AQUATIC WEED AND ITS TYPES. AQUACTIC WEED Aquatic weeds can be broadly defined as unwanted and undesirable plants which grow and reproduce in an aquatic. - презентация

1 AQUATIC WEED AND ITS TYPES

2 AQUACTIC WEED Aquatic weeds can be broadly defined as unwanted and undesirable plants which grow and reproduce in an aquatic environment (Lawrence, 1966)

3 Classification of Aquatic Weeds Two groups of aquatic plants: – 1. Algae - simple plants without roots, leaves or stems. They reproduce by cell division, fragmentation, or by spore formation. – 2. Vascular plants - plants having roots, stems, leaves, and flowers. There are four classes - submersed, free-floating, rooted floating, emerged plants.

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5 Aquatic Weeds - Algae Three types: – 1. Microscopic algae - single celled or colonial algae. Also referred to as Phytoplankton when suspended in water. During the daylight - give off oxygen, During night - remove oxygen. If overabundant - fish kill due to oxygen removal from water - referred to as an algal bloom - the result of too much fertilizer in pond.

6 Aquatic Weeds - Algae Three types: – 1. Microscopic algae – 2. Filamentous algae - thread-like filaments that form mats on surface of the pond. As algae photosynthesize, oxygen gets trapped in the body causing them to rise to the surface as clumps. Examples: - Spirogyra - bright green and slimy- Cladophora - cotton mat algae, due to texture - Pitophora - horsehair coarse

7 Aquatic Weeds - Algae Three types: – 1. Microscopic – 2. Filamentous – 3. Chara - looks more like a plant with leaves needle-like and arranged in whorls along the stem. Musky odor and gritty surface due to calcium deposits. Also called stonewort

8 Submersed Plants

9 Aquatic Weeds - Vascular Plants – Submersed Plants Four Groups: 1. Submersed plants - rooted to the bottom and completely submersed except for flowers which may extend above the water. Often referred to as moss. Identification based upon: * Leaf arrangement * Leaf shape

10 Aquatic Weeds - Vascular Plants Submersed Plants - Alternate Leaves: – One leaf per node – PONDWEEDS - (Potamogeton sp.) Curly Leaf Pondweed Sago Pondweed Leafy Pondweed

11 Free Floating