The Microscopic Virtues of Mud
by Brian Darnton, UK
The Victorian mounters knew where to find specimens worthy of their skills. In particular Edward Hawkyard left us an incredible laid slide of Foraminifera from the "Estuarine clay" of Antrim, N. Ireland. On the reverse he named the species, as they were then known.
Last year I deserted my pristine sandy tidemarks of the Mediterranean Sea for a wallow in the mud in what is left reasonably natural in the Dutch delta area of Zeeland, Netherlands. Many of the other coastal areas have been enclosed for various reasons, which include not least the protection of the inhabitants. The WesterSchelde River is still open to the North Sea and has been a major seaway for centuries. It is a gateway to the port of Antwerp in Belgium. A new tunnel has been dug under the Schelde. It's about 6 miles long and it begins near Terneuzen on the south bank, and heads northward. It's scarcely on the maps yet! It has entirely taken the place of the two ferry boat services over the river. Having collected diatoms in the estuary many years ago, lower down at Slijkplaat and Hoofdplaat, I have long since recognised it as a very fruitful place for general microscopy! In the field of diatoms, the splendid centrics and the fine Triceratium favus first noted by van Heurk in his Treatise and other works are familiar to most of us. This year's sample, beautifully illustrated in a related article by Christina Brodie comes from the bay next to the main harbour in front of the Raadhuis at Terneuzen. It looked pretty foul but was covered with a slimy green bloom of Pleurosigma angulatum, a sign that the water is less saline in this up-river situation. This is the famous test diatom for medium to higher powers.
The species of Foraminifera, after filtering in a 100 micron filter and cleaning in hydrogen peroxide for a couple of days are typically estuarine, being dominated by Ammonia beccarii and Protelphidium germanicum, various species of Elphidium, Cibicides lobatulus and Brizalina variablis were also evident. The remaining species were small numbers of the fauna of the North Sea and some fossil species of Nummulites washed out from local tertiary beds. An unexpected find was several damaged species more common to warmer waters, which have presumably arrived on the hulls of boats from exotic climes. The river is full of shifting sandbanks and mudflats. "Bottoming" or scraping on the sand is not uncommon at low tide. Most of the southern edge of this estuarine basin is accessible with safety by stone causeways that extend from the upper shore down into the water. The mud itself, is dangerously deceptive on the Schelde shores. The coastal road runs parallel to the river. The new route through this corner of Zeeland, Netherlands, is very much on the way to northern Europe from the Channel ports and one day the opportunity for collection may present itself. Low waters during spring tides are the best periods for visits. These can be looked up in yachting journals in the public library system.
Feedback to the author, Brian Darnton is welcomed.
Micscape link: Image Gallery: Foraminifera from the Westerschelde, The Netherlands by Christina Brodie.
© Microscopy-UK or their contributors.Published in the February 2004 edition of Micscape Magazine.
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