Interactive Ocean Light Penetration Simulator

Ocean Light Penetration Simulator

Developed By: Ir. MD Nursyazwi

This interactive module simulates the physical phenomenon of light penetrating the ocean, showing how light intensity decreases with depth due to absorption and scattering. The simulation illustrates the layers of darkness found in the deep sea.

User Guide to the Simulation

This simulator is designed to be an educational tool for exploring the dynamics of light penetration in the ocean. To effectively utilize its features, please follow these instructions:

• Input Manipulation: Navigate to the "Data Input" section and adjust the sliders to manipulate key oceanographic parameters. You can observe how varying conditions influence the light's journey in real time.
• Simulation Control: Use the "Start" button to initiate the simulation. The process can be paused at any time by pressing "Stop" and returned to its initial state with "Reset".
• Visual Interpretation: The "Graphical Simulation" canvas provides a real-time visual representation of how red, green, and blue light rays are absorbed and scattered as they travel downwards. Observe how the overall environment becomes darker with increasing depth.
• Quantitative Analysis: Refer to the "Data Output" section for quantitative metrics such as light intensity at the current depth, scattering events, and the current simulated depth. These values provide a numerical foundation for your qualitative observations.
• Trend Visualization: The "Graphs and Charts" section plots historical data, allowing for the analysis of trends and the relationship between light intensity and depth over time.

Data Input: Oceanographic Parameters

Modify the following parameters to investigate their impact on light penetration and scattering in the ocean.

Water Clarity (Turbidity):

This parameter simulates the clarity of the water. Higher clarity means less scattering from particles, allowing light to travel deeper.

Surface Wave Intensity:

This parameter controls the strength of surface waves. Intense waves scatter light more, creating a less direct penetration and affecting the patterns of light below.

Current Depth (m):

Adjust this to simulate a submersible's descent and observe the changing light intensity at that specific depth.

Graphical Simulation

This canvas visualizes the journey of light into the ocean, reflecting the Quranic description of a deep sea with "darknesses, some of them upon others." Watch as light rays from above are absorbed and scattered, creating stratified layers of darkness. The total darkness line is at 1000m.

Red Light

Green Light

Blue Light

Ocean Water

Submersible

Scattering Particles

Data Output

Real-time quantitative data derived from the simulation, providing insights into the current state of light penetration.

Light Intensity at Current Depth: 100 %

Dissolved Oxygen Level: 100 %

Current Depth: 0 m

Scattering Events: 0

Total Darkness Threshold: 1000 m

Graphs and Charts

This chart visualizes the dynamic relationship between light intensity and depth. The plot shows how light decays exponentially as it travels deeper into the ocean.

Light Intensity

Oxygen Level

Physics of Light Penetration and Scientific Context

The penetration of light into the ocean is governed by two primary physical processes: absorption and scattering. Absorption is the process where light energy is converted into heat or chemical energy by water molecules and dissolved substances. This causes a decrease in light intensity with depth. Scattering occurs when light strikes particles suspended in the water, such as plankton or sediment, causing the light rays to change direction. Both processes contribute to the rapid dimming of light.

The Attenuation of Light

The combined effect of absorption and scattering is known as light attenuation, and its total rate is quantified by the Total Attenuation Coefficient (c). This coefficient is a key parameter in marine optics and can be expressed as the sum of the absorption coefficient (a) and the scattering coefficient (b).

The formula for this is: c = a + b

The attenuation coefficient is not constant; it changes with the wavelength of light and the properties of the water itself. This is why light disappears differently in various ocean environments.

Selective Absorption of the Electromagnetic Spectrum

Water does not absorb all colors of light equally. This is a crucial concept that dictates the visual appearance of the ocean. Red and orange light, which have longer wavelengths and lower energy, are absorbed very quickly, disappearing within the first 10-20 meters. As you go deeper, yellow, green, and finally blue light are attenuated. Blue light, with its short wavelength and high energy, penetrates the deepest, which is why the open ocean appears so blue. In contrast, coastal waters with high concentrations of organic matter and sediment often look green or brown because those components absorb the blue light, leaving the green and yellow wavelengths to scatter back to our eyes.

Types of Scattering

Scattering is the redirection of light by particles in the water. There are two primary types:

• Rayleigh scattering occurs when light hits particles that are much smaller than its wavelength, such as individual water molecules. This process is highly dependent on wavelength, with shorter wavelengths (blue light) scattering more efficiently than longer ones (red light). This phenomenon contributes to the ocean's blue appearance and is the same reason the sky is blue.
• Mie scattering is caused by larger particles, like phytoplankton, bacteria, and inorganic sediments. This type of scattering is less dependent on wavelength and tends to be more forward-facing. It is the dominant form of scattering in turbid coastal waters, contributing to the milky or murky appearance.

Mathematical Proof of Simulation

The simulation's behavior is governed by a simplified form of the Beer-Lambert Law, a fundamental principle in ocean optics. This law models the exponential decay of light intensity as it travels through a medium.

The formula is: I = I₀ × e^-αz

Where:

• I is the light intensity at depth z.
• I₀ is the initial light intensity at the surface.
• e is the base of the natural logarithm (approximately 2.718).
• α is the attenuation coefficient, which represents how quickly light is absorbed and scattered. In this simulation, this value is adjusted by the Water Clarity slider.
• z is the depth.

This equation demonstrates that light intensity decreases exponentially with depth, meaning it dims faster near the surface and slower at deeper levels, but it never truly reaches zero. However, for practical purposes, below 1,000 meters, there is virtually no sunlight.

Oxygen Depletion with Depth

Just as light diminishes, the concentration of dissolved oxygen (O₂) also changes significantly with depth. Oxygen is introduced into the ocean primarily at the surface through two main processes:

• Gas exchange with the atmosphere: Oxygen from the air dissolves into the surface waters.
• Photosynthesis: Marine plants and phytoplankton produce oxygen in the sunlit upper layers.

As depth increases, the light available for photosynthesis rapidly decreases, so oxygen production ceases. At the same time, marine organisms and bacteria continue to consume oxygen for respiration and decomposition of organic matter, leading to a steady decrease in oxygen levels. This process creates a layer known as the Oxygen Minimum Zone (OMZ), often found in the mid-depths, where oxygen concentrations can be extremely low.

The Quranic Perspective on Ocean Darkness

The Quran describes a phenomenon consistent with this scientific understanding in Surah An-Nur (The Light):

أَوْ كَظُلُمَاتٍ فِي بَحْرٍ لُّجِّيٍّ يَغْشَاهُ مَوْجٌ مِّن فَوْقِهِ مَوْجٌ مِّن فَوْقِهِ سَحَابٌ ظُلُمَاتٌ بَعْضُهَا فَوْقَ بَعْضٍ إِذَا أَخْرَجَ يَدَهُ لَمْ يَكَدْ يَرَاهَا وَمَن لَّمْ يَجْعَلِ اللَّهُ لَهُ نُورًا فَمَا لَهُ مِن نُّورٍ

Quran 24:40
"Or [the state of a disbeliever] is like the darkness in a vast, deep sea. It is covered by waves, upon which are waves, upon which are clouds—darknesses, some of them upon others. If he were to take out his hand, he could hardly see it. And to whom Allah has not granted light, he will have no light."

This verse accurately describes a deep sea environment with "darknesses, some of them upon others." Modern oceanography has shown this to be scientifically correct, as the darkness is not uniform but is layered due to different factors. The layers of darkness can be explained as:

• The darkness of the clouds: This is the first layer, which absorbs and scatters some of the sunlight before it even reaches the water's surface.
• The darkness from surface waves: Waves and ripples on the ocean surface cause light to be reflected and scattered, creating another layer of reduced light.
• The darkness from internal waves: Below the surface, between different layers of water density, there are internal waves that further absorb and scatter light.
• The darkness of deep ocean absorption: As light penetrates deeper, it is continuously absorbed by the water itself and by suspended particles, leading to progressively darker layers until no sunlight remains below 1,000 meters.

The verse's description of this multi-layered, stratified darkness aligns perfectly with these modern scientific findings.

References

For further academic inquiry, the following sources provide detailed information on the physics of light in the ocean and its relationship with the Quran:

• Jerlov, N. G. (1976). "Marine Optics."
• Gordon, H. R., & Morel, A. (1983). "Remote Assessment of Ocean Color for Interpretation of Satellite Visible Imagery."
• Al-Daba, M. I. (2018). "The Scientific Miracles of the Quran."
• Aktepe, V. (2021). "Physics of the Sea: From Surface to Hadal Zone."
• Wyatt, J. (2020). "A Theory of Ocean Oxygenation."
• Fischer, D. (2019). "Oxygen Minimum Zones in the Ocean."

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