Terrestrial leaf litter is an important nutrient source in streams.

Leaf Leaf Decomposition in Decomposition in

StreamsStreams

Terrestrial leaf litter is an important Terrestrial leaf litter is an important nutrient source in streamsnutrient source in streams

Leaf DecompositionLeaf Decomposition

1) Leaves become 1) Leaves become waterlogged and sink. waterlogged and sink. May lose up to 42% May lose up to 42% mass to leaching.mass to leaching.

2) Colonization by 2) Colonization by bacteria and fungi bacteria and fungi begins almost begins almost immediately.immediately.

3) Colonized by shredders (eat CPOM). Shredders convert 3) Colonized by shredders (eat CPOM). Shredders convert CPOM to FPOM. Grazers eat algae and diatoms (FPOM).CPOM to FPOM. Grazers eat algae and diatoms (FPOM).

Leaf DecompositionLeaf Decomposition

Water penny

Crayfish

Cranefly

Amphipod

Snail

Diatoms

4) Collector-gatherers (eat 4) Collector-gatherers (eat FPOM). FPOM).

5) Collector-filterers (eat FPOM). 5) Collector-filterers (eat FPOM). Bacteria and fungi continue to Bacteria and fungi continue to break down CPOM and FPOM.break down CPOM and FPOM.

Leaf DecompositionLeaf Decomposition

MayflyMayfly

Caddisfly

Midge

Black fly

Predators eat other invertebratesPredators eat other invertebrates

Damselfly

Dragonfly

Hellgrammite

Purpose of this labPurpose of this lab

  Question 1: Does presence of Question 1: Does presence of macroinvertebrates accelerate leaf macroinvertebrates accelerate leaf decomposition?decomposition?

Purpose of this labPurpose of this lab Question 2: Do leaves containing Question 2: Do leaves containing

more carbon degrade more slowly? more carbon degrade more slowly? Cellulose and lignin are resistant to Cellulose and lignin are resistant to

decomposition.decomposition.

MethodsMethods

  Prepare coarse-mesh maple, coarse-mesh Prepare coarse-mesh maple, coarse-mesh oak, fine-mesh maple, and fine-mesh oak oak, fine-mesh maple, and fine-mesh oak bags.bags.

Place and secure bags in stream/pond.Place and secure bags in stream/pond. Remove bags after ~1 month.Remove bags after ~1 month. Rinse macroinvertebrates from leaves and Rinse macroinvertebrates from leaves and

allow leaves to dry.allow leaves to dry. Weigh and estimate leaf material lost.Weigh and estimate leaf material lost. Count macroinvertebrates and sort Count macroinvertebrates and sort

according to functional feeding groups.according to functional feeding groups.