Aquatic Plants Aquatic Ecology Mr. Werner

PLANTS (MACROPHYTES) TAXONOMY and DIVERSITY Macro-algae (Chara) – Several forms Flowering Plants – 2 dozen families (several hundred species) 4 categories: Floating unattached, Floating attached, Submerged, Emergent

AQUATIC MACROPHYTE HABITAT Attached, Floating, submerged, emergent, SWIMMING AND ESCAPE BEHAVIOR none FEEDING PREFERENCES AND BEHAVIOR Photosynthesis LIFE CYCLE AND DIAPAUSE The seed bank ECONOMIC IMPORTANCE AND MANAGEMENT Large: Ecologically important Sometimes nuisances

EXTERNAL STRUCTURE, APPEARANCE and ANATOMY Typical plant structures: roots (rhizome, holdfast) stem (single cell in macro-algae) leaves flowers “Plants are inside-out animals.” Tim Allen

The importance of aquatic macrophytes in freshwater systems Aquatic macrophytes play a vital role in ecosystems. They are primary producers and an important food source. They provide a substrate for algae and shelter for invertebrates and young fish. They offer nesting sites or birds and mammals They aid in nutrient cycling. They catch sediments and help stabilize river and stream banks.

Rhizomes

1. Floating unattached plants Roots, if present, hang free in the water and are not anchored to the bottom. Duckweed

2. Floating attached plants …have leaves which float on the surface, but their stems are beneath the surface, and their roots anchor the plant in the substrate.

3. Submerged plants … the entire plant is below the surface. Elodea nuttallii

4. Emergent aquatic macrophytes …have roots below and stems and leaves above the water’s surface. Sedges - Carex

a.Sedge - Wetlands b.Grass – Emergent c.Lily pads – Floating Attached d.Sundew - Emergent e.Duckweed – Floating Unattached a. b. c. d. e. For Picture see Fig. 5.6 p.136 in Textbook

Chara (macroalgae) Pond weeds (narrow- leafed water weed) Boad-leafed water weed Utricularia (bladder wort) Milfoil (Myriophyllum) Representative of aquatic submerged macrophytes For Picture see Fig. 5.7 p.136 in Textbook

Life Cycle Reproduce once a year Macro-algae = release motile gametes Flowering Plants = flowers on stalks, pollinated by wind or insects/birds. Seeds mature during warm season & enter diapause stage in winter.

The speed of the water determines the type of plants found. Fast water encourages low, encrusting forms

Lentic Systems Slow flowing or lentic bodies can have large leafy forms present.

Factors affecting plant growth Light is the most important factor in determining the presence of plants Light levels beneath the surface can be affected by many factors such as: – Depth – Turbidity (sediment) – Shading (trees etc.) – Water color (chemical staining) – Ice formation