To what extent does climate influence ecosystem productivity. June 2015
Ecosystem productivity is the rate of energy production or rate of creation of organic matter per unit area and time. It is measure in grams or kilocalories per year. It should be noted that productivity is a reflection of Biomass. That is, the higher the Biomass, the higher the productivity and vice versa. It should be noted that production measures rate while Biomass measures the total weight or mass of living organisms.
Basically there are two types of productivity namely, Primary productivity and secondary productivity.
Primary productivity is the rate at which green plants or primary producers create organic matter per unit area and time. This is usually achieved during photosynthesis, were green plants fix and convert energy. There exist two types of primary productivity; Gross primary productivity and Net primary productivity.Gross primary productivity is the total amount f energy created by green plants during photosysnthensis.
Net primary productivity is the amount of energy that is left oer, after losses through the respiration of plants.
GPP - RESPIRATION= NPP
Secondary productivity is the amount of energy converted into living matter by animals, (consumers or heterotrophic organisms).
The variations in the rate of ecosystems productivities are due to a number of factors which work in combination, rather that isolation. Such factors include climatic elements (sunlight, precipitation, temperature), Variations in nutrients supply and size of photosynthetic surface.
Climate is a dominat factor in the production of ecosystems due to its provisions of sunlight, precipitation, temperature as can be examined below.
The amount of intensity and duration of sunlight provided to the area influences productivity either high or low. This because sunlight is necessary during photosysnthesis, and it is during this process that ecosystem are most productive.
Equatorial areas have greater and higher intensity of solar radiations ans these significantly declines towards the poles. sun's rays fall vertically on a smaller area and less reflected, and absorbed by atmospheric impurities in equatorial areas, and days are longer than night during summers.
Conversly with increasing latitudes towards the poles sunlight intensities and durations varies greatly The rays of sun fall horizontally on a longer surface after travelling for a longer distance. Light durations are shorter espcially during winters with shorter days and longer nights.
How ever it should be noted that, though sunlight leads to higher productivity; it is not the case in all ecosystems reason being that, solar radiation works in combination with other factors like water and vegetation which are ideal conditions for photosynthesis.
This is another factor of ecosystem productivity as it is a condition for primary productivity because it stimulates photosynthesis.
Precipitation as a climatic element determines moisture availability and also a medium of nutrients movement in plants necessary for production of organic matter. The Selva or tropical rain forest ecosystem with high rain fall of 2500mm, increases soil moisture content and soil moisture budget surplus.
Deserts with low precipitation of 250mm/ year have low productivity irrespective of high sunshin intensity. The polar and Tundra regions have low rainfall and is even in the form of snow or frozen soil retards bacteria action and photosynthesis.
It should be noted that moisture works in combination with other factors. This is because aquatic ecosystem have the greates moisture of all but low NPP because of low nutrients content and inadequate surfaces for photosynthesis.
The size of the photosynthesis surface also influences productivity of ecosystems. Grasslands hve low productivities than forest with high rates of productivities. This is a reflection on the size and amount of photosynthetic surface exposed to sunlight for photosynthesis
The rate of cycling and the amount of nutrient supply. This is a major factor that affects the productivities of ecosystems. The supply of nutrients varies from place to place as a result of variations in climatic conditions. The rainforest with humid equatorial climate characterized by high rainfall of 2500mm, high temperature of 28° C, favor deep chemical weathering which releases enough nutrients to the soil.