98 Ecology and Applied Environmental Science
5.3 aquatic EnvironMEnt
5.3.1 Marine Ecosystems
The continuous interaction of water masses with each other and with the sea
bottom leads marine organisms to close relationships with the total of the
marine environment (trophic, reproductive, nesting dependence); therefore, it is
not an exaggeration to consider the whole marine space as a unified ecosystem.
For practical reasons, it is advisable to distinguish at least two great compartments in the marine environment: the sea bottom’s ecosystem and the
ecosystem of the water body. The presence or absence of light constitutes a
decisive criterion for the distinction of partial compartments, because this
is what controls photosynthesis. Primary production either by phytoplankton or by phytobenthos constitutes the energy basis of every marine trophic
web; it also supplies with food the great depths where complete darkness
prevails. Another important criterion for the compartmentalization of the
marine ecosystem is the distance from the coast. Land’s influence on the
marine environment is often important; it distinguishes the coastal marine
ecosystem from the ecosystem of the open sea.
The ecosystems of the sea bottom can be divided into (a) the ecosystems
of the continental shelf, that begin from the coastline and reach the beginning of the continental rise, in a depth of about 150–180 meters and (b) the
ecosystems of the great depths that begin from the continental rise and continue down to the abyss plains and hadal trenches (maximum depth almost
11,000 meters). Correspondingly, the ecosystems of the water body can be
divided into (a) the ecosystems of neritic (coastal) waters, found above the
continental shelf and (b) the pelagic ecosystems, found far away from the
coasts, beyond the continental shelf.
5.3.1.1 Ocean
The ocean is the oldest, largest and more stable ecosystem of the planet. Its
function is determinately influenced by natural factors, such as surge, tide, currents, salinity, temperature, pressure and intensity of radiation. Trophic chains
begin with the smaller known producer organisms and end with the biggest
animals of the planet. In great depths, near geothermal springs, isolated ecosystems develop with unique characteristics in which primary production
is not based on photosynthetic organisms but on chemosynthetic bacteria.
5.3.1.2 Estuary
Coastal marine systems are generally much more productive than those of
the open sea, because they are much less limited by light and nutrients. The
most characteristic examples are coral reefs, coastal wetlands and estuaries.
5.3 aquatic EnvironMEnt
5.3.1 Marine Ecosystems
The continuous interaction of water masses with each other and with the sea
bottom leads marine organisms to close relationships with the total of the
marine environment (trophic, reproductive, nesting dependence); therefore, it is
not an exaggeration to consider the whole marine space as a unified ecosystem.
For practical reasons, it is advisable to distinguish at least two great compartments in the marine environment: the sea bottom’s ecosystem and the
ecosystem of the water body. The presence or absence of light constitutes a
decisive criterion for the distinction of partial compartments, because this
is what controls photosynthesis. Primary production either by phytoplankton or by phytobenthos constitutes the energy basis of every marine trophic
web; it also supplies with food the great depths where complete darkness
prevails. Another important criterion for the compartmentalization of the
marine ecosystem is the distance from the coast. Land’s influence on the
marine environment is often important; it distinguishes the coastal marine
ecosystem from the ecosystem of the open sea.
The ecosystems of the sea bottom can be divided into (a) the ecosystems
of the continental shelf, that begin from the coastline and reach the beginning of the continental rise, in a depth of about 150–180 meters and (b) the
ecosystems of the great depths that begin from the continental rise and continue down to the abyss plains and hadal trenches (maximum depth almost
11,000 meters). Correspondingly, the ecosystems of the water body can be
divided into (a) the ecosystems of neritic (coastal) waters, found above the
continental shelf and (b) the pelagic ecosystems, found far away from the
coasts, beyond the continental shelf.
5.3.1.1 Ocean
The ocean is the oldest, largest and more stable ecosystem of the planet. Its
function is determinately influenced by natural factors, such as surge, tide, currents, salinity, temperature, pressure and intensity of radiation. Trophic chains
begin with the smaller known producer organisms and end with the biggest
animals of the planet. In great depths, near geothermal springs, isolated ecosystems develop with unique characteristics in which primary production
is not based on photosynthetic organisms but on chemosynthetic bacteria.
5.3.1.2 Estuary
Coastal marine systems are generally much more productive than those of
the open sea, because they are much less limited by light and nutrients. The
most characteristic examples are coral reefs, coastal wetlands and estuaries.