GPA 3.0, enough for Grad School?

[NitromanseR]

Hi everyone,

My name is Peter and I study in Greece (I am a US Citizen, I was just born n NY). I study marine sciences at the environmental sciences school in Greece. Sooner or later I will graduate so, I have started thinking about my future. I would like to do a PhD in something like environmental sciences/environmental engineering. When I 'll grad my GPA will be B or hopefully B+. The past 2 summers I did internship at the University of Michigan and hopefully I will go the coming summer too, my internship was at the environmental engineering. I also think I will have pretty strong recommendation letters. So, I would like to know in which universities I do have some chances to do my PhD. I would love to go to U of Michigan but it maybe be a bit tough for me, cause it is a very competitive school. So, do I have some chances at the top 30-50 or a lot of chances at the 50-100?

thanks everyone in advance,

Peter