Relative abundances of sea ice-related abundances in sediment core NBP01-01-JPC24

Micropaleontological and biomarker data from two high-accumulation marine sites from the Coastal and Continental Shelf Zone (CCSZ) off East Antarctica (Adélie Land at w140°E and eastern Prydz Bay at w77°E) are used to reconstruct Holocene changes in sea ice and wind stress at the basin-wide scale. These data demonstrate congruent increase in sea-ice concentration/persistence and wind stress-related sea-surface turbulence in the two regions since 7 cal ka BP, with a particularly strong signal since 4.5 - 3.5 cal ka BP. Comparison of these high latitude records with sea ice and turbulence records from the southern mid-latitudes highlights distinctive climatic evolutions according to the different latitudinal bands. Sea-ice persistence and turbulence increase in East Antarctica CCSZ are opposite to sea-surface warming and sea-ice retreat recorded after 4.5 - 3.5 cal ka BP in the East Atlantic and Indian sector between 55 and 45°S. At the same period, paleodata suggest SST cooling in all major coastal upwelling systems of the southern hemisphere, caused by the northward transport of subpolar surface waters as a response to southern Westerlies reinforcement. We therefore propose, as suggested for the northern hemisphere, that Holocene changes in the latitudinal insolation gradient, primarily forced by obliquity and precession and amplified by sea-ice and glacial-ice expansions in the Antarctic realm, are responsible for the observed contrasted latitudinal patterns of southern latitudes.

Age models and summer sea surface temperature and winter sea ice concentration for the EPILOG-LGM time slice in the Pacific Southern Ocean

Sea surface temperatures and sea-ice extent are the most critical variables to evaluate the Southern Ocean paleoceanographic evolution in relation to the development of the global carbon cycle, atmospheric CO2 variability and ocean-atmosphere circulation. In contrast to the Atlantic and the Indian sectors, the Pacific sector of the Southern Ocean has been insufficiently investigated so far. To cover this gap of information we present diatom-based estimates of summer sea surface temperature (SSST) and winter sea-ice concentration (WSI) from 17 sites in the polar South Pacific to study the Last Glacial Maximum (LGM) at the EPILOG time slice (19,000-23,000 cal. years BP). Applied statistical methods are the Imbrie and Kipp Method (IKM) and the Modern Analog Technique (MAT) to estimate temperature and sea-ice concentration, respectively. Our data display a distinct LGM east-west differentiation in SSST and WSI with steeper latitudinal temperature gradients and a winter sea-ice edge located consistently north of the Pacific-Antarctic Ridge in the Ross sea sector. In the eastern sector of our study area, which is governed by the Amundsen Abyssal Plain, the estimates yield weaker latitudinal SSST gradients together with a variable extended winter sea-ice field. In this sector, sea-ice extent may have reached sporadically the area of the present Subantarctic Front at its maximum LGM expansion. This pattern points to topographic forcing as major controller of the frontal system location and sea-ice extent in the western Pacific sector whereas atmospheric conditions like the Southern Annular Mode and the ENSO affected the oceanographic conditions in the eastern Pacific sector. Although it is difficult to depict the location and the physical nature of frontal systems separating the glacial Southern Ocean water masses into different zones, we found a distinct temperature gradient in latitudes straddled by the modern Southern Subtropical Front. Considering that the glacial temperatures north of this zone are similar to the modern, we suggest that this represents the Glacial Southern Subtropical Front (GSSTF), which delimits the zone of strongest glacial SSST cooling (>4K) to its North. The southern boundary of the zone of maximum cooling is close to the glacial 4°C isotherm. This isotherm, which is in the range of SSST at the modern Antarctic Polar Front (APF), represents a circum-Antarctic feature and marks the northern edge of the glacial Antarctic Circumpolar Current (ACC). We also assume that a glacial front was established at the northern average winter sea ice edge, comparable with the modern Southern Antarctic Circumpolar Current Front (SACCF). During the glacial, this front would be located in the area of the modern APF. The northward deflection of colder than modern surface waters along the South American continent leads to a significant cooling of the glacial Humboldt Current surface waters (4-8K), which affects the temperature regimes as far north as into tropical latitudes. The glacial reduction of ACC temperatures may also result in the significant cooling in the Atlantic and Indian Southern Ocean, thus may enhance thermal differentiation of the Southern Ocean and Antarctic continental cooling. Comparison with temperature and sea ice simulations for the last glacial based on numerical simulations show that the majority of modern models overestimate summer and winter sea ice cover and that there exists few models that reproduce our temperature data rather well.

Effects of seawater pCO2 and temperature on shell growth, shell stability, condition and cellular stress of Western Baltic Sea Mytilus edulis (L.) and Arctica islandica (L.)

Acidification of the World's oceans may directly impact reproduction, performance and shell formation of marine calcifying organisms. In addition, since shell production is costly and stress in general draws on an organism's energy budget, shell growth and stability of bivalves should indirectly be affected by environmental stress. The aim of this study was to investigate whether a combination of warming and acidification leads to increased physiological stress (lipofuscin accumulation and mortality) and affects the performance [shell growth, shell breaking force, condition index (Ci)] of young Mytilus edulis and Arctica islandica from the Baltic Sea. We cultured the bivalves in a fully-crossed 2-factorial experimental setup (seawater (sw) pCO2 levels "low", "medium" and "high" for both species, temperature levels 7.5, 10, 16, 20 and 25 °C for M. edulis and 7.5, 10 and 16 °C for A. islandica) for 13 weeks in summer. Mytilus edulis and A. islandica appeared to tolerate wide ranges of sw temperature and pCO2. Lipofuscin accumulation of M. edulis increased with temperature while the Ci decreased, but shell growth of the mussels only sharply decreased while its mortality increased between 20 and 25 °C. In A. islandica, lipofuscin accumulation increased with temperature, whereas the Ci, shell growth and shell breaking force decreased. The pCO2 treatment had only marginal effects on the measured parameters of both bivalve species. Shell growth of both bivalve species was not impaired by under-saturation of the sea water with respect to aragonite and calcite. Furthermore, independently of water temperatures shell breaking force of both species and shell growth of A. islandica remained unaffected by the applied elevated sw pCO2 for several months. Only at the highest temperature (25 °C), growth arrest of M. edulis was recorded at the high sw pCO2 treatment and the Ci of M. edulis was slightly higher at the medium sw pCO2 treatment than at the low and high sw pCO2 treatments. The only effect of elevated sw pCO2 on A. islandica was an increase in lipofuscin accumulation at the high sw pCO2 treatment compared to the medium sw pCO2 treatment. Our results show that, despite this robustness, growth of both M. edulis and A. islandica can be reduced if sw temperatures remain high for several weeks in summer. As large body size constitutes an escape from crab and sea star predation, this can make bivalves presumably more vulnerable to predation with possible negative consequences on population growth. In M. edulis, but not in A. islandica, this effect is amplified by elevated sw pCO2. We follow that combined effects of elevated sw pCO2 and ocean warming might cause shifts in future Western Baltic Sea community structures and ecosystem services; however, only if predators or other interacting species do not suffer as strong from these stressors.

Water mass evolution of the Greenland Sea since late glacial times

Four sediment cores from the central and northern Greenland Sea basin, a crucial area for the renewal of North Atlantic deep water, were analyzed for planktic foraminiferal fauna, planktic and benthic stable oxygen and carbon iso- topes as well as ice-rafted debris to reconstruct the environ- mental variability in the last 23 kyr. During the Last Glacial Maximum, the Greenland Sea was dominated by cold and sea-ice bearing surface water masses. Meltwater discharges from the surrounding ice sheets affected the area during the deglaciation, influencing the water mass circulation. During the Younger Dryas interval the last major freshwater event occurred in the region. The onset of the Holocene interglacial was marked by an increase in the advection of Atlantic Wa- ter and a rise in sea surface temperatures (SST). Although the thermal maximum was not reached simultaneously across the basin, benthic isotope data indicate that the rate of overturn- ing circulation reached a maximum in the central Greenland Sea around 7ka. After 6-5ka a SST cooling and increas- ing sea-ice cover is noted. Conditions during this so-called "Neoglacial" cooling, however, changed after 3 ka, probably due to enhanced sea-ice expansion, which limited the deep convection. As a result, a well stratified upper water column amplified the warming of the subsurface waters in the central Greenland Sea, which were fed by increased inflow of At- lantic Water from the eastern Nordic Seas. Our data reveal that the Holocene oceanographic conditions in the Green- land Sea did not develop uniformly. These variations were a response to a complex interplay between the Atlantic and Polar water masses, the rate of sea-ice formation and melting and its effect on vertical convection intensity during times of Northern Hemisphere insolation changes.

Abundance and biomass of macrobenthos in the western part of the Black Sea during Mare Nigrum cruise S-RO2

Dataset containing macrobenthos data for samples collected during September 2008 in the North-West Black Sea (between 44°46' - 43°45' N latitude and 30° 11' - 29°35' E longitude). Macrobenthos sampling was done in 4 stations using a 0.14 m**2 Van Veen grab. Washing of the sample through two sieves - 1 mm and 0.25 mm mesh size; the material retained by the two sieves was examined at the binocular microscope; all animals were extracted, using fine tweezers and the species or group of species were identified and counted (in order to determine the density of populations); the larger organisms were measured and weighed (structure and biomass); for smaller organisms, the average wet weights inscribed in standard tables were used to calculate the biomass. Taxonomic identification was done at the GeoEcoMar by A. Teaca and T. Begun using the relevant taxonomic literature ( "Key-book for the identification of the Black Sea and Sea of Azov Fauna, 1968 -1972, Kiev - in Russian, V 1-4; BACESCU, M.C., MÜLLER, G. I., GOMOIU, M.-T., 1971). BACESCU, M.C., MÜLLER, G. I., GOMOIU, M.-T., 1971-Benthic ecological research to Black Sea. Comparative quantitative and qualitative analyse of pontic benthic fauna. Marine Ecology, 4, 1-357 (in Romanian). Key-book for the identification of the Black Sea and Sea of Azov Fauna, 1968 -1972, Kiev, V. 1-4 (in Russian).

Comparison on the durability of different portland cements after five years exposure to sulfate and to sea water attack

Experimental research has been performed to relate specific cement characteristics to deterioration due to sulfate and sea water attack after five year exposure, and to study different test method suitability for sulfate and marine resistance. Sulfate resistance testing have been performed on mortar specimens made with fifteen cement types of statistically diverse chemical composition according to European standard EN 197-1, most of them with sulfate resistant properties according to Spanish regulations. Chemical and mechanical characteristics were studied to determine the variation in properties of selected cements. SO3 content, type and amount of additions, C3A, and C4AF content were used to examine relationships between these characteristics and the results of sulfate resistance. Mortar specimens testing using Na2SO4 as the aggressive medium according to ASTM 1012 (with w/c ratio adapted to prENV 196-X:1995) was performed using each type of cement; identical specimens were also stored in sea water, and in lime saturated water (blank condition), up to five year age. Additionally these cements were tested conforming ASTM 452 and Koch and Steinegger test. Recommended acceptance limits for sulfate resistance of cements concerning to each used test method were evaluated in order to explore their suitability. Relationships between cement characteristics, degradation, expansive products obtained by X-ray diffraction techniques and maximum expansion after applied storage treatments, were correlated at final age, to redefine cement characteristics for sulfate resistant and marine resistant Portland cement

Influence of the Common Agricultural Policy and Heterogeneous Land Quality on Land Rent and Land Allocation. Factor Markets Working Paper No. 38, March 2013

Against the background of the current discussion about the EU’s common agricultural policy (CAP) after 2013, the question of the impact of government support on land prices is crucially important. Validation of the CAP’s success also hinges on a proper assessment of a choice of policy instruments. This study therefore has the objective of investigating on a theoretical basis the effects of different government support measures on land rental prices and land allocation. The different measures under consideration are the price support, area payments and decoupled single farm payments (SFPs) of the CAP. Our approach evaluates the potential impact of each measure based on a Ricardian land rent model with heterogeneous land quality and multiple land uses. We start with a simple model of one output and two inputs, where a Cobb-Douglas production technology is assumed between the two factors of land and non-land inputs. In a second step, an outside option is introduced. This outside option, as opposed to land use of the Ricardian type, is independent of land quality. The results show that area payments and SFPs become fully capitalised into land rents, whereas in a price support scheme the capitalisation depends on per-acreage productivity. Moreover, in a price support scheme and a historical model, the capitalisation is positively influenced by land quality. Both area payments and price supports influence land allocation across different uses compared with no subsidies, where the shift tends to be larger in an area payment scheme than in a price support scheme. By contrast, SFPs do not influence land allocation.

Will improved access to capital dampen the need for more agricultural land? A CGE analysis of agricultural capital markets and world-wide biofuel policies. Factor Markets Working Paper No. 48, May 2013

This paper analyses the consequences of enhanced biofuel production in regions and countries of the world that have announced plans to implement or expand on biofuel policies. The analysis considers biofuel policies implemented as binding blending targets for transportation fuels. The chosen quantitative modelling approach is two-fold: it combines the analysis of biofuel policies in a multi-sectoral economic model (MAGNET) with systematic variation of the functioning of capital and labour markets. This paper adds to existing research by considering biofuel policies in the EU, the US and various other countries with considerable agricultural production and trade, such as Brazil, India and China. Moreover, the application multi-sectoral modelling system with different assumptions on the mobility of factor markets allows for the observation of changes in economic indicators under different conditions of how factor markets work. Systematic variation of factor mobility indicates that the ‘burden’ of global biofuel policies is not equally distributed across different factors within agricultural production. Agricultural land, as the pre-dominant and sector-specific factor, is, regardless of different degrees of inter-sectoral or intra-sectoral factor mobility, the most important factor limiting the expansion of agricultural production. More capital and higher employment in agriculture will ease the pressure on additional land use – but only partly. To expand agricultural production at global scale requires both land and mobile factors adapted to increase total factor productivity in agriculture in the most efficient way.

Polyaromatic hydrocarbons in sediments from the Barents and White Seas

Polycyclic aromatic hydrocarbons (PAHs) are common environmental contaminants which can be derived from anthropogenic sources, such as combustion and discharges from extraction and transport, and natural processes, including leakage and erosion of fossil carbon. Natural PAH sources contribute, along with biological activities and terrestrial run-off, to the organic carbon content in sediments.The Barents Sea region is far from many anthropogenic sources of PAH, but production and trans-shipment of hydrocarbons is increasing. We present data for polycyclic aromatic hydrocarbon (PAH) concentrations in bottom sediments from 510 stations in the Barents and White Seas, and along the northern coast of Norway.

Physical characteristics and bacterial production and respiration at stations sampled during 2008 in the eastern Beaufort Sea

Bacterial carbon demand, an important component of ecosystem dynamics in polar waters and sea ice, is a function of both bacterial production (BP) and respiration (BR). BP has been found to be generally higher in sea ice than underlying waters, but rates of BR and bacterial growth efficiency (BGE) are poorly characterized in sea ice. Using melted ice core incubations, community respiration (CR), BP, and bacterial abundance (BA) were studied in sea ice and at the ice-water interface (IWI) in the Western Canadian Arctic during the spring and summer 2008. CR was converted to BR empirically. BP increased over the season and was on average 22 times higher in sea ice as compared with the IWI. Rates in ice samples were highly variable ranging from 0.2 to 18.3 µg C/l/d. BR was also higher in ice and on average ~10 times higher than BP but was less variable ranging from 2.39 to 22.5 µg C/l/d. Given the high variability in BP and the relatively more stable rates of BR, BP was the main driver of estimated BGE (r**2 = 0.97, P < 0.0001). We conclude that microbial respiration can consume a significant proportion of primary production in sea ice and may play an important role in biogenic CO2 fluxes between the sea ice and atmosphere.

(Table T1) Long-chain alkenones, UK'37 and derived sea surface temperatures of ODP Sites 184-1147 and 184-1148

A reconnaissance study of alkenone stratigraphy for the past 35 m.y. in the northern South China Sea (SCS) using sediments from Sites 1147 and 1148 of Ocean Drilling Program (ODP) Leg 184 has been completed. Alkenones were not detected in sediment samples older than ~31 Ma. However, C37:2 appeared in the sedimentary record between ~8 and 31 Ma and both C37:2 and C37:3 were present between 0 and 8 Ma. These changes in alkenone occurrences may signal a response to global-scale Neogene cooling as well as to monsoon intensification and sea level changes over time as a result of Himalayan uplift and the opening of the SCS. Alternatively, they may be related to an evolutionary record of the development of temperature control on alkenone production in coccolithophores. The Uk'37 index for 0-8 Ma produces sea-surface temperatures (SST) of 19°-26°C, which are in the range of previously determined glacial-interglacial values for the northern SCS. Before the late Pleistocene (~1.2 Ma), the SST range is between 23° and 26°C with less variation. This change in variability may signify the early stage of intensified winter monsoons where cold wind and waters from the north may not yet have had a significant effect on SST or it may be the evolutionary link between the early development of unsaturated alkenones in coccolithophores and modern temperature control of alkenone production. We believe a long-term alkenone record is useful for further understanding of global-scale neogene cooling, the development of the East Asian monsoon system, and the evolutionary development of temperature control on alkenone unsaturation. Our data indicate that a high-resolution Uk'37 record for at least the last ~8 Ma is feasible for the northern SCS.

Response of the salt-freshwater interface in a coastal aquifer to a wave-induced groundwater pulse: field observations and modelling

Field observations on an unconfined coastal aquifer showed that a groundwater pulse, generated by it moderate (significant wave height, H-sig similar to 4.5 m) wave/storm event, induced significant oscillations in the salt-freshwater interface of the order of several metres in the horizontal direction. A dynamic sharp-interface model is developed to quantify the mechanism of these interface oscillations. The model uses the 50% seawater salinity contour as the location of the equivalent sharp-interface. The model was calibrated against the observed groundwater table fluctuations. It predicted reasonably well the interface oscillations with a slight over-prediction of the oscillation magnitude and a steepening of the interface. The neglect of mixing in the salt-freshwater mixing zone by the sharp-interface model is suggested as a possible contributor to the discrepancies between the model predictions and observations. In contrast with the significant wave effects, there was no observable response of the interface to diurnal or semidiurnal tides. (C) 2004 Elsevier Ltd. All rights reserved.

The rising tide of ocean diseases: Unsolved problems and research priorities

New studies have detected a rising number of reports of diseases in marine organisms such as corals, molluscs, turtles, mammals, and echinoderms over the past three decades. Despite the increasing disease load, microbiological, molecular, and theoretical tools for managing disease in the world's oceans are underdeveloped. Review of the new developments in the study of these diseases identifies five major unsolved problems and priorities for future research: (1) detecting origins and reservoirs for marine diseases and tracing the flow of some new pathogens from land to sea; (2) documenting the longevity and host range of infectious stages; (3) evaluating the effect of greater taxonomic diversity of marine relative to terrestrial hosts and pathogens; (4) pinpointing the facilitating role of anthropogenic agents as incubators and conveyors of marine pathogens; (5) adapting epidemiological models to analysis of marine disease.