Tracking Ocean Currents

Do ocean currents inside Greenland's fjords regulate the speed of mass loss from the ice sheet? What controls the onset and strength of low oxygen events in Puget Sound, WA? Though seemingly unrelated, questions like these underline the importance of understanding how coastal ocean processes can interact with estuaries prone to sensitive environmental issues, such as Greenland's fjords or Puget Sound.

Over the last decade, observations in Greenland have shown the ice sheet to be losing an increasing amount of mass, with evidence pointing towards an ocean source as the cause. However, oceanographers' understanding of how the fjord circulation works, which connects the outlet glaciers to the continental shelf, is extremely limited. Dr. Sutherland's research is aimed at describing the processes that control the currents inside these fjords, such as Sermilik Fjord in southeast Greenland (left), by measuring water velocities, temperature and salinity (or “saltiness”) within the fjord. Dr. Sutherland and colleagues have found warm, Atlantic-origin waters penetrating the deep parts of Sermilik Fjord, which is close to 3000 feet deep (>1/2 mile!). The presence of this relatively warm water in close contact with the ice may play a role in driving glacial melt (read more).

In Puget Sound, a large fjord in Washington, coastal ocean processes also significantly impact the estuary. Puget Sound is home to millions of people in the greater Seattle area, and this population stress has been implicated in an increasing trend of hypoxic, or low-oxygen, events in some areas of the Sound. However, isolating the human effects on the Sound versus what is brought in from the coastal ocean naturally is difficult. Dr. Sutherland has developed a numerical computer model to simulate the ocean currents in Puget Sound (right) and to improve our understanding of the estuary functioning. With this tool, we aim to make predictions of what variables, such as tidal strength, winds, and/or river discharge, and what areas, such as Admiralty Inlet, affect Puget Sound the most. These predictions can help coastal managers set policy for fisheries and aquaculture, as well as aid in site identification for future tidal energy projects (read more).