Structure and Function of Terrestrial Biotic Communities
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 othe...
| Other Authors: | , , |
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| Format: | Dataset |
| Language: | unknown |
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Australian Antarctic Data Centre
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| Online Access: | https://researchdata.ands.org.au/structure-function-terrestrial-biotic-communities/700151 https://doi.org/10.4225/15/57E4C573B3B81 https://data.aad.gov.au/metadata/records/ASAC_37 http://nla.gov.au/nla.party-617536 |
| Summary: | 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 for this dataset are: site conductivity bedrock type quartz garnet pyroxene homblende biotite K-feldspar plagioclase other catalogue number material USDA texture class % dry weight % volume colour (munsell) Total N(micro grams g-1) Minimum N (KCl) NH3-N(micro grams g-1) Minimum N (KCl) NH4-N(micro grams g-1) Dilute acid sol. P(micro grams g-1) loss on ignition (%) amoebae ciliates tardigrades nematodes associations rotifers samples granitic gneiss Amphibolite (B4) Quartz sandstone (J1) Garnet Pegmatite (W3) >19.05mm 19.05-11.13mm 11.13-9.60mm 9.60-5.66mm 5.66-4.76mm 4.76-4.00mm 4.00-2.80mm 2.80-2.00mm less than 2.00mm 2.00 mm- 212 micro meters 212 micro meters- 20 micro meters 20 micro meters - 2 micro meters less than 2 micro meters mont. verm. chlor. Illite Kaol. Int. K:I sepiol. int MI int I:C Int M:C Sample code 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) N grand total variables correlation with elevation correlation without elevation RHO P correlations of: soil moisture organic matter (LOI) water soluble P Acid soluble P exchangeable K water soluble K (wt) nitrate N ammonia N soil moisture and organic matter Soil moisture and soluble P soil moisture and acid-soluble P soil moisture and pH (water) soil moisture and pH (KCl) organic matter and acid-soluble P organic matter and total N organic matter and pH (water) organic matter and pH (KCl) soluble P and acid-soluble P soluble P and total N soluble P and pH (water) soluble P and pH (KCl) acid-soluble P and total N acid-soluble P and pH (water) acid-soluble P and pH (KCl) Total N and pH (water) Total N and pH (KCl) pH (water) and pH (KCl) coastal PCM observed expected X2 (X squared) +/- |
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