I have gums with black marks..is that serious?

Gums black: It could be an amalgam tattoo, to be sure see your dentist for an exam.

Yes, it could be: Black is not a normal color for gum tissue. It may indicate infection or worse. Go see a dentist asap and get your gums checked.

No, pigmentation: Very common with people of african descent.

NO: Melanin pigment on the gum in the attached gingiva is normal, although now you can remove them with the use of laser (similar to removing a tattoo).

All great answers!: All my colleagues are correct. Obviously there are many possibilities. As we cannot actually see what you see, the only way to know what it is to see your dentist. Sooner is better than later, even if it is nothing, just to put your mind at ease.