228 results for group: journal-article
Nitrogen in rock: Occurrences and biogeochemical implications
JoAnn M. Holloway,Randy A. Dahlgren
Abstract
There is a growing interest in the role of bedrock in global nitrogen cycling and potential for increased ecosystem sensitivity to human impacts in terrains with elevated background nitrogen concentrations. Nitrogen-bearing rocks are globally distributed and comprise a potentially large pool of nitrogen in nutrient cycling that is frequently neglected because of a lack of routine analytical methods for quantification. Nitrogen in rock originates as organically bound nitrogen associated with sediment, or in thermal waters representing a mixture of sedimentary, mantle, and meteoric sources of nitrogen. ...
Quorum Sensing in Nitrogen-Fixing Rhizobia
Juan E. González and Melanie M. Marketon
Abstract
Members of the rhizobia are distinguished for their ability to establish a nitrogen-fixing symbiosis with leguminous plants. While many details of this relationship remain a mystery, much effort has gone into elucidating the mechanisms governing bacterium-host recognition and the events leading to symbiosis. Several signal molecules, including plant-produced flavonoids and bacterially produced nodulation factors and exopolysaccharides, are known to function in the molecular conversation between the host and the symbiont. Work by several laboratories has shown that an additional mode of regulat...
Critical evaluation of strategies for mineral fortification of staple food crops
Sonia Gómez-Galera, Eduard Rojas, Duraialagaraja Sudhakar, Changfu Zhu, Ana M Pelacho, Teresa Capell, Paul Christou
Abstract
Staple food crops, in particular cereal grains, are poor sources of key mineral nutrients. As a result, the world's poorest people, generally those subsisting on a monotonous cereal diet, are also those most vulnerable to mineral deficiency diseases. Various strategies have been proposed to deal with micronutrient deficiencies including the provision of mineral supplements, the fortification of processed food, the biofortification of crop plants at source with mineral-rich fertilizers and the implementation of breeding ...
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...
