Canada’s Oceans Now: Arctic Ecosystems 2023 - Canadian Arctic inflow and outflow: gathering data over time

Canadian Arctic inflow and outflow: gathering data over time
We need data that is gathered consistently over a long period (20 years or more) to confidently identify change in ocean water

On the top left, a box containing an illustration shows how ocean data is being collected where waters enter the western Canadian Arctic on the Mackenzie Shelf. Water is monitored at one depth near the sea floor. Arrows in the background of the illustration are going from left to right, showing the flow of water passing by an immobile monitoring instrument tethered to the sea floor. Three dark blue boxes containing white explanatory text are in the middle of the illustration, stating:

• Long-term trends
• Water is slightly warmer, warming less than 0.1 °C per decade
• Salinity shows no change over the last 30 years

On the top right, an illustration shows how ocean data is being collected where waters are exiting the eastern Canadian Arctic through Barrow Strait. Arrows in the background of the illustration are going from left to right, showing the flow of water passing by two monitoring instruments tethered to the sea floor. These instruments move up and down, monitoring water and gathering real-time data at all depths. Three dark purple boxes containing white explanatory text are in the middle of the illustration, stating:

• Long-term trends
• Water is slightly warmer, warming less than 0.1 °C per decade
• Salinity has slightly decreased across all seasons and depths

Between these two illustrations, a map shows the two monitoring locations. A blue dot represents the long-term monitoring location on the Mackenzie Shelf in the western Canadian Arctic. A purple dot represents the long-term monitoring location in Barrow Strait in the eastern Canadian Arctic. Texts at the top states:

• Data gathered over the last 30 years shows long-term trends

On the bottom left, a text box explains how waters near the sea floor on the Mackenzie Shelf experience warming events, stating:

• “Warming events occur in bottom waters far from the sunlit layer. During these events, bottom water temperature can be several degrees warmer, and the warming can last from a few days to multiple seasons.”

To the right, three illustrations show how these warming events occur, with typical temperatures depicted in blue and warming events depicted in orange.

• The left-most illustration shows how warming events can arise from summer downwelling, when west winds drive warmer surface water downwards. A vertical cross-section of the water shows the air, water, and sea floor layers. The surface layer of the water is orange, while the rest is blue. Arrows moving from left to right in the air layer depict the west wind. Arrows within the water flow from the warmer orange surface layer down towards a monitoring instrument tethered to the sea floor.
• The middle illustration shows how warming events can arise from winter upwelling, when warmer, deeper waters are pushed onto the shelf by east winds. A vertical cross-section of the water shows the sea floor rising up to form a shelf on the right. Water at the bottom right is orange, while the rest is blue. Arrows within the water flow from the warmer deeper water up to a monitoring instrument at the top of the shelf.
• The right-most illustration shows how warming events can arise from horizontal inflow, when water flowing around Alaska brings heat to Canadian waters. A map of Alaska and the western Canadian Arctic shows arrows surrounded by warmer orange water flowing through the Bering Strait, around the north of Alaska, and east onto the Canadian Mackenzie Shelf.