on 11-Sep-2020 (Fri)

Nitrogen can be fixed by lightning that converts nitrogen and oxygen into NOx (nitrogen oxides). NOx may react with water to make nitrous acid or nitric acid, which seeps into the soil, where it makes nitrate, which is of use to plants. Nitrogen in the atmosphere is highly stable and nonreactive due to the triple bond between atoms in the N₂ molecule.^[7] Lightning produces enough energy and heat to break this bond^[7] allowing nitrogen atoms to react with oxygen, forming NO_x . These compounds cannot be used by plants, but as this molecule cools, it reacts with oxygen to form NO₂ .^[8] This molecule in turn reacts with water to produce HNO₃ (nitric acid), or its ion NO ⁻₃ (nitrate), which is usable by plants

Guano (Spanish from Quechua: wanu) is the accumulated excrement of seabirds and bats. As a manure, guano is a highly effective fertilizer due to its exceptionally high content of nitrogen, phosphate, and potassium: key nutrients essential for plant growth. Guano was also, to a lesser extent, sought for the production of gunpowder and other explosive materials.

Guano is ecologically important due to its role in dispersing nutrients. Cave ecosystems, in particular, are often wholly dependent on bats to provide nutrients via their guano, which supports bacteria, fungi, invertebrates, and vertebrates. The loss of bats from a cave can result in the extinction of species that rely on their guano. Guano also has a role in shaping caves, as its high acidity results in erosion.

Some natural solid substances without a definite crystalline structure, such as opal or obsidian, are more properly called mineraloids.^[4] If a chemical compound may occur naturally with different crystal structures, each structure is considered a different mineral species. Thus, for example, quartz and stishovite are two different minerals consisting of the same compound, silicon dioxide.

The concept of mineral is distinct from rock, any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral, or may be an aggregate of two or more different types of minerals, spacially segregated into distinct phases.^[3]

The geological definition of mineral normally excludes compounds that occur only in living beings. However some minerals are often biogenic (such as calcite) or are organic compounds in the sense of chemistry (such as mellite). Moreover, living beings often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks.

In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure, that occurs naturally in pure form.^[1].^[2]

Nitro compounds are organic compounds that contain one or more nitro functional groups (−NO₂). The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally. The nitro group is also strongly electron-withdrawing. Because of this property, C−H bonds alpha (adjacent) to the nitro group can be acidic

Nitro groups are rarely found in nature, being almost invariably produced by nitration reactions starting with nitric acid

Scientists Ott et al.^[12] estimated that each flash of lightning on average in the several mid-latitude and subtropical thunderstorms studied turned 7 kg (15 lb) of nitrogen into chemically reactive NO
x . With 1.4 billion lightning flashes per year, multiplied by 7 kilograms per lightning strike, they estimated the total amount of NO
x produced by lightning per year is 8.6 million tonnes. However, NO
x emissions resulting from fossil fuel combustion are estimated at 28.5 million tonnes.^[13]

In addition to portraits and lyrical genre scenes, Cameron also participated in another of photography’s earliest genres: ethnographic images. The emergence of photography coin- cided with the expansion of colonialism by European coun- tries, especially Britain and France. This imperialism mani- fested itself culturally in the form of Orientalism: Western representations—literary and visual—of the Near East,