FACTORS REGULATING BENTHIC ALGAE

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FACTORS REGULATING BENTHIC ALGAE
Authors Szymon Daraszewicz Nadiia
Melnykova Supervisor Maria Kahlert
Erken Labolatory, Norr Malma June July 2005
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Introduction

• Aim
• Investigation of the regulating factors
• Climate warming impact projection
• Why is it important?
• Algae contribute to primary production
• Topic is poorly studied

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Project structure

• Observation
• Lab experiment
• Comparison of the lakes

Light quality Light quantity
Biomass Biodiversity Living abundance
Water chemistry Trophic level
Growth
Light quality
Biomass Biodiversity Living abundance
Light quality Trophic level
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Hypothesis

• Light quality is more important regulating factor
  of biomass biodiversity than light quantity
• Light quality is the main regulating factor of
  growth
• Trophic level has no impact upon benthic algae

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Sampling site
Max. depth 21m Av. Depth 8.3m Area 1.46km2

• Lake Largen

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Field work

• Lake Largen

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Method

• Water samples were analysed for
• Colour
• pH
• Total P and N
• Alkalinity
• Conductivity
• Dissolved N P
• Chlorophyll

• Sediment samples were analysed for
• Particle organic/inorganic matter
• Chlorophyll A,B,C
• Carotenes
• Biodiversity

• Computer programmes used
• Light quality and quantity model
• (Strombeck 2001)
• Statistica 6.1
• Correletion analysis
  
• Significance tests

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Results - Observation
Blue p0.67 Red p0.65 Light intesity
p0.70 Yellow p0.70
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DF vs Standard Method

• Poorly calibrated DF apparatus!

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Results Lab experiment

• Control group showed the greatest growth rate
• At blue and red light condition algae were
  growing fastest.
• Green yellow light conditions showed similar
  results to no light condition.

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Comparison of the lakes

• Red
• (p0.05, p0.01, p0.38)
• N/P ratio
• (p0.16, p0.12, p0.17).
• Blue
• (p0.51, p0.47, p0.19)
• Yellow-green
• (p0.06, p 0.11, p0.39)

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Conclusion

• First hypothesis partially verified
• Second hypothesis positively verified
• Third hypothesis possibly false
• (N/P and red light are not independent factors)

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Discussion

• Results are not coherent
• Study suffers from methodological flaws
• Research needs to be replicated
• Further studied should
• Investige greater number of lakes
• Analyse greater number of replicates per depth