HANDOUT:
Topic # 3073
WATER TESTING FOR AQUACULTURE SYSTEMS
Created by Edward C. Meisel III
Introduction:
You should work in teams to create an aquaculture system that will prepare an animal
species of your choosing to be ready for the market. In the process, comparisons will be
drawn between natural ecosystems and a controlled aquaculture system in terms of the
amount of energy necessary for animal growth (energy flow), the mechanisms for the
acquisition of food and the breakdown of waste (material cycling), and complexity of the
systems. You as students will engage technology to replicate natural biotic and abiotic
components in a simple artificial environment.
Goals:
1. Create an operational aquaculture system
2. Understand energy flow in ecosystems and its relationship to raising animals in
artificial systems.
3. Understand material cycling in ecosystems and its relationship to raising animals
in artificial systems.
4. Using technology, develop methods to mimic natural processes in artificial
environments
Related Topics:
 Hydroponics
 Waste water treatment
 Math/Physics - rates, volumes, surface area/volume ratios
 Anatomy, physiology, nutrition
 Economics - supply and demand, cost effectiveness
Guiding Questions:
1. Describe the path energy takes as it flows through a natural aquatic habitat or
community. Review materials on trophic level structure and energy flow
efficiency. Draw a typical trophic level chart.
2. What is the efficiency of energy transfer from one trophic level to the next? How
will this affect the operating efficiency of an artificial habitat such as an
aquaculture tank?
3. How do materials cycle through a natural aquatic habitat? Construct a simple food
web showing the relationship between producers, herbivores, carnivores,
omnivores, and detritivores (decomposers).
4. How will materials cycle through an aquaculture unit? Will the cycle be simpler
or more complex than a natural system? What part of a food web or trophic level
will be most heavily represented in an aquaculture?
5. How will the cycling be different for a recycling system as compared to a flow
through system?
6. From the questions above, examine the areas in an aquaculture system that you
think will be different from a natural aquatic system. For each different area,
brainstorm some possible technological solutions to make the artificial
(aquaculture) system act as much like the natural system as possible.
Sample Responses:
1. Sun > Plants (Producers - Phytoplankton, Algae, Submerged vascular) >Primary
(1o) Consumers > Secondary (2o) Consumers > (3o) Consumers
2. 10% of energy stored in one trophic level is (on average) transferred to biomass
storage in the next trophic level. Feed costs, rate of growth, profit margin
3. Food webs cycle materials within the habitat. Some materials enter the system
from other habitats and some materials are lost to other habitats.
4. In most cases, materials (primarily nutrients) will be added from outside the
system. Consumer biomass will be very high, producing a great deal of waste.
Some waste materials will have to be extracted and other waste materials will
have to be processed by detritivores.
5. In a flow through system, inputs and outputs will be much higher.
6. For an artificial system, such as an aquaculture system (especially enclosed
recycling systems):
 Sun may or may not be the source of energy.
 Producers as a nutrient source may be non-existent.
 Substrates and other abiotic structures may not be present for shelter or as
habitats for decomposers and other life forms.
 Turbulence and currents may not provide enough dissolved oxygen.
 Size of habitat will be extremely limited - "edge effect" will be
pronounced