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Considerable Quantities (considerable + quantity)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Carbon bio-sequestration within the phytoliths of economic bamboo species

GLOBAL CHANGE BIOLOGY, Issue 10 2010
JEFFREY PARR
Abstract The rates of carbon bio-sequestration within silica phytoliths of the leaf litter of 10 economically important bamboo species indicates that (a) there is considerable variation in the content of carbon occluded within the phytoliths (PhytOC) of the leaves between different bamboo species, (b) this variation does not appear to be directly related to the quantity of silica in the plant but rather the efficiency of carbon encapsulation by the silica. The PhytOC content of the species under the experimental conditions ranged from 1.6% to 4% of the leaf silica weight. The potential phytolith carbon bio-sequestration rates in the leaf-litter component for the bamboos ranged up to 0.7 tonnes of carbon dioxide (CO2) equivalents (t-e-CO2) ha,1 yr,1 for these species. Assuming a median phytolith carbon bio-sequestration yield of 0.36 t-e-CO2 ha,1 yr,1, the global potential for bio-sequestration via phytolith carbon (from bamboo and/or other similar grass crops) is estimated to be ,1.5 billion t-e-CO2 yr,1, equivalent to 11% of the current increase in atmospheric CO2. The data indicate that the management of vegetation such as bamboo forests to maximize the production of PhytOC has the potential to result in considerable quantities of securely bio-sequestered carbon. [source]

Water resources in mountain regions: a methodological approach to assess the water balance in a highland-lowland-system

HYDROLOGICAL PROCESSES, Issue 5 2007
Rolf Weingartner
Abstract Mountains and highlands are typically areas that provide considerable quantities of water, the latter being an important resource for the lowlands. These run-off quantities remain discernible in the superior-scale river systems and significantly contribute to the global water resources. Therefore, mountain regions ought to be given specific consideration with regard to management endeavours. Although well known in principle, details of water resources originating from mountains remain under discussion. A new approach has been introduced, which depicts the water balance of Switzerland in a spatially distributed manner, based on catchments of about 150 km2. The main feature of this approach is the areal precipitation, which is calculated using run-off, evaporation and storage change of glaciers, instead of being derived from gauged precipitation values. This methodology was selected because measurement and regionalization of precipitation remain subject to large uncertainties in mountainous areas. Subsequently, the view is widened to the European Alps, which, as compared with the surrounding lowlands, contribute considerably higher annual discharge, especially in the summer months. Finally, the focus is put on the hydrological significance of mountains in general. In dry regions, mountains, in particular, are indispensable contributors to the water resources downstream. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Sap properties and alk(en)ylresorcinol concentrations in Australian-grown mangoes

ANNALS OF APPLIED BIOLOGY, Issue 3 2009
M.K. Hassan
Abstract Physical and chemical properties of sap and sap concentrations of constitutive alk(en)ylresorcinols were determined in several varieties of mango grown in different locations in Queensland, Australia, over two consecutive cropping seasons. Sap weight from individual fruit, sap pH, percentage of non-aqueous sap and concentrations of constitutive alk(en)ylresorcinols (5- n -heptadecenylresorcinol and 5- n -pentadecylresorcinol) in sap varied significantly among the varieties. ,Calypso', ,Keitt', ,Kensington Pride' and ,Celebration' had the greatest proportion of non-aqueous sap, whereas ,Nam Doc Mai' had the least. The highest concentrations of 5- n -heptadecenylresorcinol were found in the sap of ,Kensington Pride', and the lowest in ,Honey Gold' and ,Nam Doc Mai'. Highest concentrations of 5- n -pentadecylresorcinol were found in sap of ,Calypso' and ,Celebration', and the lowest levels were in ,Honey Gold' and ,Nam Doc Mai'. There was a direct relationship between the percentage of non-aqueous sap and the concentrations of alk(en)ylresorcinols (r2 = 0.77 for 5- n -heptadecenylresorcinol, and r2 = 0.87 for 5- n -pentadecylresorcinol). The alk(en)ylresorcinols were distributed mainly in the upper non-aqueous phase of ,Kensington Pride' sap. Growing location also had significant effects on the composition of mango sap but the effects appeared to be related to differences in maturity. Sap removal is necessary to prevent sapburn, but considerable quantities of alk(en)ylresorcinols that assist in protecting the harvested fruit from anthracnose disease are also removed. [source]

Coarse woody debris in Australian forest ecosystems: A review

AUSTRAL ECOLOGY, Issue 8 2005
GEMMA WOLDENDORP
Abstract Coarse woody debris (CWD) is the standing and fallen dead wood in a forest and serves an important role in ecosystem functioning. There have been several studies that include estimates of CWD in Australian forests but little synthesis of these results. This paper presents findings from a literature review of CWD and fine litter quantities. Estimates of forest-floor CWD, snags and litter from the literature are presented for woodland, rainforest, open forest and tall open forest, pine plantation and native hardwood plantation. Mean mass of forest floor CWD in Australian native forests ranged from 19 t ha,1 in woodland to 134 t ha,1 in tall open forest. These values were generally within the range of those observed for similar ecosystems in other parts of the world. Quantities in tall open forests were found to be considerably higher than those observed for hardwood forests in North America, and more similar to the amounts reported for coniferous forests with large sized trees on the west coast of the USA and Canada. Mean proportion of total above-ground biomass as forest floor CWD was approximately 18% in open forests, 16% in tall open forests, 13% in rainforests, and 4% in eucalypt plantations. CWD can be high in exotic pine plantations when there are considerable quantities of residue from previous native forest stands. Mean snag biomass in Australian forests was generally lower than the US mean for snags in conifer forests and higher than hardwood forest. These results are of value for studies of carbon and nutrient stocks and dynamics, habitat values and fire hazards. [source]