The Earth Story

Fossilized organism from Antarctica and South Africa from the Triassic is suggested to be the oldest example of an organism hibernating through the winter.

Travel along with National Geographic photographer Michaela Skovranova as she explores Antarctica in this video short

The Bloodless Icefish

The bloodless icefish (also known as the crocodile icefish) resides in the cold Antarctic waters, where temperatures rarely exceed 2ºC in summer months, and can be as low as -1.8ºC in winter.

Their name describes exactly what is unique about them: they technically do not have blood. Blood is defined as: the fluid that circulates in the principal vascular system of vertebrates, consisting of plasma in which the red blood cells, white blood cells, and platelets are suspended. Though they do have a circulatory system, it lacks all typical cells and platelets, and instead uses a system of proteins. Because of this lack of blood cells, the bloodless icefish's blood is not red, but is instead a foggy white colour (see link to photo below).

This adaption likely arose millions of years ago, when the Antarctic waters became isolated and cooled down to today's temperatures. Regular blood is not suitable for these temperatures and will thicken until the individual dies. The icefish adapted to the conditions by evolving multiple alternative methods for transporting oxygen through the body. One adaption was the loss of scales to diffuse oxygen through their thin skin. They also have massive hearts, enlarged gills, and their own antifreeze. The icefish's adaptions take advantage of the higher-than-average dissolved oxygen that occurs in cold water (see Henry's Law).

But because the icefish rely on the cold, oxygen-rich, isolated Antarctic water to survive, they may be more susceptible to climate/habitat change. Events such as the collapse of major ice sheet from increasing CO2, or a major increase in water temperature (which would reduce the available dissolved oxygen - see Henry's Law) could pressure them to either adapt quickly, or perish.

For a picture of their white blood and heart:http://bit.ly/1GE2RG8

~Rosie

Image and reference: http://bit.ly/1DVY2Ym

Henry's Law: http://bit.ly/1HkQE8e[_

_](https://www.facebook.com/TheEarthStory/photos/a.352867368107647/861639833897062/?type=3&theater#)

Original caption:

South Georgia and the South Sandwich Islands. 

Solstice

About 12 hours ago we passed the solstice, the start of Winter for the Northern Hemisphere and Summer in the Southern Hemisphere. I’d have had this post done but my computer was misbehaving.

Anyway, one of my favorite things to check out on the solstice is the view from the Japanese Himawari-8 weather satellite. That satellite, launched a few years ago, sends back HD pictures and video from a geostationary orbit over the Pacific. That means it can watch as the earth rotates into shadow each night. Here’s its lovely solstice view from today – a thin band of light is always present at the south pole, and the north pole never appears.

-JBB

Video credit: https://twitter.com/himawari8bot/status/943853755753263104

Penguins at Beagle Channel, Tierra Del Fuego, Southern tip of South America

Lowest amount of sea ice ever seen by humans during October/November

This week, this remarkable plot began blowing up on social media. The plot tracks global sea ice abundance – a combined measurement of the area covered by ice in both the Arctic and Antarctic. The red line, 2016, shows that Sea Ice extents globally are by far the lowest humans have ever recorded.

Normally at this time of year, Arctic Sea ice is beginning to recover from low volumes reached during the summer, while Antarctic Sea ice is beginning to contract as sunlight falls on that continent. On top of this yearly variation there have been several long-term trends imposed. Most notably, sea ice extents have been decreasing in the Arctic quite regularly for the last 30+ years – the time humans have been actively monitoring sea ice.

The lowest ever extent of sea ice was reached at the end of summer 2012, but that doesn’t mean the sea ice has been recovering – instead, years since then have seen record low sea ice values “for specific months”. In other words, the long-term trend is gradually decreasing sea ice due to climate change, and records at any time of the year are being broken when a perfect weather pattern hits. One of those weather patterns is hitting in the Arctic right now.

The North Pole right now is already shadowed for the winter. Usually this darkness is associated with plummeting temperatures since no heat from the sun can warm it, but for the past month there have been several times when North Pole temperatures have spiked above the freezing point of water; as much as 15°C above normal for this time of year. These temperatures are being driven by surges of warm air traveling up to the poles from lower latitudes.

Although this effect isn’t fully understood yet, warm winter arctic weather combined with surges of colder air traveling south has been a feature of the last several northern hemisphere winters. It has been proposed that these surges are associated with weakening of the jet streams as climate warms – weaken the jet streams, the boundaries between different convection cells in the atmosphere, and it becomes easier for warm air to be pushed all the way up to the poles. So far this fall Siberia has been anomalously cold while the North Pole has been anomalously warm, consistent with this mechanism.

This warm air preventing ice growth also is combining with the low summer sea ice extent. Sea ice is bright and open water is dark, so when sea ice melts the water beneath will store more heat during the summer. 2016 had the 2nd lowest summer sea ice extent observed in the Arctic, so the Arctic Ocean waters are also warmer now than was typical before humans increased greenhouse gas concentrations in the atmosphere.

Meanwhile, the real puzzle this year is the Antarctic. Sea ice in Antarctic has actually been increasing the last few years – a reminder that the Antarctic is a fundamentally different area than the Arctic. In the Antarctic, the presence of the ozone hole has driven more intense winds that have cooled surface waters and helped the formation of Antarctic sea ice. Furthermore, melting on the Antarctic continent has created a supply of fresh water heading into the oceans and fresh water freezes at higher temperature than salty water. Recent work has suggested this could only be a temporary situation – healing of the ozone hole (actually good!) could remove one of the factors protecting Antarctic Sea Ice, and another major factor could be extra warm water at depth. Several recent studies have suggested that Antarctic Sea Ice could be particularly vulnerable to extra warmth in the subsurface – add a bit of extra heat and that ice retreats rapidly.

Right now, there is likely less sea ice on Earth at this time of year than there has been in about a hundred thousand years – going back to before the last cycle of glacial advance. The downward trend, particularly in the Arctic, is extremely likely to continue in future years. It won’t always produce an all-time low in September - that takes the perfect weather conditions at the perfect time of year – but when the right weather conditions do show up we’ll get record lows for that time of year. Whether this year’s rapid sea ice melting in Antarctica will be a one-time event is, as of now, an extremely important question with no good answer.

Sea ice in these areas represents a habitat for many organisms – a stable place where they can rest before heading out into the ocean. As sea ice extents fluctuate, these species are put under increasing threat. Furthermore, the more open ocean there is, the more heat the oceans can take up – so these drops in sea ice can contribute to warming the surrounding oceans and thus put continental ice sheets under even greater stress. Some scientists have been debating whether it is good communication to place all the Earth's sea ice on one chart when both poles are two distinct systems, but the threat to wildlife globally and the effect of warming oceans may represent reasonable worries based on this plot alone.

-JBB

Data credit: NSIDC http://bit.ly/2frYJyk http://bit.ly/1jOd0VZ Read more: http://n.pr/2eBPFLv http://scienceblogs.com/stoat/2016/11/18/sea-ice-wossup/ http://cnn.it/2eRzeKH http://bit.ly/2gnschY

Victory!

Earlier this year, I wrote about the Ross Sea ecosystem off the coast of Antarctica, and how it is in trouble due to unregulated overfishing of the Antarctic Toothfish (see that previous post here: http://bit.ly/2ffTp5F). I am happy to report that, as of Friday, it is set to become the world’s largest marine protected area. 24 countries unanimously agreed to the proposal after two weeks of discussion, and it means that fishing will no longer be allowed within the 1.1m sq km reserve as of December 1, 2017. That’s an area the size of France and Spain combined, or almost twice the size of Texas.

This is amazing news! In my previous post, I explained that the Ross Sea ecosystem is one of the last untouched ocean wilderness’ on Earth. Its nutrient-rich waters are some of the most productive in the Antarctic. Huge blooms of plankton and krill support vast numbers of species, from icefish and crabeater seals, to Adelie penguins and Minke whales. In fact, it is thought that up to 16,000 species live here in an intricate, interconnected web of life.

The Antarctic Toothfish lay at the centre of this web, and the high demand for its flesh - sold under the false name, Chilean Sea Bass - wrought havoc on the entire ecosystem. The passing of this agreement means that the Ross Sea ecosystem will be able to recover, survive, and thrive for years hereafter. More importantly, it shows that it is indeed possible for the world to cooperate on pressing issues, environmental or otherwise.

VP

References: http://bbc.in/2eJUP6N Image credit: Wikimedia commons (http://bit.ly/2eQQyOR)

This is a Brinicle, a brine icicle, which can form in the waters of both the Arctic and the Antarctic.

The icy phenomenon, also known as the “Icicle of Death”, is caused by cold sinking brine.

In winter, the air temperature above the sea ice can be below -20C, whereas the sea water is only about -1.9C. Heat flows from the warmer sea up to the very cold air, forming new ice. The salt in this newly formed ice is concentrated and pushed into brine channels. As it is very cold and salty, it is denser than the water beneath. As the cold dense brine solution comes in contact with the warmer water below the surface, a brinicle forms.

Brinicles grow fairly rapidly with some studies recording growth of 2 metres in less than 10 hours. In this photo, which was taken in Antarctica’s McMurdo Sound, the ice has reached the sea floor, forming a pillar.

Here is a cool timelapse video of the formation of a brinicle, it’s a must watch! http://www.youtube.com/watch?v=Y3lnNvyFXUs

-Jean

Photo courtesy of: Bill Curtsinger

Oldest air from Antarctic Ice

Ice cores from Antarctica and Greenland have been invaluable in deciphering the history of Earth’s glaciers over the past 800,000 years. When snow is compacted into glacial ice, tiny bits of atmosphere are trapped in the open spaces, and the age of the ice can be found by literally counting the layers created by each year’s snowfall. By sampling cores of ancient ice, scientists have managed to sample the atmosphere as long as 800,000 years ago – the previous record for oldest atmosphere sample from an ice core.

That air gives us a record of CO2 changes in the atmosphere that correlate strongly with temperature changes and the waxing and waning of glaciers – CO2 goes down and the earth enters a 100,000 year ice age, CO2 goes back up and that ice age breaks up.

Prior to 800,000 years ago, we know there were glaciers advancing and retreating, but something different was happening. Instead of glaciers lasting 100,000 years, they lasted only 40,000 years before they collapsed. There are theories for why this happened, mostly focused on CO2 changes, but without a better sample of the atmosphere that’s a difficult hypothesis to support.

This photo shows a team of scientists from Princeton University and the University of Maine on the Antarctic Ice Cap in an area called the Allan Hills. See how the ice is blue? Blue color is a signature of very old ice, ice that has been at high enough pressure that most of the air bubbles have been squeezed out. The Allan Hills are an area where the ice sheet is ablating – older ice is coming up to the surface and melting or sublimating away. Therefore, cores into this ice have the potential to sample ice even older than what we’ve found through other drill cores.

There’s one problem though – when glacial ice is squeezed back up to the surface and ablated, it loses the “annual bands” that let scientists say exactly how old the ice is. The scientists in this study drilled shallow cores into this ice and got samples of the atmosphere, but how to figure out its age?

To do that, they used one thing in the atmosphere that does change gradually over time – the abundance of one isotope of Argon, Argon-40. Argon-40 is a gas that makes up about 1% of the atmosphere and it is produced by radioactive decay of an isotope of Potassium. Potassium is pretty abundant in the earth, so over geologic time the amount of Argon-40 is slowly ticking upwards. By measuring the abundance of Argon-40 in the atmosphere they got from this ice core, they estimated that the air they were sampling was trapped around 1 million years ago with a margin of error of ± 200,000 years. Not nearly as small of error as you get by counting individual bands in an ice core, but enough to say that this ice predates the start of our current cycle of 100,000-year glaciations.

The chemistry of the ice allowed the team to argue that they were able to sample across the boundary between a glacial/interglacial cycle; ice preserves an isotopic record of the temperature when it forms and they see a large shift in temperature during this section of core.

Those temperature shifts are correlated with changes in CO2, just as in the other ice cores, but the absolute numbers are different. The largest ice sheets in the last 800,000 years formed when CO2 levels dropped to about 180-190 ppm; nothing in this ice core got down to below 220 ppm. On top of that, the highest CO2 measured in this core from 1 million years ago was higher than any measured CO2 content between 800,000 and 450,000 years ago.

In other words, when the Earth switched from having ice sheets last 40,000 years to having ice sheets last 100,000 years, atmospheric CO2 was changing too. Once CO2 dropped a bit, ice sheets were able to expand more than they previously could – hinting that the causal link between CO2 drops and longer ice ages might be correct.

Those CO2 changes are small compared to the atmospheric change that has happened in the last century. The difference between 40,000 year and 100,000 year ice ages observed in this core is 30 ppm at the low end and 7 ppm at the high/interglacial end. In the last 200 years, burning of fossil fuels and land use changes have increased atmospheric CO2 to 400 ppm and this core again verifies that it has been well over a million years since Earth’s atmosphere has had this high of concentration of greenhouse gases.

-JBB

Image credit: Mike Waszkiewicz, National Science Foundation http://bit.ly/1E3fLXe Original paper: http://www.pnas.org/content/early/2015/05/06/1420232112.full.pdf

Why do we study the Poles?

Polar Regions are of upmost importance to our planet and are formidable ecosystems with harsh conditions. A large number of scientists globally devote their careers to studying them, but why? Why should we study areas with little human population, or potential for human settlement?

Firstly, Polar Regions act the same way a thermometer acts in a first aid kit, giving us early warning of when climate change is occurring. In our case this early warning is telling us the Poles are warming up. This can be evidenced as in the Arctic sea ice is retreating and glaciers moving faster than before. Meanwhile in the Antarctic ice shelves are breaking up and melting.

Secondly, the Artic and Antarctica act as regulators for climate globally; for example European weather is often affected by cold Arctic winds. Warming will continue to accelerate in the Poles, potentially affecting climate globally, as stated by the Intergovernmental Panel on Climate Change (IPCC) in 2007. This panel has projected the Arctic could be free of ice anywhere between 2050 and 2100 depending on our continued responses as a species.

Finally, the Poles tell us about processes affecting the globe. The Arctic and Antarctica are linked in to natural processes occurring worldwide. One such process is the ocean conveyer belt. The ocean conveyer belt is controlled by currents and circulation and transports vital nutrients for ocean flora and fauna worldwide. Changes in climate at the poles is projected to increase freshwater in the ocean due to melting ice and increases of precipitation. As more freshwater is produced by the melting process they inhibit mixing with lower layers of water, which prevents formation of deep water, thus disrupting the circulation of nutrients. ~SA

Picture: http://bit.ly/1EjElqm By Andrew Mandemaker. Showing Mount Herschel, Antarctica in 2006. Further Reading: http://bit.ly/1GCcp1K and http://bit.ly/1DI0Z9n. Both by the British Antarctic

Local Sea Level Rise- one of the trickiest predictions. Part 1.

In my last post (http://on.fb.me/1advPiu) I mentioned that sea level rise from Antarctica melting would not be distributed equally throughout the globe, and in the coming posts I'll explain why. Currently, most of sea level rise is due to thermal expansion caused by warming of the oceans, the remainder coming from melting ice and reduction of liquid water storage on land.

In the latest IPCC report, it has been suggested that sea level may rise up to a meter by 2100. This prediction is assuming that Antarctic Ice Shelves remain stable, which may not be the case (see our previous post: http://on.fb.me/1yuE5jq). The latest IPCC report has also predicted that it is very likely that over 95% of the world’s ocean surface will rise...but what about the other 5%? Those surfaces are most likely near current and former glaciers and ice sheets. Sea level rise will be experienced very differently in different parts of the world, with deviations up to 50% from the global mean sea level projection.

Antarctica and Greenland hold the vast majority of earths freshwater and are also contributors to sea level rise. A common belief is that melting of these vast ice caps would result in uniform sea level rise. This is not the case – models have shown that such melting can actually cause a decrease in relative sea level around these regions. There are two main reasons behind this; the first one is gravity.

These ice caps (Antarctica especially) are so massive that their gravitational force pulls water towards them, much like the moon does with the ocean. This effect results in sea levels higher than they would be otherwise for thousands of kilometers around them, which means lower sea levels elsewhere. As they shrink, their gravitational pull weakens, which also lessens their hold on the surrounding water which leads to higher sea levels elsewhere.

To put some numbers on this, a researcher from Harvard calculated that if the entire West Antarctic Ice Sheet collapsed and melted, the global mean sea level rise would be up to 5m, however it would be approximately 6.5m in various cities in the USA, and less in other areas. The image depicts findings from a 2012 paper by Sallenger and others, showing the distribution of sea level rise across the United States of America.

-MJA

Image credit: Sallenger et al., 2012.

Further reading/references: IPCC on sea level rise: http://bit.ly/1CrvtOk

http://bit.ly/1CrvtOk

http://bit.ly/1nddrec

Sallenger Jr, A. H., Doran, K. S., &; Howd, P. A. (2012). Hotspot of accelerated sea-level rise on the Atlantic coast of North America. Nature Climate Change, 2(12), 884-888.

NASA explaining why the Arctic and Antarctic sea ice systems work differently.

OZONE DEPLETION AND THE ARCTIC Please see this previous post about the ozone hole over Antarctica and its effect on the countries bordering it (including increased skin cancer rates):http://on.fb.me/SMU6uC To recap somewhat, ozone is a gas made up of three oxygen atoms (O3), which occurs naturally in trace amounts in the stratosphere (the upper atmosphere) and protects life on Earth from the Sun’s ultraviolet (UV) radiation. The stratospheric ozone layer screens all of the most energetic, UV-c, radiation, and most of the UV-b radiation. Ozone only screens about half of the UV-a radiation. Stratospheric ozone is typically measured in Dobson Units (DU), the number of molecules needed to create a layer of pure ozone 0.01 millimetres thick at a temperature of 0 degrees Celsius and an air pressure of 1 atmosphere. Earth’s atmosphere has an average amount of ozone of 300 Dobson Units. Ozone depletion is caused by chemicals called chlorofluorocarbon compounds (CFCs) known as "freons" and bromofluorocarbon compounds known as Halons, which escape into the atmosphere from refrigeration and propellant devices and processes. These chemicals are so stable that they can persist for decades within the lower atmosphere, but in the stratosphere ultraviolet light breaks the chemical bond holding chlorine to the CFC molecule. This destruction of the ozone does not happen immediately; these roaming chlorine molecules become part of two chemicals that are so stable that scientists consider them to be long-term reservoirs for chlorine, under normal atmospheric conditions. The atmospheric conditions over Antarctica during winter are unusual however; there is an endlessly circling whirlpool of stratospheric winds called the polar vortex that isolates the air in the centre. As there is no sunlight in Antarctica over winter, the air in the vortex gets so cold that clouds form and chemical reactions take place which could not take place anywhere else. These reactions can occur only on the surface of polar stratospheric cloud particles, as their frozen crystals provide a surface for the chemical reactions that free chlorine atoms in the Antarctic stratosphere. The inactive chlorine chemicals are converted into more active forms like chlorine gas (Cl2). When sunlight returns to the South Pole, the UV light breaks the bond between the two chlorine atoms which releases free chlorine into the stratosphere. The free chlorine molecules are then responsible for a series of chemical reactions that destroy ozone molecules but return the free chlorine molecule unchanged and free to do more damage (a catalytic reaction). There is also a second catalytic reaction with chlorine that contributes a large fraction of ozone loss, which involves bromine. The ozone hole grows until temperatures warm enough that the polar vortex weakens, enabling air from the surrounding latitudes to mix with the air in the polar vortex. The ozone-destroying forms of chlorine are then dispersed, until the following spring. The Montreal Protocol on Substances that Deplete the Ozone Layer, which was signed in 1987, limited production of ozone-depleting substances. All non-essential products containing CFCs were banned; these included all aerosol products, pressurised dispensers and foam products. All CFC containing air conditioning and refrigeration appliances were also banned in 2001. Hydrofluorocarbons (HFCs) were used to replace chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) for many uses, for example solvents or refrigerating agents. This in turn was partly responsible for the increased concentration of HCFCs in the atmosphere. HFCs were used as they do not pose any harm to the ozone layer, having no chlorine. HCFCs and HFCs are now thought to contribute to anthropogenic climate change, as these compounds are capable of trapping enormous amounts of infrared radiations in the atmosphere. They are thought to be up to 10,000 times more potent greenhouse gases than carbon dioxide on a molecule-for-molecule basis. The Montreal Protocol currently calls for a complete phase-out of HCFCs by 2030, but does not place any restriction on HFCs.  In the first three months of 2011, a large hole appeared in the ozone layer above the Arctic. Every year the Arctic ozone layer had suffered some damage over the winter period but the effect was normally short-lived, as there are generally warmer stratospheric conditions over the Arctic than over the Antarctic. The Arctic polar vortex is also about 40 percent smaller than a typical Antarctic vortex, but is more mobile. In 2011, between 18 and 20 kilometres above the ground, over 80 per cent of the existing ozone was destroyed. The ozone loss in 2011 over the Arctic was twice the levels seen in 1996 and 2011, previously the highest records. The hole was similar in size to the holes seen over Antarctica in the 1980’s. Please read the previous post for more information on the Antarctic ozone hole (http://on.fb.me/SMU6uC). Though the Arctic ozone hole would have allowed in more UV radiation than before, it is unlikely this would have added much risk to the underlying population's risk of UV-related cancer.  Scientists are now examining why the hole over the Arctic grew so large. It is possible this occurred because the stratosphere remained cold for several months longer than usual. This cold air then allowed water vapour and nitric acid to condense into polar stratospheric clouds, which as explained above, allow chlorine to convert into chemically active forms. It is unknown why the stratosphere remained cold for so long, though climate change could be responsible. Global warming occurs only at the bottom of the atmosphere and warms the surface but cools the stratosphere. The Intergovernmental Panel on Climate Change (IPCC) concluded in 2007 that there has been global stratospheric cooling since 1979, but it is not yet clear whether this is a result of climate change.  Without the 1987 Montreal Protocol however, chlorine levels would be so high that an Arctic ozone hole would form every spring. The ozone-depleting chemicals that are already in the atmosphere mean that the ozone hole over Antarctica and possible future Arctic ozone loss will continue for decades. If an ozone-depletion area over the Arctic forms which is similar in size to the one over the South Pole, over 700+ million people, wildlife and plants could be exposed to dangerous UV ray levels. You can watch a video showing Arctic ozone loss 2010-2011 here:http://www.youtube.com/watch?v=aNNRjbBK1Ns. The maps used of ozone concentrations over the Arctic come from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite. The left image shows January 1 to March 23, 2010, and the right shows the same dates in 2011. March 2010 had relatively high ozone, while March 2011 has low levels. The image consists of maps of ozone concentrations over the Arctic from the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite. The left image shows March 19, 2010, and the right shows the same date in 2011. March 2010 had relatively high ozone (the red colour denotes high DU), while March 2011 has low levels (blue and purple show low DU). -TEL Arctic ozone hole: http://www.nature.com/nature/journal/v478/n7370/full/nature10556.html; http://www.newscientist.com/article/dn20988-arctic-ozone-hole-breaks-all-records.html; http://www.theozonehole.com/arcticozone.htm; http://www.theozonehole.com/nasaarctic.htm; http://earthobservatory.nasa.gov/IOTD/view.php?id=49874 http://ozonewatch.gsfc.nasa.gov/facts/hole.html More on ozone layer protection: http://www.epa.gov/ozone/strathome.html You can read the Montreal Protocol here: http://ozone.unep.org/pdfs/Montreal-Protocol2000.pdf Image: Rob Simmon, with data courtesy of Ozone Hole Watch.

Meet the yeti crab, a creature so unusual that a whole new biological family had to be created to classify it. It was found along the Pacific-Antarctic Ridge, 1,500 kilometres south of Easter Island at a depth of 2,200 metres living on hydrothermal vents. As a result of analysis based on morphology and molecular data, the organism was deemed to form a new biological family (Kiwaidae). But, a lot else remains an enigma and much more is to be discovered. We do know that yeti crabs lack pigmentation in the eye and are hence thought to be blind. Also of interest, their fluffy pincers have been discovered to contain filamentous bacteria which may be involved in a chemosynthetic relationship with the organism. It is suggested that these bacteria may detoxify some of the poisonous minerals emanating from the hydrothermal vents. -Jean Photograph by Ifremer A. Fifis