The Thin Layer of the Atmosphere – Biosphere
Before the evolution of life, Earth was a blurred place, a rocky globe with seas and a thin band of gases—mainly carbon dioxide, carbon monoxide, hydrogen sulfide, molecular nitrogen, and water vapour. Earth was a hostile and barren planet.
The biosphere is one of those thin layers of gas that supports life, by shielding the stratum of the Earth’s surface. The biosphere extends from a few kilometers into the atmosphere to the deeper in the sea vents of the ocean. This layer is a global ecosystem that is composed of living organisms like biota and the abiotic which are the nonliving factors that derive energy and nutrients.
The Efficiency of Solar Energy Utilization
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Majorly the solar energy occurs at wavelengths that are unsuitable for the process of photosynthesis. The 98 and 99 percent of solar energy which reaches the Earth is reflected from the leaves and other surfaces and it gets absorbed by other molecules, which thereby gets converted to heat. So, we can estimate that only 1 to 2 percent is available for the plants which they capture eventually. The plant processing the photosynthesis process depends on the amount of light that reaches the leaves, it also depends on the temperature of the environment, and on the availability of water and other nutrients like phosphorus and nitrogen. The measurement is also included which indicates the rate at which the organisms convert the light energy (or the inorganic chemical energy) to the chemical energy of organic compounds, this is called the primary productivity.
Thus, the total amount of energy that is being assimilated by the plants in an ecosystem during the process of photosynthesis varies in different environments.
A major part of the energy that is assimilated by the plants through the process of photosynthesis is not stored as organic material, rather they are used in cellular respiration. This is the process where the organic compounds like carbohydrates, fats, and proteins are broken down, they get oxidized, in order to provide energy (in the form of ATP. The energy which is not being used in this process is stored in the tissue structure of the plant for further use and this is called net primary productivity.
Approximately about 40 - 85 percent of the gross primary productivity is not used during the process of respiration and thus, becomes net primary productivity. The highest net primary productivity in the terrestrial environments occurs in marshy lands, swamps, tropical rainforests. While the lowest occurs in the desert regions. In the aquatic environments, the highest net productivity happens in estuaries, reefs, and algal beds. These types of environments are critical for the maintenance of the world’s biological productivity.
Biosphere Efficiency of Solar Energy Utilization
Viv Forbes – “Green energy is not so green after all. It reduces the supply of food, water, and energy available to all life on earth, and it often consumes large amounts of hydrocarbon energy for its manufacture, construction, maintenance, and backup.”
Our planet earth has three significant sources of energy, they are – Geothermal energy, combustible hydrocarbon minerals energy, and radiation or gravitational pull from the sun and moon energy.
The functioning of the biosphere is solely not dependent on the maintenance of the intimate interactions which are among the myriad species that are within the local communities but this is also on the loser yet the crucial interactions of all these species and communities living around the globe.
Our earth is covered with so many species and so many different kinds of communities, hence the populations have been able to adapt to any kind of environment on Earth through natural selection. Life-forms evolved who are able to survive in the ocean depths and even in the frigid conditions of Antarctica. Life forms are also existing in the near-boiling temperatures of geysers. The greatest richness of adaptations that are being found among the different populations and species of living organisms is the Earth’s greatest resource. This is a richness that has evolved over millions of years and this is quite irreplaceable.
In the process of photosynthesis, light energy gets absorbed by the chlorophyll molecules of the plants and this gets converted into carbon dioxide and water into carbohydrates and oxygen gas. The proteins, fats, nucleic acids, and other compounds also get synthesized during the process, this happens as long as the elements such as nitrogen, sulfur, and phosphorus are available here.
Worldwide Biological Productivity
Productivity is generally measured by an increase in biomass. World Biological Productivity is a term used to refer to the weight of all the living organisms living in an area. The Biomass is reported in grams or metric tons.
The effects of species richness on biological productivity are at an ecosystem level (which means inter-populational) or in the level of landscape-level (that is inter-ecosystemic) processes. This goes beyond the simple sorting of the species into their suitable portions with their own habitat. The contextual effects boost or reduce the productivity of the species that are occupying a given amount of habitat.
Loreau and Hector in the year 2001, called the positive interspecific contextual effects “facilitation”.
“Allelopathy” means the poisoning of one plant species by another, this is an example of a negative contextual effect. With this addition the processes occurring within ecosystems, and the interactions developing between the ecosystems (that is the landscape-level processes) it is conceivably and also affects the individual species’ productivity. For example, even more, diverse ecosystems resisted the invasion by the non-native species which is better than less diverse ecosystems. This depends on the way the invaders affect the productivity of the species which is already there.
FAQs on Efficiency of Solar Energy Utilization
1. What is the biosphere and its role in solar energy utilization?
The biosphere is the thin layer on the Earth's surface that contains all life. It extends from a few kilometres into the atmosphere to the deep-sea vents. Its primary role in energy utilization is to support photosynthesis, the process by which living organisms, mainly plants, capture solar energy and convert it into chemical energy, forming the foundation of nearly all ecosystems.
2. How efficient is the process of photosynthesis in capturing solar energy?
The process of photosynthesis is relatively inefficient in terms of total energy capture. Only about 1 to 2 percent of the solar energy that reaches the Earth's surface is captured by plants. A significant portion of solar energy is either reflected or occurs at wavelengths unsuitable for photosynthesis.
3. What is the difference between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP)?
Gross Primary Productivity (GPP) is the total rate at which solar energy is converted into organic compounds by plants during photosynthesis. However, plants use a portion of this energy for their own metabolic activities through cellular respiration. Net Primary Productivity (NPP) is the remaining energy that is stored as biomass after subtracting the energy lost to respiration. NPP represents the energy available to the next trophic level (herbivores).
4. What are the main factors that limit the primary productivity in terrestrial and aquatic ecosystems?
The primary productivity of an ecosystem is limited by several key factors. In terrestrial environments, these include:
- The amount of sunlight reaching the leaves.
- The ambient temperature.
- The availability of water.
- The presence of essential nutrients like nitrogen and phosphorus.
5. What is biomass and how is it used to measure biological productivity?
Biomass refers to the total weight of all living organisms in a specific area at a given time. It is a key indicator used to measure the biological productivity of an ecosystem. An increase in biomass over a period indicates positive net primary productivity, showing how much new organic matter has been created and stored. It is typically reported in units of mass per unit area, such as grams or metric tons.
6. Why is most of the solar energy reaching Earth not used for photosynthesis?
The vast majority (about 98-99%) of solar energy is not used for photosynthesis for two main reasons. Firstly, much of the sunlight is at wavelengths that chlorophyll cannot absorb. Secondly, a large amount of the suitable light is reflected off surfaces like leaves or absorbed by other molecules and converted directly into heat. Therefore, only a very small sliver of the total available solar radiation can be captured and converted into chemical energy by plants.
7. How does cellular respiration impact the total energy available to other organisms in a food chain?
Cellular respiration significantly reduces the total energy passed up the food chain. Plants use a substantial amount of the energy they produce (GPP) for their own life processes like growth and repair. This energy, lost as heat during respiration, is no longer available to herbivores that eat the plants. The energy that remains, known as Net Primary Productivity (NPP), is what constitutes the base of the food web and supports all other life forms in the ecosystem.
8. Compare the environments with the highest and lowest net primary productivity. What explains this vast difference?
Environments with the highest NPP include tropical rainforests, marshes, and estuaries. Those with the lowest NPP are typically deserts and open oceans. The vast difference is explained by the availability of limiting factors. High-NPP environments have abundant sunlight, water, warm temperatures, and nutrient-rich conditions, which are ideal for plant growth. Conversely, low-NPP environments like deserts lack water, while open oceans are often nutrient-poor, severely restricting the rate of photosynthesis.
