Values, Alterations and Degradation of the Natural Landscape 103
Environmental threats are, as a rule, due to high concentrations of human
population and activities as well as to the fact that the coast is usually the
receptor of many environmental disturbances that have their source either
at the inland or at sea. The environmental pressures that come from intensive human activities cause a rapid degradation of both the terrestrial and
the marine part of coastal ecosystems. Basic factors of coasts’ degradation
are agricultural, industrial, residential and tourist activities, overfishing, as
well as the technical infrastructure works that disturb coastal ecosystems
to a great extent. Pollution and high pressures on the coastal and marine
environment in particular, degrade the natural ecosystems with further
multiple negative impacts on the trophic resources, health, the survival of
biological species, even on recreation and tourism; moreover, ignorance
about environmental parameters when designing coastal works or river
dams may cause, inter alia, coast erosion. The coastal zone receives pollution loads through direct waste disposal as well as indirectly by the rivers
and the atmosphere. It is estimated that more than 75% of marine pollution
comes from terrestrial sources. The coast’s condition is also influenced by
changes in salinity or the transport of debris and nutrients that are caused
by river dams, deforestation and other changes of land use. One more
threat is the probable rise of sea level as a result of the amplification of the
greenhouse effect.
5.4.3 the Mediterranean coastal Environment
Mediterranean coasts, in comparison to the Atlantic or the Pacific Ocean
coasts, present two main differences that are especially important for
their management. The first is the generally oligotrophic character of the
sea that washes them, and the second is the lack of noteworthy tide. The
oligotrophic character of the Mediterranean allows its characterization as
“ semi-desert” and is summarized in three elements:
• Small concentrations of nutrient salts (N, P, Si)
• Seasonal and limited development of phytoplankton and phytobenthic
populations
• Rare creation of anoxic or hypoxic conditions in the bottom and very
rarely in the water body
The oligotrophic character of the Mediterranean determines to a great
extent the effectiveness of man’s interventions in coastal problems, such
as urban wastewater management, the use of fertilizers in agriculture or
even the construction of river dams. The lack of significant tide intensifies
even more the oligotrophic character of the Mediterranean Sea, because
it deprives the marine environment of the everyday stirring of the bottom
caused by the tidal current. Moreover, it simplifies the technical parameters
Environmental threats are, as a rule, due to high concentrations of human
population and activities as well as to the fact that the coast is usually the
receptor of many environmental disturbances that have their source either
at the inland or at sea. The environmental pressures that come from intensive human activities cause a rapid degradation of both the terrestrial and
the marine part of coastal ecosystems. Basic factors of coasts’ degradation
are agricultural, industrial, residential and tourist activities, overfishing, as
well as the technical infrastructure works that disturb coastal ecosystems
to a great extent. Pollution and high pressures on the coastal and marine
environment in particular, degrade the natural ecosystems with further
multiple negative impacts on the trophic resources, health, the survival of
biological species, even on recreation and tourism; moreover, ignorance
about environmental parameters when designing coastal works or river
dams may cause, inter alia, coast erosion. The coastal zone receives pollution loads through direct waste disposal as well as indirectly by the rivers
and the atmosphere. It is estimated that more than 75% of marine pollution
comes from terrestrial sources. The coast’s condition is also influenced by
changes in salinity or the transport of debris and nutrients that are caused
by river dams, deforestation and other changes of land use. One more
threat is the probable rise of sea level as a result of the amplification of the
greenhouse effect.
5.4.3 the Mediterranean coastal Environment
Mediterranean coasts, in comparison to the Atlantic or the Pacific Ocean
coasts, present two main differences that are especially important for
their management. The first is the generally oligotrophic character of the
sea that washes them, and the second is the lack of noteworthy tide. The
oligotrophic character of the Mediterranean allows its characterization as
“ semi-desert” and is summarized in three elements:
• Small concentrations of nutrient salts (N, P, Si)
• Seasonal and limited development of phytoplankton and phytobenthic
populations
• Rare creation of anoxic or hypoxic conditions in the bottom and very
rarely in the water body
The oligotrophic character of the Mediterranean determines to a great
extent the effectiveness of man’s interventions in coastal problems, such
as urban wastewater management, the use of fertilizers in agriculture or
even the construction of river dams. The lack of significant tide intensifies
even more the oligotrophic character of the Mediterranean Sea, because
it deprives the marine environment of the everyday stirring of the bottom
caused by the tidal current. Moreover, it simplifies the technical parameters