by Roy Winsby
Manchester Microscopical and Natural History Society - Extracts from the Societys Newsletter No. 39, January 1998
(Images by Dave Walker from
Type slide of foraminifera prepared by Brian Darnton. Each square is 1.2mm across.
Editor's note: this is a long article which you may wish to save and read off-line
Two popular subjects for amateur microscopists are diatoms and foraminifera. This article is about foraminifera, or forams, as they are often called.
As is generally known, forams are like an amoeba in a tiny shell, they being amongst the smallest of the protozoa. They are almost exclusively marine and live in immense numbers in the sea, feeding on diatoms and other minute size particles. They have short lives and when they die the tests, their shells, fall to the bottom of the sea in what has been described, because of their immense numbers, as like never ending rain.
The tests are washed up in quantity on the beach, so the books say, but there is always an "if" and here the "if" means if you are lucky in finding them or, as I should say, finding the right beach. Generally the first place to look is amongst that whitish line of beach debris known as the strand line left by the receding tide. So often even this strand line is disappointing with not many (if in fact any at all) forams being found.
The most common mineral found in most beach sands is quartz, a very hard mineral, glass like, usually colourless but sometimes pink or light brown. Of course there are normally various other minerals in sand, and depending on where you find the sand the greater will be the difference in the minerals found. Sand from my nearby UK Lancashire and Cumbria coasts appears to be practically all quartz and no forams. I have sand from all over the world and searching for forams is most disappointing. Sand from Rhodes is full of multi-coloured grains, red, black and brown, very nice to look at under the stereo microscope but no forams. Some of the beaches around Cyprus have a good sprinkling of forams, provided you avoid the ports where the sand is stained dark from the oil discharged from the ships.
Unfortunately, good foraminifera sand is not easy to find for most of us, particularly if we live inland, but even if you live near the sea you are not necessarily any more fortunate. In my working life people at the office, knowing my interest, used to bring back samples of sand from their holidays for me. Eager to please they asked "How was it, is it what you wanted, can I see it under your microscope?" So often it was not of interest and it went on the flowerbed in the garden. They had tried and of course I had to be nice and say it was good. They were not to know that only one beach in thirty or so yields any forams, so I showed them some sand from Cyprus with a good sprinkling of forams. "Isnt it good, I will bring you some more from the next place I go to on holiday". I felt like saying "Do not bother, in all probability it will not be any better and it will go on the garden flowerbed like the last lot" but what can you do when people have tried to be kind. No doubt many of you have had this same experience.
Even when you do find some forams, they are of calcareous material and whilst robust in themselves they are not as hard as the quartz grains, the sharp edges of which act like tiny scalpels and grind them down, which is one of the reasons you can find many incomplete specimens.
If you collect foraminifera sand from around the world as I have done, and obtain lots of samples, you may occasionally come across forams which I can only describe as looking chalky and rough, and you will wonder what is wrong with them. I wondered myself until I read the article "Sands of the World" by Dr. W. N. Mack in the August 1996 issue of "Scientific American". Dr. Mack attributes this condition to the calcareous decay of the forams.
Amongst the many common minerals and other items found in beach sand are quartz as already mentioned, mica, coral, colourful garnet, sponge spicules, sea urchin spines, heads of cryolites (like miniature white pin wheels), sometimes small pieces of coal and other rocks, magnetite, calcite and bits of broken shells. Magnetite is magnetic, in small black grains and you can tell if it is present by passing a magnet over the sand. Calcite is white and bubbles when a few drops of vinegar are added. And of course there are the nicely formed icicle type sponge spicules. Sponges are a strange form of life, one of the few forms of animal life which are without enemies, other than disease. Practically all creatures from the size of diatoms upwards, human or otherwise, need a skeleton or a shell, or lacking these some other form of support. Sponges are amongst the other form, having glass like spicules usually of calcium carbonate or silica. Even jellyfish have tough fibres to keep them rigid.
Sponges are freshwater and marine. Freshwater sponges do not have any commercial value and the only marine sponges which do have any commercial value are the bath sponges found in the tropics because these do not have the sharp spicules, which would of course render them useless as bath sponges. Bath sponges, which are brought up from the sea bed by divers, are beaten and washed to remove any hard debris so that the only part remaining is spongin, the natural bath sponge (as distinct from the now common cheaper manufactured synthetic sponges).
Sponge spicules vary considerably in shape; in freshwater sponges they are usually straight, pointed at each end, sometimes pointed at only one end. Spicules in seawater sponges are found as three, four or five rayed, or like an anchor, cross, star, etc. embedded in the outer tissue of the sponge to give it the firmness needed to withstand the battering from the sea. The spicules are numerous and link to give strength, likened to a box of dressing pins. In some sponges spicules of the different types are found, linked together.
So, how do you find forams in beach sand when they are so elusive? I am not aware if one can buy packs of foraminifera sand from any UK supply house. If you can please let me know and I will publish the information. You can look for forminifera sand on the beach when you go on holiday to a coastal resort but in most cases you will be unlucky. I have tried often enough and know only too well how difficult it is, you come away disappointed. After that your next best bet is a friend who may have some to spare.
with the copies of this Newsletter sent to existing
members and others currently on our mailing list, we are
pleased to be able to come to your rescue. A sample of
very rich foraminifera sand is enclosed. DOGS
BAY SAND, CONNEMARA, Co. GALWAY, EIRE. <Editor's note:
refers to the sample enclosed with the original
Dogs Bay, Connemara, on the west coast of Eire, is in a region of supreme beauty dominated by the mountain range known as the Twelve Bens. I said in the foregoing article that the first place to look for forams is the strand line, but at Dogs Bay, however, the pure white sand on the beach is composed almost entirely of pure white tests of forams, there is an almost total absence of the usual debris found in beach sand from other areas.
Image shows a selection of
In July 1997 member Gerry Cheetham went on holiday to Eire, touring by car, and he brought back a sufficient quantity of Dogs Bay sand to enable me to send a sample with the Societys Newsletter for members to look at under the microscope, preferably a stereo microscope at around x8 to x16 magnification with top lighting, increasing to x24 or perhaps even x30 depending on your microscope. You can go even higher with the magnification but then you then have the problem of depth of focus if you are looking at a number of forams, perhaps not quite so bad for examination of individual forams and you are prepared to adjust for the depth of focus.
Gerry sent me a postcard of Dogs Bay showing the large sweep of the bay, the large expanse of sand being pure white. The sample of sand enclosed is as collected straight off the beach by Gerry, unsorted, but washed by me to remove the salt. The quantity Gerry brought me filled over two plastic bucketsful and it took me all of three Sundays to wash this lot, a trowelful at a time in six washings of tap water. After this, it takes a lot of drying. I laid it out on boards on the lawn to partly dry in the September sun, then a day on a few sheets of newspaper to take out a lot of the remaining dampness, then a further day on sheets of fresh newspaper before I transferred it to saucers, petri dishes and the such like to dry on the window ledges. I had sand all over the house.
The Societys transactions for 1900 contained on page 71 a 3½ page article on Narin Foraminiferous sand which was read to the members of the Society at their meeting in Manchester on the 6th February 1900, and I am setting out below the first page for your interest and information.
'NARIN FORAMINIFEROUS STRAND Co. DONEGAL, WEST COAST, WITH SOME NOTES ON DOGS BAY.'
'Dogs Bay, Galway, Eire, has long been known for the immense quantities of Foraminifera it yields, the surface of the strand at times being entirely composed of their tests with, in patches, some tiny mollusca. So plentiful are they that the blown sand-hills there are practically Foraminifera. It is a sight never to be forgotten by the microscopist, and especially one who has perhaps only obtained small quantities by exchange, or collected them laboriously on some silicious strand, to see on a hot breezy day, when the tide is out, this fine foraminiferous surface of the strand, moving steadily inland, till it covers both the remnants of the grassy sward and old kitchen middens with a white fall like driven snow, filling up hollows and cattle tracks level with the general surface.
In July, 1895, on such a day, the forams were blowing up from the strand rapidly, and R. Standen and Ed Collier, of Manchester, watched R.Welch, of Belfast, put his foot and leg into a hollow filled with such material as white as snow till he sunk almost to the knee.
In April, after the winter storms, the surface while it still contains a larger proportion of Foraminifera than any other British or Irish strand, does not approach the condition of July or August, when the surface, especially after a spell of calm weather, has the material thick, unmixed and tests largely unbroken. At this time any part of the surface will float like thick cream, and that part which sinks may be dried and refloated several times. It is advisable indeed to do so, to get rid of the salt, which in the course of time by attracting moisture, and thus growing mildew or other fungus growth more or less damages the stored material.'
The Dogs Bay sand is very rich in its number of species but there are not many books on identifying forams suitable for the amateur. "The Microscope Made Easy" by A. Lawrence Wells, 1962 and later reprints, has a fine plate of 20 forams with names on page 208. This book is now out of print but it is often seen offered in Savona Books catalogue at around £8 plus carriage.
I also have a copy of "An Atlas of British Recent Foraminiferids" by John W. Murray, 1971, 244 pages, Heinemann, ISBN 0 435 62430 X, long out of print but which can be requisitioned through your local library - if you all requisition it there will be a long wait for some of you! A copy was offered in Savona Books catalogue during last year at £28 plus carriage.
Another book is "Foraminifera" by J.R.Haynes, 1981, 433 pages, Macmillan, ISBN 0 333 28681 2, which can also be requisitioned through your local library. This is a heavy book and most of its pages are devoted to text, including some 40 pages of references, so there is plenty of heavy reading matter. It does, however, contain a fair number of black and white illustrations of the main forms of foraminifera and their development, plus 25 pages of scanning electron photomicrographs. A copy of this book is in our MMS library in Manchester, so it is available for borrowing by any of our attending members. We do not have a postal lending service so please do not ask for this book to be posted to you. However, I consider this book to be rather advanced and not for the likes of many of you who, as an amateur like me, have only a sprinkling of knowledge of foraminifera. In fact the book itself, in its Preface, states that it is designed as an advanced text for undergraduate students of palaeontology and for post graduate students reading MSc courses in micropalaeontology or embarking on research into foraminifera. Many of these people seek employment in the oil research industry.
Then there is the exceedingly well known book, "Foraminifera, their Classification and Economic Use" by G.A.Cushman, Harvard University Press (USA), 1940, to the fourth edition in 1980, ISBN 0 674 30801 8. In the PMS Balsam Post No. 37, October 1997, Brian Darnton mentions that this work is in two volumes, one of text and the other with illustrations, these illustrations being of incredible clarity, white on black, in 55 plates. I have often looked up in Savona Books catalogue for Cushmans two volume publication but I never see it listed. Perhaps it may be some day, and perhaps again no doubt you may get your order in before me.
The above mentioned four books are out of print. Arent the books we would like always out of print these days. However, Brian tells me that there is one book "Foraminifera of the Challanger" by Brady with beautiful paintings of foraminifera, and a good one at that, currently available. I understand that the illustrations in the book are from three sides (top, base and side) and are optical rather than SEM photographs. So we are in luck or are we waiting until you hear the price: it is £185. But do not be horrified at this price, because from what I hear it is worth it.
Originally this work by Brady was in two giant volumes, but in the currently available slimmer £185 edition, obtainable from the bookshop at the Natural History Museum at South Kensington, London, much of the original work has been reproduced, as well as updating the scientific names. So you can see, a book on identifying forams is in print and still available, ready for you to buy at a mere £185. Postage will of course be extra, but place your order or get there soon before they sell out! Joking aside, I am told by two knowledgeable sources that this is an excellent work and even at the price it is well worth buying by the serious amateur foraminist interested in the identification and classification of foraminifera, particularly as it is right up to date, the names of the forams having been brought up to date where necessary.
Murrays 1971 "Atlas of British Recent Foraminiferids" is an excellent book, though only 12 pages are devoted to general text, the other pages being plates of scanning electron photomicrographs with full descriptions on the facing pages. However, the SEM photomicro-graphs are not easy to relate to the forams we see through the microscope and I had difficulty in identifying them, so I enlisted the aid of the knowledgeable and ever so helpful Brian Darnton who very kindly helped me considerably in identifying many of the various forams to be found in the Dogs Bay sand. Brian tells me that there are no common English type names of forams. Where numbers are shown in brackets following the undermentioned names they are the relevant pages of the photographs of those forams which appear in Murrays 1971 Atlas, so if you have a copy you can look them up. Brian identified many of the forams, telling me that the ice cream cone types are likely to be some of the various species of Textularia. The dominant single species in the Dogs Bay sand is *Rosalina globularis (135). Significant other species but in more limited quantities are Rosalina bradyi (-), Polystomella crispa (-), Massilina secans (67), *Lagena (several species, 81-89), *Oolina (several species, 93-95), *Fissurina orbignyana (99), *Ammonia beccarii (151), *Elphidium crispum (155), Elphidium gerthi (161), Planorbulina mediterranensis (179), Acervulina inhaerens (181) and Globigerina bulloides (211).
Other species are also present in smaller numbers, including the rams horn foram which is one you will immediately recognise if you find one. You will find bryozoans, shells of minute sea urchins, many of the icicle looking sponge spicules, mostly the three rayed variety from the Purse sponge and an odd one or two of the four rayed spicules from other sponges. The three rayed spicules radiate slightly downwards but with the four rayed variety the fourth ray arises from the centre point in an upwards direction. Often this fourth ray is broken off and only the stub is seen rising up from the centre of the others. You will also find urchin spines of a minute species, as well as short lengths of what look like fine braided cord which can be spines from fine sea urchins or sea mats; sometimes these are found with the joint bit at one end.
Another book is "A Synopsis of British Nearshore Foraminiferids" by John W. Murray. I have a copy of this 68 pages book but it is missing its frontispiece page so unfortunately I do not know its date of publication, though it is obviously later than 1971 since the author refers to his 1971 book. In it he emphasizes that foraminifera can only properly be identified in their dead dry state, their appearance changing markedly when they are immersed in water or even mounted in mounting medium. This book covers 63 species and depicts line drawings of them.
An article "The Collection and Mounting of Recent Foraminifera" by Brian Darnton on pages 14 to 17 of the Quekett Bulletin No. 16 (Winter 1990) includes a grid of 20 line drawings of forams found at Swanage Bay, Dorset. One of the paragraphs above gives names of forams identified by Brian in the Dogs Bay sand and those indicated by an asterisk are included in the drawings in the Quekett Bulletin.
Before I go any further, I wish to record that amongst us amateur microscopists there are two people who I regard as first class in the identification and mounting of foraminifera, Brian Darnton of Dorset and Douglas Richardson of Skipton, and when you see their slides you may well query my use of the term amateur, as they both have a high degree of professionalism.
This Dogs Bay sand is extremely rich in its variety of all sorts of forams and the names of the specimens given in this article as having been found in it is by no means a complete list as there could be other species which because of their smaller numbers have not yet been identified. Do please let me know if you identify any others and I will pass the information on to Brian. I regard him as an expert in foraminifera and described him as such in the first draft of this article but he modestly decried it and asked me to alter it, which I did with reluctance. Actually I had applied the term "expert" to both Brian and Douglas, but in deference to Brian I altered the "expert" to "first class". Brian said it is the oil industry which has the experts.
Forams are very robust and their small size makes us regard them as being more fragile than they really are. I had thought of sending them out in small plastic phials or boxes, requiring heavier stronger envelopes, but the expense of any of these and the packing for the post would have made this uneconomical. I decided I would send them out in plastic self seal packs but I worried about the flimsiness of these and as to how the forams would be crushed under the fingers and thumbs of the postmen delivering the envelopes.
So I did a crushing and treading-on experiment, taking one of the packs of the Dogs Bay sand, and on three occasions I ground it hard between fingers and thumb, then for good measure I trod on it and moved my foot around. Dont worry, your pack is not this one! I expected this crushing and stamping would have ground it all to a powder but when I examined it under the stereo microscope I could hardly believe it. Comparing it to the "uncrushed not stood on" Dogs Bay sand it was not easy to tell the difference and even many of the three rayed icicle type sponge spicules were unbroken. Actually, it is when you consider that people walk over the sand on the beach at Dogs Bay that you can appreciate just how robust these tests of forams are.
Now how to examine the sand. First examine a little of it dry on a watch glass, using top lighting. You have lots in the enclosed pack as a salt-spoonful is more than enough for initial examination. Use too much and you will miss most of the small forams. Take time and examine the sand carefully with a seeker, shifting it to one side in small amounts. It might look fawn in colour in the pack but it shows up practically all pure white or colourless under the microscope.
If a slide is made for transmitted (below the stage) lighting it can be mounted in a resin mountant such as Numount or Eukitt in a ringed slide. It is worthwhile to glue forams destined for strews with a weak film of gum tragacanth onto a slide in order to prevent movement and clustering after mounting, particularly if the slides are ever stored on edge. I said earlier that I have washed the sand to remove the salt, but remember that forams are hollow and contain air, so another worthwhile prerequisite is to leave the dried slide in a xylene bath for an hour or so just before mounting in order to expel the air pockets. During drying, however, it must be remembered to feed the mountant as the xylene solvent is evaporated.
When you have made your resin mounted slide, dont forget to also examine it by both darkground and polarized light as you will be surprised at the result. Not only do these bring out more detail but some of the forams show colours. With crossed polars using below the stage lighting you can go over x40 magnification and not get the same problem of depth of focus.
Or you can make slides for incident (top) lighting by painting the centre of a pre-ringed slide with mat black and when dry cover the black with a thin film of gum tragacanth on which to sprinkle some forams. As this film of gum is so thin it will dry quickly, so breathe on it to soften the gum. For these black bottom slides you can also use LePages or Stevens Office gum thinned with water and because the forams will not be sealed in a resin mountant you can use a slightly thicker film of gum to guard against forams becoming loose in a deep ringed cell slide.
If you do not have any NBS mat black to hand and want something quick, visit the cosmetic stall at your local market and buy a small bottle of mat black nail varnish, usually up to around 50p a bottle. It is not quite as good as NBS mat black as some makes still dry with a slight sheen, but it is easy to apply, it dries quickly and serves the purpose. If however you are making exhibition slides, buy the NBS mat black. You can of course make a "half and half slide", with one half blacked for viewing with top light and the other half left clear for below the stage lighting.
I trust that if you are not already interested in foraminifera then this sample of Dogs Bay sand will start you off. It is about as profuse with forams and as varied with species as you are likely to find in any beach sand, although Brian has told me that there is a site on the Scottish island of Mull, NW corner at Calgary Bay, which is also equally rich in forams. Unfortunately it is not easy for most of us to reach such an outlandish area, but if anyone is going there on holiday or otherwise and would be willing to bring me back a good quantity I will ensure you all receive a sample. The only perhaps better source is obtained by geologists in the oil industry from borings in the seabed, but then how many of us amateurs have a hope of obtaining such quality material. I have a small sample from a deep sea boring from the seabed off the coast of Burma, all beautiful globerina, but this is precious and I am not prepared to part with it, though I exhibit it often enough as one of the specimens on my turntable of forams at exhibitions.
I have collected foraminifera sand for a good few years, samples of which I keep dry in small plastic boxes. Nine of these boxes of different sands on a turntable on my MBS-9 stereo microscope at microscope exhibitions have always created much interest. One of these specimens is of globerina from the Burma deep sea boring, which many of you will have seen. Forams are easy to put in small plastic boxes, labelled as to where they are from, and up to now that has been the extent of my interest. This Dogs Bay sand has, however, created even more interest for me and I hope it creates an interest for you too.
Brian makes excellent slides of foraminifera and in particular is currently able to supply a slide of foraminifera of the British Isles, including some from the Dogs Bay sand, dry mounted on a 16 square white numbered matrix grid on a black base, accompanied by an identification list referring to the types of forams on the slide, at a price of £5 for UK and Europe, $10 for non Europe <Editor's note - shown at the head of this article>. Considering the time involved in preparing the numbered grids, selecting, sorting and mounting the forams, as well as listing them on an identification list, I regard this price to Brian as just about passable for his time, effort, material, protective packing and postage, and to you as prospective purchaser, as very fair. The slides are available from Brian Darnton at Flat No.1, No. 8 Park Road, Swanage, Dorset, BH19 2AD, UK.
by Roy Winsby.
We thank Roy Winsby for submitting and allowing us to reproduce this article. Roy can be contacted via the details on the Web site below.
Visit the Manchester Microscopical and Natural History Society Web site, where the history and activities of the society as well as contacts and membership details are provided.
Read Brian Darnton's illustrated article on collecting and preparing foraminifera from chalk.
The images taken by Dave Walker used a 50mm Nikon SLR lens with extension tubes attached to a Panasonic CL350 video camera. Images captured with a 'Snappy 2.0'.
Published in August 1998 Micscape Magazine.
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