Biogeochemical Flows Flashcards
Identify the four steps of the Nitrogen cycle, and list the three processes through which Nitrogen is “fixed” into a reactive form that can be used by organisms.
Nitrogen Fixation: atmospheric nitrogen (N2) is converted into ammonia (NH3) or other compounds that can be used by plants. It occurs through biological fixation (nitrogen-fixing bacteria), industrial fixation (Haber-Bosch process), and atmospheric fixation (lightning).
Nitrification: conversion of ammonia (NH3) into nitrite (NO2-) and then into nitrate (NO3-) by nitrifying bacteria. These forms of nitrogen can be taken up by plants.
Assimilation: Plants and animals take up nitrogen in the form of ammonia, nitrite, and nitrate to build their biological molecules, such as proteins and DNA.
Denitrification: This process completes the cycle by converting nitrates and nitrites back into atmospheric nitrogen (N2) or nitrous oxide (N2O) gas.
Explain why the Phosphorus cycle is the “slowest” of all the matter cycles.
The Phosphorus cycle is considered the “slowest” of all matter cycles because phosphorus has limited solubility in water and is primarily found in rocks and sediments. Phosphates are released very slowly through the weathering of rocks, making it less available for living organisms.
Give an example of how human activities can alter the Phosphorous and Nitrogen biogeochemical cycles.
The use of synthetic fertilizers in agriculture introduces excess phosphorous and nitrogen into the environment. Mining phosphorous for fertilizer production also increases the release of phosphorous. These activities can lead to eutrophication in water bodies and disrupt the natural cycles.
Describe at least three of the environmental effects of excess Nitrogen in the environment.
Excess Nitrogen in the environment leads to the nitrogen cascade, resulting in problems such as water pollution, eutrophication of water bodies (as previously mentioned), biodiversity loss, and health issues like nitrate contamination of drinking water, which can be harmful to humans and animals.
Define and explain the process of eutrophication.
Eutrophication is a process where excess nutrients, particularly nitrogen and phosphorous, enter water bodies, leading to increased plant growth (algae and aquatic plants). As these plants die and decompose, they deplete oxygen in the water, causing fish kills and disrupting the aquatic ecosystem.
List two control measures that can reduce the amount of P and N entering waterways, and one action that you can take to reduce your individual N footprint.
Control Measures: Control measures to reduce P and N entering waterways include implementing improved agricultural practices like reducing fertilizer application, using precision farming techniques, and controlling runoff. In urban areas, controlling sewage and wastewater discharges is crucial.
Individual Action: As an individual, you can reduce your Nitrogen footprint by conserving water, using fertilizers sparingly and responsibly, properly disposing of sewage and wastewater, and supporting sustainable agricultural practices.
