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SUMMARY:Why Algal Blooms Suppress Duckweed Growth: Mechanisms Behind Growt
 h Inhibition
DTSTART;VALUE=DATE-TIME:20260930T080000Z
DTEND;VALUE=DATE-TIME:20260930T081500Z
DTSTAMP;VALUE=DATE-TIME:20260916T130451Z
UID:indico-contribution-2914@cern.ch
DESCRIPTION:Speakers: Sandor Szabo (University of Nyiregyhaza)\nIn duckwee
 d pond systems established either for biofiltration or biomass production\
 , excessive proliferation of planktonic algae reduces ecosystem services. 
 In this study we revealed those algal related mechanisms resulting duckwee
 d growth inhibition. We isolated 26 algal species from duckweed covered me
 socosms and measured their impact on axenic culture of Lemna gibba. At low
  duckweed coverage (<50%)\, 18 algal and cyanobacterial species significan
 tly reduced the growth rate of duckweed. The strongest inhibitory effects 
 were exerted by unicellular green algae. When the combined effects of domi
 nant algal species were examined\, all tested algae drastically inhibited 
 duckweed growth.  The elemental flux between the water\, algal biomass and
  Lemna fronds was followed in time. Algal biomass increase was closely ass
 ociated with the depletion of nutrients from the water column. In aquarium
  experiment\, under low and moderate nitrogen concentrations together with
  the absence of algal shading\, algae significantly inhibited the growth a
 nd chlorophyll content of Lemna by 60-80%. The algal inhibitory effect wea
 kened with increasing nitrogen concentration and under conditions of stron
 ger shading affecting the algae. Laboratory experiments demonstrated that 
 duckweed growth was most strongly inhibited by algal-induced nitrogen defi
 ciency\, followed by elevated pH (10.2)\, phosphorus deficiency\, and iron
  deficiency\, resulting in growth inhibition of 72%\, 52%\, 51%\, and 47%\
 , respectively. By the final day of the experiment\, both algal-induced ni
 trogen depletion and high pH completely reduced  duckweed growth.\n\nhttps
 ://indico.unina.it/event/117/contributions/2914/
LOCATION:Department of Agricultural Sciences of the University of Napoli F
 ederico II\, Portici\, Italy Sala Cinese
URL:https://indico.unina.it/event/117/contributions/2914/
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