Upwelling
The major upwellings in the ocean are associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. There are at least five types of upwelling: coastal upwelling, large-scale wind-driven upwelling in the ocean interior, upwelling associated with eddies, topographically-associated upwelling, and broad-diffusive upwelling in the ocean interior.
Paramormyrops hopkinsi
"Paramormyrops hopkinsi "(Taverne and Thys van den Audenaerde, 1985) is a species of freshwater electric fish. It was discovered in the Ivindo River in Gabon, in west-Central Africa by Dr. Carl D. Hopkins of Cornell University. It is distributed throughout the Ivindo River basin of Gabon and the Ntem River basin of Cameroon. Described originally as a "Brienomyrus" in 1985 it was transferred to "Paramormyrops" in 2007. The electric discharge has two phases: a head-positive phase followed by a head-negative phase. The mean duration of the EOD is 2.8 ms for females, 2.96 for males. The Fourier transform of the EOD peaks at 536 Hz for females, 468 for males. Both male and female EODs have a head-negative voltage bump about 5 to 6 ms after the main head positive phase (arrows).