72 Ecology and Applied Environmental Science
The total phosphorous reservoir is found in the lithosphere and enters the
biosphere’s circulation through the rinsing of the ground surface (Figure 4.7).
Through water flow it reaches terrestrial and aquatic ecosystems and is
absorbed by plants and then goes through food chains. As in the other cycles,
various decomposers in the soil or water break down dead organic matter and
produce inorganic P, available to plants; P is utilized by producer organisms
in the form of soluble orthophosphates. Insoluble compound conversion to
orthophosphates is performed by specialized microorganisms. Dead organisms’ decomposition and their waste yield P to the environment in the form
of orthophosphates, which, however, can easily form insoluble compounds
with calcium and aluminium ions, which are quite common in the soil.
Recycling of P is almost complete in terrestrial ecosystems, where dead
able. The same occurs in fresh waters or shallow seas, where bound P deposition can easily return to food chains. Conversely, in the open ocean that
represents 85% of the marine surface, a continuous loss of P occurs due to
the accumulation of organic matter and mainly dead bodies, bones etc. in the
abysses and generally in great depths. Ocean upward currents enriching the
shallow water around ocean shelves with nutrients cannot restore the deep
deposits in P’s biogeochemical cycle. Thus, phosphoric compounds deposited
in the bottom of the ocean are retracted from the biosphere. Certainly their
recycling is still possible through tectonic upward movements of the sediments, but in a geological scale, i.e. in dozens or hundreds of million years.
Thus, the P cycle remains partly and for the short term open.
A significant part of P returns from the sea to the land through seabirds,
which consume fish and leave their waste on land. Nevertheless, these
movements of P are insufficient in compensating for the outflows from the
land to the sea.
ties of phosphoric substances excavated from the lithosphere’s natural deposits are transformed into phosphates by the fertilizer or detergent industries,
ending up in the hydrosphere and partly at the bottom of the oceans.
Phosphorus appears to be the limiting factor in more cases than any
other element. One reason is the easiness with which it creates insoluble
compounds; this fact inhibits its reception from plants and its transportation by surface and underground water. Another reason is P’s inability to
create gaseous compounds in the natural environment, which deprives it of
the ability to circulate in the atmosphere.
Urban fluid discharges contain significant P quantities, mainly due to
detergent usage, and the same is true for some industrial waste. The presence of P in liquid waste has become the reason for far gone eutrophication
states in lakes and coastal water, where it often is the limiting factor. The
potential contribution of phosphate fertilizers to eutrophication is smaller
due to the insoluble compounds that P creates with elements of the soil.
The total phosphorous reservoir is found in the lithosphere and enters the
biosphere’s circulation through the rinsing of the ground surface (Figure 4.7).
Through water flow it reaches terrestrial and aquatic ecosystems and is
absorbed by plants and then goes through food chains. As in the other cycles,
various decomposers in the soil or water break down dead organic matter and
produce inorganic P, available to plants; P is utilized by producer organisms
in the form of soluble orthophosphates. Insoluble compound conversion to
orthophosphates is performed by specialized microorganisms. Dead organisms’ decomposition and their waste yield P to the environment in the form
of orthophosphates, which, however, can easily form insoluble compounds
with calcium and aluminium ions, which are quite common in the soil.
Recycling of P is almost complete in terrestrial ecosystems, where dead
able. The same occurs in fresh waters or shallow seas, where bound P deposition can easily return to food chains. Conversely, in the open ocean that
represents 85% of the marine surface, a continuous loss of P occurs due to
the accumulation of organic matter and mainly dead bodies, bones etc. in the
abysses and generally in great depths. Ocean upward currents enriching the
shallow water around ocean shelves with nutrients cannot restore the deep
deposits in P’s biogeochemical cycle. Thus, phosphoric compounds deposited
in the bottom of the ocean are retracted from the biosphere. Certainly their
recycling is still possible through tectonic upward movements of the sediments, but in a geological scale, i.e. in dozens or hundreds of million years.
Thus, the P cycle remains partly and for the short term open.
A significant part of P returns from the sea to the land through seabirds,
which consume fish and leave their waste on land. Nevertheless, these
movements of P are insufficient in compensating for the outflows from the
land to the sea.
ties of phosphoric substances excavated from the lithosphere’s natural deposits are transformed into phosphates by the fertilizer or detergent industries,
ending up in the hydrosphere and partly at the bottom of the oceans.
Phosphorus appears to be the limiting factor in more cases than any
other element. One reason is the easiness with which it creates insoluble
compounds; this fact inhibits its reception from plants and its transportation by surface and underground water. Another reason is P’s inability to
create gaseous compounds in the natural environment, which deprives it of
the ability to circulate in the atmosphere.
Urban fluid discharges contain significant P quantities, mainly due to
detergent usage, and the same is true for some industrial waste. The presence of P in liquid waste has become the reason for far gone eutrophication
states in lakes and coastal water, where it often is the limiting factor. The
potential contribution of phosphate fertilizers to eutrophication is smaller
due to the insoluble compounds that P creates with elements of the soil.