Checking for direct PDF access through Ovid. Abstract One of the prominent features of Antarctic soils, and one which shows their relationship with soils in other arid regions of the world, is the high content of soluble salts. These salts consist largely of the sulphates, chlorides, and nitrates of sodium, potassium, magnesium, and calcium. Almost all of the possible crystalline phases that may be formed by combination of these anions and cations are found.
Penguin colony soils had larger and more sustaining PH 3 production rates than animal-lacking soils based upon our incubation experiments, indicating that the PH 3 fluxes from penguin colonies were probably sustained by the continuous P input of penguin guano. Generally penguin and seal colonies and their active areas are devoid of vegetation due to toxic overmanuring and trampling.
Higher PH 3 emissions from penguin colonies were supported by the absence of plant P uptake, together increasing availability of P for PH 3 production Fig.
Therefore penguin activity and the deposition of their guano significantly enhanced soil MBP formation and PH 3 emissions from the local tundra soils, and furthermore altered tundra ecosystem P cycles in maritime Antarctica. The MBP production is generally assumed to relate to the microbial reduction of phosphate and the decomposition of organic phosphorus compounds under anaerobic conditions 2 , 16 , The anaerobic incubation experiments based on different inocula gave the evidence for the existence of microbially mediated production of phosphine 20 , 21 , 22 , In this study, MBP concentrations showed significant positive correlations with the bacterial abundance Fig.
The invertase is an important enzyme for regulating carbon cycle by catalyzing the hydrolysis of sucrose, the phosphatase plays an important role in the biological liberation of phosphorus in soil systems, and directly affects the decomposition and transformation of soil organic phosphorus and its bioavailability 32 , The close relations between MBP levels and invertase and phosphatase activities further indicated the bacterially mediated formation of MBP in Antarctic soils Fig. Additionally, TC, TN and TS in the soils are important sources of carbon, nitrogen and energy for the microbial metabolism in Antarctic terrestrial ecosystems, and their significant positive correlations with MBP concentrations might reflect active microbial processes correlated to PH 3 production 11 , 12 , 13 , 14 , 21 , Phosphine production in sediments or culture media could be enhanced with the addition of easily decomposable organic matter 4 , The deposition of penguin guano or seal excreta into tundra soils probably contributed to the input of organic carbon, nitrogen and sulfur, and the increase in bacterial activity, thus increased MBP production and gaseous PH 3 emissions in maritime Antarctica.
Generally MBP is a reduced, unstable phosphorus compound, and easily converted to other phosphorus compounds. It can be considered as a sub-stationary state concentration of PH 3 between production and consumption, and only a small residue of the PH 3 turnover could be observed as MBP in the soils 2. Under such circumstances, a slow migration process of PH 3 is possible in the interstitial gas of tundra soils, thus influence the phosphorus balance in the Antarctic tundra ecosystem 2 , 6. Although the quantity of PH 3 is insignificant compared to TP in this study, its influence on the transfer and nutrition preservation of P could be important over a long period.
Furthermore, the favorable conditions for high MBP production are created by physical and chemical processes related to penguin activity: sufficient supply of P, N and organic carbon from penguin guano, strong bacterial activity, penguin tramp and anaerobic environment, and can increase PH 3 fluxes from soils to the atmosphere 6 , Therefore MBP is an important gaseous link in the P biogeochemical cycles in ornithogenic tundra ecosystems of Antarctica.
The ornithogenic soils are particularly rich in phosphorus. It is estimated that penguins alone can carry 1.
The coupled production and oxidation process of PH 3 in ornithogenic soils might act as an alternative shunt associated with the P cycling, and provide a small amount of phosphate for the P-limiting tundra ecosystems in Antarctica 6 , 25 , This area is characterized by oceanic climate. Ardley Island is connected with Fildes Peninsula by a sand dam, with an area of about 2. It is one of the most important penguin colonies in maritime Antarctica. According to annual statistical data, a total of over 10, marine animals colonized on this peninsula every summer.
On the western coast are some established colonies of marine mammals, including five pinnipeds of Weddell seal Leptonychotes weddellii , elephant seal Mirounga leonine , leopard seal Hudrurga leptonyx , fur seal Arctocephalus gazella and crabeater lobodon carcinophagus During the breeding period each summer, penguin guano and seal excreta were deposited into tundra soils or catchment sediments by snow-melt water. Mosses and lichens predominate over the local vegetation.
However, the vegetation is highly absent in animal colonies due to the overmanuring and penguin or seal trampling, and only some coprophilic algae grow there The adjacent tundra areas are located outside the penguin or seal colony but where penguins, seals or other animals occasionally wander. These soils had not been disturbed and kept intact. The soil samples were divided into two portions. One portion was used to analyze soil MBP concentrations and PH 3 production rates, whereas the other portion was used to determine phosphorus fractions, enzyme activities, bacterial abundance and other soil physicochemical properties.
The samples were measured within one month after the soils were operated. The method has a detection limit of 0.
Antarctic Soils and Soil Forming Processes, Volume 8. Editor(s). J. C. F. Tedrow. First published:1 January Print ISBN |Online. Although the observations of these preliminary studies are important and illuminating, knowledge of pedologic processes as a whole on the antarctic continent.
The mass of phosphine in this gas divided by the mass of dry soil sample yields MBP. MBP in soil is commonly assumed to include absorbed phosphine, metal-phosphine complexes and inorganic phosphides that can be set free as PH 3 by analytical digestion or through bacterial action 2 , MBP was analyzed because it is linked to production, consumption and emission of free phosphine in the soils.
It is assumed to indicate a stationary state concentration of phosphine between production and consumption under natural conditions 2. The closed-chamber method 6 , 14 , 30 was used for the measurement of soil phosphine fluxes from each type of sites above. Chambers were made of opaque plastics to avoid phosphine photo-degradation. During flux measurements, the chambers were put on the bottom collars inserted into the soil with a cross-sectional area of 0.
Two parallel chambers were employed for flux measurements at each observation site Two repetitions , and their mean flux was used as the result. A gas sample was taken with ml disposable polypropylene-syringe immediately after the chamber was put on the collar, and then continuously transferred into a Tedlar bag through a three-port valve. Total six fluxes were obtained for each type of sites, and their mean fluxes were used to compare the difference between the site types Fig.
The headspace gas samples were taken four times every day for analyzing gaseous phosphine. Phosphorus fractions in the soils were measured as total phosphorus TP , inorganic phosphorus IP and organic phosphorus OP. Soil enzyme activities were based on the release and quantitative determination of the product in the reaction mixture when soil samples were incubated with substrate and buffer solution.
The 2. The samples 2. The reaction mixture consisted of 2. The copy number of soil bacterial genes in penguin colony, seal colony, their adjacent animal-lacking tundra and the background sites was quantified by a BIO-Rad CFX96 real-time PCR system 32 , Plasmid quantification standards were constructed for the primer pair by cloning PCR products resulting from the amplification of environmental DNA. DNA copy numbers of PCR product inserted containing in clones were calculated, and standard curves were generated by serial dilution 3.
The amplification of the environmental samples and standards, including the controls containing no DNA template ultrapure water only , was done in triplicate. The average amplification efficiency for Bacteria was The soil samples were mixed homogeneously for the general analyses.
The mean grain size Mz of the soils was determined by using a laser diffraction particle size analyzer LS I3 The pH was determined by ion selection electrode using a soil-to-water ratio of The ratios of phosphine fluxes R f and production rates R pr from penguin or seal colony soils to those from the background soils were calculated to indicate effects of penguin or seal on soil PH 3 fluxes and production rates.
Correlation coefficients between MBP concentrations and phosphorus fractions, enzyme activities, and other environmental factors were analyzed using Person correlation.
All statistical analyses were preformed using Microsoft Excel , OriginPro 8. Ruttenberg, K. Treatise on Geochemistry [Ruttenberg K. Glindemann, D. Phosphine in soils, sludges, biogases and atmospheric implications—a review. Evidence for phosphine production and emission from Louisiana and Florida marsh soils. Eismann, F. Soils as source and sink of phosphine.
Chemosphere 35 , — Geng, J. Simultaneous monitoring of phosphine and of phosphorus species in Taihu lake sediments and phosphine emission from lake sediments. Biogeochemistry 76 , — Zhu, R. Tropospheric phosphine and its sources in coastal Antarctica. Phosphine in the marine atmosphere along a hemispheric course from China to Antarctica.
Balancing phosphine in manure fermentation. Health Part B 32 , — Matrix bound phosphine formation and depletion in eutrophic lake sediment fermentation—simulation of different environmental factors. Anaerobe 11 , — Feng, Z. Seasonal and spatial distribution of matrix-bound phosphine and its relationship with the environment in the Changjiang River estuary. Distribution characteristics of matrix-bound phosphine along the coast of China and possible environmental controls.
Chemosphere 73 , — Li, J. Matrix-bound phosphine in sediments of the yellow sea and its coastal areas. Shelf Res. Our research contributes with the results on primitive soil and alterite development under these communities on the unconsolidated sediments in the deposition sites of the East Antarctic oasis landscape - one of the most extreme environments still hosting these organisms.
Soils with a thick insulating organic surface layer have a shallow active layer. Trends Microbiol. Our studies focused instead on wet soils at the edge of and adjacent to DV stream, lakes, and ponds the hyporheic zone. Jansson, J. Birds not only change soil conditions for microbial life, they also inoculate microorganisms through guano deposition, and the composition of this guano seems to be influenced by penguin diet.
To cope with these research topics, micromorphology seems to be the most adequate tool. Micromorphological observations are most efficient for detecting incipient or poorly developed soil processes, for example initial alteration of minerals and early stages of plant tissue decomposition.
It also provides a unique opportunity to observe the real spatial distribution and architecture of organic and mineral components within the soil epipedon that could help in the understanding SOM accumulation and stabilization in these primitive soils. These perspectives motivated us to perform the micromorphological study of the epipedons in the selected profiles of soil developed on the recent deposits under moss and lichen communities in the Schirmacher Oasis in East Antarctica, where earlier chemical analysis and dating of SOM was performed.
Based upon the obtained results we infer the formation processes of the studied organo-mineral horizons and compare them with the possible soil analogues in other geographical regions and in the landscapes of geological past. At the present time, ice-free lands in Antarctica with a total area of km 2 constitute 0. An Antarctic oasis is a substantial ice-free area that is separated from the ice sheet by a distinct ablation zone and is kept from snow by ablation due to low albedo and a positive radiation balance e.
Gore and Pickard, Oasis can occupy an area from several tens to several thousand square kilometers. QML is the fourth largest ice-free territory of Antarctica, comprised of 3, km 2 6. The total length of oasis is 18 km and its width varies from 0. The territory stretches in a sub-latitudinal direction along the slope of the continental ice shelf. From the north the oasis borders the Lazarev Ice Shelf, which separates it from the sea. The Schirmacher Oasis contains hummocky terrain, with the hills ranging from 10 to m in relief.
The highest point is Mt. Rebristaya at m. Schirmacher Oasis is one of the coldest Antarctic oases, because of its high latitude, trans-shelf location and the fact it is surrounded by ice. The mean annual air temperature at Novolazarevskaya station is The absolute minimum temperature over the period of observation to present was At low temperatures during the summer period, the soil surface is warmed from the intensive solar radiation. On north-facing slopes, rock temperatures of We observed soil surface temperatures between The mean annual wind speed is about 10 m s During the summer wind speeds can reach 30 to 35 m s -1 and in winter 50 to 55 m s The mean annual precipitation is mm, but it is only 10 mm during the summer months of December and January.
Evaporation rates vary from to mm yr -1 Bormann and Fritzsche, ; Verkulich et al. The aridity of the region is due to the positive radiation balance, the low amounts of precipitation and humidity, strong winds, and high evaporation rates.