2
W. Schramm and P.R. Nienhuis
In contrast, hypertrophication, also termed "nutrient pollution", means
over-enrichment or excess supply of nutrients beyond the maximum
critical self-regulatory level to an extent that detrimental processes cause
irreversible changes in the aquatic communities, as long as nutrient
loadings are not reduced.
The direct and indirect effects of landborne, seaborne and atmospheric
pollution on coastal ecosystems have been documented in an ever growing
number of observations on structural and functional changes leading to a
general deterioration of the coastal environment. Ecological responses to
pollution, either correlative or causal, comprise many examples such as
enhanced plankton production, resulting in increased sedimentation and
benthic production. In turn, this may lead to oxygen depletion events and
die-back of the benthic system, and diseases and mass mortality among
pelagic and benthic organisms.
Several of the most conspicuous effects which probably can be related to
both pollution in general and to eutrophication and hypertrophication in
particular, are the changes in the marine benthic vegetation, composed of
micro algae, macrolgae (seaweeds) and seagrasses. Specific changes and
secondary effects are typically conneted with increasing eutrophication:
1. Increasing nutrient levels.
2. Occurrence of phytoplankton blooms.
3. Decline or disappearance of certain perennial plant communities, often
replaced by annual, fast growing forms (e.g. folious green algae or
filamentous algae).
4. Reduced diversity of the flora and associated fauna.
5. Mass development (blooms) of short-lived annual forms which may
become "nuisance algae", owing to the fact that they hinder fishing
activities and navigation, or pollute amenity beaches when cast ashore.
6. Changing depth distribution of benthic algae owing to the reduced light
transmittance through the water column.
As a result of these changes, secondary effects can be noted:
1. Increased plant biomass production necessarily leads to enrichment of
the pool of particulate and dissolved organic material both in seawater
and sediments.
2. Increasing numbers of benthic filter-feeders and detritus-feeders.
3. Enhancement of heterotrophic oxygen-consuming processes which lead
to oxygen depletion and finally hydrogen sulphide development.
4. Mass mortalities of plants and animals, in particular in the benthic
system.
S. Decline in zooplankton diversity and fish species.
W. Schramm and P.R. Nienhuis
In contrast, hypertrophication, also termed "nutrient pollution", means
over-enrichment or excess supply of nutrients beyond the maximum
critical self-regulatory level to an extent that detrimental processes cause
irreversible changes in the aquatic communities, as long as nutrient
loadings are not reduced.
The direct and indirect effects of landborne, seaborne and atmospheric
pollution on coastal ecosystems have been documented in an ever growing
number of observations on structural and functional changes leading to a
general deterioration of the coastal environment. Ecological responses to
pollution, either correlative or causal, comprise many examples such as
enhanced plankton production, resulting in increased sedimentation and
benthic production. In turn, this may lead to oxygen depletion events and
die-back of the benthic system, and diseases and mass mortality among
pelagic and benthic organisms.
Several of the most conspicuous effects which probably can be related to
both pollution in general and to eutrophication and hypertrophication in
particular, are the changes in the marine benthic vegetation, composed of
micro algae, macrolgae (seaweeds) and seagrasses. Specific changes and
secondary effects are typically conneted with increasing eutrophication:
1. Increasing nutrient levels.
2. Occurrence of phytoplankton blooms.
3. Decline or disappearance of certain perennial plant communities, often
replaced by annual, fast growing forms (e.g. folious green algae or
filamentous algae).
4. Reduced diversity of the flora and associated fauna.
5. Mass development (blooms) of short-lived annual forms which may
become "nuisance algae", owing to the fact that they hinder fishing
activities and navigation, or pollute amenity beaches when cast ashore.
6. Changing depth distribution of benthic algae owing to the reduced light
transmittance through the water column.
As a result of these changes, secondary effects can be noted:
1. Increased plant biomass production necessarily leads to enrichment of
the pool of particulate and dissolved organic material both in seawater
and sediments.
2. Increasing numbers of benthic filter-feeders and detritus-feeders.
3. Enhancement of heterotrophic oxygen-consuming processes which lead
to oxygen depletion and finally hydrogen sulphide development.
4. Mass mortalities of plants and animals, in particular in the benthic
system.
S. Decline in zooplankton diversity and fish species.