The role of topography in cross-shelf-break exchange

海底峡谷是通常出现在大陆架和陆坡上的水下峡谷。峡谷促进了沿海海洋和深海之间的水交换。它们在将深水带到大陆架（上升流）方面很重要。这些水富含对支持沿海渔业生产的植物生命至关重要的营养物质。不列颠哥伦比亚省海岸外的胡安·德·富卡峡谷是一个引起显著上升流的峡谷。然而，其他峡谷引起大陆架水向海洋的显著运动（下流）。新斯科舍海岸附近的沟壑就是一个例子，它最近被列为海洋保护区。通过数值模拟、实验室模拟和观察，我们将了解像沟壑这样的峡谷如此多产的过程。通过建立对上升流和下升流峡谷的理解，我们将能够预测由于海底峡谷而导致的沿海和深海之间的水交换将如何由于洋流或分层的变化而变化。它将使我们能够预测交换水的数量和深度。由于沿海海洋通常比开阔的海洋更富有生产力，因此沿海海洋中的植物形成了更多的碳。将这些碳输送到深海是海洋碳循环的一部分。了解沿海海洋和深海之间交换的水量和深度是量化这部分循环的必要条件。

Submarine canyons are underwater canyons that usually occur on the continental shelf and slope.  Canyons enhance water exchange between the coastal ocean and deep ocean.  They are important in bringing deep water onto the shelf (upwelling).  This water is rich in nutrients important to the plant life that supports productive coastal fisheries.  Juan de Fuca Canyon off the coast of British Columbia is a canyon that causes significant upwelling. However other canyons cause significant movement of shelf water into the ocean (downwelling).  An example would be The Gully off the coast of Nova Scotia which was recently made a Marine Protected Area.  Using numerical modelling, laboratory modelling and observations we will gain an understanding of the processes that allow a canyon like The Gully to be so productive. By building an understanding of both upwelling and downwelling canyons we will be able to predict how the water exchanged between the coastal and deep oceans due to submarine canyons will change due to changes in ocean currents or stratification.  It will allow us to predict the amount and depth of the water exchanged.  As the coastal ocean is in general more productive than the open ocean, more carbon is formed into plants in the coastal ocean.  Transport of this carbon to the deep ocean is part of the ocean carbon cycle.  Knowing the amount and depth of water exchanged between the coastal ocean and deep ocean is necessary to quantify this part of the cycle.