Geoscience Reference
In-Depth Information
9.2.2
Biota
Vegetation is an important soil-forming factor in Antarctica by virtue of its presence
or its absence. Two higher plants (
Deschampsia Antarctica
and
Colobanthus quiten-
sis
grasses) are found only along the WAP and the South Orkney and South Shetland
Islands. Small (10-1,000 m
2
) patches of continuous vegetation cover, primarily
mosses and lichens, may occur in coastal areas of regions 1, 2, 3, 4, 7, and 8. There
are 427 species of lichens in Antarctica, 40 % of which are endemic (Nayaka and
Upreti
2005
). Algae infl uence soil development in these same areas. Endolithic
lichens produce organic matter and initiate chemical and physical weathering
throughout Antarctica. Microorganisms are present in nearly all soils of Antarctica,
except possibly in old soils with pronounced salt accumulation.
Birds, primarily penguins but also skua gulls and petrels, contribute organic matter,
phosphates, and Na and are important in coastal areas of Antarctica (Beyer
2000
;
Beyer et al.
2000
). Ornithogenic soils are best expressed directly under active Adélie
(
Pygoscelis adeliae
), chinstrap (
P. antarctica
), or gentoo (
P. papua
) penguin rookeries
but are also commonly found at abandoned rookeries, where ornithogenic soils remain
hundreds to thousands of years later (Myrcha and Tatur
1991
). About 200 million kg
of C and 20 million kg of P are deposited annually in rookeries of maritime Antarctica
from Adélie and Chinstrap penguin excrement (Pietr et al.
1983
; Myrcha and Tatur
1991
). The high levels of seabird manure are a function of nutrient upwelling at the
Antarctic Convergence. Along the continental shelf of the Antarctic Peninsula; nutri-
ents feed large blooms of phytoplankton to sustain Antarctic krill, which are subse-
quently consumed and excreted by seabirds to develop the soils of maritime Antarctica.
9.2.3
Parent Materials and Time
Most of the soils in coastal regions of Antarctica are of Late Glacial Maximum age,
or younger. However, strongly developed soils of early Pleistocene to Miocene age
occur in the Sør Rondane Mountains (region 1), the southern Prince Charles
Mountains and Grove Mountains (region 3), the Thiel Mountains and Pensacola
Mountains (region 5a), and the Transantarctic Mountains (region 5b). Parent
material results in unique soils in areas with sulfi de rocks (sulfuric subgroups of
soils), carbonates (calcifi cation in coastal areas and north Victoria Land), and sandy
materials (Gelipsamments, Psammorthels, and Psammoturbels).
9.3
Soil Properties
In this section soil properties will be considered for each of the three broad climatic
regions, including the western Antarctic Peninsula and the offshore islands, which
comprise 1,700 km
2
, or 3.4 % of the total ice-free area of the continent; coastal East
