997 resultados para Abylopsis spp., biomass as carbon


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In recent years, concern has arisen over the effects of increasing carbon dioxide (CO2) in the earth's atmosphere due to the burning of fossil fuels. One way to mitigate increase in atmospheric CO2 concentration and climate change is carbon sequestration to forest vegeta-tion through photosynthesis. Comparable regional scale estimates for the carbon balance of forests are therefore needed for scientific and political purposes. The aim of the present dissertation was to improve methods for quantifying and verifying inventory-based carbon pool estimates of the boreal forests in the mineral soils. Ongoing forest inventories provide a data based on statistically sounded sampling for estimating the level of carbon stocks and stock changes, but improved modelling tools and comparison of methods are still needed. In this dissertation, the entire inventory-based large-scale forest carbon stock assessment method was presented together with some separate methods for enhancing and comparing it. The enhancement methods presented here include ways to quantify the biomass of understorey vegetation as well as to estimate the litter production of needles and branches. In addition, the optical remote sensing method illustrated in this dis-sertation can be used to compare with independent data. The forest inventory-based large-scale carbon stock assessment method demonstrated here provided reliable carbon estimates when compared with independent data. Future ac-tivity to improve the accuracy of this method could consist of reducing the uncertainties regarding belowground biomass and litter production as well as the soil compartment. The methods developed will serve the needs for UNFCCC reporting and the reporting under the Kyoto Protocol. This method is principally intended for analysts or planners interested in quantifying carbon over extensive forest areas.

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Although there have been a number of studies on aquatic conditions and the flora and fauna of Lake Titicaca over many decades, most of this work has been centred on the offshore regions of the main lake. Water quality there has been degrading and abundant growth of Lemna spp. has been developing. Lemna spp., commonly called floating duck-weed or ‘lenteja de agua’ in Puno, occurs perennially in most parts of the inner Puno Bay shore-line. In this article, the authors compare water quality changes over recent decades in shore-line regions of Inner Puno Bay and their possible effects on the distribution, abundance and biomass of Lemna spp..

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Questions: Grasslands are usually neglected as potential carbon stocks, partially due to the lack of studies on biomass and carbon dynamics in tropical grasslands. What is the importance of Brazilian tropical wet grasslands as carbon sinks? Does fire frequency and season affect biomass and carbon allocation in Brazilian wet grasslands? Location: Wet grasslands, tropical savanna, Jalapão, Tocantins, northern Brazil. Methods: We determined biomass above- and below-ground, estimated carbon stocks in biennially burned plots (B2) and plots excluded from fire for 4 yr (B4). Moreover, we determined biomass in both rainy and dry seasons. Samples were 0.25 m × 0.25 m × 0.2 m (eight samples per treatment, applying a nested design, total of 48 samples). The biomass was classified in above-ground graminoids, forbs and dead matter, and below-ground roots and other below-ground organs. We used ANOVA to compare variables between treatments and seasons. Results: More than 40% of the total biomass and carbon stocks were located below-ground, mostly in roots. A high proportion of dead biomass (B4) was found in the above-ground material, probably due to low decomposition rates and consequent accumulation over the years. Although these grasslands do not experience water stress, we found significant evidence of resource re-allocation from below-ground organs to the above-ground biomass in the rainy season. Conclusions: We found more dead biomass in the rainy season, probably due to low decomposition rates, which can increase fire risk in these grasslands during the following dry season. These tropical wet grasslands stored high amounts of carbon (621 to 716 g C.m-2), mostly in the roots. Thus, policymakers should consider tropical grasslands as potential carbon stocks, since they are one of the most threatened and unprotected ecosystems in Brazil. © 2012 International Association for Vegetation Science.

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The aim of this study was to estimate the stock of biomass and organic carbon in a montane mixed shade forest located near General Carneiro, PR. 20 plots of 12 m x 12 m were installed, in which all trees with a CBH (Circumference at Breast Height) >= 31.4 cm were felled. From these the following information was obtained: total height, commercial height (agreed as being the morphological inversion point in the natural forest and the height of the first live branch), CBH, identification and collection of herbarium specimens. For the quantification of biomass in the understory and roots, three subunits 1 m x 1 m in each sampling unit were installed (12 m x 12 m) arranged in the lower left corner, center and diagonal upper right corner. To quantify accumulated litter at random, eight samples in each sampling unit were collected (12 m x 12 m), using a metal device measuring 0.25 m x 0.25 m. The montane mixed shade forest has more than 85% of its total biomass and total organic carbon stored in above ground plant structures. The total stock of organic carbon found in this study (104.7 Mg ha(-1)) demonstrates the importance of maintaining and preserving natural ecosystems as a way of maintaining this stock of organic carbon fixed in plant biomass.

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Madagascar is currently developing a policy and strategies to enhance the sustainable management of its natural resources, encouraged by United Nations Framework Convention on Climate Change (UNFCCC) and REDD. To set up a sustainable financing scheme methodologies have to be provided that estimate, prevent and mitigate leakage, develop national and regional baselines, and estimate carbon benefits. With this research study this challenge was tried to be addressed by analysing a lowland rainforest in the Analanjirofo region in the district of Soanierana Ivongo, North East of Madagascar. For two distinguished forest degradation stages: “low degraded forest” and “degraded forest” aboveground biomass and carbon stock was assessed. The corresponding rates of carbon within those two classes were calculated and linked to a multi-temporal set of SPOT satellite data acquired in 1991, 2004 and 2009. Deforestation and particularly degradation and the related carbon stock developments were analysed. With the assessed data for the 3 years 1991, 2004 and 2009 it was possible to model a baseline and to develop a forest prediction for 2020 for Analanjirofo region in the district of Soanierana Ivongo. These results, developed applying robust methods, may provide important spatial information regarding the priorities in planning and implementation of future REDD+ activities in the area.

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We evaluated the role of microzooplankton (sensu latto, grazers <500 µm) in determining the fate of phytoplankton production (PP) along a glacier-to-open sea transect in the Greenland subarctic fjord, Godthabfjord. Based on the distribution of size fractionated chlorophyll a (chl a) concentrations we established 4 zones: (1) Fyllas Bank, characterized by deep chl a maxima (ca. 30 to 40 m) consisting of large cells, (2) the mouth and main branch of the fjord, where phytoplankton was relatively homogeneously distributed in the upper 30 m layer, (3) inner waters influenced by glacial melt water and upwelling, with high chl a concentrations (up to 12 µg/l) in the >10 µm fraction within a narrow (2 m) subsurface layer, and (4) the Kapisigdlit branch of the fjord, ice-free, and characterized with a thick and deep chl a maximum layer. Overall, microzooplankton grazing impact on primary production was variable and seldom significant in the Fyllas Bank and mouth of the fjord, quite intensive (up to >100% potential PP consumed daily) in the middle part of the main and Kapisigdlit branches of the fjord, and rather low and unable to control the fast growing phytoplankton population inhabiting the nutrient rich waters in the upwelling area in the vicinity of the glacier. Most of the grazing impact was on the <10 µm phytoplankton fraction, and the major grazers of the system seem to be >20 µm microzooplankton, as deducted from additional dilution experiments removing this size fraction. Overall, little or no export of phytoplankton out of the fjord to the Fyllas Bank can be determined from our data.

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Anthropogenic impact on biomass of coastal plankton communities caused by submerged disposal of urban sewage waters (dumping) was studied. Observations were carried out in August-September of 2002-2004 in the Mamala Bay (Oahu Island, Hawaii Islands) using satellite and straight sea measurements. An analysis of variability of integral indicators of the water column determined on the basis of on-board measurements allowed us to divide them into two groups: elements most sensitive to pollution (heterotrophic bacteria (H-Bact), phototrophic cyanobacteria Synechococcus spp. (SYN), and chlorophyll a (CHLa)) and elements that manifested episodic positive dependence on inflow of polluted waters (heterotrophic unicellular eukaryotes, small unicellular algae, phototrophic green bacteria Prochlorococcus spp., as well as total biomass of microplankton). It was shown that submerged waste water disposal in the region of the diffuser of the dumping device led to insignificant (aver. 1.2-1.4 times) local increase in integral biomass of H-Bact, SYN, and in concentration of CHLa. Similar but sharper (aver. 1.5-2.1 times) increase in these parameters was found in water layers with maximal biomasses. Possible pathways of disposed waters (under the pycnocline, at its upper boundary, and in the entire mixed layer) were analyzed on the basis of studying vertical displacement of biomasses of H-Bact, SYN, and prochlorophytes. Possibility of using optical anomalies distinguished from satellite data as markers of anthropogenic eutrophication caused by dumping was confirmed. Application of such markers depends on water transparency and on shapes of curves of vertical distribution of autotrophic organisms.