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 Biogeochemical cycles and nutrient movement 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/biology/ecology/biogeochemical-cycles/v/the-water-cycle 2024-05-06T19:22:43.24334365Z The water cycle The water cycle, powered by the sun, involves water moving in various forms between sources and sinks. It starts with evaporation from bodies of water, condensation into clouds, and precipitation back to the earth. This cycle also includes transpiration from plants and sublimation from ice to vapor. The majority of Earth's water is saltwater, with only a small percentage being freshwater in lakes, rivers, and groundwater. Sal Khan video https://cdn.kastatic.org/googleusercontent/okxRKXMHovcsPlENtDy06lBLXXn7tUYfX5eG7MOD5nZYSr_KyM9ufnRznemT6SbIP9tt1CNOA0D36g4_qHKE9eE The water cycle The water cycle, powered by the sun, involves water moving in various forms between sources and sinks. It starts with evaporation from bodies of water, condensation into clouds, and precipitation back to the earth. This cycle also includes transpiration from plants and sublimation from ice to vapor. The majority of Earth's water is saltwater, with only a small percentage being freshwater in lakes, rivers, and groundwater. https://cdn.kastatic.org/ka-youtube-converted/jFjI6y46QRk.mp4/jFjI6y46QRk.mp4 494 Biogeochemical cycles and nutrient movement https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/v/nitrogen-cycle 2024-05-06T19:22:43.24334365Z The nitrogen cycle The nitrogen cycle is a crucial process that converts atmospheric nitrogen into a form that plants and other organisms can use. This process, known as nitrogen fixation, is primarily carried out by bacteria. Nitrogen is essential for life, forming a key component in amino acids, ATP, and DNA. The cycle also includes the return of nitrogen to the atmosphere through decomposition. Sal Khan video https://cdn.kastatic.org/googleusercontent/gQTO9JBwADmey2m_RcYCR_nTXRtFSeKzD8OmiRJn46LlNov4Q7sqsF2imvMCMS8i7OccArqSUWSxktBugc1seihb0g The nitrogen cycle The nitrogen cycle is a crucial process that converts atmospheric nitrogen into a form that plants and other organisms can use. This process, known as nitrogen fixation, is primarily carried out by bacteria. Nitrogen is essential for life, forming a key component in amino acids, ATP, and DNA. The cycle also includes the return of nitrogen to the atmosphere through decomposition. https://cdn.kastatic.org/ka-youtube-converted/DsCMYyQ0NWU.mp4/DsCMYyQ0NWU.mp4 345 Biogeochemical cycles and nutrient movement https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/a/the-nitrogen-cycle 2024-05-29T17:16:29.06533157Z The nitrogen cycle The key role of microbes in nitrogen fixation. How overuse of nitrogen-containing fertilizers can cause algal blooms. article