The Northern Atlantic Coasts
179
the Kristiansfjorden (Green et al. 1985) on the south coast as well as the
Gandsfjorden, Riskafjorden and Byfjorden in the Stavanger area (Bokn
and Molvrer 1988). In the report after the Chrysochromulina bloom
(Pedersen et al. 1989), clear effects of sewage discharges in deep water
(> 20 m) at a station in the outer area of Trysfjorden (Sfhgne, east of
Kristiansand) were mentioned, however, it was not reported in which
way the communities were influenced.
Iversen (1981) in his study tried to apply the use of a species pollution
index (cf. also Wallentinus 1979), by which he could identify affected sites
in the inner fjords, although he also found that the effects of wave exposure might influence the results. However, the amount of sewage being
discharged directly into these fjords at the time of the study in the late
1970s as well as the industrial discharges and land runoff certainly suggests a substantial impact on the macroalgal communities. In Bokn's study
(1979), where the inner fjord area had been receiving discharges from
among others an industry producing artificial fertilizers, the differences in
percentage composition of the main macroalgal groups were used to determine the impact. A similar approach has been suggested as part of the
future Norwegian monitoring programme for rocky substrates together
with parameters such as diversity and dominance indices, as well as ratios
between ephemeral and perennial organisms and depth distribution data
(Moy and Walday 1992).
6.5 The Norwegian West and North Coasts
Several macroalgae have their northern or southern distribution limits
along the Norwegian west coast, where in the northernmost part some
arctic species are common (e.g. Jaasund 1965; Lein and Kufner 1990;
Rueness et al. 1990). There are few published reports on the impact of
nutrient discharges on macro algal communities along the coastline north
of Bergen (cf. Fig. 6.1), whereas effects of fish wastes have been studied
in some areas (e.g. Gug et al. 1991 and references therein).
The nutrient enrichment effects in the early 1980s in the Glomfjord,
slightly north of the Arctic circle, were described by Molvrer and
Knutzen (1987). The fjord received discharges from an industry
producing ammonia and artificial fertilizers, while the freshwater inflow
was nearly constant due to water level regulation in a power plant. The
average annual discharges per day were calculated as 0.73 t of P and 5.2 t
of N, nearly all in inorganic form. The fjord is stratified into a slightly
brackish surface layer of around 1-2 m deep, an intermediate layer down
179
the Kristiansfjorden (Green et al. 1985) on the south coast as well as the
Gandsfjorden, Riskafjorden and Byfjorden in the Stavanger area (Bokn
and Molvrer 1988). In the report after the Chrysochromulina bloom
(Pedersen et al. 1989), clear effects of sewage discharges in deep water
(> 20 m) at a station in the outer area of Trysfjorden (Sfhgne, east of
Kristiansand) were mentioned, however, it was not reported in which
way the communities were influenced.
Iversen (1981) in his study tried to apply the use of a species pollution
index (cf. also Wallentinus 1979), by which he could identify affected sites
in the inner fjords, although he also found that the effects of wave exposure might influence the results. However, the amount of sewage being
discharged directly into these fjords at the time of the study in the late
1970s as well as the industrial discharges and land runoff certainly suggests a substantial impact on the macroalgal communities. In Bokn's study
(1979), where the inner fjord area had been receiving discharges from
among others an industry producing artificial fertilizers, the differences in
percentage composition of the main macroalgal groups were used to determine the impact. A similar approach has been suggested as part of the
future Norwegian monitoring programme for rocky substrates together
with parameters such as diversity and dominance indices, as well as ratios
between ephemeral and perennial organisms and depth distribution data
(Moy and Walday 1992).
6.5 The Norwegian West and North Coasts
Several macroalgae have their northern or southern distribution limits
along the Norwegian west coast, where in the northernmost part some
arctic species are common (e.g. Jaasund 1965; Lein and Kufner 1990;
Rueness et al. 1990). There are few published reports on the impact of
nutrient discharges on macro algal communities along the coastline north
of Bergen (cf. Fig. 6.1), whereas effects of fish wastes have been studied
in some areas (e.g. Gug et al. 1991 and references therein).
The nutrient enrichment effects in the early 1980s in the Glomfjord,
slightly north of the Arctic circle, were described by Molvrer and
Knutzen (1987). The fjord received discharges from an industry
producing ammonia and artificial fertilizers, while the freshwater inflow
was nearly constant due to water level regulation in a power plant. The
average annual discharges per day were calculated as 0.73 t of P and 5.2 t
of N, nearly all in inorganic form. The fjord is stratified into a slightly
brackish surface layer of around 1-2 m deep, an intermediate layer down