Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

 
4.1.3.  Biosphere
1
The biosphere is the part of the Earth’s environ ment in which 
living organisms are found, and it comprises the upper part of the 
litho sphere, the lower part of the atmo sphere (tropo sphere) and the 
entire hydrosphere. The biosphere is simultaneously the entirety of all 
living beings (biomass) and their habitat environ ment. The bio sphere 
is the space inhabited by living organisms in different con centrations. 
Whereas there are only a few bacteria per cubic meter in the upper 
layers of the atmo sphere, there is not only high biological diversity 
but also a huge number of individuals within a specific unit area in 
the tropical rain forests of the equatorial zone. The biosphere is an 
extremely  complicated  and  dynamic  system  which  is  affected  by  a 
multitude of different external factors, including contingent ones, such 
as the tectonic processes in the Earth’s crust, ice covers and natural 
disasters.
The total estimated global mass of living biological orga nisms is 
the biomass, and it ranges from 2.4 × 10
12 
tons to 1 × 10
13 
tons of dry 
matter, the largest part of which is phytomass (phyto plank ton, trees, 
grasses), whereas the amount of zoomass is estimated from 2 to 10 per 
cent of the total biomass. The total of approxi ma tely 2.3 × 10
11 
tons of 
biomass is produced annually. Biomass con sti tutes 0.01% of the mass 
of the Earth’s crust, and it would make a 2 cm layer if it were evenly 
dispersed over the Earth’s surface. The largest amounts of biomass are 
concentrated  in  tropical  rain forests  –  65  kg/m
3 
on average, whereas 
in  boreal  forests  (taigas)  it  is  20-25  kg/m
3
,  in  fertile  zone  steppes  – 
1 kg/m
3
, in deserts – 0.25 kg/m
3
. The concentration of biomass in the 
World Ocean at large is close to that of deserts, while in some places it is 
comparable to steppes and savannas. However, marine organisms have 
higher rates of repro duction and decomposition because their biological 
cycling is more inten sive. Plankton is the largest and most significant 
community of living organisms on this planet. Although the mass of 
living matter is relatively small compared to the mass of the Earth’s 
crust, the cycling processes there are much more intense. It is estimated 
1 
This chapter has been prepared with contribution of prof. V. Melecis.
The total number of 
hitherto known species 
of animals and plants 
reaches almost 3 million; 
from these, almost 
300 000 are autotrophs, 
i.e. organisms producing 
the primary biomass. All 
other organisms are he‑
terotrophs – they are the 
consumers of the primary 
biomass. Angiosperms 
have the largest number 
of species among plants, 
whereas insects, molluscs 
and vertebrates cham‑
pion among animals. 
Fungi – being neither 
plants nor animals – have 
a special place among 
living organisms. They 
also are heterotrophs and 
have a vast number of 
species.

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50 
ENVIRONMENT, POLLUTION, DEVELOPMENT:  THE CASE OF UZBEKISTAN
that the biomass produced by plankton during the entire period of its 
existence on the Earth by far exceeds the mass of the Earth’s crust.
Living systems – unlike the non-living ones – actively inter change 
with the environ ment, constantly taking organic and inorganic sub-
stan ces and energy from it and excreting the waste products of life 
pro cesses back into the environ ment. The main categories of living 
systems are cell, organism, population and species community. Cells 
and organisms are excitable, i.e. they actively react on environ men tal 
changes, grow, develop and reproduce. The cell is the basic structu-
ral element of organisms, the organisms of one species make a popu-
lation, while the species that are interrelated or have similar demands 
from the environ ment con stitute commu nities of species. A species 
commu nity and its non-living environ ment inhabited, used and 
trans formed by the species together make a system of a yet higher 
category – an ecosystem, in which the components of both organic 
and inorganic nature are combined. Each species is unique, and it 
has specific and distinctive functions in the ecosystem. All species of 
organ isms living on the Earth can be classified into four kingdoms: 
bacteria, fungi, plants and animals (viruses are not included in this 
classi fication).  Even  if  the  number  of  already  classi fied  species  is 
over whelming, it is deemed that scientists have not yet dis co ve red the 
greatest part. It is estimated that the total number of species on the 
planet could be at least 13 million. 
The living components of an ecosystem are made up of the 
organisms of different species that populate the same habitat, usually 
interact and make a food chain. The whole of species within an 
ecosystem is called a species community. The whole of all components 
of non-living nature (rocks, water, air) that host a species community 
is called a biotope (Figure 4.5).
Ecosystems  can  be  of  different  sizes,  from  micro-ecosystems, 
such as a rotting stump or a puddle, to meso-ecosystems and macro-
ecosystems, such as a forest plot, a lake, the island of Madagascar 
or  the  Pacific  Ocean.  All  the  ecosystems  of  the  planet  constitute 
the mega-ecosystem – biosphere (Figure 4.6). Ecosystems are open 
systems, which means that they continuously receive and emit 
energy and different substances.
Biotope
Biotope + species community = ecosystem