Microscopic sea organisms don't directly form natural gas. Instead, they play a crucial role in a much longer and complex process called organic matter decomposition and diagenesis.

Here's a breakdown of how it works:

1. Plankton and Algae: Microscopic organisms like plankton and algae are the primary producers in the ocean. They photosynthesize and absorb carbon dioxide, producing organic matter.

2. Death and Sedimentation: When these organisms die, they sink to the ocean floor, becoming part of the sediment layer.

3. Decomposition: Bacteria and other microorganisms in the sediment decompose the organic matter, breaking it down into simpler compounds like methane and hydrogen sulfide. This process, called biogenic methane formation, is one way methane (a primary component of natural gas) can be produced.

4. Burial and Diagenesis: As more sediment accumulates on top, the organic matter gets buried deeper. The pressure and heat increase, leading to further decomposition and transformation of the organic matter. This process, called diagenesis, involves complex chemical reactions that can convert organic matter into hydrocarbons, including natural gas.

5. Hydrocarbon Migration: Over millions of years, the natural gas can migrate through porous rock formations until it gets trapped in impermeable rock layers, forming a natural gas reservoir.

So, while microscopic sea organisms don't directly form natural gas, they contribute the organic matter that serves as the raw material for its formation. This process takes millions of years and involves complex geological and biological interactions.