Pond Ecological Analysis

Pond Organisms

Last updated: 2/20/2009

Freshwater Ecological Analysis Project • The following are organisms that we have found in samples of a primary stream that originates on our campus and empties into Nancy Creek which is a tributary of the Chattahoochee River. Our campus is located in Fulton county, GA. • These identifications should be considered preliminary. The classification systems are not always standard. • The background information slides are, for the most part, quotes from Wikipedia and a few other sources.

Oscillatoria (Cyanophyta)

Oscillatoria (Cyanophyta) • •

From Wikipedia, the free encyclopedia Genus: Oscillatoria Oscillatoria is a genus of filamentous cyanobacteria which is named for the oscillation in its movement. Filaments in the colonies can slide back and forth against each other until the whole mass is reoriented to its light source. It is commonly found in watering-troughs waters, and is mainly blue-green or brown-green. Oscillatoria is an organism that reproduces by fragmentation. Oscillatoria forms long filaments of cells which can break into fragments called hormogonia. The hormogonia can grow into a new, longer filament. Breaks in the filament usually occur where dead cells(necridia) are present. Oscillatoria uses photosynthesis to survive and reproduce.

Spirulina (Cyanophyta)

Spirulina (Cyanophyta or Cyanobacteria) •

From Wikipedia, the free encyclopedia

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Spirulina is the common name for human and animal food supplements similar to Chlorella and Aphanizomenon flos-aquae (Blue Green Algae.) Spirulina comes from two different species of cyanobacteria: Arthrospira platensis, and Arthrospira maxima. These and other Arthrospira species were once classified in the genus Spirulina. There is now agreement that they are a distinct genus, and that the food species belong to Arthrospira; nonetheless, the older term Spirulina remains the popular name. Spirulina is cultivated around the world, and is used as a human dietary supplement as well as a whole food and is available in tablet, flake, and powder form. It is also used as a feed supplement in the aquaculture, aquarium, and poultry industries.[1]

Bacillus (Eubacteria)

Bacillus (Eubacteria) • From Wikipedia, the free encyclopedia •

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This page is about the bacterial genus. For the class, see Bacilli. For rod-shaped bacteria in general, see Bacillus (shape). For the stick insect genus, see Bacillus (insect). Bacillus is a genus of rod-shaped bacteria and a member of the division Firmicutes. Bacillus species are either obligate or facultative aerobes, and test positive for the enzyme catalase.[1] Ubiquitous in nature, Bacillus includes both free-living and pathogenic species. Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods. These characteristics originally defined the genus, but not all such species are closely related, and many have been moved to other genera.[2]

Hyalotheca (Chlorophyta)

http://protist.i.hosei.ac.jp/PDB/Images/Chlorophyta/Hyalotheca/

Hyalotheca (Chlorophyta) •

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“Hyalotheca dissiliens is a colonial, filamentous desmid, rather commonly occurring in all kinds of standing freshwaters, provided that those are not too acid/oligotrophic. Despite its wide distribution the species under discussion is frequently overlooked. Particularly on a superficial view, Hyalotheca may be easily confused with other, nonConjugatophycean filamentous green algae. The reason is that cells hardly show any morphological differentiaton, such as a distinct sinus, which is characteristic of most desmid species. Moreover, cells join each other across almost their total breadth so that it looks as if we are dealing with a true (parenchymatic) filament rather than with a filamentous colony. Actually, cellular constitution of two semicells appears predominantly from the presence of two large, axile, radiating chloroplasts (one in each semicell). Only on closer inspection a very slight median constriction of the cell is to be distinguished. Cell filaments of Hyalotheca dissiliens use to be enclosed by a thick mucilage sheath. Such a sheath contributes to the colonial coherence and increases the chance of dispersal as the filaments readily stick to migratory water fowl, insects etc.”

• http://www.desmids.nl/maand/english/may eng03.html

Desmidium (Chlorophyta)

http://protist.i.hosei.ac.jp/pdb/Galleries/USA1999/Species/Desmidium_2.html

Desmidium (Chlorophyta) •

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“Desmidium* is one of the filamentous desmid genera characterized by rather firm intercellular connections: filaments are only to be disrupted by robust mechanical pressure. From the Netherlands some four species are known, of which Desmidium swartzii is the most common. Cells of this species are triangular in apical view. After cell division daughter cells stick together so that the filament in question increases in length. Moreover, cell filaments are markedly twisted, to be seen from a gradual shift in position of the cellular lobe facing the observer. In case of conjugation (almost) all cells in the paired filaments are sexually activated, resulting into a series of zygospores coupling the empty cell filaments. * The genus name of Desmidium - derived from the Greek word 'desmos' (= ribbon, chain or bond) - presumably gave rise to the family name of Desmidiaceae.” http://www.desmids.nl/maand/english/augeng03.html

Spirogyra (Chlorophyta)

m/imgres?imgurl=www.plingfactory.de/Science/GruKlaOeko/Teichleben/Algen/Spirogyra.jpg&imgrefurl=http://www.plingfactory.de/Science/GruKlaOeko/Teichleben/A

Spirogyra (Chlorophyta) •

From Wikipedia, the free encyclopedia

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Spirogyra is unbranched with cylindrical cells connected end to end in long green filaments. The cell wall has two layers: the outer wall is composed of cellulose while the inner wall is of pectin. The cytoplasm forms a thin lining between the cell wall and the large vacuole it surrounds. Chloroplasts are embedded in the peripheral cytoplasm; their numbers are variable (as few as one). The chloroplasts are ribbon shaped, serrated or scalloped, and spirally arranged, resulting in the prominent and characteristic green spiral on each filament. Each chloroplast contains several pyrenoids, centers for the production of starches, appearing as small round bodies. Spirogyra is very common in relatively clean eutrophic water, developing slimy filamentous green masses. In spring Spirogyra grows under water, but when there is enough sunlight and warmth they produce large amounts of oxygen, adhering as bubbles between the tangled filaments. The filamentous masses come to the surface and become visible as slimy green mats. Mougeotia and Zygnema are often found tangled together with Spirogyra.[1]

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Conjugation in Spirogyra Male cell

Conjugation tube

zygospore

Female cell

Conjugation in Spirogyra •

From Wikipedia, the free encyclopedia

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Spirogyra can reproduce both asexually and sexually. In asexual reproduction, fragmentation takes place, and Spirogyra simply undergoes intercalary mitosis to form new filaments. Sexual Reproduction is of two types: Scalariform conjugation requires association of two different filaments lined side by side either partially or throughout their length. One cell each from opposite lined filaments emits tubular protuberances known as conjugation tubes, which elongate and fuse, to make a passage called the conjugation canal. The cytoplasm of the cell acting as the male travels through this tube and fuses with the female cytoplasm, and the gametes fuse to form a zygospore. In lateral conjugation, gametes are formed in a single filament. Two adjoining cells near the common transverse wall give out protuberances known as conjugation tubes, which further form the conjugation canal upon contact. The male cytoplasm migrates through the conjugation canal, fusing with the female. The rest of the process proceeds as in scalariform conjugation. The essential difference is that scalariform conjugation occurs between two filaments and lateral conjugation occurs between two adjacent cells on the same filament. Spirogyra uses photosynthesis for the production of food.

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Zygnema (Chlorophyta) zygospores

http://images.google.com/imgres?imgurl=www.plingfactory.de/Science/GruKlaOeko/Teichleben/Algen/Spirogyra.jpg&imgrefurl=http://www.plingfactory.de/Sc 6lr%3D%26ie%3DUTF-8%26client%3DREAL-tb%26sa%3DN

Zygnema (Chlorophyta) • •

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. World distribution: Throughout the world. “A genus of about 140 species, all freshwater. It forms unbranched filaments, with each cell containing a pair of stellate chloroplasts. Each chloroplast possesses a single, conspicuous pyrenoid. Sexual reproduction takes place by conjugation, with the fusion of two amoeboid gametes in a conjugation canal formed between adjacent filaments, forming a thick-walled zygote. There are no flagellated reproductive cells. 14 species are recognised in the British Isles by Johnson (in John et al., 2002), their identification depending on reproductive features. The related genus, Zygnemopsis, with two British species, both rare, also cannot be distinguished from Zygnema when only vegetative. Many of the species have broad ecological requirements, occuring in ponds, streams, ditches and similar waterbodies, often forming extensive 'blanket weed' growth. Z. stellinum is given as a fairly common species in ditches and in moorland pools.” http://www-biol.paisley.ac.uk/bioref/Chlorophyta/Zygnema.html

Closterium (Chlorophyta)

http://www.micrographia.com/specbiol/alg/desmi/desm0100.htm

Closterium (Chlorophyta) • •

From Wikipedia, the free encyclopedia Closterium

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[Morphology Elongated cylindrical, often lunate unicells comprising of two symmetrical semicells. Single, axial chloroplasts with many pyrenoids in each semicell. Very conspicuous vacules at the ends of the cell with CaSO4 (Gypsum) crystals "dancing" around within them.

Netrium (Chlorophyta)

http://www.desmids.nl/

Netrium (Chlorophyta) • “Netrium is a single-celled saccoderm desmid. The cells are usually elongate and cylindrical with rounded or truncate ends, but may also be elliptical or fusiform in shape. The cells can excrete large amounts of mucilage. Each cell has two or four large, axial chloroplasts that appear frilly due to their elaborate lobes and ridges. The chloroplasts are stellate in cross-section and contain one or many pyrenoids. The nucleus is located between the chloroplasts in the center of the cell.” • http://silicasecchidisk.conncoll.edu/LucidKeys/Carolina_ Key/html/Netrium_Main.html

Cosmarium (Chlorophyta)

Cosmarium (Chlorophyta) •

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“Cosmarium is a single-celled placoderm desmid. The cells are deeply divided in the middle by a short isthmus that contains the nucleus. The two semicells are rounded in front view and flattened, oval, or elliptic in side view. The older half of the cell wall secretes mucilage, while the younger half is lifted off of the substrate at a slight angle. The mucilage swells as it absorbs water and propels the cell forward. The cell wall may be smooth with pores or ornamented with granules, pits, or warts. The vegetative cells usually do not have spines. Each semicell has at least one central chloroplast (usually 2 or 4) with pyrenoids. Cosmarium sometimes produces thick-walled resting cells. Triradiate cells with three semicells have sometimes grown in collections or cultures. “ http://silicasecchidisk.conncoll.edu/LucidKeys/Carolina_Key/html/Co smarium_Main.html

Micrasteria (Chlorophyta)

http://www.desmids.com

Micrasteria (Chlorophyta) • •

From Wikipedia, the free encyclopedia Desmids Desmids are an order (Desmidiales) of green algae, comprising around 40 genera and 5,000[1] to 6,000[2] species, found mostly but not exclusively in fresh water. Most are unicellular, and are divided into two compartments separated by a narrow bridge or isthmus. Desmids assume a variety of highly symmetrical and generally attractive shapes, which provide the basis for their classification. Each compartment has one chloroplast, and no flagella. Sexual reproduction occurs through a process of conjugation, also found among the Zygnematales. These two groups are closely related, and may be united as the division Gamophyta. The desmids are sometimes treated as members of the Zygnematales, but more often given the separate order Desmidiales.

Microspora (Chlorophyta)

Microspora (Chlorophyta) •

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“From Greek mikros, "small" + spora, "spore" Microspora is an unbranched, filamentous green alga with cylindrical or swollen cells. The ends of the filaments often have holdfast cells to attach to the substrate. The cell wall is is made up of H- shaped pieces of open cylinders with intermediate septa, which overlap to enclose the protoplast of each cell. Microspora has parietal, reticulate chloroplasts that lack pyrenoids and contain starch. Microspora is similar in morphology to Tribonema, which has at least two pale green or golden disklike chloroplasts that do not contain starch. The phylogeny of Microspora is somewhat uncertain, and further molecular research would help to clarify its taxonomic placement.” http://silicasecchidisk.conncoll.edu/LucidKeys/Carolina_Key/html/Mi crospora_Main.html

Volvox (Chlorophyta)

http://www.csus.edu/indiv/r/reihmanm/images_for_lab_4.htm

Volvox (Chlorophyta) • •

From Wikipedia, the free encyclopedia

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Volvox is one of the best-known chlorophytes and is the most developed in a series of genera that form spherical colonies.[1] Each mature Volvox colony is composed of numerous flagellate cells similar to Chlamydomonas, on the order of 1000–3000 in total, and embedded in the surface of a hollow sphere or coenobium made of a gelatinous glycoprotein.[2] The cells swim in a coordinated fashion, with a distinct anterior and posterior poles. The cells have eyespots, more developed near the anterior, which enable the colony to swim towards light. The individual algae in some species are interconnected by thin strands of cytoplasm, called protoplasmates.[3] An asexual colony includes both somatic (vegetative) cells, which do not reproduce, and gonidia near the posterior, which produce new colonies through repeated division. The daughter colonies are initially held within the parent coenobium and have their flagella directed inwards. Later, the parent disintegrates and the daughters invert. In sexual reproduction two types of gametes are produced. Volvox species can be monoecious or dioecious. Male colonies release numerous microgametes, or sperm, while in female colonies single cells enlarge to become oogametes, or eggs.[1][4] Antonie van Leeuwenhoek first reported observations of Volvox in 1700. [5]

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Pennate Diatoms Phylum Chrysophyta

Pinnularia hilseana

Navicula gregaria Pinnularia brandeliiCleve http://www.bgsu.edu/departments/biology/facilities/algae/html/P_and_G_ESF.html

Navicula • •

From Wikipedia, the free encyclopedia

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Genus: Navicula Navicula is a genus of boat-shaped microbes (microorganisms) that are a type of Phytoplankton or algae — primarily aquatic, eukaryotic, photosynthetic organisms, ranging in size from a single cell. Navicula is a diatom. The Navicula genus of diatoms comprises more than 10,000 species. Navicula is Latin for "small ship".

Pinnularia (Chrysophyta) • • • • •

From Wikipedia, the free encyclopedia Habitat Pinnularia is a fresh Water alga, usually found in ponds and moist soil. They can also be found in springs, estuaries, sediments and in the ocean. Cell Wall and Valves Pinnularia are unicellular. The cell is elongated and elliptical. The cell wall is chiefly composed of pectic substances and is impregnated with silica. Therefore, their wall becomes very hard. Their wall is composed of two halves called valves. These halves overlap like petri dish. The margins of the two valves are covered by a connecting band called cingulum. The two valves with their inner protoplasts are called frustule. The frustule has two views. The surface view is called valve view and band view is called girdle view. The outer larger valve is called epitheca. The smaller inner valve is called hypotheca. The cell is covered by mucilaginous layer. The surface of valve has minute pores or pits. It produces characteristic markings on the surface of valves. These markings are bilaterally symmetrical. The marking free area is called axial field. The markings are arranged in linear rows. The axial field contains a longitudinal slit raphe. The raphe is not continuous throughout the length of the valve. It has circular thickening called central nodules in the centre. Similar Thickening also present at the outer ends of raphe These are called polar nodules.

Tabellaria (Chyrsophyta)

Tabellaria (Chyrsophyta) •

“A common freshwater genus, often forming zigzag colonies. The cells are often lying in girdle view with visible septa and the appearance of the cell is rectangular. The plastids can be seen to lie between the septa. In valve view the cell shows the swollen poles and central region. Along the margin of the valve there are small spines and there is an apical pore field at both poles. Reported is a single rimoportula found near the centre of the valve (River Diatoms, a multi-access key). A distinguishing feature of T. flocculosa is that the swelling of the poles are smaller than the inflation at the centre of the valve. Collected with a 60 micron plankton net from between Union Lake and a beaver dam south of Union Lake. PH of (middle): 6.7-6.8, temp=12.3C. (Oct 6-06), Kinmount, Ontario, Canada: N 44 46.755’ W 078 31.663’. November 10, 2006; “

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https://www.biomedia.cellbiology.ubc.ca/cellbiol/user/scripts/qry_media_id.p hp?media_id=3049

Suriella (Chrysophyta)

Description Suriella “Cells solitary. Frustules heteropolar in valve and girdle view, bilaterally symmetrical. Cells lie in valve or girdle view and isolated valves always in valve view. Valves bilaterally symmetrical, heteropolar, oval, with the broader pole smoothly rounded but the narrower pole slightly pointed, becoming almost circular in the smallest specimens. Transverse striae visible, somewhat irregular, interrupted along the midline of the valve by a narrow, linear or irregular, hyaline area. The valve face is slightly folded at the inner margins of the fibulae, differentiating central and marginal zones. Raphe system fibulate (the raphe itself is impossible to detect in LM), marginal, occupying the whole perimeter of the valve. Some fibulae rib-like, tapering, extending in from the margin by approximately a fifth of the (maximum) valve width. Those fibulae that are aren't extended inwards are tiny bars difficult to detect in LM. There is one chloroplast per cell, consisting of two large plates, often lobed at their margins, connected by a narrow isthmus that lies near one end of the cell. The plates lie against the valves and, when seen in valve view, appear to fill all except the cell periphery.” http://craticula.ncl.ac.uk/EADiatomKey/html/taxon1380 0100.html

Euglena (Euglenophyta)

http://mtlab.biol.tsukuba.ac.jp/WW W/PDB/Galleries/USA1999/Species/Euglena_2.jpg

Euglena (Euglenophyta) • •

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From Wikipedia, the free encyclopedia They are single-celled organisms. Currently, over 1000 species of Euglena have been described. Marin et al. (2003) revised the genus to include several species without chloroplasts, formerly classified as Astasia and Khawkinea. Euglena sometimes can be considered to have both plant and animal features. A euglena is a protist that can eat food like animals do (partly heterotrophic) and can make food like plants do (partly autotrophic). Euglena can surround a particle of food and eat it (phagocytosis). Many Euglena contain chloroplasts and chlorophyll a and b. Euglena live in fresh water, salt water and in marine-like environments. Many Euglena are able to move by using a flagellum, a long whip-like structure. When the water dries up, a euglena forms a protective wall around itself and lies dormant in the form of a spore until the environment improves. It reproduces by mitosis, splitting into parts, like amoeba.

Amoeba (Sarcodina)

http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Cells/cells.htm

Amoeba (Sarcodina) • • •

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From Wikipedia, the free encyclopedia History The amoeba was first discovered by August Johann Rösel von Rosenhof in 1757.[4] Early naturalists referred to Amoeba as the Proteus animalcule after the Greek god Proteus who could change his shape. The name "amibe" was given to it by Bory de Saint-Vincent[5], from the Greek amoibè (αμοιβή), meaning change.[6] Anatomy Anatomy of an amoeba The cell's organelles and cytoplasm are enclosed by a cell membrane, obtaining its food through phagocytosis. Amoebae have a single large tubular pseudopod at the anterior end, and several secondary ones branching to the sides. The most famous species, Amoeba proteus, is 700-800 μm in length but the species Amoeba dubia is as large as a millimeter, and visible to the naked eye. Its most recognizable features include one or more nuclei and a simple contractile vacuole to maintain osmotic equilibrium. Food enveloped by the amoeba is stored and digested in vacuoles. Amoebae, like other single-celled eukaryotic organisms, reproduce asexually via mitosis and cytokinesis, not to be confused with binary fission, which is how prokaryotes (bacteria) reproduce. In cases where the amoeba are forcibly divided, the portion that retains the nucleus will survive and form a new cell and cytoplasm, while the other portion dies. Amoebas also have no definite shape.[7]

Astramoeba (Sarcodina)

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Astramoeba Page updated 11/8/02 “A very old genus, raised by Vejdovsky in 1881 (Schaeffer, 1926), the type species is A. radiosa but since has been reclassified on numerous occasions (see for Schaeffer, 1926 for a discussion of the more ancient literature). Page discussed A. torrei in the context of Mayorella, yet unlike any other Mayorella, A. torrei produces cysts. There does not seem to be a uniting feature of the amoebae described in the genus Astramoeba, save perhaps that they produce long pointed pseupods but then so do many others. Described species:A. flagellipodia (Schaeffer, 1926). Freshwater. c50mm in length while in locomotion. Has fewer than 10 pseudopods some of which are described as having characteristics between a flagella and a normal pseudopod. No E.M. study has been carried out and as far as I know, no cultures of this amoeba presently exit, so the cytoskeletal components of these structures are unknown. The description given by Scheaffer seems superficially to resemble the genus Flagellipodium. A. radiosa Described by several workers but its not certain if they were looking at the same amoeba. A. stella (Schaeffer, 1926). Freshwater. 25-50mm in diameter with many blunt cylindrical pseudopods projecting at all directions. Locomotion uncertain and slow. “ http://www.bms.ed.ac.uk/research/others/smaciver/astramoeba.htm

Difflugia (Sarcodina)

Test (shell)

pseudopods

Difflugia (Sarcodina) • •

From Wikipedia, the free encyclopedia Genus: Difflugia LeClerc, 1815 Difflugia is one of several genera of amoebozoa that produce shells or tests from granules of sand. These are swallowed by the cell and during the process of budding or fission they pass into the daughter, where they are joined by organic cement. The test has a single terminal opening. Difflugia are particularly common in marshes. The Difflugia use pseudopods to move around. It is a heterotroph and it engulfs its food.

Arcella (Sarcodina)

Test

http://www.isis.de/members/~ralfwagner/Amoeben_Sonnentierchen.html

Arcella (Sarcodina) “ Taxonomy (ITIS) • • •

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• Length: 50-60 mm • Description: Arcella is a beautiful, testate (shelled) amoeba. The test is circular, transparent, with a central aperture (hole). It's color is light yellow when young and its getting darker while aging. Usually, Arcella has two, sometimes more nuclei (visible well using phase contrast). Arcella can often be found among detritus, usualy only empty tests. • Similar genera: Centropyxis “ http://www.pirx.com/droplet/gallery/arcella.html

Centropyxis (Sarcodina)

http://protist.i.hosei.ac.jp/taxonomy/sarcodina/Lobosea/Testacealobosia/Genus/Centropyxis/Centropyxis.jpg

Centropyxis • Introduction • “More than 130 species and many varieties have been described. Many of these descriptions are incomplete. Type species: Centropyxis aculeata (Ehrenberg, 1838). • •

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In this genus we find two different shell types: Test bilaterally symmetrical, rounded, flattened more at front than at rear; ventral face flat; often spines at sides and rear. Pseudostome: ventral, anterior, roundish, dorsal and ventral lips recurved, invaginated, often bridged (see title illustration, br and Fig. 1) from ventral margin to dorsal face of the test. Shell can be organic or constructed with mineral particles or diatoms. Shape, number of spines and size extremely variable. These species prefer freshwater habitats. Typical representativea are C. aculeata or C. discoides (title illustration and Fig. 1).” For more info go to: http://tolweb.org/Centropyxis/124498

Euglypha (Sarcodina)

Euglypha (Sarcodina) • • Length: 60 mm • Description: Euglypha is a testate amoeba. The test is clear and ovoid, has scales.”

• http://www.dropletmicroscopy.org/gallery/euglypha.html

Actinophrys (Sarcodina)

http://www.isis.de/members/~ralfwagner/Amoeben_Sonnentierchen.html

Actinophrys (Sarcodina) •

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“Among the most familiar of the heliozoa, sun animalcules, are members of the family Actinophryidae. This group comprises two genera: Actinophrys and Actinosphaerium. In common with other heliozoa, Actinophrys possesses a spherical shape and radiating pseudopodia called axopodia (sing. axopodium). As a result of the globular form and numerous tapering pseudopodia, this organism looks like a minute sun under the microscope, especially when using the phase contrast technique. This protozoon has one nucleus located in the cell center. Its many false feet are attached by their bases to the nuclear membrane surface and protrude to the outside. These pseudopodia are supported by axial rods (microtubular axonemes). Its axopodia have a number of indistinct extrusomes; these are special organellae for capturing or killing prey and for protection from its predators, which flow along its arms. An Actinophrys has no internal skeleton, cilia or flagella. A whole cell is highly vacuolated especially in the peripheral area . Generally, the cell body is approximately 40-50 microns in diameter and some vary from 30-90 microns.” http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopyuk.org.uk/mag/artfeb02/ccactino.html

Spirostomum (Ciliophora)

http://www.hokoon.edu.hk/nature/ecology/a_level/source/22.html

Spirostomum (Ciliophora) • •

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From Wikipedia, the free encyclopedia Ehrenberg, 1833 Spirostomum is a member of the protist kingdom. It is an animal-like protist, or protozoan which feeds on bacteria. It is found in pond water. Spirostomum is a Ciliate, which use cilia to move through water. Spirostomum is an unusual protozoan. It is large for a protist. It can grow up to 0.17 in (3 mm) which is large enough to be seen with the naked eye. Though a unicellular organism, it has multiple nuclei. Also, Spirostomum can contract its body to 1/4 of its length in 6 to 8 milliseconds, which is the fastest contraction known in any living cell.[1]

Stentor (Ciliophora)

Stentor (Ciliophora) • •

From Wikipedia, the free encyclopedia Stentor are a genus of filter-feeding, heterotrophic ciliate protozoa, representative of the heterotrichs. The body is generally horn-shaped, hence the association with the Greek herald and the former name "trumpet animalcule", with a ring of prominent cilia around the anterior "bell" that sweep in food and aid in swimming. Stentor are very common in freshwater lakes and streams, usually attached to algae and other detritus. Some reach several millimeters in length, making them among the largest single celled organisms. Stentor can come in different colors. As in many freshwater protozoans, , the stentor has a contractile vacuole. Because the concentration of salt inside Stentor and in the surrounding freshwater is different, Stentor must store water that enters it by osmosis and then discharge it from the vacuole. Stentors can regenerate, and small fragments can grow into full organisms. Stentor can live symbiotically with certain species of green algae. After being injested, the algae live on while their erstwhile predator-cum-host absorbs nutrients produced, while the algae, in turn, absorb and feed on the Stentor's metabolic wastes. Stentors react to outside disturbances by contracting into a ball.

Paramecium (Ciliophora)

http://pantransit.reptiles.org/images/1998-08-24/

Paramecium (Ciliophora) • From Wikipedia, the free encyclopedia • •

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Paramecia, also known as Lady Slippers, due to their appearance, are a group of unicellular ciliate protozoa, which are commonly studied as a representative of the ciliate group, and range from about 50 to 350 μm in length, Simple cilia cover the body, which allow the cell to move with a synchronous motion (like a caterpillar). There is also a deep oral groove containing inconspicuous compound oral cilia (as found in other peniculids) used to draw food inside. They generally feed on bacteria and other small cells. Osmoregulation is carried out by a pair of contractile vacuoles, which actively expel water absorbed by osmosis from their surroundings. Paramecia are widespread in freshwater environments, and are especially common in scums. Paramecia are attracted by acidic conditions. Certain single-celled eukaryotes, such as Paramecium, are examples for exceptions to the universality of the genetic code (translation systems where a few codons differ from the standard ones).

Frontonia (Ciliophora)

Frontonia (Ciliophora) • • •

• Length: 150-250 mm • Description: Frontonia has an ovoid, flattened body, rather dark.

Nassula (Ciliophora)

Nassula (Ciliophora) • • •

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• Length: 80 mm • Description: Nassula is a medium size ciliate. It has very vivid colors due to the partially digested food in the food vacuoles. There is a quite distinct cyrtos in the anterior end. This protozoan can swim rather fast and it can be difficult to photograph. “ http://www.pirx.com/droplet/gallery/nassula.html

Blepharisma (Ciliophora) “The Blepharisma is a rather large, common protozoan and belongs to the Phyllum Ciliophora. It is from 150-300 um long and is rose colored.”

Blepharisma (Ciliophora) • “Blepharisma is a heterotrich ciliate and a microphagus filter feeder. It usually eats bacteria found in decomposing vegetation by drawing them into its vortex of membranelles that surround its buccal cavity (mouth). The food is then passed through the cytostome and enclosed in food vacuoles which are distended to the posterior end of the cell.” • http://www.zoology.ubc.ca/courses/bio332/Labs/ CiliateProject/blepharisma/bleph1web.html

Euplotes (Ciliophora)

Euplotes (Ciliophora) •

http://www.microscopemicroscope.org/applications/pondcritters/protozoans/ciliphora/euplotes.htm

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“The Euplotes belongs to the Phyllum Ciliophora. They are from 80-200 um long. Euplotes is an interesting ciliate with a transparent body. It has large cilia that is tufted together to form cirri and a bandlike macronucleus (the big backward "C" shown inside the body).

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From the side, Euplotes is quite thin and can be seen using its cirri and "walking" along objects. ”

Epistylis (Ciliophora)

Common epizoite on copepods

http://protist.i.hosei.ac.jp/taxonomy/Ciliophora/Oligohymenophorea/Genus/Epistylis/index.htm l

Epistylis (Ciliophora) • “The Epistylis belongs to the Phyllum Ciliophora. They are from 200-250 um long and colonies can reach up to 2mm long. • They are a stalked ciliate which looks similar to the Vorticella and Carchesium. They are different, however, in that the stalk does not have a myoneme which is the spring like contracting element. The Epistylis therefore cannot contract like the Vorticella and Carchesium.” •

http://www.microscope-microscope.org/applications/pondcritters/protozoans/ciliphora/epistylis.htm

Vorticella (Ciliophora) “ The Vorticella is a protist (protozoan) and belongs to the Phyllum Ciliophora. It is a very interesting, stalked ciliate with an inverted bell shape. The stalk contains a contractile fibril called a myoneme. When stimulated, it shortens, causing the stalk to coil like a spring.

”

http://www.microscope-microscope.org/applications/pond-critters/protozoans/ciliphora/vorticella.htm

Vorticella (Ciliophora) •

From Wikipedia, the free encyclopedia

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Vorticella is a genus of protozoa, with over 16 known species. They are stalked inverted bellshaped ciliates, placed among the peritrichs. Each cell has a separate stalk anchored onto the substrate, which contains a contracile fibril called a myoneme. When stimulated this shortens, causing the stalk to coil like a spring. Vorticella mainly live in freshwater ponds and streams— generally anywhere protists are plentiful. Reproduction is by budding, where the cell undergoes longitudinal fission and only one daughter keeps the stalk. The free daughter becomes a telotroch, which swims until it finds suitable substrate to fix and develop its own stalk. They reproduce by fission. Also known as cell division. They are also capable of reproducing by conjugation. Conjugation is a form of sexual reproduction where two vorticella attach at the oral groove and swap DNA. Other genera such as Carchesium resemble Vorticella but are branched or colonial. Vorticellas sometimes stay in clusters. Some people learn these groups as colonies, but they are not true colonies because each vorticella has its own individual stalk. This allows the vorticella to detach from the cluster at any time. Common species Vorticella campanula (most common

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Stylonichia (Ciliophora)

Stylonichia (Ciliophora) • • • • •

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“The Smithsonian/NASA Astrophysics Data System Stylonichia mytilus and the Lunar Periods Gray, Ernest Nature, Volume 167, Issue 4236, pp. 38 (1951). DURING a recent investigation at the University Botany School, Cambridge, of the association of ciliate protozoa and bacteria in a chalk stream, Styl nichia mytilus in common with other ciliate protozoa exhibited a series of `pulses', or maximum waves when it spread down the stream, and minimum phases when it could be found only in the upper reaches. Forms in binary fission or conjugation were sometimes noted at the end of the maximum phase, whereas the minimum phase was generally marked by the appearance of small forms. The pulse of Stylonichia could not be related to any constant climatic or physical factor (rainfall, pH, temperature, etc.) or to total bacterial numbers at 22° C. or any particular group of bacteria. However, the maximum phase often occurred about a week to ten days after one of the lunar periods. From May to December 1947, the maximum phases occurred on twelve out of thirteen occasions a week to ten days after a new moon or a full moon: the greatest maximum peak was attained nine days after a new moon in July and four days after a full moon in December. By contrast with the dry weather and clear nights of 1947, the year 1948 was wet and dull. Stylonichia was only recorded between May and September, yet on five occasions it reached its maximum phase on an average eight days after a new or a full moon. “ http://adsabs.harvard.edu/abs/1951Natur.167...38G

Condylostoma (Ciliophoria)

Condylostoma (Ciliophoria) • “Heterotrich ciliates, large ciliates; elongate body, often pointed posteriorly; highly contractile “ • http://www.eol.org/pages/2973947

Lacrymaria (Ciliophora)

Lacrymaria (Ciliophora) • “One of the most unusual microscopic animals amongst the wide range of protozoans is Lacrymaria olor, a very small creature - typically 100 microns long, that lives in freshwater ponds. Its name means 'tear of a swan', which is an excellent and apt description of both its general shape, and one of its identifying traits; for this animal possess the ability to extend its head outwards by means of what looks like an elongating neck. And just as a swan is able to manipulate its neck in many directions, Lacrymaria is able to maintain the same type of agility over its extensibility. “ •

http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopyuk.org.uk/mag/art98/tear1.html

Halteria (Ciliophora)

http://microscope.mbl.edu/scripts/microscope.php?func=browseAlpha&letter=H&taxa=Halteria

Halteria (Ciliophora) • “Halteria is a small oligotrich ciliate. Thanks to the equitorial cirri, it can move in a "jumpy" fashion. Common, but difficult to photograph.” • http://www.pirx.com/droplet/gallery/halteria .html

Colpidium (Ciliophora)

Colpidium (Ciliophora) • Colpidium, Rabbit of the Microcosm Micronaturalist's Note Book Written and Photographed by Bruce J. Russell •

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“The cells swim in a spiral, rotating around their long axis, but they stop this "free swim" as they near their tightly packed sisters. Centering on a growing cluster of cells, I change to the 10X objective and adjust the iris to create higher contrast image. A quick scan of the drawings in Jahn, How to Know the Protozoa, convinces me that this is Colpidium, a bacteria feeding ciliate, belonging to one of the main branches of ciliate evolution, the holotrichs. If Paramecium is a deer and Didinium is a wolf, then Colpidium must be a rabbit. All of the clusters are surrounding bits of detritus shimmering with bacteria.” http://www.ebiomedia.com/Note-Book/Colpidium-Rabbit-of-theMicrocosm.html

Loxodes (Ciliophora)

Loxodes (Ciliophora) • Bütschlii, 1830 Family: Body long, flat, with beak-like anterior rostrum; oral area in long ventral groove behind rostrum Müllerian vesicles in endoplasm. Genus: Oral area round, behind rostrum, leads into tubular cavity (Illustrated Guide, 1985). Species (magnus Stokes): Extended about 700 μm long; dark brown; twelve to twenty or more Müllerian vesicles in a row along dorsal border (Kudo, 1966). • http://protist.i.hosei.ac.jp/PDB/Galleries/USA1999/Specie s/Loxodes.html

Urocentrum (Ciliophora)

Urocentrum (Ciliophora) “A relative of the paramecium, Urocentrum is a rotund ciliate slightly bifurcated by a two distinct bands of cilia and sporting a tufted "tail" of fused cilia on its posterior. The organism spins on this tail, swimming rapidly in a slightly irregular spiral. It commonly occurs in decaying pond vegetation in which it feeds on bacteria and particles of organic matter”. • http://micro.magnet.fsu.edu/moviegallery/pondscum/prot ozoa/urocentrum/t1/urocentrum01.html.

Peranema (Mastigophora)

Peranema (Mastigophora) • • •

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“Peranema are small flagellates and range in size from 20-70 um in diameter. They are very active predators and scavengers. This flagellate is common in waters rich in organic nutrients, especially in water in which decay is taking place. The single flagellum projects straight forward, and a rapid rotation of its extreme end pulls the Peranema smoothly through the water. The body of the Peranema can undergo extreme contraction and distortion as it moves. Peranema have been seen inside the bodies of dead rotifers and are said to absorb nutrients through their outer pellicle. In addition, they can ingest quantities of detritus, bacteria, algae and even large organisms by expansion of the cytostome -- a cavity which lies at the base of the flagellum.” http://www.microscope-microscope.org/applications/pondcritters/protozoans/mastigophora/peranema.htm

Anisonema (Mastigophora)

Anisonema (Mastigophora) • •

“Anisonema Dujardin, 1841 Family: Colorless body; two flagella, one directed anteriorly and the other usually posteriorly; stigma absent. Genus: Generally ovoid; asymmetrical; plastic or rigid; a slit-like ventral furrow; flagella at anterior end; cytopharynx long; contractile vacuole anterior; nucleus posterior (Kudo, 1966). Lightly striated; trailing flagellum longer than anterior one (How to know the protozoa, 1979). “ http://protist.i.hosei.jp/PDB/Images/Mastigophora/Anisonema/index. html

Petalomonas (Masigophora)

Petalomonas (Masigophora) • •

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“Petalomonas Stein Genus: Only 1 emergent flagellum; locomotory flagellum directed anteriorly, straight, during swimming; colourless, phagotrophic; no eyespot; rigid, solitary, ovoid, usually flat, with several keels; freshwater (Illustrated Guide, 1985). Oval or pyriform; not plastic; pellicle often with straight or spiral furrow; a single flagellum; many species (Kudo, 1966).” http://protist.i.hosei.ac.jp/Movies/htmls/Mastigophora/Petalomonas/i ndex.html

Cryptomonas (Mastigophora)

Cryptomonas (Cryptophyta) • From Wikipedia, the free encyclopedia • Genus: Cryptomonas Cryptomonas is the name-giving genus of the cryptomonads. It is common in freshwater habitats and often forms blooms in greater depths of lakes, or during winter beneath the ice. The cells are usually brownish in color, and have a slit-like furrow at the anterior. They are not known to produce any toxins and are used to feed small zooplankton, which is the food source for small fish in fish farming.

Planaria (Platyhelminthes)

Planaria (Platyhelminthes) • •

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From Wikipedia, the free encyclopedia Planarian

Family: Planariidae Planaria are non-parasitic flatworms of the biological family Planariidae, belonging to the order Seriata. Planaria are common to many parts of the world, living in both saltwater and freshwater ponds and rivers. Some are terrestrial and are found on plants in humid areas. These animals move by beating cilia on the ventral dermis, allowing them to glide along on a film of mucus. Some move by undulations of the whole body by the contractions of muscles built into the body wall. They exhibit an extraordinary ability to regenerate lost body parts. For example, a planarian split lengthwise or crosswise will regenerate into two separate individuals. The size ranges from 3 to 12 mm, and the body has two eye-spots (also known as ocelli) that can detect the intensity of light. The eye-spots act as photoreceptors and are used to move away from light sources. Planaria have three germ layers ( ectoderm, mesoderm, and endoderm), and are acoelomate (i.e. they have a solid body with no body cavity). They have a single-opening digestive tract, consisting of one anterior branch and two posterior branches in freshwater planarians. Because of this three-branched organization, freshwater flatworms are often referred to as triclad planarians.

Freshwater Nematode (Nematoda)

Freshwater Nematode (Nematoda) •

The Nematode Worms. “The nematodes are (along with copepod crustaceans) frequently described as "probably the most numerous animals on Earth". Some 80,000 species are described in the literature; possibly a million exist. They live in the soil, in the oceans and fresh water, and are found as internal parasites of most animals and many plants. It has also been said that if the animals of the world (apart from nematodes) were to dematerialize, their ghostly forms would be recognizable by the populations of nematodes which inhabit their tissues. There are certainly regions of the world where this would be true. “

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http://www.micrographia.com/specbiol/helmint/nematod/nema0100.htm

Freshwater Nematode (Nematoda) •

“The larger parasitic nematodes are referred to as roundworms, and the smaller parasites as threadworms. They have cylindrical bodies with no trace of segmentation. Chaetae (bristles) are seen only in some of the marine forms. The outer elastic cuticle is shed four times during the life of the worm. The mouth is at or near the anterior end, and the gut is a straight non-muscular tube with an anus at or near the posterior end. A muscular pharynx with a bulbous swelling towards the end is observable in the microscopic forms. The sexes are separate -- there is no hermaphroditism in the nematodes, but in certain species the females at certain stages reproduce parthenogenetically. They have no blood system, no respiratory system and no cilia. They also have no circular muscle, which means they are not capable of the contractions and constrictions shown by other worms, and typically move in a series of tight S-shaped curves which are fascinating to observe . “http://www.micrographia.com/specbiol/helmint/nematod/nema0100.htm

(Rotifera)

http://www.bruderhof.org/articles/images/microslides/40rotifer.htm

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From Wikipedia, the free encyclopedia The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696 and other forms were described by Anton van Leeuwenhoek in 1703.[1] Most rotifers are around 0.1-0.5 mm long, and are common in freshwater environments throughout the world with a few saltwater species. Some rotifers are free swimming and truly planktonic, others move by inchworming along the substrate, and some are sessile, living inside tubes or gelatinous holdfasts that are attached to a substrate. About 25 species are colonial (e.g., Sinantherina semibullata), either sessile or planktonic. Rotifers get their name (derived from Latin and meaning "wheel-bearer";[5] they have also been called wheel animalcules) from the corona, which is composed of several ciliated tufts around the mouth that in motion resemble a wheel. These create a current that sweeps food into the mouth, where it is chewed up by a characteristic pharynx (called the mastax) containing a tiny, calcified, jaw-like structure called the trophi. The cilia also pull the animal, when unattached, through the water. Most free-living forms have pairs of posterior toes to anchor themselves while feeding. Rotifaers have bilateral symmetry and a variety of different shapes. There is a well-developed cuticle which may be thick and rigid, giving the animal a box-like shape, or flexible, giving the animal a worm-like shape; such rotifers are respectively called loricate and illoricate.

(Rotifera)Un-identified Species

Rotaria (Rotifera)

Rotaria have reduced cilia and worm-like bodies. They are “hunters”.

Rotaria (Rotifera) • “Apart from using its ciliated crown for locomotion this Rotaria can also creep with its head and tail end. It uses the stickyness of the tail to attach itself to a surface while feeding. The feeding is done by making a current with the crown of cilia to sweep in food.” • http://www.microscopyuk.org.uk/mag/wimsmall/extra/rotif9.html

Rotaria “Jaws”

Rotaria are carnivores (unusual for rotifers)

Tardigrade (Tardigradia)

http://www.astrosurf.com/lombry/bioastro-adaptation5.htm

Tardigrade (Tardigradia) • •

Tardigrade From Wikipedia, the free encyclopedia

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“Tardigrades (commonly known as water bears) form the phylum Tardigrada, part of the superphylum Ecdysozoa. They are microscopic, water-dwelling, segmented animals with eight legs. Tardigrades were first described by Johann August Ephraim Goeze in 1773 (kleiner Wasserbär = little water bear). The name Tardigrada means "slow walker" and was given by Spallanzani in 1777. The name water bear comes from the way they walk, reminiscent of a bear's. The biggest adults may reach a body length of 1.5 mm, the smallest below 0.1 mm. Freshly hatched larvae may be smaller than 0.05 mm.”

Freshwater Oligochaete • Phylum Annelida Notice the desmids and diatoms

http://www.microscopy-uk.net/mag/indexmag.html?http://www.microscopy-uk.net/mag/artsep03/menu.html

Chaetogaster (Annelida)

Chaetogaster • •

From Wikipedia, the free encyclopedia

Genus: Chaetobaster Von Baer, 1827 •

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“The genus Chaetogaster belongs to the segmented worms (Annelida). It is classified in the subfamily Naidinae of the family (biology) Tubificidae in the order Oligochaeta. These are ca. 2-25 mm long transparent worms that are very common in fresh water and often form chains of individuals through asexual multiplication. Morphology Externally, the animals correspond to the general building plan of the Naidinae, however, in distinction from the other species, they bear setae (bristles) only on their ventral side, which is what gives them their name. The size of the worms, and of their setae too, is very variable even within single species.”

Aeolosomas (Annelida)

Water Mite (Arthropoda)

Water Mites • “Water mites can usually be found around the edges of ponds and lakes, either swimming in the vicinity of submerged plants or foraging on their leaves and stems. They are often brightly coloured, most often some shade of red or green, although blue, yellow and tan colours are also seen. The adults are rarely larger than about 2mm or smaller than 0.5mm. The largest known varieties can reach 8mm. Having eight legs and a pair of palps, they can appear at first to resemble tiny spiders, but closer inspection reveals that what would be cephalothorax and abdomen in a spider is in the water mites fused into a single body part having no sign of segmentation.” •

http://www.micrographia.com/specbiol/chelicer/mitaqua/mita0100.htm

Chironomid (midge) larva (Arthropoda)

http://www.microscopy-uk.net/mag/indexmag.html?http://www.microscopy-uk.net/mag/artsep03/menu.html

Chironomid (midge) larva (Arthropoda) • • •

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Chironomid Midges Richard M. Houseman Urban Entomology Extension Specialist “Chironomid midges (gnats) are small flies that range in size from 1/16 to 1/2 inch long. They range in color from light tan to light green to nearly black, depending on the species. Midges can be confused with mosquitoes, which are similar in size, appearance and habitat; however, midges are distinctly different from mosquitoes in their feeding habits. Mosquitoes possess a long, beaklike mouthpart that is used to suck blood, whereas most midges do not even feed as adults and never take a blood meal. In addition, midges typically have “fuzzy” antenna, a characteristic found, to a lesser extent, only in male mosquitoes.” http://extension.missouri.edu/explore/agguides/pests/g07402.htm

Cypris (Arthropoda) Hydra

http://www.marksimmons.org/closeup/microimg/pages/ostracod_and_hydra.htm

Cypris (Arthropoda)

http://www.osaka-kyoiku.ac.jp/~ikuta/ostracods.html

Cypris •

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“Cypris are ostracods (a type of crustacean) and related to mussels and shrimp. They are small, about 1/2-2mm long, with a hard outer shell. In freshwater ponds they are usually found scuttling around among the debris at the shallow edges. They swim smoothly with appendages extended from between the two halves of their carapace (shell). When disturbed, they withdraw their limbs into their shell and clamp the halves tightly together. They can be seen with your lowest power (40X). Due to the opaque shell which makes it difficult to see their internal structure, just the antennae and limbs appear out of the gap between the two halves of the shell . Young specimens are the most rewarding for examination, as their shells are generally more transparent than those of the adults. They are food for the Hydra and small fish.” http://www.microscope-microscope.org/applications/pondcritters/animals/cypris.htm

Daphnia (Arthropoda) “ Daphnia, also called "water fleas" are found in the order Cladocera. Daphnia are crustaceans and related to lobsters, crabs and shrimp.”

http://www.microscope-microscope.org/applications/pond-critters/animals/daphnia.htm

http://www.btinternet.com/~stephen.durr/photographthree.html

Daphnia (Arthropoda) • •

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From Wikipedia, the free encyclopedia

“Genus: Daphnia Müller, 1785 Species Subgenus Daphnia Daphnia are small, planktonic crustaceans, between 0.2 and 5 mm in length. Daphnia are members of the order Cladocera, and are one of the several small aquatic crustaceans commonly called water fleas because of their saltatory swimming style (although fleas are insects and thus only very distantly related). They live in various aquatic environments ranging from acidic swamps to freshwater lakes, ponds, streams and rivers.”

Daphnia Head

Daphnia Abdomen

Camptocercus (Arthropoda) • Another caldocerean (water flea)

http://www.cnas.smsu.edu/zooplankton/Camptocercus.htm

Camptocercus • “The Genus Camptocercus is a group of small waterfleas…. Fine features of the postabdomen (number of denticles) are used to distinguish among species necessitating use of a high-powered light microscope at a minimum.” • http://www.glerl.noaa.gov/seagrant/GLWL/ Zooplankton/Cladocera/CladoceraKeyCa mptocercus.html

Cyclops (Arthropoda) “The cyclops has 5 pair of legs and a divided tail-like appendage called a furca. The Cyclops is very small about 2-3mm long with one black or red eye in the middle of its head. The cyclops is named after the one-eyed monster of Greek legend.”

http://www.microscope-microscope.org/applications/pond-critters/animals/cyclops.htm

Nauplius larvae of a copepod

Mama Copepod Releasing Nauplius Larvae

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“Nauplius larva The first, free-swimming, planktonic larva of most marine and some freshwater crustaceans. It has no evident segmentation. There is a single, median, nauplius eye at the front of the head. There are only three pairs of appendages, the first and second antennae, and the mandibles. The second antennae and mandibles bear swimming setae. Additional trunk segments and appendages appear with successive moults, the increments proceeding from anterior to posterior. The late nauplius stages are often called metanauplii. The term ‘post-larva’ is applied to all immature crustaceans when the full complement of segments and appendages have developed. Some or all larval stages are absent in certain groups of Crustacea, and in others they may be considerably modified. (Nauplius was the son of Poseidon, god of the sea.)” http://www.encyclopedia.com/doc/1O8-naupliuslarva.html

Canthocamptus (Arthropoda)

Physa (Mollusca)

http://www.applesnail.net/content/snails_various.php#Physidae

Physa • •

From Wikipedia, the free encyclopedia “Physa Scientific classification Kingdom: Animalia Phylum: Mollusca Class: Gastropoda Genus: Physa

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Physa is a genus of small, left-handed or sinistral, air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Physidae. These snails eat algae, diatoms and other detritus.

These small snails are quite distinctive, because they have shells that are sinistral, which means that if you hold the shell such that the spire is pointing up, then the aperture is on the left-hand side. The shells of Physa species have a long and large aperture, a pointed spire, and no operculum. The shells are thin and corneous and rather transparent.”

Lemna (Anthophyta) •

Duckweed

http://www.esu.edu/~milewski/aq_macr8.html

Lemna (Anthophyta) • • •

“Lemna From Wikipedia, the free encyclopedia Duckweed Common Duckweed (Lemna minor)

• Genus: Lemna L. Species About 13, including: •

Lemna is a genus of free-floating aquatic plants from the duckweed family. These rapidly-growing plants have found uses as a model system for studies in basic plant biology, in ecotoxicology, in production of biopharmaceuticals, and as a source of animal feeds for agriculture and aquaculture.”