state the pressure distribution of an isothermal atmosphere....?

Assuming they're allowing for a gradient of density based on gravity, for short distances it will seem linear, but over long distances the density of air increases, meaning there is more air above you pushing down. This will probably be a quadratic or exponential growth rate . (I don't know the equation offhand, but you probably have one handy in notes or a textbook).

The ocean would be somewhat similar, but it will seem MUCH more linear and there will be a sort of "density saturation" where the force required to increase the density of liquid water becomes very high and the density stops growing significantly. The growth of pressure through increase in depth will be mostly linear, based on the size of the column of water pressing down, (and potentially that of the air above pressing on the water as well).

Pressure is hard to be control, but if you have the determination and have the impeccable attitudes towards pressure, I'm sure everyone are able to function well under pressure.