Gazing out upon the vast expanse of the ocean, one is captivated by the mesmerizing azure hue that stretches as far as the eye can see.

Yet, upon closer inspection, when a handful of seawater is drawn forth and observed, it appears colorless and transparent.

Similarly, lakes often present a verdant green from a distance, yet when scooped up, the water within reveals itself as clear and devoid of color. What then accounts for these striking visual phenomena? Contrary to popular belief, the blue coloration of seawater is not an inherent property of its composition. Rather, it arises from the complex interplay of sunlight with the water's molecules through processes of absorption, reflection, and scattering. Sunlight, comprising a spectrum of colors ranging from red to violet, penetrates the ocean's surface. However, water molecules selectively absorb longer wavelength light, such as red, orange, and yellow, while shorter wavelength light, notably blue and violet, is more readily scattered and reflected.

As a result, the blue light is dispersed throughout the water column, lending the ocean its characteristic hue when viewed from above. Notably, the human eye is particularly sensitive to blue light, enhancing our perception of the ocean's azure splendor. It's a symphony of light and water, where each wavelength plays its part in creating the captivating palette of the sea.

Lakes exhibit a spectrum of colors, with green being a common sight. This verdant hue arises from a combination of factors, including the depth of the lake, its surrounding landscape, and the presence of algae. Unlike the vast depths of the ocean, lakes are often shallower and more constrained. Consequently, they may not absorb as much green light, allowing it to be reflected back to the observer's eye, thus imparting a greenish tint to the water's surface.

The presence of surrounding vegetation, such as trees and grasses, further amplifies the greenish appearance of lakes through reflection. Lakes may harbor significant populations of algae, which contribute to their green coloration. These microscopic organisms, particularly green algae, contain pigments that absorb and reflect light in the green spectrum, further intensifying the water's coloration.

In regions where water pollution is prevalent, lakes may experience eutrophication, resulting in an overabundance of algae. This proliferation of algae can dramatically alter the color of the water, turning it a vibrant green as the algae thrive in nutrient-rich environments.

It's crucial to note that the depth of water bodies, whether oceans or lakes, plays a pivotal role in determining their coloration. The varying depths influence the way light penetrates and interacts with the water, leading to distinct visual perceptions. Thus, while oceans appear blue due to their depth and light-scattering properties, lakes may exhibit a range of colors influenced by their shallower nature and environmental factors.

In essence, the colors of the sea and lakes are a testament to the intricate dance of light and water, shaped by the unique characteristics of each body of water. From the azure expanses of the ocean to the emerald hues of lakes, these natural spectacles remind us of the beauty and complexity of the world around us.