Amount and variety of phytoplankton species in Lake Limmaren 2011 Authors: Maija Ķīkule, Latvia Greta Kaklytė, Lithuania Supervisor: Pia Larsson, Sweden

Aim To analyze nutrition status of Lake Limmaren by analyzing the phytoplankton living in the lake. To compare the lakes by combining results with the data gathered from lakes Erken and Largen by the other groups.

The biggest amount of phytoplankton should be found in Lake Limmaren, medium in Lake Erken and the smallest in Lake Largen. Cyanophyseae is expected in Lake Limmaren if pH is high. Hypotheses

Method Samples were taken from Lake Limmaren. Tube collector was used to collect them from the epilimnion layer. Using measurements of Lake’s Limmaren volume samples are mixed. Lugol was added to the water in beakers. Sedimentation chamber of 2ml volume and inverted microscope were used to count the amount of phytoplankton and to identify them.

Materials Tube collector with deep graduated line and sinker Lugol Sample bottles made of glass Bucket for stirring sample Funnel Labels for indicating the lake, or other identifier, test level, date. Sample bottle made of glass or plastic ml

Results Group of algaeAmount/0,5ml Diatomeae219 Chlorophyceae88 Cyanophyceae21166 Chrysophyceae19 Table 1. Groups and amount of phytoplankton individuals in the sample of Lake Limmaren.

DiatomeaeCyanophyceae

ChlorophyceaeChrysophyceae

SpeciesIndicator number % in the sample Anabaena20,24 Microcistys393,06 Pediastrum30,07 Stephanodiscus20,01 Total: 93,38 Table 2. Phytoplankton species in Lake Limmaren, that indicate eutrophication on a scale from 1-3.

LakeDepth (metres) Erken5,25 Largen5,77 Limmaren1,12 Table 3. Sechi depth in lakes Erken, Largen and Limmaren.

Lake Amount of phytoplankton /ml Erken1170 Largen11746 Limmaren95652 Table 4. The amount of phytoplankton individuals in lakes Erken, Largen and Limmaren.

Conclusion Seventeen different species of phytoplankton have been found. Four of them indicate the eutrophication and creates 93,38% of all species found in the sample. In Lake Limmaren the biggest amount of phytoplankton individuals have been found. Lake Limmaren has the highest nutrient status and is a eutrophic lake; Lake Erken has medium nutrient status and is a mesotrophic lake; Lake Largen has lowest nutrient status and is an oligotrophic lake.

Thank you four your attention!