of the global biogeochemical cycle of vanadium (V), including both human-derived and natural fluxes. Through mining of V ores (130 × 109 g V/y) and extraction and combustion of fossil fuels (600 × 109 g V/y), humans are the predominant force in the g
Nutrient Cycling 1: The nitrogen cycle I. Introduction A. Changes to the global N cycle (Ch. 15) 1. Global pools and fluxes 2. Changes 3. Consequences B. Overview of the ecosystem N cycle (Ch. 9) 1. Major pools and fluxes 2. Main points II. Controls
Nitrogen Cycle The N cycle illustrates how N from manure, fertilizers and plants moves through the soil to crops, water and the air. Understanding the N cycle
conversion of ammonium to ammonia gas, which is released to the atmosphere. The volatilization losses increase at higher soil pH and conditions that favor evaporation (e.g. hot and windy). Volatilization losses are higher for manures and urea fertili
Lecture 12 – Global Biogeochemical Cycles (1) If rivers are the chief source of the dissolved salts in seawater, why is seawater not simply a concentrated version of average composition of all rivers?
The University of Maine [email protected] Marine Sciences Faculty Scholarship School of Marine Sciences 8-1-2009 Observing Biogeochemical Cycles at Global Scales
Plants and algae can assimilate ammonia and ammonium directly for the ... "There is no end to the nitrogen cycle; ... and nitrogen is no ...
13-1 CHAPTER 13: NITROGEN REMOVAL THE NITROGEN CYCLE Nitrogen, element number seven on the periodic table, is an essential part of living matter and a relatively common element on our planet.
Interesting Nitrogen Cycle Facts: Plants absorb nitrogen directly from the soil. Animals get their nitrogen needs met by eating plants or eating animals that eat plants.
Deg ra dation of amm on ia into nitrite is known as nitrification. ... nitrogen gas which completes the nitrogen cycle. Denitrification is performed by species of ...
Lecture 11. Global biogeochemical cycles of nitrogen and
oxygen. Objectives: 1. Global biogeochemical cycle of nitrogen. 2. Global biogeochemical cycle of oxygen.
Readings: Turco: p. 301-307; Brimblecombe: p. 23-24, 38 (20-41)
1. Global biogeochemical cycle of nitrogen. Principal nitrogen compounds in the atmosphere: N2 , N2O, NO, NO2 , HNO3, NH3
Figure 11.1 The elements of the nitrogen cycle accounting for fertilization.
N2 is extremely stable chemically and is not involved in the chemistry of the troposphere or stratosphere (except atmospheric conditions with high energy, such as lightning).
• N2O is colorless gas (referred to as “laughing gas) emitted almost totally by natural sources.
Table 11.1 Estimated sources and sinks of N2O typical of the last decade (IPCC 1995). Sources Natural Oceans Tropical soils: wet forest dry savannas Temperate soils: forests grasslands Total natural sources Anthropogenic Cultivated soils Biomass burning Industrial sources Cattle and feedlots Total anthropogenic sources Total sources Sinks Stratosphere Soils Total sinks Implied total sources
Range (Tg(N) yr-1)
Likely (Tg(N) yr-1)
0.1-2.0 0.5-2.0 6-12
1 1 9
1.8-5.3 0.2-1.0 0.7-1.8 0.2-0.5 3.7-7.7
3.5 0.5 1.3 0.4 5.7
(atmospheric increase+total sinks)
NOx (NO + NO2) are emitted both by natural and anthropogenic sources.
Table 11.2 Estimated global emissions of NOx typical of last decade (IPCC 1995). Sources
Magnitude (Tg(N)/yr.) Fossil-fuel combustion 24 Soil release (natural and 12 anthropogenic) Biomass burning 8 Lighting 5 NH3 oxidation 3 Aircraft 0.5 Transport from 0.1 stratosphere
Reactive nitrogen, denoted NOy, is defined as the sum of the NOx and all compounds that are products of the atmospheric oxidation of NOx (these include nitric acid, HNO3; nitrous acid, HONO; the nitrate radical, NO3; dinitrogen pentoxide, N2O5; peroxynitric acid, HNO4; peroxyacetyl nitrate, PAN (RC(O)OONO2).
Typical NOy concentrations: in rural areas: 0.07-1 ppb in the remote troposphere: 1-20 ppb
Mean tropospheric residence time for gaseous NOy (including HNO3): 1 to 4 days NOTE: Because of this relatively short atmospheric lifetime, the major effects of emissions of nitrogen oxides are expected to be local or regional rather than global in nature.
• Ammonia is the primary basic gas in the atmosphere and, after N2 and N2O, is the most abundant nitrogen-containing compound in the atmosphere.
Table 11.3 Estimated global ammonia emissions. Emission (Tg(N) yr-1)
Source of Ammonia Natural Wild animals Vegetation Ocean Total natural sources Anthropogenic Dairy cattle Beef cattle Pigs Horses Sheep/goats Poultry Fertilizer Biomass burning Total anthropogenic sources Grand total
Ammonium ions (NH4+) are important component of the tropospheric aerosol.
Mean tropospheric residence time for ammonia: about 10 days (because NH3 is readily absorbed by surfaces such as water and soil) • Nitrogen fixation refers to the chemical conversion of N2 to any other nitrogen compound. For instance, some microorganisms are capable of converting N2 ammonia and ammonium ion.
2. Global biogeochemical cycle of oxygen. Principal oxygen compound in the atmosphere: O2 , O3 •
The source of oxygen in the atmosphere reservoir is CO2: CO2 + H2O under sunlight conditions (photosynthesis) produces oxygen and organic compound.
Figure 11.2 The partitioning of oxygen between the atmosphere and the biosphere, and the role of carbon burial in free oxygen production (Turco 1997).