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2020:groups:g2:start [2020/01/07 14:06] prado2020:groups:g2:start [2024/01/09 18:45] (current) – external edit 127.0.0.1
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 ===== Introduction ===== ===== Introduction =====
  
-{{  http://media.nordicmicroalgae.org/large/Planktothrix%20agardhii_1.jpg?100|Planktothrix agardhii}} Trophic interactions between phytoplankton (primary producers) and zooplankton (consumers) govern the flow of energy in aquatic systems. //Planktothrix agardhii// is an abundant aquatic cyanobacteria. This small phytoplanktonic species displays resistance to grazing by zooplankton such as //Daphnia galeata// because of its filamentous morphology, production of toxins and low nutritional value. However, //Planktothrix// can be infected and killed by the obligate parasite //Rhizophydium megarrhizum//, a chytrid fungus. These parasitic fungi, in turn, have a free-living stage that is highly nutritional and an important food source for zooplankton. Thus, parasitic //Rhizophydium// fungi create an important trophic link between cyanobacteria and zooplankton termed the "mycoloop"+{{http://media.nordicmicroalgae.org/large/Planktothrix%20agardhii_1.jpg?100  |Planktothrix agardhii}} Trophic interactions between phytoplankton (primary producers) and zooplankton (consumers) govern the flow of energy in aquatic systems. //Planktothrix agardhii// is an abundant aquatic cyanobacteria that can form algal blooms in freshwater lakes
  
-Additionally, when //Planktothrix//  cells are infected by //Rhizophydium//, their morphology and nutritional value change and, consequently, they become more edible to //Daphnia//. This way, //Rhizophydium// infection facilitates the grazing of //Planktothrix// by //Daphnia//, further strengthening the trophic link between phytoplankton and zooplankton. +{{  https://upload.wikimedia.org/wikipedia/commons/4/4e/Daphnia_pulex.png?100|Daphnia sp.}}  This small phytoplanktonic species displays resistance to grazing by zooplankton such as //Daphnia galeata// because of its filamentous morphology, production of toxins and low nutritional value. However, //Planktothrix// can be infected and killed by the obligate parasite //Rhizophydium megarrhizum//, a chytrid fungus. These parasitic fungi, in turn, have a free-living stage that is highly nutritional and an important food source for zooplankton. Thus, parasitic //Rhizophydium// fungi create an important trophic link between cyanobacteria and zooplankton termed the "//mycoloop//" (Agha et al. 2016). 
 + 
 +{{:2020:groups:g2:polycentric-chytrid-feeding-on-filamentous-cyanobacteria-after-karling-1977.png?150 |Chytrid fungi feeding on filamentous cyanobacteria, Karling, J.S. (1977) Chytridiomycetarium Iconographia.}}Additionally, when //Planktothrix//  cells are infected by //Rhizophydium//, their morphology and nutritional value change and, consequently, they become more edible to //Daphnia//. This way, //Rhizophydium// infection facilitates the grazing of //Planktothrix// by //Daphnia//, further strengthening the trophic link between phytoplankton and zooplankton. 
  
 ===== Assignment ===== ===== Assignment =====
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 Propose and analyse a mathematical model that describes the trophic dynamics among cyanobacteria (primary producer/host), chytrids (parasite/prey) and zooplankton (grazer/predator).  Propose and analyse a mathematical model that describes the trophic dynamics among cyanobacteria (primary producer/host), chytrids (parasite/prey) and zooplankton (grazer/predator). 
  
-===== Questions & Suggestions =====+===== Suggested questions =====
  
   - Under what conditions can cyanobacteria, chytrid fungi and zooplankton coexist?   - Under what conditions can cyanobacteria, chytrid fungi and zooplankton coexist?
   - Under what conditions do cyanobacteria blooms form?   - Under what conditions do cyanobacteria blooms form?
 +
 +Further well-grounded questions from the group are welcome.
 +
  
 ===== References ===== ===== References =====
2020/groups/g2/start.1578406003.txt.gz · Last modified: 2024/01/09 18:45 (external edit)