I think your water came out really well. One thing about working from a photo is the values are not always apparent. This is something I saved from a very good artist that was answering the question of why the ocean far away doesn't look lighter in the photo when the law of physics says it should be.
First thing to understand is that photographs don't capture all the information the eye does. They're very good at capturing the shapes of things (unless you're too close, using telephoto or fish eye len's, or manipulating the image afterwards), but not so good at capturing color or values. They get the basics right, but not the fine work since the eye (so far) is much more sensitive at interpreting the information. The other thing the camera is really poor at would at first glance, seem to be its strongest point... everything is captured at an equal amount of detail with an equal amount of interest. The vision, most definitely, doesn't work that way.
In any event... If we think about what happens on land (since our vision is used to this) you'll notice the farther from you something is, a curious thing occurs to it, atmospheric perspective. There are a number of properties to this, a few are...
*Things which are light become darker than if the same object is close to you.
*Things which are dark become lighter than if the same object is close to you.
*The sharpness of things decreases with increasing distance
*The chroma (the strength of color) decreases with distance.
To sum up, the lights and darks move towards a middle value, and the sharpness and color becomes less intense.
Glare of the bright sky interacting with the edge of the sea softens the edge to a large degree. Because the sky is so bright the edge of the sea appears to be getting darker by comparison. In fact, because the edge of the sea is so far from you, it is much like a distant mountain, much lighter than you might at first paint it. Also, as the sea as it moves away towards the horizon has the glare of the horizon interacting with it lightening the edge. It also tends to be less intense blue and shifts a bit in color. The color it shifts towards depends upon the time of day - whether morning, noon, or night, all will have different colors. Also the type of weather and wave height also will have an impact on the color of the sea.
Atmospheric absorption of some of the longer wavelengths of light will normally take out the reds in the colors first, but it depends on the lighting situation.
In any case, that is the reason behind it. It can be used to your advantage when you wish to soften and harden an edge. One of the golden guidelines in art is you never let a hard edge travel any distance for long (the same goes for soft edges)... you normally want produce a variety of edge - some areas a bit softer, then a bit harder, here and there very sharp, and here and there very soft. Figuring out where the soft areas should be or the hard areas should be on the edge of something is where the "art" of it starts to develop. This variety is interesting to the eye and makes the picture more vibrant and human... rather than a transcription by a meat camera.