Field Soil Respiration Rate on a Sub-Antarctic Island: Its Relation to Site Characteristics and Response to Added C, N and P

Andrea Lubbe, Valdon R. Smith

Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa..

DOI: 10.4236/ojss.2012.22023                

Abstract

Botanical, soil chemistry and soil microbiology variables were tested as predictors of in situ soil respiration rate in the various terrestrial habitats on sub-Antarctic Marion Island (47^oS, 38^oE). Inorganic P and total N concentration were the best predictors amongst the chemistry variables and bacteria plate count the best of the microbiology variables. However, while these chemistry and microbiology variables could accurately predict soil respiration rate for particular habitats, they proved inadequate predictors across the whole range of habitats. The best suite of predictors comprised only botanical variables (relative covers of five plant guilds) and accounted for 94% of the total across-habitat variation in soil respiration rate. Mean field soil respiration rates (2.1 - 15.5 mmol CO₂ m^-2 h^-1) for habitats not influenced by seabirds or seals are similar to rates in comparable Northern Hemisphere tundra habitats. Seabird and seal manuring enhances soil respiration rates to values (up to 27.6 mmol CO₂ m^-2 h^-1) higher than found at any tundra site. Glucose, N, P or N plus P were added to three habitats with contrasting soil types; a fellfield with mineral, nutrient-poor soil, a mire with organic, nutrient-poor soil and a shore-zone herbfield heavily manured by penguins and with organic, nutrient-rich soil. Glucose addition stimulated soil respiration in the fellfield and mire (especially the former) but not in the coastal herbfield soil. N and P, alone or together, did not stimulate respiration at any of the habitats, but adding glucose to fellfield soils that had previously been fortified with P or NP caused a similar increase in respiration rate, which was greater than the increase when adding glucose to soils fortified only with N. This suggests that fellfield soil respiration is limited by P rather than N, and that there is no synergism between the two nutrients. For the mire and coastal herbfield, adding glucose to soils previously fortified with N, P or NP did not enhance rates more than adding glucose to soils that had received no nutrient pre-treatment.

Keywords

Soil Respiration; Sub-Antarctic Island; Soil Moisture Content; Soil Nutrient Status; N Limitation; P Limitation; C Limitation; Seal and Seabird Manuring

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	V. R. Smith and M. G. Steyn, “Soil Microbial Counts in Relation to Site Characteristics at a Sub-Antarctic Island,” Microbial Ecology, Vol. 8, No. 3, 1982, pp. 253-266. doi:10.1007/BF02011429
[2]	D. D. French and V. R. Smith, “Bacterial Populations in Soils of a Sub-Antarctic Island,” Polar Biology, Vol. 6, No. 2, 1986, pp. 75-82. doi:10.1007/BF00258256
[3]	D. C. Grobler, D. F. Toerien and V. R. Smith, “Bacterial Activity in Soils of a Sub-Antarctic Island,” Soil Biology and Biochemistry, Vol. 19, No. 5, 1987, pp. 485-490. doi:10.1016/0038-0717(87)90089-7
[4]	V. R. Smith, M. Steenkamp and D. D. French, “Soil Decomposition Potential in Relation to Environmental Factors on Marion Island (Sub-Antarctic),” Soil Biology and Biochemistry, Vol. 25, No. 11, 1993, pp. 1619-1633. doi:10.1016/0038-0717(93)90018-7
[5]	V. R. Smith and M. Steenkamp, “Macroinvertebrates and Litter Nutrient Release on a Sub-Antarctic Island,” South African Journal of Botany, Vol. 58, 1992, pp. 105-116.
[6]	V. R. Smith, “Introduced Slugs and Indigenous Caterpillars as Facilitators of Carbon and Nutrient Mineralisation on a Sub-Antarctic Island,” Soil Biology and Biochemistry, Vol. 39, No. 2, 2007, pp. 709-713. doi:10.1016/j.soilbio.2006.09.026
[7]	V. R. Smith, “Soil Respiration and its Determinants on a Sub-Antarctic Island,” Soil Biology and Biochemistry, Vol. 35, No. 1, 2003, pp. 77-91. doi:10.1016/S0038-0717(02)00240-7
[8]	V. R. Smith, “Moisture, Carbon and Inorganic Nutrient Controls of Soil Respiration at a Sub-Antarctic Island,” Soil Biology and Biochemistry, Vol. 37, No. 1, 2005, pp. 81-91. doi:10.1016/j.soilbio.2004.07.026
[9]	V. R. Smith and M. Steenkamp, “Classification of the Terrestrial Habitats on Sub-Antarctic Marion Island Based on Vegetation and Soil Chemistry,” Journal of Vegetation Science, Vol. 12, No. 2, 2001, pp. 181-198. doi:10.2307/3236603
[10]	B. H. Svensson, A. K. Veum and S. Kjelvik, “Carbon Losses from Tundra Soils,” In: F. E. Wielgolaski, Ed., Fennoscandian Tundra Ecosystems. Part 1. Plants and Microorganisms. Ecological Studies, Vol. 16, Springer, Berlin, Heidelberg, New York, 1975, pp. 279-286.
[11]	L. Illeris, A. Michelsen and S. Jonasson, “Soil plus Root Respiration and Microbial Biomass following Water, Nitrogen and Phosphorus Application at a High Arctic Semi Desert,” Biogeochemistry, Vol. 65, No. 1, 2003, pp. 15- 29. doi:10.1023/A:1026034523499
[12]	E. D. Vance and F. S. Chapin III, “Substrate Limitations to Microbial Activity in Taiga Forest Floors,” Soil Biology and Biochemistry, Vol. 33, No. 2, 2001, pp. 173-188. doi:10.1016/S0038-0717(00)00127-9
[13]	S. Sj?gersten and P. A. Wookey, “Climatic and Resource Quality Controls on Soil Respiration Across a Forest- Tundra Ecotone in Swedish Lapland,” Soil Biology and Biochemistry, Vol. 34, No. 11, 2002, pp. 1633-1646. doi:10.1016/S0038-0717(02)00147-5
[14]	C. Corradi, O. Kolle, K. Walter, S. A. Simov and E.-D. Schulze, “Carbon Dioxide and Methane Exchange of a North-East Siberian Tussock Tundra,” Global Change Biology, Vol. 11, No. 11, 2005, pp. 1910-1925.
[15]	V. R. Smith, “Terrestrial and Freshwater Primary Production and Nutrient Cycling,” In: S. L. Chown and P. W. Froneman, Eds., The Prince Edward Islands: Land-Sea Interactions in a Changing Ecosystem, African SunMedia, Stellenbosch, 2008, pp. 181-214.
[16]	B. J. Huntley, “Vegetation,” In: E. M. Van Zinderen Bakker, et al., Eds., Marion and Prince Edward Islands, A.A. Balkema, Cape Town, 1971, pp. 98-160.
[17]	V. R. Smith, M. Steenkamp and N. J. M. Gremmen, “Terrestrial Habitats on Sub-Antarctic Marion Island: Their Vegetation, Edaphic Attributes, Distribution and Response to Climate Change,” South African Journal of Botany, Vol. 67, No. 4, 2001, pp. 641-654.