Abstract:
An analysis of bedrock and associated soils was conducted at a series of coastal localities in East Antarctica as well as further inland in the Prince Charles Mountains. Protozoans and micrometazoans were extracted from soil samples and an assessment made of their ecological relations with each other and with soil characteristics. Mineral soils, regardless of topographic elevation and proximity ... to the coast, were characterised by large gravel fractions (fragments of underlying bedrock) and minimal clay fractions, implying that these soils were predominantly the products of physical weathering, with little chemical alteration. Only where humans, dogs or birds contributed organic matter were there elevated concentrations of nitrogen, phosphorus or organic matter. Generally, mineral nitrogen did not seem to have resulted from microbial mineralisation, but at some sites there was evidence that atmospheric nitrate had been concentrated by sublimination of snow. Water-soluble and dilute acid-soluble phosphorous concentrations were surprisingly high for such organically poor soils. There was a sufficiently large labile pool of common macronutrients to sustain the autotrophic activity likely to occur within the bounds of prevailing temperatures and moisture; thus nutrients are not likely to be limiting for these soil communities. There was a limited fauna. Flagellates were rare and ciliates occurred only in the coastal areas sampled, whereas amoebae were found over a greater geographic and elevational span. Micrometazoans such as rotifers, tardigrades and nematodes were more common in coastal soils than in those further inland, but occurred in soils over most of the naturally occurring range of soil moistures, acidities, nutrient levels, electrolyte levels and organic contents. Exceptions were the exclusion of rotifers from alkaline soils with high nutrient levels, and the tendency of nematodes to be absent from soils with low pH. Tardigrades were found at almost all levels of soil characterisitcs. The occurrence of these metazoan phyla under such a range of environments probably resulted from their known capacity to alternate between endurance of inclement conditions in a state of deep dormancy (anhydrobiosis), and taking advantage of ephemeral favourable conditions by temporarily resuming metabolic activity. The conditions measured in soils containing micrometazoans may merely indicate thise conditions these animals can survive while dormant, not those under which active animals can carry out vital processes. In some localities there were positive associations between various taxon-pairs of metazoans and protozoans, whereas at others their occurrences seemed to be random with respect to each other.
The fields in this dataset are: AMOEBAE ANHYDROBIOSIS MICROMETAZOAN SOIL TARDIGRADES location site sample SAMPLE CODE PERCENT DRY WEIGHT PERCENT VOLUME bedrock type quartz plagioclase K-feldspar garnet biotite pyroxene homblende others rock type(field sample number)catalogue NO material Granitic Gneiss (BI ) Amphibolite (B4) Quartz Sandstone (J1) Garnet Pegmatite (W3) pH KCI(1:5) pH H20(1:5) micro siemens cm-1(1:5) Water-Sol. P(1:5)(micro grams mL-1) Water-Sol. K(1:5)(micro grams mL-1) Water-Sol. K(1:5)(micro grams g-1)Water+ Sol.K(cmol.kg-1) Colour (Munsell) Total N(micro grams g-1) Min. (KCI)NH4-N(micro grams g-1) Min. N(KCI)NH3-N(micro grams g-1) Dilute Acid-Sol. P(micro grams g-1) Loss on ignition(%) number of samples from which extractions were made AMOEBAE CILIATES NUMBER (%) OF SAMPLES CONTAINING:ROTIFERS NUMBER (%) OF SAMPLES CONTAINING:TARDIGRADES NUMBER (%) OF SAMPLES CONTAINING:NEMATODES VARIABLES RHO P
HAROLD
HEATWOLE Role:
INVESTIGATOR
Role:
TECHNICAL CONTACT
Role:
DIF AUTHOR
Phone:
+1 919 515 2741
Fax:
+1 919 515 5327
Email:
harold_heatwole at ncsu.edu
Contact Address:
DEPT OF ZOOLOGY, COLLEGE OF
BOX 7617
NORTH CAROLINA STATE UNIVERSITY
AGRICULTURE & LIFE SCIENCES City:
RALEIGH
Province or State:
NC
Postal Code:
27695-7617
Country:
UNITED STATES OF AMERICA
Publications/References
Heatwole, H., Alter, D., Charley, J., Stephenson, N.C.N., Bedford, J., O'Donoghue, P., Miller, W.R. and Reay, F. (1999), From bedrock to biota: weathering, physico-chemical properties, protozoans and micrometazoans of some soils of East Antarctica, ANARE Reports, 140
Miller, W.R. and Heatwole, H. (1995), Tardigrades of the Australian Antarctic Territories: the Mawson Coast, East Antarctica., Invertebrate Biology, 114, 1, 27-38
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