Also, here is what I have learned from emailing the schools.
OSU (COAS): They are making decisions now, still can't get an answer on when they will be sent out.
URI (GSO): Rolling admissions, no word on when they will be sent out.
UW (Oceanography): They are trying to make all decisions by March 5th.
I think you will definately get in somewhere and be able to persue your dream in marine bio. I would recommend just taking a few additional classes somewhere so your GPA is >= 3.0, just so you make the cutoffs that some schools employ.
I would highly recommend looking at Moss Landing Marine Laboratories. Fantastic and well known school focusing on marine science research and fieldwork. You can apply through a number of CA state schools. I got my M.S there and found it to be an amazing program. I got in with a 3.2 GPA, + strong work experience and a undergrad pub. PM if you have any questions about the program or faculty.
I would also continue looking for RA jobs in marine bio. Lots of opportunities posted daily here.
I think if you can get a year or two of research experience, maybe be a coauthor on a publication you will be competative.
I know that if you are a NOAA fisheries observer for 6 months, they have a scholarship you can use for grad school. My friend just went this route and ended up at OSU. This can make your app much more competative. Plus the observer postiion pays very well, you could do that, save some money up and then apply.
If your in your early twenties, you will really regret declining your offer later.
I would accept, and see how the first semester goes. You have nothing to lose and everything to gain by giving it 6 months.
You can always just finish up with a MS if the PhD is not for you.
You need more perspective to see if this is just a temporary SLUMP or RUT that your in regarding science. I get in rut lots of times with my passions such as playing music and feel that I hate it. But if I wait it out, I always return and enjoy it again.
The passion may return tenfold in the right environment or with some ethusiasm provided by your peers.
cost of living is very high, especially if you want to live in a safe area that is nice.
Near SF or LA you can expect to pay $1200 for a one bed apartment. Maybe 600-800 for an OK room. Where I live in Central CA it is even higher.
I got into UO for next fall and I can't believe how affordable it is there, rents seem around 600-800 for a 2 bed place. Pretty excited about the possibility of stretching my stipend a bit more up there.