Effect of temperature on the decomposition rate of labile and stable organic matter in an agrochernozem

2014 ◽  
Vol 47 (5) ◽  
pp. 416-424 ◽  
Author(s):  
A. A. Larionova ◽  
A. K. Kvitkina ◽  
I. V. Yevdokimov ◽  
S. S. Bykhovets ◽  
A. F. Stulin
Keyword(s):  
Organic Matter ◽  
Decomposition Rate ◽  
Effect Of Temperature ◽  
Stable Organic Matter

scholarly journals Effects of pH on aquatic biodegradation processes

2009 ◽  
Vol 6 (1) ◽  
pp. 491-514 ◽  
Author(s):  
R. F. Krachler ◽  
R. Krachler ◽  
A. Stojanovic ◽  
B. Wielander ◽  
A. Herzig
Keyword(s):  
Organic Matter ◽  
Lake Water ◽  
Decomposition Rate ◽  
Degradation Mechanism ◽  
Ph Dependence ◽  
Degradation Process ◽  
Plant Litter ◽  
Lake Basin ◽  
Causal Connection ◽  
Ph Values

Abstract. To date, little is known about the pH-stimulated mineralization of organic matter in aquatic environments. In this study, we investigated biodegradation processes in alkaline waters. Study site is a large shallow soda lake in Central Europe (Neusiedler See/Ferto). The decomposition rate of plant litter was measured as a function of pH by incubating air-saturated lake-water samples in contact with Phragmites litter (leaves) from the littoral vegetation. All samples showed high decomposition rates (up to 32% mass loss within 35 days) and a characteristic two-step degradation mechanism. During the degradation process, the solid plant litter was dissolved forming humic colloids. Subsequently, the humic colloids were mineralized to CO2 in the water column. The decomposition rate was linearly related to pH. Increasing pH values accelerated significantly the leaching of humic colloids as well as the final degradation process. The observed two-step mechanism controls the wetland/lake/air carbon fluxes, since large quantities of humic colloids are currently produced in the reed belt, exported through wind-driven circulations and incorporated into the open lake foodweb. At present, the lake is rapidly shrinking due to peat deposition in the littoral zone, whereas it has been resistant to silting-up processes for thousands of years. In order to investigate the cause of this abrupt change, the chemical composition of the lake-water was measured during 1995–2007. A thorough analysis of these data revealed that major lake-water discharges through the lake's artificial outlet channel led to a decline in salinity and alkalinity. According to our estimates, the lake's original salinity and alkalinity was 70–90% higher compared to the present conditions, with the consequence of substantially lower pH values in the present lake. The observed pH dependence of reed litter biodegradation rates points to a causal connection between low pH values and accumulation of peat in the lake basin. Our results suggest that the pH stimulated remineralisation of organic matter plays a major role in maintaining the long-term integrity of saline lake/wetland systems.

scholarly journals Effects of temperature and organic pollution on nutrient cycling in marine sediments

2015 ◽  
Vol 12 (15) ◽  
pp. 4565-4575 ◽  
Author(s):  
C. Sanz-Lázaro ◽  
T. Valdemarsen ◽  
M. Holmer
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Nutrient Cycling ◽  
Water Column ◽  
Temperature Rise ◽  
Nutrient Release ◽  
Organic Pollution ◽  
Coastal Sediments ◽  
Effect Of Temperature ◽  
Climate Change Scenarios

Abstract. Increasing ocean temperature due to climate change is an important anthropogenic driver of ecological change in coastal systems. In these systems sediments play a major role in nutrient cycling. Our ability to predict ecological consequences of climate change is enhanced by simulating real scenarios. Based on predicted climate change scenarios, we tested the effect of temperature and organic pollution on nutrient release from coastal sediments to the water column in a mesocosm experiment. PO43− release rates from sediments followed the same trends as organic matter mineralization rates, increased linearly with temperature and were significantly higher under organic pollution than under nonpolluted conditions. NH4+ release only increased significantly when the temperature rise was above 6 °C, and it was significantly higher in organic polluted compared to nonpolluted sediments. Nutrient release to the water column was only a fraction from the mineralized organic matter, suggesting PO43− retention and NH4+ oxidation in the sediment. Bioturbation and bioirrigation appeared to be key processes responsible for this behavior. Considering that the primary production of most marine basins is N-limited, the excess release of NH4+ at a temperature rise > 6 °C could enhance water column primary productivity, which may lead to the deterioration of the environmental quality. Climate change effects are expected to be accelerated in areas affected by organic pollution.

scholarly journals Effects of global climate change and organic pollution on nutrient cycling in marine sediments

2015 ◽  
Vol 12 (1) ◽  
pp. 21-49
Author(s):  
C. Sanz-Lázaro ◽  
T. Valdemarsen ◽  
M. Holmer
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Nutrient Cycling ◽  
Water Column ◽  
Temperature Rise ◽  
Nutrient Release ◽  
Organic Pollution ◽  
Coastal Sediments ◽  
Effect Of Temperature ◽  
Climate Change Scenarios

Abstract. Increasing ocean temperature due to climate change is an important anthropogenic driver of ecological change in coastal systems, where sediments play a major role in nutrient cycling. Our ability to predict ecological consequences of climate change is enhanced by simulating real scenarios especially when the interactions among drivers may not be just additive. Based on predicted climate change scenarios, we tested the effect of temperature and organic pollution on nutrient release from coastal sediments to the water column in a mesocosm experiment. PO43− release rates from sediments followed the same trends as organic matter mineralization rates, and increased linearly with temperature and were significantly higher under organic pollution than under non-polluted conditions. NH4+ release only increased significantly when the temperature rise was above 6 °C, and was significantly higher in organic polluted compared to non-polluted sediments. Nutrient release to the water column was only a fraction from the mineralized organic matter, suggesting PO43− retention and NH4+ oxidation in the sediment. Bioturbation and bioirrigation appeared to be key processes responsible of this behaviour. Considering that the primary production of most marine basins is N-limited, the excess release of NH4+ at temperature rise >6 ° could enhance water column primary productivity, which may lead to the deterioration of the environmental quality. Climate change effects are expected to be accelerated in areas affected by organic pollution.

scholarly journals Organic matter cycling in a neotropical reservoir: effects of temperature and experimental conditions

2013 ◽  
Vol 25 (2) ◽  
pp. 192-201 ◽  
Author(s):  
Flávia Bottino ◽  
Maria do Carmo Calijuri ◽  
Kevin Joseph Murphy
Keyword(s):  
Organic Matter ◽  
Repeated Measures ◽  
Field Conditions ◽  
Effect Of Temperature ◽  
Experimental Conditions ◽  
Litter Bag ◽  
Factors Affecting ◽  
Eichhornia Azurea ◽  
Organic Matter Cycling

AIM:This study reports a comparison between decomposition kinetics of detritus derived from two macrophyte species (Polygonum lapathifolium L.: Polygonaceae; Eichhornia azurea (Sw.) Kunth.: Pontederiaceae) growing in a neotropical reservoir (Brazil), under laboratory and field conditions, in order to assess hypotheses on the main differences in factors affecting organic matter cycling, including the effect of temperature. METHODS: Plant and water samples were collected from the reservoir in August 2009. In field incubation mass loss was assessed using a litter bag technique and in the laboratory the decay was followed using a decomposition chamber maintained under controlled conditions (i.e. in the dark, at 15 ºC and 25 ºC). A kinetic model was adopted to explain and compare the organic matter decay, ANOVA (Repeated Measures) testing was used to describe the differences between the treatments and a linear correlation was used to compare in situ and in vitro experiments. RESULTS: The mass decay was faster in natural conditions with rapid release of the labile-soluble portion. The simulated values of mineralization rates of dissolved organic matter and refractory organic matter were rapid in high temperatures (25 ºC). The high Q10 results (mainly for E. azurea), and experimental conditions, and outcomes of ANOVA testing indicate the temperature variation (10 ºC) influence the rates of mass decay. CONCLUSIONS: The results suggested rapid organic matter cycling in warm months (from October to December) supporting the microbial loop. Although the particulate organic matter losses are high in field conditions the results are of the same magnitude in both conditions suggesting an equivalence of the mass decay kinetic.

scholarly journals Litter decomposition rate and soil organic matter quality in a patchwork heathland of southern Norway

SOIL ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 207-216 ◽  
Author(s):  
G. Certini ◽  
L. S. Vestgarden ◽  
C. Forte ◽  
L. Tau Strand
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Litter Decomposition ◽  
Decomposition Rate ◽  
Vegetation Cover ◽  
Soil Drainage ◽  
Organic Matter Quality ◽  
Litter Decomposition Rate ◽  
13C Nuclear Magnetic Resonance ◽  
Southern Norway

Abstract. Norwegian heathland soils, although scant and shallow, are major reservoirs of carbon (C). We aimed at assessing whether vegetation cover and, indirectly, its driving factor soil drainage are good proxies for soil organic matter (SOM) composition and dynamics in a typical heathland area of southern Norway consisting in a patchwork of three different types of vegetation, dominated by Calluna vulgaris (L.) Hull., Molinia caerulea (L.) Moench, or Sphagnum capillifolium (Ehrh.) Hedw. Such vegetation covers were clearly associated to microtopographic differences, which in turn dictated differences in soil moisture regime, Calluna growing in the driest sites, Sphagnum in the wettest, and Molinia in sites with intermediate moisture. Litter decomposition was followed over a period of 1 year by placing litterbags filled with biomass from each dominant species in each type of vegetation cover. The composition of the plant material and SOM was investigated using chemical methods and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Litter decomposition was faster for Molinia and Calluna, irrespective of the vegetation cover of the site where they were placed. Sphagnum litter decomposed very slowly, especially under Calluna, where the soil environment is by far more oxidising than under itself. In terms of SOM quality, Calluna covered areas showed the greatest differences from the others, in particular a much higher contribution from lipids and aliphatic biopolymers, apparently related to biomass composition. Our findings showed that, in the studied environment, litter decomposition rate and SOM composition are actually dependent on vegetation cover and/or soil drainage. On this basis, monitoring changes in the patchwork of vegetation types in boreal heathlands could be a reliable cost-effective way to account for climate-change-induced modifications to SOM and its potential to last.

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