scholarly journals Persistence of labile organic matter and microbial biomass in Antarctic shelf sediments: evidence of a sediment ‘food bank’

2005 ◽  
Vol 300 ◽  
pp. 3-19 ◽  
Author(s):  
SL Mincks ◽  
CR Smith ◽  
DJ DeMaster
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Food Bank ◽  
Labile Organic Matter ◽  
Shelf Sediments ◽  
Antarctic Shelf

scholarly journals Changes in Soil Labile Organic Matter as Affected by 50 Years of Fertilization with Increasing Amounts of Nitrogen

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2026
Author(s):  
Nikola Koković ◽  
Elmira Saljnikov ◽  
Frank Eulenstein ◽  
Dragan Čakmak ◽  
Aneta Buntić ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Quality Parameters ◽  
Light Fraction ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Sensitivity Index ◽  
Strong Impact ◽  
Labile Organic Matter ◽  
C And N

Microbially mediated soil organic matter is an extremely sensitive pool that indicates subtle changes in the quality parameters responsible for the soil’s ecological and productive functions. Fifty years of mineral fertilization of a wheat-corn cropping system has a strong impact on soil quality parameters. The goal of the research was to study the dynamics and quality of soil biological parameters affected by increasing amounts of mineral nitrogen. Soil respiration, potentially mineralizable C and N, microbial biomass C and N and light-fraction OM on Cambisol were analyzed in the following treatments: (1) Control (without fertilization); (2) NPK (60/51/67); (3) NPK (90/51/67); (4) NPK (120/51/67); (5) NPK (150/51/67 kg ha−1). The parameters studied were significantly affected by the long-term application of mineral fertilizer compared with both the control and the adjacent native soil. The highest amounts of nitrogen (N150) did not significantly differ from N120 and N90 for most of the parameters studied. Potentially mineralizable C represented the largest labile carbon pool, while microbial biomass N was the largest labile nitrogen pool. The mineralization rates for C and N were oppositely distributed over the seasons. The sensitivity index correlated with the amount of light-fraction OM. The results give a deeper insight into the behavior and distribution of different pools of labile SOM in the agro-landscapes and can serve as a reliable basis for further research focused on zero soil degradation.

scholarly journals Nitrogen Immobilisation and Microbial Biomass Build-Up Induced by Miscanthus x giganteus L. Based Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Triticum Aestivum L ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Miscanthus X Giganteus ◽  
Organic Fertilisers ◽  
Biomass N ◽  
Set Up

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.

Microbial and biochemical changes induced by rotation and tillage in a soil under barley production

1993 ◽  
Vol 73 (1) ◽  
pp. 39-50 ◽  
Author(s):  
D. A. Angers ◽  
N. Bissonnette ◽  
A. Légère ◽  
N. Samson
Keyword(s):  
Alkaline Phosphatase ◽  
Organic Matter ◽  
Microbial Biomass ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Soil Layer ◽  
Red Clover ◽  
Organic C ◽  
Top Soil ◽  
Total Organic C

Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase

scholarly journals Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

2010 ◽  
Vol 7 (11) ◽  
pp. 3473-3489 ◽  
Author(s):  
J. Holtvoeth ◽  
H. Vogel ◽  
B. Wagner ◽  
G. A. Wolff
Keyword(s):  
Organic Matter ◽  
Lipid Biomarkers ◽  
Lake Ohrid ◽  
Labile Organic Matter ◽  
Glacial Sediments ◽  
Plant Matter ◽  
Lipid Biomarker ◽  
First Results ◽  
Near Shore

Abstract. Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event). Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats), in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.

scholarly journals Spatiotemporal variability of sedimentary organic matter supply and recycling processes in coral reefs of Tayrona National Natural Park, Colombian Caribbean

2014 ◽  
Vol 11 (11) ◽  
pp. 2977-2990 ◽  
Author(s):  
E. Bayraktarov ◽  
C. Wild
Keyword(s):  
Organic Matter ◽  
Coral Reef ◽  
Coastal Upwelling ◽  
Sediment Traps ◽  
Sedimentary Organic Matter ◽  
Spatiotemporal Variability ◽  
Water Current ◽  
Labile Organic Matter ◽  
Natural Park ◽  
River Mouths

Abstract. Sediments are fundamental for the function of oligotrophic coral reef ecosystems because they are major places for organic matter recycling. The Tayrona National Natural Park (TNNP, Colombian Caribbean) is located between the population center Santa Marta (>455 000 inhabitants) in the southwest and several river mouths in the east. Here, coral reef sediments experience pronounced changes in environmental conditions due to seasonal coastal upwelling, but knowledge of relevant spatiotemporal effects on organic matter supply to the sediments and recycling processes is not available. Therefore, sediment traps were deployed monthly over 14 months complemented by assessment of sedimentary properties (e.g., porosity, grain size, content of particulate organic matter and pigments) and sedimentary O2 demand (SOD) at water-current-exposed and sheltered sites along distance gradients (12–20 km) to Santa Marta and the eastern river mouths (17–27 km). Findings revealed that seasonal upwelling delivered strong (75–79% of annual supply) pulses of labile organic matter mainly composed of fresh phytoplankton detritus (C : N ratio 6–8) to the seafloor. Sedimentary chlorophyll a contents and SOD increased significantly with decreasing distance to the eastern rivers, but only during upwelling. This suggests sedimentary organic matter supply controlled by nutrient-enriched upwelling waters and riverine runoff rather than by the countercurrent-located city of Santa Marta. Organic matter pulses led to significantly higher SOD (more than 30%) at the water-current-sheltered sites as compared to the exposed sites, ensuing a rapid recycling of the supplied labile organic matter in the permeable silicate reef sands.

scholarly journals ORCHIMIC (v1.0), a microbe-driven model for soil organic matter decomposition designed for large-scale applications

2018 ◽  
Author(s):  
Ye Huang ◽  
Bertrand Guenet ◽  
Philippe Ciais ◽  
Ivan A. Janssens ◽  
Jennifer L. Soong ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Input Data ◽  
Priming Effect ◽  
Temporal Dynamics ◽  
Litter Input ◽  
Decomposition Models ◽  
Soc Stock ◽  
Global Vegetation ◽  
Soc Decomposition

Abstract. The role of soil microorganisms in regulating soil organic matter (SOM) decomposition is of primary importance in the carbon cycle, and in particular in the context of global change. Modelling soil microbial community dynamics to simulate its impact on soil gaseous carbon (C) emissions and nitrogen (N) mineralization at large spatial scales is a recent research field with the potential to improve predictions of SOM responses to global climate change. We here present a SOM model called ORCHIMIC whose input data that are consistent with those of global vegetation models. The model simulates decomposition of SOM by explicitly accounting for enzyme production and distinguishing three different microbial functional groups: fresh organic matter (FOM) specialists, SOM specialists, and generalists, while implicitly also accounting for microbes that do not produce extracellular enzymes, i.e. cheaters. This ORCHIMIC model and two other organic matter decomposition models, CENTURY (based on first order kinetics and representative for the structure of most current global soil carbon models) and PRIM (with FOM accelerating the decomposition rate of SOM) were calibrated to reproduce the observed respiration fluxes from FOM and SOM and their possible interactions from incubation experiments of Blagodatskaya et al. (2014). Among the three models, ORCHIMIC was the only one that captured well both the temporal dynamics of the respiratory fluxes and the magnitude of the priming effect observed during the incubation experiment. ORCHIMIC also reproduced well the temporal dynamics of microbial biomass. We then applied different idealized changes to the model input data, i.e. a 5 K stepwise increase of temperature and/or a doubling of plant litter inputs. Under 5 K warming, ORCHIMIC predicted a 0.002 K−1 decrease in the C use efficiency (defined as the ratio of C allocated to microbial growth to the sum of C allocated to growth and respiration) and a 3 % loss of SOC. Under the double litter input scenario, ORCHIMIC predicted a doubling of microbial biomass, while SOC stock increased by less than 1 % due to the priming effect. This limited increase in SOC stock contrasted with the proportional increase in SOC stock as modelled by the conventional SOC decomposition model (CENTURY), which cannot reproduce the priming effect. If temperature increased by 5 K and litter input is doubled, the model predicted almost the same loss of SOC as when only temperature was increased. These tests suggest that the responses of SOC stock to warming and increasing input may differ a lot from those simulated by conventional SOC decomposition models, when microbial dynamics is included. The next step is to incorporate the ORCHIMIC model into a global vegetation model to perform simulations for representative sites and future scenarios.

Temperature effects on organic matter and microbial biomass dynamics in temperate and tropical soils

1998 ◽  
Vol 30 (10-11) ◽  
pp. 1309-1315 ◽  
Author(s):  
B. Grisi ◽  
C. Grace ◽  
P.C. Brookes ◽  
A. Benedetti ◽  
M.T. Dell'abate
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Temperature Effects ◽  
Tropical Soils ◽  
Biomass Dynamics

Soil microbial biomass—Interpretation and consideration for soil monitoring

Soil Research ◽  
2011 ◽  
Vol 49 (4) ◽  
pp. 287 ◽  
Author(s):  
V. Gonzalez-Quiñones ◽  
E. A. Stockdale ◽  
N. C. Banning ◽  
F. C. Hoyle ◽  
Y. Sawada ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Soil Microorganisms ◽  
Soil Microbial Biomass ◽  
Biological Function ◽  
Anthropogenic Change ◽  
Soil Monitoring ◽  
Soil Microbial ◽  
Quality Assessments ◽  
The Impact

Since 1970, measurement of the soil microbial biomass (SMB) has been widely adopted as a relatively simple means of assessing the impact of environmental and anthropogenic change on soil microorganisms. The SMB is living and dynamic, and its activity is responsible for the regulation of organic matter transformations and associated energy and nutrient cycling in soil. At a gross level, an increase in SMB is considered beneficial, while a decline in SMB may be considered detrimental if this leads to a decline in biological function. However, absolute SMB values are more difficult to interpret. Target or reference values of SMB are needed for soil quality assessments and to allow ameliorative action to be taken at an appropriate time. However, critical values have not yet been successfully identified for SMB. This paper provides a conceptual framework which outlines how SMB values could be interpreted and measured, with examples provided within an Australian context.

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