Diatoms are most abundant in cold latitudes, having a general preference for cold water.
The characteristic brown colour of diatoms is due to the presence of chromatophores embedded in the lining layer of protoplasm.
When the diatoms have settled in the bottom of the jar, the supernatant fluid is carefully removed by a syringe or some similar instrument, so that the sediment be not disturbed.
Many diatoms possess thickenings of the cell-wall, visible in the valve view, in the centre of the valve and at each extremity.
Most of these diatomaceous earths are associated with rocks of Tertiary formations, although it is generally regarded that the earliest appearance of diatoms is in the Upper Cretaceous (chalk).
The former includes all those diatoms which in the valve view possess a radial symmetry around a central point, and which are destitute of a raphe (or a pseudoraphe).
There is little doubt that the movements are connected with the raphe, and in some diatoms there is much evidence to prove that they are due to an exudation of mucilage.
Diatoms are unicellular plants distinguished from kindred forms by the fact of having their soft vegetative part covered by a siliceous case.
These diatoms mostly consist of three or four well-known species.
A tow-net is filled with diatoms in a very short space of time, showing that the floating plant life is many times richer than that of temperate or tropic seas.
Feeding on these diatoms are countless thousands of small shrimps (Euphausia); they can be seen swimming at the edge of every floe and washing about on the overturned pieces.
These diatoms are, to me at least, the most perplexing things in the universe.
It may be he will still, with the utmost nonchalance, be pushing out his pseudopodia, and ingesting diatoms when the fretful transitory life of humanity has passed altogether from the earth.
Cases ofDiatoms in the Richmond "Infusorial earth;" highly magnified.
The process of conjugation in Desmids andDiatoms consists in the union of the endochrome of two individuals, each of which in these families is composed of a single cell.
Large groups of the simpler plants, as you may observe in the diatoms from any stagnant pool, are no less actively locomotive than the minute creatures classed as animals seen along with them.
Diatoms to-day exist in great numbers, both in the cold water of the polar regions and in the heat of hot springs.
In one way thediatoms differ from ordinary fossils.
Clark finds that with returning daylight the diatoms are again appearing.
The diatoms cannot multiply without light, and the ice formed since February can be distinguished in the pressure-ridges by its clear blue colour.
The diatoms have each one a tiny shell or shield, not made of lime like the rhizopod-shells, but of flint.
This goes on very rapidly, and in this plant each new cell separates as it is formed, and the free diatoms move about quite actively in the water.
I have, however, employed the above method and have mounted thousands of slides of selected diatoms successfully.
It is customary, especially among writers who are familiar with other classes of plants, to decry any classification of diatoms according to the markings of their siliceous envelopes.
More or less motion is observed in various kinds of free cells, but the movement of diatoms is not evident in those without either a raphe or a keel upon which and apparently by which the phenomena are produced.
Allow the material to settle for half an hour or longer, according to the amount of diatoms and their size.
Attempts have been made to find material there and while there is an earth containing Miocene diatoms at Petersburg, it does not exactly correspond to the material sent to Ehrenberg by Bailey, who was in doubt as to the locality.
At certain times, when the river is low, the influx of tide water is sufficient to produce an abundance of brackish water diatoms at Greenwich Point.
The sand will cling to the glass, while the greater portion of the diatoms will run off.
On very cold days the glass thread sometimes becomes electrified and the diatoms will not stick; on sultry days in August in our locality the diatoms will stick too closely.
If the stage is supplied with a vernier, the diatoms can be located rapidly and recorded for future reference.
Such accumulations of diatoms are made both in fresh waters and salt, and in those of the ocean at all depths.
In southern California at least, certain of the oils have quite certainly been derived from the very tiny oily plants called diatoms which fill many of the strata.
The Diatoms are so called from their faculty of multiplying themselves indefinitely by splitting into two; and so rapidly is this process performed, that in a month a single diatom may produce a thousand millions.
The peculiar spores of diatoms (called auxospores) increase in size, and at length acquire a siliceous coating, thus becoming new diatoms of full size.
Defn: A genus of diatoms of elongated elliptical shape, but having the sides slightly curved in the form of a letter S.
The Diatoms are still more common, and we see before us in our water-drop some of their simplest representatives in the form of minute boats made of silica (flint) and moved by means still in dispute.
The next eighteen thousand feet of strata are easily identified as Lower Silurian, by the Diatomswhich occur imbedded in them, and these formations include some of the largest deposits of limestone known.
Diatoms of antarctic sea ice as agents of primary production.
It is a collection of artificial ponds, the floors of which are covered with algae, which harbor vast numbers of diatoms and other microscopic organisms on which the oysters feed.
Associated with diatoms, in fresh water, are desmids, which are green in color and resemble the diatoms except in having a cartilaginous instead of a silicious covering.
It feeds partly on diatoms and other small algae, which it cuts from the rocks with its sharp teeth.
Fossil diatoms are ground and used for polishing-powders.
The indigestible constituents (siliceous shells of Diatoms and Tintinnoidea, calcareous shells of small Monothalamia and Polythalamia, &c.
Certain groups, like the Diatoms and Characeæ, are puzzles to the botanist, and at present it is impossible to give them more than a provisional place in the system.
It was evident that these accumulations of diatoms and alga remained floating exactly at the depth where the upper stratum of fresh water rests on the sea-water.
I am now busied with the diatoms and algæ of all kinds that grow on the ice in the uppermost fresh stratum of the sea.
The water on the surface was entirely fresh, and the masses of diatoms sank in it, but floated on reaching the salt-water below.
Went on excursion with Blessing in the forenoon to collect specimens of the brown snow and ice, and gather seaweed and diatoms in the water.
A genus of diatoms of elongated elliptical shape, but having the sides slightly curved in the form of a letter S.
This was found to consist entirely of Diatoms of the same species as those found at the bottom.
It is somewhat singular that Diatoms did not appear to be in such large numbers on the surface over the Diatom ooze as they were a little further north.
A great variety of forms are found, both diatoms and desmids, many still undescribed, inviting the young microscopist to study and name them.
One of the most common diatoms in Cochituate water is the Stephanodiscus Niagarae.
Naturalists formerly placed both diatoms and desmids in the animal kingdom, but now all agree that the desmids are plants, while some few still maintain that the diatoms are animals.
The diatomsoften grow in long ribbon-like masses (fig.
The diatoms are found everywhere in both fresh and salt water, but the desmids live only in fresh water.
The most beautiful of the small algae or water plants are the Diatomaceae and the Desmidiaceae, sometimes called for brevity diatoms and desmids.
The desmids resemble the diatoms in the geometrical character of their forms, but they have no shell of silex, and are therefore easily destroyed.
In this way beds of shells of diatoms are sometimes formed of considerable thickness.
Somewhat similar in habit to the brown Diatoms are the green Desmids, but, whereas, the former also occur in the sea, the latter are all confined to fresh water.
In colour, Diatoms are usually brown or brownish, although they contain chlorophyll, the green colouring matter of higher plants.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "diatoms" in a variety of sentences. We hope that you will now be able to make sentences using this word.
