dissolved humic substances

Humic substances also have the potential to suppress fungal growth, as shown with the water mould Saprolegnia parasitica, and force the fungus to respond by spore production.

here we present evidence that dissolved HS are indeed taken up and interact directly and/or indirectly with freshwater organisms

There is accumulating evidence that the quality of the HS controls microbial growth. In total, net-heterotrophy may result from HS-mediated suppression of primary production by the quinone structures and/or from HS-mediated support of microbial growth. As there is also evidence that HS have the potential to support photoautotrophic growth and suppress microbial growth, the opposite community effect could result.

they can modulate the numbers of offspring in a nematode and feminise fish and amphibians... HS also have the potential to act as chemical attractants

HS modulate the multixenobiotic resistance activity and probably other membrane-bound pumps. This property may lead to the increased bioaccumulation of xenobiotic chemicals.

HS also have the potential to suppress fungal growth, as shown with the water mould Saprolegnia parasitica and force the fungus to respond by spore production.

here we present evidence that dissolved HS are indeed taken up and interact directly and/or indirectly with freshwater organisms

By applying a quantitative structure activity relationship approach, we show that quinones in the HS interfere with photosynthetic electron transport.

By applying a quantitative structure activity relationship approach, we show that quinones in the HS interfere with photosynthetic electron transport.

There is accumulating evidence that the quality of the HS controls microbial growth. In total, net-heterotrophy may result from HS-mediated suppression of primary production by the quinone structures and/or from HS-mediated support of microbial growth. Since there is also evidence that HS have the potential to support photoautotrophic growth and suppress microbial growth, the opposite community effect could result.

In some macrophytes and algae we show that HS interfere with photosynthesis and growth. For instance, the presence of HS suppresses cyanobacteria more than eukaryotic algae.

In some macrophytes and algae we show that HS interfere with photosynthesis and growth. For instance, the presence of HS suppresses cyanobacteria more than eukaryotic algae.

dissolved HS exert a mild chemical stress upon aquatic organisms in many ways; they induce molecular chaperones (stress shock proteins), induce and modulate biotransformation enzymes... Furthermore, they produce an oxidative stress... HS modulate the multixenobiotic resistance activity and probably other membrane-bound pumps

In very soft, humic freshwaters, such as the Rio Negro, Brazil, HS stimulate the uptake of essential ions, such as Na and Ca, at extremely low pH (3.5–4.0) and prevent the ionoregulatory disturbance induced by acid waters, thereby enabling fish to survive in these environments.

In very soft, humic freshwaters, such as the Rio Negro, Brazil, HS stimulate the uptake of essential ions, such as Na and Ca, at extremely low pH (3.5–4.0) and prevent the ionoregulatory disturbance induced by acid waters

dissolved HS exert a mild chemical stress upon aquatic organisms in many ways; they induce molecular chaperones (stress shock proteins), induce and modulate biotransformation enzymes... Furthermore, they produce an oxidative stress, which may lead to membrane oxidation

Humic substances modulate the multixenobiotic resistance activity and, probably, other membrane-bound pumps. This property may lead to the increased bioaccumulation of xenobiotic chemicals.