Surface wetlands are primarily supported by which of the following?

Surface wetlands are primarily supported by runoff, which consists of the water that flows over the land surface during and after rainfall events. This runoff contributes to the hydrology of wetlands by adding water, nutrients, and organic matter, which are essential for maintaining the wetland's ecosystem.

Runoff is particularly important in areas where surface water inflow is limited, as it can help sustain the water levels necessary for wetland vegetation and wildlife. The wetland's ability to filter pollutants and improve water quality is also enhanced by the sediment and nutrients brought in by runoff.

While groundwater sources, direct rainfall, and oceanic tides can play a role in maintaining certain wetland types, they are secondary to the dominant process of runoff. Groundwater sources support wetlands primarily through the saturation of soil rather than surface water supply, direct rainfall provides intermittent water but does not consistently sustain wetland hydrology, and oceanic tides are relevant mainly to coastal wetlands rather than surface wetlands in general. This emphasizes the crucial role that runoff plays in nurturing and supporting surface wetlands as vital ecosystems.