It’s difficult to overstate the significance of krill. A species that is among the most numerous animals on earth, they are not only a vital food source for many large marine mammals but play a crucial role in removing up to 40 million tonnes of carbon each year. So, when climate change starts to impact upon the numbers and habitats of such a keystone species in the ecosystem, scientists are going to start taking the matter seriously.

Which is precisely what a new consortium of scientists, led by the brains at the Natural History Museum, has been established to do; undertaking a new UKRI Natural Environment Research Council-funded project to investigate how Arctic Krill is being impacted by the Anthropocene.

Known as KrillGuard, the project aims to protect the Southern Ocean ecosystem by focusing on this vital oceanic species, looking specifically at how – as rising ocean temperatures cause the krill’s habitat to shrink – the species is adapting to climate change.

To study how the animal is being impacted by the Anthropocene, KrillGuard researchers have developed DNA probes to identify important genes within the krill’s sequenced genome. They aim to target 10,000 gene sequences, including those associated with the krill’s response to temperature.

These krill specialists will then compare historic specimens from within the Natural History Museum archives with krill collected more recently by the British Antarctic Survey to observe and record how these genes have changed over the past century.

While krill are just a few centimetres long, their genome is one of the longest animal genomes sequenced to date, coming in 16 times longer than a human’s. The size of the krill’s genome means it was only sequenced for the first time in 2023 when scientists discovered that its extreme length is a result of repeated DNA sequences – the purpose of which still remains unclear.

Dr Matt Clark, research leader at the Natural History Museum and senior member of the KrillGuard team, said: “It’s hard to overstate just how important Antarctic krill are to the ecosystem. As many as 10% of them are fed on by whales alone, while many more are eaten by everything from sea birds to squid.

“As cold-water specialists, krill are vulnerable to the effects of the warming Southern Ocean. We hope that by improving our understanding of their genetics, we can find out more about their populations and support decisions to conserve this vital species.”

Alongside the Arctic krill’s crucial position in the food chain and its key role in the carbon cycle, it’s also a species bearing a considerable commercial importance. The krill fishing industry has an annual catch value exceeding $200 million. 

The project also hopes to resolve an ongoing mystery around krill. 

While the invertebrates are treated as one large population surrounding the whole of the Antarctica, it’s possible they might form distinctive groups. Should this prove to be the case, then as the climate warms, some of these subpopulations may be affected more than others.

It also means that certain subpopulations – which may be fished in open waters – might be the ones better adapted to higher temperatures. 

“It’s possible that the krill that get fished are the ones better adapted to higher temperatures, allowing them to move into open waters,” explains Dr Clark. “If this is the case, then we might be hampering krill’s ability to adapt to rising ocean temperatures by removing the genes from the population that make them able to cope.”

The outcome of KrillGuard’s research could go on to be used by international bodies such as the Commission for the Conservation of Antarctic Marine Living Resources to better manage the continent’s waters. 

KrillGuard will be running a one-day workshop at the Natural History Museum where it will bring together representatives of regulatory bodies responsible for marine life preservation to share the findings of the project.

“In collaboration with Antarctic treaty organisations, we might be able to introduce protected areas where fishing is prohibited,” continued Dr Clark. “These could preserve krill with useful genetics to help repopulate zones under fishing, and could potentially move from year to year.

“Ultimately, we will provide our results to the treaty organisations, and it’s up to them to decide what they want to do with it.”

Click here for more from the Oceanographic Newsroom.