Which biome has the lowest net primary productivity (NPP)?

The biome that exhibits the lowest net primary productivity (NPP) is the desert. This is primarily due to the extreme environmental conditions that characterize deserts, including low precipitation, high evaporation rates, and extreme temperature fluctuations. These factors limit the growth and survival of vegetation, which in turn restricts the overall amount of biomass that can be produced through photosynthesis.

In desert biomes, limited water availability means that plants often have to adapt to survive, leading to sparse vegetation and low overall productivity. Despite being home to some resilient species, the overall biomass produced in deserts is much lower compared to more productive biomes like tropical rainforests or grasslands, where conditions such as ample sunlight, moisture, and nutrients foster greater plant growth.

The other biomes, including grasslands, tropical rainforests, and tundras, have higher levels of productivity due to various factors such as more consistent rainfall, favorable temperatures, and the richness of soil nutrients, allowing them to support more diverse and abundant plant life.