The Equator is a great circle around the Earth that is everywhere equidistant from the geographic poles and lies in a plane perpendicular to the Earth’s axis. This geographic, or terrestrial, Equator divides the Earth into the Northern and Southern hemispheres and forms the imaginary reference line on the Earth’s surface from which latitude is reckoned; in other words, it is the line with 0° latitude. (Source Encyclopaedia Britannica)

The Guinea Current is a surface oceanic current of the Atlantic Ocean, the eastward continuation of the Atlantic Equatorial Countercurrent, off the western coast of Africa near the Gulf of Guinea. Always north of the equator, the southeastward-flowing Guinea Current changes position with the seasons so that its northern limit lies at approximately latitude 7° N during the winter and latitude 15° N during the summer. The warm, highly saline Guinea Current reaches a depth of less than 660 feet (200 m). (Source Encyclopaedia Britannica)

The Tropic of Capricorn is a latitude approximately 23°27′ S of the terrestrial Equator. This latitude corresponds to the southernmost declination of the Sun’s ecliptic to the celestial equator. At the winter solstice (Northern Hemisphere), around December 21, the Sun is directly over the Tropic of Capricorn and lies within the boundaries of the constellation Sagittarius, having reached its southernmost declination in the ecliptic. Previously, however, it appeared in the constellation Capricornus at the winter solstice, hence the name Tropic of Capricorn. (Source Encyclopaedia Britannica)