Contiunous surface water uncorrected and quench-corrected active fluorescence and derived chlorophyll a concentration using calibration by HPLC pigments during POLARSTERN cruise ANT-XXV/1

The relationship between phytoplankton assemblages and the associated optical properties of the water body is important for the further development of algorithms for large-scale remote sensing of phytoplankton biomass and the identification of phytoplankton functional types (PFTs), which are often representative for different biogeochemical export scenarios. Optical in-situ measurements aid in the identification of phytoplankton groups with differing pigment compositions and are widely used to validate remote sensing data. In this study we present results from an interdisciplinary cruise aboard the RV Polarstern along a north-to-south transect in the eastern Atlantic Ocean in November 2008. Phytoplankton community composition was identified using a broad set of in-situ measurements. Water samples from the surface and the depth of maximum chlorophyll concentration were analyzed by high performance liquid chromatography (HPLC), flow cytometry, spectrophotometry and microscopy. Simultaneously, the above- and underwater light field was measured by a set of high spectral resolution (hyperspectral) radiometers. An unsupervised cluster algorithm applied to the measured parameters allowed us to define bio-optical provinces, which we compared to ecological provinces proposed elsewhere in the literature. As could be expected, picophytoplankton was responsible for most of the variability of PFTs in the eastern Atlantic Ocean. Our bio-optical clusters agreed well with established provinces and thus can be used to classify areas of similar biogeography. This method has the potential to become an automated approach where satellite data could be used to identify shifting boundaries of established ecological provinces or to track exceptions from the rule to improve our understanding of the biogeochemical cycles in the ocean.

Phycoerythrin concentration during POLARSTERN cruises ANT-XXIV/4, ANT-XXV/1, and ANT-XXVI/4

Phycobiliproteins are a family of water-soluble pigment proteins that play an important role as accessory or antenna pigments and absorb in the green part of the light spectrum poorly used by chlorophyll a. The phycoerythrins (PEs) are one of four types of phycobiliproteins that are generally distinguished based on their absorption properties. As PEs are water soluble, they are generally not captured with conventional pigment analysis. Here we present a statistical model based on in situ measurements of three transatlantic cruises which allows us to derive relative PE concentration from standardized hyperspectral underwater radiance measurements (Lu). The model relies on Empirical Orthogonal Function (EOF) analysis of Lu spectra and, subsequently, a Generalized Linear Model with measured PE concentrations as the response variable and EOF loadings as predictor variables. The method is used to predict relative PE concentrations throughout the water column and to calculate integrated PE estimates based on those profiles.

(Table 1) Magnetozone boundaries at DSDP Site 68-503

The paleomagnetic measurement procedure at Site 503 was similar to that described for Site 502 (See preceding chapter). Each core section was measured with the longcore spinner magnetometer at 10-cm intervals. In addition, one or more discrete samples were taken from each core section for measurement of the total magnetic vector and its stability against progressive AF demagnetization. There were noteworthy differences in conditions at Site 503, however, that affected the quality and interpretation of the magnetic data and require comment. The most serious problem we encountered was the presence of rust scale from the drill string. Although the dark flecks typically were concentrated near the top of every recovered sediment core, they also smeared down a meter or more between the core liner and sediment, even when the sediment showed no indication of drilling disturbance. Individual rust scales proved to be highly magnetic - presumably because they incorporate small pieces of unoxidized metal. The anomalously high remanent intensities, several orders of magnitude above the uncontaminated sediment values, and scattered remanent directions observed in long-core magnetic measurements on many cores from Site 503 could be attributed to the presence of rust scale.

Morphological descriptions from the recent bivalve of the genus Calyptogena (Vesicomyidae)

The genus Calyptogena (Bivalvia: Vesicomyidae) comprises highly specialized bivalves living in symbiosis with sulphur-oxidizing bacteria in reducing habitats. In this study, the genus is revised using shell and anatomical features. The work is based on type material, as well as on the extensive collection of vesicomyids obtained during twelve expeditions to the Pacific and Indian Oceans. Nine Recent species are ascribed to the genus Calyptogena, four of which are new: C. pacifica Dall, 1891, C. fausta Okutani, Fujikura & Hashimoto, 1993, C. rectimargo Scarlato, 1981, C. valdiviae (Thiele & Jaeckel, 1931), C. gallardoi Sellanes & Krylova, 2005, C. goffrediae n. sp., C. starobogatovi n. sp., C. makranensis n. sp. and C. costaricana n. sp. The characteristic features of Calyptogena are: shell up to 90 mm in length, elongate-elliptical or elongate; presence of escutcheon; presence of broad posterior ramus (3b) of right subumbonal cardinal tooth as well as right posterior nymphal ridge; absence of pallial sinus as a result of attachment of intersiphonal septal retractor immediately adjacent to ventral surface of posterior adductor; absence of processes on inner vulva of inhalant siphon; presence of inner demibranch only, with descending and ascending lamellae with interlamellar septa not divided into separate tubes. The most closely related taxa to Calyptogena are probably the genus Isorropodon Sturany, 1896, and the group of species represented by 'Calyptogena' phaseoliformis Métivier, Okutani & Ohta, 1986. These groups have several characters in common, namely absence of pallial sinus, presence of single inner pair of demibranchs and absence of processes on inner vulva of inhalant siphon. The worldwide distribution of the genus Calyptogena suggests that methane seeps at continental margins are the major dispersal routes and that speciation was promoted by geographical isolation. Recent species diversity and fossil records indicate that the genus originated in the Pacific Ocean. Sufficient data to discuss the distribution at species level exist only for C. pacifica, which has a remarkably narrow bathymetric range. Published studies on the physiology of C. pacifica suggest that adaptation to a specific geochemical environment has led to coexisting vesicomyid genera. The bacteria-containing gill of C. pacifica and other Calyptogena species is one of the most specialized in the family Vesicomyidae and may reflect these ecological adaptations.