Ecosystem Near You

Ecosystem Diagram of a Pond

Biotic: Fish, turtles, ducks, frogs, insects, algae, plants, phytoplankton, bacteria, fungi

Abiotic: rocks, water, sunshine, rain, shade, pH, sediment, oxygen, carbon dioxide, nitrogen,

temperature

A pond ecosystem consists of different tiers, with the water forming the foundation of the

ecosystem. These levels are dependent on the other for health and growth, as ecosystems have

living and nonliving parts. The living, or biotic part, of an ecosystem is known as the ecological

community. Living things interact with each other by feeding on one another. Therefore, energy,

compounds, and chemical elements are transferred from creature to creature along the food

chains.

The surface habitat, as pictured to the right, is located on

the top of the pond water. It is the habitat of air-

breathing floating animals (various insects), and animals

that have adapted to allow them to walk on the surface

of water without breaking through such as water striders.

Some insects and free-floating animals are adapted to

live only on the upper side of the surface film. The animals that dwell on the surface usually feed

on plants, insects, and other animals that may have been killed or drowned and floated to the

surface. The surface dwelling animals may even feed on one another. Other animals, along with

the larvae of some beetles and flies spend much of their life on the underside of the film beneath

the floating plants.

This picture of the open-water area mainly

consists of the water surrounded by plant

life. It ends where vegetation is dense and

rooted into the soil. The open water habitat

is composed of large, free-swimming

organism such as fish, and small

microscopic plants and animals called

plankton that drift suspended in the water. Phytoplankton (small suspended plants), mostly

consisting of algae, are the basic food in lakes. Small suspended animals such as tiny

crustaceans, insect larvae, and other invertebrates called zooplankton also live in the open-water

habitat and are basic food for pond animals. The availability of plankton varies

from season to season, but are most abundant during the spring.

Other animals such as turtles, birds, ducks (pictured), and larger fish come to

the open-water area for food. Some insects, insect larvae, and crustaceans

migrate from the bottom towards the surface, but return to the bottom as

daylight appears.

Life in the bottom habitat of a pond depends upon

the type of bottom a pond may have. For example, if

the pond is

shallow and

has a sandy

bottom it

could be inhabited by sponges, earthworms, snails (as

seen in the picture on the left) and insects. The picture to

the right shows the bottom of a quiet, standing water pond and is characterized as muddy or silty.

The life represented in these types of ponds are crayfish, and the nymphs of mayflies,

dragonflies, and microorganisms. These animals usually burrow into the bottom muds.

Food chains group organisms into trophic levels. A trophic level includes all the organisms in a

food chain that are the same number of steps away from the original source of energy. Therefore,

green plants are in the first trophic level and plant eating animals (herbivores) are placed in the

second level. The third trophic level consists of carnivores (meat eating animals) that feed on

herbivores. The fourth trophic level consists of carnivores that feed on the animals from the third

trophic level, etc.

For example, trophic levels that exist within the pond community are diagrammed as follows:

(1) First Trophic Level = Producers—green plants such as phytoplankton, algae, microscopic

plants, pond lilies, etc. which manufactures food through photosynthesis.

(2) Second Trophic Level = Primary Consumers—herbivores such as mayflies, tadpoles, small

crustaceans, nymphs, and certain types of beetles that feed on the plants in level one.

(3) Third Trophic Level = Secondary Consumers—carnivores such as fish and frogs who

consume plants and animals from the first and second trophic levels.

(4) Fourth Trophic Level = Tertiary Consumers – ducks, birds

Disturbances such as drought or a fire can greatly affect the pond's ecosystem by causing many

plants and animals in the area to perish. In a drought, the area of the pond may decrease in size

causing many plants to die, which in turn causes the whole ecosystem downline to diminish. If a

fire occurs, it will burn trees and bushes that birds and other animals live in, negatively

impacting the pond. A fire can also have the potential to cause increased runoff of rainfall which

may reduce water quality.