A NOTE ON SOME SUFFOLK ALGAE

On 20^th March 2005 a sample of algae was taken at Redgate Hard, Ipswich near the River Orwell at TM 173403 by Elaine Monahan.

Present in the mixture were Enteromorpha intestinalis (Linnaeus) Link (1820), Blidingia minima (Nägeli ex Kützing) Kylin (1947), Blidingia marginata (J.Agardh) P.Dangeard (1958), Rhizoclonium tortuosum (Dillwyn) Kützing (1845).

At the time E. intestinalis was given its Latin name, most households would prepare animals, birds or fish for eating either as meat or sausages. People would have been quite familiar with the look and feel of what was inside. For that is what the name means: “looks like insides” (Enteromorpha) and again “insides” (intestinalis). It would be simpler to call it “Guts guts” or “Bowels bowels”, this last name appropriately similar to the Latin for sausages.

          In its environment the tubes of this alga are soaked by mist, rain or the incoming tide. When wet it feels slippery and slimy like guts, and necessarily so. We may well go for decades without ever being aware of the waves of contractions squeezing food along our intestines. All this movement can only happen because the loops of tube inside us slip and slide against each other. You can easily get an idea of the work involved by eating some beetroot, or equally effective if less colourful, some medicinal charcoal. 24 hours later it should be coming away from the lower end of your gut, having been squeezed, pushed and pummelled along eight metres of snugly coiled piping without your being aware at all.

          The Enteromorpha algae have similar needs for lubrication. When their tubes are subject to violent stormy weather, despite their slipperiness they can suffer so much wear that little more than their holdfast, attaching them to the underlying rock, remains. Since we don’t all live at the seaside, landlubbers will commonly see a similar effect of friction on soft-sided, or more correctly, curtain-sided lorries. The curtain sides are held tightly down by a row of buckles and straps. When the lorry is moving the straps, like the tubes of Enteromorpha, are free to flap and they wipe clean the swathe of curtain within their reach, the brighter colour clear to see against the grimier remainder. Now that lorry cabs are more streamlined the outside rear-view mirrors are less subject to road spray than formerly but some drivers still tie a strip of cloth above or below these mirrors and rely on the friction from the flapping to flay their mirrors clean.

         The E. intestinalis itself lives on the upper seashore and is very common around our coasts, as can be seen in the recently published Atlas of Seaweeds. It is a thin-walled tube, maybe 30 cm long. The walls are only one cell thick, which are on average quite small being 20 μm in diameter and are arranged in no particular order. This chaotic characteristic is useful as both here and further upstream in freshwater its look-a-like relative E. flexuosa, often labelled as E. intestinalis in collections, has on re-examination been found to have regularly arranged cells.

         Both Blidingias live higher up the shore and can withstand long periods of dryness, The common B. minima is similar to its larger cousin E. intestinalis, except that it is much smaller in all respects even down to its cells which are only about 6 μm on average. B. marginata again resembles E. intestinalis but is also for the miniaturists amongst you, being not only more petite but neater, has its tiny cells often arranged in tidy rows.

          Rhizoclonium tortuosum is green and common along the high shore around the UK.  Instead of being a tube it is a long line of cyAugust 17, 2005 7:33m long. It is a filament with the cells fitted neatly end to end except for the occasional cell that has branched and extended sideways to form the beginning of a rootlet of only a few cells length. The cells that make up the rootlet loose their chloroplasts (the green bits) and appear empty but in reality the cells will be full of sap.

         There were a few very short strands of a small green filamentous species that was not really typical of either Rosenvingiella or Ulothrix, which it most resembled. I must confess I was unable to identify it along with a few strands of blue-green algae that were also present.  

Hardy, F.G. & Guiry M.D. 2003. A Check-list and Atlas of the Seaweeds of Britain and Ireland. The British Phycological Society.

My thanks must go to Roger Berry for his advice on lorries and to Elaine Monahan for the seaweed sample.