Search results for " sink"
showing 10 items of 62 documents
The role of vineyards in the carbon balance throughout Italy
2015
A common belief is that agricultural fields cannot be net carbon sinks, but perennial tree crops, growing a permanent woody structure with a life cycle of decades could act as carbon sink. Vineyards are good candidates to test this hypothesis, because they are often grown with limited soil cultivation and produce plenty of woody pruning material that can be left on the ground. Three Eddy Covariance sites were established in different vineyards, along a north-south transect, in Italy, to study the role of vine cultivation in the carbon balance of the Italian penisula. The year 2009 was chosen as a reference year for the three sites, in order to compare carbon budget estimates in areas charac…
Compensatory water effects link yearly global land CO2 sink changes to temperature
2017
Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems1–3. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales3–14. Here we use empirical models based on eddy covariance data15 and process-based models16,17 to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of…
Carbon autonomy of peach shoots determined by 13C-photoassimilate transport
2009
We used (13)CO(2) tracing and source-sink manipulation to determine if fruiting shoots of peach (Prunus persica (L.) Batsch) trees are autonomous or if they import carbon from neighboring shoots, and if the degree of shoot autonomy is influenced by the source-sink relationship of the shoot. In three experiments, leaf to fruit ratio (L:F) of selected fruiting shoots was moderately (2005 and 2006) or strongly (complete sink removal, 2006) altered to either enhance or inhibit movement of carbon from (13)C-labeled fruiting shoots (LFS) to adjacent non-labeled shoots (NLFS), both located within 10 cm on the same main scaffold of V-shaped peach trees. At Stages I and III of fruit growth, fruit an…
Influence of 150 Years of Land Use on Anthropogenic and Natural Carbon Stocks in Emilia-Romagna Region (Italy)
2011
Changes in land use/cover that are commonly associated with urbanization can dramatically influence the amount, chemical form, and spatial distribution of carbon (C) stocks. Measured values and relative literature for composition of natural and anthropogenic materials have been compiled. These data are used in conjunction with land cover statistics and expert assessment of building design to calculate C stocks associated with 150 years of land use change and development for an area of the Po River Valley, Northern Italy. Using 4 time periods (1853, 1954, 1976, and 2003), we demonstrate that the C stocks within this densely populated area have undergone considerable modification. A 52% incre…
Forearc carbon sink reduces long-term volatile recycling into the mantle
2019
Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent…
The carbon count of 2000 years of rice cultivation.
2013
More than 50% of the world's population feeds on rice. Soils used for rice production are mostly managed under submerged conditions (paddy soils). This management, which favors carbon sequestration, potentially decouples surface from subsurface carbon cycling. The objective of this study was to elucidate the long-term rates of carbon accrual in surface and subsurface soil horizons relative to those of soils under nonpaddy management. We assessed changes in total soil organic as well as of inorganic carbon stocks along a 2000-year chronosequence of soils under paddy and adjacent nonpaddy management in the Yangtze delta, China. The initial organic carbon accumulation phase lasts much longer a…
Carbohydrate availability affects growth and metabolism in peach fruit
2008
Along with sucrose, sorbitol represents the main photosynthetic product and form of translocated carbon in peach. This study aimed at determining whether peach fruit carbohydrate metabolism is affected by changes in source-sink balance, and specifically whether sorbitol or sucrose availability regulates fruit enzyme activities and growth. In various trials, different levels of assimilate availability to growing fruits were induced in vivo, by varying crop load of entire trees, leaf:fruit ratio (L:F) of fruiting shoots, or by interrupting the phloem stream (girdling) to individual fruits. In vitro, fruit tissue was incubated in presence/absence of sorbitol and sucrose. Relative growth rate (…
Analysis of Protected Accidental Transients in the EFIT Reactor With the RELAP5 Thermal-Hydraulic Code
2008
The European Facility for Industrial Transmutation (EFIT) is aimed at demonstrating the feasibility of transmutation process through the Accelerator Driven System (ADS) route on an industrial scale. The conceptual design of this reactor of about 400 MW thermal power is under development in the frame of the European EUROTRANS Integrated Project of the EURATOM Sixth Framework Program (FP6). EFIT is a pool-type reactor cooled by forced circulation of lead in the primary system where the heat is removed by steam generators installed inside the reactor vessel. The reactor power is sustained by a spallation neutron source supplied by a proton beam impinging on a lead target at the core centre. A …
Comparing soil inventory with modelling: Carbon balance in central European forest soils varies among forest types
2018
Abstract Forest soils represent a large carbon pool and already small changes in this pool may have an important effect on the global carbon cycle. To predict the future development of the soil organic carbon (SOC) pool, well-validated models are needed. We applied the litter and soil carbon model Yasso15 to 1838 plots of the German national forest soil inventory (NFSI) for the period between 1985 and 2014 to enables a direct comparison to the NFSI measurements. In addition, to provide data for the German Greenhouse Gas Inventory, we simulated the development of SOC with Yasso15 applying a climate projection based on the RCP8.5 scenario. The initial model-calculated SOC stocks were adjusted…
Fight on plankton! Or, phytoplankton shape and size as adaptive tools to get ahead in the struggle for life
2011
A renewed interest in investigating the relationships existing between body size and environmental variables is pervading ecological studies. Phytoplankton has a long tradition as model system in studies of community ecology and several research concepts were developed using these organisms. In this paper we try to review the relevance of analyzing the morphological features of phytoplankton in ecology. Starting with a brief account of allometric relationships existing in phytoplankton, we i) examine the physical context in which phytoplankton grow, and ii) highlight the role of their size in nutrient uptake, and that of their shape in light harvesting. Moreover, the way in which the morpho…