This book reminded me a lot of The Swarm. I'm not saying this is derivative, or suggesting plagiarism. I just think if you enjoyed reading one, you'd probably enjoy the other. I did enjoy this book quite a bit, but it left me with a lot of questions. First, the positives. This book grabs you right from the beginning and it is tough to put down. Even though it is sci-fi, none of the explanations that involve math and/or science are too complicated for even a math/science dummy like me to understand. There was a lot of good action, and I could easily see this being a movie. I also liked that even though there was just a hint of a possible romance, it didn't take over the plot of the book.
When I finished the book, I had a lot of questions. The author points the reader to his web site for a Q&A. While a lot of my questions were answered under the FAQ section, I posit that if all his readers are asking the same questions, doesn't that point to plot holes that should be addressed in the book? And I had more questions. Spoilers follow, so read at your own risk. How does Caesare live, go through the portal and come back, all without Clay knowing or seeing him until the end? Was the blue light that stopped the helicopters from the aliens? If so, how did they do that and how did they know they needed to? Why was Palin's son pointing the transporter box at the computers? Was he just trying to get himself out of there? Why didn't the computer guy (Borger? Can't remember his name...) tell anyone that the subs were destroyed by their own torpedoes instead of letting everyone think the aliens attacked them? Did the aliens have some kind of healing abilities that we don't have? Did the dolphin translator work on all dolphins? The book made it seem like it would only work with Dirk and Sally but that doesn't make sense. When Alison was transmitting the danger message over and over, why did no other dolphins swim over to see what was going on? The ocean is full of dolphins and the book makes it seem like they are superior beings with a lot of curiosity. That bothered me too. Dolphins are known to be rapists and murderers, so I didn't like Dirk and Sally getting all judge-y. And as a marine biologist, Alison should have known that, so I don't know why she put dolphins on such a pedestal. My final question is why did the female characters have to be so overly emotional and almost unlikable, and blow up at their male superiors, while the male characters remained cool and calm, even when faced with almost certain death?
I really did like this book, but I think the author could benefit from a professional editor. An editor would make sure the reader wasn't left with so many questions. The copy-editing could have been better, though sadly, I've seen much worse. A few notes for the author as far as that goes: first, directions do not need to be capitalized (north, south, etc.). Second, it's utmost, not upmost. And finally, who's means who is. The word you wanted was whose. Please pick up a copy of Strunk & White's Elements of Style and think about getting an editor. I do think you have a lot of talent that just needs some fine-tuning.