Ark Nova: Marine Worlds; an expansion for Ark Nova; introduces multiple new elements to the game; such as sea animals that each have to be played in new special enclosures that must be built adjacent to water.Roughly half the sea animals are reef dwellers; and whenever you add a reef dweller to your zoo; you trigger the ability of all reef dwellers in your zoo. To deal with the dilution of the deck; naturally caused by adding more cards; all sea cards feature a wave icon; and whenever it is revealed in the display; you discard the first card in the row; then replenish.A new fourth university is available on the association board; and if you take it; you claim one of six special universities from the reserve that feature one research icon and one of six animal icons. When you take this registry; you reveal cards from the top of the deck and keep the first revealed card with an animal icon that matches your chosen university.For each of the five action cards; four alternate versions with a little twist will be available. Players draft action cards at the start of play; replacing two of their standard action cards with these new ones; increasing the asymmetry in the game.New bonus tiles and final scoring cards will also be included.Also the expansion will include alternate wooden markers for the 3 tracks and cute animals to mark the conservation projects you support instead of using your regular player markers.