Biomass Definition Ecology

Introduction

Biomass refers to any and all organic material that can be derived from plants including trees, crops, and algae. It has been an important source of energy from time immemorial and offers various benefits over its nonrenewable counterparts. In India, about 32% of the total energy needs are met by one or the other form of biomass.

Define biomass

Biomass is the short-term given to biological mass. It refers to the amount (SI unit kg/m²) of living and non-living organisms residing in a specific environment or ecosystem. It includes both terrestrial and aquatic organisms. It includes microorganisms, animals, and plants. The study of biomass is significant for commercial use leading to national development (Fiber, fuel, etc.). It also helps in scientific studies involving ecosystem productivity, nutrient and energy balances, and the effect of each component on the global carbon cycle.

Various parts of a biome

The 6 major parts of our biome are −

• Desert Biome − They are hot and dry areas and constitute about 20% of the earth’s total land. They are further divided into Semi-arid, Hot and dry, Cold, and Coastal deserts.

• Forest Biome − Mainly composed of trees and vegetation plantations capable of storing carbon, they constitute about 30% of the earth’s total land. They are further sub-divided into Temperate, Tropical, and Boreal forests.

• Aquatic Biome − They are the water bodies present on the earth's surface and constitute about 75% of the total earth. They are subdivided into Freshwater and Marine Biomes.

• Tundra Biome − They are the coldest land biome and constitute very less biodiversity. They are subdivided into Alpine Tundra and Arctic Tundra Biome.

• Grassland Biome − They refer to the areas of extensive grass species, with or without a small number of scattered trees. They are sub-divided into Temperate and Savanna Grasslands.

• Shrubland or Chaparral Biome − They mainly refer to the shrubs which are dry and hot in summers while moist and cool during the winters. They are found only in a few regions of the world.

Pyramid of biomass

The pyramid of biomass refers to the graphical representation of different kinds of biomass present in a unit area at multiple trophic levels. The two major kinds of biomass pyramids are the inverted pyramid and the upright pyramid. The biomass pyramids are significant in carrying out available biomass quantification at every trophic level.

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Examples of biomass (terrestrial and ocean)

Terrestrial biomass refers to the ecosystem that resides on the land. Plants and vegetation are the predominant species of terrestrial biomass and act as the producers. Herbivores like buffaloes, cows, giraffes, zebras, deer, small insects, etc. are the primary consumers feeding on the producers. The secondary consumers, for. e.g, lions, tigers, snakes, bears, etc. feed mainly on the primary consumers. The amount of biomass follows the following pattern − plants > primary consumers > secondary consumers.

The ocean (or aquatic) biomass refers to the flora and fauna occurring in the water bodies. Here, the phytoplanktons are the primary producers. The zooplanktons (e.g., mites, rotifers, etc.) are the primary consumers while piranhas, sharks, etc. are the secondary consumers in the aquatic biome.

Availability of biomass

According to a recent study conducted by the Ministry of New and Renewable Energy (MNRE), Government of India, the present availability of total biomass in India is estimated to be about 750 million metric tonnes per annum which is a surplus of approximately 230 million metric tonnes per annum.

Obtaining energy from biomass

Plants convert solar energy into chemical energy for their later use. This chemical energy (carbon compounds) could be used to convert it into heat or electrical energy or could be converted to biofuels as energy sources. Various forms of energy that could be obtained from biomass are −

• Wood − All or any part of the wood (sawdust, logs, wood pellets and chips, and tree bark) could be used to obtain energy through combustion, cogeneration, or gasification.

• Agricultural products − Plant-based materials, both energy crops, and their residues could be heated to produce energy to run boilers. Most of the time this energy is reused in the same agricultural processes, thereby decreasing the overall cost of the process. They could also be used to produce bio manure or compost.

• Biogas − Biogas or methane could be generated by microbial action of dead biomass to produce energy for cooking and heating.

• Landfills − Waste is generally dumped at designated sites where it forms large heaps over a long period of time. They release various gases which could be collected and used for heating purposes.

• Biofuels − Bioethanol and biodiesel could be produced from waste biomass through biochemical routes. These fuels are less polluting than their fossil counterparts.

Benefits and limitations of biomass

Biomass offers various advantages such as −

• Biomass provides a renewable source of energy that is comparatively clean, free, reliable, and continuous.
• It helps in waste reduction.
• It does not contribute any extra carbon to the environment hence mitigating pollution.

The limitations associated with biomass are −

• It requires a high cost of initial setup.
• It requires large operational spaces.
• It offers low efficiencies as compared to fossil fuels.

Effect on environment

Biomass energy helps in protecting our environment as the amount of carbon dioxide released by burning biomass-derived fuels is similar to the amount captured by plants during photosynthesis. Therefore, it could be considered a carbon neutral process. However, some amounts of pollutants are released during the conversion process of biomass to bioenergy.

The process used for biomass conversion to energy

Various methods used to convert biomass to energy are −

• Direct combustion − It is the most widely used method of obtaining energy from biomass. Biomass could be directly burned to produce heat that could be used for heating water, buildings, industrial processes, and generating electricity through steam turbines.

• Thermochemical process − It includes either pyrolysis or gasification of the biomass. While pyrolysis is the thermal decomposition of biomass in the absence of air taking place at lower temperatures (400-500 ℃), gasification takes place at much higher temperatures (800-900 ℃).

• Biochemical process − It refers to the use of microbial enzymes to decompose the carbohydrate portion of biomass through various processes like fermentation, anaerobic digestion, or composting enabling the availability of sugars. These can be further processed either microbially or chemically to produce liquid or gaseous fuels.

Conclusion

Biomass is a renewable energy resource that involves the burning of plant and animal waste. Almost all industrial waste contains components that could be transformed into useful energy. Considering the disadvantages associated with the use of nonrenewable energy, thrust is being given to the development of efficient technologies for biomass conversion to bioenergy.

FAQs

Q1. How is biomass measured?

Ans. Biomass is calculated by measuring the dry weight of an organism and dividing it by the area from which it has been harvested.

Q2. What do you understand by the term biome?

Ans. Biome refers to a similar group of ecosystems that share the same characteristics and have adapted themselves to the surrounding abiotic factors.