ENVS 1500 Lecture Notes - Lecture 12: Nitrogen Cycle
27 Aug 2015
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Document Summary
Envs 1500 winter lecture #1 nutrient cycling. Nutrient cycling is the transformation and movement and re use of metabolically essential elements such as carbon, nitrogen, phosphorus, iron, potassium, calcium and many others. Crustaceans cannot grow in lakes with very low calcium, low ca levels in northern lakes in on and que have prevented colonization of these lakes by zebra mussels which are confined to the southern lakes. Low p and n levels affect ecosystem productivity and therefore biomass. P is used in nucleotides (dna, rna, atp) Sidebar: low p inputs freshwater productivity, however excessive p use in agricultural fertilizers is a major source of degraded water quality. Phosphorus consumption is up, we will most likely run out unless we find another source of it. Nitrogen used in amino acids which are protein building blocks. Only natural source of biologically available n in ecosystems in bacterial fixation: conversion of gaseous n2 into usable ammonia nh3.
