We explain everything you need to know about ecosystems and their diversity.
An ecosystem can be defined as a system of living organisms that interact with each other and with the environment in which they are found . The classification of ecosystems is complex, since even in very similar regions we can find different ecosystems that function in radically different ways.
In this article we will talk about ecosystems and how we can broadly classify them. It is impossible to say that there is a specific number of ecosystems, as we will see below, but we can group them according to their characteristics to facilitate their study.
What is an ecosystem?
Ecosystems are basically networks of relationships between different living beings and the environment in which they coexist . The base of the ecosystem is usually vegetal, since the plants are capable of generating the biomass necessary for the maintenance of the system from the inorganic nutrients of the ecosystem.
Even so, there are ecosystems that do not depend on the presence of plant life to sustain themselves , as would be the case of the ecosystems that appear around hydrothermal vents (ecosystems supported by bacteria capable of generating energy from chemical reactions with components emitted by the vents). ). This testifies to the enormous diversity of ecosystems present on planet earth.
To broaden the definition of ecosystem, we can speak of them as organizations of living beings, through which mass and inorganic energy flow and are transformed, allowing the maintenance of life. We could consider planet earth in its entirety as a single ecosystem, just as microbiomes, which are organizations of different microorganisms, are also considered ecosystems.
In this article we will keep to the scale visible to the human eye of ecosystems and we will talk about the classic classification of these, but we must bear in mind that there are countless types of ecosystems supporting all forms of life on our planet .
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Types of ecosystems
When we talk about types of ecosystems we find ourselves with the problem of defining the scale of the ecosystems that we are going to study.
Even so, we can separate most ecosystems in which plants and animals coexist into 2 main types , which in turn are separated into the rest of different subtypes. These would be the terrestrial and aquatic ecosystems .
Below we discuss some of the subtypes into which these ecosystems are divided.
Terrestrial ecosystems
These are, as the name suggests, ecosystems in which organic activity takes place primarily on dry land .
Although a minimum amount of water is necessary for life, these ecological systems occur in areas with less water than aquatic ecosystems, where water is the protagonist in the development of the ecosystem.
1. Forest ecosystem
Forest ecosystems are characterized by their high concentration of plants, especially trees. These trees mark the characteristics of the environment, where wide expanses of uninterrupted land are rare. The greater the density and age of the forest, the greater the biodiversity expected in it .
Thanks to the trees of the forest ecosystem, the animal species that manage to adapt find food and shelter. This allows forest ecosystems to harbor a high biological diversity.
Some examples of forest ecosystems would be, for example, primary forests, such as the Amazon rainforest in South America or the old forests of northern Europe.
2. Tundra ecosystem
Tundra is an ecosystem whose name comes from the Lappish language, where it roughly means barren or treeless land . This type of ecosystem differs radically from the forest ecosystem, due to its marked absence of tree vegetation, with most of the vegetation being small herbs, moss and lichens.
It can be found at high latitudes in the northern hemisphere, throughout Europe, Russia, Greenland, and Canada . They are characterized by the intense cold that can occur in these areas, where the average temperatures never rise above 10ºC.
At the animal level, we will find herbivores such as the arctic hare and carnivores such as bears and some types of falcons . Salmon are an important part of the food chain in these areas, providing food for various species.
3. Desert ecosystem
Desert ecosystems are usually associated with heat, but cold deserts also exist . The main characteristic of deserts is their low availability of water. These low humidity levels normally occur due to the distance from the ocean and the presence of mountainous structures that block the passage of rain to the desert area.
Deserts occupy approximately 20% of the planet’s land masses and are usually located between 15º and 35º, in both hemispheres.
On an ecological level, desert life has become accustomed to low water availability and extreme temperatures, through evolutionary adaptations that help them better retain water and regulate its temperature effectively. Some classic examples of desert climates are camels or cacti.
4. Prairie ecosystem
Grasslands are ecological zones where the predominant vegetation is herbaceous plants . They usually need between 600 and 1500 mm of annual rainfall and their temperatures are usually in the range of -5ºC and 20ºC, although there are some that exceed these extremes.
A curious fact about grasslands is that the dominance of herbaceous plants and the scarcity of tree vegetation occurs because these ecosystems are subject to some type of stress that limits the growth of tree vegetation . This stress can be in the form of grazing animals or periodic fires (man-made or naturally occurring), for example.
Some grasslands are produced by human action , since we ourselves are the ones who deforest areas to feed our animals, among other activities. Several European prairies are believed to have their origin in the Neolithic, due to the appearance of livestock.
There are several different examples of grasslands, such as the African savannahs, the Llanos in South America, or the European steppes.
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aquatic ecosystems
Aquatic ecosystems tend to have less defined boundaries than terrestrial ones, because they exist in the aquatic environment.
Even so, we can find some general types of aquatic ecosystems to exemplify the diversity of these.
5. Marine
The marine ecosystem is with high probability the first ecosystem that existed in the history of life. They are characterized by being present in seas or oceans , with much variation depending on depth, temperature or currents.
The seas and oceans occupy more than 70% of the earth’s surface, so there are an infinity of ecosystems within them.
6. Freshwater
Freshwater aquatic ecosystems are often found surrounded by dry land. We refer to lakes, rivers, or any body of fresh water that is large enough to support life. There are even periodic ecosystems, in bodies of fresh water that disappear depending on the season .
Within this type of ecosystem we find unique and delicate creatures, such as amphibians, which are unable to move away from the water or live in salt water. Pollution of these freshwater ecosystems is a problem, both because it poisons our own drinking water supply and because of the loss of vulnerable freshwater species.
7. Coral reefs
Coral reefs are a subtype of marine ecosystem. Corals are invertebrates that live in colonies, covered by calcium carbonate. These colonies are a perfect environment for various marine species to converge, sheltering approximately 25% of known marine species .
Coral reefs are also currently in great danger of disappearing due to human action (pollution, accidental destruction of corals, changes in the environment such as acidification or increased temperatures…). 91% of coral reefs are found in the Indo-Pacific zone of the oceans.
8. Hydrothermal vents
Hydrothermal vents are areas of the ocean floor where, due to geological processes, there is constant geothermal activity near the seabed. This geothermal activity and the products such as sulfur that are released by fumaroles feed bacteria capable of living thanks to the energy and materials released by them.
These bacteria are the basis that sustains this type of ecosystem, where light does not reach and food is scarce. Even so, near hydrothermal vents we see not only bacteria but also molluscs and crustaceans . They are an example of how life is able to adapt to the most abject conditions.
Bibliographic references
- La Notte, A., D’Amato, D., Mäkinen, H., Paracchini, ML, Liquete, C., Egoh, B., … Crossman, ND (2017). Ecosystem services classification: A systems ecology perspective of the cascade framework. Ecological Indicators, 74, 392–402. doi:10.1016/j.ecolind.2016.11.030.
- Dick, GJ, Anantharaman, K., Baker, BJ, Li, M., Reed, DC, & Sheik, CS (2013). The microbiology of deep-sea hydrothermal vent plumes: ecological and biogeographic linkages to seafloor and water column habitats. Frontiers in microbiology, 4, 124. doi:10.3389/fmicb.2013.00124.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.