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How Hot Is Too Hot For Human Life?

Description: The breathtaking yet deadly Sulfur Springs in Ethiopia and other places in the world are the most inhospitable places on the Earth as the temperature reaches around 40-50 C on average. Such places seem more alien-like than Earth-like, but some habitation has been found in these springs despite the extreme environment that would be uninhabitable for human life. Take a read and a peek at some gorgeous pictures of the Sulfur Sands from the comfort of your phone screen rather than standing right next to the blazing heat in real life!



Welcome To Danakil Depression!


In a place of beauty near Northwest Africa, the environment represents more of a nightmare to be around: The smoldering sun blazing down on the cracked ground, lava bubbles and frizzes with concerning toxins, and continuous heat waves that leave dehydrated beings parched and loathing for cool air. Yet, the gallery of photos below represents a beautiful side of it all: the beauty of nature, geography and science!





“Danakil Depression” is a historical landmark and destination for tourists around the world, located on the Northern side of the Afar Triangle in Ethiopia. It is known for its extreme climate and environment, such as the hot weather and low elevation, making it also to be one of the hottest, lowest and poorly researched geological areas due to its extreme conditions. The name “Danakil Depression” refers to a geological depression in the Afar Triangle as a result of three tectonic plates diverging from each other in lower elevations of the Earth’s surface.


How The Earth’s Plates Created Danakil Depression


Recalling back to some simple explanations of these geography terms, the earth is theorized to be built in layers in the following order of deepest to shallowest depth: the inner core, the outer core, the mantle, and the crust. The crust of the Earth is the thinnest outmost layer and reacts with the Earth’s atmosphere and water sources to create new materials and rocks. The crust is split up into small bits called tectonic plates, which float on top of the uppermost mantle, composed of solid rocks maneuvered by malleable magma, falling under an umbrella term known as the lithosphere. The scientific theory behind tectonic plates describes these plates as the large movements of the Earth’s surface motions and formations across the continents and oceans, dating this process back three billion years ago. The driving, constant motion of the plates is the result of the flowing currents of the uppermost mantle, which happens as the temperature and age of plates change. As plates begin to wither and become colder, the plate begins to carry more density that causes the plate to sink underneath the mantle, as these plates have become denser than the mantle itself. However, this pulls the line of plates along, like a conveyor belt, causing pressure to build up. The built up pressure is released through three conventional methods: convergent, divergent, and transform boundaries. The particular case of the Afar Triangle is the phenomenal collision result of three plates diverging from each other creating volcanic activity to erupt through the gap between the three plates and make an appearance through the Earth’s surface.





When magma is near the Earth’s surface, the magma releases any compromised gases into the Earth’s atmosphere during volcanic activity, such as sulfur dioxide, the most common gas to be found in the Earth’s crust, as well as carbon dioxide, hydrogen sulphites and hydrogen halides. Additionally, the magma pushes up the salts in the underneath layers of the Earth, which causes the rocks in Danakil Depression to have a yellow/orange/green color!





Sulfur Dioxide In the Presence of Volcanos and Hot Springs


Sulfur dioxide is known to be toxic to human life and can pose imminent health hazards to humans at concentrations of around 100 parts of sulphur dioxide per million parts of air (100 ppm)! However, most sulfur dioxide in the atmosphere caused by the natural environments will likely not harm human life according to a ScienceDirect Journal by Stephen Zinder and Thomas D Brock. The sulfur dioxide can arise through a single replacement chemical reaction with the presence of iron (i) oxide in the environment. Investigated by Stephen Zinder and Thomas D Brock, at neutral or alkaline ph levels (higher than 7 on the ph scale), sulfide has shown to always oxidize with oxygen air which displaces the metal in iron (i) oxide, creating the new chemical product, sulfur dioxide. Interestingly enough, there was no correlation with the amount of sulfur dioxide being produced with habitable bacteria and other living organisms capable of oxidizing the sulfide compounds. The habitation of bacteria and other organisms in such extreme climates is an impressive observation to be made, and these species thriving in climates like Danakil Depression, are known as extremophiles.



What Extremophiles Can Do That Humans Can’t:





Danakil Depression reaches about 100 m below sea level, where magma is near the surface level, with little-to-no rainfall. The highest recorded water temperature in the Danakil Depression has reached around 90°C with high concentrations of sulfur dioxide thus making the water highly acidic. In the less extreme areas, the water temperature reaches about 40°C with a high of 55°C, and is typically a turquoise green due to a chemical reaction with copper salts. Due to the intense heat, acidic water, and high presence of sulfur dioxide, vegetation is not able to grow in these environments as these conditions are damaging to many plant’s organ systems. The human body can only handle so much heat as it is capable of handling about 44°C without going into a heatstroke. Heatstroke is a fatal advancement from heat exhaustion as the high internal temperatures inside a dehydrated body begin to affect the central nervous system by decreasing blood flow to the brain, and damaging tissue cells that could lead to kidney failure due to the lack of ability to regulate the body’s normal temperature. On the other hand, organisms known as extremophiles are known to thrive in extreme climates and actually prefer these climates. A sub-group of extremophiles are polyextremophiles, who are able to adapt and change to some physical-chemical parameters in extreme circumstances! There has not been much research done on these organisms as they are quite rare to find on Earth, but usually, these organisms are present in glaciers, extreme deserts etc. Their presence and ability to grow in extreme conditions make these creatures interesting organisms to explore and study as some researchers are linking their existence and capability to thrive as a way to explore the possibilities for humans to live in extreme conditions outside of Earth, like on Mars! While there are many dangers in going to the Danakil Depression, with some resources and research handy, many tourists pack their bags to seek for a beautiful adventure in the alien-like world and to grab some pictures! Here’s a gallery of these photos, it’s quite the sight!






Written By Elina J


Works Cited:


Alden, Andrew. “All About the Earth's Crust, and Why It Is so Important.” ThoughtCo, 2019,


Cavalazzi Professor in Geobiology and Astrobiology at the Biological, Barbara. “Ethiopia's


Inhospitable Danakil Depression Gives Us Clues about Life on Mars.” The Conversation, 2 Apr. 2017,



life-on-mars-75228.


Cumming, Vivien. “Earth - This Alien World Is the Hottest Place on Earth.” BBC, BBC, 15




Imster, Eleanor. “Inhospitable Danakil Depression Hosts Extreme Life.” EarthSky, 2 May



Petersen, Carolyn Collins. “The Danakil Depression: The Hottest Place on Earth.”



U.S. Geological Survey. “Volcano Hazards Program.” USGS, 10 May 2017, 11:23,



Zinder, Stephen, and Thomas D Brock. “Sulfur Dioxide in Geothermal Waters and Gases.”


Geochimica Et Cosmochimica Acta, Pergamon, 14 Apr. 2003,


www.sciencedirect.com/science/article/abs/pii/0016703777901879.

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