ALBERT

Description: Habitat patterns of subtropical and tropical planktic foraminifers in the Caribbean Sea were obtained from plankton samples collected in spring 2009 and 2013. The spatial distribution in surface waters (3.5 m water depth) and depth habitat patterns (surface to 400 m) of 33 species were compared with prevailing water-mass conditions (temperature, salinity, and chlorophyll-a concentration) and planktic foraminiferal test assemblages in surface sediments. Distribution patterns indicate a significant relationship with seawater temperature and trophic conditions. A reduction in standing stocks was observed close to the Orinoco River plume and in the Gulf of Paria, associated with high turbidity and concomitant low surface-water salinity. In contrast, a transient mesoscale patch of high chlorophyll concentration in the eastern Caribbean Sea was associated with higher standing stocks in near surface waters, including high abundances of Globigerinita glutinata and Neogloboquadrina dutertrei. Globorotalia truncatulinoides mainly lives close to the seasonal pycnocline and can be linked to winter conditions indicated by lower sea-surface temperatures (SSTs) of ∼20°C. Globigerinoides sacculifer and Globoturborotalita rubescens were associated with oligotrophic conditions in the pelagic Caribbean Sea during early spring and showed a synodic lunar reproduction cycle. The live assemblages in the water column from 2009 and 2013 were similar to those reported in earlier studies from the 1960s and 1990s and to assemblages of tests in the surface sediments. Minor differences in faunal proportions were attributed to seasonal variability and environmental differences at the local scale. An exception was the low relative abundance of Globigerinoides ruber in the Caribbean Sea in 2009 compared to surface sediment samples and plankton net samples collected in the 1960s and 1990s. Decreasing abundance of Gs. ruber white in the Caribbean Sea may be associated with increasing SSTs over past decades and changes in nutrient flux and primary production.

Description: Benthic foraminiferal faunas from the shelf and upper continental slope of the Celtic Sea (NE Atlantic) show a rich variety of Trochamminidae species. We recognized 31 taxa, of which 18 could be determined to species level. These 18 species comprise about 9% of all species of the family Trochamminidae that are described from Recent sediments worldwide. For species determination and generic classification, we used existing taxonomic concepts and assessed their applicability. Besides the morphology of the test and internal structures, different apertural. features play a fundamental role in the systematic subdivision of the Trochamminidae. The position of the aperture controls the chamber arrangement and, therefore, the final shape of the test. However, we found no relationship between the apertural features and shape of the chambers as well as between apertural features and mode of life. Using apertural features for a sound taxonomic designation of our specimens proves difficult, because apertures are often obscured. Further, combined morphological and molecular-phylogenetic studies are required to constrain the taxonomic relevance of apertural characteristics.

Description: Alexander Volker Altenbach was born in 1953 in Frankfurt/Main, Germany. Alex attended school in Königstein/Taunus, where he passed his Abitur in 1974. He then studied Geology and Paleontology at Goethe University, Frankfurt. During an internship on an oil rig in Denmark, he first experienced a professional working environment and the adventures of hydrocarbon exploration in the North Sea. For his diploma thesis Alex worked on the stratigraphy and tectonics of the Sierra de Montgai, in the Pyrenees, Spain, under the supervision of Rolf Schroeder, Senckenberg Museum, Frankfurt/M. The subject comprised a genuine geological mapping exercise and biostratigraphic dating of the exposed formations. Stratigraphic ages were determined with the Mesozoic orbitoids and planktonic foraminifera in thin sections. Alex shared the long travels to Spain with his two companions Hans-Joachim Wallrabe-Adams (aka Kolli) and Peter Brinnel, enjoying an old “concha naranja” Volkswagen van, as well as field work in the spectacular scenery of the Sierra de Montsec, and living the Catalonian lifestyle. As late as 1993, the theme of Alex’s habilitation defense again was the geology of the Sierra de Montsec, for which he had kept his fascination (cf. Wallrabe-Adams et al., 2005). Being challenged by disentangling the complicated tectonic structure of the Sierra de Montgai, Alex learnt Fortran78 to produce a virtual Schmid net on the central university computer, visualizing different deformation styles of the different tectonic units. His early professional computer programming probably gave rise to his later endeavor in computing. Attracted by the developments in Marine Geosciences at Kiel University during the early 1980s, Alex joined the Micropaleontology Group of Gerhard Friedrich Lutze, and commenced …