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This image of Amphipleura pellucida was taken using an Olympus SPlanapo 100X/1.40, Zeiss 1.40 achro plan condenser, DIC, Wratten 47 deep blue filter, The Imaging Source 1024X768 digital camera, mosaic of 4 images (every image is an average of 32 frames in order to reduce noise). Software Panorama Maker 3.0 and Photoshop.
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Diatoms are algae which live in little glass boxes or frustules - rather like little petri dishes. Pennate diatoms are motile, and rely on, we believe, the excretion of mucus through a slit in the wall - the slit is the raphe and runs down the flat faces of the petri dishes (frustules in diatom terminology). The frustule is perforated with tiny holes to allow the diatom to excrete waste products, and pick up nutrients, dissolved gases etc. from the surrounding water. The one is seriously asymmetric. Phase contrast.
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Ribadelago de Franco, Castille and Leon, Spain
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Lumbreras, La Rioja, Spain
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Original nib drawing made by Frenguelli.
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Amphiprora (am-fee-pro-ra). Pennate diatoms are usually regarded as boat shaped, although some of the boats have very odd shapes. They can usually glide. This particular form is very common in sediments - the form apparently allowing the cell to penetrate through the pores of the sediments. Although enclosed in a siliceous shell, the shell of these rather delicate diatoms is flexible. The plastids contain chlorophylls a and c which gives the yellowy-brown colour. Phase contrast.
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Lumbreras, La Rioja, Spain
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Pennate diatom seen in girdle view. The cells are enclosed in siliceous valves. There are typically two valves - a top one and a lower one, and they are joined together with fine bands or girdle strips. This image is a view from the side and shows the girdle strips. Differential interference contrast.
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Mahide, Castille and Leon, Spain
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Pennate diatoms. The cells are enclosed in siliceous valves. There are typically two valves - a top one and a lower one, and they are joined together with fine bands or girdle strips. With plastids containing chlorophylls a and c (they are stramenopiles after all). Genera and species distinguished largely by the shape of the organism and the pattern of pores and sculptings of the siliceous shell or frustule. Pennate diatoms are important in intertidal and illuminated subtidal sediments in marine ecosystems and primary producers. Pennate diatoms are capable of movement, relying on the raphe to produce thrust. Movement benefits diatoms which may move towards the light, recover their location after disturbances by overlying water currents, wave actions, animal burial and so on. Several species illustrated. Phase contrast.
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Ribadelago de Franco, Castille and Leon, Spain
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Lumbreras, La Rioja, Spain
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Lumbreras, La Rioja, Spain
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Live Amphipleura pellucida shown under a light microscope.
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Villoslada de Cameros, La Rioja, Spain
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Ribadelago de Franco, Castille and Leon, Spain
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