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Sirvi Autor "Freiberg, René (advisor)" järgi

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    Kirje
    Pigment-based chemotaxonomy – efficient tool to quantify phytoplankton groups in lakes and coastal sea areas
    (Eesti Maaülikool, 2019) Tamm, Marju; Nõges, Tiina (advisor); Freiberg, René (advisor); Newell, Silvia (opponent); Herlemann, Daniel (pre-opponent)
    All members of the aquatic food web rely either directly on indirectly on the autotrophic phytoplankton. The distribution and dynamics of phytoplankton groups reflects a number of things: rate of eutrophication, biogeochemical cycling and formation of the potentially harmful algal blooms. Therefore we are bound to quantify the community composition of phytoplankton. These measurements are complicated since the population growth of the phytoplankton can be explosive and the distribution is patchy. Traditionally phytoplankton is quantified via microscopy which is expensive, time-consuming, subjective and requires highly skilful specialists. This thesis aims to improve phytoplankton monitoring by using algal pigments. This method relies on a fact that all photosynthetic algae have chlorophyll a in their cells that helps to convert light energy into chemical energy. Additionally all algae have accessory pigments that help to capture the light from different wavelenghts. Since there are hundreds of different accessory pigments they can be used as markers for phytoplankton taxonomic groups. Therefore we can quantify different algal groups by measuring the amount specific marker pigments. These measurements are fast and easily automated. Biggest complication is that the amount of accessory pigments is not constant and depends on several environmental factors – e.g. irradiance, nutrients. My work aims to analyse the relationship of marker pigments and phytoplankton groups in various aquatic envrionments. Our studies in lake Võrtsjärv and coastal areas of Baltic Sea have demonstrated that phytoplankton pigments are a powerful tool in monitoring. Quantification of phytoplankton goups via pigments is faster, cheaper, more objective and precise than with traditional approach. Additional perk of pigment-based chemotaxonomy is that the smallest fraction of phytoplankton – picoplankton, which is left out of microscopy analysis, can be easily studied with this method.