Aquatic ecosystem primary productivity is most dependent on factors like nutrient availability, sunlight, and temperature. Nutrient-rich waters, especially those with ample nitrogen and phosphorus, support higher primary productivity.

The region with the highest primary productivity in aquatic ecosystems is often the coastal zone, where nutrient-rich waters from rivers and upwelling support abundant plant and algal growth. Coral reefs and estuaries are also known for their high productivity due to nutrient inputs and sunlight availability.

Dr Likhon Chandra Roy thank you for your contribution to the discussion

Aquatic primary production is dependent on many factors like salinity of water, availability of light in the different zones of the ocean, the source of energy for photosynthetic organisms, and availability of mineral nutrients, etc. Primary production in the aquatic ecosystem starts with the synthesis of organic compounds from the inorganic constituents of water by the activity of plants in the presence of sunlight. Primary productivity depends upon plant species of the area, their photosynthetic capacity, and availability of nutrients, solar radiations, precipitation, soil type and a number of other environmental factors. Temperature, sunlight, oxygen content, nutrition availability, and salinity are the main limiting factors in an aquatic ecosystem. In terrestrial ecosystems Tropical rain-forests show the highest productivity. In aquatic ecosystems, coral reefs have the highest productivity. The productivity of aquatic primary producers depends on a number of biotic and abiotic factors, such as pH, CO2 concentration, temperature, nutrient availability, solar UV and PAR irradiances, mixing frequency as well as herbivore pressure and presence of viruses, among others. Primary Productivity refers to the generation of biomass from autotrophic organisms such as plants. Photosynthesis is the primary tool for the creation of organic material from inorganic compounds such as carbon dioxide and water. Primary Productivity refers to the generation of biomass from autotrophic organisms such as plants. Photosynthesis is the primary tool for the creation of organic material from inorganic compounds such as carbon dioxide and water. The most productive aquatic ecosystems are shallow-water marine ecosystems where light is ample and autotrophs are multicellular with complex structures or associations. There is generally greater productivity near the coasts than in the open ocean. Coastal areas are hotspots for primary producers who require higher sunlight conditions, nutrient sediment, and organic inputs, and protection from large tidal events in order to be productive. Primary productivity in an ecosystem refers to the accumulation of energy in the form of biomass. Coral reefs have the highest productivity in aquatic ecosystems. In terrestrial ecosystems, tropical rainforests have the highest productivity. The productivity of aquatic systems has been given two meanings in the literature: either the transfer of matter or energy through the food web, or the quantity of fish that may be captured in a sustainable way per unit of time. A number of short-cuts may be used to estimate the sustainable fish catch. The productivity of aquatic systems has been given two meanings in the literature: either the transfer of matter or energy through the food web, or the quantity of fish that may be captured in a sustainable way per unit of time. A number of short-cuts may be used to estimate the sustainable fish catch. The annual net primary productivity of the whole biosphere is approximately 170 billion tons (bt). Out of this, terrestrial ecosystem contributes 115 billion tons while the rest 55 billion tons is contributed by ocean ecosystems. Due to the mixing of a natural flowing watercourse, typically freshwater, and the saline content of water, estuaries are highly active as they are nutrient traps. The tidal mouth of this inland watercourse is an estuary.