Humic substances occur in all kinds of aquatic systems, but are particularly important in northern, coniferous areas. They strongly modify the aquatic ecosystems and also constitute a major problem in the drinking water supply. This volume covers all aspects of aquatic humic substances, from their origin and chemical properties, their effects on light and nutrient regimes and biogeochemical cycling, to their role regarding organisms, productivity and food web organization from bacteria to fish. Special emphasis is paid to carbon cycling and food web organization in humic lakes, but aspects of marine carbon cycling related to humus are treated as well.

Humic substances occur in all kinds of aquatic systems, but are particularly important in northern, coniferous areas. They strongly modify the aquatic ecosystems and also constitute a major problem in the drinking water supply. This volume covers all aspects of aquatic humic substances, from their origin and chemical properties, their effects on light and nutrient regimes and biogeochemical cycling, to their role regarding organisms, productivity and food web organization from bacteria to fish. Special emphasis is paid to carbon cycling and food web organization in humic lakes, but aspects of marine carbon cycling related to humus are treated as well.

This book is written as a reference on organic substances in natural waters and as a supplementary text for graduate students in water chemistry. The chapters address five topics: amount, origin, nature, geochemistry, and characterization of organic carbon. Of these topics, the main themes are the amount and nature of dissolved organic carbon in natural waters (mainly fresh water, although seawater is briefly discussed). It is hoped that the reader is familiar with organic chemistry, but it is not necessary. The first part of the book is a general overview of the amount and general nature of dissolved organic carbon. Over the past 10 years there has been an exponential increase in knowledge on organic substances in water, which is the result of money directed toward the research of organic compounds, of new methods of analysis (such as gas chromatography and mass spectrometry), and most importantly, the result of more people working in this field. Because of this exponential increase in knowledge, there is a need to pull together and summarize the data that has accumulated from many disciplines over the last decade.

Humic Substances color all waters more or less brown. Their concentrations exceed all carbon of living organisms by at least one order of magnitude. Opposite to former paradigms, they participate in almost any metabolic pathway. They protect against UV-irradation, enable indirect photolysis and, thus, purify hazardous chemicals, they provide inorganic and organic nutrients, may form cryptic genes with DNA and dampen metabolic fluctuations. More recently they can increase adverse effects of hazardous chemicals and they can directly interfere with organisms. The book tries to relate effects to structural features.

The first comprehensive account of these important environmental interactions, this book describes the binding reactions, how they can be mathematically modelled, and how this knowledge is used to interpret environmental phenomena in soils, waters and sediments. A valuable resource for advanced undergraduate and graduate students, environmental scientists, ecologists and geochemists.