103 relations: Acid rain, Aeration, Aerosol, Alfalfa, Amino acid, Ammonia, Ammonium, Anaerobic respiration, Anammox, Archaea, Atmosphere, Atmosphere of Earth, Atmospheric chemistry, Azotobacter, Bacteria, Bedrock, Biodiversity, Biogeochemical cycle, Caister Academic Press, Carbohydrate, Carbon dioxide, Catalysis, Catskill Mountains, Chlorophyll, Clostridium, Clover, Combustion, Cyanobacteria, Dead zone (ecology), Decomposition, Denitrification, Deposition (aerosol physics), Diazotroph, Ecology, Ecosystem, Enzyme, Eutrophication, Ferredoxin, Fertilizer, Fossil fuel, Global warming, Greenhouse gas, Groundwater, Haber process, Heath, Heterotroph, High-nutrient, low-chlorophyll regions, Human impact on the environment, Human impact on the nitrogen cycle, Humus, ..., Hydrogen, Hypoxia (environmental), Intensive farming, Ion, Legume, Lightning, Marine ecosystem, Methane, Methemoglobinemia, Microorganism, Mineralization (geology), Mineralization (soil science), Mutualism (biology), Nancy Rabalais, Nitrate, Nitrate reductase, Nitric acid, Nitric oxide, Nitrification, Nitrifying bacteria, Nitrite, Nitrobacter, Nitrogen, Nitrogen cycle, Nitrogen fixation, Nitrogenase, Nitrosomonas, Nitrous oxide, Nucleotide, Oligotroph, Organic compound, Organic matter, Ozone, Photic zone, Phytoplankton, Planetary boundaries, Plant, Point source pollution, Primary production, Prochlorococcus, Pseudomonas, Redox, Rhizobium, Scarcity, Smog, Solubility, Soybean, Stratosphere, Symbiosis, Synechococcus, Terrestrial ecosystem, Troposphere, Urine. Expand index (53 more) » « Shrink index
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH).
Aeration (also called aerification) is the process by which air is circulated through, mixed with or dissolved in a liquid or substance.
An aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas.
Alfalfa, Medicago sativa also called lucerne, is a perennial flowering plant in the pea family Fabaceae cultivated as an important forage crop in many countries around the world.
Amino acids are organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid.
Ammonia is a compound of nitrogen and hydrogen with the formula NH3.
The ammonium cation is a positively charged polyatomic ion with the chemical formula.
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O2).
Anammox, an abbreviation for anaerobic ammonium oxidation, is a globally important microbial process of the nitrogen cycle that takes place in many natural environments.
Archaea (or or) constitute a domain of single-celled microorganisms.
An atmosphere is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body.
The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity.
Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied.
Azotobacter is a genus of usually motile, oval or spherical bacteria that form thick-walled cysts and may produce large quantities of capsular slime.
Bacteria (common noun bacteria, singular bacterium) is a type of biological cell.
In geology, bedrock is the lithified rock that lies under a loose softer material called regolith at the surface of the Earth or other terrestrial planets.
Biodiversity, a portmanteau of biological (life) and diversity, generally refers to the variety and variability of life on Earth.
In geography and Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical substance moves through biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) compartments of Earth.
Caister Academic Press is an independent academic publishing company that produces books and ebooks on microbiology, and molecular biology.
A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water); in other words, with the empirical formula (where m may be different from n).
Carbon dioxide (chemical formula) is a colorless gas with a density about 60% higher than that of dry air.
Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalysthttp://goldbook.iupac.org/C00876.html, which is not consumed in the catalyzed reaction and can continue to act repeatedly.
The Catskill Mountains, also known as the Catskills, are a physiographic province of the larger Appalachian Mountains, located in southeastern New York.
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and the chloroplasts of algae and plants.
Clostridium is a genus of Gram-positive bacteria, which includes several significant human pathogens, including the causative agent of botulism and an important cause of diarrhea, Clostridium difficile.
Clover or trefoil are common names for plants of the genus Trifolium (Latin, tres "three" + folium "leaf"), consisting of about 300 species of plants in the leguminous pea family Fabaceae.
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.
Cyanobacteria, also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen.
Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes, caused by "excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water.
Decomposition is the process by which organic substances are broken down into simpler organic matter.
Denitrification is a microbially facilitated process where nitrate is reduced and ultimately produces molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products.
In aerosol physics, deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air.
Diazotrophs are bacteria and archaea that fix atmospheric nitrogen gas into a more usable form such as ammonia.
Ecology (from οἶκος, "house", or "environment"; -λογία, "study of") is the branch of biology which studies the interactions among organisms and their environment.
An ecosystem is a community made up of living organisms and nonliving components such as air, water, and mineral soil.
Enzymes are macromolecular biological catalysts.
Eutrophication (from Greek eutrophos, "well-nourished"), or hypertrophication, is when a body of water becomes overly enriched with minerals and nutrients that induce excessive growth of plants and algae.
Ferredoxins (from Latin ferrum: iron + redox, often abbreviated "fd") are iron-sulfur proteins that mediate electron transfer in a range of metabolic reactions.
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin (other than liming materials) that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants.
A fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis.
Global warming, also referred to as climate change, is the observed century-scale rise in the average temperature of the Earth's climate system and its related effects.
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range.
Groundwater is the water present beneath Earth's surface in soil pore spaces and in the fractures of rock formations.
The Haber process, also called the Haber–Bosch process, is an artificial nitrogen fixation process and is the main industrial procedure for the production of ammonia today.
A heath is a shrubland habitat found mainly on free-draining infertile, acidic soils and is characterised by open, low-growing woody vegetation.
A heterotroph (Ancient Greek ἕτερος héteros.
High-nutrient, low-chlorophyll (HNLC) regions are regions of the ocean where the abundance of phytoplankton is low and fairly constant despite the availability of macronutrients.
Human impact on the environment or anthropogenic impact on the environment includes changes to biophysical environments and ecosystems, biodiversity, and natural resources caused directly or indirectly by humans, including global warming, environmental degradation (such as ocean acidification), mass extinction and biodiversity loss, ecological crises, and ecological collapse.
Human impact on the nitrogen cycle is diverse.
In soil science, humus (derived in 1790–1800 from the Latin humus for earth, ground) denominates the fraction of soil organic matter that is amorphous and without the "cellular cake structure characteristic of plants, micro-organisms or animals." Humus significantly affects the bulk density of soil and contributes to its retention of moisture and nutrients.
Hydrogen is a chemical element with symbol H and atomic number 1.
Hypoxia refers to low oxygen conditions.
Intensive farming involves various types of agriculture with higher levels of input and output per cubic unit of agricultural land area.
An ion is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons).
A legume is a plant or its fruit or seed in the family Fabaceae (or Leguminosae).
Lightning is a sudden electrostatic discharge that occurs typically during a thunderstorm.
Marine ecosystems are among the largest of Earth's aquatic ecosystems.
Methane is a chemical compound with the chemical formula (one atom of carbon and four atoms of hydrogen).
Methemoglobinemia is a condition caused by elevated levels of methemoglobin in the blood.
A microorganism, or microbe, is a microscopic organism, which may exist in its single-celled form or in a colony of cells. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from 6th century BC India and the 1st century BC book On Agriculture by Marcus Terentius Varro. Microbiology, the scientific study of microorganisms, began with their observation under the microscope in the 1670s by Antonie van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera and anthrax. Microorganisms include all unicellular organisms and so are extremely diverse. Of the three domains of life identified by Carl Woese, all of the Archaea and Bacteria are microorganisms. These were previously grouped together in the two domain system as Prokaryotes, the other being the eukaryotes. The third domain Eukaryota includes all multicellular organisms and many unicellular protists and protozoans. Some protists are related to animals and some to green plants. Many of the multicellular organisms are microscopic, namely micro-animals, some fungi and some algae, but these are not discussed here. They live in almost every habitat from the poles to the equator, deserts, geysers, rocks and the deep sea. Some are adapted to extremes such as very hot or very cold conditions, others to high pressure and a few such as Deinococcus radiodurans to high radiation environments. Microorganisms also make up the microbiota found in and on all multicellular organisms. A December 2017 report stated that 3.45 billion year old Australian rocks once contained microorganisms, the earliest direct evidence of life on Earth. Microbes are important in human culture and health in many ways, serving to ferment foods, treat sewage, produce fuel, enzymes and other bioactive compounds. They are essential tools in biology as model organisms and have been put to use in biological warfare and bioterrorism. They are a vital component of fertile soils. In the human body microorganisms make up the human microbiota including the essential gut flora. They are the pathogens responsible for many infectious diseases and as such are the target of hygiene measures.
In geology, mineralization is the deposition of economically important metals in the formation of ore bodies or "lodes" by various process.
Mineralization in soil science is the decomposition, i. e. oxidation, of the chemical compounds in organic matter, by which the nutrients in those compounds are released in soluble inorganic forms that may be available to plants.
Mutualism or interspecific cooperation is the way two organisms of different species exist in a relationship in which each individual benefits from the activity of the other.
Nancy N. Rabalais is an American marine ecologist.
Nitrate is a polyatomic ion with the molecular formula and a molecular mass of 62.0049 u.
Nitrate reductases are molybdoenzymes that reduce nitrate (NO) to nitrite (NO).
Nitric acid (HNO3), also known as aqua fortis (Latin for "strong water") and spirit of niter, is a highly corrosive mineral acid.
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula NO.
Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate.
Nitrifying bacteria are chemolithotrophic organisms that include species of the genera Nitrosomonas, Nitrosococcus, Nitrobacter and Nitrococcus.
The nitrite ion, which has the chemical formula, is a symmetric anion with equal N–O bond lengths.
Nitrobacter is a genus comprising rod-shaped, gram-negative, and chemoautotrophic bacteria.
Nitrogen is a chemical element with symbol N and atomic number 7.
The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrial, and marine ecosystems.
Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia (NH3) or other molecules available to living organisms.
Nitrogenases are enzymes that are produced by certain bacteria, such as cyanobacteria (blue-green algae).
Nitrosomonas is a genus of Gram-negative rod-shaped chemoautotrophic bacteria.
Nitrous oxide, commonly known as laughing gas or nitrous, is a chemical compound, an oxide of nitrogen with the formula.
Nucleotides are organic molecules that serve as the monomer units for forming the nucleic acid polymers deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth.
An oligotroph is an organism that can live in an environment that offers very low levels of nutrients.
In chemistry, an organic compound is generally any chemical compound that contains carbon.
Organic matter, organic material, or natural organic matter (NOM) refers to the large pool of carbon-based compounds found within natural and engineered, terrestrial and aquatic environments.
Ozone, or trioxygen, is an inorganic molecule with the chemical formula.
The photic zone, euphotic zone (Greek for "well lit": εὖ "well" + φῶς "light"), or sunlight or (sunlit) zone is the uppermost layer of water in a lake or ocean that is exposed to intense sunlight.
Phytoplankton are the autotrophic (self-feeding) components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems.
Planetary boundaries is a concept of nine Earth system processes which have boundaries proposed in 2009 by a group of Earth system and environmental scientists led by Johan Rockström from the Stockholm Resilience Centre and Will Steffen from the Australian National University.
Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae.
A point source of pollution is a single identifiable source of air, water, thermal, noise or light pollution.
Global oceanic and terrestrial photoautotroph abundance, from September 1997 to August 2000. As an estimate of autotroph biomass, it is only a rough indicator of primary-production potential, and not an actual estimate of it. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE. In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide.
Prochlorococcus is a genus of very small (0.6 µm) marine cyanobacteria with an unusual pigmentation (chlorophyll ''a2'' and ''b2'').
Pseudomonas is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 validly described species.
Redox (short for reduction–oxidation reaction) (pronunciation: or) is a chemical reaction in which the oxidation states of atoms are changed.
Rhizobium is a genus of Gram-negative soil bacteria that fix nitrogen.
Scarcity refers to the limited availability of a commodity, which may be in demand in the market.
Smog is a type of air pollutant.
Solubility is the property of a solid, liquid or gaseous chemical substance called solute to dissolve in a solid, liquid or gaseous solvent.
The soybean (Glycine max), or soya bean, is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses.
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.
Symbiosis (from Greek συμβίωσις "living together", from σύν "together" and βίωσις "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic.
Synechococcus (from the Greek synechos, in succession, and the Greek kokkos, granule) is a unicellular cyanobacterium that is very widespread in the marine environment.
A terrestrial ecosystem is a type of ecosystem found only on biomes also known as beds.
The troposphere is the lowest layer of Earth's atmosphere, and is also where nearly all weather conditions take place.
Urine is a liquid by-product of metabolism in humans and in many animals.