Limnology Part 2

We started today with a biology lecture, concentrating on the phyto- and zooplankton that we would be looking at later in the day. Whilst the other took a break, I accompanied one of the centre staff down to the weather station to get a closer look and see how they take measurements. It helped to bring things to life, and was good revision for my course, especially seeing how the hours of sunlight are measured.  This is done using a Campbell-Stokes sunshine recorder - the instrument focuses the Sun's rays through a spherical glass lens and on to a piece of card, scorching a line on to the "burn card" every time the Sun emerges from behind the clouds. Sunshine hours correlate to the length of the burn. There are different slots for the card depending on the season, as the sun is at a different level in the sky.

After the mid-morning break, we all kitted up and got ready to face the wind and rain on the lake.  The rain wasn't too heavy, and my new waterproof jacket kept me dry. We took both boats out at once, and took it in terms to collect phyto- and zooplankton samples. Nets of different mesh sizes were used for each, and the method also varied.  Phytoplankton float so the net was pulled horizontally for 2 minutes, just below the surface of the water. Zooplankton are noctural and more likely to be lower down in the water column, so they are collected using a vertical sample. We then dropped anchor and used it to pull up some macrophytes (plants) growing on the bottom of the tarn.

After lunch, we settled back into the lab and set up microscopes to see what we had found. The tutor was a bit dissappointed that we hadn't found any diatoms, but I was more than impressed with the range of phytoplankton I found which included anabaena, microcystis, gleotrichia and ceratium.  Volvox (pictured) was particularly pretty. I could have spent hours looking at it. We were a bit less successful with the zooplankton, and I found it quite hard to identify things - I know it was a copepoda but couldn't be more specific - more practice needed! 

The course finished mid-afternoon, and after a brief wrap up session we were on our way. Naturally I hit the rush hour traffic so it took nearly two hours to drive home. I treated myself to a hot bath to recover from a tiring but very enjoyable few days.  Just a few days at home, and then I am going to Bristol for the week, attending International Penguin Conference 8 (IPC8). I am sure much of it will be over my head, but it will be good to meet the guys from South Africa again and catch up on their research.