Terrestrial organic matter input suppresses biomass production in lake ecosystems

Preferential sequestration of terrestrial organic matter in boreal lake sediments

The molecular composition and origin has recently been demonstrated to play a critical role in the persistence of organic matter in lake water, but it is unclear to what degree chemical attributes and sources may also control settling and burial of organic matter in lake sediments. Here we compared the annual contribution of allochthonous and autochthonous sources to the organic matter settling...

Biomass turnover time in terrestrial ecosystems halved by land use

Relationship of trophic and chemical conditions to photobleaching of dissolved organic matter in lake ecosystems

Dissolved organic matter (DOM) is a major light-absorbing substance, responsible for much of the color in water bodies. When sunlight energy is absorbed by DOM, some color can be lost by the process of photobleaching. We measured rates of DOM photobleaching in thirty lakes that varied greatly in color, trophic status and ionic composition. Loss of color (measured as absorbance at 440 nm and exp...

Forests fuel fish growth in freshwater deltas

Aquatic ecosystems are fuelled by biogeochemical inputs from surrounding lands and within-lake primary production. Disturbances that change these inputs may affect how aquatic ecosystems function and deliver services vital to humans. Here we test, using a forest cover gradient across eight separate catchments, whether disturbances that remove terrestrial biomass lower organic matter inputs into...

Breaks in the cycle: dissolved organic nitrogen in terrestrial ecosystems

Dissolved organic nitrogen (DON) is present in soils and streams around the world. We are only now beginning to explore the important roles this chemically heterogeneous mixture of compounds plays in terrestrial nitrogen (N) cycling. Over centuries, DON leaching may represent a significant "leak" of N, which occurs because plants and microbes cannot prevent DON losses, even in times of high N d...