The early summer bloom of dinoflagellates in the North Sea, with special reference to 1971

1977 ◽  
Vol 40 (4) ◽  
pp. 327-336 ◽  
Author(s):  
J. D. Dodge
Keyword(s):  
Special Reference ◽  
North Sea ◽  
Early Summer ◽  
The North ◽  
The North Sea ◽  
Summer Bloom

On the Marina Cladocera from the Northumbrian Plankton

1933 ◽  
Vol 19 (1) ◽  
pp. 177-226 ◽  
Author(s):  
Olag M. Jorgensen
Keyword(s):  
North Sea ◽  
Body Shape ◽  
Early Summer ◽  
Brood Chamber ◽  
The North ◽  
Points Of Interest ◽  
The North Sea ◽  
Inshore Waters ◽  
The Baltic

From an analysis of previous records of E. nordmanni, considered in conjunction with those furnished by the present investigation, the following points of interest emerge.1. E. nordmanni, while being generally distributed in the North Sea and adjacent waters throughout the summer months, has been shown to breed freely in inshore waters in early summer and again in autumn when maximum numbers of individuals are obtained.2. These two periods of maximal abundance are produced as the result of successive parthenogenetic broods and alternate with periods of depression. This is indicated not only by the sexually-produced winter-egg, but also by a reduction in the number of embryos contained in the brood chamber and consequent change in body-shape. This serves to show that the supposedly distinct races, described as being characteristic of the North Sea and the Baltic, have no doubt been founded on material taken at different periods of the agamic phase.

scholarly journals Prey selection by North Sea herring (Clupea harengus), with special reference to fish eggs

2006 ◽  
Vol 64 (1) ◽  
pp. 60-68 ◽  
Author(s):  
F. H. I. D. Segers ◽  
M. Dickey-Collas ◽  
A. D. Rijnsdorp
Keyword(s):  
Special Reference ◽  
North Sea ◽  
Prey Selection ◽  
Ecological Impact ◽  
Clupea Harengus ◽  
Trophic Levels ◽  
Trawl Survey ◽  
Fish Eggs ◽  
The North ◽  
The North Sea

Abstract Segers, F. H. I. D, Dickey-Collas, M., and Rijnsdorp, A. D. 2007. Prey selection by North Sea herring (Clupea harengus), with special reference to fish eggs. ICES Journal of Marine Science, 64: 60–68. he herring stock in the North Sea in recent years has recovered to a relatively high biomass, and here we investigate prey selection of individual North Sea herring when population numbers are high. The diet composition, and specifically pelagic fish eggs, was investigated in February 2004. Samples of herring from the International Bottom Trawl Survey were used for stomach analysis, and ichthyoplankton samples from the southern North Sea were used to investigate selection. Crustaceans were the main diet component. The average diameter of the fish eggs recovered from the stomachs was significantly larger than that of the eggs collected in the field. In addition, the frequency at which the latest developmental stages occurred in the herring stomachs was significantly different from the frequency at which these stages were found in the field. This shows selective foraging. There was a relationship between the amount of food and the number of eggs in a herring stomach: the fullest stomachs tended to contain fewer fish eggs. This suggests that herring forage on eggs when other prey are not available. Hence, it is likely that the dynamics of multiple trophic levels influence the ecological impact of a large herring stock on the North Sea ecosystem.

scholarly journals Virus-like particles in a summer bloom of Emiliania huxleyi in the North Sea

1996 ◽  
Vol 10 ◽  
pp. 105-113 ◽  
Author(s):  
CPD Brussaard ◽  
RS Kempers ◽  
AJ Kop ◽  
R Riegman ◽  
M Heldal
Keyword(s):  
North Sea ◽  
Emiliania Huxleyi ◽  
Virus Like Particles ◽  
The North ◽  
The North Sea ◽  
Summer Bloom

scholarly journals Investigation on the trophic state of the North Sea for three years (1994–1996) simulated with the ecosystem model ERSEM – the role of a sharp NAOI decline

2004 ◽  
Vol 1 (1) ◽  
pp. 725-754 ◽  
Author(s):  
H. J. Lenhart ◽  
J. Pätsch ◽  
W. Kühn ◽  
A. Moll ◽  
T. Pohlmann
Keyword(s):  
North Sea ◽  
Net Primary Production ◽  
Ecosystem Model ◽  
Early Summer ◽  
The North ◽  
The North Sea ◽  
Strong Transition ◽  
Northern North Sea ◽  
Sea Area

Abstract. Applying the ecosystem model ERSEM to the Northwest-European shelf (48°–63°N, 15°W–12°E) the years 1994-1996 were simulated, which exhibit an extremely strong transition in North Atlantic Oscillation index (NAOI): from a high-NAOI to a low-NAOI regime. In order to be far enough from the boundaries of the model area the results and budgets are focussed on the North Sea area. For this region the model was validated against climatological values of nitrate as representative nutrient. For all three years the North Sea was found to be net heterotrophic: organic material was imported, inorganic material was exported. The strength of this "remineralisation-machine" was large during NAOI-high years (1994 and 1995). It was weaker in 1996 with a low NAOI. This was caused by higher net primary production in the northern North Sea during summer 1996. In this year the stratification was weaker and began later allowing the deep nutrient-rich water in the northern North Sea to be mixed into the upper layers also during early summer.

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