Photoautotrophs ( Photoautotrophs are autotrophs that use light as a source of energy to make organic molecules) like plants, cyanobacteria, and algae make a large proportion of the Earth’s organic molecules via photosynthesis, using light energy, carbon dioxide (CO2) in the atmosphere, and water (H2O). During this process, they also produce oxygen (O2). To supply their energy needs, both photoautotrophs and heterotrophs ( Heterotrophs must consumefood—organic molecules from their environment ) metabolize organic molecules via cellular respiration. Cellular respiration generates carbon dioxide and water and is used to make ATP ( the energy currency in the cell ). Oxygen is released into the atmosphere and can be reused by photoautotrophs to make more organic molecules such as glucose. In this way, an energy cycle between photosynthesis and cellular respiration sustains life on our planet. 5
Following biogeochemical Cycles are essential for advanced life on earth:
Hydrologic Cycle (Water Cycle)
Global Carbon Cycle
Phosphorus, Iron, and Trace Mineral cycles
That creates a huge problem for origin of life scenarios. How did these cycle get "off the hook"? This is a gigantic interdependent system, which, if one part of the cycle is missing, nothing goes. 6
That's why the origin of glucose is a huge problem, and one of the unanswered questions in origin of life research.
The most important biogeochemical cycles are the carbon cycle, nitrogen cycle, oxygen cycle, phosphorus cycle, and the water cycle. The biogeochemical cycles always have a state of equilibrium. The state of equilibrium occurs when there is a balance in the cycling of the elements between compartments. Ecologists may also be interested in the sulfur cycle, the nutrient cycle, and the hydrogen cycle; however, ecologists are more interested in studying the carbon, nitrogen, oxygen, phosphorus, and water cycles. 3 Odum (1959) describes what are called more or less "perfect" cycles: biogeochemical cycles that involve equilibrium states. That is, there exists in nature a balance in the cycling of the element between various compartments, with the element or material moving into abiotic compartments about as fast as it moves into biotic compartments. Certain ecosystems may experience "shortages", but overall a balance exists on a global scale.
Terrestrial nitrogen–carbon cycle interactions at the global scale
2013 Jul 5
The productivity of plants and soil organisms strongly depends on nitrogen. This fact leads to a tight coupling of the terrestrial nitrogen and carbon cycles. Nitrogen availability plays an important role in controlling the productivity, structure and spatiotemporal dynamics of terrestrial ecosystems: perturbations in the nitrogen cycle will have repercussions in the carbon cycle, and vice versa. 2
The oxygen of Earth‟s atmosphere and oceans play a major role in the global biogeochemical nitrogen cycle.
BIOGEOCHEMICAL CYCLING OF MINERAL-FORMING ELEMENTS, page 25:
INTERDEPENDENCE OF BIOGEOCHEMICAL CYCLES
Since a large number of elements are essential for all, or at least some, of the components of the biosphere, it is obvious that the biogeochemical, cycles of these elements will be interdependent. Photosynthesis results in the evolution of 0xygen, and the incorporation of Carbon dioxide into the organic matter of living cells which, at the same time, incorporate nitrogen, sulfur, and phosphorus.Organic matter and O2 are used to drive independent cycles of sulfur, nitrogen, and carbon each of which requires the participation of phosphorus. The latter three cycles also regenerate carbon, sulfur, and nitrogen in the form required for the initial photosynthetic cell production. The five-element cycles are thus clearly interdependent and any change in one cycle will in the long term have a profound influence on the operation of the other four.
Electrons, life and the evolution of Earth's oxygen cycle
2008 May 16
Fundamentally, life on Earth comprises six major elements, namely H, C, N, O, S and P. The biogeochemical cycles of H, C, N, O, and S are coupled via biologically catalyzed electron transfer (redox) reactions. The early coevolution of the C, N and O cycles and the resulting non-equilibrium gaseous by-products can be used as a guide to search for the presence of life on terrestrial planets outside of our Solar System. These elements are the building blocks of all the major biological macromolecules including proteins, nucleic acids, lipids, and carbohydrates. The production of macromolecules requires an input of energy. The hallmark of biological energy transduction is non-equilibrium redox chemistry. Indeed, the evolution of life during the first half of Earth's history led to a network of electron transfer reactions that have driven fluxes of the first five of the ‘big six’ elements
Because all redox reactions are paired, the resulting network is a linked system of elemental cycles in which a forward reaction in one biogeochemical guild is complemented by a reverse reaction, usually, but not always, in another biogeochemical guild. The input of energy is almost exclusively derived from the Sun. For example, the reduction of inorganic carbon to organic molecules requires the addition of hydrogen and is endergonic. This reaction is catalyzed solely by chemoautotrophs and photoautotrophs, which use either the energy of preformed chemical bonds or light (the Sun) to drive the reduction reaction. The oxidation of organic molecules to inorganic carbon is catalyzed by heterotrophs, with the resulting liberation of energy. In some cases, the forward and reverse reactions can be catalyzed within the same biogeochemical guilds by altering either the mass balance or conditions of the reaction pathway. 1
The three main cycles of an ecosystem are the water cycle, the carbon cycle and the nitrogen cycle. These three cycles, working in balance, are responsible for carrying away waste materials and replenishing the ecosystem with the nutrients necessary to sustain life. If any of these three cycles should become unbalanced, the effects on the ecosystem can be catastrophic. 4
Chloroplasts and mitochondria: Completing an energy cycle
The finely tuned and regulated carbon cycle, essential for life
The nitrogen cycle, irreducible interdependence, and the origin of life
Sulfur and the Sulfur cycle, essential for life
Water, Phosphorus, Iron, and Trace Mineral cycles
Glucose and its importance for life
Where did Glucose come from in a prebiotic world ?
Feedbacks Between the Nitrogen, Carbon and Oxygen Cycles
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