Antarctica & Climate Change, What Would A Greened Antarctica Look Like? – Plants Of Prehistoric Antarctica, Meyer Desert Formation Biota, & Speculation On The Future

November 24, 2016 in Geology & Climate, Plants

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Antarctica is an alien world in some ways. While many of the animals that visit its shores, or live on them, are recognizable, as are the plants, lichens, and algae there as well, the sheer intemperate quality of the place leads to blunt rearrangement of “ordinary” circumstance — with the place seeming familiar in many ways, but with a sense of strangeness and chance to it that isn’t found in many other parts of the world at this point.

A place where it’s too cold and dry for much to grow other than organisms that could possibly do well even if they were left on a literally alien world — extremophile microbes, various though types of lichen, fungi, pink algae, etc.

The continent hasn’t always been this way though. Even as recently as 3-4 million years ago there were patches of forest remaining in isolated areas, before eventually being subsumed completely by the ice sheets. Leaving the desert-like place that the interior of Antarctica now is.

Anthropogenic climate change will be changing this over the coming centuries and millennia though, though to what degree is up for debate — with the melting of West Antarctica seemingly being inevitable at this point, and the melting of large tracts (or all) of East Antarctica seemingly now a real possibility.

Presuming a ‘business as usual’ path is followed, as far as cumulative emissions go, to the close of the century, it should take an estimated ~400,000 years for all of the carbon dioxide that will be released into the atmosphere as a result of industrial human activity to be removed, and for the weather and climate to settle back into their own patterns. (This estimate incorporates what’s known about various feedback loops, such as permafrost melting and methane release, as well as the way the carbon cycle has responded in prehistory to various associated factors.)

With those changes, Antarctica stands to once again become a place where the sorts of obvious life forms that now inhabit the temperate parts of the globe can maintain a presence.

The continent will still in many ways be a strange one, owing to its position right around the South Pole. The “Summer” and “Winter” for instance will seem perhaps more like one giant day and night that lasts a year, when near the exact pole, rather than a world of regular brief periodicity, as experienced at the equator.

So what sorts of plants and animals will live there following these changes? Perhaps similar ones to those that persisted there as part of the Meyer Desert Formation biota until 3 to 4 million years ago?

Or perhaps the remainder of the Antarctic Flora that still persists (somewhat) in scattered form throughout southern South America, southernmost Africa, New Zealand, Australia, and New Caledonia, will make a return? Despite the change in Antarctica’s location (and light exposure) since then? Will people play an active part in this?

Tree ferns South Island New Zealand

Given that people will (very?) likely play a hand in the greening of Antarctica, with regard to what species of plants and animals are introduced, and the fact that people have their own motives on that count, the future floral and faunal residents of the continent may well be quite different than those that lived there in the past. Crows, rats, rabbits, and squirrels, are all probably pretty likely to find residence there at some point, but what about cattle (or descendants there of?), musk ox, foxes, wolves/dogs, coyote, deer or elk (wapiti), bears, etc?

If the continent was to eventually provide for a notable human population it seems likely that some form of animal husbandry, and associated cold weather grain and/or hay summer agriculture would be required. Reliance solely on fish and sea mammals wouldn’t likely be enough to sustain a very large population, especially as the ongoing overfishing and acidification of the oceans is likely leading to the “desertification” of vast swaths of it. And for that matter, during the end-Permian mass extinction the equatorial waters apparently got so hot that not many animals could live there.

Thats all speculation though, more generally I propose here to highlight some of the species that are related to those that have lived in Antarctica during warmer periods, and also those that may not have lived there before, but seem likely to be well suited to doing so.

Such plants would be a potential choice for those looking to ‘help’ the greening of the continent. Though the help wouldn’t be immediate, as even after the ice sheets are gone, and temperatures have risen substantially, and regular mass flooding has ceased, soil (substrate) would have to accumulate or be built up — as large ice sheets scour down to the bedrock, there will be practically nothing there in most places, (under the ice sheets).

Current Plant Life Of Antarctica

As far as plants go, Antarctica is currently host to only around 100 species of mosses, 25 species of liverworts, 250 ‘types’ of lichens, and only 3 flowering plants — all 3 are found on the Antarctic Peninsula — Antarctic hair grass (Deschampsia antarctica), Antarctic pearlwort (Colobanthus quitensis), and the introduced annual bluegrass (Poa annua). So, bryophytes mostly. In addition, though, there are around 700 known species of algae (whether terrestrial or aquatic) living on the continent. Biological soil crusts are also present.

Growth of these plants occurs mostly only during a short period during the summer — when they initiate rapid growth, and flower and go to seed in a much shorter period of time than relatives in more temperature regions do. Notably, peak metabolic rate is at a much lower temperature.

Getting a bit further away from the pole, though, on the surrounding islands of Antarctica, a greater variety of plant life is found. Notably, introduced rabbits proliferated rapidly on some islands (in boom and bust cycles) and have already, and also likely will, lead to the extinction of some species and/or subspecies.

Antarctica Kerguelen Cabbage plants

As noted near the start of the article, Antarctica used to be much greener though — all the way from when it broke off from Gondwana (~110 million years ago), to when it separated from South America (30 to 35 million years ago), to until only a few million years ago, it supported trees, animals of various types, and a much greater overall diversity of vegetation.

The big kill, which wasn’t ‘total’ until just a few million years ago, was primarily the result of the Antarctic Circumpolar Current forming following the final separation of West Antarctica and South America. Much of the flora that used to live on Antarctica though is related to some of that which survives in the southern parts of South America, Oceania (New Zealand’s South Island in particular), and South Africa.

Cushion plant mountains

Meyer Desert Formation Biota

The Meyer Desert Formation biota was previously found in the Dominion Range of the Transantarctic Mountains in Antarctica — near the Beardmore Glacier. Research and fossil evidence has shown that intermittent warm periods allowed various plants to survive in it until as recently as 3 to 4 million years ago — this includes: the Antarctic Beech (Nothofagus beardmorensis), various types of mosses, a ranunculus of some type, flowering cushion plants, mare’s tails (Plantaginaceae), sedges (Cyperaceae), and at least 3 varieties of liverworts.

Some animals managed to survive there until recently as well, including: small freshwater clams (Pisidium), a freshwater air-breathing snail (lymnaeid), a fly (cyclorraphid), and at least 2 types of weevils (curculionid beetles).

Beech trees Antarctica

The “Antarctic Flora” — Distinct Community Of Vascular Plants That Had Origin On Gondwana

The term “Antarctic flora” refers to a very distinct grouping of vascular plants that evolved a long time ago on the supercontinent of Gondwana — specifically on the parts that now compose southern South America, New Zealand, southern Australia, southern South Africa, and New Caledonia, which previously had been adjacent to one another.

Of these regions today, South Island, New Zealand, because of its long isolation is thought to have the floral environments most similar to those of greened Antarctica.

This Antarctic flora consists of conifers in the families Podocarpaceae, Araucariaceae and the subfamily of Cupressaceae dubbed Callitroideae; of various ferns and flowering plants (cushion plants, various ranunculus); various angiosperms (Proteaceae, Griseliniaceae, Cunoniaceae, Atherospermataceae, and Winteraceae) including the southern beeches (Nothofagus) and fuchsia (Fuchsia). This Antarctic flora notably includes the tree fern (Dicksonia) of parts of Australia.

(I’ve had to split the article in two so that it wouldn’t crash, the half relating to the plants and animals likely to colonize Antarctica, or to do well if brought if there, can be found here: Climate Change & Antarctica, The Future Return Of Antarctic Flora & New Arrivals, Part 2).

Unfurling frond tree fern

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