It is proposed here that the laterization of tropical soils, whereby silica is leached out to leave iron and aluminum hydroxides behind, is caused by a high alkalinity past the mid gut of soil eating termites. It is suggested that this alkalinity first arose primarily in order to make phosphate available to the termites and it resulted in laterites, bauxites, glauconite, and diatom rise especially in early Cretaceous
The humus eating termites, which make up over half of the termite species [Brune & Kuhl, 1996], must have to solve the problem of binding of phosphorus by iron and aluminum in soil. They may have done this by creating an alkaline medium in their gut. The humus eating termites create an alkaline pH of 11 to 12.5 just past the mid gut-hindgut junction (the P1 segment) [Bignell, 1998 (there are diagrams of the various gut designs of termites here)]. It is said that this is the highest pH in the biological world. It was obtained using micro electrodes, so is probably accurate [Brune & Kuhl, 1996]. This is 100,000 times as many hydroxyl ions as in a neutral solution, the equivalent of a solution of potassium lye. To put this in perspective, a tenth normal solution of potassium carbonate has a pH of 11.6, a tenth normal solution of potassium silicate has a pH of 12.6, saturated lime (calcium hydroxide) has a pH of 12.4, and a one hundredth normal solution of potassium hydroxide (potassium lye) has a pH of 12. A 200 mM (one fifth normal) solution of potassium carbonate mimics the pH of the gut's P1 region [Kappler].
They must be doing it by removing all the carbonate and plant acid anions and leaving behind the potassium ions or by removing potassium from rectum of the hind gut, which has a pH of 5.0, and transferring it to the P-1 segment. Potassium is the dominant cation in the gut fluid of Zootermopsis. Such a high pH would tend to displace phosphate from the iron [Dixon p414] and aluminum and make it available to be absorbed. Brune and Kuhl (1996) suggest that the reason for the high pH is to enable termites to digest soil bacteria and/or to make polyphenolic compounds soluble and unable to bind peptide nitrogen compounds. This is plausible since wood eating termites have a high pH also and Lepidoptera and Diptera larvae that eat leaves and detritus have a high pH also [Brune and Kuhl, 1996]. Apparently termites can degrade lignin somewhat [Brune, Miambi, & Breznak, ]. This may add to the desirability of a high intestinal pH to termites, but I suggest the main imperative is to make phosphate soluble in eaters of soil humus. Sodium hydroxide is the best extracting medium of phosphate from soil [Cade-Menum ] and the hydroxide ion is a strong competitor for aluminum compared to others even phosphate and fluoride [Dixon p366]. Phosphate adsorbed on goethite (Fe OOH) has a steep decline after a pH of 8.0 to almost zero [Dixon p414].
Like the phosphate, the silicate of the soils would also tend to be displaced to form sodium silicate. The fore gut and rectum are acid. So the silicate must become the hydroxide and become very small colloids before it is excreted. Silicon hydroxide formed should be much more soluble than parent materials, and may even be able to move down through the soil in the form of small colloids, which are probably formed when the potassium silicate reaches the hind gut, especially if protected by organic anions. This may be the reason why tropical soils have the silica leached out of them. It could also explain the formation of silicretes and opals deep in Australian Tertiary savanna soils, silica for which arise from dissolution at the top [Thiry p733]. Weathering and leaching proceeds to greater depths when rainfall is concentrated in a short period [Dixon p361]. This, then, would explain the laterization of tropical soils. Schaefer has linked termites to latisols in South America because of the microcrystalline similarity to soil of termite mound material [Schaefer]. It would also explain the large deposits of bauxite (aluminum hydroxide) characteristic of some of them from the appropriate parent materials. Bauxite tends to be low in iron when subjected to constant rainfall [Dixon p361]. Bauxite probably remains intact in the middle soil profile because it is friable and therefore not suitable for cementing together sand particles. The termites bore down past the bauxite to the lower part of the profile to where the kaolin clay is in order to build their nests and runways in Australia, probably because the bauxite is friable and does not make strong construction. So it appears that some species move silicon up to the surface of the soil. These soils used to be called latisols, but are called oxisols and ultisols by the USDA and ferralsols or acrisols by the UN these days. There would be plenty of time for the leaching to take place because humivorus (eat humus) termites do not usually make above ground runways [Kooyman] as compared to the short time that erosion susceptible Amitermitinae (now called Termitinae) soils probably linger. It could also account for the source of the silicate to form the deposits of marine glauconite (green sand or iron silicate) laid down starting around early Cretaceous. and account for the rise in diatom diversity that commenced then [Miller 2005, diagram on p1294]. Diatoms are algae with a silica skeleton. The sediments in the North American interior sea way averaged 81% silica in the (Campanian) [Young]. Most of it was thought to be from diatoms, but some from sponges and radiolarians. It is primarily in the form of cristabolite (64%).
It is possible that some of the ancient soil eating roaches and wood roaches had the beginnings of such an attribute and thus account for the red beds which started in early Permian in South Africa, and in mid Permian in Europe, North America and Argentina [Veevers, et al]. In the Permian it was not necessarily humus eating wood roaches, but could have been humus eating cockroaches. The anaerobic reducing conditions in part of the termite gut may have assisted this process by reducing the iron in the minerals to the ferrous form [Vu], which oxidized to the ferric form upon reaching the soil, and could conceivably have contributed to red bed formation even with less of an alkaline gut. The soils of early Triassic were said to have no modern parallels, although some Madagascar soils may be fairly close. They were extremely low in organic matter and had no detritus. There was much less podzolization (or lacked podosols), although iron did migrate down to precipitate as iron carbonate [Retallack 1997]. Laterites or soils high in iron oxides are thought to have formed as early as the Triassic in north Australia [Twidale p170]. Since termites probably existed by that time [Emerson 1955 p476], ascribing laterites to termites is tentatively supported by paleontology. Laterites were widespread by the Cretaceous.
It has been proposed that the roots of plants remove silicon from the B horizon (soil below the top soil) of the soil and add it to the A horizon to form kaolin from the gibbsite clay [Lucas]. This is plausible, but I suspect that they were able to use more efficiently subsoil silicon because it had already been solubilized by the termites. It used to be proposed that tropical silica dissolved in the tropics because of high soil temperatures. However, silica solubility is independent of temperature between 0 and 200 degrees centigrade between a pH between 2 and 9.5 [Stever]. Do not feel that termites are not numerous enough to have had such an effect. Even in today's world kept in check by ants they transpire 2% of the world's carbon dioxide and 4% of the world's atmospheric methane [Sanderson], even though they are largely confined to tropical areas, and they were almost certainly much more numerous in the past. They are responsible for eating almost as much vegetation in their areas as vertebrates [Wood & Sands p280] and are the chief consumers in southwest USA range lands [Whiteford]. There can be over a kilogram of termites in a square meter in some areas [Eggleton].
REFERENCES are below
Did the Wood Roach Cause the Permian - Triassic Coal Hiatus?: Digestion of cellulose by the wood roach may have reduced soil litter and enabled the rise of conifers in the Permian.
The Battles of Termites with Ants: The ability of Amitermitinae to smother plants with phosphorus rich runways may have caused a phosphorus famine in the Cretaceous.
Cretaceous Termites and Soil Phosphorus: Removal of soil phosphorus by erosion of termite runways may have resulted in changes in vertebrate bone evolution and explain animal sizes and shapes in our world.
Evolution of Angiosperm Trees: Angiosperm trees migrated across Western Pacific atolls and were made additionally successful by termites.
LINKS TO MARS GEOLOGY
The Canyons of Mars as Erosion by Rivers of Silicone Dust
---- For a hypothesis that explains the large volcanoes of Mars and the bulges associated with them. They are proposed as the disruption from the antipode (opposite side of a sphere) of a huge meteorite or comet impact.
Climate warming as caused by denudation of soil.
----For a site that proposes a thin plate hypothesis to explain the plates in the crust of the earth, see this site. It has a link that explains the formation of ocean trenches.
----For a site that proposes disruption of the crust on Earth at the antipode (opposite side of a sphere) to produce massive lava flows.
SOME USEFUL INTERNET FEATURES
There is a free browser called Firefox, which is said to be less susceptible to viruses or crashes, has many interesting features, imports information from Iexplore while leaving Iexplore intact. You can also install their emailer. A feature that lists all the URLs on a viewed site can be useful when working on your own site.
There is a tool bar by Google that enables you to search the internet from the page viewed, mark desired words, search the site, give page rank, etc.
There is a free program available which tells on your site what web site accessed your site, which search engine, statistics about which country, statistics of search engine access, keywords used and their frequency. It can be very useful.
SOME UNRELATED HEALTH SITES
You may obtain a book about potassium nutrition at this site, along with the table of contents and first chapter. It discusses how food processing, diuretics, diarrhea, enemas, laxatives, corticosteroids, poisons, and disease states cause a deficiency and how potassium will cure heart disease, rheumatoid arthritis, gout, and hypertension. It also discusses procedures to cope with too high a blood potassium and abnormal potassium in diabetes.
Copper Response in Rheumatoid Arthritis: Nutrition and physiology of copper, especially relating to hemorrhoids, aneurysm, herniated discs, anemia, emphysema, and gray hair.
The Purpose of Cortisol: Cortisol is presented as an immune hormone used to defend against diarrhea
Cashew Nuts to Cure Tooth Abscess: Anacardic acids in raw cashew nuts may cure tooth abscesses and possibly gram positive diseases such as acne and leprosy.
Observations on Diabetes: Diabetes may be caused by a poison in food.
A review of what is known about chronic fatigue syndrome.Cronic Fatigue Syndrome
Fluoride in city water will cause fluorosis discoloration of teeth, weakened bones, damage to the kidneys and immune system, bone cancer and, worst of all, damage to the nerves resembling Alzheimer’s disease.
The Eve Controversy: A proposal as to why the human species seems to be derived from a single couple.
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