70
M. Puch . J. Larsen
trients, or to oxygen consumption to an extent which creates negative ecological effects
or leads to significantly increased concentrations of heavy metals or hazardous substances in animals and plants.
In order to monitor water quality, Secchi depth, nutrients, temperature, salinity, oxygen content and fluorescence are measured at each of the four stations in the programme
(Fig. 7.2). The results of the weekly measurements are reported to the authorities within
a week of the samples being taken. The results are supplemented by measurements
carried out by regional and national Danish and Swedish authorities.
7.2.2
Monitoring of Benthic Vegetation and Benthic Fauna
It is generally accepted that there will be a temporary reduction in species composition,
distribution and biomass of flora and fauna of up to 25% in the outer impact area, while
permanent effects within the inner impact area of the alignment can be accepted.
7.2.2.1
Benthic Vegetation
The vegetation programme includes monitoring and control of the occurrence of pondweed (Ruppia sp.), eelgrass (Zostera marina) and sweet tangle (Laminaria saccharina).
The programmes for pondweed and eelgrass are carried out once a year in August/
September and include aerial photography and subsequent digital image processing of
the distribution of the vegetation along the coast out to the 6-m-depth contour line
(lower distribution limit for eelgrass in the 0resund) in the area from Aflandshage to
Vedbrek, the coast of Saltholm, and the Swedish coast from Falsterbo to Landskrona. In
addition to this analyses are made of the vegetation coverage and biomass of eelgrass
and pondweed along transects within the outer impact area as well as the control area
(Fig. 7.3 and 7.4). For eelgrass also the shoot density is measured. The monitoring of
sweet tangle takes place at six localities in August/September using photography and
surveying.
7.2.2.2
Benthic Fauna
The programme for benthic fauna includes monitoring of the shallow water fauna «6 m
depth) and deep-water fauna (>6 m depth), together with a separate programme for
common mussel. Shallow-water fauna is collected at a small number of transects and
stations during the spring, while a more extended sampling takes place in the autumn.
The samples are analysed for the occurrence of species, number and biomass (Fig. 7.5).
Samples of deep-water fauna are collected annually in April/May at 17 stations with
a view to determine biomass, number and size distribution. Common mussels are sampled annually in October/November at 48 stations. Coverage is assessed and biomass,
number and size distribution determined (Fig. 7.6). The content of heavy metals in
mussels at ten stations is also determined.
M. Puch . J. Larsen
trients, or to oxygen consumption to an extent which creates negative ecological effects
or leads to significantly increased concentrations of heavy metals or hazardous substances in animals and plants.
In order to monitor water quality, Secchi depth, nutrients, temperature, salinity, oxygen content and fluorescence are measured at each of the four stations in the programme
(Fig. 7.2). The results of the weekly measurements are reported to the authorities within
a week of the samples being taken. The results are supplemented by measurements
carried out by regional and national Danish and Swedish authorities.
7.2.2
Monitoring of Benthic Vegetation and Benthic Fauna
It is generally accepted that there will be a temporary reduction in species composition,
distribution and biomass of flora and fauna of up to 25% in the outer impact area, while
permanent effects within the inner impact area of the alignment can be accepted.
7.2.2.1
Benthic Vegetation
The vegetation programme includes monitoring and control of the occurrence of pondweed (Ruppia sp.), eelgrass (Zostera marina) and sweet tangle (Laminaria saccharina).
The programmes for pondweed and eelgrass are carried out once a year in August/
September and include aerial photography and subsequent digital image processing of
the distribution of the vegetation along the coast out to the 6-m-depth contour line
(lower distribution limit for eelgrass in the 0resund) in the area from Aflandshage to
Vedbrek, the coast of Saltholm, and the Swedish coast from Falsterbo to Landskrona. In
addition to this analyses are made of the vegetation coverage and biomass of eelgrass
and pondweed along transects within the outer impact area as well as the control area
(Fig. 7.3 and 7.4). For eelgrass also the shoot density is measured. The monitoring of
sweet tangle takes place at six localities in August/September using photography and
surveying.
7.2.2.2
Benthic Fauna
The programme for benthic fauna includes monitoring of the shallow water fauna «6 m
depth) and deep-water fauna (>6 m depth), together with a separate programme for
common mussel. Shallow-water fauna is collected at a small number of transects and
stations during the spring, while a more extended sampling takes place in the autumn.
The samples are analysed for the occurrence of species, number and biomass (Fig. 7.5).
Samples of deep-water fauna are collected annually in April/May at 17 stations with
a view to determine biomass, number and size distribution. Common mussels are sampled annually in October/November at 48 stations. Coverage is assessed and biomass,
number and size distribution determined (Fig. 7.6). The content of heavy metals in
mussels at ten stations is also determined.