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Topic: Diatom

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In the News (Mon 22 Jul 19)

 Eureka: Diatoms Biology   (Site not responding. Last check: 2007-10-20)
Diatoms are either solitary and free, attached to a substratum by gelatinous extrusions or joined to each other in chains of varying length.
The deep-sea sediment record of marine benthic diatoms is useful to give evidence of displacement of shallow-water material or, when the diatoms are autochthonous, as an indicator of the depth to the sea floor at the time of sediment deposition.
The size of the benthic diatom flora is enormous, and in a large measure the ecology of the flora is unknown; ecologic field studies and ecologically oriented laboratory studies are few.
hjs.geol.uib.no /diatoms/Biology/index.html-ssi   (2678 words)

 Diatom filters
Diatom filters are used to "polish" water or spot clean an aquarium.
It is for this reason that diatom filters are only used short term and are not a permanent filter for the aquarium.
Due to the short periods that diatom filters are used, there is no opportunity for bacterial to develop and therefore they are probably the only purely mechanical filter available.
www.thatfishshop.com /equipment/diatom_filter.htm   (181 words)

Diatoms are delicate unicellular organisms that have a yellow-brown chloroplast that enables them to photosynthesize.
The cells of diatoms are ideal subjects for study under the microscope.
Pennate diatoms, which developed later in the earth's history, are able to locomote in a slow gliding fashion in the direction of the length of the cell.
www.microscopy-uk.org.uk /mag/wimsmall/diadr.html   (510 words)

 AWI: Research - Friedrich Hustedt Study Centre for Diatoms
Diatoms are generally the most important primary producers of marine and freshwaters.
For microscopists diatoms can present a challenge: sometimes the fine structure of the cell-wall detail can only be resolved by the finest objectives.
For comparison, diatom specialists have been able to create reference herbaria of described genera, species and varieties; one of the largest is the private collection of Friedrich Hustedt which, in 1968 was housed at the Institute für Meeresforschung in Bremerhaven (now the Alfred Wegener Institute).
www.awi-bremerhaven.de /Research/hustedt1.html   (228 words)

 References :: Antarctic Freshwater Diatoms
Kellogg, Davida E. and Kellogg, T.B. Diatoms of the McMurdo Ice Shelf, Antarctica: Implications for sediment and biotic reworking.
Diatoms of the saline lakes of the Vestfold Hills, Antarctica.
Diatom stratigraphy in a lake on Horseshoe Island, Antarctica: A marine-brackish-fresh water transition with comments on the systematics and ecology of the most common diatoms.
huey.colorado.edu /diatoms/about/references.php   (2442 words)

 Diatom - Wikipedia, the free encyclopedia
Diatoms (Greek: διά (dia) = "through" + τέμνειν (temnein) = "to cut", i.e., "cut in half") are a major group of eukaryotic algae, and are one of the most common types of phytoplankton.
Diatoms are a widespread group and can be found in the oceans, in freshwater, in soils and on damp surfaces.
Diatom cell walls are also called frustules or tests, and their two valves typically overlap one other like the two halves of a petri dish.
en.wikipedia.org /wiki/Diatom   (2239 words)

 basic diatom info
Diatoms are microscopic, single-celled or colonial plant-like organisms.
Diatom shells, or tests, are typically punctuated with numerous holes, or areolae, visible in the light microscope.
Diatoms are primary producers, carrying out photosynthesis using a large proportion of a the pigment fucoxanthin.
www.mbari.org /~conn/botany/diatoms/john/basics/descript.htm   (112 words)

Diatoms first appeared 200,000 million years ago, but flourished in Mesozoic times (ten million years ago) when they lived in such enormous numbers they left vast deposits of their shells up to three thousand feet thick.
Diatoms were placed under a new instrument and if their decorative lines appeared perfectly parallel or symmetrical, the technician had succeeded in making a distortion-free lens.
The variety of diatom shapes seems endless, although individuals of each species are identical to one another, except for size.
www.microscopy-uk.org.uk /mag/art97b/diatomb.html   (1212 words)

 JGI - Diatom Genome Reveals Key Role in Biosphere's Carbon Cycle
WALNUT CREEK, CA--The first genetic instruction manual of a diatom, from a family of microscopic ocean algae that are among the Earth's most prolific carbon dioxide assimilators, has yielded important insights on how the creature uses nitrogen, fats, and silica to thrive.
Nitrogen is crucial for diatom growth and is often in short supply in seawater, depending on ocean conditions.
Diatoms, with complete disregard for these presumed boundaries, have mixed and matched different attributes to create an incredibly successful microorganism.
www.jgi.doe.gov /News/news_9_30_04.html   (804 words)

 diatom sizes
Diatoms range in size from ten to 150 microns (millionths of a meter).
A diatom's weight increases greatly with size largely because of the additional weighty silica in the test.
Diatoms may grow to a point where they are too large for copepods and other zooplankton to eat.
www.mbari.org /staff/conn/botany/diatoms/john/special/size.htm   (234 words)

 Norwegian Coastal Diatoms: Why Diatom Microscopical Slides   (Site not responding. Last check: 2007-10-20)
Therefore diatom containing sediment material must be subjected to different cleaning methods that all try to remove non diatom material from samples: This material can be carbonate, organic matter (clumps, algal material, leaves and wood fragments), other acid soluble salts and minerals and non soluble mineral particles of clay to sand size.
Diatom frustules vary considerably in size from very small forms (several microns) to very large forms (more than 100 microns); they also are delicate to robust.
A diatom sediment floral analysis has to include all diatom species members regardless of their size: Therefore diatom sediment assemblages never must be subjected to sieve procedures or to size separation techniques.
hjs.geol.uib.no /diatoms2003/methods/why-diatom-slides.shtml   (405 words)

 JGI - Why Sequence a Diatom?
Diatoms are eukaryotic, photosynthetic microorganisms found throughout marine and freshwater ecosystems.
A defining feature of diatoms is their ornately patterned silicified cell wall, or frustule, which displays such species-specific fine-scale nanostructures that diatoms have long been used to test the resolution of optical microscopes.
The marine-centric diatom Thalassiosira pseudonana was chosen as the first eukaryotic marine phytoplankton (microscopic aquatic plant) for whole-genome sequencing for several reasons: this species has already served as a model for diatom physiology studies, the genus Thalassiosira is cosmopolitan throughout the world's oceans, and the genome is relatively small at 34 million base pairs.
www.jgi.doe.gov /sequencing/why/diatom.html   (150 words)

 What is a DIATOM?
In the course of growth a diatom extracts silica, the basic ingredient of common sand, from the water and converts it into a sort of external skeleton or frustule.
When a diatom dies, it settles to the bottom of the sea or lake and the organic part disintegrates leaving this siliceous skeleton, microscopic in itself and as full of tiny holes and passages as a sponge.
A cubic inch of diatomite contains millions of diatom fistulas, which is one way of dramatizing the fact that phenomenal growth over a period of ages was required to produce the vast deposits of diatomaceous earth.
www.diatomfilter.com /faq/diatom.htm   (464 words)

 More on Diatom Morphology   (Site not responding. Last check: 2007-10-20)
Diatoms are single-celled organisms which secrete intricate skeletons.
The skeleton of a diatom, or frustule, is made of very pure silica coated with a layer of organic material.
Through the raphe, the living diatom secretes mucilage, with which it may attach to a substrate or move by gliding over the substrate.
www.ucmp.berkeley.edu /chromista/diatoms/diatommm.html   (245 words)

 Vortex Diatom Filters
The Diatom Filter is equipped with a 3000 RPM motor shaft that is connected directly to the impeller.
When the flow from the exhaust tube is weak or the Diatom Filter is visibly dirty, it is time to clean and recharge the unit with a new charge of Diatom Filter Powder.
An "H" valve designed to allow the Diatom filter and other series of canister filters to be moved from one aquatium to another without breaking the intake siphon or disturbing the "diatom coat".
www.diatomfilters.com /contents/en-us/d1.html   (1697 words)

 New species of diatom discovered by UGA scientist
Prior to its discovery, the new species of photosynthetic algae was combined with another group of diatoms found in cold, pristine rivers and streams around the world.
Diatoms are microscopic, single-celled algae with cell walls composed of silica.
The newly described diatom is boomerang-shaped and lives in unusual pincushion-like colonies attached to rocks in the waves along the shore of Lake Superior.
www.uga.edu /news/artman/publish/printer_051201_DIATOM.shtml   (640 words)

 Diatom - MSN Encarta
Diatom, a member of the largest group of algae in the golden algae phylum.
Diatoms are unicellular but may occur as stalklike or branching colonies....
The Diatom Collection of the California Academy of Sciences
encarta.msn.com /encyclopedia_761575632/Diatom.html   (71 words)

 Diatoms   (Site not responding. Last check: 2007-10-20)
Diatoms are unique forms of algae that grow a silica shell that is preserved in underwater sediments after they die.
The diatom shell, called a frustule, is different for each species, so you can identify them through a microscope.
Diatoms live anywhere there is water, including lakes, streams, estuaries, oceans, and puddles.
www.stormbefore.com /diatoms.htm   (165 words)

 Geometry and Pattern in Nature 3: The holes in radiolarian and diatom tests.
In diatoms, the holes collectively take on the role of a sieve, a two-way filtration mechanism across which water and nutrient molecules permeate the cell.
It is interesting that, unlike the holes in similarly sized triangular diatoms, the perforations appear to be arranged in rows, rather than radiating from the centre; the fact that the diatom is three-sided does much to reinforce this illusion, and ensures that the “rows” will “read” correctly whichever side they are viewed from.
Where extreme close-packing or large vesicles have obviously not been present, the holes tend to be much reduced in size, and either be randomly scattered throughout the frustule, radiate from the centre, or lie in accordance with the lines of patterned ridging or protuberances present on the top surface of the frustule.
www.microscopy-uk.org.uk /mag/artfeb05/cbdiatoms.html   (1575 words)

 ISDR: DIATOM RESEARCH CONTENTS VOL 16 - 18   (Site not responding. Last check: 2007-10-20)
Moestrup and N. Lundholm Taxonomic notes on the marine diatom genus Pseudo-nitzschiain the Andaman Sea near the island of Phuket, Thailand, with a description of Pseudo-nitzschia micropora sp.
337?362); P.A Sims and R.M. Crawford The morphology and taxonomy of the marine centric diatom genus Paralia.
Diatoms (Bacillariophyta) in phototrophic biofilms colonising an Italian wastewater treatment plant (pp 241–255); Cubizolle, H., Serieyssol, K.K. and Argant, J. – Diatom and pollen evidence of Holocene vegetation dynamics and human impact on the Virennes Fenland (French Massif Central) (pp 257–273); Garcia, M.
www.isdr.org /vol-16-19.html   (2190 words)

 Diatom Home Page
Diatoms are unicellular algae generally placed in the family Bacillariophyceae.
The cell walls of these organisms are made of silica, and the varied shapes and beautiful ornamentation of these walls made the study of the diatoms and related siliceous organisms a favored pursuit of the microscopical pioneers.
The Diatom Collection of the California Academy of Sciences has sample locations, taxon collection, images, and a large diatom literature database on the WWW.
www.indiana.edu /~diatom/diatom.html   (1557 words)

 Can I run my Diatom Filter continuously?
The Diatom Filter is designed to operate continuously in salt or fresh water.
The Diatom will not filter out the oxygen, in fact it actually reduces carbon dioxide levels in the aquarium because of the speed of the impeller (3,000 R.P.M.).
The Diatom will not filter out the medicine as long as you are not using Super Char in it with the Diatom Powder.
www.diatomfilter.com /faq/continuously.htm   (385 words)

 MicroAngela - Diatom
There are a lot of diatoms in phytoplankton, which is made up of tiny, floating organisms in aquatic environments that use the energy of sunlight to make their own food by photosynthesis.
For reproduction, usually the diatom cell divides and then the shell separates and each half secretes a slightly smaller shell to fit inside the old one.
There are more than 8,000 known species of diatoms, mostly in fresh water or shallow ocean water.
www.pbrc.hawaii.edu /bemf/microangela/diatom.htm   (160 words)

 Diatom Filters for Aquariums and Ponds
Here the Diatom Filter store we strive to give you detailed info on the uses of diatomaceaous earth filters that will enable you to have a beautiful freshwater or saltwater aquarium.
The high quality diatom filter is great for great aquarium filtration systems that can be used 24 hours a day.
For the highest quality polished water use the diatom filter by vortex inneserspace.
www.diatomfilters.com   (492 words)

 Introduction to the Bacillariophyta   (Site not responding. Last check: 2007-10-20)
Diatoms have an extensive fossil record going back to the Cretaceous; some rocks are formed almost entirely of fossil diatoms, and are known as diatomite or diatomaceous earth.
For more information on diatoms and how they are used in environmental reconstruction, check out the Paleolimnology and Diatom Home Pages maintained by P. Roger Sweets at Indiana University, or visit the Algal Microscopy and Image Digitization Home Page at Bowling Green State University for many images of diatoms.
A general article on diatoms (15 Sep 1997) is available from the Mining Company.
www.ucmp.berkeley.edu /chromista/bacillariophyta.html   (254 words)

 ISDR: Diatom Research   (Site not responding. Last check: 2007-10-20)
Diatom Research is the journal of the International Society for Diatom Research, appears twice annually, in May and November, and welcomes manuscripts on any aspect of diatom biology.
In addition to normally structured papers (see below), Short Notes and reviews of recent literature are published which need not contain all the sections required for "normal" papers; we see these as being necessary to record information which is of interest but which cannot be followed up in detail.
Enquiries and orders to: Biopress Limited, 17 Wimbledon Road, Bristol BS6 7YA, UK The International Society for Diatom Research is a registered charity.
www.isdr.org /research-e.html   (842 words)

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