Carbon cycle and water cycle, however are separate in their phases during cycle and their fates, nevertheless the both interact during the i) formation of carbonic acid when CO2 dissolves in the rainwater, ii) When CO2 dissolves in seawater to produce aqueous CO2 (CO2(aq)) it also forms carbonic acid (H2CO3) [CO2(aq) + H2O ↔ H2CO3]. The carbonic acid rapidly dissociates (splits apart) to produce bicarbonate ions (HCO3-) [H2CO3 ↔ HCO3- + H+]. In turn, bicarbonate ions can also dissociate into carbonate ions (CO32-) [HCO3- ↔ CO32- + H+]. The total dissolved inorganic carbon (DIC) in seawater is defined as the sum of [CO2(aq)] + [HCO3-] + [CO32-]. Typically, the surface waters of today's ocean have a pH of around 8.1, meaning that HCO3- is the dominant carbonate species, representing about 90% of DIC. The mineral calcium carbonate (CaCO3) is a fundamental building block for numerous marine organisms, from microscopic algae to reef-building corals. The formation or depletion of the CaCO3 is dependent upon the saturation of CO32- in seawater. Thus, with increase of atmospheric CO2 due to fossil fuel burning would result in saturation of seawater carbonate ions and bleaching of corals.

Dr Shekhar Mallick thank you for your contribution to the discussion

Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Humans have a huge effect on the carbon cycle when we burn wood, fossil fuels, and other forms of carbon. This action releases the stored carbon into the atmosphere, where it becomes a greenhouse gas. Greenhouse gases are gases in the atmosphere that absorb and release heat. When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air. Greenhouse gases trap heat in our atmosphere, causing global warming. When fossil fuels are burned, they release nitrogen oxides into the atmosphere, which contribute to the formation of smog and acid rain. Major sources of nitrogen oxide emissions include: Cars and trucks. Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, and also as a result of certain chemical reactions. The two cycles interact directly where carbon is transported dissolved or suspended in running water. Transport of weathering products and organic matter from the continents to the oceans is an important aspect of carbon cycling which is directly linked to water flux. In the food chain, plants move carbon from the atmosphere into the biosphere through photosynthesis. They use energy from the sun to chemically combine carbon dioxide with hydrogen and oxygen from water to create sugar molecules. Both carbon and water cycles are set in motion by energy from the sun. Sunlight plus water plus carbon dioxide are combined by photosynthesis in green plants to create carbohydrates. Sun energy causes evaporation of water from earth's surface into the atmosphere. Thus, the carbon dioxide released from the burning of fossil fuels is accumulating in the atmosphere, increasing average temperatures through the greenhouse effect, as well as dissolving in the ocean, causing ocean acidification.