Chemosynthetic Food Web
Introduction
The struggle for food is
one of the most
important and complex
activities to occur in an
ecosystem. To help
simplify and understand
the production and
distribution of food
within a community,
scientists often construct
a food web, a diagram
that assigns species to
generalized, interlinked
feeding levels. Each layer of the web represents a particular role in the movement of organic energy through the
community.
Despite their unusual nature, faunas based on chemosynthesis are tied together by food webs similar to those of
better-known communities. The hydrothermal vent food web below has four layers:
Primary producers are the original source of food in the vent ecosystem, using chemical energy to
create organic molecules. All other life depends on primary producers, and they have the greatest
biomass in the community.
Primary consumers get their energy directly from the primary producers by eating or living
symbiotically with them.
First order carnivores prey on the primary consumers and in turn are eaten by other animals.
Top order carnivores eat other consumers and carnivores but are rarely hunted by other creatures.
Because they are separated from the primary food production by several layers, top order carnivores
have the smallest biomass in the food web.
Instructions – Complete and answer all questions in complete sentences.
1. In your groups read through all of the Organism ID cards. All of the Organisms belong to the same
deep sea hydrothermal vent community. Place cards into three groups; producers, consumers, and
decomposers, and then record your findings below.
Producers
Consumers
Decomposers
2. Now break those groups down into Primary Producers, Primary Consumers, First-order Carnivores, and
Top-order carnivores. (If you are not sure how to do this review the definitions at the top of the page.)
Primary Producers
Primary Consumers
First-order Carnivores
Top-order Carnivores
3. Next, draw a food web for the ecosystem using all 17 organisms.
Answer the following questions.
a. How does this ecosystem create energy (carbohydrates)?
b. What happens if one producer is removed from the food web?
c. What happens if one consumer is removed from the food web?
d. What happens if one decomposer is removed from the food web?
e. Why is it important for humans not to interfere with even one species in a food web?
4. Now identify 10 different food chains from your food web. Label each organism T1 for trophic level 1,
T2 for trophic level 2, and so on.
Ex. Vent bacteria (T1) Vent shrimp (T2) Vent Octopus (T3)
5. Finally, create a trophic pyramid that includes all 17 organisms of the hydrothermal vent community.
6. Critical Thinking Question
Marine scientists were stunned to find complex ecosystems based on chemosynthesis flourishing around
deep-sea hydrothermal vents. This discovery also caught the attention of space scientists, giving them
renewed hope that they might find life elsewhere in the solar system. Explain why chemosynthesis may be
more likely to support life on distant worlds than photosynthesis.
(Answer this question on the back of this piece of paper – fill up the entire sheet!!)