‘Ring of Fire’ is a four-year research project that investigates how rising temperatures of global warming could affect freshwater ecosystems. A team of scientists are visiting five high-latitude sites where geothermal activity generates a temperature gradient across freshwater streams. The streams are used as ‘natural laboratories’ to investigate how global warming could impact everything from gene expression to whole ecosystem processes, in systems that are experiencing warming at an unprecedented rate. Dr Kate Randall, who has recently returned from fieldwork in Russia, explains why this project could revolutionise future research into global warming.
Kamchatka, a remote volcanic peninsula in the far east of Russia, was the fifth and final site to be sampled by the ‘Ring of Fire’ team. Our field site was located in the Verkhne-Paratunskie Hot Springs Nature Reserve, an hour drive along a hazardous road that caused three punctures in two days and led to one unintentional diversion into a ditch. Reaching the streams themselves, by clambering through dense vegetation, was another challenge – but it was worth it. In total we sampled ten streams spanning a gradient of 6.5 to 31 degrees Celsius.
My involvement in the ‘Ring of Fire’ fieldwork focuses on the microbial communities living in the sedimentary layer of these streams. Sampling consists of collecting sediment and freezing it to preserve a snap-shot of the microbial community. The samples are then processed back in the lab at the University of Essex. Despite being invisible to the naked eye, microorganisms are arguably the most ecologically significant group of organisms on the planet. They drive the biogeochemical cycling of nutrients such as carbon and nitrogen, support ecosystem processes and ultimately influence the services ecosystems provide. However, data concerning freshwater microbial responses to global warming, and their inclusion within ecological freshwater food web research, is lacking.
This is partly due to the microscopic size and high abundance of microorganisms in the environment, which means traditional ecological methods used to study larger organisms are not applicable to microbial ecology. But, thanks to technological and computational developments, I can bypass these problems. In the lab, I can extract and purify genetic information, which allows me to identify and quantify what microbes are present and what specific functions are being performed – and compare the results across the temperature gradients at each of the sites.
Gathering this data at such a scale is unprecedented, and will bridge major knowledge gaps in global warming research for freshwater ecosystems. Working with Dr Sarah Harpenslager, who is measuring key biogeochemical processes associated with carbon and nitrogen cycling, our combined data will enable us to track changes in microbial communities, and link these to the ecosystem processes they drive.
Over two years, the ‘Ring of Fire’ project has achieved multidisciplinary ecological research at a huge scale, from genes right up to ecosystem level, and established a standard sampling strategy. Few studies investigate the effects of temperature on multiple ecosystem processes; even fewer incorporate increased levels of biological complexity; and fewer still attempt to combine the two. I have no doubt our work will act as a showcase for a new approach to global warming research, at a time when it is more important than ever.