ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

The microfood web of grassland soils responds to a moderate increase in atmospheric CO2 (2005)

Sonnemann, Ilja ; Wolters, Volkmar

Oxford, UK : Blackwell Science Ltd

Global change biology 11 (2005), S. 0

add to mindlist on the mindlist

Details

ISSN: 1365-2486

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography

Notes: The response of the soil microfood web (microflora, nematodes) to a moderate increase in atmospheric CO2 (+20%) was investigated by means of a free air CO2 enrichment experiment. The study was carried out in a seminatural temperate grassland for a period of 4 consecutive years (1 year before fumigation commenced and 3 years with fumigation). Several soil biological parameters showed no change (microbial biomass, bacterial biomass) or decline (microbial respiration) in the first year of elevated CO2 treatment as compared with controls. Each of these parameters were higher than controls, however, after 3 years of treatment. The relative abundance of predaceous nematodes also decreased in year 1 of the experiment, increased in year 2, but decreased again in year 3. In contrast, the relative abundance of root hair feeding nematodes, at first, increased under elevated CO2 and then returned to the initial level again. Increased microbial biomass indicates enhanced C storage in the labile carbon pool of the active microfood web in subsequent years. According to measurements on the amounts of soil extractable C, changes in resource availability seem to be key to the response of the soil microfood web.We found a strong response of bacteria to elevated CO2, while the fungal biomass remained largely unchanged. This contrasts to findings reported in the literature. We hypothesize that this may be because of contrasting effects of different levels of CO2 enrichment on the microbial community (i.e. stimulation of bacteria at moderate levels and stimulation of fungi at high levels of CO2 enrichment). However, various CO2 effects observed in our study are similar in magnitude to those observed in other studies for a much higher level of atmospheric carbon. These include the particular sensitivity of predaceous nematodes and the long-term increase of microbial respiration. Our findings confirm that the potential of terrestrial ecosystems to accumulate additional carbon might be lower than previously thought. Furthermore, CO2-induced changes of temperate grassland ecosystems might emerge much earlier than expected.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2486.2005.00972.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

Response of different decomposer communities to the manipulation of moisture availability: potential effects of changing precipitation patterns (2004)

Taylor, Astrid Rita ; Schröter, Dagmar ; Pflug, Anne ; [et al.]

Oxford, UK : Blackwell Science Ltd

Global change biology 10 (2004), S. 0

add to mindlist on the mindlist

Details

ISSN: 1365-2486

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography

Notes: The potential impacts of changes in precipitation patterns associated with global climate change on the relationship between soil community diversity and litter decomposition were investigated. For a period of ca. 5 months, two decomposer communities in litterbags (1000 and 45 μm mesh size) containing spruce litter were subjected to two irrigation treatments: constant and fluctuating (drying/rewetting) moisture conditions. The latter were expected to induce moisture stress on the decomposer communities. The two mesh sizes were used to exclude different faunal components from the decomposer communities. The 1000 μm mesh excluded only the macrofauna, whereas the 45 μm mesh excluded both the macro- and mesofauna. In the short-term perspective of the present study, mesofauna abundance showed no response to imposed fluctuating moisture conditions. Irrespective of the presence of mesofauna, mass loss, microbial biomass and the control mechanisms, regulating carbon mineralization appeared unaffected by fluctuating moisture conditions. The reduction in the functional/structural diversity of the decomposer communities in the 45 μm litterbags resulted in strongly increased Nematoda abundance but it did not alter the response of Nematoda to fluctuating moisture conditions. Processes in the nitrogen (N)-cycle and mass loss were sensitive indicators of changes in the structural and functional complexity of decomposer communities. However, a negative effect of fluctuating moisture conditions on extractable N was coupled to the presence of mesofauna. Extremes in rainfall patterns, generated by climate change, may have a negative impact on the availability of nutrients, particularly N, for plants. This effect could be amplified by an additional impoverishment in the structural and functional complexity of the respective decomposer communities.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2486.2004.00801.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Resource allocation in Tomocerus flavescens (Insecta, Collembola): a study with C-14-labelled food (1985)

Wolters, Volkmar

Springer

Oecologia 65 (1985), S. 229-235

add to mindlist on the mindlist

Details

ISSN: 1432-1939

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Individuals of the collembolan species Tomocerus flavescens from a beech wood on limestone near Göttingen (West Germany) were fed with C-14-labelled algae in the laboratory. On an average, T. flavescens exchanged almost all of its endogenous carbon after 3.4 moults. In periods of starvation the interval between two ecdyses increased from 5.2 to 6.1 days (17°C). The assimilation efficiency was determined in three independent ways (carbon use of different algal components; A=C-FU; C=P+R+FU, A=P+R): it ranged from 0.34 to 0.40 (converted to energy values 0.30 to 0.45). It could be raised in phases of high mobility and in periods of food shortage by lowering the gut passage rate. The decrease in feeding activity (demonstrated by gut contents analyses) in case of a detoriation of the food quality and the food availability can be partly compensated in this way. For individuals which did not reproduce, the ratio of production to assimilation was 0.24 (converted to energy values 0.31). T. flavescens showed an increased body growth in connection with reaching sexual maturity. Specific demands of nutritive substances in periods of physiological changes could possibly be compensated by a more efficient resource use as well as by differences in resource allocation. The studied population of T. flavescens was compared both with that of a Danish beech forest and general data from the literature. The production of few eggs rich in energy, the high weight of newly hatched individuals, the high growth as well as the storage of carbon connected with egg production, the comparatively low respiration metabolism and the high amount of energy invested in search for food have to be regarded as an adaptation to the habitat. According to conservative estimates climbing individuals of this species consume 0.83 g of the algal dry mass growing on one beech tree during one summer. T. flavescens mainly uses the ethanol-soluble components of the algae.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00379222

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Resource allocation of beech seedlings (Fagus sylvatica L.) —relationship to earthworm activity and soil conditions (1991)

Wolters, Volkmar ; Stickan, Walter

Springer

Oecologia 88 (1991), S. 125-131

add to mindlist on the mindlist

Details

ISSN: 1432-1939

Keywords: Octolasion lacteum ; Fagus sylvatica ; Rendzina ; Acid brown earth ; CO2 assimilation ; Transpiration ; Resource allocation ; Biomass production ; N incorporation

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The physiological activity and C and N allocation of beech seedlings planted in two different beech forest soils (acid brown earth, rendzina) were studied over 80 days. One adult earthworm Octolasion lacteum (Örley) was placed in half of the containers. Transpiration, CO2, assimilation, chlorophyll synthesis and N incorporation were higher in the acid brown earth than in the rendzina. Fine root production was also higher in the acid brown earth. Production of stems and total N incorporation were higher in the O. lacteum treatments than in the controls. Burrowing activity of O. lacteum did not affect total root production but stimulated the transfer of C and N towards aboveground parts of the plants and shifted the large root to fine root ratio towards large roots. O. lacteum effects were similar in both soils. It is concluded that endogeic earthworms significantly affect resource allocation patterns of beech seedlings over a wide range of soils. This effect can be partly explained by an increased availability of N in soils worked by earth-worms.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00328412

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Earthworm effects on the use of C sources by microorganisms: Non-linear response to temperature alteration (1995)

Wolters, Volkmar ; Ekschmitt, Klemens

Springer

Biology and fertility of soils 19 (1995), S. 109-114

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Aporrectodea caliginosa ; Soil microflora C mineralization ; Beech litter ; Temperature ; Climate change

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract A microcosm was used to study the effect of the endogeic earthworm Aporrectodea caliginosa (Savigny) on the use of C by microorganisms in a calcareous beech forest soil and its dependence on temperature (5–25%C). Inclusion of 14C-labelled beech leaf litter made it possible to differentiate between C use by litter-colonizing microflora and by autochthonous soil microflora. The effect of temperature on the soil microbial biomass 12C was confined to a significant increase at 15 and 20°C. The size of the 14C-labelled microbial biomass, in contrast, was positively correlated with temperature. The 12C mineralization increased exponentially with temperature. The relationship between 14C mineralization and temperature, in contrast, followed a logistic curve. Significant main effects of A. caliginosa were confined to 12C mineralization, reflecting an increase in 12CO2−C production in the earthworm treatments. The earthworm effects on 12CO2−C production and on 14C incorporation of the microflora were not linear. The effect of A. caliginosa on 12CO2−C production was most pronouned at intermediate temperatures. It is concluded that temperature alterations affect the microbial use of different C sources in different ways and that the temperature effects can be significantly modified by endogeic earthworms.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00336145

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Examination of microbial biomass in beech forest moder profiles (1995)

Stockfisch, Nicol ; Joergensen, Rainer G. ; Wolters, Volkmar ; [et al.]

Springer

Biology and fertility of soils 19 (1995), S. 209-214

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Fumigation extraction ; Microbial biomass C ATP ; Substrate-induced respiration ; Soil organic matter ; Decomposition

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Microbial biomass C, ATP, and substrate-induced respiration were measured in the organic layers and the mineral A horizon of three beech forest soils with moder humus differing in Ca and Mg supply. Analyses of variance showed that horizon-specific differences explained most of the variance in the three microbial parameters. All three were significantly interrelated, with Spearman rank correlation coefficients of between 0.86 and 0.93. However, differences in the decline of these parameters with depth led to horizon-specific differences in their ratios. Thus, the ratios were not markedly interrelated. The mean ATP: microbial C ratio was 5.2 μmol ATP g-1 C in the L 2 layer, 19.5 in the F layers, and 9.6 in the H and A horizons. The ratio of substrate-induced respiration to microbial C varied between 39.3 and 82.2 O2h-1 g-1 C in the F1 layers and between 5.3 and 32.1 μl in the other layers. It is concluded that the use of different parameters can help to analyze both horizonand site-specific differences in microbial performance.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00336161

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Electronic Resource

Microbial biomass phosphorus in soils of beech (Fagus sylvatica L.) forests (1995)

Joergensen, Rainer G. ; Kübler, Helga ; Meyer, Brunk ; [et al.]

Springer

Biology and fertility of soils 19 (1995), S. 215-219

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Microbial biomass ; Acidification ; Beech forest ; Soil organic C ; Total P ; Fagus sylvatica

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Thirty-eight soils from forest sites in central Germany dominated by beech trees (Fagus sylvatica L.) were sampled to a depth of about 10 cm after careful removal of the overlying organic layers. Microbial biomass P was estimated by the fumigation — extraction method, measuring the increase in NaHCO3-extractable phosphate. The size of the microbial P pool varied between 17.7 and 174.3 μg P g-1 soil and was on average more than seven times larger than NaHCO3-extractable phosphate. Microbial P was positively correlated with soil organic C and total P, reflecting the importance of soil organic matter as a P source. The mean microbial P concentration was 13.1% of total P, varying in most soils between 6 and 18. Microbial P and microbial C were significantly correlated with each other and had a mean ratio of 14.3. A wide (5.1–26.3) microbial C: P ratio indicates that there is no simple relatinship between these two parameters. The microbial C: P ratio showed strong and positive correlations with soil pH and cation exchange capacity.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00336162

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

8

Electronic Resource

Effects of the nematofauna on microbial energy and matter transformation rates in European grassland soils (1999)

Ekschmitt, Klemens ; Bakonyi, Gabor ; Bongers, Marina ; [et al.]

Springer

Plant and soil 212 (1999), S. 45-61

add to mindlist on the mindlist

Details

ISSN: 1573-5036

Keywords: grasslands ; soil microclimate ; nematodes ; microflora ; interactions ; metabolic activity ; soil nitrogen

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The effect of the nematofauna on the microbiology and soil nitrogen status was studied in 6 major European grassland types (Northern tundra (Abisko, Sweden), Atlantic heath (Otterburn, UK), wet grassland (Wageningen, Netherlands), semi-natural temperate grassland (Linden, Germany), East European steppe (Pusztaszer, Hungary) and Mediterranean garigue (Mt. Vermion, Greece). To extend the range of temperature and humidity experienced locally during the investigation period, soil microclimates were manipulated, and at each site 14 plots were established representing selected combinations of 6 temperature and 6 moisture levels. The investigated soils divided into two groups: mineral grassland soils that were precipitation fed (garigue, wet grassland, seminatural grassland, steppe), and wet organic soils that were groundwater fed (heath, tundra). Effects of the nematofauna on the microflora were found in the mineral soils, where correlations among nematode metabolic activity as calculated from a metabolic model, and microbial activity parameters as indicated by Biolog and ergosterol measurements, were significantly positive. Correlations with bacterial activity were stronger and more consistent. Microbial parameters, in turn, were significantly correlated with the size of the soil nitrogen pools NH4, NO3, and Norganic. Furthermore, model results suggested that there were remarkable direct effects of nematodes on soil nitrogen status. Calculated monthly nematode excretion contributed temporarily up to 27% of soluble soil nitrogen, depending on the site and the microclimate. No significant correlation among nematodes and microbial parameters, or nitrogen pools, were found in the wet organic soils. The data show that the nematofauna can under favourable conditions affect soil nitrogen status in mineral grassland soils both directly by excretion of N, and indirectly by regulating microbial activity. This suggests that the differences in nitrogen availability observed in such natural grasslands partly reflect differences in the activity of their indigenous nematofauna.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1004682620283

Permalink