What devises measures currents?
An ammeter, or multimeter (which includes an ammeter setting).
intrauterine devises does not cause infertility in most cases. Very rarely, infection is introduced with the intrauterine devises. Such infection may go to the fallopian tubes and may block the tubes. This may result in infertility. This type of phenomena in common in developing countries, where quacks may introduce the intrauterine devises. They are not properly trained. This is rare in developed countries.
Deep ocean currents are in the depths of the oceans. Surface current are at the surface, not deep down. Deep ocean currents bring vitamins and nutrients to the shore, surface currents do not. Deep ocean currents are caused by salinity and temperature differences. Surface currents are cause by the force and impact of the wind.