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

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˚S, 38˚E). 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 CO 2 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 CO 2 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.

Microbial biomass and basal respiration of selected Sub-Antarctic and Antarctic soils in the areas of some Russian polar stations

“…They also agree well with previously published data on the metabolic activity of the Sub-Antarctic and Antarctic (Gilichinsky et al, 2010). Not only chemical properties of soil affect soil respiration levels (Lubbe and Smith, 2012); climatic conditions do too (temperature and soil moisture). This was especially important for comparing the level of basal respiration in standardized laboratory conditions for soils from different natural zones (this gives us an opportunity to compare soils of different climates under the same experimental conditions), but not in a field, while the climatic conditions of the expedition route were different.…”

“…Soil respiration has been predicted by organic phosphorous and total nitrogen content in Sub-Antarctic soils for habitat comparison (Lubbe and Smith, 2012). Latitudinal research of different Antarctic soils shows that the temperature sensitivity of microorganisms increases with mean annual soil temperature, suggesting that bacterial communities from colder regions were less temperature sensitive than those from the warmer regions (Rinnan et al, 2009).…”

Organic carbon and microbiome in tundra and forest–tundra permafrost soils, southern Yamal, Russia

“…The data on soil respiration are crucial for soil carbon turnover modelling to simulate greenhouse gas emissions and soil organic dynamics under conditions of a changing climate. Chemical properties of soil are not the only factors affecting soil respiration levels (Lubbe & Smith 2012). Climatic conditions-temperature and soil moisture-are also important (Abakumov & Mukhametova 2014).…”

Aeolian processes and landforms in the sub-Antarctic: preliminary observations from Marion Island

“…Pedogenesis on Marion Island is limited (Gribnitz et al 1986;Lubbe 2010), but cohesionless volcanic (scoria) materials, with their high permeability (Boelhouwers et al 2008), may be extremely susceptible to transport by wind. Meteorological observations at the scientific station on the eastern coast of the island indicate that winds mostly originate from a westerly to north-westerly direction, which is related to the predominant synoptic conditions Nel et al 2009;Nel 2012).…”