| 1. |
- McCrackin, Michelle L., et al.
(författare)
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Opportunities to reduce nutrient inputs to the Baltic Sea by improving manure use efficiency in agriculture
- 2018
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Ingår i: Regional Environmental Change. - : Springer Science and Business Media LLC. - 1436-3798 .- 1436-378X. ; 18:6, s. 1843-1854
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Tidskriftsartikel (refereegranskat)abstract
- While progress has been made in reducing external nutrient inputs to the Baltic Sea, further actions are needed to meet the goals of the Baltic Sea Action Plan (BSAP), especially for the Baltic Proper, Gulf of Finland, and Gulf of Riga sub-basins. We used the net anthropogenic nitrogen and phosphorus inputs (NANI and NAPI, respectively) nutrient accounting approach to construct three scenarios of reduced NANI-NAPI. Reductions assumed that manure nutrients were redistributed from areas with intense animal production to areas that focus on crop production and would otherwise import synthetic and mineral fertilizers. We also used the Simple as Necessary Baltic Long Term Large Scale (SANBALTS) model to compare eutrophication conditions for the scenarios to current and BSAP-target conditions. The scenarios suggest that reducing NANI-NAPI by redistributing manure nutrients, together with improving agronomic practices, could meet 54–82% of the N reductions targets (28–43 kt N reduction) and 38–64% P reduction targets (4–6.6 kt P reduction), depending on scenario. SANBALTS output showed that even partial fulfillment of nutrient reduction targets could have ameliorating effects on eutrophication conditions. Meeting BSAP targets will require addressing additional sources, such as sewage. A common approach to apportioning sources to external nutrients loads could enable further assessment of the feasibility of eutrophication management targets.
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| 2. |
- Gustafsson, Erik, et al.
(författare)
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Key processes in the coupled carbon, nitrogen, and phosphorus cycling of the Baltic Sea
- 2017
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Ingår i: Biogeochemistry. - : Springer Science and Business Media LLC. - 0168-2563 .- 1573-515X. ; 134:3, s. 301-317
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Tidskriftsartikel (refereegranskat)abstract
- In this study we examine pools of carbon (C), nitrogen (N), and phosphorus (P) in the Baltic Sea, both simulated and reconstructed from observations. We further quantify key fluxes in the C, N, and P cycling. Our calculations include pelagic reservoirs as well as the storage in the active sediment layer, which allows a complete coverage of the overall C, N, and P cycling on a system-scale. A striking property of C versus N and P cycling is that while the external supplies of total N and P (TN and TP) are largely balanced by internal removal processes, the total carbon (TC) supply is mainly compensated by a net export out of the system. In other words, external inputs of TN and TP are, in contrast to TC, rather efficiently filtered within the Baltic Sea. Further, there is a net export of TN and TP out of the system, but a net import of dissolved inorganic N and P (DIN and DIP). There is on the contrary a net export of both the organic and inorganic fractions of TC. While the pelagic pools of TC and TP are dominated by inorganic compounds, TN largely consists of organic N because allochthonous organic N is poorly degradable. There are however large basin-wise differences in C, N, and P elemental ratios as well as in inorganic versus organic fractions. These differences reflect both the differing ratios in external loads and differing oxygen conditions determining the redox-dependent fluxes of DIN and DIP.
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| 3. |
- Savchuck, Oleg P., 1948-
(författare)
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Large-Scale Nutrient Dynamics in the Baltic Sea, 1970–2016
- 2018
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The Baltic Sea is one of the world's marine areas well-covered by both long-term observations and oceanographic studies. It is also a large coastal area in which eutrophication had already been recognized half a century ago. While the mechanisms of eutrophication are largely understood, several features are less recognized and sometimes neglected, including: (a) natural and anthropogenic North-South and East-West nutrient gradients within the drainage basin and marine ecosystems; (b) the compensatory potential of the interconnectivity between the Baltic Sea basins; (c) long nutrient residence times and high buffer capacity of the system, resulting in slow responses to nutrient load reductions. Particularly important is the interaction of (d) naturally occurring saltwater inflows sporadically ventilating deep water layers and (e) a partly man-made intensification of biological oxygen consumption. Resulting redox alterations of biogeochemical nitrogen and phosphorus cycles are locked in a “vicious circle” that promotes cyanobacterial nitrogen fixation, thereby hindering nitrogen load reduction and sustaining an elevated trophic state. This tight coupling of natural environmental variation and human impacts complicates both scientific studies and management recommendations. Our primary objective is to describe all these features and mechanisms with the best available data on nutrient loads, and unique estimates of the basin-wide nutrient pools. These data are presented as both long-term time series and empirical nutrient budgets. The analysis is supplemented by results of biogeochemical modeling. A second, more practical objective is to make these time series available to the community.
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| 4. |
- Savchuck, Oleg P., 1948-
(författare)
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Myths of the Baltic Sea eutrophication
- 2018
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Ingår i: Journal of Aquaculture & Marine Biology. - : MedCrave Group, LLC. - 2378-3184. ; 7:2, s. 92-93
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Vladimirova, Oksana M., et al.
(författare)
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Modelling dissolved organic nutrients in the Gulf of Finland
- 2018
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Ingår i: Fundamental and Applied Hydrophysics. - 2073-6673. ; 11:4, s. 90-101
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Tidskriftsartikel (refereegranskat)abstract
- St.-Petersburg model of eutrophication (SPBEM) has been modified for improving description of organic matter as apart of the nutrient biogeochemical cycles. The dynamics of labile and refractory fractions of dissolved organic nitrogenand phosphorus are now described with four additional equations. The modification was tested at the Gulf of Finland in anumerical experiment made with plausible initial and actual boundary conditions for the years 2009—2014. Comparisonof simulation with the available field observations indicates quite reasonable reproducibility of seasonal and inter-annualvariations of spatial distribution of hydrophysical and biogeochemical characteristics, including almost a perfect matchbetween simulated and observed dynamic of organic nutrients. The most important distinction from natural prototypesis the overestimated total amounts of inorganic nitrogen and phosphorus, which can be caused by the deficiencies inthe prescription of initial and boundary conditions as well as in the current parameterizations of pathways and rates ofmineralization fluxes. The finer tuning of SPBEM-2 requires more extensive sensitivity analysis.
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