There are a few reasons why there are more living organisms in warm water.
1) Oxygen solubility: The solubility of oxygen in water decreases as temperature increases. This means that cold water can hold more dissolved oxygen than warm water. However, the metabolic rate of organisms also increases with temperature, meaning that they require more oxygen. As a result, warm water can support a greater density of organisms than cold water.
2) Diversity of habitats: Warm water environments provide a wider range of habitats for organisms. This includes coral reefs, mangrove swamps, and seagrass beds. These habitats provide food, shelter, and breeding grounds for a variety of animals and plants.
3) Sunlight: Sunlight is essential for photosynthesis, which is the process by which plants convert sunlight into energy. Warm water environments receive more sunlight than cold water environments, allowing plants to grow more quickly and produce more food. This increased food production supports a greater diversity of organisms.
Overall, the combination of factors such as oxygen solubility, habitat diversity, and sunlight makes warm water environments more conducive to life. As a result, there are more living organisms in warm water than in cold water.