Estimation of the normal boiling point of organic compounds via group contributions

The normal boiling point is a fundamental thermo-physical property, which is important in describing the transition between the vapor and liquid phases. Reliable method which can predict it is of great importance, especially for compounds where there are no experimental data available. In this work, an improved group contribution method, which is second order method, for determination of the normal boiling point of organic compounds based on the Joback functional first order groups with some changes and added some other functional groups was developed by using experimental data for 632 organic components. It could distinguish most of structural isomerism and stereoisomerism, which including the structural, cis- and trans- isomers of organic compounds. First and second order contributions for hydrocarbons and hydrocarbon derivatives containing carbon, hydrogen, oxygen, nitrogen, sulfur, fluorine, chlorine and bromine atoms, are given. The fminsearch mathematical approach from MATLAB software is used in this study to select an optimal collection of functional groups (65 functional groups) and subsequently to develop the model. This is a direct search method that uses the simplex search method of Lagarias et al. The results of the new method are compared to the several currently used methods and are shown to be far more accurate and reliable. The average absolute deviation of normal boiling point predictions for 632 organic compounds is 4.4350 K; and the average absolute relative deviation is 1.1047 %, which is of adequate accuracy for many practical applications.

The California current predator diet database: synthesis of common forage species

Characterization of the diets of upper-trophic predators is a key ingredient in management including the development of ecosystem-based fishery management plans, conservation efforts for top predators, and ecological and economic modeling of predator prey interactions. The California Current Predator Diet Database (CCPDD) synthesizes data from published records of predator food habits over the past century. The database includes diet information for 100+ upper-trophic level predator species, based on over 200 published citations from the California Current region of the Pacific Ocean, ranging from Baja, Mexico to Vancouver Island, Canada. We include diet data for all predators that consume forage species: seabirds, cetaceans, pinnipeds, bony and cartilaginous fishes, and a predatory invertebrate; data represent seven discrete geographic regions within the CCS (Canada, WA, OR, CA-n, CA-c, CA-s, Mexico). The database is organized around predator-prey links that represent an occurrence of a predator eating a prey or group of prey items. Here we present synthesized data for the occurrence of 32 forage species (see Table 2 in the affiliated paper) in the diet of pelagic predators (currently submitted to Ecological Informatics). Future versions of the shared-data will include diet information for all prey items consumed, not just the forage species of interest.

(Table 1) Lipid and organochlorine content in blood of common eiders (Somateria mollissima) in Svalbard

Female common eiders (Somateria mollissima) starve during the nesting stage and may lose 30-45% of their initial body mass, mostly through lipid mobilization. In this study, the effects of fasting on the blood concentrations of three lipid-soluble organochlorines (OCs: polychlorinated biphenyl [PCB]-153; 1-dichloro-2,2-bis (p-chlorophenyl) ethylene [p,p'-DDE]; and hexachlorobenzene [HCB]) were examined in eiders breeding in the high Arctic. Blood samples were taken from females (n = 47) at day 5 and day 20 of the incubation period. The mean wet weight concentrations of PCB-153 and p,p'-DDE increased strongly between day 5 and day 20 (3.6 and 8.2-fold, respectively), while HCB increased less (1.7-fold). There was a strong negative association between daily increase in PCB-153 and clutch size, and a weaker relationship for p,p'-DDE, suggesting that maternal transfer to the eggs is a significant pathway of elimination of OCs in eiders. Moreover, poor body condition (body mass controlled for body size) late in the incubation period was associated with strong daily increase of both p,p'-DDE and PCB-153, which may suggest that the release of these compounds increases when lipid reserves become depleted. For HCB, the increase was mainly associated with increase in blood lipid concentrations, and weakly to the amount of burned lipids. The causes for the differences between the compounds are, however, poorly understood. Although the absolute levels of OCs in eiders were relatively low, their rapid build-up during incubation is worrying as it coincides with poor body condition and weakened immune systems.

Data compilation on the biological response to ocean acidification: environmental and experimental context of data sets and related literature

The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.

(Table T1) Geochemical composition of tochilinite and related minerals of ODP Hole 173-1068A

Tochilinite (approximately FeS(Mg,Fe)(OH)2) is locally abundant in Hole 1068A serpentinites from Cores 173-1068A-21R and 22R. It occurs in veins, as fillings in void space, and in intergrowths with serpentine and andradite. An apparently related mineral, but with Ca and Al largely replacing Mg, occurs in association with, and possibly as a replacement of, pyrrhotite in serpentinite breccias from the bottom of Core 173-1068A-20R. The transition from Mg-Fe-rich brucite tochilinites to Ca- and S-rich carbonate tochilinites is consistent with increasing sulfur and oxygen activity upsection. Tochilinite has been reported at other sites on the Iberia Abyssal Plain and is abundant to the point of being a rock-forming mineral in several samples from Site 1068. Rather than being a mineralogical curiosity, tochilinite appears to be common and a major sink for sulfur in the upper serpentinites of the Iberia Abyssal Plain.

Pore water methane characteristics and sulphate reduction rates of ODP Leg 164 sediments

Anaerobic methane oxidation (AMO) was characterized in sediment cores from the Blake Ridge collected during Ocean Drilling Program (ODP) Leg 164. Three independent lines of evidence support the occurrence and scale of AMO at Sites 994 and 995. First, concentration depth profiles of methane from Hole 995B exhibit a region of upward concavity suggestive of methane consumption. Diagenetic modeling of the concentration profile indicates a 1.85-m-thick zone of AMO centered at 21.22 mbsf, with a peak rate of 12.4 nM/d. Second, subsurface maxima in tracer-based sulfate reduction rates from Holes 994B and 995B were observed at depths that coincide with the model-predicted AMO zone. The subsurface zone of sulfate reduction was 2 m thick and had a depth integrated rate that compared favorably to that of AMO (1.3 vs. 1.1 nmol/cm**2/d, respectively). These features suggest close coupling of AMO and sulfate reduction in the Blake Ridge sediments. Third, measured d13CH4 values are lightest at the point of peak model-predicted methane oxidation and become increasingly 13C-enriched with decreasing sediment depth, consistent with kinetic isotope fractionation during bacterially mediated methane oxidation. The isotopic data predict a somewhat (60 cm) shallower maximum depth of methane oxidation than do the model and sulfate reduction data.

Response of nannoplankton to major changes in sea-surface temperature at the South Chatham Rise, southeastern New Zealand

A high-resolution history of paleoceanographic changes in the subpolar waters of the southern margin of the Subtropical Convergence Zone during the last 130 kyr, is present in foraminiferal assemblages of DSDP Site 594. The foraminifera indicate that sea-surface temperatures during the Last Interglacial Climax were warmer than today, and that between substage 5d through to the end of isotope stage 2, temperatures were mostly cooler than Holocene temperatures. The paleotemperatures suggest that (1) the Subtropical Convergence was located over the site during substage 5e, later moving further north, then moving southwards to near the site during the Holocene, and (2) the Polar Front was positioned over the Site during glacial stages 6, 4, 2 and possibly parts of stage 3. Several major events are indicated by the nannofloral assemblages during these large changes in sea-surface temperature and associated reorganization of ocean circulation. First, the time-progressive trends between E. huxleyi and medium to large Gephyrocupsa are unique to this site, with E. huxleyi dominating over medium Gephyrocupsa during stages 5c-a, middle part of stage 4 and after the middle point of stage 3. This unusual trend may (at least partly) be caused by the shift of the Polar Front across the site. Second, upwelling flora (E. huxleyi and small placoliths) increase in abundance during stages 1, 3 and 5, suggesting that upwelling or disturbance of water stratification took place during the interglacials. Thirdly, there are no significant differences between the distribution patterns of the various morphotypes of medium to large Gephyrocupsu, and the combined value of all medium Gephyrocupsu increases in abundance during glacials (stages 2 and 4 and the end of stage 6), similar to the abundance trends in benthic foraminifera. Finally, subordinate nannofossil taxa also show distinctive climatic trends during the last glacial cycle: (1) Syrucosphaera spp. are present in increased abundance during warmer extremes in climate (substages 5e, 5a, and stage 1); (2) Coccolithus pelagicus and Culcidiscus leptoporus dominate the subordinate nannofossil taxa, and their relative proportions seem to provide a useful paleoceanographic index, with C. pelagicus dominating when the Polar Front Zone is over the site (stages 6, 4 and 2), whilst C. leptoporus is relatively more abundant when the STC is positioned over the site (stages 1 and 5e). Increased abundance of C. pelagicus also can indicate intensified coastal upwelling.