Each year some of our students undertake summer projects and this year was no different. Here’s an account of Msci Plant Science student Helen Feord working as part of Dr Jon Pittman’s lab to research more into metal pollution. This project was supported by a Faculty of Life Sciences Sustainability studentship.
Metal pollution creates hostile environments, but many different organisms persevere and survive in these extreme conditions. Our understanding of such polluted ecosystem comes from characterising their biodiversity and the presence of extremophile (living in extreme environment) organisms. As part of a summer project, funded by the sustainability studentship, plant science student Helen Feord investigated biodiversity from the abandoned copper mine, Parys Mountain, in north Wales. Working in Jon Pittman’s lab, Helen identified organisms from ponds from the abandoned mine by using ribosomal marker sequence identification and then comparing the unknown DNA sequence with known database sequences. Amoebas, fungi, an acidophilic bryophyte and golden alga were some of the organisms found.
To examine these organisms further, Helen focused in particular on the Chlamydomonas acidophila alga. This alga lives in incredibly acidic conditions (in a pH as low as 2) and has a high tolerance to metals such as zinc. There was an interest in knowing if the amount of zinc present in the water that they lived in had an influence on their tolerance for the metal. Indeed Helen looked at zinc tolerance by comparing the growth of C. acidophila isolated from different ponds and found a difference in zinc tolerance between C. acidophila from the various ponds. However there was no apparent link between the zinc tolerance of C. acidophila and the zinc concentration in the pond they came from, meaning that, in this context, high zinc concentrations did not induce high zinc tolerance.
Furthermore by testing C. acidophila survival and growth at different zinc concentrations, Helen found tolerance surpassing 50 mM zinc. Helen also compared the metal tolerance of genetically modified Chlamydomonas reinhardtii, a model species suitable for genetic analysis. Transgenic strains had they had been genetically modified to express plant proteins that bind metals, and thus have the potential to tolerate metal better. Interestingly, compared to these genetically modified algae, C. acidophila zinc tolerance was much higher. However for Cadmium, both species had a similar tolerance.
This emphasised the high metal tolerance of C. acidophila and this knowledge is particularly useful as this organism has the potential to be a solution for metal pollution, a concept called bioremediation, the use of living organisms to solve environmental issues like this one. Indeed C. acidophila appears be so metal tolerant because of its ability to uptake the metal. But this still needs to be investigated further so that we can continue to look for ways to use this organism in bioremediation.