https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/v/biogeochemical-cycles 2024-05-06T19:22:43.24334365Z Biogeochemical cycles overview Biogeochemical cycles are nature's way of recycling essential elements for life, like water, carbon, nitrogen, and phosphorus. These cycles circulate these molecules through ecosystems and the entire biosphere. From the water cycle to the carbon cycle, these processes ensure the constant reuse of matter, while energy flows through the ecosystem. Sal Khan video https://cdn.kastatic.org/googleusercontent/RkZfK_GfyQENMLzn91OXdJD-6fcWtW4iD5D2jYN8t2sSGSm9SmuUbQpyotrMYkzgCLJGmJfw0BnooTWMjSSGNWw Biogeochemical cycles overview Biogeochemical cycles are nature's way of recycling essential elements for life, like water, carbon, nitrogen, and phosphorus. These cycles circulate these molecules through ecosystems and the entire biosphere. From the water cycle to the carbon cycle, these processes ensure the constant reuse of matter, while energy flows through the ecosystem. https://cdn.kastatic.org/ka-youtube-converted/ccWUDlKC3dE.mp4/ccWUDlKC3dE.mp4 475 The carbon cycle https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/a/introduction-to-biogeochemical-cycles 2025-06-30T13:17:39.587845569Z Intro to biogeochemical cycles Get an overview of how atoms are recycled through Earth's ecosystems via biogeochemical cycles. article https://www.khanacademy.org/science/bmc-grade-9-science/x345505a97fc4a662:energy-flow-in-an-ecosystem/x345505a97fc4a662:bio-geo-chemical-cycle/a/hs-biogeochemical-cycles-review 2021-04-29T08:02:39Z Biogeochemical cycles review article https://www.khanacademy.org/science/how-we-interact-with-our-environment/x049400914d70a1b7:ecosystem/x049400914d70a1b7:nutrient-cycling/e/hs-biogeochemical-cycles 2026-04-08T00:16:02.937952483Z Biogeochemical cycles Test your knowledge of the water cycle, carbon cycle, and nitrogen cycle! Ashley exercise https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/v/carbon-cycle 2024-05-06T19:22:43.24334365Z The carbon cycle Carbon is crucial for life, forming molecules like glucose, ATP, amino acids, and DNA. The carbon cycle involves plants taking in carbon dioxide, fixing carbon, and creating organic molecules. Animals eat plants, metabolize the molecules, and release carbon dioxide. This cycle keeps carbon circulating in the biosphere. Sal Khan video https://cdn.kastatic.org/googleusercontent/PANHGUsQ7xlmTUmBIQ5gOGmQph_QMC3IukyvEWtMqz7ynXac-nf0w-2gbg0-Lsah0_bhu8pJPMKf_GMxQJUfwO3B The carbon cycle Carbon is crucial for life, forming molecules like glucose, ATP, amino acids, and DNA. The carbon cycle involves plants taking in carbon dioxide, fixing carbon, and creating organic molecules. Animals eat plants, metabolize the molecules, and release carbon dioxide. This cycle keeps carbon circulating in the biosphere. https://cdn.kastatic.org/ka-youtube-converted/_dYkByQ9Kmg.mp4/_dYkByQ9Kmg.mp4 517 The carbon cycle https://www.khanacademy.org/science/bmc-grade-9-science/x345505a97fc4a662:energy-flow-in-an-ecosystem/x345505a97fc4a662:bio-geo-chemical-cycle/v/the-carbon-cycle 2025-07-01T18:08:15.179962416Z The carbon cycle Carbon moves through the environment in a continuous cycle, shifting between reservoirs such as plants, animals, soil, air, water, and rocks. Key processes—photosynthesis, respiration, decomposition, and combustion—drive this movement. While the biological carbon cycle happens quickly, the geological carbon cycle takes millions of years. Human actions can disrupt this cycle, contributing to climate change. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/45df2542-dadf-4897-977d-715d87892a21_1280_720_base.png The carbon cycle Carbon moves through the environment in a continuous cycle, shifting between reservoirs such as plants, animals, soil, air, water, and rocks. Key processes—photosynthesis, respiration, decomposition, and combustion—drive this movement. While the biological carbon cycle happens quickly, the geological carbon cycle takes millions of years. Human actions can disrupt this cycle, contributing to climate change. https://cdn.kastatic.org/ka-youtube-converted/XynPVsE1fd4.mp4/XynPVsE1fd4.mp4 284 The carbon cycle https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/a/the-carbon-cycle 2025-05-22T20:38:55.753848076Z The carbon cycle Learn how carbon moves through Earth's ecosystems and how human activities are altering the carbon cycle. article https://www.khanacademy.org/science/ap-college-environmental-science/x0b0e430a38ebd23f:the-living-world-ecosystems-and-biodiversity/x0b0e430a38ebd23f:biogeochemical-cycles/a/the-carbon-cycle-article 2022-09-07T01:03:50.067296221Z The carbon cycle Review your understanding of the carbon cycle with this free article aligned to NGSS and AP standards. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:energy-and-matter-in-biological-systems/x230b3ff252126bb6:biogeochemical-cycles/a/carbon-cycle 2024-05-09T17:42:08.599818576Z The carbon cycle Learn about the carbon cycle and how carbon moves between the biosphere and the geosphere. article https://www.khanacademy.org/science/bmc-grade-9-science/x345505a97fc4a662:energy-flow-in-an-ecosystem/x345505a97fc4a662:bio-geo-chemical-cycle/e/understand-the-carbon-cycle 2025-07-13T07:33:51.252224157Z Understand: the carbon cycle Check your understanding of the carbon cycle in this set of free practice questions aligned to NGSS standards. exercise https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:energy-and-matter-in-biological-systems/x230b3ff252126bb6:biogeochemical-cycles/e/apply-the-carbon-cycle 2025-06-13T16:17:46.628796572Z Apply: the carbon cycle Apply your understanding about the carbon cycle in this set of free, standards-aligned practice questions. Wieteke Holthuijzen exercise