dioxide, water, and mineral nutrients. Lack of any one of these may limit photosynthesis or primary production. Which factors limit primary production in the Arctic Ocean?

Light and nutrients are important in limiting primary productivity, and are contributing factors to the great variability which one may encounter within a given lake.

Net primary productivity varies among ecosystems and depends on many factors. These include solar energy input, temperature and moisture levels, carbon dioxide levels, nutrient availability, and community interactions (e.g., grazing by herbivores) 2.

In terrestrial ecosystems, temperature and moisture are the key factors limiting primary production.

• Tropical rain forests, with their warm, wet conditions, are the most productive of all terrestrial ecosystems.
• By contrast, low-productivity ecosystems are generally dry (deserts) or dry and cold (arctic tundra).

We focus on two major variables—light and nutrients—and their role in determining primary production. Grazing and sinking, the other major factors affecting producers, are discussed in Chapters 5 and 13.

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, as illustrated in the following figures. In terms of NPP per unit area, the most productive systems are estuaries, swamps and marshes, tropical rain forests, and temperate rain forests (see Figure 4).

Net Primary Productivity (NPP), or the production of plant biomass, is equal to all of the carbon taken up by the vegetation through photosynthesis (called Gross Primary Production or GPP) minus the carbon that is lost to respiration.

Gross primary productivity is the amount of carbon fixed during photosynthesis by all producers in the ecosystem. However, a large part of the harnessed energy is used up by the metabolic processes of the producers (respiration).

Solar energy

Primary production is when plants make their own food and use that food to live and grow. These plants do not depend on other plants, animals, or insects for their food. They can make their own with help from the sun, water, and air. Common primary producers in a schoolyard ecosystem are: grass.

Primary production: this involves acquiring raw materials. For example, metals and coal have to be mined, oil drilled from the ground, rubber tapped from trees, foodstuffs farmed and fish trawled. This is sometimes known as extractive production.

Diatom

Primary productivity is the conversion of the sun’s energy into organic material through photosynthesis. Primary productivity is important because it is the process that forms the foundation of food webs in most ecosystems.

Humans appropriate NPP in a variety of ways, for example, land conversion into: urban or built-up land, agricultural land, and managed forests. Other effects include human-induced fires, desertification, and large scale ecosystem degradation.

The effect of temperature change is generally positive to increase the productivity by enhancing the photosynthesis as long as the temperature is in a range of optimum level. When temperature exceeds the optimum level, it will increase the rate of respiration causing the NPP continuously declined.

A high primary productivity rate in the ecosystems is obtained when the physical factors (for instance: water, nutrients and climate) are favourable. The presence of some forms of secondary energy can also help to increase the primary productivity rate.

The productivity of autotrophs, such as plants, is called primary productivity, while the productivity of heterotrophs, such as animals, is called secondary productivity.

about 70 per cent

central Arctic Ocean

Higher chlorophyll concentrations and in general higher productivity are observed on the equator, along the coasts (especially eastern margins), and in the high latitude ocean (Figure 4a and b).

Primary productivity can be measured from the amount of oxygen consumed by a volume of water in a fixed period of time; water for which productivity is to be determined is enclosed in sealed white and dark bottles (bottle painted dark so light would not enter).

ocean pt 2

Estuaries are one of the most productive ecosystems on earth. They maintain water quality through natural filtration as microbes break down organic matter and sediments bind pollutants. Much of the sediments and pollutants are filtered out as the water flows through these fringing marshes.

Ocean Productivity. Abiotic factors like solar radiation and nutrients, and biotic factors like zooplankton predation may affect ocean primary productivity. Productivity varies with the season, and also locally and globally.

why is there no primary productivity in most of the deep oceans? the sunlight and warmth, never reach the bottom. Without sunlight there is no photosynthesis, there’s insufficient energy accumulated to support a great abundance of multicellular organism.

Factors that limit the productivity of estuary ecosystems include: The need to survive osmotic stress; The depletion of the oxygen in the sediments.