ABIOTIC FACTORS: CHARACTERISTICS, CLASSIFICATION AND EXAMPLES - ENVIRONMENT - 2025

The abiotic factors are the components that make up lifeless biotope or physical space where life takes place in the ecosystem. This includes the physical environment (soil, water and air), and all physicochemical components and related factors, outside of living things.

In this sense, the climate and its variables, as well as the properties of the soil and water, are part of the abiotic factors. The term abiotic arises in the framework of the analysis of the ecosystem, as opposed to the biotic (living components of the ecosystem).

Abiotic factors scheme. Sun, air, land and water are abiotic factors. Source: Abby Moreno

The study and characterization of the abiotic environment is carried out in relation to the role they play in sustaining life, thus shaping the ecosystem. The particular composition of abiotic factors in an ecosystem determines the species of living organisms that comprise it.

Abiotic factors can be classified into serum factors and ecogeographic factors, the former being linked to the relationship of the planet with outer space. While ecogeographies cover all the factors inherent to planetary environments (crust, water and air).

Examples of sidic factors are the Sun, the Moon, meteors and asteroids, gravity, rotational and translational movements, and atmospheric pressure. While in ecogeography there are meteorological factors such as wind, rainfall and temperature as well as the soil.

Characteristics of abiotic factors

Devoid of life

The main characteristic of abiotic factors is their lack of life, that is, they are not self-programmed systems, nor capable of metabolizing. Its interaction with the rest of the components of the planet is passive.

Complex relationships

Abiotic factors are also characterized by being interrelated, forming a complex system at the planetary and even universal level. Its existence and dynamics are governed by physical and chemical laws, without any biological property, although influenced by biotic components.

Determine the biotic components

Depending on the specific combination of abiotic factors, expressed through specific magnitudes of their variables, there will be a certain biotic community.

Types of abiotic factors (classification)

The abiotic factors of the planetary ecosystem can be classified in principle into two large groups

• The cider, which are those factors that are the product of the Earth's relationship with its external environment.
• The ecogeographic ones, which cover all the factors and processes proper to the functioning and structure of the planet itself.

In turn, in each case there are physical and chemical factors in constant interrelation, which are defined by establishing the magnitude of certain variables. There are variables common to almost all ecosystems, such as solar radiation, temperature, pH and salinity.

Others are more specific, such as the depth and concentration of dissolved oxygen in water in aquatic ecosystems. Some are part of the dynamics of the ecosystem such as fire in the savannas and the Mediterranean forest.

- Serum factors

As a planet in the solar system, Earth's ecosystems are influenced by a number of external factors, including the gravitational forces established between the Earth, the Sun and the Moon.

Similarly, there are processes influenced by the movements of rotation and translation that the Earth makes. While others are more random like the occasional meteor and asteroid collision.

Solar radiation

The fundamental energy source of every terrestrial ecosystem is the radiation emitted by the Sun and reaches the Earth through its atmosphere. This provides energy for most of the terrestrial processes, among them photosynthesis and the thermal regulation of the planet.

Solar radiation. Source: kein

A planet at a greater or lesser distance from the Sun than the current one, would not have allowed the development of life as we know it. On the other hand, the conformation of the planet determines a differential incidence of solar radiation, depending on the latitudinal location of each ecosystem.

Gravity and tides

The relationship between the gravitational force of the Earth, the Moon and the Sun determines processes such as tides, which are fundamental for coastal ecosystems.

On the other hand, Earth's gravity makes possible the existence of the atmosphere that surrounds the planet. The specific composition of this atmosphere and its evolution, in turn, made possible the evolution of life on the planet.

Earth's rotation

The rotational movement that the Earth makes on its axis influences the regime of winds and marine currents. This in turn is decisive for meteorological processes and all together for life on Earth.

Rotation of the Earth. Source: Apollo 17

Similarly, this movement establishes the duration of day and night, defining the photoperiod or hours of light. This process affects photosynthesis and flowering in plants as well as the habits of living beings in general.

- Ecogeographic factors

Terrestrial ecosystems are a complex matrix of abiotic factors forming a biotope or living space. This includes soil, air, and water and all of their physical and chemical components and processes involved.

Atmospheric and meteorological factors

Among the abiotic factors are the component gases of the atmosphere, as well as the variables that affect them such as temperature, atmospheric pressure and winds. Like precipitation, relative humidity and the concentration of solid particles in suspension.

Edaphic factors

The soil or surface layer of the lithosphere is the basis of support for terrestrial ecosystems, serving as anchor and nutrition for plants. Among the variables that are part of the abiotic factors of the soil are its structure, its texture, its chemical composition and water content.

Geographic factors

From a geographical point of view, there are a series of abiotic factors that influence the diversification of ecosystems. Among them, latitude, longitude and altitude that determine other variables such as meteorological and edaphic.

Thus, the differences in the conditions of the ecosystems of the intertropical zone with respect to the temperate or polar ones are notable. In the same way, the differences between the ecosystems in valleys and plains compared to those in high mountains.

Geological factors

Due to the interaction of the lithosphere with the deep layers of the mantle (asthenosphere), geological processes occur that affect life. These abiotic factors are manifested through tectonic movements, shifts of the Earth's plates and volcanic eruptions.

These tectonic movements in turn determine the relief, affect the temperature, the composition of the environment and other variables. On the other hand, the composition of the bedrock in the earth's crust is an important abiotic factor in the formation of the soil.

Hydrological factors

Most of the Earth's surface is covered by water, especially forming oceans, with a great variety of aquatic ecosystems. Water as an environment is made up of a first order abiotic factor with its components, variables and characteristic processes.

Water. Source: Manfred Morgner (ka-em-zwei-ein)

In turn, these abiotic factors will vary whether they are freshwater ecosystems (limnological factors), marine (oceanographic factors) or glacial areas (glaciological factors). In each case, variations in salinity, temperature, depth, among others, are decisive.

Examples

- Floors

Floor. Source: HolgerK at English Wikipedia

Soil is an example of the variability that an abiotic factor can achieve, in turn influencing the variability of ecosystems. Depending on its structure, texture, fertility, moisture and organic matter content, the soil plays a determining role in the dominant vegetation.

Aridisols

The arid soils, with a sandy texture, high permeability and low fertility, support little vegetation. In this way, a semi-desert or desert landscape is formed, with little biodiversity.

Acid soils

A soil with a high content of aluminum ions in solution becomes toxic to most vegetation. In general, acidic soils make plant nutrition difficult, so its plant cover is low.

Fertile soils

In contrast, fertile soils allow the development of large amounts of plant biomass, supporting ecosystems with a large amount of life. Such is the case with molisols in prairies or podsoles in deciduous forests.

- Ecosystem variation and altitude

When ascending a high mountain, a gradual change of vegetation is observed from the plain to the top. This is more marked in the tropics and subtropics, and has to do with the decrease in temperature at higher altitudes.

Additionally, plants at high altitudes are exposed to stronger winds, thus reducing their height. All of this forms an ecosystem gradient along the altitudinal transect.

- The high mountain of the tropical Andes

In the high mountains of the tropical Andes, there are grasslands and deciduous forests in the foothills. As you climb, semi-deciduous forests develop, followed by evergreen humid forests.

Then there are the cloud forests, which in turn are divided into altitudinal strips with a lower and lower upper canopy. Finally the tall shrubland dominates, and then gives way to the shrubby and herbaceous moor.

In the highest peaks practically all vegetation disappears, finding mosses and lichens. Here the determining abiotic factors are altitude and associated temperature, as well as available humidity.

- Ocean depth, light, temperature and life

In oceanic ecosystems, the most relevant variables are salinity, light, temperature and depth. This last abiotic factor, together with latitude, determines the behavior of temperature and light on a vertical gradient.

As we descend to the depths of the sea, the availability of light decreases and the temperature drops. That is why most of the marine life develops in the first 200 m of depth.

Furthermore, the surface temperature of the water is also affected by other factors, such as deep sea currents.

- Global warming and ecosystems

A polar bear in full swing, on Spitsbergen Island, Svalbard, Norway. Source: wikipedia.org

A global example of the effect of abiotic factors on ecosystems is the phenomenon of global warming. In this case, the human alteration of the atmospheric balance is bringing as a consequence the increase in the average temperatures of the planet.

This situation impacts on a whole series of abiotic factors at the planetary level. Temperature, wind regimes, marine currents, rainfall are altered, modifying ecosystems and threatening the extinction of many species, including humans.

Abiotic factors of the desert

High temperatures and low rainfall are the main abiotic factors in the desert, which in turn affects the edaphic characteristics. These are sandy soils subjected to high solar radiation due to the scarce vegetation cover and strong winds.

Abiotic factors in the desert. Source:

On the other hand, the temperature variation between day and night is extreme. In this context, erosive processes are intense and extensive, shaping the characteristic landscape of large sandy areas.

Abiotic factors of the rainforest

In the tropical forest ecosystem, the abiotic factors of latitude and altitude are strong determinants of its characteristics. Being located in the tropical zone, these ecosystems present particular characteristics of the rainfall and temperature regime.

In these ecosystems, the abiotic humidity factor reaches high levels, high or relatively low temperatures depending on the altitude with little variation between day and night. In addition, the availability of water is high and therefore also the vegetation cover, which allows soils with better structure and fertility.

In relation to solar radiation, the jungle presents a duality, since in the upper canopy it is received with high intensity, but not inside the vegetation. In the interior of the forest, a gradient of light develops down to the understory.

All this defines the type of life present in these ecosystems, with abundant climbers and epiphytes, as well as large-leaved plants in the understory. While the trees of the upper canopy have hard and small leaves.

Abiotic factors of the temperate forest

In the formation of a temperate forest ecosystem, the abiotic latitude factor comes into play, which in turn determines the seasonal regime. These forests are subject to a four-season regime, with abundant, well-distributed rainfall and moderate temperatures, although they may experience periods of night freezing.

Solar radiation is not as intense as in tropical areas but is abundant for most of the year. The soils are deep and fertile, being able to support a large plant biomass.

Abiotic factors of the tundra

In the tundra biome the main abiotic factors are latitude, temperature, humidity and solar radiation. Since the tundra is located north of the planet in the Arctic Circle, solar radiation is low. Similarly, the prevailing temperatures are low (down to -50 ºC), with long winters and short summers.

Rainfall is low, but humidity is high due to low evapotranspiration, forming wells and swamps, with a poorly oxygenated substrate. The soil has a permanent frozen subsurface layer, the permafrost, made up of semi-decomposed remains of mosses and lichens.

The low temperatures and the substrate do not allow to support high vegetation and high biomass, so mosses and lichens dominate.

Abiotic factors of the savanna

In this case, latitude is also an important factor, as it determines solar radiation, temperature and precipitation. Meteorological processes such as the variations of the Intertropical Convergence establish a bi-seasonal pattern, with a marked dry and rainy period.

The other determining factor is the soil, which in most cases is sandy or clayey. The flat or hilly relief is also an abiotic factor that configures the savanna ecosystem, affecting other factors such as runoff.

Finally, a determining abiotic factor in the ecological dynamics of the savannas is fire. Periodic fires affect the characteristics of the vegetation, for example, the dominant grasses are adapted to survive burning.

References

1. Calow, P. (Ed.) (1998). The encyclopedia of ecology and environmental management.
2. Izco, J., Barreno, E., Brugués, M., Costa, M., Devesa, JA, Frenández, F., Gallardo, T., Llimona, X., Prada, C., Talavera, S. And Valdéz, B. (2004). Botany.
3. Margalef, R. (1974). Ecology. Omega editions.
4. Odum, EP and Warrett, GW (2006). Fundamentals of ecology. Fifth edition. Thomson.
5. World Wild Life (Viewed on January 27, 2020). Taken from: worldwildlife.org/biomes/
6. Zunino, M. and Zullini, A. (2004). Biogeography. The spatial dimension of evolution. Interciencia.