Biomanipulation Biomanipulation Biomanipulation is the deliberate alteration of an ecosystem by adding or removing species, especially predators. Changing the fish population of bodies of water as a part of watershed management can facilitate desirable changes in aquatic ecosystems suffering from eutrophication characterized by domination by phytoplankton aiding ecosystem restoration, an application of restoration ecology. In ponds or lakes alternative stable conditions, one with high algae populations, little other plant life, and turbid water, another with low algae populations, a diverse plant population, and clear water, may exist. In addition to prevention of excess nutrients such as phosphorus and nitrates, removal of
Plant physiology gravity or sunlight, is called a tropism. A response to a nondirectional stimulus, such as temperature or humidity, is a nastic movement. Tropisms in plants are the result of differential cell growth, in which the cells on one side of the plant elongates more than those on the other side, causing the part to bend toward the side with less growth. Among the common tropisms seen in plants is phototropism, the bending of the plant toward a source of light. Phototropism allows the plant to maximize light exposure in plants which require additional light for photosynthesis, or to minimize it