Hey how are all of you doing in the world of 3D?

I have a little problem in my project. I am making a realistic looking earth.

I have placed one bump map on my sphere that represents the bumps of the continents.

But now i want to add another bump map to that same sphere that will represent the waves of the sea.

But how can i use another bump map, because in the atribute editor of my Blinn texture I only see place for one Bumpmap.

Can someone pleace help me with this?

Thanks!