Why Does The Pacific Have Greater Primary Production Than The Atlantic?

What’s the difference between the Pacific and the Atlantic Ocean?

The Pacific Ocean, which borders San Diego, is the largest and deepest ocean in the world, covering over 63 million square miles. The Atlantic Ocean, on the other hand, is the second-largest, covering 41 million square miles. The Pacific stretches from the west coast of the Americas to Asia and Australia, while the Atlantic lies between the east coast of the Americas and Europe and Africa. Water temperature and climate differ significantly for surfers, with the Pacific Ocean off the coast of San Diego having cooler waters due to the California Current, while the Atlantic Ocean, particularly along the eastern United States, is warmer due to the Gulf Stream. Wave conditions are crucial for surfers, with the Pacific Ocean being renowned for its consistent and powerful waves.

Why is primary productivity low in tropical oceans?

Primary production in tropical regions is influenced by the availability of light and the amount of nutrients provided by water mixing above the thermocline. In tropical regions, sunlight is abundant throughout the year, leading to nutrient-limited productivity. The surface water is always warm and has a pronounced thermocline, preventing nutrient-rich bottom water from reaching the surface. This results in clear water, similar to central ocean water.

At the poles, the water is uniformly cold at all depths, allowing mixing to occur year-round, distributing nutrients throughout the water column. However, polar regions may experience months with little or no light during winter, causing variation in seasonal productivity. In winter, mixing occurs and nutrients are abundant, but there is no light, so productivity is low. By late spring, sunlight returns, and a spring/summer bloom of phytoplankton occurs. By late summer, nutrients have been depleted, and zooplankton graze on the phytoplankton, causing the bloom to decline.

In temperate regions, seasonal variation in the depth and intensity of the thermocline is more pronounced in winter months. This winter mixing creates nutrient-rich water during the winter but limits productivity. When light levels increase in spring, a spring bloom of productivity occurs. However, by late summer, the nutrients have been depleted, and the summer thermocline prevents further mixing, resulting in productivity decline.

In autumn, cooler temperatures weaken the thermocline, and storms cause a deeper mixed layer to form, bringing nutrients back to the surface. A smaller autumn bloom occurs, but it is short-lived as light declines throughout the autumn and into winter.

Why do coastal regions tend to have more primary productivity?

Productivity in coastal ecosystems is often distinct from that of the open ocean due to shallow seafloor, sunlight penetration, and the interception of sinking organic matter by the seabed. This results in highly productive ecosystems, with proximity to land and its nutrient sources, the interception of sinking organic matter by the shallow seafloor, and the propensity for coastal upwelling all contributing to productivity.

Phytoplankton require a suite of chemicals, which are typically identified as “nutrients”. Calcium is an example of an element rapidly assimilated by some plankton for production of calcium carbonate “hard parts”. Dissolved inorganic carbon, which is the feedstock for organic carbon production by photosynthesis, is also abundant and not typically listed among the nutrients. However, its acidic form dissolved CO2 is often at adequate low concentrations to affect the growth of at least some phytoplankton.

Broadly important nutrients include nitrogen (N), phosphorus (P), iron (Fe), and silicon (Si). There appear to be relatively uniform requirements for N and P among phytoplankton. The Redfield ratios, found in the early 1900s, show that plankton build their biomass with C:N:P stoichiometric ratios of ~106:16:1. Iron’s scarcity often limits or affects productivity in the open ocean, especially those regions where high-N and -P deep water is brought rapidly to the surface.

Silicon availability is a major factor in the broader ecology and biogeochemistry of surface waters due to the dominance of diatoms in Si-bearing waters and the tendency of diatom-associated organic matter to sink out of the surface ocean.

What regions of the ocean are most productive Why?

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, thereby having significant societal and economic importance for neighboring countries and the global food supply. However, the potential for these areas to continue to serve their function if oceans continue to warm, acidify, and lose oxygen, and the wind systems driving upwelling change is uncertain.

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 will receive a total funding of 8. 7 million euros over three years. 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.

Which area of the ocean has the highest level of primary production?

The majority of net primary production in the ocean takes place in the epipelagic zone, with the greatest concentrations occurring in the neritic zone in proximity to the shoreline.

Why does the Pacific spread faster than the Atlantic?

Faster spreading ridges like the northern and southern East Pacific Rise are hotter, causing more magma beneath the ridge axis and more volcanic eruptions. This allows the plate under the ridge crest to respond more fluidly to the divergent spreading process, resulting in ridge spreading more like hot taffy being pulled apart. Slow spreading ridges like the Mid-Atlantic Ridge have large, wide rift valleys and rugged terrain at the ridge crest, with relief of up to a thousand meters.

Why is there no primary productivity in most of the deep ocean?

Photosynthesis is crucial for phytoplankton and other primary producers, which 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 cannot 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 representing the depth where net primary production ends.

Nutrients are required by all marine primary producers, with nitrogen and phosphorus being the major nutrients required by phytoplankton. These nutrients occur in very small amounts in seawater, making them often the limiting factors for phytoplankton growth.

Why do tropical forests have high primary productivity?

Tropical rainforests have high net primary productivity due to their rapid plant growth and high rainfall. However, these forests quickly leach nutrients from their soils, which are typically low in nutrients. These nutrients are used by plants as raw material, making them always above ground. Tropical rainforests are characterized by vertical layering of vegetation and distinct habitats for animals within each layer. The forest floor consists of a sparse layer of plants and decaying plant matter, followed by an understory of shrubby foliage, a layer of trees, and a closed upper canopy.

These layers provide diverse and complex habitats for various plants, animals, and other organisms within the tropical wet forests. Many species of animals use the variety of plants and the complex structure of tropical wet forests for food and shelter. Tropical dry forests, which have varying lengths of dry seasons, often experience leaf loss during the dry season, allowing sunlight to reach the forest floor and the growth of thick ground-level brush. These forests are found in Africa, India, southern Mexico, and South America.

Why is the Pacific higher than the Atlantic?

Seawater’s density and volume can vary due to factors such as temperature and salinity. For example, sea levels are generally higher in the Pacific than in the Atlantic due to warmer, fresher, and less dense waters. To measure these changes, scientists have used radar altimeters, satellite-based instruments, to monitor ocean surface topography. These instruments send out radio waves that bounce off the ocean’s surface and reflect back to the satellite, calculating the time it takes for the signal to return and tracking the satellite’s precise location in space.

This allows scientists to derive the height of the sea surface directly underneath the satellite. Long-term records of tide gauges, collected since the early 19th century, have also been used to detect changes in the coastal ocean. However, due to uneven distribution of landmasses and islands and the clustering of tide gauges on wealthier countries’ shores, the view has been limited. Long-term records from over 1500 tide gauges help corroborate satellite observations.

Why is primary productivity typically higher in ocean upwelling zones?

Upwelling zones along the west coasts of continents, such as those found in California and Chile, are characterised by high productivity due to the presence of nutrient-rich waters and seasonal temperature variability, which can support significant primary production.