Chapter 1, Problem 1CF

Summary Introduction

To describe:

The reason that climate scientists never realized that microbes actually caused nucleation of water droplets in clouds.

Concept introduction:

Bacteria are omnipresent. They are present in unimaginable environmental conditions. One such bacterium is Pseudomonas syringae which resides in clouds, inducing precipitation. These bacteria are found in the first stages of a hailstone, and they act as nucleating particles that aggregate water droplets. These aggregations of water droplets fall on earth as rain.

Explanation of Solution

Climate scientists never realized that microbes actually caused nucleation of water droplets in clouds because they might not have known that the microbes are too widely spread in the clouds in first place. While looking for nucleators in cloud samples, climate scientists must have used the filters that only trap fine dust particles, and not smaller particles, including microbial sized particles.

Conclusion

Climate scientists had never realized that microbes actually caused nucleation of water droplets in clouds because they must have filtered only the fine dust particles, and not much smaller microbial sized particles while looking for nucleators.

Summary Introduction

To describe:

The ways in which P. syringae can make it rain in warm temperatures.

Concept introduction:

Pseudomonas syringae resides in clouds are found in the first stages of a hailstone, where they act as nucleating particles that aggregate water droplets contributing to potential rain. There are other nucleators of ice other than P. syringae, including fungi, algae, diatoms, and other bacteria. However, only P. syringae can cause precipitation at much warmer temperatures.

Explanation of Solution

Pseudomonas syringae is the nucleator of ice but it can also carry out this process at a much warmer temperature to cause rain. It can do so as it contains a protein structure which serves as a site of attachment for freely moving water molecules. When the vapors of water get attached to these bacteria, along with other water molecules, it freezes and falls downwards to the Earth.

Conclusion

P. syringae can make it rain in warm temperatures as they contain a protein structure which serves as a site of attachment for freely moving water molecules where vapors get attached and freeze to fall on Earth as rain.