Plants Of East Antarctica

A unique biodiversity surviving since billions of years but discovered just recently c. 60 years ago. These plants are under treat with various human perturbations.
East Antarctica is a unique and fragile ecosystem with very low species diversity for both plant and animal kingdom. No higher life forms exist, however, lower forms of plants and invertebrate organisms are believed to be surviving there since millions of years. However, they are under constant threat from external influences.
Contents

Algae
Lichens
Mosses
Discussion and conclusion
Table 1. Flora of east Antarctica.
REFERENCES


East Antarctica is a unique and fragile ecosystem with very low species diversity for both plant and animal kingdom. No higher life forms exist, however, lower forms of plants and invertebrate organisms are believed to be surviving there since millions of years (Bormann et al. 1995). The reason for limiting life in Antarctic ecosystem is the climate, which is normally sub-zero temperatures with severe katabatic winds, snow drift, blizzards, extremely low humidity, snowfall, low availability of liquid water and poor sun light even during summer months, high doses of UV radiation etc (Gajananda 2003). In contrast to this extreme conditions, some life forms existed since million of years in the soils, streams, lakes, rocks, glacial lake ices, and melted water pools etc. Several species of algae, lichen and mosses are found in east Antarctica. The soils are arid, saline and lacking in organic matter (Gajananda 2007).
Amongst the algal species, cynobacteria Phormidium frigidum and Lyngbya martusiana dominated. Green algae were rare. About 400 taxa of lichens, 75 spp of mosses, 75 spp of fungi, 2 species of liverworts and 2 higher plants are reported from Antarctica (Ahmadjian 1967) (Table 1). However, till today knowledge of taxonomy and distribution of the bryophytes of Antarctica is still incomplete (Okitsu et al. 2003, 2004).

Algae

The algal species of east Antarctica occupied distinct levels of habitats; (a) on damp soils (b) in association with mosses and (c) on quartz rocks in the water pools. The sunlight-exposed rocks near the lake banks, favored growth of blue-green encrustation. The algal crusts composed of both N2 and non-N2-fixing species. The cyanobacterial patches covered with mucilage were abundant on the soil surface near the edge of the stream and depressions and under rocks and stones. Algae are rarely found on glacier.
Algae are found mostly on the surface of the rocks, boulders and weathered soils. Sometimes, they are also found under rocks (cryptoendolithic), particularly light-colored quartz stones, where the microclimate is more favorable than in the surrounding sand or soil. The species richness of algae was highest in the embankment of the streams. Some species such as Oscillatoria, Chroococcus species are dominant in east Antarctic lake banks. Non-N2-fixing species Phormidium frigidum also constitutes an important and dominant role. Majority of the algae recorded have possessed tough and collared mucilage. The answers to these are (a) light filtration and (b) increasing water retention capacity (Gajananda et al. 2004).
Photographs of algal mat inside the frozen lake of east Antarctica 

Lichens

Lichens occupied hilly and rocky terrain of east Antarctica and the most widespread floras. Lichens such asRhizocarpon flavum, Acarospora gwynnii, Xanthoria elegans, Buellia pallida, Lecidia cancariformis, Polycauliona murrayi, Umbilicaria spp dominated east Antarctic ecosystem. Lichens are found growing on nutrients low porous rock surfaces. The porous rocks retain little amount of water and become warmer under sunlight than the soils making favorable habitat for lichens to grow. They are present mainly in the water free rocky areas (Gajananda et al. 2004). Lichens population is high in the humid areas of east Antarctica. They are cosmopolitan and are the initial colonizers of bare rocks starting the ecosystem succession process. As the first colonizer of the rocky areas they paved the way for other forms of life to gradually adapt in this harsh environment.

Photographs of porous rocks (weathering) over east Antarctica 

Photographs of crutose Lichens on rocks, paving the path of ecological
succession over east Antarctica 

Mosses
The dominant species of moss is Bryum argenteum in east Antarctica. They are capable of photosynthesis in low light intensities and low temperature. Bryum argenteum is the dominant flora of east Antarctica in terms of density and population. They are also found in association with algae such as Nostoc spp. Moss turfs are seen near the ice-melt water streams from the glaciers. They tend to grow more on places with finer sand than the coarse sand with pebbles. The moss habitat forms the substratum for the micro invertebrates such as tardigrades, nematodes and rotifers.
Photographs of soft and delicate mosses carpet of east Antarctica

 Photographs of dark brown mosses on rocks over east Antarctica

Discussion and conclusion
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Chloromonas subroleosa belonging to chlorophyta giving red color to the snow are thought to attributed the development of pigment in the species (Ling and Seppelt 1993). Rare occurrence of green algae and dominance of blue green algae in east Antarctica suggests that the cyanobacterial species are better adapted to the harsh climatic conditions of east Antarctica (Broady 1996). The prokaryotic cell wall structure ofcyanobacteria consisting of diaminopimelic acid and muramic acid provides better resistance to the cells (Resch and Gibson 1983). The green algae are not efficient in tolerating the freeze-thaw condition of east Antarctica. Bidigare et al. (1993) mentioned that samples of red and green Chlamydomonas (Chlorophyta) when exposed to freeze-thaw conditions, resulted in lysis of the green cells whereas the red cells survived due to increased membrane fluidity. The high doses of UV-B radiation in east Antarctica resulted in strong photo-oxidation of chlorophyll-a of green algae causing damage to the algal cells whereas other pigments are more protective against UV (Buedel et al. 1997; Quesada and Vincent 1997; Hoham and Duval 2001). Hence, the algal species of east Antarctica are dominated by cyanobacteria.
Lichens populations are high in east Antarctica due to their highly adaptive capability, favoring mostly humid environment. They are found to have photosynthetic optimum at low light intensities and very low temperatures of 0-5o C (Lange and Kappen 1972). The high adaptive features of lichens for nutrient absorption by heterotrophic fungi and photosynthesis by algal partner, they are commonly regarded as the pioneer species, reported for starting autotrophic succession on bare rocks (Stoutjesdijk and Barkman 1992). Lichens have the strategies to absorb nutrients by releasing some weak acids, resulting in the dissolution of some nutrients from the rocks (Stoutjesdijk and Barkman, 1992; Upreti and Pant, 1995). Some rock-inhabiting cyanobacterial lichens produce ultraviolet absorbing scytonemin and mycosporine-like amino acid derivatives, which protect them from harmful UV light (Buedel et al. 1997).
The photosynthetic capability of Bryum argenteum can start within a few hours of thawing after a prolonged period of freezing and almost immediately following short snowfall periods (Strebel et al. 1998). Amongst the most widespread species found in the east Antarctica Bryum argenteum is also one of them. The remarkable strategies to tolerate very cold temperature and dry conditions make them abundantly found in east Antarctica (Gajananda et al. 2004).
Finally, the poor species diversity of east Antarctica, which had tolerated the harsh natural conditions of Antarctica, is becoming vulnerable, today, to many external influences. Amongst these are the negative anthropogenic impacts, climate changes, ozone holes and most importantly the melting of glaciers. Collections for scientific studies are also becoming a threat to these endemic floral species of east Antarctica. As the population diversity of the species are poor and also less studied for any medicinal or herbal values, it is likely that they may vanish from Antarctica before any logical conclusions or benefits are achieve by human. Therefore, sustainable conservation of these unique plants will be advantageous for our future generations.
Table 1. Flora of east Antarctica.
Sl. No.
Algae
Lichen
Mosses
1.
Lyngbya aeustuarii
Acarospora gwynnii
Bryum argenteum
2.
Nostoc commune
Buellia pallida
Bryum pseuotriquetreum
3.
Oscillatoria limosa
Carbonea capsulata
Bryoerythrophyllum recurviroste
4.
Phormidium fragile
Lecidea cancariformis
Cedratondon purpureus
5.
Aphanothece nidulans
Lepraria membranacea
Grimmia spp.
6.
Chlorococcum
Physcia caesia
Unknown
7.
Pinnularia borealis
Polycauliona murrayi

8.

Rhizocarpon flavum

9.

Rinodina Species

10.

Umbilicaria aprina

11.

Umbilicaria decussata

12.

X. elegans

REFERENCES

  1. Ahmadjian, V., 1967, A guide to the algae occurring as lichen symbionts: isolation, culture, cultural physiology and identification. Phycologia, 6: 127-166. 
  2. Bidigare, R.R., Ondrusek, M.E., Kennicutt II, M.C., Iturriaga, R., Harvey, H.R., Hoham, R.W., and Macko, S.A., 1993, Evidence for a photo protective function for secondary carotenoids of snow algae. F. Phycol,29, 427-434.
  3. Bormann P., Peach H.J., and Stackebrandt W. 1995, Conclusions on the structure, composition and history of the Earth's crust in central Queen Maud Land. in P. Bormann and D. Fritzsche (Eds.), The Schirmacher Oasis, Queen Maud Land, East Antarctica, and its surroundings. Petermanns Geographische Mitteilungen, Erganzungsheft 289, 164-169.
  4. Broady, P. A., 1996, Diversity, distribution and dispersal of Antarctic terrestrial algae. Biodiversity & Conservation, 5:1307-1335.
  5. Buedel. B., Karsten. U., and Garcia. P. F., 1997, Ultraviolet-absorbing scytonemin and mycosporine-like amino acid derivatives in exposed, rock-inhabiting cyanobacterial lichens. Oecologia, 112:165-172.
  6. Gajananda K., 2003, Study of Atmospheric Parameters in relation to Antarctic Ecosystem over the Schirmacher Region of East Antarctica. Ph.D. Thesis, Department of Environmental Science and Engineering, Guru Jambheshwar University Hisar.
  7. Gajananda K., Kaushik. A., and Dutta. H.N., 2004, Thermal convection over East Antarctica: Potential microorganism dispersal. Aerobiologia, 20, 21-34.
  8. Gajananda K. 2007. Soil organic carbon and microbial activity: east Antarctica. European J Soil Science.58(3), 704-713.
  9. Hoham. R. W., and Brian Duval., 2001, Microbial Ecology of Snow and Freshwater Ice with Emphasis on Snow Algae. in H. G. Jones, J. W. Pomeroy, D. A. Walker, R. W. Hoham and R. Zlotin (eds.), Snow Ecology: An Interdisciplinary Examination of Snow-covered Ecosystems by Cambridge University Press.
  10. Lange. O. L., and Kappen. L., 1972, Photosynthesis of lichens from Antarctica. Antarctica Res. Ser. 20: 83-95.
  11. Ling. H.U., and Seppelt. R.D., 1993, Snow algae of the Windmill Islands, continental Antarctica. 2. Chloromonas rubroleosa sp. Nov. (Volvocales, Chlorophyta), an alga of red snow. Eur. f. Phycol., 28, 77-84.
  12. Okitsu. S., Imura S., and Ayukawa. E., 2003, Structure and dynamics of the Ceratondon purpureus-Bryum pseudotriquetrum community in the Yukidori Valley, Langhovde, continental Antarctica. Polar Biosci., 16, 49-60.
  13. Okitsu. S., Imura S., and Ayukawa. E., 2004. Micro-relief distribution of major mosses in ice-free areas along the Soya Coast, the Syowa Station area, East Antarctica. Polar Biosci., 17, 69-82.
  14. Quesada. A., and Vincent. W.F., 1997, Strategies of adaptation by Antarctic cyanobacteria to ultraviolet radiation. Eur J Phycol, 32:335-342.
  15. Resch. C.M., and Gibson. J., 1983, Isolation of the carotenoid-containing cell wall of three unicellular cyanobacteria. J Bacteriol. 155 (1): 345–350.
  16. Stoutjesdijk. Ph., and Barkman J. J., 1992, Microclimate vegetation and fauna. Opulus Press AB. Sweden.

Ustratos focus on the economic and geo-strategic analysis, security problems of the nations, economic development, the history of the world, the geopolitical conflicts and strategic issues in Europe, America, Asia, Africa, and their strategic problems. Tags:geopolitical, strategies, economies, war, military, armed, economic development, international relations, history, geography, environment, , NGO, alliances, European Union, flags, USA, United State of America
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