Answer:
Water salinity
Step-by-step explanation:
Water salinity in marine ecosystems is not directly linked to their primary productivity.
Factors that do influence primary productivity in aquatic ecosystems are mainly luminosity and nutrient availability, but temperature also plays an important role for producers (such as algae and phytoplankton).
Luminosity carries sunlight, which is essential for the photosynthesis reactions performed by these organisms. In addition, the greater the incidence of light, the deeper it will reach, and thus more organisms will receive the luminosity to perform photosynthesis.
Nutrient availability also plays a key role in primary production in aquatic ecosystems, as the autotrophic organisms in these ecosystems need them for growth and reproduction, the main nutrients being nitrogen (N) and phosphorus (P).
In addition, water temperature is also a limiting factor for primary productivity in these ecosystems.
In colder waters, oxygen molecules move slower, facilitating their capture by autotrophic beings for photosynthesis, while in warmer waters, there is a greater kinetic energy and therefore oxygen molecules move faster, being harder to capture for photosynthesis reactions.