Planktonic primary production in the German Wadden Sea

By combining weekly data of irradiance, attenuation and chlorophylla concentrations with photosynthesis (P) versus light intensity(E) curve characteristics, the annual cycle of planktonic primaryproduction in the estuarine part of the Northfrisian WaddenSea was computed for a 2 year period. Daily water column particulategross production ranged from 5 to 2200 mg C m^–2 day^–1and showed a seasonal pattern similar to chlorophyll a. Budgetcalculation yielded annual gross particulate primary productionsof 124 and 176 g C m^–2 year^–1 in 1995 and 1996,respectively. Annual amounts of phytoplankton respiration, calculatedaccording to a two-compartment model of Langdon [in Li,W.K.W.and Maestrini,S.Y. (eds), Measurement of Primary Productionfrom the Molecular to the Global Scale. International Councilfor the Exploration of the Sea, Copenhagen, 1993, pp. 20–36],and dissolved production in 1996, were both in the range of24–39 g C m^–2 year^–1. Annual total net productionwas thus very similar to particulate gross production (127 and177 g C m^–2 year^–1 in 1995 and 1996, respectively).Phytoplankton growth was low or even negative in winter. Inspring and summer, production/biomass (Pr/B) ratios varied from0.2 up to 1.7. Phytoplankton growth during the growth seasonalways surpassed average flushing time in the area, thus underliningthe potential of local phytoplankton bloom development in thispart of the Wadden Sea. The chlorophyll-specific maximum photosyntheticrate (P^B_max) ranged from 0.8 to 9.9 mg C mg^–1 Chl h^–1and was strongly correlated with water temperature (r² = 0.67).By contrast, there was no clear seasonal cycle in ^B, which rangedfrom 0.007 to 0.039 mg C mg^–1 Chl h^–1 (µmolphotons m^–2 s^–1)^–1. Its variability was muchless than P^B_max and independent of temperature. The magnitudeand part of the variability of P^B_max and ^B are presumably causedby changes in species composition, as evidenced from the rangeof these parameters found among 10 predominant diatom speciesisolated from the Wadden Sea. The ratio of average light conditionsin the water column (E_av) to the light saturation parameterE_k indicates that primary production in the Wadden Sea regionunder study is predominantly controlled by light limitationand that nutrient limitation was likely to occur for a few hoursper day only during 5 (dissolved inorganic nitrogen) to 10 (PO₄,Si) weeks in the 2 year period investigated.     

The ontogeny of nasal floor shape variation in extant humans

Variation in nasal floor topography has generated both neontological and paleontological interest. Three categories of nasal floor shape (Franciscus: J Hum Evol 44 (2003) 699–727) have been used when analyzing this trait in extant humans and fossil Homo: flat, sloped, and depressed (or “bi‐level”). Variation in the frequency of these configurations within and among extant and fossil humans has been well‐documented (Franciscus: J Hum Evol 44 (2003) 699–727; Wu et al.: Anthropol Sci 120 (2012) 217–226). However, variation in this trait in Homo has been observed primarily in adults, with comparatively small subadult sample sizes and/or large age gradients that may not sufficiently track key ontogenetic changes. In this study, we investigate the ontogeny of nasal floor shape in a relatively large cross‐sectional age sample of extant humans (n = 382) ranging from 4.0 months fetal to 21 years post‐natal. Results indicate that no fetal or young infant individuals possess a depressed nasal floor, and that a depressed nasal floor, when present (ca. 21% of the sample), does not occur until 3.0 years postnatal. A canonical variates analysis of maxillary shape revealed that individuals with depressed nasal floors were also characterized by relatively taller anterior alveolar regions. This suggests that palate remodeling at about 3.0–3.5 years after birth, under the influence of tooth development, strongly influences nasal floor variation, and that various aspects of dental development, including larger crown/root size, may contribute to the development of a depressed nasal floor. These results in extant humans may help explain the high frequency of this trait found in Neandertal and other archaic Homo maxillae. Am J Phys Anthropol 155:369–378, 2014. © 2014 Wiley Periodicals, Inc.     

Comparison of two different modes of UV-B irradiation on synthesis of some cellular substances in the cyanobacterium <Emphasis Type="Italic">Synechocystis</Emphasis> sp. PCC6803

Two different modes of UV-B irradiation of the cyanobacterium Synechocystis sp. PCC 6803 are compared: turbidostatic control and additional physiostatic control. Under turbidostatic control, the cells were exposed to different constant UV-B irradiances, whereas under physiostatic control, an electronic control loop modulated UV-B irradiance in such a way that photosynthetic efficiency ϕ _PSII was kept constant at a fixed set point. The UV-B-induced stimulation of the synthesis of pigments, α-tocopherol, and the antioxidative potential of methanolic soluble components of Synechocystis showed significant differences depending on the mode of irradiation, even though the overall doses were equal. For example, compared to the initial values, the concentrations of myxoxanthophyll and zeaxanthin increased to 226–244% and 453% upon constant UV-B irradiation in turbidostatic processes, whereas maxima of 600% and 740% were reached in turbidostatic process with additional physiostatic control. The α-tocopherol concentration increased under constant UV-B irradiances, up to a maximum of 150%. Under physiological control, however, maximum increases of 390% over the initial values were measured. Furthermore, a reaction scheme is given explaining the higher yield under physiostatic control.     

Synthesis and structure-activity relationship of new 1,5-dialkyl-1,5-benzodiazepines as cholecystokinin-2 receptor antagonists

This article deals with the synthesis and the activities of some 1,5-dialkyl-3-arylureido-1,5-benzodiazepin-2,4-diones which were prepared as potential CCK2 antagonists, with the intention to find a possible follow up of our lead compound GV150013, showing an improved pharmacokinetic profile. The phenyl ring at N-5 was replaced with more hydrophilic substituents, like alkyl groups bearing basic functions. In some cases, the resolution of the racemic key intermediates 3-amino-benzodiazepines was also accomplished. Among the compounds synthesized and characterised so far in this class, the 5-morpholinoethyl derivative 54, was selected as potential follow up of GV150013 and submitted for further evaluation.     

Prevalence of Salmonella in Australian reptiles

From January 2007 until June 2008, 504 reptiles of four families and 57 species were examined for Salmonella by using cloacal or intestinal swabs. Salmonella was identified in 139 (28%) of the 504 animals tested. Of the 504 reptiles examined, 210 were captive and 294 were wild. Ninety-eight (47%) of the captive reptiles were shedding Salmonella at the time of sampling. In contrast, only 41 (14%) of the wild reptiles were shedding Salmonella. The higher prevalence of Salmonella in captive reptiles was statistically significant (P<0.0001). No Salmonella was found in 60 wild, freshwater chelonians or 48 wild southern water skinks (Eulamprus heatwolei). Our results suggest that some species of wild reptiles in Australia are not natural carriers of Salmonella and that diet and captivity may influence Salmonella excretion in other species.     

Internal nasal floor configuration in Homo with special reference to the evolution of Neandertal facial form

The presence of a steeply sloping or depressed nasal floor within the nasal cavity of Neandertals is frequently mentioned as a likely specialization or autapomorphy. The depressed nasal floor has also been seen as contributing to a relatively more capacious nasal cavity in Neandertals, which is tied to cold-climate respiratory adaptation and energetics. These observations have been limited largely to a relatively few intact crania, and the character states associated with this trait have not been as precisely codified or analyzed as those published for Plio-Pleistocene hominins (McCollum et al., 1993, J. Hum. Evol. 24, 87; McCollum, 2000, Am. J. Phys. Anthrop. 112, 275).This study examines the internal nasal floor topography in complete crania and isolated maxillae in European, west Asian, and African fossil Homo (n=158) including 25 Neandertals, and a wide range of recent humans from Europe, the Near East, and Africa (n=522). The configuration of the internal nasal floor relative to the nasal cavity entrance is codified as: 1) level, forming a smooth continuous plane; 2) sloped or mildly stepped; or 3) bilevel with a pronounced vertical depression. The frequency of these nasal floor configurations, and their relationship to both nasal margin cresting patterning and a comprehensive set of nasofacial metrics is examined.Neandertals show a high frequency of the bilevel (depressed) configuration in both adults and subadults (80%), but this configuration is also present in lower frequencies in Middle Pleistocene African, Late Pleistocene non-Neandertal (Skhul, Qafzeh), and European Later Upper Paleolithic samples (15%-50%). The bilevel configuration is also present in lower frequencies (ca. 10%) in all recent human samples, but attains nearly 20% in some sub-Saharan African samples. Across extinct and extant Homo (excluding Neandertals), internal nasal floor configuration is not associated with piriform aperture nasal margin patterning, but the two are strongly linked in Neandertals. Variation in internal nasal floor configuration in recent humans is primarily associated with internal nasal fossa breadth and nasal bridge elevation, whereas in fossil hominins, it is associated primarily with variation in facial height. Cold-climate and activity-related thermal adaptation as an explanation for the high frequency of pronounced nasal floor depression in Neandertals is inconsistent with all available data. Alternatively, variation in internal nasal floor configuration is more likely related to stochastically derived populational differences in fetal nasofacial growth patterns that do not sharply differentiate genus Homo taxa (i.e., cladistically), but do phenetically differentiate groups, in particular the Neandertals, especially when considered in combination with other nasofacial features.     

Variation in human nasal height and breadth

It has been suggested that the long-standing association of variability in the human nasal index [100 × (nasal breadth)/(nasal height)] with climatic variation is spurious evidence for natural selection in humans (Hoyme, 1965; St. Hoyme and Iscan, 1989). The argument is based principally on the observation that nasal height is globally more variable than nasal breadth, with nasal breadth thus contributing little to variation in the index. This argument does not take into account the confounding effect of absolute size of these variables on their variances. In this study we compare the intrinsic variation in skeletal nasal height and breadth within and among 26 mixed-sex populations (N = 2,408) at globally diverse localities (Howells, 1989), using 2 × 2 variance-covariance matrices of the logarithmically transformed variates. Hypothesis tests for homogeneity of matrices and equalvariance/equal-covariance indicate that the intrinsic variation in nasal breadth is greater than that for nasal height within populations, and that nasal breadth and nasal height exhibit equivalent intrinsic variation among populations. The argument that nasal breadth contributes little to the worldwide variation in the human nasal index is rejected. Given our present understanding of nasal physiological morpho-function, these results support, but do not demonstrate, an adaptive role for human nasal index variation. Promising methods for elucidating natural selection on human nasal form are suggested.     

Demographic and Phenotypic Effects of Human Mediated Trophic Subsidy on a Large Australian Lizard (Varanus varius): Meal Ticket or Last Supper?

Humans are increasingly subsidizing and altering natural food webs via changes to nutrient cycling and productivity. Where human trophic subsidies are concentrated and persistent within natural environments, their consumption could have complex consequences for wild animals through altering habitat preferences, phenotypes and fitness attributes that influence population dynamics. Human trophic subsidies conceptually create both costs and benefits for animals that receive increased calorific and altered nutritional inputs. Here, we evaluated the effects of a common terrestrial human trophic subsidies, human food refuse, on population and phenotypic (comprising morphological and physiological health indices) parameters of a large predatory lizard (～2 m length), the lace monitor (Varanus varius), in southern Australia by comparison with individuals not receiving human trophic subsidies. At human trophic subsidies sites, lizards were significantly more abundant and their sex ratio highly male biased compared to control sites in natural forest. Human trophic subsidies recipient lizards were significantly longer, heavier and in much greater body condition. Blood parasites were significantly lower in human trophic subsidies lizards. Collectively, our results imply that human trophic subsidized sites were especially attractive to adult male lace monitors and had large phenotypic effects. However, we cannot rule out that the male-biased aggregations of large monitors at human trophic subsidized sites could lead to reductions in reproductive fitness, through mate competition and offspring survival, and through greater exposure of eggs and juveniles to predation. These possibilities could have negative population consequences. Aggregations of these large predators may also have flow on effects to surrounding food web dynamics through elevated predation levels. Given that flux of energy and nutrients into food webs is central to the regulation of populations and their communities, we advocate further studies of human trophic subsidies be undertaken to evaluate the potentially large ecological implications of this significant human environmental alteration.     

The effect of substratum type, orientation and depth on the development of bacterial deep-sea biofilm communities grown on artificial substrata deployed in the Eastern Mediterranean

An increasing number of deep-sea studies have highlighted the importance of deep-sea biofouling, especially in relation to the protection of deep-sea instruments. In this study, the microbial communities developed on different substrata (titanium, aluminum, limestone, shale and neutrino telescope glass) exposed for 155 days at different depths (1500?m, 2500?m, 3500?m and 4500 m) and positions (vertical and horizontal) in the Eastern Mediterranean Deep Sea were compared. Replicated biofilm samples were analyzed using a Terminal Restriction Fragment Length Polymorphisms (T-RFLP) method. The restriction enzymes CfoI and RsaI produced similar total numbers (94, 93) of different T-RFLP peaks (T-RFs) along the vertical transect. In contrast, the mean total T-RF number between each sample according to substratum type and depth was higher in more samples when CfoI was used. The total species richness (S) of the bacterial communities differed significantly between the substrata, and depended on the orientation of each substratum within one depth and throughout the water column (ANOVA). T-RFLP analyses using the Jaccard similarity index showed that within one depth layer, the composition of microbial communities on different substrata was different and highly altered among communities developed on the same substratum but exposed to fouling at different depths. Based on Multidimensional Scaling Analyses (MDS), the study suggests that depth plays an important role in the composition of deep-sea biofouling communities, while substratum type and orientation of substrata throughout the water column are less important. To the authors' knowledge, this is the first study of biofilm development in deep waters, in relation to the effects of substratum type, orientation and depth.