Tuesday 11 June 2013

Red Tide?

How's that for an impressive algal bloom? Do not be alarmed or get upset on our behalf; read on. If like us you have ever constructed ponds and proudly filled them and set them 'running' from new, you will probably have given birth to a few algal blooms in your time but we have to admit this is our first RED one. Algae, you will probably know, come in a variety of flavours from the well known and common 'Green', through Blue-Green and into Brown and then Red, as well as covering the range from very simple single-celled organisms right through to what we all know as 'sea-weed'.

The green variety are generally caused by an increase in the levels of nitrogenous compounds in the water and, as many people know, can be helped and avoided (though we've never done this) by adding barley straw. The bacteria trying to break down the straw find themselves short of nitrogen (in the straw) so they draw it from the water, thus reducing the nitrogen level in the water and starving the algae. Blue-greens are similar but are known for the risk of poisoning the water with a nerve agent called 'anatoxin' as they die and break down, which is never a good idea if cattle are drinking from that water.

Your man the Red Alga is of a different cloth  altogether, being generally marine (i.e. sea water rather than fresh) but also commonly caused by phosphate and phosphorus compounds in the water. You will recall that the very day we completed the pond was the day it stopped raining and the heat wave started so we, despite our misgivings, opted to fill the pond from the mains. 2 factors almost guaranteed to help an algal bloom along are warmth and intense sunlight. We had gin-clear water and a black butyl liner, not a bit of shade or any plants at that stage; the whole acting as a big solar panel.

Also Roscommon Water Board are currently suffering from contamination in the supply with a protozoan called Cryptosporidium which causes diarrhoea and we are under an official 'boil water' notice in parts of the county, and may be using chemicals to try to stop this PLUS we have heard, to help remove the natural peaty brownness of the water. Whatever the causes, our pond warmed up a lot and Bingo! our red algal bloom. This appeared overnight a few days ago, first as a slight red tinge on the bottom sediment, but then, as the water warmed up in the heat wave, causing a haze in the water which stopped us seeing the deepest parts of the pond. It has followed a textbook course, and we have the small flecks of 'scum' you get with red alga, looking like wind blown grass clippings. Admittedly we also have actual grass clippings!

As I said, do not be alarmed. We have not killed the pond. It is not a toxic waste dump you are looking at here; It may look a little shocking and scary in the pictures but it is still very much alive with oxygen getting to all levels. We have undiminished and increasing numbers of boatmen, pond skaters, water beetles and all manner of other whizzers up and down through the depths of the pond, the plants we have started to accumulate are all healthy and alive and the geese are still happy to swim in it and drink from it. The advice is that as soon as the temperature drops, the light levels fall and the rain water starts to dilute the (suspected) phosphates or other treatment chemicals and/or the algae exhaust the supply of what ever caused the bloom, it will fade away again. For that reason we are quite relieved that the heat wave is over and it is raining again. We are certainly not about to reach for any more chemicals to add to the brew to try to 'kill' the algae, or indeed to pump out and re-start. We will keep you posted on the progress of our own private red tide.

On a calmer note, Liz has found a knitting circle in Ballaghaderreen as a way of getting 'off campus' once a week, getting some female company, meeting new friends and honing the knitting skills. Our mini-horse owning friend from down the road, Carolyn tipped Liz off on this one; it turns out that Carolyn is also a keen knitter as well as being a demon sewing machine user, ex-shop-demonstrator and repairer. This also gives Liz a new way of relaxing when book reading and messing on the internet pall and can be done indoors as well as out. She has her own gentle pace and rhythm and , so the ladies of the circle tell her, a good feel for a nice even tension. I am looking forward to a nice new jumper.

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