Biogeochemical Cycles Quiz

Overview of Biogeochemical Cycles

• Biogeochemical cycles involve the movement of chemical elements or molecules through biotic and abiotic compartments of an ecosystem, resulting in the recycling of elements.
• The law of conservation of matter states that matter cannot be created or destroyed, only recycled between organisms and the environment.
• Biogeochemical cycles are divided into gaseous cycles (carbon, oxygen, nitrogen, water) and sedimentary cycles (sulfur, phosphorus, rock).
• Carbon is important for life as it provides energy, regulates the Earth's temperature, and is a backbone of biomolecules.
• Plants pull carbon dioxide from the atmosphere through photosynthesis and store it as starch, which enters the food chain.
• Animals that eat plants incorporate carbon into their bodies and release it through respiration, excretion, and decomposition.
• Humans contribute to this cycling of matter by consuming plants and animals.
• Carbon is also stored in the ocean, where it is used by animals to form shells and other substances.
• Carbon sinks are anything that absorbs more carbon from the atmosphere than it releases.
• The nitrogen cycle involves the movement of nitrogen through the environment, including nitrogen fixation, nitrification, assimilation, and denitrification.
• Human alterations to the nitrogen cycle have doubled the rate of nitrogen input, increased greenhouse gas concentrations, caused soil nutrient losses, contributed to acidification, and increased nitrogen transfer through rivers to estuaries and coastal oceans.
• The sulfur cycle involves the movement of sulfur in the biosphere and geosphere, and is important for certain amino acids, fertilizers, batteries, and chemical production.
• The phosphorus cycle involves the deposition of phosphorus in oceans by rivers, its incorporation into marine sediments, and its uplift through weathering and volcanic eruption.