Wednesday, 24 December 2014
After making slides of canada balsam in which the tests are protected by supporting the cover slips by small tabs of various diameters and thicknesses, other problems emerged; When near transparency finally emerges, it becomes evident that the tests need to be far cleaner than for dry mounting, so an extra cleaning stage needs to be introduced. The first effort with hydrogen peroxide might be helping but long term immersion will be needed at the very least.I hope more lucid images will emerge. Please remember to click on the image to make it larger.
Sunday, 6 July 2014
Budding or not?
This is an image of probably Haynesina germanica . Is was an empty test found in a deposition zone in Poole Harbour. Each Summer these tests and those of some others like Elphidium Williamsoni are found on the shores of the Harbour.
I have always assumed that the capsules were the primary chambers of a budding adult but I cant find very good images around the net to confirm this can anyone help . Brian Darnton.
The foram is ot cleaned but mounted in Canada Balsam without pressure .
Wednesday, 4 June 2014
The Foraminifera of the Swanage Shores.
These beautiful
shell like creatures can only be seen with a good hand lens or better still a
simple microscope. Our local species are only a fraction of a millimetre in
diameter.
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What is rarely
appreciated is that they also flourish today as living creatures in the open
sea as part of the plankton and the estuarine areas of river as at Poole. Foraminifera are actually closely related to
the Amoeba of our school text books but they grow a shell like structure called
a test to protect themselves from the many hungry creatures of the seas. There
are no organs and these animals belong to the Protista: the simplest and
earliest of creatures to appear on Earth. The tests are made of various types
of chalk (calcite). Some species seem to be almost transparent, being
constructed of crystalline calcite, but others seem to be paved with porcelain
like chalk but in the river mouths where there is less chalk dissolved in the
water, they are protected by particles of sand or debris bonded onto a covering
of a chitin-like material. These are called arenaceous species. The
Foraminifera are clearly masters of adaptation as well as being climate
indicators. Generally the white tests are noteasy to find because they are very
small but in deposition areas they can be found en masse, usually mixed with
black sea coal from industrial spillage and ship wrecks. This gives these sites
a black and white banding which is easy to spot
(See above Right). In Swanage Bay an
area can be discovered between the Mowlem building and the Public Hard at low
tide. Washing, sieving, drying and floatation in clean, fresh water all help
to improve the sample.
As well as Swanage, Weymouth and
Fleet, there are local deposits within Poole Harbour near the Salt
marshes at Arne and Redhorn Quay where they lie almost unseen, amongst the
small washed up shells. The ornamental tests of these invertebrates are
objects of considerable aesthetic appeal and beauty as well as having a
significant scientific interest. The two illustrations above, clearly show
the difference between the Open Sea British Channel fauna of Swanage Bay and
the estuarine fauna of Poole Harbour below with a proportion of gritty arenaceous
types, which are very ornamental in polarised light.
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