The black and white was undoubtedly an odd innovation for kids perusing the stands in the summer of '63. In the story, it doesn't make much sense, though.
Geez, this guy cameos in more WF stories than I remembered! I'm surprised he never got his own backup series: PROFESSOR NICHOLS, TIME DETECTIVE.
Marvel's version of Thor had been around for a full year at this point so it seems a little odd for this particular DC version to show up. I'm betting editor Schiff hadn't been paying one lick of attention to what the rival company--and particularly his own old legal opponent (over SKY MASTERS) Jack Kirby--had been doing.
Aquaman stories didn't tend to be particularly colorful but this one, drawn beautifully by Ramona Fradon, certainly is colorful and fun.