Enzymatic activities and microbial communities in an Antarctic dry valley soil: Responses to C and N supplementation

Hopkins, D.W., Sparrow, A.D., Shillam, L.L., English, L.C., Dennis, P.G., Novis, P., Elberling, B., Gregorich, E.G. and Greenfield, L.G. (2008) Enzymatic activities and microbial communities in an Antarctic dry valley soil: Responses to C and N supplementation. Soil Biology and Biochemistry, 40 9: 2130-2136. doi:10.1016/j.soilbio.2008.03.022


Author Hopkins, D.W.
Sparrow, A.D.
Shillam, L.L.
English, L.C.
Dennis, P.G.
Novis, P.
Elberling, B.
Gregorich, E.G.
Greenfield, L.G.
Title Enzymatic activities and microbial communities in an Antarctic dry valley soil: Responses to C and N supplementation
Journal name Soil Biology and Biochemistry   Check publisher's open access policy
ISSN 0038-0717
1879-3428
Publication date 2008
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.soilbio.2008.03.022
Volume 40
Issue 9
Start page 2130
End page 2136
Total pages 7
Place of publication Kidlington, Oxford, United Kingdom
Publisher Pergamon
Collection year 2009
Language eng
Subject 1111 Nutrition and Dietetics
1303 Specialist Studies in Education
2303 Ecology
Abstract The soils of the Antarctic dry valleys are exposed to extremely dry and cold conditions. Nevertheless, they contain small communities of micro-organisms that contribute to the biogeochemical transformations of the bioelements, albeit at slow rates. We have determined the dehydrogenase, β-glucosidase, acid and alkaline phosphatase and arylsulphatase activities and the rates of respiration (CO2 production) in laboratory assays of soils collected from a field experiment in an Antarctic dry valley. The objective of the field experiment was to test the responses of the soil microbial community to additions of C and N in simple (glucose and NH4Cl) and complex forms (glycine and lacustrine detritus from the adjacent lake comprising principally cyanobacterial necromass). The soil samples were taken 3 years after the experimental treatments had been applied. In unamended soil, all enzyme activities and respiration were detected indicating that the enzymatic capacity to mineralize organic C, P and S compounds existed in the soil, despite the very low organic matter content. Relative to the control (unamended soil), respiration was significantly increased by all the experimental additions of C and N except the smallest NH4Cl addition (1 mg N g-1 soil) and the smallest detritus addition (1.5 mg C g-1 soil and 0.13 mg N g-1 soil). The activities of all enzymes except dehydrogenase were increased by C and combined large C (10 mg C g-1 soil) and N additions, but either unchanged or diminished by addition of either N only or N (up to 10 mg N g-1 soil) with only small C (1 mg C g-1 soil) additions in the form of glucose and NH4Cl. This suggests that in the presence of a large amount of N, the C supply for enzyme biosynthesis was limited. When normalized with respect to soil respiration, only arylsulphatase per unit of respiration showed a significant increase with C and N additions as glucose and NH4Cl, consistent with S limitation when C and N limitations have been alleviated. Based on the positive responses of enzyme activity, detritus appeared to provide either conditions or resources which led to a larger biological response than a similar amount of C and more N added in the form of defined compounds (glucose, NH4Cl or glycine). Assessment of the soil microbial community by ester-linked fatty acid (ELFA) analysis provided no evidence of changes in the community structure as a result of the C and N supplementation treatments. Thus the respiration and enzyme activity responses to supplementation occurred in an apparently structurally stable or unresponsive microbial community.
Keyword β-Glucosidase
Acid phosphatase
Alkaline phosphatase
Antarctica
Arylsulphatase
Dehydrogenase
Ester-linked fatty acids
Soil respiration
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
 
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Created: Tue, 04 Mar 2014, 15:50:57 EST by Paul Dennis on behalf of School of Agriculture and Food Sciences