Microbial Diversity: Its Exploration and Need of Conservation - Applied Environmental Biotechnology: Present Scenario and Future Trends - page 45

Fig. 4.1 Microbial loop and aquatic food web. (Nardini et al. 2010 )

and their varieties, abilities, distributions, eco-
system functions, and conservation status need
to be further investigated. The primary cause is
habitat fragmentation, degradation, and destruc-
tion due to land use, change arising from con-
version, strengthening of production systems,
abandonment of traditional (which were often
biodiversity friendly) practices, construction,
and catastrophic events including fires. There
are some other key causes which include exces-
sive exploitation of the environment, pollution,
and the spread of invasive alien species (Nardini
et al. 2010 ).
Commonly used measures of biodiversity,
such as the number of species present, are strong-
ly scale dependent and only report a change after
a species is lost. There is no worldwide accepted
set of methods to assess biodiversity. The main
problem is that the data is much diverse and it
is physically discrete and disorganized. The so-
lution is to organize the information, and create
systems whereby data of different kinds, from
many sources, can be pooled. This will improve
our understanding of biodiversity and will allow
the development of measures of its condition
over time.

4.3.1 Impact of Anthropogenic

Activities

There are many reports depicting effect of
chemical pollutants such as polycyclic aromatic
hydrocarbons (PAHs) on microbial community
structure. PAHs are present in oil and coal and
produced by incomplete combustion of wood and
coal. They are widespread over the world and
are considered as heavy pollutants due to their
toxic, carcinogenic, and mutagenic effects on or-
ganisms. The study of bacterial communities in
PAH contaminated soils at an electronic waste
processing center in China shows that different
levels of PAHs might affect the bacterial com-
munity by suppressing or favoring certain groups
of bacteria, for instance, uncultured Clostridium
sp. and Massilia sp. , respectively (Zhang et al.
2010 ).

4.3.2 Reef Ecosystem

Most coral reefs are moderately to severely de-
graded by local human activities such as fishing
and pollution as well as global change; hence, it
is difficult to separate local from global effects.