Water pollution Oxygen-depleting substances may be natural materials such as plant matter (e.g. leaves and grass) as well as man-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species. Alteration of water's physical chemistry includes acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions
Dispersal vector excess algae and non-native plant growth. Eutrophication can lead to decreased long distance dispersal because the lack of nutrients to native plants causes a decrease in seed release height. However, because of the lowered release height, eutrophication can sometimes lead to an increase in short distance dispersal. Climate change effects on wind patterns have the potential increase average wind velocity. However, it can also lead to lower levels of wind dispersal for each individual plant or organism because of the effects climate change has on the normal conditions needed for plant growth, such as temperature and rainfall. Hydrochory is dispersal