Os mares cobrem 3/4 da superfície da Terra. Perto do Equador, os mares são quentes; perto do Árctico, são gelados. As correntes fazem com que a temperatura dos mares varie.
As correntes são rios de água que fluem para o mar, em grandes círculos. Os ventos e a rotação da Terra criam as correntes marítimas. Há correntes quentes e frias.
Judging by the context, I take it that `correntes' refers to sea currents. It is said that they are rivers flowing in great circles para o mar. Well, I took a look at a map of currents, and I'd hardly say that they went in circles, but let it be. I wonder what para is supposed to mean. Obviously, it doesn't signify direction, `towards the sea'. Probably it should somehow mean `across the sea', but then I'd expect por instead of para. Prepositions are tricky...
Any help appreciated.