| 1. |
- Algesten, Grete, et al.
(author)
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Organic carbon budget for the Gulf of Bothnia
- 2006
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In: Journal of Marine Systems. - : Elsevier BV. - 0924-7963 .- 1879-1573. ; 63:3-4, s. 155-161
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Journal article (peer-reviewed)abstract
- We calculated input of organic carbon to the unproductive, brackish water basin of the Gulf of Bothnia from rivers, point sources and the atmosphere. We also calculated the net exchange of organic carbon between the Gulf of Bothnia and the adjacent marine system, the Baltic Proper. We compared the input with sinks for organic carbon; permanent incorporation in sediments and mineralization and subsequent evasion of CO2 to the atmosphere. The major fluxes were riverine input (1500 Gg C year(-1)), exchange with the Baltic Proper (depending on which of several possible DOC concentration differences between the basins that was used in the calculation, the flux varied between an outflow of 466 and an input of 950 Gg C year(-1)), sediment burial (1100 Gg C year) and evasion to the atmosphere (3610 Gg C year(-1)). The largest single net flux was the emission of CO2 to the atmosphere, mainly caused by bacterial mineralization of organic carbon. Input and output did not match in our budget which we ascribe uncertainties in the calculation of the exchange of organic carbon between the Gulf of Bothnia and the Baltic Proper, and the fact that CO2 emission, which in our calculation represented 1 year (2002) may have been overestimated in comparison with long-term means. We conclude that net heterotrophy of the Gulf of Bothnia was due to input of organic carbon from both the catchment and from the Baltic Proper and that the future degree of net heterotrophy will be sensible to both catchment export of organic carbon and to the ongoing eutrophication of the Baltic Proper.
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| 2. |
- Humborg, Christoph, et al.
(author)
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Dissolved silicate dynamics in boreal and subarctic rivers - vegetation control over temperature?
- 2005. - 1
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In: The Silicon Cycle: Human Perturbations and Impacts on aquatic systems. - Washington, DC : Island Press. ; , s. 53-69
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Book chapter (other academic/artistic)abstract
- Silicon is among the most abundant elements on earth. It plays a key but largely unappreciated role in many biogeochemical processes, including those that regulate climate and undergird marine food webs. The Silicon Cycle is the first book in more than 20 years to present a comprehensive overview of the silicon cycle and issues associated with it. The book summarizes the major outcomes of the project Land-Ocean Interactions: Silica Cycle, initiated by the Scientific Community on Problems of the Environment (SCOPE) of the International Council of Scientific Unions (ICSU). It tracks the pathway of silicon from land to sea and discusses its biotic and abiotic modifications in transit as well as its cycling in the coastal seas. Natural geological processes in combination with atmospheric and hydrological processes are discussed, as well as human perturbations of the natural controls of the silicon cycle.
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| 3. |
- Pacini, N, et al.
(author)
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Nutrient Processes and Consequences.
- 2008
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In: Ecohydrology; Processes, Models and Case Studies. - Oxford : Oxford University Press. - 9781845930028 ; , s. -391
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Book chapter (other academic/artistic)abstract
- This book contains 15 chapters dealing with the integration of ecology with hydrology at the river basin scale. The patterns and processes in the catchment including nutrients, lotic vegetation and aquatic faunal processes are covered. In addition, the benefits and risks of ecological modelling to water management and nutrient budget modelling for lakes and watershed restoration are discussed. The roles of ecohydrology in managing the savannah ecosystem, agricultural landscape, and watershed development are explored.
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| 4. |
- Rahm, Lars, 1948-, et al.
(author)
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Dissolved silicate dynamics in boreal and subarctic rivers - vegetation control over temperature?
- 2006. - 1
-
In: The Silicon Cycle. - New York : Island Press. ; , s. 53-69
-
Book chapter (peer-reviewed)abstract
- Silicon is among the most abundant elements on earth. It plays a key but largely unappreciated role in many biogeochemical processes, including those that regulate climate and undergird marine food webs. The Silicon Cycle is the first book in more than 20 years to present a comprehensive overview of the silicon cycle and issues associated with it. The book summarizes the major outcomes of the project Land-Ocean Interactions: Silica Cycle, initiated by the Scientific Community on Problems of the Environment (SCOPE) of the International Council of Scientific Unions (ICSU). It tracks the pathway of silicon from land to sea and discusses its biotic and abiotic modifications in transit as well as its cycling in the coastal seas. Natural geological processes in combination with atmospheric and hydrological processes are discussed, as well as human perturbations of the natural controls of the silicon cycle.
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| 5. |
- Sahlberg, Jörgen, et al.
(author)
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Light limitation of primary production in high latitude reservoirs
- 2005
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In: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 9:6, s. 707-720
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Journal article (peer-reviewed)abstract
- To explore the effects of vertical mixing on the primary production in a northern reservoir, a Lagrangian particle dispersion model was coupled to a 1-D reservoir model where the vertical mixing was calculated using a k - ε model together with an empirically-based deep-water eddy viscosity. The primary production of each phytoplankton cell is assumed to be a function of the ambient light and not to be nutrient limited. The photoadaption follows first-order kinetics where the photoadaptive variables, α, β, and Pm, describe the coefficients of the photosynthesis-irradiance curve. The model is applied to the northern reservoir Akkajaure, which is strongly regulated with a mean and maximum depth of 30 m and 100 m respectively. Based on the release of 1000 particles (plankton), the model calculated the mean primary production of each plankton, during four different growing seasons. Vertical mixing has a substantial effect on the vertical distribution of phytoplankton and, thus, on the primary production in a reservoir. It was found that primary production was greater in a cold summer with weak stratification than in a warm summer when the reservoir was more stratified. © EGU.
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