I could try in helping you and if there are any questions that are not answered and you know the answer plese feel free to send them to me, thanks!
You asked for some info. on how a dolphin can show anger, excitement, aggression, etc... for a paper that you were writing. Well, I am willing to share some of my experiences with you......
When dolphins jump out of water is it a type of communication or are they having fun?

I was wondering why when dolphins and whales are in captivity their dorsal fin  doesn't stand up straight like it does in the wild?

Why do some Dolphins have Dorsal fins and some dont?

Do dolphins drink salt water? If so, why do they not get dehydrated?
Why dont dolphins get the bends?

How do dolphins collapseable ribcage work and where may i obtain more information on this subject? 

how do dolphins communicate?

Dolpins have two stomachs one to store food and one to digest it. How long can a Dolphin live without eating and just relying on the food in the reserve stomach?
If I see...
Color or black and white?
What are dolphins habitat like?
can a dolphin kill a shark?
Have they found that dolphins kept in captivity live shorter? Can they get depressed when in captivity?
do dolphins have leaders?
would a dolphins ever hurt another dolphin?
how fast can a dolphin swim?
a calf emerges head or tail first?
If you know the anserws to any of these below, plese click-here>
o Why do dolphins like to jump in front of the boats wakes. Is it play or is there something about the ships that attract this behavior? 

o Do dolphins see in color or in black and white?
What is a dolphins habitat like? 

can a dolphin kill a shark?

o Have they found that dolphins kept in captivity live shorter? Also, can dolphins get depressed if they are kept in captivity, especially if they are confined to a small area?

o Do dolphins have leaders or dominate dolphins in the pod? If so how are they brought to this possition?      
o Why would a dolphin ever hurt another dolphin?

o I seen the show this evening and I noticed they suggest that dolphins migrate using the Earth's magnetic fields. During the show as well they mention some dolphins beach themselves and eventually die. They said they believe this to be a "mass suicide". Is it possible that some dolphins (possibly hereditary, or by species, etc.) somehow follow a certain pattern of the magnetic field each year, or however long of a timeline between migratory periods, and the beaches interfere with this pattern throughout time? Meaning, the dolphins follow the same pattern each time but the beaches evolved in areas that were previously open ocean on the migratory route? 

o are porpoises larger than dolphins? iv'e been telling my grandfather that dolphins are longer than porpoises, am i right?  

o Why is it that dolphins sometimes use other dolphins as "footballs"?

o It is 10 or 12 months of gestation?