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- Arneborg, Lars, 1969, et al.
(författare)
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MIXING IN FJORDS AND THE RELATION BETWEEN LOCAL ENERGY DISSIPATION AT A FJORD SILL AND RADIATED INTERNAL TIDES
- 2012
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Ingår i: TOS/ASLO/AGU 2012 Ocean Science Meeting abstract book, Salt Lake City, USA.
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Konferensbidrag (refereegranskat)abstract
- Diapycnal mixing in a sill fjord is vital for renewal of the deep water inside the sill. Tides can cause such mixing, both by local turbulence at the sill associated with supercritical baroclinic flow and internal hydraulic jumps, and by radiation of internal tides away from the sill that dissipate elsewhere and cause turbulence and mixing there. Previous studies tend to look at these two processes as independent of each others, whereas they in reality are closely linked: The internal tide generation depends on the hydraulic conditions at the fjord sill, and the internal hydraulic jump strength depends on the upstream and downstream radiated columnar disturbances which over time constitute the internal tides. An effort is done to link the hydraulic theory and the internal tide generation theory, and the result is compared to recent intensive observations over the Oslo fjord sill, including high-resolution microstructure profiler transects and mooring data on and inside the sill.
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| 2. |
- Berezina, Anfisa, et al.
(författare)
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Modelling the Influence from Biota and Organic Matter on the Transport Dynamics of Microplastics in the Water Column and Bottom Sediments in the Oslo Fjord
- 2021
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 13:19
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Tidskriftsartikel (refereegranskat)abstract
- The fate of microplastics (MP) in seawater is heavily influenced by the biota: the density of MP particles can be changed due to biofouling, which affects sinking, or MP can be digested by zooplankton and transferred into fecal pellets with increased sinking rate. We hypothesize that seasonal production and degradation of organic matter, and corresponding changes in the plankton ecosystem affect the MP capacity for transportation and burying in sediments in different seasons. This is simulated with a coupled hydrodynamical-biogeochemical model that provides a baseline scenario of the seasonal changes in the planktonic ecosystem and changes in the availability of particulate and dissolved organic matter. In this work, we use a biogeochemical model OxyDep that simulates seasonal changes of phytoplankton (PHY), zooplankton (HET), dissolved organic matter (DOM) and detritus (POM). A specifically designed MP module considers MP particles as free particles (MPfree), particles with biofouling (MPbiof), particles consumed by zooplankton (MPhet) and particles in detritus, including fecal pellets (MPdet). A 2D coupled benthic-pelagic vertical transport model 2DBP was applied to study the effect of seasonality on lateral transport of MP and its burying in the sediments. OxyDep and MP modules were coupled with 2DBP using Framework for Aquatic Biogeochemical Modelling (FABM). A depletion of MP from the surface water and acceleration of MP burying in summer period compared to the winter was simulated numerically. The calculations confirm the observations that the “biological pump” can be one of the important drivers controlling the quantity and the distribution of MP in the water column.
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