What is an ecosystem?

We explain what ecosystems are and what types of ecosystems exist. In addition, how they are composed and some examples.

1. What is an ecosystem?

An ecosystem , in biology , is called the complex gear of relationships between the different communities of living organisms (referred to as biocenosis ) and the physical environment in which they live (called habitat or biotope ). In this concept the relations of mutual dependence between the species of living beings , as well as the flow of energy and matter that occurs in the environment; processes that for their study are understood as a structured and organized whole.

However, the concept of ecosystem should not be confused with that of biome . The latter refers to the different geographical areas or regions of the planet Earth , classified according to their climate , topography and also their presence of life , unlike ecosystems, biomes are considered homogeneous geographical units. Thus, the same biome can contain several different ecosystems .

Trophic or food chains take place within each ecosystem , also understood as cycles of matter transmission, as they consist of a food circuit that includes producers (vegetables, plants, phytoplankton, etc.) that feed on the physical environment , consumers who feed on them or other consumers (both herbivores, as primary and secondary predators) and finally decomposers (fungi, bacteria, etc.) that recycle residual organic matter .

Many ecosystems are currently in a state of check due to human industrial activity . The pollution , overfishing , deforestation and the effects of the climate change often involve extinctions, overpopulations, mutations and displacements of life of all kinds, preying on the biodiversity  and against the natural balance.

2. Ecosystem types

There are several types of ecosystem, classified according to the habitat in which they are located:

• Aquatic ecosystems . The most abundant, almost 75% of all known ecosystems take place underwater . That is to say: in seas, oceans , rivers, lakes and deep underwater niches.
• Terrestrial ecosystems . They take place on the earth’s crust and out of the water, in its possible relief variations: mountains , plains, valleys, deserts , etc. This implies important differences in temperature, oxygen concentration and climate , so the diversity of life in these ecosystems is huge, mostly of insects and birds.
• Mixed ecosystems . Those in which the aquatic and terrestrial (amphibious) are combined, since the animal life of these ecosystems is mostly in one of the two, but they require the other to rest, feed or procreate.
• Microbial ecosystems . It is that of microscopic organisms that inhabit virtually all environments, both aquatic and terrestrial, and even within larger organisms, as is the case with intestinal microbial flora.

3. Components of an ecosystem

An ecosystem is composed of two types of elements, different in nature: biotics and abiotic:

• The biotic elements are those linked to life in its many forms and trends, such as trophic relationships, plant presence, population balances, etc.
• The abiotic elements , on the other hand, are those referring to climatic conditions, relief , or other chemical and / or physical variants that concern the environment, such as the variation of pH , the presence of sunlight , etc.

4. Ecosystem examples

• Coral reefs . Of the largest concentrations of life in the underwater world, it takes place in and around the coral structures that form a natural barrier. There are numerous small species (fish, crustaceans, mollusks) due to the abundance of organic matter, serving in turn as food for predators.
• Abyssal underwater areas . Extreme ecosystems, with little animal presence and no plant presence, since the absence of sunlight prevents photosynthesis . Life, however, adapts to the enormous water pressure and the low amount of nutrients. Much of it is sustained from a constant rain of organic matter coming from the surface, or through chemosynthesis.
• Polar ecosystems . It is characterized by very low temperatures and low atmospheric humidity. Despite this, it has a sea rich in plankton and animal life adapted to icy waters: hairy bodies, dense layers of fat, etc.
• Lotic Ecosystems They take place inside and on the banks of rivers, streams or springs that are on the earth’s surface. Life in them adapts to the flow of water, which carries with it nutrients, chemicals, living species or simply very oxygenated water in its movement.