Observations of near-bottom currents in Bornholm Basin, Slupsk Furrow and Gdansk Deep

On Dense Bottom Currents in the Baltic Deep Water

Hydrology Research ◽

10.2166/nh.1977.0024 ◽

1977 ◽

Vol 8 (5) ◽

pp. 297-316 ◽

Cited By ~ 17

Author(s):

Flemming Bo Pedersen

Keyword(s):

Deep Water ◽

Oxygen Supply ◽

Bottom Current ◽

Bornholm Basin ◽

Bottom Currents ◽

Water Currents ◽

Baltic Proper ◽

The Baltic

A rational entrainment function for a subcritical dense bottom current is outlined. As an example the formula has been used to some orders of magnitude calculations of the deep water currents from the Darss Sill to the Stolpe Channel. It is shown that the salt and oxygen supply to the deep water of the Baltic Proper during a »normal« year stems from this bottom current and its entrained water. The renewal of the deep water in the Baltic Proper can be traced in the Bornholm Basin, and hence it is strongly recommended, that continous measurements of salinity, temperature, oxygen, phosphate etc. are performed in the Bornholm Basin, especially in the highly entraining area just north of Bornholm.

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Survival and dispersal variability of pelagic eggs and yolk-sac larvae of central and eastern baltic flounder (Platichthys flesus): application of biophysical models

ICES Journal of Marine Science ◽

10.1093/icesjms/fsw163 ◽

2016 ◽

Vol 74 (1) ◽

pp. 41-55 ◽

Cited By ~ 7

Author(s):

Hans-Harald Hinrichsen ◽

Christoph Petereit ◽

Anders Nissling ◽

Isa Wallin ◽

Didzis Ustups ◽

...

Keyword(s):

Survival Rates ◽

Relative Survival ◽

Larval Survival ◽

Yolk Sac ◽

Bornholm Basin ◽

Gotland Basin ◽

Gdansk Deep ◽

Spawning Areas ◽

Pelagic Eggs ◽

Arkona Basin

A hydrodynamic model coupled with a Lagrangian particle tracking technique was utilized to simulate spatially and temporally resolved long-term environmentally related (i) size of habitat suitable for reproduction, (ii) egg/yolk-sac larval survival, (iii) separation of causes of mortality, and (iv) connectivity between spawning areas of Baltic flounder with pelagic eggs. Information on reproduction habitat requirements and mortality sources were obtained from field or laboratory studies. In our modelling study we only quantified physical processes generating heterogeneity in spatial distribution of eggs and yolk-sac larvae, as e.g. predation is not accounted for. The spatial extent of eggs and larvae represented as modelled particles is primarily determined by oxygen and salinity conditions. The reproduction habitat most suitable was determined for the Gdansk Deep, followed by the Bornholm Basin. Relatively low habitat suitability was obtained for the Arkona Basin and the Gotland Basin. The model runs also showed yolk-sac larval survival to be to a large extent affected by sedimentation. Eggs initially released in the Arkona Basin and Bornholm Basin are strongly affected by sedimentation compared with those released in the Gdansk Deep and Gotland Basin. Highest relative survival of eggs occurred in the Gdansk Deep and in the Bornholm Basin. Relatively low survival rates in the Gotland Basin were attributable to oxygen-dependent mortality. Oxygen content had almost no impact on survival in the Arkona Basin. For all spawning areas mortality caused by lethally low temperatures was only evident after severe winters. Buoyancy of eggs and yolk-sac larvae in relation to topographic features appear as a barrier for the transport of eggs and yolk-sac larvae and potentially limits the connectivity of early life stages between the different spawning areas.

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