These thresholds influenced calculation of reference nutrient concentrations, and ignoring them led to higher estimates of these concentrations. Kimball, eds Ecotoxicology: Problems and Approaches. Downing, Evidence for regional nitrogen stress on chlorophyll a in lakes across large landscape and climate gradients , Limnology and Oceanography , 63 , S1 , S324-S339 , 2017. We explore whether mid-Holocene African savannas were dominated by herbivory as a means of cycling nutrients, and whether fire perhaps played a lesser role than today. Nutrient fluxes to coastal areas have risen in recent decades, leading to widespread hypoxia and other ecological damage, particularly from nitrogen N.
Issues in Ecology 1 1 : 1—15. Inputs of sediment and carbon to an estuarine ecosystem: influence of land use. Non-point sources of nitrogen dominate the flux in all regions. Sadowsky and Miki Hondzo, The Effects of Turbulence and Carbon Amendments on Nitrate Uptake and Microbial Gene Abundances in Stream Sediment , Journal of Geophysical Research: Biogeosciences , 123 , 4 , 1289-1301 , 2018. Soil and water quality parameters from different land uses were extracted from 89 soil and 18 water studies in different regions across the Cerrado.
Some aspects of the N budget for savannas of the American continent are still unclear and require further analysis to determine rates of N fixation, and to understand how spatial and temporal soil heterogeneity control N fluxes through soil solution and into streams. Scientific American 302 2, Feb 2010 : 64-71. We also found significant thresholds that indicated strong increases in nutrient concentrations with modest increases in urbanization reaching maximum nutrient concentrations between 10 and 46% urban cover. Reed, Bacterial, fungal, and plant communities exhibit no biomass or compositional response to two years of simulated nitrogen deposition in a semiarid grassland , Environmental Microbiology , 19 , 4 , 1600-1611 , 2017. Nitrogen use in the United States from 1961-2000 and potential future trends.
Limnology and Oceanography 40 3 : 639—643. The Biological Bulletin 203 2 : 261—263. Nitrogen inputs to Brazil from human activities practically doubled from 1995 to 2002, mostly because of nitrogen production through biological fixation in agricultural systems. Seed inoculation with Azospirillum is an alternative that favors the incorporation of green agriculture in regions of conventional farming, such as the Brazilian savannah Cerrado. The vast majority of nitrogen on Earth is present as molecular N2, and before the advent of the agricultural and industrial revolutions, biological nitrogen fixation was the only significant process creating reactive nitrogen. In the short-term, nutrients such as N and carbon can be lost from the soil by volatilisation Kauffman et al.
Salt marsh detritus: an alternative interpretation of stable carbon isotope ratios and the fate of Spartina alterniflora. Ecosystems 5 7 : 719—725. Raisbeck and Françoise Yiou, Denudation rates determined from the accumulation of in situ-produced 10Be in the luquillo experimental forest, Puerto Rico , Earth and Planetary Science Letters , 10. This survey was made by collecting seedling from the forest with intact root systems, registering the presence of nodules and the type of soil were the collection was made. Determining the ecological effects of oil pollution in marine ecosystems. In this context, the Brazilian La Plata Basin contributes to the alteration of the nitrogen cycle in South America because of its huge agricultural and grazing area that meets the demands of its large urban centres - Sao Paulo, for instance - and also external markets abroad.
Further interpretation using the model revealed the processes of P loading to the lake. Of two modified chlorophyll models which depend explicitly on both nitrogen and phosphorus developed and tested, one, a multiple regression model, appears to greatly reduce the error of chlorophyll prediction in lakes. At present, most governmental agencies that regulate chronic sources of oil pollution rely on an excessively simplistic approach to estimate damage: determination of lethal toxicity in short-term bioassays. Limnology and Oceanography 45 8 : 1889. Braun, Vegetation impact on stream chemical fluxes: Mule Hole watershed South India , Geochimica et Cosmochimica Acta , 10. The ecological significance of sulfur in the energy dynamics of salt marsh and coastal marine sediments. The main inputs of nitrogen to the region are biological nitrogen fixation occurring in tropical forests 7.
As excessive consumption of food and energy, etc. The regulation of decomposition and heterotrophic microbial activity in salt marsh soils. Pyrite formation and the measurement of sulfate reduction in salt marsh sediments. Herbaceous C declined with increasing aboveground Prosopis C on clay loams, but increased with increasing Prosopis C on shallow clays. Essas mudanças no uso e cobertura da terra afetam de maneira expressiva a dinâmica da matéria orgânica do solo, que é fundamental na manutenção do ciclo do carbono e do nitrogênio nos ecossistemas.
Nitrogen cycling and anthropogenic impact in the tropical inter-American seas. Grazing and conversion to pasture have been the predominant land-use changes in most savannas. Buss, María Chapela Lara, Oliver W. Methane emissions and climatic warming risk from hydraulic fracturing and shale gas development: implications for policy. Limnology and Oceanography 51 1 : 25—376.
Climatic control on eutrophication of the Hudson River Estuary. Atmospheric deposition of nitrogen oxides onto the landscape contributes to coastal eutrophication in the Northeast United States. Hendrickx, James Juvik, Jeffrey McDonnell and Fred Ogden, The hydrology of the humid tropics , Nature Climate Change , 10. Linking environmental nutrient enrichment and disease emergence in humans and wildlife. Labelled elemental sulfur which formed in situ during the incubations at depths below 1 cm made up a fairly constant 5—11% of the total labelled reduced sulfur, from 0—1 cm, it made up 27%. Spatial heterogeneity in lake communities: The benthos and habitat interactions. With the ascendancy of ecosystem science and management, the need has arisen for a comprehensive treatment of techniques used in this rapidly-growing field.