Saturday, January 06, 2007

Scope For Growth


Its late and I can't sleep because wiff gave me her cold and hence I am ridden with snot. So thought I'd lay down an update on the usual cutting edge science.

This is the first week back from the christmas hols and its been a gentle easing into things with the usual 10am starts and 10 cups of tea before anything gets done. The first thing I have to share is that my Scope For Growth [SFG] assay seems to have kicked arse! I set up the feeding rate assay with my ragworms in the week before christmas before going digging on a lovely, clear winters day at Bantham, the Mouth of the River Avon. We found appropriate numbers of wriggly things and carted them back to the lab where I set about making them as comfortable as possible (itsimportant to take care of your worms, otherwise they do not cooperate with later requests). Anyhoo, the worms were allowed to purge their gut contents overnight, as is necessary for SFG, before being weighed and fed the next day. I selected the 24 biggest ones in order to get better data as smaller worms means smaller appetites and smaller amounts of pooh which, in turn, means less accurate measurements, higher standard deviation and arse data. This is not desirable.

Come the following day I arrived and promptly stood one of the little fuckers which had decided to make a break for freedom and had managed to reach the wet lab floor (RIP worm #10- your life was not wasted). Despite this poor start the day went well as the worms had hearty appetites and had eaten considerable amounts of the fish food pellets that I had offered them. Having retrieved what was left of these pellets I set about drying and weighing them to determine the dry weight lost from each so that I could work uot how much each worm had eaten. I was going to collect their faecal matter and the string of mucus the little blighters trail everywhere but then I remembered reading about how the residence time of food in the gut means that you should collect material from the 24 hours following feeding if you wanted to calculate absorption efficiencies. This I decided to do but instead of cleaning the worms out and leaving them to depurate in clean water I thought I would strike a balance between these two approaches and simply collect what was there 48 hours after feeding. In hindsight this was a bit daft. If I had been switched on I would have collected the excreta then and then collected the excreta for the following 24 hours seperately. As it happened, the next day it was clear that some worms had been doing their coprophage ting and had consumed some of their excreta from the previous day. Not to be discouraged I dutifully collected what was left by passing syringes of water from each trough through preweighed glass fiber filter discs and then dried and weighed each one. These were then ashed, along with the pellet residues from the previous day so that the organic content could be calculated. In reality there was a 10 day period between the drying and the ashing that encompassed xmas and NYE but the first thing I did when I got back into the lab this Monday was turn on the oven to ash my worm pooh.

Finally, having wacked the numbers into excel, I could view the results of my labours and was chuffed to bits to find that I had 23 data points with a beautifully tight SD, although with one outlier, admittedly. Even more chuffing brilliant was the 1-way ANOVA I did between the Avon worms AEs and some AEs I'd measured before xmas in worms from Restronguet Creek- my polluted site. The difference was clear and marked and was significant to P=0.001, which is pretty goddamn significant, I can tell you!

So there you go. Another success story of cutting edge research. Keep reading for my next adventure titled "The Return to The Polluted Site- The Hunt for More Restronguet Worms".

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