The effect of global climate change on the planet's ecosystems is one of the key issues scientists are currently focusing on and, while there isn't a lot of good news, there is some; the main source of food for many fish, including cod, in the North Atlantic appears to adapt in order to survive climate change.

Billions of Calanus finmarchicus, a plankton species, which are just a few millimeters in size, live in the waters of the North Atlantic where the research was carried out. It showed they responded to global warming after the last Ice Age, around 18,000 years ago, by moving north and maintaining large population sizes and also suggests that these animals might be able to track the current change in habitat.

Calanus finmarchicus, a zooplankton species, is considered one of the most important components of the regional marine food web.

“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," say study leader Dr. Jim Provan, from the Queen’s University Belfast 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 population sizes.

“If the species couldn't, it might become extinct and thus threaten the fish species that depend upon it for food. “It might be a rare example of news that may not be doom-and-gloom with respect to climate change, but it doesn’t mean that we don’t have to keep watching what happens.”

Previous work on the species had indicated a serious drop in numbers and decreases in population size may be reflected in decreases in genetic variability.

This can compromise the adaptive potential of the populations for the future and possibly result in extinction.

As a result of the Queen’s findings the team is planning further work to see how the study applies to rapid global warming over the last few decades.

The other Queen’s academics involved in the paper were Professor Christine Maggs, Dr Graham Savidge and students Gemma Beatty and Sianan Keating.

Article: 'High dispersal potential has maintained long-term population stability in the North Atlantic copepod Calanus finmarchicus', Proceedings of the Royal Society B.