The contrast between the color of the sandy reef at Sand Key Lighthouse and the deep blue waters of the Florida Keys creates a visually captivating scene:

**1. **Sandy Reef Texture:**
   - The sandy reef beneath the clear waters exhibits a textured surface. The grains of sand create a mosaic pattern, offering a tactile quality to the underwater landscape.

**2. Golden Tones of the Sandy Reef:**
   - Bathed in sunlight, the sandy reef takes on warm golden tones. The sunlight penetrates the water, highlighting the natural color of the sand and creating a beautiful contrast with the surrounding blue hues.

**3. Shallow Turquoise Waters:**
   - The shallows around the sandy reef feature the characteristic turquoise waters of the Florida Keys. The clear, shallow areas allow for the sandy bottom to be visible, creating a seamless transition from golden sands to turquoise shallows.

**4. Gradation of Blue Depths:**
   - As the water deepens around the sandy reef, it transitions into deeper shades of blue. The gradient of blue tones adds depth to the scene, emphasizing the contrast with the lighter tones of the sandy seabed.

**5. Play of Sunlight:**
   - Sunlight penetrates the water, creating a play of light and shadow on the sandy surface. The dancing sunlight adds a dynamic quality to the scene, accentuating the texture of the sandy reef.

**6. Lighthouse Rising Above:**
   - Against this backdrop, Sand Key Lighthouse rises above the sandy reef. The white tower stands out prominently, creating a stark contrast with the warm tones of the sandy seabed and the various shades of blue in the water.

**7. Subtle Coral Accents:**
   - Subtle coral accents, if present on the sandy reef, contribute to the overall color palette. The corals may introduce hints of pink, orange, or other muted tones, further enhancing the visual richness of the underwater environment.

**8. Clarity of the Waters:**
   - The clarity of the waters allows for a clear view of the sandy bottom. Observers can appreciate the details of the sandy reef, creating a sense of transparency and openness in the underwater scene.

**9. Boat Silhouettes:**
   - If boats are present in the scene, their silhouettes may cast shadows on the sandy seabed. The contrast between the man-made structures and the natural environment adds an additional layer of interest to the composition.

**10. Tranquil Atmosphere:**
    - The overall atmosphere is one of tranquility. The serene contrast between the golden sandy reef and the varying shades of blue in the waters contributes to the sense of calmness in this underwater tableau.

In this visual narrative, the interplay of colors between the sandy reef and the blue waters at Sand Key Lighthouse creates a harmonious and captivating underwater landscape in the heart of the Florida Keys.