The order of productivity in ecosystems generally follows this sequence from highest to lowest:

As for areas of the ocean with the highest levels of productivity, these are often associated with specific oceanographic features that enhance nutrient availability. Some of the most productive areas in the ocean include:

Overall, ocean productivity is influenced by factors like nutrient availability, sunlight, and water temperature, and various oceanographic features play a role in creating areas of high productivity.

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

Salt marshes and mangroves have one of the highest productivity of 3300- 6000 grams carbon per square meter per year. So the correct sequence of ecosystem in the order decreasing productivity is: Mangroves > Grasslands > Lakes > Oceans. So the sequence of ecosystems in the order of decreasing productivity is Ocean>mangroves> lakes>grasslands. Ocean or marine ecosystems usually have a large biodiversity. The highest net primary productivity in terrestrial environments occurs in swamps and marshes and tropical rainforests; the lowest occurs in deserts. Oceans contain lots of nutrients but they have no sufficient sunlight reaching in the deep areas, therefore, oceans have the least productivity among all ecosystems. The average productivity of an ocean ecosystem is about 50 grams of carbon per square meter per year. In the aquatic ecosystem, coral reefs show the highest gross primary productivity. Large numbers of aquatic phototrophs and phytoplankton contribute to the productivity of the ecosystem. Mangroves, grasslands, lakes, oceans are the percentage of energy that enters an ecosystem in the form of biomass at a particular trophic level is termed as Productivity of the Ecosystem. Although they occupy less than two percent of the oceans, the coastal upwelling areas in the eastern parts of the Pacific and Atlantic Ocean are among the biologically most productive marine areas worldwide. The proximity to land and its nutrient sources, the interception of sinking organic matter by the shallow seafloor, and the propensity for coastal upwelling all result in highly productive ecosystems.Estuaries, swamps and marshes, tropical rain forests, and temperate rain forests. What ecosystems have the least amount of productivity per unit area? Tundras, the open ocean, desert scrubs, and the extreme desert. The annual net primary productivity of the entire biosphere is around 170 billion tonnes of the dry weight of organic matter. The annual net primary productivity of the oceans is around 55 billion tonnes and that of land is around 115 billion tonnes. 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. This is the portion that is available to be consumed by the primary consumers and passed up the food chain. In terrestrial ecosystems, primary productivity is highest in warm, wet places with plenty of sunlight, like tropical forest regions. In contrast, deserts have the lowest primary productivity. Primary productivity in the tropical zone is limited not by sunlight it receives, but because a thick thermocline prevents nutrients from moving up in to the surface in the photic zone. Primary productivity in the polar zones are most intense in the summer months when both sunlight and nutrients are available. Some highly productive areas include the California coast (200-300 g C/m2/year), the Southern Ocean (200-400 g C/m2/year), and the coast of Peru (200-400 g C/m2/year), all regions with significant upwelling . The central ocean, by contrast, produces less than 50 g C/m2/year.