Oxygen Blue Sky and Complex Life Exist Because of a Bacteria

Super fact 72 : About three billion years ago Cyanobacteria evolved a new type of photosynthesis that used sunlight, water, and carbon dioxide to create energy, while releasing oxygen as a waste product. This transformed the atmosphere and enabled complex life by allowing aerobic respiration to evolve. This invention turned the sky blue, gave us the protective ozone layer, but also caused climate change resulting in massive extinctions.

A microscopic photo of Cyanobacteria. They look like green blobs with small nucleuses. | Oxygen Blue Sky and Complex Life Exist Because of a Bacteria
An example of a Cyanobacteria. From Wikipedia. Luke Thompson from Chisholm Lab and Nikki Watson from Whitehead, MIT, CC0, via Wikimedia Commons

Cyanobacteria, also known as blue-green algae, are bacteria capable of oxygenic photosynthesis. Between 3.4 and 2.5 billion years ago they developed a new and very effective form of photosynthesis, which took advantage of highly abundant resources, using sunlight, water, and carbon dioxide turning it into sugar and releasing oxygen as byproduct. This is referred to as the Great Oxidation Event. You can read more about this event here, here, here, here, here, or in the book Becoming Earth by Ferris Jabr.

The atmosphere prior to the Great Oxidation Event was primarily composed of volcanic gases including nitrogen, carbon dioxide, water vapor, methane and ammonia, but almost no free oxygen. The Great Oxidation Event changed all this, but it likely took at least 200 million years.

Labeled educational bacteria internal structure scheme.
Cyanobacteria vector illustration. Biological blue green algae diagram with carboxysome, thylakoid and phycobilisome parts location inside cell. Asset id: 1687712761 by VectorMine

A Microbial Great Extinction and Snowball Earth

Oxygen was a toxic gas to many early microbes forcing them to adapt or perish. In addition, the change in the atmospheres composition changed the climate, resulting in a severe global cooling referred to as Snowball Earth. This caused a great extinction, perhaps the most severe extinction in Earth’s history. It is not included among the five mass extinction events in Earth’s history because it happened very early in Earth’s history when only primitive microbial life existed and fossil evidence from that time is nearly non-existent. The definition of a mass extinction event is that at least 75% of the world’s species are lost during a short period of time – geologically speaking. This period is not clearly defined but often defined to be two million years. It is very difficult to determine whether the great extinction following the Great Oxidation Event qualifies as a mass extinction event. To read about mass extinctions click here.

Ancient Earth almost entirely covered by ice and white snow. | Oxygen Blue Sky and Complex Life Exist Because of a Bacteria
Proterozoic era in the history of the Earth. Snowball earth. Global glaciation of the Earth. Asset id: 2010272753 by Elena Kelman

The Ozone Layer and the Blue Sky

Oxygen is also responsible for formation of the ozone layer in the atmosphere. The UV radiation from the sun split oxygen molecules, which consist of two oxygen atoms, into two separate atoms of oxygen, which then reacted with another oxygen molecule to generate ozone, and oxygen molecule consisting of three oxygen atoms. Ozone acts as a natural sunscreen to prevent harmful UV radiation from reaching the earth. Therefore, oxygen not only enables land dwelling complex multicell organisms to exist by allowing aerobic respiration to evolve, but also by protecting life from too much UV radiation.

As mentioned above, the atmosphere prior to the Great Oxidation Event was primarily composed of volcanic gases and almost no free oxygen. The color of the sky was likely orange, brown. As oxygen replaced the existing gases the sky slowly turned blue. Oxygen molecules along with Nitrogen molecules scatter blue light from the sun through a process called Rayleigh scattering, making the sky appear blue.

Cyanobacteria and The Great Oxygenation Event

It should be noted that there were other geological and biological processes that were responsible for this permanent shift in the Earth’s system, including changes in the composition of volcanic emissions and chemical reactions that allowed atmospheric hydrogen to escape to space, leaving behind an excess of oxygen molecules. However, whatever the exact mix of mechanisms, cyanobacteria were undoubtedly a critical source of accumulating oxygen. It is possible that tectonic activity altered the cycling and distribution of phosphorus and other nutrients essential for cyanobacteria. To read more see the book Becoming Earth by Ferris Jabr.

To see the other Super Facts click here

The Extinction Rate is Much Higher Than the Natural Baseline Rate

Super fact 71 : Based on the fossil record today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate.

Animals included in the watercolor painting include Teratorm, Mammoth, Macrauchenia, Glyptodon, Smilodon, and Andrewsarchus. | The Extinction Rate is Much Higher Than the Natural Baseline Rate
Collection of watercolor prehistoric and now extinct animals isolated on a white background. Hand painted illustration of Ice Age. Asset id: 2169205593 by Ekaterina Glazkova

Estimating the extinction rate is a complicated task that requires some assumptions and estimations. This article from the National Library of Medicine use what it claims to be conservative estimates, which would tend to minimize evidence of an emerging mass extinction. Despite that fact the average rate of vertebrate species loss over the last century is up to 100 times higher than the extinction rate without/before humans (background rate). Other sources claim an extinction rate that is 1,000 or even 10,000 the background rate.

To put some specific numbers on what a high extinction rate means, scientists count 881 animal species are known to have gone extinct since around 1500. If we include animal species that scientists suspect might be extinct, that number shoots up to 1,473. You can read more on the issue here or here or here.

A black and white photo of Two Tasmanian Tigers. The Tasmanian Tigers had stripes on their back.
Two Tasmanian Tigers. The Tasmanian Tiger or Thylacine was hunted to extinction. Benjamin, the last Tasmanian Tiger, died in 1936 in the Beaumaris Zoo in Tasmania. Baker; E.J. Keller., Public domain, via Wikimedia Commons

What is clear is that the current extinction rate is much higher than what is typical and we humans are the cause. This came as a shock to me the first time I found out about it, and it is certainly an important topic, and therefore a super fact. It is true, surprising to many, and important.

Those who want to minimize the problem with the ongoing extinctions often point out that extinctions are a natural part of evolution and that throughout Earth’s history up to around 98% of all species that have ever existed are now extinct. In my opinion, that argument fails to consider the enormity of Earth’s four billion year natural history. A lot of evolution happened during that time.

Modern humans have only been around 300,000 years, or 0.0075% of that time, a tiny blip in time. Human civilization has only been around for 12,000 years, or 0.0003% of that time, an even tinier blip in time. Like comparing an ant head to a mile. Us having a large negative impact on the natural world in such an extremely short time is quite notable.

By considering the extinction rate you get a better idea of the scope of the problem. The fact that the extinction rate today is significantly higher than the expected natural rate and that the primary cause of modern extinctions is human impact as opposed to natural phenomena, makes it a case for concern. To read about a related issue, “The Wild Mammal Biomass Has Substantially Declined”, click here.

The color photo shows a close up of a giant tortoise. | The Extinction Rate is Much Higher Than the Natural Baseline Rate
Lonesome George at the Charles Darwin Research Station in 2006, the last known individual of his species of Galápagos tortoise. https://www.flickr.com/photos/mikeweston/, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0&gt;, via Wikimedia Commons

The Five Past Mass Extinction Events

Over the last 440 million years life on Earth has experienced five so called mass extinctions. A mass extinction event is when at least 75% of the world’s species are lost during a short period of time – geologically speaking. This period is not clearly defined but often defined to be two million years. Two million years may seem like a long time, but geologically speaking, it is a short time.

3D illustration showing two carnivorous dinosaurs and two large herbivores looking up at a burning asteroid.
Extinction of the dinosaurs when a large asteroid hits earth 66 million years ago. It was the last mass extinction event. Asset id: 2196200279 by funstarts33

The five mass extinction events were:

Below is an overview of the five big mass extinctions in Earth’s history. The graph is from Our World in Data.

The graph shows extinction rates going up and down with five tall peaks representing mass extinction events.
The Big Five Mass Extinctions in Earth’s History. A mass extinction is defined by the loss of at least 75% of species within a short period of time (geologically, this is around 2 million years). Extinctions are a natural part of evolution, but background rates are typically less than 5 families extinct per million years. Sources Barnosky et al (2011). Howard Hughes Medical Institute: McCallum (2015). Vertebrate biodiversity losses point to a sixth mass extinction. From Our World in Data.
A stunning AI generated illustration of a woolly mammoth standing on a snowy landscape during a vibrant sunset with northern lights in the sky. | The Extinction Rate is Much Higher Than the Natural Baseline Rate
Are We in the Middle of a Sixth Mass Extinction ?
A Glyptodon walking across an empty prairie.
3D illustration of a Glyptodon, also extinct, Asset id: 495169627

Biodiversity experts have estimated that about 30% (uncertainty range: 16–50%) of species have been globally threatened or driven to extinction since the year 1500. 30% globally threatened or extinct is not 75% that are actually extinct, but in just 500 years that looks like a quick start on a mass extinction. It should be noted that 500 years is just 0.025% of two million years. Issues such as deforestation, chiefly the result of replacing forests with agriculture, overexploitation, and global warming / climate change are driving extinctions and represent big biodiversity threats in the near future.

A northern white Rhino is grazing green grass at a zoo.
The Northern white rhino subspecies, the second-largest land mammal after elephants, has no hope of recovery after the last male died in 2018. Only a female and her daughter are left. The photo is of Angalifu, a male northern white rhinoceros at the San Diego Zoo Safari Park. Angalifu died of natural causes at the age of 44 on 14 December 2014. Sheep81, Public domain, via Wikimedia Commons.

This is why there is talk about the so called Holocene or Anthropocene extinction and it possibly being a sixth mass extinction, this one being human caused. It should be noted that there are credible sources that question whether we are at the cusp of a sixth mass extinction event.

Posting this on Thanksgiving Day may seem awkward. However, whether there will be a human caused sixth mass extinction or not depends on us, and it looks like more people want to protect our natural world. Many animals, such as the giant panda, bald eagle, the sea otter, black footed ferret, the Peregrine falcon, the blue whale, Rodrigues fruit bat, the Island night lizard, and the California condor, have been saved from extinction through conservation efforts like habitat restoration, anti-poaching laws, captive breeding programs, and reintroduction to the wild. Perhaps we are turning things around. We should give thanks to all who care.

To see the other Super Facts click here

The Wild Mammal Biomass Has Substantially Declined

Super fact 70 : Wild mammals have declined by 85% since the rise of humans even as the total mammal biomass has nearly tripled. The result is that only 4-5% of the total biomass of mammals are wild animals. The rest are humans and livestock.

Pie chart shows that Livestock, mostly cattle and pigs, corresponds to 60% of the mammal biomass, humans are 36%, and wild mammals are 4%. | The Wild Mammal Biomass Has Substantially Declined
Livestock, mostly cattle and pigs, corresponds to 60% of the mammal biomass, humans are 36%, and wild mammals are 4%. The data is taken from this article.

As stated, mammal biomass has declined by 85% since the rise of humans. This is despite a threefold increase in mammal biomass over the last 200 years. However, this increase is almost entirely due to the growth of human and livestock populations. The result is that only 4-5% of the total biomass of mammals are wild animals. Another result is that Earth’s wild land mammals now make up just 2% of the mammal kingdom. You can read more here, or here, or here, and more in depth here.

Humans are 36% of the mammal biomass, Sheep is 4%, Livestock and pets 59%, including 2% dogs, 3% pigs, goats 3%, cattle 38%, and buffalo 6%
Humans and our livestock dominate global mammal biomass. Biomass is the total weight of each animal group. It’s calculated by multiplying an estimate of the total number of individuals by their average mass. Shown is each group’s share of global mammal biomass. This graph is taken from Our World In Data.

I think this is a super fact because we know it is true, and this huge and extremely rapid change of Earth’s fauna (from a geological timescale) is certainly important, and yet I think it comes as a surprise to many people. I often see the argument that humans have been great for animals because there are many more of them and the mammal biomass has tripled. That argument leaves out the part about the increase in mammal biomass coming from domesticated animals while wild animals have been disappearing. One question that comes to mind is whether life at the cramped factory farm is better than the life as a wild animal.

Wild Mammal Biomass Data

Below are a couple of graphs displaying some additional information on wild mammal biomass.

The graph shows that even hoofed mammals is a big group consisting of 49% of the wild mammal biomass. Rodents are 16% and elephants are 8%, bats are 7%, Marsupials are 7%, and primates are 4%, carnivores 3%, rabbits 1%, and other mammals 4%.
The distribution of the world’s wild land mammal biomass. The graph is taken from Our World in Data.

Another thing to note is that the wild animal biomass is very concentrated to just a few species. Considering that there are between 6,500 and 6,800 recognized mammal species in the world, it is quite remarkable that only 10 species make up 40% of the mammal biomass.

White-tailed deer is 12%, Wild boar is 8%, African Savanna Elephant is 6%, Eastern gray kangaroo is 2%, Mule deer is 2%, Moose is 2%, Red Deer is 2%, European roe deer is 1.8%, Red Kangaroo is 1.8%, and the Common Warthog is 1.4%.| The Wild Mammal Biomass Has Substantially Declined
Just 10 species make up around 40% of wild mammal biomass on land. The graph is taken from Our World in Data.

Reasons for Decline of Wild Animal Biomass

This decline of wild mammal biomass is primarily caused by human activity, including hunting, habitat loss and degradation from agriculture and urbanization, climate change, and pollution. This human-driven extinction event is the result of a rapidly growing human population and its increased consumption of natural resources, leading to widespread disruption of ecosystems and dramatic declines in wild mammal populations. It should be mentioned that the extinction of large mammals such as mammoths, American mastodon, giant ground sloths and glyptodonts was likely aided by human hunting in prehistoric times. The largest mammals have always been at the greatest risk for extinction and that is still true today.

A stunning AI generated illustration of a woolly mammoth standing on a snowy landscape during a vibrant sunset with northern lights in the sky.
Woolly mammoth, now extinct, Asset id: 2571557381 by Wirestock Creators.
A Glyptodon walking across an empty prairie. | The Wild Mammal Biomass Has Substantially Declined
3D illustration of a Glyptodon, also extinct, Asset id: 495169627
To see the other Super Facts click here

Polar Nights Are Phenomenal and Cover a Large Area

Super fact 69 : Polar nights happen in the regions north of the Arctic Circle and south of the Antarctic Circle. Together the two polar regions cover an area double as large as the United States, and it includes a population of millions of people. During a polar night the sun does not rise for days, or months, up to six months.  The polar nights are special, not just for the daytime darkness, but for the spectacular aurora borealis, the starlit skies, the extremely clear air, and the fact that people often lose track of time during polar nights.

It should be noted that even though the sun never rises during the polar night it may not be totally dark during the entire polar night. Part of the time you may get some light in the middle of the day, what is called polar twilight (nautical twilight or astronomical twilight). Nautical twilight tends to be bluish as shown in the photo below.

Characteristic nautical (blue) polar twilight in Longyearbyen, Svalbard, Norway. Bjørn Christian Tørrissen, CC BY-SA 3.0
Characteristic nautical (blue) polar twilight in Longyearbyen, Svalbard, Norway. Bjørn Christian Tørrissen, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0&gt;, via Wikimedia Commons

When our kids were young, we visited the Ice Hotel in Jukkasjärvi in northern Sweden. We went in March, during the American spring break, which was not during the polar night, so we did not experience it then. The polar night in Jukkasjärvi will begin December 5, 2025, or December 10, 2025, depending on how you count, and end at the beginning of January. However, the Ice Hotel was a fun way to experience a polar region. When I did my Swedish army service I spent the winter in the forest around that area, and even further north, and I experienced the Polar Night firsthand,

Photo is of a large ice table and ice chairs located in the middle of the lobby, which is filled with tall pillars made of ice at the ice hotel. Polar Nights Are Phenomenal and Cover a Large Area
The lobby of the ice hotel. Our kids are sitting around a table of ice. A chandelier of ice is hanging above the table. The light is from fiber optics, so the ice won’t melt.

During my army service we stayed in tents in the forest far away from villages and cities and we often did not use any lights. The result was that it was incredibly dark most of the time. It was so dark that I could not see my own hand if I held it right in front of my face. The upside was that the sky was filled with thousands of stars on a clear night. It is estimated that you can see between 2,500 to 5,000, even 10,000, stars in the sky with the naked eye if you have good vision and it is completely dark. You could also see the Milky Way Galaxy very clearly and easily, as well as the Andromeda Galaxy, meteors, comets, satellites, not to mention the most spectacular aurora borealis that you can see anywhere on earth. That certainly beats the 14 stars and 3 planets that you can see with the naked eye on a clear night here in Dallas, Texas, where I live now.

Stars in the sky. Blue night panorama, a universe full of stars, nebula and galaxies | Milky way sky on dark background, and a lot of stars.
Milky way sky on dark background, and a lot of stars. Asset id: 2524020369 by MR.PRAWET THADTHIAM

On one occasion I was standing guard outside the camp. We were pretending that we were at war with the Soviet Union. It was minus 40 degrees, and they forgot about me. I stood there alone in the darkness and the extreme cold for more than three hours. This was considered dangerous. The rule was no more than one hour out in the cold at a time. Once they discovered that I had been there for more than three hours they came to get me, and they apologized profusely. They were happy that I was not hurt. However, I did not mind, because my night sky view was spectacular. The night sky was so spectacular, it was to die for.

If it is cloudy and you are far from any civilization it may be pitch black in the afternoon. Even if it is not cloudy but the moon is not out it will be pitch black later in the afternoon. In addition, the air is very clear during the polar night, because the cold sunless Arctic air often contains almost no moisture and the visibility stretches for 100 miles. If you want to remain unseen in this situation it is very important to understand that even the tiniest light will be very visible, far away.  Our platoon did an experiment. Someone lit a cigarette about one mile away and we could very easily see the bright cigarette even through the forest. The lesson was, No Cigarettes, and No lights!

Stunning aurora borealis lights up the night sky with vibrant colors, creating a mesmerizing natural display in the Arctic wilderness. | Polar Nights Are Phenomenal and Cover a Large Area
Aurora Borealis are often spectacular in the polar regions, especially during the polar night. Asset id: 2499746583 by HappyVibeArt

I consider this a super fact because the polar night is a surprising phenomenon to those who do not know much about the arctic and my claims above are true and important since the polar regions are large and under threat from climate change / global warming.  The polar regions and thereby the polar night also cover an area that is not small, and four million people live there.

Partial map of the northern hemisphere focused on the polar circle.
The Arctic Circle, at roughly 66.5° north, is a commonly-accepted boundary of the Arctic waters and lands. CIA World Fact Book, Public domain, via Wikimedia Commons.

The Midnight Sun

I can add that in the summer (northern hemisphere) you have the opposite phenomenon with the midnight sun. Just like the polar night can cause people to lose track of time so can the midnight sun. When we visited northern Sweden with our niece Jessica for my brother’s wedding, we had what is called midnight sun. Jessica was nine years old at the time. A couple of hours after we had gone to sleep Jessica woke me up “wake up Thomas, it is time to go out and play”. I protested, no it is not, it is one a clock at night and we are going to sleep. Jessica protested, she said, “No the sun is up, it is morning it is time to play”.

So, I said “Jessica, let me explain something to you. This is northern Sweden in June and here the sun is up in the middle of the night, and we are not going outside to play in the middle of the night.” After that my wife went out to play with Jessica, but I refused to go out and play at one o clock at night.

Ice Hotel Photos

Finally, I just wanted to include a few of my photos from the Ice Hotel, just for fun.

He is standing and kicking with his feet to move forward with the sled. He is passing in front of the ice theater. | Polar Nights Are Phenomenal and Cover a Large Area
Our son David with one of the kick sleds called “spark”.
A photo of an ice table and 7 instruments made of ice standing on an ice stage.
This is a photo of the ice instruments standing on the ice stage.
My wife and three children are sitting on a dog sled and looking into the camera.
We are going on a dogsled tour. The ice theater is in the background, and you can see part of the ice hotel on the right.
The kids had a lot of fun during the dogsled tour. | Polar Nights Are Phenomenal and Cover a Large Area
You can see ten dogs and the sled with us on top of it. On the left is a kåta, a movable Sami structure (indigenous arctic Scandinavian people). It is like a Tipi.
To see the other Super Facts click here

Ten Amazing Fish Facts

Esther’s writing prompt: November 12 : Fish

Click here or here  to join in.

This is not a super fact but a collection of interesting facts about Fish. They are not very important facts but amazing facts.

Freshwater fish Riffle minnow (Alburnoides bipunctatus) underwater photography. Minnow in clean water and nature habitat. Natural light. Lake and river habitat. Wild animal. Underwater photo of fish. | Ten Amazing Fish Facts
Minnows Asset id: 1182854671 by Rostislav Stefanek

Most Fresh Water Fish would die from dehydration if put in Sea Water

Most freshwater fish would die from dehydration if placed in seawater due to a process called osmosis. The same is true for saltwater fish placed in freshwater.  There are a few exceptions. So called euryhaline species are able to more or less handle both freshwater and seawater, an example is salmon. It is also why freshwater fish native to oceanic islands like Hawaii are euryhaline species. Freshwater fish that are not euryhaline species cannot travel to oceanic islands.

What is a Fish?

A fish is a vertebra (has a backbone and a brain protected by a braincase) that is aquatic, lives in water, has gills, fins, scales and is cold blooded. Dolphins, whales, jellyfish, and starfish are not fish.

Some fish have both gills and lungs

Lungfish have both gills and lungs. Their unique respiratory system allows them to breathe underwater with their gills and also breathe air from the surface with their lungs. Some species of lung fish can survive on land for several months.

Lung fish resting close to the bottom of the sea. The exact species is Neoceratodus forsteri (Australian lungfish).
Queensland lungfish, Mitch Ames, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons

Fish Can Be Raining from the Sky

Tornadoes over water have sometimes picked up both water and fish causing fish to rain down over land.

The illustration depicts a tornado / waterspout over land with lots of orange fish raining down.
Fish raining from the sky. Picture generated with the help of ChatGPT

Mudskippers the land dwelling fish

Mudskippers are fish that spend most of their time on land. It can walk on land, jump, and climb trees, by using their strong pectoral fins like legs and their tails as a lever. They breathe air through their skin and gill chambers. Below is a four minute video featuring mudskippers.

Fish the First Vertebra on Earth

Fish appeared more than 500 million years ago during the Cambrian period. They are believed to be the first vertebrates on Earth. They lay the foundation for the diverse array of vertebrate life that has since populated the planet’s ecosystems.

Some Fish can make Light

Anglerfish are deep sea fish that produce their own light using bacteria. The dangling glowing light attracts prey. Some species of angler fish live only 200 meters down in the sea while other species live as far down as 3,300 meters (11,000 feet).

Angler fish on background realistic illustration isolate. Scary deep-sea fish predator. Deep sea fish monster. | Ten Amazing Fish Facts
Angler fish on background realistic illustration isolate. Scary deep-sea fish predator. Deep sea fish monster. Asset id: 2134226987 by Konstantin G

Some Fish know how to use Tools

Wrasse are fish that use rocks as anvils to crack shells. They grab hard-shelled prey like crabs and mollusks, swim to a rock or coral, and repeatedly strike the prey against the hard surface to break it open. This is a form of  tool use.

This Wrasse is a long blue and orange fish.
Cuckoo wrasse. Olivier Dugornay, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0&gt;, via Wikimedia Commons.

Megalodon

The largest fish that has ever lived is likely the extinct shark Megalodon, estimated to have reached lengths of up to 70 feet and weighing 50-70 tons. The Megalodon was a giant shark believed to have gone extinct 2.6 million years ago, just in time for the appearance of our ancestors Australopithecus and Homo Habilis. They made a horror movie about a Megalodon that survived until modern times. It is called “The Meg”.

Megalodon shark with its mouth wide open pursuing two whales much smaller than it.
Artistic impression of a megalodon pursuing two Eobalaenoptera whales. Karen Carr, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.

Surströmming (Fermented Baltic Herring) a North Swedish Delicatessen

In 1987 I was selected by my University, Uppsala University in Sweden, to be part of a university level exchange student program. The exchange program was between Uppsala University and Case Western Reserve University in Cleveland, Ohio. In total we were six Swedes (two from Uppsala). I was studying Engineering Physics in Sweden. In the US, I would continue studying Electrical Engineering because the Swedish Engineering Physics program was very similar to the Electrical Engineering program at CWRU. One day we invited the other students to a Surströmming party. When we opened the cans, the American students headed for the windows and opened them. I should say there were other things to eat.

The fermented herring Surströmming from Sweden is often considered as one of the most unappetizing foods in the world. Just ask Google AI or ChatGPT this question, “what is the most unappetizing food in the world”, and you’ll see. The three top unappetizing food according to ChatGPT are Hákarl (Fermented Greenland Shark) – Iceland, Surströmming (Fermented Baltic Herring) – Sweden, and Casu Marzu (Maggot Cheese) – Sardinia.

I grew up with this food, and I don’t think it is unappetizing. It might not be beef bourguignon or trout almondine, but it isn’t bad. The problem is that the smell of Surströmming is not very pleasant and it is strong. However, it tastes quite different from the smell. It tastes like pickled herring with the addition of something sour like lemon. The taste is much better than the smell, which is why you should open the cans outside and then bring them in once the smell has settled. We did not do that because our party was partially a prank. Well, if you don’t like pickled herring, then you won’t like this either.

Ten Amazing Fish Facts
Four Swedes inviting Americans to a fermented herring party. Fermented herring is a north Swedish specialty. Unfortunately, all the Americans experienced a culture shock from the fermented herring. I am the guy smelling the fermented herring can.
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