Tropical rainforests are often considered to have the highest rates of net primary productivity (NPP) among terrestrial ecosystems. Net primary productivity refers to the amount of energy captured by plants through photosynthesis minus the energy they expend in respiration. Tropical rainforests have warm temperatures, abundant sunlight, and high levels of precipitation, which create ideal conditions for rapid plant growth and high rates of NPP.

As for the ocean zone with high productivity and abundant organisms, the Euphotic Zone stands out. The euphotic zone is the upper layer of the ocean where sufficient sunlight penetrates, allowing for photosynthesis to occur. This zone is well-illuminated, and primary producers like phytoplankton can thrive due to the availability of sunlight and nutrients. Phytoplankton form the base of the marine food chain and support a wide range of marine organisms, including zooplankton, fish, and larger marine predators.

The euphotic zone is particularly important in supporting marine ecosystems and contributes significantly to global primary productivity. Nutrients from deeper ocean layers are brought up through processes like upwelling, enhancing the productivity of the euphotic zone. This zone is essential for the health and sustainability of marine life and plays a crucial role in Earth's carbon and nutrient cycles.

Dr Gaurav H Tandon thank you for your contribution to the discussion

Tropical rainforests, swamps and marshes, and algae beds and reefs are ecosystems with the highest Net primary productivity. While open ocean and desert ecosystems have the lowest NPP.The rate at which energy or organic matter stored by producers in their bodies per unit area per unit time is called the net primary productivity of an ecosystem. The productivity of tropical rainforests is the highest. The rate at which energy or organic matter stored by producers in their bodies per unit area per unit time is net primary productivity of an ecosystem. The productivity of tropical rainforests is the highest. 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 neritic zone is the region of shallow water (200 meters depth) above the continental shelf where light penetrates to the sea floor. Due to the abundant supply of sunlight and nutrients in this zone, it is the most productive ocean zone supporting the vast majority of marine life. The highest net primary productivity in terrestrial environments occurs in swamps and marshes and tropical rainforests; the lowest occurs in deserts. The world's ecosystems vary tremendously in productivity, in terms of NPP per unit area; the most productive systems are estuaries, swamps and marshes, tropical rain forests, and temperate rain forests. The regions of high ecological productivity represented by shallow water areas, moist forest, alluvial plains and regions of intensive farming. The regions of low ecological productivity represented by arctic snow-covered wastelands deserts and Deep Ocean areas. NPP of Tropical rainforests is the highest this is because Tropical rainforest has abundant rainfall, warm temperature, abundant sunlight and rich diversity of species. The neritic zone is the most productive ocean region, as it supports an abundance of living organisms. It has been estimated that 90% of the world's fish and shellfish harvest comes from the neritic zone. Of the open ocean zones, most life is found in the epipelagic zone. This is where light is able to penetrate the ocean, allowing for photosynthetic processes to take place. It extends roughly 200m or 650 feet below the surface. This zone may also be known as the euphoric zone, the sunlight zone, or the photic zone. Most net primary production in the ocean takes place in the epipelagic zone, primarily in the neritic zone near the shore. Net primary production is the greatest in this region as it's the upper layer of the ocean and therefore receives the most sunlight. Continental shelf is the seabed from the shore to the edge of the continental slope, covered by relatively shallow seas and gulfs. Generally, it is one of the most productive parts of the ocean. Many benthic, coastal animals have evolved larval stages which swim for a time in the water. The coastal zone makes up only 10% of the oceanic environment, but it contains 90% of all marine species. Coastal zones are the most nutrient-rich life zones of the oceans. So it should not be a surprise that about 90% of marine life is found in the Epipelagic Zone. The Epipelagic Zone is also where water temperature can vary the most across the globe.