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sulphur and phosphorus cycle, introduction, process, importance, application, advantage, disadvantage

Sulfur and phosphorus cycle, process, importance, human impact, application, advantage, disadvantage.

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SULFUR AND PHOSPHORUS CYCLE
VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMAN Veerachipalayam-637 303,Sankagiri,Salem Dt, Tamilnadu,India. Affiliated to Periyar University Salem ; recognised under section 2(f)&12(b) of the UGC act,1956 DEPARTMENT OF MICROBIOLOGY TITLE : SULFUR AND PHOSPHORUS CYCLES SUBJECT INCHARGE : Dinesh Kumar Dr. R, Head Of the Department Department of Microbiology. SUBMITTED BY : Nandhini Vengadachalam II M.sc Microbiology Department of Microbiology. SUBJECT : SOIL AND ENVIRONMENTAL MICROBIOLOGY
Content ■ Introduction ■ Sulfur cycle ■ Phosphorus cycle ■ Process ■ Importance ■ Human impact ■ Application ■ Advantage ■ Disadvantage ■ Reference
INTRODUCTION ■ Nature of elements transported in biogeochemical cycles When living organisms die and decay, their body structures disintegrate and may be reduced to constituent molecules. ■ Depending on the region where disintegration of the organisms occurred, the component molecular elements then join the biogeochemical cycle. ■ Elements transported in the biogeochemical cycles have been categorized as, 1.Micro elements 2.Macro elements
1. Micro elements – these are elements required by living organisms in smaller amounts. Examples of such elements include boron used mainly by green plants, copper used by some enzymes and molybdenum used by nitrogen-fixing bacteria. 2. Macro elements – these are elements required by living organisms in larger amounts. Examples of such elements include carbon, hydrogen, oxygen, nitrogen, phosphorous, sulfur.Macro elements are the commonly cited examples of elements that constitute major biogeochemical cycles. The molecules may be further reduced to ionized or hydrated ions in aqueous solutions or to ions in the atmosphere.
SULFUR CYCLE ■ Sulfur (S) is a yellow, non-metallic chemical element with atomic number 16 and the chemical symbol S. It is an essential element for all living organisms because it is a component of proteins, vitamins, and enzymes. ■ The Sulfur cycle is a biogeochemical cycle in which sulfur moves continuously between the atmosphere, lithosphere (rocks and soil), hydrosphere (water), and biosphere (living organisms). ■ Sulfur is an essential macronutrient required for the synthesis of amino acids (cysteine and methionine), proteins, vitamins (biotin and thiamine), coenzymes, and enzymes. ■ Microorganisms play a major role in converting sulfur into different chemical forms, making it available for plants and other organisms.
SULFUR CYCLE PROCESS The process of sulphur cycle is a : The sulphur is released by the weathering of rocks. Sulphur comes in contact with air and is converted into sulphates. Sulphates are taken up by plants and microbes and are converted into organic forms. The organic form of sulphur is then consumed by the animals through their food and thus sulphur moves in the food chain. When the animals die, some of the sulphur is released by decomposition while some enter the tissues of microbes. ■ There are several natural sources such as volcanic eruptions, evaporation of water, and breakdown of organic matter in swamps, that release sulphur directly into the atmosphere. This sulphur falls on earth with rainfall.
PROCESS Sulfur cycle involved process is a, Assimilation l Mineralization l oxidation l
ASSIMILATION Plants and microorganisms absorb sulfate (SO ² ) from the soil ₄ ⁻ and convert it into sulfur-containing amino acids (cysteine and methionine) and proteins. Process - Sulfate released from weathered rocks enters the soil. Plant roots absorb sulfate. Reaction : SO ² → Organic sulfur ₄ ⁻ Example ; ■ Mycorrhizae fungi (Glomus spp.), Plant growth-promoting rhizobacteria (Pseudomonas, Bacillus),Cyanobacteria (Anabaena, Nostoc)
MINERALIZATION Mineralization (Decomposition )Dead plants, animals, and organic wastes are decomposed by microorganisms, releasing sulfur as hydrogen sulfide (H S). Reaction : ₂ Organic sulfur → H S ₂ Process Organic matter is broken down. Sulfur-containing proteins are degraded. H S is released into soil or water. ₂ Example : ■ Bacillus, Pseudomonas, Clostridium, Proteus,Aspergillus, Penicillium
OXIDATION Sulfur-oxidizing bacteria convert hydrogen sulfide (H S) or ₂ elemental sulfur (S) into sulfate (SO ² ). ₄ ⁻ Process H S is oxidized to elemental sulfur. Elemental sulfur is further ₂ oxidized to sulfate. Sulfate becomes available again for plants. Reaction H S → S → SO ² ₂ ₄ ⁻ Example : ■ Acidithiobacillus thiooxidans , Acidithiobacillus ferredoxins,
REDUCTION In Oxygen-deficient (anaerobic) environments, sulfate-reducing bacteria convert sulfate into hydrogen sulfide (H S). ₂ Process Occurs in waterlogged soils, sediments, marshes, and sewage. Bacteria use sulfate instead of oxygen for respiration. H S is released into the environment. ₂ Reaction : SO ² → H S ₄ ⁻ ₂ Example : ■ Desulfovibrioesulfotomaculum,Desulfobacter, Desulfococcus
HUMAN IMPACT WITH SULFUR CYCLE
IMPORTANCE OF SULFUR CYCLE Maintains sulfur balance in nature. Supplies sulfur for plant growth. Essential for protein and amino acid synthesis. Improves soil fertility. Supports microbial diversity. Helps in decomposition of organic matter. Maintains ecosystem productivity. Plays a role in climate regulation. Supports aquatic and terrestrial ecosystems. ■ Maintains nutrient cycling
PHOSPHORUS CYCLE ■ Phosphorus (P) is a limiting nutrient for terrestrial biological productivity, and thus it commonly plays a key role in net car- bon uptake in terrestrial ecosystems. ■ The cycling of P in soils has received much attention, in terms of both fertilization and the natural development of ecosystems. ■ Of the approximately 122,600 Tg P within the soil /biota system on the continents, nearly 98% is held in soils in a variety of forms. ■ The most significant weathering source for phosphorus in soils are apatite minerals.
PHOSPHORUS CYCLE PROCESS ■ The weathering of phosphate rocks, which releases phosphate into the soil and water. Plants absorb this phosphate and incorporate it into organic compounds. ■ Animals obtain phosphorus by consuming plants or other animals. ■ When organisms die or excrete waste, decomposer microorganisms convert organic phosphorus back into inorganic phosphate, returning it to the soil and water. ■ Some phosphate is transported to rivers and oceans, where it forms sediments that eventually become phosphate rocks. Geological uplift exposes these rocks, and the cycle continues.
Steps of phosphorus cycle: Weathering l Absorption by Plants l Absorption by Animals l Return to the Environment through Decomposition PROCESS:
WEATHERING The phosphorus cycle begins with phosphate-rich rocks. Weathering by rain, wind, temperature changes, and flowing water breaks down the rocks. Phosphate ions (PO ³ ) are released into the soil and water. ₄ ⁻ Phosphate-solubilizing microorganisms help make insoluble phosphate available. ■ Microorganisms: Bacillus megaterium, Pseudomonas fluorescens, Aspergillus niger, Penicillium spp.
PLANT UPTAKE (ASSIMILATION) Plants absorb phosphate ions from the soil through their roots. Mycorrhiza fungi increase phosphorus absorption by extending the root surface area. Phosphorus is used to synthesize ATP, DNA, RNA, phospholipids, and nucleic acids. ■ Microorganisms: Arbuscular mycorrhiza fungi (Glomus spp.), Rhizobium spp.
ABSORPTION OF ANIMALS ■ The animals absorb phosphorus from the plants or by consuming plant-eating animals. The rate of the phosphorus cycle is faster in plants and animals when compared to rocks. ■ When the plants and animals die they are decomposed by microorganisms During this process, the organic form of phosphorus is converted into the inorganic form, which is recycled to soil and water. ■ Soil and water will end up in sediments and rocks, which will again release phosphorus by weathering. Thus, the phosphorus cycle starts over. Bacillus spp.Aspergillums spp.Ruminococcus spp.Fibrobacter succinogenes , Prevotella spp.
DECOMPOSITION Dead plants, animals, and wastes are decomposed. Organic phosphorus is converted back into inorganic phosphate and returned to the soil and water. ■ Microorganisms involved: Bacillus spp., Pseudomonas spp., Streptomyces spp., Aspergillus spp., Penicillium spp. ■ When the plants and animals die they are decomposed by microorganisms During this process, the organic form of phosphorus is converted into the inorganic form, which is recycled to soil and water.
HUMAN IMPACT WITH PHOSPHORUS CYCLE
IMPORTANCE PHOSPHORUS CYCLE Essential nutrient: Phosphorus is required for the formation of DNA, RNA, ATP, and phospholipids in living organisms. Plant growth: It helps in root development, flowering, seed formation, and crop productivity. Energy transfer: Phosphorus is a major component of ATP, which provides energy for cellular activities. Bone and teeth formation: It combines with calcium to form calcium phosphate in animals. ■ Maintains ecosystem balance: Recycling of phosphorus maintains soil fertility and nutrient availability.
APPLICATION Maintains soil fertility by recycling sulfur. ■ Used in agriculture for healthy crop growth. ■ Sulfur-oxidizing and sulfur-reducing bacteria are used in bioremediation of polluted soils and wastewater. ■ Helps in the production of sulfur-containing amino acids (cysteine and methionine). ■ Used in agriculture to improve plant growth and crop production. ■ Phosphate-solubilizing microorganisms are used as biofertilizers. ■ Supports production of ATP, DNA, RNA, and phospholipids. ■ Helps maintain nutrient balance in ecosystems.
ADVANTAGE Recycles sulfur naturally. Improves soil fertility and crop yield. Supports protein and enzyme synthesis. ■ Maintains ecosystem stability. ■ Promotes root growth, flowering, and seed formation. ■ Essential for ATP, DNA, RNA, bones, and teeth.
DISADVANTAGE Excess sulfur dioxide (SO ) causes acid rain. ₂ Acid rain damages forests, crops, and aquatic life. Air pollution from burning fossil fuels. Soil and water acidification. ■ Disturbs the natural sulfur balance. ■ Algal blooms reduce dissolved oxygen in water. ■ Fish kills and loss of aquatic biodiversity. ■ Phosphate rock mining depletes natural resources.
REFERENCE Brock Biology of Microorganisms Authors: Michael T. Madigan, Kelly S. Bender, Daniel H. Buckley, W. Matthew Sattley, David A. StahlPublisher: Pearson , Prescott’s Microbiology Authors: Joanne M. Willey, Linda M. Sherwood, Christopher J. Woolverton ,Publisher: McGraw-Hill Environmental Microbiology ■ Publisher: Academic Press ,Environmental Science , Publisher: Cengage Learning
sulphur and phosphorus cycle, introduction, process, importance, application, advantage, disadvantage