Heavy metal concentrations in soils, vegetation, earthworms and wood mice from Heteren and Plateaux, The Netherlands

Effects of soil properties on the accumulation of metals to wood mice (Apodemus sylvaticus) were evaluated at two sites with different pH and organic matter content of the soil. pH and organic matter content significantly affected accumulation of Cd, Cu, Pb and Zn in earthworms and vegetation. For Cd, Cu and Zn these effects propagated through the food web to the wood mouse. Soil-to-kidney ratios differed between sites: Cd: 0.15 versus 3.52, Cu: 0.37 versus 1.30 and Zn: 0.33-0.83. This was confirmed in model calculations for Cd and Zn. Results indicate that total soil concentrations may be unsuitable indicators for risks that metals pose to wildlife. Furthermore, environmental managers may, unintentionally, change soil properties while taking specific environmental measures. In this way they may affect risks of metals to wildlife, even without changes in total soil concentrations.

Fecal pellets flux at DYFAMED sediment traps

Because zooplankton feces represent a potentially important transport pathway of surface-derived organic carbon in the ocean, we must understand the patterns of fecal pellet abundance and carbon mobilization over a variety of spatial and temporal scales. To assess depth-specific water column variations of fecal pellets on a seasonal scale, vertical fluxes of zooplankton fecal pellets were quantified and their contribution to mass and particulate carbon were computed during 1990 at 200, 500, 1000, and 2000 m depths in the open northwestern Mediterranean Sea as part of the French-JGOFS DYFAMED Program. Depth-averaged daily fecal pellet flux was temporally variable, ranging from 3.04 * 10**4 pellets m**2/d in May to a low of 6.98 * 10**2 pellets m**2/d in September. The peak flux accounted for 50% of the integrated annual flux of fecal pellets and 62% of pellet carbon during only two months in mid-spring (April and May). Highest numerical fluxes were encountered at 1000 m, suggesting fecal pellet generation well below the euphotic zone. However, there was a trend toward lower pellet carbon with increasing depth, suggesting bacterial degradation or in situ repackaging as pellets sink through the water column. At 500 m, both the lowest pellet numerical abundance and carbon flux were evident during the spring peak. Combined with data indicating that numerical and carbon fluxes are dominated at 500 m by a distinct type of pellet found uniquely at this depth, these trends suggest the presence of an undescribed mid-water macro-zooplankton or micro-nekton community. Fecal pellet carbon flux was highest at 200 m and varied with depth independently of overall particulate carbon, which was greatest at 500 m. Morphologically distinct types of pellets dominated the numerical and carbon fluxes. Small elliptical and spherical pellets accounted for 88% of the numerical flux, while larger cylindrical pellets, although relatively rare (<10%), accounted for almost 40% of the overall pellet carbon flux. Cylindrical pellets dominated the pellet carbon flux at all depths except 500 m, where a large subtype of elliptical pellet, found only at that depth, was responsible for the majority of pellet carbon flux. Overall during 1990, fecal pellets were responsible for a depth-integrated annual average flux of 1.03 mgC/m**2/d, representing 18% of the total carbon flux. The proportion of vertical carbon flux attributed to fecal pellets varied from 3 to 35%, with higher values occurring during periods when the water column was vertically mixed. Especially during these times, fecal pellets are a critical conveyor of carbon to the deep sea in this region.

Quantitative component analysis of the coarse fraction of surface sediments from the Persian Gulf

In the Persian Gulf and the Gulf of Oman marl forms the primary sediment cover, particularly on the Iranian side. A detailed quantitative description of the sediment components > 63 µ has been attempted in order to establish the regional distribution of the most important constituents as well as the criteria governing marl sedimentation in general. During the course of the analysis, the sand fraction from about 160 bottom-surface samples was split into 5 phi° fractions and 500 to 800 grains were counted in each individual fraction. The grains were cataloged in up to 40 grain type catagories. The gravel fraction was counted separately and the values calculated as weight percent. Basic for understanding the mode of formation of the marl sediment is the "rule" of independent availability of component groups. It states that the sedimentation of different component groups takes place independently, and that variation in the quantity of one component is independent of the presence or absence of other components. This means, for example, that different grain size spectrums are not necessarily developed through transport sorting. In the Persian Gulf they are more likely the result of differences in the amount of clay-rich fine sediment brought in to the restricted mouth areas of the Iranian rivers. These local increases in clayey sediment dilute the autochthonous, for the most part carbonate, coarse fraction. This also explains the frequent facies changes from carbonate to clayey marl. The main constituent groups of the coarse fraction are faecal pellets and lumps, the non carbonate mineral components, the Pleistocene relict sediment, the benthonic biogene components and the plankton. Faecal pellets and lumps are formed through grain size transformation of fine sediment. Higher percentages of these components can be correlated to large amounts of fine sediment and organic C. No discernable change takes place in carbonate minerals as a result of digestion and faecal pellet formation. The non-carbonate sand components originate from several unrelated sources and can be distinguished by their different grain size spectrum; as well as by other characteristics. The Iranian rivers supply the greatest amounts (well sorted fine sand). Their quantitative variations can be used to trace fine sediment transport directions. Similar mineral maxima in the sediment of the Gulf of Oman mark the path of the Persian Gulf outflow water. Far out from the coast, the basin bottoms in places contain abundant relict minerals (poorly sorted medium sand) and localized areas of reworked salt dome material (medium sand to gravel). Wind transport produces only a minimal "background value" of mineral components (very fine sand). Biogenic and non-biogenic relict sediments can be placed in separate component groups with the help of several petrographic criteria. Part of the relict sediment (well sorted fine sand) is allochthonous and was derived from the terrigenous sediment of river mouths. The main part (coarse, poorly sorted sediment), however, was derived from the late Pleistocene and forms a quasi-autochthonous cover over wide areas which receive little recent sedimentation. Bioturbation results in a mixing of the relict sediment with the overlying younger sediment. Resulting vertical sediment displacement of more than 2.5 m has been observed. This vertical mixing of relict sediment is also partially responsible for the present day grain size anomalies (coarse sediment in deep water) found in the Persian Gulf. The mainly aragonitic components forming the relict sediment show a finely subdivided facies pattern reflecting the paleogeography of carbonate tidal flats dating from the post Pleistocene transgression. Standstill periods are reflected at 110 -125m (shelf break), 64-61 m and 53-41 m (e.g. coare grained quartz and oolite concentrations), and at 25-30m. Comparing these depths to similar occurrences on other shelf regions (e. g. Timor Sea) leads to the conclusion that at this time minimal tectonic activity was taking place in the Persian Gulf. The Pleistocene climate, as evidenced by the absence of Iranian river sediment, was probably drier than the present day Persian Gulf climate. Foremost among the benthonic biogene components are the foraminifera and mollusks. When a ratio is set up between the two, it can be seen that each group is very sensitive to bottom type, i.e., the production of benthonic mollusca increases when a stable (hard) bottom is present whereas the foraminifera favour a soft bottom. In this way, regardless of the grain size, areas with high and low rates of recent sedimentation can be sharply defined. The almost complete absence of mollusks in water deeper than 200 to 300 m gives a rough sedimentologic water depth indicator. The sum of the benthonic foraminifera and mollusca was used as a relative constant reference value for the investigation of many other sediment components. The ratio between arenaceous foraminifera and those with carbonate shells shows a direct relationship to the amount of coarse grained material in the sediment as the frequence of arenaceous foraminifera depends heavily on the availability of sand grains. The nearness of "open" coasts (Iranian river mouths) is directly reflected in the high percentage of plant remains, and indirectly by the increased numbers of ostracods and vertebrates. Plant fragments do not reach their ultimate point of deposition in a free swimming state, but are transported along with the remainder of the terrigenous fine sediment. The echinoderms (mainly echinoids in the West Basin and ophiuroids in the Central Basin) attain their maximum development at the greatest depth reached by the action of the largest waves. This depth varies, depending on the exposure of the slope to the waves, between 12 to 14 and 30 to 35 m. Corals and bryozoans have proved to be good indicators of stable unchanging bottom conditions. Although bryozoans and alcyonarian spiculae are independent of water depth, scleractinians thrive only above 25 to 30 m. The beginning of recent reef growth (restricted by low winter temperatures) was seen only in one single area - on a shoal under 16 m of water. The coarse plankton fraction was studied primarily through the use of a plankton-benthos ratio. The increase in planktonic foraminifera with increasing water depth is here heavily masked by the "Adjacent sea effect" of the Persian Gulf: for the most part the foraminifera have drifted in from the Gulf of Oman. In contrast, the planktonic mollusks are able to colonize the entire Persian Gulf water body. Their amount in the plankton-benthos ratio always increases with water depth and thereby gives a reliable picture of local water depth variations. This holds true to a depth of around 400 m (corresponding to 80-90 % plankton). This water depth effect can be removed by graphical analysis, allowing the percentage of planktonic mollusks per total sample to be used as a reference base for relative sedimentation rate (sedimentation index). These values vary between 1 and > 1000 and thereby agree well with all the other lines of evidence. The "pteropod ooze" facies is then markedly dependent on the sedimentation rate and can theoretically develop at any depth greater than 65 m (proven at 80 m). It should certainly no longer be thought of as "deep sea" sediment. Based on the component distribution diagrams, grain size and carbonate content, the sediments of the Persian Gulf and the Gulf of Oman can be grouped into 5 provisional facies divisions (Chapt.19). Particularly noteworthy among these are first, the fine grained clayey marl facies occupying the 9 narrow outflow areas of rivers, and second, the coarse grained, high-carbonate marl facies rich in relict sediment which covers wide sediment-poor areas of the basin bottoms. Sediment transport is for the most part restricted to grain sizes < 150 µ and in shallow water is largely coast-parallel due to wave action at times supplemented by tidal currents. Below the wave base gravity transport prevails. The only current capable of moving sediment is the Persian Gulf outflow water in the Gulf of Oman.

Producción y comercialización de cubos y pellets de alfalfa : un análisis desde la nueva economía institucional

El desarrollo de los mercados en el ámbito global, hace pensar en la actualidad sobre la existencia de un consumidor global, preocupado por demandar no sólo calidad, sino también seguridad en los productos que consume. Esta nueva característica de los consumidores, abre muchas posibilidades para el desarrollo de bienes y servicios con características que aporten una cuota de valor diferencial, sobre la cual resulte posible sustentar estrategias de negocios que hagan hincapié en esta diferenciación. Este tipo de estrategias, por lo general, se encontrarán sustentadas por productos cuyos procesos involucran activos de elevada especificidad y, en este punto, se torna importante poseer un eficiente diseño organizacional que los proteja de grandes pérdidas de valor. En lo que respecta al mercado de pellets y cubos de alfalfa en particular, donde se proyecta una demanda global creciente, y en el que la Argentina tiene ventajas comparativas a partir de su enorme potencial para el desarrollo de alfalfares de calidad premium, que le permitirían obtener un producto con un diferencial de calidad reconocido en el mercado internacional, surge como interrogante a investigar, si el negocio de pellets y cubos de alfalfa en la Argentina encuentra fortalezas para poder aprovechar las oportunidades que ofrece el mercado mundial y cuáles son las claves a considerar para contar con un diseño organizacional que permita el desarrollo de este negocio. La metodología de estudio consistió, por un lado, en una recopilación de información de fuentes primarias y secundarias, para estudiar el mercado en general y el ambiente comercial en particular, y por otro, en el desarrollo de un análisis a partir del Modelo de Tres Vías de Joskow. A partir del estudio se concluyó que para aprovechar las oportunidades en este negocio, es necesario contar con un diseño organizacional en el que coexistan diferentes formas de gobernancia. De esta forma, y con el objeto de proteger a los activos específicos en su conjunto, se observó que para la producción es necesario adoptar una estructura de gobernancia que tendiera a la integración vertical, mientras que para la comercialización se debe combinar una estructura de gobernancia híbrida que contenga salvaguardas, cuando ésta se orienta al mercado externo, con una estructura de gobernancia regida por el mercado para cuando se comercialice dentro de la Argentina

Radiocarbon dates of Mytilus shells and peat and wood samples collected on Drayton Island

A multidisciplinary study was undertaken at the Qijurittuq Site (IbGk-3) on Drayton Island in Low-Arctic Quebec (Canada) to document the relationships between climatic, environmental, and cultural changes and the choice of Thule/Inuit dwelling style in the eastern Arctic. Several marine terraces were 14C-dated with shells in order to reconstruct the area's uplift (glacioisostatic rebound) curve. Plant macrofossil analysis of peat was conducted to reconstruct past vegetation and, indirectly, past climate. Archaeological surveys and excavations characterized the structure of subterranean sod houses at the Qijurittuq Site and were supplemented with open interviews with Inuit elders for a better understanding of site location and the use of household space. The sites selected for habitation were well-drained sandy marine terraces in a valley sheltered from prevailing winds. Sod houses were in turn made possible by the abundance of driftwood on the island and the presence of nearby peatland. Thule/Inuit people used semi-subterranean houses rather than igloos at the Qijurittuq Site during the dry, cold conditions toward the end of the Little Ice Age. Stable environmental conditions and food supply during winter possibly explain the use of those semipermanent houses on Drayton Island. However, it does not exclude the use of igloos during short expeditions on ice.

Mineralogy of southern Kerguelen Plateau sediments

Kaolinite, goethite, minor hematite, and gibbsite were found in fluvial upper Lower Cretaceous basal sediment from the Southern Kerguelen Plateau, Sites 748 and 750, 55°S latitude. This mineral assemblage, derived from the weathering of basalt, indicates near-tropical weathering conditions with high orographic rainfall, at least 100 cm per year. The climate deteriorated by the Turonian or Coniacian, as indicated by the decline in kaolinite content of this sediment. The Upper Cretaceous sediment at Site 748 consists of 200 m of millimeter-laminated, sparsely fossiliferous, wood-bearing glauconitic siltstone and clay stone with siderite concretions deposited on a shelf below wave base. Some graded and cross beds indicate that storms swept over the shelf and reworked the sediment. Overlying this unit is 300 m of intermittently partly silicified, bryozoan-inoceramid-echinoderm-rich glauconitic packstones, grainstones, and wackestones. The dominant clay mineral in both units is identical to the mineral composition of the glauconite pellets: randomly interstratified smectite-mica. The clay fraction has a higher percent of expandable layers than the mineral of the glauconite pellets, and the clay of the underlying subunit has a higher percentage of expandable layers than the clay of the carbonate subunit. Potassium levels mirror these mineral variations, with higher K levels in minerals that have a lower percentage of expandable layers. The decrease in expandability of the mineral in the upper subunit is attributed to diagenesis, the result of higher porosity.

Carbon 14 age dating of wood samples from the Alps

Glacially deformed pieces of wood, organic lake sediments and clasts of reworked peat have been collected in front of Alpine glaciers since AD 1990. The palaeoglaciological interpretation of these organic materials is related to earlier phases of glacier recession surpassing that of today's shrunken glaciers and to tree growth and peat accumulation in the valleys now occupied by the glaciers. Glacial transport of the material is indicated by wood anatomy, incorporated silt, sand and gravel particles, missing bark and deformed treerings. A total of 65 samples have been radiocarbon dated so far, and clusters of dates provide evidence of eight phases of glacier recession: 9910-9550, 9010-7980, 7250-6500, 6170-5950, 5290-3870, 3640-3360, 2740-2620 and 1530-1170 calibrated years BP. Allowing for the timelag between climatic fluctuations, glacier response and vegetation colonization, these recession phases may lag behind climatic changes by 100-200 years.

Biogeochemical measurements associated to deep-sea wood falls

Large organic food falls to the deep sea - such as whale carcasses and wood logs - support the development of reduced, sulfidic niches in an otherwise oxygenated, oligotrophic deep-sea environment. These transient hot spot ecosystems may serve the dispersal of highly adapted chemosynthetic organisms such as thiotrophic bivalves and siboglinid worms. Here we investigated the biogeochemical and microbiological processes leading to the development of sulfidic niches. Wood colonization experiments were carried out for the duration of one year in the vicinity of a cold seep area in the Nile deep-sea fan (Eastern Mediterranean) at depths of 1690 m. Wood logs were deployed in 2006 during the BIONIL cruise (RV Meteor M70/2 with ROV Quest, Marum, Germany) and sampled in 2007 during the Medeco-2 cruise (RV Pourquoi Pas? with ROV Victor 6000, Ifremer, France). Wood-boring bivalves played a key role in the initial degradation of the wood, the dispersal of wood chips and fecal matter around the wood log, and the provision of colonization surfaces to other organisms. Total oxygen uptake measured with a ROV-operated benthic chamber module was higher at the wood (0.5 m away) in contrast to 10 m away at a reference site (25 mmol m-2 d-1 and 1 mmol m-2 d-1, respectively), indicating an increased activity of sedimentary communities around the wood falls. Bacterial cell numbers associated with wood increased substantially from freshly submerged wood to the wood chip/fecal matter layer next to the wood experiments, as determined with Acridine Orange Direct Counts (AODC) and DAPI-stained counts. Microsensor measurements of sulfide, oxygen and pH were conducted ex situ. Sulfide fluxes were higher at the wood experiments when compared to reference measurements (19 and 32 mmol m-2 d-1 vs. 0 and 16 mmol -2 d-1, respectively). Sulfate reduction (SR) rates at the wood experiments were determined in ex situ incubations (1.3 and 2.0 mmol m-2 d-1) and fell into the lower range of SR rates previously observed from other chemosynthetic habitats at cold seeps. There was no influence of wood deposition on phosphate, silicate and nitrate concentrations, but ammonium concentrations were elevated at the wood chip-sediment boundary layer. Concentrations of dissolved organic carbon were much higher at the wood experiments (wood chip-sediment boundary layer) in comparison to measurements at the reference sites, which may indicate that cellulose degradation was highest under anoxic conditions and hence enabled by anaerobic benthic bacteria, e.g. fermenters and sulfate reducers. Our observations demonstrate that, after one year, the presence of wood at the seafloor had led to the creation of sulfidic niches, comparable to what has been observed at whale falls, albeit at lower rates.

Production, oxygen uptake, and sinking velocity of copepod fecal pellets originated from the central North Sea

Production, oxygen uptake, and sinking velocity of copepod fecal pellets egested by Temora longicornis were measured using a nanoflagellate (Rhodomonas sp.), a diatom (Thalassiosira weissflogii), or a coccolithophorid (Emiliania huxleyi) as food sources. Fecal pellet production varied between 0.8 pellets ind**-1 h**-1 and 3.8 pellets ind**-1 h**-1 and was significantly higher with T. weissflogii than with the other food sources. Average pellet size varied between 2.2 x 10**5 µm**3 and 10.0 x 10**5 µm**3. Using an oxygen microsensor, small-scale oxygen fluxes and microbial respiration rates were measured directly with a spatial resolution of 2 µm at the interface of copepod fecal pellets and the surrounding water. Averaged volume-specific respiration rates were 4.12 fmol O2 µm**-3 d**-1, 2.86 fmol O2 µm**-3 d**-1, and 0.73 fmol O2 µm**-3 d**-1 in pellets produced on Rhodomonas sp., T. weissflogii, and E. huxleyi, respectively. The average carbon-specific respiration rate was 0.15 d**-1 independent on diet (range: 0.08-0.21 d**-1). Because of ballasting of opal and calcite, sinking velocities were significantly higher for pellets produced on T. weissflogii (322 +- 169 m d**-1) and E. huxleyi (200 +- 93 m d**-1) than on Rhodomonas sp. (35 +- 29 m d**-1). Preservation of carbon was estimated to be approximately 10-fold higher in fecal pellets produced when T. longicornis was fed E. huxleyi or T. weissflogii rather than Rhodomonas sp. Our study directly demonstrates that ballast increases the sinking rate of freshly produced copepod fecal pellets but does not protect them from decomposition.