scholarly journals On some Factors Limiting the Habitat of Arenicola marina

1929 ◽  
Vol 16 (1) ◽  
pp. 109-116 ◽  
Author(s):  
D. M. Reid
Keyword(s):  
Calcium Carbonate ◽  
Ferric Oxide ◽  
Sea Water ◽  
Amorphous State ◽  
Magnesium Carbonate ◽  
Arenicola Marina ◽  
Short Time ◽  
Clay Kaolin

SUMMARYIn the foregoing work it was found that: Arenicola marina was repelled and could not burrow in sand containing 20% of ferric oxide in the amorphous state.That 0·021% ferric oxide in suspension in sea-water was lethal owing to its forming with the mucus of the organism an envelope which prevented contact with the surrounding air-carrying water.That calcium carbonate, magnesium carbonate, Stourbridge clay, kaolin, and kieselguhr had the same effect as the ferric oxide in suspension.That although able to live for a short time in water of salinity 3·10%‰, Arenicola marina tended to become so turgid in water of 14·32%‰ as to be unable to burrow.

scholarly journals The suspended matter of sea water

1950 ◽  
Vol 29 (1) ◽  
pp. 139-143 ◽  
Author(s):  
F. A. J. Armstrong ◽  
W. R. G. Atkins
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Ferric Oxide ◽  
Suspended Matter ◽  
Water Mass ◽  
Sea Water ◽  
Dry Weight ◽  
Insoluble Organic Matter ◽  
Silica Alumina ◽  
Silica Alumina Ratio

Sea water collected at Station E1, surface, between June 1948, and November 1949, contained suspended matter from 2·77 to 0·45 g./m.3 (or parts per million) dried and ignited. A few determinations of insoluble organic matter gave 1·77 to 1·15 parts per million dry weight at 100° C. The ignited residue contained from 55 to 17% silica, 28 to 3 of ferric oxide, 20 to under 1 of alumina and 70 (or excluding one high value 29) to 9 calcium carbonate. There was nothing in the records for temperature or salinity to suggest that the water mass had changed during the period of sampling.The analyses reveal an unsuspectedly large amount of iron, compared with that found in solution. The ignited residue is rich in silicate, judging from the silica alumina ratio, but it is quite doubtful whether the additional supply of silicate available for diatoms is at all adequate to balance their requirements calculated on a phosphate utilization basis. It seems more probable that a considerable amount of the phosphate is available for non-siliceous phytoplankton.

scholarly journals The Effects of Magnetic Nanoparticles Incorporated in Polyelectrolyte Capsules

2017 ◽  
Vol 54 (4) ◽  
pp. 630-634
Author(s):  
Carmen Stavarache ◽  
Mircea Vinatoru ◽  
Timothy Mason ◽  
Larysa Paniwnyk
Keyword(s):  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Calcium Carbonate ◽  
Ferric Oxide ◽  
Iron Content ◽  
Single Layer ◽  
Oxide Nanoparticles ◽  
Polyelectrolyte Multilayer ◽  
The Core ◽  
Calcium Carbonate Template

Polyelectrolyte multilayer capsules are synthesized comprising of 12 total layers each containing a single layer of iron oxide nanoparticles in shells 4, 6, 8 or 10. A protein-labelled dye is embedded in the calcium carbonate template core as a model for the encapsulation of a drug. The core is dissolved after 6 layers are formed. Two types of magnetic nanoparticles are incorporated into various capsule shells: ferric oxide (Fe2O3, 50 nm) and iron oxide (Fe3O4, 15 nm), a 1:1 (vol.) mixture of the two types of nanoparticles suspensions is also used. Nanoparticle inclusion reduces the capsule sizes in all cases with the order of effect Fe3O4 [ Fe2O3 [ Fe2O3/Fe3O4 mixture. When Fe3O4 or a Fe2O3/Fe3O4 mixture is incorporated in layer 6 the reduction in size of the final capsules is less than expected. The number of surviving capsules containing nanoparticles are lower than control regardless of which of the nanoparticles is used but here the effect of Fe3O4 or a mixture of the two types of nanoparticles incorporated in layer 6 was slightly out of step. The amount of iron incorporated is almost the same regardless of which shell the nanoparticles were incorporated but the iron content using 50 nm nanoparticles is generally slightly higher than that obtained with 15 nm nanoparticles.

Studies of the Egg of Bacillus libanicus (Orthoptera, Phasmidae)

1950 ◽  
Vol s3-91 (14) ◽  
pp. 195-203
Author(s):  
A. MOSCONA
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Embryonic Development ◽  
Moisture Content ◽  
Mineral Content ◽  
Calcium Deficiency ◽  
Egg Shells ◽  
Egg Shell ◽  
Short Time ◽  
Initial Mineral

1. Weight, moisture content, and mineral content of freshly laid and of fully developed eggs of Bacillus libanicus (Uv.) were studied. During development of the embryo the egg-shell loses 19 per cent, of its initial mineral content, while the weight of mineral materials in the embryo increases correspondingly. 2. These changes can be explained only as resulting from transfer of minerals from the shell to the embryo. The mineral materials are derived from the calcium carbonate layer of the shell, which, owing to this loss, becomes thinner during embryonic development. 3. It is suggested that the mechanism of this transfer is based on the production of bicarbonate by the reaction of water and carbon dioxide, given off by the embryo, with the calcium carbonate of the shell. 4. Experimental calcium deficiency in the egg-shells results in a marked lowering of the viability of the embryos; although embryogenesis may sometimes proceed till the hatching stage, the few emerging nymphs survive only for a short time. 5. The possible occurrence of mineral transfer in other phasmid eggs is indicated.

Ecotoxicity of contaminated sediments, a matter of bioavailability

1998 ◽  
Vol 37 (6-7) ◽  
pp. 225-231 ◽  
Author(s):  
N. H. B. M. Kaag ◽  
E. M. Foekema ◽  
M. C. Th. Scholten
Keyword(s):  
Dreissena Polymorpha ◽  
Sea Water ◽  
Feeding Habits ◽  
Macoma Balthica ◽  
Contaminated Sediments ◽  
Suspension Feeding ◽  
Simple Relationship ◽  
Filter Feeder ◽  
Arenicola Marina ◽  
The Baltic

Marine and freshwater mesocosm-scale experiments with contaminated sediments have shown that there is a direct relationship between the accumulated contaminant levels and the feeding habits of the organisms used. The highest levels of PAHs and PCBs were found in the sediment feeding lugworm Arenicola marina and in Tubifex worms. The levels of contaminants in the suspension feeding mussels Mytilus edulis and the zebra mussels, Dreissena polymorpha, were not influenced by the contaminant content of the sediments, but were related instead to the level of contaminants in the sea water above. Intermediate levels were found in the baltic tellin, Macoma balthica, which is a filter feeder as well as a deposit feeder, depending on the availability of food. These results show that there is no simple relationship between contaminant concentration in the sediments and bioavailability. Higher levels of contaminants do not necessarily lead to higher levels of these contaminants in Arenicola, due to differences in the sediment structure and the ageing of the contamination. On the other hand, toxic effects are related to the internal concentrations of certain chemicals. The internal concentrations observed in Arenicola may provide a good estimation of the true bioavailability of sedimentary contaminants and can also be used as an indicator for potential environmental effects.

On the Cause and Nature of the Chemical Changes occurring in Oceanic Deposits

1897 ◽  
Vol 21 ◽  
pp. 25-34
Author(s):  
W. N. Hartley
Keyword(s):  
Special Reference ◽  
Ammonium Sulphate ◽  
Royal Society ◽  
Sea Water ◽  
Magnesium Carbonate ◽  
Chemical Examination ◽  
Chemical Changes ◽  
Sulphuretted Hydrogen

In Nature of January 24, 1895, appears an abstract of a paper read before the Royal Society of Edinburgh on March 7, 1892, by Dr John Murray and Mr Robert Irvine, and published in the Transactions of the Society, vol. xxxvii. part 2, No. 23, entitled “Chemical Changes between Sea-water and Oceanic Deposits.”This is an account of a chemical examination of the sea-water salts in the water adhering to or retained in mud, with special reference to the formation of the deposit known as “Blue Mud.”Dittmar's analysis of sea-water is quoted and compared with an analysis of mud-water. The chief points of difference between the two is the occurrence in mud-water salts of 0·206 per cent. of ammonium sulphate, 0·729 per cent. of magnesium carbonate, and 0·18 per cent. of manganous carbonate; also that the total salts are low in proportion to the chlorine they contain.The occurrence of ammonium sulphate in this mud, and also of manganous carbonate, are facts of much interest; but there are some equations given to explain the chemical changes which the mud undergoes which are not strictly in accordance with facts. There are three points which I would desire to draw attention to: first, the reduction of the sulphates; second, the oxidation of sulphuretted hydrogen; and third, the formation of manganous carbonate.The equations are written without reference to the part played by water in the chemical changes involved, but it may have been thought that the accuracy sacrificed was compensated by the simpler form of the equations.

scholarly journals IV. On the composition of sea-water in the different parts of the ocean

1865 ◽  
Vol 155 ◽  
pp. 203-262 ◽  
Keyword(s):  
Sea Water ◽  
Metamorphic Rocks ◽  
Chemical Examination ◽  
Different Depths ◽  
The Mediterranean ◽  
Short Time ◽  
Different Parts

In the year 1843 a friend of mine, Mr. Ennis of Falmouth, sent me some bottles of seawater from the Mediterranean, which I subjected to a chemical examination, a work which induced me to collect what other chemists had determined about the constitution of the water of the great Ocean. This labour convinced me that our knowledge of, the composition of sea-water was very deficient, and that we knew very little about the differences in composition which occur in different parts of the sea. I entered into this labour more as a geologist than as a chemist, wishing, principally to find facts which could serve as a basis for the explanation of those effects, that have taken place at the formation of those voluminous beds which once were deposited at the bottom of the ocean. I thought that it was absolutely necessary to know with precision the composition of the water of the present ocean, in order to form an opinion about the action of that ocean from which the mountain limestone, the oolite and the chalk with its flint have been deposited, in the same way as it has been of the most material influence upon science to know the chemical actions of the present volcanos, in order to determine the causes which have acted in forming the older plutonic and many of the metamorphic rocks. Thus I determined to undertake a series of investigations upon the composition of the water of the ocean, and of its large inlets and bays, and ever since that time I have assiduously collected and analyzed water from the different parts of the sea. It is evident that it was impossible to collect this material in a short time, and without the assistance of many friends of science, and I most gratefully acknowledge how much I am indebted to many distinguished officers of the Danish and British Navy, as well as to many private men, who were all willing to undertake the trouble carefully to collect samples of sea-water from different parts of the ocean, both from the surface and from different depths. I shall afterwards, when giving the particular analyses, find an opportunity to mention the name of each of those to whom I am indebted for my material.

scholarly journals On the Amount of Phosphoric Acid in the Sea-Water off Plymouth Sound. II

1917 ◽  
Vol 11 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Donald J. Matthews.
Keyword(s):  
Seasonal Variation ◽  
Phosphoric Acid ◽  
Sea Water ◽  
Soluble Compound ◽  
Short Time

The amount of phosphoric acid in sea-water off Plymouth was at a maximum of 0.06 mg. per litre of P2O5 at the end of December, 1915, after which it fell irregularly to a minimum of less than 0.01 mg., which extended from the last week of April to the latter part of May; it then increased again and in January, 1917, reached the same value as the average for the first part of the month in the previous year.This seasonal variation is probably to be attributed to the removal of the phosphates from solution, at first by the fixed algæ, and later in the spring by the diatoms and for a short time by Phcœcyslis. There is also present in sea-water taken near Plymouth another soluble compound of phosphorus which can be converted into phosphoric acid by oxidising agents.

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