Eutrophication may only be made available again during autumn turn-over or in conditions of turbulent flow. Enhanced growth of aquatic vegetation or phytoplankton and algal blooms disrupts normal functioning of the ecosystem, causing a variety of problems such as a lack of oxygen needed for fish and shellfish to survive. The water becomes cloudy, typically coloured a shade of green, yellow, brown, or red. Eutrophication also decreases the value of rivers, lakes and aesthetic enjoyment. Health problems can occur where eutrophic conditions interfere with drinking water treatment. Human activities can accelerate the rate at which nutrients enter ecosystems. Runoff from agriculture
Plant to plant communication via mycorrhizal networks reported to move via an AM network between conspecific plants. Workers believe that transfer of nutrients by way of mycorrhizal networks could act to alter the behavior of receiving plants by inducing physiological or biochemical changes, and there is evidence that these changes have improved nutrition, growth and survival of receiving plants. Several mechanisms have been observed and proposed by which nutrients can move between plants connected by a mycorrhizal network, including source-sink relationships, preferential transfer and kin related mechanisms. Transfer of nutrients can follow a source-sink relationship where nutrients move from areas of higher concentration to areas of lower