An increasing global demand for biomass may be met by an increased production of macroalgae at sea. Macroalgae are, among other applications, a sufficient diet resource for humans and animals. The red alga Palmaria palmata and the brown alga Saccharina latissima have previously been cultivated in European waters, and potential large scale cultivation of these algae are relevant, because both algal species are commercially demanded and are relatively easy to handle. The present study investigated suitable cultivation areas in Danish waters for these two algal species in regard to a variation in the abiotic conditions: light, temperature, and salinity. Published tolerance levels for P. palmata and S. latissima in relation to light, temperature, and salinity were reviewed and compared to registered levels of the abiotic factors at five sites in Denmark. An in situ experiment was conducted at the same five sites to test the theoretical findings in practise. The analysis of the abiotic conditions showed, that light conditions are sufficient to meet the light saturation level of both algal species from noon to 1pm in all months during the year. It was also found that the large seasonal variation and a site specific variation in light attenuation determine optimal cultivation depth. Water temperatures were found to exceed the tolerance level for P. palmata in July, August, and September and for S. latissima in August at some sites. A large geographical variation in salinity were seen between sites, with registrations of salinities below the tolerance level of the algae at the sites Agersø, Bisserup, and Fåborg, and even near Fredericia for P. palmata. The results of the in situ experiment showed an increased biomass over a seven months cultivation period for P. palmata and S. latissima at the Limfjord (28±3 PSU) and near Fredericia (21±3 PSU). Cultivation near Agersø (17±5 PSU) was not suitable due to negative growth. At the sites Bisserup and Fåborg all lines were lost. Cultivation of P. palmata near Fredericia provided the highest specific growth rate of 0.038 d-1 which was significant from the other sites. This growth rate was comparable with other published results (0.013-0.14 d-1 ). Cultivation of S. latissima provided very low specific growth rates (-0.002- 0.006 d-1 ), and no significance was seen between sites. Other Danish and international studies proved clearly higher growth rates (0.023-0.095 d-1 ), therefore, this proposed cultivation method is unsuitable for this alga.
|Uddannelser||Miljøbiologi, (Bachelor/kandidatuddannelse) Kandidat|
|Udgivelsesdato||21 mar. 2014|
|Vejledere||Morten Foldager Pedersen|
- cultivation depth