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Living benthic foraminiferal assemblages were monitored between January and July 2004 in the Kiel Bight, Baltic Sea. Phytoplankton blooms and the deposition of organic detritus were depicted by fluorometer hydro casts and pigment concentrations in surface sediments. Three depositional pulses of organic matter were identified by high phytoplankton concentrations above the sea floor and elevated pigment concentrations in the surface sediment. The foraminiferal assemblage composition remained rather constant but the population density of Elphidium excavatum clavatum showed a two- to six-fold increase within a few days after organic detritus deposition. The foraminiferal assemblage composition was compared to earlier studies in this area. Elphidium excavatum, Ammotium cassis and E. incertum dominated the living fauna in the 1960s and 1970s. The recent survey revealed a predominance of E. excavatum subspecies (more than 90% of the living assemblage). The average population densities were six times higher than in the 1970s. Data structure and model calculations suggested that E. excavatum clavatum is able to reproduce rapidly, with high offspring numbers at elevated food supply. The diminution of A. cassis has occurred in Kiel Bight during the last ten years and was most likely induced by a period of low deep-water salinities in the early 1990s.

(IF 1.30; Q2); International audience; The present paper deals with the systematic description of the belemnite assemblages from the Lower Jurassic, collected at the Roche Blain quarry, Fresney-le-Puceux. In spite of the reduced thickness of the succession at Fresney-le-Puceux, 13 successive ammonite chronozones could be documented in this rather unique outcrop situation in mainland Europe. Twelve genera and 26 species of belemnites belonging to the Passaloteuthididae, Hastitidae, Megateuthididae, Salpingoteuthididae, and family incertae sedis are described and illustrated herein. The stratigraphical range of the belemnites is correlated with the standard ammonite zonation, using the chronozone concept: the described specimens range from the lower Pliensbachian (Davoei Chronozone) to the uppermost Toarcian (Aalensis Chronozone) while ammonites indicate the Aalenian (Murchisonae Chronozone) to be present too, but these beds delivered no identifiable belemnites so far. The belemnite diversity from Normandy is compared to data from coeval outcrops in Western and Central Europe.; Cet article traite de la systématique des bélemnites du Jurassique inférieur récoltées dans la carrière de la Roche Blain à Fresney-le-Puceux. Malgré l’épaisseur réduite de la succession de Fresney-le-Puceux, 13 chronozones successives d’ammonites ont été documentées dans cet affleurement assez unique en Europe continentale. Douze genres et 26 espèces de bélemnites appartenant aux Passaloteuthididae, aux Hastitidae, aux Megateuthididae et aux Salpingoteuthididae, ainsi qu’à une famille incertae sedis, sont décrits et illustrés ici. L’extension stratigraphique des bélemnites est corrélée avec la zonation standard des ammonites en utilisant le concept de chronozone : les spécimens décrits s’étendent du Pliensbachien (Chronozone à Davoei) au Toarcien supérieur (Chronozone à Aalensis), tandis que les ammonites indiquent que l’Aalénien (Chronozone à Murchisonae) pourrait être présent, mais ces niveaux n’ont pas livré de bélemnites identifiables jusqu’ici. La diversité des bélemnites de Normandie est comparée à celle d’affleurements équivalents en Europe occidentale et centrale.