Interesting Food Webs

In terrestrial (land) ecosystems, plants are the primary producers. This is what you probably think of when you think of producers.

But in aquatic (water) ecosystems, phytoplankton and other algae are the primary producers. Believe it or not, half of the photosynthesis performed on Earth is done by phytoplankton!

Phytoplankton are plant-like algae and members of Kingdom Protista. Phyto- means plant Although these microscopic organisms are too small be seen individually, they can reproduce to such enormous numbers that groups of them can be seen by satellites!

Chemosynthesis Deep in the ocean, there is no light for photosynthesis to occur. But in the 1970s, scientists found entire food webs living near underwater hydrothermal vents which spew minerals and provide heat.

Chemosynthesis Scientists found bacteria that were performing chemosynthesis by obtaining energy from inorganic compounds like hydrogen sulfide (H2S) instead of light. Photo by Adrian Hetzer These bacteria use this energy and CO2 to produce the organic compounds needed in the food web.

Chemosynthesis These chemosynthetic bacteria are the producers in these deep underwater ecosystems, and they often live symbiotically inside larger animals like the tube worms shown to the right. Photo by Adrian Hetzer Photo by Achim Raschka

Detritus Other ecosystems are built around non-living organic matter, called detritus. This organic matter is made up of dead plants and animals, along with the solid waste of animals.

Detritus Compost piles support a large variety of decomposers, like bacteria and fungi, along with animals that eat the detritus (called detrivores).

Detritus and Cave Ecosystems In the darkest parts of caves, where no light reaches, some animals live their entire lives in the dark. These are called troglobites. Cave Snail Troglobites rely on organic material brought into the caves by bats and other animals. Photo by Magnus Manske

Detritus and Cave Ecosystems Bat feces (guano) and the remains of dead bats and animals forms detritus in caves. Decomposers and detritus are the foundation of the food chain, and detrivores and carnivores complete the food chain.

Detritus and Cave Ecosystems Even though cave ecosystems exist in the dark, they still depend on the plants and photosynthesis. Without plants, there would be no energy or organic matter for bats to bring back into the dark of the caves!