How do ocean currents form?
Ocean currents are large-scale directed movements of seawater. Wind, density differences, tides, coastlines, and Earth's rotation all contribute. Surface currents and deep-water circulation cannot be reduced to one mechanism.
Wind-driven and density-related circulation
Wind transfers momentum to the surface, while rotation and basin boundaries shape large circulation patterns. Temperature and salinity affect density; dense water sinks in some regions and joins deeper circulation. Mixing, upwelling, and seafloor topography also matter. The global conveyor-belt analogy is useful but simplifies a variable interconnected system with many pathways.
Climate, nutrients, and observations
Currents transport heat and dissolved substances, affecting regional climate and marine ecosystems. Upwelling can bring nutrients toward the surface, but not every current produces equal biological productivity. Floats, drifters, ships, and satellites provide complementary observations. A short-lived coastal change does not prove global circulation has stopped; long records and physical models are needed to assess trends.