Transcript Aquatic Fungi & Leaf Breakdown

Katie Seymore
 Two different aquatic fungi
 Leaf breakdown and fungi
 Bacteria and fungi relationship
 The essential role of leaf conditioning
 Aquatic hyphomycetes and aero-aquatic fungi
 Form-class fungi
 Most Ascomycetes, fewer Basidiomycetes, one Oomycete
 Secondarily adapted to aquatic life
 Convergent evolution events
 Similar ecological roles
 Leaf breakdown
 First described by Ingold
in the 1940’s
 Produce and release spores
underwater
 Mostly in streams-
moving, oxygenated water
Conidia
 Described by Beverwijk 1950’s
 Amphibious
 Propagules trap air and float for dispersal
 Mostly in temporary waters, low oxygen
Fall- conidia germinating
Winter/spring- grow
Summer- make propagules
 Trap air
 Hydrophobic
encrustation
 Many different forms
 Important ecological role
 Release nutrients to aquatic ecosystems
 Increase leaf’s N content
 Lowers leaf mass
 Amount of lignin (polymer in cells walls) content
controls how fast leaf decomposes
 available carbon
 Tannins amounts also big deal
(phenol compounds)
 Overall generalists
 Can specialize
 Combined exoenxzymes of all fungi on a leaf help
speed breakdown
 Linked mycelium
 Two different leaves
 Help by Sharing
 Harm by sending incorrect cues to healthy mycelium
 Bacteria are often talked about, but have only
a small role
 Bacteria cannot penetrate leaf, only on outside
 Fungi are 95% of microbial biomass
 Fungi perform better without bacteria
 Bacteria has little growth without the
presence of fungi
 secondary compounds
 Key links in the food web
 Breakdown tough compounds in the leaves
 Different leaves condition at different times
 Make leaves suitable for detritivores, like
caddisflies
 Caddisflies consume leaf parts
 but really, the fungi in the leaf is more nutritious then
the leaf itself
 Caddisflies taste test leaves
 Will avoid unconditioned parts, eat only the best spots
 Leaves can be over conditioned by fungi
 Out of nutrients
 Fungi dead
 Mycotoxins
 Instead of conditioning the leaf, some fungi make it
less palatable
 Defense against getting eaten
 Allochthonous material very important for aquatic food
webs
 Organisms in vernal ponds have limited time to grow
before ponds dry out, so any increase in food quality
helps!
 Fungi play a role in food availability throughout the year
with different conditioning times for different leaves
 Two main forms of aquatic fungi
 Awesome convergent evolution
 Important for food supply in aquatic ecosystems
 Key to nutrient release and detrital breakdown
 http://www.botanik.univie.ac.at/mycology/images/Poster
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Oslo.jpg
footage.shutterstock.com
http://ww2.coastal.edu/vgulis/conidia.htm
http://www.mycolog.com/chapter11b.htm
http://www.mycolog.com/chapter11b.htm
www.thinklongislandfirst.com
http://www.naturalheritage.state.pa.us/VernalPool_Ecolog
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http://fungi.life.illinois.edu/about/mitosporic_fungi
http://super-marioworld.webnode.com.br/products/random-images-4/
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