ago during the Eocene, raises India’s profile as a possible hotbed of early primate evolution, says biologist Dr. Rachel Dunn. 

      Bones from Vastan coal mine in Gujarat, India’s westernmost state, indicate that these small tree-dwellers resembled the first primates from as early as 65 million years ago, the scientists report in the October 2016 Journal of Human Evolution.

     These discoveries add to previously reported jaws, teeth and limb bones of four ancient primate species found in the same mine. “The Vastan primates probably approximate a common primate ancestor better than any fossils found previously,” says paleontologist and study co-author Dr. Kenneth Rose of Johns Hopkins University.

     The Vastan animals were about the size of living gray mouse lemurs and dwarf lemurs, weighing roughly 150 to 300 grams (about half a pound), the investigators estimate. 

      Most Vastan creatures possessed a basic climbing ability unlike the more specialized builds of members of the two ancient primate groups that gave rise to present-day primates, the researchers say. One of those groups, omomyids, consisted of relatives of tarsiers, monkeys and apes. 

       The other group, adapoids, included relatives of lemurs, lorises and bushbabies. The Indian primates were tree-dwellers but could not leap from branch to branch like lemurs or ascend trees with the slow-but-sure grips of lorises, the new report concludes.

      Vastan primates probably descended from a common ancestor of omomyids and adapoids, the researchers propose. India was a drifting landmass headed north toward a collision with mainland Asia when the Vastan primates were alive. Isolated on a huge chunk of land, the Indian primates evolved relatively slowly, retaining a great number of ancestral skeletal traits, the researchers propose.

      “It’s possible that India played an important role in primate evolution,” says evolutionary anthropologist Dr. Doug Boyer of Duke University. In 2010, a team led by Boyer reported that a roughly 65-million-year-old fossil found in southern India might be a close relative of the common ancestor of primates, tree shrews and flying lemurs (which glide rather than fly and are not true lemurs).

     One possibility is that primates and their close relatives evolved in isolation on the island continent of India between around 65 million and 55 million years ago, Dr. Boyer suggests. Primates then spread around the world once India joined Asia by about 50(?) million years ago.

     This is a controversial idea. An increasing number of scientists suspect primates originated in Asia. Chinese primate fossils dating to 56 million to 55 million years ago are slightly older than the Vastan primates. The Chinese finds show signs of having been omomyids.

      And in at least one respect, Dr. Boyer says, some of the new Vastan fossils may be more specialized than their discoverers claim. Vastan ankle bones, for instance, look enough like those of modern lemurs to raise doubts that the Indian primates were direct descendants of primate precursors.

      Dr. Dunn, however, regards the overall anatomy of the Vastan fossils as “the most direct evidence we have” that ancestors of early primates lacked lemurs’ leaping abilities, contrary to what some researchers have argued. 

Your thoughts? Omo or Ada? Or?

P.S. My oldest peach tree is loaded with fruit this year! They are just ripening now.