Sustainable Gardening -updates for 501 & 502 3/21/20 Greenhouses Hydroponics systems Water and nutrients were added 3/21 Notice that as the plants get bigger, the density of plants per area becomes more important. There is no algae growth in the container. Aquaponics systems Reduction of water plants – all 4 systems had an incredible growth of their water plants. The fish no longer had enough space to swim and get to the top for food. I removed half of each plant and replaced the top. All systems, added water and fish were fed (3/18 and 3/21) These 3 systems are clear and thriving. This system, however, went through a change called an algal bloom. In an algal bloom all of the oxygen is used up rapidly as the algae and bacteria multiply faster than the system can handle. I drained the water from the system and replaced it with new. An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater More about Algal Blooms Algal bloom concentrations may reach millions of cells per milliliter. Colors observed are green, yellowish-brown, or red. Some algal blooms are the result of an excess of nutrients (particularly phosphorus and nitrogen) into waters and higher concentrations of these nutrients in water cause increased growth of algae and green plants. As more algae and plants grow, others die. This dead organic matter becomes food for bacteria that decompose it. With more food available, the bacteria increase in number and use up the dissolved oxygen in the water. When the dissolved oxygen content decreases, many fish and aquatic insects cannot survive. This results in a dead area.