Surge: Aquaman can use Charge. When Aquaman occupies water terrain, modify his speed value by +2.

King of the Seven Seas: When Aquaman occupies water terrain, he can use Invulnerability. When Aquaman does not occupy water terrain, he can use Toughness.

Errata
Aquaman‘s character card should list the point value as 70 points.

What happens if Aquaman occupies water terrain, but then my opponent TKs an object under Aquaman. Is he now occupying water terrain or hindering terrain?
He occupies both. He is still in water, so his special powers will work just fine, but since he is also in hindering terrain he can modify his defense against ranged attacks, he will halve his speed value, and all the other effects associated with hindering terrain.