AERIAL ECOSYSTEM: CHARACTERISTICS, TYPES AND ANIMALS - BIOLOGY - 2025

The aerial ecosystem is made up of all biotic (living beings) and abiotic (inert elements) factors that interact in the troposphere. In a strict sense it is a transition ecosystem, since no living organism completes its complete life cycle in the air.

The main abiotic characteristic of the aerial ecosystem is that the substrate in which it develops is air. This is a mixture of gases and therefore a lower density substrate than terrestrial or aquatic.

Cranes (Grus grus) in flight in Spain. Source: Arturo de Frias Marques

On the other hand, the atmosphere is the space where climatic processes take place, especially rainfall, winds and storms.

Although birds dominate par excellence in the air environment, there are also insects and flying mammals. In other animal groups, such as fish and reptiles, there are species capable of gliding flights.

Likewise, plants that present anemophilic pollination (by wind) use the aerial ecosystem as a vehicle to transport pollen. Similarly, many plants disperse their fruits or seeds by air.

General characteristics

Aerial ecosystems are formed mainly in the lower part of the troposphere, which is the lower layer of the atmosphere. This layer reaches a thickness of 16 km at the equator and 7 km at the poles, due to bulging from the earth's rotation.

These ecosystems, unlike the terrestrial and aquatic ones, do not have a permanent biotic component. Therefore, no living organism completes its entire life cycle in this ecosystem and there are no primary producers, so it is not self-sufficient.

Aerial ecosystems have three general characteristics: the substrate is air, it is where climate phenomena develop and the living component is transitional.

- Abiotic components

Among the abiotic components of the aerial ecosystem is air, with the gases that compose it and the water vapor that is incorporated. Additionally, there is a large amount of dust particles in suspension.

The air

It is the component of the troposphere (lower layer of the atmosphere), directly in contact with the earth's surface. Air is mainly composed of 78.08% nitrogen and about 21% oxygen, plus CO2 (0.035%) and inert gases (argon, neon).

Density

Air density decreases with height and temperature, which assigns an important differential characteristic between aerial ecosystems. Thus, in high mountain areas the air will be less dense compared to areas at sea level.

Likewise, air masses over desert areas decrease their density during the day (high temperatures) and increase it at night (low temperature).

Temperature

The troposphere heats up from the bottom up, because air is generally invisible to ultraviolet radiation from the Sun. This radiation hits the Earth's surface and heats it, causing it to emit infrared radiation or heat.

Part of the radiation escapes into outer space, another is retained by the greenhouse effect of some gases in the atmosphere (CO2, water vapor).

Air temperatures are less stable than those of land and water, varying with wind currents and height. As the troposphere rises, the temperature decreases at a rate of 6.5 ºC / km. In the upper part of the troposphere (the tropopause), the temperature drops to -55 ºC.

Humidity

As part of the water cycle in its evapotranspiration phase, water in the gaseous state or water vapor is incorporated into the atmosphere. The amount of water vapor present in the air (relative humidity) is an important characteristic of the different aerial ecosystems.

The air in desert areas has a relative humidity of around 20% at noon and 80% at night. While in the air in the tropical rain forest a humidity of 58-65% is detected at noon and 92-86% in the early morning.

The winds

Air currents. Source: The original uploader was Ellywa at Dutch Wikipedia.

The differences in temperature produced by the movements of the Earth in relation to the Sun, generate differences in atmospheric pressure between regions. This causes the air masses to move from the high pressure areas to the low pressure ones, generating the winds.

Rains and storms

The troposphere is the domain of climatological phenomena, including the accumulation of water vapor clouds. The evaporated water rises with the hot air masses and as it cools it condenses around particles in suspension, forming clouds. When the condensed water load reaches a critical point, rain occurs.

Storms, hurricanes, tornadoes

Another disturbance that affects the aerial ecosystem are storms, which in some cases become hurricanes with strong winds and torrential rains. Storms are meteorological phenomena that happen when two air masses with different temperatures face each other.

In other cases tornadoes are formed, which are columns of air rotating at very high speed whose vertex comes into contact with the earth.

Dust particles

Another abiotic component of the aerial ecosystem is dust (small material particles in suspension). Winds and evaporation drag particles from the surface of the earth and bodies of water into the troposphere.

Saharan dust. Source: Geological Image Bank

For example, annually a cloud of dust from the African deserts moves annually to America. It is about hundreds of millions of tons of dust that cross the Atlantic Ocean and are deposited in different places in America.

The concentration of dust from the Sahara in some parts of America can reach 30 to 50 micrograms per cubic meter.

- Biotic components

As noted, there is no living being that completes its entire biological cycle in the aerial ecosystem. However, the presence of a great diversity of terrestrial and marine microorganisms in the troposphere has been detected.

Bacteria, fungi and viruses

Suspended bacteria, fungal spores and viruses have been detected in air samples taken by NASA planes. In this sense, studies are being carried out to determine if some species of bacteria are capable of carrying out metabolic functions in that environment.

Bacterium. Source: NIAID

Bacteria are carried off the sea surface or carried along with land dust by winds and rising hot air masses. These bacteria live in dust particles and suspended water droplets.

Pollen and spores

Other living components that pass through the aerial ecosystem are pollen grains and spores. Spermatophytes (seed plants) carry out their sexual propagation through the fusion of the pollen grain and the ovule.

Pollen grains. Source: Dartmouth College Electron Microscope Facility

For this to happen, the pollen grain (male gamete) must travel to the ovum (female gamete). This process occurs either by the wind, by animals or by water.

In the cases of pollination by wind (anemophilous) or by flying animals (zooidiophilic), pollen becomes a transitory part of the aerial ecosystem. The same occurs with the spores that make up the propagation structure of ferns and other seedless plants.

Animals

There are a large number of animals that have adapted to enter the aerial ecosystem. Among these are flying birds, flying insects, flying mammals, flying reptiles, and even flying fish.

Types of aerial ecosystems

Approaches to the air environment as an ecosystem are scarce and in that sense there are no classifications that differentiate types of air ecosystems. However, in the context of the troposphere there are differences between regions, both in the latitudinal and longitudinal sense, as well as vertically.

Latitudinal zoning

The aerial ecosystem varies in altitude, pressure and temperature between the equator and the poles. Similarly, it varies depending on whether the column of air is over the land or over the sea.

Therefore, the living beings that pass through the aerial ecosystem vary, depending on the region where the air column is located.

Vertical zoning

As you ascend in the troposphere, the abiotic conditions of the aerial ecosystem also vary; the temperature decreases as does the density of the air. In the first 5,000 meters above sea level, the aerial ecosystem has the incursion of birds and some insects.

For their part, the rest of the animals only interact in this ecosystem at the height of tree canopies. In addition, bacteria and fungal spores are found in the aerial ecosystem above 5,000 masl.

At the same time, a territorial zoning is manifested, finding that species of terrestrial bacteria predominate on land and marine bacteria on the sea.

Animals of the aerial ecosystem

There are diverse animal groups capable of flying or at least gliding in order to venture through the air. Although some can stay up to months flying, all have at some point to leave this ecosystem to feed, rest or reproduce.

- Birds

There are about 18,000 species of birds in the world, most of which are capable of flying. Birds not only move through the air, many hunt their prey in flight and even fulfill part of their reproductive cycle.

King Swift (

This species is able to stay in flight for months and according to a study carried out, it can stay in the air for up to 200 continuous days.

King Swift (Tachymarptis melba) in flight. Source: Birdwatching Barcelona

Studies are continuing to determine how this bird manages to stay in the air for so long and especially if it is able to sleep in flight. The king swift does not need to stop to eat, as it feeds on insects that it catches in mid-flight.

Albatross (Diomedeidae)

Albatross. Source: Duncan Wright

They are a family of seabirds very efficient in gliding flight, which is widely spread throughout the world. Among its species is the traveling or wandering albatross (Diomedea exulans), which reaches an average wingspan of 3 m.

Gray-headed albatrosses (Thalassarche chrysostoma) fly 950 km per day from southern Georgia, circling Antarctica. These birds take 46 days to complete their journey.

- Insects

Insects are the largest animal group that exists, both in species and population size. Many species of insects are flying, including bees, wasps, flies, mosquitoes, beetles, lobsters, and others.

The bee (Anthophila)

Bee visiting flower (Source: pixabay.com/)

Bees are highly valued insects due to their honey production and their role in pollinating plants. The most common species in the beekeeping industry (honey production) is Apis mellifera.

They are social insects and the workers make constant trips long distances looking for pollen and nectar. Bee species have different flight ranges, that is, the maximum distance from which they manage to return to their nest.

In Melipona sp. the maximum distance recorded is 2.1 km while for Bombus terrestris it is 9.8 km and in Apis mellifera it is 13.5 km. However, the maximum recorded is 23 km, reached by the Euplusia surinamensis species.

The lobster (Acrididae)

This family of insects includes about 7,000 migratory species that eventually form huge populations and become pests. They travel many kilometers in large swarms, devouring the crops and other plants they find in their path.

- Mammals

Among the mammals that enter the aerial ecosystem, the bats (Chiroptera) stand out. These are the only mammals that perform active flight (with the impulse of their wings).

There are other passive flight or gliding mammals such as the Siberian flying squirrel (Pteromys volans) or the Central American squirrel (Glaucomys volans).

Among rodents there are also gliders such as those of the genus Idiurus and in other groups such as the dermoptera or colugos (placental mammals) and the petáurids (marsupials).

- Reptiles

Some Asian species that have developed the ability to flee fleetingly through the aerial ecosystem. They do this by jumping out of trees and flattening their body to twice their normal width and they manage to glide even better than flying squirrels.

- Fishes

There is a group of so-called flying fish (Exocoetidae) capable of temporarily entering the aerial ecosystem to escape from their predators. It is about 70 species that have adequate tail fins to propel them out of the water.

Flying fish (Cheilopogon melanurus). Source: Patrick Coin (Patrick Coin)

From this momentum these fish can glide a distance of around 50 m, reaching speeds of up to 60 km / h. This ability to glide is thanks to their unusually large pectoral fins.

References

1. Calow, P. (Ed.) (1998). The encyclopedia of ecology and environmental management.
2. Greensmith, A. (1994). Birds of the world. Omega editions.
3. Ludwig-Jiménez, LP (2006). Observation of flight ranges of Bombus atratus (Hymenoptera: Apidae) in urban environments. Colombian biological record.
4. Lutgens, FK, Tarbuck, EJ, Herman, R. and Tasa, DG (2018). The atmosphere. An introduction to Meteorology.
5. Margalef, R. (1974). Ecology. Omega editions.
6. Purves, WK, Sadava, D., Orians, GH and Heller, HC (2001). Life. The science of biology.