Antarctic Flora
 
Antarctic endoliths are extremophile life forms.

They have adapted to the most severe conditions no other life can handle.

Less than 2% of the Antarctic continent is free of ice, yet life still exists.   Fungi, algae, lichens, mosses and liverworts manage to survive.   Even in ice core drillings numerous varieties of fungi and extremophile microbes are being discovered.

Cryptoendoliths are a combination of fungi and algae.   They are a type of lichen that grow inside clear rock just a few millimeters under the surface.   If enough light can penetrate through for the cryptoendolith to use, it does so by exploiting photons for reproducing.   These extremophiles are able to shut down metabolically, surviving long periods, even hundreds of years of intense cold, and drought, then creating a colored sheen inside the rock.  

Lichens are found throughout the Antarctic, even in the remote interior.   Their ability to adapt to the most extreme climate - photosynthesizing at temperatures far below freezing - they are seen in exposed rock surfaces near the South Pole.

Algae are not one organism but a variety of many unrelated species.   Most algae contain chlorophyll-a, and some have other pigments.   Snow algae has adapted to growing in permanent snow or ice.   This alga blooms in the summer months, coloring whole snow banks red or orange or green or gray.

A different type of alga, terrestrial green algae, is often mistaken for green moss.   Able to thrive in salty coastal areas, large patches grow in the nutrient-rich areas around Antarctic penguin colonies.   Prasiola crispa is a species of terrestrial alga that looks like sea lettuce.

In places where melt water flushes from glaciers, moss can establish a presence.   Moss has threadlike root structures called rhizoids that anchor the plant to the surface.   A short stem rises from the rhizoids and from these stems tiny leaves containing chlorophyll grow into a spiral pattern.   Mosses grow around melt lakes and streams, and small moss patches inhabit cracks in rocks covered by melt water.

Because of the need for melted water, moss is found mostly on the Antarctic Peninsula.   There are over 100 species recorded, with moss lawns spreading across larger and larger areas as the climate becomes milder in the northern peninsula islands.   In these lawns miniature communities of tiny invertebrates such as protozoans, tardigrades, nematodes and rotifers make their homes.

Liverworts have always been among the first plants to grow on land.   Similar in structure to moss, they have the added quality of adapting to dryer conditions.   In the Antarctic, liverworts have developed unique characteristics that enable them to survive both drying and freezing.   There are 30 species catalogued.

The Cierva Point peninsula on the Danco Coast has extensive areas that support liverworts and the only two higher forms of leaf plants found in the Antarctic.   Both leaf plants are very small and both are restricted to the west and north of the peninsula, and to the islands off the coast where the climate is comparatively milder.   The flowering Antarctic hair grass, and the small ‘cushion’ plant called the Antarctic pearlwort, are both able to survive due to a uniform coverage of flavanoids that help protect the plants from UV-B type radiation.   Botanists and geneticists are studying the plants, to see how the genetic and cellular information they hold can help species develop such immunity in other parts of the planet.

Hair grass often grows near well-developed continuous banks of moss turf.   Green Island and Lynch Island are two protected areas that have banks of moss over a meter deep.

  
Antarctic hairgrass.


The sub-Antarctic islands are different to the islands close to the peninsula in that they have a much greater diversity of species.   Cool temperate islands have small shrubs and trees that are able to grow.

The sub-Antarctic and cool temperate islands have high levels of endemism because of their long-standing geographical and ecological isolation.   Macquarie Island is a relatively young, isolated island.   It emerged above the sea some 600,000 years ago, and has never been in contact with any other land mass.   Its extensive flora includes 41 species of flowering plants.

The New Zealand southern islands have 250 different plant species, including 35 species endemic to the region.   Several species are endemic to a single island group.

With human activity causing a greater displacement of plant species, glacial recession in the peninsula and islands is also creating opportunities for new colonization.   On the peninsula the growing summer warming has increased the size and number of both Antarctic pearlwort and hair grass.   There is a significant increase in the number of leaves, and total leaf area as temperatures rise.

Scientific study is showing that as the southern ocean island climates are warming, great environmental swapping is taking place between invasive and indigenous species.




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Photograph top of page: Cryptoendoliths - NASA NAI Image