Climatic and lithogenic controls on soil organic matter-mineral associations.

Climatic and lithogenic controls on soil organic matter-mineral associations. Interactions of organic matter (OM) with soil mineral phasesstrongly affect the storage and dynamics of soil OM as well as otherecosystem processes. This study examined aspects of organo-mineralassociations in soils at different scales. First, I assessed thepotential controls of climate and parent rock type on organo-mineralassociations using two sets of undisturbed tropical forest soilsdeveloped on two contrasting rocks along an altitudinal gradient inBorneo, Southeast Asia. Density fractionations showed that OM stored insurface mineral soils partitioned towards plant detritus fraction undercooler climates on both rock types. Thus climate exerted strongercontrol on soil OM storage and partitioning patterns than parent rock inthe study area. The plant detritus associated with soil mineral grainsalso increased its standing stock under cooler climates, suggesting thatabundance of mineral-free detritus and its comminution comminution (kˈ·m had strongercontrol than soil mineralogical min��er��al��o��gy?n. pl. min��er��al��o��gies1. The study of minerals, including their distribution, identification, and properties.2. A book or treatise on mineralogy. factors. Second, gas sorption sorption/sorp��tion/ (sorp��shun) the process or state of being sorbed; absorption or adsorption. sorp��tionn.Adsorption or absorption. approacheswere applied to the same sets of soils to assess OM associations withsoil mineral surfaces. Surface characterization before and after OMremoval revealed that, with increasing altitude and OM loading, OMappear to accumulate in globular globularresembling a globe.globular hearta spherical cardiac silhouette, usually greatly enlarged and lacking the detailed outline of the right and left atria and apex. Characteristic of pericardial effusion and cardiomyopathy. forms that incidentally encapsulatefine mineral grains, rather than accumulating via sorption onto allmineral surfaces. Similar control of soil OM loading on theorgano-mineral arrangements was found in soils of different geographicareas and soil types (n = 33), suggesting much wider generality of thisrelationship. Third, I examined the importance of hydrous iron oxides Hydrous iron oxides, also called hydrous ferric oxides, are a class of minerals that form from the weathering of minerals that contain iron (Fe) and hydroxides (OH-), but not water. They are poorly crystalline, highly porous and have large surface areas. (FeOx), a common soil mineral phase known to have strong sorptivecapacity, for soil OM storage using a wider range of mineral soilsspanning eight soil orders. With a modified selective FeOx dissolutionmethod, I achieved the first quantification of the organic carbon (OC)that can be released from FeOx phases. Iron-bound OC accounted for onlyminor fractions of total soil OC (mean: 11%, range: 0-37%), indicatinglimited capacity of FeOx to sorptively store bulk of soil OM. The massratios of OC to iron (OC:Fe) of the extracts in some low pH, organicsamples (e.g., spodic horizons) implied the presence of organo-ironcomplexes rather than adsorbed forms. (Winzeler database) Ph.D. thesis (Biogeochemistry bi��o��ge��o��chem��is��try?n.The study of the relationship between the geochemistry of a region and the animal and plant life in that region.bi , Soil sciences, Ecology), Universityof Maine "UMO" redirects here, but this abbreviation is also used informally to mean the Mozilla Add-ons website, formerly Mozilla UpdateShould not be confused with Universit�� du Maine, in Le Mans, FranceThe University of Maine .