water and the aquaponics system - dornsife.usc.edu and the aquaponics system food for thought: k-12...
TRANSCRIPT
Water and the Aquaponics System
Food for Thought: K-12 Aquaponics Program
Linda Chilton
USC Sea Grant Education Programs Manager
April 2017
Objectives of this lesson
� Reflect on the role water plays in supporting life on our planet and more specifically in food supply
� Learn the importance of preparing the water in your aquaponics system and how to monitor the health or quality of the water
� Begin to explore the flow of water in the system
� Begin to explore the relationship between water and food justice
Aztecs farmed “floating” islands
Chinampas today
� rice fields + fish + birds that began as early as 6th century in Southern China
Similar farming practices today
What do you notice is similar between these three systems?
Hydroponics – Large scale plant production with nutrient solution and without soil
Aquaculture Large scale fish, crab, lobster, snail and clam farming
� Aquaculture + Hydroponics = Aquaponics � Aqua: from Latin for water � ponics: from Greek, to work or labor; refers to
roots growing in water, without soil
Aquaponics
Aquaponics
� raise both animals and plants � nutrients produced are used
by the system � everything cycles � less water, less power needed
• less expensive then hydroponics • creates natural nitrogen balance
� Plants
� Microbes
� Fish
� Pump
Why Do They Need Water?
Water Circulation
� Using the large sheet of paper create a model of water circulation in your tank. How does water move through the system? Remember to label all of the processes and interactions.
Talk With Your Partner
� Discuss how you can decide which water to use to put into your system? ¡ Can you use water from the tap? ¡ From the hose? ¡ Do you need bottled water? ¡ Do you need special water? ¡ Can you use LA River water?
� How can you be certain the water is healthy for your aquaponics system and the life in your system?
� Clear water doesn’t always equal healthy water!
Talk With Your Partner
Water Test Kits
� Used to measure water quality – the health of the water. The water test kits use reagents that are added to the sample of water to find the levels of important parameters of:
- dissolved oxygen - nitrite - nitrate - alkalinity - ammonia - temperature - pH
• Oxygen is essential to support healthy fish, roots, and microbes. • Dissolved oxygen is measured in parts per million (PPM) or milligrams/liter (mg/l). Oxygen levels change rapidly once a sample is taken from the system. • Temperature, pressure and elevation all effect how much oxygen can stay dissolved in water.
• Pumps and splashing water increase oxygen availability. • Less oxygen stays dissolved in warmer water
Dissolved Oxygen
http://www.teamorca.org/
pH (potential Hydrogen)
� amount of free hydrogen or free hydroxyl ions (how acidic or basic a solution is respectively).
� pH impacts ¡ plants ability to absorb nutrients ¡ animal and microbe health
� The pH scale is 0 – 14 with 7 as neutral; ¡ plants do better at a lower pH
� The amount of salts (softness or hardness of the water) effects the stability the pH of the water.
Acidic
Basic
Neu
tral
Temperature
� Water temperature ranges for fish and microbes must be monitored
� Different species of fish, have different temperature needs based on their native habitat
species Trout Tilapia Goldfish
Thriving temperature (surviving temperature)
55 – 65oF
(38-68°F)
74 – 80oF
(60-95°F)
65 – 75oF
(45-90°F)
� Temperature effects: ¡ the ability of bacteria to convert ammonia to nitrates that can be used by plants
¡ Oxygen availability in water for fish, roots, microbes
� Time of day, heat of the room can both effect temperature. � Most fish can handle wide temperature changes over several
hours but not rapid changes.
Temperature
Measuring Nitrogen
� Nitrogen can be found in three forms in your system so we measure all three ¡ Ammonia – from fish wastes and decomposition; high levels
can be deadly to fish ¡ Nitrite – after bacteria convert the ammonia to nitrite; still a
problem for fish ¡ Nitrate – a form of nitrogen plants can use to grow and not
harmful to fish in limited amounts
Changes in Water Quality
� What might change in your system from morning to afternoon that would change water quality?
� What other clues can you use to tell the water quality is
changing, before you do a test?
� As we look how does this project effect the world in which we live, we are looking at an alternative to conventional farming.
� 70% of freshwater used goes to agriculture � Roughly 30% of the food produced worldwide (about 1.3 billion
tons) is lost or wasted every year, which means that the water used to produce it is also wasted
� When we look at water on a world scale, water scarcity directly impacts food security
� Global food and nutritional security, requires producing more nutritious food with less water
� Aquaponics is one alternative to conventional farming that uses significantly less water.
Water & Food Production
�
Linda ChiltonEducation Programs Manager
USC Sea Grant
Questions?
Thanks for a productive day!