165 results for group: journal-article
Amazonia as a carbon source linked to deforestation and climate change
Luciana V. Gatti, Luana S. Basso, John B. Miller, Manuel Gloor, Lucas Gatti Domingues, Henrique L. G. Cassol, Graciela Tejada, Luiz E. O. C. Aragão, Carlos Nobre, Wouter Peters, Luciano Marani, Egidio Arai, Alber H. Sanches, Sergio M. Corrêa, Liana Anderson, Celso Von Randow, Caio S. C. Correia, Stephane P. Crispim & Raiane A. L. Neves
Abstract
Amazonia hosts the Earth’s largest tropical forests and has been shown to be an important carbon sink over recent decades1,2,3. This carbon sink seems to be in decline, however, as a result of factors such as deforestation and climate change1,2,3. Here we investigate Amazonia’s carbon budget and ...
Diverging patterns at the forest edge: Soil respiration dynamics of fragmented forests in urban and rural areas
Sarah M. Garvey, Pamela H. Templer, Erin A. Pierce, Andrew B. Reinmann, Lucy R. Hutyra
Abstract
As urbanization and forest fragmentation increase around the globe, it is critical to understand how rates of respiration and carbon losses from soil carbon pools are affected by these processes. This study characterizes soils in fragmented forests along an urban to rural gradient, evaluating the sensitivity of soil respiration to changes in soil temperature and moisture near the forest edge. While previous studies found elevated rates of soil respiration at temperate forest edges in rural areas compared to the forest interior, we find that soil ...
Soil and foliar application of rock dust as natural control agent for two-spotted spider mites on tomato plants
Nicoletta Faraone, Rodger Evans, Julia LeBlanc & Neil Kirk Hillier
Abstract
Mineral-based products represent a valid alternative to synthetic pesticides in integrated pest management. We investigated the effects of a novel granite dust product as an agent for controlling two-spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae), on tomato plants (Solanum lycopersicum L.). Two-choice tests for repellency and repulsiveness, and no-choice bioassays with different type of applications (soil, foliar, and soil–foliar) were used in order to evaluate performance and action of the product. Evaluation of epidermal micromorphology and ...
Ants as a powerful biotic agent of olivine and plagioclase dissolution
Ronald I. Dorn
Abstract
The biotic enhancement of Ca-Mg silicate weathering has helped maintain Earth’s habitability over geological time scales by assisting in the gradual drawdown of atmospheric CO2. 25 years of in-situ measurements of Ca-Mg silicate mineral dissolution by ants, termites, root mats, bare ground, and a control reveals ants to be one of the most powerful biotic weathering agents yet recognized. Six sites in Arizona and Texas (USA) indicate that eight different ant species enhance mineral dissolution by ∼50×–300× over controls. A comparison of extracted soil at a 50 cm depth in ant colonies and adjacent bare ground shows ...
Ocean acidification effects on in situ coral reef metabolism
Steve S. Doo, Peter J. Edmunds & Robert C. Carpenter
Abstract
The Anthropocene climate has largely been defined by a rapid increase in atmospheric CO2, causing global climate change (warming) and ocean acidification (OA, a reduction in oceanic pH). OA is of particular concern for coral reefs, as the associated reduction in carbonate ion availability impairs biogenic calcification and promotes dissolution of carbonate substrata. While these trends ultimately affect ecosystem calcification, scaling experimental analyses of the response of organisms to OA to consider the response of ecosystems to OA has proved difficult. The benchmark of ecosyst...
Effectiveness of enhanced mineral weathering as a carbon sequestration tool and alternative to agricultural lime: An incubation experiment
Christiana Dietzen, Robert Harrison, Stephani Michelsen-Correa
Abstract
Applying finely ground silicate minerals to soils could mitigate CO2 emissions by enhancing the rate of carbon sequestration via silicate weathering. Using these minerals instead of agricultural lime to increase soil pH would also eliminate the dissolution of lime as a major source of agricultural CO2 emissions. However, dissolution rates of silicate minerals in the soil environment are uncertain and impacts of their application on the decomposition of soil organic matter have yet to be determined. A 3-month soil incubation was performed to investigate the effects ...
Changes in USDA food composition data for 43 garden crops, 1950 to 1999
Donald R Davis 1, Melvin D Epp, Hugh D Riordan
Summary
Objectives: To evaluate possible changes in USDA nutrient content data for 43 garden crops between 1950 and 1999 and consider their potential causes.
Methods: We compare USDA nutrient content data published in 1950 and 1999 for 13 nutrients and water in 43 garden crops, mostly vegetables. After adjusting for differences in moisture content, we calculate ratios of nutrient contents, R (1999/1950), for each food and nutrient. To evaluate the foods as a group, we calculate median and geometric mean R-values for the 13 nutrients and water. To evaluate R-values for individual foods and ...
Declining Fruit and Vegetable Nutrient Composition: What Is the Evidence?
Donald R. Davis
Abstract
Three kinds of evidence point toward declines of some nutrients in fruits and vegetables available in the United States and the United Kingdom: 1) early studies of fertilization found inverse relationships between crop yield and mineral concentrations—the widely cited “dilution effect”; 2) three recent studies of historical food composition data found apparent median declines of 5% to 40% or more in some minerals in groups of vegetables and perhaps fruits; one study also evaluated vitamins and protein with similar results; and 3) recent side-by-side plantings of low- and high-yield cultivars of broccoli and grains ...
Forest soil carbon is threatened by intensive biomass harvesting
David L. Achat, Mathieu Fortin, Guy Landmann, Bruno Ringeval & Laurent Augusto
Abstract
Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers’ decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventional biomass harvests preserved the SOC of forests, unlike intensive harvests where logging residues were harvested to produce fuelwood. Conventional harvests caused ...
