Page 236 - Materials Chemistry, Second Edition

222 R.K. Rosenbaum et al.

Terrestrial eutrophication Aquatic eutrophication
Waterborne emissions
Airborne emissions of Waterborne emissions of dissolved organic
N-compounds of N and P compounds compounds (DOC,
COD, BOD)

Transport/removal of N
Atmospheric fate and and P in water Transport/removal in
transport water compartments
compartments

Deposition Deposition
on land on water

Increased nutrient
Increased concentration in
leaching to aquatic compartments
groundwater (P in freshwater, N in
marine)

Increased/criti- Increased/criti-
cal exposure of cal exposure of Increased alga
terrestrial aquatic growth
ecosystems ecosystems

Oxygen depletion
Changes in
Chronic effects in bottom strata of
on vegetation species lakes and coastal
composition
waters

Damage to Damage to Damage to
Damage to Damage to terrestrial freshwater marine Damage to
forestry crops fishing
ecosystems ecosystems ecosystems
Fig. 10.14 Impact pathways for terrestrial and aquatic (freshwater and marine) eutrophication
[adapted from EC-JRC (2011)]

• Oxygen is steadily depleted in bottom layers, which leads to suffocation of
bottom-dwelling species and fish
• This is additionally accelerated by the oxygen consuming decomposition of the
dead species and sedimented dead algae
• The aquatic medium becomes hypoxic and finally anoxic, favouring the for-
mation of reducing compounds and noxious gases (mercaptans, methane)