Many organisms have been forced to adapt to the changes brought on by climate change. Their survival has depended on it. The zooplankton Calanus finmarchicus has not been left untouched by this phenomenon, new research shows. A main source of food for scores of fish, Calanus finmarchicus now lives in the cold North Atlantic and North Sea waters after being forced to move north some 18,000 years ago. The findings were recently published in Proceedings of the Royal Society B. Researchers from Queen's University, Belfast, UK have discovered that Calanus finmarchicus responded to global warming after the last Ice Age. Experts believe an outcome of climate change is a forced shift in the distribution range of the species. The plankton moved north and has succeeded in maintaining large population sizes. The new finding is significant because it provides evidence that the species has a feature that helps it cope with global warming. 'Our results, in contrast to previous studies, suggest that the species has been able to shift its distribution range in response to previous changes in the Earth's climate, and thus "track" the effects of climate change, a feature which may be of crucial importance in its survival,' explained Dr Jim Provan from Queen's School of Biological Sciences. 'The genetic variability of the species - the tendency of the genetic make-up of a population to vary from one individual to another - has remained high, which is good news, and suggests that these animals might be able to track the current change in habitat resulting from global warming and maintain viable populations sizes.' Dr Provan went on to say that failure of the species to track the change would have a huge adverse impact on its survival. 'It might become extinct and thus threaten the fish species that depend upon it for food,' the researcher said. He stated that while no one should jump to conclusions as regards the effects of climate change on marine resources, it is better to be vigilant as to what can happen. Past studies on the Calanus finmarchicus have shown that the number of the species and the size of the population have dropped significantly. 'Decreases in genetic variability' may be the culprit, he said. Such variability may play havoc with the adaptive potential of the populations in future. The researchers of this study believe this could trigger the extinction of species. Experts have said the species is believed to be one of the most important components of the regional marine food web. The team will continue their work to investigate how the results of the study apply to rapid global warming over the past few decades.