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Sample records for sea norwegian sea

  1. Field development projects advance in Norwegian Sea

    SciTech Connect

    Vielvoye, R.

    1992-03-30

    This paper reports on the Norwegian Sea, lying between the Norwegian North Sea and the western flank of the Barents Sea, which is set to become Norway's second oil and gas producing province. Oil is scheduled to start to flow near the end of next year when AS Norske Shell places on production 428 million bbl Draugen field in Block 6407/9, about 60 miles off the coast of mid-Norway in the frontier sea area known as Haltenbanken. Two years later, in 1995, Norske Conoco AS will add to the 95,000 b/d from Draugen when it commissions the world's first concrete hull tension leg platform (TLP) in Heidrun field. The TLP is expected to produce 200,000 b/d of oil and move associated gas by pipeline to the Norwegian mainland to feed a worldscale methanol plant planned for construction at Tjeldbergodden. The Norwegian government also has been asked to approve a gas pipeline link between Haltenbanken and the gas export infrastructure in the North Sea.

  2. First drilling in Norwegian sea off Norway yields encouraging results

    SciTech Connect

    Bergsager, E.

    1981-06-08

    Three exploratory wells drilled in the Norwegian Sea penetrated Jurassic sandstones with excellent reservoir qualities, rich source rock, and some evidence of hydrocarbons. Constituting the first wells drilled north of the 62nd parallel off Norway, they produced encouraging evidence of prospective structures. The Norwegian continental shelf north of the North Sea contains areas of thick sedimentary basins having an areal extent 8-9 times that of the Norwegian North Sea.

  3. Permian of Norwegian-Greenland sea margins: future exploration target

    SciTech Connect

    Surlyk, F.; Hurst, J.M.; Piasecki, S.; Rolle, F.; Stemmerik, L.; Thomsen, E.; Wrang, P.

    1984-09-01

    Oil and gas exploration in the northern North Sea and the southern Norwegian shelf has mainy been concentrated on Jurassic and younger reservoirs with Late Jurassic black shale source rocks. New onshore investigations in Jameson Land, central East Greenland, suggest that the Permian of the Norwegian-Greenland Sea margins contains relatively thick sequences of potential oil source rocks interbedded with carbonate reefs. The East Greenland, Upper Permian marine basin is exposed over a length of 400 km (250 mi) from Jameson Land in the south to Wollaston Forland in the north, parallel with the continental margin. The Upper Permian black shale is relatively thick, widely distributed, has a high organic carbon content, and a favorable kerogen type. Consequently, the possibilities for a Permian play in the northern part of the Norwegian shelf and along parts of the Norwegian-Greenland Sea margins are worth evaluating.

  4. Deepwater cementing in the Norwegian Sea: A case study

    SciTech Connect

    Helgesen, J.T.; Harestad, K.; Sorgaard, E.

    1999-04-01

    During Norway`s 15th licensing round in 1996, five deepwater areas were opened for exploration drilling. All blocks are situated outside the continental shelf in the Norwegian Sea, west of mid-Norway. The seabed and location conditions were studied by the Norwegian Deepwater Project, a joint venture of the operator companies who were awarded blocks in these new unexplored areas. Results of the study revealed that the weather and sea conditions in these remote areas would be among the toughest in the world. Strong return currents from the Arctic Ocean bring undercooled water to these locations, lowering the seabed temperature to as low as {minus}2 C. Because all the blocks are situated outside the Norwegian continental shelf, the water depth is in the range of 2,600--5,000 ft (800--1,600 m). Typical deepwater conditions are present in most of the deepwater locations in the Norwegian Sea. The conditions that posed additional challenges to the drilling operation were poorly consolidated sediments, shallow water flow zones, hydrate destabilization and ooze sediments. The paper describes sediment consolidation, shallow water flow, hydrates, development of deepwater cement slurries, a field case, and future cementing operations in Norway.

  5. Carbon export by small particles in the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Dall'Olmo, Giorgio; Mork, Kjell Arne

    2014-04-01

    Despite its fundamental role in controlling the Earth's climate, present estimates of global organic carbon export to the deep sea are affected by relatively large uncertainties. These uncertainties are due to lack of observations as well as disagreement among methods and assumptions used to estimate carbon export. Complementary observations are thus needed to reduce these uncertainties. Here we show that optical backscattering measured by Bio-Argo floats can detect a seasonal carbon export flux in the Norwegian Sea. This export was most likely due to small particles (i.e., 0.2-20 ?m), was comparable to published export values, and contributed to long-term carbon sequestration. Our findings highlight the importance of small particles and of physical mixing in the biological carbon pump and support the use of autonomous platforms as tools to improve our mechanistic understanding of the ocean carbon cycle.

  6. Norwegian petroleum resources with focus on challenges and opportunities in the Barents Sea

    SciTech Connect

    Aamodt, F.R.

    1995-12-31

    The Norwegian Continental Shelf can be subdivided into 3 different petroleum provinces: (1) the North Sea, (2) the Norwegian Sea including the Jan Mayen ridge, and (3) the Barents Sea including the islands of Svalbard. The majority of the fields and discoveries and most of the resources are located in the mature North Sea Basin. Significant resources are however also discovered in the Norwegian Sea and the Barents Sea. 39 fields are in production or decided to be developed while 3 fields are closed down. Approximately 70% of the discovered resources are located in these fields, of which some are gigantic in size (Statfjord, Ekofisk, Gullfaks, Oseberg, Troll and Snorre). Most of the remaining discoveries (134) are smaller in size and approximately 2/3 of the resources are gas. According to a recent study carried out by the Norwegian Petroleum Directorate the expected undiscovered Norwegian Petroleum Resources are assessed to be on the order of 3,5 billion Sm{sup 3} o.e. with a level of uncertainty ranging from 2 to 6 billion Sm{sup 3} o.e. 40% of the undiscovered petroleum resources are expected to be found as oil. These are the perspectives of the Norwegian Petroleum Resources. The resources of the Barents Sea is included in this perspective. The significance of the Barents Sea resources is not particularly important in the short-medium term perspective, but will be important in the longer perspective.

  7. Structural evolution and petroleum potential of the Norwegian Barents Sea

    SciTech Connect

    Nilsen, K.T.

    1995-08-01

    The tectonic history of the Norwegian Barents Sea has provided potential hydrocarbon traps in clastic reservoirs associated with rotated fault blocks, compressional anticlines and salt domes. Significant stratigraphic potential also resides in Paleozoic carbonates. Drilling in the Hammerfest Basin has yielded large gas discoveries in rotated fault blocks, but other trapping concepts remain relatively untested. The undrilled arm north of 74{degrees} 30 minutes N, currently being mapped by the Norwegian Petroleum Directorate using exclusive seismic and geological data from shallow boreholes, represents a significant area for future exploration. Prospectivity is critically dependent on the scaling of traps following Neogene uplift of large areas of the Barents platform. The area is dominated by structural trends inherited from the Caledonian and older orogens. Carboniferous rifting established a system of half grabens and intervening highs, followed by late Permian faulting in the west which initiated regional subsidence continuing into the early Jurassic. Fault reactivation in early Triassic times triggered salt diapirism and provided structural control for the formation of Triassic shelf margins. During the late Jurassic-early Cretaceous western basins underwent tectonic subsidence, while the northeastern platform arm was subject to gentle compression. In the late Cretaceous salt was reactivated in the Nordkapp Basin and compressional structures developed west of the Loppa High. Further subsidence of the western basins was promoted by late Mesozoic and early Tertiary transtensional movements along the North Atlantic rift system. Subsequent regional compression in these basins, and basin inversion east of the Loppa High, are of post-Eocene age.

  8. Inter-annual to decadal sea level variability along the Norwegian coast and in the Siberian Seas; a link with the Eastern North Atlantic

    NASA Astrophysics Data System (ADS)

    Calafat, F. M.; Chambers, D. P.

    2012-12-01

    Inter-annual to decadal sea level variations from tide gauge records along the Norwegian coast and in the Siberian Seas are examined for the period 1950 to present. A combination of observations and theory is used to explore the physical mechanisms responsible for the observed sea level variability. Tide gauge records are first grouped into 6 geographical regions: the Norwegian Coast, the Barents Sea, the Kara Sea, the Laptev Sea, the East Siberian Sea, and the Chukchi Sea. Then an average of sea level at tide gauges is computed for each region. All regions exhibit large decadal sea level variations (up to 20 cm). Sea level corrected for the inverse barometer effect is significantly correlated with the Arctic Oscillation index in all regions except in the East Siberian and Chukchi Seas. There is a coherent sea level signal that affects a region extending from Southwest Norway to the Kara Sea. Previous studies have found that sea level variability at the Norwegian coast is related to variations in the Norwegian Atlantic Current (NwAC), which are mainly driven by changes in the wind forcing over the region. Here we show that, apart from the contribution of the NwAC and the local wind, there is an additional contribution to the sea level variability at the Norwegian coast resulting from the poleward propagation of wind-driven sea level variations along the continental slope of the Northeast Atlantic. The fact that sea level variability in both the Barents and the Kara Seas is highly coherent with that in the Norwegian coast suggests propagation of sea level variations further north into these regions. Eastward of the Kara Sea, where the continental shelf is shallower, sea level variations are much larger than in the other regions and they are highly correlated (~0.75) with the local longshore wind.he average of sea level at 8 tide gauge stations on the Norwegian coast (black line) and a reconstruction of sea level (blue line) using a combination of the tide gauge at Newlyn (on the eastern boundary of the North Atlantic) and the longshore wind over the Faroe-Shetland channel and the Norwegian continental shelf. The grey shaded area represents the uncertainty of the time series. A 2-year running mean has been applied to both time series.

  9. Ecosystem structure and resilience—A comparison between the Norwegian and the Barents Sea

    NASA Astrophysics Data System (ADS)

    Yaragina, Natalia A.; Dolgov, Andrey V.

    2009-10-01

    Abundance and biomass of the most important fish species inhabited the Barents and Norwegian Sea ecosystems have shown considerable fluctuations over the last decades. These fluctuations connected with fishing pressure resulted in the trophic structure alterations of the ecosystems. Resilience and other theoretical concepts (top-down, wasp-waste and bottom-up control, trophic cascades) were viewed to examine different response of the Norwegian and Barents Sea ecosystems on disturbing forces. Differences in the trophic structure and functioning of Barents and Norwegian Sea ecosystems as well as factors that might influence the resilience of the marine ecosystems, including climatic fluctuation, variations in prey and predator species abundance, alterations in their regular migrations, and fishing exploitation were also considered. The trophic chain lengths in the deep Norwegian Sea are shorter, and energy transfer occurs mainly through the pelagic fish/invertebrates communities. The shallow Barents Sea is characterized by longer trophic chains, providing more energy flow into their benthic assemblages. The trophic mechanisms observed in the Norwegian Sea food webs dominated by the top-down control, i.e. the past removal of Norwegian Spring spawning followed by zooplankton development and intrusion of blue whiting and mackerel into the area. The wasp-waist response is shown to be the most pronounced effect in the Barents Sea, related to the position of capelin in the ecosystem; large fluctuations in the capelin abundance have been strengthened by intensive fishery. Closer links between ecological and fisheries sciences are needed to elaborate and test various food webs and multispecies models available.

  10. Scalar winds from SSM/I in the Norwegian and Greenland seas during Norcsex

    NASA Technical Reports Server (NTRS)

    Gloersen, Per; Hubanks, Paul

    1989-01-01

    Data acquired with the Defense Meteorological Satellite Program (DMSP) special sensor microwave imager (SSM/I) during the Norwegian Coastal Sea Experiment (Norcsex) in March 1988 have been utilized to estimate scalar winds in the Norwegian and Greenland Seas. The algorithm for calculating these winds was first developed for the Nimbus-7 scanning multichannel microwave radiometer (SMMR) in order to investigate scalar winds during the Polar Lows Experiment in February 1984. The coefficients in this algorithm have been tuned to accommodate differences in the SSM/I and SMMR instruments.

  11. Subsea template, pipeline anchor Troll-Oseberg gas-injection scheme in Norwegian North Sea

    SciTech Connect

    Weibye, B.S.

    1988-01-18

    The author discusses the subsea, gas production template and the 30-mile pipeline that are key elements in supplying as from the Troll field for injection into Oseberg field in the Norwegian North Sea by 1991. The author discusses the design basis and philosophies as well as the production system, template installation and control pods.

  12. Experience of cathodic protection, fabrication and installation of anodes for deep water pipelines in the North Sea and the Norwegian Sea

    SciTech Connect

    Eliassen, S.; Pettersen, N.H.

    1996-08-01

    Statoil is the major operator of the oil and gas pipelines in the North Sea and the Norwegian Sea. Different coating systems have been used for external corrosion protection of the pipelines. The paper presents the company`s experience regarding cathodic protection design and fabrication and installation of anodes for deep water pipelines.

  13. Relation between liquid hydrocarbon reserves and geothermal gradients - Norwegian North Sea

    SciTech Connect

    Baird, R.A. )

    1991-03-01

    Comparison of average geothermal gradients and initial liquid hydrocarbon reserves for 28 Norwegian North Sea fields indicates that gradients in the largest North Sea oil fields cluster around 2.1F/100 feet. No reserves are found where gradients are lower than 1.8F/100 feet or higher than 2.3F/100 feet. At 6.89 billion barrels, reserves for 14 fields falling between 2.05 and 2.15/100 feet total over four times the reserves for all other fields put together. Reserves for seven fields at gradients lower than 2.05F/100 feet and for seven higher than 2.15F/100 feet total 594 and 991 million barrels, respectively. The conclusion is that 2.1F/100 feet is the optimum gradient for generation of liquid hydrocarbons in the Norwegian North Sea, given the depth, kerogen type, and source rock potential of the Kimmeridge Clay, the primary source rock there. Gradients lower than this have not stimulated maximum generation from the source rock. At higher gradients, increasing gas production from source rocks and thermal cracking of previously generated liquid hydrocarbons to gas are effective in limiting liquid hydrocarbon reserves. The 2.1F/100 feet gradient should be a useful pathfinder in the search for new oil reserves in the Norwegian North Sea. Determination of the optimum gradient should be a useful pathfinder in other regions as well.

  14. Bioaccumulation of 137Cs in pelagic food webs in the Norwegian and Barents Seas.

    PubMed

    Heldal, Hilde Elise; Føyn, Lars; Varskog, Per

    2003-01-01

    Knowledge and documentation of the levels of radioactive contamination in fish stocks important to Norwegian fisheries is of major importance to Norwegian consumers and fish export industry. In the present study, the bioaccumulation of caesium-137 ((137)Cs) has been investigated in marine food webs in the Barents and Norwegian Seas. The contents of (137)Cs in the different organisms were generally low (<1 Bq kg(-1) wet weight), but a marked bioaccumulation was apparent: The concentration of (137)Cs was about 10-fold higher in the harbour porpoise Phocoena phocoena, representing the upper level of the food web, than in the amphipod Themisto sp., representing the lower level of the food web. The Concentration Factors (CF=Bq kg(-1) wet weight/Bq l(-1) seawater) increased from 10+/-3 for a mixed sample of krill and amphipods to 165+/-5 for harbour porpoises. PMID:12527234

  15. Chemostratigraphy of Upper Cretaceous chalk sequences in Norwegian-Danish basin and North Sea Central Trough

    SciTech Connect

    Joergensen, N.O.

    1987-05-01

    Geochemical studies of subsurface sections and outcrops in the Upper Cretaceous chalk sequences from the Norwegian-Danish basin and the North Sea Central Trough have resulted in a detailed chemostratigraphy for these strata. The most applicable chemostratigraphic markers are based on the distribution of strontium, magnesium, manganese, the /sup 13/C//sup 12/C ratio, and the variations in the carbonate contents. It is demonstrated that the chemostratigraphic approach is valid at two levels: (1) a superior chemostratigraphy in which deep-sea cores from the Atlantic Ocean and sections from western Europe are correlated on the basis of significant geochemical anomalies and long-term variations most likely induced by oceanic geochemical cycles and sea level fluctuations; (2) a subordinate but detailed intrabasinal chemostratigraphic correlation which primarily reflects the physicochemical conditions in the depositional environment. The Upper Cretaceous chemostratigraphy established in the Danish area allows a detailed correlation between relatively continuous chalk sequences in the Norwegian-Danish basin and the rather condensed and hiati-influenced sections in the oil fields of the North Sea. The results emphasize the applicability of chemostratigraphy in the subsurface exploration for hydrocarbon reservoirs in chalk.

  16. A study of oceanic surface heat fluxes in the Greenland, Norwegian, and Barents Seas

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Cavalieri, Donald J.

    1989-01-01

    This study examines oceanic surface heat fluxes in the Norwegian, Greenland, and Barents seas using the gridded Navy Fleet Numerical Oceanography Central surface analysis and the First GARP Global Experiment (FGGE) IIc cloudiness data bases. Monthly and annual means of net and turbulent heat fluxes are computed for the FGGE year 1979. The FGGE IIb data base consisting of individual observations provides particularly good data coverage in this region for a comparison with the gridded Navy winds and air temperatures. The standard errors of estimate between the Navy and FGGE IIb winds and air temperatures are 3.6 m/s and 2.5 C, respectively. The computations for the latent and sensible heat fluxes are based on bulk formulas with the same constant heat exchange coefficient of 0.0015. The results show extremely strong wintertime heat fluxes in the northern Greenland Sea and especially in the Barents Sea in contrast to previous studies.

  17. The Norwegian Danish Basin: A key to understanding the Cenozoic in the eastern North Sea

    NASA Astrophysics Data System (ADS)

    Rasmussen, Thomas L.; Clausen, Ole R.; Andresen, Katrine J.; Goledowski, Bartosz

    2015-04-01

    The Danish part of Norwegian-Danish Basin, which constitutes the eastern part of the North Sea Basin, has been the key area for sequence stratigraphic subdivision and analysis of the Cenozoic succession since the mid 1990's. Widespread 3D seismic data, in the central parts of the North Sea Basin, as well as more scattered 3D seismic data in the Danish part of the Norwegian-Danish Basin, have given a more detailed understanding of the sequences and indicate that climate is tenable for the origin of Cenozoic sequence boundaries. The previous sequence stratigraphic interpretations have been an integrated part of an ongoing debate concerning vertical movements of the Fennoscandian shield versus the impact of climate and erosion. A newly accessed coherent regional 2D and reprocessed 3D seismic data set, in the Norwegian part of the Norwegian-Danish Basin, constitute the database for a new sequence stratigraphic analysis of the entire area. The objective of the new study is to test previous subdivisions and introduce a coherent 3D sequence stratigraphic analysis and depositional model for the entire Norwegian-Danish Basin. This analysis is necessary to get out of the stalemate with the uplift discussion. The study shows that the original subdivision by Michelsen et al. (1995, 1998) stands. However, revision of few a sequence boundaries may have to be adjusted due to new biostratigraphic information published. Furthermore, high-angle clinoforms and geomorphological transport complexes observed in the Danish North Sea Basin can be traced into the Norwegian sector. This together with the recognition of several other high-angle clinoform complexes, and their associated seismic facies distribution maps and thickness-maps, enhances the level of detail and constrains the previous published paleogeographic reconstructions of the Cenozoic. The geometry of the Cenozoic infill, in the Norwegian part of the Norwegian-Danish Basin, is here interpreted to be controlled by relative sea-level changes and sourced from the Scandinavian hinterland. 3D-Wheeler diagrams have been used for recognizing spatial elements with periods of deposition and non-deposition. Overall, this study thus contributes significantly to a better understanding of the Cenozoic evolution, the position of potential reservoirs and the debate of climate versus tectonics. References: Michelsen, O., M. Danielsen, C. Heilmann-Clausen, H. Jordt, G. V. Laursen and E. Thomsen, Eds. (1995). Occurrence of major sequence stratigraphic boundaries in relation to basin development in Cenozoic deposits of the southeastern North Sea. Sequence Stratigraphy: Advances and Applications for Exploration and Producing in North West Europe vol 5. Amsterdam, Elsevier. Michelsen, O., E. Thomsen, M. Danielsen, C. Heilmann-Clausen, H. Jordt and G. V. Laursen (1998). Cenozoic sequence stratigraphy in the eastern North Sea. Mesozoic-Cenozoic Sequence Stratigraphy of Western European Basins. P. C. de Graciansky, T. Jacquin and P. R. Vail, Society of Economic Palaeontolgists and Mineralogists Special Publication 60. 60: 91-118.

  18. High Acidification Rate of Norwegian Sea Revealed by Boron Isotopes in the Deep-Sea Coral Madrepora Oculata

    NASA Astrophysics Data System (ADS)

    Gonzalez, C.; Douville, E.; Hall-Spencer, J.; Montagna, P.; Louvat, P.; Gaillardet, J.; Frank, N.; Bordier, L.; Juillet-Leclerc, A.

    2012-12-01

    Ocean acidification and global warming due to the increase of anthropogenic CO2 are major threats for marine calcifying organisms, such as deep-sea corals, particularly in high-latitude regions. In order to evaluate the current anthropogenic perturbation and to properly assess the impacts and responses of calcifiers to previous changes in pH it is critical to investigate past changes of the seawater carbonate system. Unfortunately, current instrumental records of oceanic pH are limited, covering only a few decades. Scleractinian coral skeletons record chemical parameters of the seawater in which they grow. However, pH variability over multidecadal timescales remains largely unknown in intermediate and deep seawater masses. Here we present a study that highlights the potential of deep-sea-corals to overcome the lack of long-term pH records and that emphasizes a rapid acidification of high latitude subsurface waters of Norwegian Sea during the past decades. We have reconstructed seawater pH and temperature from a well dated deep-sea coral specimen Madrepora oculata collected alive from Rst reef in Norwegian Sea (67N, 9E, 340 m depth). This large branching framework forming coral species grew its skeleton over more than four decades determined using AMS 14C and 210Pb dating (Sabatier et al. 2012). B-isotopes and Li/Mg ratios yield an acidification rate of about -0.00300.0008 pH-unit.year-1 and a warming of 0.3C during the past four decades (1967-2007). Overall our reconstruction technique agrees well with previous pH calculations (Hnisch et al., 2007 vs. Trotter et al., 2011 and McCulloch et al., 2012, i.e. the iterative method), but additional corrections are here applied using stable isotope correlations (O, C, B) to properly address kinetic fractionation of boron isotopes used for pH reconstruction. The resulting pH curve strongly anti-correlates with the annual NAO index, which further strengthens our evidence for the ocean acidification rate calculated here. If the rate of atmospheric CO2 emission is not reduced, the Rst reef will become undersaturated in aragonite by the end of century. Sabatier P. et al., 2012. Biogeosciences, 9, 1253-1265. Hnisch B. et al., 2007. Geochim. Cosmochim. Acta 71, 1636-1641. Trotter J. et al., 2011. Earth and Planetary Science Letters 303 (2011) 163-73. McCulloch M. et al., 2012. Geochim. Cosmochim. Acta 82, 154-162

  19. An overview of the ecosystems of the Barents and Norwegian Seas and their response to climate variability

    NASA Astrophysics Data System (ADS)

    Loeng, Harald; Drinkwater, Ken

    2007-11-01

    The principal features of the marine ecosystems in the Barents and Norwegian Seas and some of their responses to climate variations are described. The physical oceanography is dominated by the influx of warm, high-salinity Atlantic Waters from the south and cold, low-salinity waters from the Arctic. Seasonal ice forms in the Barents Sea with maximum coverage typically in March-April. The total mean annual primary production rates are similar in the Barents and Norwegian Seas (80-90 g C m -2), although in the Barents, the production is higher in the Atlantic than in the ice covered Arctic Waters. The zooplankton is dominated by Calanus species, C. finmarchicus in the Atlantic Waters of the Norwegian and Barents Seas, and C. glacialis in the Arctic Waters of the Barents Sea. The fish species in the Norwegian Sea are mostly pelagics such as herring ( Clupea harengus) and blue whiting ( Micromesistius poutassou), while in the Barents Sea there are both pelagics (capelin ( Mallotus villosus Mülle r), herring, and polar cod ( Boreogadus saida Lepechin)) and demersals (cod ( Gadus morhua L.) and haddock ( Melanogrammus aeglefinus)). The latter two species spawn in the Norwegian Sea along the slope edge (haddock) or along the coast (cod) and drift into the Barents Sea. Marine mammals and seabirds, although comprising only a relatively small percentage of the biomass and production in the region, play an important role as consumers of zooplankton and small fish. While top-down control by predators certainly is significant within the two regions, there is also ample evidence of bottom-up control. Climate variability influences the distribution of several fish species, such as cod, herring and blue whiting, with northward shifts during extended warm periods and southward movements during cool periods. Climate-driven increases in primary and secondary production also lead to increased fish production through higher abundance and improved growth rates.

  20. Neogene Contourite Drift Development in the Norwegian - Greenland Sea Area; Paleoceanographic Implications

    NASA Astrophysics Data System (ADS)

    Sverre Laberg, Jan; Rebesco, Michele; Lucchi, Renata G.; Stoker, Martyn S.

    2015-04-01

    For the evolution of the Cenozoic high northern latitude paleo-climate, the development of the North Atlantic - Arctic Ocean interactions including its southern (Faeroe - Shetland channel) and northern (Fram Strait) gateways were vital. In this paper we review the timing of inflow of paleo-Atlantic water into the Norwegian - Greenland Sea and the Arctic Ocean using the development of ocean current controlled contourite drift deposition as a proxy. In the early Miocene, drift growth accelerated in the Rockall Trough and in the Faroe-Shetland Channel interpreted to be related to the opening of the Faeroe - Shetland channel and establish a deep-water passage across the Greenland - Shetland Ridge. To the north, offshore Norway, growth of the Lofoten Drift has been estimated from mid-Miocene although age control is sparse in this area. No drift development has been reported from the SW Barents Sea continental slope while offshore the NW part of the Barents Sea slope, drift growth seems to have come in later, at ~1.3 Ma. North of the Fram Strait gateway, drift growth has been inferred from at least mid-Miocene (~11 Ma). Studies from the central Arctic Ocean shows ventilated surface water conditions from ~17.5 Ma ascribed to the opening of the Fram Strait which was a narrow oceanic corridor during early Miocene (20 - 15 Ma) and where the onset of sea floor spreading and the establishment of a deep-water corridor has been suggested to start from late Miocene (~10 Ma). Other, more recent studies have, however, reported evidence for the development of an initial deep-water gateway through the Fram Strait from around 17 Ma. To summarize: - A circulation system similar to the present was probably established in the southern Norwegian - Greenland Sea before the Fram Strait became a deep-water gateway and before the establishments of the major ice sheets in this area (the first occurred in SE Greenland from ~7 Ma). - Uncertainties still relates to the timing of the development of ocean circulation in the northern Norwegian - Greenland Sea including the Fram Strait gateway where drift onset has been estimated to at least 11 Ma. - The onset of drift growth at 1.3 Ma slightly south of the Fram Strait occurred after the onset of deep-water circulation through the Fram Strait and it is inferred to be related to the glacial expansion recorded in the area.

  1. Cenozoic Contourite Drift Development in the Norwegian - Greenland Sea Area: Paleoceanographic Implications

    NASA Astrophysics Data System (ADS)

    Laberg, J. S.; Rebesco, M.; Lucchi, R. G.; Stoker, M. S.

    2014-12-01

    For the evolution of the Cenozoic high northern latitude paleo-climate, the development of the North Atlantic - Arctic Ocean interactions including its southern (Faeroe - Shetland channel) and northern (Fram Strait) gateways were vital. In this paper we review the timing of inflow of paleo-Atlantic water into the Norwegian - Greenland Sea and the Arctic Ocean using the development of ocean current controlled contourite drift deposition as a proxy. In the early Miocene, drift growth accelerated in the Rockall Trough and in the Faroe-Shetland Channel interpreted to be related to the opening of the Faeroe - Shetland channel and establish a deep-water passage across the Greenland - Shetland Ridge. To the north, offshore Norway, growth of the Lofoten Drift has been estimated from mid-Miocene although age control is sparse in this area. No drift development has been reported from the SW Barents Sea continental slope while offshore the NW part of the Barents Sea slope, drift growth seems to have come in later, at ~1.3 Ma. North of the Fram Strait gateway, drift growth has been inferred from at least mid-Miocene (~11 Ma). Studies from the central Arctic Ocean shows ventilated surface water conditions from ~17.5 Ma ascribed to the opening of the Fram Strait which was a narrow oceanic corridor during early Miocene (20 - 15 Ma) and where the onset of sea floor spreading and the establishment of a deep-water corridor has been suggested to start from late Miocene (~10 Ma). Other, more recent studies have, however, reported evidence for the development of an initial deep-water gateway through the Fram Strait from around 17 Ma. To summarize: - A circulation system similar to the present was probably established in the southern Norwegian - Greenland Sea before the Fram Strait became a deep-water gateway and before the establishments of the major ice sheets in this area (the first occurred in SE Greenland from ~7 Ma). - Uncertainties still relates to the timing of the development of ocean circulation in the northern Norwegian - Greenland Sea including the Fram Strait gateway where drift onset has been estimated to at least 11 Ma. - The onset of drift growth at 1.3 Ma slightly south of the Fram Strait occurred after the onset of deep-water circulation through the Fram Strait and it is inferred to be related to the glacial expansion recorded in the area.

  2. Selective erosion by gravity flows in the deep-sea Lofoten Basin, Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Sverre Laberg, Jan; Forwick, Matthias; Johannessen, Hilde B.; Ivanov, Mikhail; Kenyon, Neil H.; Vorren, Tore O.

    2010-05-01

    Deposits from gravity flows form a substantial part of the Lofoten Basin stratigraphy, a deep-water basin offshore Norway. This includes glacigenic debris flows from the shelf edge/upper slope, sandy turbidites from canyon - channel systems and debris flow deposits from submarine landslides. Little is, however, known about the properties of the gravity flows and their interaction with the sea floor sediments. We present newly acquired deep-towed side-scan sonar data co-registered with sub-bottom profiles showing small and large-scale irregularities of the sea floor in two areas relatively recently affected by gravity flows. The first area is located at about 2700 m water depth and is part of the distal Andya Slide. Here, three several km wide and about 25 m thick lensoid and acoustically transparent deposits with a slightly irregular relief are inferred to represent debris flow deposits from submarine landslides originating from the nearby continental slope. The seafloor both below the debris flows and between and not affected by the debris flows is irregular due to closed seafloor depressions. They occur randomly and with a variety of forms up to 1 km across, 500 m wide and some meters deep. The second area is the Lofoten Basin Channel near its termination at about 3200 m water depth, beyond which laterally extensive sheets of normal graded sand interbedded with thinner mud layers occur. Sea floor depressions appear in several morphological forms on the channel flanks. The largest is more than 1 km long, up to 250 m wide, some meters deep has its longest axis parallel to the flow direction. It becomes less distinct in the down-flow direction. Other features in this area include densely spaced longitudinal features. In both areas the irregular sea floor morphology is inferred to be flute marks (or scours) formed by erosive gravity flows. Erosion of channel flanks by turbidity currents is well known from other studies but is not commonly described from the most distal channel settings as shown here. In the deepest part of the Lofoten Basin at least some of the flows overtopped and were erosive to the termination of the channel implying that the transition from erosion to deposition forming the sheets of sand occurred over a very short distance. The occurrence of flute marks in the area of the distal Andya Slide indicates passage of spatially extensive and unconfined turbidity currents possibly associated with the slide event. The flows were accelerating or steadily flowing resulting in erosion and little or no deposition in part of the eastern Lofoten Basin. Acknowledgement This work is a contribution to the UNESCO program Training Trough Research and the Democen project (http://www.ig.uit.no/Democen/). We acknowledge the Research Council of Norway and Statoil for financial support. The Captain and crew of the Russian research vessel Professor Logachev provided essential support for the acquisition of data.

  3. Distribution and diversity patterns of asellote isopods (Crustacea) in the deep Norwegian and Greenland Seas

    NASA Astrophysics Data System (ADS)

    Svavarsson, Jrundur; Brattegard, Torleiv; Strmberg, Jarl-Ove

    Distribution and diversity patterns of asellote isopods (Crustacea) of the deep Norwegian and Greenland Seas are described. The asellotes show the same pattern of rapid faunal change across the upper continental slope as commonly described elsewhere. Here the rate of species replacement is maximum at depths of 800-1000m, but decreases towards greater depths. The distribution of the asellotes shows some correlations to the distribution of sediment types. Species diversity is maximum at 800m and decreases with depth. The species diversity pattern is related here to heterogeneity of the sediments and different species immigration rates into shallow and deep Arctic waters.

  4. Simulations of the mesoscale circulation of the Greenland-Iceland-Norwegian Seas

    NASA Technical Reports Server (NTRS)

    Heburn, George W.; Johnson, Clifford D.

    1995-01-01

    The Greenland, Iceland, and Norwegian Seas provide the only link between the North Atlantic and the Arctic Oceans. This is a very dynamic region, rich in mesoscale variability. A two-layer, hydrodynamic version of the Navy layered ocean model is used to simulate the mesoscale frontal features and associated current systems. The model is wind-driven using monthly mean wind stresses and inflow/outflow mass flux from the Arctic and North Atlantic Oceans. The current transports from the model results compare favorably with transport measurements from a number of observational experiments.

  5. Overseas trip report, CV 990 underflight mission. [Norwegian Sea, Greenland ice sheet, and Alaska

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Crawford, J.; Hardis, L.

    1980-01-01

    The scanning microwave radiometer-7 simulator, the ocean temperature scanner, and an imaging scatterometer/altimeter operating at 14 GHz were carried onboard the NASA CV-990 over open oceans, sea ice, and continental ice sheets to gather surface truth information. Data flights were conducted over the Norwegian Sea to map the ocean polar front south and west of Bear Island and to transect several Nimbus-7 footprints in a rectangular pattern parallel to the northern shoreline of Norway. Additional flights were conducted to obtain correlative data on the cryosphere parameters and characteristics of the Greenland ice sheet, and study the frozen lakes near Barrow. The weather conditions and flight path way points for each of the nineteen flights are presented in tables and maps.

  6. Changes in significant and maximum wave heights in the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Feng, Xiangbo; Tsimplis, M. N.; Yelland, M. J.; Quartly, G. D.

    2014-02-01

    This paper analyses 10 years of in-situ measurements of significant wave height (Hs) and maximum wave height (Hmax) from the ocean weather ship Polarfront in the Norwegian Sea. The 30-minute Ship-Borne Wave Recorder measurements of Hmax and Hs are shown to be consistent with theoretical wave distributions. The linear regression between Hmax and Hs has a slope of 1.53. Neither Hs nor Hmax show a significant trend in the period 2000-2009. These data are combined with earlier observations. The long-term trend over the period 1980-2009 in annual Hs is 2.72 ± 0.88 cm/year. Mean Hs and Hmax are both correlated with the North Atlantic Oscillation (NAO) index during winter. The correlation with the NAO index is highest for the more frequently encountered (75th percentile) wave heights. The wave field variability associated with the NAO index is reconstructed using a 500-year NAO index record. Hs and Hmax are found to vary by up to 1.42 m and 3.10 m respectively over the 500-year period. Trends in all 30-year segments of the reconstructed wave field are lower than the trend in the observations during 1980-2009. The NAO index does not change significantly in 21st century projections from CMIP5 climate models under scenario RCP85, and thus no NAO-related changes are expected in the mean and extreme wave fields of the Norwegian Sea.

  7. Mid-1980s distribution of tritium, 3He, 14C and 39Ar in the Greenland/Norwegian seas and the Nansen basin of the Arctic ocean

    SciTech Connect

    Schlosser, P.; Bonisch, G.; Kromer, B.; Loosli, H.H.; Buehler, R.

    1995-12-31

    The distributions of tritium/3He, 14C and 39Ar observed in the period between 1985 and 1987 in the Greenland/Norwegian Seas and the Nansen Basin of the Arctic Ocean are presented. The data are used to outline aspects of the large-scale circulation and the exchange of deep water between the Greenland/Norwegian Seas and the Nansen Basin. Additionally, semi-quantitative estimates of mean ages of the main water masses found in these regions are obtained. Apparent tritium/3He ages of the upper waters (depth <500m) vary from close to zero in the Norwegian Current to about 15 years at the lower boundary of the Arctic halocline. The deep waters (>1,500m depth) of the Greenland/ Norwegian Seas show apparent tritium/3He ages between about 17 years in the Greenland Sea and 30 years in the Norwegian Sea.

  8. CO2 Storage Atlas Norwegian Sea - a case study from the Froan Basin

    NASA Astrophysics Data System (ADS)

    Sande Rød, Rita; Pham, Van T. H.

    2014-05-01

    The CO2 storage atlas of the Norwegian Sea has been prepared by the Norwegian Petroleum Directorate at the request of the Ministry of Petroleum and Energy. The main objectives have been to identify the safe and effective areas for long-term storage of CO2 and to avoid possible negative interference with ongoing and future petroleum activity. We have built on the knowledge we have from the petroleum industry and from the two ongoing CO2 storage projects, Sleipner and Snøhvit, on the Norwegian Continental Shelf. Five aquifers and six prospects have been evaluated in terms of storage capacity and safe storage of CO2. One identified storage potential is the Froan Basin Garn and Ile Formations. The Froan Basin is a NE striking Jurassic syncline on the southwestern part of the Trøndelag Platform. The aquifers in the southeastern part of the Norwegian Sea typically have a consistent dip of 1-2 degrees from the Norwegian coast to the basinal areas. In the case of permeable beds occurring along the dip slope there is a risk that CO2 injected down dip can migrate up to where the aquifer is truncated by the Quaternary glacial sediments. A simulation study was performed in order to identify possible trapping mechanisms and to understand the timing and extent of long distance CO2 migration. The storage mechanisms considered were both structural and stratigraphic trapping. A simulation sector model of the Garn/Not/Ile Formations was build covering about 10% of the total expected communicating aquifer volume. The CO2 injection well was located down dip, but alternative locations and injection zones have been simulated, with different injection rates. The injection period is 50 years, and the migration of the CO2 plume was simulated and monitored for 10.000 years. CO2 will continue to migrate upwards as long as it is in free, movable state. Migration stops when CO2 is permanently bounded or trapped, by going into solution with the formation water or by being residually trapped, or becoming structurally trapped (mineralogical trapping not considered). Based on simulation results about 400 mill tons CO2 can be stored in the Garn and Ile aquifer (8 mill tons/year over 50 years). This will require 4 injection and give acceptable pressure increase (<20bar). Within 10000 years most of the gas will have gone into solution with the formation water or being residually trapped.

  9. Feeding Ecology of Northeast Atlantic Mackerel, Norwegian Spring-Spawning Herring and Blue Whiting in the Norwegian Sea.

    PubMed

    Bachiller, Eneko; Skaret, Georg; Nøttestad, Leif; Slotte, Aril

    2016-01-01

    The Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting (Micromesistius poutassou) and Northeast Atlantic (NEA) mackerel (Scomber scombrus) are extremely abundant pelagic planktivores that feed in the Norwegian Sea (NS) during spring and summer. This study investigated the feeding ecology and diet composition of these commercially important fish stocks on the basis of biological data, including an extensive set of stomach samples in combination with hydrographical data, zooplankton samples and acoustic abundance data from 12 stock monitoring surveys carried out in 2005-2010. Mackerel were absent during the spring, but had generally high feeding overlap with herring in the summer, with a diet mainly based on calanoid copepods, especially Calanus finmarchicus, as well as a similar diet width. Stomach fullness in herring diminished from spring to summer and feeding incidence was lower than that of mackerel in summer. However, stomach fullness did not differ between the two species, indicating that herring maintain an equally efficient pattern of feeding as mackerel in summer, but on a diet that is less dominated by copepods and is more reliant on larger prey. Blue whiting tended to have a low dietary overlap with mackerel and herring, with larger prey such as euphausiids and amphipods dominating, and stomach fullness and feeding incidence increasing with length. For all the species, feeding incidence increased with decreasing temperature, and for mackerel so did stomach fullness, indicating that feeding activity is highest in areas associated with colder water masses. Significant annual effects on diet composition and feeding-related variables suggested that the three species are able to adapt to different food and environmental conditions. These annual effects are likely to have an important impact on the predation pressure on different plankton groups and the carrying capacity of individual systems, and emphasise the importance of regular monitoring of pelagic fish diets. PMID:26895485

  10. Feeding Ecology of Northeast Atlantic Mackerel, Norwegian Spring-Spawning Herring and Blue Whiting in the Norwegian Sea

    PubMed Central

    Bachiller, Eneko; Skaret, Georg; Nøttestad, Leif; Slotte, Aril

    2016-01-01

    The Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting (Micromesistius poutassou) and Northeast Atlantic (NEA) mackerel (Scomber scombrus) are extremely abundant pelagic planktivores that feed in the Norwegian Sea (NS) during spring and summer. This study investigated the feeding ecology and diet composition of these commercially important fish stocks on the basis of biological data, including an extensive set of stomach samples in combination with hydrographical data, zooplankton samples and acoustic abundance data from 12 stock monitoring surveys carried out in 2005–2010. Mackerel were absent during the spring, but had generally high feeding overlap with herring in the summer, with a diet mainly based on calanoid copepods, especially Calanus finmarchicus, as well as a similar diet width. Stomach fullness in herring diminished from spring to summer and feeding incidence was lower than that of mackerel in summer. However, stomach fullness did not differ between the two species, indicating that herring maintain an equally efficient pattern of feeding as mackerel in summer, but on a diet that is less dominated by copepods and is more reliant on larger prey. Blue whiting tended to have a low dietary overlap with mackerel and herring, with larger prey such as euphausiids and amphipods dominating, and stomach fullness and feeding incidence increasing with length. For all the species, feeding incidence increased with decreasing temperature, and for mackerel so did stomach fullness, indicating that feeding activity is highest in areas associated with colder water masses. Significant annual effects on diet composition and feeding-related variables suggested that the three species are able to adapt to different food and environmental conditions. These annual effects are likely to have an important impact on the predation pressure on different plankton groups and the carrying capacity of individual systems, and emphasise the importance of regular monitoring of pelagic fish diets. PMID:26895485

  11. Validation of ECMWF and DWD model analyses with buoy measurements over the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Lammert, Andrea; Brmmer, Burghard; Ebbers, Irina; Mller, Gerd

    2008-11-01

    As part of the Lofote Cyclone experiment (Lofoten Zyklonen Experiment) 21 drift buoys were deployed in a 700 km 400 km area of the Norwegian Sea situated to the west of the Lofote Islands. The buoys measured sea-level pressure (SLP), surface air temperature (SAT), and sea surface temperature (SST) at hourly intervals for a 6-month period from March to August 2005. This unique data set is used to validate the operational model analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the German Weather Service [Deutscher Wetterdienst (DWD)]. Comparisons were performed in both time and space. Generally, biases are small and amount to 0.2 hPa for SLP and -0.2 K for SAT. Temporal correlations are higher than 0.99 for SLP and 0.93 for SAT. Spatial correlations as a measure of pattern coincidence are lower then for temporal correlations, but still amount to values higher than 0.97 for SLP and 0.76 for SAT on average. SST, which is externally prescribed and not a model variable, shows surprisingly large and persistent errors of up to 6 K for latitudes above 76N. This points towards basic errors in the SST source for both models. Taking all comparisons (SLP, SAT, and SST) together, agreement is slightly worse for DWD than for ECMWF.

  12. Sequence stratigraphy and stratigraphic simulation of the Brent Group, Norwegian North Sea

    SciTech Connect

    Prueser, R.E.; Levine, P.A.; Baum, G.R.; Kendall, G.S.C.

    1996-12-31

    Sequence stratigraphic analysis of a well log data base from the Norwegian North Sea has established that the Brent Group is a deltaic complex consisting of four third-order depositional sequences. Sequence 1 was deposited first during northwestern progradation of the delta from the Horda Platform, while sequences 2 and 3 were primarily aggradational. Sequence 4 is characterized by backslapping geometries and a basin wide drowning event which resulted from variably increasing subsidence rates across the basin. The stratigraphic events interpreted in this study are based on the identification of unconformities (sequence boundaries), transgressive surfaces, and maximum flooding surfaces. Dates for these events were established using biostratigraphy from 12 wells. Unlike earlier interpretations, the Oseberg Formation is considered to be part of Sequence 1 and is an incised-valley fill which is genetically related to the distal Rannoch and Etive formations. Also in this study, a new sea level curve is proposed for the Aalenian - Bathonian which has similar frequencies to the Exxon sea level chart, but much smaller amplitudes. This interpretation was simulated in order to estimate the sea level, subsidence, and sediment supply parameters involved in deposition of these sequences. Simulation results indicate that the main deposition of the Brent Group occurred during uniform subsidence, while drowning of the depositional system resulted from a sharp, but variable increase in subsidence rates across the basin. Quantitative comparisons between the lithologic percentages in each sequence at well locations and at representative points in the simulation confirm that the simulation presents a unique and reasonable answer.

  13. Sequence stratigraphy and stratigraphic simulation of the Brent Group, Norwegian North Sea

    SciTech Connect

    Prueser, R.E.; Levine, P.A.; Baum, G.R.; Kendall, G.S.C. )

    1996-01-01

    Sequence stratigraphic analysis of a well log data base from the Norwegian North Sea has established that the Brent Group is a deltaic complex consisting of four third-order depositional sequences. Sequence 1 was deposited first during northwestern progradation of the delta from the Horda Platform, while sequences 2 and 3 were primarily aggradational. Sequence 4 is characterized by backslapping geometries and a basin wide drowning event which resulted from variably increasing subsidence rates across the basin. The stratigraphic events interpreted in this study are based on the identification of unconformities (sequence boundaries), transgressive surfaces, and maximum flooding surfaces. Dates for these events were established using biostratigraphy from 12 wells. Unlike earlier interpretations, the Oseberg Formation is considered to be part of Sequence 1 and is an incised-valley fill which is genetically related to the distal Rannoch and Etive formations. Also in this study, a new sea level curve is proposed for the Aalenian - Bathonian which has similar frequencies to the Exxon sea level chart, but much smaller amplitudes. This interpretation was simulated in order to estimate the sea level, subsidence, and sediment supply parameters involved in deposition of these sequences. Simulation results indicate that the main deposition of the Brent Group occurred during uniform subsidence, while drowning of the depositional system resulted from a sharp, but variable increase in subsidence rates across the basin. Quantitative comparisons between the lithologic percentages in each sequence at well locations and at representative points in the simulation confirm that the simulation presents a unique and reasonable answer.

  14. CloudSat First Image of a Warm Front Storm Over the Norwegian Sea

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Figure 1

    CloudSat's first image, of a warm front storm over the Norwegian Sea, was obtained on May 20, 2006. In this horizontal cross-section of clouds, warm air is seen rising over colder air as the satellite travels from right to left. The red colors are indicative of highly reflective particles such as water droplets (or rain) or larger ice crystals (or snow), while the blue indicates thinner clouds (such as cirrus). The flat green/blue lines across the bottom represent the ground signal. The vertical scale on the CloudSat Cloud Profiling Radar image is approximately 30 kilometers (19 miles). The blue line below the Cloud Profiling Radar image indicates that the data were taken over water. The inset image shows the CloudSat track relative to a Moderate Resolution Imaging Spectroradiometer (MODIS) infrared image taken at nearly the same time.

  15. Evaluation of Nimbus 7 SMMR sensor with airborne radiometers and surface observations in the Norwegian Sea

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Cavalieri, D.; Crawford, J.; Campbell, W. J.; Farrelly, B.; Johannessen, J.; Johannessen, O. M.; Svendsen, E.; Kloster, K.

    1981-01-01

    Measurements made by the Nimbus 7 SMMR are compared with near simultaneous observations using the airborne SMMR simulator and with surface observations. The area of the test is in the Norwegian Sea between Bear Island and Northern Norway. It is noted that during the observation period two low-pressure systems were located in the test area, giving a spatial wind variation from 3-20 m/s. It is shown that the use of the currently available brightness temperatures and algorithms for SMMR does not give universally satisfactory results for SST and wind speed under extreme weather conditions. In addition, the SMMR simulator results are seen as indicating the need for more work on calibration.

  16. Oceanic distribution and life cycle of Calanus species in the Norwegian Sea and adjacent waters

    NASA Astrophysics Data System (ADS)

    Broms, Cecilie; Melle, Webjrn; Kaartvedt, Stein

    2009-10-01

    The distribution and demography of Calanus finmarchicus, C. glacialis and C. hyperboreus were studied throughout their growth season on a basin scale in the Norwegian Sea using ordination techniques and generalized additive models. The distribution and demographic data were related to the seasonal development of the phytoplankton bloom and physical characteristics of water masses. The resulting quantified relationships were related to knowledge on life cycle and adaptations of Calanus species. C. finmarchicus was the numerically dominant Calanus species in Coastal, Atlantic and Arctic waters, showing strong association with both Atlantic and Arctic waters. C. hyperboreus and C. glacialis were associated with Arctic water; however, C. glacialis was occasionally observed in the Norwegian Sea and is probably an expatriate advected into the area from various origins. Demography indicated one generation per year of C. finmarchicus, a two-year life cycle of C. hyperboreus, and both one- and two-year life cycles for C. glacialis in the water masses where they were most abundant. For the examined Calanus species, young copepodites of the new generation seemed to be tuned to the phytoplankton bloom in their main water mass. The development of C. finmarchicus was delayed in Arctic water, and mis-match between feeding stages and the phytoplankton bloom may reduce survival and reproductive success of C. finmarchicus in Arctic water. Based on low abundances of C. hyperboreus CI-III in Atlantic water and main recruitment to CI prior to the phytoplankton bloom, we suggest that reproduction of C. hyperboreus in Atlantic water is not successful.

  17. Variations in bio-optical properties in the Greenland/Iceland/Norwegian seas

    NASA Astrophysics Data System (ADS)

    Dallokken, Runar; Sandvik, Roar; Sakshaug, Egil

    1994-10-01

    Diffuse attenuation coefficients for spectral irradiance Kd((Zeta) (lambda) ) and the total Chl (alpha) + Pheo (alpha) pigment-specific absorption of light by particles ((alpha) p*((lambda) ), algae + detritus), were determined during two cruises (Cardeep 2 and 3) in the Greenland/Iceland/Norwegian (GIN)-Seas. The pigment (Chl (alpha) + Pheo (alpha) ) specific attenuation coefficient Kd*((lambda) ) was compared with Morel's non-linear model for light propagation of solar energy in the ocean and with the pigment specific absorption coefficient by particles, (alpha) p*. Our Kd*((lambda) ) spectrum for the GIN-Seas was in good agreement with values derived from Morel's model for pigment specific light attenuation for 1 mg (Chl (alpha) + Pheo (alpha) ) m-3 for wavelengths in the blue part of the spectrum. Kd*((lambda) ) (apparent optical property) and ap*((lambda) ) (inherent optical property), were in good agreement except at wavelengths > 665 and < 441 nm. This was only true for the (alpha) p*((lambda) ) spectra for which the optical density from 750 - 800 nm was not subtracted.

  18. The life cycle of Anisakis simplex in the Norwegian Deep (northern North Sea).

    PubMed

    Klimpel, Sven; Palm, Harry W; Rckert, Sonja; Piatkowski, Uwe

    2004-09-01

    Copepoda (Calanus finmarchicus n = 1,722, Paraeuchaeta norvegica n = 1,955), Hyperiidae (n = 3,019), Euphausiacea (Meganyctiphanes norvegica n = 4,780), and the fishes Maurolicus muelleri (n = 500) and Pollachius virens (n = 33) were collected in the Norwegian Deep (northern North Sea) during summer 2001 to examine the importance of pelagic invertebrates and vertebrates as hosts of Anisakis simplex and their roles in the transfer of this nematode to its final hosts (Cetaceans). Third stage larvae (L3) of A. simplex were found in P. norvegica, M. muelleri and P. virens. The prevalence of A. simplex in dissected P. norvegica was 0.26%, with an intensity of 1. Prevalences in M. muelleri and P. virens were 49.6% and 100.0%, with mean intensities of 1.1-2.6 (total fish length >or=6.0-7.2) and 193.6, respectively. All specimens of C. finmarchicus and M. norvegica examined were free of anisakid nematode species and no other parasites were detected. P. norvegica, which harboured the third stage larvae, is the obligatory first intermediate host of A. simplex in the investigated area. Though there was no apparent development of larvae in M. muelleri, this fish can be considered as the obligatory second intermediate host of A. simplex in the Norwegian Deep. However, it is unlikely that the larva from P. norvegica can be successfully transmitted into the cetacean or pinniped final hosts, where they reach the adult stage. An additional growth phase and a second intermediate host is the next phase in the life cycle. Larger predators such as P. virens serve as paratenic hosts, accumulating the already infective stage from M. muelleri. The oceanic life cycle of A. simplex in the Norwegian Deep is very different in terms of hosts and proposed life cycle patterns of A. simplex from other regions, involving only a few intermediate hosts. In contrast to earlier suggestions, euphausiids have no importance at all for the successful transmission of A. simplex in the Norwegian Deep. This demonstrates that this nematode is able to select definite host species depending on the locality, apparently having a very low level of host specificity. This could explain the wide range of different hosts that have been recorded for this species, and can be seen as the reason for the success of this parasite in reaching its marine mammal final hosts in an oceanic environment. PMID:15278439

  19. Pleistocene glaciation history of the Northern North Sea and Norwegian Channel documented by basin-scale 3D seismic analysis

    NASA Astrophysics Data System (ADS)

    Huuse, J.; Huuse, M.

    2012-04-01

    A regionally merged (c. 30,000 km2) 'megasurvey' 3D seismic dataset and an extensive set of 2D lines, tied to the Troll (89-03) core and wireline logs, was used to investigate the glacial and inter-glacial evolution of the northernmost North Sea through the Plio-Pleistocene. An extensive regional unconformity (URU) exists throughout the study area truncating the Naust Formation, a Plio-Pleistocene glacially-influenced progradational delta system, and older strata. This major erosion surface forms the base of the Norwegian Channel, a large (800 km long) cross-shelf trough located along the southern Norwegian coast. The evolution and exact erosion mechanism of this enigmatic feature is still debated. The stratigraphic succession above the URU consists of relatively flat-lying, alternating glacial and glacio-marine units of mid Pleistocene-Holocene age. This study is the first to present fully 3D seismic-constrained maps of the URU, the Naust clinoforms and all major glacial erosion surfaces within the Norwegian Channel infill. Furthermore it documents the geometries and sedimentary facies characteristics of the till and marine units preserved within the Norwegian Channel and the Norwegian sector of the Northern North Sea. Mapped erosional surfaces reveal a diverse assemblage of glacial morpologies interpreted as mega-scale glacial lineations, tunnel valleys, glaciotectonic thrust complexes, terminal moraines and meltwater conduits demarcating the terminus of successive grounded palaeo-ice sheets. Ice berg ploughing was common along the margin between 2.6 and 1.1 Ma with ice streaming commencing prior to 1.1 Ma. Repeated occupation of the NC by fast flowing ice streams, during the Elsterian, Saalian, and Weichselian (MIS 12, 10, 8, 6, 2), led to a progressively westward erosion of the channel margin, migrating approximately 60 km between 1.1 Ma and the LGM. Although well imaged by seismic data, the prolific record of glaciations and interglacials in the Northern North Sea require better age constraints to further fine tune the record of Pleistocene environmental changes. Whilst a large number of wells exist in the North Sea, giving basic lithological information, only very few have sufficiently detailed stratigraphic data in the Pleistocene section. Further research should thus include coring tied to high-resolution seismic data that can be linked to the basin-scale 3D seismic observations presented herein. As this study provides a unique insight into the spatial and temporal dynamics of shelf-edge glaciation in the northern North Sea and its Atlantic margin throughout the late Cenozoic, the plethora of features documented within the Northern North Sea may serve as a template for interpreting other less well imaged glaciated margins.

  20. Gas migration and carbon capture in one of the World's largest pockmark fields, the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Mazzini, A.; Svensen, H.; Planke, S.; Hammer, O.; Linge, H. C.; Forsberg, C. F.; Tjelta, T.

    2013-12-01

    Acoustic imaging has revealed more than 7000 pockmarks above the Troll East gas field in the Norwegian Sea. The pockmarks range in size from 10 to 100 meters in diameter and are typically 6 meters deep. High-resolution bathymetric data shows that there is no evidence of structural control on the location of the pockmarks. This conclusion is in agreement with statistical analysis of the pockmark distribution which shows neighbor avoidance up to a scale of hundreds of meters and no indication of a fractal geometry. The pockmarks generally represent isolated structures and sometimes are identified in clusters with a central parent pockmark surrounded by smaller sized satellite pockmarks. Seafloor observations show that carbonate deposits are common within the pockmarks, providing shelter to the local fauna. Carbonate blocks collected from the pockmarks showed evidence for three distinct generations including micritic Mg-calcite/aragonite, micritic aragonite, and botryoidal aragonite. The carbon isotopic values of these phases are 13C depleted and 18O enriched, indicating a methanogenic origin and possibly a component sourced from dissociation of gas hydrates. Water geochemistry from shallow cores within and outside the pockmarks gave no indication of active seepage. This conclusion is further supported by no direct observations of fluid flow within the pockmarks, no bacterial mats nor obvious chemosymbiotic communities. In addition, oxidized carbonate surfaces indicate a gradual excavation and exposure at the sea floor. We conclude that one of the world's largest pockmark fields is currently inactive and that its formation is likely related to deglaciation processes about 11 ky ago.

  1. Airborne Measurements of Emissions from Oil and Gas Exploration and Production Activities in the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Kim, J.; Roiger, A.; Raut, J.; Rose, M.; Weinzierl, B.; Reiter, A.; Thomas, J. L.; Marelle, L.; Law, K.; Schlager, H.

    2013-12-01

    A rapid decline of Arctic sea ice is expected to promote hydrocarbon extraction in the Arctic, which in turn will increase emissions of atmospheric pollutants. To investigate impacts of different pollution sources on the Arctic atmosphere, an aircraft campaign based in northern Norway was conducted in July 2012, as a part of the EU ACCESS (Arctic Climate Change Economy and Society) project. One of the flights focused on measuring emissions from various oil/gas exploration and production facilities ~110 km south of the Arctic Circle in the Norwegian Sea. Fresh and aged (from 5 minutes to 2.5 hours old) exhaust plumes from oil/gas production platforms, drilling rigs and tankers were probed with extensive aerosol and trace gas instrumentations. It was found that different types of facilities emit plumes with distinct chemical compositions. For example, tanker plumes were characterized by high SO2 concentration and high fraction of non-volatile particles while plumes from oil/gas production platforms showed significant increase in the nucleation mode particle concentration. Drilling rigs were found to be high black carbon emitters. In addition to the fresh plumes, relatively aged plumes (1.5 - 2.5 hours old) from a facility under development were measured. Even in these aged plumes, total particle concentrations were more than 6 times higher than the background concentration. Therefore, emissions from oil and gas activities are expected to have a significant impact on local air quality and atmospheric composition. With the aid of FLEXPART-WRF (a Lagrangian dispersion model) simulations, the results of this study will be used to validate and improve current emission inventories. In the future, these improved emission inventories can be used in regional and global chemical transport models to more accurately predict future Arctic air pollution.

  2. Norwegian Research Strategies on gas Hydrates and Natural Seeps in the Nordic Seas Region (GANS)

    NASA Astrophysics Data System (ADS)

    Hjelstuen, B. O.; Sejrup, H. P.; Andreassen, K.; Boe, R.; Eldholm, O.; Hovland, M.; Knies, J.; Kvalstad, T.; Kvamme, B.; Mienert, J.; Pedersen, R. B.

    2004-12-01

    Continuous leakage of methane to the oceans from hydrate reservoirs that partially are exposed towards the seafloor is an increasing international concern, as the greenhouse gas methane is significantly more (c. 20 times) aggressive than CO2. In Norway we have research groups with interest and experience on natural seeps and gas hydrates. These features, and processes related to them, are challenging research targets which demands inputs from different fields if important research breakthroughs shall be made. In February 2004 deep sea researchers from the University of Tromso, Geological Survey of Norway, Norwegian Geotechnical Institute, Statoil and University of Bergen met to obtain an overview of the research effort in the fields of natural seeps and gas hydrates in Norway and to discuss national coordination, research strategies, research infrastructure and international co-operation. The following research strategies were agreed upon: i) Strengthen multidisciplinary research on deep sea systems, ii) develop a strategy for research on natural seeps and gas hydrates, iii) contribute in national coordination of research on natural seeps and gas hydrates, iv) Coordinate the use and development of research infrastructures important for research on natural seeps and gas hydrates, and v) contribute in the international evaluations of strategies for hydrate reservoir exploitation. Proposed research tasks for GANS include: i) Gas and gas hydrate formation processes and conditions for transport, accumulation, preservation and dissociation in sediments, ii) Effect of gas hydrate on physical properties of sediment, iii) Detection and quantification of in situ gas hydrate content and distribution pattern, iv) Effect of dissociation on soil properties, v) Gas hydrates as an energy resource, vi) Rapid methane release and climate change, and vii) Geohazard and environmental impact.

  3. Salt distribution in the Norwegian-Danish Basin, Central North Sea

    NASA Astrophysics Data System (ADS)

    Sassier, Caroline; Jarsve, Erlend; Heeremans, Michel; Mansour Abdelmalak, Mohamed; Faleide, Jan Inge; Helge Gabrielsen, Roy

    2014-05-01

    Salt tectonics have extensively been studied in most parts of the Central North Sea. However, few studies have been done in the Norwegian side of the Norwegian-Danish Basin. In this contribution, we report a new regional analysis of the salt patterns across the offshore Norwegian-Danish Basin. We have mapped the regional distribution of salt structures in the Norwegian-Danish Basin using both old and recent 2D seismic reflection profiles tied to wells. The salt-thickness map shows three distinct salt structures patterns: (1) NW-SE trending salt walls in the northern part of the basin; the spacing between the walls vary between 7 to 12 km; (2) a dense and irregular distribution of salt diapirs in the southern part of the studied area; (3) an irregular pattern of sparse but big salt diapirs in the eastern part of the basin. This domain is characterized by numerous turtle structures associated with salt diapirs. Reflection seismic cross-sections show that most salt structures only pierce the Triassic sedimentary strata whereas only few salt structures reach the seabed. Rotated fault blocks indicate a gliding vergence towards the South in the eastern part of the basin and towards the SE in the western side of the Norwegian-Danish Basin. No mature or compressive salt structures, except some squeezed salt diapirs, are observed in the topographic lows of the basin. The initiation of salt tectonics started during the early Middle Triassic in the entire basin; salt tectonics reactivations were recorded during the Middle Jurassic, Paleogene, and prior to the Quaternary but are not homogeneous across the basin. Salt movements inferred from our study are in good agreement with previous studies. The trend of salt walls (domain 1) indicates a NE-SW extension which is not compatible with N-S trending pre-salt faults. Instead, the strong Triassic subsidence towards the SW has most likely controlled the formation of the salt walls. The salt was initially thicker in domain 2 that also corresponds to the main depocenter of the first Triassic sequence. We suggest that both the salt thickness and the sedimentary differential loading, combined with the subsidence of the basin, have influenced the change of the salt pattern in domain 2. In domain 3, the reactivation of pre-salt faults might have triggered some of the salt structures. This area also received a large amount of sediments from the Skagerrak area during the Triassic subsidence, which may have influenced the distribution and evolution of salt diapirs and turtle structures. The combination of the different triggering processes and the different basin geometry of domain 3, which is bounded by highs to the South and North, in comparison to domain 2 which is open towards the Central Graben, are probably the key parameters that have controlled the salt pattern in this area. Finally, salt tectonics reactivations were likely controlled by the distribution of younger sediments and the successive tectonic regimes.

  4. Influence of lithofacies and diagensis on Norwegian North Sea chalk reservoirs

    SciTech Connect

    Brasher, J.E.; Vagle, K.R.

    1996-05-01

    The depositional mechanism of chalk is a key influence in the chalk`s ultimate reservoir quality. Classically, the depositional mechanism is interpreted from core descriptions. Where core data are lacking, dipmeter and borehole imagery logs have proven useful in making lithofacies assessments. Criteria for recognition of three chalk categories are established. Category III chalks correspond to those chalks that have been deposited by gravity flows or slumping and tend to have the best reservoir parameters. Category I chalks are most often affiliated with pelagic deposition and tend to have the poorest reservoir parameters. Category II chalks are intermediate between I and III. Anomalously high primary porosities have been maintained in Norwegian North Sea chalks where the effects of mechanical and chemical compaction have been limited. The diagenetic pathway of a chalk reflects changes brought about by mechanical and chemical compaction. Five factors most heavily influence the diagenetic pathway: (1) burial depth, (2) chalk type, (3) overpressuring, (4) presence of hydrocarbons, and (5) original grain size. Assessments of the sedimentological model, diagenetic pathway, and resultant reservoir quality are provided in case studies of Edda, Tor, and Eldfisk fields. Because the distribution of chalk is largely independent of existing structures, most fields have a component of stratigraphic/diagenetic trapping. Each case study shows unique examples of how petrophysical and reservoir engineering data can be incorporated in assessments of chalk type and the diagenetic pathway and how they may affect reservoir parameters and productivity.

  5. Conjugate volcanic rifted margins, spreading and micro-continent: Lessons from the Norwegian-Greenland Sea

    NASA Astrophysics Data System (ADS)

    Gernigon, L.; Blischke, A.; Nasuti, A.; Sand, M.

    2014-12-01

    We have acquired and processed new aeromagnetic data that covers the entire Norway Basin oceanic spreading system located between the Møre volcanic rifted margin and its (intermediate) conjugate system, the Jan Mayen microcontinent (JMMC). The new compilation allows us to revisit its entire structure and spreading evolution from the Early Eocene breakup to the Late Oligocene abortion of the Aegir Ridge. We here discuss the dynamics of conjugate volcanic (rifted) margin formation and reconstruct the subsequent spreading evolution of the Norway Basin until its abortion. We have estimated a new set of Euler poles of rotation for the Norway Basin derived from more than 88,000 km of new magnetic profiles. The new compilation confirms that a fan-shaped spreading evolution of the Norway Basin was particularly active before the cessation of seafloor spreading and abortion of the Aegir Ridge. The Norway Basin shows a more complex system of micro-plates and asymmetric segments locally affected by episodic ridge jumps. The new observations have implications for the syn- and post-breakup stratigraphic and rifted-margin tectonic development of the JMMC and its conjugate margins. In particular, an important Mid-Eocene geodynamic event at around magnetic chron C21r is recognized in the Norway Basin. This event coincides with the onset of diking and rifting between the proto-JMMC and the East Greenland margin, leading to a second phase of breakup in the Norwegian-Greenland Sea ~26 My later in the Oligocene. Restored in its pre-breakup configuration, the new surveys also allow us to discuss further the tectonic and crustal evolution of the conjugate volcanic rifted margins and associated transform and oblique segments. The applicability of magma-poor concepts, off Norway, for example, remains questionable for us. The significant amount of breakup magmatism, the huge amount of pre-breakup sag sedimentation and the presence of thinned and preserved continental crust without the systematic occurrence of underlying and/or exhumed serpentinised terranes. The mid-Norwegian volcanic rifted margins appear quite different from the Iberian type, magma-poor margin, even if the processes leading to the early (and aborted) thinning events seems to be similar to some extent.

  6. Water mass exchanges between the Norwegian and Iceland seas over the Jan Mayen Ridge using in-situ current measurements

    NASA Astrophysics Data System (ADS)

    Mork, Kjell Arne; Drinkwater, Kenneth F.; Jnsson, Steingrmur; Valdimarsson, Hinn; Ostrowski, Marek

    2014-11-01

    The Jan Mayen Ridge, with bottom depths of 1000 m and less, runs southwards from Jan Mayen and separates the warmer and saltier Atlantic Water in the Norwegian Sea from the colder and fresher Arctic water in the Iceland Sea. During the International Polar Year (IPY, 2007-2008), three current meter moorings were deployed with the purpose to investigate water mass exchanges between the Norwegian and Iceland seas over the Ridge and their forcing mechanisms. These are the first in-situ current measurements for this region. The results showed relatively weak currents on the Ridge that frequently shifted direction except near-bottom and at the western slope of the Ridge. All current measurements showed low eddy activity and tidal velocities (less than 0.05 ms- 1). Wind-forced near-inertial motion generated from transient atmospheric low pressure systems were observed in the mixed layer being strongest during autumn and winter when ocean velocities reached 0.7 ms- 1. Near surface currents on the Ridge are influenced by local winds on a time scale of 6 days and longer, but during the two-year deployment no pronounced seasonal variation was observed, mainly due to a lack of seasonality in the local winds. In a 2000 m deep channel that cuts the Ridge, there was pronounced seasonal variation in the currents at all depths below 40 m with stronger flow toward the Iceland Sea during winter compared to summer. The variability of the deep current was found to be influenced by the large-scale wind stress curl. There was a weak net flow with averaged velocities of ~ 0.01 ms- 1 over the Ridge that was directed westward in the upper layer, signifying a small net transport of modified Atlantic Water into the Iceland Sea.

  7. [Variation of ecological status of Norwegian Sea water determined from hydrolytic enzyme activities].

    PubMed

    Korneeva, G A; Gorfeeva, E L; Shevchenko, V P

    2005-01-01

    The capacity of biopolymer transformation involving efficient and highly specific natural enzyme mechanisms was studied in seawater of the dynamic zone of the Norwegian Sea (the Voring Plateau region). Vertical and spatial variation of proteinase and amylase activities was demonstrated in seawater and the potential rates of degradation of specific substrates, azocasein and Procion-5CX-modified starch, were calculated. High proteolytic activity was demonstrated for the upper photic layer (0-10 m) in the southwestern part of the polygon (up to 88 U/l; v(pr) = 7.04 mg/l/h). Proteolytic activity in the abyssal layer (1500 m and below) sharply decreased to 8-16 U/1; v(pr) = 0.64-1.28 mg/l/h. Similar to other regions of the ocean, the pattern of amylase activity in seawater included low rates of polysaccharide destruction (0-4 U/I; v(st) = 0-0.2 mg/l/h) in water with high proteolytic capacity and, conversely, the top amylase activity (up to 246-490 U/l; v(st) 12.3-24.5 mg/l/h) in seawater layers with undetectable or low proteolytic activity. The spatial distribution of the enzyme activities can indicate the presence of water bodies of different genesis. In the southwestern part of the polygon, statistical analysis demonstrated high correlation between hydrophysical indices (temperature, salinity, and salinity gradient) and proteinase and amylase activities. The ecological evaluation based on express enzyme-substrate tests demonstrated a stressful situation for destruction of organic compounds of protein nature in both the photic layer and the layers below 1000 m (t(pr) > or = 10 h). PMID:16212269

  8. Wave height analysis from 10 years of observations in the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Feng, Xiangbo; Tsimplis, M. N.; Quartly, G. D.; Yelland, M. J.

    2014-01-01

    Large waves pose risks to ships, offshore structures, coastal infrastructure and ecosystems. This paper analyses 10 years of in-situ measurements of significant wave height (Hs) and maximum wave height (Hmax) from the ocean weather ship Polarfront in the Norwegian Sea. During the period 2000 to 2009, surface elevation was recorded every 0.59 s during sampling periods of 30 min. The Hmax observations scale linearly with Hs on average. A widely-used empirical Weibull distribution is found to estimate average values of Hmax/Hs and Hmax better than a Rayleigh distribution, but tends to underestimate both for all but the smallest waves. In this paper we propose a modified Rayleigh distribution which compensates for the heterogeneity of the observed dataset: the distribution is fitted to the whole dataset and improves the estimate of the largest waves. Over the 10-year period, the Weibull distribution approximates the observed Hs and Hmax well, and an exponential function can be used to predict the probability distribution function of the ratio Hmax/Hs. However, the Weibull distribution tends to underestimate the occurrence of extremely large values of Hs and Hmax. The persistence of Hs and Hmax in winter is also examined. Wave fields with Hs>12 m and Hmax>16 m do not last longer than 3 h. Low-to-moderate wave heights that persist for more than 12 h dominate the relationship of the wave field with the winter NAO index over 2000-2009. In contrast, the inter-annual variability of wave fields with Hs>5.5 m or Hmax>8.5 m and wave fields persisting over ~2.5 days is not associated with the winter NAO index.

  9. On the ecology of Calanus finmarchicus in the Subarctic North Atlantic: A comparison of population dynamics and environmental conditions in areas of the Labrador Sea-Labrador/Newfoundland Shelf and Norwegian Sea Atlantic and Coastal Waters

    NASA Astrophysics Data System (ADS)

    Head, Erica J. H.; Melle, Webjørn; Pepin, Pierre; Bagøien, Espen; Broms, Cecilie

    2013-07-01

    The Norwegian Sea is generally warmer than the Labrador Sea because it is influenced more by Atlantic Water inflows from the south, whereas the latter receives relatively larger inputs of Arctic Water from the north. Despite its more northerly location, the spring bloom generally starts earlier in the Norwegian Sea. Within each of the two seas, however, there are regional and interannual differences in temperature and the timing of the spring bloom. The responses of Calanus finmarchicus populations to these differences in environmental conditions include differences in physical characteristics (e.g. female size), physiological rates (egg production rates) and seasonal cycles of abundance. Females are generally larger in the Labrador Sea and have higher egg production rates for a given chlorophyll concentration than do those in the Norwegian Sea. Within and among areas in both seas, as temperatures increase and spring blooms tend to occur earlier, C. finmarchicus start to reproduce earlier, the new generation develops faster, and in some areas a second generation ensues. In areas where near surface temperatures are relatively high in summer and/or where phytoplankton growth rates are relatively low in summer or autumn, reproduction and development cease, and C. finmarchicus desert the surface layers for their overwintering depths. This occurs in the Norwegian Sea in summer and in the central Labrador Sea in autumn. By contrast, in areas where near surface temperatures remain cool in summer and where phytoplankton growth persists through the autumn, reproduction and development can continue through summer and autumn, probably until winter vertical mixing prevents phytoplankton growth. This occurs on the southern Newfoundland Shelf. Even in areas where the growth season is prolonged, however, a proportion of the first generation, and probably subsequent generations, descends to overwinter. If the size of the overwintering population is used as an index of net productivity, then for equivalent regions in the Norwegian Sea and Labrador Sea (the areas of each most affected by Atlantic inflow), the differences in ambient temperatures and bloom dynamics apparently have little impact. With global warming, as temperatures in the Norwegian and Labrador Seas increase up to a certain threshold, the timing of life history events for C. finmarchicus will likely be advanced and the number of generations produced per year could increase. The time spent in the near surface layers will probably decrease, however, while the overall effect on population size may not be large. Once the temperature threshold for unfavourable survival of C. finmarchicus has been exceeded, the distribution range for C. finmarchicus will likely contract northwards, with important consequences for dependent species in the affected regions.

  10. The coccolithophores Emiliania huxleyi and Coccolithus pelagicus: Extant populations from the Norwegian-Iceland Seas and Fram Strait

    NASA Astrophysics Data System (ADS)

    Dylmer, C. V.; Giraudeau, J.; Hanquiez, V.; Husum, K.

    2015-04-01

    The distributions of the coccolithophore species Emiliania huxleyi and Coccolithus pelagicus (heterococcolith-bearing phase) in the northern North Atlantic were investigated along two zonal transects crossing Fram Strait and the Norwegian-Iceland Sea, respectively, each conducted during both July 2011 and September-October 2007. Remote-sensing images as well as CTD and ARGO profiles were used to constrain the physico-chemical state of the surface water and surface mixed layer at the time of sampling. Strong seasonal differences in bulk coccolithophore standing stocks characterized the northern and southern transects, where the maximum values of 53×103 cells/l (fall) and 70×103 cells/l (summer), respectively, were essentially explained by E. huxleyi. This pattern confirms previous findings of a summer to fall northwestward shift in peak coccolithophore cell densities within the Nordic Seas. While depicting an overall zonal shift in high cell densities between the summer (Norwegian Sea) and fall (northern Iceland Sea) conditions, the southern transects were additionally characterized by local peak coccolithophore concentrations associated with a geographically and temporally restricted convective process (Lofoten Gyre, summer), as well as an island mass effect (in the vicinity of Jan Mayen Island, fall). Maximum coccolithophore abundances within Fram Strait were found during both seasons close to the western frontal zone (Polar and Arctic Fronts) an area of strong density gradients where physical and chemical properties of the surface mixed layer are prone to enhance phytoplankton biomass and productivity. Here, changes in species dominance from E. huxleyi in summer, to C. pelagicus in fall, were related to the strengthened influence during summer, of surface AW, as well as to high July solar irradiance, within an area usually characterized by C. pelagicus-dominated low density populations.

  11. Feedbacks of sedimentation on crustal heat flow - New insights from the Vring Basin, Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Theissen, S.; Ruepke, L. H.

    2009-04-01

    Information on the nature and origin of rift basins is preserved in the presently observed stratigraphy. Basin modeling aims at recovering this information with the goal of quantifying a basin's structural and thermal evolution. Decompaction and backstripping analysis is a classic and still popular approach to basin reconstruction [Steckler and Watts, 1978]. The total and tectonic subsidences, as well as sedimentation rates are calculated by the consecutive decompaction and removal of individual layers. The thermal history has to be computed separately using forward thermal models. An alternative is coupled forward modeling, where the structural and thermal history is computed simultaneously. A key difference between these reconstruction methods is that feedbacks of sedimentation on crustal heat flow are often neglected in backstripping methods. In this work we use the coupled basin modeling approach presented by Rpke et al. [2008] to quantify some of the feedbacks between sedimentation and heat flow and to explore the differences between both reconstruction approaches in a case study from the Vring Basin, Norwegian Sea. In a series of synthetic model runs we have reviewed the effects of sedimentation on basement heat flow. These example calculations clearly confirm the well-known blanketing effect of sedimentation and show that it is largest for high sedimentation rates. Recovery of sedimentation rates from the stratigraphy is, however, not straightforward. Decompaction-based methods may systematically underestimate sedimentation rates as sediment thickness is assumed to not change/thin during stretching. We present a new method for computing sedimentation rates based on forward modeling and demonstrate the differences between both methods in terms of rates and thermal feedbacks in a reconstruction of the Vring basin (Euromargin transect 2). We find that sedimentation rates are systematically higher in forward models and heat flow is clearly depressed during times of high sedimentation. In addition, computed subsidence curves can differ significantly between backtripping and forward modeling methods. This shows that integrated basin modeling is important for improved reconstructions of sedimentary basins and passive margins. Rupke, L. H., et al. (2008), Automated thermotectonostratigraphic basin reconstruction: Viking Graben case study, AAPG Bulletin, 92(3), 309-326. Steckler, M. S., and A. B. Watts (1978), SUBSIDENCE OF ATLANTIC-TYPE CONTINENTAL-MARGIN OFF NEW-YORK, Earth and Planetary Science Letters, 41(1), 1-13.

  12. High precision {sup 230}Th and {sup 232}Th in the Norwegian Sea and Denmark by thermal ionization mass spectrometry

    SciTech Connect

    Moran, S.B.; Hoff, J.A.; Edwards, R.L.

    1995-10-01

    Seawater samples (1-2 liters) were collected from the Norwegian Sea and Denmark Strait and analyzed for {sup 230}Th and {sup 232}Th using highly sensitive thermal ionization mass spectrometry (TIMS). Depth profiles of dissolved {sup 230}Th and {sup 232}Th are characterized by surface water minima (<1 fg/kg, <5 pg/kg), subsurface maxima (12 fg/kg, 134 pg/kg), and intermediate concentrations that progressively decrease toward the bottom ({approximately}5 fg/kg, {approximately}17 pg/kg), respectively. The lack of an increase in {sup 230}Th with depth is suggested to result from the short ventilation age of Norwegian Sea Deep Water combined with enhanced scavenging near the basin margins. The {sup 230}Th maximum is attributed to advection of high {sup 230}Th in the Arctic Intermediate Water, whereas the {sup 232}Th maximum may he related to a particulate source. The low dissolved {sup 230}Th and {sup 232}Th concentrations observed in the NADW formation regions implies a minor advective export of these long-lived Th tracers to the North Atlantic. 24 refs., 1 fig., 1 tab.

  13. From conjugate volcanic rifted margins to micro-continent formation: Double breakup development of the Norwegian-Greenland Sea

    NASA Astrophysics Data System (ADS)

    Gernigon, Laurent; Blischke, Anett; Nasuti, Aziz; Olesen, Odleiv; Sand, Morten; Sveinn Arnarson, Thorarinn

    2014-05-01

    We re-evaluate the structure and spreading evolution of the Norwegian-Greenland Sea and surrounding volcanic (rifted) margins based on new high-resolution aeromagnetic surveys. The new dataset combined with long-offset seismic and gravity data allow us to have a better understanding of the structure and evolution of the conjugate margin systems in the Norwegian-Greenland Sea from the rifting to the drifting stage. We particularly focus on the new JAS-12 aeromagnetic survey acquired between the Aegir Ridge and the Jan Mayen micro-continent, which was initially part of the Mre-Vring-Greenland rift system. Combined with the previous NB-07 and JAS-05 surveys, our final compilation fully covers the continent-ocean transition and the whole oceanic spreading system from the Mre margin to the conjugate Jan Mayen micro-continent with high quality, high-resolution and reliable magnetic data. The new dataset allowed a new, consistent and precise interpretation of the magnetic polarity chrons and oceanic fractures, providing the basis for more accurate rotation poles estimation, and better basin and crustal reconstructions between Norway, Greenland and the Jan Mayen micro-continent. This dataset allowed us to clarify the pre- and post-breakup configurations of the rift system and discuss the mechanisms involved during the onset of the two phases of breakup leading to the micro-continent formation. Our observations and models suggest that the pre-breakup rift system evolved through a significant Late Jurassic-Cretaceous thinning phase. This episode led to a significant thinning of the continental crust and an exhumation of pre-existing lower crust. However, we have not been able to identify and/or validate any clear domains of exhumed and denudated serpentinised mantle. The first Eocene breakup is mostly characterised by severe magmatism (sill, SDRS). Lithospheric/asthenospheric processes leading to rift localisation do not necessarily represent a continuum of lithospheric deformation with the precedent thinning system. Diking and disconnected lithospheric plumbing are proposed to explain the Eocene breakup. After the first phase of continental breakup, two major phases of spreading influenced the Norwegian-Greenland Sea. Phase I (from C24 to C21r, ~54 to 49 Ma) marks the earliest phase of spreading, probably initiated in the central and outer part of the Mre Basin. During this period, the formation of overlapping systems and pseudo-fault development, indirectly influenced by the proto-margin segmentation, suggests the presence of additional micro-plates in the Norwegian-Greenland Sea. We also observed a significant change in the oceanic spreading system in the late Early Eocene. Based on observations from the surrounding areas, this supports a major and distinct tectonic and magmatic event in the Norwegian-Greenland Sea at around C21r (49-47.9 Ma), the beginning of a second phase. During Phase II, from C21r-C12 or possibly younger (48-<32 Ma) of the Norway Basin development, spreading rates decreased, spreading direction changed leading to the formation of unexpected N-S oriented oceanic fracture zones. Phase II probably coincides with the climax of extension and possibly local spreading that is suspected in the southern part of the Jan Mayen micro-continent forming a complex area of oceanic, transitional and continental fragments before its complete dislocation from East Greenland in Latest Oligocene.

  14. Integrated interpretation to improve subsalt imaging: a case study from the Nordkapp Basin, Norwegian Barents Sea

    NASA Astrophysics Data System (ADS)

    Olaf Müller, Christian; Brönner, Marco; Götze, Hans-Jürgen

    2015-04-01

    Seismic imaging of subsalt structures is still a difficult task and remaining uncertanties in the salt geometries makes exploration in the vicinity of such complex structures challenging. Gravity and magnetic data have proofed in the past their potential in combination with seismics to better delineate the shape of such salt structures. The current work deals with the improvement of subsalt imaging by combined interpretation of seismic and potential field data examined at a case study from the southern Nordkapp Basin. The Nordkapp Basin is a deep, narrow saliferous basin located in the southwestern Barents Sea. It comprises more than 30 salt diapirs, which are likely to create traps for hydrocarbons at their flanks and overhangs. Consequently exploration of the Nordkapp Basin with seismic methods started already in the 1980s, but until today solely seismics was not sufficient to reveal the nature and geometry for large parts of the basin. Therefore 2D and 3D seismic data were interpreted and used as stratigraphic constraints for the potential field modeling. For this purpose high resolution gravity and full tensor gravity gradient (FTG) data as well as a regional magnetic dataset were available. After processing the potential field data the 3D modeling was conducted by means of the interactive gravity and magnetic modeling software IGMAS+. Furthermore constraints for the rock properties, provided by well logs and susceptibility measurements of adjacent sedimentary well cores, were integrated. The favoured models indicate for both major salt structures a bulky base and a small root. The depth of the base of salt can vary in a range of about ± 300 m. Remaining mother salt is found in the northern part of the survey area and has no connection to the diapiric salt. Due to its higher sensibility to shallower sources the FTG data was used to model the flanks of the salt diapirs. In agreement with adjacent diapirs and encountered sequences a cap rock coverage was detected. Additionally, the gravity data and strong seismic reflections suggest a large impedance contrast and a high density body, consisting of dolomite-dominated carbonates and evaporites at the basin slope in the most southeastern corner of the Nordkapp Basin. In combination with the magnetic data the top of basement is located in 15 to 18 km depth. Furthermore a branch of an intrusion below Norsel High and intrusives in the centre of rift were detected. Our results proof the potential of integrated interpretation of seismic and potential field data. The modeling approach helps to overcome difficulties in seismic imaging of salt structures. Due to the sensibility to sources in different depths, especially FTG data and high resolution magnetic data increase the reliability of subsalt modelling. The resulting model provides additional information to improve seismic velocity models especially in the subsalt area. This study was carried out in the frame of a research project about joint inversion in cooperation with SINTEF, funded by the Norwegian research council, Det norske oljeselskap, Gaz de France and Eon Norge.

  15. Rock Physical study on an Upper-Palaeozoic Chert and Carbonate Interval in Wells from the Eastern Norwegian Barents Sea.

    NASA Astrophysics Data System (ADS)

    Colpaert, A.; Mienert, J.; Fotland, B.

    2004-12-01

    Due to their general interest as hydrocarbon reservoir, the Upper Palaeozoic chert and carbonate interval in the Norwegian Barents Sea has been investigated from seismic data and well logs. We established a framework for geophysical well log analysis and reservoir characterization for the Finnmark Platform, an area situated in the South-Eastern part of the Norwegian Barents Sea. The interval is composed by approximately 600 m carbonate facies covered by a 60 m interval of spiculitic chert facies. The carbonate facies is characterized by lateral and vertical lithological variations including limestones, dolomites, evaporites and clastic material. The spiculitic interval exists in spiculitic chert and clay alternated with limestones. Data extends over an area with different palaeo environments from inner platform settings to continental slope and even basinal settings. Log curve data from four wells were processed through geophysical well log analysis using Powerlog and Matlab. Multi-well trend analysis was performed for a diagnostic modeling of the rock physical parameters. The examination of the variation of petrophysical properties, and how that variation transfers into the elastic domain is a key to the correlation of rock properties and the seismic attribute information. The final goal is to improve porosity and mineralogy predictions in pseudo-wells from 3D seismic data. The analyses of cross plots allow distinguishing several intervals which in certain cases correspond to individual stratigraphic units. The spiculite interval shows for example different rock types based on rock physics and these parameters can be linked with seismic. For the synthetic seismogram an s-wave velocity log has been modeled. We observed that for several lithological intervals such as the mixed limestone-dolomites and spiculites the Greenberg-Castagna model fitted the best, but for pure dolomite intervals the Krief model is more accurate. Furthermore, for the purest limestone the best fit was obtained for the differential effective medium equations. These intervals should be treated differently for obtaining the best fitting velocity-porosity relations.

  16. Seasonal increase in sea temperature triggers pancreas disease outbreaks in Norwegian salmon farms.

    PubMed

    Stene, A; Bang Jensen, B; Knutsen, ; Olsen, A; Viljugrein, H

    2014-08-01

    Pancreas disease (PD) is a viral disease causing negative impacts on economy of salmon farms and fish welfare. Its transmission route is horizontal, and water transport by ocean currents is an important factor for transmission. In this study, the effect of temperature changes on PD dynamics in the field has been analysed for the first time. To identify the potential time of exposure to the virus causing PD, a hydrodynamic current model was used. A cohort of salmon was assumed to be infected the month it was exposed to virus from other infective cohorts by estimated water contact. The number of months from exposure to outbreak defined the incubation period, which was used in this investigation to explore the relationship between temperature changes and PD dynamics. The time of outbreak was identified by peak in mortality based on monthly records from active sites. Survival analysis demonstrated that cohorts exposed to virus at decreasing sea temperature had a significantly longer incubation period than cohorts infected when the sea temperature was increasing. Hydrodynamic models can provide information on the risk of being exposed to pathogens from neighbouring farms. With the knowledge of temperature-dependent outbreak probability, the farmers can emphasize prophylactic management, avoid stressful operations until the sea temperature is decreasing and consider removal of cohorts at risk, if possible. PMID:23980568

  17. Diet among oil-workers on off-shore oil installations in the Norwegian sector of the North Sea.

    PubMed

    Oshaug, A; Ostgård, L I; Trygg, K U

    1992-07-01

    Dietary studies based on 24 h recalls were carried out on four oil installations in the Norwegian sector of the North Sea. Two hundred and three persons were interviewed about what they had eaten the previous 24 h. Food purchased for the installations in the previous 5 months was recorded. Results based on 24 h recalls showed that average daily intake of energy was 12.2 MJ of which 17% came from protein, 44% from fat and 39% from carbohydrate, including 8% from sugar. Meat, vegetables, fresh fruits, seafood (shellfish), french fries, eggs, cream and ice-cream were important components of the diet, while bread, fish and cereals played a minor role. Average daily intake (mg) of nutrients were: calcium 1244, iron 15, vitamin A 1049 micrograms, vitamin D 4.1 micrograms, thiamin 1.6, riboflavin 2.2, nicotinic acid 22, ascorbic acid 143. Dietary fibre intake, estimated as unavailable carbohydrate, was on average 19 g, and the average daily intake of cholesterol was 755 mg. Intakes were compared with the Norwegian recommended dietary allowance. Most of the employees chose a diet which when eaten over a longer period of time may contribute to the development of coronary heart diseases (CHD) and thereby increase the morbidity and mortality from CHD in the oil industry. PMID:1390597

  18. Paleoenvironmental changes in the Norwegian Sea and the northeast Atlantic during the last 2.8 m.y.: Deep Sea Drilling Project/Ocean Drilling Program Sites 610, 642, 643 and 644

    NASA Astrophysics Data System (ADS)

    Jansen, E.; Bleil, U.; Henrich, R.; Kringstad, L.; Slettemark, B.

    1988-10-01

    Sedimentological, isotopic and magnetostratigraphic investigations of Ocean Drilling Program and Deep Sea Drilling Project sites 642, 643, 644 and 610 document the oceanographic and climatic evolution of the Norwegian Sea and the northeastern Atlantic over the last 2.8 m.y.. The results show that a major expansion of the Scandinavian Ice Sheet to the coastal areas took place at about 2.56 Ma. Relatively severe glacials appeared until about 2 Ma. The period 2.6 - 1.2 Ma experienced in general cold surface water conditions with only a weak influx of temperate Atlantic water as compared with late Quaternary interglacials. The Norwegian Sea was a sink of deep water through this period but deepwater ventilation was reduced and calcite dissolution was high compared with the Holocene. Deep water formed by other mechanisms than it does today. Between 2 and 1.2 Ma the glaciations in Scandinavia were small. A transition toward larger glacials took place during the period 1.2 to 0.6 Ma, corresponding to warmer interglacials and reduced calcite dissolution. Only during the last 0.6 m.y. has the oceanographic and climatic system of the Norwegian Sea varied in the manner described in previous studies of the late Quaternary. A strong thermal gradient was present between the Norwegian Sea and the northeastern Atlantic during the Matuyama (2.5-0.7 Ma). This is interpreted as a sign of a more zonal and less meridional climatic system over the region compared with the present situation.

  19. Satellite monitoring temperature conditions spawning area of the Northeast Arctic cod in the Norwegian Sea and assessment its abundance

    NASA Astrophysics Data System (ADS)

    Vanyushin, George; Bulatova, Tatiana; Klochkov, Dmitriy; Troshkov, Anatoliy; Kruzhalov, Michail

    2013-04-01

    In this study, the attempt to consider the relationship between sea surface anomalies of temperature (SST anomalies C) in spawning area of the Norwegian Arctic cod off the Lofoten islands in coastal zone of the Norwegian Sea and modern cod total stock biomass including forecasting assessment of future cod generation success. Continuous long-term database of the sea surface temperature (SST) was created on the NOAA satellites data. Mean monthly SST and SST anomalies are computed for the selected area on the basis of the weekly SST maps for the period of 1998-2012. These maps were plotted with the satellite SST data, as well as information of vessels, byoies and coastal stations. All data were classified by spawning seasons (March-April) and years. The results indicate that poor and low middle generations of cod (2001, 2006, 2007) occurred in years with negative or extremely high positive anomalies in the spawning area. The SST anomalies in years which were close to normal or some more normal significances provide conditions for appearance strong or very strong generations of cod (1998, 2000, 2002, 2004, 2005, 2006, 2008, 2009). Temperature conditions in concrete years influence on different indexes of cod directly. So, the mean temperature in spawning seasons in years 1999-2005 was ?5,0C and SST anomaly - +0,35C, by the way average year significances indexes of cod were: total stock biomass - 1425,0 th.t., total spawning biomass - 460,0 th.t., recruitment (age 3+) - 535,0 mln. units and landings - 530,0 th.t. In spawning seasons 2006-2012 years the average data were following: mean SST ?6,0C, SST anomaly - +1,29C, total stock biomass - 2185,0 th.t., total spawning biomass - 1211,0 th.t., recruitment (age 3+) - 821,0 mln. units and landings - 600,0 th.t. The SST and SST anomalies (the NOAA satellite data) characterize increase of decrease in input of warm Atlantic waters which form numerous eddies along the flows of the main warm currents thus creating favorable conditions for development of the cod larvae and fry and provide them with food stock, finally, direct influence on forming total stock biomass of cod and helping its population forecast. Key words: satellite monitoring of SST, Northeast Arctic cod, spawning area, maps of SST, prognosis.

  20. Infrasonic signatures of a Polar Low in the Norwegian and Barents Sea on 23 27 March 1992

    NASA Astrophysics Data System (ADS)

    Brre Orbk, Jon; Naustvik, Magnus

    1995-10-01

    This article presents an analysis of a Polar Low in the Norwegian and Barents Sea, 23 27 March 1992. The low is remote monitored from northern Norway and Svalbard by means of two Passive Broadband Infrasonic Sodars (PBIS's), estimating the directionality of the local acoustic field of atmospheric infrasound. The presented data show that the polar low apparently generates strong infrasound, and it is believed that some part of the measured pressure perturbations are generated by the intense turbulent regions of the low, as part of the aerodynamic spectrum. Due to the very low attenuation of infrasound in the atmosphere, the sound propagates to distant recording stations more than 1000km away, by successive reflections between the upper atmosphere and the sea surface. Because of the small number of synoptic stations in the area, data inputs to the numerical circulation models are few, and because the phenomena in study are mesoscale, down to one tenth the size of a frontal cyclone, conventional meteorological data may not resolve the features of interest. The infrasonic direction-of-arrival (DOA)-spectra produced by the PBIS passive acoustic remote sensing technique utilized in this work, is shown to give new information to the analysis of the weather situation. While the satellite images normally are ambiguous with respect to the dynamics and thermodynamic state of the visible cloud-clusters, the infrasonic DOA-spectra may provide valuable dynamic information of the distant polar low in near real time. It is suggested that the major part of the infrasonic signatures detected by the PBIS's come from the active regions of turbulent convection. By picking out the directions of these active intensification regions, the DOA-spectra may, as is shown in this article, indicate that several local disturbances took part in the complex polar low development.

  1. A baseline study of metals in herring (Clupea harengus) from the Norwegian Sea, with focus on mercury, cadmium, arsenic and lead.

    PubMed

    Frantzen, Sylvia; Maage, Amund; Duinker, Arne; Julshamn, Kaare; Iversen, Svein A

    2015-05-01

    The Norwegian spring spawning (NSS) herring is an ecologically and economically important fish population in the Norwegian Sea. It was the first of several Norwegian fish stocks subject to a baseline study designed to give a comprehensive account of the levels of contaminants in a fish species from most of its area of distribution and during different seasons. During 2006 and 2007, 800 individual herring were sampled in their feeding areas in the Norwegian Sea in spring and autumn and at their spawning grounds off the coast of Norway during late winter. Metals including Hg, Cd, As and Pb were determined in muscle samples of individual herring, and mean concentrationssd (mg kg(-1) ww) were: Hg: 0.040.03, Cd: 0.0100.006, As: 2.20.6 and Pb: <0.01-0.10. Apart from one sample, no individual herring exceeded the EU's maximum level for any of these elements, as has been seen also in previous monitoring. Hg and Cd concentration increased with increasing fish age and As concentration varied seasonally, possibly due to uptake during feeding (summer), elimination during starvation (winter) and up-concentration during spawning (spring). PMID:25703778

  2. Petroleum migration, alteration, and remigration within Troll field, Norwegian North Sea

    SciTech Connect

    Horstad, I.; Larter, S.R.

    1997-02-01

    Troll field represents the largest petroleum discovery within the entire North Sea area in oil equivalents, with 74% of the accumulated petroleum present as dry gas and 26% as a heavy biodegraded oil leg. The field is divided into several provinces based on the distribution of gas and oil, and the gas and oil have been suggested to be cogenetic. The migration and filling model presented in this paper suggests that the oil and gas represent two different migration phases and that gas migration and filling predate oil emplacement. Two different oil populations have been characterized and mapped in Troll field applying conventional geochemical techniques. We suggest that the two oil populations migrated into the structure through two different migration systems. Oil and gas were subsequently biodegraded within the reservoir. The two oil populations have been found in neighboring oil and gas discoveries, and an oil-oil correlation with these discoveries has been used to determine the location of field filling points and regional migration routes. When oil biodegradation terminated, fresh oil continued to migrate into the reservoir and mixed with the residue of the biodegraded oil. The field was tilted downward to the west in the Neogene, and oil and gas remigrated within the field with a possible spillage of gas. Tilting resulted in a dominantly upward movement of the oil phase whereas gas migrated laterally. Residual oils in the water zone have been used to reconstruct the paleoconfiguration of the field that controlled the current distribution of oil populations within Troll field.

  3. Barite and barium in sediments and coral skeletons around the hydrocarbon exploration drilling site in the Trna Deep, Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Lepland, Aivo; Mortensen, Pl Buhl

    2008-11-01

    Barite and barium concentrations in bottom sediments and coral skeletons from the vicinity of the hydrocarbon exploration well drilled in 1992 1993 in the Trna Deep, Norwegian Sea have been studied to assess the spreading of the drilling mud and related ecological effects on Lophelia petrusa coral reefs. Sand size barite crystals derived from the drilling mud and elevated Ba concentrations in surface (0 2 cm) sediments were found up to 4 km from the exploration drilling site. 210Pb-dating results on sediment cores indicate that Ba-rich surface intervals (0 2 cm) record ca. 20 years of sedimentation history, and connect Ba enrichment with exploration drilling. The geographic distribution of Ba contents in sediments allowed the reconstruction of the drilling mud dispersal pattern showing transport eastward from the drilling site, consistent with the prevailing current directions. The presence of relatively coarse-grained sediments and barite crystals trapped in coral polyps, ca. 500 m down current from the drilling site, reflects the elevated turbulence and sediment supply during the drilling activity. This elevated sediment dispersion likely placed a stress upon the coral reefs, but due to strong currents that effectively dilute episodic drilling waste and sediment discharges, the damage does not appear significant.

  4. Noise exposure of commercial divers in the Norwegian Sector of the North Sea.

    PubMed

    Nedwell, J R; Mason, T I; Collett, A G; Gardiner, R W K

    2015-01-01

    It is well known that exposure to high noise levels can adversely affect human hearing. Legislation exists in Europe to control or restrict the level of noise to which employees may be exposed during the course of their work. While the noise levels to which a worker may be exposed is well defined in air, human sensitivity to noise is different in high-pressure and mixed-gas conditions. Relatively little research exists to define human hearing in these circumstances, and few measurements exist of the levels of noise to which divers working in these conditions are exposed. A study using specially designed equipment has been undertaken in Norwegian waters to sample the noise levels present during typical saturation dives undertaken by commercial divers working in the Norwegian oil and gas industry. The divers were working in heliox at depths of 30 msw and 120 msw. It found noise levels were generally dominated by self-noise: flow noise while breathing and communications. The noise levels, both when corrected for the difference in hearing sensitivity under pressure in mixed gas and uncorrected, would exceed legislated limits for noise exposure in a working day without the use of noisy tools. PMID:26094290

  5. Fault growth and interactions in a multiphase rift fault network: Horda Platform, Norwegian North Sea

    NASA Astrophysics Data System (ADS)

    Duffy, Oliver B.; Bell, Rebecca E.; Jackson, Christopher A.-L.; Gawthorpe, Rob L.; Whipp, Paul S.

    2015-11-01

    Physical models predict that multiphase rifts that experience a change in extension direction between stretching phases will typically develop non-colinear normal fault sets. Furthermore, multiphase rifts will display a greater frequency and range of styles of fault interactions than single-phase rifts. Although these physical models have yielded useful information on the evolution of fault networks in map view, the true 3D geometry of the faults and associated interactions are poorly understood. Here, we use an integrated 3D seismic reflection and borehole dataset to examine a range of fault interactions that occur in a natural multiphase fault network in the northern Horda Platform, northern North Sea. In particular we aim to: i) determine the range of styles of fault interaction that occur between non-colinear faults; ii) examine the typical geometries and throw patterns associated with each of these different styles; and iii) highlight the differences between single-phase and multiphase rift fault networks. Our study focuses on a ca. 350km2 region around the >60km long, N-S-striking Tusse Fault, a normal fault system that was active in the Permian-Triassic and again in the Late Jurassic-to-Early Cretaceous. The Tusse Fault is one of a series of large (>1500m throw) N-S-striking faults forming part of the northern Horda Platform fault network, which includes numerous smaller (2-10km long), lower throw (<100m), predominantly NW-SE-striking faults that were only active during the Late Jurassic to Early Cretaceous. We examine how the 2nd-stage NW-SE-striking faults grew, interacted and linked with the N-S-striking Tusse Fault, documenting a range of interaction styles including mechanical and kinematic isolation, abutment, retardation and reactivated relays. Our results demonstrate that: i) isolated, and abutting interactions are the most common fault interaction styles in the northern Horda Platform; ii) pre-existing faults can act as sites of nucleation for 2nd-stage faults or may form mechanical barriers to propagation; iii) the throw distribution on reactivated 1st-stage faults will be modified in a predictable manner if they are intersected or influenced by 2nd-stage faults; iv) sites of fault linkage and relay-breaching associated with the first phase of extension can act as preferential nucleation sites for 2nd-stage faults; and v) the development of fault intersections is a dynamic process, involving the gradual transition from one style to another.

  6. Ichnofabric mapping and interpretation of Jurassic reservoir rocks of the Norwegian North Sea

    SciTech Connect

    Bockelie, J.F. )

    1991-06-01

    Recurrent sediment fabric and trace fossil associations in the Norwegian offshore Jurassic sequences have been interpreted by the ichnofabric concept. In the Sognefjord Formation (Oxfordian-Kimmeridgian) of the Troll Field five basic ichnofabrics were recognized and named after the dominant ichnogenus present, respectively: Helminthoida, Anconichnus, Palaeophycus, Ophiomorpha and Skolithos. These ichnofabrics developed in sediments deposited in marine environments ranging from quiescent offshore to high energy, shallow water nearshore situations. When sequence patterns of ichnofabrics were mapped within five chronostratigraphic reservoir zones of the Troll Field it was possible to recognize both how the frequency of a given ichnofabric may change in time in a restricted area or may change in its areal distribution in a restricted time interval. Such maps have been integrated with lithofacies maps and dip-meter studies in cored sequence to produce quantitative base maps for computerized reservoir models. The maps can also be used as a powerful tool for facies predictions.

  7. Summer distribution and ecological role of seabirds and marine mammals in the Norwegian and Greenland seas (June 1988)

    NASA Astrophysics Data System (ADS)

    Joiris, Claude R.

    1992-03-01

    During the ARK V /2 expedition of RV Polarstern in the Norwegian and Greenland seas in June 1988, 380 half hour counts for marine vertebrates (seabirds, pinnipeds and cetaceans) were carried out. Results are presented as total numbers encountered and then converted into density and food intake. Mean food intake was 2.2 kg fresh weight per km 2 per day for seabirds, with a higher value in Atlantic water (2.5) lower values in polar water and the pack ice (1.7 and 1.9), and an intermediate value at the ice edge. The main species were the alcids (1.5, primarily Little Auk, Alle alle and Brünnich's Guillemot, Urea Iomvia) ,the Fulmar, Fulmarus glacialis (0.5), and the Kittiwake, Rissa tridactyla (0.2). The ecological role of cetaceans was clearly lower, with a mean value of 0.2 and a maximum of 0.7 in Atlantic water (rough evaluation, due to the low number of contacts). The food intake by pinnipeds was 0.55 kg/km 2 day at the ice edge and 0.4 in the pack ice; they were mainly harp, Phoca groenlandica and hooded seals, Cystophora cristata, in one main concentration each and ringed seals, Phoca hispida, scattered on the pack. Data for July 1988 show a great similarity with these results, except for a lower density of alcids, which probably reflects that Little Auk, Brünnich's Guillemot and Common Guillemot, Uria aalge already had started to leave the region.

  8. Reconstruction and geochemical modelling of the diagenetic history of the middle Jurassic Oseberg sandstone reservoir, Oseberg Field, Norwegian North Sea

    SciTech Connect

    Girard, J.P.; Sanjuan, B.; Fouillac, C.

    1995-08-01

    A detailed multidisciplinary integrated study of the Middle Jurassic Oseberg reservoir in 13 wells of the Oseberg field, Norwegian North Sea, was carried out in order to (1) reconstruct precisely the timing, conditions and spatial variation of diagenetic transformations (2) characterize the nature and origin of the diagenetic fluids, and (3) develop a geochemical model of the observed diagenesis. The 20-60 in thick Oseberg Formation occurs at depths of 2.5 to 3.2 km, and at present temperatures ranging from 100 to 125{degrees}C. The detrital assemblage is mainly composed of quartz, K-feldspar, albrite, muscovite and lithic clay clasts, and is very homogeneous throughout the study area. The chronological sequence of diagenetic phases established from petrographic observations includes: minor siderite and pyrite, K-feldspar overgrowths, ankerite, feldspar dissolution, vermiform, kaolinite, quartz overgrowths, poikilotopic Fe-rich calcite, dickite. Diagenetic temperatures were determined from fluid inclusions in ankerite, quarts and calcite. Combination with modelled burial/thermal history permitted to constrain approximate ages and duration of major diagenetic events. Isotopic compositions of diagenetic cements indicate that meteoric water was (and still is) a major constituant of diagenetic fluids. Present formation waters are fairly similar chemically and isotopically at reservoir scale and represent mixing of three endmembers: seawater, meteoric water and primary evaporative brine. Stability diagrams and chemical geothermometers suggest that formation fluids are close to equilibrium with the host sandstone at present reservoir temperatures. Geochemical modelling of the diagenetic evolution of water-reservoir interactions was carried out using the EQ3/6 code and the Allan{sup TM}/Neptunix integrated simulator system. Results emphasize the importance of circulations of large volumes of fluid within the reservoir throughout the diagenetic history.

  9. A reservoir model for the Lower Cretaceous deep marine sandstones in the Maloy Fault Block area, Norwegian North Sea

    SciTech Connect

    Kloster, A.; Areklett, E.K.; Milton, N.

    1995-08-01

    The Maloy Fault Block area of the North Viking Graben forms a platform to the east of the Sogn Graben next to the coast of Norway. This area is characterized by an unusual and thick Lower Cretaceous section containing a number of discrete sandstone packages. Wells drilled elsewhere in the Norwegian North Sea are in contrast dominated by a relatively thin mud and marl dominated section in the Lower Cretaceous. Two wells in block 35/3 (the Agat field) encountered gas bearing sandstones of Albian age interpreted to represent deposition in a deep marine environment. An integrated sequence stratigraphic approach to the Lower Cretaceous stratigraphy in the Maloy Fault Block area has led to a new and more detailed understanding of controls on deposition in this area. This is based both on a regional dataset and good quality 3D seismic data. A Valanginian-Hauterivian relict slope/shelf system is present along the eastern basin margin. It formed a long-lasting topographic feature and in some areas was not onlapped until the Campanian time. A dramatic change in the basin configuration took place most likely in the Aptian time. This was initiated by erosion of the slope/shelf system which cut multiple huge canyons along the basin-margin. The canyons focused sediment input to the basin along discrete and mappable transport routes, some of which are controlled by erosion features inherited from the Late Jurassic. A complex history of deposition and filling followed. This was controlled by a constantly changing basin floor topography and left a complex pattern of partly constrained fan deposition.

  10. Reconstructing coastal environmental condition in the eastern Norwegian Sea by means of Arctica islandica sclerochronological records

    NASA Astrophysics Data System (ADS)

    Trofimova, Tamara; Andersson, Carin

    2015-04-01

    Paleo archives are fundament in improving our knowledge of the natural climate variability. Established marine proxy records for the ocean, especially for high latitudes, are both sparsely distributed and are poorly resolved in time. The identification and development of new archives and proxies for studying key ocean processes at annual to sub-annual resolution that can extend the marine instrumental record is therefore a clear priority for marine climate science. The bivalve species Arctica islandica is a unique paleoclimatic archive with an exceptional longevity combined with high temporal resolution, due to accretion of annual growth increments. The aim of this study is to use sclerochronological records of A. islandica to extend instrumental hydrographic records and increase our understanding of a variability of a Norwegian Coastal Current (NCC). The NCC transports warm, low-salinity water northwards, which eventually plays role for the Arctic halocline. Moreover, previous investigations showed the connection of properties and variability of the NCC with catches of commercially valuable fishes. The knowledge of the variability of the NCC is also essential for possible future prediction climate conditions and fish stock variability in the region. In this study we use shells of Arctica islandica collected off the coast of Eggum (Lofoten, Norway). The material was obtained from the depth 5-10 m by dredging along the seabed and by means of scuba divers. We examine the growth patterns of living and subfossil shells. Ongoing work mainly focuses on the construction of a composite growth chronology based on increment-width time series. The results we will compare with existing time series of the environment and climatic parameters to determine the controlling factors and test the applicability of growth chronology in a climate reconstruction. Furthermore, we will perform geochemical analyses of the stable isotope composition (δ18O and δ13C) in shell carbonate to identify seasonal signals and reconstruct the surface water temperature on a sub-annual time-scale.

  11. Geology of Barents Sea

    SciTech Connect

    Riis, F.; Vollset, J.

    1984-09-01

    The Barents Sea is situated on the continental shelf between Norway, the Spitsbergen Islands, and Novaya Zemlya. The main structural framework of the area was formed during the Caledonian and Hercynian orogenies, whereas the western parts were reactivated by the Kimmerian and Alpine orogenies. Because of the complex opening of the Greenland Norwegian Sea, important tertiary reactivation of Mesozoic normal faults occurred along southwest-northeast-trending systems of wrench faults. Owing to substantial erosion in the late Tertiary, the subsidence history and thermal development are more difficult to unravel in this area than in other places along the Norwegian Shelf. The erosion products were deposited in a huge sedimentary wedge extending onto the oceanic crust. The hydrocarbon discoveries in the Troms area in the southern part of the Barents Sea are encouraging for further exploration. However, the petroleum potential for large areas is not well known at this stage.

  12. Recovery of benthic megafauna from anthropogenic disturbance at a hydrocarbon drilling well (380 m depth in the Norwegian Sea).

    PubMed

    Gates, Andrew R; Jones, Daniel O B

    2012-01-01

    Recovery from disturbance in deep water is poorly understood, but as anthropogenic impacts increase in deeper water it is important to quantify the process. Exploratory hydrocarbon drilling causes physical disturbance, smothering the seabed near the well. Video transects obtained by remotely operated vehicles were used to assess the change in invertebrate megafaunal density and diversity caused by drilling a well at 380 m depth in the Norwegian Sea in 2006. Transects were carried out one day before drilling commenced and 27 days, 76 days, and three years later. A background survey, further from the well, was also carried out in 2009. Porifera (45% of observations) and Cnidaria (40%) dominated the megafauna. Porifera accounted for 94% of hard-substratum organisms and cnidarians (Pennatulacea) dominated on the soft sediment (78%). Twenty seven and 76 days after drilling commenced, drill cuttings were visible, extending over 100 m from the well. In this area there were low invertebrate megafaunal densities (0.08 and 0.10 individuals m(-2)) in comparison to pre-drill conditions (0.21 individuals m(-2)). Three years later the visible extent of the cuttings had reduced, reaching 60 m from the well. Within this area the megafaunal density (0.05 individuals m(-2)) was lower than pre-drill and reference transects (0.23 individuals m(-2)). There was a significant increase in total megafaunal invertebrate densities with both distance from drilling and time since drilling although no significant interaction. Beyond the visible disturbance there were similar megafaunal densities (0.14 individuals m(-2)) to pre-drilling and background surveys. Species richness, Shannon-Weiner diversity and multivariate techniques showed similar patterns to density. At this site the effects of exploratory drilling on megafaunal invertebrate density and diversity seem confined to the extent of the visible cuttings pile. However, elevated Barium concentration and reduced sediment grain size suggest persistence of disturbance for three years, with unclear consequences for other components of the benthic fauna. PMID:23056177

  13. Thermogenic degassing of methane during the PETM: Geochemical and palynological constrains from a borehole in the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Planke, Sverre; Svensen, Henrik; Frieling, Joost; Sluijs, Appy

    2015-04-01

    Emplacement of voluminous magmatic sills in sedimentary basins around the NE Atlantic led to widespread thermogenic gas generation in contact aureoles. Kilometer-sized degassing pipes and craters, termed hydrothermal vent complexes, are identified on seismic data and believed to have played a key role in releasing methane to the atmosphere and thus triggering of the Paleocene-Eocene Thermal Maximum (PETM). However, the link between pipe degassing and the PETM is questioned due to lack of accurate time constraints on degassing and crater formation. We present new geochemical and palynological data from a 3521 m deep petroleum exploration well, 6607/12-1, drilled through the center of a hydrothermal vent complex in the Vøring basin, the Norwegian Sea. We have undertaken a comprehensive sampling and analytical program of the cuttings from the well to study the age, formation and implications of the hydrothermal vent complex from this unique locality. Based on our results, we have divided the hydrothermal vent complex in four main zones: 1) a high temperature lower conduit (3521-2100 m), 2) an upper conduit (2100-1725 m), 3) crater deposits (1725-1590 m), and 4) seep carbonates (1510-1380 m). The crater is identified as a 2 km wide semi-circular eye-structure on the seismic data, characterized by low seismic velocities (Vp < 1.8 km/s) and high neutron porosities (>45%). The palynomorphs in the upper conduit have a high Thermal Alteration Index, suggesting heating from ascending fluids. At the base of the crater, the PETM dinocyst marker species Apectodinium augustum is present, thermally altered at the base but immature up-section. This can be explained by ejecta deposits at the base or by a final stage of hydrothermal activity. Carbon isotope analyses on palynomorph fractions shows that the PETM negative carbon isotope excursion (CIE) is present in the 1745-1665 m interval. The core of the PETM CIE is preserved at 1745-1720 m and the recovery stage from 1720-1665 m. The new data shows that the hydrothermal vent complex was formed during the early stage of the PETM and thus corroborates the hypothesis that continued thermogenic degassing was a key player in carbon cycle perturbations that characterize the PETM.

  14. Recovery of Benthic Megafauna from Anthropogenic Disturbance at a Hydrocarbon Drilling Well (380 m Depth in the Norwegian Sea)

    PubMed Central

    Gates, Andrew R.; Jones, Daniel O. B.

    2012-01-01

    Recovery from disturbance in deep water is poorly understood, but as anthropogenic impacts increase in deeper water it is important to quantify the process. Exploratory hydrocarbon drilling causes physical disturbance, smothering the seabed near the well. Video transects obtained by remotely operated vehicles were used to assess the change in invertebrate megafaunal density and diversity caused by drilling a well at 380 m depth in the Norwegian Sea in 2006. Transects were carried out one day before drilling commenced and 27 days, 76 days, and three years later. A background survey, further from the well, was also carried out in 2009. Porifera (45% of observations) and Cnidaria (40%) dominated the megafauna. Porifera accounted for 94% of hard-substratum organisms and cnidarians (Pennatulacea) dominated on the soft sediment (78%). Twenty seven and 76 days after drilling commenced, drill cuttings were visible, extending over 100 m from the well. In this area there were low invertebrate megafaunal densities (0.08 and 0.10 individuals m−2) in comparison to pre-drill conditions (0.21 individuals m−2). Three years later the visible extent of the cuttings had reduced, reaching 60 m from the well. Within this area the megafaunal density (0.05 individuals m−2) was lower than pre-drill and reference transects (0.23 individuals m−2). There was a significant increase in total megafaunal invertebrate densities with both distance from drilling and time since drilling although no significant interaction. Beyond the visible disturbance there were similar megafaunal densities (0.14 individuals m−2) to pre-drilling and background surveys. Species richness, Shannon-Weiner diversity and multivariate techniques showed similar patterns to density. At this site the effects of exploratory drilling on megafaunal invertebrate density and diversity seem confined to the extent of the visible cuttings pile. However, elevated Barium concentration and reduced sediment grain size suggest persistence of disturbance for three years, with unclear consequences for other components of the benthic fauna. PMID:23056177

  15. Environmental control of phytoplankton distribution and photosynthetic performance at the Jan Mayen Front in the Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Erga, Svein Rune; Ssebiyonga, Nicolausi; Hamre, Brge; Frette, yvind; Hovland, Erlend; Hancke, Kasper; Drinkwater, Kenneth; Rey, Francisco

    2014-02-01

    The Jan Mayen Front is located in the Norwegian Sea to the east of the Jan Mayen Ridge and separates warm, salty Atlantic water and colder, less salty Arctic water. The effects of the light regime, hydrographical conditions and nutrients on the variations of chlorophyll a (chl a), quantum efficiencies of photochemistry in PSII (Fv:Fm) and effective absorption cross-section of PSII (?PSII) at the Front were studied in June 2007. Stratified waters were seen on both sides of the Front and lowered nutrient concentrations were seen shallower than 10-20 m. The lowest values of the spectral diffuse attenuation coefficient, Kd (?), were found at 500-550 nm (0.07-0.16 m- 1), while Kd (465 nm) ranged between 0.08 and 0.17 m- 1 and Kd (380 nm) between 0.13 and 0.20 m- 1. Chl a concentrations seldom exceeded 1.0 mg m- 3 outside pure Atlantic Water, while elevated concentrations (3-4 mg m- 3) developed at depth (20-30 m) east of the Front in Atlantic Water. For the upper 100 m N/P, Si/P, N/Si and POC/PON ratios were 15.2, 8.0, 1.7 and 6.2, respectively. The quantum efficiency was strongly influenced by nutrients, suggesting nutrient limitation of phytoplankton biomass at the Front in June, but also light inhibition probably was a contributing factor in the upper part of the water column. High quantum efficiencies (0.5) and effective absorption cross sections (> 700 2 quanta- 1) were seen to the east of the Front and at depth (20-40 m) in stratified Atlantic waters. We therefore conclude that the Jan Mayen Front did not have a stimulatory effect on phytoplankton biomass enhancement and photosynthetic performance. This is in part due to the weak horizontal density front caused by density compensation of temperature and salinity characteristics of the adjacent water masses, and the associated weak vertical mixing.

  16. Deltamethrin resistance in the sea louse Caligus rogercresseyi (Boxhall and Bravo) in Chile: bioassay results and usage data for antiparasitic agents with references to Norwegian conditions.

    PubMed

    Helgesen, K O; Bravo, S; Sevatdal, S; Mendoza, J; Horsberg, T E

    2014-10-01

    The sea louse Caligus rogercresseyi is a major threat to Chilean salmonid farming. Pyrethroids have been used for anticaligus treatments since 2007, but have shown reduced effect, most likely due to resistance development. Pyrethroid resistance is also a known problem in Lepeophtheirus salmonis in the Northern Hemisphere. This study describes the development of deltamethrin resistance in C.rogercresseyi based on bioassays and usage data for pyrethroids in Chilean aquaculture. These results were compared to bioassays from L.salmonis from Norway and to Norwegian usage data. Available deltamethrin bioassay results from 2007 and 2008, as well as bioassays from Norway, were collected and remodelled. Bioassays were performed on field-collected sea lice in region X in Chile in 2012 and 2013. Bioassays from 2007 were performed prior to the introduction of pyrethroids to the Chilean market. Both the results from 2008 and 2012 showed an increased resistance. Increased pyrethroid resistance was also indicated by the increased use of pyrethroids in Chilean aquaculture compared with the production of salmonids. A similar trend was seen in the Norwegian usage data. The bioassay results from Chile from 2012 and 2013 also indicated a difference in the susceptibility to deltamethrin between male and female caligus. PMID:24697556

  17. Arctic Sea Level Since 1950

    NASA Astrophysics Data System (ADS)

    Cazenave, A. A.; Henry, O.; Prandi, P.; Llovel, W.; Jevrejeva, S.

    2011-12-01

    We investigate sea level change and variability in the Arctic region over the 1950-2009 time span. Analysis of >60 long tide gauge records available since 1950 along the Norwegian and Russian sectors shows that coastal mean sea level was almost stable until about 1980 but since then displayed a clear increasing trend. In fact until the mid-1990s, the mean sea level closely followed the Arctic Oscillation (AO) index variations. However, since about 1995, the mea sea level curve departs from the AO influence and presents a large increasing trend of ~ 4 mm/yr. Using in situ ocean temperature data down to 700 m (from the WOD09 and JAMSTEC data bases), we estimated the thermosteric sea level at the tide gauge sites of the Norwegian sector and found that the recent increase in sea level has a dominant thermal origin. This suggests that inflow of warm North Atlantic waters may be responsible for the recent sea level changes observed along the Norwegian and Russian coasts. Comparison, over the altimetry era (since 1993), of altimetry-based and steric spatial trend patterns in sea level in the North Atlantic (>50N) and Nordic Seas shows on the other hand that observed (altimetry-based) patterns essentially result from a combination of temperature and salinity effects, themselves driven by natural climate modes (AO and NAO).

  18. Radioactive contamination from dumped nuclear waste in the Kara Sea--results from the joint Russian-Norwegian expeditions in 1992-1994.

    PubMed

    Salbu, B; Nikitin, A I; Strand, P; Christensen, G C; Chumichev, V B; Lind, B; Fjelldal, H; Bergan, T D; Rudjord, A L; Sickel, M; Valetova, N K; Fyn, L

    1997-08-25

    Russian-Norwegian expeditions to the Kara Sea and to dumping sites in the fjords of Novaya Zemlya have taken place annually since 1992. In the fjords, dumped objects were localised with sonar and ROV equipped with underwater camera. Enhanced levels of 137Cs, 60Co, 90Sr and 239,240Pu in sediments close to dumped containers in the Abrosimov and Stepovogo fjords demonstrated that leaching from dumped material has taken place. The contamination was inhomogeneously distributed and radioactive particles were identified in the upper 10 cm of the sediments. 137Cs was strongly associated with sediments, while 90Sr was more mobile. The contamination was less pronounced in the areas where objects presumed to be reactor compartments were located. The enhanced level of radionuclides observed in sediments close to the submarine in Stepovogo fjord in 1993 could, however, not be confirmed in 1994. Otherwise, traces of 60Co in sediments were observed in the close vicinity of all localised objects. Thus, the general level of radionuclides in waters, sediments and biota in the fjords is, somewhat higher or similar to that of the open Kara Sea, i.e. significantly lower than in other adjacent marine systems (e.g. Irish Sea, Baltic Sea, North Sea). The main sources contributing to radioactive contamination were global fallout from atmospheric nuclear weapon tests, river transport from Ob and Yenisey, marine transport of discharges from Sellafield, UK and fallout from Chernobyl. Thus, the radiological impact to man and the arctic environment of the observed leakages from dumped radioactive waste today, is considered to be low. Assuming all radionuclides are released from the waste, preliminary assessments indicate a collective dose to the world population of less than 50 man Sv. PMID:9241886

  19. Quantifying the Ocean, Freshwater and Human Effects on Year-to-Year Variability of One-Sea-Winter Atlantic Salmon Angled in Multiple Norwegian Rivers

    PubMed Central

    Otero, Jaime; Jensen, Arne J.; L'Abe-Lund, Jan Henning; Stenseth, Nils Chr.; Storvik, Geir O.; Vllestad, Leif Asbjrn

    2011-01-01

    Many Atlantic salmon, Salmo salar, populations are decreasing throughout the species' distributional range probably due to several factors acting in concert. A number of studies have documented the influence of freshwater and ocean conditions, climate variability and human impacts resulting from impoundment and aquaculture. However, most previous research has focused on analyzing single or only a few populations, and quantified isolated effects rather than handling multiple factors in conjunction. By using a multi-river mixed-effects model we estimated the effects of oceanic and river conditions, as well as human impacts, on year-to-year and between-river variability across 60 time series of recreational catch of one-sea-winter salmon (grilse) from Norwegian rivers over 29 years (19792007). Warm coastal temperatures at the time of smolt entrance into the sea and increased water discharge during upstream migration of mature fish were associated with higher rod catches of grilse. When hydropower stations were present in the course of the river systems the strength of the relationship with runoff was reduced. Catches of grilse in the river increased significantly following the reduction of the harvesting of this life-stage at sea. However, an average decreasing temporal trend was still detected and appeared to be stronger in the presence of salmon farms on the migration route of smolts in coastal/fjord areas. These results suggest that both ocean and freshwater conditions in conjunction with various human impacts contribute to shape interannual fluctuations and between-river variability of wild Atlantic salmon in Norwegian rivers. Current global change altering coastal temperature and water flow patterns might have implications for future grilse catches, moreover, positioning of aquaculture facilities as well as the implementation of hydropower schemes or other encroachments should be made with care when implementing management actions and searching for solutions to conserve this species. PMID:21897867

  20. Effects of bottom water warming and sea level rise on Holocene hydrate dissociation and mass wasting along the Norwegian-Barents Continental Margin

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Yeol; Vogt, Peter R.

    2004-06-01

    Gas hydrate (GH) stability modeling results explain why some major Holocene submarine landslides along the Norwegian-Barents margin could have been triggered by GH dissociation during the early to middle Holocene, not during the lowest sea levels of the Last Glacial Maximum (LGM). Our model results show that subbottom depths of 170-260 m below the pre-slide continental slope (ca. 350-475 m present water depth) must have passed out of gas hydrate stability zone (GHSZ) by 8.15 ka as the effect of warm bottom water inflow at 11 ka penetrated into the subbottom, overcoming the effects of pressure increase due to sea level rise (SLR). The component of local SLR due to the isostatic response to Fennoscandian deglaciation is shown to be relatively insignificant, particularly for the part of the upper continental slope where the slide probably began. The stability relations show that GH could have formed under the ice sheet before deglaciation, and below deeper shelf areas after sea levels began to rise, but before significant warming near the GHSZ base. To the extent water deeper than 800 m has remained cold (-1 to 0C) since LGM times, the GHSZ continued to thicken in deep water and GH dissociation could not have triggered Holocene failure in that regime. The present distribution of GH stability is limited to water depths greater than about 400 m in the Storegga slide area, and the thickness of the GHSZ increases with water depth.

  1. Aral Sea

    Atmospheric Science Data Center

    2013-04-16

    ... the fourth-largest inland sea in the world. Since then, its water volume has dropped by about 80% due to extensive irrigation systems ... Sea has led to soil and water salination and agrochemical contamination. The retreating shoreline leaves the surface encrusted with salt ...

  2. Extreme hydrogen, oxygen and carbon isotope anomalies in the pore waters and carbonates of the sediments and basalts from the Norwegian Sea: Methane and hydrogen from the mantle

    SciTech Connect

    Lawrence, J.R. ); Taviani, M. )

    1988-08-01

    D/H ratios in the pore waters of the sediments from the Norwegian Sea decrease as a function of depth to values as low as {minus}14{per thousand}. Oxygen isotope ratios in the pore waters and carbon and oxygen isotope ratios in carbonates both in the sediments and basalts are low. Extensive alteration of basalt has been given as the explanation for the low oxygen isotope ratios. Material balance calculations suggest that alteration of volcanic material and oxidation of organic matter cannot explain the hydrogen and carbon isotope anomalies. Arguments are presented suggesting that methane and hydrogen from the mantle are oxidized to carbon dioxide and water by sulfate and ferric iron in the basaltic crust to yield the low hydrogen and carbon isotope ratios.

  3. A cold air outbreak over the Norwegian Sea observed with the Tiros-N Operational Vertical Sounder (TOVS) and the Special Sensor Microwave/Imager (SSM/I)

    NASA Technical Reports Server (NTRS)

    Claud, Chantal; Katsaros, Kristina B.; Petty, Grant W.; Chedin, Alain; Scott, Noelle A.

    1992-01-01

    Until recently, the scarcity of meteorological observations over polar areas has limited studies of high latitude weather systems, but now data from polar orbiting satellites offer a new opportunity to observe and describe these systems. TOVS data were used successfully for delineating synoptic and subsynoptic systems since they provide the vertical temperature structure of the atmosphere: SSM/I observations have proved valuable for analyzing storms through water vapor and rain determinations. These positive results prompted us to analyze simultaneous TOVS and SSM/I observations obtained during a cold air outbreak over the Norwegian Sea. After a description of the instruments and the retrieval schemes, the mutually supporting information from these two independent instruments is discussed. Implications for the monitoring of polar lows are presented.

  4. A cold air outbreak over the Norwegian Sea observed with the Tiros-N Operational Vertical Sounder (TOVS) and the Special Sensor Microwave/Imager (SSM/I)

    NASA Technical Reports Server (NTRS)

    Claud, Chantal; Katsaros, Kristina B.; Petty, Grant W.; Chedin, Alain; Scott, Noelle A.

    1992-01-01

    Until recently, the scarcity of meteorological observations over polar areas has limited studies of high-latitude weather systems, but now data from polar orbiting satellites offer a new opportunity to observe and describe these systems. TOVS data have been used successfully for delineating synoptic and subsynoptic systems, since they provide the vertical temperature structure of the atmosphere; SSM/I observations have proved valuable for analyzing storms through water vapor and rain determinations. These positive results prompted simultaneous analysis of TOVS and SSM/I observations obtained during a cold air outbreak over the Norwegian Sea. After a description of the instruments and the retrieval schemes, the mutually supporting information from these two independent instruments is discussed. Implications for the monitoring of polar lows are presented.

  5. Analysis of CO2 trapping capacities and long-term migration for geological formations in the Norwegian North Sea using MRST-co2lab

    NASA Astrophysics Data System (ADS)

    Mll Nilsen, Halvor; Lie, Knut-Andreas; Andersen, Odd

    2015-06-01

    MRST-co2lab is a collection of open-source computational tools for modeling large-scale and long-time migration of CO2 in conductive aquifers, combining ideas from basin modeling, computational geometry, hydrology, and reservoir simulation. Herein, we employ the methods of MRST-co2lab to study long-term CO2 storage on the scale of hundreds of megatonnes. We consider public data sets of two aquifers from the Norwegian North Sea and use geometrical methods for identifying structural traps, percolation-type methods for identifying potential spill paths, and vertical-equilibrium methods for efficient simulation of structural, residual, and solubility trapping in a thousand-year perspective. In particular, we investigate how data resolution affects estimates of storage capacity and discuss workflows for identifying good injection sites and optimizing injection strategies.

  6. Ross Sea

    Atmospheric Science Data Center

    2013-04-16

    ... (3794 meters). It overlooks McMurdo Station, a U.S. research facility located near the tip of the island's Hut Point Peninsula. MISR was ... 2000 Images:  Ross Sea location:  Antarctica thumbnail:  ...

  7. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    ... and is surrounded by hot, dry deserts and steppes. More fish species (over 1000) live in the Red Sea than in any other body of water the same size. Data: August 13, 2000; MISR Level 1B2 Ellipsoid ...

  8. Arabian Sea

    Atmospheric Science Data Center

    2013-04-16

    ... sometimes results in copious phytoplankton production and oxygen depletion of the subsurface waters. Although red phytoplankton fluorescences have been associated with the low oxygen concentrations in the intermediate and deep waters of the Arabian Sea, ...

  9. Sea Legs

    NASA Astrophysics Data System (ADS)

    Macdonald, Kenneth C.

    Forty-foot, storm-swept seas, Spitzbergen polar bears roaming vast expanses of Arctic ice, furtive exchanges of forbidden manuscripts in Cold War Moscow, the New York city fashion scene, diving in mini-subs to the sea floor hot srings, life with the astronauts, romance and heartbreak, and invading the last bastions of male exclusivity: all are present in this fast-moving, non-fiction account of one woman' fascinating adventures in the world of marine geology and oceanography.

  10. Satellite observations of a polar low over the Norwegian Sea by Special Sensor Microwave Imager, Geosat, and TIROS-N Operational Vertical Sounder

    NASA Technical Reports Server (NTRS)

    Claud, Chantal; Mognard, Nelly M.; Katsaros, Kristina B.; Chedin, Alain; Scott, Noelle A.

    1993-01-01

    Many polar lows are generated at the boundary between sea ice and the ocean, in regions of large temperature gradients, where in situ observations are rare or nonexistent. Since satellite observations are frequent in high-latitude regions, they can be used to detect polar lows and track their propagation and evolution. The Special Sensor Microwave/Imager (SSM/I) providing estimates of surface wind speed, integrated cloud liquid water content, water vapor content, and precipitation size ice-scattering signal over the ocean; the Geosat radar altimeter measuring surface wind speed and significant wave height; and the TIROS-N Operational Vertical Sounder (TOVS) allowing the determination of temperature and humidity profiles in the atmosphere have been used in synergy for a specific case which occurred in the Norwegian Sea on January, 23-24 1988. All three instruments show sharp atmospheric gradients associated with the propagation of this low across the ocean, which permit the detection of the polar low at a very early stage and tracking it during its development, propagation, and decay. The wind speed gradients are measured with good qualitative agreement between the altimeter and SSM/I. TOVS retrieved fields prior to the formation of the low confirm the presence of an upper level trough, while during the mature phase baroclinicity can be observed in the 1000-500 hPa geopotential thicknesses.

  11. Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This series of MODIS images shows the dwindling Aral Sea. Once one of the world's largest freshwater lakes, the Aral Sea has decreased by as much as 60% over the past few decades due to diversion of the water to grow cotton and rice. These diversion have dropped the lake levels, increased salinity, and nearly decimated the fishing industry. The previous extent of the lake is clearly visible as a whitish perimeter in these image from April 16, May 18, and June 3, 2002. s. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  12. Sea Ice

    NASA Technical Reports Server (NTRS)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  13. Sea ice in the China Sea

    SciTech Connect

    Deng Shuqi

    1993-12-31

    In every winter, sea ice occurring in Bohai Sea and the North Yellow Sea is the first-year ice which is going through generating, developing and thawing processes. Therefore, it is necessary to spatially and temporally describe ice period, freezing range, thickness variations and general motion of sea ice. The purpose of this paper is to provide initial general situation and features of sea ice for forecasting and researching sea ice.

  14. No slowdown yet for busy North Sea

    SciTech Connect

    McNally, R

    1989-08-01

    This article reports on oil and gas operations in the North Sea. Current offshore licensing rounds for both the United Kingdom and Norwegian sides are described. Developmental projects are detailed, including the installation of a tank barrier to protect a Norwegian drilling complex from seafloor subsidence. Dutch and Danish exploration is also discussed.

  15. From Sea to Shining Sea

    ERIC Educational Resources Information Center

    Scott, Beverly

    2005-01-01

    Deep down in the depths of the sea, beautiful fish, mysterious ocean life, and unusual plants glimmer and glow in the eerie atmosphere of an ever-changing ocean. This article describes how, with this vision and a purpose in mind, three teachers pulled open classroom walls and joined forces so their second graders could create a mammoth 30 x 75"…

  16. From Sea to Shining Sea

    ERIC Educational Resources Information Center

    Scott, Beverly

    2005-01-01

    Deep down in the depths of the sea, beautiful fish, mysterious ocean life, and unusual plants glimmer and glow in the eerie atmosphere of an ever-changing ocean. This article describes how, with this vision and a purpose in mind, three teachers pulled open classroom walls and joined forces so their second graders could create a mammoth 30 x 75"

  17. Latitudinal fractionation of polychlorinated biphenyls in surface seawater along a 62 degrees N-89 degrees N transect from the southern Norwegian Sea to the North Pole area.

    PubMed

    Sobek, Anna; Gustafsson, Orjan

    2004-05-15

    Surface seawater concentrations of PCBs, relative congener abundance, and possible effects of cold condensation were studied along a transect from the southern Norwegian Sea to the central Arctic Ocean (62 degrees N-89 degrees N). Large volume samples were collected from an ice breaker using a stainless steel surface seawater intake connected online to an ultra-clean laboratory. Concentrations of all studied PCB congeners, except for trichlorinated PCB 18, decreased with latitude. For instance, PCB 52 decreased from 470 fg L(-1) at 62 degrees N to 110 fg L(-1) at 89 degrees N and PCB 180 from 110 to 12 fg L(-1). Concentrations in the central Arctic Ocean were on the order of 10-100 fg L(-1) for the most abundant congeners. The relative contribution oftrichlorinated PCBs to the total PCB concentration increased with latitude, the tetrachlorinated contribution to the total PCBs did not show any correlation to latitude, and the relative contribution of heavier congeners decreased with latitude. This study establishes the occurrence at very low abundances of PCBs in seawater in the central Arctic Ocean and demonstrates a northward concentration decrease. The latitudinal shift in congener pattern is reflecting the relative propensity of the PCB congeners to undergo long-range transport in the Arctic and is consistent with their relative vapor pressures. PMID:15212246

  18. Coccolithophore community composition and calcification rates in the Norwegian and Greenland seas as a function of carbonate chemistry and other environmental parameters.

    NASA Astrophysics Data System (ADS)

    Loucaides, S.; Poulton, A.; Bellerby, R.; Tyrrell, T.

    2012-04-01

    The industrial revolution and the subsequent increase in fossil fuel combustion has led to a dramatic increase of carbon dioxide (CO2) released into the atmosphere. About a quarter of the anthropogenic CO2 released during the last few decades has been taken up by the ocean leading to a decrease in pH and CaCO3 saturation states (?). CaCO3 saturation states are lower in high latitude waters mainly due to the fact that cold water can hold more CO2 and that dissolved CO2 in most of the surface ocean is at near-equilibrium with the atmosphere. Current projections suggest that increasing uptake of CO2, combined with higher freshwater inputs from ice melt will lead to the entire water column of the arctic to become undersaturated with respect to aragonite by the end of this century. Although the effect of ocean acidification on marine calcifiers remains unclear, studies suggest that lower saturation states will have adverse consequences on several groups of calcifying organisms including some coccolithophore species. Coccolithophores play a major role in the ocean carbon cycle by contributing to both the biological and carbonate pumps. They are most prominent in high latitude waters although very little is known about what controls their distribution and abundance. The main goal of this study was to collect coccolithophore diversity, abundance and calcification rate data along transects of strong environmental and carbonate chemistry gradients. Here we present data collected in June 2009 along several transects between Norway, Greenland and Svalbard. Coccolithophore abundance, diversity and calcification rates were measured and compared with macronutrients, salinity, temperature, and carbonate chemistry parameters (i.e. TA, DIC, pH, pCO2 and ?). The strongest temperature gradients were observed along latitudinal transects with minimum SST values along the Greenland ice edge (T = 0-1 C) and maximum values along the north Norwegian coast and the south-western coast of Spitsbergen Island (T = 5-8 C). Surface salinity values were affected mainly by terrestrial freshwater inputs from Norway and Spitsbergen Island and ice melt along the Greenland ice edge. Saturation states of calcite and aragonite were highest along the eastern part of the study area (?cal = 3.4-3.9 ; ?arag = 2.1-2.5) and lowest along the Greenland ice edge (?cal = 2.9-3.3 ; ?arag = 1.8-2.1). Eleven coccolithophore species were identified during the cruise with Emiliania huxleyi and Calciopappus caudatus being the most abundant. Coccolithophore abundance, diversity and calcification rates decreased from southeast (Norwegian coast) northward (Spitsbergen) and westward (Greenland). Coccolithophores were nearly absent in the Greenland Sea with the exception of a small number of Coccolithus pelagicus. Multivariate analysis suggests that both temperature and carbonate chemistry are at least partly responsible for the distribution and abundance of coccolithophores in the Greenland and Norwegian Seas.

  19. Climate variability and long-term expansion of peat lands in Arctic Norway during the late Pliocene (ODP Site 642, Norwegian Sea)

    NASA Astrophysics Data System (ADS)

    Panitz, S.; Salzmann, U.; Risebrobakken, B.; De Schepper, S.; Pound, M. J.

    2015-12-01

    Little is known about the terrestrial response of high latitude Scandinavian vegetation to the warmer-than-present climate of the Late Pliocene (Piacenzian, 3.60-2.58 Ma). In order to assess Piacenzian terrestrial climate variability we present the first high resolution reconstruction of vegetation and climate change in northern Norway between 3.6-3.14 Ma. The reconstructions are derived from pollen assemblages in the marine sediments of ODP Hole 642B, Norwegian Sea (67° N). The palynological assemblages provide a unique record of latitudinal and altitudinal shifting of the forest boundaries, with vegetation alternating between cool temperate forest during warmer-than-present intervals, and boreal forest similar to today during cooler intervals. The northern boundary of the nemoral to boreonemoral forest zone was displaced at least 4-8° further north and warmest month temperatures were 6-14.5 °C higher than present during warm phases. Warm climatic conditions persisted during the earliest Piacenzian (ca. 3.6-3.47 Ma) with diverse cool temperate nemoral to boreonemoral forests growing in the lowlands of the Scandinavian mountains. A distinct cooling event at ca. 3.47 Ma resulted in a southward shift of vegetation boundaries, leading to the predominance of boreal forest and the development of open, low alpine environments. The cooling culminated around 3.3 Ma, coinciding with Marine Oxygen Isotope Stage (MIS) M2. Warmer climate conditions returned after ca. 3.29 Ma with higher climate variability indicated by the repeated expansion of forests and peat lands during warmer and cooler periods, respectively. Climate progressively cooled after 3.18 Ma, resembling climatic conditions during MIS M2. A high variability of Norwegian vegetation and climate changes during the Piacenzian is superimposed on a long-term cooling trend. This cooling was accompanied by an expansion of Sphagnum peat lands that potentially contributed to the decline in atmospheric CO2-concentrations at the end of the Piacenzian warm period and facilitated ice growth through positive vegetation-snow albedo feedbacks. Correlations with other Northern Hemisphere vegetation records suggest hemisphere-wide effects of climate cooling.

  20. A Marine Controlled-Source Electromagnetic Study for the Characterization of Methane Hydrate and Free Gas Reservoirs at the Nyegga CNE03 Pockmark, Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Attias, E.; Weitemeyer, K.; Sinha, M. C.; Minshull, T. A.; Jegen, M. D.; Berndt, C.

    2014-12-01

    In recent years, gas hydrate deposits have attracted growing interest from both academic and industry research, due to their potential as an unconventional energy resource, role in climate change and concern as a geohazard to various marine infrastructures. Methane hydrates are known to accommodate widespread regions of sea sediments at depths ranging from 130 to 2,000 m along offshore continental margins, normally located close to the seafloor and often presenting pockmarks that are underlain by chimney-like structures. The Nyegga region is situated along the west Norwegian continental slope and characterized by an extensive pockmark field. The Nyegga pockmarks are manifested by bathymetric troughs, seep-associated organisms, and rich methane-derived authigenic carbonate rocks. A controlled-source electromagnetic (CSEM) survey was performed along Nyegga CNE03 Pockmark, where high-resolution 3D seismic data was previously collected and analyzed. The aim of this CSEM study is to characterize the hydrate and free gas distribution along the CNE03 pockmark region. 2D CSEM inversions and pseudosections were computed using the data acquired by ocean bottom electrical field receivers (OBE) and the 3-axis towed receiver (Vulcan), respectively. Initial results from both data sets, confirm the existence of a subtle though distinctive resistivity anomaly structure at the CNE03 pockmark, suggesting a shallow anomaly at the chimney center, likely to result from the presence of gas hydrate. Furthermore, a deeper and latterly extensive resistivity anomaly emerged from the 2D inversions, most probably attributed to the existence of a free gas layer beneath the base of the gas hydrate stability zone (BGHSZ). This work will contribute to accurately estimate the amount of methane hydrate and free gas both at the pockmark level and over a larger regional scale, providing valuable information in light of the fact that there are more than 220 known gas hydrate deposits worldwide.

  1. Sea Ice

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Cavalieri, Donald J.

    2005-01-01

    Sea ice covers vast areas of the polar oceans, with ice extent in the Northern Hemisphere ranging from approximately 7 x 10(exp 6) sq km in September to approximately 15 x 10(exp 6) sq km in March and ice extent in the Southern Hemisphere ranging from approximately 3 x 10(exp 6) sq km in February to approximately 18 x 10(exp 6) sq km in September. These ice covers have major impacts on the atmosphere, oceans, and ecosystems of the polar regions, and so as changes occur in them there are potential widespread consequences. Satellite data reveal considerable interannual variability in both polar sea ice covers, and many studies suggest possible connections between the ice and various oscillations within the climate system, such as the Arctic Oscillation, North Atlantic Oscillation, and Antarctic Oscillation, or Southern Annular Mode. Nonetheless, statistically significant long-term trends are also apparent, including overall trends of decreased ice coverage in the Arctic and increased ice coverage in the Antarctic from late 1978 through the end of 2003, with the Antarctic ice increases following marked decreases in the Antarctic ice during the 1970s. For a detailed picture of the seasonally varying ice cover at the start of the 21st century, this chapter includes ice concentration maps for each month of 2001 for both the Arctic and the Antarctic, as well as an overview of what the satellite record has revealed about the two polar ice covers from the 1970s through 2003.

  2. Mammals of the Sea.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  3. Tracking Sea Otters

    USGS Multimedia Gallery

    USGS sea otter researcher Tim Tinker drives the boat on an expedition to track and observe sea otters in Monterey Bay, California. USGS scientists study sea otters in efforts to help the threatened species continue to recover from near extinction....

  4. Studying Sea Otters

    USGS Multimedia Gallery

    Sea otter researcher Michelle Staedler, of the Monterey Bay Aquarium, records sea otter behavior in her logbook as part of a study with the USGS and the University of California at Santa Cruz on sea otter behavior. ...

  5. Extensional tectonics, halokinesis, eustacy in the Norwegian Central Graben, North Sea: A testing ground for sequence and seismic stratigraphic principles

    SciTech Connect

    Spencer, P.A.; Prosser, S.D.

    1996-12-31

    The Norwegian Central Graben is a mature hydrocarbon province with proven reserves within the Upper Jurassic succession. Several phases of extensional tectonics ranging from the Permo-Triassic to the Upper Jurassic, and a thick mobile salt section, serve to complicate a clear regional understanding of the area. A full integration of structural interpretation, seismic and sequence stratigraphic principles, biostratigraphy and core studies is required to achieve a realistic interpretation and predict Upper Jurassic facies distributions within this complex area. Utilizing some 30 wells, regional seismic data and biostratigraphy, candidate sequence boundaries and regionally correlatable flooding surfaces (e.g. Eudoxus), have been identified. Horizon flattening on these surfaces has allowed the recognition of thickening-away reflection geometries adjacent to salt features and divergent geometries into graben boundary faults. This facilitates the identification of the dominant local or regional controls on accommodation space creation. Detailed seismic facies analysis was then used to reveal the relative expansion or suppression of depositional systems tracts as a response to either regional or local structural controls. It was subsequently possible to place these systems within a biostratigraphically constrained regional framework. Mapping the base Zechstein, base Jurassic and base Cretaceous horizons has provided a map view of the active faults and slopes controlling sediment transport at any given time. This provided the third dimension essential in depicting the spatial distribution of depositional systems, and is a crucial component of any sequence stratigraphic interpretation. A regional picture of the progressive evolution of this complex area has been thus been derived, and the effect of both regional and local controls on sequence stratigraphic expressions has been determined.

  6. Extensional tectonics, halokinesis, eustacy in the Norwegian Central Graben, North Sea: A testing ground for sequence and seismic stratigraphic principles

    SciTech Connect

    Spencer, P.A. ); Prosser, S.D. )

    1996-01-01

    The Norwegian Central Graben is a mature hydrocarbon province with proven reserves within the Upper Jurassic succession. Several phases of extensional tectonics ranging from the Permo-Triassic to the Upper Jurassic, and a thick mobile salt section, serve to complicate a clear regional understanding of the area. A full integration of structural interpretation, seismic and sequence stratigraphic principles, biostratigraphy and core studies is required to achieve a realistic interpretation and predict Upper Jurassic facies distributions within this complex area. Utilizing some 30 wells, regional seismic data and biostratigraphy, candidate sequence boundaries and regionally correlatable flooding surfaces (e.g. Eudoxus), have been identified. Horizon flattening on these surfaces has allowed the recognition of thickening-away reflection geometries adjacent to salt features and divergent geometries into graben boundary faults. This facilitates the identification of the dominant local or regional controls on accommodation space creation. Detailed seismic facies analysis was then used to reveal the relative expansion or suppression of depositional systems tracts as a response to either regional or local structural controls. It was subsequently possible to place these systems within a biostratigraphically constrained regional framework. Mapping the base Zechstein, base Jurassic and base Cretaceous horizons has provided a map view of the active faults and slopes controlling sediment transport at any given time. This provided the third dimension essential in depicting the spatial distribution of depositional systems, and is a crucial component of any sequence stratigraphic interpretation. A regional picture of the progressive evolution of this complex area has been thus been derived, and the effect of both regional and local controls on sequence stratigraphic expressions has been determined.

  7. Sea level annual cycle in sea level from tide gauges, altimetry and ocean models in the Polar Seas

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Andersen, O. B.

    2012-04-01

    Lack of adequate spatial and temporal sea level observations in the Polar Seas is one of the most challenging problems in the study of sea level variation and ocean circulation in the regions. The tide gauge data captures local sea level variability with long time span of data. Most of the stations are situated at the Norwegian and Russian border and hereby only observing the easternmost part of the Polar Seas.On the other hand, obtaining satellite data in high latitude regions is generally very problematic. In the Polar Seas, sea level has a significant annual cycle over the coastal regions. In this work, Simple Ocean Data Assimilation (SODA, 1950-2008) and DRAKKAR (ORCA025-G70, 1958-2004) ocean reanalysis are used in conjunction with tide gauge data and altimetric data to investigate the sea level annual cycle in the Polar Seas. The preliminary results show that the amplitude and phase of sea level annual cycle from different data sources are quite difference with each other for the period 1950-1979 and 1980-2008 over the selected regions. To compare with the results from gridded altimetric sea level anomaly maps (ERS-1, ERS-2 and Envisat), more investigation is performed from 1993 to 2009. Moreover, the annual sea level variation from CryoSat-2 data is used for the cross validation.

  8. Colorful Underwater Sea Creatures

    ERIC Educational Resources Information Center

    McCutcheon, Heather

    2011-01-01

    In this article, the author describes a project wherein students created colorful underwater sea creatures. This project began with a discussion about underwater sea creatures and how they live. The first step was making the multi-colored tissue paper that would become sea creatures and seaweed. Once students had the shapes of their sea creatures

  9. Colorful Underwater Sea Creatures

    ERIC Educational Resources Information Center

    McCutcheon, Heather

    2011-01-01

    In this article, the author describes a project wherein students created colorful underwater sea creatures. This project began with a discussion about underwater sea creatures and how they live. The first step was making the multi-colored tissue paper that would become sea creatures and seaweed. Once students had the shapes of their sea creatures…

  10. Beaufort Sea: information update

    SciTech Connect

    Becker, P.R.

    1988-04-01

    The report is based on a multi-disciplinary meeting held March 6-7, 1985, as part of preparations for the Beaufort Sea Sale 97. The chapters are based on presentations given: The causeway effect: Modification of nearshore thermal regime resulting from causeways; Summertime sea ice intrusions in the Chukchi Sea; The deepwater limit of ice gouging on the Beaufort Sea shelf; Distribution, abundance, migration, harvest, and stock identity of Belukha Whales in the Beaufort Sea; Ringed seals in the Beaufort Sea; Beaufort Sea socioeconomics; The Baffin Island Oil Spill, (BIOS) Project.

  11. Dispersal of the radionuclide caesium-137 ((137)Cs) from point sources in the Barents and Norwegian Seas and its potential contamination of the Arctic marine food chain: coupling numerical ocean models with geographical fish distribution data.

    PubMed

    Heldal, Hilde Elise; Vikebø, Frode; Johansen, Geir Odd

    2013-09-01

    Dispersal of (137)Cs from the nuclear submarine wrecks Komsomolets and K-159, which are resting on the seabed in the Norwegian and Barents Seas, respectively, is simulated using realistic rates and hypothetical scenarios. Furthermore, spatiotemporal (137)Cs concentrations in Northeast Arctic cod and capelin are estimated based on survey data. The results indicate that neither continuous leakages nor pulse discharges will cause concentrations of (137)Cs in cod muscle or whole body capelin exceeding the intervention level of 600 Bq/kg fw. Continuous leakages from Komsomolets and K-159 and pulse discharges from Komsomolets induced negligible activity concentrations in cod and capelin. A pulse discharge of 100% of the (137)Cs-inventory of K-159 will, however, result in concentrations in muscle of cod of above 100 times the present levels in the eastern Barents Sea. Within three years after the release, (137)Cs levels above 20 Bq/kg fw in cod are no longer occurring in the Barents Sea. PMID:23771062

  12. Recent glacial events in the Norwegian North Sea - implications towards a better understanding of charging/leakage of oil fields and its impact oil exploration

    NASA Astrophysics Data System (ADS)

    Stoddart, Daniel

    2014-05-01

    Recent drilling and appraisal on the Southern Utsira High, Norwegian North Sea, has proved several large oil/gas discoveries, including the giant Johan Sverdrup, Edvard Grieg, Draupne, Ragnarrock and Apollo oil fields, making this a prolific petroleum area. The Southern Utsira High contains a variety of hydrocarbon density fluids found at several stratigraphic levels illustrating the compartmentalized nature of accumulations and charge history. The Southern Utsira High has been in a position to receive an oil/gas charge for a considerable period of time, with the basin towards the west most likely generating petroleum from early Eocene (50M Mabp) to its maximum present day burial depth. However, reservoir temperatures on the Southern Utsira High are just above the threshold for biodegradation (80°C). The Southern Utsira High oils are non-biodegraded suggesting that the majority of the oil charged relatively late - ca.3 million years ago to present day. The effects of the glaciation on the filling history of the Southern Utsira High are currently being assessed. It is clear that several erosional surfaces in the Pliocene can be identified, as well as glacial channels and moraine deposits, indicating that significant deposition and erosion occurred in the last five million years. Importantly, the effects of glacial rebound mean that the Southern Utsira High more than likely underwent tilting and possible leakage, not just once, but several times in the last 1 million years. The effects of tilting/leakage of geological areas on oil migration have been recognized by several authors. However, the detailed integration of geological mapping and geochemical evidence has not previously been published. The implications of a detailed assessment of tilting of a ''high' through time are; 1) opening up areas where oil migration is thought to be high risk or impossible; 2) identify possible paleo-oil columns aiding the de-risking of discovery appraisal strategies. The evidence of tilting/leakage of oil accumulations through time can be recognized in several oil fields on the Utsira High. The giant Johan Sverdrup discovery oil columns contain paleo-OWC, residual oil zones/paleo-oil columns, and oil shows considerably deeper than the current OWC or residual oil columns. Lundin has performed detailed mapping of the seabed and water column in the Alvheim/Utsira High areas in order to identify areas of gas leakage and its geological manifestations on the seabed and ultimately resulting in the collection of high quality samples. Results shows that gas leakage is prominent over the Alvheim and Utsira High areas and the implications of this to oil exploration will be discussed. In summary, Lundin's approach to oil migration is to better understand the fluid/gas movement throughout the whole basin through time. The talk will focus on the role of glaciations on the timing of charge from the South Viking Graben, fill-spill directions on the Southern Utsira High, the effects of late tilting/leakage on the charge/re-distribution of oil, and seabed / water column characterization and sampling. All placed in the context of oil exploration.

  13. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  14. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  15. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  16. Deep sea waste disposal

    SciTech Connect

    Kester, D.R.; Burt, W.V.; Capuzzo, J.M.; Park, P.K.; Ketchum, B.W.; Duedall, I.W.

    1985-01-01

    The book presents papers on the marine disposal of wastes. Topics considered include incineration at sea, the modelling and biological effects of industrial wastes, microbial studies of ocean dumping, deep-sea mining wastes, the chemical analysis of ferromanganese nodules, and economic aspects of deep-sea disposal.

  17. All That Unplowed Sea

    ERIC Educational Resources Information Center

    MOSAIC, 1975

    1975-01-01

    Hunting and gathering at sea may fast be approaching their productive limits. Aquaculture - farming at sea - linked to conservation represents the sea's promise. If the system works, it might prove to be the key to supplying large amounts of food and fresh water at no cost in nonrenewable energy resources. (BT)

  18. Tracking Sea Otters

    USGS Multimedia Gallery

    Sea otter researchers Michelle Staedler, Monterey Bay Aquarium, and Tim Tinker, USGS, work together to locate sea otters in their study project. USGS scientists and their partners study sea otters in efforts to help the threatened species continue to recover from near extinction....

  19. Cenozoic stratigraphic evolution, North Sea and Labrador Sea

    SciTech Connect

    Gradstein, F.M.; Grant, A.C.; Mudford, B.S. ); Berggren, W.A. ); Kaminski, M.A. ); D'Lorio, M.A. ); Cloetingh, S. ); Griffiths, C.M. )

    1990-05-01

    The authors are studying Cenozoic correlation patterns, burial trends, and subsidence history of the Central North Sea, Labrador, and Orphan basins. The authors objectives are (1) to detail intraregional mid-high latitude biozonations using noise filtering and probabilistic zonation techniques; (2) to detail paleobathymetric trends from basin margins to centers; (3) to apply this knowledge to model basin evolution, in the perspective of the evolving North Atlantic Ocean; (4) to evaluate causes for the occurrence of major hiatuses and rapid changes of subsidence; and (5) to relate rapid changes in sedimentation in the last few millions of years to model observed undercompaction trends. Cenozoic microfossil assemblages in these basins are similar, related to similarities in sedimentary and paleoeceanographic conditions. In more basinal wells, flysch-type agglutinated foraminiferal assemblages occur, also known from Carpathians, Trinidad, and Moroccan foredeeps. Over 90% of agglutinated taxa are common between these basins, although local stratigraphic ranges vary sufficiently to rely on the concept of average ranges, rather than total ones for correlations. Cenozoic stratigraphic resolution in the North Sea and Labrador basins generally is in 3-5-Ma units. and paleobathymetric zonations define a minimum of five niches, from inner shelf to middle slope regimes. Significant hiatuses occurred in the late Eocene through the Miocene, particularly in northern Labrador and northern North Sea. Subsidence in the Labrador/Grand Banks passive margin half grabens was strongly influenced by Labrador Sea opening between anomalies 34 (Campanian) and 13 (early Oligocene), when subsidence exceeded sedimentation and bathyal conditions prevailed along the margin. Thermally induced subsidence in the central North Sea grabens was considerable in the late Paleocene, when the Norwegian Sea started to open.

  20. Regional sea level variability in the Bohai Sea, Yellow Sea, and East China Sea

    NASA Astrophysics Data System (ADS)

    Cheng, Yongcun; Plag, Hans-Peter; Hamlington, Benjamin D.; Xu, Qing; He, Yijun

    2015-12-01

    The regional sea level variability in the Bohai Sea (BS), Yellow Sea (YS) and East China Sea (ECS) is investigated based on tide gauge, satellite altimeter data and an independent oceanic general circulation model for the Earth Simulator (OFES) model outputs. It is found that atmospheric forcing significantly affects local sea level variability in the BS and YS and local sea level variability at the Southern ECS is highly correlated with along-shore currents. Particularly, the annual sea level fluctuations potentially change inundation risk and the frequency and magnitude of flooding in regions with high annual sea level. Hence, the cyclostationary empirical orthogonal function (CSEOF) analysis is carried out to investigate the variations of annual sea level cycle amplitude. Similar spatial distribution characteristics of annual sea level amplitude fluctuations are presented from satellite altimeter data and model outputs. The variability of annual sea level amplitude estimated from the satellite altimeter data agrees well with that from the tide gauge data, and positively (negatively) correlates with Southern Oscillation Index (Pacific Decadal Oscillation). The OFES model, however, underestimates the fluctuation of the annual cycle. After removing the annual signal, the low-passed (i.e., 13-month running mean) tide gauge data shows high correlations with SOI and PDO on time scales over 8 years in the BS and ECS.

  1. Dust Storm, Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Aral Sea has shrunk to less than half its size since 1985. The Aral Sea receives little water (sometimes no water) from the two major rivers that empty into it-the Syr Darya and Amu Darya. Instead, the river water is diverted to support irrigation for the region's extensive cotton fields. Recently, water scarcity has increased due to a prolonged drought in Central Asia. As the Aral Sea recedes, its former sea bed is exposed. The Aral's sea bed is composed of fine sediments-including fertilizers and other agricultural chemicals-that are easily picked up by the region's strong winds, creating thick dust storms. The International Space Station crew observed and recorded a large dust storm blowing eastward from the Aral Sea in late June 2001. This image illustrates the strong coupling between human activities (water diversions and irrigation), and rapidly changing land, sea and atmospheric processes-the winds blow across the

  2. North Sea difficult but prime area for applications

    SciTech Connect

    Skattum, K.S. )

    1990-04-02

    The Norwegian North Sea sector has been considered a very expensive area for subsea developments compared to the Gulf of Mexico and Brazil, where, the cost of a completed subsea well is several times less. An analysis of these large differences shows how the costs for North Sea projects can be reduced.

  3. Sea level extremes in the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Torres, R. Ricardo; Tsimplis, Michael N.

    2014-08-01

    Sea level extremes in the Caribbean Sea are analyzed on the basis of hourly records from 13 tide gauges. The largest sea level extreme observed is 83 cm at Port Spain. The largest nontidal residual in the records is 76 cm, forced by a category 5 hurricane. Storm surges in the Caribbean are primarily caused by tropical storms and stationary cold fronts intruding the basin. However, the seasonal signal and mesoscale eddies also contribute to the creation of extremes. The five stations that have more than 20 years of data show significant trends in the extremes suggesting that flooding events are expected to become more frequent in the future. The observed trends in extremes are caused by mean sea level rise. There is no evidence of secular changes in the storm activity. Sea level return periods have also been estimated. In the south Colombian Basin, where large hurricane-induced surges are rare, stable estimates can be obtained with 30 years of data or more. For the north of the basin, where large hurricane-induced surges are more frequent, at least 40 years of data are required. This suggests that the present data set is not sufficiently long for robust estimates of return periods. ENSO variability correlates with the nontidal extremes, indicating a reduction of the storm activity during positive ENSO events. The period with the highest extremes is around October, when the various sea level contributors' maxima coincide.

  4. The Nordic seas, main oceanographic features

    NASA Astrophysics Data System (ADS)

    Blindheim, Johan; Østerhus, Svein

    This article presents a review of the main oceanographic features of the Nordic Seas (the Greenland, Iceland, and Norwegian Seas). It includes a short description of previous research, the bathymetry of the area, its general circulation, and the exchanges with the North Atlantic and Arctic Oceans. Water mass structure and temporal variations are discussed separately for the various basins. The most prominent variations are a cooling and freshening in the upper layers since the 1960s, particularly in the southwestern Norwegian Sea, and a rise in temperature and salinity in the deeper layers, particularly in the Greenland Sea. Some relations of these variations to ocean—atmosphere interactions are described, and the deep-water warming is ascribed to an increased influence of deep water from the Arctic Ocean and a reduced formation of deep water in the Greenland Sea. Renewal of the deep water in the Greenland Sea occurred in the late 1960s, and atmospheric observations suggest that this may have been the only renewal event in the 20th century.

  5. North Sea HPHT wells require changes in drilling procedures

    SciTech Connect

    Baller, H.

    1991-03-11

    Such equipment as casing, drillstrings, mud, logging, and rigs that were adequate to drill most of the North Sea wells to date will require modifications to drill the high-pressure, high-temperature (HPHT) formations in the Central Graben of the North Sea. HPHT exploration wells are slowly becoming part of the drilling scenario in the North Sea Central Graben. Predominantly drilled in the U.K., an increasing number are now planned for the Norwegian sector during 1991.

  6. East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  7. [The characteristics of the population of the deep waters of the Norwegian Sea in the region of the loss of the Komsomolets nuclear-powered submarine].

    PubMed

    Vinogradov, M E; Shushkina, E A; Vereshchaka, A L; Nezlin, N P

    1995-01-01

    Specific features of vertical distribution and migration of planktonic organisms were studied for estimation of direct pathway of distribution of radionuclides in case they are released in the environment from the sunk nuclear submarine "Komsomolets" (73 degrees 42'N, 13 degrees 15'E, depth 1700 m). The materials were collected by 150-liter bathometers and planktonic nets in July 1994. In addition, planktonic animals were directly counted from deep-sea submarines "Mir". Distribution of the total biomass of plankton was considered and distribution in the water column from the surface to the depth 1700 m was quantitatively estimated for the following species: Calanus finmarchicus, C. hyperboreus, Metridia longa, Euchaeta spp., Sagitta elegans, Themisto abyssorum, and Hymenodora glacialis. The Norway sea hollow is filled by the local Arctic water and this facilitates penetration of many species during seasonal and other migrations down to the demersal layers, i.e., to depths, which are not specific for these organisms in basins with usual water stratification. Mass accumulations of Th. abyssorum have been found in the demersal layer, which is a main component of feeding of commercial plankton-eating fish as well as migrations of this crustacean across the water. PMID:8520439

  8. Pelagic sea snakes dehydrate at sea.

    PubMed

    Lillywhite, Harvey B; Sheehy, Coleman M; Brischoux, François; Grech, Alana

    2014-05-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  9. Pelagic sea snakes dehydrate at sea

    PubMed Central

    Lillywhite, Harvey B.; Sheehy, Coleman M.; Brischoux, Franois; Grech, Alana

    2014-01-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  10. Hawksbill Sea Turtle (Eretmochelys imbricata)

    USGS Multimedia Gallery

    Hawksbill Sea Turtles (Eretmochelys imbricata), such as the one hiding here under a boulder, and Green Sea Turtles (Chelonia mydas) are occasionally seen in Hurricane Hole. Hawksbills feed mostly on sponges while Greens eat mostly sea grasses....

  11. Sea Anemone: Investigations.

    ERIC Educational Resources Information Center

    Hunt, John D.

    1982-01-01

    Several investigations can be undertaken with live sea anemones. A sea anemone's feeding response, fighting power, color, and symbiotic relationships to other invertebrates (such as a marine hermit crab) can be investigated in the high school classroom. Background information and laboratory procedures are provided. (Author/JN)

  12. Tracking Sea Otters

    USGS Multimedia Gallery

    USGS wildlife biologist Alisha Kage holds out a VHF receiver, hoping to hear the tell-tale beep that helps her locate sea otters that are part of study to monitor and learn more about the species. USGS scientists study sea otters in efforts to help the threatened species continue to recover from nea...

  13. Spotting Sea Otters

    USGS Multimedia Gallery

    USGS wildlife biologist Alisha Kage looks through a telescope to help her locate and identify tagged sea otters, then records the otter's location for a study aimed at learning more about the species. USGS scientists study sea otters in efforts to help the threatened species continue to recover from...

  14. Red sea drillings.

    PubMed

    Ross, D A; Whitmarsh, R B; Ali, S A; Boudreaux, J E; Coleman, R; Fleisher, R L; Girdler, R; Manheim, F; Matter, A; Nigrini, C; Stoffers, P; Supko, P R

    1973-01-26

    Recent drilling in the Red Sea has shown that much of the basin is underlain by evaporites of a similar age to that of evaporites found in the Mediterranean Sea. These evaporites and their structural positions indicate that other brine areas are present-and, indeed, several others have been discovered. PMID:17843766

  15. White Sea - Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    At bottom center of this true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from April 13, 2001, the White Sea in western Russia is becoming free of ice in its southern extent. Meanwhile, the blue-green waters along the coast of the peninsula jutting out into the Barents Sea to the northeast could be due to a phytoplankton bloom.

  16. Getting Your Sea Legs

    PubMed Central

    Stoffregen, Thomas A.; Chen, Fu-Chen; Varlet, Manuel; Alcantara, Cristina; Bardy, Benot G.

    2013-01-01

    Sea travel mandates changes in the control of the body. The process by which we adapt bodily control to life at sea is known as getting one's sea legs. We conducted the first experimental study of bodily control as maritime novices adapted to motion of a ship at sea. We evaluated postural activity (stance width, stance angle, and the kinematics of body sway) before and during a sea voyage. In addition, we evaluated the role of the visible horizon in the control of body sway. Finally, we related data on postural activity to two subjective experiences that are associated with sea travel; seasickness, and mal de debarquement. Our results revealed rapid changes in postural activity among novices at sea. Before the beginning of the voyage, the temporal dynamics of body sway differed among participants as a function of their (subsequent) severity of seasickness. Body sway measured at sea differed among participants as a function of their (subsequent) experience of mal de debarquement. We discuss implications of these results for general theories of the perception and control of bodily orientation, for the etiology of motion sickness, and for general phenomena of perceptual-motor adaptation and learning. PMID:23840560

  17. Experimental investigation of deep sea riser interaction

    SciTech Connect

    Huse, E.

    1996-12-31

    In future deep sea field developments the drag force and corresponding static deflections of the risers due to current can become quite large. The prevention of mechanical contact (collision) between the risers will need more careful evaluation than in moderate water depths. The paper describes a series of model experiments in a Norwegian fjord to determine criteria for on-set of collisions between the risers of a deep sea TLP. The current was modeled using the natural tidal current in the fjord. Results from the tests are summarized and used for verification of numerical calculations of collision criteria.

  18. Black Sea in Bloom

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of biological activity currently ongoing. The brownish pixels in the Azov are probably sediments carried in from high waters upstream. This scene was acquired by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on May 4, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is 'one of the marine areas of the world most damaged by human activities.' The coastal zone around these Eastern European inland water bodies is densely populated-supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem. Working with a spirit of placing more emphasis on joint ownership of the Black Sea's resources, and less emphasis on blame, it is hoped that the cooperating countries can strike an effective balance between both enjoying and preserving the Black Sea. Image courtesy the SeaWiFS Project, NASA GSFC, and ORBIMAGE

  19. Global sea level rise

    SciTech Connect

    Douglas, B.C. )

    1991-04-15

    Published values for the long-term, global mean sea level rise determined from tide gauge records exhibit considerable scatter, from about 1 mm to 3 mm/yr. This disparity is not attributable to instrument error; long-term trends computed at adjacent sites often agree to within a few tenths of a millimeter per year. Instead, the differing estimates of global sea level rise appear to be in large part due to authors' using data from gauges located at convergent tectonic plate boundaries, where changes of land elevation give fictitious sea level trends. In addition, virtually all gauges undergo subsidence or uplift due to postglacial rebound (PGR) from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling PGR by the ICE-3G model of Tushingham and Peltier (1991) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. The value for mean sea level rise obtained from a global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 is 1.8 mm/yr {plus minus} 0.1. This result provides confidence that carefully selected long tide gauge records measure the same underlying trend of sea level and that many old tide gauge records are of very high quality.

  20. Dead sea water intoxication.

    PubMed

    Levy-Khademi, Floris; Brooks, Rebecca; Maayan, Channa; Tenenbaum, Ariel; Wexler, Isaiah D

    2012-08-01

    Near drowning in the Dead Sea is associated with both respiratory manifestations and severe electrolyte abnormalities. It is often difficult to distinguish between the contributions of sea water aspiration or ingestion to clinical manifestations. We present a unique case of accidental ingestion of a large amount of Dead Sea water through a gastrostomy tube in which a patient with familial dysautonomia presented with severe electrolyte disturbances. Forced diuresis with large amounts of intravenous fluids resulted in clinical and biochemical improvement. Full recovery was achieved after 2 days of treatment. PMID:22863826

  1. Sea level variation

    NASA Technical Reports Server (NTRS)

    Douglas, Bruce C.

    1992-01-01

    Published values for the long-term, global mean sea level rise determined from tide gauge records range from about one to three mm per year. The scatter of the estimates appears to arise largely from the use of data from gauges located at convergent tectonic plate boundaries where changes of land elevation give fictitious sea level trends, and the effects of large interdecadal and longer sea level variations on short (less than 50+ years) or sappy records. In addition, virtually all gauges undergo subsidence or uplift due to isostatic rebound from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling rebound by the ICE-3G model of Tushingham and Peltier (1990) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. A global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 yields the global sea level rise value 1.8 mm/year +/- 0.1. Greenhouse warming scenarios commonly forecast an additional acceleration of global sea level in the next 5 or 6+ decades in the range 0.1-0.2 mm/yr2. Because of the large power at low frequencies in the sea level spectrum, very long tide gauge records (75 years minimum) have been examined for past apparent sea level acceleration. For the 80-year period 1905-1985, 23 essentially complete tide gauge records in 10 geographic groups are available for analysis. These yielded the apparent global acceleration -0.011 (+/- 0.012) mm/yr2. A larger, less uniform set of 37 records in the same 10 groups with 92 years average length covering the 141 years from 1850-1991 gave 0.001 (+/- 0.008) mm/yr2. Thus there is no evidence for an apparent acceleration in the past 100+ years that is significant either statistically, or in comparison to values associated with global warming. Unfortunately, the large interdecadal fluctuations of sea level severely affect estimates of global sea level acceleration for time spans of less than about 50 years. This means that tide gauges alone cannot serve as a reliable leading indicator of climate change in less than many decades. This time required can be significantly reduced if the interdecadal fluctuations of sea level can be understood in terms of their forcing mechanisms, and then removed from the tide gauge records.

  2. Sea Perch Project

    NASA Technical Reports Server (NTRS)

    2010-01-01

    David Lalejini, an employee of the Naval Research Laboratory at NASA's John C. Stennis Space Center, helps a pair of teachers deploy a remotely-operated underwater Sea Perch robot during workshop activities Dec. 11. The Stennis Education Office teamed with Naval Research Laboratory counterparts to conduct a two-day workshop Dec. 10-11 for Louisiana and Mississippi teachers. During the no-cost workshop, teachers learned to build and operate Sea Perch robots. The teachers now can take the Sea Perch Program back to students.

  3. Sea Ice Ecosystems

    NASA Astrophysics Data System (ADS)

    Arrigo, Kevin R.

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters.

  4. Sea level change

    SciTech Connect

    Meier, M.F.

    1996-12-31

    The IPCC (Intergovernmental Panel on Climate Change) 1995 Scientific Assessment, Chapter 7. Sea Level Change, presents a modest revision of the similar chapter in the 1990 Assessment. Principal conclusions on observed sea-level change and the principal terms in the sea-level equation (ocean thermal expansion, glaciers, ice sheets, and land hydrology), including our knowledge of the present-day (defined as the 20th Century) components of sea-level rise, and projections of these for the future, are presented here. Some of the interesting glaciological problems which are involved in these studies are discussed in more detail. The emphasis here is on trends over decades to a century, not on shorter variations nor on those of the geologic past. Unfortunately, some of the IPCC projections had not been agreed at the time of writing of this paper, and these projections will not be given here. 15 refs., 2 figs.

  5. North Sea rift system

    NASA Astrophysics Data System (ADS)

    Ziegler, P. A.

    1992-07-01

    The Mesozoic North Sea rift forms an integral part of the Arctic-North Atlantic rift system. Rifting activity in the North Sea commenced during the earliest Triassic. During the mid-Jurassic the central North Sea underwent a temporary doming stage. Crustal extension peaked during the Late Jurassic-earliest Cretaceous, abated subsequently and terminated altogether during the Paleocene. The saucer-shaped Cenozoic post-rift basin straddles the axis of the Viking and Central grabens. This speaks for the applicability of a depth dependent pure shear model rather than a simple shear model. Geophysical data indicate an important discrepancy between upper and lower crustal attenuation across the North Sea rift, suggesting that during rifting processes the Mono-discontinuity was seriously destabilized. This requires a basic modification of currently favoured crustal stretching models.

  6. Dead Sea Scrolls

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A consortium of researchers from Jet Propulsion Laboratory and three other organizations used charged coupled devices (CCDs) and other imaging enhancement technology to decipher previously unreadable portions of the Dead Sea Scrolls. The technique has potentially important implications for archeology.

  7. Alaska: Beaufort Sea

    Atmospheric Science Data Center

    2014-05-15

    ... satellite remote sensing instruments; the synthetic aperture radar (SAR) on board the RADARSAT satellite and the Multi-angle Imaging ... by how the surface and subsurface roughness influence radar backscatter. In the SAR image, white lines delineate different sea ice ...

  8. Record Sea Ice Minimum

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Arctic sea ice reached a record low in September 2007, below the previous record set in 2005 and substantially below the long-term average. This image shows the Arctic as observed by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) aboard NASA's Aqua satellite on September 16, 2007. In this image, blue indicates open water, white indicates high sea ice concentration, and turquoise indicates loosely packed sea ice. The black circle at the North Pole results from an absence of data as the satellite does not make observations that far north. Three contour lines appear on this image. The red line is the 2007 minimum, as of September 15, about the same time the record low was reached, and it almost exactly fits the sea ice observed by AMSR-E. The green line indicates the 2005 minimum, the previous record low. The yellow line indicates the median minimum from 1979 to 2000.

  9. Sensing the sea bed

    NASA Astrophysics Data System (ADS)

    2009-07-01

    William Wilcock and a team of scientists and engineers drilled holes in the sea floor, and inadvertently provided a breeding ground for octopuses, in their attempt to understand deep-ocean hydrothermal venting.

  10. Teacher at Sea.

    ERIC Educational Resources Information Center

    Beighley, Karl

    1998-01-01

    Outlines the experiences of a teacher in the National Oceanic and Atmospheric Administration's (NOAA) Teacher At Sea Program in which teachers are placed on NOAA vessels to work with professional scientists doing critical, real world research. (DDR)

  11. Black Sea Becomes Turquoise

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of color variance. The brownish pixels in the Azov are probably due to sediments carried in from high waters and snowmelt from upstream. This scene was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA's Terra satellite, on May 14, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is ?one of the marine areas of the world most damaged by human activities.? The coastal zone around these Eastern European inland water bodies is densely populated'supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem. Working with a spirit of placing more emphasis on joint ownership of the Black Sea's resources, and less emphasis on blame, it is hoped that the cooperating countries can strike an effective balance between both enjoying and preserving the Black Sea.

  12. South China Sea.

    PubMed

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the South China Sea. What data are available, however, and if Hong Kong is used, as it is herein, as an indicator of what the perturbations of other regional cities upon the South China Sea are like, then it is impacted grossly and an ecological disaster has probably already, but unknowingly, happened. PMID:11827109

  13. Contemporary sea level rise.

    PubMed

    Cazenave, Anny; Llovel, William

    2010-01-01

    Measuring sea level change and understanding its causes has considerably improved in the recent years, essentially because new in situ and remote sensing observations have become available. Here we report on most recent results on contemporary sea level rise. We first present sea level observations from tide gauges over the twentieth century and from satellite altimetry since the early 1990s. We next discuss the most recent progress made in quantifying the processes causing sea level change on timescales ranging from years to decades, i.e., thermal expansion of the oceans, land ice mass loss, and land water-storage change. We show that for the 1993-2007 time span, the sum of climate-related contributions (2.85 +/- 0.35 mm year(-1)) is only slightly less than altimetry-based sea level rise (3.3 +/- 0.4 mm year(-1)): approximately 30% of the observed rate of rise is due to ocean thermal expansion and approximately 55% results from land ice melt. Recent acceleration in glacier melting and ice mass loss from the ice sheets increases the latter contribution up to 80% for the past five years. We also review the main causes of regional variability in sea level trends: The dominant contribution results from nonuniform changes in ocean thermal expansion. PMID:21141661

  14. Annual sea ice. An air-sea gas exchange moderator

    SciTech Connect

    Gosink, T.A.; Kelley, J.J.

    1982-01-01

    Arctic annual sea ice, particularly when it is relatively warm (> -15/sup 0/C) permits significant gas exchange between the sea and air throughout the entire year. Sea ice, particularly annual sea ice, differs from freshwater ice with respect to its permeability to gases. The presence of brine allows for significant air-sea-ice exchange of CO/sub 2/ throughout the winter, which may significantly affect the global carbon dioxide balance. Other trace gases are also noted to be enriched in sea ice, but less is known about their importance to air-sea-interactions at this time. Both physical and biological factors cause and modify evolution of gases from the surface of sea ice. Quantitative and qualitative descriptions of the nature and physical behavior of sea ice with respect to brine and gases are discussed.

  15. The White Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Editor's Note: The caption below, published on May 10, 2001, is incorrect. According to Masha Vorontsova, director of the International Fund for Animal Welfare in Moscow, the situation with the seal pups in the White Sea is normal. There is no disaster and there never was. For more details, refer to the article entitled 'No Danger' on the New Scientist home page. The Earth Observatory regrets the earlier errant report. Original Caption According to the Russian Polar Research Institute for Fisheries and Oceanography, between 250,000 and 300,000 Greenland seal pups face death by starvation over the next two months due to a cruel trick by mother nature. The seals, most of them less than two months old, are trapped on ice sheets that remain locked in the White Sea, located near Archangel in Northern Russia. Typically, during the spring thaw the ice sheets break up and flow with the currents northward into the Barents Sea, the seals' spring feeding grounds. The seal pups hitch a ride on the ice floes, living on their own individual stores of fat until they arrive in the Barents Sea. Their mothers departed for the Barents Sea weeks ago. In a normal year, the seal pups' trip from the White Sea out to the Barents takes about six weeks and the seals have adapted to rely upon this mechanism of mother nature. During their yearly migration, the mother seals usually stay with their pups and feed them until their pelts turn from white to grey--a sign that the pups are mature enough to swim and feed themselves. Unfortunately, this year unusually strong northerly winds created a bottleneck of ice near the mouth of the white sea, thus blocking the flow of ice and trapping the pups. These true-color images of the White Sea were acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. This image, taken May 2, 2000 that there is usually much less ice in the White Sea this time of year as most of it is typically en route to the Barents Sea.

  16. North Sea development activity surges

    SciTech Connect

    Not Available

    1992-08-10

    This paper reports that operators in the North Sea have reported a burst of upstream activity. Off the U.K.: Amoco (U.K.) Exploration Co. installed three jackets in its North Everest and Lomond fields. It also completed laying the Central Area Transmission System (CATS) pipeline, which will carry the fields' gas to shore. BP Exploration Operating Co. Ltd. installed the jacket for it Unity riser platform 5 {1/2} km from its Forties Charlie platform. Conoco (U.K.) Ltd. tested a successful appraisal well in Britannia field in Block 15/30, about 130 miles northeast of Aberdeen. In the Norwegian North Sea, Saga Petroleum AS placed Snorre oil and gas field on production 6 weeks ahead of schedule and 1.5 billion kroner under budget at a cost of 16.6 billion kroner; and downstream off the U.K., Phillips Petroleum Co. (U.K.) Ltd. awarded Allseas Marine Contractors SA, Essen, Belgium, a pipelay and trenching contract for its Ann field development project in Block 49/6a.

  17. The Dead Sea

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 18.5 by 48.1 kilometers (11.5 by 29.8 miles) Location: 31.4 degrees North latitude, 35.4 degrees East longitude Orientation: North at top Image Data: ASTER bands 3, 2, and 1 Original Data Resolution: 15 meters (49.2 feet) Dates Acquired: May 3, 2005

  18. Influence of the White Sea on tides in adjacent marginal seas of the North European Basin

    NASA Astrophysics Data System (ADS)

    Kagan, B. A.; Sofina, E. V.; Rashidi, E. H. A.

    2013-01-01

    An investigation into the interaction of surface M 2 tides in the system of marginal seas of the North European Basin is carried out using the three-dimensional finite-element hydrostatic model QUODDY-4. Three numerical experiments are performed for this purpose. In the first (control), the model equations are solved in the system of the Norwegian, Greenland, Barents, and White seas; thereby the interaction of the tides in these seas is explicitly taken into account. In the second experiment, the White Sea is excluded from consideration and the no-flux condition is posed at the entrance to the sea. The third experiment uses an approach in which the observed tidal elevations that determine the existence of a finite horizontal transport of barotropic energy to the White Sea are specified at the open boundary of the White Sea. It is shown that changes in tidal dynamics represented by changes in the amplitudes and phases of tidal elevations and in the barotropic tidal velocity ellipse parameters are within the model noise in experiments 2 and 3 when compared with the control experiment. On the contrary, changes in energy characteristics (the horizontal wave transport, density, and dissipation rate of barotropic tidal energy) are equal to or greater (in order of magnitude) than the energy characteristics themselves.

  19. On large outflows of Arctic sea ice into the Barents Sea

    NASA Technical Reports Server (NTRS)

    Kwok, Ron; Maslowski, Wieslaw; Laxon, Seymour W.

    2005-01-01

    Winter outflows of Arctic sea ice into the Barents Sea are estimated using a 10-year record of satellite ice motion and thickness. The mean winter volume export through the Svalbard/Franz Josef Land passage is 40 km3, and ranges from -280 km3 to 340 km3. A large outflow in 2003 is preconditioned by an unusually high concentration of thick perennial ice over the Nansen Basin at the end of the 2002 summer. With a deep atmospheric low situated over the eastern Barents Sea in winter, the result is an increased export of Arctic ice. The Oct-Mar ice area flux, at 110 x 10 to the third power km3, is not only unusual in magnitude but also remarkable in that >70% of the area is multiyear ice; the ice volume flux at340 km3 is almost one-fifth of the ice flux through the Fram Strait. Another large outflow of Arctic sea ice through this passage, comparable to that in 2003, is found in 1996. This southward flux of sea ice represents one of two major sources of freshwater in the Barents Sea; the other is the eastward flux of water via the Norwegian Coastal Current. The possible consequences of variable freshwater input on the Barents Sea hydrography and its impact on transformation of Atlantic Water en route to the Arctic Ocean are examined with a 25-year coupled ice-ocean model.

  20. Upper ocean heat content in the Nordic seas

    NASA Astrophysics Data System (ADS)

    di Iorio, Daniela; Sloan, Caitlin

    2009-04-01

    Seven years of temperature profiles are obtained from the Argo float project and are used to study the vertically integrated heat content for the Nordic seas which is broken up into the Norwegian Basin, Greenland Sea, Lofoten region, and Iceland Plateau. The World Ocean Atlas 2005 (WOA05) is used as the climatological baseline for temperature and hence heat content. Temporally and spatially averaged temperature profiles within the Norwegian and Iceland basins show good agreement between the Argo and WOA05 data sets. For the Greenland and Lofoten basins, the WOA05 data show cooler surface temperatures (by 1-2C) but still lie within 1 standard deviation of each other over the 7-year period. The Argo float data show circulation within each of the basins that is counterclockwise, and some of the floats eventually disperse toward the outer edges of the basins. Vertically integrated heat content from 0 to 1200 m shows similar characteristics as the WOA05 results including the timing and strength of the seasonal variability. The anomalous heat content for the Greenland and Norwegian sea basins is calculated in depth bins of 400 m. The Greenland Sea shows a warming trend over the 7 years of study, which corresponds to a temperature increase of (4.1 0.3) 10-2 C/yr. The Norwegian Sea basin shows interannual variability in heat content for the surface layer (0-400 m) that may be related to the North Atlantic Oscillation (NAO). During an NAO+ phase, the Norwegian Basin shows a warm phase, and during an NAO- phase, the Norwegian Basin is in a cold phase; the correlation is small (r = 0.32) but different from zero correlation only at the 90% level, implying that the variability in the AHC may be due to (1) local atmospheric forcing and hence changes in heat loss, (2) atmospheric pressure differences that are not resolved by the NAO index, and (3) exchange of heat with the basin boundaries.

  1. A lithosphere-scale structural model of the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, P.; Faleide, J. I.; Scheck-Wenderoth, M.; Sippel, J.

    2015-02-01

    We introduce a regional 3-D structural model of the Barents Sea and Kara Sea region which is the first to combine information on the sediments and the crystalline crust as well as the configuration of the lithospheric mantle. Therefore, we have integrated all available geological and geophysical data, including interpreted seismic refraction and reflection data, seismological data, geological maps and previously published 3-D models into one consistent model. This model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian) the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distributions of the corresponding main megasequences delineate five major subdomains (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian-Greenland Sea and the Eurasia Basin). Relating the subsidence histories of these subdomains to the structure of the deeper crust and lithosphere sheds new light on possible causative basin forming mechanisms that we discuss. The depth configuration of the newly calculated LAB and the seismic velocity configuration of the upper mantle correlate with the younger history of this region. The western Barents Sea is underlain by a thinned lithosphere (80 km) resulting from multiple Phanerozoic rifting phases and/or the opening of the NE Atlantic from Paleocene/Eocene times on. Notably, the northwestern Barents Sea and Svalbard are underlain by thinnest continental lithosphere (60 km) and a low-velocity/hot upper mantle that correlates spatially with a region where late Cenozoic uplift was strongest. As opposed to this, the eastern Barents Sea is underlain by a thicker lithosphere (~ 110-150 km) and a high-velocity/density anomaly in the lithospheric mantle. This anomaly, in turn, correlates with an area where only little late Cenozoic uplift/erosion was observed.

  2. Caribbean Sea Level Network

    NASA Astrophysics Data System (ADS)

    von Hillebrandt-Andrade, C.; Crespo Jones, H.

    2012-12-01

    Over the past 500 years almost 100 tsunamis have been observed in the Caribbean and Western Atlantic, with at least 3510 people having lost their lives to this hazard since 1842. Furthermore, with the dramatic increase in population and infrastructure along the Caribbean coasts, today, millions of coastal residents, workers and visitors are vulnerable to tsunamis. The UNESCO IOC Intergovernmental Coordination Group for Tsunamis and other Coastal Hazards for the Caribbean and Adjacent Regions (CARIBE EWS) was established in 2005 to coordinate and advance the regional tsunami warning system. The CARIBE EWS focuses on four areas/working groups: (1) Monitoring and Warning, (2) Hazard and Risk Assessment, (3) Communication and (4) Education, Preparedness and Readiness. The sea level monitoring component is under Working Group 1. Although in the current system, it's the seismic data and information that generate the initial tsunami bulletins, it is the data from deep ocean buoys (DARTS) and the coastal sea level gauges that are critical for the actual detection and forecasting of tsunamis impact. Despite multiple efforts and investments in the installation of sea level stations in the region, in 2004 there were only a handful of sea level stations operational in the region (Puerto Rico, US Virgin Islands, Bermuda, Bahamas). Over the past 5 years there has been a steady increase in the number of stations operating in the Caribbean region. As of mid 2012 there were 7 DARTS and 37 coastal gauges with additional ones being installed or funded. In order to reach the goal of 100 operational coastal sea level stations in the Caribbean, the CARIBE EWS recognizes also the importance of maintaining the current stations. For this, a trained workforce in the region for the installation, operation and data analysis and quality control is considered to be critical. Since 2008, three training courses have been offered to the sea level station operators and data analysts. Other requirements and factors have been considered for the sustainability of the stations. The sea level stations have to potentially sustain very aggressive conditions of not only tsunamis, but on a more regular basis, hurricanes. Given the requirement that the data be available in near real time, for tsunami and other coastal hazard application, robust communication systems are also essential. For the local operator, the ability to be able to visualize the data is critical and tools like the IOC Sea level Monitoring Facility and the Tide Tool program are very useful. It has also been emphasized the need for these stations to serve multiple purposes. For climate and other research applications the data need to be archived, QC'd and analyzed. Increasing the user base for the sea level data has also been seen as an important goal to gain the local buy in; local weather and meteorological offices are considered as key stakeholders but for whom applications still need to be developed. The CARIBE EWS continues to look forward to working with other IOC partners including the Global Sea Level Observing System (GLOSS) and Sub-Commission for the Caribbean and Adjacent Regions (IOCARIBE)/GOOS, as well as with local, national and global sea level station operators and agencies for the development of a sustainable sea level network.

  3. Understanding Sea Level Changes

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    2004-01-01

    Today more than 100 million people worldwide live on coastlines within one meter of mean sea level; any short-term or long-term sea level change relative to vertical ground motion is of great societal and economic concern. As palm-environment and historical data have clearly indicated the existence and prevalence of such changes in the past, new scientific information regarding to the nature and causes and a prediction capability are of utmost importance for the future. The 10-20 cm global sea-level rise recorded over the last century has been broadly attributed to two effects: (1) the steric effect (thermal expansion and salinity-density compensation of sea water) following global climate; (2) mass-budget changes due to a number of competing geophysical and hydrological processes in the Earth-atmosphere-hydrosphere-cryosphere system, including water exchange from polar ice sheets and mountain glaciers to the ocean, atmospheric water vapor and land hydrological variations, and anthropogenic effects such as water impoundment in artificial reservoirs and extraction of groundwater, all superimposed on the vertical motions of solid Earth due to tectonics, rebound of the mantle from past and present deglaciation, and other local ground motions. As remote-sensing tools, a number of space geodetic measurements of sea surface topography (e.g., TOPEX/Poseidon, Jason), ice mass (e.g., ICESat), time-variable gravity (e.g. GRACE), and ground motions (SLR, VLBI, GPS, InSAR, Laser altimetry, etc.) become directly relevant. Understanding sea level changes "anywhere, anytime" in a well-defined terrestrial reference frame in terms of climate change and interactions among ice masses, oceans, and the solid Earth, and being able to predict them, emerge as one of the scientific challenges in the Solid Earth Science Working Group (SESWG, 2003) conclusions.

  4. Mechanisms of long-term mean sea level variability in the North Sea

    NASA Astrophysics Data System (ADS)

    Dangendorf, Snke; Calafat, Francisco; ie Nilsen, Jan Even; Richter, Kristin; Jensen, Jrgen

    2015-04-01

    We examine mean sea level (MSL) variations in the North Sea on timescales ranging from months to decades under the consideration of different forcing factors since the late 19th century. We use multiple linear regression models, which are validated for the second half of the 20th century against the output of a state-of-the-art tide+surge model (HAMSOM), to determine the barotropic response of the ocean to fluctuations in atmospheric forcing. We demonstrate that local atmospheric forcing mainly triggers MSL variability on timescales up to a few years, with the inverted barometric effect dominating the variability along the UK and Norwegian coastlines and wind (piling up the water along the coast) controlling the MSL variability in the south from Belgium up to Denmark. However, in addition to the large inter-annual sea level variability there is also a considerable fraction of decadal scale variability. We show that on decadal timescales MSL variability in the North Sea mainly reflects steric changes, which are mostly remotely forced. A spatial correlation analysis of altimetry observations and baroclinic ocean model outputs suggests evidence for a coherent signal extending from the Norwegian shelf down to the Canary Islands. This supports the theory of longshore wind forcing along the eastern boundary of the North Atlantic causing coastally trapped waves to propagate along the continental slope. With a combination of oceanographic and meteorological measurements we demonstrate that ~80% of the decadal sea level variability in the North Sea can be explained as response of the ocean to longshore wind forcing, including boundary wave propagation in the Northeast Atlantic. These findings have important implications for (i) detecting significant accelerations in North Sea MSL, (ii) the conceptual set up of regional ocean models in terms of resolution and boundary conditions, and (iii) the development of adequate and realistic regional climate change projections.

  5. Spectacled Eiders Wintering in Northern Bering Sea

    USGS Multimedia Gallery

    Large flock of Spectacled Eiders aggregated in a sea ice lead and on sea ice in the northern Bering Sea, south of St. Lawrence Island, Alaska.  Aerial photograph from a helicopter deployed from the USCG Cutter Polar Sea....

  6. Seafloor Control on Sea Ice

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Clemente-Colon, P.; Rigor, I. G.; Hall, D. K.; Neumann, G.

    2011-01-01

    The seafloor has a profound role in Arctic sea ice formation and seasonal evolution. Ocean bathymetry controls the distribution and mixing of warm and cold waters, which may originate from different sources, thereby dictating the pattern of sea ice on the ocean surface. Sea ice dynamics, forced by surface winds, are also guided by seafloor features in preferential directions. Here, satellite mapping of sea ice together with buoy measurements are used to reveal the bathymetric control on sea ice growth and dynamics. Bathymetric effects on sea ice formation are clearly observed in the conformation between sea ice patterns and bathymetric characteristics in the peripheral seas. Beyond local features, bathymetric control appears over extensive ice-prone regions across the Arctic Ocean. The large-scale conformation between bathymetry and patterns of different synoptic sea ice classes, including seasonal and perennial sea ice, is identified. An implication of the bathymetric influence is that the maximum extent of the total sea ice cover is relatively stable, as observed by scatterometer data in the decade of the 2000s, while the minimum ice extent has decreased drastically. Because of the geologic control, the sea ice cover can expand only as far as it reaches the seashore, the continental shelf break, or other pronounced bathymetric features in the peripheral seas. Since the seafloor does not change significantly for decades or centuries, sea ice patterns can be recurrent around certain bathymetric features, which, once identified, may help improve short-term forecast and seasonal outlook of the sea ice cover. Moreover, the seafloor can indirectly influence cloud cover by its control on sea ice distribution, which differentially modulates the latent heat flux through ice covered and open water areas.

  7. Egyptian Sea Cave

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    This brief article describes an archaeological expedition to the Red Sea coast area of Egypt in 2004. Kathryn Bard, an associate professor of archaeology at Boston University, along with her team, discovered the well-preserved cedar timbers of an ancient Egyptian seafaring vessel near the entrance to a large man-made cave. Limestone tablets with

  8. The Provident Sea

    NASA Astrophysics Data System (ADS)

    Cushing, David H.

    1988-09-01

    The Provident Sea describes the history of fish stock management (including whales and seals). The book traces, on the basis of the original scientific material, the history of the management of "the provident sea" up to recent times when problems of over-exploitation have had dramatic effects upon stocks. The need for management arose mainly from the increasing industrialization of capture. Hence the preindustrial fisheries are covered, in particular the old cod fishery on the Grand Bank and the herring fishery in the North Sea, as an essential background to current problems. The origins of fisheries and whaling science are described, as is the development up to 1965 of the science and institution in fisheries, whaling, and sealing. In the sixties and seventies, certain major fishing nations took a heavy harvest of fish stocks using sophisticated and efficient gathering methods. This in turn led to conflict and one consequence was the "Law of the Sea" conference set up to try and resolve these issues.

  9. S.E.A.

    ERIC Educational Resources Information Center

    Hawkins, Richard H.

    1976-01-01

    Sea Semester combines a six-week apprenticeship on a sailing ship with an intensive shore preparation component. Through Boston University, students learn marine and nautical sciences before putting some of this information to practice. Students, having completed the shore and sailing components, can enroll in more advanced shore component

  10. S.E.A.

    ERIC Educational Resources Information Center

    Hawkins, Richard H.

    1976-01-01

    Sea Semester combines a six-week apprenticeship on a sailing ship with an intensive shore preparation component. Through Boston University, students learn marine and nautical sciences before putting some of this information to practice. Students, having completed the shore and sailing components, can enroll in more advanced shore component…

  11. Solomon's Sea and [Pi

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2009-01-01

    This paper is a whimsical survey of the various explanations which might account for the biblical passage in I Kings 7:23 that describes a round object--a bronze basin called Solomon's Sea--as having diameter ten cubits and circumference thirty cubits. Can the biblical pi be any number other than 3? We offer seven different perspectives on this

  12. Sea Surface Temperature

    EPA Science Inventory

    This indicator presents global mean sea surface temperature (SST) anomalies from 1880 to 2010. SST is a critical physical attribute of marine and coastal ecosystems that directly affects biological and physical process rates, water column stability, and the presence and health...

  13. Solar Sea Power

    ERIC Educational Resources Information Center

    Zener, Clarence

    1976-01-01

    In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

  14. Harvesting the Sea.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1989-01-01

    Information on commercial fishing is provided, and a board game is described which requires students to watch for ocean signs of good fishing, choose equipment to catch specific types of fish, and consider effects of weather on working at sea. A reproducible copy of the game, with instructions, is included. (IAH)

  15. Farming the Sea

    ERIC Educational Resources Information Center

    Morgan, William

    1971-01-01

    Florida has initiated a training program in an entirely new dimension--Sea Farming. Presented is a description of the vocational agriculture program designed to teach propagation, cultivation, harvesting, marketing, and conservation practices related to production of oysters, shrimp, scallops, crabs, and fin fishes. (Editor/GB)

  16. Learning from the Sea

    ERIC Educational Resources Information Center

    Acker, Susan

    1973-01-01

    Introduces a series of articles relating to learning from the sea. Marine science programs provide a rich experience for students making them aware of interrelationships and concerned about preserving marine habitats and solving environmental problems. Stresses the importance of involvement in successfully studying the ocean world. (JR)

  17. Ships to the Sea.

    ERIC Educational Resources Information Center

    Department of the Navy, Washington, DC.

    This lesson contains materials for the U.S. Navy Museum's "Ships to the Sea" program. The program is appropriate for students in grades 2-4 and was designed in accordance with local and national social studies standards. The materials introduce students to the world of ship technology and naval terminology. The lesson is presented in five

  18. Egyptian Sea Cave

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    This brief article describes an archaeological expedition to the Red Sea coast area of Egypt in 2004. Kathryn Bard, an associate professor of archaeology at Boston University, along with her team, discovered the well-preserved cedar timbers of an ancient Egyptian seafaring vessel near the entrance to a large man-made cave. Limestone tablets with…

  19. Sea Grant's Education Mission.

    ERIC Educational Resources Information Center

    Sherman, Douglas

    1998-01-01

    Considers the status of the education agenda of the Sea Grant Program as it turns 30. Projects described include Operation Pathfinder, which aims to educate minority teachers and/or teachers of minority students. Also described are a program in which seafood processors and resellers are trained in safety and health areas, and programs to train

  20. Virtual sea border

    NASA Astrophysics Data System (ADS)

    Ferriere, D.; Rucinski, A.; Jankowski, T.

    2007-04-01

    Establishing a Virtual Sea Border by performing a real-time, satellite-accessible Internet-based bio-metric supported threat assessment of arriving foreign-flagged cargo ships, their management and ownership, their arrival terminal operator and owner, and rewarding proven legitimate operators with an economic incentive for their transparency will simultaneously improve port security and maritime transportation efficiencies.

  1. Classroom of the Sea.

    ERIC Educational Resources Information Center

    Hupper, Mary Laporta; Monte, Denise; Scheifele, Peter

    2000-01-01

    Introduces the Sea Program in which participant students were deaf and collaborated with a bioacoustician. Studies the underwater noise levels of the Gulf of Maine and the possible impacts on marine life. Explains implementing this project in the science curriculum. (YDS)

  2. Barents Sea crustal architecture and basin development

    NASA Astrophysics Data System (ADS)

    Faleide, J. I.

    2012-04-01

    The Barents Sea continental shelf is characterized by a complex tectonic history and thus comprises a wide range of crustal and basin architectures that formed in response to different geological processes. Overlapping Paleozoic orogenies (Timanian, Caledonian, Uralian) preceded multiple rift episodes mainly affecting the western Barents Sea and eventual breakup with Greenland to the west and Lomonosov Ridge to the north. Recent work related to the PETROBAR and BarMod projects has provided new details on basin architecture, tectonic and thermal histories, stratigraphy, paleogeography, paleo-water depths and the role of the basement grain in the structuring of the Barents Sea basins. The eastern Barents Sea comprises a wide and deep sag basin that formed by rapid subsidence in Late Permian-Early Triassic times, most likely in response to basin-forming mechanisms other than rifting. The deep East Barents Sea Basin was filled by thick uppermost Permian and Triassic sediments prograding westwards from uplifted source areas mainly in the SE (Urals). In the western Barents Sea we find more typical rift basins formed in response to at least three major post-Caledonian rift phases: Carboniferous, Late Jurassic-Early Cretaceous, and Late Cretaceous-early Paleogene. The rifting activity migrated westwards through successive tectonic phases. Carboniferous rifting affected the entire western Barents Sea and gave rise to NE-SW to N-S trending horst and graben structures following a Caledonian basement grain. These structures were covered by a regional carbonate platform before renewed faulting affected the SW Barents Sea in Late Permian time. The major prograding system reached the western Barents Sea in earliest Triassic time gradually filling in a regional basin of considerable waterdepths. Late Jurassic-Early Cretaceous oblique extension and formation of the deep SW Barents Sea basins was linked to the North Atlantic-Arctic plate tectonic evolution. Regional uplift associated with the Early Cretaceous High Arctic Large Igneous Province gave rise to a depositional system characterized by north to south progradation covering most of the Barents Sea. Volcanic extrusives are preserved in the northern Barents Sea, mainly on Franz Josef Land and eastern Svalbard, while intrusives are found widespread, particularly in the deep East Barents Sea Basin. A Late Cretaceous-Early Paleogene mega-shear system along the western Barents Sea-Svalbard margin (De Geer Zone) linked rifting, breakup and initial opening of the Norwegian-Greenland Sea and the Arctic Eurasia Basin. Narrow pull-apart basins formed within this dominantly shear system, in particular at a releasing bend in the margin SW of Bjørnøya. A restraining bend SW of Svalbard gave rise to the transpressional Spitsbergen Fold-and-Thrust Belt. Compressional structures of different styles are found widespread in the Barents Sea region. The nature and timing of these are difficult to constrain in many areas due to later uplift and erosion, but we expect that there are different causes and timing involved. At the western margin we see evidence of compressional deformation as young as Miocene in age. The entire Barents Shelf was uplifted and eroded during Neogene time and thick fans of Plio-Pleistocene glacial sediments were formed in front of bathymetric troughs characteristic of both the western and northern Barents Sea. Most of the uplift is closely linked to the glacial erosion, but tectonic uplift occurred prior to the glaciations.

  3. The Weddell Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Several large, irregularly shaped icebergs are floating in the Weddell Sea, east of the Antarctic Peninsula, in this true-color MODIS image from February 17, 2002. The location of several of the bergs has changed little over the last three months. Compared to an image acquired on November 13, 2001, the berg at the upper right of the image has spun around, but is still hanging around in the same general location. Similar slow-movers can be seen just to the east of the Larsen Ice Shelf, which hugs the eastern coast of the Peninsula. The northernmost of those two bergs is designated A38b; the southernmost one is A38a. These bergs were once part of an iceberg greater than 2,700 square miles that broke off the Ronne Ice Shelf (to the south) back in 1998. While the waters of the Weddell Sea in the area ought to be deep enough to float those bergs, it is possible that they have run aground on a topographic high, or ridge, in the sea floor. However, little is known about the underwater topography of that region, and it is also possible that the bergs are simply so massive that they resist being moved by surface wind or ocean currents. While four years might seem like a long time for an iceberg to hang around, these are certainly no record holders. A berg that broke off the Ross Ice Shelf (on the other side of Antarctica) drifted north and went aground south of Australia. That berg calved in 1987, and hasn't really moved in ten years. While the big bergs have not moved much in the span of time between these images, there is a big difference in the amount of sea ice present in the two images. In general, the rounder chunks of ice are more likely to be seasonal sea ice that forms from the freezing of sea water, while the larger, jagged-edged pieces of ice are more likely to be bergs that broke off an ice shelf at the margin of the continent. It's the height of summer in Antarctica in the February image, and much of the sea ice has melted or drifted away, leaving a relatively large expanse of clear ocean. Credit:

  4. Northern Sand Sea

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    This VIS image was taken at 82 degrees North latitude during Northern spring. The image is completely dominated by dunes. In sand seas, it is very common for a single type of dune to occur, and for a single predominate wind to control the alignment of the dunes.

    Image information: VIS instrument. Latitude 82.2, Longitude 152.5 East (207.5 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. Sea-Level Projections from the SeaRISE Initiative

    NASA Technical Reports Server (NTRS)

    Nowicki, Sophie; Bindschadler, Robert

    2011-01-01

    SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

  6. North Sea Sediment Dynamics

    NASA Astrophysics Data System (ADS)

    Paetsch, Johannes; Kuehn, Wilfried; Serna, Alexandra; Lahajnar, Niko; Emeis, Kay

    2014-05-01

    The North Sea is a semi-enclosed shelf sea attached to the North-east Atlantic and in its south-eastern part receives significant matter from river discharge and atmospheric deposition: Anthropogenic nutrients, dissolved carbon and organic compounds have elevated pristine background concentrations in the coastal strip of the North Sea since about 250 years as a consequence of intensified agriculture and industrialisation since then, In such a marine environment the legacy of old inputs and the influence of processes in the sediment on the biogeochemistry of the overlying water column increases with decreasing water depth. On the other hand the flux of particulate organic matter into the surface sediment (~15 cm depth) also increases with decreasing water depth or distance from the coast. Both effects are also described by results of ECOHAM-M simulations, the coupled pelagic-benthic ecosystem model that includes a prognostic multi-layer sediment module adopted from the global biogeochemical model HAMOCC as part of the MPI-earth-system model (MPI-ESM).The transfer from deep sea to coastal applications required different adaptations, such as changes in porosity values, in dissolution and organic matter remineralisation rates, and stoichiometries. In the model, two pelagic detritus pools, one slowly sinking with semi-labile organic matter, and one fast sinking with labile organic matter are collected in one sediment pool. After a spin-up of several hundred years the 3d-coupled model for the southern and central North Sea attains equilibrium, where the local inputs and outputs of the pelagic and benthic module are balanced. From this equilibrium state we initialised a realistic decadal run (2000-2009). Analysing the seasonal and interannual model results we found that the variability of sediment efflux in the model is low compared to the more dynamic pelagic system components, but simulated (and observed) sediment pore water profiles clearly show concentration gradients from the coast into the central North Sea. Data on organic matter concentration and quality in surface sediments along a comparable transect suggest that not only the loading with POM decreases with distance to land, but also the reactivity of organic matter, indicated by amino acid composition as a measure of the degree of protein degradation. This ageing or degradation effect can also be seen in a near-shore surface sediment core where the C/N ratio increases with depth, while the relative concentration of labile material in sedimentary organic matter decreases. We discuss how the quality of organic particulate matter could be integrated into the sediment model equations.

  7. Marginal seasTerminological crisis

    NASA Astrophysics Data System (ADS)

    Mazarovich, A. O.

    2011-07-01

    The terms marginal sea, peripheral sea, and backarc sea are widely used in the contemporary Russian geological literature as synonyms but do not have, in my opinion, unequivocal treatment. The application of the term marginal sea is briefly discussed. The seas of the Pacific transitional zone are reviewed. It is proposed to define a marginal sea as a marine basin a few thousand kilometers in extent and connected with the open ocean. Domains underlain by crust of the continental and oceanic types must coexist therein. The domains with oceanic crust are expressed in the topography as deepwater basins (one or several), where fragments of continental crust may also occur. A marginal sea must be bounded by at least one island arc.

  8. The North Sea - A shelf sea in the Anthropocene

    NASA Astrophysics Data System (ADS)

    Emeis, Kay-Christian; van Beusekom, Justus; Callies, Ulrich; Ebinghaus, Ralf; Kannen, Andreas; Kraus, Gerd; Kröncke, Ingrid; Lenhart, Hermann; Lorkowski, Ina; Matthias, Volker; Möllmann, Christian; Pätsch, Johannes; Scharfe, Mirco; Thomas, Helmuth; Weisse, Ralf; Zorita, Eduardo

    2015-01-01

    Global and regional change clearly affects the structure and functioning of ecosystems in shelf seas. However, complex interactions within the shelf seas hinder the identification and unambiguous attribution of observed changes to drivers. These include variability in the climate system, in ocean dynamics, in biogeochemistry, and in shelf sea resource exploitation in the widest sense by societies. Observational time series are commonly too short, and resolution, integration time, and complexity of models are often insufficient to unravel natural variability from anthropogenic perturbation. The North Sea is a shelf sea of the North Atlantic and is impacted by virtually all global and regional developments. Natural variability (from interannual to multidecadal time scales) as response to forcing in the North Atlantic is overlain by global trends (sea level, temperature, acidification) and alternating phases of direct human impacts and attempts to remedy those. Human intervention started some 1000 years ago (diking and associated loss of wetlands), expanded to near-coastal parts in the industrial revolution of the mid-19th century (river management, waste disposal in rivers), and greatly accelerated in the mid-1950s (eutrophication, pollution, fisheries). The North Sea is now a heavily regulated shelf sea, yet societal goals (good environmental status versus increased uses), demands for benefits and policies diverge increasingly. Likely, the southern North Sea will be re-zoned as riparian countries dedicate increasing sea space for offshore wind energy generation - with uncertain consequences for the system's environmental status. We review available observational and model data (predominantly from the southeastern North Sea region) to identify and describe effects of natural variability, of secular changes, and of human impacts on the North Sea ecosystem, and outline developments in the next decades in response to environmental legislation, and in response to increased use of shelf sea space.

  9. The Aral Sea Disaster

    NASA Astrophysics Data System (ADS)

    Micklin, Philip

    2007-05-01

    The Aral Sea is a huge terminal lake located among the deserts of Central Asia. Over the past 10 millennia, it has repeatedly filled and dried, owing both to natural and human forces. The most recent desiccation started in the early 1960s and owes overwhelmingly to the expansion of irrigation that has drained its two tributary rivers. Lake level has fallen 23 m, area shrunk 74%, volume decreased 90%, and salinity grew from 10 to more than 100g/l, causing negative ecological changes, including decimation of native fish species, initiation of dust/salt storms, degradation of deltaic biotic communities, and climate change around the former shoreline. The population residing around the lake has also been negatively impacted. There is little hope in the foreseeable future to fully restore the Aral Sea, but measures to preserve/rehabilitate parts of the water body and the deltas are feasible.

  10. Summer at-sea distribution of seabirds and marine mammals in polar ecosystems: a comparison between the European Arctic seas and the Weddell Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Joiris, Claude R.

    2000-12-01

    The summer at-sea distribution of seabirds and marine mammals was quantitatively established both in Antarctica (Weddell Sea) and in the European Arctic: Greenland, Norwegian and Barents seas. Data can directly be compared, since the same transect counts were applied by the same team from the same icebreaking ship in both regions. The main conclusion is that densities of seabirds and marine mammals are similar in open water and at the ice edge from both polar regions, while the presence of Adlie penguins, minke whales and crabeater seals in densities more than one order of magnitude higher in Antarctic pack-ice must reflect a major ecological difference between both polar systems. The ecological implications of these observations are discussed, especially concerning important primary and secondary (krill) productions under the Weddell Sea pack-ice.

  11. Drillship for rough seas

    SciTech Connect

    Penn, J.T.

    1982-11-01

    PENN ENGINEERING of Orange, Texas, extending a concept previously applied to a drilling tender, has designed a pair of economical new drillships that will enlarge the weather window for drilling in many severe environments. Two factors make this possible: an external motion suppression system that reduces roll by as much as 90% and heave by as much as 40%, and A central mooring system that makes it possible to turn the vessel 90/sup 0/ in either direction to head into the seas.

  12. Dead Sea rhodopsins revisited.

    PubMed

    Bodaker, Idan; Suzuki, Marcelino T; Oren, Aharon; Bj, Oded

    2012-12-01

    The Dead Sea is a unique hypersaline ecosystem with near toxic magnesium levels (?2?M), dominance of divalent cations and a slightly acidic pH. Previously, we reported a haloarchaeon related to Halobacterium salinarum to dominate in a microbial bloom that developed in 1992 in the upper water layers of the lake following massive freshwater runoff. Whether this clade also dominated an earlier bloom in 1980-1982 cannot be ascertained as no samples for cultivation-independent analysis were preserved. The presence of the light-driven proton pump bacteriorhodopsin was reported in the 1980-1982 bloom of prokaryotes that had developed in the Dead Sea. To test the hypothesis that bacteriorhodopsin proton pumping may play a major role in determining what type of haloarchaea may dominate in specific bloom conditions, we compared rhodopsin genes recovered from Dead Sea biomass collected in different periods with genes coding for retinal proteins in isolated haloarchaea. Novel bacteriorhodopsin and sensory rhodopsin genes were found in samples collected in 2007 and 2010. The fact that no rhodopsin genes were recovered from samples collected during the 1992 bloom, which was dominated by a single species, suggests that different clades were present in the 1980-1982 and 1992 blooms, and that bacteriorhodopsin proton pumping did not necessarily play a determinative role in the dominance of specific halophiles in the blooms. PMID:23760932

  13. Curonian Spit, Baltic Sea

    NASA Technical Reports Server (NTRS)

    2006-01-01

    On July 25, 2006, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), flying on NASA's Terra satellite, captured this image of the Curonian (or Courland)spit, the Curonian Lagoon (also known as the Courland Lagoon) it encloses, and part of the Baltic Sea. Just 3,800 meters (about 12,460 feet) at its widest point, the spit encloses a lagoon of some 1,620 square kilometers (625 square miles). In this image, dark blue indicates deep water, and lighter blue indicates shallow and/or sediment-laden water. Different shades of blue distinguish the deeper Baltic Sea and the shallower Curonian Lagoon. Vegetation appears in varying shades of green, paved surfaces and bare ground appear in shades of beige and gray, and sandy areas appear off-white. Obvious sandy areas appear along the length of the spit. On the Baltic Sea side, a thin off-white band of beach runs the length of the spit; on the Curonian Lagoon side, intermittent beaches carve their way into the narrow strip of land.

  14. Kara Sea radioactivity assessment.

    PubMed

    Osvath, I; Povinec, P P; Baxter, M S

    1999-09-30

    Investigations following five international expeditions to the Kara Sea have shown that no radiologically significant contamination has occurred outside of the dumping sites in Novaya Zemlya bays. Increased levels of radionuclides in sediment have only been observed in Abrosimov and Stepovoy Bays very close to dumped containers. Evaluations of radionuclide inventories in water and sediment of the open Kara Sea and Novaya Zemlya bays as well as soil from the shore of Abrosimov bay have shown that radionuclide contamination of the open Kara Sea is mainly due to global fallout, with smaller contributions from the Sellafield reprocessing plant, the Chernobyl accident run-off from the Ob and Yenisey rivers and local fallout. Computer modelling results have shown that maximum annual doses of approximately 1 mSv are expected for a hypothetical critical group subsisting on fish caught in the Novaya Zemlya bays whereas populations living on the mainland can be expected to receive doses at least three orders of magnitude lower. PMID:10568274

  15. Water Mass Properties and Distribution between South China Sea, Sulu Sea and Celebes Sea

    NASA Astrophysics Data System (ADS)

    Fadzil Akhir, Mohd; Arsad, Shukri

    2013-04-01

    A definition of water mass properties, characteristics and its origin along the coast of northern Borneo are presented based on 55 CTD casts cruises in July 2009 combined with five Argo profiling floats at surrounding seas. The T-S relation in the study area, which includes South China Sea, Sulu Sea and Celebes Sea, show existences of eight water masses. In reference of earlier studies, we define water masses in the surface mixed layer with strong mixed of Open Sea Water (OSW), Continental Shelf Water (CSW) and Tropical Surface Water (TSW). Below the layer of this active mixing is a zone of rapid transition called the Seasonal Thermocline Water (STW). Meanwhile, the Maximum Salinity Water (MSW), Permanent Thermocline Water (PTW), North Pacific Intermediate Water (NPIW) and Deep Water (DW) were found at the depth range from below the seasonal thermocline to about 1000 m. In addition, study of BRAN (BLUElink ReANalysis) global ocean model was conducted to demonstrate how current circulation influence the exchange of water mass between the 3 seas. Sulu Sea sits in the middle and has very limited connection between the other two seas. Connection with Celebes Sea occurs at the inlet of 200m depth. Water exchange happens in two ways; surface inflow and subsurface outflow. While in South China Sea, inlet is limited to 50m depth and surface flow is mostly dominant. The current circulation of the adjacent sea demonstrate some of the water mass were origiated as far as north South China Sea and Pacific Ocean. Water mass differences between the seas were further classified to distinguish dissimilarities and define the origin the difference. Given the unique geographical background and current circulation of the area, the characteristics of the interaction between water mass distribution and current circulation has provide important overview to the area which previously not well understood.

  16. Modeling study of tidal effects on the Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Lee, Ho Jin; Kwon, Mi Ok; Nam, Jong Ho; Seo, Young-Kyo

    2015-04-01

    We investigate the tidal effects on the sea-ice distribution of the Arctic Ocean using an ice-coupled Ocean General Circulation Model (OGCM). The model covers the Arctic Ocean with the adjacent seas including Norwegian Sea, Greenland Sea and Hudson Bay. The horizontal grid size ranges from 23 to 30 km. A total of 50 s-coordinate levels are adopted along the vertical direction with enhanced resolution near the surface. After 10years spinning up model, we conducted a hindcast simulation from January 1, 1980 to the end of 2013 with a 12-hourly atmospheric forcing. Four major tidal forcing (M2, S2, K1, O1) are included along the open boundaries based on TPXO7. Model results show that there are no substantial changes in the sea ice volume of the Arctic Ocean except around Canadian Arctic Archipelago where the sea-ice thickness is significantly decreased in summer. The enhanced currents and mixing by tide seems to increase the sea-ice melting there. The enhanced mixing affects subsurface temperature distributions in the Barents Sea as well.

  17. Sea Salt Source Function over the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Petelski, Tomasz; Makuch, Przemyslaw; Markuszewski, Piotr; Jankowski, Andrzej; Zieli?ski, Tymon

    2013-04-01

    Studies of production and transport of aerosol over the sea are very important for many areas of knowledge. Marine aerosol emitted from the sea surface helps to clean the boundary layer from other aerosol particles. The emitted droplets do not dry out in the highly humid surface layer air and because of their sizes most of them are deposited quickly at the sea surface. Therefore, marine aerosol has many features of rain i.e. the deposition in the marine boundary layer in high wind events is controlled not only by the "dry" processes but also by the "wet" scavenging. While many cruises conducted on board S/Y Oceania, we collected many data which were used to calculate sea salt source function over the Baltic Sea. Our cruises held between 2009 and 2012. Measurements were carried out using gradient method. For this method we used Laser Particle Counter (PMS model CSASP-100_HV) placed on one oft the mast of S/Y Oceania. Measurements were performed on five different levels around sea level: 8, 11, 14, 17 and 20 meters. Based on the averaged vertical concentration, profiles were calculated, using Monin-Obuchow theory, vertical sea spray fluxes in the near water layer. Based on fluxes calculated from vertical concentration profiles was calculated sea salt source function over the Baltic Sea. This function gives emission for different particle size, depending on environmental parameters. Emission of sea spray depends of the size of energy lost by the wind waves in process of collapse. Acknowledgements: The support for this study was provided by the project Satellite Monitoring of the Baltic Sea Environment - SatBa?tyk founded by European Union through European Regional Development Fund contract No. POIG 01.01.02-22-011/09.

  18. Experiencing the Full Research Process at Sea Education Association (SEA)

    NASA Astrophysics Data System (ADS)

    Harris, S. E.; Joyce, P.; Jaroslow, G.; Graziano, L.; Lea, C.; Witting, J.; Bower, A.

    2003-12-01

    While some undergraduate research experiences include only a small piece of the research process, students attending Sea Education Association's SEA Semester complete all aspects of oceanographic research in an intensive 12 week program that earns a full semester's credit. In the first half of the program, students read and discuss background literature on a subject, ask questions, pose hypotheses, and develop a written research proposal, which they defend orally. The second half of the course takes place at sea on one of SEA's state-of-the-art oceanographic research vessels where students carry out their sampling plans, analyze samples and data, write a final paper and present their results before the vessel reaches port, completing the course. At sea, students participate in sample collection and analysis for all student projects in addition to learning the general oceanography along their cruise track. This structure exposes students to the realities of research from start to finish and allows them to take full ownership of their projects. In addition to honing writing, public speaking, and problem-solving skills, students learn that research requires dedication, flexibility, and creativity, particularly when their results are unexpected or negate their hypothesis. SEA's undergraduate research program has been developing since 1971. Over that time, SEA has collected an extensive historical oceanographic database in the western Atlantic and Caribbean, plus Pacific data since 2001. This database is available to both students and outside research scientists. Collaborations with scientists outside SEA enhance the student experience and help facilitate oceanographic research by providing "ship-of-opportunity" sampling in remote locations. SEA Semester provides an excellent model for undergraduate research experiences with over 5000 alumni, about 30% of whom enter graduate school. About half the students in SEA's undergraduate programs are non-science majors. Although their experience at SEA may be their only hands-on exposure to scientific research, they take away an understanding of the process and an ability to think critically about scientific problems.

  19. Regime shifts in North Sea and Baltic Sea: A comparison

    NASA Astrophysics Data System (ADS)

    Dippner, Joachim W.; Mller, Caroline; Hnninen, Jari

    2012-12-01

    The ICES subdivisions in the North Sea (SD IIIa, SD IVa, and SD IVb) and the subdivisions in the Baltic Sea (SD 29, SD 27/28-2, and SD 25/26) are selected to compare the response in long term monitoring data (1970-2000) with respect to climate regime shifts. A modified AMOEBA model is applied to the data sets to identify the status and development of the North Sea and Baltic Sea system during two recent regime shifts. Biological regime shifts can be identified 1989/1990 in SD IIIa in the North Sea and in SD 25/26 in the Baltic Sea. A synchronous appearance of regime shifts could only be identified in the central and southern Baltic Sea for both regime shifts 1975/76 and 1989/90 where the AMOEBA model indicated a high similarity in ecosystem response. A clear difference was identified in the response of the North Sea and the Baltic Sea. Inter-annual and inter-decadal variability as well as regime shifts are driven in the Baltic Sea by direct atmospheric forcing only. In contrast, the changes in the North Sea are influenced by both the direct atmospheric forcing and the indirect forcing from the changes in North Atlantic. The fact that regime shifts as well as their synchronous appearance can be identified with the AMOEBA model might be of major interest for the management of sustainable use of ecosystem goods and services, the development of ecosystem approach to management and the implementation of the Marine Strategy Framework Directive (MSFD) of the European Union (EU).

  20. Sea Otter, River Otter. The Wonder Series.

    ERIC Educational Resources Information Center

    Robinson, Sandra Chisholm

    This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The…

  1. Sea Otter, River Otter. The Wonder Series.

    ERIC Educational Resources Information Center

    Robinson, Sandra Chisholm

    This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The

  2. The USGS Salton Sea Science Office

    USGS Publications Warehouse

    Case, Harvey Lee, III; Barnum, Douglas A.

    2007-01-01

    The U.S. Geological Survey's (USGS) Salton Sea Science Office (SSSO) provides scientific information and evaluations to decisionmakers who are engaged in restoration planning and actions associated with the Salton Sea. The primary focus is the natural resources of the Salton Sea, including the sea?s ability to sustain biological resources and associated social and economic values.

  3. The Sea Around Us

    NASA Astrophysics Data System (ADS)

    Carson, Rachel L.

    1991-12-01

    Published in 1951, The Sea Around Us is one of the most remarkably successful books ever written about the natural world. Rachel Carson's rare ability to combine scientific insight with moving, poetic prose catapulted her book to first place on The New York Times best-seller list, where it enjoyed wide attention for thirty-one consecutive weeks. It remained on the list for more than a year and a half and ultimately sold well over a million copies, has been translated into 28 languages, inspired an Academy Award-winning documentary, and won both the 1952 National Book Award and the John Burroughs Medal. This classic work remains as fresh today as when it first appeared. Carson's writing teems with stunning, memorable images--the newly formed Earth cooling beneath an endlessly overcast sky; the centuries of nonstop rain that created the oceans; giant squids battling sperm whales hundreds of fathoms below the surface; and incredibly powerful tides moving 100 billion tons of water daily in the Bay of Fundy. Quite simply, she captures the mystery and allure of the ocean with a compelling blend of imagination and expertise. Reintroducing a classic work to a whole new generation of readers, this Special Edition features a new chapter written by Jeffrey Levinton, a leading expert in marine ecology, that brings the scientific side of The Sea Around Us completely up to date. Levinton incorporates the most recent thinking on continental drift, coral reefs, the spread of the ocean floor, the deterioration of the oceans, mass extinction of sea life, and many other topics. In addition, acclaimed nature writer Ann Zwinger has contributed a brief foreword. Today, with the oceans endangered by the dumping of medical waste and ecological disasters such as the Exxon oil spill in Alaska, this illuminating volume provides a timely reminder of both the fragility and the importance of the ocean and the life that abounds within it. Anyone who loves the sea, or who is concerned about our natural environment, will want to read this classic work.

  4. Two Sea-Level Challenges

    NASA Astrophysics Data System (ADS)

    Galvin, C.

    2008-12-01

    "No place on the sandy ocean shores of the world has been shown to be eroding because of sea level rise." This statement appeared nearly 19 years ago in bold print at the top of the page in a brief article published in Shore and Beach (Galvin,1990). The term "sea level rise" was defined in 1990 as follows: "In this statement, "sea level rise" has the meaning that the average person on the street usually attaches to that term. That is, sea level is rising; not, as in some places like the Mississippi River delta, land level is sinking." While still a subject of controversy, it is now (2008) increasingly plausible (Tornqvist et al,2008) that damage from Hurricane Katrina was significantly worse on the Mississippi River delta because floodwaters exploited wetlands and levees whose elevations had been lowered by decades of compaction in the underlying soil. (1) "Sea level" commonly appears in the literature as "relative sea level rise", occurring that way in 711 publications between 1980 and 2009 (GeoRef database on 8 Sep 08). "Relative sea level rise" does not appear in the 2005 AGI Glossary. The nearest Glossary term is "relative change in sea level", but that term occurs in only 12 publications between 1980 and 2009. The Glossary defines this term in a sequence stratigraphy sense, which infers that "relative sea level rise" is the sum of bottom subsidence and eustatic sea level rise. In plain English, "relative sea level rise" means "water depth increase". For present day coastal environments, "relative sea level rise" is commonly used where eustatic sea level rise is less than subsidence, that is, where the magnitude of actual sea level rise is smaller than the magnitude of subsidence. In that situation, "relative sea level rise" misleads both the average person and the scientist who is not a coastal geologist. Thus, the first challenge is to abandon "relative sea level rise" in favor of "water depth increase", in order that the words accurately descibe what happens. It would further clarify popular understanding if the term "actual sea level rise" were used in place of "eustatic sea level rise". (2)Geologists have approximated the the practice of paleontologists and biologists in establishing type examples of important geological features. This is a useful practice. A graduate geologist holds in mind clear conceptions of "beach cusps", "drumlin fields", "birdfoot deltas", and "igneous sills" based on seeing field examples accepted by professional geologists as representative of these features. However, although publications frequently report that sea level rise erodes a particular beach, no one identifies a type beach where that cause has been proven to produce the alleged effect. At the type beach, it is necessary to show that sea level is rising, and that the beach erodes primarily from this sea level rise, rather than from interrupted longshore transport. Thus, the second challenge is to identify a type ocean beach proven to erode because of sea level rise.

  5. Holocene sea surface temperature and sea ice extent in the Okhotsk and Bering Seas

    NASA Astrophysics Data System (ADS)

    Harada, Naomi; Katsuki, Kota; Nakagawa, Mitsuhiro; Matsumoto, Akiko; Seki, Osamu; Addison, Jason A.; Finney, Bruce P.; Sato, Miyako

    2014-08-01

    Accurate prediction of future climate requires an understanding of the mechanisms of the Holocene climate; however, the driving forces, mechanisms, and processes of climate change in the Holocene associated with different time scales remain unclear. We investigated the drivers of Holocene sea surface temperature (SST) and sea ice extent in the North Pacific Ocean, and the Okhotsk and Bering Seas, as inferred from sediment core records, by using the alkenone unsaturation index as a biomarker of SST and abundances of sea ice-related diatoms (F. cylindrus and F. oceanica) as an indicator of sea ice extent to explore controlling mechanisms in the high-latitude Pacific. Temporal changes in alkenone content suggest that alkenone production was relatively high during the middle Holocene in the Okhotsk Sea and the western North Pacific, but highest in the late Holocene in the eastern Bering Sea and the eastern North Pacific. The Holocene variations of alkenone-SSTs at sites near Kamchatka in the Northwest Pacific, as well as in the western and eastern regions of the Bering Sea, and in the eastern North Pacific track the changes of Holocene summer insolation at 50N, but at other sites in the western North Pacific, in the southern Okhotsk Sea, and the eastern Bering Sea they do not. In addition to insolation, other atmosphere and ocean climate drivers, such as sea ice distribution and changes in the position and activity of the Aleutian Low, may have systematically influenced the timing and magnitude of warming and cooling during the Holocene within the subarctic North Pacific. Periods of high sea ice extent in both the Okhotsk and Bering Seas may correspond to some periods of frequent or strong winter-spring dust storms in the Mongolian Gobi Desert, particularly one centered at ?4-3 thousand years before present (kyr BP). Variation in storm activity in the Mongolian Gobi Desert region may reflect changes in the strength and positions of the Aleutian Low and Siberian High. We suggest that periods of eastward displacement or increased intensity of the Aleutian Low correspond with times of increased extent of sea ice in the western Okhotsk Sea and eastern Bering Sea.

  6. Sea modeling and rendering

    NASA Astrophysics Data System (ADS)

    Cathala, Thierry; Latger, Jean

    2010-10-01

    More and more defence and civil applications require simulation of marine synthetic environment. Currently, the "Future Anti-Surface-Guided-Weapon" (FASGW) or "anti-navire léger" (ANL) missile needs this kind of modelling. This paper presents a set of technical enhancement of the SE-Workbench that aim at better representing the sea profile and the interaction with targets. The operational scenario variability is a key criterion: the generic geographical area (e.g. Persian Gulf, coast of Somalia,...), the type of situation (e.g. peace keeping, peace enforcement, anti-piracy, drug interdiction,...)., the objectives (political, strategic, or military objectives), the description of the mission(s) (e.g. antipiracy) and operation(s) (e.g. surveillance and reconnaissance, escort, convoying) to achieve the objectives, the type of environment (Weather, Time of day, Geography [coastlines, islands, hills/mountains]). The paper insists on several points such as the dual rendering using either ray tracing [and the GP GPU optimization] or rasterization [and GPU shaders optimization], the modelling of sea-surface based on hypertextures and shaders, the wakes modelling, the buoyancy models for targets, the interaction of coast and littoral, the dielectric infrared modelling of water material.

  7. A Silurian sea spider.

    PubMed

    Siveter, Derek J; Sutton, Mark D; Briggs, Derek E G; Siveter, David J

    2004-10-21

    Pycnogonids (sea spiders) are marine arthropods numbering some 1,160 extant species. They are globally distributed in depths of up to 6,000 metres, and locally abundant; however, their typically delicate form and non-biomineralized cuticle has resulted in an extremely sparse fossil record that is not accepted universally. There are two opposing views of their phylogenetic position: either within Chelicerata as sister group to the euchelicerates, or as a sister taxon to all other euarthropods. The Silurian Herefordshire Konservat-Lagerstatte in England (approximately 425 million years (Myr) bp) yields exceptionally preserved three-dimensional fossils that provide unrivalled insights into the palaeobiology of a variety of invertebrates. The fossils are preserved as calcitic void in-fills in carbonate concretions within a volcaniclastic horizon, and are reconstructed digitally. Here we describe a new pycnogonid from this deposit, which is the oldest adult sea spider by approximately 35 Myr and the most completely known fossil species. The large chelate first appendage is consistent with a chelicerate affinity for the pycnogonids. Cladistic analyses place the new species near the base of the pycnogonid crown group, implying that the latter had arisen by the Silurian period. PMID:15496921

  8. Greenland Sea observations

    SciTech Connect

    Gudmandsen, P.; Mortensen, H.B.; Pedersen, L.T.; Skriver, H.; Minnett, P.

    1992-12-31

    ERS-1 SAR data have been acquired over the Greenland Sea and Fram Strait during two periods, the Ice Phase of three-day repeat cycle from January to March 1992 and a one-month period in the 35-day repeat cycle from 16 July to 15 August 1992. Most data became available by way of the Broadband Data Dissemination System, i.e. with a spatial resolution of about 100 m. With these data various algorithms have been tested to derive sea ice parameters such as ice extent, ice concentration and ice displacement. In the latter period data were collected to support the activities of a research vessel in the area mainly related to the large polynyas that form east and north of Greenland. The formation of polynyas could clearly be outlined but also other phenomena were observed related to the influence of wind streets and gravity waves associated with the atmospheric boundary layer. The data will have to be studied further including full-resolution data to substantiate the conclusions arrived at.

  9. Spectacled Eiders Wintering in Northern Bering Sea

    USGS Multimedia Gallery

    Large flock of Spectacled Eiders aggregated in a sea ice lead in the northern Bering Sea, south of St. Lawrence Island, Alaska.  Aerial photograph from a helicopter deployed from the USCG Cutter Polar Sea....

  10. Spectacled Eiders Wintering in Northern Bering Sea

    USGS Multimedia Gallery

    Large flock of Spectacled Eiders aggregated in a sea ice lead in the northern Bering Sea, south of St. Lawrence Island, Alaska.  Aerial photograph from a helicopter deployed from the USCG Cutter Polar Sea. ...

  11. Spectacled Eiders Wintering in Northern Bering Sea

    USGS Multimedia Gallery

    Large flock of Spectacled Eiders aggregated in a sea ice lead at sunset in the northern Bering Sea, south of St. Lawrence Island, Alaska.  Aerial photograph from a helicopter deployed from the USCG Cutter Polar Sea....

  12. ROC Sampling Deep Sea Urchin

    USGS Multimedia Gallery

    Images of the remotely operated vehicle Jason2 sampling a sea urchin in a deep sea mussel community found near a gas seep on the U.S. outer continental shelf. Images courtesy Deepwater Canyons 2013 - Pathways to the Abyss expedition, NOAA-OER/BOEM/USGS....

  13. Arctic Sea ice model sensitivities.

    SciTech Connect

    Peterson, Kara J.; Bochev, Pavel Blagoveston; Paskaleva, Biliana Stefanova

    2010-12-01

    Arctic sea ice is an important component of the global climate system and, due to feedback effects, the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice state to internal model parameters. A new sea ice model that holds some promise for improving sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of this MPM sea ice code and compare it with the Los Alamos National Laboratory CICE code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness,and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution.

  14. Probability of sea level rise

    SciTech Connect

    Titus, J.G.; Narayanan, V.K.

    1995-10-01

    The report develops probability-based projections that can be added to local tide-gage trends to estimate future sea level at particular locations. It uses the same models employed by previous assessments of sea level rise. The key coefficients in those models are based on subjective probability distributions supplied by a cross-section of climatologists, oceanographers, and glaciologists.

  15. The Barbados Sea Level Record

    NASA Astrophysics Data System (ADS)

    Fairbanks, R. G.; Mortlock, R. A.; Abdul, N. A.; Wright, J. D.; Cao, L.; Mey, J. L.

    2013-12-01

    Additional offshore drill cores, nearly 100 new radiometric dates, and more than 1000 kilometers of Multibeam mapping greatly enhance the Barbados Sea Level record. Extensive Multibeam mapping around the entire island covers approximately 2650 km2 of the sea bottom and now integrates the offshore reef topography and Barbados Sea Level Record with the unparalleled onshore core collection, digital elevation maps, and Pleistocene sea level record spanning the past one million years. The reef crest coral, Acropora palmata, remains the stalwart indicator of sea level for many reasons that are validated by our redundant sea level records and redundant dating via Th/U and Pa/U analyses. Microanalysis and densitometry studies better explain why Acropora palmata is so well preserved in the Pleistocene reef records and therefore why it is the species of choice for sea level reconstructions and radiometric dating. New drill cores into reefs that formed during Marine Isotope Stage 3 lead us to a model of diagenesis that allows us to better prospect for unaltered coral samples in older reefs that may be suitable for Th/U dating. Equally important, our diagenesis model reinforces our rigorous sample quality criteria in a more quantitative manner. The Barbados Sea Level record has a sampling resolution of better than 100 years throughout much of the last deglaciation showing unprecedented detail in redundant drill cores. The Melt Water Pulses (MWP1A and MWP1B) are well resolved and the intervening interval that includes the Younger Dryas reveals sea level changes in new detail that are consistent with the terrestrial records of ice margins (see Abdul et al., this section). More than 100 paired Th/U and radiocarbon ages place the Barbados Sea Level Record unambiguously on the radiocarbon time scale for direct comparisons with the terrestrial records of ice margin changes.

  16. Occurrence of rogue sea states and consequences for marine structures

    NASA Astrophysics Data System (ADS)

    Bitner-Gregersen, Elzbieta M.; Toffoli, Alessandro

    2014-10-01

    The frequency of occurrence of combined wave systems like wind sea and swell may increase in some ocean areas due to the observed change of storm tracks. These combined sea states, when crossing at a particular angle, may lead to more frequent occurrence of rogue events. The present study addresses these rogue-wave-prone sea states and their probabilities of occurrence. The analysis is based on hindcast data from the North Atlantic, the North Sea, the Norwegian Sea, Nigeria and Australia and supported by numerical simulations performed by the Higher Order Spectral Method (HOSM, West et al. J Geophys Res 92:11803-11824, 1987). The hindcast data have been generated by the wave model WAM. Long-term probabilistic description of significant wave height and spectral peak period is established for the selected locations and probability of occurrence of crossing rogue-wave-prone sea states is indicated. Further, the occurrence of individual rogue waves in low, intermediate and high sea states is also evaluated. The results are discussed from the perspective of design and operations of ships and offshore structures.

  17. Deep-sea soundings

    NASA Astrophysics Data System (ADS)

    Brooks, David A.

    Bathymetric charts for many areas of the ocean are cheap and accurate, and we usually take their availability for granted. In these times of abundant information, it is easy to forget the wonder and excitement of the last century, when mechanical sounding machines revealed for the first time the major features of the ocean depths. Who would not be awed by the graceful sweep of the Blake Plateau or the plunging depths of the Puerto Rico Trench, and who could remain unimpressed by undersea mountain ranges more majestic than any in view? In his 1888 book, entitled Three Cruises of the Blake, Alexander Agassiz has this to say about the spectacular Caribbean bottom topography: Compared to such panoramas the finest views of the range of the Alps sink into insignificance; it is only when we get a view of portions of the Andes from the sea-coastthat we get anything approximating to it in grandeur.

  18. Deep sea cores available

    NASA Astrophysics Data System (ADS)

    Scientists aboard the Glomar Challenger collected a 235-m core of marine sediment specifically for geochemical study. This core, obtained with the hydraulic piston corer from site 532 (leg 75) in the South Atlantic, was frozen immediately upon its retrieval to preserve its organic geochemical properties. Samples from this core are now available to researchers.Site 532 is a reoccupation of deep-sea drilling (DSDP) site 362 of leg 40. The organic carbon content in this bioturbated core ranges between 1 and 6% and appears to fluctuate markedly on a time scale of 20,000-50,000 years. The lowest values occur in deeper sediments, and they generally are higher in younger sediments, reflecting an intensification of upwelling conditions at this location. An organic carbon maximum in upper Pliocene sediments records stronger upwelling conditions during that time.

  19. Fire in the Sea

    NASA Astrophysics Data System (ADS)

    Friedrich, Walter L.

    2000-05-01

    The legend of the lost city of Atlantis has captivated the human imagination for centuries. Did this city actually exist, and, if so, what happened to it? Was it destroyed in the greatest cataclysmic event of the Bronze Age? While the truth behind the legend of Atlantis may never be known, Fire in the Sea tells the story of one of the largest and most devastating natural disasters of classical history that may also hold vital clues to the possible existence and fate of the lost city. In vivid prose, author Walter L. Friedrich describes the eruption of the Greek island of Santorini, or Thera, sometime in the 17th or 16th century BC. This eruption, perhaps one of the largest explosions ever witnessed by humankind, sent a giant cloud of volcanic ash into the air that eventually covered settlements on the island. Friedrich relates how this event forever altered the course of civilization in the region, and inspired a mystery that has fired humanity's imagination ever since. More than 160 elegant, full-color photographs and vivid prose capture the beauty, the geology, archaeology, history, peoples and environmental setting of Santorini. Fire in the Sea will readily appeal to the general reader interested in natural catastrophies as well as the beauty of the region. It will also enchant anyone who has ever dreamt about uncovering the mystery of the legend of Atlantis. Walter Friedrich is currently an associate professor at the Department of Earth Sciences, University of Aarhus, Denmark. He has visited Santorini at least 35 times since 1975 and has published numerous scientific articles in such international journals as Nature, Lethaia, Spektrum der Wissenschaft, and other publications.

  20. Arctic Sea Ice Predictability and the Sea Ice Prediction Network

    NASA Astrophysics Data System (ADS)

    Wiggins, H. V.; Stroeve, J. C.

    2014-12-01

    Drastic reductions in Arctic sea ice cover have increased the demand for Arctic sea ice predictions by a range of stakeholders, including local communities, resource managers, industry and the public. The science of sea-ice prediction has been challenged to keep up with these developments. Efforts such as the SEARCH Sea Ice Outlook (SIO; http://www.arcus.org/sipn/sea-ice-outlook) and the Sea Ice for Walrus Outlook have provided a forum for the international sea-ice prediction and observing community to explore and compare different approaches. The SIO, originally organized by the Study of Environmental Change (SEARCH), is now managed by the new Sea Ice Prediction Network (SIPN), which is building a collaborative network of scientists and stakeholders to improve arctic sea ice prediction. The SIO synthesizes predictions from a variety of methods, including heuristic and from a statistical and/or dynamical model. In a recent study, SIO data from 2008 to 2013 were analyzed. The analysis revealed that in some years the predictions were very successful, in other years they were not. Years that were anomalous compared to the long-term trend have proven more difficult to predict, regardless of which method was employed. This year, in response to feedback from users and contributors to the SIO, several enhancements have been made to the SIO reports. One is to encourage contributors to provide spatial probability maps of sea ice cover in September and the first day each location becomes ice-free; these are an example of subseasonal to seasonal, local-scale predictions. Another enhancement is a separate analysis of the modeling contributions. In the June 2014 SIO report, 10 of 28 outlooks were produced from models that explicitly simulate sea ice from dynamic-thermodynamic sea ice models. Half of the models included fully-coupled (atmosphere, ice, and ocean) models that additionally employ data assimilation. Both of these subsets (models and coupled models with data assimilation) have a far narrower spread in their prediction, indicating that the results of these more sophisticated methods are converging. Here we summarize and synthesize the 2014 contributions to the SIO, highlight the important questions and challenges that remain to be addressed, and present data on stakeholder uses of the SIO and related SIPN products.

  1. TOC and satellite-sensed chlorophyll and primary production at the Arctic Front in the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Brsheim, Knut Yngve; Milutinovi?, Svetlana; Drinkwater, Kenneth F.

    2014-11-01

    In the Arctic Front region south of Jan Mayen, vertical profiles of Total Organic Carbon (TOC) and hydrographic variables were measured during 3 weeks in June 2007. From time series of satellite-sensed chlorophyll, it was determined that the field studies took place in the aftermath of the culmination of the spring bloom, both on the Arctic (Icelandic Sea) and Atlantic (Norwegian Sea) sides of the Arctic Front. TOC in the upper 50 m was on average 60.9 7.6 ?M C on the Arctic side and 62.3 6.8 ?M C on the Atlantic side. Average in situ fluorescence was higher on the Atlantic side. Annual primary production calculated from satellite imagery showed no enhancement at the Front. To place the Frontal measurements in a larger perspective, satellite imagery over the entire Nordic (Greenland-Icelandic-Norwegian) Seas between 1998 and 2012 were studied. They showed that north of Jan Mayen the spring blooms normally last longer and culminate later with a higher concentration of chlorophyll at the peak in the colder water on the west side of the Front than in the Norwegian Sea. In the year of our expedition, the maximal concentration of satellite-sensed chlorophyll at spring bloom was three times higher in the central Greenland Sea than in the Norwegian Sea. Along the Arctic Front the maximal concentration of satellite sensed chlorophyll was always lower than in the central basins both west and east of the Front. The ordinal date of maximal spring bloom concentration of chlorophyll was negatively correlated with the maximal spring bloom chlorophyll concentration in the Norwegian and Icelandic Seas, but uncorrelated in the Greenland Sea. Interannual variation of primary production and maximal chlorophyll concentration was larger in the Greenland Sea then in the Icelandic and Norwegian Seas and we hypothesize that some of this variation is influenced by difference in energy efficiency between phototrophs and heterotrophs at low temperatures.

  2. Contrasts in Arctic shelf sea-ice regimes and some implications: Beaufort Sea versus Laptev Sea

    USGS Publications Warehouse

    Reimnitz, E.; Dethleff, D.; Nurnberg, D.

    1994-01-01

    The winter ice-regime of the 500 km) from the mainland than in the Beaufort Sea. As a result, the annual freeze-up does not incorporate old, deep-draft ice, and with a lack of compression, such deep-draft ice is not generated in situ, as on the Beaufort Sea shelf. The Laptev Sea has as much as 1000 km of fetch at the end of summer, when freezing storms move in and large (6 m) waves can form. Also, for the first three winter months, the polynya lies inshore at a water depth of only 10 m. Turbulence and freezing are excellent conditions for sediment entrainment by frazil and anchor ice, when compared to conditions in the short-fetched Beaufort Sea. We expect entrainment to occur yearly. Different from the intensely ice-gouged Beaufort Sea shelf, hydraulic bedforms probably dominate in the Laptev Sea. Corresponding with the large volume of ice produced, more dense water is generated in the Laptev Sea, possibly accompanied by downslope sediment transport. Thermohaline convection at the midshelf polynya, together with the reduced rate of bottom disruption by ice keels, may enhance benthic productivity and permit establishment of open-shelf benthic communities which in the Beaufort Sea can thrive only in the protection of barrier islands. Indirect evidence for high benthic productivity is found in the presence of walrus, who also require year-round open water. By contrast, lack of a suitable environment restricts walrus from the Beaufort Sea, although over 700 km farther to the south. We could speculate on other consequences of the different ice regimes in the Beaufort and Laptev Seas, but these few examples serve to point out the dangers of exptrapolating from knowledge gained in the North American Arctic to other shallow Arctic shelf settings. ?? 1994.

  3. The cause of Barents Sea biomass dynamics

    NASA Astrophysics Data System (ADS)

    Yndestad, Harald

    2004-01-01

    The fluctuations of the biomasses in the Barents Sea have been poorly understood and caused problems in biomass management. Better long-term forecasting is thus crucial for an economical and sustainable utilization of the biomass. The present paper presents a wavelet analysis of the Kola temperature series and the biomass time series of Barents Sea Shrimp ( Pandalus borealis), Barents Sea capelin ( Mallotus villosus), Norwegian spring spawning herring ( Clupea harengus), Northeast Arctic cod ( Gadus morhua), and Northeast Arctic haddock ( Melanogrammus aeglefinus). The wavelet shows a close relation between the 18.6-year lunar nodal tide and dominant temperature cycles in the Kola temperature series. It also shows that all biomass time series are correlated to dominant cycles of 18.6/3=6.2, 18.6 and 3?18.6=55.8 years in the Kola section. This indicates that fluctuations of the temperature and the biomass in the Barents Sea are a deterministic process caused by the lunar nodal cycle. The close relation to the stationary 18.6-year lunar tide opens new possibilities for better forecasting and long-term management. The deterministic relation between biomass growth and the Kola cycles opens a possibility of more optimal management in short-term periods of 6 years, medium-term management of 18 years and long-term management of 55-75 years. The stationary biomass cycles can be represented by a simple phase-clock which indicates the current state of the biomass. This method represents a new possibility of long-term biomass forecasting.

  4. Polarimetric backscattering from sea ice

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Kwok, R.; Yueh, S. H.

    1993-01-01

    Polarimetric backscattering from sea ice is presented. Theoretical models for backscattering are first presented for various ice types. Then, theoretical results are compared with experimental data for new thin ice, first-year ice, and multi-year ice. Sea ice is modeled as a layer medium containing random scatterers and rough interfaces. For multi-year sea ice with snow cover, the sea ice layer is modeled as an ice background with embedded spheroidal air bubbles and the snow layer as air with ice grains. The hummocky topography on multi-year ice is characterized by a Gaussian distribution which has an averaging effect on backscattering coefficients. First-year sea ice is described by an ice medium hosting ellipsoidal brine inclusions. These inclusions are oriented preferentially in the vertical direction due to the columnar structure of first-year sea ice. Azimuthally, the orientation of the brine pockets are random corresponding to the random c-axes in sea ice, unless the axes are oriented by sea currents. For thin ice in newly opened leads, it has been observed that there exists a thin brine layer with very high salinity on the top surface of the new ice. This brine layer is depicted as a medium with high permittivity which can significantly affect electromagnetic scattering signatures from the lower thin ice layer, with a higher fractional volume of brine inclusions due to higher salinity as compared to thick first-year sea ice. The rough medium interfaces are described as Gaussian rough surfaces characterized by root-mean-square heights and surface correlation lengths. The contribution from rough surface, calculated under the Kirchhoff approximation or small perturbation method, is assumed to be independent from volume scattering. The total loss including absorption and scattering losses in the scattering media is represented by the imaginary part of effective permittivity obtained from the strong fluctuation theory. The polarimetric scattering coefficients for different ice types are then derived under the distorted Born approximation.

  5. Sea Star Succumbing to Sea Star Wasting Disease

    USGS Multimedia Gallery

    Unlike their smiling cartoon brethren on television, since 2013, real-life sea stars have been suffering from a wasting disease epidemic in which they lose limbs and literally disintegrate in a matter of days. ...

  6. Tortuosity of the Antarctic Sea Ice over the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Beard, J.; Heinrichs, J. F.

    2011-12-01

    The objective of the research was to mathematically characterize the edge of the Antarctic sea ice in the Weddell Sea. Because the sea ice may reflect processes involved in the atmosphere and ocean near the ice edge, it may suggest broader changes on the ice. The chosen method was to compare the tortuosity of the edge over time and across seasons. Because the sea ice may reflect processes involved in the atmosphere and ocean near the ice edge, it may suggest broader changes on the ice. Throughout the research, the shapefiles for the Antarctic sea ice were collected from the National Snow and Ice Data Center website and the coordinates were extracted using an add-in for the MapWindow GIS. These points were then put into Excel separated by year and then the distance factor (an approximation to the tortuosity) was calculated and compared by month over time. Preliminary data has shown that the closer to the winter months, the higher the tortuosity. Statistical analysis has shown that there is no clear relationship between tortuosity and the area of the sea ice, and the tortuosity exhibits a weak negative trend over the past 32 years.

  7. Zooplankton data: Vertical distributions of zooplankton in the Norweigian and Greenland Seas during summer, 1989

    SciTech Connect

    Lane, P.V.Z.; Smith, S.L.; Schwarting, E.M.

    1993-08-01

    Recent studies of zooplankton populations in the Greenland Sea have focused on processes at the Marginal Ice Zone (MIZ) and the areas immediately adjacent to it under the ice and in open water. These studies have shown a relatively short period of intense secondary productivity which is closely linked temporally and spatially to phytoplankton blooms occurring near the ice edge in spring and early summer. During the summer of 1989 we participated in a project focusing on benthic and water column processes in the basins of the Norwegian and Greenland Seas. This study allowed us to compare biological processes at the MIZ with those occurring in the open waters of the Greenland Sea, and to compare processes at both of these locations with those in the Norwegian Sea. The data presented in this report are the results of zooplankton net tows covering the upper 1000 meters of the water column over the Norwegian Sea basin and the Greenland Sea basin, and the upper 500 meters of open water adjacent to the MIZ in the Greenland Sea. Sampling was conducted between 12 and 29 July 1989.

  8. A Can of Sea Worms

    ERIC Educational Resources Information Center

    Zinn, Donald J.

    1977-01-01

    A comprehensive discussion of the free-living worms that inhabit the beaches and subtidal bottoms of the Cape Cod shoreline is presented. Methods for the location, collection, preservation, and identification of sea worms are identified. (BT)

  9. Doppler characteristics of sea clutter.

    SciTech Connect

    Raynal, Ann Marie; Doerry, Armin Walter

    2010-06-01

    Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

  10. An empirically derived inorganic sea spray source function incorporating sea surface temperature

    NASA Astrophysics Data System (ADS)

    Salter, M. E.; Zieger, P.; Acosta Navarro, J. C.; Grythe, H.; Kirkevåg, A.; Rosati, B.; Riipinen, I.; Nilsson, E. D.

    2015-10-01

    We have developed an inorganic sea spray source function that is based upon state-of-the-art measurements of sea spray aerosol production using a temperature-controlled plunging jet sea spray aerosol chamber. The size-resolved particle production was measured between 0.01 and 10 μm dry diameter. Particle production decreased non-linearly with increasing seawater temperature (between -1 and 30 °C) similar to previous findings. In addition, we observed that the particle effective radius, as well as the particle surface, particle volume and particle mass, increased with increasing seawater temperature due to increased production of particles with dry diameters greater than 1 μm. By combining these measurements with the volume of air entrained by the plunging jet we have determined the size-resolved particle flux as a function of air entrainment. Through the use of existing parameterisations of air entrainment as a function of wind speed, we were subsequently able to scale our laboratory measurements of particle production to wind speed. By scaling in this way we avoid some of the difficulties associated with defining the "white area" of the laboratory whitecap - a contentious issue when relating laboratory measurements of particle production to oceanic whitecaps using the more frequently applied whitecap method. The here-derived inorganic sea spray source function was implemented in a Lagrangian particle dispersion model (FLEXPART - FLEXible PARTicle dispersion model). An estimated annual global flux of inorganic sea spray aerosol of 5.9 ± 0.2 Pg yr-1 was derived that is close to the median of estimates from the same model using a wide range of existing sea spray source functions. When using the source function derived here, the model also showed good skill in predicting measurements of Na+ concentration at a number of field sites further underlining the validity of our source function. In a final step, the sensitivity of a large-scale model (NorESM - the Norwegian Earth System Model) to our new source function was tested. Compared to the previously implemented parameterisation, a clear decrease of sea spray aerosol number flux and increase in aerosol residence time was observed, especially over the Southern Ocean. At the same time an increase in aerosol optical depth due to an increase in the number of particles with optically relevant sizes was found. That there were noticeable regional differences may have important implications for aerosol optical properties and number concentrations, subsequently also affecting the indirect radiative forcing by non-sea spray anthropogenic aerosols.

  11. 50 CFR 648.11 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Atlantic deep-sea red crab; or a moratorium permit for summer flounder; to carry a NMFS-certified fisheries... Atlantic deep-sea red crab permit, a skate permit, or a tilefish permit, if requested by the sea sampler... flounder, scup, black sea bass, bluefish, spiny dogfish, Atlantic herring, Atlantic deep-sea red...

  12. North Sea platforms revamped

    SciTech Connect

    O'Hare, J.

    1999-12-01

    Many of the early North Sea platforms are reaching their end-of-field life. Most are still equipped with their original drilling package. In a few cases the package has either been removed or decommissioned. The early installations were designed for much simpler and less demanding wells than the horizontal, extended-reach or designer wells common today. Extended-reach wells now can be drilled realistically from ageing platforms, without incurring massive capital expenditure. This can be achieved using the existing drilling package to the limit of its capabilities and supplementing where necessary with relatively minor upgrades or the use of temporary equipment. Drilling even a few more wells from existing platforms not only prolongs field life, it enables any surplus processing capacity to be made available to develop near-field potential with extended-reach drilling (ERD) or by tying back subsea satellite wells, or for processing third-party fluids. The paper describes well design, surface equipment, mud pumps, shakers and solids control equipment, drill cuttings disposal systems, derrick and hoisting system, top drive and drillstring, downhole equipment, well planning, casing wear, logistics, rig preparations, and ERD vs. subsea tie-backs.

  13. Exploring the deeper seas

    SciTech Connect

    Witt, R.R., Jr.

    1980-06-05

    The history, current status, and economics of offshore exploration for crude oil and natural gas in water depths over 600 ft since it became a reality in 1965 are reviewed. Development has not progressed as originally anticipated, and only three deepwater areas - the Gulf of Mexico, California, and the North Sea - account for 54% of all wells drilled but have less than 10% of the world's prospective deepwater acreage. Deepwater drilling has barely begun - only one deepwater well has been drilled per 17 million prospective deepwater acres. To date expenditures for deepwater drilling have been uneconomical; however, the tension leg platform is seen as possibly an economical means of producing hydrocarbons from deepwater areas. The enormous front-end expenditure has greatly limited the development of deepwater production. Only the largest oil companies can enter into the risky and very capital-intensive ventures, and even the largest companies can only afford to develop the largest fields which offer the best potential for return of capital. Increased oil prices and stable or good economic conditions of the major industralized nations will probably impact the volume of petroleum consumed in such a way as to render development of deepwater areas economical in the future. (BLM)

  14. Applied Sea Ice Research

    NASA Astrophysics Data System (ADS)

    Lset, S.

    2009-04-01

    In the late 1960s oil and gas development became an issue in the northern coastal areas of Alaska and Canada. More lately this has also become an issue in the Euroasian Arctic with the Barents and Kara Seas as example on where offshore hydrocarbon production now is being planned. In such waters the key questions prior to a development are related to water depths at the site and in case of ice, how frequent and what type of ice features will be met. Especially the ice conditions and knowledge about them are very decisive for the field development solutions to be chosen. The paper will highlight examples on development solutions where the ice conditions have played a paramount role in the field development plans. An example is the consequences of iceberg threaten in an area and the effect sudden changes in ice drift directions may have on the exploration and drilling solutions chosen. The paper will also discuss how to derive design ice actions values for such waters including scaling from nature to model ice basins.

  15. A Sea of Lava

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Islands of older high-standing terrain rise above a sea of relatively young, platy lava flows between two of the largest volcanoes in the solar system.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 10.6, Longitude 158.5 East (201.5 West). 19 meter/pixel resolution.

  16. Arctic Sea Ice Model Sensitivities

    NASA Astrophysics Data System (ADS)

    Peterson, K. J.; Bochev, P.; Paskaleva, B.

    2010-12-01

    Arctic sea ice is an important component of the global climate system and, due to feedback effects, the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice state to internal model parameters. A new sea ice model that holds some promise for improving sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of this MPM sea ice code and compare it with the Los Alamos National Laboratory CICE code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness,and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U. S. Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94-AL85000.

  17. Offshore northern sea case histories of the environmentally friendly testing vessel, the ``Crystal Sea``

    SciTech Connect

    Tjelta, O.; Ashwell, C.; Hilmarsen, G.; Taylor, R.W.

    1995-12-01

    One of the problems that surfaces during offshore well test operations, stimulations, and routine workovers has been the discharges that are made into the air and sea, and in particular, the possible formation of dioxins during the combustion process. Since these operations and tests have normally been performed by mobile drilling rigs that do not have storage capacity, oil and gas sequestered during performance of the procedures are burned off from the rig flarebooms. Another major problem during well testing has been the incapability of the flare to operate at high flow rates. Since the burning process slows down the pace of a test and does not allow the well to be tested under full flow, valuable information about the well cannot be determined. In light of the economic and regulatory changes occurring in today`s oil and gas industry, the justification for development of a cost-effective, environmentally-safe alternative to flaring hydrocarbons was certainly indicated. This paper will discuss the well test vessel, ``Crystal Sea,`` and the initial two jobs on the Statfjord North Satellite Field in the Norwegian sector of the North Sea. The success of these jobs confirms that the Crystal Sea can provide an alternative to flaring that reduces the degree of pollutants discharged from oil rigs, and at the same time, can salvage the usable oil. The sale of the salvaged oil, which would normally be lost during the flaring process, often can generate sufficient economic return to pay for the vessel. ``Crystal Sea`` is capable of receiving products at approximately twice the flow rate as is possible with conventional surface test equipment from a rig. This increased flow rate not only improves the accuracy of the technical information obtained from the well test but also provides valuable tools for improved reservoir management.

  18. Variability patterns of the general circulation and sea water temperature in the North Sea

    NASA Astrophysics Data System (ADS)

    Mathis, M.; Elizalde, A.; Mikolajewicz, U.; Pohlmann, T.

    2015-06-01

    This study investigates patterns of spatio-temporal variability in the North Sea and their major driving mechanisms. Leading variability modes of the general circulation and sea water temperature are extracted from model results by means of Empirical Orthogonal Functions (EOF) analysis. The model results originate from an uncoupled simulation with the global ocean model MPIOM, forced with ERA40 reanalysis data at the air-sea interface. For this regional model study, MPIOM has been run with a stretched grid configuration enabling higher horizontal resolution in the Northwest European Shelf and North Atlantic ocean. The analysis is applied to interannual variabilities of winter and summer separately. The results indicate that on seasonal scales the leading variability mode of the general circulation affects the entire North Sea, accompanied by significant inflow anomalies through the Fair-Isle Passage. Correlations of the corresponding Principal Component (PC) with wind density functions reveal the circulation anomalies to coincide with westerly and south-westerly wind anomalies. The second mode describes circulation anomalies along the Norwegian Trench and English Channel, which correlate with north-westerly wind anomalies caused by variations in large-scale atmospheric pressure areas centered over the British Isles. For sea water temperature, distinct variability patterns are induced by variable surface heat fluxes, vertical mixing, and variable advective heat fluxes. The first mode of both the general circulation and water temperature in winter mainly represents the response to atmospheric variations in the North Atlantic Oscillation (NAO). However, the higher modes account for such variabilities that cannot be explained by the NAO. As a consequence of the integrated effects of the different variability modes on the circulation system and heat content, local correlations of the NAO with volume transports and water temperature are weakened in the regions of Atlantic inflow.

  19. DESERVE - Dead Sea Research Venue

    NASA Astrophysics Data System (ADS)

    Mohsen, A.; Weber, M. H.; Kottmeier, C.

    2013-12-01

    DESERVE 'Dead Sea Research Venue' focuses on the Dead Sea region as it is a unique environment and may be considered as one of the most inspiring natural laboratories on Earth. The Dead Sea Region is an exceptional ecosystem whose seismic activity has influenced all facets of the development, from ground water availability to human evolution. DESERVE addresses three grand challenges: Environmental Risks, Water Availability, Climate Change and comprises long term monitoring of geophysical parameters, studies of coupled processes in the atmosphere, hydrosphere and lithosphere as well as modeling of prediction and remediation strategies of geogenic risks. The Dead Sea has been selected for this integrated approach because it constitutes an outstanding 'natural laboratory' to study these phenomena, as - all 3 challenges are critical in this region. - the region is especially sensitive to climate change and human influences such as ground and surface water over-exploitation for agriculture and industrial purposes. - environmental processes are subject to boundary conditions that cannot be found elsewhere on Earth - understanding their interactions and the future evolution of the whole Dead Sea region are of key importance for economic development in peaceful cooperation. Results obtained in the Dead Sea region are also of prototype relevance for other (semi)-arid terminal basins of the world.

  20. Nordic Sea Level - Analysis of PSMSL RLR Tide Gauge data

    NASA Astrophysics Data System (ADS)

    Knudsen, Per; Andersen, Ole

    2015-04-01

    Tide gauge data from the Nordic region covering a period of time from 1920 to 2000 are evaluated. 63 stations having RLR data for at least 40 years have been used. Each tide gauge data record was averaged to annual averages after the monthly average seasonal anomalies were removed. Some stations lack data, especially before around 1950. Hence, to compute representative sea level trends for the 1920-2000 period a procedure for filling in estimated sea level values in the voids, is needed. To fill in voids in the tide gauge data records a reconstruction method was applied that utilizes EOF.s in an iterative manner. Subsequently the trends were computed. The estimated trends range from about -8 mm/year to 2 mm/year reflecting both post-glacial uplift and sea level rise. An evaluation of the first EOFs show that the first EOF clearly describes the trends in the time series. EOF #2 and #3 describe differences in the inter-annual sea level variability with-in the Baltic Sea and differences between the Baltic and the North Atlantic / Norwegian seas, respectively.

  1. Total and organic mercury in Barents sea pelagic fish

    SciTech Connect

    Joiris, C.R.; Ali, I.B.; Hoisbeek, L. Bossicart, M.; Tapia, G.

    1995-11-01

    One of the main questions, when studying mercury levels in natural samples, is to define how far the measured concentrations correspond to natural- or background-levels or to actual contamination due to human activities. To establish background pristine levels of Hg in the marine environment, areas of very low human activities are often proposed. Arctic and Antarctic waters, together with deep oceans waters, are best suited and provide themselves for such studies. Barents Sea areas were used in this study, even if the existence of an important atmospheric transport of Hg probably caused an increase of Hg levels at a global scale. Instead of analyzing mercury from the very low concentrations in sea water, it is much easier to identify it from the higher concentrations which organisms, used as bioindicators, have built up in their tissues. By using these bioindicators to study the bioavailable fraction of the stable residues, one also integrates small scale temporal and spatial variations. Pelagic fish were used in this work to study the ecotoxicology of Hg in the Barents Sea. This study has been made possible due to recent access of the Barents Sea to western scientists and it is to serve as a complement to existing studies by the same team in the Greenland and Norwegian seas, and the southwestern part of the Barents Sea. 19 refs., 4 figs., 2 tabs.

  2. Mesoscale structures in the Subarctic Seas - observations and modelling

    NASA Astrophysics Data System (ADS)

    Walczowski, W.; Maslowski, W.

    2003-04-01

    Scientists from IO PAS have investigated the sub-arctic seas since 1989. In this study we present data collected by the IO PAS in contribution to VEINS project as well as from the other cruises conducted by R.V. Oceania in the Barents, Norwegian and Greenland seas. Observed mesoscale structures will be compared with results from two high-resolution models of the Pan-Arctic region forced with realistic atmospheric fields. The first model is configured at 1/6°(~18 km) and 30-layer grid and the second at 1/12° (~9 km) and 45-layer grid. Both models are developed at the Naval Postgraduate School, Monterey. Based on in situ measurements and model output, we specify regions of high mesoscale activity, which exist mainly along the Barents slope, in the area west of Spitsbergen and along the Arctic Front, separating water of Atlantic origin from the Greenland Sea Gyre. A comparison between current patterns, total kinetic energy (TKE) and eddy kinetic energy (EKE) calculated from the models and from in situ data will be presented. We will analyse observed mesoscale structures including frontal meanders and intrusions, cyclonic and anticyclonic eddies, and dense water plumes. Selected phenomena will be compared with modelled structures. Investigations of the Arctic Front show that mesoscale eddies and intrusions play an important role in the cross-frontal volume, salt and heat exchanges. Anticyclonic eddies originating from the frontal meanders carry considerable volume of Atlantic Water into the Greenland Sea. The transport of Atlantic Water from the Norwegian Sea into the Greenland Sea Gyre will be analysed based on field data and eddy-permitting model output. Anticyclonic eddies originating to the west of Spitsbergen play an important role in the recirculation of Atlantic Water in Fram Strait. Observed and modelled processes and pathways of the recirculation of Atlantic Water will be presented.

  3. Seismic investigations in the Weddell Sea Embayment

    NASA Astrophysics Data System (ADS)

    Haugland, Kristen; Kristoffersen, Yngve; Velde, Anders

    1985-04-01

    Seismic multi-channel data collected during Norwegian Antarctic Research Expeditions in 1976-1977 and 1978-1979 outline aspects of the Cenozoic depositional environment in the Weddell Sea Embayment. Acoustic basement, probably representing the East Antarctic craton, is exposed in a 50-100 km wide swath along the ice barrier between 78°S-75.5°S on the eastern side of the Crary Trough. The shelf prograded westward and northward from the craton into a subsiding basin colinear with the Transantarctic Mountain Range. Measured sediment thicknesses exceed 5 km. During middle and late Tertiary times a submarine fan complex—the Crary Fan—developed on the southeastern margin of the Weddell Sea Embayment. The glacially eroded Crary Trough is located at the contact between the craton and a sedimentary basin to the west. The entire sedimentary section is undisturbed by faulting or folding, which indicates that any movements related to Cenozoic uplift of the Trans-Antarctic Mountains and/or relative motion of East Antarctica had little effect in the area north of the Filchner Ice Shelf east of 41°W.

  4. Variability of the Atlantic inflow to the Nordic Seas and its causes inferred from observations of sea surface height

    NASA Astrophysics Data System (ADS)

    Richter, K.; Segtnan, O. H.; Furevik, T.

    2012-04-01

    We investigate the potential to use sea surface height observed with satellites and tide gauges to explore and to estimate the variability of volume transport of Atlantic water to the Nordic Seas. It is shown that the variability of the Atlantic inflow to the Nordic Seas over the Iceland Faroe Ridge (Faroe Current) primarily responds to an oceanic regime dominated by steric height changes in the interior Nordic Seas. In contrast, variations in the Norwegian Atlantic Slope Current measured at the Sviny section are largely driven by direct wind forcing. Using linear regression analysis, volume transports anomalies were successfully modeled from the leading modes of altimeter-derived sea surface height and reconstructed back in time using sea surface height observations from tide gauges. The reconstructions explain 22% and 38% of the observed variability in the Faroe and Sviny currents, respectively. For the Sviny Current, the reconstruction indicates that the volume transport variability is typically of the order 1 Sv. High inflow around 1983 and low inflow around 1987 coincide with times when respectively warm and cold anomalies passed through the system.

  5. Past and present Aral Sea

    NASA Astrophysics Data System (ADS)

    Dukhovniy, Viktor; Stulina, Galina; Eshchanov, Odylbek

    2013-04-01

    The tragedy of disappearing of Aral Sea is well known to the World. Before and after collapse of Soviet Union, a huge quantity of scientific and popular editions described with grief the situation around the Aral Sea. After the NIS states became independent, World Bank, UNDP, UNEP in proper competition with each other had provided some assessment of the situation through presentation of some small and medium grants, but after 2000, the local population remained alone with own problems. Although on the eyes of the present generation a unique transformation of great water body into deserts took place, the global scientific community did not find forces and financing for real and detail investigation of the processes accompanying the Sea shrinking and land formation. We should acknowledge and give big respect to NATO, later to German Government that through GTZ (now GIZ) - German International Collaboration Agency - and GFZ (Potzdam) paid attention to this area of environment crisis and organized scientific and protective design in the so-called Priaralie - the territory around the drying Sea and delta of the two rivers - Amudarya and Syrdarya. Thank to this assistance, the local specialists in collaboration with limited a number of foreign scientists (N.Aladin, P.Zavialov, Joop de Schutter, Hans Wilps, Hedi Oberhansli) organized significant works for detail socioeconomic, ecological and hydrological assessment situation in Priaralie and on the Aral sea coast. On this base, Ministry of Agriculture and Water resources of Uzbekistan and State Committee of Water resources of Kazakhstan developed a plan of rehabilitation of Amudarya and Syrdarya deltas and started implementation of these projects. If Kazakh water authority moved ahead in wetland restoration faster, a forestation of delta and drying bed of Aral Sea got big success in Uzbek territory. 244 thousands hectares of saxsaul and tamarix were planted for protection of the Priaralie. By request of GTZ SIC, ICWC organized in 2005-2009 sixth expeditions for complex remote sensing and ground investigations Aral Sea former bottom that were complemented in 2010 -2011 by two expeditions with GFZ. As a result, the landscape, soils and environment mapping was done with determination of ecologically unstable zones and assessment total change of lands situation compared with the pre-independence time. Moreover - methodic of monitoring water, environment and hydro geological indicators on the all deltas area was elaborated, organized its testing and combined with remote sensing data on Amudarya delta for 2009-2012. It permits to SIC ICWC to organize systematic permanent (decadal) monitoring and recording of size, volume and level of water in Aral Sea. Since the beginning of regular observations over the Aral Sea level, 2 periods can be emphasized: 1. Conditionally natural period - 1911-1960 - characterized by a relatively stable hydrological regime, with fluctuations in the level around 53 m and the range of inter-annual fluctuations at no more than 1 m., when the sea received annually about a half of the run-off in the Syrdarya and Amudarya Rivers, i.e. 50-60 km3/yr. 2. Intensive anthropogenic impact period - since the 1960s, a vast extension of irrigable land was carried out in Central Asia that resulted in intensive diversion of river run-off. Since then, the sea level has been falling steadily, causing a dramatic reduction in the water surface area, a decrease in water volume and depths, great changes in shoreline configuration and an expansion of the desert areas adjacent to the Aral Sea. From 1960-1985, when the sea was an integral water body, slight lowering in the sea level took place until the 1970s, when the sea-level decreased with the mean level lowering 1 m. The desiccation process accelerated visibly from the mid 1970s. In 1975-1980, the level decreased by 0.65 m a year on average. Moreover, the level dropped greatly, when the run-off of the Amudarya did not reach the Aral Sea any more (1980-1990). Kokaral was the first of the large islands becoming a peninsula, separating the Small Aral Sea in the north-east by joining the shoreline in the west. By 1986, the peninsula practically detached the small Aral Sea from the large Aral Sea, leaving only a narrow flow passage in the east. Since that time, the hydrological regimes of the Small and Large Seas have become separated. The construction of Kokaral dam in Kazakhstan, 12 km long and 8 m high, then completely separated the small Aral Sea from the large Aral Sea and changed the hydrological regimes of the water bodies. Level of this part of Sea became from this moment permanently higher than in the large Aral Sea on 42 m a.s.l. The eastern part of the sea, where the bed is much shallower and the slope is gentler is more subjected to shrinking then the western part. 2005 year became threshold, from which Eastern Aral Sea began new story - deviation from almost empty water body to almost 4 meters depth. Present assessment of water balance of Aral Sea and delta at whole dependent from delivery water river and drainage flow through control section of Samanbay on the Amudarya and some cross sections on the enter main collectors to the delta boundary. These hydrological characteristics accepted on the base of information from BWO Amudarya and our monitoring of allocation of different waters on the delta. Water volume and water surface area of Eastern and Western Aral Sea bowls were definite on the result RS data from Landsat. Bathymetric curves gave ability to assess dynamic levels of Seas. After series of enough water years 2002 - 2005 with average water income to south Priaralie 12.5 km3 period of water scarce years lead to sharp decrease of surface water area of the Eastern bowl from 1010,5 th.ha on average on two time with failure of level from 31,1 m up to average 28,5 m. But phase of permanent reducing all indicators water body changed in 2008 on deviation in range from 26.3 m to 29.5 m. Some time sharp changes in the level of water in 2.0 m take place in time one year. These changes same as degree of deltas' watering depends fully from inflow water to boundary of deltas. At the same time, the Western bowl remained more or less stable and without direct flow of surface water supported own water stability based on balance between evaporation and precipitation plus presumably the inflow of deep ground water.

  6. Magnetohydrodynamic sea water propulsion

    SciTech Connect

    Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

    1991-12-31

    An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

  7. Magnetohydrodynamic sea water propulsion

    SciTech Connect

    Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

    1991-01-01

    An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

  8. SeaWinds - Greenland

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The frequent coverage provided by NASA's SeaWinds instrument on the QuikScat satellite provides unprecedented capability to monitor daily and seasonal changes in the key melt zones of Greenland, which is covered with a thick ice sheet that resulted from snow accumulating over tens of thousands of years. The thickness of the snow layers reveals details about the past global climate, and comparing snow accumulation and snow melting can provide insight into climate change and global warming. In particular, the extent of summer melting of snow in Greenland is considered a sensitive indicator of global change.

    Earlier scatterometer data has suggested that Greenland has experienced significantly more melting in recent years. This figure compares the melting observed over 15 days during July 1999 in Greenland. The red areas around the central blue and white areas are the main melt zones and have lower radar back scatter because of water on the surface that saturates the surface snow. As the days warm up, the melt extent dramatically increases. Comparing this data with computer models and past scatterometer data will help scientists evaluate the inter-annual variability of the melting as a step toward understanding potential climate change.

    The world's large ice sheets in Greenland and Antarctica act as vast storehouses of freshwater. Summer season melting releases large quantities of freshwater into the ocean, and year-to-year variations can have a significant impact on global sea level. Furthermore, long-term changes in the patterns and extent of melting on the large ice sheets reflect the effects of climate variability; thus Greenland is considered a sensitive indicator of global warming.

    Satellite microwave radars are extremely sensitive to melting and can provide the only effective means of accurately measuring the year-round picture of the extent and variability in ice sheet melting. Daily mean images were produced from QuikScat data collected over the Greenland ice sheet at the height of the present summer melt period. In the top row, four images are shown at intervals of 5 days, for (a) day 203, (b) 208,(c) 213, and (d) 218 in 1999. Blue and white colors indicate surfaces which are cold and dry, while read and black indicate wet snow surfaces experiencing melting. The coastal regions are lower in elevation and begin to melt first. As summer progresses, the area of melting expands inland and northwards along the western coast of Greenland as air temperatures warm. A large pale and dark blue region in the central, high-elevation part of the ice sheet survives each summer without experiencing any melting. This is known as the dry snow region, and its area is a measure of the stability of the central part of the ice sheet. The line dividing the melt area and the dry snow is very sensitive to climate conditions and monitoring this line will help scientists determine whether the Earth's climate is changing.

    The lower series of four images shows the daily variability in the radar data within each image. White patches in these images identify regions where the most rapid changes are taking place. Air temperature and precipitation variations are responsible for the patterns, with the greatest impact over the southern tip of Greenland occurring from storms originating over the Atlantic. Note that the red areas of central and northern Greenland experience much smaller or slower changes, with the central ice sheet showing little change during this summer period.

    With its frequent coverage, the SeaWinds instrument is a power and unique tool for monitoring the health of the large ice sheets. The continuing time-series of data is a valuable contribution to assessments of the effects and impact of global change in the polar regions.

    NASA's Earth Science Enterprise is a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system. JPL is a division of the California Institute of Technology, Pasadena, CA.

  9. SeaWinds - Greenland

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The frequent coverage provided by NASA's SeaWinds instrument on the QuikScat satellite provides unprecedented capability to monitor daily and seasonal changes in the key melt zones of Greenland, which is covered with a thick ice sheet that resulted from snow accumulating over tens of thousands of years. The thickness of the snow layers reveals details about the past global climate, and comparing snow accumulation and snow melting can provide insight into climate change and global warming. In particular, the extent of summer melting of snow in Greenland is considered a sensitive indicator of global change.

    Earlier scatterometer data has suggested that Greenland has experienced significantly more melting in recent years. This figure compares the melting observed over 15 days during July 1999 in Greenland. The red areas around the central blue and white areas are the main melt zones and have lower radar back scatter because of water on the surface that saturates the surface snow. As the days warm up, the melt extent dramatically increases. Comparing this data with computer models and past scatterometer data will help scientists evaluate the inter-annual variability of the melting as a step toward understanding potential climate change.

    The world's large ice sheets in Greenland and Antarctica act as vast storehouses of freshwater. Summer season melting releases large quantities of freshwater into the ocean, and year-to-year variations can have a significant impact on global sea level. Furthermore, long-term changes in the patterns and extent of melting on the large ice sheets reflect the effects of climate variability; thus Greenland is considered a sensitive indicator of global warming.

    Satellite microwave radars are extremely sensitive to melting and can provide the only effective means of accurately measuring the year-round picture of the extent and variability in ice sheet melting. Daily mean images were produced from QuikScat data collected over the Greenland ice sheet at the height of the present summer melt period. In the top row, four images are shown at intervals of 5 days, for (a) day 203, (b) 208,(c) 213, and (d) 218 in 1999. Blue and white colors indicate surfaces which are cold and dry, while read and black indicate wet snow surfaces experiencing melting. The coastal regions are lower in elevation and begin to melt first. As summer progresses, the area of melting expands inland and northwards along the western coast of Greenland as air temperatures warm. A large pale and dark blue region in the central, high-elevation part of the ice sheet survives each summer without experiencing any melting. This is known as the dry snow region, and its area is a measure of the stability of the central part of the ice sheet. The line dividing the melt area and the dry snow is very sensitive to climate conditions and monitoring this line will help scientists determine whether the Earth's climate is changing.

    The lower series of four images shows the daily variability in the radar data within each image. White patches in these images identify regions where the most rapid changes are taking place. Air temperature and precipitation variations are responsible for the patterns, with the greatest impact over the southern tip of Greenland occurring from storms originating over the Atlantic. Note that the red areas of central and northern Greenland experience much smaller or slower changes, with the central ice sheet showing little change during this summer period.

    With its frequent coverage, the SeaWinds instrument is a power and unique tool for monitoring the health of the large ice sheets. The continuing time-series of data is a valuable contribution to assessments of the effects and impact of global change in the polar regions.

    NASA's Earth Science Enterprise is a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system. JPL is a division of the California Institute of Technology, Pasadena

  10. Deep-sea Hexactinellida (Porifera) of the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Janussen, Dorte; Tabachnick, Konstantin R.; Tendal, Ole S.

    2004-07-01

    New Hexactinellida from the deep Weddel Sea are described. This moderately diverse hexactinellid fauna includes 14 species belonging to 12 genera, of which five species and one subgenus are new to science: Periphragella antarctica n. sp., Holascus pseudostellatus n. sp., Caulophacus (Caulophacus) discohexactinus n. sp., C. ( Caulodiscus) brandti n. sp., C. ( Oxydiscus) weddelli n. sp., and C. ( Oxydiscus) n. subgen. So far, 20 hexactinellid species have been reported from the deep Weddell Sea, 15 are known from the northern part and 10 only from here, while 10 came from the southern area, and five of these only from there. However, this apparent high "endemism" of Antarctic hexactinellid sponges is most likely the result of severe undersampling of the deep-sea fauna. We find no reason to believe that a division between an oceanic and a more continental group of species exists. The current poor database indicates that a substantial part of the deep hexactinellid fauna of the Weddell Sea is shared with other deep-sea regions, but it does not indicate a special biogeographic relationship with any other ocean.

  11. Brief: Offshore North Sea case histories of the environmentally friendly testing vessel, the Crystal Sea

    SciTech Connect

    Tjelta, O.; Ashwell, C.; Hilmarsen, G.; Taylor, R.W.

    1996-04-01

    One problem during offshore well-test operations, stimulations, and routine workovers are discharges into the air and sea while flaring. These procedures are usually performed by mobile drilling rigs with no storage capacity, and thus, hydrocarbons sequestered must be burned off from the rig flare booms. Another major problem has been the inability of the flare to operate at high flow rates. Because the burning process slows the pace of a test, restricting full flow testing, valuable well information is lost. Flaring of hydrocarbons also represents an economic loss. In the case of oil rigs, for example, flaring not only emits CO{sub 2} into the atmosphere but also burns off usable oil. The Crystal Sea well-test vessel was designed to address the problems inherent to flaring and, at the same time, provide cost efficiency by salvaging usable oil during well testing. The success of her initial two jobs on the Statfjord North satellite field in the Norwegian sector of the North Sea confirms that sale of the salvaged oil normally lost during the flaring process could generate sufficient economic return to pay for the vessel. In addition, with its capability to receive products at twice the flow rate of conventional methods, the increased accuracy of the technical information obtained from the well test further enhances its value for improved reservoir management.

  12. Sea Ice Concentration and Extent

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2014-01-01

    Among the most seasonal and most dynamic parameters on the surface of the Earth is sea ice which at any one time covers about 3-6% of the planet. In the Northern Hemisphere, sea ice grows in extent from about 6 x 10(exp 6) sq km to 16 x 10(exp 6) sq km, while in the Southern Hemisphere, it grows from about 3 x 10(exp 6) sq km to about 19 x 10(exp 6) sq km (Comiso, 2010; Gloersen et al., 1992). Sea ice is up to about 2-3 m thick in the Northern Hemisphere and about 1 m thick in the Southern Hemisphere (Wadhams, 2002), and compared to the average ocean depth of about 3 km, it is a relatively thin, fragile sheet that can break due to waves and winds or melt due to upwelling of warm water. Being constantly advected by winds, waves, and currents, sea ice is very dynamic and usually follows the directions of the many gyres in the polar regions. Despite its vast expanse, the sea ice cover was previously left largely unstudied and it was only in recent years that we have understood its true impact and significance as related to the Earths climate, the oceans, and marine life.

  13. Satellite views of the Bohai Sea, Yellow Sea, and East China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Wei; Wang, Menghua

    2012-10-01

    A comprehensive study of water properties for the Bohai Sea (BS), Yellow Sea (YS), and East China Sea (ECS) has been carried out with 8-year observations between 2002 and 2009 from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua platform. Normalized water-leaving radiance spectra (nLw(?)), chlorophyll-a concentration (Chl-a), diffuse attenuation coefficient at the wavelength of 490 nm (Kd(490)), total suspended matter (TSM), and sea surface temperature (SST) are used to quantify and characterize the physical, optical, biological, and biogeochemical properties and their seasonal and interannual variability in the BS, YS, and ECS regions. The BS, YS, and ECS feature highly turbid waters in the coastal regions and river estuaries with high Kd(490) over ?3 m-1 and TSM concentrations reach over ?50 g m-3. The optical, biological, and biogeochemical property features in these three seas show considerable seasonal variability. The dominant empirical orthogonal function (EOF) mode for Kd(490) and TSM variability in the BS, YS, and ECS regions is the seasonal mode, which accounts for about two-thirds of the total variance. Phytoplankton dynamics in open oceans of the BS, YS, and ECS is also found to play an important role in the Kd(490) variation, while its impact on the ocean turbidity (Kd(490)) is much less than that of seasonal winds and sea surface thermodynamics in coastal regions. The first EOF mode in SST for the regions is seasonal and accounts for nearly 90% of the total SST variance. The major mechanisms that drive ocean color property variations in the BS, YS, and ECS are the seasonal winds, ocean stratification, and sea surface thermodynamics due to the seasonal climate change, as well as coastal bathymetry, seasonal phytoplankton blooms, and river discharges.

  14. Global Sea Rise: a Redetermination

    NASA Astrophysics Data System (ADS)

    Douglas, Bruce C.

    It is well established that sea level trends obtained from tide gauge records shorter than about 50-60 years are corrupted by interdecadal sea level variation. However, only a fraction (<25%) of even the long records exhibit globally consistent trends, because of vertical crustal movements. The coherent trends are from tide gauges not at collisional plate boundaries, and not located in or near areas deeply ice-covered during the last glaciation. Douglas (1991), using ICE-3G values for the postglacial (PGR) rebound correction, found 21 usable records (minimum length 60 years, average 76) in 9 oceanographic groups that gave a mean trend for global sea level rise of 1.8 mm/yr ± 0.1 for the period 1880-1980. In that analysis, a significant inconsistency of PGR-corrected U.S. east coast trends was noted, but not resolved. Now, even after eliminating those trends, more (24) long records (minimum 60 years, average 83) are available, including series in the southern hemisphere not previously used. The mean trend of 9 groups made up of the newly-selected records is also 1.8 mm/yr ± 0.1 for global sea level rise over the last 100+ years. A somewhat smaller set of longer records in 8 groups (minimum 70 years, average 91) gives 1.9 mm/yr ± 0.1 for the mean trend. These values are about an order of magnitude larger than the average over the last few millennia. The recent (in historical terms) dramatic increase in the rate of global sea level rise has not been explained, and no acceleration during the last century has been detected. This situation requires additional investigation and confirmation. VLBI/GPS/absolute gravity measurements of crustal motions can be employed to correct many long (60+ years) tide gauge records not now usable because of vertical crustal movements, improving the geographic coverage of sea level trends. Direct altimetric satellite determinations of global sea level rise from satellites such as TOPEX/POSEIDON and its successors can provide an independent estimate in possibly a decade or so, and thereby ascertain whether or not there has been any recent change in the rate of global sea level rise.

  15. Internal and external forcing of sea level variability in the Black Sea

    NASA Astrophysics Data System (ADS)

    Volkov, Denis L.; Landerer, Felix W.

    2015-11-01

    The variability of sea level in the Black Sea is forced by a combination of internal and external processes of atmospheric, oceanic, and terrestrial origin. We use a combination of satellite altimetry and gravity, tide gauge, river discharge, and atmospheric re-analysis data to provide a comprehensive up-to-date analysis of sea level variability in the Black Sea and to quantify the role of different environmental factors that force the variability. The Black Sea is part of a large-scale climatic system that includes the Mediterranean and the North Atlantic. The seasonal sea level budget shows similar contributions of fresh water fluxes (precipitation, evaporation, and river discharge) and the Black Sea outflow, while the impact of the net surface heat flux is smaller although not negligible. We find that the nonseasonal sea level time series in the Black and Aegean seas are significantly correlated, the latter leading by 1 month. This lag is attributed to the adjustment of sea level in the Black Sea to externally forced changes of sea level in the Aegean Sea and to the impact of river discharge. The nonseasonal sea level budget in the Black Sea is dominated by precipitation and evaporation over the sea itself, but external processes such as river discharge and changes in the outflow can also cause some large synoptic-scale sea level anomalies. Sea level is strongly coupled to terrestrial water storage over the Black Sea drainage basin, which is modulated by the North Atlantic Oscillation (NAO). We show that during the low/high NAO southwesterly/northeasterly winds near the Strait of Gibraltar and southerly/northerly winds over the Aegean Sea are able to dynamically increase/decrease sea level in the Mediterranean and Black seas, respectively.

  16. Orientation and open-sea navigation in sea turtles

    PubMed

    Lohmann; Lohmann

    1996-01-01

    Loggerhead sea turtle hatchlings (Caretta caretta L.) emerge from underground nests, scramble to the sea and begin a transoceanic migration by swimming away from their natal beach and into the open ocean. Evidence suggests that hatchlings sequentially use three different sets of cues to maintain orientation during their initial migration offshore. While on the beach, hatchlings find the ocean by crawling towards the lower, brighter seaward horizon and away from the dark, elevated silhouettes of vegetation and dunes. Upon entering the ocean, turtles initially orient seawards by swimming into waves, which can be detected as orbital movements from under water. Laboratory experiments have demonstrated that turtles can transfer a course initiated on the basis of waves or visual cues to a course mediated by a magnetic compass. Thus, by setting a magnetic course on the basis of nearshore cues that indicate the seaward direction, hatchlings may continue on offshore headings after entering deep water beyond sight of land. Sea turtles may use the earth's magnetic field not only as a cue for compass orientation but also as a source of world-wide positional information. Recent experiments have demonstrated that loggerheads can detect subtle differences in magnetic field inclination and intensity, two geomagnetic features that vary across the surface of the earth. Because most nesting beaches and oceanic regions are marked by a unique combination of these features, these findings raise the possibility that adult sea turtles navigate using a bicoordinate magnetic map. PMID:9317364

  17. Future sea-level rise in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Galassi, Gaia; Spada, Giorgio

    2014-05-01

    Secular sea level variations in the Mediterranean Sea are the result of a number of processes characterized by distinct time scales and spatial patterns. Here we predict the future sea level variations in the Mediterranean Sea to year 2050 combining the contributions from terrestrial ice melt (TIM), glacial isostatic adjustment (GIA), and the ocean response (OR) that includes the thermal expansion and the ocean circulation contributions. The three contributions are characterized by comparable magnitudes but distinctly different sea-level fingerprints across the Mediterranean basin. The TIM component of future sea-level rise is taken from Spada et al. (2013) and it is mainly driven by the melt of small glaciers and ice caps and by the dynamic ice loss from Antarctica. The sea-level fingerprint associated with GIA is studied using two distinct models available from the literature: ICE-5G(VM2) (Peltier, 2004) and the ice model progressively developed at the Research School of Earth Sciences (RSES) of the National Australian University (KL05) (see Fleming and Lambeck, 2004 and references therein). Both the GIA and the TIM sea-level predictions have been obtained with the aid of the SELEN program (Spada and Stocchi, 2007). The spatially-averaged OR component, which includes thermosteric and halosteric sea-level variations, recently obtained using a regional coupled ocean-atmosphere model (Carillo et al., 2012), vary between 2 and 7 cm according to scenarios adopted (EA1B and EA1B2, see Meehl at al., 2007). Since the sea-level variations associated with TIM mainly result from the gravitational interactions between the cryosphere components, the oceans and the solid Earth, and long-wavelength rotational variations, they are characterized by a very smooth global pattern and by a marked zonal symmetry reflecting the dipole geometry of the ice sources. Since the Mediterranean Sea is located in the intermediate far-field of major ice sources, TIM sea-level changes have sub-eustatic values (i.e. they do not exceed the global average) and show little (but still significant) variations across the basin associated with the subsidence driven by the meltwater load. For year 2050, TIM calculations predict a sea-level rise of ~10 and ~30 cm for the mid range and the high end scenarios, respectively. Mainly because of the distinct mantle viscosity profiles adopted in ICE-5G(VM2) and KL05, the GIA patterns differ significantly and, in contrast with the TIM fingerprint, are both characterized by strong variations across the Mediterranean Sea, showing maximum values in the bulk of the basin. For the OR component, a significant geographical variation is observed across the Mediterranean sub-basins, corresponding to different Atlantic boundary conditionsAccording to this study, the total future sea-level rise for year 2050 will reach maximum values for the extreme scenario (hig-hend prediction for TIM, KL05 for GIA and EA1B2 for OR) of ˜ 27 cm in average with peak of ˜ 30 cm in the central sub-basins. Our results show that when these three components of future sea-level rise are simultaneously considered, the spatial variability is enhanced because of the neatly distinct geometry of the three fingerprints. References: Carillo, A., Sannino, G., Artale, V., Ruti, P., Calmanti, S., DellAquila, A., 2012, Clim. Dyn. 39 (9-10), 2167-2184; Fleming, K. and Lambeck, K., 2004, Quat. Sci. Rev. 23 (9-10), 1053-1077; Meehl, G.A., and 11 others, 2007, in Climate Change 2007: The Physical Science Basis, Cambridge University Press; Peltier W.R., 2004, Annu. Rev. Earth Pl. Sc., 32, 111-149; Spada, G. and Stocchi, P., 2007, Comput. and Geosci., 33(4), 538-562; Spada G., Bamber J. L., Hurkmans R. T. W. L., 2013, Geophys. Res. Lett., 1-5, 40.

  18. Factors controlling ebro deep-sea fan growth, Mediterranean Sea

    SciTech Connect

    Nelson, C.H.; Maldonado, A.; Alonso, B.; Palanques, A.; Ryan, W.B.F.; Kastens, K.; O'Connel, S.

    1985-01-01

    Tectonic, sediment-source and sea-level factors control depositional patterns of the Ebro deep-sea fan system. In unstable, steep continental slope terrain, mass movement of material results in wide gullied canyons and formation of non-channelized debris aprons. These fan channels develop low sinuosity and generally traverse the continental rise without feeding into depositional lobes because of steep gradients (1:50 to 1:100) and sediment draining into the subsiding Valencia Valley graben. An abundance of sediment input points from mass failure and many river-fed canyons contributes to a depositional pattern of side-by-side debris aprons and separate channel-levee complexes. When a large sediment supply feeds a channel for a relatively long period 1) fan valley sinuosity increases: 2) channel walls are modified through undercutting, slumping, and crevasse splays: 3) channel bifurcation occurs: 4) incipient depositional lobe formation begins. Lowering of sea levels in Late Pleistocene time permitted the access of coarse river sediment to slope valleys and promoted deposition of numerous turbidites and active growth of the fan. During the Holocene, when sea levels have been high, a regime of hemipelagic sedimentation, mass movement, and debris apron sedimentation has dominated.

  19. Sea-Floor Spreading and Transform Faults

    ERIC Educational Resources Information Center

    Armstrong, Ronald E.; And Others

    1978-01-01

    Presents the Crustal Evolution Education Project (CEEP) instructional module on Sea-Floor Spreading and Transform Faults. The module includes activities and materials required, procedures, summary questions, and extension ideas for teaching Sea-Floor Spreading. (SL)

  20. Sea Otter Pup Wants the Worm

    USGS Multimedia Gallery

    A sea otter pup watches eagerly as its mother eats a fat innkeeper worm in Monterey Bay, California. USGS scientists study sea otters in efforts to help the threatened species continue to recover from near extinction....

  1. Antarctic sea ice mapping using the AVHRR

    SciTech Connect

    Zibordi, G. ); Van Woert, M.L. . SeaSpace, Inc.)

    1993-08-01

    A sea ice mapping scheme based on Advanced Very High Resolution Radiometer (AVHRR) data from the National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites has been developed and applied to daylight images taken between November 1989 to January 1990 and November 1990 to January 1991 over the Weddell and the Ross Seas. After masking the continent and ice shelves, sea ice is discriminated from clouds and open sea using thresholds applied to the multidimensional space formed by AVHRR Channel 2, 3, and 4 radiances. Sea ice concentrations in cloud-free regions are then computed using the tie-point method. Results based on the analysis of more than 70 images show that the proposed scheme is capable of properly discriminating between sea ice, open sea, and clouds, under most conditions, thus allowing high resolution sea ice maps to be produced during the austral summer season.

  2. Annual sea level variability of the coastal ocean: The Baltic Sea-North Sea transition zone

    NASA Astrophysics Data System (ADS)

    Passaro, M.; Cipollini, P.; Benveniste, J.

    2015-04-01

    The annual cycle is a major contribution to the nontidal variability in sea level. Its characteristics can vary substantially even at a regional scale, particularly in an area of high variability such as the coastal ocean. This study uses previously validated coastal altimetry solutions (from ALES data set) and the reference ESA Sea Level Climate Change Initiative data set to improve the understanding of the annual cycle during the Envisat years (2002-2010) in the North Sea-Baltic Sea transition area. This area of study is chosen because of the complex coastal morphology and the availability of in situ measurements. To our knowledge, this is the first time that the improvements brought by coastal satellite altimetry to the description of the annual variability of the sea level have been evaluated and discussed. The findings are interpreted with the help of a local climatology and wind stress from a reanalysis model. The coastal amplitude of the annual cycle estimated from ALES altimetry data is in better agreement with estimations derived from in situ data than the one from the reference data set. Wind stress is found to be the main driver of annual cycle variability throughout the domain, while different steric contributions are responsible for the differences within and among the subbasins. We conclude that the ALES coastal altimetry product is a reliable data set to study the annual cycle of the sea level at a regional scale, and the strategy described in this research can be applied to other areas of the coastal ocean where the coverage from the tide gauges is not sufficient.

  3. Sensitivity study of a dynamic thermodynamic sea ice model

    SciTech Connect

    Holland, D.M.; Mysak, L.A.; Manak, D.K. )

    1993-02-15

    A numerical simulation of the seasonal sea ice cover in the Arctic Ocean and the Greenland, Iceland, and Norwegian seas is presented. The sea ice model is extracted from Oberhuber's (1990) coupled sea ice-mixed layer-isopycnal general circulation model and is written in spherical coordinates. The advantage of such a model over previous sea ice models is that it can be easily coupled to either global atmospheric or ocean general circulation models written in spherical coordinates. In this model, the thermodynamics are a modification of that of Parkinson and Washington, while the dynamics use the full Hibler viscous-plastic rheology. Monthly thermodynamic and dynamic forcing fields for the atmosphere and ocean are specified. The simulations of the seasonal cycle of ice thickness, compactness, and velocity, for a control set of parameters, compare favorably with the known seasonal characteristics of these fields. A sensitivity study of the control simulation of the seasonal sea ice cover is presented. The sensitivity runs are carried out under three different themes, namely, numerical conditions, parameter values, and physical processes. This last theme refers to experiments in which physical processes are either newly added or completely removed from the model. Approximately 80 sensitivity runs have been performed in which a change from the control run environment has been implemented. Comparisons have been made between the control run and a particular sensitivity run based on time series of the seasonal cycle of the domain-averaged ice thickness, compactness, areal coverage, and kinetic energy. In addition, spatially varying fields of ice thickness, compactness, velocity, and surface temperature for each season are presented for selected experiments. A brief description and discussion of the more interesting experiments are presented. The simulation of the seasonal cycle of Arctic sea ice cover is shown to be robust. 31 refs., 20 figs., 5 tabs.

  4. Tides of the British Seas

    ERIC Educational Resources Information Center

    Sandon, Frank

    1975-01-01

    Examines the gravitational effects and the way that local conditions interact with these effects to produce the tides characteristic of the British seas. Presents some effects of tides including the possibility of harnessing tidal energy and the effect of tidal friction on the use of the earth as a clock. (GS)

  5. Sea Lamprey, an Invasive Fish

    USGS Multimedia Gallery

    Invasive sea lamprey prey on commercially important fish species such as lake trout, living off of the blood and body fluids of adult fish. It is one of many fish species that USGS scientists study from the USGS Research Vessel Muskie. These lamprey belong to the Great Lakes Fisheries Commissio...

  6. Sea Lamprey, an Invasive Fish

    USGS Multimedia Gallery

    Invasive sea lamprey prey on commercially important fish species such as lake trout, living off of the blood and body fluids of adult fish.  It is one of many fish species that USGS scientists study from the USGS Research Vessel Muskie. These lamprey belong to the Great Lakes Fisheries Com...

  7. Photonic aspect of sea shell

    NASA Astrophysics Data System (ADS)

    Sarkar, Aditi; Gangopadhyay, Arnab; Sarkar, A.

    2013-02-01

    Sea shells are the bio-originating layered tough shelters of mollusks. Optical aspects and the functional nature of it are studied in this work using experimental probes like Fourier transform infra-red spectroscopy (FTIR) and UVVIS spectroscopy. It shows Photonic behavior in IR region of electromagnetic wave. Corresponding photonic band gap is estimated.

  8. Salton Sea Ecosystem Monitoring Project

    USGS Publications Warehouse

    Miles, A. Keith; Ricca, Mark A.; Meckstroth, Anne; Spring, Sarah E.

    2009-01-01

    The Salton Sea is critically important for wintering and breeding waterbirds, but faces an uncertain future due to water delivery reductions imposed by the Interstate and Federal Quantification Settlement Agreement of 2003. The current preferred alternative for wetland restoration at the Salton Sea is saline habitat impoundments created to mitigate the anticipated loss of wetland habitat. In 2006, a 50-hectare experimental complex that consisted of four inter-connected, shallow water saline habitat ponds (SHP) was constructed at the southeastern shoreline of the Salton Sea and flooded with blended waters from the Alamo River and Salton Sea. The present study evaluated ecological risks and benefits of the SHP concept prior to widespread restoration actions. This study was designed to evaluate (1) baseline chemical, nutrient, and contaminant measures from physical and biological constituents, (2) aquatic invertebrate community structure and colonization patterns, and (3) productivity of and contaminant risks to nesting waterbirds at the SHP. These factors were evaluated and compared with those of nearby waterbird habitat, that is, reference sites.

  9. Energy from the sea waves

    SciTech Connect

    Blandino, A.; Brighenti, A.; Vielmo, P.

    1980-01-01

    The main results relevant to certain themes are shown and discussed together with the computerized procedures by which they have been obtained. These themes include the following: (a) Evaluation of the sea wave energy content; (b) Interaction between the incident wave field and the absorbing device; and (c) Economic assessment of the wave power generator.

  10. Westward intensification in marginal seas

    NASA Astrophysics Data System (ADS)

    Chen, Gengxin; Xue, Huijie

    2014-03-01

    An idealized model was used to examine why the strong western boundary current (WBC) is observed in the South China Sea (SCS) but not in the Gulf of Mexico (GOM) and Japan/East Sea (JES). Results suggested that the stronger WBC in the SCS is mainly attributed to the direct contribution of the inflow and the strong monsoon. Although the Gulf Stream transports a large amount of water into the GOM, the passage in the southeast corner guides the inflow out of the gulf and inhibits the inflow from intensifying the WBC. Meanwhile, the wind stress in the GOM is weakest among the three marginal seas. The meridional ocean ridge and the particular layout of the continental slope of JES prevent the whole basin from participating in the westward intensification. Besides, the throughflow has adverse effects on the formulation of WBC in JES. The variation of Coriolis parameter with latitude leads to the westward intensification in marginal seas. However, a strong WBC cannot be observed in the absence of reasonable collocation of wind, inflow, and topography.

  11. A Deep-Sea Simulation.

    ERIC Educational Resources Information Center

    Montes, Georgia E.

    1997-01-01

    Describes an activity that simulates exploration techniques used in deep-sea explorations and teaches students how this technology can be used to take a closer look inside volcanoes, inspect hazardous waste sites such as nuclear reactors, and explore other environments dangerous to humans. (DDR)

  12. The Sea Ice Board Game

    ERIC Educational Resources Information Center

    Bertram, Kathryn Berry

    2008-01-01

    The National Science Foundation-funded Arctic Climate Modeling Program (ACMP) provides "curriculum resource-based professional development" materials that combine current science information with practical classroom instruction embedded with "best practice" techniques for teaching science to diverse students. The Sea Ice Board Game, described…

  13. Sea Ice and Oceanographic Conditions.

    ERIC Educational Resources Information Center

    Oceanus, 1986

    1986-01-01

    The coastal waters of the Beaufort Sea are covered with ice three-fourths of the year. These waters (during winter) are discussed by considering: consolidation of coastal ice; under-ice water; brine circulation; biological energy; life under the ice (including kelp and larger animals); food chains; and ice break-up. (JN)

  14. Ploughing the deep sea floor.

    PubMed

    Puig, Pere; Canals, Miquel; Company, Joan B; Martn, Jacobo; Amblas, David; Lastras, Galderic; Palanques, Albert

    2012-09-13

    Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations and benthic communities has received much attention, but trawling can also modify the physical properties of seafloor sediments, watersediment chemical exchanges and sediment fluxes. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and shelf environments, however, where the capacity of trawling to modify the seafloor morphology coexists with high-energy natural processes driving sediment erosion, transport and deposition. Here we show that on upper continental slopes, the reworking of the deep sea floor by trawling gradually modifies the shape of the submarine landscape over large spatial scales. We found that trawling-induced sediment displacement and removal from fishing grounds causes the morphology of the deep sea floor to become smoother over time, reducing its original complexity as shown by high-resolution seafloor relief maps. Our results suggest that in recent decades, following the industrialization of fishing fleets, bottom trawling has become an important driver of deep seascape evolution. Given the global dimension of this type of fishery, we anticipate that the morphology of the upper continental slope in many parts of the worlds oceans could be altered by intensive bottom trawling, producing comparable effects on the deep sea floor to those generated by agricultural ploughing on land. PMID:22951970

  15. The Sea Ice Board Game

    ERIC Educational Resources Information Center

    Bertram, Kathryn Berry

    2008-01-01

    The National Science Foundation-funded Arctic Climate Modeling Program (ACMP) provides "curriculum resource-based professional development" materials that combine current science information with practical classroom instruction embedded with "best practice" techniques for teaching science to diverse students. The Sea Ice Board Game, described

  16. Sea Turtle Tracks at Nesting Site

    USGS Multimedia Gallery

    A morning photo depicts evidence of a sea turtle nesting the previous night (from the sea, left; return to sea, right). The protective stakes mark a nest from an earlier week as part of a county research program that marks and records every eighth nest....

  17. Sea Grant: Enhancing K-12 Education.

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.

    1998-01-01

    Sea Grant is a major contributor to marine and aquatic education in K-12 classrooms through curriculum development, teacher education, school programs at field sites, and educational research. Describes Sea Grant's efforts in these areas. Specific programs outlined include Operation Pathfinder, Ohio Sea Grant Partnerships for Great Lakes

  18. 34 CFR 300.230 - SEA flexibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true SEA flexibility. 300.230 Section 300.230 Education... DISABILITIES Local Educational Agency Eligibility 300.230 SEA flexibility. (a) Adjustment to State fiscal... SEA, notwithstanding 300.162 through 300.163 (related to State-level nonsupplanting and...

  19. 33 CFR 2.22 - Territorial sea.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms 2.22 Territorial sea. (a) With respect to the United States, the following apply (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  20. 33 CFR 2.22 - Territorial sea.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms 2.22 Territorial sea. (a) With respect to the United States, the following apply (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  1. 33 CFR 2.22 - Territorial sea.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms 2.22 Territorial sea. (a) With respect to the United States, the following apply (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  2. 34 CFR 300.230 - SEA flexibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 2 2013-07-01 2013-07-01 false SEA flexibility. 300.230 Section 300.230 Education... DISABILITIES Local Educational Agency Eligibility 300.230 SEA flexibility. (a) Adjustment to State fiscal... SEA, notwithstanding 300.162 through 300.163 (related to State-level nonsupplanting and...

  3. 34 CFR 300.230 - SEA flexibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false SEA flexibility. 300.230 Section 300.230 Education... DISABILITIES Local Educational Agency Eligibility 300.230 SEA flexibility. (a) Adjustment to State fiscal... SEA, notwithstanding 300.162 through 300.163 (related to State-level nonsupplanting and...

  4. 33 CFR 2.22 - Territorial sea.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms 2.22 Territorial sea. (a) With respect to the United States, the following apply (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  5. 34 CFR 300.230 - SEA flexibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true SEA flexibility. 300.230 Section 300.230 Education... DISABILITIES Local Educational Agency Eligibility 300.230 SEA flexibility. (a) Adjustment to State fiscal... SEA, notwithstanding 300.162 through 300.163 (related to State-level nonsupplanting and...

  6. 33 CFR 2.22 - Territorial sea.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms 2.22 Territorial sea. (a) With respect to the United States, the following apply (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  7. Isotopic composition and origin of the red sea and salton sea geothermal brines.

    PubMed

    Craig, H

    1966-12-23

    Abstract. Deuterium and oxygen-18 measurements show that the Red Sea and Salton Sea brines are the results of a single process, the leaching of sediments by surface water circulating downward to a geothermal reservoir. The Salton Sea brine is derived from local precipitation but the Red Sea brine originates 1000 kilometers south of its basin, on the shallow sill which controls the circulation of the Red Sea. On this sill sea water penetrates a thick evaporite sequence to a depth of 2000 meters, and, driven by its increased density relative to sea water, flows northward to emerge in the brine-filled deeps. PMID:17807292

  8. The Impact of Sea Surface Temperature Front on Stratus-Sea Fog over the Yellow and East China Seas

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Li, M.; Liu, F.

    2013-12-01

    A stratus-sea fog event occurred on 3 June 2011 over the Yellow and East China Seas (as shown in figure) is investigated observationally and numerically. Emphasis is put on the influences of the sea surface temperature front (SSTF) and of the synoptic circulations on the transition of stratus to sea fog. The southerly winds from a synoptic high pressure transport water vapor from the East China Sea to the Yellow Sea, while the subsidence induced by the high contributes to the formation of the temperature inversion on the top of the stratus or stratocumulus that appears mainly over the warm flank of a sea surface temperature front in the East China Sea. Forced by the SSTF, there is a secondary cell within the atmospheric boundary layer (ABL), with a sinking branch on the cold flank and a rising one on the warm flank of the SSTF. This sinking branch, in phase with the synoptic subsidence, forces the stratus or stratocumulus to lower in the elevation getting close to the sea surface as these clouds move northward driven by the southerly winds. The cloud droplets can either reach to the sea surface directly or evaporate into water vapor that may condense again when coming close to the cold sea surface to form fog. In this later case, the stratus and fog may separate. The cooling effect of cold sea surface counteracts the adiabatic heating induced by the subsidence and thus helps the transition of stratus to sea fog in the southern Yellow Sea. By smoothing the SSTF in the numerical experiment, the secondary cell weakens and the sea fog patches shrink obviously over the cold flank of the SSTF though the synoptic subsidence and moist advection still exist. A conceptual model is suggested for the transition of stratus to sea fog in the Yellow and East China Seas, which is helpful for the forecast of sea fog over these areas. The satellite visible image of the stratus-fog event. The fog appears in the Yellow Sea and the stratocumulus in the East China Sea.

  9. Facing up to sea rise.

    PubMed

    Pernetta, J

    1994-01-01

    A milder and less extreme climate, abundance of fish and mollusks, transport and communication, and fertile land at low altitudes have drawn humans to coastal areas and river valleys for centuries. More than 60% of the world's population occupy the 150 km closest to the coast. Millions of tourists come to coastlines and small tropical islands for recreation. About 80% of the global fish supply originates from the 19 km closest to the shore. Fish are the only protein source for the rapidly growing populations in many developing countries. Global climate change is increasing the sea level so much that by 2050, the mean increase will be about 38 cm (24-52 cm). The Intergovernmental Panel on Climate Change (IPCC) notes that the effects of sea level rise will differ from place to place. Direct effects are flooding of low-lying coastal areas and increased erosion rates. An indirect effect includes higher water tables and intrusion of saline water into aquifers, resulting in loss of fresh ground water resources. These effects may make coastal areas less suitable for settlement and agriculture. Coral sand settled on top of coral reefs makes up the unstable, small atoll islands of the Pacific and Indian Oceans. People on these islands depend almost entirely on the sea for their livelihood and on the small amount of fresh water with which they grow root crops and drink. Rising sea levels also threaten low lying countries, e.g., Bangladesh, and densely populated deltas, e.g., the Nile. Changes in the frequency and severity of flooding will increase Bangladesh's dependence on foreign aid. IPCC sees 3 possible responses to the rising sea level: defense, retreat, and accommodation. Accommodation is the only practical choice for many developing countries. A switch from rice cultivation to mariculture of prawns and fish is an example of accommodation. We need to more completely understand the natural processes in coastal environments to be better prepared for climate change. PMID:12287486

  10. Management of the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Wolff, W. J.; Zijlstra, J. J.

    1980-03-01

    The Wadden Sea situated along the North Sea coasts of Denmark, the Federal Republic of Germany and The Netherlands represents one of the world's largest bar-built type of estuaries. The area is a typical sedimentation and mineralization basin, with a large influx of organic matter from the adjoining North Sea, consequently a delicate oxygen balance and a rich benthic macrofauna, poor in species, which serves as food for juveniles of some commercially important North Sea fishes and for large numbers of migrating and wintering waders and waterfowl. Past and present activities of the human society in the area include fisheries (mainly for shrimp and mussels, semi-culture), shipping, land reclamation, recreation, dredging for sand and shells, and waste discharge from industries and human communities. Until the present these activities, although sometimes conflicting, did not fundamentally affect the area and its biota (pollution excluded), but future claims, including the construction of large deep-sea harbours, drilling for natural gas and oil, large-scale land reclamation and increased industrialization etc., might gradually induce degradation. For instance, area reduction by continued land reclamation could lead to irreversible losses of specific biotopes (e. g. salt-marshes, mud-flats), which could affect the size of bird and fish populations in a much wider region. Increased pollution, which has already inflicted damage on bird and seal populations, could reduce the fauna and hence the value of the area as a natural sanctuary. In the event of a proposal for a new human activity in the area, the present standing practice in the countries concerned requires an evaluation of its safety and economic aspects and its environmental impact. However, the various plans are considered separately and there is a general need for integrated management of the area.

  11. Thermal biology of sea snakes and sea kraits.

    PubMed

    Heatwole, Harold; Grech, Alana; Monahan, John F; King, Susan; Marsh, Helene

    2012-08-01

    Temperature probably had no direct effect on the evolution of sea kraits within their center of origin, a geologically stable thermal zone straddling the equator, but may have indirectly affected expansions and contractions in distributions beyond that zone through global fluctuations that caused alternation of higher and lower sea levels. The northern limit of the Laticauda colubrina complex seems to be the 20°C isotherm; in the south, the range does not reach that isotherm because there is no land (also a habitat requirement of sea kraits) within the zone of suitable temperature. The relationship of temperature to the pattern of geographic variation in morphology supports either the hypothesis of peripheral convergence or the developmental hypothesis but does not distinguish between them. Quadratic surfaces relating cumulative scores for coloration and morphological characters to global position showed a strong latitudinal component and an even stronger longitudinal one in which the direction of the latitudinal effect was reversed between east and west. A multivariate analysis revealed that while morphological characters vary significantly by location and climate when tested separately, when the influence of location on morphology is taken into account, no residual relationship between climate and morphology remains. Most marine snakes have mean upper temperature tolerances between 39°C and 40°C and operate at temperatures much nearer their upper thermal limits than their lower limits but still avoid deleterious extremes by diving from excessively hot water to deeper, cooler strata, and by surfacing when water is cold. At the surface in still water in sunlight, Pelamis can maintain its body temperature slightly above that of the water, but whether this is significant in nature is questionable. As temperature falls below 18-20°C, survival time is progressively reduced, accompanied by the successive occurrence of cessation of feeding, cessation of swimming, and failure to orient. Acclimation does not seem to be in this species' repertoire. In the water column, marine snakes track water temperature; on land, sea kraits can thermoregulate by basking, selecting favorable locations, and by kleptothermy. Laticauda colubrina adjusts its reproductive cycle geographically in ways that avoid breeding in the coldest months. Mean voluntary diving time is not temperature-dependent within the normal range of temperatures experienced by marine snakes in the field, but is reduced in water colder than 20°C. On land, much as while diving in the sea, sea kraits maintain long periods of apnea; intervals between breaths are inversely related to temperature. PMID:22669175

  12. Distribution characteristics of marine litter on the sea bed of the East China Sea and the South Sea of Korea

    NASA Astrophysics Data System (ADS)

    Lee, Dae-In; Cho, Hyeon-Seo; Jeong, Sun-Beom

    2006-10-01

    The types, quantities, and distribution of marine litter found on the sea bed of the East China Sea and the South Sea of Korea are surveyed. Surveys were evaluated using bottom trawl nets during 1996-2005 cruises. Mean distribution densities were high in coastal seas, especially in the South Sea of Korea offshore from Yeosu, with 109.8 kg km -2, and low in the East China Sea, with densities of 30.6 kg km -2. Fishing gear, such as pots, nets, octopus jars, and fishing lines, accounted for about 42-72% and 37-62% of litter items in the East China Sea and the South Sea of Korea, respectively, whereas the contributions of rubber, vinyl, metal, plastic, glass, wood, and clothing were below 30% mainly. Rope and drum composition fluctuated greatly, between 54% and 0%. Eel and net pots dominated the marine debris of the South Sea of Korea, and some vinyl, plastics, and fishing gear made in Korea, China, and Japan were collected in abundance in the East China Sea. Fishing gear was probably discarded into the sea, deliberately or inadvertently, by fishing operations. A comprehensive joint approach by Korea, China, and Japan is needed for the continuous monitoring of input sources, the actual conditions, and the behavior of marine litter for protection against litter pollution and fisheries resource management in this area.

  13. Polar low climatology over the Nordic and Barents seas based on satellite passive microwave data

    NASA Astrophysics Data System (ADS)

    Smirnova, Julia E.; Golubkin, Pavel A.; Bobylev, Leonid P.; Zabolotskikh, Elizaveta V.; Chapron, Bertrand

    2015-07-01

    A new climatology of polar lows over the Nordic and Barents seas for 14 seasons (1995/1996-2008/2009) is presented. For the first time in climatological studies of polar lows an approach based on satellite passive microwave data was adopted for polar low identification. A total of 637 polar lows were found in 14 extended winter seasons by combining total atmospheric water vapor content and sea surface wind speed fields retrieved from Special Sensor Microwave/Imager data. As derived, the polar low activity in the Norwegian and Barents Seas is found to be almost equal, and the main polar low genesis area is located northeastward of the North Cape. For the Barents Sea, a significant correlation is found between the number of polar lows and mean sea ice extent. Individual indicative polar low characteristics (i.e., diameter, lifetime, distance traveled, translation speed, and maximum wind speed) are also presented.

  14. Sea Ice Thickness Variability in Fram Strait

    NASA Astrophysics Data System (ADS)

    Gerland, S.; Renner, A.; Haas, C.; Nicolaus, M.; Granskog, M.; Hansen, E.; Hendricks, S.; Hudson, S. R.; Beckers, J.; Goodwin, H.

    2011-12-01

    On this poster, we show results from airborne electromagnetic (EM) sea ice thickness measurements demonstrating the temporal and spatial complexity of the ice thickness distribution in Fram Strait between Greenland and Svalbard. Knowledge about the spatial and temporal sea ice thickness distribution in the Arctic Ocean is necessary to assess the state of the sea-ice cover, and to understand relevant processes and changes. Since 2003, the Norwegian Polar Institute (NPI) has been conducting systematic in situ monitoring of sea ice thickness in the western Fram Strait, using both ground and airborne techniques. Fram Strait is a key region for large-scale ice dynamics in the Arctic. It represents the main export route for sea ice from the Arctic and the only deep strait connecting the interior Arctic Ocean and the rest of the world oceans. The ice thickness distribution in this region is the result of a combination of dynamic and thermodynamic sea ice processes. Transects for airborne EM observations were flown by NPI in spring 2005, 2008, and late summer 2010, and by the Alfred Wegener Institute in spring 2009. The regional ice thickness distributions are supplemented with ground measurements including snow thickness observations taken on ice stations during ship expeditions in spring 2005, 2007, and 2008 and annually in late summer from 2003 to 2011. From all these observations, we can show the differing characteristics of the thickness distributions in spring (2005, 2008, 2009) and late summer (2010) when the ice thickness is at its annual maximum (end of the freezing period) and minimum (end of the melting period), respectively. The ice thickness distribution can also vary spatially over short distances in north-south direction. Features such as the East Greenland Polynya, which varies in size for a given time from year to year, contribute to the spatial and temporal variability on the Greenlandic Shelf. In spring 2005, a gradient is visible across Fram Strait from thinner pack ice at the eastern ice edge towards thicker pack ice on the Greenland shelf in the western part of Fram Strait with thick multiyear ice. The spring modal thickness ranged from about 2 m to 3.5 m. In contrast, the spatial variability of the modal thickness in 2008 is larger than observed in the previous campaigns with a wider range of modal ice thicknesses, predominantly due to thinner ice than in 2005. Finally, during late summer 2010 modal thicknesses in the central and eastern part of Fram Strait ranged from about 1 to 2 m. At the same time distributions were in general narrower than observed in previous years, showing a decrease of the fraction of thick pressure ridges. Thick ice was measured only in the westernmost part of Fram Strait. These observations are in agreement with a reported trend towards a generally larger amount of first-year ice versus multiyear ice in the Arctic.

  15. On the Sea, From the Sea, Of the Sea: The Physics of maritime Governance

    NASA Astrophysics Data System (ADS)

    James, Royce; Page, Eric

    2014-03-01

    The United States Coast Guard Academy Physics Section is proud to present our initial conceptions of ``On the Sea, From the Sea, Of the Sea: The Physics of Maritime Governance,'' a program funded by an APS Outreach Grant in 2013. In our classes, the Physics Section has focused on active student engagement for the past ten years. Recently, we have refined our program to make heavy use of Interactive Lecture Demonstrations (ILDs) and our own highly interactive adaptation which we call Interactive Lecture Labs (ILLs). ``On the Sea'' is a unique opportunity to investigate their use in a different learning modality from our standard college level military academic use. Multigenerational science, technology, engineering, and mathematics (STEM) projects are a prolific source of academic discourse, while learning through play has been touted as an effective learning tool. We plan to investigate group and individual participation, intragroup communication, demographics, and prior skill (or education) in comparison to outcomes in learning objectives through projects designed to educate the Coast Guard Academy and surrounding community on the physics of the Coast Guard's missions. Progress on the lab and demonstration designs, community participation, and our emerging ILL and ILD pedagogical methods, will be reported.

  16. Flavor Structure of Intrinsic Nucleon Sea

    NASA Astrophysics Data System (ADS)

    Peng, Jen-Chieh; Chang, Wen-Chen; Cheng, Hai-Yang; Liu, Keh-Fei

    2015-09-01

    The concept of intrinsic charm suggested by Brodsky et al. is extended to lighter quarks. Extraction of the intrinsic ?, d, and s seas is obtained from an analysis of the d - ?, s + s, and ? + d - s -s distributions. The connection between the intrinsic/extrinsic seas and the connected/disconnected seas in lattice QCD is also examined. It is shown that the connected and disconnected components for the ?(x) + d( x) sea can be separated. The striking x-dependence of the [ s( x) + s( x)]/[ ?(x) + d( x)] ratio is interpreted as an interplay between the connected and disconnected seas.

  17. Sea ice in the Baltic Sea A review

    NASA Astrophysics Data System (ADS)

    Granskog, Mats; Kaartokallio, Hermanni; Kuosa, Harri; Thomas, David N.; Vainio, Jouni

    2006-10-01

    Although the seasonal ice cover of the Baltic Sea has many similarities to its oceanic counterpart in Polar Seas and Oceans, there are many unique characteristics that mainly result from the brackish waters from which the ice is formed, resulting in low bulk salinities and porosities. In addition, due to the milder climate than Polar regions, the annual maximum ice extent is highly variable, and rain and freeze-melt cycles can occur throughout winter. Up to 35% of the sea ice mass can be composed from metamorphic snow, rather than frozen seawater, and in places snow and superimposed ice can make up to 50% of the total ice thickness. There is pronounced atmospheric deposition of inorganic nutrients and heavy metals onto the ice, and in the Bothnian Bay it is estimated that 5% of the total annual flux of nitrogen and phosphorus and 20-40% of lead and cadmium may be deposited onto the ice fields from the atmosphere. It is yet unclear whether or not the ice is simply a passive store for atmospherically deposited compounds, or if they are transformed through photochemical processes or biological accumulation before released at ice and snow melt. As in Polar sea ice, the Baltic ice can harbour rich biological assemblages, both within the ice itself, and on the peripheries of the ice at the ice/water interface. Much progress has been made in recent years to study the composition of these assemblages as well as measuring biogeochemical processes within the ice related to those in underlying waters. The high dissolved organic matter loading of Baltic waters and ice result in the ice having quite different chemical characteristics than those known from Polar Oceans. The high dissolved organic material load is also responsible in large degree to shape the optical properties of Baltic Sea ice, with high absorption of solar radiation at shorter wavelengths, a prerequisite for active photochemistry of dissolved organic matter. Land-fast ice in the Baltic also greatly alters the mixing characteristics of river waters flowing into coastal waters. River plumes extend under the ice to a much greater distance, and with greater stability than in ice-free conditions. Under-ice plumes not only alter the mixing properties of the waters, but also result in changed ice growth dynamics, and ice biological assemblages, with the underside of the ice being encased, in the extreme case, with a frozen freshwater layer. There is a pronounced gradient in ice types from more saline ice in the south to freshwater ice in the north. The former is characteristically more porous and supports more ice-associated biology than the latter. Ice conditions also vary considerably in different parts of the Baltic Sea, with ice persisting for over half a year in the northernmost part of the Baltic Sea, the Bothnian Bay. In the southern Baltic Sea, ice appears only during severe winters.

  18. Alkenone production in the East Sea/Japan Sea

    NASA Astrophysics Data System (ADS)

    Lee, Kyung Eun; Lee, Sunghye; Park, Yonggi; Lee, Ho Jin; Harada, Naomi

    2014-02-01

    To test the applicability of alkenones as a proxy for past sea surface temperature (SST) in the East Sea (Japan Sea), this study investigated the season and depth of alkenone production in the area. Surface and subsurface seawater samples were collected from the East Sea during cruises carried out by the National Fisheries Research and Development Institute of Korea in 2008-2010. Surface samples were filtered for suspended material at two-month intervals. Subsurface samples were collected at water depths of 20, 50, 70 and 100 m by CTD bottle casts at two stations, one a coastal station and the other an offshore station. The results of alkenone analysis show that the concentration of total C37 alkenones was generally high in the surface mixed layer and decreased with depth, indicating that alkenones were most likely produced in or close to the surface mixed layer. Alkenone concentration varied seasonally: high in spring to fall and significantly reduced in winter. Comparisons of alkenone-based temperatures with in situ seawater temperatures show that alkenone temperatures measured from suspended particles in the surface waters were close to in situ SST in summer but were lower in winter. During winter, when alkenone production is significantly reduced, alkenones may be suspended for relatively long times and are likely to be advected from the north by eddies from Subpolar Front meanders. In summer when new production of alkenones increases, the settling velocity of alkenones appears to increase and residence time becomes shorter than in winter, suggesting that particles are less likely to be significantly advected at that time. Importantly, at the offshore station, coretop alkenone temperature corresponds to annual-averaged SST, while at the coastal station it corresponds to summer-to-fall averaged SST.

  19. Intermediate water ventilation in the Nordic seas during MIS 2

    NASA Astrophysics Data System (ADS)

    RRvik, Kari-Lise; Rasmussen, Tine L.; Hald, Morten; Husum, Katrine

    2013-05-01

    A high-resolution marine record from the northern Norwegian continental margin off Lofoten is used to reconstruct changes in the oceanography of the Nordic seas during marine isotope stage (MIS) 2 including the Last Glacial Maximum and early deglaciation circa 25 to 16 ka. The period was characterized by generally warm subsurface water temperatures >2C and inflow of Atlantic surface water. Several events were characterized by decrease in ventilation of the intermediate water and low subsurface temperature and salinity. They correlate with colder atmospheric temperatures as seen in ice cores. The events terminated with gradual strengthening of the intermediate water ventilation and increase in subsurface temperature. The generation of intermediate water was unstable and experienced climate and ventilation changes on millennial and centennial timescales. The changes appear consistent with modeling experiments that predict short-lasting circulation stops during MIS 2 due to release of meltwater in the Nordic seas.

  20. The distribution and diversity of sea cucumbers in the coral reefs of the South China Sea, Sulu Sea and Sulawesi Sea

    NASA Astrophysics Data System (ADS)

    Woo, Sau Pinn; Yasin, Zulfigar; Ismail, Siti Hasmah; Tan, Shau Hwai

    2013-11-01

    A study on the distribution and diversity of sea cucumbers in the coral reefs of the South China Sea, Sulu Sea and Sulawesi Sea was carried out in July 2009. The survey was done using wandering transect underwater with SCUBA. Twelve species of sea cucumber were found from four different families and nine genera. The most dominant family was Holothuriidae (five species), followed by Stichopodidae (three species), Synaptidae (three species) and Cucumariidae with only one species. The most dominant species found around the island was Pearsonothuria graffei, which can be found abundantly on substrate of dead corals in a wide range of depth (6-15 m). The Sulawesi Sea showed a higher diversity of sea cucumber with seven different species compared to the South China Sea with only six different species and Sulu Sea with only two species. Ordination by multidimensional scaling of Bray-Curtis similarities clustered the sampling locations to three main clusters with two outgroups. Previous studies done indicated a higher diversity of sea cucumber as compared to this study. This can be indication that the population and diversity of sea cucumbers in the reef is under threat.

  1. Winter snow cover on sea ice in the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Massom, Robert A.; Drinkwater, Mark R.; Haas, Christian

    1997-01-01

    Measurements of snow thickness, temperature, salinity, density, and stratigraphy acquired during the 1992 Winter Weddell Gyre Study are presented. Results indicate that the winter snow cover on sea ice in the Weddell Sea is extremely variable. Extreme fluctuations in Antarctic synoptic conditions (air temperature, precipitation, humidity, and wind speed) occur during the austral winter. They result in unique modifications and additions to the snow layer during the aging process and act to stabilize an otherwise easily wind-redistributed shallow snow cover and develop well-packed drift features. The latter occur even over relatively undeformed areas of sea ice and have a significant localized effect on the snow thickness distribution. Significant variability in snow grain size (mean 2.733.12 mm) and density (0.320.09 g cm-3) is observed as a result of cyclical switches between high- and low-temperature gradient metamorphism. Multiple icy layers indicate multiple thaw-freeze events. One such event occurred during a 3-day station, during which the air temperature rose by 22C in 12 hours (to approximately 0C). This paper also examines mechanisms for flooding of the snow-ice interface, including snow loading. Even where the latter is not a factor, the layer of snow immediately above the snow-ice interface is commonly damp and saline (>10). Limitations in the data set are discussed, and comparisons are drawn with other experiments.

  2. Climate modulation on sea surface height in China seas

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoshuang; Wang, Xidong; Cao, Yingzhi; Zhang, Lianxin; Shao, Caixia; Sun, Chunjian; Wu, Xinrong; Fu, Hongli; Xuan, Lili

    2015-09-01

    The climate modulation on the sea surface height (SSH) in China seas is investigated using a China Ocean Reanalysis (CORA) dataset from 1958-2008. The dataset is constructed by assimilating the temperature/salinity profiles derived from the satellite altimetry data and historical observational temperature/salinity profiles. Based on the Empirical Orthogonal Function (EOF), the CORA sea surface height anomaly (SSHa) is decomposed, and the interannual and decadal variability of the first three leading modes are analyzed. On the interannual timescale, the first principal component (PC1) is significant positively correlated with the El Niño/Southern Oscillation (ENSO). On the decadal timescale, North Pacific Gyre Oscillation (NPGO) has significant negative correlation with PC1 whereas Pacific Decadal Oscillation (PDO) is in phase with PC3. Analysis shows that the decadal variability of SSH is mainly modulated by the wind stress curl variability related to the NPGO and PDO. In addition, the effect of net heat flux associated to the NPGO and PDO on SSH is also investigated, with net heat flux variability in the Luzon strait and tropic Pacific found to influence the decadal variability of SSH.

  3. Cabled ocean observatories in Sea of Oman and Arabian Sea

    NASA Astrophysics Data System (ADS)

    DiMarco, Steven F.; Wang, Zhankun; Jochens, Ann; Stoessel, Marion; Howard, Matthew K.; Belabbassi, Leila; Ingle, Stephanie; du Vall, Ken

    2012-07-01

    An ocean observatoryconsisting of a real-time, cabled array in the Sea of Oman and an internally recording, autonomous mooring array recently upgraded to a cabled array in the northern Arabian Seacelebrated more than 2500 days of continuous operation in July 2012. The observatory, which measures a range of properties, such as water current velocities, temperature, salinity, pressure, dissolved oxygen, and turbidity, is part of the Lighthouse Ocean Research Initiative (LORI) project [du Vall et al., 2011], which was designed as a pilot project and installed in 2005 in the region off Abu Bakara (Figures 1a and 1b). The initial goal of the project was to prove that an in situ, cabled ocean observatory can return high-quality scientific data on a real-time basis over longer time periods than conventional moored systems. That same year, an autonomous array was deployed off Ras al Hadd and on Murray Ridge in the Arabian Sea (Figure 1a).

  4. Air-Sea heat fluxes over the Iceland Sea

    NASA Astrophysics Data System (ADS)

    Petersen, Gudrun Nina; Harden, Ben E.; Renfrew, Ian A.

    2015-04-01

    On a monthly mean scale the Iceland Sea has been shown to be a region of local heat flux minimum while there are also indications that there may be dense water formation in the region. To investigate if the atmospheric conditions over the Iceland Sea can results in significant high heat flux events on shorter time scales data from a meteorological buoy, that was deployed in the area for about two years, is analysed. The observations are compared to ERA-Interim data, which is shown to generally perform very well for this central Iceland Sea location. Synoptic-scale weather patterns during different heat flux events are then examined. The high flux events with winds from the north are often found to be short lived and in between there are long period of low fluxes. Thus the high flux events are disguised in annual and monthly means. However, it still remains to be seen whether the heat fluxes in the region are large enough to drive the ocean convection needed to produce dense water.

  5. A sea of worms: polychaete checklist of the Adriatic Sea.

    PubMed

    Mikac, Barbara

    2015-01-01

    The checklist of polychaetes of the Adriatic Sea (Mediterranean) based on bibliographic sources published from 1840 to 2014, as well as on novel data, with 49 new records for the area, is herein presented. The Adriatic Sea polychaete fauna comprises at present of 764 species in 360 genera and 62 families. The richest family is the Syllidae, with 112 species (c.a. 15% of the all taxa). Eight families account for as much as 50% of the diversity (Syllidae, Serpulidae, Sabellidae, Phyllodocidae, Spionidae, Polynoidae, Terebellidae and Nereididae). Among the three Adriatic sectors (Northern, Central and Southern Adriatic), the Northern Adriatic is the richest one, whereas the composition of the most diverse families is very similar in all sectors. Data on endemisms (6), aliens (29) and valid species with the type locality in the Adriatic Sea (90) are also discussed. The list of all relevant papers citing each species in the Adriatic is included, allowing future detailed information retrievals for distinct purposes. Results suggest that the number of species will keep increasing in the future, as new surveys will be undertaken, so regular updates of the present list will be necessary. PMID:25947537

  6. Lithosphere-scale 3D gravity modelling of the Barents Sea and Kara Sea

    NASA Astrophysics Data System (ADS)

    Klitzke, P.; Faleide, J.; Sippel, J.; Scheck-Wenderoth, M.

    2013-12-01

    The Barents - Kara Sea region covers the major part of the European Arctic shelf. Its northern and western boundaries are young passive margins which originate from early Paleocene-Eocene opening of the Eurasia Basin and the Norwegian-Greenland Sea. In contrast, the basement of the Barents and Kara shelves has been consolidated much earlier, during three major late Precambrian to Permian orogenies. Additionally, the shelf experienced multiple episodes of localised subsidence which resulted in the formation of ultra-deep sedimentary basins varying strongly in their geometry between different subregions. Consequently, the preserved sedimentary record is interrupted by major megasequence boundaries that are well-described in the western Barents Sea. Using this subdivision for the sedimentary record, we traced four major megasequence boundaries across the Barents and Kara shelves by analysing interpreted seismic refraction and reflection data, geological maps and previously published 3D-models. We integrate this shallow information into a 3D geological model and complement the latter downward with the top crystalline crust, the Moho and a new lithosphere-asthenosphere boundary. The sedimentary units have been assigned physical properties considering the respective lithology to calculate a depth-dependent density distribution. Thereby, the obtained bulk densities also account for late Cenozoic uplift/erosion and the maximum Pleistocene ice sheet thickness. For the lithospheric mantle, the density distribution is constrained by an earlier published velocity model (Levshin et al., 2007). On the base of isostatic calculations and 3D gravity modelling the density configuration of the crystalline crust and the geometry of potential high-density bodies is investigated. Finally, we correlate preserved sediment maxima and reconstructed erosion maps with subsedimentary velocity and density variations to gain new insights into the development of Barents and Kara Sea basins. Levshin, A. L., Schweitzer, J., Weidle, C., Shapiro, N. M., & Ritzwoller, M. H. (2007). Surface wave tomography of the Barents Sea and surrounding regions. Geophysical Journal International, 170(1), 441-459. doi:10.1111/j.1365-246X.2006.03285.x

  7. Micromechanics of Sea Urchin Spines

    PubMed Central

    Tsafnat, Naomi; Fitz Gerald, John D.; Le, Hai N.; Stachurski, Zbigniew H.

    2012-01-01

    The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spines unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spines architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material. PMID:22984468

  8. Water masses and 129I distribution in the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Alfimov, Vasily; Aldahan, Ala; Possnert, Gran

    2013-01-01

    The application of the radioactive isotope iodine-129 as a tracer of water circulation in the oceans has provided interesting information with respect to sources and mixing of different water masses. We here present results of 129I distribution in water profiles located in the Nordic Seas and use the isotope to fingerprint water masses in the region. The samples were collected by the US research vessel Knorr in May-June 2002. 129I signatures along the Norwegian Sea reflect a mixing of 129I-rich surface water along the Scandinavian continental slope and 129I-poor North Atlantic surface water. These two water masses become less segregated along the Fram Strait where apparent 129I enrichment penetrates the return Arctic flow into the East Greenland Current. The 129I data further suggest existence of a water mass that is not entirely labeled with respect to origin at the Denmark Strait bottom water. This water parcel probably originates from the Iceland Sea. 129I data also shed light on the major deep water outflow from the Nordic Seas located at the Faeroe Bank Channel.

  9. Influence of sea level rise on the dynamics of salt inflows in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Hordoir, Robinson; Axell, Lars; Lptien, Ulrike; Dietze, Heiner; Kuznetsov, Ivan

    2015-10-01

    The Baltic Sea is a marginal sea, located in a highly industrialized region in Central Northern Europe. Saltwater inflows from the North Sea and associated ventilation of the deep exert crucial control on the entire Baltic Sea ecosystem. This study explores the impact of anticipated sea level changes on the dynamics of those inflows. We use a numerical oceanic general circulation model covering both the Baltic and the North Sea. The model successfully retraces the essential ventilation dynamics throughout the period 1961-2007. A suite of idealized experiments suggests that rising sea level is associated with intensified ventilation as saltwater inflows become stronger, longer, and more frequent. Expressed quantitatively as a salinity increase in the deep central Baltic Sea, we find that a sea level rise of 1 m triggers a saltening of more than 1 PSU. This substantial increase in ventilation is the consequence of the increasing cross section in the Danish Straits amplified by a reduction of vertical mixing.

  10. Variability and Trends in Sea Ice Extent and Ice Production in the Ross Sea

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino; Kwok, Ronald; Martin, Seelye; Gordon, Arnold L.

    2011-01-01

    Salt release during sea ice formation in the Ross Sea coastal regions is regarded as a primary forcing for the regional generation of Antarctic Bottom Water. Passive microwave data from November 1978 through 2008 are used to examine the detailed seasonal and interannual characteristics of the sea ice cover of the Ross Sea and the adjacent Bellingshausen and Amundsen seas. For this period the sea ice extent in the Ross Sea shows the greatest increase of all the Antarctic seas. Variability in the ice cover in these regions is linked to changes in the Southern Annular Mode and secondarily to the Antarctic Circumpolar Wave. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate of increase in the net ice export of about 30,000 sq km/yr. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 cu km/yr, which is almost identical, within error bars, to our estimate of the trend in ice production. The increase in brine rejection in the Ross Shelf Polynya associated with the estimated increase with the ice production, however, is not consistent with the reported Ross Sea salinity decrease. The locally generated sea ice enhancement of Ross Sea salinity may be offset by an increase of relatively low salinity of the water advected into the region from the Amundsen Sea, a consequence of increased precipitation and regional glacial ice melt.

  11. Dsp in Moroccan Mediterranean Sea.

    NASA Astrophysics Data System (ADS)

    Rachid, Fadel

    At sea temperate, there is usually a sole major floraison of the phytoplancton (in the spring) that exhausts the available stock of nutritious salt. This phenomenon is natural. It's more known under the name of "red tide or colored waters", it brings about a danger, with hazardous consequences on the wildlife water wildlife. The toxins emitted by certain seaweeds, of this phytoplancton, are transmitted through the trophic chain to man. Sometimes the contamination of these sea fruits provokes empoisoning to the consumers. Sometimes phytoplanctonics efflorescences do not present any significant coloring but can generate an increased liberation of toxins in sea water. The relative concentration of the one here then is detected in the shellfishes. These organisms concentrate the phocotoxines in their hepatopancreas. These are therefore bio potential indicators of the sea environment. We studied, in parallel, the variation of the characteristic abiotics of the Mediterranean sites previously choosen (physico-chimicals parameters and oceanographics parameters) and the variation of the relative toxicity of the bio indicators in every site. It in springs that the zones navies, subjected to important water provisions coming from a river, undergo several excessive floraisons during the spring and the summer, thanks to their continuous supplying in nutriments. We noted that the arrival new water masses. We draw from this that the coastal areas, due to the precipitations of the winter, translates itself at the level of the embouchure of the estuary Oued Laou by the maximum concentration of contained toxins in the shellfishes and that these waters were loaded with drifts of the olive waste, liquid loss abandoned to himself after extraction of the oil of the renowned olives of this region.

  12. Primary productivity in the sea

    SciTech Connect

    Falkowski, P.G.

    1980-01-01

    Recent progress in primary productivity is discussed in the book based on 27 symposia texts and 19 poster abstracts. Most papers deal with particular cellular processes in pelagic phytoplankton and their relationship to whole plant photosynthesis and growth. In addition, presentations on the productivity of the seaweed, Laminaria, zooxanthellae and whole corals are included. Other articles discuss predictive modeling, new developments in remote sensing, nutrient regeneration within the sea, grazing effects, and carbon cycling. (JMT)

  13. Salton Sea solar pond project

    NASA Technical Reports Server (NTRS)

    French, R. L.; Meitlis, I.

    1980-01-01

    The feasibility of constructing salt gradient solar ponds within the Salton Sea is being studied. These ponds would serve a dual purpose: (1) become a depository for unwanted salt and (2) supply thermal energy for driving turbine electric power systems. Under present circumstances, the rise in salinity is expected to eliminate fish life and create other unfavorable conditions. The proposed concept would have a power generation potential of 600 MWe.

  14. Danish North Sea crude assayed

    SciTech Connect

    Rhodes, A.K.

    1994-09-12

    Danish North Sea blend was assayed earlier this year. The light, sweet crude comprises crude oil from 10 fields. The crude is piped from offshore production facilities to the A/S Dansk Shell refinery at Fredericia, Denmark. Fig. 1 shows the boiling point curve for the crude, and Fig. 2 illustrates the metals content (vanadium, nickel, and iron), as a function of distillation temperature. The table lists properties of the crude and its fractions.

  15. Fracture of multiyear sea ice

    NASA Astrophysics Data System (ADS)

    Sammonds, P. R.; Murrell, S. A. F.; Rist, M. A.

    1998-09-01

    The fracture and flow of multiyear sea ice was investigated under triaxial compression and uniaxial tension in the temperature range -40 to -3.5C, for strain rates from 10-7 to 10-2s-1 and for confining pressures up to 30 MPa using 40 mm diameter specimens. Specimens both in the horizontal plane of the multiyear floe and perpendicular to this plane were tested. The results of short-rod fracture toughness tests on multiyear and first-year sea ice at temperatures -20C are also reported. The multiyear sea ice came from an unridged portion of a single floe about 7 m thick, which was found to be massive and not blocky with large voids. The ice had low salinity and high porosity. The inelastic deformation of multiyear sea ice was found to be strongly dependent upon strain rate, temperature, and confining pressure. In compression, four main types of deformation were observed. (1) Under uniaxial compression, completely brittle fracture at high strain rates (of 10-3 to 10-2 s-1) was characterized by multiple axial splitting. (2) Application of even a small confining pressure inhibited splitting, and fracture took place by the formation of a narrow shear fault inclined at 453. (3) At higher confining pressures, plastic deformation accompanied substantial cracking activity. (4) However, at still higher confining pressures, cracking was completely inhibited and deformation was entirely plastic. At -20C, shear fracture occurred according to a maximum shear stress criterion and hence was pressure independent, with crack nucleation dominating the fracture behavior. At -40C, however, the shear fracture stress was found to be strongly pressure dependent up to 14 MPa and could be described in terms of a Coulombic failure envelope. The unusual 45 orientation of ice shear fractures, together with the unusual pressure dependencies of ice peak strengths, may be explained by the fact that low-stress slip and cleavage occurs in the basal planes of ice crystals.

  16. Euthanasia across the North Sea

    PubMed Central

    Rigter, Henk; Borst-Eilers, Els; Leenen, H J J

    1988-01-01

    The United Kingdom and The Netherlands are separated by a narrow stretch of sea but in terms of an understanding of euthanasia they seem to be light years apart. An attempt to bridge the information gap seems in order. The position paper on euthanasia published by the Royal Dutch Medical Association contains 16 typed pages.1 In contrast, the report on euthanasia issued by a working party of the British Medical Association is 80 pages in small print.2 PMID:3147088

  17. Medusa Sea Floor Monitoring System

    NASA Technical Reports Server (NTRS)

    Flynn, Michael

    2004-01-01

    The objective of the research described in this poster presentation is to develop technologies to enable fundamental research into understanding the potential for and limits to chemolithoautotrophic life. The Medusa Isosampler (isobaric sampler), for sampling fluids eminating from deep sea hydrothermal vents and cold seep sites analogous to extraterrestrial environments, is described by the presentation. The following instruments are integrated with the isosampler, and also described: in situ flow-through chemical sensor, intrinsic fluorescent-based microbial detector, isotope ratio spectral detector.

  18. Fracture Networks in Sea Ice

    NASA Astrophysics Data System (ADS)

    Vevatne, Jonas; Rimstad, Eivind; Hansen, Alex; Korsnes, Reinert; Hope, Sigmund

    2014-04-01

    Fracturing and refreezing of sea ice in the Kara sea are investigated using complex networkanalysis. By going to the dual network, where the fractures are nodes and their intersectionslinks, we gain access to topological features which are easy to measure and hence comparewith modeled networks. Resulting network reveal statistical properties of the fracturing process.The dual networks have a broad degree distribution, with a scale-free tail, high clusteringand efficiency. The degree-degree correlation profile shows disassortative behavior, indicatingpreferential growth. This implies that long, dominating fractures appear earlier than shorterfractures, and that the short fractures which are created later tend to connect to the longfractures.The knowledge of the fracturing process is used to construct growing fracture network (GFN)model which provides insight into the generation of fracture networks. The GFN model isprimarily based on the observation that fractures in sea ice are likely to end when hitting existingfractures. Based on an investigation of which fractures survive over time, a simple model forrefreezing is also added to the GFN model, and the model is analyzed and compared to the realnetworks.

  19. Respiration in Neonate Sea Turtles

    PubMed Central

    Paladino, Frank V.; Strohl, Kingman P.; Pilar Santidrin, T.; Klann, Kenneth; Spotila, James R.

    2007-01-01

    The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ventilation characteristics that are similar to those of adults: a single breath followed by a long respiratory pause, slow frequency, and high metabolic rate. With hypercapnic challenge, both species responded primarily by elevating respiratory frequency via a decrease in the non-ventilatory period. Leatherback resting tidal volume increased with age but otherwise, neither species resting respiratory pattern nor response to gas challenge changed significantly over the first few days after hatching. At the time of nest emergence, sea turtles have achieved a respiratory pattern that is similar to that of actively diving adults. PMID:17258487

  20. MODIS Global Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Every day the Moderate-resolution Imaging Spectroradiometer (MODIS) measures sea surface temperature over the entire globe with high accuracy. This false-color image shows a one-month composite for May 2001. Red and yellow indicates warmer temperatures, green is an intermediate value, while blues and then purples are progressively colder values. The new MODIS sea surface temperature product will be particularly useful in studies of temperature anomalies, such as El Nino, as well as research into how air-sea interactions drive changes in weather and climate patterns. In the high resolution image, notice the amazing detail in some of the regional current patterns. For instance, notice the cold water currents that move from Antarctica northward along South America's west coast. These cold, deep waters upwell along an equatorial swath around and to the west of the Galapagos Islands. Note the warm, wide currents of the Gulf Stream moving up the United States' east coast, carrying Caribbean warmth toward Newfoundland and across the Atlantic toward Western Europe. Note the warm tongue of water extending from Africa's east coast to well south of the Cape of Good Hope. MODIS was launched in December 1999 aboard NASA's Terra satellite. For more details on this and other MODIS data products, please see NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Ocean Group, NASA GSFC, and the University of Miami

  1. Assessment of 137Cs and 90Sr Fluxes in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Matishov, Gennady; Usiagina, Irina; Kasatkina, Nadezhda; Ilin, Gennadii

    2014-05-01

    On the basis of published and own data the annual balance of radionuclide income/outcome was assessed for 137Cs and 90Sr in the Barents Sea for the period from 1950s to the presnt. The scheme of the isotope balance calculation in the Barents Sea included the following processes:atmospheric fallout; river run-off; liquid radioactive wastes releases, income from the Norwegian and the White Seas; outflow to the adjacent areas through the Novaya Zemlya straits and the transects Svalbard-Franz Josef Land and Franz Josef Land-Novaya Zemlya; radioactive decay. According to the multiyear dynamics, the inflow of 137Cs and 90Sr to the Barents Sea was significantly preconditioned by currents from the Norwegian Sea. Three peaks of 137Cs and 90Sr isotope concentrations were registered for the surface waters on the western border of the Barents Sea. The first one was observed in the mid-1960s and was conditioned by testing of nuclear weapons. The increase of isotope concentrations in 1975 and 1980 was preconditioned by the discharge of atomic waste by the Sellafield nuclear reprocessing plant. Nowadays, after the sewage disposal plant was built, the annual discharge of nuclear waste from Sellafield plant is low. The Norwegian Sea was a major source of 137Cs and 90Sr isotope income into the Barents Sea for the period of 1960-2014. Currently, the transborder transfer of 90Sr and 137Cs from the Norwegian Sea into the Barents Sea constitutes about 99% of income for each element. Atmospheric precipitation had a major impact in the 1950-1960s after the testing of the nuclear weapons, and in 1986 after the accident at Chernobyl Nuclear Power Station. In 1963, the atmospheric precipitation of 137Cs reached 1050 TBq; and that of 90Sr, 630 TBq. In 1986, a significant amount of 137Cs inflow (up to 1010 TBq/year) was registered. The 137Cs isotope income exceeded the 90Sr income in the 1960s-1980s, and equal amounts penetrated into the Barents Sea from the Norwegian Sea in the 1990s. Before the 1990s, 137Cs inflow exceeded outflow in the annual balance, but the opposite pattern is observed nowadays. This tendency of prevailing of 137Cs outflow processes in the Barents Sea may be explained by natural decay and ecosystem self-cleaning of the radioactivity, which has penetrated previously. According to our assumptions, in total, 37400 TBq of 137Cs penetrated, and 26300 TBq of 137Cs were output from the Barents Sea during the period 1950-2010, i.e., 70.2% of this isotope was removed. From the 1960s through the present, the inflow of 90Sr exceeded the outflow. In total, 24800 TBq of 90Sr penetrated, and 19600 TBq of 90Sr were output through the northern and northeastern margins of the Barents Sea, i.e., 79.1% of this isotope was removed. From 1960 through the 1980s, the income/outcome ratio in the Barents Sea was quite stable and constituted 1.4-1.5 for 137Cs and 1.1-1.2 for 90Sr. The increase of the impact of atmospheric precipitation on 137Cs income was up to 42% in 1986 due to the Chernobyl disaster, and the income/outcome ratio increased to 2.6. The atmospheric income of 90Sr in 1986 was minor, and the ratio stayed the same for this isotope.

  2. Sea ice data for all: NSIDC's Arctic Sea Ice News & Analysis

    NASA Astrophysics Data System (ADS)

    Vizcarra, N.; Stroeve, J. C.; Serreze, M. C.; Scambos, T. A.; Meier, W.

    2014-12-01

    Arctic sea ice has long been recognized as a sensitive climate indicator and has undergone a dramatic decline over the past thirty years. The National Snow and Ice Data Center's Arctic Sea Ice News & Analysis blog continues to offer the public a transparent view of sea ice data and analysis. We have expanded our interactive sea ice graph to include Antarctic sea ice in response to increased attention from the public as a result of unexpected behavior of sea ice in the south. This poster explores the blog's new features and how other researchers, the media, and the public are currently using them.

  3. Biogeochemistry in Sea Ice: CICE model developments

    SciTech Connect

    Jeffery, Nicole; Hunke, Elizabeth; Elliott, Scott; Turner, Adrian

    2012-06-18

    Polar primary production unfolds in a dynamic sea ice environment, and the interactions of sea ice with ocean support and mediate this production. In spring, for example, fresh melt water contributes to the shoaling of the mixed layer enhancing ice edge blooms. In contrast, sea ice formation in the fall reduces light penetration to the upper ocean slowing primary production in marine waters. Polar biogeochemical modeling studies typically consider these types of ice-ocean interactions. However, sea ice itself is a biogeochemically active medium, contributing a significant and, possibly, essential source of primary production to polar regions in early spring and fall. Here we present numerical simulations using the Los Alamos Sea Ice Model (CICE) with prognostic salinity and sea ice biogeochemistry. This study investigates the relationship between sea ice multiphase physics and sea ice productivity. Of particular emphasis are the processes of gravity drainage, melt water flushing, and snow loading. During sea ice formation, desalination by gravity drainage facilitates nutrient exchange between ocean and ice maintaining ice algal blooms in early spring. Melt water flushing releases ice algae and nutrients to underlying waters limiting ice production. Finally, snow loading, particularly in the Southern Ocean, forces sea ice below the ocean surface driving an upward flow of nutrient rich water into the ice to the benefit of interior and freeboard communities. Incorporating ice microphysics in CICE has given us an important tool for assessing the importance of these processes for polar algal production at global scales.

  4. Sources of Sea Salts to Coastal Antarctica

    NASA Astrophysics Data System (ADS)

    Curran, M. A.; van Ommen, T. D.; Moy, A. D.; Vance, T.; Wong, G. J.; Goodwin, I. D.; Domensino, B.

    2010-12-01

    Coastal Antarctic sea salt aerosols are partitioned into two main sources, namely ocean sea spray and surface sea ice. The sea spray source is related to windiness over the surface ocean and the action of bubbles bursting. The sea ice source is due to frost flowers which form on the surface of sea ice, which are concentrated in sea salts and are lofted by wind action over the sea ice zone. At high accumulation coastal sites, with seasonal resolution, it is possible to estimate the sources of both using deviations of the sodium to sulphate ratio from that found in seawater. To date, from ice core records in east Antarctica (including iceberg B09B near the Mertz Glacier, Law Dome, Wilkes Land and Wilhelm II land), we have found that the source strength from surface sea ice to the Antarctic ice sheet diminishes with elevation and distance inland. We present new data from coastal ice core sites including Mill Island off the coast of east Antarctica and the upper and lower Totten glacier to the east of Law Dome. Using this combined dataset we estimate the source strengths of sea salt aerosols, their partitioning and quantify the relationship with elevation and distance inland.

  5. Important Norwegian crude assays updated

    SciTech Connect

    Corbett, R.A

    1990-03-12

    New assays on two important Norwegian North Sea crude oils, Statfjord and Gullfaks, are presented. Both are high-quality, low-sulfur crudes that will yield a full range of good-quality products. All assay data came from industry-standard test procedures. The Statfjord field is the largest in the North Sea. Production started in 1979. Statfjord is a typical North Sea crude, produced from three separate platforms and three separate loading buoys with interconnecting lines. Current production is about 700,000 b/d. Gullfaks is produced from a large field in Block 34/10 of the Norwegian sector of the North Sea production area. Gullfaks crude oil is more biodegraded than other crudes from the region. Biodegradation has removed most of the waxy normal paraffins, resulting in a heavier, more naphthenic and aromatic crude.

  6. [Distribution and air-sea fluxes of methane in the Yellow Sea and the East China Sea in the spring].

    PubMed

    Cao, Xing-Peng; Zhang, Gui-Ling; Ma, Xiao; Zhang, Guo-Ling; Liu, Su-Mei

    2013-07-01

    A survey was carried out in the Yellow Sea and the East China Sea from March 17 to April 06 of 2011. Dissolved CH4 in various depths were measured and sea-to-air fluxes were estimated. Methane concentrations in surface and bottom waters ranged between 2.39-29.67 nmol x L(-1) and 2.63-30.63 nmol x L(-1), respectively. Methane concentrations in bottom waters were slightly higher than those in surface waters, suggesting the existence of methane source in bottom waters or sediments. The horizontal distribution of dissolved CH4 showed a decrease from the river mouth to the open sea, and was influenced by the freshwater discharge and the Kuroshio intrusion. Surface methane saturations ranged from 93%-1 038%. Sea to air CH4 fluxes were (2.85 +/- 5.11) micromol x (m2 x d)(-1) (5.18 +/- 9.99) micromol x (m2 x d)(-1) respectively, calculated using the Liss and Merlivat (LM86), the Wanninkhof (W92) relationships and in situ wind speeds, and estimated emission rates of methane from the East China Sea and the Yellow Sea range from 7.05 x 10(-2) - 12.0 x 10(-2) Tg x a(-1) and 1.17 x 10(-2) - 2.20 x 10(-2) Tg x a(-1), respectively. The Yellow Sea and East China Sea are the net sources of atmospheric methane in the spring. PMID:24027984

  7. Early Pliocene Nordic Seas Palaeoceanography - Relation with Ocean Gateways

    NASA Astrophysics Data System (ADS)

    De Schepper, S.; Schreck, M.; Beck, K. M.; Mangerud, G.; Matthiessen, J. J.; Risebrobakken, B.

    2014-12-01

    In the northern high latitude oceans, organic-walled phytoplankton is often the only microfossil group present in the sediment record that can be used for palaeoceanographic and palaeoenvironmental studies. Recently collected dinoflagellate cyst and acritarch records from the Norwegian and Iceland Seas reveal a wide-scale, major assemblage turnover including extinction of several taxa, disappearance of heterotrophic species and decrease in productivity around 4.5 Ma. These changes can most likely be attributed to a reorganization of the ocean circulation and can be interpreted as the establishment of a more modern-like Norwegian Atlantic Current and proto-East Greenland Current. The timing at around 4.5 Ma corresponds favorably to the shoaling of the Central American Seaway and northward flow of Pacific water via the Bering Strait into the North Atlantic, the latter being evidenced by the first arrival of Pacific molluscs in the Iceland (Tjrnes section). The changes in ocean circulation are not restricted to the Nordic Seas, with increased sediment accumulation at several North Atlantic drifts (e.g. Gloria and Eirik drifts) also illustrating important changes in the North Atlantic deep-water circulation.

  8. Microplastic pollution in deep-sea sediments.

    PubMed

    Van Cauwenberghe, Lisbeth; Vanreusel, Ann; Mees, Jan; Janssen, Colin R

    2013-11-01

    Microplastics are small plastic particles (<1 mm) originating from the degradation of larger plastic debris. These microplastics have been accumulating in the marine environment for decades and have been detected throughout the water column and in sublittoral and beach sediments worldwide. However, up to now, it has never been established whether microplastic presence in sediments is limited to accumulation hot spots such as the continental shelf, or whether they are also present in deep-sea sediments. Here we show, for the first time ever, that microplastics have indeed reached the most remote of marine environments: the deep sea. We found plastic particles sized in the micrometre range in deep-sea sediments collected at four locations representing different deep-sea habitats ranging in depth from 1100 to 5000 m. Our results demonstrate that microplastic pollution has spread throughout the world's seas and oceans, into the remote and largely unknown deep sea. PMID:24035457

  9. Sea ice, climate, and multiscale composites

    NASA Astrophysics Data System (ADS)

    Golden, Kenneth

    2014-03-01

    In September of 2012, the area of the Arctic Ocean covered by sea ice reached its lowest level ever recorded in more than three decades of satellite measurements. In fact, compared to the 1980's and 1990's, this represents a loss of more than half of the summer Arctic sea ice pack. While global climate models generally predict sea ice declines over the 21st century, the precipitous losses observed so far have significantly outpaced most projections. I will discuss how mathematical models of composite materials and statistical physics are being used to study key sea ice processes and advance how sea ice is represented in climate models. This work is helping to improve projections of the fate of Earth's ice packs, and the response of polar ecosystems. A brief video of a recent Antarctic expedition where sea ice properties were measured will be shown. Supported by NSF and ONR.

  10. Sea level anomalies exacerbate beach erosion

    NASA Astrophysics Data System (ADS)

    Theuerkauf, Ethan J.; Rodriguez, Antonio B.; Fegley, Stephen R.; Luettich, Richard A.

    2014-07-01

    Sea level anomalies are intra-seasonal increases in water level forced by meteorological and oceanographic processes unrelated to storms. The effects of sea level anomalies on beach morphology are unknown but important to constrain because these events have been recognized over large stretches of continental margins. Here, we present beach erosion measurements along Onslow Beach, a barrier island on the U.S. East Coast, in response to a year with frequent sea level anomalies and no major storms. The anomalies enabled extensive erosion, which was similar and in most places greater than the erosion that occurred during a year with a hurricane. These results highlight the importance of sea level anomalies in facilitating coastal erosion and advocate for their inclusion in beach-erosion models and management plans. Sea level anomalies amplify the erosive effects of accelerated sea level rise and changes in storminess associated with global climate change.

  11. Physic of the nucleon sea quark distributions

    NASA Astrophysics Data System (ADS)

    Vogt, R.

    Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However, recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that overlineu < overlined in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

  12. Skillful prediction of Barents Sea ice cover

    NASA Astrophysics Data System (ADS)

    Onarheim, Ingrid H.; Eldevik, Tor; rthun, Marius; Ingvaldsen, Randi B.; Smedsrud, Lars H.

    2015-07-01

    A main concern of present climate change is the Arctic sea ice cover. In wintertime, its observed variability is largely carried by the Barents Sea. Here we propose and evaluate a simple quantitative and prognostic framework based on first principles and rooted in observations to predict the annual mean Barents Sea ice cover, which variance is carried by the winter ice (96%). By using observed ocean heat transport and sea ice area, the proposed framework appears skillful and explains 50% of the observed sea ice variance up to 2 years in advance. The qualitative prediction of increase versus decrease in ice cover is correct 88% of the time. Model imperfections can largely be diagnosed from simultaneous meridional winds. The framework and skill are supported by a 60 year simulation from a regional ice-ocean model. We particularly predict that the winter sea ice cover for 2016 will be slightly less than 2015.

  13. The Dead Sea transform fault system

    NASA Astrophysics Data System (ADS)

    Girdler, R. W.

    1990-08-01

    A new map showing the major features of the Dead Sea transform fault system based on seismicity, satellite imagery, geological maps and bathymetric charts is presented. Special attention is given to the possible northward continuation of the transform system beneath the Mediterranean Sea near Ed Damur, south of Beirut. The map shows the Dead Sea transform system to be a series of offset, overlapping, left-lateral transform faults with a rhombochasm between each pair. The system has similarities with the equatorial fracture zones in the Atlantic Ocean. Throughout, the Dead Sea transform system is considered in its regional setting, i.e. as extending from the Red Sea spreading centre in the south to the Eurasian collision zone in the north. It is suggested that it may intersect the latter somewhere east of Cyprus making that area the northernmost termination of the Dead Sea transform system.

  14. Physics of the nucleon sea quark distributions

    SciTech Connect

    Vogt, R.

    2000-03-10

    Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However,recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that (bar u) < (bar d) in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

  15. Sea otter health: challenging a pet hypothesis

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  16. Sea otter health: Challenging a pet hypothesis

    PubMed Central

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  17. The International Arctic Seas Assessment Project

    SciTech Connect

    Linsley, G.S.; Sjoeblom, K.L.

    1994-07-01

    The International Arctic Seas Assessment Project (IASAP) was initiated in 1993 to address widespread concern over the possible health and environmental impacts associated with the radioactive waste dumped into the shallow waters of the Arctic Seas. This article discusses the project with these general topics: A brief history of dumping activities; the international control system; perspectives on arctic Seas dumping; the IASAP aims and implementation; the IASAP work plan and progress. 2 figs.

  18. Sea Surface Salinity : Research Challenges and Opportunities

    NASA Technical Reports Server (NTRS)

    Halpern, David; Lagerloef, Gary; Font, Jordi

    2012-01-01

    Sea surface salinity (SSS) can be important in regulating sea surface temperature (SST). Two technological breakthrough satellite SSS missions, Aquarius and Soil Moisture and Ocean Salinity (SMOS), are currently producing high-quality SSS data. This paper provides an overview of the importance of SSS for weather and climate applications and describes the Aquarius and SMOS missions. The newness of adequately sampled SSS data prompted a first-time at-sea field campaign devoted to improved understanding of SSS variations.

  19. Sea otter health: Challenging a pet hypothesis.

    PubMed

    Lafferty, Kevin D

    2015-12-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  20. Lena River Delta and East Siberian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  1. Scientific reticence and sea level rise

    NASA Astrophysics Data System (ADS)

    Hansen, J. E.

    2007-04-01

    I suggest that a 'scientific reticence' is inhibiting the communication of a threat of a potentially large sea level rise. Delay is dangerous because of system inertias that could create a situation with future sea level changes out of our control. I argue for calling together a panel of scientific leaders to hear evidence and issue a prompt plain-written report on current understanding of the sea level change issue.

  2. SeaWiFS: Summer in Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Ross Sea has been somewhat cloud free lately, providing SeaWiFS with views such as this one from December 26, 2001. Note the deep green water; this is a highly productive part of the world'd oceans. Also note the ice gathered around McMurdo Sound. The ice is making it difficult for penguins to reach their food supply. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  3. Uncertainty estimation for operational ocean forecast productsa multi-model ensemble for the North Sea and the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Golbeck, Inga; Li, Xin; Janssen, Frank; Brning, Thorger; Nielsen, Jacob W.; Huess, Vibeke; Sderkvist, Johan; Bchmann, Bjarne; Siiri, Simo-Matti; Vh-Piikki, Olga; Hackett, Bruce; Kristensen, Nils M.; Engedahl, Harald; Blockley, Ed; Sellar, Alistair; Lagemaa, Priidik; Ozer, Jose; Legrand, Sebastien; Ljungemyr, Patrik; Axell, Lars

    2015-12-01

    Multi-model ensembles for sea surface temperature (SST), sea surface salinity (SSS), sea surface currents (SSC), and water transports have been developed for the North Sea and the Baltic Sea using outputs from several operational ocean forecasting models provided by different institutes. The individual models differ in model code, resolution, boundary conditions, atmospheric forcing, and data assimilation. The ensembles are produced on a daily basis. Daily statistics are calculated for each parameter giving information about the spread of the forecasts with standard deviation, ensemble mean and median, and coefficient of variation. High forecast uncertainty, i.e., for SSS and SSC, was found in the Skagerrak, Kattegat (Transition Area between North Sea and Baltic Sea), and the Norwegian Channel. Based on the data collected, longer-term statistical analyses have been done, such as a comparison with satellite data for SST and evaluation of the deviation between forecasts in temporal and spatial scale. Regions of high forecast uncertainty for SSS and SSC have been detected in the Transition Area and the Norwegian Channel where a large spread between the models might evolve due to differences in simulating the frontal structures and their movements. A distinct seasonal pattern could be distinguished for SST with high uncertainty between the forecasts during summer. Forecasts with relatively high deviation from the multi-model ensemble (MME) products or the other individual forecasts were detected for each region and each parameter. The comparison with satellite data showed that the error of the MME products is lowest compared to those of the ensemble members.

  4. Uncertainty estimation for operational ocean forecast productsa multi-model ensemble for the North Sea and the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Golbeck, Inga; Li, Xin; Janssen, Frank; Brning, Thorger; Nielsen, Jacob W.; Huess, Vibeke; Sderkvist, Johan; Bchmann, Bjarne; Siiri, Simo-Matti; Vh-Piikki, Olga; Hackett, Bruce; Kristensen, Nils M.; Engedahl, Harald; Blockley, Ed; Sellar, Alistair; Lagemaa, Priidik; Ozer, Jose; Legrand, Sebastien; Ljungemyr, Patrik; Axell, Lars

    2015-10-01

    Multi-model ensembles for sea surface temperature (SST), sea surface salinity (SSS), sea surface currents (SSC), and water transports have been developed for the North Sea and the Baltic Sea using outputs from several operational ocean forecasting models provided by different institutes. The individual models differ in model code, resolution, boundary conditions, atmospheric forcing, and data assimilation. The ensembles are produced on a daily basis. Daily statistics are calculated for each parameter giving information about the spread of the forecasts with standard deviation, ensemble mean and median, and coefficient of variation. High forecast uncertainty, i.e., for SSS and SSC, was found in the Skagerrak, Kattegat (Transition Area between North Sea and Baltic Sea), and the Norwegian Channel. Based on the data collected, longer-term statistical analyses have been done, such as a comparison with satellite data for SST and evaluation of the deviation between forecasts in temporal and spatial scale. Regions of high forecast uncertainty for SSS and SSC have been detected in the Transition Area and the Norwegian Channel where a large spread between the models might evolve due to differences in simulating the frontal structures and their movements. A distinct seasonal pattern could be distinguished for SST with high uncertainty between the forecasts during summer. Forecasts with relatively high deviation from the multi-model ensemble (MME) products or the other individual forecasts were detected for each region and each parameter. The comparison with satellite data showed that the error of the MME products is lowest compared to those of the ensemble members.

  5. Parasites in the Wadden Sea food web

    NASA Astrophysics Data System (ADS)

    Thieltges, David W.; Engelsma, Marc Y.; Wendling, Carolin C.; Wegner, K. Mathias

    2013-09-01

    While the free-living fauna of the Wadden Sea has received much interest, little is known on the distribution and effects of parasites in the Wadden Sea food web. However, recent studies on this special type of trophic interaction indicate a high diversity of parasites in the Wadden Sea and suggest a multitude of effects on the hosts. This also includes effects on specific predator-prey relationships and the general structure of the food web. Focussing on molluscs, a major group in the Wadden Sea in terms of biomass and abundance and an important link between primary producers and predators, we review existing studies and exemplify the ecological role of parasites in the Wadden Sea food web. First, we give a brief inventory of parasites occurring in the Wadden Sea, ranging from microparasites (e.g. protozoa, bacteria) to macroparasites (e.g. helminths, parasitic copepods) and discuss the effects of spatial scale on heterogeneities in infection levels. We then demonstrate how parasites can affect host population dynamics by acting as a strong mortality factor, causing mollusc mass mortalities. In addition, we will exemplify how parasites can mediate the interaction strength of predator-prey relationships and affect the topological structure of the Wadden Sea food web as a whole. Finally, we highlight some ongoing changes regarding parasitism in the Wadden Sea in the course of global change (e.g. species introduction, climate change) and identify important future research questions to entangle the role of parasites in the Wadden Sea food web.

  6. Sea Ice Entrainment and Sediment Sources

    NASA Astrophysics Data System (ADS)

    Miles, S.; Darby, D. A.; Jakobsson, M.; Rigor, I.

    2007-12-01

    More than 20 sea ice sediment samples collected during the Healy-Oden Trans-Arctic Expedition (HOTRAX-'05) and the Lomonosov Ridge off Greenland Expedition (LOMROG-'07) along with 18 dirty ice samples from previous expeditions back to the early 1970's show a consistent trend of several sources especially the Laptev and Kara Seas and northern Canada. Modern sea ice back-trajectories from the coordinates of the dirty sea ice samples using past drifts of this ice from the International Buoy Drift Program indicate a close match to the Fe grain sources. Comparison with several sediment cores from across the Arctic and in Fram Strait indicate that Holocene sediment that is primarily transported by sea ice contains the same sources based on Fe oxide grain chemical fingerprint matches with circum-Arctic source areas previously characterized. Observations of encounters with dirty ice by HOTRAX and LOMROG icebreaker expeditions indicate that while a small percentage of sea ice contains sediment, this dirty ice is concentrated in bands extending several kilometers and consisting of irregularly spaced patches of dirty ice that are usually less than a 100 meters in width. Also, sea ice containing coarse sediment and/or large shells due to anchor ice are less than 10 percent of dirty sea ice but that they may contain much higher concentrations of sediment than sea ice containing finer sediment from suspension freezing.

  7. Sea level rise and its coastal impacts

    NASA Astrophysics Data System (ADS)

    Cazenave, Anny; Cozannet, Gonéri Le

    2014-02-01

    Global warming in response to accumulation of human-induced greenhouse gases inside the atmosphere has already caused several visible consequences, among them increase of the Earth's mean temperature and ocean heat content, melting of glaciers, and loss of ice from the Greenland and Antarctica ice sheets. Ocean warming and land ice melt in turn are causing sea level to rise. Sea level rise and its impacts on coastal zones have become a question of growing interest in the scientific community, as well as in the media and public. In this review paper, we summarize the most up-to-date knowledge about sea level rise and its causes, highlighting the regional variability that superimposes the global mean rise. We also present sea level projections for the 21st century under different warming scenarios. We next address the issue of the sea level rise impacts. We question whether there is already observational evidence of coastal impacts of sea level rise and highlight the fact that results differ from one location to another. This suggests that the response of coastal systems to sea level rise is highly dependent on local natural and human settings. We finally show that in spite of remaining uncertainties about future sea levels and related impacts, it becomes possible to provide preliminary assessment of regional impacts of sea level rise.

  8. Dynamic Singularity Spectrum Distribution of Sea Clutter

    NASA Astrophysics Data System (ADS)

    Xiong, Gang; Yu, Wenxian; Zhang, Shuning

    2015-12-01

    The fractal and multifractal theory have provided new approaches for radar signal processing and target-detecting under the background of ocean. However, the related research mainly focuses on fractal dimension or multifractal spectrum (MFS) of sea clutter. In this paper, a new dynamic singularity analysis method of sea clutter using MFS distribution is developed, based on moving detrending analysis (DMA-MFSD). Theoretically, we introduce the time information by using cyclic auto-correlation of sea clutter. For transient correlation series, the instantaneous singularity spectrum based on multifractal detrending moving analysis (MF-DMA) algorithm is calculated, and the dynamic singularity spectrum distribution of sea clutter is acquired. In addition, we analyze the time-varying singularity exponent ranges and maximum position function in DMA-MFSD of sea clutter. For the real sea clutter data, we analyze the dynamic singularity spectrum distribution of real sea clutter in level III sea state, and conclude that the radar sea clutter has the non-stationary and time-varying scale characteristic and represents the time-varying singularity spectrum distribution based on the proposed DMA-MFSD method. The DMA-MFSD will also provide reference for nonlinear dynamics and multifractal signal processing.

  9. Biogeochemistry of the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Amrhein, C.; Reese, B. K.; Anderson, M. A.

    2006-12-01

    The Salton Sea is a saline, closed basin lake 70 meters below MSL in the southern desert of California. It is the largest lake in California with a surface area of 945 km2 and an annual inflow of 1,600 million m3. The Sea is hypereutrophic due to nutrient inputs from farm runoff, and anaerobic conditions in the bottom water result in summer and fall releases of hydrogen sulfide and fish kills. The salinity of the Sea is 47 g/L and rising, with an annual salt load of 4 million metric tons. Plans are being developed for construction of a salt repository to control salinization, improve water quality, and maintain the Sea as a refuge for migratory waterfowl. We estimate 700,000 metric tons of calcite are precipitating in the Sea each year, along with 7,000 tons of iron sulfide minerals. Potentially, 70,000 metric tons of hydrogen sulfide are produced in the Sea each year. Measurements of hydrogen sulfide production, reoxidation in the water column, and atmospheric releases will be reported. Hydrodynamic modeling of the current Sea, and the proposed smaller Sea, indicate that partitioning the Sea could lead to persistent stratification and episodic releases of hydrogen sulfide during fall mixing.

  10. Sonmicat: Sea Level Observation System of Catalonia

    NASA Astrophysics Data System (ADS)

    Martinez-Benjamin, J. J.; Termens, A.; Ruiz, A.; Gonzalez Lopez, S.

    2014-12-01

    SONMICAT is the integrated sea level observation system of Catalonia. SONMICAT aims at providing high-quality continous measurements of sea- and land levels at the Catalan coast from tide gauges (relative sea levels) and from modern geodetic techniques (vertical land motion and absolute sea levels) for studies on long-term sea level trends, but also the calibration of satellite altimeters, for instance. This synergy is indeed the only way to get a clear and unambigous picture of what is actually going on at the coast of Catalonia. SONMICAT aims to be: - an integrated sea level monitoring system (different types of data, sources, time and space scales), - a sea level information system handling the data measured by different observation networks, - a local/regional component of international sea level observing systems (GLOSS, ESEAS, etc.), and - a local/regional interface for related European and Global projects and databases (PSML, TIGA, etc.) There is a gap of sea level data (GLOSS, PSML, TIGA) in the coast of Catalonia, although several groups and institutions have started to do some work. SONMICAT will fill it. Up to now, the system has started at l'Estartit and Barcelona harbours. A description of the actual SONMICAT infraestructure and campaigns - especially at Barcelona harbour - are presented. In June 2014, an airborne LiDAR campaign has been carrying on in Barcelona following two ICESat tracks. First results of the airborne survey will also be presented.

  11. Population status of California sea otters

    SciTech Connect

    Not Available

    1988-11-30

    The main objective of the study was to develop a simulation model to facilitate analysis of the risk of oil spills to the threatened California sea otter population. Existing data on the dynamics and demography of the population were synthesized. The additional data needed for model development were collected through radiotelemetry studies of sea otters in Alaska and California. The simulation model contains four interrelated stochastic submodels: a short-term population model, a long-term population model, a sea otter distribution model, and a sea otter movement model. The report includes a detailed description of the model, the data on which it is based, and an operating manual.

  12. Context awareness and sensitivity in SEA implementation

    SciTech Connect

    Hilding-Rydevik, Tuija Bjarnadottir, Holmfridur

    2007-10-15

    The Impact Assessment research community repeatedly asserts that the implementation of Strategic Environmental Assessment (SEA) should take the issue of context into consideration. The primary aim of this paper then is to attempt to give substance to the concept of 'context' in relation to the implementation of SEA. The second aim is to discuss the relevance of context consciousness and sensitivity in relation to one of the main aims given to SEA implementation i.e. to contribute to the 'integration' of environmental perspectives in planning processes. Context must be defined in relation to a certain question. In this paper the question in focus is the assumption that SEA implementation will contribute to integration of environmental issues in planning processes. Research results relating to the use of environmental tools, like for example SEA, and experiences of integration efforts, strongly indicate that the use of a single tool like SEA is not enough to achieve this integration. The current 'context free' normative and procedural assumptions concerning the aim of SEA implementation and 'best practice' in term of SEA can be criticised on the same grounds as normative and procedural planning theories, as being context free. The assumptions behind the current formulations of the aim and best practice of SEA need to be revisited. A firm empirical and theoretical knowledge and discussion is needed, especially in relation to the issue of context and integration. This paper provides a starting point in this direction.

  13. Diseases in North Sea fishes

    NASA Astrophysics Data System (ADS)

    Dethlefsen, V.

    1984-03-01

    Prior to the studies reviewed here, only lymphocystis and skeletal deformities of a variety of fish species and certain diseases of eel were known to occur in the German Bight (North Sea). From 1977 until now, 9 externally visible lesions on North Sea fishes were observed; in addition to those mentioned before, they comprise: fin rot, ulcerations, epidermal papilloma, hyperplasia, pseudobranchial tumour, eye diseases and gill swellings. With the exception of information on changes in frequencies of vertebral deformities of herring from the 1950's to the 1970's, there are no long-term data characterizing changes in frequencies of the diseases under study. For pseudobranchial tumours of cod and epidermal papilloma of dab, information is provided on occurrence and abundance. The distribution pattern of cod afflicted with pseudobranchial tumours is strongly influenced by the migratory behaviour of the fish. Epidermal papillomas of dab were more frequently found at stations within the inner German Bight than in neighbouring areas. The Bight is used for dumping of wastes from titaniumdioxide production. Further disease hot spots are areas off the Humber estuary and the British coast. Analysis of chromium in dab from the German Bight revealed elevated concentrations in epidermal tissues of specimens from the dumping area compared with that found in dab from neighbouring localities. Particulate iron was demonstrated to occur in mucous cells of dab from the dumping area. From increased levels of heavy metals with cancerogenic potential in sensitive target tissues and from increased prevalences of diseased fish in the dumping area it is concluded that these phenomena are possibly causally linked. In the vicinity of the Humber estuary high disease rates were encountered and areas with high prevalences of dab afflicted with epidermal papilloma extended over regions shown to be transport routes for persistent pollutants such as radioactive materials. It is therefore suggested that the long-range distribution of fish diseases in the southern North Sea might reflect the long-range transport of persistent pollutants.

  14. Marine environments in the China Seas and their prediction

    SciTech Connect

    Bao, C.

    1993-12-31

    The China Seas surround the China continent to its south and east, and connect with the Pacific Ocean. In this paper, marine environmental elements in the China Seas such as marine climate, storm surge, sea wave, sea temperature, sea ice, tsunami and red tide, are analyzed. The predication of marine environments, especially oceanic disasters with good accuracy are also given in this paper.

  15. Introduction to the petroleum geology of the North Sea

    SciTech Connect

    Glennie, K.W.

    1984-01-01

    This book presents papers on North Sea oil and gas deposits. Topics considered include North Sea exploration from 1964-1983, the structural framework and the pre-Permian history of the North Sea area, the late Permian period, the Triassic period, the Jurasic period, the Cretaceous period, the Cenozoic era, source rocks of the North Sea, and North Sea hydrocarbon plays.

  16. 50 CFR 648.59 - Sea Scallop Access Areas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Sea Scallop Access Areas. 648.59 Section... Atlantic Sea Scallop Fishery § 648.59 Sea Scallop Access Areas. (a) Delmarva Sea Scallop Access Area. (1... in or from the area known as the Delmarva Sea Scallop Access Area, described in paragraph (a)(2)...

  17. The role of sea ice dynamics in global climate change

    NASA Technical Reports Server (NTRS)

    Hibler, William D., III

    1992-01-01

    The topics covered include the following: general characteristics of sea ice drift; sea ice rheology; ice thickness distribution; sea ice thermodynamic models; equilibrium thermodynamic models; effect of internal brine pockets and snow cover; model simulations of Arctic Sea ice; and sensitivity of sea ice models to climate change.

  18. Aral Sea, Kazakhstan,CIS

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Situated in the middle of an immense desert, much like the Great Salt Lake of Utah, the Aral Sea (45.0N, 59.0E) is landlocked in the center of a broad basin. Rivers flow in but not out; water escapes only by evaporation. In recent years, river water has been diverted for agricultural irrigation and the lake level has fallen 40 to 50 ft., its surface has shrunk by almost 40 % and the salinity has almost tripled. Twenty species of fish are now extinct.

  19. Advanced deep sea diving equipment

    NASA Technical Reports Server (NTRS)

    Danesi, W. A.

    1972-01-01

    Design requirements are generated for a deep sea heavy duty diving system to equip salvage divers with equipment and tools that permit work of the same quality and in times approaching that done on the surface. The system consists of a helmet, a recirculator for removing carbon dioxide, and the diver's dress. The diver controls the inlet flow by the recirculatory control valve and is able to change closed cycle operation to open cycle if malfunction occurs. Proper function of the scrubber in the recirculator minimizes temperature and humidity effects as it filters the returning air.

  20. Unlocking a Sea Ice Secret

    SciTech Connect

    Dr. Rachel Obbard

    2013-04-22

    Dr. Rachel Obbard and her research group from Dartmouth College traveled to the Antarctic to collect samples of sea ice. Next stop: the GeoSoilEnviroCARS x-ray beamline at the Advanced Photon Source at Argonne National Laboratory in Illinois. This U.S. Department of Energy Office of Science synchrotron x-ray research facility gave the Obbard team the frontier scientific tools they needed to study the path bromide takes as it travels from the ocean to the atmosphere.

  1. Submarine glacigenic debris flows, deep-sea channels and past ice-stream behaviour of the East Greenland continental margin

    NASA Astrophysics Data System (ADS)

    Wilken, Manon; Mienert, Juergen

    2006-04-01

    Former glacigenic debris flow (GDF) and deep-sea channel build-up is shown from side-scan sonar, seismic and sediment core data of the passive continental margin of the Greenland Sea. The well-developed deep-sea channel systems cross GDF systems and point towards sediment-laden meltwater production. There is no indication for large-scale submarine sliding such as observed on several locations on the Norwegian margin, where deep-sea channels are far less frequent or do not exist whereas seabed erosion, GDF stacking and trough mouth fans dominate. The observed pattern on the East Greenland margin reflects a contrast to the Norwegian margin in paleo ice-stream extent, dynamics and type of sediment delivery. A conceptual model for ice-sheet behaviour on the continental margin of the Greenland Sea has been developed based on the characteristics, distribution and morphology of GDFs and deep-sea channels in four periods at ca 2.5 Ma, 1.5 Ma, 0.2 Ma and 25 ka. We argue that the erosional capabilities of ice streams on the NE Greenland margin indicated by aggradation versus progradation were less then those of the fast flowing ice streams of the Norwegian margin, and that the ice streams in cross-shelf troughs remained probably distal from the shelf break during the Late Weichselian.

  2. On the flow of Atlantic water and temperature anomalies in the Nordic Seas toward the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Chafik, L.; Nilsson, J.; Skagseth, Å.; Lundberg, P.

    2015-12-01

    The climatic conditions over the Arctic Ocean are strongly influenced by the inflow of warm Atlantic water conveyed by the Norwegian Atlantic Slope Current (NwASC). Based on sea surface height (SSH) data from altimetry, we develop a simple dynamical measure of the NwASC transport to diagnose its spatio-temporal variability. This supports a dynamical division of the NwASC into two flow regimes; the Svinøy Branch (SvB) in the southern Norwegian Sea, and the Fram Strait Branch (FSB) west of Spitsbergen. The SvB transport is well correlated with the SSH and atmospheric variability within the Nordic Seas, factors that also affect the inflow to the Barents Sea. In contrast, the FSB is influenced by regional atmospheric conditions around Svalbard and northern Barents Sea. Using a composite analysis, we further relate anomalous strong SvB flow events to temperature fluctuations along the core of Atlantic water. A warm composite anomaly is found to propagate northward, with a tendency to amplify enroute, after these events. A roughly 12 months delayed temperature signal is identified in the FSB. However, also in the Lofoten Basin interior a delayed temperature signal is found, which appears to originate from the NwASC. This study suggests that hydrographic anomalies both upstream from the North Atlantic, and locally generated in the Norwegian Sea, are important for the oceanic heat and salt transport that eventually enters into the Arctic.

  3. 50 CFR 648.11 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Register citations affecting § 648.11, see the List of CFR Sections Affected, which appears in the Finding... Atlantic deep-sea red crab; or a moratorium permit for summer flounder; to carry a NMFS-certified fisheries... Atlantic deep-sea red crab permit, a skate permit, or a tilefish permit, if requested by the sea...

  4. 50 CFR 648.11 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and... Atlantic deep-sea red crab; or a moratorium permit for summer flounder; to carry a NMFS-certified fisheries... Atlantic deep-sea red crab permit, a skate permit, or a tilefish permit, if requested by the sea...

  5. 50 CFR 648.11 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... Editorial Note: For Federal Register citations affecting § 648.11, see the List of CFR Sections Affected... Atlantic deep-sea red crab; or a moratorium permit for summer flounder; to carry a NMFS-certified fisheries... Atlantic deep-sea red crab permit, a skate permit, or a tilefish permit, if requested by the sea...

  6. 50 CFR 648.11 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Register citations affecting § 648.11, see the List of CFR Sections Affected, which appears in the Finding... Atlantic deep-sea red crab; or a moratorium permit for summer flounder; to carry a NMFS-certified fisheries... Atlantic deep-sea red crab permit, a skate permit, or a tilefish permit, if requested by the sea...

  7. Sea Sources. Bibliographic and Resource Material of Children's Literature of the Sea.

    ERIC Educational Resources Information Center

    Bagnall, Norma

    Writers have often used the sea as background or as a theme in writing for children since it is a natural setting for adventure or exploration and has an attractiveness for all of us. Included in this bibliography is a representative listing of books related to the seas and inland waters, individual stories and poems which have a bearing on sea

  8. Influence of Sea Level Rise on the Dynamics of Salt Inflows in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Hordoir, Robinson; Axell, Lars; Lptien, Ulrike; Dietze, Heiner; Kuznetsov, Ivan

    2015-04-01

    The Baltic Sea is a marginal sea, located in a highly industrialized region in Central Northern Europe. Based on a numerical ocean model covering both the Baltic Sea and North Sea, we explore the impact of anticipated future sea level changes on the dynamics of salt water inflows which transport salty water masses from the North Sea into the Baltic Sea. This deep water renewal is an essential ventilation mechanism that determines the oxygenation of the Baltic Sea. We illustrate in a hindcast simulation for the period 1961-2007 that the ocean model is capable of producing recent ventilation dynamics. Further we explore the effect of sea level changes with an additional suite of hindcast simulations, which differ by prescribed mean sea level increases between 0.5 and 1.5m. We find that with rising sea level, salt water inflows intensify, become longer and more frequent. Expressed in terms of a salinity increase in the deep central Baltic our simulations suggest a sensitivity of more than 1PSU for a sea level increase of 1.5m. This substantial increase in ventilation is predominantly a consequence of the increasing cross-section in the Danish Straits. In addition there is an amplifying contribution that can be explained by a reduced vertical mixing.

  9. Bayesian Hierarchical Air-Sea Interaction Modeling: Application to the Labrador Sea

    NASA Technical Reports Server (NTRS)

    Niiler, Pearn P.

    2002-01-01

    The objectives are to: 1) Organize data from 26 MINIMET drifters in the Labrador Sea, including sensor calibration and error checking of ARGOS transmissions. 2) Produce wind direction, barometer, and sea surface temperature time series. In addition, provide data from historical file of 150 SHARP drifters in the Labrador Sea. 3) Work with data interpretation and data-modeling assimilation issues.

  10. Sea lice as a density-dependent constraint to salmonid farming

    PubMed Central

    Jansen, Peder A.; Kristoffersen, Anja B.; Viljugrein, Hildegunn; Jimenez, Daniel; Aldrin, Magne; Stien, Audun

    2012-01-01

    Fisheries catches worldwide have shown no increase over the last two decades, while aquaculture has been booming. To cover the demand for fish in the growing human population, continued high growth rates in aquaculture are needed. A potential constraint to such growth is infectious diseases, as disease transmission rates are expected to increase with increasing densities of farmed fish. Using an extensive dataset from all farms growing salmonids along the Norwegian coast, we document that densities of farmed salmonids surrounding individual farms have a strong effect on farm levels of parasitic sea lice and efforts to control sea lice infections. Furthermore, increased intervention efforts have been unsuccessful in controlling elevated infection levels in high salmonid density areas in 2009–2010. Our results emphasize host density effects of farmed salmonids on the population dynamics of sea lice and suggest that parasitic sea lice represent a potent negative feedback mechanism that may limit sustainable spatial densities of farmed salmonids. PMID:22319130

  11. Amundsen Sea ice production and transport

    NASA Astrophysics Data System (ADS)

    Assmann, Karen M.; Hellmer, Hartmut H.; Jacobs, Stanley S.

    2005-12-01

    Drift and variability of sea ice in the Amundsen Sea are investigated with ice buoys deployed in March 2000 and a coupled ice-ocean model. The Bremerhaven Regional Ice Ocean Simulations (BRIOS) model results are compared with in situ ocean, atmosphere, and sea ice measurements; satellite observations; and 8-19 months of buoy drift data. We identify a zone of coastal westward drift and a band of faster eastward drift, separated by a broad transition region characterized by variable ice motions. The model represents drift events at scales approaching its resolution but is limited at smaller scales and by deficiencies in the National Centers for Environmental Prediction forcing. Two thirds of the modeled ice production in the southern Amundsen moves westward near the coast, its transport modulated by meridional wind strength, damping sea ice formation in the eastern Ross Sea. Half of the ice exported from the Ross moves eastward into the northern Amundsen Sea, a net sea ice sink that also receives more than one third of the ice generated to its south. A low rate of exchange occurs with the Bellingshausen Sea, which must have a more independent ice regime. Snow ice formation resulting from high precipitation accounts for one quarter of the ice volume in the Amundsen Sea, aiding the formation of thick ice in a region with generally divergent ice drift. Freshwater extraction by sea ice formation is roughly balanced by precipitation and ice shelf melting, but a positive trend in the surface flux is consistent with an Amundsen source for reported freshening in the Ross Sea.

  12. The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

    NASA Astrophysics Data System (ADS)

    Hunt, George L.; Blanchard, Arny L.; Boveng, Peter; Dalpadado, Padmini; Drinkwater, Kenneth F.; Eisner, Lisa; Hopcroft, Russ R.; Kovacs, Kit M.; Norcross, Brenda L.; Renaud, Paul; Reigstad, Marit; Renner, Martin; Skjoldal, Hein Rune; Whitehouse, Andy; Woodgate, Rebecca A.

    2013-01-01

    This paper compares and contrasts the ecosystems of the Barents and Chukchi Seas. Despite their similarity in a number of features, the Barents Sea supports a vast biomass of commercially important fish, but the Chukchi does not. Here we examine a number of aspects of these two seas to ascertain how they are similar and how they differ. We then indentify processes and mechanisms that may be responsible for their similarities and differences. Both the Barents and Chukchi Seas are high latitude, seasonally ice covered, Arctic shelf-seas. Both have strongly advective regimes, and receive water from the south. Water entering the Barents comes from the deep, ice-free and "warm" Norwegian Sea, and contains not only heat, but also a rich supply of zooplankton that supports larval fish in spring. In contrast, Bering Sea water entering the Chukchi in spring and early summer is cold. In spring, this Bering Sea water is depleted of large, lipid-rich zooplankton, thus likely resulting in a relatively low availability of zooplankton for fish. Although primary production on average is similar in the two seas, fish biomass density is an order of magnitude greater in the Barents than in the Chukchi Sea. The Barents Sea supports immense fisheries, whereas the Chukchi Sea does not. The density of cetaceans in the Barents Sea is about double that in the Chukchi Sea, as is the density of nesting seabirds, whereas, the density of pinnipeds in the Chukchi is about double that in the Barents Sea. In the Chukchi Sea, export of carbon to the benthos and benthic biomass may be greater. We hypothesize that the difference in fish abundance in the two seas is driven by differences in the heat and plankton advected into them, and the amount of primary production consumed in the upper water column. However, we suggest that the critical difference between the Chukchi and Barents Seas is the pre-cooled water entering the Chukchi Sea from the south. This cold water, and the winter mixing of the Chukchi Sea as it becomes ice covered, result in water temperatures below the physiological limits of the commercially valuable fish that thrive in the southeastern Bering Sea. If climate change warms the Barents Sea, thereby increasing the open water area via reducing ice cover, productivity at most trophic levels is likely to increase. In the Chukchi, warming should also reduce sea ice cover, permitting a longer production season. However, the shallow northern Bering and Chukchi Seas are expected to continue to be ice-covered in winter, so water there will continue to be cold in winter and spring, and is likely to continue to be a barrier to the movement of temperate fish into the Chukchi Sea. Thus, it is unlikely that large populations of boreal fish species will become established in this Arctic marginal sea.

  13. Processes driving sea ice variability in the Bering Sea in an eddying ocean/sea ice model: Mean seasonal cycle

    NASA Astrophysics Data System (ADS)

    Li, Linghan; McClean, Julie L.; Miller, Arthur J.; Eisenman, Ian; Hendershott, Myrl C.; Papadopoulos, Caroline A.

    2014-12-01

    The seasonal cycle of sea ice variability in the Bering Sea, together with the thermodynamic and dynamic processes that control it, are examined in a fine resolution (1/10°) global coupled ocean/sea-ice model configured in the Community Earth System Model (CESM) framework. The ocean/sea-ice model consists of the Los Alamos National Laboratory Parallel Ocean Program (POP) and the Los Alamos Sea Ice Model (CICE). The model was forced with time-varying reanalysis atmospheric forcing for the time period 1970-1989. This study focuses on the time period 1980-1989. The simulated seasonal-mean fields of sea ice concentration strongly resemble satellite-derived observations, as quantified by root-mean-square errors and pattern correlation coefficients. The sea ice energy budget reveals that the seasonal thermodynamic ice volume changes are dominated by the surface energy flux between the atmosphere and the ice in the northern region and by heat flux from the ocean to the ice along the southern ice edge, especially on the western side. The sea ice force balance analysis shows that sea ice motion is largely associated with wind stress. The force due to divergence of the internal ice stress tensor is large near the land boundaries in the north, and it is small in the central and southern ice-covered region. During winter, which dominates the annual mean, it is found that the simulated sea ice was mainly formed in the northern Bering Sea, with the maximum ice growth rate occurring along the coast due to cold air from northerly winds and ice motion away from the coast. South of St Lawrence Island, winds drive the model sea ice southwestward from the north to the southwestern part of the ice-covered region. Along the ice edge in the western Bering Sea, model sea ice is melted by warm ocean water, which is carried by the simulated Bering Slope Current flowing to the northwest, resulting in the S-shaped asymmetric ice edge. In spring and fall, similar thermodynamic and dynamic patterns occur in the model, but with typically smaller magnitudes and with season-specific geographical and directional differences.

  14. Adriatic Sea Seasonal Circulation Variability

    NASA Astrophysics Data System (ADS)

    Arango, H. G.; Chiggiato, J.

    2003-04-01

    The general circulation of the Adriatic Sea is studied using the Regional Ocean Modeling System (ROMS) with climatological forcing. The seasonal variability in the Adriatic Sea is established and affected by atmospheric forcing, river runoff, and exchanges with the Eastern Mediterranean thermohaline circulation. In addition, the circulation is affected by the complex bathymetry in the basin. Several simulations are carried out to study the sensitivities to grid resolution, climatological atmospheric forcing, vertical mixing parameterization, and interaction with the Eastern Mediterranean. Two horizontal grids are used in this study. The first grid is a variable resolution, curvilinear grid identical to the work of Zavatarelli et al. (2002). The second grid is a uniform, 3-km resolution grid. Three atmospheric forcing datasets with different spatial resolution are used: COADS (1x1), ECMWF operational analyses (0.5x0.5) relative to the period 1998-2001, and LAMBO (0.125x0.125) operational forecast for the same period. Due to the strong atmospheric and buoyancy forcing, the simulations are affected by the choice of vertical mixing parameterization. Three different vertical mixing closure schemes are used in this study including the Mellor-Yamada 2.5, K-profile parameterization (Large et al, 1994), and generic length scale (Umlauf and Burchard, 2001). Comparisons with previous simulations (Zavatarelli et al., 2002) and available data will be discussed.

  15. OCULUS Sea Track Fusion Service

    NASA Astrophysics Data System (ADS)

    Panagiotou, Stylianos C.; Rizogiannis, Constantinos; Katsoulis, Stavros; Lampropoulos, Vassilis; Kanellopoulos, Sotirios; Thomopoulos, Stelios C. A.

    2015-06-01

    Oculus Sea is a complete solution regarding maritime surveillance and communications at Local as well as Central Command and Control level. It includes a robust and independent track fusion service whose main functions include: 1) Interaction with the User to suggest the fusion of two or more tracks, confirm Track ID and Vessel Metadata creation for the fused track, and suggest de-association of two tracks 2) Fusion of same vessel tracks arriving simultaneously from multiple radar sensors featuring track Association, track Fusion of associated tracks to produce a more accurate track, and Multiple tracking filters and fusion algorithms 3) Unique Track ID Generator for each fused track 4) Track Dissemination Service. Oculus Sea Track Fusion Service adopts a system architecture where each sensor is associated with a Kalman estimator/tracker that obtains an estimate of the state vector and its respective error covariance matrix. Finally, at the fusion center, association and track state estimation fusion are carried out. The expected benefits of this system include multi-sensor information fusion, enhanced spatial resolution, and improved target detection.

  16. Salton Sea Scientific Drilling Program

    SciTech Connect

    Sass, J.H.

    1988-01-01

    The Salton Sea Scientific Drilling Program (SSSDP) was the first large-scale drilling project undertaken by the U.S. Continental Scientific Drilling Program. The objectives of the SSSDP were (1) to drill a deep well into the Salton Sea Geothermal Field in the Imperial Valley of California, (2) to retrieve a high percentage of core and cuttings along the entire depth of the well, (3) to obtain a comprehensive suite of geophysical logs, (4) to conduct flow tests at two depths (and to take fluid samples therefrom), and (5) to carry out several downhole experiments. These activities enabled the U.S. Geological Survey and cooperating agencies to study the physical and chemical processes involved in an active hydrothermal system driven by a molten-rock heat source. The SSSDP exceeded its target depth of 10,000 feet, and a comprehensive set of cuttings, cores, and downhole logs was obtained. Two flow tests at different depths were successfully completed. Hydrologic connection between the different producing horizons, however, made the data from the deeper test difficult to interpret. Temperature logging by the Geological Survey and Sandia National Laboratories to establish the equilibrium profile continued until August of 1987. The SSSDP provides a model for scientific cooperation among government agencies, universities, and private industry.

  17. A Climatological study of sea breezes in the Red Sea region of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Khan, Basit A.; Abualnaja, Yasser

    2015-04-01

    Long term near surface observations from 20 stations, buoys, high resolution model data from European Centre for Medium-Range Weather Forecasts (ECMWF) and Weather Research and Forecasting Modeling System (WRF(ARW)) are used to investigate the climatology of sea breezes over the Eastern side of the Red Sea region. Additionally, satellite data from second-generation Meteosat (MSG) and Radar soundings have also been analyzed to investigate major characteristics of sea breeze flow. Sea breezes blow under anticyclonic synoptic conditions, weak gradient winds, intense radiation, relatively cloud-free skies and strong near surface sea - land thermal gradient. In order to identify sea breeze signal a set of criteria based on synoptic condition, diurnal reversal of wind direction and thermal gradient has been devised. Results show that sea breezes in this region occur almost all year, but this meso-scale phenomenon is most frequent in summer months (May to August) when it occurs for almost half of the summer days. The onset of the sea breeze in this region is about 0800 LST (Local Standard Time). The sea breeze decays after 1700 LST, however, the timing of the onset and decay could be affected by season, sea-land thermal gradient, topography, sea-land orientation and the direction and strength of the prevailing wind. The depth of the predicted inflow layer reaches 1 kilometer while the height of sea breeze head may reach 3 kilometers. The rocky mountain range of Al-Sarawat, east of the Red Sea coast, restricts the inland propagation of sea breeze and significantly affects the structure of the flow. A detailed process analysis of the available data is being conducted to better understand the Sea Breeze and its effect on the local meteorology.

  18. Sea ice concentration temporal variability over the Weddell Sea and its relationship with tropical sea surface temperature

    USGS Publications Warehouse

    Barreira, S.; Compagnucci, R.

    2007-01-01

    Principal Components Analysis (PCA) in S-Mode (correlation between temporal series) was performed on sea ice monthly anomalies, in order to investigate which are the main temporal patterns, where are the homogenous areas located and how are they related to the sea surface temperature (SST). This analysis provides 9 patterns (4 in the Amundsen and Bellingshausen Seas and 5 in the Weddell Sea) that represent the most important temporal features that dominated sea ice concentration anomalies (SICA) variability in the Weddell, Amundsen and Bellingshausen Seas over the 1979-2000 period. Monthly Polar Gridded Sea Ice Concentrations data set derived from satellite information generated by NASA Team algorithm and acquired from the National Snow and Ice Data Center (NSIDC) were used. Monthly means SST are provided by the National Center for Environmental Prediction reanalysis. The first temporal pattern series obtained by PCA has its homogeneous area located at the external region of the Weddell and Bellingshausen Seas and Drake Passage, mostly north of 60°S. The second region is centered in 30°W and located at the southeast of the Weddell. The third area is localized east of 30°W and north of 60°S. South of the first area, the fourth PC series has its homogenous region, between 30° and 60°W. The last area is centered at 0° W and south of 60°S. Correlation charts between the five Principal Components series and SST were performed. Positive correlations over the Tropical Pacific Ocean were found for the five PCs when SST series preceded SICA PC series. The sign of the correlation could relate the occurrence of an El Niño/Southern Oscillation (ENSO) warm (cold) event with posterior positive (negative) anomalies of sea ice concentration over the Weddell Sea.

  19. Melting Ice, Rising Seas - Duration: 4 minutes, 32 seconds.

    NASA Video Gallery

    Sea level rise is an indicator that our planet is warming. Much of the world's population lives on or near the coast, and rising seas are something worth watching. Sea level can rise for two reason...

  20. Meteorological buoy observations from the central Iceland Sea

    NASA Astrophysics Data System (ADS)

    Harden, B. E.; Renfrew, I. A.; Petersen, G. N.

    2015-04-01

    We present the first continuous in situ atmospheric observations from the central Iceland Sea collected from a meteorological buoy deployed for a 2 year period between 23 November 2007 and 21 August 2009. We use these observations to evaluate the ERA-Interim reanalysis product and demonstrate that it represented low-level meteorological fields and surface turbulent fluxes in this region very well. The buoy observations showed that moderate to strong winds were common from any direction, while wind speeds below 5 ms-1 were relatively rare. The observed low-level air temperature and surface heat fluxes were related to the wind direction with cold-air outbreaks most common from the northwest. Mean wintertime turbulent heat fluxes were modest (<60 Wm-2), but the range was substantial. High heat flux events, greater than 200 Wm-2, typically occurred every 1-2 weeks in the winter, with each event lasting on average 2.5 days with an average total turbulent heat flux of 200 Wm-2 out of the ocean. The most pronounced high heat flux events over the central Iceland Sea were associated with cold-air outbreaks from the north and west forced by a deep Lofoten Low over the Norwegian Sea.

  1. Influence of the North Atlantic on climate change in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Glok, Natalia; Alekseev, Genrikh; Smirnov, Aleksander; Vyasilova, Anastasia

    2015-04-01

    This study is based on the observations taken from the meteorological archives, satellite and historic visual observations of sea ice, global SST, data of water temperature in the upper layer on the section in the Barents Sea. For processing data was used factor analysis, calculation of correlation matrices with different delay between the Barents Sea and selected areas in North Atlantic. It is shown that the inflow of Atlantic water into the Barents Sea has a major influence on the climate of the region and its changes affect the variations of all climate characteristics. Decadal and interannual changes of air temperature in the Barents Sea are closely related (correlation over 0.8) with temperature of water, coming from the Norwegian Sea. The effect of these changes is seen in the air temperature in the Kara Sea. Atlantic water inflow especially impact on winter sea ice in the Barents Sea. The correlation between the average water temperature at section along the Kola meridian and sea ice extent in the Barents Sea in May reaches values of -0.86. To enhance the predictive capability established dependence, the study was extended to the area of the North Atlantic, where temperature anomalies are formed. In the North Atlantic from the equator to 80 ° N were identified 6 areas where the average annual SST anomalies are associated with SST anomalies and sea ice extent (SIE) in the Barents Sea. Detailed analysis with monthly SST from HadISST for 1951 - 2013 identified two areas with the greatest influence on the Barents Sea. One area is the northern region of the Gulf Stream and other is the equatorial region. The corresponding delays amounted to 26 months and 4-5 years. The relationship between changes AMO index, averaged over August-October, and SIE in the Barents Sea in January is evaluated. Correlation coefficient between them with 3 year delay is -0.54. Implemented study revealed the importance of teleconnection between SST anomalies in the North Atlantic and SST and SIE in the Barents Sea with a delay of several months to several years, which have prognostic significance. This research is supported by Ministry of Education and Science of the Russia (project RFMEFI61014X0006)

  2. More on Sea Turtles and Seaweed

    ERIC Educational Resources Information Center

    Xin, Tian

    2005-01-01

    "Sea turtle" and "seaweed"--otherwise known as "returnee from abroad" and "unemployed from abroad," respectively-- are a pair of popular new terms that are innately connected. In this article, the author discusses the common plight faced by "sea turtles" and "seaweeds" who returned from abroad to work in China. The author describes the experiences…

  3. Mesoscale Eddies in the Solomon Sea

    NASA Astrophysics Data System (ADS)

    Hristova, H. G.; Kessler, W. S.; McWilliams, J. C.; Molemaker, M. J.

    2011-12-01

    Water mass transformation in the strong equatorward flows through the Solomon Sea influences the properties of the Equatorial Undercurrent and subsequent cold tongue upwelling. High eddy activity in the interior Solomon Sea seen in altimetric sea surface height (SSH) and in several models may provide a mechanism for these transformations. We investigate these effects using a mesoscale (4-km resolution) sigma-coordinate (ROMS) model of the Solomon Sea nested in a basin solution, forced by a repeating seasonal cycle, and evaluated against observational data. The model generates a vigorous upper layer eddy field; some of these are apparently shed as the New Guinea Coastal Undercurrent threads through the complex topography of the region, others are independent of the strong western boundary current. We diagnose the scales and vertical structure of the eddies in different parts of the Solomon Sea to illuminate their generation processes and propagation characteristics, and compare these to observed eddy statistics. Hypotheses tested are that the Solomon Sea mesoscale eddies are generated locally by baroclinic instability, that the eddies are shed as the South Equatorial Current passes around and through the Solomon Island chain, that eddies are generated by the New Guinea Coastal Undercurrent, or that eddies occurring outside of the Solomon Sea propagate into the Solomon Sea. These different mechanisms have different implications for the resulting mixing and property fluxes. They also provide different interpretations for SSH signals observed from satellites (e.g., that will be observed by the upcoming SWOT satellite).

  4. Jabiru find stirs Timor Sea interest

    SciTech Connect

    Not Available

    1984-07-20

    The Jabiru oil field in the Timor Sea has been the hot topic around Australia since its discovery by Broken Hill Pty. in late 1983. Because of the potential of the area, Australia and Indonesia have resumed talks on the boundary disputes of the Timor Sea. The new Australian Resource Rent Tax (RRT) is also discussed in relation to this area.

  5. Atlantic Air-Sea Interaction Revisited

    NASA Astrophysics Data System (ADS)

    Rodwell, M. J.

    INTRODUCTION DATA AND MODELS THE ANALYSIS METHOD ATMOSPHERIC FORCING OF NORTH ATLANTIC SEA SURFACE TEMPERATURES NORTH ATLANTIC SEA SURFACE TEMPERATURE FORCING OF THE ATMOSPHERE Observational Evidence Model Results POTENTIAL SEASONAL PREDICTABILITY BASED ON THE ATMOSPHERE GENERAL - CIRCULATION MODEL CONCLUSIONS AND DISCUSSION REFERENCES

  6. The application of ERTS imagery to monitoring Arctic sea ice. [mapping ice in Bering Sea, Beaufort Sea, Canadian Archipelago, and Greenland Sea

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.

    1974-01-01

    The author has identified the following significant results. Because of the effect of sea ice on the heat balance of the Arctic and because of the expanding economic interest in arctic oil and minerals, extensive monitoring and further study of sea ice is required. The application of ERTS data for mapping ice is evaluated for several arctic areas, including the Bering Sea, the eastern Beaufort Sea, parts of the Canadian Archipelago, and the Greenland Sea. Interpretive techniques are discussed, and the scales and types of ice features that can be detected are described. For the Bering Sea, a sample of ERTS-1 imagery is compared with visual ice reports and aerial photography from the NASA CV-990 aircraft. The results of the investigation demonstrate that ERTS-1 imagery has substantial practical application for monitoring arctic sea ice. Ice features as small as 80-100 m in width can be detected, and the combined use of the visible and near-IR imagery is a powerful tool for identifying ice types. Sequential ERTS-1 observations at high latitudes enable ice deformations and movements to be mapped. Ice conditions in the Bering Sea during early March depicted in ERTS-1 images are in close agreement with aerial ice observations and photographs.

  7. Teaching Wide Sargasso Sea in New Jersey

    ERIC Educational Resources Information Center

    Jolley, Susan Arpajian

    2005-01-01

    High school teacher Susan Arpajian Jolley emphasizes experience and understanding by using the related novels "Wide Sargasso Sea" and "Jane Eyre" to help her students travel into unfamiliar cultural territory. "Wide Sargasso Sea" relates to Caribbean history and culture, feminism, race relations, colonialism, and personal identity.

  8. LITE Measurements of Sea Surface Directional Reflectance

    NASA Technical Reports Server (NTRS)

    Menzies, Robert T.; Tratt, David M.; Hunt, William H.

    1997-01-01

    The dependence of sea surface directional reflectance on surface wind speed from space-based lidar measurements of sea surface backscatter. In particular lidar measurements in the nidir angle range from 10-30 degrees appear to be most sensitive to surface wind speed variability in the regime below 10m/s.

  9. More on Sea Turtles and Seaweed

    ERIC Educational Resources Information Center

    Xin, Tian

    2005-01-01

    "Sea turtle" and "seaweed"--otherwise known as "returnee from abroad" and "unemployed from abroad," respectively-- are a pair of popular new terms that are innately connected. In this article, the author discusses the common plight faced by "sea turtles" and "seaweeds" who returned from abroad to work in China. The author describes the experiences

  10. Tritium level along Romanian Black Sea Coast

    SciTech Connect

    Varlam, C.; Stefanescu, I.; Popescu, I.; Faurescu, I.

    2008-07-15

    Establishing the tritium level along the Romanian Black Sea Coast, after 10 years of exploitation of the nuclear power plant from Cernavoda, is a first step in evaluating its impact on the Black Sea ecosystem. The monitoring program consists of tritium activity concentration measurement in sea water and precipitation from Black Sea Coast between April 2005 and April 2006. The sampling points were spread over the Danube-Black Sea Canal - before the locks Agigea and Navodari, and Black Sea along the coast to the Bulgarian border. The average tritium concentration in sea water collected from the sampling locations had the value of 11.1 {+-} 2.1 TU, close to tritium concentration in precipitation. Although an operating nuclear power plant exists in the monitored area, the values of tritium concentration in two locations are slightly higher than those recorded elsewhere. To conclude, it could be emphasized that until now, Cernavoda NPP did not had any influence on the tritium concentration of the Black Sea Shore. (authors)

  11. Sea Stars Underwater Offshore Northern California

    USGS Multimedia Gallery

    Three sea stars on a rock, surrounded by a sandy seafloor littered with broken shells. Each sea star is approx. 10 - 15 cm (4-6 inches) across. Image acquired 4.5 km (3 miles) offshore Pigeon Point, southern San Mateo County, California at a depth of 52 meters....

  12. Modelling the extinction of Steller's sea cow.

    PubMed

    Turvey, S T; Risley, C L

    2006-03-22

    Steller's sea cow, a giant sirenian discovered in 1741 and extinct by 1768, is one of the few megafaunal mammal species to have died out during the historical period. The species is traditionally considered to have been exterminated by 'blitzkrieg'-style direct overharvesting for food, but it has also been proposed that its extinction resulted from a sea urchin population explosion triggered by extirpation of local sea otter populations that eliminated the shallow-water kelps on which sea cows fed. Hunting records from eighteenth century Russian expeditions to the Commander Islands, in conjunction with life-history data extrapolated from dugongs, permit modelling of sea cow extinction dynamics. Sea cows were massively and wastefully overexploited, being hunted at over seven times the sustainable limit, and suggesting that the initial Bering Island sea cow population must have been higher than suggested by previous researchers to allow the species to survive even until 1768. Environmental changes caused by sea otter declines are unlikely to have contributed to this extinction event. This indicates that megafaunal extinctions can be effected by small bands of hunters using pre-industrial technologies, and highlights the catastrophic impact of wastefulness when overexploiting resources mistakenly perceived as 'infinite'. PMID:17148336

  13. Color Difference in Bering Sea Phytoplankton Blooms

    NASA Technical Reports Server (NTRS)

    2002-01-01

    There is considerable color variation in the phytoplankton blooms in the Bering Sea -- from the aquamarine west of Nunivak Island to the almost reddish patch west of St. Matthew Island to the green eddy astride the International dateline at 60 North latitude and 178 East longitude. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  14. Metagenomic sequencing of two salton sea microbiomes.

    PubMed

    Hawley, Erik R; Schackwitz, Wendy; Hess, Matthias

    2014-01-01

    The Salton Sea is the largest inland body of water in California, with salinities ranging from brackish freshwater to hypersaline. The lake experiences high nutrient input, and its surface water is exposed to temperatures up to 40C. Here, we report the community profiles associated with surface water from the Salton Sea. PMID:24459270

  15. Metagenomic Sequencing of Two Salton Sea Microbiomes

    PubMed Central

    Hawley, Erik R.; Schackwitz, Wendy

    2014-01-01

    The Salton Sea is the largest inland body of water in California, with salinities ranging from brackish freshwater to hypersaline. The lake experiences high nutrient input, and its surface water is exposed to temperatures up to 40C. Here, we report the community profiles associated with surface water from the Salton Sea. PMID:24459270

  16. The South Pole and the Ross Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image shows a rare clear view of the South Pole (lower right) and the Ross Sea, Antarctica. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) acquired the scene on December 26, 2001. The geographic South Pole is located in the center of Antarctica, at an altitude of 2,900 meters (9,300 feet). It rests on a continent-wide ice sheet that is 2,870 m thick, with the underlying bedrock only 30 m (98 feet) above sea level. The ice underlying the South Pole is as much as 140,000 years old, and is currently accumulating at about 82 cm (32 inches) per year. Roughly 2,500 km (1,550 miles) away is the green water of the Ross Sea, which indicates the presence of large numbers of phytoplankton. This is a highly productive part of the world's oceans. Also note the ice gathered around McMurdo Sound, seen toward the lefthand shoreline of the Ross Sea, at the edge of the Ross Ice Shelf. According to National Science Foundation researchers, this ice is making it difficult for penguins to reach their food supply. Separating the continental Antarctic ice sheet from the Ross Sea are the Queen Maud Mountains and the Ross Ice Shelf. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  17. The strength anisotropia of sea ice

    SciTech Connect

    Evdokimov, G.N.; Rogachko, S.I.

    1994-12-31

    The hydraulic-engineering structure calculations of sea ice formation force require the sea ice strength data. The strength characteristics values and the types of sea ice formations in view of water depth define the type and the design of future structures in each particular region of supposed construction. The most objective information on the sea ice physical and technical properties can be obtained by field investigations ad the existing methods of their calculations refer to a great number of errors. The accumulated bank of data on studying the sea ice formation strength properties show one that ice as a natural material is of great crystalline structure variety. The level ice fields have a number of particularities. The crystal sizes increase in ice thickness. The crystals consist of fresh-water thin plates 0.5--0.6 mm in thickness oriented by pickle-water interlayers. Difference in thickness of the sea ice cover structure is one of the main causes of the changes strength characteristics layer. Besides that the sea ice strength depends upon the destroying force direction in reference to crystal orientation which characterizes the sea ice anisotropia as a material.

  18. Sea ice thickness variability in the Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Haas, C.; Bublitz, A.

    2014-12-01

    Sea ice in the Canadian Beaufort Sea has retreated strongly in recent summers, raising interest in its role for the Arctic climate and eco system, and in allowing access for shipping and offshore resources extraction both in Canada and in Alaskan waters further downstream. However, little is known about the thickness of its first- and multiyear ice regimes at the end of winter which are important in preconditioning the ice cover for summer retreat. Here we present results from spring-time airborne electromagnetic ice thickness surveys performed since 2009 over hundreds of kilometers of various first- and multiyear ice regimes. Surveys are complemented by satellite radar imagery allowing regional extrapolation of results. Results show large regional thickness variability with bands of first-year ice in the south and east, of heavily deformed old multiyear ice further north, and of younger multiyear ice in the Canada Basin further to the Northwest. This regional variability is hard to capture with moored ice thickness echo sounders. While the regions of multiyear ice have become thinner overall, there is little evidence for thinning of first-year ice despite later fall freeze-up. This may be related to a thinner snow cover and supports hypotheses about the resilience of first-year ice in a warmer Arctic. Due to the spatial extent of the surveys our data provide unique opportunities for the validation of satellite and airborne radar and laser altimeter and microwave radiometer ice thickness retrievals for which we will show a few examples. We have also analysed the occurrence of extreme ice features and hummock fields and show that these occur frequently both in the first- and multiyear ice regimes. These continue to pose hazards for marine infrastructure.

  19. Influence of the North Atlantic Oscillation on the North Sea and the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Markovic, Michaela; Httl-Kabus, Sabine; Klein, Birgit; Mikolajewicz, Uwe; Sein, Dmitry; Grger, Matthias

    2013-04-01

    We present an analysis of the effects of climate variability in the Northeast Atlantic (inflow region at ~60 N), North Sea and Baltic Sea from a simulation with the coupled climate model MPIOM/REMO/ECHAM5 (ocean model of the Max-Planck-Institute, Hamburg) for the A1B scenario. The particular grid structure of the MPIOM allows for the combination of a global ocean model with a regional high resolution area and resolves scales of 5-15 km in the North Sea. Furthermore, the MPIOM can be run in a regionally coupled mode using the REMO regional atmosphere model and includes a module for ocean tides. Accordingly, the model simulations allow us to explore how the currently observed warming and freshing trend in the North Sea and the Baltic Sea evolves during the 21st century. The distribution of temperature and salinity on the shallow shelf sea shows a substantial warming and freshing in future throughout the seasons with considerable regional variability. The change visible in the whole water column in the North Sea and the Baltic Sea is affected by changes in atmospheric forcing. The main driver the North Atlantic Oscillation impacts on the circulation, the sea level and water mass properties of the North Sea and the Baltic Sea. To determine the influence of the model results the monthly winter NAO + and NAO - composites have been calculated, to investigate the relation.

  20. Dynamic response of the Black Sea elevation to intraseasonal fluctuations of the Mediterranean sea level

    NASA Astrophysics Data System (ADS)

    Volkov, Denis L.; Johns, William E.; Belonenko, Tatyana V.

    2016-01-01

    Response of the Black Sea elevation to intraseasonal sea level changes in the Mediterranean is studied using satellite altimetry data and a linear analytical model. Satellite observations show that the nonseasonal sea level in the Black Sea (?1) is coherent with that in the Aegean and Marmara Seas (?0) but lags behind them by 10-40 days at subannual periods. The observed time lag is mainly due to friction that constrains the exchange through the Bosphorus Strait. Using realistic friction and characteristic ?0 forcing in the model, we find that the amplitude of ?1 reaches the amplitude of ?0 at about 1 year period, and the time lag increases from 10 to 22 days at periods 50-250 days. Freshwater fluxes, atmospheric pressure, and to a smaller extent the along-strait wind also influence the Black Sea elevation, but sea level fluctuations in the Mediterranean appear to be the dominant forcing mechanism.

  1. On the measure of sea ice area from sea ice concentration data sets

    NASA Astrophysics Data System (ADS)

    Boccolari, Mauro; Parmiggiani, Flavio

    2015-10-01

    The measure of sea ice surface variability provides a fundamental information on the climatology of the Arctic region. Sea ice extension is conventionally measured by two parameters, i.e. Sea Ice Extent (SIE) and Sea Ice Area (SIA), both parameters being derived from Sea Ice Concentration (SIC) data sets. In this work a new parameter (CSIA) is introduced, which takes into account only the compact sea-ice, which is defined as the sea-ice having concentration at least equal the 70%. Aim of this study is to compare the performances of the two parameters, SIA and CSIA, in analyzing the trends of three monthly time-series of the whole Arctic region. The SIC data set used in this study was produced by the Institute of Environmental Physics of the University of Bremen and covers the period January 2003 - December 2014, i.e. the period in which the data set is built using the new AMSR passive microwave sensor.

  2. Long term trends in the sea surface temperature of the Black Sea

    NASA Astrophysics Data System (ADS)

    Shapiro, G. I.; Aleynik, D. L.; Mee, L. D.

    2010-01-01

    There is growing understanding that recent deterioration of the Black Sea ecosystem was partly due to changes in the marine physical environment. This study uses high resolution 0.25 climatology to analyze sea surface temperature variability over the 20th century in two contrasting regions of the sea. Results show that the deep Black Sea was cooling during the first three quarters of the century and was warming in the last 15-20 years; on aggregate there was a statistically significant cooling trend. The SST variability over the Western shelf was more volatile and it does not show statistically significant trends. The cooling of the deep Black Sea is at variance with the general trend in the North Atlantic and may be related to the decrease of westerly winds over the Black Sea, and a greater influence of the Siberian anticyclone. The timing of the changeover from cooling to warming coincides with the regime shift in the Black Sea ecosystem.

  3. Long term trends in the sea surface temperature of the Black Sea

    NASA Astrophysics Data System (ADS)

    Shapiro, G. I.; Aleynik, D. L.; Mee, L. D.

    2010-05-01

    There is growing understanding that recent deterioration of the Black Sea ecosystem was partly due to changes in the marine physical environment. This study uses high resolution 0.25 climatology to analyze sea surface temperature variability over the 20th century in two contrasting regions of the sea. Results show that the deep Black Sea was cooling during the first three quarters of the century and was warming in the last 15-20 years; on aggregate there was a statistically significant cooling trend. The SST variability over the Western shelf was more volatile and it does not show statistically significant trends. The cooling of the deep Black Sea is at variance with the general trend in the North Atlantic and may be related to the decrease of westerly winds over the Black Sea, and a greater influence of the Siberian anticyclone. The timing of the changeover from cooling to warming coincides with the regime shift in the Black Sea ecosystem.

  4. The South China Sea Deep: Introduction

    NASA Astrophysics Data System (ADS)

    Wang, Pinxian; Li, Qianyu; Dai, Minhan

    2015-12-01

    The South China Sea (SCS) has increasingly become a global focus in ocean research and hydrocarbon explorations. Over the last two decades, at least 17 international cruises including two ODP/IODP expeditions were conducted in the SCS, and more than 2000 exploratory wells were drilled (Wang et al., 2014a). While its sedimentary basins on the continental shelf and slope are explored for offshore resources, the deep basin below 3500 m in depth that overlies the basaltic oceanic crust preserves the key to understanding their formation and development. In order to better understand the life history and functional system of the marginal sea, a major research program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep" for short, was launched in January 2011 by the National Natural Science Foundation (NSFC) of China. This venture represents the first ever large-scale basic-research program in ocean science in the country (Wang, 2012).

  5. Ecological role of purple sea urchins.

    PubMed

    Pearse, John S

    2006-11-10

    Sea urchins are major components of marine communities. Their grazing limits algal biomass, and they are preyed upon by many predators. Purple sea urchins (Strongylocentrotus purpuratus) are among the best studied species. They live in environments that alternate between two stable states: luxuriant, species-rich kelp forests and sea urchin-dominated "barrens." The transition from one state to the other can be initiated by several factors, including the abundance of algal food, predators, storm intensities, and incidence of disease. Purple sea urchins compete with other grazers, some of which are important fishery resources (such as abalones and red sea urchins), and they are harvested for scientific research. Revelations from their genome will lead to a better understanding of how they maintain their ecological importance, and may in turn enhance their economic potential. PMID:17095690

  6. Wind-driven circulation in Titan's seas

    NASA Astrophysics Data System (ADS)

    Tokano, Tetsuya; Lorenz, Ralph D.

    2015-04-01

    Circulation in Titan's seas forced by wind is simulated by an ocean circulation model using surface wind data predicted by a global circulation model. Wind-driven circulation is insignificant throughout much of the annual cycle, but becomes significant from late spring to late summer, when the wind stress becomes strong. The large-scale circulation in summer is predominantly southward near the sea surface and northward near the sea bottom. The sea surface current can get as fast as 5 cms-1 in some areas. Titan's rotation affects the vertical structure of sea currents in the form of an Ekman spiral if the wind is strong. The maximum wind set-up at the shores is of the same order of magnitude as the tidal range. Wind stirring may reduce thermal stratification in summer, but may be unable to destroy stratification of methane-rich liquids on top of ethane-rich liquids that can result from imbalances between evaporation and precipitation.

  7. Wind-driven circulation in Titan's seas

    NASA Astrophysics Data System (ADS)

    Tokano, Tetsuya; Lorenz, Ralph D.

    2015-01-01

    Circulation in Titan's seas forced by wind is simulated by an ocean circulation model using surface wind data predicted by a global circulation model. Wind-driven circulation is insignificant throughout much of the annual cycle but becomes significant from late spring to late summer, when the wind stress becomes strong. The large-scale circulation in summer is predominantly southward near the sea surface and northward near the sea bottom. The sea surface current can get as fast as 5 cms-1 in some areas. Titan's rotation affects the vertical structure of sea currents in the form of an Ekman spiral if the wind is strong. The maximum wind setup at the shores is of the same order of magnitude as the tidal range. Wind stirring may reduce thermal stratification in summer but may be unable to destroy stratification of methane-rich liquids on top of ethane-rich liquids that can result from imbalances between evaporation and precipitation.

  8. Brine-ecosystem interactions in sea ice

    NASA Astrophysics Data System (ADS)

    Vancoppenolle, M.; Bitz, C. M.; Fichefet, T.; Goosse, H.; Lancelot, C.; Tison, J.

    2010-12-01

    Microalgae grow in brine inclusions in sea ice. Previous sea ice-ecosystem models neglect brine-microalgae interactions, prescribing the location of the microbial communities. In this study, a sea ice model with explicit brine dynamics coupled to a simple nutrient-phytoplankton (N-P) module (diatoms and dissolved silicates) is introduced. The model predicts bottom and surface microalgal populations. In fall, brine convection in cooling ice supplies nutrients, which favors microalgal growth. In early summer, the vertical brine density profile in warmer ice stabilizes, nutrient supply shuts off, which prevents further biomass building. Sensitivity tests in an idealized Antarctic pack ice configuration suggest that mode of microalgal transport within brine (passive or active) induces important population differences. This study is a step toward a more realistic sea ice-ecosystem model, which is required to understand the role of sea ice and associated ecosystems in global biogeochemical cycles.

  9. Quark sea asymmetries of the octet baryons

    SciTech Connect

    Sharma, Neetika; Dahiya, Harleen

    2010-06-01

    The effects of 'quark sea' in determining the flavor structure of the octet baryons have been investigated in the chiral constituent quark model ({chi}CQM). The {chi}CQM is able to qualitatively generate the requisite amount of quark sea and is also known to provide a satisfactory explanation of the proton spin and related issues in the nonperturbative regime. The Bjorken scaling variable x has been included phenomenologically in the sea quark distribution functions to understand its implications on the quark sea asymmetries like d(x)-u(x), d(x)/u(x), and Gottfried integral for the octet baryons. The results strengthen the importance of quark sea at lower values of x.

  10. Volga River Delta and Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color MODIS image from May 10, 2002, captures Russia's Volga River (running south through the center) emptying into the northern portion of the Caspian Sea. The waters of the Caspian Sea are quite murky in this image, highlighting the water quality problems plaguing the sea. The sea is inundated with sewage and industrial and agricultural waste, which is having measurable impact on human health and wildlife. According reports from the Department of Energy, in less than a decade the sturgeon catch dropped from 30,000 tons to just over 2,000 tons. National and international groups are currently joining together to find strategies of dealing with the environmental problems of the Caspian Sea. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  11. A Detailed Radiometric Chronological Framework for Nordic Seas Ocean-Ice Sheet Interactions Spanning 50-150 Ka BP

    NASA Astrophysics Data System (ADS)

    Brendryen, J.; Edwards, R. L.; Haflidason, H.; Cheng, H.; Grasmo, K. J.; Sejrup, H. P.

    2014-12-01

    Chronological control of sedimentary deposits is a key to do paleoclimatic interpretations of proxy records and to compare them with records from other archives. Beyond the reach of radiocarbon dating there are however few options for developing chronological control. We present a detailed radiometrical-based chronological framework of a Norwegian Sea core archive that records ocean-ice sheet interactions in the Nordic Seas covering the time span 50-150 ka BP. The chronology is based on a detailed multi-proxy and multi-archive alignment of high resolution records from the Norwegian Sea and precisely radiometric dated speleothem ?18O record from both China and the Alps. This approach utilizes the close and well documented millennial and multi-centennial scale coupling between the North Atlantic climate variability (recorded in the Norwegian Sea records, the Greenland ice cores and in the Alpine speleothems) and the Asian Monsoon system recorded in the Chinese speleothem ?18O. One intriguing feature of the Norwegian Sea record is that it often is more similar to the Chinese speleothem records than to the Greenland ice core records. The alignment is aided by a tephrostratigraphic link to the Greenland ice cores which provide an independent test of the age model and alignment. Uncertainties are addressed by Bayesian age-depth modeling. The radiometric-based age model and the quantified uncertainties enable an independent comparison between the Nordic Seas ocean-ice sheet interaction and other absolutely dated records such as U/Th dated sea-level indices and orbital parameters. This improves our ability to interpret the ocean-ice sheet interactions of the polar north in a global context over this time span that comprises a glacial-interglacial cycle.

  12. Geomagnetic Navigation in Sea Turtles

    NASA Astrophysics Data System (ADS)

    Lohmann, K.; Putman, N.; Lohmann, C.

    2011-12-01

    Young loggerhead sea turtles (Caretta caretta) from eastern Florida undertake a transoceanic migration in which they gradually circle the north Atlantic Ocean before returning to the North American coast. Newly hatched turtles (hatchlings) begin the migration with a 'magnetic map' in which regional magnetic fields function as navigational markers and elicit changes in swimming direction at crucial geographic boundaries. In laboratory experiments, young turtles that had never before been in the ocean were exposed to fields like those that exist at various, widely separated locations along their transoceanic migratory route. Turtles responded by swimming in directions that would, in each case, help them remain within the North Atlantic gyre currents and advance along the migratory pathway. The results demonstrate that turtles can derive both longitudinal and latitudinal information from the Earth's field, and provide strong evidence that hatchling loggerheads inherit a remarkably elaborate set of responses that function in guiding them along their open-sea migratory route. For young sea turtles, couplings of oriented swimming to regional magnetic fields appear to provide the fundamental building blocks from which natural selection can sculpt a sequence of responses capable of guiding first-time ocean migrants along complex migratory routes. The results imply that hatchlings from different populations in different parts of the world are likely to have magnetic navigational responses uniquely suited for the migratory routes that each group follows. Thus, from a conservation perspective, turtles from different populations are not interchangeable. From an evolutionary perspective, the responses are not incompatible with either secular variation or magnetic polarity reversals. As Earth's field gradually changes, strong selective pressure presumably acts to maintain an approximate match between the responses of hatchlings and the fields that exist at critical points along the migratory pathway at any point in time. Although responses to regional fields might be rendered useless during occasional periods of rapid field change associated with magnetic polarity reversals or excursions, these sporadic events do not preclude the evolution of magnetic responses during the intervening and usually much longer intervals when Earth's field changes more slowly and is relatively stable.

  13. International Arctic Seas Assessment Project.

    PubMed

    Sjblom, K L; Salo, A; Bewers, J M; Cooper, J; Dyer, R S; Lynn, N M; Mount, M E; Povinec, P P; Sazykina, T G; Schwarz, J; Scott, E M; Sivintsev, Y V; Tanner, J E; Warden, J M; Woodhead, D

    1999-09-30

    The International Atomic Energy Agency responded to the news that the former Soviet Union had dumped radioactive wastes in the shallow waters of the Arctic Seas, by launching the International Arctic Seas Assessment Project in 1993. The project had two objectives: to assess the risks to human health and to the environment associated with the radioactive wastes dumped in the Kara and Barents Seas; and to examine possible remedial actions related to the dumped wastes and to advise on whether they are necessary and justified. The current radiological situation in the Arctic waters was examined to assess whether there is any evidence for releases from the dumped waste. Potential future releases from the dumped wastes were predicted, concentrating on the high-level waste objects containing the major part of the radionuclide inventory of the wastes. Environmental transport of released radionuclides was modelled and the associated radiological impact on humans and the biota was assessed. The feasibility, costs and benefits of possible remedial measures applied to a selected high-level waste object were examined. Releases from identified dumped objects were found to be small and localised to the immediate vicinity of the dumping sites. Projected future annual doses to members of the public in typical local population groups were very small, less than 1 microSv--corresponding to a trivial risk. Projected future doses to a hypothetical group of military personnel patrolling the foreshore of the fjords in which wastes have been dumped were higher, up to 4 mSv/year, which still is of the same order as the average annual natural background dose. Moreover, since any of the proposed remedial actions were estimated to cost several million US$ to implement, remediation was not considered justified on the basis of potentially removing a collective dose of 10 man Sv. Doses calculated to marine fauna were insignificant, orders of magnitude below those at which detrimental effects on fauna populations might be expected to occur. Remediation was thus concluded not to be warranted on radiological grounds. PMID:10568273

  14. Complex Stratigraphic Evolution of the Red Sea

    NASA Astrophysics Data System (ADS)

    Almalki, Khalid A.; Mahmud, Syed A.

    2015-04-01

    The Red Sea rift, separates the African and the Arabian continents, and is considered a type location of a juvenile rift-related small ocean. Geological studies and drilling programs date back to more than half a century yet very little is known about the stratigraphic evolution to the wider geological community. Following the arrival of the Afar plume at the late Oligocene (ca 30 Ma) the southern Red Sea underwent rapid extension culminating in extended continental crust or seafloor spreading, which stalled during the early Miocene at the central Red Sea due to either slowing of the convergence between Arabia and Eurasia or the onset of the Arabian plate passive margin collision with Eurasia. The mainland pan of the region was uplifted, resulting in the development of the Red Sea erosional escarpment. Shelf sedimentation (Middle-late Miocene to Pleistocene successions) then ensued and covered oceanic and continental crust. The present day spreading centre resumed in the southern Red Sea at 5 Ma and has been propagating northward until the present-day. However, detailed analysis of the basin shows a more complex pattern of basin development with late Oligocene succession restricted to the western Red Sea coast and the southern sectors. Well data suggest that up to 4 km of sediments exist in the southern Red Sea shallowing upward to the northern sector; 3 km or more of this section consists of Miocene evaporates, which contains intercalated anhydrite and shale horizons. These Miocene evaporates are overlain by Quaternary reefal limestone, and recent volcanic rocks restricted to the central axial trough zone of the Red Sea. In this study extensive well data that is well spread in the area was used to evaluate the stratigraphic architecture, build-ups, and local controls on deposition. Potential stratigraphic models have been developed. The distribution of stratigraphy in the Red Sea area yields complex correlation, with unique depositional characteristics in discrete zones within the Red Sea basin.

  15. Sea Ice Biogeochemistry: A Guide for Modellers

    PubMed Central

    Tedesco, Letizia; Vichi, Marcello

    2014-01-01

    Sea ice is a fundamental component of the climate system and plays a key role in polar trophic food webs. Nonetheless sea ice biogeochemical dynamics at large temporal and spatial scales are still rarely described. Numerical models may potentially contribute integrating among sparse observations, but available models of sea ice biogeochemistry are still scarce, whether their relevance for properly describing the current and future state of the polar oceans has been recently addressed. A general methodology to develop a sea ice biogeochemical model is presented, deriving it from an existing validated model application by extension of generic pelagic biogeochemistry model parameterizations. The described methodology is flexible and considers different levels of ecosystem complexity and vertical representation, while adopting a strategy of coupling that ensures mass conservation. We show how to apply this methodology step by step by building an intermediate complexity model from a published realistic application and applying it to analyze theoretically a typical season of first-year sea ice in the Arctic, the one currently needing the most urgent understanding. The aim is to (1) introduce sea ice biogeochemistry and address its relevance to ocean modelers of polar regions, supporting them in adding a new sea ice component to their modelling framework for a more adequate representation of the sea ice-covered ocean ecosystem as a whole, and (2) extend our knowledge on the relevant controlling factors of sea ice algal production, showing that beyond the light and nutrient availability, the duration of the sea ice season may play a key-role shaping the algal production during the on going and upcoming projected changes. PMID:24586604

  16. The Caribbean conundrum of Holocene sea level.

    NASA Astrophysics Data System (ADS)

    Jackson, Luke; Mound, Jon

    2014-05-01

    In the tropics, pre-historic sea-level curve reconstruction is often problematic because it relies upon sea-level indicators whose vertical relationship to the sea surface is poorly constrained. In the Caribbean, fossil corals, mangrove peats and shell material dominate the pre-historic indicator record. The common approach to reconstruction involves the use of modern analogues to these indicators to establish a fixed vertical habitable range. The aim of these reconstructions is to find spatial variability in the Holocene sea level in an area gradually subsiding (< 1.2 mm yr-1) due the water loading following the deglaciation of the Laurentide ice sheet. We construct two catalogues: one of published Holocene sea-level indicators and the other of published, modern growth rates, abundance and coverage of mangrove and coral species for different depths. We use the first catalogue to calibrate 14C ages to give a probabilistic age range for each indicator. We use the second catalogue to define a depth probability distribution function (pdf) for mangroves and each coral species. The Holocene indicators are grouped into 12 sub-regions around the Caribbean. For each sub-region we apply our sea-level reconstruction, which involves stepping a fixed-length time window through time and calculating the position (and rate) of sea-level (change) using a thousand realisations of the time/depth pdfs to define an envelope of probable solutions. We find that the sub-regional relative sea-level curves display spatio-temporal variability including a south-east to north-west 1500 year lag in the arrival of Holocene sea level to that of the present day. We demonstrate that these variations are primarily due to glacial-isostatic-adjustment induced sea-level change and that sub-regional variations (where sufficient data exists) are due to local uplift variability.

  17. Arctic and Antarctic sea ice and climate

    NASA Astrophysics Data System (ADS)

    Barreira, S.

    2014-12-01

    Principal Components Analysis in T-Mode Varimax rotated was performed on Antarctic and Arctic monthly sea ice concentration anomalies (SICA) fields for the period 1979-2014, in order to investigate which are the main spatial characteristics of sea ice and its relationship with atmospheric circulation. This analysis provides 5 patterns of sea ice for inter-spring period and 3 patterns for summer-autumn for Antarctica (69,2% of the total variance) and 3 different patterns for summer-autumn and 3 for winter-spring season for the Arctic Ocean (67,8% of the total variance).Each of these patterns has a positive and negative phase. We used the Monthly Polar Gridded Sea Ice Concentrations database derived from satellite information generated by NASA Team algorithm. To understand the links between the SICA and climate trends, we extracted the mean pressure and, temperature field patterns for the months with high loadings (positive or negative) of the sea ice patterns that gave distinct atmospheric structures associated with each one. For Antarctica, the first SICA spatial winter-spring pattern in positive phase shows a negative SICA centre over the Drake Passage and north region of Bellingshausen and Weddell Seas together with another negative SICA centre over the East Indian Ocean. Strong positive centres over the rest of the Atlantic and Indian Oceans basins and the Amundsen Sea are also presented. A strong negative pressure anomaly covers most of the Antarctic Continent centered over the Bellingshausen Sea accompanied by three positive pressure anomalies in middle-latitudes. During recent years, the Arctic showed persistent associations of sea-ice and climate patterns principally during summer. Our strongest summer-autumn pattern in negative phase showed a marked reduction on SICA over western Arctic, primarily linked to an overall increase in Arctic atmospheric temperature most pronounced over the Beaufort, Chukchi and East Siberian Seas, and a positive anomaly of pressure over Greenland.

  18. Sea ice-albedo climate feedback mechanism

    SciTech Connect

    Schramm, J.L.; Curry, J.A.; Ebert, E.E.

    1995-02-01

    The sea ice-albedo feedback mechanism over the Arctic Ocean multiyear sea ice is investigated by conducting a series of experiments using several one-dimensional models of the coupled sea ice-atmosphere system. In its simplest form, ice-albedo feedback is thought to be associated with a decrease in the areal cover of snow and ice and a corresponding increase in the surface temperature, further decreasing the area cover of snow and ice. It is shown that the sea ice-albedo feedback can operate even in multiyear pack ice, without the disappearance of this ice, associated with internal processes occurring within the multiyear ice pack (e.g., duration of the snow cover, ice thickness, ice distribution, lead fraction, and melt pond characteristics). The strength of the ice-albedo feedback mechanism is compared for several different thermodynamic sea ice models: a new model that includes ice thickness distribution., the Ebert and Curry model, the Mayjut and Untersteiner model, and the Semtner level-3 and level-0 models. The climate forcing is chosen to be a perturbation of the surface heat flux, and cloud and water vapor feedbacks are inoperative so that the effects of the sea ice-albedo feedback mechanism can be isolated. The inclusion of melt ponds significantly strengthens the ice-albedo feedback, while the ice thickness distribution decreases the strength of the modeled sea ice-albedo feedback. It is emphasized that accurately modeling present-day sea ice thickness is not adequate for a sea ice parameterization; the correct physical processes must be included so that the sea ice parameterization yields correct sensitivities to external forcing. 22 refs., 6 figs., 1 tab.

  19. Coherent sea level variation in and around the Sea of Okhotsk

    NASA Astrophysics Data System (ADS)

    Nakanowatari, Takuya; Ohshima, Kay I.

    2014-08-01

    We investigated the seasonal and interannual variations of the sea level in and around the Sea of Okhotsk and their causes, based on tide gauge and satellite altimeter data. The sea level all along the coastal region of the Sea of Okhotsk is found to be dominated by the seasonal variation with a maximum in winter and a minimum in summer, which cannot be explained by the annual cycle of atmospheric heat flux and pressure. This sea level variation appears to reflect ocean current variations. Both the Arrested Topographic Waves (ATWs) caused by alongshore wind stress and the Sverdrup transport by wind stress curl show corresponding seasonal variations. Seasonal amplitude of the sea level is relatively large along Sakhalin Island with a tendency of a larger amplitude toward the south. This meridional dependence is consistent with the ATWs, but not with the Sverdrup transport in the Sea of Okhotsk. Seasonal variation of the geostrophic current velocity expected from the sea level variation is comparable to that of the observed nearshore current and is consistent with the theoretical ATW transport. It is also revealed that, on an interannual timescale, the wintertime sea level fluctuates quite coherently all around the Sea of Okhotsk and further along the East Kamchatka and Oyashio coasts in the North Pacific. The altimeter data clearly show that this coherent sea level variation is trapped over the coastal and continental shelf regions with depths shallower than 1000 m. The wintertime sea levels have a higher correlation with the ATW transport than with the Sverdrup transport in the Sea of Okhotsk and the upstream East Kamchatka coast. All these suggest that the interannual sea level variation along the coastal and shelf regions in winter, as well as the seasonal variation, is mainly caused by the ATWs (coastal trapped current forced by the alongshore wind stress). The wintertime Sverdrup transport, raised by the previous studies, is the secondary contributor to these variations.

  20. SEAS Classroom to Sea Labs: New Directions for Ridge 2000 Communitywide Education Outreach

    NASA Astrophysics Data System (ADS)

    Goehring, L.

    2005-12-01

    Lessons learned from the two year SEAS pilot program emphasize that student participation in deep-sea research is an important motivator in student learning. Further, SEAS students experience a paradigm shift in understanding evidence-based reasoning and the process of scientific discovery. At the same time, we have learned that fostering authentic student investigations within the confines of the academic year is challenging and only fits classrooms with some academic flexibility. As a result, this year, SEAS will focus on the new Classroom to Sea Lab as a means to help foster student inquiry in the secondary school science classroom. The Classroom to Sea Lab invites student participation in deep-sea research but does so without requiring students to identify and propose suitable sea-going experiments. Classroom to Sea labs are designed to feature current deep-sea research, and emphasize critical skills in laboratory techniques, data collection and analysis, and scientific reporting. Labs are conducted in the classroom (by students) and at sea (by scientists for the students), resulting in parallel datasets for comparison. Labs also feature the work of practicing scientists. An annual Classroom to Sea Report Fair invites students to summarize their findings and submit written analyses for scientist feedback and prizes, emphasizing the importance of communications skills in science. This year, the SEAS program will feature the Shallow-water vs. Deep-sea Vent Mussel Classroom to Sea lab. In this lab, students explore differences in mussel anatomy and feeding strategies, and understand how chemosynthetic symbionts function in this animal. The lab instructs students to dissect shallow-water mussels and measure the proportion of gill tissue to total body tissue. Students are also instructed to download a dataset of vent mussel measurements and compare average proportions. Finally, students are invited to submit their analyses of the lab to the on-line Report Fair sponsored by the Ridge 2000 research community. A primary goal of SEAS is to excite and engage student learners by involving them in actual research in the extreme environments of the deep-sea. The program depends on the contributions of multiple scientists within the Ridge 2000 community. Scientists field student questions during the Ask-a-Scientist email forum, serve as Report Reviewers, are featured in ``Scientist Spotlights,'' host educators during cruises to conduct at-sea portions of a lab, and help develop new labs. It is community involvement that makes the SEAS program possible and so exciting and motivating for students.

  1. SEAS: Student Experiments At Sea - An Education Outreach Pilot Program Sponsored by the Ridge2000 Program

    NASA Astrophysics Data System (ADS)

    Goehring, L.

    2004-12-01

    SEAS is a pilot program for middle and high school students who want to learn science by doing science. SEAS students study the deep sea hydrothermal vent environment and learn to ask questions about this exciting, relatively unexplored world, just as researchers do. SEAS students also learn how to answer their own questions through the process of scientific investigation. With the SEAS program, students have the opportunity to participate in the actual discovery process, along side deep-sea researchers. SEAS builds upon the successes of programs like Dive&Discover and Extreme2000, which demonstrated the capability deep-sea scientists have in engaging students with live research. SEAS extends this concept by inviting students to participate in deep-sea research through formal proposal and report competitions. SEAS challenges students to higher levels of achievement. A curriculum, developed by teachers expert in the translation of scientific inquiry in the classroom, prepares students to participate. SEAS was concept-tested during the 2003-2004 school year, with 14 pilot teachers and approximately 800 students. Twenty Ridge2000 scientists contributed their time and expertise to the SEAS program in its first year. Five student proposals were selected and conducted at sea in April during a Ridge2000 research cruise to the East Pacific Rise. All results were posted to the SEAS website (http://www.ridge2000.org/SEAS/) during the cruise, and students were invited to analyze data for their final reports. Final student reports, along with scientists comments were also posted. During the 2004-2005 school year, SEAS will be evaluated for its impact on student learning and attitudes toward science. The benefits of SEAS to the Ridge2000 scientific community are many. Scientists are invited to contribute in a variety of ways, all of which help satisfy the requirement of NSFs Broader Impacts Criterion. They may contribute time and expertise by answering student questions and reviewing student proposals and reports. They may choose to host the student research on their cruise. By sharing the load, no one scientist is burdened, nor expected to contribute additional funding. The Ridge2000 Program oversees the development, execution and dissemination of SEAS, helping make outreach efficient and easy for scientists.

  2. Is sea salt in ice cores a proxy of past sea ice extent?

    NASA Astrophysics Data System (ADS)

    Levine, James; Wolff, Eric; Frey, Markus; Jenkins, Hazel; Jones, Anna; Yang, Xin

    2014-05-01

    A number of marine, coastal and ice core proxies have been used to try to assess the past extent of sea ice. Sea salt has been proposed as a proxy for past ice extent, at least in the Southern Ocean. The idea is that the sea ice surface itself holds a source of sea salt, that is stronger than the source from the open ocean it replaces. That a sea ice source exists is apparent from observations of the ratio of sulphate to sodium in coastal aerosol and snow samples. While the idea behind using sea salt as a proxy is attractive, and leads to sensible inferences, many doubts remain. Firstly the exact nature of the source remains uncertain, and secondly it is not clear if ice extent, as opposed to changes in atmospheric transport and lifetime, would dominate variability in the ice core record of sea salt. Here we use a model of atmospheric transport and chemistry (p-TOMCAT) to assess the consequences of a sea ice source, focussing particularly on a source that has been proposed to arise from the sublimation of salty blowing snow. We will briefly report some new observations from a winter cruise, that will allow us to comment on the likelihood that blowing snow does pose a significant source. We will then present results from the model (implemented using existing parameters). The model has been run with seasonally and interannually varying sea ice extent and meteorology for the Antarctic, tracking, at different ice core sites, the concentration that arises from the open ocean and sea ice sources. We have already shown that the model, after tuning, is able to reproduce the magnitude and seasonal cycle of sea salt at a range of sites globally. By varying each component separately we explore which factors (sea ice presence, wind speed at source, transporting winds) and which source regions control the delivery of sea salt to sites in Antarctica. Such work suggests that sea salt cannot be used as a sea ice proxy on interannual timescales, but may be suitable on longer timescales. By employing much larger sea ice extents, such as at the last glacial maximum (LGM), we find a strong increase in concentration at ice core sites when ice extent increases. The increase in modelled sea salt concentration tails off sharply as ice approaches the LGM extent, so that the sensitivity of the proxy is greater at lower ice extents, for example in interglacials. We will discuss the implications of this work for the proposed use of sea salt as a sea ice proxy.

  3. Constraints on the timing and duration of methane derived authigenic carbonate formation in the North Sea and the Barents Sea from U-Th dating

    NASA Astrophysics Data System (ADS)

    Condon, D. J.; Sahy, D.; Crmire, A.; Lepland, A.; Noble, S. R.; Chand, S.; Brunstad, H.

    2014-12-01

    Assessment of the tempo of past methane discharges from sub-surface reservoirs, and their relationship to external forcings such as ice-sheet collapse, is in part hindered by the lack of robust age constraints. Methane-derived authigenic carbonate (MDAC) crusts exhibiting characteristic 13C-depleted isotopic signatures were collected from several seepage sites on the Norwegian continental shelf, including sites in the North Sea, the Norwegian Sea and the Barents Sea and a combined petrological, stable isotope and geochronology study has been carried out. MDAC samples exhibited a range of mineralogical compositions and contexts, from carbonate-cemented silt, sand, and gravel, to cavities lined with relatively pure (>90%) late-stage aragonitic infills. The U-Th dating results constrain the main episode of carbonate crust formation in the Barents and Norwegian seas during the time interval between 14 and 5 ka. Based on analyses of matrix-forming CaCO3 and multiple generations of cavity fills individual, up to 15 cm thick crusts may represent at least 3.3 kyr of growth. Cavity fills representing focussed fluid flow post-date the main interval of crust formation by ca. 2 kyr and sub-sampling of these layered cavity fills revealed resolvable growth histories, on the order of 1 kyr. The dating of the main phases of MDAC formation suggest that the methane seepage along the northern Norwegian margin was coincident with the collapse of the Scandinavian ice sheet and deglaciation of the area. The precipitation of studied North Sea carbonate crusts occurred more recently, from 6 to 1 ka, suggesting that their formation is unrelated to the glacial history of the area and gas hydrate stability. These data, combined with published data from other MDAC sites (e.g., Gulf of Mexico, Hydrate Ridge, Sea of Japan) demonstrate the utility of constraining the temporal evolution of hydrate and/or hydrocarbon system related fluid flow from the subsurface to the ocean/atmosphere, and assessing variation within and between different basins and areas (e.g., glaciated vs. non-glaciated terranes).

  4. Sea-Salt Aerosol Forecasts Compared with Wave and Sea-Salt Measurements in the Open Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Kishcha, P.; Starobinets, B.; Bozzano, R.; Pensieri, S.; Canepa, E.; Nicovic, S.; di Sarra, A.; Udisti, R.; Becagli, S.; Alpert, P.

    2012-03-01

    Sea-salt aerosol (SSA) could influence the Earth's climate acting as cloud condensation nuclei. However, there were no regular measurements of SSA in the open sea. At Tel-Aviv University, the DREAM-Salt prediction system has been producing daily forecasts of 3-D distribution of sea-salt aerosol concentrations over the Mediterranean Sea (http://wind.tau.ac.il/salt ina/salt.html). In order to evaluate the model performance in the open sea, daily modeled concentrations were compared directly with SSA measurements taken at the tiny island of Lampedusa, in the Central Mediterranean. In order to further test the robustness of the model, the model performance over the open sea was indirectly verified by comparing modeled SSA concentrations with wave height measurements collected by the ODAS Italia 1 buoy and the Llobregat buoy. Model-vs.-measurement comparisons show that the model is capable of producing realistic SSA concentrations and their day-to- day variations over the open sea, in accordance with observed wave height and wind speed.

  5. Sea-Salt Aerosol Forecasts Compared with Wave and Sea-Salt Measurements in the Open Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Kishcha, P.; Starobinets, B.; Bozzano, R.; Pensieri, S.; Canepa, E.; Nickovie, S.; di Sarra, A.; Udisti, R.; Becagli, S.; Alpert, P.

    2012-03-01

    Sea-salt aerosol (SSA) could influence the Earth's climate acting as cloud condensation nuclei. However, there were no regular measurements of SSA in the open sea. At Tel-Aviv University, the DREAM-Salt prediction system has been producing daily forecasts of 3-D distribution of sea-salt aerosol concentrations over the Mediterranean Sea (http://wind.tau.ac.il/saltina/ salt.html). In order to evaluate the model performance in the open sea, daily modeled concentrations were compared directly with SSA measurements taken at the tiny island of Lampedusa, in the Central Mediterranean. In order to further test the robustness of the model, the model performance over the open sea was indirectly verified by comparing modeled SSA concentrations with wave height measurements collected by the ODAS Italia 1 buoy and the Llobregat buoy. Model-vs.-measurement comparisons show that the model is capable of producing realistic SSA concentrations and their day-today variations over the open sea, in accordance with observed wave height and wind speed.

  6. Sea level rise and submarine mass failures on open continental margins

    NASA Astrophysics Data System (ADS)

    Smith, D. E.; Harrison, S.; Jordan, J. T.

    2013-12-01

    Submarine mass failures (which include submarine slides or submarine landslides) occur widely on open continental margins. Understanding their cause is of great importance in view of the danger that they can pose both to coastal populations through tsunamis and to the exploitation of ocean floor resources through mass movement of the sea floor. Present knowledge of the causes of submarine mass failures is briefly reviewed, focussing on the role of sea level rise, a process which has previously only infrequently been cited as a cause. It is argued that sea level rise could easily have been involved in at least some of these events by contributing to increased overpressure in sediments of the continental margin whilst causing seismic activity. The Holocene Storegga Slide off South West Norway may have been partly caused by the early Holocene sea level rise in the area, accentuated by meltwater flux from the discharges of Lake Agassiz-Ojibway in North America. Relative sea level rise increased water loading on the Norwegian continental margin, increasing overpressure in the sediments and also causing seismic activity, triggering the Holocene Storegga Slide. Given that some forecasts of future sea level rise are not greatly different from rises which obtained during the early Holocene, the implications of rising sea levels for submarine mass failures in a global warming world are considered.

  7. The oxygen isotope composition of water masses within the North Sea

    NASA Astrophysics Data System (ADS)

    Harwood, Andrew J. P.; Dennis, Paul F.; Marca, Alina D.; Pilling, Graham M.; Millner, Richard S.

    2008-06-01

    Based on measurements of the 18O isotope composition of 247 samples collected over a 3-year period we have assessed the oxygen isotope composition of water masses in the North Sea. This is the first ?18O data set that covers the entire North Sea basin. The waters lie on a mixing line: ?18O ( VSMOW) = -9.300 + 0.274( S) with North Atlantic sub-polar mode water (SPMW) and surface waters, and Baltic Sea water representing the saline and freshwater end members respectively. Patterns exhibited in surface and bottom water ?18O distributions are representative of the general circulation of the North Sea. Oxygen-18 enriched waters from the North Atlantic enter the North Sea between Scotland and Norway and to a lesser extent through the English Channel. In contrast, oxygen-18 depleted waters mainly inflow from the Baltic Sea, the rivers Rhine and Elbe, and to a lesser degree, the Norwegian Fjords and other river sources. Locally the ?18O-salinity relationship will be controlled by the isotopic composition of the freshwater inputs. However, the range of local freshwater compositions around the North Sea basin is too narrow to characterise the relative contributions of individual sources to the overall seawater composition. This dataset provides important information for a number of related disciplines including biogeochemical research and oceanographic studies.

  8. Plastic litter in the sea.

    PubMed

    Depledge, M H; Galgani, F; Panti, C; Caliani, I; Casini, S; Fossi, M C

    2013-12-01

    On June 2013 a workshop at the University of Siena (Italy) was organized to review current knowledge and to clarify what is known, and what remains to be investigated, concerning plastic litter in the sea. The content of the workshop was designed to contribute further to the European Marine Strategy Framework Directive (MSFD) following an inaugural workshop in 2012. Here we report a number of statements relevant to policymakers and scientists that was overwhelming agreement from the participants. Many might view this as already providing sufficient grounds for policy action. At the very least, this early warning of the problems that lie ahead should be taken seriously, and serve as a stimulus for further research. PMID:24157269

  9. Family conflicts in the sea.

    PubMed

    Kamel, Stephanie Jill; Grosberg, Richard K; Marshall, Dustin J

    2010-08-01

    In sexually reproducing organisms, conflicts of interest among family members are inevitable. The intensity of these conflicts depends upon the opportunities for parents and offspring to interact and the level of promiscuity. Despite the acknowledged role of family conflict in the evolutionary ecology of terrestrial organisms, its influence in the marine realm has largely been ignored. Nevertheless, marine organisms exhibit a wide range of reproductive and developmental modes through which sexual, sibling, and parent-offspring conflicts can manifest. Moreover, the existence of multiple mating in these species increases the likelihood, as well as the degree, of these conflicts. Consequently, many puzzling aspects of evolution in the sea, from life-history variation to diversification, could be clarified through the lens of conflict theory. PMID:20557975

  10. Deep South China Sea circulation

    NASA Astrophysics Data System (ADS)

    Wang, Guihua; Xie, Shang-Ping; Qu, Tangdong; Huang, Rui Xin

    2011-03-01

    The analysis of an updated monthly climatology of observed temperature and salinity from the U.S. Navy Generalized Digital Environment Model reveals a basin-scale cyclonic circulation over the deep South China Sea (SCS). The cyclonic circulation lies from about 2400 m to the bottom. The boundary current transport of the cyclonic circulation is around 3.0 Sv. Our results suggest that the cyclonic circulation is mainly forced by the Luzon overflow, with bottom topography playing an important role. The structures of potential temperature, salinity, and potential density in the deep SCS are consistent with the existence of the cyclonic circulation. Specifically, low salinity water is found in the interior region west of Luzon Island, and surrounded by saline Pacific water in boundary current regions to the north, west and southwest. Our results show the potential density distribution and the corresponding cyclonic circulation in deep SCS are primarily controlled by salinity variations in the deep basin.

  11. Tides of the Caribbean Sea

    SciTech Connect

    Kjerfve, B.

    1981-05-20

    Analysis of tidal characteristics from 45 gauge locations indicates that the Caribbean Sea has a microtidal range, for the most part between 10 and 20 cm. The tide is primarily either mixed semidiurnal or mixed diurnal but a substantial section from Puerto Rico to Venezuela experiences diurnal tides. Empirical charts of six component tides (M/sub 2/, S/sub 2/, N/sub 2/, K/sub 1/, O/sub 1/, and P/sub 1/) show local detail of phase and amplitude. Each of the semidiurnal component tides is characterized by anticlockwise rotating amphidromes centered in the eastern Caribbean. There is evidence of strong radiational forcing of the S/sub 2/ tide in the south-western Caribbean. The diurnal component tides are largely uniform in both phase and amplitude for most of the western and central Caribbean. However, the diurnal phases increase rapidly towards the northwest and the Yucatan Channel.

  12. Sea level change: a philosophical approach

    NASA Astrophysics Data System (ADS)

    Leinfelder, R.; Seyfried, H.

    1993-07-01

    The present Cenozoic era is an icehouse episode characterized by a low sea level. Since the beginning of the industrial revolution, the human race has been emitting greenhouse gases, increasing the global atmospheric temperature, and causing a rise in sea level. If emissions continue to increase at the present rate, average global temperatures may rise by 1.5C by the year 2050, accompanied by a rise of about 30 cm in sea level. However, the prediction of future climatic conditions and sea level is hampered by the difficulty in modelling the interactions between the lithosphere, kryosphere, biosphere and atmosphere; in addition, the buffering capacity of our planet is still poorly understood. As scientists cannot offer unambiguous answers to simple questions, sorcerer's apprentices fill in the gaps, presenting plans to save planet without inconveniencing us. The geological record can help us to learn about the regulation mechanisms of our planet, many of which are connected with or expressed as sea level changes. Global changes in sea level are either tectono-eustatic or glacioeustatic. Plate tectonic processes strongly control sea levels and climate in the long term. There is a strong feed-back mechanism between sea level and climate; both can influence and determine each other. Although high sea levels are a powerful climatic buffer, falling sea levels accelerate climatic accentuation, the growth of the polar ice caps and will hence amplify the drop in sea level. Important sources of fossil greenhouse gases are botanic CO2 production, CO2 released by volcanic activity, and water vapour. The latter is particularly important when the surface area of the sea increases during a rise in sea level (maritime greenhouse effect). A volcanogenic greenhouse effect (release of volcanogenic CO2) is possibly not equally important, as intense volcanic activity may take place both during icehouse episodes as well as during greenhouse episodes. The hydrosphere, land vegetation and carbonate platforms are major CO2 buffers which may both take up and release CO2. CO2 can be released from the ocean due to changes in the pCO2 caused by growth of coral reefs and by uptake of CO2-rich freshwater from karst provinces. Efficient sinks of CO2 are the weathering products of silicate rocks; long-term sinks are organic deposits caused by regional anoxic events which preferrably develop during sea level rises and highstands; and coal-bearing strata. Deposition of limestone also removes CO2 from the atmospheric-hydrospheric cycle at a long term. Biotic crises are often related to either sea-level lows or sea-level highs. Long-term sea-level lows, characteristic of glacial periods, indicate cooling as major cause of extinction. During verly long-lasting greenhouse episodes the sea level is very high, climate and circulation systems are stable and biotic crises often develop as a consequence of oxygen depletion. On land, niche-splitting, complex food web structures and general overspecialization of biota will occur. Whether the crisis is caused by a single anoxic event (e.g. in the Late Devonian) or a disturbance by an asteroid impact (e.g. the Cretaceous/Tertiary boundary), it will only trigger total collapse of an ecosystem if a large part of it was already in decline. The regulatory mechanisms and buffers are thermodynamically extremely efficient if they are given sufficient time in which to deploy their power. However, after major catastrophes the re-establishment of successful ecosystems will take millions of years. The present rate of sea level and associated temperature rise is much too fast to be compensated and buffered by the network of natural controls. It is likely that the transitional time towards a new steady state will be an extremely variable and chaotic episode of unpredictable duration.

  13. Thermodynamic properties of sea air

    NASA Astrophysics Data System (ADS)

    Feistel, R.; Kretzschmar, H.-J.; Span, R.; Hagen, E.; Wright, D. G.; Herrmann, S.

    2009-10-01

    Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphere-ocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS), and have been adopted in 2009 for oceanography by IOC/UNESCO. In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as ''sea air'' here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well. The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.

  14. Thermodynamic properties of sea air

    NASA Astrophysics Data System (ADS)

    Feistel, R.; Wright, D. G.; Kretzschmar, H.-J.; Hagen, E.; Herrmann, S.; Span, R.

    2010-02-01

    Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphere-ocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS), and have been adopted in 2009 for oceanography by IOC/UNESCO. In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as "sea air" here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well. The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.

  15. Arctic sea ice thickness change

    NASA Astrophysics Data System (ADS)

    Haas, C.; Hendricks, S.

    2011-12-01

    Area and extent of Arctic sea ice are shrinking rapidly, but rates and regional patterns of this decline are still not well understood. Knowledge of spatial and temporal ice thickness variability and change is essential for a better understanding and prediction of the present and future fate of Arctic sea ice. Airborne electromagnetic ice thickness surveys obtained sporadically since the 1990s and more systematically in recent years showed thinning rates of 20 to 50 % per decade over the observation period in the region of the North Pole, with minimum thicknesses of only 0.9 m observed in 2007. In contrast, modal thicknesses of more than 4 m were observed between the North Pole and Canada, showing pronounced thinning only in recent years, with modal thicknesses of around 3 m or less observed in 2008 and 2011. The latter may be related to continuing reductions of the area of old multiyear ice residing in the Arctic Ocean, which is now receding to a narrow fringe along the coast of North America. This presentation will provide a summary of past results, and will discuss these in light of reductions of the area of old ice deduced from satellite and buoy data. We will focus on results from new airborne surveys obtained in 2010 and 2011, with ever increasing regional coverage and range due to the utilization of fixed-wing aircraft. From these long-range surveys small-scale regional variability and spatial thickness gradients emerge which give new insights into the disappearance of old and thick ice regimes.

  16. Crustal architecture and basin evolution in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Faleide, J.; Team, P.

    2008-12-01

    The Barents Sea comprises a wide range of crustal and basin architectures that formed in response to different geological processes. In particular there are major differences between the western and eastern Barents Sea. The eastern Barents Sea is underlain by a wide (300-400 km) and deep (15-20 km) sedimentary basin that extends for more than 1000 km in a north-south direction. The basin formed by rapid subsidence in Late Permian-Early Triassic times. There are few signs of faulting associated with basin formation and it does not look like typical rift basins. There is a clear spatial correlation between the deep East Barents Sea Basin and the thickness of a high-velocity body in the upper mantle, and there is a temporal link between the main phase of basin formation and Siberian Traps magmatism. However, the links between the shallow and deep structure and any regional effects of the igneous activity are not well understood. The deep East Barents Sea Basin was filled by thick Triassic sediments prograding westwards from uplifted source area in the SE (Urals). Subsidence analysis assuming crustal stretching/thinning as the main driving force for sedimentary basin formation implies large Beta-values and a relatively hot basin scenario. However, taking into account the dimensions of the broad sag basin and the general lack of faulting it is not obvious whether this is a valid assumption. Alternatively, we are studying the role of phase transitions in the crust and upper mantle and how they could have contributed to subsidence in a colder basin scenario. In the western Barents Sea we find more typical rift basins formed in response to at least three major post-Caledonian rift phases: Carboniferous, Late Jurassic-Early Cretaceous, and Late Cretaceous-early Paleogene. The rifting activity migrated westwards through successive tectonic phases. Carboniferous rifting affected the entire western Barents Sea and gave rise to NE-SW to N-S trending horst and graben structures following a Caledonian basement grain. Late Jurassic-Early Cretaceous oblique extension in the deep SW Barents Sea basins was linked to the North Atlantic-Arctic plate tectonic evolution. A Late Cretaceous-Early Paleogene mega-shear system along the western Barents Sea-Svalbard margin (De Geer Zone) linked rifting, breakup and initial opening of the Norwegian-Greenland Sea and the Arctic Eurasia Basin. Most Barents Sea basins have also been affected by regional magmatism, compressional deformation and inversion and/or late uplift and erosion. These overprinting processes may have had important implications for the basin evolution and the petroleum systems. The different basin architectures and development are compared and discussed in relation to timing, deep crustal and upper mantle structures, and histories of vertical motion, basin filling and temperature.

  17. Crustal architecture and basin evolution in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Faleide, J. I.; Petrobar Team

    2009-04-01

    The Barents Sea comprises a wide range of crustal and sedimentary basin architectures that formed in response to different geological processes. In particular there are major differences between the western and eastern Barents Sea. The eastern Barents Sea is underlain by a wide (300-400 km) and deep (15-20 km) sedimentary basin that extends for more than 1000 km in a north-south direction. The basin formed by rapid subsidence in Late Permian-Early Triassic times. There are few signs of faulting associated with basin formation and it does not look like typical rift basins. There is a clear spatial correlation between the deep East Barents Sea Basin and the thickness of a high-velocity body in the upper mantle, and there is a temporal link between the main phase of basin formation and Siberian Traps magmatism. However, the links between the shallow and deep structure and any regional effects of the igneous activity are not well understood. The deep East Barents Sea Basin was filled by thick Triassic sediments prograding westwards from uplifted source area in the SE (Urals). Subsidence analysis assuming crustal stretching/thinning as the main driving force for sedimentary basin formation implies large Beta-values and a relatively hot basin scenario. However, taking into account the dimensions of the broad sag basin and the general lack of faulting it is not obvious whether this is a valid assumption. Alternatively, we are studying the role of phase transitions in the crust and upper mantle and how they could have contributed to subsidence in a colder basin scenario. In the western Barents Sea we find more typical rift basins formed in response to at least three major post-Caledonian rift phases: Carboniferous, Late Jurassic-Early Cretaceous, and Late Cretaceous-early Paleogene. The rifting activity migrated westwards through successive tectonic phases. Carboniferous rifting affected the entire western Barents Sea and gave rise to NE-SW to N-S trending horst and graben structures following a Caledonian basement grain. Late Jurassic-Early Cretaceous oblique extension in the deep SW Barents Sea basins was linked to the North Atlantic-Arctic plate tectonic evolution. A Late Cretaceous-Early Paleogene mega-shear system along the western Barents Sea-Svalbard margin (De Geer Zone) linked rifting, breakup and initial opening of the Norwegian-Greenland Sea and the Arctic Eurasia Basin. Most Barents Sea basins have also been affected by regional magmatism, compressional deformation and inversion and/or late uplift and erosion. These overprinting processes may have had important implications for the basin evolution and the petroleum systems. The different basin architectures and development are compared and discussed in relation to timing, deep crustal and upper mantle structures, and histories of vertical motion, basin filling and temperature.

  18. Review of critical factors for SEA implementation

    SciTech Connect

    Zhang Jie Christensen, Per; Kornov, Lone

    2013-01-15

    The implementation process involved in translating Strategic Environmental Assessment (SEA) intention into action is vital to an effective SEA. Many factors influence implementation and thus the effectiveness of an SEA. Empirical studies have identified and documented some factors influencing the implementation of an SEA. This research is fragmented, however, and it is still not clear what are the most critical factors of effective SEA performance, and how these relate to different stages of the implementation process or other contextual circumstances. The paper takes its point of departure in implementation theory. Firstly, we introduce implementation theory, and then use it in practice to establish a more comprehensive model related to the stages in the implementation process. Secondly, we identify the critical factors in order to see how they are related to the different stages of SEA or are more general in character. Finally we map the different critical factors and how they influence the overall results of an SEA. Based on a literature review, we present a comprehensive picture of the critical factors and where they are found in the process. We conclude that most of the critical factors identified are of a more general character influencing the SEA process as such, while only one out of four of these factors relates to the specific stages of the SEA. Based on this mapping we can sketch a picture of the totality of critical factors. In this study 266 notions of critical factors were identified. Seen at the level of notions of critical factors, only 24% of these relate to specific stages while for 76% the critical factors are of a more general nature. These critical factors interact in complex ways and appear in different combinations in different stages of the implementation process so tracing the cause and effect is difficult. The pervasiveness of contextual and general factors also clearly suggests that there is no single way to put SEA into practice. The paper identifies some of the critical factors for effective SEA implementation, but further research is still needed to conclude which factors are more critical than others, just as the contingencies on which they depend are not easy to unravel. - Highlights: Black-Right-Pointing-Pointer The research on critical factors influencing SEA implementation is fragmented. Black-Right-Pointing-Pointer The critical factors are used to discuss 'hot-spots' in the implementation process. Black-Right-Pointing-Pointer Critical factors are just as broad as the concept of effectiveness. Black-Right-Pointing-Pointer Both stage and general factors are relevant in explaining the effectiveness of SEA.

  19. On the seasonal variability of the eddy field in the eastern part of the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Andersson, M.; Orvik, K. O.; Lacasce, J. H.; Mauritzen, C.; Koszalka, I.

    2009-04-01

    The Norwegian Atlantic current (NwAC) transports warm and saline Atlantic water northward toward the Arctic Ocean, as a poleward eastern boundary current. The Atlantic water occupies a wider and deeper domain in the Lofoten Basin than farther south and north. It comprises the major-heat reservoir in the Norwegian Sea with contact with the atmosphere and is an important area for cooling. In the Nordic seas the Lofoten Basin is a region of high mesoscale activity. We infer that the fluid parcels are not going directly poleward, but are experiencing detours as in, for instance, horizontal recirculations. Such detours cause the fluid parcels to be in contact with the atmosphere for longer periods, increasing cooling. In the POLEWARD project, SVP drifters have been deployed to track fluid parcels in the Norwegian Atlantic Current as it traverses the Nordic Seas. In the period June 2007 to October 2008, 118 ARGOS-tracked drifters, drogued at 15 meters depth, were deployed in the NwAC. We augment this data with historical data from SVP drifters in the same region. The interpolated and quality controlled position data have been used to construct maps of the mean velocity field at 15 m depth, the eddy kinetic energy and the principal axes of variance for summer and winter seasons. The drifters reveal strong, localized current systems along the Norwegian coast, the continental margins and their extensions to the Barents Sea and Spitsbergen. The eddy kinetic energy reveals stronger variability in the Lofoten Basin area, particularly in the wintertime. The variance axes show significant variations, both spatially and seasonally.

  20. In situ stress and natural fracture distribution in the Ekofisk Field, North Sea

    SciTech Connect

    Teufel, L W; Farrell, H E

    1990-01-01

    In situ stress and natural fractures have been mapped across the structural dome that forms the Ekofisk field in the Norwegian sector of the North Sea. The reservoir rock is chalk and a natural fracture system forms the primary conductive path for produced hydrocarbons and injected fluids. In situ stress measurements have been made using hydraulic fractures and anelastic strain recovery measurements of oriented core. 36 refs., 21 figs., 2 tabs.

  1. Investigation of sea level trends and the effect of the north atlantic oscillation (NAO) on the black sea and the eastern mediterranean sea

    NASA Astrophysics Data System (ADS)

    Ozgenc Aksoy, Aysegul

    2016-03-01

    The North Atlantic Oscillation (NAO) has significant effects on sea levels, weather, and climate. In this study, the sea level trends and the effects of the North Atlantic Oscillation Indices (NAOI) on annual mean sea level data were assessed for the Black Sea and the Eastern Mediterranean Sea. The trends of sea level and NAOI were determined using Mann-Kendall dimensionless z statistics. Generally, upward sea level trends were detected for the Black Sea and the Eastern Mediterranean Sea. In the Black Sea, significant and continuous upward trends were detected after the year 1950. Weaker trends were detected for the Eastern part of the Mediterranean Sea. Sea level trends were correlated with trends in NAO indices; negative correlations were detected for the Black Sea, whereas positive correlations were found for the Eastern Mediterranean Sea. Paired t tests were performed to determine the turning points for all sea level data sets. The value of t was positive for all data sets, which means that the mean value of the data set before the turning point was smaller than the mean value of the data set after the turning point.

  2. Polar Seas Oceanography: An Integrated Case Study of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Harms, Ingo

    2004-02-01

    What strikes first when browsing through this book is that the main title is misleading. Polar Seas Oceanography is, first of all, a book on ``an integrated case study of the Kara Sea,'' as the subtitle says. For readers who are interested more generally in polar oceanography, the book is probably the wrong choice. The Kara Sea is a rather shallow shelf sea within the Arctic Ocean, located between the Barents Sea to the west and the Laptev Sea to the east. The importance of the Kara Sea is manifold: climate change issues like ice formation and freshwater runoff, environmental problems from dumping of radioactive waste or oil exploitation, and finally, the Northern Sea route, which crosses large parts of the Kara Sea, underline the economical and ecological relevance of that region. In spite of severe climate conditions, the Kara Sea is relatively well investigated. This was achieved through intense oceanographic expeditions, aircraft surveys, and polar drift stations. Russian scientists from the Arctic and Antarctic Research Institute (AARI) carried out a major part of this outstanding work during the second half of the last century.

  3. Regional Long-Term Sea Level and Sea Surface Temperature Characteristics from Satellite Observations

    NASA Astrophysics Data System (ADS)

    Andersen, O. B.; Knudsen, P.; Beckley, B.

    2006-07-01

    For a the large portion of the world's population liv ing in coastal zones forecasts of long- term sea lev el change is importan t for a var iety of environmen tal and socio- economic r easons. Satellite altimetry offers a unique opportunity for improving our knowledge about glob al and r egional sea level change on bo th global and reg ional scale. Joint TOPEX/PO SEIDON(T/P) +JASON-1 sea level observations and Reyno lds AVH RR sea surface temperature observ ations over th e most recen t 12 years hav e qualitativ ely been used to study regional correlations between long-term changes in sea level and sea surface temper ature. Long-term is here tak en to be lin ear signals in the 12-year time per iod Consistent in creases in both sea level and sea surface temp eratures ar e found in large parts of the world's oceans over this per iod. In the Indian Ocean and particularly th e Pacif ic Ocean , the trends in both sea level and temper ature are domin ated by the larg e changes associated w ith th e El N io Southern Oscillation (ENSO) . Co mparison with similar trend estimates u sing only 8 years of satellite data shows the incr eased decoupling with ENSO and th e imp act of inter-annual variability on sea lev el tr end estimates.

  4. Fluid and electromagnetic transport in sea ice

    NASA Astrophysics Data System (ADS)

    Gully, Adam Spence

    Covering 7-10% of the Earth's ocean surface, sea ice is both an indicator and agent of climate change. The sea ice cover controls the exchange of heat, momentum, and gases between the ocean and atmosphere. As a material, sea ice is a polycrystalline composite consisting of a pure ice host containing brine, air, and solid salt inclusions. This dissertation examines sea ice processes that are important to climate studies. In particular, we investigate the fluid transport properties of sea ice, which mediate melt pond evolution and ice pack reflectance, snow-ice formation, nutrient replenishment for microbial communities, and the evolution of salinity profiles. We also examine the electromagnetic monitoring of these processes, which rely on some knowledge of the effective electrical properties of sea ice. Columnar sea ice is effectively impermeable to fluid flow below a 5% brine volume fraction, yet is permeable for brine volume fractions above this threshold value. In two different experiments conducted in the Arctic and Antarctic, we have found that this critical transition in fluid flow at the brine connectivity threshold displays a strong electrical signature. The sea ice conductivity data are accurately explained by percolation theory with a universal critical exponent of 2. The data also indicate marked changes in the conductivity profile with the onset of surface ponding. Further, resistance data from classical four-probe Wenner arrays on the surfaces of ice floes in Antarctica were used to indirectly reconstruct the conductivity profiles with depth, involving both the horizontal and vertical components. We note the close agreement with the actual data for some models and the inadequacy of others. Additionally, a network model for the electrical conductivity of sea ice is developed, which incorporates statistical measurements of the brine microstructure. The numerical simulations are in close agreement with direct measurements we made in Antarctica on the vertical conductivity of first year sea ice. Together, these results lay the foundation for electromagnetic monitoring of transport phenomena in sea ice and help provide a rigorous basis for electromagnetic methods to obtain sea ice thickness data. We also modify traditional percolation models for columnar sea ice, hypothesizing that granular sea ice has a percolation threshold near a 10% brine volume fraction. This modified percolation model is then in excellent agreement with our fluid permeability field data taken in Antarctica, where granular ice is a significant component of the ice cover. Here we also develop theoretical bounds on two extensive sets of effective complex permittivity sea ice data taken in the Arctic and Antarctic. The first set of bounds assumes only knowledge of the brine volume fraction or porosity, and the second set further assumes statistical isotropy of the microstructure. We obtain excellent agreement between theory and experiment, and are able to observe the apparent violation of the isotropic bounds as the vertically oriented microstructure becomes increasingly connected for higher porosities. Moreover, these bounds are inverted to obtain estimates of the porosity from the measurements of the effective complex permittivity. We find that the temporal variations of the reconstructed porosity, which is directly related to temperature, closely follow the actual behavior. Additionally, an analytic method for obtaining bounds on the effective complex permittivity of polycrystalline composite materials is developed and applied to the effective complex permittivity of sea ice. Here we use mean single crystal orientation data and single crystal complex permittivity tensor data to obtain polycrystalline forward bounds for sea ice. The single crystal complex permittivity tensor is obtained by evaluating X-ray CT data of sea ice with known ice and brine permittivites and brine volume fraction using Comsol 3.5a. Further, inverse bounds are developed and the mean single crystal orientation can be bounded from measurements of the effective complex pe

  5. The Antarctic sea ice concentration budget of an ocean-sea ice coupled model

    NASA Astrophysics Data System (ADS)

    Lecomte, Olivier; Goosse, Hugues; Fichefet, Thierry; Holland, Paul R.; Uotila, Petteri

    2015-04-01

    The Antarctic sea ice concentration budget of the NEMO-LIM ocean-sea ice coupled model is computed and analyzed. Following a previously developed method, the sea ice concentration balance over the autumn-winter seasons is decomposed into four terms, including the sea ice concentration change during the period of interest, advection, divergence and a residual accounting for the net contribution of thermodynamics and ice deformation. Preliminary results from this analysis show that the geographical patterns of all budget terms over 1992-2010 are in qualitative agreement with the observed ones. Sea ice thermodynamic growth is maintained by horizontal divergence near the continent and in the central ice pack, while melting close to the ice edge is led by sea ice advection. Quantitatively however, the inner ice pack divergence and associated sea ice freezing are much stronger, as compared to observations. The advection of sea ice in both the central pack and the marginal areas are likewise stronger, which corroborates the findings of a previous study in which the same methods were applied to a fully coupled climate model. Nonetheless, the seasonal evolution of sea ice area and total extent are reasonably well simulated, since enhanced sea ice freezing due to larger divergence in the central pack is compensated by intensified melting in the outer pack owing to faster advection. Those strong dynamic components in the sea ice concentration budget are due to ice velocities that tend to be biased high all around Antarctica and particularly near the ice edge. The obtained results show that the applied method is particularly well suited for assessing the skills of an ocean-sea ice coupled model in simulating the seasonal and regional evolution of Antarctic sea ice for the proper physical reasons.

  6. Putting SEA in context: A discourse perspective on how SEA contributes to decision-making

    SciTech Connect

    Runhaar, Hens

    2009-04-15

    Over the last couple of years there is an ongoing debate in the environmental assessment literature about the contribution of Strategic Environmental Assessment (SEA) to public decision-making and how this can be understood and enhanced by better incorporating insights from policy analysis, planning theory and political sciences. By explicitly framing SEA as an element in a process where stakeholders with diverging interests struggle, acceptability of SEA processes and results by stakeholders has become an important element in SEA evaluation. In addition, the importance of other context variables, such as the institutional organisation, and the need for SEA to adapt to this context, is stressed. Thus far, publications in this area have been dealing with the operationalisation of SEA's 'contribution', typologies of roles that SEA can or should play in different policy settings and on factors that stimulate or impede SEA to play these roles. In this paper an alternative approach is suggested that starts from the deliberative processes around a particular policy issue or decision supported by SEA. Of particular interest are 'discourses': the frames through which groups of actors give meaning to aspects of the policy issues and decisions that are supported by SEA. Discourses do not only reflect conflicts of interests and power play, but also the ways in which actors perceive and understand aspects of the world. Decision-making is conceptualised as a 'system of competing discourse coalitions and their struggles to 'control shared meanings' and to gain acceptance of their framing of a policy issue' [Durning D. A review of Fischer and Forrester (1993) The argumentative turn in policy analysis and planning. Policy Sci 1995;28(1):102-8]. SEA is one of the events in this process that may impact upon dominant discourses. Discourse analysis allows for an understanding of arguments that are considered legitimate for (not) incorporating particular elements of SEA. In addition it opens the door to relatively new strategies for SEA professionals to enhance their contribution to decision-making.

  7. North-Australian tropical seas circulation study

    NASA Technical Reports Server (NTRS)

    Burrage, Derek; Coleman, R.; Bode, L.; Inoue, M.

    1991-01-01

    This investigation is intended to fully address the stated objective of the TOPEX/POSEIDON mission (National Aeronautics and Space Administration, 1986). Hence, we intend to use TOPEX/POSEIDON altimetry data to study the large-scale circulation of the Coral Sea Basin and the Arafura Sea and the mass exchange between these and adjoining basins. We will obtain data from two such cruises in 1993 and 1994 and combine them with TOPEX/POSEIDON radar altimetry data to identify interannual and seasonal changes in: (1) the location of the major ocean currents and the South Equatorial Current bifurcation in the Coral Sea; (2) the source region of the South Tropical Counter Current (STCC); and (3) the water exchange between the Coral Sea and the adjoining seas. We will also estimate seasonal and interannual variations in the horizontal transport of mass and heat associated with near-surface geostrophic and wind-driven currents. In addition, the tidal components of the Coral Sea will be studied to provide a correction for altimetry subtidal sea level changes and to develop a regional numerical model for tidal forcing in the Great Barrier Reef (GBR) and Papua New Guinea Reef regions.

  8. Low Frequency Variations of Relative Sea Level

    NASA Astrophysics Data System (ADS)

    Douglas, B. C.; Miller, L.

    2006-12-01

    Tide gauge records of sea level display variability at all frequencies, including centennial. This variability adversely impacts estimates of sea level rise, especially for records shorter than 50-75 years. Variability of sea level at tide gauge locations on the eastern boundaries of the N. Atlantic and N. Pacific oceans is very significant even for periods > 100 years. The longest records in the N. Atlantic (Brest) and N. Pacific (San Francisco), universally used in estimates of global sea level rise, display very different behavior in the latter half of the 19th century compared to the 20th century. We show that this behavior is closely related to, but not explained by, local sea level pressure at these sites. It is possible that the disparate behavior of sea level between the 19th and 20th centuries is related to ocean basin-scale atmospheric forcing. Examination of other long records in the northern and southern hemispheres reveals in many cases a leveling off of sea level after about 1960.

  9. Decadal stability of Red Sea mangroves

    NASA Astrophysics Data System (ADS)

    Almahasheer, Hanan; Aljowair, Abdulaziz; Duarte, Carlos M.; Irigoien, Xabier

    2016-02-01

    Across the Earth, mangroves play an important role in coastal protection, both as nurseries and carbon sinks. However, due to various human and environmental impacts, the coverage of mangroves is declining on a global scale. The Red Sea is in the northern-most area of the distribution range of mangroves. Little is known about the surface covered by mangroves at this northern limit or about the changes experienced by Red Sea mangroves. We sought to study changes in the coverage of Red Sea mangroves by using multi-temporal Landsat data (1972, 2000 and 2013). Interestingly, our results show that there has been no decline in mangrove stands in the Red Sea but rather a slight increase. The area covered by mangroves is about 69 Km2 along the African shore and 51 Km2 along the Arabian Peninsula shore. From 1972 to 2013, the area covered by mangroves increased by about 0.29% y-1. We conclude that the trend exhibited by Red Sea mangroves departs from the general global decline of mangroves. Along the Red Sea, mangroves expanded by 12% over the 41 years from 1972 to 2013. Losses to Red Sea mangroves, mostly due to coastal development, have been compensated by afforestation projects.

  10. Dissolved organic matter in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Hoikkala, L.; Kortelainen, P.; Soinne, H.; Kuosa, H.

    2015-02-01

    Several factors highlight the importance of dissolved organic matter (DOM) in coastal ecosystems such as the Baltic Sea: 1) DOM is the main energy source for heterotrophic bacteria in surface waters, thus contributing to the productivity and trophic state of bodies of water. 2) DOM functions as a nutrient source: in the Baltic Sea, more than one-fourth of the bioavailable nutrients can occur in the dissolved organic form in riverine inputs and in surface water during summer. Thus, DOM also supports primary production, both directly (osmotrophy) and indirectly (via remineralization). 3) Flocculation and subsequent deposition of terrestrial DOM within river estuaries may contribute to production and oxygen consumption in coastal sediments. 4) Chromophoric DOM, which is one of the major absorbers of light entering the Baltic Sea, contributes highly to water color, thus affecting the photosynthetic depth as well as recreational value of the Baltic Sea. Despite its large-scale importance to the Baltic Sea ecosystem, DOM has been of minor interest compared with inorganic nutrient loadings. Information on the concentrations and dynamics of DOM in the Baltic Sea has accumulated since the late 1990s, but it is still sporadic. This review provides a coherent view of the current understanding of DOM dynamics in the Baltic Sea.

  11. Recent changes in Antarctic Sea Ice.

    PubMed

    Turner, John; Hosking, J Scott; Bracegirdle, Thomas J; Marshall, Gareth J; Phillips, Tony

    2015-07-13

    In contrast to the Arctic, total sea ice extent (SIE) across the Southern Ocean has increased since the late 1970s, with the annual mean increasing at a rate of 186×10(3) km(2) per decade (1.5% per decade; p<0.01) for 1979-2013. However, this overall increase masks larger regional variations, most notably an increase (decrease) over the Ross (Amundsen-Bellingshausen) Sea. Sea ice variability results from changes in atmospheric and oceanic conditions, although the former is thought to be more significant, since there is a high correlation between anomalies in the ice concentration and the near-surface wind field. The Southern Ocean SIE trend is dominated by the increase in the Ross Sea sector, where the SIE is significantly correlated with the depth of the Amundsen Sea Low (ASL), which has deepened since 1979. The depth of the ASL is influenced by a number of external factors, including tropical sea surface temperatures, but the low also has a large locally driven intrinsic variability, suggesting that SIE in these areas is especially variable. Many of the current generation of coupled climate models have difficulty in simulating sea ice. However, output from the better-performing IPCC CMIP5 models suggests that the recent increase in Antarctic SIE may be within the bounds of intrinsic/internal variability. PMID:26032320

  12. Influence of sea ice on Arctic precipitation.

    PubMed

    Kopec, Ben G; Feng, Xiahong; Michel, Fred A; Posmentier, Eric S

    2016-01-01

    Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on the Arctic hydrologic cycle, such as the strength of meridional transport, are assessed using the North Atlantic Oscillation index. We find that the independent, direct effect of sea ice on the increase of the percentage of Arctic sourced moisture (or Arctic moisture proportion, AMP) is 18.2 ± 4.6% and 10.8 ± 3.6%/100,000 km(2) sea ice lost for each region, respectively, corresponding to increases of 10.9 ± 2.8% and 2.7 ± 1.1%/1 °C of warming in the vapor source regions. The moisture source changes likely result in increases of precipitation and changes in energy balance, creating significant uncertainty for climate predictions. PMID:26699509

  13. Sea-ice thermodynamics and brine drainage.

    PubMed

    Worster, M Grae; Rees Jones, David W

    2015-07-13

    Significant changes in the state of the Arctic ice cover are occurring. As the summertime extent of sea ice diminishes, the Arctic is increasingly characterized by first-year rather than multi-year ice. It is during the early stages of ice growth that most brine is injected into the oceans, contributing to the buoyancy flux that mediates the thermo-haline circulation. Current operational sea-ice components of climate models often treat brine rejection between sea ice and the ocean similarly to a thermodynamic segregation process, assigning a fixed salinity to the sea ice, typical of multi-year ice. However, brine rejection is a dynamical, buoyancy-driven process and the salinity of sea ice varies significantly during the first growth season. As a result, current operational models may over predict the early brine fluxes from newly formed sea ice, which may have consequences for coupled simulations of the polar oceans. Improvements both in computational power and our understanding of the processes involved have led to the emergence of a new class of sea-ice models that treat brine rejection dynamically and should enhance predictions of the buoyancy forcing of the oceans. PMID:26032321

  14. Severe Storm in the Sea of Azov

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A fierce storm struck both the Black Sea and the Sea of Azov on November 11, 2007. According to news reports, as many as 10 ships either sank or ran aground, one of them an oil tanker. The Russian tanker Volganeft-139 was anchored to the sea floor in the Kerch Strait linking the Black and Azov Seas when 108-kilometer- (67-mile-) per-hour winds tore the ship apart. As of November 12, up to 2,000 metric tons of fuel oil had leaked from the ship. On November 11, 2007, the day the storm struck, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image of the region. Thick clouds obscure the view of much of the land area, including Ukraine, Belarus, western Russia, and Georgia. Clouds also obscure the Sea of Azov, although skies over the Black Sea are somewhat clearer. Over the Sea of Azov and immediately to the north, the clouds form a vague swirling pattern, suggestive of a low-pressure cyclonic system.

  15. New Coccolithophore Bloom in Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    For the fourth year in a row it appears as if there is a bloom of coccolithophores-marine single-celled plants with calcite scales-in the Bering Sea off the coast of Alaska. Similar blooms were rare before 1997, but they have appeared every year since then. Scientists believe the coccolithophore blooms are the result of changing wind patterns in the region. Weaker than normal winds fail to mix the water of the Bering Sea, resulting in the growth of coccolithophores instead of other types of phytoplankton. Seabird populations have also been changing as a result of this climate change. The Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, saw the coccolith-brightened waters of the Bering Sea in 1997, 1998, and 1999. The waters have looked fairly bright again this winter and spring, as seen in this SeaWiFS image acquired April 29, 2000. But scientists are unsure whether this year's phenomenon is caused by living coccolithophorids, re-suspended coccoliths, or something else. Like all phytoplankton, coccolithophores contain chlorophyll and have the tendency to multiply rapidly near the surface. Yet, in large numbers, coccolithophores periodically shed their tiny scales, called 'coccoliths,' by the bucketful into the surrounding waters. The calcium-rich coccoliths turn the normally dark water a bright, milky aquamarine, making coccolithophore blooms easy to spot in satellite imagery. The edge of the whitish cloud in the water seen in this image is roughly 50 kilometers off the West Coast of Alaska. For more information see: SeaWiFS home page Changing Currents Color the Bering Sea a New Shade of Blue Image courtesy SeaWiFS project

  16. Sea level changes: observations versus models

    NASA Astrophysics Data System (ADS)

    Mörner, N.-A.

    2003-04-01

    Sea level rose for glacial eustatic reasons up to about 5000 BP. After that, global sea level has been dominated by the redistribution of ocean water masses (and by that ocean-stored heat). This redistribution of water masses is driven by the interchange of angular momentum between the solid earth and the hydrosphere (in feedback coupling) primarily expressed as changes in the oceanic surface current systems. In view of this, there has been very hard to define any global eustatic signal. This is where and why a dialectic between models and observations enter the sea level debate. According to the glacial loading models, global sea level is now rising by 2.4 mm/year or 1.8 mm/year. The IPCC models have hypothesised of a very rapid rise in the near future, ranging for original wild estimates of 1-3 m in a century to the presently advocated value of 47 +37 mm in a century. The INQUA Commission on Sea Level Changes and Coastal Evolution (www.pog.su.se/sea) hosts the true world specialists on sea level research. This commission has presented an observationally based analysis of the present sea level changes and the changes to be expected in the next century. Both the glacial loading models and the ICPP scenarios are strongly contradicted by observational data for the last 100-150 years that cannot have exceeded a mean rate of 1.0-1.1 mm/year. In the last 300 years, sea level has been oscillation close to the present with peak rates in the period 1890-1930. Sea level fell between 1930 and 1950. The late 20th century lacks any sign of acceleration. Satellite altimetry indicates virtually no changes in the last decade. Therefore, observationally based predictions of future sea level in the year 2100 will give a value of +10 +10 cm (or +5 +15 cm), by this discarding model out-puts by IPCC as well as global loading models. On a regional scale, the Maldives research project has revealed that there are absolutely no signs what so ever on any on-going flooding of the Maldives. On the contrary, a distinct sea level fall is recorded at ~1970. In conclusions, there are firm observationally based reasons to free the world from the condemnation to become extensively flooded in the 21st century AD.

  17. District cooling in Stockholm using sea water

    SciTech Connect

    Fermbaeck, G.

    1995-12-31

    In May this year Stockholm Energi started supplying properties in central Stockholm with cooling for comfort and for various processes from its new district cooling system. The project is unique in that most of the cooling energy is produced using cold water from the Baltic Sea. The following article describes the system and provides a summary of the considerations that resulted in venturing to invest in sea-water cooling for such a large project. There is also a description of the hydrological conditions that made the system feasible in Stockholm and some speculations about the possibilities to use cooled sea water elsewhere in the world.

  18. Common Era Sea-Level Change

    NASA Astrophysics Data System (ADS)

    Horton, B.; Kemp, A.; Kopp, R. E., III

    2014-12-01

    The Atlantic coast of North America provides a sedimentary record of Common Era sea levels with the resolution to identify the mechanisms that cause spatial variability in sea-level rise. This coast has a small tidal range, improving the precision of sea-level reconstructions. Coastal subsidence (from glacial isostatic adjustment, GIA) creates accommodation space that is filled by salt-marsh peat and preserves accurate and precise sea-level indicators and abundant material for radiocarbon dating. In addition, the western North Atlantic Ocean is sensitive to spatial variability in sea-level change, because of static equilibrium effects from melting of the Greenland Ice Sheet, ocean circulation and wind-driven variability in the Gulf Stream and GIA induced land-level change from ongoing collapse of Laurentide forbuldge. We reveal three distinct patters in sea-level during the Common Era along the North American Atlantic coast, likely linked to wind-driven changes in the Gulf Stream: (1) Florida, sea level is essentially flat, with the record dominated by long-term geological processes; (2) North Carolina, sea level falls to a minimum near the beginning of the second millennium, climbing to an early Little Ice Age maximum in the fifteenth century, and then declining through most of the nineteenth century; and (3) New Jersey, a sea-level maximum around 900 CE, a sea-level minimum around 1500 CE, and a long-term sea-level rise through the second half of the second millennium. We combine the salt-marsh data from North American Atlantic coast with tide-gauge records and lower resolution proxies from the northern and southern hemispheres. We apply a noisy-input Gaussian process spatio-temporal modeling framework, which identifies a long-term falling global mean sea-level (GMSL), interrupted in the middle of the 19th century by an acceleration yielding a 20th century rate of rise extremely likely (probability P = 0:95) faster than any previous century in the Common Era.

  19. Pulsations, interpulsations, and sea-floor spreading.

    NASA Technical Reports Server (NTRS)

    Pessagno, E. A., Jr.

    1973-01-01

    It is postulated that worldwide transgressions (pulsations) and regressions (interpulsations) through the course of geologic time are related to the elevation and subsidence of oceanic ridge systems and to sea-floor spreading. Two multiple working hypotheses are advanced to explain major transgressions and regressions and the elevation and subsidence of oceanic ridge systems. One hypothesis interrelates the sea-floor spreading hypothesis to the hypothesis of sub-Mohorovicic serpentinization. The second hypothesis relates the sea-floor spreading hypothesis to a hypothesis involving thermal expansion and contraction.

  20. What Can Sea Ice Reconstructions Tell Us About Recent Regional Trends in Sea Ice Around Antarctica?

    NASA Astrophysics Data System (ADS)

    Abram, N.; Mulvaney, R.; Murphy, E. J.

    2014-12-01

    Satellite observations of recent sea ice changes around Antarctica reveal regionally heterogeneous trends, but with an overall increasing trend in Antarctic-wide sea ice extent. Proposed mechanisms to account for increasing sea ice extent around Antarctica include freshening of the ocean surface due to melting of land ice and northward wind drift associated with strengthening of the Southern Ocean westerly winds. In this study we use extended, regional reconstructions of Antarctic sea ice changes from ice core chemistry and reanalysis of the South Orkney fast ice series to examine long-term relationships between Antarctic regional sea ice changes and surface winds. The formation and breakout of fast ice at the South Orkney islands (Murphy et al., 2014) indicates that westerly wind strength is an important factor in determining spring sea ice retreat in the Weddell Sea region. In contrast, autumn sea ice formation is more strongly influenced by long-lived ocean temperature anomalies and sea ice migration from the previous year, highlighting the multiple influences that act at different times of the year to determine the overall extent of winter sea ice. To assess the hypothesized role of westerly wind changes in driving opposing patterns of recent sea ice change between the Ross Sea and Bellingshausen Sea, we also present a comparison of ice core MSA evidence for sea ice changes derived from the James Ross Island (Mulvaney et al., 2012) and Erebus Saddle (Rhodes et al., 2012) ice cores, and view this in the context of trends in the Southern Annular Mode (Abram et al., 2014) over the last 200 years. References: Abram et al., 2014. Evolution of the Southern Annular Mode over the past millennium. Nature Climate Change. doi: 10.1038/nclimate2235 Mulvaney et al., 2012. Recent Antarctic Peninsula warming relative to Holocene temperature and ice-shelf history. Nature. doi: 10.1038/nature11391 Murphy et al., 2014. Variability of sea ice in the northern Weddell Sea during the 20th century. Journal of Geophysical Research. doi: 10.1002/2013JC009511 Rhodes et al., 2012. Little Ice Age climate and oceanic conditions of the Ross Sea, Antarctica, from a coastal ice core record. Climate of the Past. doi: 10.5194/cp-8-1223-2012

  1. Does Arctic sea ice reduction foster shelf-basin exchange?

    PubMed

    Ivanov, Vladimir; Watanabe, Eiji

    2013-12-01

    The recent shift in Arctic ice conditions from prevailing multi-year ice to first-year ice will presumably intensify fall-winter sea ice freezing and the associated salt flux to the underlying water column. Here, we conduct a dual modeling study whose results suggest that the predicted catastrophic consequences for the global thermohaline circulation (THC), as a result of the disappearance of Arctic sea ice, may not necessarily occur. In a warmer climate, the substantial fraction of dense water feeding the Greenland-Scotland overflow may form on Arctic shelves and cascade to the deep basin, thus replenishing dense water, which currently forms through open ocean convection in the sub-Arctic seas. We have used a simplified model for estimating how increased ice production influences shelf-basin exchange associated with dense water cascading. We have carried out case studies in two regions of the Arctic Ocean where cascading was observed in the past. The baseline range of buoyancy-forcing derived from the columnar ice formation was calculated as part of a 30-year experiment of the pan-Arctic coupled ice-ocean general circulation model (GCM). The GCM results indicate that mechanical sea ice divergence associated with lateral advection accounts for a significant part of the interannual variations in sea ice thermal production in the coastal polynya regions. This forcing was then rectified by taking into account sub-grid processes and used in a regional model with analytically prescribed bottom topography and vertical stratification in order to examine specific cascading conditions in the Pacific and Atlantic sectors of the Arctic Ocean. Our results demonstrate that the consequences of enhanced ice formation depend on geographical location and shelf-basin bathymetry. In the Pacific sector, strong density stratification in slope waters impedes noticeable deepening of shelf-origin water, even for the strongest forcing applied. In the Atlantic sector, a 1.5x increase of salt flux leads to a threefold increase of shelf-slope volume flux below the warm core of Atlantic water. This threefold increase would be a sufficient substitute for a similar amount of dense water that currently forms in the Greenland, Iceland, and Norwegian (GIN) seas but is expected to decrease in a warming climate. PMID:24555308

  2. Surface-based passive microwave observations of sea ice in the Bering and Greenland Seas

    NASA Technical Reports Server (NTRS)

    Grenfell, T. C.

    1986-01-01

    Brightness temperatures of sea ice was measured during the Marginal Ice Zone Experiment (MIZEX) field experiments in February in the Bering Sea and in June/July in the northern Greenland Sea. In the Bering Sea thin growing sea ice types from black ice to 40 cm thick snow covered floes were investigated. Brightness temperatures increase with ice thickness up to 10 cm from values of 100 K for open water to as high as 250 K (e = 0.97) for thick ice, and a moderate dependence on snow thickness is found. In the Greenland Sea thick first and multiyear (FY, MY) ice types were studied. Brightness temperatures vary, depending on the daily melt-freeze cycle superimposed on the seasonal warming, ranging from near blackbody values for melting conditions to multiyear-like spectra when the surface layers refroze. The melt season was sufficiently advanced, however, that FY and MY ice could not be differentiated radiometrically.

  3. Effects of Mackenzie River Discharge and Bathymetry on Sea Ice in the Beaufort Sea

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Hall, D. K.; Rigor, I. G; Li, P.; Neumann, G.

    2014-01-01

    Mackenzie River discharge and bathymetry effects on sea ice in the Beaufort Sea are examined in 2012 when Arctic sea ice extent hit a record low. Satellite-derived sea surface temperature revealed warmer waters closer to river mouths. By 5 July 2012, Mackenzie warm waters occupied most of an open water area about 316,000 sq km. Surface temperature in a common open water area increased by 6.5 C between 14 June and 5 July 2012, before and after the river waters broke through a recurrent landfast ice barrier formed over the shallow seafloor offshore the Mackenzie Delta. In 2012, melting by warm river waters was especially effective when the strong Beaufort Gyre fragmented sea ice into unconsolidated floes. The Mackenzie and other large rivers can transport an enormous amount of heat across immense continental watersheds into the Arctic Ocean, constituting a stark contrast to the Antarctic that has no such rivers to affect sea ice.

  4. Coccoliths in the Celtic Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    As the basis of the marine food chain, phytoplankton are important indicators of change in the oceans. These marine flora also extract carbon dioxide from the atmosphere for use in photosynthesis, and play an important role in global climate. Phytoplankton blooms that occur near the surface are readily visible from space, enabling a global estimation of the presence of chlorophyll and other pigments. There are more than 5,000 different species of phytoplankton however, and it is not always possible to identify the type of phytoplankton present using space-based remote sensing.

    Coccolithophores, however, are a group of phytoplankton that are identifiable from space. These microscopic plants armor themselves with external plates of calcium carbonate. The plates, or coccoliths, give the ocean a milky white or turquoise appearance during intense blooms. The long-term flux of coccoliths to the ocean floor is the main process responsible for the formation of chalk and limestone.

    This image is a natural-color view of the Celtic Sea and English Channel regions, and was acquired by the Multi-angle Imaging SpectroRadiometer's nadir (vertical-viewing) camera on June 4, 2001 during Terra orbit 7778. It represents an area of 380 kilometers x 445 kilometers, and includes portions of southwestern England and northwestern France. The coccolithophore bloom in the lower left-hand corner usually occurs in the Celtic Sea for several weeks in summer. The coccoliths backscatter light from the water column to create a bright optical effect. Other algal and/or phytoplankton blooms can also be discerned along the coasts near Portsmouth, England and Granville, France.

    At full resolution, evidence of human activity is also apparent in this image. White specks associated with ship wakes are present in the open water, and aircraft contrails are visible within the high cirrus clouds over the English Channel.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  5. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions

    PubMed Central

    Rode, Karyn D.; Wilson, Ryan R.; Regehr, Eric V.; St. Martin, Michelle; Douglas, David C.; Olson, Jay

    2015-01-01

    Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986–1995 and 2008–2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions. PMID:26580809

  6. Sea-level variability in the Mediterranean Sea from altimetry and tide gauges

    NASA Astrophysics Data System (ADS)

    Bonaduce, A.; Pinardi, N.; Oddo, P.; Spada, G.; Larnicol, G.

    2016-02-01

    Sea-level variability in the Mediterranean Sea was investigated by means of in-situ (tide-gauge) and satellite altimetry data over a period spanning two decades (from 1993 to 2012). The paper details the sea-level variations during this time period retrieved from the two data sets. Mean sea-level (MSL) estimates obtained from tide-gauge data showed root mean square differences (RMSDs) in the order of 40-50 % of the variance of the MSL signal estimated from satellite altimetry data, with a dependency on the number and quality of the in-situ data considered. Considering the individual time-series, the results showed that coastal tide-gauge and satellite sea-level signals are comparable, with RMSDs that range between 2.5 and 5 cm and correlation coefficients up to the order of 0.8. A coherence analysis and power spectra comparison showed that two signals have a very similar energetic content at semi-annual temporal scales and below, while a phase drift was observed at higher frequencies. Positive sea-level linear trends for the analysis period were estimated for both the mean sea-level and the coastal stations. From 1993 to 2012, the mean sea-level trend (2.44± 0.5 mm year^{-1} ) was found to be affected by the positive anomalies of 2010 and 2011, which were observed in all the cases analysed and were mainly distributed in the eastern part of the basin. Ensemble empirical mode decomposition showed that these events were related to the processes that have dominant periodicities of ˜ 10 years, and positive residual sea-level trend were generally observed in both data-sets. In terms of mean sea-level trends, a significant positive sea-level trend (> 95 %) in the Mediterranean Sea was found on the basis of at least 15 years of data.

  7. Increased land use by Chukchi Sea polar bears in relation to changing sea ice conditions

    USGS Publications Warehouse

    Rode, Karyn D.; Wilson, Ryan R.; Regehr, Eric V.; St. Martin, Michelle; Douglas, David; Olson, Jay

    2015-01-01

    Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986–1995 and 2008–2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.

  8. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions.

    PubMed

    Rode, Karyn D; Wilson, Ryan R; Regehr, Eric V; St Martin, Michelle; Douglas, David C; Olson, Jay

    2015-01-01

    Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions. PMID:26580809

  9. Walrus areas of use in the Chukchi Sea during sparse sea ice cover

    USGS Publications Warehouse

    Jay, Chadwick V.; Fischbach, Anthony S.; Kochnev, Anatoly A.

    2012-01-01

    The Pacific walrus Odobenus rosmarus divergens feeds on benthic invertebrates on the continental shelf of the Chukchi and Bering Seas and rests on sea ice between foraging trips. With climate warming, ice-free periods in the Chukchi Sea have increased and are projected to increase further in frequency and duration. We radio-tracked walruses to estimate areas of walrus foraging and occupancy in the Chukchi Sea from June to November of 2008 to 2011, years when sea ice was sparse over the continental shelf in comparison to historical records. The earlier and more extensive sea ice retreat in June to September, and delayed freeze-up of sea ice in October to November, created conditions for walruses to arrive earlier and stay later in the Chukchi Sea than in the past. The lack of sea ice over the continental shelf from September to October caused walruses to forage in nearshore areas instead of offshore areas as in the past. Walruses did not frequent the deep waters of the Arctic Basin when sea ice retreated off the shelf. Walruses foraged in most areas they occupied, and areas of concentrated foraging generally corresponded to regions of high benthic biomass, such as in the northeastern (Hanna Shoal) and southwestern Chukchi Sea. A notable exception was the occurrence of concentrated foraging in a nearshore area of northwestern Alaska that is apparently depauperate in walrus prey. With increasing sea ice loss, it is likely that walruses will increase their use of coastal haul-outs and nearshore foraging areas, with consequences to the population that are yet to be understood.

  10. 50 CFR 648.145 - Black sea bass possession limit.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Black sea bass possession limit. 648.145... Measures for the Black Sea Bass Fishery 648.145 Black sea bass possession limit. (a) From January 1 through February 28, no person shall possess more than 15 black sea bass in, or harvested from, the...

  11. 50 CFR 648.145 - Black sea bass possession limit.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Black sea bass possession limit. 648.145... Measures for the Black Sea Bass Fishery 648.145 Black sea bass possession limit. (a) During the recreational fishing season specified at 648.146, no person shall possess more than 15 black sea bass in,...

  12. 50 CFR 648.145 - Black sea bass possession limit.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Black sea bass possession limit. 648.145... Measures for the Black Sea Bass Fishery 648.145 Black sea bass possession limit. (a) During the recreational fishing season specified at 648.146, no person shall possess more than 20 black sea bass in,...

  13. 76 FR 16731 - National Sea Grant Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-25

    ... National Oceanic and Atmospheric Administration National Sea Grant Advisory Board AGENCY: National Oceanic... National Sea Grant Advisory Board members. SUMMARY: This notice responds to Section 209 of the Sea Grant... to solicit nominations at least once a year for membership on the National Sea Grant Advisory...

  14. 75 FR 13803 - SeaCo Ltd.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-23

    ... COMMISSION SeaCo Ltd.; Notice of Application March 17, 2010. AGENCY: Securities and Exchange Commission... (``Act''). SUMMARY: Summary of Application: SeaCo Ltd. (``SeaCo'') seeks an order under section 3(b)(2..., reinvesting, owning, holding or trading in securities. SeaCo is primarily engaged in the shipping...

  15. SIPEX--Exploring the Antarctic Sea Ice Zone

    ERIC Educational Resources Information Center

    Zicus, Sandra; Dobson, Jane; Worby, Anthony

    2008-01-01

    Sea ice in the polar regions plays a key role in both regulating global climate and maintaining marine ecosystems. The international Sea Ice Physics and Ecosystem eXperiment (SIPEX) explored the sea ice zone around Antarctica in September and October 2007, investigating relationships between the physical sea ice environment and the structure of

  16. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  17. 15 CFR 917.11 - Guidelines for Sea Grant Fellowships.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Guidelines for Sea Grant Fellowships... Sea Grant Fellowships. (a) Sea Grant Fellowships are designed to provide educational and training... applications for Sea Grant Fellowship funding. (b) Funding will be made to eligible entities (see § 917.10...

  18. 15 CFR 917.11 - Guidelines for Sea Grant Fellowships.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Guidelines for Sea Grant Fellowships... Sea Grant Fellowships. (a) Sea Grant Fellowships are designed to provide educational and training... applications for Sea Grant Fellowship funding. (b) Funding will be made to eligible entities (see § 917.10...

  19. 15 CFR 917.11 - Guidelines for Sea Grant Fellowships.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Guidelines for Sea Grant Fellowships... Sea Grant Fellowships. (a) Sea Grant Fellowships are designed to provide educational and training... applications for Sea Grant Fellowship funding. (b) Funding will be made to eligible entities (see § 917.10...

  20. 15 CFR 917.11 - Guidelines for Sea Grant Fellowships.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Guidelines for Sea Grant Fellowships... Sea Grant Fellowships. (a) Sea Grant Fellowships are designed to provide educational and training... applications for Sea Grant Fellowship funding. (b) Funding will be made to eligible entities (see § 917.10...

  1. 15 CFR 917.11 - Guidelines for Sea Grant Fellowships.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Guidelines for Sea Grant Fellowships... Sea Grant Fellowships. (a) Sea Grant Fellowships are designed to provide educational and training... applications for Sea Grant Fellowship funding. (b) Funding will be made to eligible entities (see § 917.10...

  2. 46 CFR 42.30-30 - Enclosed seas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: December 16 to March 15. Summer: March 16 to December 15. (d) Sea of Japan. This sea south of the parallel... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Zones... November 30. (c) Mediterranean. This sea is included in the Summer Zones. (1) However, for vessels of...

  3. 46 CFR 42.30-30 - Enclosed seas.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: December 16 to March 15. Summer: March 16 to December 15. (d) Sea of Japan. This sea south of the parallel... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Zones... November 30. (c) Mediterranean. This sea is included in the Summer Zones. (1) However, for vessels of...

  4. 46 CFR 42.30-30 - Enclosed seas.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: December 16 to March 15. Summer: March 16 to December 15. (d) Sea of Japan. This sea south of the parallel... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Zones... November 30. (c) Mediterranean. This sea is included in the Summer Zones. (1) However, for vessels of...

  5. The Secret of the Svalbard Sea Ice Barrier

    NASA Technical Reports Server (NTRS)

    Nghiem, Son V.; Van Woert, Michael L.; Neumann, Gregory

    2004-01-01

    An elongated sea ice feature called the Svalbard sea ice barrier rapidly formed over an area in the Barents Sea to the east of Svalbard posing navigation hazards. The secret of its formation lies in the bottom bathymetry that governs the distribution of cold Arctic waters masses, which impacts sea ice growth on the water surface.

  6. SIPEX--Exploring the Antarctic Sea Ice Zone

    ERIC Educational Resources Information Center

    Zicus, Sandra; Dobson, Jane; Worby, Anthony

    2008-01-01

    Sea ice in the polar regions plays a key role in both regulating global climate and maintaining marine ecosystems. The international Sea Ice Physics and Ecosystem eXperiment (SIPEX) explored the sea ice zone around Antarctica in September and October 2007, investigating relationships between the physical sea ice environment and the structure of…

  7. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  8. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  9. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  10. 34 CFR 300.149 - SEA responsibility for general supervision.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false SEA responsibility for general supervision. 300.149... EDUCATION OF CHILDREN WITH DISABILITIES State Eligibility Sea Responsibility for General Supervision and Implementation of Procedural Safeguards 300.149 SEA responsibility for general supervision. (a) The SEA...

  11. 34 CFR 300.146 - Responsibility of SEA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true Responsibility of SEA. 300.146 Section 300.146 Education... Agencies 300.146 Responsibility of SEA. Each SEA must ensure that a child with a disability who is placed... apply to education provided by the SEA and LEAs including the requirements of this part, except...

  12. 34 CFR 300.150 - SEA implementation of procedural safeguards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false SEA implementation of procedural safeguards. 300.150... EDUCATION OF CHILDREN WITH DISABILITIES State Eligibility Sea Responsibility for General Supervision and Implementation of Procedural Safeguards 300.150 SEA implementation of procedural safeguards. The SEA (and...

  13. 34 CFR 300.146 - Responsibility of SEA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Responsibility of SEA. 300.146 Section 300.146 Education... Agencies 300.146 Responsibility of SEA. Each SEA must ensure that a child with a disability who is placed... apply to education provided by the SEA and LEAs including the requirements of this part, except...

  14. 50 CFR 648.59 - Sea Scallop Access Areas.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Sea Scallop Access Areas. 648.59 Section... Atlantic Sea Scallop Fishery 648.59 Sea Scallop Access Areas. (a) (b) Closed Area I Access Area(1) From..., or land scallops in or from the area known as the Closed Area II Sea Scallop Access Area,...

  15. 34 CFR 300.211 - Information for SEA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true Information for SEA. 300.211 Section 300.211 Education... DISABILITIES Local Educational Agency Eligibility 300.211 Information for SEA. The LEA must provide the SEA with information necessary to enable the SEA to carry out its duties under Part B of the Act,...

  16. 34 CFR 300.146 - Responsibility of SEA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false Responsibility of SEA. 300.146 Section 300.146... Referred by Public Agencies 300.146 Responsibility of SEA. Each SEA must ensure that a child with a... the standards that apply to education provided by the SEA and LEAs including the requirements of...

  17. 33 CFR 2.20 - Territorial sea baseline.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Territorial sea baseline. 2.20... JURISDICTION Jurisdictional Terms 2.20 Territorial sea baseline. Territorial sea baseline means the line defining the shoreward extent of the territorial sea of the United States drawn according to the...

  18. 33 CFR 2.20 - Territorial sea baseline.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Territorial sea baseline. 2.20... JURISDICTION Jurisdictional Terms 2.20 Territorial sea baseline. Territorial sea baseline means the line defining the shoreward extent of the territorial sea of the United States drawn according to the...

  19. 34 CFR 300.150 - SEA implementation of procedural safeguards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true SEA implementation of procedural safeguards. 300.150... EDUCATION OF CHILDREN WITH DISABILITIES State Eligibility Sea Responsibility for General Supervision and Implementation of Procedural Safeguards 300.150 SEA implementation of procedural safeguards. The SEA (and...

  20. 33 CFR 2.20 - Territorial sea baseline.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Territorial sea baseline. 2.20... JURISDICTION Jurisdictional Terms 2.20 Territorial sea baseline. Territorial sea baseline means the line defining the shoreward extent of the territorial sea of the United States drawn according to the...