ECOSYSTEM CHANGE AND ENVIRONMENTAL IMPACTS
Human activities and natural disasters can cause changes in an ecosystem.
Natural disasters, such as volcanic eruptions and earthquakes are something that is
beyond human control. However, human activities, such as pollution and excessive
exploitation of natural resources, will directly or indirectly result in ecosystem changes.
Destruction of the habitat of a community will directly change the ecosystem in that
habitat. For example, the exploitation of fish in lakes or rivers using explosives, electric
currents or toxic substances results in the destruction of community habitats in
lakes/rivers and subsequently causes ecosystem changes and biodiversity decline.
In freshwater ecosystems, there are limiting factors that allow the mechanisms
that take place in the ecosystem to run steadily. These limiting factors are related to the
habitat conditions of freshwater ait (aquatic environment), namely:
1. Temperature
2. Transpiration
3. Turbidity/turbidity
4. Current
5. Gases are dissolved in water
6. Dissolved Oxygen (DO)
7. Dissolved carbon dioxide
8. Biogenic salts in water
9. Na and K
10. Calcium and Magnesium
11. Phosphorus
12. Water convection
With the disruption of the above limiting factors, for example an increase or
decrease in the concentration and magnitude of these factors, it will undoubtedly affect
the community and the abiotic environment of the lake/river ecosystem. Examples of
cases due to water pollution from the waste of a paper mill that have a negative impact
on the environment and damage to the ecosystem, are as follows:
1. Disturbance of vegetation
Rice plants in rice fields in polluted areas are often attacked by wilt disease with
symptoms of dried and rotting leaf shoots and ending in the death of the plant.
2. Disturbances to fauna
Animals and poultry that drink the polluted river water die or produce defective
offspring.
3. Interference with humans
In cultivating rice fields, farmers must change the way they plant rice, especially
in the dry season, because throughout the planting season there are a lot of layers
of paper that settle and cover the soil surface; Farmers have to provide extra labor
to pick up the layer of paper that settles covering the soil surface, which means
increasing production costs. From an example above, it is clear that disturbances
or pollution to the environment will result in the occurrence of
A. BIOLOGICAL CONTROL OF THE CHEMICAL ENVIRONMENT
Organisms adapt to the physical environment (xerophytes, halophytes, and
hydrophytes), but organisms can also make the geochemical environment adapt to their
biological needs. In other words, organisms can affect their environment. For example,
plants can affect the soil where they grow, Coelenterata can form rocks that affect the
environment, and humans can change the boundaries for their own benefit
B. PRODUCTION AND DECOMPOSITION IN NATURE
In nature, there is always a production process as a result of photocytosis from
producer organisms. As an illustration, it can be mentioned that the result of
photosynthesis per year can reach 1017 grams. Besides the production process in nature,
there is also always a decomposition process. There are three stages of the
decomposition process, namely:
1. The formation of small granules of remains by biological action.
2. Production of humus and release of soluble organic substances by saprotroph
3. Mineralization of humus.
In this process, bacteria are important in the destruction of meat, while fungi are
important in the wood process if large organisms die (including plants) will become a
special habitat for microorganisms and are broken down by detrivores e.g. insects) into
detritus. Although insects do not eat cellulose, it does help break it down because:
1. Breaking wood into small pieces so that it is easy to eat
2. Produce growth factors.
3. By eating, bacteria maintain natural bacterial populations in a log-phase state,
where bacteria develop very quickly.
Some detrivores are Coprophagus, which is a pellet eater after the pellets are
enriched by microbes, for example popilus (a type of beetle) that lives on decaying
wood uses the duct of its house as an outside house where the dung pellets and wood
chews enriched by fungi are eaten again so as to accelerate the decay of wood.
Coprophagus in this case involves the cooperation of insects and fungi and allows
beetles to harness wood energy and accelerate wood decay
Organic substances resulting from decay have a specific influence on the growth of
other organisms in the ecosystem. This substance by Julian Huxley (1935) was called
external diffusion hormone, while Lucas mentioned ectorine or environmetal hormone
or exocrine. These substances can inhibit the growth of other organises such as
antibiotics or stimulate growth such as vitamins (thiamin, biotin, B12), uracil, and
histidine
Saprotroph holds a role in the production of exocrine. An important phenomenon is
the production of volatile secretions called pheromones, which can inhibit the behavior
of insects and other organisms. According to Winogradsky, organisms that decompose
humus are called zymogenius, while those that decompose humus are called
autochathonous. Detritus, humus, and other compounds that cause decay play an
important role in soil fertilization. Complex organic compounds along with minerals
can be absorbed by plants and the formation of complex organic substances along with
minerals is called chalation.
Organic degradation controls a number of functions in an ecosystem such as:
1. Recirculation of nutrients through mineralization.
2. Food formation in the detritus food chain.
3. The formation of extorin is regulating.
4. Modifying virgin materials from the ground.
Humans can accelerate decomposition by:
1. Changes in organic matter (fossil fuels) that add CO2 to the air. CO2 can be
penetrated by sunlight causing a greenhouse effect, and causing temperatures to
rise and if this happens, it will melt polar ice so that it can raise sea levels.
2. Agricultural efforts will accelerate the decomposition of humus.
C. HOMEOSTATIC ECOSYSTEM
Ecosystems are able to maintain and govern themselves just as much as the
components that make them up are organisms and populations. Therefore, cybernetics
(control science) has an important role in ecology because humans tend to mess up the
natural control system.
Homoestatic is a term for the tendency of biological systems to resist change and always
be in balance.
• That ecosystems are able to maintain and regulate themselves like the
components that make them up (organisms and populations).
• Therefore, cybernetics (control science) has an important role in ecology because
humans tend to mess with natural control systems.
• Homeostatic: the tendency of biological systems to resist change and always be
in balance. Homeostatic ecosystems
