Oak Ridge National Laboratory

About: Oak Ridge National Laboratory is a facility organization based out in Oak Ridge, Tennessee, United States. It is known for research contribution in the topics: Neutron & Ion. The organization has 31868 authors who have published 73724 publications receiving 2633689 citations. The organization is also known as: ORNL.

Effects of Atmospheric CO2 Enrichment on the Growth and Mineral Nutrition of Quercus alba Seedlings in Nutrient-Poor Soil

Abstract: One-year-old dormant white oak (Quercus alba L.) seedlings were planted in a nutrient-deficient forest soil and grown for 40 weeks in growth chambers at ambient (362 microliters per liter) or elevated (690 microliters per liter) levels of CO2. Although all of the seedlings became severely N deficient, CO2 enrichment enhanced growth by 85%, with the greatest enhancement in root systems. The growth enhancement did not increase the total water use per plant, so water-use efficiency was significantly greater in elevated CO2. Total uptake of N, S, and B was not affected by CO2, therefore, tissue concentrations of these nutrients were significantly lower in elevated CO2. An increase in nutrient-use efficiency with respect to N was apparent in that a greater proportion of the limited N pool in the CO2-enriched plants was in fine roots and leaves. The uptake of other nutrients increased with CO2 concentration, and P and K uptake increased in proportion to growth. Increased uptake of P by plants in elevated CO2 may have been a result of greater proliferation of fine roots and associated mycorrhizae and rhizosphere bacteria stimulating P mineralization. The results demonstrate that a growth response to CO2 enrichment is possible in nutrient-limited systems, and that the mechanisms of response may include either increased nutrient supply or decreased physiological demand.

The Community Land Model and Its Climate Statistics as a Component of the Community Climate System Model

Abstract: Several multidecadal simulations have been carried out with the new version of the Community Climate System Model (CCSM). This paper reports an analysis of the land component of these simulations. Global annual averages over land appear to be within the uncertainty of observational datasets, but the seasonal cycle over land of temperature and precipitation appears to be too weak. These departures from observations appear to be primarily a consequence of deficiencies in the simulation of the atmospheric model rather than of the land processes. High latitudes of northern winter are biased sufficiently warm to have a significant impact on the simulated value of global land temperature. The precipitation is approximately doubled from what it should be at some locations, and the snowpack and spring runoff are also excessive. The winter precipitation over Tibet is larger than observed. About two-thirds of this precipitation is sublimated during the winter, but what remains still produces a snowpack tha...

Ferroelectricity in the magnetic E-phase of orthorhombic perovskites.

Abstract: We show that the symmetry of the spin zigzag chain E phase of the orthorhombic perovskite manganites and nickelates allows for the existence of a finite ferroelectric polarization. The proposed microscopic mechanism is independent of spin-orbit coupling. We predict that the polarization induced by the E-type magnetic order can potentially be enhanced by up to 2 orders of magnitude with respect to that in the spiral magnetic phases of TbMnO3 and similar multiferroic compounds.