Impact of Nitrogen on Carbon Stocks

Impact of Nitrogen on Carbon Stocks 2. Literature Review: This chapter will provide an overview of; the scientific basis behind why adding nitrogen will cause an increase in carbon stocks, the impacts of nitrogen deposition on tree carbon stocks documented in the current literature, the impacts of nitrogen deposition on soil carbon stocks documented in the current literature and information more specifically targeted at the UK and the South Downs. 2.1. The global nitrogen cycle The nitrogen cycle is strongly coupled with the carbon cycle, this dependence on one another and key feedbacks is illustrated in figure 2. 1. If the availability of one of these elements changes it will affect the biochemical cycle of the other element and eventually the functioning of the entire ecosystem (Gruber Galloway, 2008). Reactive nitrogen (Nr) is a requirement for the growth of plants and soil microorganisms, the processes of both play key roles in the global carbon cycle. The rise in anthropogenic CO2 has been observed to increase plant photosynthesis and therefore plant growth and carbon storage (Oren et al., 2001). This growth however can be limited by the levels of Nr available in soils (Vitousek and Howarth, 1991), hence in Nr poor ecosystems the potential carbon sink could be limited. In some regions it is conceivable that anthropogenic production of Nr could provide the nutrients necessary to reduce limitations on plant growth (Ciais et al., 1995). Prior to the industrial revolution reactive nitrogen, any form of nitrogen species other than N2, was only made available to the terrestrial ecosystem by natural processes, such as biological nitrogen fixation (BNF) and lightening, since industrialisation a number of sources of Nr have become much more significant (Figure 2.2). BNF allows the terrestrial ecosystem to acquire essential nitrogen compounds a through a series of reactions that convert N2 into ammonia (Ciais et al., 2013). Initially there was an equilibrium between the input of Nr to the ecosystem and its loss through the process of denitrification, however since industrialisation this equilibrium no longer exists. Humans produce a quantity of Nr that is much greater than that produced naturally in ecosystems. This Nr is produced by humans in a number of wa ys: 1) it is produced industrially by the Haber-Bosch process, producing NH3 as a fertiliser for crops, this nitrogen is then spread through run off and emission into the atmosphere; 2) the growth of crops such as legumes that are associated with mycorrhizal fungi and higher levels of BNF (Hayman, 1986); and 3) the combustion of fossil fuels which converts N2 and fossil fuel nitrogen into nitrous oxides (NOx) which are emitted into the atmosphere and then deposited on terrestrial ecosystems and the ocean (Ciais et al., 2013). This undeniable evidence of the anthropogenic perturbation of the nitrogen cycle and the close relationship between the nitrogen cycle and the carbon cycle highlights the need to understand how additions of nitrogen will interact with the carbon cycle, and in what way this will impact carbon sinks and therefore feedback to the climate. The increased supply of Nr can be expected to increase terrestrial CO2 uptake by increasing NPP (net primary productivity) (chapter 2.2.1) or reducing the rate of organic matter breakdown (chapter 2.2.2). It must be noted however that additions of Nr will not exclusively increase CO2 uptake by the terrestrial biosphere: negative direction (in situations where it accelerates organic matter breakdown)-> ) O3 formed in the troposphere as a result of NOx and volatile organic compound emissions reduces plant productivity, and therefore reduces CO2 uptake from the atmosphere. On the global scale the net influence of the direct and indirect contributions of Nr on the radiative balance was estimated to be –0.24 W m–2 (with an uncertainty range of +0.2 to –0.5 W m–2)(Erisman et al., 2011). The balance between the directions will determine the potential. 2.2.1 Forest Carbon Uptake- Trees Various studies have assessed the possible impact of increased nitrogen on tree carbon stock and a variety of methods have been employed. One approach involves assessing the relationship between the spatial trends of carbon uptake, found by study of forest growth or net ecosystem production (NEP), and nitrogen deposition. In their 2007 study Magnani et al. employed a variation of this technique. Carbon stocks and their fluxes were measured in 5 representative chronosequences in Europe. In addition data from the literature, from a further 13 chronosequences and two uneven aged stands were used. Estimates of wet deposition of nitrogen were calculated from various data sets. The relationship between wet nitrogen deposition and NEP was then analysed graphically and statistically. Studies of the influence of nitrogen deposition at stand level have also been carried out, one example of this is a study by Solberg et al. (2009). The impact of nitrogen deposition was evaluated by using deposi tion values from the growth period (1993-2000). These values were then correlated with the values for relative volume which was calculated as actual increment in % of expected increment. In their study Magnani et al. (2007) found a strong relationship between C sequestration and wet N-deposition (Figure 2.3d) with an R2 value of 0.97. Though they found this relationship was largely obscured by age effects when individual stands were considered. Solberg et at. (2009) found that nitrogen deposition had a fertilising effect of slightly higher than 1% increase in volume increment per kg N ha-1 yr-1. The results of these papers can be converted into nitrogen uptake efficiency (NUE) in order to make them comparable, where NUE is the response of carbon sequestration to nitrogen deposition in kg C/kg N (de Vries et al., 2009). Thus it was calculated that Magnani et al. (2007) found an NUEeco value of approximately 475 kg C/ kg N (de Vries et al., 2009). Sutton et al. (2008) found this value to be unlikely and tested the data against more appropriate N-depostion values for the period suggested and produced results calculated by de Vries et al. (2009) to be between 91 and 177 kg/C/N. The NUE value for trees in the study by Solberg et al. (2009) were calculated to be equivalent to 19-38 kg C/ kg N. Another important area of research in this field is the evaluation of C-N stoichiometry of ecosystem compartments because it strongly influences the potential for carbon fixation to respond to nitrogen deposition (de Vries et al., 2009). Nitrogen entering the ecosystem can be traced by applying isotopically labelled nitrogen (15N) to the forest floor and tracking its movement. Melin et al. (1983) applied this techniques in nitrogen-limited Scots pine stand in Sweden, to study the distribution and recovery of the labelled fertiliser. The application rate was 100kg of ammonium nitrate-N/ha. Nadelhoffer et al. (1999) carried out similar 15N tracer experiments in nine temperate forests for three years. Further to this de Vries et al. (2006) used the same methodology as Nadelhoffer et al. (1999) at over 6000 level I plots (From a large-scale forest condition monitoring scheme based on a 16 x 16 km gridnet across Europe). Site specific soil C/N ratios were utilised and the assumption of an increase of upto 0.1 of N retention fractions in stem wood that are influenced by N deposition. Melin et al. (1983) reported a value of between 12 and 28% of nitrogen applied recovered in trees. De Vries et al. (2009) used the C/N ratio of 500 for stem wood estimated by Nadelhoffer et al.(1999) to calculate a NUEtree of 30-70 kg C/kg N. A NUEtree of 25 kg C/kg N was calculated in the same way for the results presented by Nadelhoffer et al. (1999) which showed 5% of nitrogen applied to be recovered in woody biomass. The results of direct fertilisation experiment methodologies are important to consider for this research paper, low doses of N fertiliser are applied to selected sites for a long-term (8-30 years) study. Hyvonen et al. (2008) ran experiments in Sweden and Finland in Picea abies and Pinus sylvestris stands. 15 sites were selected for long-term experimentation that ranged from 14 to 30 years. Low (30-50 kg N ha-1 yr-1) or high (50-200 kg N ha-1) doses of N-fertiliser either alone or in combination with other nutrients were applied to plots no smaller than 30 x 30 m. Diameter at breast height (DBH), number of trees ha-1 and tree height (when available) at each plot on each occasion of measurement were utilised to calculate biomass. The amount of carbon at each site was estimated to be 0.5 of the biomass. Changes in the C-pool was calculated for each site and the effect of N-fertilisation was calculated as the difference between the fertilised plots and the control plots. Pregitzer et al . (2007) applied 30 kg N ha-1 yr-1 from 1994 to 2004 to four different hardwood forests in Michigan. Tree growth was measured yearly and compared with control sites. Hogberg et al. (2006) ran a 30 year experiment in unpolluted boreal forest. N fertiliser (ammonium nitrate) was applied to replicated (N=3) 0.09 ha plots. 3 doses were prescribed, 34, 68 and 108 kg N ha-1 yr-1. The highest level of application was cancelled after 20 years to allow recovery to be assessed in the subsequent decade. Hyvonen et al. (2008) presented their results as kg C/kg N and so no further calculations were necessary. They found that for the low dose application of N NUEtree was 25 kg C/kg N whereas for high dose it was 11 kg C/kg N. NPK addition produced values of 38 and 11 kg C/kg N for low and high doses respectively. Pregitzer at al. (2007) found an increase of 5000 kg C ha-1 in woody biomass, with a total application of N of 300 kg N ha-1 for the whole study period this equates to 17 kg C/kg N (de Vries et al, 2009). Hogberg et al. (2006) found an initial increase in tree growth at all doses of nitrogen treatment. However in the long-term the impact of fertilisation was found to be highly rate dependant. The high dose showed no gain, medium dose gave an increase of 50 m3 ha-1 and low dose a growth increase of 100 m3 ha-1 as compared to the control. In order to calculate NUEtree de Vries (2009) assumed a wood density of 500 kg m-3 and C content at 50% to calculate a net C gain of 25, 000 k g C the total N input was also calculated and net C gain was divided by this value to give 25 kg C/kg N for the lowest levels of N application. Model simulations have been used extensively in the literature. Levy et al. (2004) used three models (CENTURY, BCG and Hybrid) that employ a Monte Carlo approach, utilising conceptual algorithms that depend on repeated random sampling to obtain numerical results. The models were applied to a coniferous forest in Sweden for a 100 year period. Simulated nitrogen deposition levels were from data by Schulze (2000) the current ambient nitrogen deposition of 12 kg N ha-1 year-1 or 10 Ãâ€" current ambient nitrogen deposition, 120 kg N ha-1 year-1. Sutton et al. (2008) used the same inputs as Levy et al. (2004) but calculated a smaller value of total N-deposition (6-26 kg N ha-1 yr-1). Milne and Van Oijen (2005) used a complex forest growth model (EFM) directly parameterised to 22 specific sites selected across Europe, because growing conditions such as soil nitrogen levels were available for the sites. Model simulations were run for an 80 year period, control runs maintained N-deposition v alues at their 1920 levels whereas environmental change scenarios ran observed values of change averaging 10.5  ± 5.2 kg N ha-1 yr-1 for the whole period.

14 a day keeps the depression away :: essays research papers

Fourteen a Day Keeps the Depression Away What is Bi- Polar disorder? It is a condition formerly known as Manic Depressive Disorder that involves depressive episodes along with periods of elevated moods known as mania. Symptoms of mania include an abnormally elevated mood, irritability, an overly inflated sense of self-esteem, and distractibility. Persons experiencing an episode of mania are generally talkative, have a decreased need for sleep, and may engage in reckless or risk-taking behaviors. What is it like for a child that is diagnosed with Bi- Polar disorder? One of the many challenges a child with this disease faces is attending school. I have a young person in my life that was diagnosed with this disorder at the age of four and has been on medication since. He is now thirteen and is in the 7th grade. A characteristic of his particular disorder is that his IQ is considered that of a genius and last year in the 6th grade he was even accepted into the Mensa Society. Every morning, afternoon, and evening he is expected to ingest a handful of various mood-stabilizers. He talks to everyone, but more often his self, and stays up all night watching cartoons. He does not have any friends and his medications have caused him to become overweight. Should young children take so much medicine that they need uppers and downers? He has never been removed from them all at once but every few months they take him off one thing and then he starts some new miracle drug. There is no incli nation what kind of person this child would be without medication in his system that alters his emotions and personality. This child has been diagnosed with Bi- Polar disease, ADHD, Obsessive Compulsive Disorder, and Oppostional Defiance Disorder. I ask myself if he really has all these conditions or if all young children get hyper sometimes. He cries because he can’t figure out how to use his vocabulary word in a sentence. He throws a conniption fit when the loops of his shoelaces aren’t tied exactly symmetrical. I have gone back and forth for years trying to determine what he needs. Up to the age of four he would get so frustrated that he would lash out. A cat scan revealed that he has seizures in the frontal lobe of his brain that cause him to become aggravated and sometimes violent.

Vijayawada in the Krishna District of Andhra Pradesh

A quadruplet is a multiplier that is lifted by four rotors. Unlike traditional helicopters, the quadruplet use 2 sets of propellers with 2 clockwise and 2 anti- clockwise. It was first designed by Louis Brute in 1907. It lifted off the ground by using four propellers In four different directions. Although It could only go up for several feet, it was a great step for the development of quadruplets. More than a decade later, in the asses, more engineers and scientists developed their own types f oratorical.Edmond Machine, a French engineer and helicopter designer, successfully designed a multiplier with four rotors that were installed at the ends of four arms. It provided a very high stability at that time and marked a record of 360 meters traveling distance. As time has passed, the quadruplet has changed into different styles and models. In asses-1 sass, the world was undergoing a very rapid economic development. There was a huge demand for transportation of Industrial materials. The quadruplet was a machine that people always prefer to use.However, due to lack improvement of the quadruplet, it was still not adopted for industrial use. In recent years, many small scale quadruplet are widely used in many ways. As there are many advanced airplanes, quadruplets are no longer under consideration as a means to transport people or commodities. Instead, they are used in different areas, like ordnance surveying, rescue support, film taking etc. Nowadays, quadruplets are always equipped with a camera. The data recorded by a quadruplet can be directly sent to a computer or saved in a storage system.During the Chuan earthquake In 2008, landslides blocked miles of country roads and properties. The rescuers could not enter the affected area. Also, airplanes could land or fly over some of these remote areas. The situation in the affected area remained unknown for the rescuers. The quadruplet help people to assess the damage quickly and more accurately in the remote areas. The ID robotics quadruplet, supported by a simple GAPS controlled through a computer, allowed the rescue teams to locate the affected areas.As the quadruplet is small in size and invulnerable, it can travel to very inaccessible places. We no longer need to rely on expensive alternatives like helicopters. Another common application of the quadruplet Is video and film taking. In the old days, if we want to take some scenes in the sky, we would probably need to use an airplane to help us. However, it is very difficult for an airplane to fly between skyscrapers and along narrow streets like In Hong Kong. Yet, but using a quadruplet can help the directors to achieve this goal.Since the quadruplet can be controlled by remote control or through computer programs, people can control their quadruplet to any direction they like. No matter whether you are standing on a cliff, or in I OFF flexibility and effectiveness of film making. The above applications are not those which are common in most pe ople's lives. Many people cannot afford to buy a quadruplet. Even if they could afford one, there are few ways that they could use it. However, in the future, we will have a chance to see hundreds of quadruplets flying over our heads.The world largest online retailer Amazon introduced a new delivery system-?Prime Air. This futuristic system allows customers to get their ordered packages into their hands within half an hour via unmanned aerial vehicles. The specially designed aerial vehicle is based on a prototype of a quadruplet. There are clamps to hold a box under the copter. The aerial vehicle is equipped with and tracked by a very precise GAPS system. It can even direct the copter outside the shopper's doorstep. In the future, the world's population will keep increasing. Land will become more crowded.Other than open up underground areas, the air space is expected to open p when we have better technology capabilities. As online shopping is growing in popularity, the Prime Air not only can boost the efficiency and economic growth, it can greatly reduce the demand for land transportation. To make Prime Air practicable, many weaknesses need to be considered and solved. What people discuss the most is safety. People will probably feel frightened and worried when they see a flying machine whizzing Just ten meters above their heads. People will also wonder whether the clamps strong enough to hold the box without dropping it.Although the copter is tracked by a very accurate GAPS system, there are many physical obstacles like trees, streetlights, advertisements and even construction sites which are not shown or frequently updated in the system. The technologies nowadays may not be capable to direct the unmanned aerial vehicles to keep away from these obstacles. This puts a restriction on sending a copter to crowded and busy areas like Hong Kong or New York. In the meantime, engineers needs to consider other problems like weather, battery life, load capacity and sec urity.A quadruplet for goods delivery use needs some kind f design to protect the electronic components inside it and this type of service would be highly susceptible to the weather conditions. If the quadruplet could only operate on dry days, the whole concept may somewhat lose it's meaning of effective delivery. What's more, there is no one guard the copter. How can we ensure it can safely and accurately fly to the destination? There are still many things need to deal with in the future to make an application like this a reality. In the future, accoutered will be more commonly used in different aspects.

The Dynamics Of Love Toni Morrison s Beloved - 2402 Words

GwonSeob Cha Paper Topic The Dynamics of Love In Toni Morrison’s Beloved â€Å"The need of a love-relationship is the fundamental thing [in life].† (Guntrip 45) Love - possibly one of the most universally known yet personally exclusive emotion felt by man. In merely one word, â€Å"love† is used to express the love between a person and an object, a parental figure and his/her dependent, two people in a platonic relationship, and even the bond between two lovers. Love can also come in a variety of shapes, sizes, and even magnitudes. Throughout her novel, Beloved, Toni Morrison shows a very peculiar sense of love through Sethe’s relationship with Beloved as well as her relationship with Paul D. Although certain accounts may seem as if the love died†¦show more content†¦As Schapiro states earlier, â€Å"The mother, the child s first vital other, is made unreliable or unavailable by a slave system which either separates her from her child or so enervates and depletes her that she has no self with which to confer recognition.â⠂¬  (Schapiro 194), and lastly, Paul D had to personally endure the tragedies of slavery, which involved constant torture and humility. Due to these misfortunes that everyone had to go through, they themselves are unable to recognize their own inner selves. It is here where the problem arises: if the characters themselves do not know themselves, how are they expected to know, or even love one another? Sethe, Beloved, and Paul D all have one thing in common: a lack of memory. In Beloved’s case, she was murdered as an infant and therefore doesn’t own any memories, and in Sethe and Paul D’s case, they have a constant need to forget their memories for the fear of their memories overtaking them. It is specifically these characters’ lack of memory, or self, that helps create this interesting dynamic of love. The love that they share between them, at first is incomplete and rather