ALBERT

Description: We investigated the gelatinous carnivore zooplankton community in the coastal waters of northeast Taiwan during the period 20072010. The community assemblage was composed of 45 species, of which only 14 appeared recurrent in Taiwanese waters. Although there was no clear seasonality, higher richness and abundances occurred in spring and autumn. Examination of potential physical drivers of coastal biomass accumulation did not show any link with water mass transport; instead, peak events were associated with typhoon disturbances, suggesting a potential resource pulse effect.

Description: Comparable values have been obtained for endogenous fecal calcium in cattle by an “isotope dilution” method and a “comparative balance” method. Both procedures involve the use of labeled calcium, but they are different in principle. The “isotope dilution” method offers advantages in being independent of the availability of the dietary calcium and of the uncertainties of balance determinations.

Description: The aim of this study was to examine sponge orange band (SOB) disease affecting the prominent Caribbean sponge Xestospongia muta. Scanning and transmission electron microscopy revealed that SOB is accompanied by the massive destruction of the pinacoderm. Chlorophyll a content and the main secondary metabolites, tetrahydrofurans, characteristic of X. muta, were significantly lower in bleached than in healthy tissues. Denaturing gradient gel electrophoresis using cyanobacteria-specific 16S rRNA gene primers revealed a distinct shift from the Synechococcus/Prochlorococcus clade of sponge symbionts towards several clades of unspecific cyanobacteria, including lineages associated with coral disease (i.e. Leptolyngbya sp.). Underwater infection experiments were conducted by transplanting bleached cores into healthy individuals, but revealed no signs of SOB development. This study provided no evidence for the involvement of a specific microbial pathogen as an etiologic agent of disease; hence, the cause of SOB disease in X. muta remains unidentified.

Description: A PCR protocol for the detection of sulfur-oxidizing bacteria based on soxB genes that are essential for thiosulfate oxidation by sulfur-oxidizing bacteria of various phylogenetic groups which use the 'Paracoccus sulfur oxidation' pathway was developed. Five degenerate primers were used to specifically amplify fragments of soxB genes from different sulfur-oxidizing bacteria previously shown to oxidize thiosulfate. The PCR yielded a soxB fragment of approximately 1000 bp from most of the bacteria. Amino acid and nucleotide sequences of soxB from reference strains as well as from new isolates and environmental DNA from a hydrothermal vent habitat in the North Fiji Basin were compared and used to infer relationships of soxB between sulfur-oxidizing bacteria belonging to various 16S rDNA-based phylogenetic groups. Major phylogenetic lines derived from 16S rDNA were confirmed by soxB phylogeny. Thiosulfate-oxidizing green sulfur bacteria formed a coherent group by their soxB sequences. Likewise, clearly separated branches demonstrated the distant relationship of representatives of alpha-, beta-, and gamma-Proteobacteria including representative species of the former genus Thiobacillus (now Halothiobacillus - gamma-Proteobacteria, Thiobacillus - beta-Proteobacteria and Starkeya - alpha-Proteobacteria). This general picture emerged although apparent evidence for lateral transfer of the soxB gene is indicated and comparison of soxB phylogeny and 16S rDNA phylogeny points to the significance of this gene transfer in hydrothermal vent bacterial communities of the North Fiji Basin.

Description: A bioenergetic model for two narwhal (Monodon monoceros) sub-populations was developed to quantify daily gross energy requirements and estimate the biomass of Greenland halibut (Reinhardtius hippoglossoides) needed to sustain the sub-populations for their 5-month stay on wintering grounds in Baffin Bay. Whales in two separate wintering grounds were estimated to require 700 tonnes (s.e. 300) and 90 tonnes (s.e. 40) of Greenland halibut per day, assuming a diet of 50% Greenland halibut. Mean densities and length distributions of Greenland halibut inside and outside of the narwhal wintering grounds were correlated with predicted whale predation levels based on diving behavior. The difference in Greenland halibut biomass between an area with high predation and a comparable area without whales, approximately 19 000 tonnes, corresponded well with the predicted biomass removed by the narwhal sub-population on a diet of 50–75% Greenland halibut.

Description: Age composition and growth rates of the squid Loligo vulgaris (Lamark, 1797) were studied by examination of growth increments within statoliths of 419 specimens (mantle length, ML, ranging from 32 to 400mm). The squid were obtained by monthly sampling from the catches of commercial trawls off southern Portugal between March and September, 1993. The total number of growth increments in the mounted and ground statoliths was counted using a semi-automatic image analysis system. ML was significantly correlated with both the statolith length, TSL and the number of increments, NI. The female statolith was slightly larger than the male statolith for the same mantle size. Growth rates of individuals showed high variability with an average estimated at 34.6mm month-1 for males and 33.5mm month-1 for females. Growth in length between 70 and 280 days was best described by a power function for both sexes. The growth index of the statolith (TSL/NI) decreased with individual growth. The result may be related with the onset of sexual maturation. L. vulgaris hatched throughout the year with two distinct peaks, in spring which is the main breeding period, and in autumn. The life cycle of the L. vulgaris population on the south Portugese shelf was completed in one year.

Description: Endogenous fecal calcium was estimated directly in normal cattle by a method which consisted of 10 daily intravenous injections of radiocalcium, comparison of the specific activities of blood and feces taken on the 4th to 8th day post-injection, and routine determination of calcium balance. The daily endogenous fecal values for three 8-year-old dairy cows averaged 7 gm and for two yearling Hereford steers about 4 gm. The endogenous fecal calcium was not significantly changed when the dietary calcium was varied from normal to a high level. In two animals on a low calcium diet a decrease in endogenous fecal calcium was indicated.