BIO 105 Lecture Notes - Lecture 27: Nitrogen Cycle, Fish Kill, Denitrification
Document Summary
Forms the framework for organic molecules essential for all organisms. Co2 used in photosynthesis now carbon is an available form for consumers. Major transitions: oa ou (fossilication), ou ia (burning fossil fuels), oa ia (respiration/decomposition), ia oa (photosynthesis) Issues: climate change, deforestation; increase co2 in atmosphere. Important component for amino acids, proteins, nucleic acids (important component for life) Nitrogen fixation done by bacteria converts n2 to a usable form. Major transition: oa ia (denitrification, decomposition) exists most in atmosphere, ia oa (n-fixing bacteria) P is part of atp, nucleic acids (also important component of life) Major transition: oa ia (nutrient uptake), ia oa (decomposition, excretion), ia iu (sedimentation rocks), iu ia (weathering) Disturbance to natural cycles (n & p): fertilizers. Increased deposition of n, p in plants but also in water bodies due to runoff. Results in increased plant growth or algae growth (algal bloom) Death of fish (fishkill) due to low o2 availability.
