Measuring the Impact of Hydrocarbons on Rates of Nitrogen Fixation

2015 ◽  
pp. 81-97
Author(s):  
Florin Musat ◽  
Niculina Musat
Keyword(s):  
Nitrogen Fixation ◽  
The Impact

scholarly journals How can effect the synergy of climate change, soil units and vegetation groups the potential global distribution of plants up to 2300: a modelling study for prediction of potential global distribution and migration of the N<sub>2</sub> fixing species <i>Alnus</i> spp.

2015 ◽  
Vol 12 (1) ◽  
pp. 815-864
Author(s):  
A. Sakalli
Keyword(s):  
Climate Change ◽  
Nitrogen Fixation ◽  
Global Distribution ◽  
Plant Distribution ◽  
Climate Change Scenarios ◽  
Climate System Model ◽  
Current Time ◽  
Soil Units ◽  
And Migration ◽  
The Impact

Abstract. Plant migration is a well known adaptation strategy of plant groups or species with evidence from historical to present observation and monitoring studies. Importance of N2-fixing plants has increased in last decades. Alnus (alder) is an important plant group because of its nitrogen fixation ability. Alders are generally distributed in humid locations of boreal, temperate and tropical climate zones, where the nitrogen fixation is an important nitrogen source for other plants. To model the nitrogen fixation by alder, data about the global distribution of alder is absolutely required. In this study a new method and model are presented to predict the distribution of N2-fixing genus on global scale and its migration in the future by using climate change scenarios. Three linear functions were defined for the determination of climate niche of alders. The distribution and migration model (Alnus-Distribution-Model (ADM)) was improved with the aid of the soil units from FAO-Unesco Soil Database, and vegetation types from Schmithüsen's biogeographical atlas. The model was also developed to predict the impact of climate change on alder distribution by using climate data from experiments performed by the Community Climate System Model version 4 (CCSM4) including the representative concentration pathways (RCPs) mitigation scenarios, and extensions of the scenarios beyond 2100 to 2300. The model covered basic approaches to understand the combine effect of climate, soil and vegetation on plant distribution and migration in the current time and future.

scholarly journals Influence of the Amazon River on dissolved and intra-cellular metal concentrations in <i>Trichodesmium</i> colonies along the western boundary of the sub-tropical North Atlantic Ocean

2011 ◽  
Vol 8 (1) ◽  
pp. 217-225 ◽  
Author(s):  
A. Tovar-Sanchez ◽  
S. A. Sañudo-Wilhelmy
Keyword(s):  
Nitrogen Fixation ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Amazon River ◽  
Physical Parameters ◽  
Metal Concentrations ◽  
Field Samples ◽  
Metal Composition ◽  
The Impact

Abstract. Despite the ecological importance of Trichodesmium spp. for the global oceanic nitrogen budget, there is limited information on their trace metal composition in field samples. We report dissolved (<0.22 μm) metal concentrations measured in surface waters (Ag, Cd, Co, Cu, Fe, Mo, Ni, P, Pb and V) and in the total and the intracellular pool (Ag, Al, Cd, Co, Cu, Fe, Mn, Mo, Ni, P, Pb, V) of Trichodesmium populations collected in the western subtropical North Atlantic Ocean (April–May 2003) within the influence of the Amazon River plume. Dissolved element distributions were strongly influenced by the River discharge, with concentrations of some elements varying directly (i.e. Cd, Mo and V) or inversely (Ag, Co, Cu, Fe, Ni, P and Pb) with surface salinity. Intracellular metal values to phosphorous ratios (mol:mol) for Cd, Co, Cu, Fe, Mn, Mo, Ni and V ranged from 9.0 × 10−6 for Cd to 4.4 × 10−2 for Fe. Although total metal composition was significantly correlated with the intracellular content in the Trichodesmium colonies for some elements (e.g., Co, Cu, V), metal pools in the phytoplankton did not co-vary with the dissolved metal concentrations, suggesting that water column measurements may not be good predictors of the intracellular metal concentrations. The impact of physical parameters and bioactive elements on biological processes such as nitrogen fixation, carbon drawdown and biomass production in Trichodesmium colonies was explored by using a principal component analysis test (PCA). The analysis indicated that the biological drawdown of dissolved inorganic carbon (DIC) by Trichodesmium seems to be influenced by the internal content of Fe, Co, Cd, and Cu, while nitrogen fixation seems more influenced by mixed layer depth and dissolved Fe and Ni concentrations.

scholarly journals European perspectives on nitrogen fixation and the application of mineral nitrogen

1996 ◽  
Vol 6 ◽  
pp. 95-98
Author(s):  
L.R. Mytton
Keyword(s):  
Nitrogen Fixation ◽  
Agricultural Policy ◽  
Common Agricultural Policy ◽  
The European Union ◽  
Factors Influencing ◽  
The Common ◽  
Fertiliser Use ◽  
Major Factors ◽  
The Impact ◽  
Farm Subsidies

An analysis is made of the main factors influencing nitrogen use in the European Union (EU). The Common Agricultural Policy (CAP) is identified as a major factor. A brief explanation is given of its functions and of recent reforms which are aimed at reducing overproduction. These reforms should favour more efficient use of nitrogen. The reasons why this is difficult to achieve are explained and the major factors influencing our ability to balance the nitrogen economies of food production are identified. The interrelationship between these factors is then used to predict the impact of CAP reforms on research, on fertiliser use and on the wider use of legumes. Keywords: Common Agricultural Policy, Europe, farm subsidies, legumes, nitrogen cycle, nitrogen fertiliser, nitrogen fixation, over-production, pollution, soil organic matter

scholarly journals Burrowing deeper into benthic nitrogen cycling: the impact of bioturbation on nitrogen fixation coupled to sulfate reduction

2010 ◽  
Vol 409 ◽  
pp. 1-15 ◽  
Author(s):  
VJ Bertics ◽  
JA Sohm ◽  
T Treude ◽  
CET Chow ◽  
DG Capone ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Cycling ◽  
Sulfate Reduction ◽  
The Impact

scholarly journals Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean

2006 ◽  
Vol 3 (5) ◽  
pp. 1391-1451 ◽  
Author(s):  
V. J. Coles ◽  
R. R. Hood
Keyword(s):  
Nitrogen Fixation ◽  
Atlantic Ocean ◽  
N2 Fixation ◽  
Iron Concentration ◽  
Near Surface ◽  
Dissolved Iron ◽  
Dynamic Representation ◽  
The Impact ◽  
Nitrogen Phosphorus ◽  
Do So

Abstract. The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997) anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N2 fixation that are required to do so. We present results from an Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N2 fixation with light, nitrogen, phosphorus and iron limitations, and variable stoichiometric ratios. The model is able to reproduce nitrogen, phosphorus and iron concentration variability to first order. The latter is achieved by incorporating iron deposition directly into the model's detritus compartment which allows the model to reproduce sharp near surface gradients in dissolved iron concentration off the west coast of Africa and deep dissolved iron concentrations that have been observed in recent observational studies. The model can reproduce the large scale N* anomaly patterns but requires relatively high rates of surface nitrogen fixation to do so (1.8×1012 moles N yr−1 from 10° N–30° N, 3.4×1012 moles N yr

scholarly journals Nonspecific Symbiosis Between Sophora flavescens and Different Rhizobia

2018 ◽  
Vol 31 (2) ◽  
pp. 224-232 ◽  
Author(s):  
Yuan Hui Liu ◽  
Yin Shan Jiao ◽  
Li Xue Liu ◽  
Dan Wang ◽  
Chang Fu Tian ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Host Specificity ◽  
Genetic Basis ◽  
Negative Regulator ◽  
Related Gene ◽  
Nod Factors ◽  
Wild Type ◽  
Sophora Flavescens ◽  
Tn5 Mutants ◽  
The Impact

We explored the genetic basis of the promiscuous symbiosis of Sophora flavescens with diverse rhizobia. To determine the impact of Nod factors (NFs) on the symbiosis of S. flavescens, nodulation-related gene mutants of representative rhizobial strains were generated. Strains with mutations in common nodulation genes (nodC, nodM, and nodE) failed to nodulate S. flavescens, indicating that the promiscuous nodulation of this plant is strictly dependent on the basic NF structure. Mutations of the NF decoration genes nodH, nodS, nodZ, and noeI did not affect the nodulation of S. flavescens, but these mutations affected the nitrogen-fixation efficiency of nodules. Wild-type Bradyrhizobium diazoefficiens USDA110 cannot nodulate S. flavescens, but we obtained 14 Tn5 mutants of B. diazoefficiens that nodulated S. flavescens. This suggested that the mutations had disrupted a negative regulator that prevents nodulation of S. flavescens, leading to nonspecific nodulation. For Ensifer fredii CCBAU 45436 mutants, the minimal NF structure was sufficient for nodulation of soybean and S. flavescens. In summary, the mechanism of promiscuous symbiosis of S. flavescens with rhizobia might be related to its nonspecific recognition of NF structures, and the host specificity of rhizobia may also be controlled by currently unknown nodulation-related genes.

scholarly journals Overview and vision for white clover

1996 ◽  
Vol 6 ◽  
pp. 1-6
Author(s):  
J.R. Caradus ◽  
D.R. Woodfield ◽  
A.V. Stewart
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Nutritive Value ◽  
Animal Feed ◽  
Economic Value ◽  
Forage Yield ◽  
Yield Potential ◽  
Challenges And Opportunities ◽  
Transgenic Technologies ◽  
The Impact

White clover (Trifolium repens L.) is the key to the international competitive advantage of New Zealand's pastoral industries, which are reliant on a cheap, high quality feed source. White clover benefits pastoral agriculture through its ability to fix nitrogen, its high nutritive value, its seasonal complementarity with grasses, and its ability to improve animal feed intake and utilisation rates. The annual financial contribution of white clover through fixed nitrogen, forage yield, seed production and honey production is estimated as $3.095 billion. The impact of white clover has resulted from understanding how it grows, and then developing appropriate management systems, fertiliser strategies, and improved cultivars. While the future of white clover as the legume base of our pasture is secure there are challenges and opportunities ahead. These include the increasing use of mineral nitrogen, competitiveness with high endophyte ryegrasses, filling gaps in our knowledge base, responding to industry signals, the advent of transgenic technologies, the removal of anti-quality characters particularly those associated with the incidence of bloat, and assuring that nitrogen fixation rates, in grazed pastures, increase as the yield potential of white clover is itself increased. Keywords: economic value, nitrogen fixation, nutritive quality, pastoral agriculture, white clover

scholarly journals A~simple model for predicting the global distribution of the N<sub>2</sub> fixing host genus <i>Alnus Mill.</i>: impact of climate change on the global distribution in 2100

2013 ◽  
Vol 10 (8) ◽  
pp. 13049-13095 ◽  
Author(s):  
A. Sakalli
Keyword(s):  
Climate Change ◽  
Nitrogen Fixation ◽  
Climate Models ◽  
Global Distribution ◽  
Linear Functions ◽  
Distribution Model ◽  
Climate Data ◽  
Host Genus ◽  
Impact Of Climate Change ◽  
The Impact

Abstract. The importance of N2-fixing plants has increased in last decades. Alnus (alder) is an important plant group because of its nitrogen fixation ability. Alders are generally distributed in humid locations of boreal, temperate and tropical climate zones, where the nitrogen fixation is an important nitrogen source for other plants. To model the nitrogen fixation by alder, data about the global distribution of alder is absolutely required. In this study a new method and model to predict the distribution of N2-fixing genus on global scale is presented. Three linear functions were defined for the determination of climate area of alder locations. The distribution model was improved with the aid of the soil units from FAO-Unesco Soil Database, and vegetation types from Schmithüsen's biogeographical atlas. The model (Alnus-Distribution-Model, ADM) was also developed to predict the impact of climate change on alder distribution by using climate data of five relevant climate models (PCM, ECHam4, HadCM3, CSIRO2 and CGCM2), and four IPCC climate scenarios (i.e. A1FI, A2, B1 and B2) in 2100. The model covered basic approaches to understand the climate change effect on plant migration in the future.

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