Wastwater, Cumbria
![sampling in Wastwater](Images/Wastwater_sampling.jpg)
Wastwater, in the English Lake District, is as close to pristine as any lake in England, as the surrounding catchment
is mostly moorland and rough grazing, with a very low human population density.
The pictures from Wastwater form a series based on experiments done by my colleague Lydia King during her PhD
studies. She studied the algae growing on stones in the littoral zone around the lake and I used her data as the
starting point for a series of pictures. The aim of her study was to see how the algal communities changed over
the course of a six week period, as they colonised bare surfaces.
![Wastwater, 2 weeks](Images/wastwater_2weeks.jpg)
The first picture shows the surface of a rock after being submerged in the lake for two weeks. There are a mixture
of small green and blue-green algal cells plus a few thin filaments of the blue-green alga Phormidium along with
the diatoms
Achnanthidium minutissimum and
Gomphonema parvulum. At this stage, there were about 1800 cells per
square centimetre.
![Wastwater, 3 weeks](Images/wastwater_3weeks.jpg)
A sample collected a week later shows the density of algal cells to have increased to about 9000 cells per
square centimetre, with competition for light becoming more intense.
![Wastwater, 5 weeks](Images/wastwater_5weeks.jpg)
Five weeks after the start of the experiment and long-stalked diatoms such as
Gomphonema acuminatum and
Cymbella affinis are able to outcompete the short-stalked
Achnanthidium and
G. parvulum. Chains
of
Tabellaria flocculosa are also tangled amidst the upper layers of the biofilm. There are now just over
31000 cells per square centimetre.