Final answer:
Low precipitation is a limiting factor for net primary productivity in both terrestrial and aquatic ecosystems by reducing water availability, which can directly restrict plant growth in terrestrial biomes and alter water quality and nutrient distribution in aquatic systems. The correct option is c. Both.
Step-by-step explanation:
When considering the limiting factors of net primary productivity in terrestrial and aquatic ecosystems, we see different environmental challenges that affect plant growth and biomass production. In terrestrial biomes, abiotic factors such as temperature and moisture are paramount. Low precipitation limits plant growth by reducing water availability, which is essential for photosynthesis and maintaining cellular structures. Terrestrial biomes, which include deserts and tundra, exhibit lower primary productivity due to such water restrictions.
In aquatic ecosystems, while temperature can be a factor, other limiting factors like the availability of sunlight and levels of dissolved oxygen and nutrients are more critical. Sunlight penetration affects photosynthetic activity in water, particularly in very deep bodies, shaping different aquatic zones and affecting organism distribution. Low precipitation can affect aquatic biomes as well, with reduced water inputs potentially leading to higher salinity levels and lower nutrient availability.
Given these considerations, it is clear that low precipitation can impose limitations on both terrestrial and aquatic ecosystems by restricting the availability of water directly in terrestrial areas, or by affecting water quality and nutrient levels in aquatic systems. Thus, the correct option is c. Both.