Aquatic Pest Profiles Flashcards
Planktonic Algae
Ex: Chlamydomonas, Chlorella, Euglena, Closterium, Anacystis
Description: Microscopic organisms which when present in great numbers are called an algae bloom
Damage: Large blooms can cause overshading of desirable plants and may also cause oxygen depletion, leading to fish kills
Filamentous Algae
Ex: Spirogyra, Anabaena, Oscillatoria
Description: Single algal cells that form long visible chains, threads, hairs, or filaments. Filaments often intertwine to form a mat resembling wet wool. “Pond scum”
Damage: Sudden die offs of dense mats can cause water quality problems and oxygen depletion, as well as aesthetic and odor issues as the algae decomposes.
Erect Alage
Ex: Chara, Nitella
Description: Submerged erect algae often confused with submerged flowering plants. Chara has a foul, must, garlic-like odor and a grainy or crunchy texture, with whorled branches with 6-16 small branchlets around each node. Nitella is soft to the touch and does not smell, and has forked, bushy branches.
Damage: Erect algae can cause problems for swimmers and boaters if large dense blooms are allowed to exist. Large-scale diebacks can cause oxygen depletion and fish kills.
Didymo
Ex: Didymosphenia geminata
Description: Invasive. Technically a diatom, a type of unicellular algae encased in a layer of silica. When present in large numbers, forms brown mats in the water, or long flowing streamers of algae that may appear white at the end. Brown, beige, or white, but NOT green, and is scratchy or rough to the touch. Both epiphytic (attaches to plants) and epilithic (attaches to rocks).
Damage: Can form a thick brown layer in the water that smothers rocks and plants, reducing good habitat for fish, invertebrates, and plants, and excluding other diatoms. Significant aesthetic affects are also a concern.
American Lotus
Description: Rooted floating; round, blueish leaves up to 2 ft in diameter. Flowers can be 10 inches across, yellow to yellowish-white with more than 20 petals; flower’s center is cone shaped.
Damage: Can be extremely aggressive in appropriate conditions, crowding out other species and lowering water quality.
Bladderwort
Description: Floating; no roots, but flowers on erect stems above the water. Flowers are yellowish, with three lobes and a spur beneath. Petioles are full of air, allowing them to float. Leaves whorled, with 4-10 lateral forking leaves giving the plant a delicate appearance.
Damage: Forms dense floating mats that can impede boaters and swimmers. Decomposing ends of the plant may cause oxygen depletion.
Duckweed
Description: Floating; very small, light green, free-floating plant. 1-3 leaves or fronds up to 1/8 inch long. A single root protrudes from each frond.
Damage: Aggressive invaders of ponds. Oxygen depletions and fish kills can occur.
Fragrant Water Lily
Description: Rooted floating; consists of round leaves on flexible stalks arising from large thick rhizomes. Leaves are bright green, 6-12 inches in diameter, with a slit along 1/3 of the leaf. Very fragrant bright white flowers with 25 or more petals and yellow centers arise on separate stalks, floating above the water.
Damage: Impedes water movement, causes sediment buildup, decreases recreational quality of waterways.
Giant Duckweed
Description: Floating; leaves are 1/8-1/4 inch long, with 1-4 light green leaves or fronds. Three or more root hairs protrude from each frond.
Damage: If colonies cover the surface of the water, oxygen depletions and fish kills can occur. Large colonies make recreational use less desirable.
Mosquito Fern
Description: Floating; small fern 1-2 inches wide. Leaves overlap, giving the surface a quilted appearance. A single root-like structure protrudes from each stem. Plants vary in color from green to red.
Damage: If these fern colonies cover the surface of the water, oxygen depletions and fish kills can occur.
Water Hyacinth
Description: Invasive. Floating; several leaves in rosettes are connected by stolons; prominent black roots hang from each rosette. Leaves are thick, leathery, 1-5 inches long by 1-4 inches wide, elliptical with parallel veins, held up by long, spongy petioles. Several blue to purple bluish flowers with a yellow blotch are clustered on tall spikes. Fruits are many-seeded capsules.
Damage: Dense growth clogs canals and water intakes and restricts navigation in rivers and lakes. Can negatively impact water quality and exclude native vegetation.
Water Lettuce
Description: Invasive. Floating; forms rosettes up to 5 inches across. Leaves are oblong, shaped like spades, and light green with velvety hairs and many prominent longitudinal veins. Flowers are few and enclosed in a leaflike hood.
Damage: Forms dense mats on the water surface, blocking waterways. Lowers oxygen concentrations and sunlight penetration. May be a breeding ground for mosquitoes.
Watermeal
Description: Floating; very small (less than 1mm) light green rootless plant. PERENNIAL.
Damage: Can be aggressive invader of ponds.
Watershield
Description: Floating; leaves are small (5 inches in diameter) oval to elliptical, with no slit at the stalk. Leaves have a distinctive gelatinous slime on the underside. Leaves are green on top, but stems and leaf undersides are reddish-purple. Flowers are small (up to 3/4 inch) dull-red with 3-4 petals, and rise above the surface. PERENNIAL.
Damage: Covers water, reducing light penetration and oxygen concentrations. Chokes waterways and reduce the recreational value of the water body.
Yellow Pond Lily (Spatterdock)
Description: Rooted floating; leaves arise from a large spongy rhizome. Leaves are 8-16 inches long by 10 inches wide, heart-shaped, with a slit from the stem. May float on the surface or stand above on thick round stalks. Flowers are spherical with 6-9 yellow petals. Fruits are oval with a flat top, greenish or yellow. PERENNIAL.
Damage: Crowds out native species, impedes water flow and recreational use.
Hydrilla
Description: Invasive. Submerged; healthy leaves are bright green, while stressed leaves may be brown or yellow. Long, slender stems. Leaves are up to 2 cm long, have a midrib on the underside with one or more sharp teeth along it, and leaf margins are saw-toothed, found with whorls of 4-8. Often confused with native elodea and Brazilian elodea, but leaves of other species are usually much smoother than hydrilla. Will produce tubers, unlike most other species. Roots to the bottom in depths up to 25 ft. If present, flowers are fine, white, and appear singly on threadlike stalks. PERENNIAL (reproduces through vegetative fragments, tubers, turions, and possibly seed.
Damage: Forms dense, single species stands that impact water flow, sedimentation, water quality, and recreational use.
American Pondweed
Description: Submerged; pondweed has both floating and submerged leaves in an alternate pattern. Leaves are elliptical to oval, 4-7 inches long and 2 inches wide, standing on long petioles. Fruits appear on brownish-reddish spikes that stand above the water’s surface. PERENNIAL.
Damage: Plants may grow rampantly and invade deep water, pushing out more diverse species.
Brazilian Elodea (Egeria)
Description: Invasive. Submerged; leaves and stems are bright green, and whole plants appear very leafy. Leaves are minutely serrated, 1-3 cm long and very thin, found in whorls of 4-8. Flowers are white and very small, with 3 petals, rising above the water’s surface. Roots to the bottom in depths up to 20 ft. PERENNIAL, reproduces only vegetatively.
Damage: Forms dense, single species stands that restrict water flow, trap sediment, and impact water quality.
Coontail
Description: Submerged; dark olive green, rootless, form dense colonies. Leaves are stiff, whorled, serrated. Tips of branches are crowded with leaves, giving it a feathery, fur-like appearance. Flowers are tiny, and appear at the joint between the leaf and the stem. PERENNIAL, reproduces by seed and fragmentation.
Damage: Large stands will decrease the recreational and habitat uses of the water body, and will also crowd out more desirable or appropriate species.
