What Is Productivity Of The Ocean’S Surface?

Coastal waters are more productive than the central ocean due to two main reasons: first, runoff from land often contains a high abundance of nutrients which get deposited in coastal waters and stimulate production. Second, the shallower bottom along the continental shelf can trap nutrients and prevent them from sinking to greater depths. Productivity fuels life in the ocean, drives its chemical cycles, and lowers atmospheric carbon dioxide. Nutrient uptake and export interact with circulation to yield distinct ocean regimes.

Ocean productivity largely refers to the production of organic matter by phytoplankton, plants suspended in the ocean, most of which are single-celled. Global averages for ocean surface primary production are about 75-150 g C/m2 /yr. Some highly productive areas include the California coast (200-300 g C/m2 /year), the Southern Ocean (200-400 g C/m 2 /year), and the Pacific Ocean. The productivity of the entire ocean is estimated to be approximately 16 × 10 10 tons of carbon per year, which is about eight times that of the land.

The present report examines the nature of the species associations that carry the productivity and bottom water oxygen concentration signals. Productivity fuels life in the ocean, drives its chemical cycles, and lowers atmospheric carbon dioxide. Nutrient uptake and export interact with circulation to yield distinct ocean regimes.

Reconstructions of ocean productivity using sediment records typically involve the accumulation of biogenic matter in the sea floor. Ocean productivity (also known as marine productivity) refers to the primary production of single-celled phytoplankton suspended in the ocean.

What is the definition of ocean productivity?

Ocean productivity is primarily the production of organic matter by phytoplankton, which are photoautotrophs that convert inorganic to organic carbon. These plants supply this organic carbon to diverse heterotrophs, such as bacteria, zooplankton, nekton, and benthos. Ocean productivity is characterized by various nested cycles of carbon, including gross primary production (GPP), net primary production (NPP), secondary production (SP), and net ecosystem production (NEP).

GPP refers to the total rate of organic carbon production by autotrophs, while respiration refers to the energy-yielding oxidation of organic carbon back to carbon dioxide. Net primary production (NPP) is GPP minus the autotrophs’ own rate of respiration, indicating the rate at which the full metabolism of phytoplankton produces biomass. Secondary production (SP) typically refers to the growth rate of heterotrophic biomass, with only a small fraction of organic matter used for growth. Fisheries rely on SP and depend on both NPP and the efficiency of organic matter transfer up the foodweb.

Net ecosystem production (NEP) is GPP minus respiration by all organisms in the ecosystem, with the value depending on the boundaries defined for the ecosystem. For example, NEP for the entire ocean is roughly equivalent to the slow burial of organic matter in sediments minus the rate of organic matter entering from the continents.

Productivity in the surface ocean is connected to nutrient cycling, with the blue cycle representing net ecosystem production (NEP), the red cycle representing the fate of organic matter produced in the surface ocean, and the green cycle representing internal respiration of phytoplankton. These nested cycles result in gross primary production (GPP) representing gross photosynthesis and net primary production (NPP) representing phytoplankton biomass production, which forms the basis of the food web. While new nutrient supply and export production are ultimately linked by mass balance, there may be imbalances on small scales of space and time, allowing for brief accumulations of biomass.

Why is there greater productivity below surface of ocean?

In deep water, nutrients are more abundant due to the lack of producers to utilize them at depth. For phytoplankton, productivity depends on the availability of light and nutrients, as light is vital for photosynthesis. They are limited to the uppermost layers of the ocean where light is abundant enough to sustain the reaction. As depth increases, light intensity decreases until there reaches a depth where photosynthesis can no longer occur. This region is called the photic or euphotic zone, which extends down to about 200 meters.

Phytoplankton also respire, consuming some of the organic compounds they produce. Rates of respiration are not light dependent, and respiration occurs at all depths and light levels. As depth increases, the rate of photosynthesis declines as light is diminished, until a point is reached where the rate of photosynthesis equals the respiration rate. This depth is the compensation depth, marking the lower level of the photic zone and marking the depth where net primary production ends.

What factors affect ocean productivity and how?

Ocean productivity is the primary production of single-celled phytoplankton suspended in the ocean, which supply organic matter to heterotrophs. Primary productivity is limited by nutrient and light availability, with colder, nutrient-rich waters trapped below warmer, sunlit water. The thermocline, which separates nutrient-rich waters from the photic zone, limits primary productivity. Open oceans have a lower rate of productivity compared to coastal zones and areas near upwellings. Most organic matter is respired back into dissolved inorganic forms, available for reuse by phytoplankton.

What is the reason for low productivity of the ocean than land?

The Earth is composed of 70% ocean and 30% land. Sunlight is a major limiting factor in oceans, as it decreases the intensity of light, reducing the photosynthetic rate. This decrease in photosynthesis can hinder the development of plants and animals in aquatic environments. Phytoplanktons carry out the maximum primary production in oceans, while land is rich in mineral deposition, causing scarce nutrients and minerals. Small, floating autotrophic plants in oceans are the major producers, but their productivity is low due to their less vascular nature.

Terrestrial plants have developed advanced structures to enhance their photosynthesis capacity. The productivity of land is 170 billion tons, while the ocean’s productivity is only 55 billion tons. Marine waters offer maximum productivity through coral reefs, sea grasses, and brown algal beds. Cool waters also contain dense forests formed by kelps in the sublittoral zone of rocky coasts.

What is productivity zone?

Productivity zones are areas in a field with varying yield histories, with high productivity zones having the highest harvest for several seasons. There are also low and moderate productivity zones, which can be stable or unstable. They can be used for fertilizer application, sowing, and soil sampling. To define productivity zones, use the OneSoil web app’s Fertilizers or Sowing rate tabs and select your field on the map. The app will process NDVI data for the last four years and display a productivity zone map. To conduct soil analysis, use the map to take soil samples for each productivity zone.

What is the relationship between sea surface temperature and primary productivity?

Warmer temperatures negatively impact phytoplankton growth due to the less mixing between surface waters and deeper, more nutrient-rich water. As nutrients become scarce at the surface, where phytoplankton grow, productivity declines. This effect is most evident in the permanently stratified ocean, where there is a distinct difference in density between warmer, fresher water at the surface and colder, saltier water deeper down.

As surface water warms, stratification becomes more pronounced, suppressing mixing further. As a result, nutrient transfer from deeper water to surface waters declines, and phytoplankton productivity also declines.

Rising levels of carbon dioxide in the atmosphere play a significant role in global warming. As the climate warms, phytoplankton growth rates decrease, and the amount of carbon dioxide these ocean plants consume, allowing carbon dioxide to accumulate more rapidly in the atmosphere, resulting in more warming.

What is ocean zones productivity?

Primary productivity in oceanic waters varies geographically and seasonally, with coastal waters being more productive due to the high abundance of nutrients deposited in runoff from land and the shallower bottom along the continental shelf. The central ocean generally has very low primary production, as these areas are far removed from terrestrial sources of nutrients and the great depth prevents deep nutrients from returning to the surface. Global averages for ocean surface primary production are about 75-150 g C/m 2 /yr.

Regional and seasonal changes in primary production are due to the availability of light and the amount of nutrients provided by water mixing above the thermocline. In tropical regions, sunlight is plentiful throughout the year, making light a limiting factor. Surface water is always warm and there is a pronounced thermocline, leading to highly stratified water that prevents nutrient-rich bottom water from reaching the surface. As a result, productivity in tropical water is always nutrient-limited and low throughout the year. The water is very clear, as is the case with water in the central ocean.

What is the most productivity in the ocean?

The coastal upwelling areas in the eastern Pacific and Atlantic Ocean, which occupy less than 2% of the oceans, are among the most biologically productive marine areas globally. These areas support a large biodiversity and provide 20% of the world’s fish harvest, posing significant societal and economic importance for neighboring countries and the global food supply. However, the Federal Ministry of Education and Research is supporting three joint projects under the theme “Importance of climate change in coastal upwelling areas” to investigate these areas in the north- and south-eastern Atlantic and the south-eastern Pacific.

The projects, which will receive funding of 8. 7 million euros over three years, aim to better understand the sensitivities of these areas to climate change and identify possible consequences at an early stage. The coastal upwelling areas are characterized by major ocean currents flowing parallel to the coast, such as the Benguela Current in the south-eastern Atlantic, the Canary Current in the north-eastern Atlantic, and the Humboldt Current in the south-eastern Pacific.

Why is productivity greatest near the ocean’s surface?

The penetration of sunlight into the upper layers of the oceanic water column stimulates the process of photosynthesis, while upwelling facilitates the transfer of nutrients to the surface.

Which layer of the ocean is the most productive?

The photic zone, which extends from a few meters to 150 meters in depth, represents the primary productivity area for marine life. It is estimated that approximately 90% of all marine life resides in this upper zone.

Which oceanic zone is most productive zone?

The continental shelf is defined as the seabed extending from the shore to the edge of the continental slope. It is surrounded by shallow shelf seas and gulfs, which contribute to its status as a highly productive ocean region.