6 The Northern Atlantic Coasts
(The Swedish West Coast, Norway and Iceland)
1. W ALLENTINUS
6.1 Introduction
The macro algal communities are highly significant elements in rocky
shore areas, especially on coasts with many bays or archipelagos such as
the Swedish Skagerrak coast and the Norwegian fjords.
Shift in the composition of these communities caused by eutrophication is especially important for the marine ecosystem, since several functions are altered:
1. The fixing of solar energy and nutrients, which is changed from
going into the comparatively large biomasses of mainly long-lived
perennial seaweeds, to being mainly bound to ephemeral algae.
The latter fluctuate considerably over the year and thus by their
breakdown give pulsed releases of both carbon and nutrients back
to the marine ecosystem, which causes reduced stability of the
system.
2. The loss of an architecturally important structure comprised especially of the large perennials (mainly brown algae). Instead the
communities become totally dominated by smaller species
(filamentous and sheet-like algae), reducing the system from a
three-dimensional to a more or less two-dimensional structure.
This in turn has a high impact on macrofauna and fish in the
community and also affects commercially important species, which
use the large plants for foraging and shelter. However, the filamentous algae are of great importance for the micro- and meiofauna as
well as for smaller macrofaunal species, since they provide a huge
increase in the available surface area.
Dept. of Marine Botany and Goteborg Marine Research Centre, University of Goteborg,
Carl Skottsbergs gata 22,41319 Goteborg, Sweden
Ecological Studies, Vol. 123
SchrammlNienhuis (eds) Marine Benthic Vegetation
© Springer-Verlag Berlin Heidelberg 1996
(The Swedish West Coast, Norway and Iceland)
1. W ALLENTINUS
6.1 Introduction
The macro algal communities are highly significant elements in rocky
shore areas, especially on coasts with many bays or archipelagos such as
the Swedish Skagerrak coast and the Norwegian fjords.
Shift in the composition of these communities caused by eutrophication is especially important for the marine ecosystem, since several functions are altered:
1. The fixing of solar energy and nutrients, which is changed from
going into the comparatively large biomasses of mainly long-lived
perennial seaweeds, to being mainly bound to ephemeral algae.
The latter fluctuate considerably over the year and thus by their
breakdown give pulsed releases of both carbon and nutrients back
to the marine ecosystem, which causes reduced stability of the
system.
2. The loss of an architecturally important structure comprised especially of the large perennials (mainly brown algae). Instead the
communities become totally dominated by smaller species
(filamentous and sheet-like algae), reducing the system from a
three-dimensional to a more or less two-dimensional structure.
This in turn has a high impact on macrofauna and fish in the
community and also affects commercially important species, which
use the large plants for foraging and shelter. However, the filamentous algae are of great importance for the micro- and meiofauna as
well as for smaller macrofaunal species, since they provide a huge
increase in the available surface area.
Dept. of Marine Botany and Goteborg Marine Research Centre, University of Goteborg,
Carl Skottsbergs gata 22,41319 Goteborg, Sweden
Ecological Studies, Vol. 123
SchrammlNienhuis (eds) Marine Benthic Vegetation
© Springer-Verlag Berlin Heidelberg 1996