OCS 3103 Exam 3

wetlands, nitrogen cycle, phosphorus cycle

electron donor

agent that is oxidized

electron acceptor

agent that is reduced

oxidation

oxidation number increases

reduction

oxidation number decreases

marsh

herbaceous plants, surface flow dominated

swamp

woody plants, surface flow and groundwater dominated

bog

mosses, acidic/ oligotrophic soil, precipitation dominated

fen

grasses and sedges, neutral-alkaline soil, groundwater dominated

N2, 0

dinitrogen gas formula & ox. #

NO3-, +5

nitrate formula & ox. #

NO2-, +3

nitrite formula & ox #

NH4+, -3

ammonium formula & ox #

NH3, -3

ammonia formula & ox #

nitrogen fixation

N2 —> NH3

nitrification

NH3 —> NO3-

assimilation

NH3 —> organic N

ammonification

organic N —> NH3

denitrification

NO3- —> N2

anammox

NH3 + NO2- —> N2

nitrogen fixation, denitrification

reactions where nitrogen is reduced

nitrification, anammox

reactions where nitrogen is oxidized

uplift, weathering, transport, sediment burial

four components of the global phosphorus cycle

microbial respiration

source of nitrogen availability

weathering of sedimentary rock

source of phosphorus availability

oxygen, nitrate, iron, manganese, sulfate, methanogenesis

electron accepting pathways (reduction) in soil microbial communities

no atmospheric P component, N is more enriched

differences between nitrogen and phosphorus cycles