Como o desenvolvimento humano afeta a relação entre os nutrientes e turbidez e o biovolume de cianobactérias?

Abstract

Human activities cause drastic changes in the functioning of ecosystems, such as the reduction of biodiversity. Phytoplankton are among the first to respond to these changes. Eutrophication can cause cyanobacterial blooms and select species with different functional traits, according to hydrodynamic conditions (e.g. water residence time - TR) and luminous availability. The effects of the Human Influence Index (IIH) and RT on the magnitude of the relationship between environment (phosphorus, nitrogen and turbidity) and biovolume of the functional morphological groups (GFBMs) of cyanobacteria III, VII and VIII. Phytoplankton from Brazilian lakes, reservoirs and rivers were sampled at different periods of the hydrological cycle (N = 3203). The biovolume of GFBMs was affected positively by phosphorus and negatively by nitrogen and turbidity. IIH and TR showed negative effects on the biovolume-environment relationship. The meta-regressions showed different relationships between biovolume and nitrogen for groups III, VII and VIII, as well as negative relationships in temporal data, which indicates that hydrological events had an effect on them. The results indicated that local variables, such as hydrodynamic conditions, can affect the strength of the relationships between biovolume, nitrogen and phosphorus, which causes a negative effect on GFBMs.