Carbon dioxide (CO2) emissions contribute to an increased mean temperature of the Earth and ocean acidification. The environmental changes give great concern for biodiversity and future environmental sustainability. Microalgae can possibly be used to recycle CO2 emissions and the biomass could be used for production of high value products like, healthy human food or biofuels. The aim of this study was to examine the effect of carbon dioxide on algae biomass production and species composition of a natural spring bloom community (NC) from the Baltic Sea. Spring blooms are dominated by diatoms which could be a good candidate for CO2 assimilation. The NC was exposed to CO2 gas and compared with NC without added CO2 sources (Air control). The NC was cultivated under controlled laboratory conditions with daily sampling for chlorophyll a and pH measurement. Species composition was investigated by microscope. Low pH reduced CO2 assimilation of the NC but was compensated for since no effect of CO2 could be seen on biomass production. Additionally CO2 had no effect on species composition indicating the species in the NC to be resistant to pH fluctuations. A clear shift in species composition could be seen over time. The diatoms dominated at experiment end confirming that they could potentially be used for algae cultivation to recycle CO2.
Henriksson N., 2013. Effects of carbon dioxide on biomass and species composition of a natural Baltic Sea spring bloom community. BSc thesis, Linnaeus University, 30 p. Thesis (restricted access).