ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • CO2  (4)
  • Elevated CO2  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Regenerating temperate forest mesocosms in elevated CO2: belowground growth and nitrogen cycling (1997)
    Springer
    Oecologia 113 (1997), S. 115-125 
    Details
    ISSN: 1432-1939
    Keywords: Key wordsBetula ; CO2 ; Mycorrhizal fungi ; Nitrogen ; Pool dilution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The response of temperate forest ecosystems to elevated atmospheric CO2 concentrations is important because these ecosystems represent a significant component of the global carbon cycle. Two important but not well understood processes which elevated CO2 may substantially alter in these systems are regeneration and nitrogen cycling. If elevated CO2 leads to changes in species composition in regenerating forest communities then the structure and function of these ecosystems may be affected. In most temperate forests, nitrogen appears to be a limiting nutrient. If elevated CO2 leads to reductions in nitrogen cycling through increased sequestration of nitrogen in plant biomass or reductions in mineralization rates, long-term forest productivity may be constrained. To study these processes, we established mesocosms of regenerating forest communities in controlled environments maintained at either ambient (375 ppm) or elevated (700 ppm) CO2 concentrations. Mesocosms were constructed from intact monoliths of organic forest soil. We maintained these mesocosms for 2 years without any external inputs of nitrogen and allowed the plants naturally present as seeds and rhizomes to regenerate. We used 15N pool dilution techniques to quantify nitrogen fluxes within the mesocosms at the end of the 2 years. Elevated atmospheric CO2 concentration significantly affected a number of plant and soil processes in the experimental regenerating forest mesocosms. These changes included increases in total plant biomass production, plant C/N ratios, ectomycorrhizal colonization of tree fine roots, changes in tree fine root architecture, and decreases in plant NH4 + uptake rates, gross NH4 + mineralization rates, and gross NH4 + consumption rates. In addition, there was a shift in the relative biomass contribution of the two dominant regenerating tree species; the proportion of total biomass contributed by white birch (Betula papyrifera) decreased and the proportion of total biomass contributed by yellow birch (B. alleghaniensis) increased. However, elevated CO2 had no significant effect on the total amount of nitrogen in plant and soil microbial biomass. In this study we observed a suite of effects due to elevated CO2, some of which could lead to increases in potential long term growth responses to elevated CO2, other to decreases. The reduced plant NH4 + uptake rates we observed are consistent with reduced NH4 + availability due to reduced gross mineralization rates. Reduced NH4 + mineralization rates are consistent with the increases in C/N ratios we observed for leaf and fine root material. Together, these data suggest the positive increases in plant root architectural parameters and mycorrhizal colonization may not be as important as the potential negative effects of reduced nitrogen availability through decreased decomposition rates in a future atmosphere with elevated CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050359
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effect of elevated CO2 on interactions betwe en the western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae) and the common milkweed, Asclepias syriaca (1997)
    Springer
    Oecologia 109 (1997), S. 286-290 
    Details
    ISSN: 1432-1939
    Keywords: Key wordsAsclepias syriaca ; Elevated CO2 ; Frankliniella occidentalis ; Thrips ; Herbivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We measured the effect of elevated CO2 on populations of the western flower thrips, Frankliniella occidentalis and on the amount of leaf damage inflicted by the thrips to one of its host plants, the common milkweed, Asclepias syriaca. Plants grown at elevated CO2 had significantly greater aboveground biomass and C:N ratios, and significantly reduced percentage nitrogen. The number of thrips per plant was not affected by CO2 treatment, but the density of thrips (numbers per gram aboveground biomass), was significantly reduced at high CO2. Consumption by thrips, expressed as the amount of damaged leaf area per capita, was significantly greater at high CO2, and the amount of leaf area damaged by thrips was increased by 33%. However overall leaf area at elevated CO2 increased by 62%, more than compensating for the increase in thrips consumption. The net outcome was that plants at elevated CO2 had 3.6 times more undamaged leaf area available for photosynthesis than plants at ambient CO2, even though they had only 1.6 times the overall amount of leaf area. This study highlights the need for measuring the effects of herbivory at the whole-plant level and also the importance of taking herbivory into account when predicting plant responses to elevated CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050085
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Elevated CO2 enhances resprouting of a tropical savanna tree (2000)
    Springer
    Oecologia 123 (2000), S. 312-317 
    Details
    ISSN: 1432-1939
    Keywords: Key words Savanna ; Cerrado ; Fire ; Elevated CO2 ; Carbohydrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The savannas (cerrado) of south-central Brazil are currently subjected to frequent anthropogenic burning, causing widespread reduction in tree density. Increasing concentrations of atmospheric CO2 could reduce the impact of such frequent burning by increasing the availability of nonstructural carbohydrate, which is necessary for resprouting. We tested the hypotheses that elevated CO2 stimulates resprouting and accelerates replenishment of carbohydrate reserves. Using a factorial experiment, seedlings of a common Brazilian savanna tree, Keilmeyera coriacea, were grown at 350 ppm and 700 ppm CO2 and at two nutrient levels. To simulate burning, the plants were either clipped at 15 weeks or were left unclipped. Among unclipped plants, CO2 and nutrients both stimulated growth, with no significant interaction between nutrient and CO2 effects. Among clipped plants, both CO2 and nutrients stimulated resprouting. However, there was a strong interaction between CO2 and nutrient effects, with CO2 having a significant effect only in the presence of high nutrient availability. Under elevated CO2, carbohydrate reserves remained at higher levels following clipping. Root total nonstructural carbohydrate remained above 36% in all treatments, so carbohydrate reserves did not limit regrowth. These results indicate that under elevated CO2 this species may be better able to endure the high frequency of anthropogenic burning in the Brazilian savannas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420051017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Inter- and intra-generic differences in growth, reproduction, and fitness of nine herbaceous annual species grown in elevated CO2 environments (1995)
    Springer
    Oecologia 104 (1995), S. 454-466 
    Details
    ISSN: 1432-1939
    Keywords: Cassia ; Ipomoea ; Polygonum ; CO2 ; Reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In assessing the capacity of plants to adapt to rapidly changing global climate, we must elucidate the impacts of elevated carbon dioxide on reproduction, fitness and evolution. We investigated how elevated CO2 influenced reproduction and growth of plants exhibiting a range of floral morphologies, the implications of shifts in allocation for fitness in these species, and whether related taxa would show similar patterns of response. Three herbaceous, annual species each of the genera Polygonum, Ipomoea, and Cassia were grown under 350 or 700 ppm CO2. Vegetative growth and reproductive output were measured non-destructively throughout the full life span, and vegetative biomass was quantified for a subsample of plants in a harvest at first flowering. Viability and germination studies of seed progeny were conducted to characterize fitness precisely. Early vegetative growth was often enhanced in high-CO2 grown plants of Polygonum and Cassia (but not Ipomoea). However, early vegetative growth was not a strong predictor of subsequent reproduction. Phenology and production of floral buds, flowers, unripe and abscised fruits differed between CO2 treatments, and genera differed in their reproductive and fitness responses to elevated CO2. Polygonum and Cassia species showed accelerated, enhanced reproduction, while Ipomoea species generally declined in reproductive output in elevated CO2. Seed “quality” and fitness (in terms of viability and percentage germination) were not always directly correlated with quantity produced, indicating that output alone may not reliably indicate fitness or evolutionary potential. Species within genera typically responded more consistently to CO2 than unrelated species. Cluster analyses were performed separately on suites of vegetative and reproductive characters. Some species assorted within genera when these reproductive responses were considered, but vegetative responses did not reflect taxonomic affinity in these plants. Congeners may respond similarly in terms of reproductive output under global change, but fitness and prognoses of population persistence and evolutionary performance can be inferred only rarely from examination of vegetative characters alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341343
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Elevated CO2 alters deployment of roots in “small” growth containers (1993)
    Springer
    Oecologia 94 (1993), S. 558-564 
    Details
    ISSN: 1432-1939
    Keywords: CO2 ; Nutrients ; Pot size ; Root deployment ; Root restriction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previously we examined how limited rooting space and nutrient supply influenced plant growth under elevated atmospheric CO2 concentrations (McConnaughay et al. 1993). We demonstrated that plant growth enhancement under elevated CO2 was influenced more by the concentration of nutrients added to growth containers than to either the total nutrient content per pot or amount or the dimensions of available rooting space. To gain insight into how elevated CO2 atmospheres affect how plants utilize available belowground space when rooting space and nutrient supply are limited we measured the deployment of roots within pots through time. Contrary to aboveground responses, patterns of belowground deployment were most strongly influenced by elevated CO2 in pots of different volume and shape. Further, elevated CO2 conditions interacted differently with limited belowground space for the two species we studied,Abutilon theophrasti, a C3 dicot with a deep taproot, andSetaria faberii, a C4 monocot with a shallow fibrous root system. ForSetaria, elevated CO2 increased the size of the largest region of low root density at the pot surface in larger rooting volumes independent of nutrient content, thereby decreasing their efficiency of deployment. ForAbutilon, plants responded to elevated CO2 concentrations by equalizing the pattern of deployment in all the pots. Nutrient concentration, and not pot size or shape, greatly influenced the density of root growth. Root densities forAbutilon andSetaria were similar to those observed in field conditions, for annual dicots and monocots respectively, suggesting that studies using pots may successfully mimic natural conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566972
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Limitations to CO2-induced growth enhancement in pot studies (1993)
    Springer
    Oecologia 94 (1993), S. 550-557 
    Details
    ISSN: 1432-1939
    Keywords: Elevated CO2 ; Growth enhancement ; Nutrients ; Pot size ; Root restriction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recently, it has been suggested that small pots may reduce or eliminate plant responses to enriched CO2 atmospheres due to root restriction. While smaller pot volumes provide less physical space available for root growth, they also provide less nutrients. Reduced nutrient availability alone may reduce growth enhancement under elevated CO2. To investigate the relative importance of limited physical rooting space separate from and in conjunction with soil nutrients, we grew plants at ambient and double-ambient CO2 levels in growth containers of varied volume, shape, nutrient concentration, and total nutrient content. Two species (Abutilon theophrasti, a C3 dicot with a deep tap root andSetaria faberii, a C4 monocot with a shallow diffuse root system) were selected for their contrasting physiology and root architecture. Shoot demography was determined weekly and biomass was determined after eight and ten weeks of growth. Increasing total nutrients, either by increasing nutrient concentration or by increasing pot size, increased plant growth. Further, increasing pot size while maintaining equal total nutrients per pot resulted in increased total biomass for both species. CO2-induced growth and reproductive yield enhancements were greatest in pots with high nutrient concentrations, regardless of total nutrient content or pot size, and were also mediated by the shape of the pot. CO2-induced growth and reproductive yield enhancements were unaffected by pot size (growth) or were greater in small pots (reproductive yield), regardless of total nutrient content, contrary to predictions based on earlier studies. These results suggest that several aspects of growth conditions within pots may influence the CO2 responses of plants; pot size, pot shape, the concentration and total amount of nutrient additions to pots may lead to over-or underestimates of the CO2 responses of real-world plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566971
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Elevated CO2 differentially alters the responses of coocurring birch and maple seedlings to a moisture gradient (1992)
    Springer
    Oecologia 90 (1992), S. 300-304 
    Details
    ISSN: 1432-1939
    Keywords: Elevated CO2 ; Moisture gradient ; Biomass ; Niche breadth ; Gray birch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To determine the effects of elevated CO2 and soil moisture status on growth and niche characteristics of birch and maple seedlings, gray birch (Betula populifolia) and red maple (Acer rubrum) were experimentally raised along a soil moisture gradient ranging from extreme drought to flooded conditions at both ambient and elevated atmospheric CO2 levels. The magnitude of growth enhancement due to CO2 was largely contingent on soil moisture conditions, but differently so for maple than for birch seedlings. Red maple showed greatest CO2 enhancements under moderately moist soil conditions, whereas gray birch showed greatest enhancements under moderately dry soil conditions. Additionally, CO2 had a relatively greater ameliorating effect in flooded conditions for red maple than for gray birch, whereas the reverse pattern was true for these species under extreme drought conditions. For both species, elevated CO2 resulted in a reduction in niche breadths on the moisture gradient; 5% for gray birch and 23% for red maple. Species niche overlap (proportional overall) was also lower at elevated CO2 (0.98 to: 0.88: 11%). This study highlights the utility of of experiments crossing CO2 levels with gradients of other resources as effective tools for elucidating the potential consequences of elevated CO2 on species distributions and potential interactions in natural communities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317191
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Belowground positive and negative feedbacks on CO2 growth enhancement (1995)
    Springer
    Plant and soil 187 (1995), S. 119-131 
    Details
    ISSN: 1573-5036
    Keywords: C/N ; CO2 ; feedback ; mycorrhizae ; net primary productivity ; root architecture ; soil organic matter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In this paper we present a conceptual model of integrated plant-soil interactions which illustrates the importance of identifying the primary belowground feedbacks, both positive and negative, which can simultaneously affect plant growth responses to elevated CO2. The primary negative feedbacks share the common feature of reducing the amount of nutrients available to plants. These negative feedbacks include increased litter C/N ratios, and therefore reduced mineralization rates, increased immobilization of available nutrients by a larger soil microbial pool, and increased storage of nutrients in plant biomass and detritus due to increases in net primary productivity (NPP). Most of the primary positive feedbacks share the common feature of being plant mediated feedbacks, the only exception being Zak et al.'s hypothesis that increased microbial biomass will be accompanied by increased mineralization rates. Plant nutrient uptake may be increased through alterations in root architecture, physiology, or mycorrhizal symbioses. Further, the increased C/N ratios of plant tissue mean that a given level of NPP can be achieved with a smaller supply of nitrogen. Identification of the net plant-soil feedbacks to enhanced productivity with elevated CO2 are a critical first step for any ecosystem. It is necessary, however, that we first identify how universally applicable the results are from one study of one ecosystem before ecosystem models incorporate this information. The effect of elevated CO2 on plant growth (including NPP, tissue quality, root architecture, mycorrhizal symbioses) can vary greatly for different species and environmental conditions. Therefore it is reasonable to expect that different ecosystems will show different patterns of interacting positive and negative feedbacks within the plant-soil system. This inter-ecosystem variability in the potential for long-term growth responses to rising CO2 levels implies that we need to parameterize mechanistic models of the impact of elevated CO2 on ecosystem productivity using a detailed understanding of each ecosystem of interest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00017085
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...