Submarine canyons are topographic features found along the continental slope worldwide. Here we use numerical simulations to study how a submarine canyon influences the circulation near the coast when winds moving poleward influence the region. Our results show that submarine canyons modify the circulation near the coast, causing strong velocities perpendicular to the coast. These changes can trap particles inside the canyon, an important mechanism to explain its role as a biological hotspot.

While the deeper waters in the coastal ocean show signs of climate-change-induced warming and deoxygenation, some fjords can keep cool and oxygenated waters in the subsurface. We use a model to investigate how these subsurface waters created during winter can linger all summer in Bute Inlet, Canada. We found two main mechanisms that make this fjord retentive: the typical slow subsurface circulation in such a deep, long fjord and the further speed reduction when the cold waters are present.

Understanding drivers of phytoplankton biomass in dynamic coastal regions is key to predicting present and future ecosystem functioning. Using a clustering-based method, we objectively determined biophysical provinces in a complex estuarine sea. The Salish Sea contains three major distinct provinces where phytoplankton dynamics are controlled by diverse stratification regimes. Our method is simple to implement and broadly applicable for identifying structure in large model-derived datasets.

Inland seas are critical habitats for globally important fisheries, and the local food webs that support these fisheries are often limited by surface nutrient availability. In the Strait of Georgia, which supports several key northern Pacific fisheries, we identify wind-driven upwelling as a dominant source of summer surface nutrients using a high-resolution coupled ecosystem model. This newly identified underlying mechanism will inform interpretations of ecosystem variability in the region.

Estuaries are vulnerable to ocean acidification, but present-day estuarine pH and aragonite saturation state variability are larger than in the open ocean. Using a numerical model of a large estuary and data from its primary river, we find that changes in river alkalinity relative to river carbon may determine a small but significant portion of this variability, while the majority is controlled by photosynthesis/respiration. Future watershed changes may shift the river alkalinity–carbon balance.