At the ends of the world, the sun's reach is weak. Life struggles or is entirely absent. And indeed what life could survive in a world of freezing temperatures for most, or all of the year. A treeless world of hardy shrubs, lichen and moss dominates the north while a permanent layer of ice covers the south. These are the last of the biomes of our planet.
This is the Arctic and Antarctic. This is the tundra and ice. Poles of our world receive sunlight at only an oblique angle, bringing very little in the way of heat, and for almost half the year there is no sun at all. This dynamic of poor solar heating produces the coldest of all the biomes, the tundra and ice. What separates these two biomes is only 10 degrees of Celsius.
In the tundra, summer temperatures rarely exceed 10 degrees Celsius. This prevents the growth of trees, and so marks the boundary between boreal forest or taiga. and the tundra.
Only hardy shrubs, herbs, moss and lichen can grow here, covering the bleak landscape when it's not already covered in ice as it is for most of the year. These lands fringe the entirety of the Arctic Ocean, from North America and the coasts of Greenland to the north of Russia. The ice biome permanently covers ground that never sees temperatures rise above zero degrees Celsius. Which makes sense when you consider that this is the point at which liquid water freezes.
That liquid is essential to life, and so, in a permanent state of frost, no plant life would have been possible even if the ground wasn't covered in a kilometres deep layer of solid ice. The overlap of these two biomes with their respective climate zones of the same names is pretty much total, and so those climate zones are not misnomers. Because of this, I have covered both zones in detail in my Secrets of World Climate series in two episodes.
and you'll find these linked top right and also in the description. For a full treatment of this subject, please watch these in conjunction with this video as, unlike in real life, I'm not going to repeat myself here. In our Haldrige Lifesones chart, we find the tundra and ice in the top two rows.
It is worth noting that the term desert is used, which is technically accurate since the ice is deserted of life. Note also that the cooling of the temperate scale is not just in terms of increasing latitude, but also in altitude, and so tundra and ice are found in the high places of the world, above the treeline in the Rockies, Andes, Alps and Himalayas. However, in terms of percentage of land area covered, these areas are tiny in comparison to the Arctic and Antarctic regions. The permafrost, a permanently frozen layer of soil and ice stretching up to a kilometre down, is present in all Arctic tundra, as it is in the Taiga.
And like in that other biome, leads to extensive bogs and lakes, since liquid water cannot drain into the rocks below. The permafrost is all but absent in alpine tundra, and in the small tundra-like areas and islands found around the Southern Ocean, such as Tierra del Fuego, the Falklands, the South Sandwich Islands and so on. Beneath the permanent ice cap, no life exists.
But in the tundra, life does, albeit in a limited form. In the short tundra summer, there are only about 50-60 growing days permitted. This is too short for tree species to germinate, and so this realm is dominated by plants that can quickly flower and reproduce in such a short window.
Lichen, a mix of fungi and algae, is the hardiest of all plant classes globally, and is found in all parts of the tundra. Musses are the next most hardy plant class, and these simple and ancient plants are also found throughout the biome. Sedges and cotton grass can be found in the often boggy, peaty conditions existing in the tundra plains, while on slightly elevated sites, low willows, other grasses and rushes can be found.
The tallest tundra species are found on better-drained, sandy soils of riverbanks, and come from species families that include willow, sunflower and legume. Isolated stands of coniferous trees, known as forest tundra, can be found in certain areas. These are in fact vestigial remnants of taiga from earlier times when the climate was once warmer, and have survived as clonal colonies unable to reproduce through the normal channel of seed germination.
Fungi and bacteria are found throughout the soil and act as essential vectors in the breakdown and recycling of dead plant material. The fauna in the tundra is limited, but where it exists is well known. Polar bears patrol the coasts, while inland areas feature large herds of grazing giants such as reindeer, caribou, musk ox, and their accompanying predators, arctic wolves. As in the tiger, these species are larger than normal, since a bigger body is easier to keep warm than a small one.
But not all tundra mammals are large, and arctic hares, foxes and lemmings are also common, with many sporting seasonal white coats as camouflage during the long icy winters. Antarctic fauna is also well known in the form of enormous colonies of penguins, as well as the seals that prey upon them. But strictly speaking, these animals are not part of the tundra or ice biome as such, since they rely entirely upon the ocean instead of the land for their survival.
In terms of threats, the tundra and ice are not directly threatened by human activity, since so few people live in these regions, less than several hundred thousand in a planet of billions. However, with the advent of climate change, whether man-made or natural, the permafrost of the tundra is melting, as are the ice caps of Greenland and Antarctica. The melting of the permafrost leads to the release of methane, a potent greenhouse gas, while the melting of the ice caps will lead to sea levels rising and global consequences. The tundra and ice make up the last two biomes in the Lonzo 8 classification system, and while other specialised biomes exist such as in the subtropical highlands around the equator, or the wetlands found across the globe, this will all I'll be covering for now in this series.
We have travelled from the equator to the poles. Exploring the amazing living landscapes across our varied planet. The greatest biodiversity of all within the broadleaf forests of the tropics. The intense heat of the tropical savannahs and the great herds and their predators.
The desolation of the hot and cold deserts that byland area make up the largest of the biomes. The unique and often forgotten shrublands of the subtropics and the Mediterranean areas. The endless grasslands of the temperate regions. and their geographic neighbours, the beautiful mixed forests of North America, Europe and Eastern Asia, the dark and forbidding expanse of the Taiga, the wasteland of the tundra and ice at the top and bottom of our world. It's been an epic journey and I hope you've learned or experienced something from it.
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You'll find a link in the description. I'll see you all next time for the start of a brand new series. Look out for the notification of the premiere a few weeks from now.
Until then, stay green.