The source of raw materials for Roman pottery from Leptiminus,Tunisia

Leptiminus, a Roman port city on the west coast of Tunisia, North Africa, exported olive oil and a garum fish paste to Rome. Excavations have uncovered many facilities including kilns and a potter's workshop, indicating an extensive ceramic industry. The vessels, manufactured at Leptiminus, included African red‐slip fineware, coarseware, and amphorae. A petrographic study of pottery sherds showed them to contain very similar temper, rounded aeolian sand grains and limestone, but varying in proportions to produce different textures. An investigation of the source of raw materials for the pottery found three distinct types of clay within a 50 km radius of Leptiminus: grey Miocene, brown Pliocene, and green Late Pliocene clay. Statistical analysis of trace element compositions, using induced neutron activation, of clays and sherds showed that the Pliocene brown clay was used to create all types of pottery. The specific clay horizon, used in Roman times, has apparently been removed by quarrying. However, a lateral continuation of this bed was found 7 m beneath the Leptiminus site 290. © 2002 Wiley Periodicals, Inc.     

Sampling Method for the Determination of Total Inorganic Carbon (TIC) in Strongly Acidic Waters

Samples from extremely acidic waters should be taken using the introduced syringe technique avoiding atmospheric contact to minimize CO2 evaporation from the samples. The syringe technique inclusive manual injection enables the determination of TIC in acid waters with high precision and accuracy. If a TOC analyser with a small sample volume is used, the vials should be filled directly inside the water sampler without air bubbles, covered with aluminium foil and transported at ambient water temperatures. If an autosampler is used, partial selection of the vials increases the stability of the results. Care should be taken that samples can be analysed within a short time.     

Vertical accretion rates in fluvial systems: ­a comparison of volumetric and depth‐based estimates

A wide range of approaches has been adopted for collecting and reporting vertical accretion rates, hence evaluation of results from different catchments, or even from different reaches within the same basin, is difficult as they may not be directly comparable. The present study compares depth‐ and volume‐based estimates of sediment accumulation for well‐dated vertical accretion sequences at Broomhaugh Island in the Tyne basin, northern England. High resolution dating control (based on heavy metal stratigraphy and cartography) coupled with detailed reconstruction of channel geometry allows accumulation rates to be calculated for the last 300–400 years. The results show a marked disparity in the magnitude and pattern of vertical accretion rates between the two approaches. The average annual thickness of sediment increases progressively, with a six‐fold difference between the seventeenth and twentieth centuries. The volume figures are more consistent, with a two‐fold difference between the highest and lowest rates, both of which occurred in the twentieth century. A major control on vertical accretion is found to be changing channel shape and capacity. Enlargement of the channel by 76 per cent since the seventeenth century, associated with channel bed incision, has resulted in fewer overbank flows. Hence floods, with their associated suspended sediment loads, which once inundated the floodplain are now confined within the channel. The reduced areal extent of surfaces available for deposition has resulted in greater annual thickness of sediment accumulated, despite an overall reduction in volume. This study emphasizes that caution is needed when attempting to identify causal linkages between changes in sedimentation rates and catchment land use and/or climatic factors and the geomorphological setting of the site must be taken into account. Copyright © 2000 John Wiley & Sons, Ltd.     

Coral reef productivity and diversity—Contributions from enhanced photosynthesis via demand for carbohydrate from the host

Coral reefs’ high productivity has been attributed mainly to photosymbioses between the coral animal and algae of the family Symbiodiniaceae, with recognition that the host can increase algal photosynthesis by concentrating nutrients and enhancing the efficiency of light absorption. Here, we propose that an additional effect, consumption of carbohydrate by the host, may also enhance algal photosynthesis. We examine evidence from symbiosis between terrestrial plants and root fungi that indicates a link between carbohydrate consumption by the symbiotic partner and photosynthetic upregulation in the plant system. In addition, we review evidence from free-living algae manipulated to exude carbohydrate into the external medium, which was associated with strong upregulation of photosynthetic capacity. We offer suggestions on how host-induced carbohydrate release may increase photosynthesis rates in the symbionts in the intact photosymbiosis and how this relationship evolved.     

The colonization of macroalgal wrack by the meiofauna in the Arctic intertidal

A litter bag experiment was performed on a wrack-loaded beach in Hornsund (southern Spitsbergen) to study the decay rate of stranded macroalgae and their colonization by meiofauna. The average monthly loss of macroalgal dry mass was 45 ± 5%. The composition of the wrack-associated fauna was similar to those reported from other world regions. Nematodes composed of bacterivorous rhabditids and monhysterids were the numerically dominant taxon (>99% of the community). High nematode densities averaging 35,000 ind. per litter bag (6,500 ind g⁻¹ dwt) indicate their skills for rapid colonization and successful exploitation of the short-lived habitat established on an Arctic beach. We suggest that stranded macroalgae may play a role as a potential hotspot for nematodes and microbial processes in the Arctic coastal ecosystem. It is also suggested that wrack position on the beach profile which resulted in different wrack-age and moisture content may affect the composition and diversity of the wrack-associated meiofauna.     

Occupational health and safety hazards in Atlantic Canadian aquaculture: Laying the groundwork for prevention

The growing aquaculture industry is projected to feature ever more prominently in the lives and economies of rural coastal communities in Atlantic Canada and around the world. Both private industry and government have a responsibility to ensure employment opportunities created in aquaculture take place in healthy, safe environments. However, systematic occupational health and safety (OHS) research within this industry, an important prevention tool, is still in its infancy. With particular emphasis on marine aquaculture in Atlantic Canada, we provide a detailed outline of the structure of the industry from feed production through to processing, identify potential OHS hazards associated with each of these activities and make recommendations for future research and action.     

Asian monsoon climate during the Last Glacial Maximum: palaeo‐data–model comparisons

The Last Glacial Maximum (LGM) (23–19 ka BP) in the Asian monsoon region is generally described as cool and dry, due to a strong winter monsoon. More recently, however, palaeo‐data and climate model simulations have argued for a more variable LGM Asian monsoon climate with distinct regional differences. We compiled, evaluated, and partly re‐assessed proxy records for the Asian monsoon region in terms of wet/dry climatic conditions based on precipitation and effective moisture, and of sea surface temperatures. The comparison of the palaeo‐data set to LGM simulations by the Climate Community System Model version 3 (CCSM3) shows fairly good agreement: a dry LGM climate in the western and northern part due to a strengthened winter monsoon and/or strengthened westerly winds and wetter conditions in equatorial areas, due to a stronger summer monsoon. Data–model discrepancies are seen in some areas and are ascribed to the fairly coarse resolution of CCSM3 and/or to uncertainties in the reconstructions. Differences are also observed between the reconstructed and simulated northern boundaries of the Intertropical Convergence Zone (ITCZ). The reconstructions estimate a more southern position over southern India and the Bay of Bengal, whereas CCSM3 simulates a more northern position. In Indochina, the opposite is the case. The palaeo‐data indicate that climatic conditions changed around 20–19 ka BP, with some regions receiving higher precipitation and some experiencing drier conditions, which would imply a distinct shift in summer monsoon intensity. This shift was probably triggered by the late LGM sea‐level rise, which led to changes in atmosphere–ocean interactions in the Indian Ocean. The overall good correspondence between reconstructions and CCSM3 suggests that CCSM3 simulates LGM climate conditions over subtropical and tropical areas fairly well. The few high‐resolution qualitative and quantitative palaeo‐records available for the large Asian monsoon region make reconstructions however still uncertain.     

Ni/S/Cl systematics and the origin of impact‐melt glasses in Martian meteorite Elephant Moraine 79001

Martian meteorite Elephant Moraine A79001 (EET 79001) has received considerable attention for the unusual composition of its shock melt glass, particularly its enrichment in sulfur relative to the host shergottite. It has been hypothesized that Martian regolith was incorporated into the melt or, conversely, that the S‐enrichment stems from preferential melting of sulfide minerals in the host rock during shock. We present results from an electron microprobe study of EET 79001 including robust measurements of major and trace elements in the shock melt glass (S, Cl, Ni, Co, V, and Sc) and minerals in the host rock (Ni, Co, and V). We find that both S and major element abundances can be reconciled with previous hypotheses of regolith incorporation and/or excess sulfide melt. However, trace element characteristics of the shock melt glass, particularly Ni and Cl abundances relative to S, cannot be explained either by the incorporation of regolith or sulfide minerals. We therefore propose an alternative hypothesis whereby, prior to shock melting, portions of EET 79001 experienced acid‐sulfate leaching of the mesostasis, possibly groundmass feldspar, and olivine, producing Al‐sulfates that were later incorporated into the shock melt, which then quenched to glass. Such activity in the Martian near‐surface is supported by observations from the Mars Exploration Rovers and laboratory experiments. Our preimpact alteration model, accompanied by the preferential survival of olivine and excess melting of feldspar during impact, explains the measured trace element abundances better than either the regolith incorporation or excess sulfide melting hypothesis does.     

Metal distribution in sediment cores from São Paulo State Coast, Brazil

Ten sediment core samples with lengths ranging from 35 to 100 cm were collected in the Baixada Santista region and analyzed to determine As, Br, Co, Cr, Cs, Fe, Rb, Sb, Ta, Th, U, Zn and rare earths (Sc, Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) level concentrations using instrumental neutron activation analysis (INAA). The studied region is located in the southeastern coast of São Paulo State and is comprised of a densely urbanized area, the largest industrial complex of the country, with a predominance of petrochemical and fertilizer plants. It is also home to Brazil’s most important and busiest port. The conclusions found that the As, La, Sm, Ne, Ce, Eu, Hf, Ta, Th, and U elements have a high background level in the region and that Fe and Zn were the main indicators of anthropogenic contribution in the sediments.