By Eric Solomon, director of Arctic programs, Vancouver Aquarium
“I don’t live 50 meters down, so why should I care what the temperature is?” asked a new friend in Gjoa Haven.
It’s a fair question, and I promise to answer it, but first some quick background:
It’s been a week since returning from Gjoa Haven, Nunavut after participating in the Canadian Ranger Ocean Watch (CROW) Exercise Polar Passage. As I mentioned in past posts, the CROW Polar Passage Exercise is a collaboration between the Department of National Defense’s Canadian Rangers, Fisheries and Oceans Canada (DFO) and the Vancouver Aquarium.
The Canadian Rangers are local (Arctic) Inuit hunters that are reservists in the Canadian military. They know the Arctic better than anyone. Our goal was to train the Rangers to use specialized equipment to collect oceanographic data while out on patrols or hunting. Because they travel frequently, over long distances and throughout the year, the opportunity to collect never before known information about the Arctic Ocean is unprecedented and very promising. Dr. Bill Williams, an oceanographer with DFO, was the lead scientist on our trip, and was very excited about the collaboration because until now, this kind of information was only gathered while aboard icebreakers during the short summer months.
The sampling process involved drilling a hole through the ice to the ocean below…
… and lowering a device that takes various types of measurements. The device is called a CTD, which stands for Conductivity, Temperature and Depth.
As we lowered the device from the surface to the bottom, it took continuous measurements of the depth, temperature, conductivity (which tells us how salty the water is), dissolved oxygen, and how much chlorophyll is present in the water (a measure of how productive the area is).
Now back to that “why” question posed in the beginning. Why do DFO scientists care what the temperature or salinity of water is 50 meters below the surface? Why should anyone care?
The key to answering that question is to realize that the Arctic Ocean is not a single body of water from the seafloor to the surface – it’s made up of a number of layers that frequently don’t mix at all. You’ve probably seen how oil and water separate and the oil stays at the surface. The same can happen with very salty water (which sinks) and relatively fresh water (which rises), or water at different temperatures. It would take a storm or currents to get these layers to mix. How, when and where that happens does matter because the most nutrient-rich water – the water that fertilizes the entire marine food chain – is usually at the bottom. Anything that affects how water moves in the ocean ultimately affects where things can live and how much can live there.
So let’s say you’re an Inuit hunter who relies on seals, walrus, narwhal and belugas to feed your family and earn some income. The abundance of wildlife and where you can find it are directly linked to the various processes that cause layers of ocean water to mix and move. Those processes are poorly understood throughout the Arctic Archipelago – and they are likely changing rapidly as the northern climate changes.
I’m pretty sure I just heard you say, “I don’t hunt seals so I guess I’m OK, though, right?” Not so fast. The Arctic Ocean temperatures may have a greater impact on you than you might have thought. Every year in the summer, a portion of the sea ice melts. The water that is exposed soaks up the sun’s heat and warms up. Then, in the fall when the air temperature drops, that water freezes back up. Areas where there is permanent ice cover don’t experience the same kinds of seasonal water temperature changes. That’s been the case for a very long time. But more and more ocean is being exposed in the summer as older, thicker ice melts away.
The more ocean that’s exposed in the summer, the more heat is absorbed by the water, the longer it takes to freeze again in the fall, and the less ice you get overall. How exactly will that affect you? Stand by as we all find out. This is complex stuff, but the changes in Arctic ice, currents and temperatures are big enough to impact climate and weather throughout the world. Scientists like Bill Williams are in a race with time to try and understand just what those impacts will be.