Marine current power the rotation of the earth. The sun acts as the primary driving force, causing winds and temperature differences. Because there are only small fluctuations in current speed and stream location with minimal changes in direction, ocean currents may be suitable locations for deploying energy extraction devices such as turbines. Other effects such as regional differences in temperature and salinity and the Coriolis effect due to the rotation of the earth are also major influences. The kinetic energy of marine currents can be converted in much the same way that a wind turbine extracts energy from the wind, using various types
The Formation of Vegetable Mould through the Action of Worms distance in a given time. Some also roll down, and collect in drains etc., or get blown. There is a greater effect on casting movement in the tropics, because of increased rain. The finest earth is washed away. Ledges on hillsides, formerly believed to be caused by grazing mammals, are partly due to casting accumulations. High winds, especially gales, are almost as effective as the slope/rain in moving castings. Crowns and furrows of formerly ploughed lands slowly vanish when under pasture, due to worms, but more slowly when there is no incline. Fine earth is washed down from slopes, making