Wetlands

What happens when more protons are pumped

increased ATP prod

what is the number of protons pumped depend on

# of steps an electron takes through the electron transport chain

What does the number of steps an electron takes depend on

the affinity of the final electron acceptor

What is the order to terminal electron acceptors organized by energy yield

O2

N

Mn

Fe

S

C

What is the efficiency of the system determined by

the frequency of oxidants being replenished and ratios of various oxidants in replenishing solution

What happens to oxidation potential with increased depth in saturated soils

decreases

Differences between seawater and river water

Seawater:

1. High pH

2. High ionic content

3. High SO4

4. Low nutrients and org. matter

River water

1. Low pH

2. Low ionic content

3. Low SO4

4. High nutrients and org. matter

What are the patterns of biogeochem. dependent on

the input/availability of materials for microbial reactions and amount of ene. released by reactions

What does sulfate in marine systems do

limits methane prod.

what do products of anaerobic respiration do

supports chemosynthesis

What happens to reduced products of anaerobic respiration

transported by diffusion or water flow to O2 rich areas--> oxidized by nitrifiers, sulfur bacteria + methanotrophs--> available for anaerobic respiration and methanogensis if O2 depletes again

Role of plants

stabilizes sediment

adds organic matter

adds O2 to deep sediments

allows gasses to escape/enter sediments

Aerenchyma

specialized tissue in stem that allows gas exchange and allows gasses to escape sediment

Methane in peatlands

Common

1. high acidity, low O2, cool temps, high C:N ratios

2. decreased oxidation potential and electron acceptors limited by high carbon env.

3. slow decomp and high N retention--> builds up org. matter

What happens to methane emissions with sulfate concentrations

Decreases

Reduced sulfur complexes metals

1. marine sediments are sinks for such metals

2. produces dimethyl sulfides--important for atmosphere

what do wetland do to nitrate

removes it in ground water and river water

impacts of wetlands

1. potential sources for: organic carbon, methane, methyl mercury, nitrous oxide, sulfides

2. potential sinks for: nutrients (N and P) and metal contaminants

Wetland

environment whose biogeochem. is influenced by saturated soils

Components:

1. saturation occurs seasonally/throughout year

2. plants usually extend above water line @ some point in year

3. anoxic conditions in soil bc O2 infiltration through H2O slower than air

Wooded Wetland

1. oxygenated roots--> problem for plants

2. pneumatophores: gas exchange

3. extra support bc shallow roots (buttresses)

Marshes

Herbaceous

seasonal and tidal

neutral pH

2 sources of water: salt and fresh

periodically inundated (tundra pond) and daily (tidal marsh)

Bogs

source of water from precip.

hydrophilic veg. (mosses/shrubs)

acidic--> represses bacterial decomp

Fens

water flowed through mineral soils

pH neutral to alkaline

forbs/grasses/shrubs

less acidic forms of bogs

Biogeochem. of wetlands

frequency of flooding influences processes that can occur

What happens to O2 during flooding

decreases

How does reoxygenation occur

through exposure to air

electron donor

reducing agent

electron acceptor

oxidizing agent

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