Transcript Stream Fish Diversity Lab

Leaf
Decomposition
in Aquatic
Ecosystems
Terrestrial leaf litter is an important
nutrient source in aquatic eccosystems
Leaf Decomposition
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1) Leaves become waterlogged
and sink. May lose up to 42%
mass to leaching.
2) Colonization by bacteria and
fungi begins almost
immediately.
Leaf Decomposition con’t
3) Colonized by shredders (eat CPOM). Shredders convert CPOM
to FPOM. Grazers eat algae and diatoms (FPOM).
Crayfish
Crane
fly
Amphipod
Snail
Water penny
Diatoms
Leaf Decomposition con’t
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4) Collector-gatherers (eat FPOM).
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5) Collector-filterers (eat FPOM).
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Bacteria and fungi continue to break down
CPOM and FPOM.
Mayfly
Midge
Black fly
Caddisfly
Predators eat other invertebrates
Hellgrammite
Dragonfly
Damselfly
Purpose of this lab
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Question 1: Does presence of macroinvertebrates
accelerate leaf decomposition?
Purpose of this lab
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Question 2: Do leaves containing more carbon
degrade more slowly?
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Cellulose and lignin are resistant to decomposition.
Methods
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Prepare coarse-mesh maple, coarse-mesh oak, finemesh maple, and fine-mesh oak bags.
Place and secure bags in stream/pond.
Remove bags after ~1 month.
Rinse macroinvertebrates from leaves and allow leaves
to dry.
Count macroinvertebrates and sort according to
functional feeding groups.
Weigh and estimate leaf material lost.
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