A fjord is a long, narrow, deep inlet of the sea that is typically carved by glacial erosion. These geological features are characterized by their steep sides and deep, U-shaped cross-section, resulting from the abrasive action of immense ice masses that scour the bedrock. Following the retreat of the glaciers, these troughs become flooded by the ocean, creating the distinctive fjord environment. The unique bathymetry and stratification within a fjord often result in density gradients, where fresher, lighter water from rivers may sit atop denser, saltier, deeper oceanic water. These physical characteristics influence the distribution of marine life and the local hydrodynamic regime.