Introduction
w. SCHRAMM! and P.H. NIENHUlS 2
There is a tendency towards an increasing burden to marine coastal systems
as a direct result of growing human activities, which had already started at
the end of the last century, but became especially manifest during the past
three to four decades. Increasing amounts of various types of wastes and
pollutants including nutrients enter the coastal waters via rivers, direct
discharges from land drainage systems, diffuse land runoff, dumping and
via the atmosphere. These wastes and pollutants are derived from industry,
urbanization, traffic, agriculture and mariculture together with other forms
of intensified use of land and sea.
As a result, in many shallow coastal areas which are the primary
recipients of land runoff, a trend towards increasing levels of pollutants and
nutrients has been observed. Particularly in enclosed or semi-enclosed
water bodies such as estuaries, bays, harbours or fjords, the discharge of
nutrient-carrying wastes has led to eutrophication and in extreme cases to
hypertrophication.
Eutrophication is defined here as the process of natural or man-made
enrichment with inorganic nutrient elements, mainly nitrogen and phosphorus, beyond the maximum critical level of the self-regulatory capacity of
a given system for a balanced flow and cycling of nutrients. The critical
levels may of course vary considerably between oligotrophic and eutrophic
systems. Eutrophication may induce changes in the structure and in the
flow of energy and matter through a system, although such changes are not
necessarily harmful to the system. In fact, increased supply of nutrients per
se into the sea, where nutrients are often limiting primary production, has
generally been considered as beneficial in enhancing pelagic and benthic
productivity and thus improving the harvest by man from the sea.
1 Institut fUr Meereskunde, Universitat Kiel, Diisternbrooker Weg 20, 24105 Kiel, Germany
2 Netherlands Institute of Ecology, Centre for Limnology, Rijksstraatweg 6, 3631 AC
Nieuwersluis, The Netherlands
Ecological Studies, Vol. 123
Schramm/Nienhuis (eds) Marine Benthic Vegetation
© Springer-Verlag Berlin Heidelberg 1996
w. SCHRAMM! and P.H. NIENHUlS 2
There is a tendency towards an increasing burden to marine coastal systems
as a direct result of growing human activities, which had already started at
the end of the last century, but became especially manifest during the past
three to four decades. Increasing amounts of various types of wastes and
pollutants including nutrients enter the coastal waters via rivers, direct
discharges from land drainage systems, diffuse land runoff, dumping and
via the atmosphere. These wastes and pollutants are derived from industry,
urbanization, traffic, agriculture and mariculture together with other forms
of intensified use of land and sea.
As a result, in many shallow coastal areas which are the primary
recipients of land runoff, a trend towards increasing levels of pollutants and
nutrients has been observed. Particularly in enclosed or semi-enclosed
water bodies such as estuaries, bays, harbours or fjords, the discharge of
nutrient-carrying wastes has led to eutrophication and in extreme cases to
hypertrophication.
Eutrophication is defined here as the process of natural or man-made
enrichment with inorganic nutrient elements, mainly nitrogen and phosphorus, beyond the maximum critical level of the self-regulatory capacity of
a given system for a balanced flow and cycling of nutrients. The critical
levels may of course vary considerably between oligotrophic and eutrophic
systems. Eutrophication may induce changes in the structure and in the
flow of energy and matter through a system, although such changes are not
necessarily harmful to the system. In fact, increased supply of nutrients per
se into the sea, where nutrients are often limiting primary production, has
generally been considered as beneficial in enhancing pelagic and benthic
productivity and thus improving the harvest by man from the sea.
1 Institut fUr Meereskunde, Universitat Kiel, Diisternbrooker Weg 20, 24105 Kiel, Germany
2 Netherlands Institute of Ecology, Centre for Limnology, Rijksstraatweg 6, 3631 AC
Nieuwersluis, The Netherlands
Ecological Studies, Vol. 123
Schramm/Nienhuis (eds) Marine Benthic Vegetation
© Springer-Verlag Berlin Heidelberg 1996