This is called Marine Impact and it's Marine's first actual magical skill when it comes to magical girling around. Basically, when she is a magical girl, if she punches something and her hand is glowing blue, she will make whatever she's punching explode.

So yeah, that is basically it for her skill. '^' PUNCH EXPLOSIONS.

Everyone on Heliodor is going to have charm bracelets (VERY SOON, PENDING QUEST TURN IN) to remember the people that have left them because Marine wanted a way to be able to do so. :|b

The bracelets themselves are simple gold bracelets, and the charms so far are these:
Rei: Chopsticks
Fuck: FUCK in blue
Discourse: Gaudy crown
Jet: Pot
Sherlock: Magnifying glass
Zimmy: Garnet skyscraper.