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- Bergström, Ann-Kristin, et al.
(författare)
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Bacterioplankton production in humic Lake Örträsket in relation to input of bacterial cells and input of allochthonous organic carbon
- 2000
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Ingår i: Microbial Ecology. - : Springer. - 0095-3628 .- 1432-184X. ; 39:2, s. 101-115
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Tidskriftsartikel (refereegranskat)abstract
- In order to compare riverine bacteria input with lake water bacterial production and grazing loss with output loss, a bacterial cell budget was constructed for humic Lake Ortrasket in northern Sweden. The riverine input of bacterial cells in 1997 represented 29% of the number of bacterial cells produced within the layer of the lake affected by inlet water. A large share of the in situ lake bacterial production was consumed by grazers, mainly flagellates, which stresses the importance of bacteria as energy mobilizers for the pelagic food web in the lake. The bacterial production in Lake Ortrasket, which is almost entirely dependent on humic material as an energy source, was clearly stimulated by high flow episodes which brought high amounts of little degraded material into the lake. During base flow condition the bacterial production in the inlet rivers was high, which led to an input of more degraded material to the lake. This material did not stimulate the lake bacterial production. Internal factors that determined the utilization of the allochthonous DOC in the lake were the retention time and the exposure to light and high temperatures. Thus, the potential for in situ production of bacteria in Lake Ortrasket was to a large extent a function of how precipitation and runoff conditions affected terrestrial losses and river transport of humic material.
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| 2. |
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| 3. |
- Jansson, Mats, et al.
(författare)
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Allochthonous organic carbon and phytoplankton/bacterioplankton production relationships in lakes
- 2000
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Ingår i: Ecology. - 0012-9658 .- 1939-9170. ; 81:11, s. 3250-3255
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Tidskriftsartikel (refereegranskat)abstract
- Humic lakes with high inputs of allochthonous dissolved organic carbon have a pelagic food chain that, to a large extent, is based on bacterioplankton energy mobilization from allochthonous organic carbon compounds. This is in contrast to clear lakes in which total pelagic production is based mainly on phytoplankton photosynthesis. The energy economy in humic lakes may be less efficient than in clear lakes, because it is Likely that one more link is included in the food chain. Lake data from Scandinavia and North America demonstrate that shifts between food chains based on heterotrophic production and food chains based on primary production can take place at moderate increases or decreases in the concentration of dissolved organic carbon from allochthonous sources. Large variations in the loading of allochthonous organic carbon (e.g., due to climatic variations) may have considerable effects on the biostructure and productivity of lakes.
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