Inside the bodies of giant humpback whales are clues about how climate change is transforming Antarctica. As sea ice continues to decline at an alarming rate in the fragile Antarctic Peninsula, scientists working with the wildlife charity WWF are carrying out up-close health checks on the massive marine mammals there. The BBC's Victoria Gill and Kate Stephens crossed the Southern Ocean, with the researchers, on a mission to follow and study the whales of this remote, frozen wilderness.
It is an important question - not just for mighty, 40-tonne humpbacks that travel thousands of kilometres to gorge themselves in the cold seas - but for the health of the ocean and our planet. Cloud is descending and it is starting to snow. Leading our Antarctic whale research mission is Chris Johnson, who is the wildlife charity WWF’s global expert on whale conservation.
It’s a mother, side-by-side with her calf. She seems intrigued - circling our boat slowly, then gliding directly underneath. Her giant head and white pectoral fins - fringed with barnacles - are visible as she slowly floats beneath us. The health of whales, he explains, shines a light on the health of the whole Antarctic ecosystem. And whales are physically necessary for a healthy ocean: Humpbacks eat krill, and krill eat microscopic plants that live in sea ice - plants that absorb planet-warming carbon as they grow. Whales then poop and fertilise the marine plants.
Most mature humpbacks here will eat about three million Antarctic krill each day, as they bulk up for a 8,000km journey back to breeding grounds in the tropical Pacific.From the drone, researchers can study feeding behaviour and measure the whales' bodies to find out if they are getting enough food The drone doesn’t just provide a spectacular view - it’s used to weigh the whales. Chris explains: “We measure the length and width of their bodies to work out how fat they’re getting during the season.”
The waste has the aroma of highly concentrated rotting fish, but Sarah is delighted. “Whale poop is so hard to find and it contains all this information about what they’re eating. We can even get DNA and hormones from it. It’s liquid, smelly gold!”Back aboard the ship, the team use a store room as a makeshift laboratory. At a small table, Natalia and Sarah take each sample from its arrow-tip casing and put it in a sealed tube to be transported back to Natalia’s lab.