The Saltiest Lake on Earth

The Saltiest Lake on Earth

New findings that have implications for similar briney features, known as recurring slope lineae (RSL), found on Mars. “Thus, if RSL and chloride-bearing basin floor units on Mars do represent DJP-like hydrologic systems, they may have significant potential for hosting resilient microbiota, and the most habitable places on Mars may mimic the least habitable places on Earth.”

Originally shared by Gary Ray R

The Lake in Antarctica That Does Not Freeze

There are lakes on the frozen continent of Antarctica.  Most have thick layers of ice year round but there is one that has so much salt that the water does not freeze, even in the frigid depths of winter in the coldest area on earth.  Well, not a really big lake but just a pond; it is the Don Juan Pond located in the west end of Wright Valley (South Fork), Victoria Land, Antarctica.  Where does the salt come from?

Don Juan Pond, also called Lake Don Juan, is a small and very shallow hypersaline lake in the west end of Wright Valley (South Fork), Victoria Land, Antarctica, 9 kilometers (5.6 mi) west from Lake Vanda. It is wedged between the Asgard Range in the south and the Dais in the north. On the west end there is a small tributary and a feature that has been described as a rock glacier. With a salinity level of over 40%, Don Juan Pond is the saltiest known body of water on Earth.  ⓐ

Don Juan Pond was discovered in 1961. It was named for two helicopter pilots, Lt Don Roe and Lt John Hickey, who piloted the helicopter involved with the first field party investigating the pond. On that initial investigation, the temperature was −30 °C (−22 °F) and the water remained in a liquid state.  ⓐ

While discovered in 1961, it is in the news now because of the images just released by NASA taken by the Earth Observatory satellite.  One of the images is shown below on the right.

 

The image on the left is from the 2013 study done by researchers by James Dickson and James Head from Brown, Joseph Levy from Oregon State, and David Marchant from Boston University.  They were investigating the source of the calcium chloride salt. (both pictures are high resolution so have a closer look)

The research represents the most detailed observations ever made of Don Juan Pond. “It was a simple idea,” Dickson said of the team’s approach. “Let’s take 16,000 pictures of this pond over the course of two months and then see which way the water’s flowing. So we took the pictures, correlated them to the other measurements we were taking, and the story told itself.”  ⓑ

Using time lapse photography and other data, the researchers show that water sucked out of the atmosphere by parched, salty soil is the source of the saltwater brine that keeps the pond from freezing. Combine that with some fresh water flowing in from melting snow, and you’ve got a pond able to remain fluid in one of the coldest and driest places on Earth. And because of the similarities between the Dry Valleys and the frozen desert of Mars, the findings could have important implications for water flow on the Red Planet both in the past and maybe in the present.  ⓑ

What the pictures showed was that water levels in the pond increase in pulses that coincide with daily peaks in temperature, suggesting that the water comes partly from snow warmed just enough by the midday sun to melt. But that influx of fresh water doesn’t explain the pond’s high salt content, which is eight times higher than that of the Dead Sea. For that explanation, the researchers looked to a second source of liquid documented in the photos.  ⓑ

The second source comes from a channel of loose sediment located to the west of the pond. Previous research had found that sediment to be high in calcium chloride salt. To see if that was the source of the pond’s salt, the researchers set up a second time-lapse camera to monitor the channel and synchronized the pictures with data collected from nearby weather stations.  ⓑ

The pictures show dark streaks of moisture called water tracks forming in the soil whenever the relative humidity in the air spiked. Similar water tracks also form on a cliff face north of the pond. What’s forming these tracks is the salt in the soil absorbing any available moisture in the air, a process known as deliquescence. Those water-laden salts then trickle down through the loose soil until they reach the permafrost layer below. There they sit until the occasional flow of snowmelt washes the salts down the channel and into the pond.  ⓑ

When the team saw how closely correlated the appearance of water tracks was to their humidity readings, they knew the tracks were the result of deliquescence and that the process was key to keeping the pond salty enough to persist.  ⓑ

The findings refute the dominant interpretation of Don Juan Pond’s origin. Since the pond’s discovery in 1961, most researchers had agreed that its briney waters must be supplied mainly from deep in the ground. However, these new images show no evidence at all that groundwater contributes to the pond.  ⓑ

ⓐ  Wiki

http://en.wikipedia.org/wiki/Don_Juan_Pond

ⓑ  News from Brown

How the world’s saltiest pond gets its salt

https://news.brown.edu/articles/2013/02/antarctica

Scientific Reports (open access)

Don Juan Pond, Antarctica: Near-surface CaCl2-brine feeding Earth’s most saline lake and implications for Mars

http://www.nature.com/srep/2013/130130/srep01166/full/srep01166.html

Live Science

World’s Saltiest Body of Water Seen from Space (Photo)

http://www.livescience.com/49284-worlds-saltiest-body-of-water.html?

Image on right,

Credit: NASA Earth Observatory image by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team and the U.S. Geological Survey.  

NASA Earth-Observing Satellite photo showing Don Juan Pond, a network of channels carved into the bedrock east of the Wright Upper Glacier, and the frozen Lake Vanda to the northeast of the pond.

Image on left,

Credit: Geological Sciences/Brown University

A camera installed above Don Juan Pond in Antarctica’s McMurdo Dry Valleys took 16,000 images in two months, documenting geological processes in real time.

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7 Comments


  1. 再生核研究所声明199(2015.1.15) 世界の数学界のおかしな間違い、世界の初等教育から学術書まで間違っていると言える ― ゼロ除算100/0=0,0/0=0


    ゼロ除算は 西暦628年インドでゼロが文献に記録されて以来、問題とされてきた。ゼロ除算とは、ゼロで割ることを考えることである。これは数学の基本である、四則演算、加法、減法、乗法、除法において、除法以外は何時でも自由にできるのに、除法の場合だけ、ゼロで割ることができないという理由で、さらに物理法則を表す多くの公式にゼロ除算が自然に現れていることもあって、世界各地で、今でも絶えず、問題にされていると考えられる。― 小学生でも どうしてゼロで割れないのかと毎年、いろいろな教室で問われ続いているのではないだろうか.


    これについては、近代数学が確立された以後でも、何百年を越えて 永い間の定説として、ゼロ除算は 不可能であり、ゼロで割ってはいけないことは、初等教育から、中等、高校、大学そして学術界、すなわち、世界の全ての文献と理解はそうなっている。変えることのできない不変的な法則のように理解されていると考えられる。


    しかるに2014年2月2日 ゼロ除算は、可能であり、ゼロで割ればゼロであることが、偶然発見された。その後の経過、背景や意味付け等を纏めてきた:


    再生核研究所声明 148(2014.2.12) 100/0=0,  0/0=0 - 割り算の考えを自然に拡張すると ― 神の意志


    再生核研究所声明154(2014.4.22) 新しい世界、ゼロで割る、奇妙な世界、考え方


    再生核研究所声明157(2014.5.8) 知りたい 神の意志、ゼロで割る、どうして 無限遠点と原点が一致しているのか?


    再生核研究所声明161(2014.5.30)ゼロ除算から学ぶ、数学の精神 と 真理の追究


    再生核研究所声明163(2014.6.17)ゼロで割る(零除算)- 堪らなく楽しい数学、探そう零除算 ― 愛好サークルの提案


    再生核研究所声明166(2014.6.20)ゼロで割る(ゼロ除算)から学ぶ 世界観


    再生核研究所声明171(2014.7.30)掛け算の意味と割り算の意味 ― ゼロ除算100/0=0は自明である?


    再生核研究所声明176(2014.8.9) ゼロ除算について、数学教育の変更を提案する


    Announcement 179 (2014.8.25): Division by zero is clear as z/0=0 and it is fundamental in mathematics


    Announcement 185 : The importance of the division by zero $z/0=0$


    再生核研究所声明188(2014.12.15)ゼロで割る(ゼロ除算)から観えてきた世界


    再生核研究所声明190(2014.12.24)


    再生核研究所からの贈り物 ― ゼロ除算100/0=0, 0/0=0


    夜明け、新世界、再生核研究所 年頭声明


    ― 再生核研究所声明193(2015.1.1)― 


    再生核研究所声明194(2015.1.2)大きなイプシロン(無限小)、創造性の不思議


    再生核研究所声明195(2015.1.3)ゼロ除算に於ける高橋の一意性定理について


    再生核研究所声明196(2015.1.4)ゼロ除算に於ける山根の解釈100= 0x0について


    ところが、気づいてみると、ゼロ除算は当たり前なのに、数学者たちが勝手に、割り算は掛け算の逆と思い込み、ゼロ除算は不可能であると 絶対的な真理であるかのように 烙印を押して、世界の人々も盲信してきた。それで、物理学者が そのために基本的な公式における曖昧さに困ってきた事情は ニュートンの万有引力の法則にさえ見られる。


    さらに、誠に奇妙なことには、除算はその言葉が表すように、掛算とは無関係に考えられ、日本ばかりではなく西欧でも中世から除算は引き算の繰り返しで計算されてきた、古い、永い伝統がある。その考え方から、ゼロ除算は自明であると道脇裕氏と道脇愛羽さん6歳が(四則演算を学習して間もないときに)理解を示した ― ゼロ除算は除算の固有の意味から自明であり、ゼロで割ればゼロであるは数学的な真実であると言える(声明194)。数学、物理、文化への影響も甚大であると考えられる。


    数学者は 数学の自由な精神で 好きなことで、考えられることは何でも考え、不可能を可能にし、分からないことを究め、真智を求めるのが 数学者の精神である。非ユークリッド幾何学の出現で 絶対は変わり得ることを学び、いろいろな考え方があることを学んできたはずである。そのような観点から ゼロ除算の解明の遅れは 奇妙な歴史的な事件である と言えるのではないだろうか。


    これは、数学を超えた、真実であり、ゼロ除算は不可能であるとの 世の理解は間違っている と言える。そこで、真実を世界に広めて、人類の歴史を進化させるべきであると考える。特に声明176と声明185を参照。ゼロ除算は 堪らなく楽しい 新世界 を拓いていると考える。


    以 上

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