In ecology, the term productivity refers to the rate at which biomass is produced in an ecosystem. It is typically expressed in units of mass per unit volume (unit surface) per unit of time, such as grammes per square metre per day (g m-2 d-1), but it can also be expressed in units of mass per unit surface per unit of time. The unit of mass can refer to either dry matter or the mass of carbon that has been generated. Primary productivity refers to the productivity of autotrophs, such as plants, whereas secondary productivity refers to the productivity of heterotrophs, such as animals, and is the product of both primary and secondary productivity.
Secondary production is defined as the generation of biomass by heterotrophic (consumer) organisms in a system of interconnected systems. Because of the transfer of organic material between trophic levels, this represents the amount of new tissue that is produced as a result of the digestion and utilisation of assimilated food. In some cases, secondary production is defined as only the consumption of primary producers by herbivorous consumers (with tertiary production referring to carnivorous consumers), but it is more commonly defined as all biomass generation by heterotrophs.
Animals, protists, fungi, and a wide variety of bacteria are among the organisms responsible for secondary production.
Estimating secondary production can be accomplished using a variety of methods, including increment summation, removal summation, the instantaneous growth method, and the Allen curve method. The choice between these methods will be determined by the assumptions made by each method as well as the ecosystem under investigation. For example, whether or not to distinguish between cohorts, whether linear mortality can be assumed, and whether or not population growth is exponential are all questions.
The rate at which these consumers convert the chemical energy of the food they eat into their biomass for energy production. When energy is transferred from one trophic level to another, the efficiency with which this occurs is referred to as ecological efficiency. On average, it is estimated that only 10% of the energy transferred is transferred.
Methods for measuring secondary productivity
It is, in fact, quite straightforward. When it comes to field sampling, the most straightforward production methods to understand are those that follow a single age group (or cohort) from birth/hatching to harvest (Waters 1977, Benke 1984). Following the hatching of this hypothetical population, only mortality (a decrease in numbers) and individual growth (an increase in mass) occur throughout the remainder of the generation’s life cycle. Production between each interval can be calculated from population density and individual mass if the population is quantitatively sampled at regular intervals. Individual mass (∆W) increases, while density (∆N) decreases as a result of the increase in individual mass. The amount of products produced during the interval is calculated as ∆W times the mean density (Ñ) between the dates in the interval. P stands for total cohort production, and it represents the total amount of work done in overall time intervals.
P= ΣÑΔW
This straightforward approach takes into account both biomass losses due to mortality and the accumulation of biomass as a result of individual growth.
Net secondary productivity
NSP is calculated as follows: energy assimilated from food eaten – faeces + energy consumed for respiration = Net Secondary Production (NSP). Secondary productivity provides information about the food resources available to heterotrophic populations, such as humans, at various points in the food chain.
Absorption in consumers results in the accumulation of gross secondary productivity (GSP).
After accounting for respiratory losses, net secondary productivity (NSP) is defined as the increase in energy or biomass produced by consumers per unit area per unit time remaining.
Conclusion
Secondary productivity is defined as the rate at which consumers convert the chemical energy in their food into their biomass. In ecology, the term productivity refers to the rate at which biomass is produced in an ecosystem. Primary productivity refers to the productivity of autotrophs, such as plants, whereas secondary productivity refers to the productivity of heterotrophs, such as animals, and is the product of both primary and secondary productivity.
Secondary production is defined as the generation of biomass by heterotrophic (consumer) organisms in a system of interconnected systems. Estimating secondary production can be accomplished using a variety of methods, including increment summation, removal summation, the instantaneous growth method, and the Allen curve method.
NSP is calculated as follows: energy assimilated from food eaten – faeces + energy consumed for respiration = Net Secondary Production (NSP).