Minute tube worms, lack of rain and Anglesey Abbey

The water level in my small marine tank had reached a level several millimetres below the set marker, so an artificial rain of fresh water was called for. The water was added whilst vigorously stirring the tank, mimicking rain and tide, until the level was about 2mm above the set level marker.

Yesterday's stirring had led to an accumulation of sand towards the front of the tank, today's activity again lowered this by half a centimetre or more and exposed some fine, 1 to 2mm wide delicate tubes made of fine sand and silt. Observation this evening found two thread like tentacles emanating from the top of the tube and waving around. So far a precise identification of the occupant has eluded me.

Two mussels, one approximately 4 to 5 mm long , had affixed themselves firmly to the front pane of the tank with fine securing threads (byssus) that permitted them to withstand the turbulance of my artificial tide. As usual, I also removed the 5cm long shell with the two barnacles and gave them a scrub with an old toothbrush, to scour off any growth on their surface. The barnacles can be seen feeding several times during the day.

During the week, a small tall spired shelled snail, again only 4 to 5 mm long, can occasionally be seen on the tank sides. At night, with lateral torch illumination, you can see numerous sub-millimetre long copepods or similar crustaceans swimming towards the light and faint roundworms of a similar size.

With regards to rain, we have had considerably less rain this month than the average and Mrs T directed me to an excellent document from the Environment Agency, the monthly Water Situation Report. The one for April can be found here http://www.environment-agency.gov.uk/static/documents/Research/WSR_April_2011.pdf. The agency brings together information on rainfall, soil moisture deficit, river flows, groundwater levels and reservoir stocks. The simple maps of England, showing the situation in the regions through colour coding, were most striking. Red for very low rainfall (less than 30% monthly average) covered almost 95% of the country for April. This appeared to be a trend of less than usual rainfall for the past quarter.

This afternoon, on Mrs T's suggestion, we made an enjoyable excursion to Anglesey Abbey in the glorious sunshine. Taking cameras, we spent a couple of hours of wandering around the gardens, photographing the flowers. My particular efforts were directed to recording the structure of flower and vegetation as examples to be used for painting practice.