The polar regions of the world are among the most unique ecosystems on our planet. Perhaps because of their inaccessibility and relative lack of human presence, the consequences of global climate change on polar ecosystems is easily overlooked.
The polar regions of the world are among the most unique ecosystems on our planet. Perhaps because of their inaccessibility and relative lack of
human presence, the consequences of global climate change on polar ecosystems is easily overlooked. We do this at our peril however, since the pace and extent of global warming trends are nowhere more alarming than in polar regions. The potential consequences of climate change will be devastating for human populations living far beyond the ice. The outcome of some changes is predictable (such as drastic sea level rise resulting in loss of densely inhabited and fertile coastal land). Much less predictable are the effects of changing ocean circulation patterns on the earth's climate if we should lose (as many now predict) a permanent Arctic ice cap, and the vast ice-sheets of Greenland.
Perhaps the global nature of the threat makes it less surprising to find a team from Portugal participating in European Polar research, within the project ATP (Arctic Tipping Points). The overall goal of ATP is to bring together past records, experimental approaches and predictions from physical-biological models to identify "tipping points"; key elements of the ecosystem that might be susceptible to abrupt change (irreversible on human time-scales). Gathering together partners from Norway, Spain, Poland, Portugal, United Kingdom, Denmark, Greenland, Germany, Russia, Sweden and France, ATP also brings together many scientific disciplines, from the biological and physical sciences, to economists and social scientists in an effort to identify thresholds for drastic change, and to evaluate the resulting risks and opportunities.
The CCMAR team from Portugal (Xana Ramos, Ester Serrão and Gareth Pearson) is studying the effects of climatic changes on the biodiversity of Arctic communities of phytoplankton - tiny single-celled algae, which turn carbon dioxide and sunlight into food (the role played by plants on land), thereby sustaining the complex web of more emblematic Arctic species - ultimately including whales, polar bears, and indeed human communities. But what is very different in their approach is that they are looking inside the cells at the smallest level of biodiversity that exists - the genes. Although all the genes of living organisms are encoded in their DNA, only a proportion are actively working - being expressed - at any given time. When a set of genes is needed they are copied, or transcribed, into RNA and then into the proteins that do the work within the cell. Transcriptomics is the study of RNA expressed in a single species at the whole genome level, and metatranscriptomics is a more complex version, in which a community of species is examined together. The CCMAR researchers intend to sequence metatranscriptomes - hundreds of thousands of RNA molecules from natural communities, allowing them to identify the set of proteins being produced and their relative abundances. This will produce a snapshot of the status of natural communities - for example what stresses, nutrient requirements, or repair and maintenance processes are operating. By looking at both community structure and metatranscriptomes under future climate scenarios, which include serious increases in sea temperatures, it is hoped that some of these genes may prove to be useful molecular "alarm bells" alerting us to potentially irreversible ecosystem changes - before the tipping point is reached.