Studying 150 year old arctic algae samples

An insight into how the waters around the Arctic have changed over the last century and a half has been hiding on a shelf in London’s Natural History Museum. Samples of cyanobacteria, also known as blue-green algae, were taken by naturalists on an expedition aboard the HMS Challenger 150 years ago, brought back to London and stored. Now scientists are reading the genetic makeup of these samples and comparing them with their modern-day counterparts to see how they have changed. Telling Will Tingle what they’ve found so far, the Natural History Museum’s Anne Jungblut…

Anne - The samples were collected as part of the British Arctic expedition. That was in the late 19th century. So it was the expedition led by Captain George Nares and they were the first recorded Europeans that reached the Norse end of Ellesmere Island. So they were trying to find the North Pole. However, then it became winter and they had to stay in winter at one of the shores along Ellesmere Island. And I think the conditions were pretty bleak. It was pretty cold. They probably didn't have the right clothing and food and they had scurvy. But them being keen Victorians and natural historians, they spent their time doing a lot of historical collections. And as part of this, they also documented the microscopic life they found. And as part of this, they collected samples of cyanobacteria that were brought back to the Natural History Museum and have been stored at the Natural History Museum since the 19th century.

Will - Did the samples manage to stay sufficiently preserved over this period of time?

Anne - So that was one of the first big questions we had for our research project. So we have these specimens, which really look like dried slime, kind of like slime maybe if there is a puddle somewhere and there are green things growing and then it dries. And then you have this soft dried slime. And so one of our first questions was, can we get DNA out of these samples because, now they're dried, it's really hard to see anything if we used a microscope. And so we were really lucky we got DNA out of the samples and sufficient DNA to get the genome of the samples.

Will - And when you compared the genome of those samples against samples from nowadays, what differences are you looking for that implies that there's been a change in the conditions in the Arctic?

Anne - Microorganisms. We can't see flowers and fish. And so we need to use the DNA as our visual lens to see what they might have looked like and what they could have done. The species that we found in our collections are still present in modern samples and we also found that some of these species seem to more commonly occur in the polar regions rather than in other climatic zones. So that means if it gets warmer in the Arctic or we lose the ice shelves, we might lose these species. And in the genomes we found that they were able to contribute to fixing nutrients, we found that the Arctic samples and also the ones we had in our collections had lots of compounds that are of potential interest for developing new medical drugs. And so going forward we really want to unlock the information that is in these cyanobacteria collections.

Anne - We also want to find out if there are other organisms in the old samples that might be diseases or a threat to these ice shelf communities. So potentially, if it's getting warmer, there might be more diseases coming to the Arctic. We also want to find out if there are any invasive species. So having looked at the old samples and the new samples and seeing if we find any potentially invasive species that might have been brought there through human activity like Europeans travelling there, or just the transport through on wings of birds who might have transported organisms from other climatic zones.

Will - So yet more good reasons to try and stop the Arctic from melting then?

Anne - Yeah, exactly. So the era we are working in, it's called the Last Ice Area. So there have been international researchers, local communities, NGOs have got together and they've calculated what areas of the arctic ice are going to melt last, so what is the ice that's going to be there the longest? And they've found out that actually these ice shelf systems are part of the area that's going to be there the longest. And now there is increased international effort to really document what's living there and find out what is there and if we can protect it or see how the life living there is is related to other parts of the globe.