Abundance of pico- and nanophytoplankton during the Meteor cruise M87/1

In temperate, subpolar and polar marine systems, the classical perception is that diatoms initiate the spring bloom and thereby mark the beginning of the productive season. Contrary to this view, here we document an pre-bloom of pico- and nanophytoplankton prior to the diatom bloom; a period with excess nutrients and deep convection of the water column. During repeated visits to stations in the deep Icelandic and the Norwegian Basins and the shallow Shetland Shelf (26 March to 29 April 2012), we investigated the succession and dynamics of <10 µm phytoplankton. Water samples were collected from CTD rosette 10 L Niskin bottles and fixed in glutaraldehyde (final conc. 5%), flash frozen in liquid Nitrogen and stored at -80°C until analysis.

Sedimentological, biogeomcial and geochronological data of thermokarst lake sediment core PG1967

Ice-rich permafrost landscapes are sensitive to climate and environmental change due to the melt-out of ground ice during thermokarst development. Thermokarst processes in the northern Yukon Territory are currently not well-documented. Lake sediments from Herschel Island (69°36'N; 139°04'W) in the western Canadian Arctic provide a record of thermokarst lake development since the early Holocene. A 727 cm long lake sediment core was analyzed for radiographic images, magnetic susceptibility, granulometry, and biogeochemical parameters (organic carbon, nitrogen, and stable carbon isotopes). Based on eight calibrated AMS radiocarbon dates, the sediment record covers the last ~ 11,500 years and was divided into four lithostratigraphic units (A to D) reflecting different thermokarst stages. Thermokarst initiation at the study area began ~ 11.5 cal ka BP. From ~ 11.5 to 10.0 cal ka BP, lake sediments of unit A started to accumulate in an initial lake basin created by melt-out of massive ground ice and thaw subsidence. Between 10.0 and 7.0 cal ka BP (unit B) the lake basin expanded in size and depth, attributed to talik formation during the Holocene thermal maximum. Higher-than-modern summer air temperatures led to increased lake productivity and widespread terrain disturbances in the lake's catchment. Thermokarst lake development between 7.0 and 1.8 cal ka BP (unit C) was characterized by a dynamic equilibrium, where lake basin and talik steadily expanded into ambient ice-rich terrain through shoreline erosion. Once lakes become deeper than the maximum winter lake ice thickness, thermokarst lake sediments show a great preservation potential. However, site-specific geomorphic factors such as episodic bank-shore erosion or sudden drainage through thermo-erosional valleys or coastal erosion breaching lake basins can disrupt continuous deposition. A hiatus in the record from 1.8 to 0.9 cal ka BP in Lake Herschel likely resulted from lake drainage or allochthonous slumping due to collapsing shore lines before continuous sedimentation of unit D recommenced during the last 900 years.

Sediment and pore water C and N composition of ODP Holes 201-1227A and 201-1230A

This study addresses the problem of diagenetic fractionation of d15N in sedimentary organic matter by constructing isotopic mass balances for the sedimentary nitrogen and pore water ammonium at two Ocean Drilling Program (ODP) sites, 1227 and 1230. At Site 1230, ammonium production flux integrated through the sedimentary column indicates that >60% of organic matter is lost to decomposition. The d15N of pore water ammonium is <0.7 per mil different from that of the sedimentary organic matter, which implies that very little isotopic fractionation is associated with degradation of organic matter at this site. The constant d15N of the solid-phase sedimentary nitrogen through the whole profile supports this conclusion. Atomic C/N ratios (9-12) indicate that organic matter at this site is primarily of marine origin. At Site 1227, the sedimentary organic matter appears to be a mixture of terrestrial and marine components. Ammonium is ~4 heavier than the organic matter. The observed isotopic enrichment of pore water ammonium relative to the sedimentary nitrogen might indicate either the preferential decomposition of isotopically heavier marine fraction of the organic matter, or possibly, a nonsteady-state condition of the ammonium concentration and d15N profiles. Interpretation of the results at Site 1227 is further complicated by the contribution of ammonium with d15N of ~4 per mil that is diffusing upward from Miocene brines.

Epoch, organic carbon and compounds at DSDP Holes 93-605 and 95-613

Twenty-four sediment samples from DSDP Holes 605 (Leg 93) and 613 (Leg 95) on the New Jersey continental rise were analyzed by pyrolysis-gas chromatography. Twelve of these samples were also analyzed by pyrolysis-gas chromatography/mass spectrometry. The degree of preservation of sediment organic matter, as determined by these techniques, helped to distinguish slumped sediments from sediments that have not moved from their original place of deposition. Total levels of pyrolyzable organic material, as determined from pyrolysis-gas chromatography, were low in sediments that were not slumped, indicating that the organic material is highly degraded. Nitrogen- and oxygen-containing compounds were the primary compounds detected by gas chromatography/mass spectrometry (GCMS) analysis of the pyrolyzate of non-slumped sediments. Smaller amounts of aromatic compounds and branched alkanes were also present in some of these samples. In contrast, slumped sediments showed larger amounts of pyrolyzable organic matter, as determined from pyrolysis-gas chromatography, and better preservation of alkyl chains in the sediment organic matter, as suggested by the presence of n-alkanes in GCMS analysis of the pyrolyzate. Better preservation of the organic matter in slumped sediments can be attributed to more moderate bioturbation by bottom-dwelling organisms at the original deposition site.

Organic matter and sediment properties of samples from site GeoB15105 from the Black Sea

Dissolved organic matter (DOM) in marine sediments is a complex mixture of thousands of individual constituents that participate in biogeochemical reactions and serve as substrates for benthic microbes. Knowledge of the molecular composition of DOM is a prerequisite for a comprehensive understanding of the biogeochemical processes in sediments. In this study, interstitial water DOM was extracted with Rhizon samplers from a sediment core from the Black Sea and compared to the corresponding water-extractable organic matter fraction (<0.4 µm) obtained by Soxhlet extraction, which mobilizes labile particulate organic matter and DOM. After solid phase extraction (SPE) of DOM, samples were analyzed for the molecular composition by Fourier Transform Ion-Cyclotron Resonance Mass Spectrometry (FT-ICR MS) with electrospray ionization in negative ion mode. The average SPE extraction yield of the dissolved organic carbon (DOC) in interstitial water was 63%, whereas less than 30% of the DOC in Soxhlet-extracted organic matter was recovered. Nevertheless, Soxhlet extraction yielded up to 4.35% of the total sedimentary organic carbon, which is more than 30-times the organic carbon content of the interstitial water. While interstitial water DOM consisted primarily of carbon-, hydrogen- and oxygen-bearing compounds, Soxhlet extracts yielded more complex FT-ICR mass spectra with more peaks and higher abundances of nitrogen- and sulfur-bearing compounds. The molecular composition of both sample types was affected by the geochemical conditions in the sediment; elevated concentrations of HS- promoted the early diagenetic sulfurization of organic matter. The Soxhlet extracts from shallow sediment contained specific three- and four-nitrogen-bearing molecular formulas that were also detected in bacterial cell extracts and presumably represent proteinaceous molecules. These compounds decreased with increasing sediment depth while one- and two-nitrogen-bearing molecules increased, resulting in a higher similarity of both sample types in the deep sediment. In summary, Soxhlet extraction of sediments accessed a larger and more complex pool of organic matter than present in interstitial water DOM.

(Table 1) Isotopic and geochemical parameters of gas phase from underground fluids of the Baikal rift and its framing

Results of studying isotopic composition of helium in underground fluids of the Baikal-Mongolian region during the last quarter of XX century are summarized. Determinations of 3He/4He ratio in 139 samples of gas phase from fluids, collected at 104 points of the Baikal rift zone and adjacent structures are given. 3He/4He values lie within the range from 1x10**-8 (typical for crustal radiogenic helium) to 1.1x10**-5 (close to typical MORB reservoir). Repeated sampling in some points during more than 20 years showed stability of helium isotopic composition in time in each of them at any level of 3He/4He values. There is no systematic differences of 3He/4He in samples from surface water sources and deeper intervals of boreholes in the same areas. Universal relationship between isotopic composition of helium and general composition of gas phase is absent either, but the minimum 3He/4He values occurred in methane gas of hydrocarbon deposits, whereas in nitrogen and carbon dioxide gases of helium composition varied (in the latter maximum 3He/4He values have been measured). According to N2/Ar_atm ratio nitrogen gases are atmospheric. In carbonic gas fN2/fNe ratio indicates presence of excessive (non-atmogenic) nitrogen, but the attitude CO2/3He differs from one in MORB. Comparison of helium isotopic composition with its concentration and composition of the main components of gas phase from fluids shows that it is formed under influence of fractionation of components with different solubility in the gas-water system and generation/consumption of reactive gases in the crust. Structural and tectonic elements of the region differ from the spectrum of 3He/4He values. At the pre-Riphean Siberian Platform the mean 3He/4He = (3.6+/-0.9)x10**- 8 is very close to radiogenic one. In the Paleozoic crust of Khangay 3He/4He = (16.3+/-4.6)x10**-8, and the most probable estimate is (12.3+/-2.9)x10**-8. In structures of the eastern flank of the Baikal rift zone (Khentei, Dauria) affected by the Mz-Kz activization 3He/4He values range from 4.4x10**-8 to 2.14x10**-6 (average 0.94x10**-6). Distribution of 3He/4He values across the strike of the Baikal rift zone indicates advective heat transfer from the mantle not only in the rift zone, but also much further to the east. In fluids of the Baikal rift zone range of 3He/4He values is the widest: from 4x10**-8 to 1.1x10**-5. Their variations along the strike of the rift zone are clearly patterned, namely, decrease of 3He/4He values in both directions from the Tunka depression. Accompanied by decrease in density of conductive heat flow and in size of rift basins, this trend indicates decrease in intensity of advective heat transfer from the mantle to peripheral segments of the rift zone. Comparing this trend with data on other continental rift zones and mid-ocean ridges leads to the conclusion about fundamental differences in mechanisms of interaction between the crust and the mantle in these environments.

Dissolved nitrogen in soil solution of the Jena Experiment (Main Experiment, year 2002)

This data set contains measurements of dissolved nitrogen (total dissolved nitrogen: TDN, dissolved organic nitrogen: DON, dissolved ammonium: NH4+, and dissolved nitrate: NO3-) in samples of soil water collected from the main experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. In April 2002 glass suction plates with a diameter of 12 cm, 1 cm thickness and a pore size of 1-1.6 µm (UMS GmbH, Munich, Germany) were installed in depths of 10, 20, 30 and 60 cm to collect soil solution. The sampling bottles were continuously evacuated to a negative pressure between 50 and 350 mbar, such that the suction pressure was about 50 mbar above the actual soil water tension. Thus, only the soil leachate was collected. Cumulative soil solution was sampled biweekly and analyzed for nitrate (NO3-) and ammonium (NH4+) concentrations with a continuous flow analyzer (CFA, Skalar, Breda, The Netherlands). Nitrate was analyzed photometrically after reduction to NO2- and reaction with sulfanilamide and naphthylethylenediamine-dihydrochloride to an azo-dye. Our NO3- concentrations contained an unknown contribution of NO2- that is expected to be small. Simultaneously to the NO3- analysis, NH4+ was determined photometrically as 5-aminosalicylate after a modified Berthelot reaction. The detection limits of NO3- and NH4+ were 0.02 and 0.03 mg N L-1, respectively. Total dissolved N in soil solution was analyzed by oxidation with K2S2O8 followed by reduction to NO2- as described above for NO3-. Dissolved organic N (DON) concentrations in soil solution were calculated as the difference between TDN and the sum of mineral N (NO3- + NH4+). In 5% of the samples, TDN was equal to or smaller than mineral N. In these cases, DON was assumed to be zero.

Dissolved nitrogen in soil solution of the Jena Experiment (Main Experiment, year 2003)

This data set contains measurements of dissolved nitrogen (total dissolved nitrogen: TDN, dissolved organic nitrogen: DON, dissolved ammonium: NH4+, and dissolved nitrate: NO3-) in samples of soil water collected from the main experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. In April 2002 glass suction plates with a diameter of 12 cm, 1 cm thickness and a pore size of 1-1.6 µm (UMS GmbH, Munich, Germany) were installed in depths of 10, 20, 30 and 60 cm to collect soil solution. The sampling bottles were continuously evacuated to a negative pressure between 50 and 350 mbar, such that the suction pressure was about 50 mbar above the actual soil water tension. Thus, only the soil leachate was collected. Cumulative soil solution was sampled biweekly and analyzed for nitrate (NO3-) and ammonium (NH4+) concentrations with a continuous flow analyzer (CFA, Skalar, Breda, The Netherlands). Nitrate was analyzed photometrically after reduction to NO2- and reaction with sulfanilamide and naphthylethylenediamine-dihydrochloride to an azo-dye. Our NO3- concentrations contained an unknown contribution of NO2- that is expected to be small. Simultaneously to the NO3- analysis, NH4+ was determined photometrically as 5-aminosalicylate after a modified Berthelot reaction. The detection limits of NO3- and NH4+ were 0.02 and 0.03 mg N L-1, respectively. Total dissolved N in soil solution was analyzed by oxidation with K2S2O8 followed by reduction to NO2- as described above for NO3-. Dissolved organic N (DON) concentrations in soil solution were calculated as the difference between TDN and the sum of mineral N (NO3- + NH4+). In 5% of the samples, TDN was equal to or smaller than mineral N. In these cases, DON was assumed to be zero.

Effect of wheat inclusion and xylanase supplementation of the diet on intestinal enzyme activity, nutrient retention and performance in laying hen from 25 to 47 wks of age

A trial was conducted to examine the effects of increasing levels of wheat in the diet and xylanase (ES) supplementation on nitrogen and ether extract retention, pH of the GIT, productive performance from 25 to 47 wks of age, and enzyme activity at the small intestine level. The basal diets (from 25 to 33 wks and from 33 to 47 wks) consisted of soybean meal and corn, and the wheat was introduced in the experimental diets at expenses of corn, primarily.

Structural behaviour and design criteria of under-deck cable-stayed bridges subjected to seismic action

Under-deck cable-stayed bridges are very effective structural systems for which the strong contribution of the stay cables under live loading allows for the design of very slender decks for persistent and transient loading scenarios. Their behaviour when subjected to seismic excitation is investigated herein and a set of design criteria are presented that relate to the type and arrangement of bearings, the number and configuration of struts, and the transverse distribution of stay cables. The nonlinear behaviour of these bridges when subject to both near-field and far-field accelerograms has been thoroughly investigated through the use of incremental dynamic analyses. An intensity measure that reflects the pertinent contributions to response when several vibration modes are activated was proposed and is shown to be effective for the analysis of this structural type. The under-deck cable-stay system contributes in a very positive manner to reducing the response when the bridges are subject to very strong seismic excitation. For such scenarios, the reduction in the stiffness of the deck because of crack formation, when prestressed concrete decks are used, mobilises the cable system and enhances the overall performance of the system. Sets of natural accelerograms that are compliant with the prescriptions of Eurocode 8 were also applied to propose a set of design criteria for this bridge type in areas prone to earthquakes. Particular attention is given to outlining the optimal strategies for the deployment of bearings

Seasonal evolution of soil respiration in a mixed forestry plantation of walnuts (Juglans × intermedia Carr.) and alders (Alnus cordata (Loisel.) Duby) in Domaine de Restinclières (France)

The ecological intensification of crops is proposed as a solution to the growing demand of agricultural and forest resources, in opposition to intensive monocultures. The introduction of mixed cultures as mixtures between nitrogen fixing species and non nitrogen fixing species intended to increase crop yield as a result of an improvement of the available nitrogen and phosphorus in soil. Relationship between crops have received little attention despite the wide range of advantages that confers species diversity to these systems, such as increased productivity, resilience to disruption and ecological sustainability. Forests and forestry plantations can develop an important role in storing carbon in their tissues, especially in wood which become into durable product. A simplifying parameter to analyze the amount allocated carbon by plantation is the TBCA (total belowground carbon allocation), whereby, for short periods and mature plantations, is admitted as the subtraction between soil carbon efflux and litterfall. Soil respiration depends on a wide range of factors, such as soil temperature and soil water content, soil fertility, presence and type of vegetation, among others. The studied orchard is a mixed forestry plantation of hybrid walnuts(Juglans × intermedia Carr.) for wood and alders (Alnus cordata (Loisel.) Duby.), a nitrogen fixing specie through the actinomycete Frankia alni ((Woronin, 1866) Von Tubeuf 1895). The study area is sited at Restinclières, a green area near Montpellier (South of France). In the present work, soil respiration varied greatly throughout the year, mainly influenced by soil temperature. Soil water content did not significantly influence the response of soil respiration as it was constant during the measurement period and under no water stress conditions. Distance between nearest walnut and measurement was also a highly influential factor in soil respiration. Generally there was a decreasing trend in soil respiration when the distance to the nearest tree increased. It was also analyzed the response of soil respiration according to alder presence and fertilizer management (50 kg N·ha-1·año-1 from 1999 to 2010). None of these treatments significantly influenced soil respiration, although previous studies noticed an inhibition in rates of soil respiration under fertilized conditions and high rates of available nitrogen. However, treatments without fertilization and without alder presence obtained higher respiration rates in those cases with significant differences. The lack of significant differences between treatments may be due to the high coefficient of variation experienced by soil respiration measurements. Finally an asynchronous fluctuation was observed between soil respiration and litterfall during senescence period. This is possibly due to the slowdown in the emission of exudates by roots during senescence period, which are largely related to microbial activity.

Instrument for testing the impact response of different materials. Application to apples and pears

Based on two research projects, a device for testing the response to-impact of fruits and related materials has been designed and tested during the last three years. As it is not related directly to potatoes, this contribution focuses mainly on the principles of impact and static loading and on the description of the device, and the type of results obtained up to now in different fruits.

Neural bruise prediction models for fruit handling and machinery evaluation.

Some neural bruise prediction models have been implemented in the laboratory, for the most traded fruit species and varieties, allowing the prediction of the acceptability or rejectability for damages, with respect to the EC Standards. Different models have been built for both quasi-static (compression) and dynamic (impact) loads covering the whole commercial ripening period of fruits. A simulation process has been developed gathering the information on laboratory bruise models and load sensor calibrations for different electronic devices (IS-100 and DEA-1, for impact and compression loads respectively). Some evaluation methodology has been designed gathering the information on the mechanical properties of fruits and the loading records of electronic devices. The evaluation system allows to determine the current stage of fruit handling process and machinery.