Geological and Structural evolution of the Eurasia Africa plate boundary in the Gulf of Cadiz Central Eastern Atlantic Sea.

OpenAIRE

D’Oriano, Filippo

2010-01-01

Iberia Africa plate boundary, cross, roughly W-E, connecting the eastern Atlantic Ocean from Azores triple junction to the Continental margin of Morocco. Relative movement between the two plate change along the boundary, from transtensive near the Azores archipelago, through trascurrent movement in the middle at the Gloria Fracture Zone, to transpressive in the Gulf of Cadiz area. This study presents the results of geophysical and geological analysis on the plate boundary area offshore Gibral...

The Pelagics Habitat Analysis Module (PHAM): Decision Support Tools for Pelagic Fisheries

Science.gov (United States)

Armstrong, E. M.; Harrison, D. P.; Kiefer, D.; O'Brien, F.; Hinton, M.; Kohin, S.; Snyder, S.

2009-12-01

PHAM is a project funded by NASA to integrate satellite imagery and circulation models into the management of commercial and threatened pelagic species. Specifically, the project merges data from fishery surveys, and fisheries catch and effort data with satellite imagery and circulation models to define the habitat of each species. This new information on habitat will then be used to inform population distribution and models of population dynamics that are used for management. During the first year of the project, we created two prototype modules. One module, which was developed for the Inter-American Tropical Tuna Commission, is designed to help improve information available to manage the tuna fisheries of the eastern Pacific Ocean. The other module, which was developed for the Coastal Pelagics Division of the Southwest Fishery Science Center, assists management of by-catch of mako, blue, and thresher sharks along the Californian coast. Both modules were built with the EASy marine geographic information system, which provides a 4 dimensional (latitude, longitude, depth, and time) home for integration of the data. The projects currently provide tools for automated downloading and geo-referencing of satellite imagery of sea surface temperature, height, and chlorophyll concentrations; output from JPL’s ECCO2 global circulation model and its ROM California current model; and gridded data from fisheries and fishery surveys. It also provides statistical tools for defining species habitat from these and other types of environmental data. These tools include unbalanced ANOVA, EOF analysis of satellite imagery, and multivariate search routines for fitting fishery data to transforms of the environmental data. Output from the projects consists of dynamic maps of the distribution of the species that are driven by the time series of satellite imagery and output from the circulation models. It also includes relationships between environmental variables and recruitment. During

Pelagic Project Mauritania 2005-2006

NARCIS (Netherlands)

Heessen, H.J.L.; Tjoe-Awie, P.J.; Haan, de D.; Ybema, M.S.

2007-01-01

The Pelagic Project Mauritania 2005-2006 was the continuation of two earlier, but similar, projects for the years 1998-2001 and 2002-2004. The project was carried out in cooperation between IMARES and IMROP and had as most important objectives to further the assessment of small pelagic species,

Modeled distribution and abundance of a pelagic seabird reveal trends in relation to fisheries

Science.gov (United States)

Renner, Martin; Parrish, Julia K.; Piatt, John F.; Kuletz, Kathy J.; Edwards, Ann E.; Hunt, George L.

2013-01-01

The northern fulmar Fulmarus glacialis is one of the most visible and widespread seabirds in the eastern Bering Sea and Aleutian Islands. However, relatively little is known about its abundance, trends, or the factors that shape its distribution. We used a long-term pelagic dataset to model changes in fulmar at-sea distribution and abundance since the mid-1970s. We used an ensemble model, based on a weighted average of generalized additive model (GAM), multivariate adaptive regression splines (MARS), and random forest models to estimate the pelagic distribution and density of fulmars in the waters of the Aleutian Archipelago and Bering Sea. The most important predictor variables were colony effect, sea surface temperature, distribution of fisheries, location, and primary productivity. We calculated a time series from the ratio of observed to predicted values and found that fulmar at-sea abundance declined from the 1970s to the 2000s at a rate of 0.83% (± 0.39% SE) per annum. Interpolating fulmar densities on a spatial grid through time, we found that the center of fulmar distribution in the Bering Sea has shifted north, coinciding with a northward shift in fish catches and a warming ocean. Our study shows that fisheries are an important, but not the only factor, shaping fulmar distribution and abundance trends in the eastern Bering Sea and Aleutian Islands.

Influence of variable rates of neritic carbonate deposition on atmospheric carbon dioxide and pelagic sediments

Science.gov (United States)

Walker, J. C.; Opdyke, B. C.

1995-01-01

Short-term imbalances in the global cycle of shallow water calcium carbonate deposition and dissolution may be responsible for much of the observed Pleistocene change in atmospheric carbon dioxide content. However, any proposed changes in the alkalinity balance of the ocean must be reconciled with the sedimentary record of deep-sea carbonates. The possible magnitude of the effect of shallow water carbonate deposition on the dissolution of pelagic carbonate can be tested using numerical simulations of the global carbon cycle. Boundary conditions can be defined by using extant shallow water carbonate accumulation data and pelagic carbonate deposition/dissolution data. On timescales of thousands of years carbonate deposition versus dissolution is rarely out of equilibrium by more than 1.5 x 10(13) mole yr-1. Results indicate that the carbonate chemistry of the ocean is rarely at equilibrium on timescales less than 10 ka. This disequilibrium is probably due to sea level-induced changes in shallow water calcium carbonate deposition/dissolution, an interpretation that does not conflict with pelagic sedimentary data from the central Pacific.

Seasonal and interannual variability of the eastern boundary circulation and hydrography off Angola

Science.gov (United States)

Tchipalanga, Pedro; Macuéria, Marissa; Dengler, Marcus; Ostrowski, Marek; Kopte, Robert; Brandt, Peter

2016-04-01

Coastal countries of southwest Africa strongly depend upon their ocean: societal development, fisheries, and tourism face important changes associated with climate variability and global change. As an example, Angolan fisheries are currently reporting reduced catches that may be associated to variability of the eastern boundary circulation and water masses along the Angolan continental margin. In an effort to enhance understanding of the seasonal and interannual variability of the boundary circulation and thermocline water masses and their relation to warm and cold events in South East Atlantic, existing in-situ observations from a multi-cruise program were analyzed. Repeated hydrography and ship-board ADCP measurements from the EAF - Nansen Project collected during the Austral summer and winter period between 1995 and 2014 are used. From the ship-board velocity measurements, the average eastern boundary circulation at 6°S, 9°S, 12°S, 15°S and 17°S is presented for the summer and winter period. CTD data collected during the 24 cruises along the Angolan continental margin exhibit elevated interannual variability of heat and salt content in the upper thermocline between 50 and 150m depth. Warm and cold anomalies in the upper thermocline are strongly correlated to the Angola-Benguela area index and precede the respective sea surface temperature signal. The known warm events in 2001 and 2011 are well represented in the subsurface data. This suggests that thermocline heat anomalies serve as a preconditioning for the occurrences of Benguela Niños/Niñas. The processes responsible for the interannual variability of thermocline heat and salt contend are discussed.

Incidental catches of pelagic megafauna by the Dutch pelagic fleet in the Mauritanian Exclusive Economic Zone during the years 1999 - 2003

NARCIS (Netherlands)

Hofstede, ter R.; Zeeberg, J.J.; Haan, de D.; Couperus, A.S.; Mantingh, I.T.

2004-01-01

This report presents all registered catches of pelagic megafauna by the Dutch pelagic fleet in the Mauritanian Exclusive Economic Zone during the years 1999-2003. ‘By-catches’ incidentally include large species, notably cetaceans, sea turtles, sharks, rays, and some large pelagic fish such as

Reorganization of a marine trophic network along an inshore-offshore gradient due to stronger pelagic-benthic coupling in coastal areas

Science.gov (United States)

Kopp, Dorothée; Lefebvre, Sébastien; Cachera, Marie; Villanueva, Maria Ching; Ernande, Bruno

2015-01-01

Recent theoretical considerations have highlighted the importance of the pelagic-benthic coupling in marine food webs. In continental shelf seas, it was hypothesized that the trophic network structure may change along an inshore-offshore gradient due to weakening of the pelagic-benthic coupling from coastal to offshore areas. We tested this assumption empirically using the eastern English Channel (EEC) as a case study. We sampled organisms from particulate organic matter to predatory fishes and used baseline-corrected carbon and nitrogen stable isotope ratios (δ13C and δ15N) to determine their trophic position. First, hierarchical clustering on δ13C and δ15N coupled to bootstrapping and estimates of the relative contribution of pelagic and benthic carbon sources to consumers' diet showed that, at mesoscale, the EEC food web forms a continuum of four trophic levels with trophic groups spread across a pelagic and a benthic trophic pathway. Second, based on the same methods, a discrete approach examined changes in the local food web structure across three depth strata in order to investigate the inshore-offshore gradient. It showed stronger pelagic-benthic coupling in shallow coastal areas mostly due to a reorganization of the upper consumers relative to the two trophic pathways, benthic carbon sources being available to pelagic consumers and, reciprocally, pelagic sources becoming accessible to benthic species. Third a continuous approach examined changes in the mean and variance of upper consumers' δ13C and δ15N with depth. It detected a significant decrease in δ13C variance and a significant increase in δ15N variance as depth increases. A theoretical two-source mixing model showed that an inshore-offshore decrease in the pelagic-benthic coupling was a sufficient condition to produce the δ13C variance pattern, thus supporting the conclusions of the discrete approach. These results suggest that environmental gradients such as the inshore-offshore one should

The Benguela upwelling system lying off southern Africa's west ...

African Journals Online (AJOL)

spamer

Africa's west coast is one of the world's four main upwelling ..... Regions of current shear, convergence and divergence, as well ..... between Cape Point and Danger Point in 1975. .... processes in relation to eastern boundary current pelagic.

76 FR 72643 - Western Pacific Pelagic Fisheries; Closure of the Hawaii Shallow-Set Pelagic Longline Fishery Due...

Science.gov (United States)

2011-11-25

.... 080225267-91393-03] RIN 0648-XA370 Western Pacific Pelagic Fisheries; Closure of the Hawaii Shallow- Set...: Temporary rule; fishery closure. SUMMARY: NMFS closes the shallow-set pelagic longline fishery north of the Equator for all vessels registered under the Hawaii longline limited access program. The shallow-set...

Microbiostratigraphy of the Berriasian-Valanginian boundary in eastern Crimea: foraminifers, ostracods, organic-walled dinoflagellate cysts

Science.gov (United States)

Savelieva, Yuliya N.; Shurekova, Olga V.; Feodorova, Anna A.; Grishchenko, Vladimir A.; Guzhikov, Andrei Yu.

2017-08-01

Thorough study of foraminifers, ostracods and dinoflagellate remnants from the Zavodskaya Balka and Koklyuk sections helps to characterize the detailed biostratigraphic division of the Berriasian / Valanginian boundary sequence in the Feodosiya district of eastern Crimea. The foraminifer and dinocyst associations from the lower part of the sequence are clearly comparable with common Berriasian associations throughout all Mountain Crimea. On the other hand, foraminifer, ostracod and dinocyst associations from its upper part have been recorded only in eastern Crimea. The upper foraminifer level corresponds to the boreal ammonite zones from the Tauricum-Verrucosum (Upper Berriasian-Valanginian). Most of the ostracod species are endemic. The base of the uppermost dinocyst level correlates with the Lower Valanginian Paratollia zone from north-western Europe.

Feeding habits of the dolphinfish (Coryphaena hippurus in the eastern Caribbean

Directory of Open Access Journals (Sweden)

Hazel A. Oxenford

1999-12-01

Full Text Available The dolphinfish, Coryphaena hippurus, is an oceanic epipelagic fish with economic importance to sport and commercial fisheries throughout its worldwide distribution in tropical and sub-tropical waters. In the eastern Caribbean, dolphinfish are generally piscivorous, eating a wide variety of fish species including small oceanic pelagic species (e.g. flyingfish, halfbeaks, man-o-war fish, sargassum and rough triggerfish, juveniles of large oceanic pelagic species (e.g. tunas, billfish, jacks, dolphinfish, and pelagic larvae of neritic, benthic species (e.g. flying gurnards, triggerfish, pufferfish, grunts. They also eat invertebrates (e.g. cephalopods, mysids, scyphozoans, suggesting that they are essentially non-selective foragers. This appears to be typical of dolphinfish from other locations and of tropical oceanic pelagic species in general. Post-larval flying gurnards and flyingfish rank as the most important prey species overall. However, the diet varies with season, and mysids are a very important component from October to December. Diet also varies slightly with predator size (small dolphinfish eat fewer flyingfish and more squid than larger sized dolphinfish, and with sex (males take proportionally more of the active, fast swimming species such as flyingfish, squid and dolphinfish than do females. From these results and a review of the literature to determine the diet of other tropical oceanic species and the predators of dolphinfish, it can be seen that predator-prey relationships and interspecies competition for food clearly involve other commercially important species. As such, interactions between the surface trolling dolphinfish fisheries, the surface gillnet flyingfish fisheries, and the subsurface longline tuna fisheries in the eastern Caribbean can be expected.

Identifying pelagic ecosystem indicators for management

DEFF Research Database (Denmark)

Trenkel, Verena; Hintzen, Niels; Rindorf, Anna

2013-01-01

When exploiting fish populations under the ecosystem approach, aiming for MSY is not necessarily sufficient to ensure wider ecosystem sustainability. All of the large stocks of pelagic fish are managed through harvest control rules based on an MSY approach. Ensuring good environmental status...... will probably require further constraints to be imposed by management. Most of the current paradigm with regards to GES for fisheries has been based on demersal fish. Pelagic fisheries and fish are operationally and biologically respectively different. We use the example of applying the ecosystem approach...... between objectives and indicators were explored for a range of examples highlighting the importance of the biology and the interaction between the pelagic ecosystem and humans. Considering MSY targets alone will not fulfil GES objectives with regards to e.g. genetic, phenotypic, and behavioural dimensions...

Can pelagic net heterotrophy account for carbon fluxes from eastern Canadian lakes?

International Nuclear Information System (INIS)

Dubois, Kristal; Carignan, Richard; Veizer, Jan

2009-01-01

Lakes worldwide are commonly oversaturated with CO 2 , however the source of this CO 2 oversaturation is not well understood. To examine the magnitude of the C flux to the atmosphere and determine if an excess of respiration (R) over gross primary production (GPP) is sufficient to account for this C flux, metabolic parameters and stable isotopes of dissolved O 2 and C were measured in 23 Quebec lakes. All of the lakes sampled were oversaturated with CO 2 over the sampling period, on average 221 ± 25%. However, little evidence was found to conclude that this CO 2 oversaturation was the result of an excess of pelagic R over GPP. In lakes Croche and a l'Ours, where CO 2 flux, R and GPP were measured weekly, the annual difference between pelagic GPP and R, or net primary production (NPP), was not sufficient to account for the size of the CO 2 flux to the atmosphere. In Lac Croche average annual NPP was 14.4 mg C m -2 d -1 while the average annual flux of CO 2 to the atmosphere was 34 mg C m -2 d -1 . In Lac a l'Ours average annual NPP was -9.1 mg C m -2 d -1 while the average annual flux of CO 2 to the atmosphere was 55 mg C m -2 d -1 . In all of the lakes sampled, O 2 saturation averaged 104.0 ± 1.7% during the ice-free season and the isotopic composition of dissolved O 2 (δ 18 O DO ) was 22.9 ± 0.3 per mille , lower than atmospheric values and indicative of net autotrophy. Carbon evasion was not a function of R, nor did the isotopic signature of dissolved CO 2 in the lakes present evidence of excess R over GPP. External inputs of C must therefore subsidize the lake to explain the continued CO 2 oversaturation. The isotopic composition of dissolved inorganic C (δ 13 C DIC ) indicates that the CO 2 oversaturation cannot be attributed to in situ aerobic respiration. δ 13 C DIC reveals a source of excess C enriched in 13 C, which may be accounted for by anaerobic sediment respiration or groundwater inputs followed by kinetic isotope fractionation during degassing

Nine years of mass transport data in the eastern boundary of the North Atlantic Subtropical Gyre

Science.gov (United States)

Fraile-Nuez, Eugenio; MachíN, Francisco; VéLez-Belchí, Pedro; López-Laatzen, Federico; Borges, Rafael; BeníTez-Barrios, Verónica; HernáNdez-Guerra, Alonso

2010-09-01

One of the longest current meter time series in the Lanzarote Passage in the eastern boundary of the North Atlantic Subtropical Gyre has been used to determine and quantify the 9-year mean transport, the inter-annual and seasonal mass transport variability for the three water masses present in the area. Results show North Atlantic Central Water (NACW) flowing southward in the upper levels with a mean mass transport of -0.81 ± 1.48 Sv, Antarctic Intermediate Water (AAIW) flowing northward at intermediate levels with a mean transport of +0.09 ± 0.57 Sv and Mediterranean Water (MW) flowing southward in the deep part of the passage with a mean transport of -0.05 ± 0.17 Sv. Harmonic and wavelet analysis show the presence of a seasonal pattern in the passage for the three water masses. A maximum southward transport in winter and spring has been observed for the NACW followed by a minimum in summer and fall. Near zero values during winter and spring are found for AAIW, with a maximum northward value in summer and a negative value in fall, when this water mass reverses its flow. MW has a similar seasonal pattern to NACW. The vertical structure in the Lanzarote Passage can be approximated by four significant oscillatory modes which cumulatively explain 86.4% of the variance. The strong transport fluctuation found at the seasonal and inter-annual timescales demonstrates that the Eastern Boundary Current transport has a strong impact on meridional overturning estimates, thus indicating that to understand Meridional Overturning Circulation variability, these transport estimates at the eastern Atlantic margin are necessary.

Large Pelagics Telephone Survey

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Telephone Survey (LPTS) collects fishing effort information directly from captains holding Highly Migratory Species (HMS) permits (required by...

Large Pelagics Biological Survey

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Biological Survey (LPBS) collects additional length and weight information and body parts such as otoliths, caudal vertebrae, dorsal spines, and...

Production regimes in four eastern boundary current systems

Science.gov (United States)

Carr, M. E.; Kearns, E. J.

2003-01-01

High productivity (maxima 3 g C m(sup -2)day(sup -1)) of the Eastern Boundary Currents (EBCs), i.e. the California, Peru-Humboldt, Canary and Benguela Currents, is driven by a combination of local forcing and large-scale circulation. The characteristics of the deep water brought to the surface by upwelling favorable winds depend on the large-scale circulation patterns. Here we use a new hydrographic and nutrient climatology together with satellite measurements ofthe wind vector, sea-surface temperature (SST), chlorophyll concentration, and primary production modeled from ocean color to quantify the meridional and seasonal patterns of upwelling dynamics and biological response. The unprecedented combination of data sets allows us to describe objectively the variability for small regions within each current and to characterize the governing factors for biological production. The temporal and spatial environmental variability was due in most regions to large-scale circulation, alone or in combination with offshore transport (local forcing). The observed meridional and seasonal patterns of biomass and primary production were most highlycorrelated to components representing large-scale circulation. The biomass sustained by a given nutrient concentration in the Atlantic EBCs was twice as large as that of the Pacific EBCs. This apparent greater efficiency may be due toavailability of iron, physical retention, or differences in planktonic community structure.

LATE PLIOCENE-HOLOCENE DEBRIS FLOW DEPOSITS IN THE IONIAN SEA (EASTERN MEDITERRANEAN

Directory of Open Access Journals (Sweden)

GIOVANNI ALOISI DE LARDEREL

1997-11-01

Full Text Available Widespread coring of the Eastern Mediterranean Basin has outlined the existence of a systematic relation between lithology of debris flow deposits and physiographic setting. Whilst the topographic highs are characterized by pelagic sedimentation, the basin floors are alternatively subject to pelagic sedimentation and re-sedimentation pro cesses. Amongst the latters, turbidity flows and debris flows are the most common transport mechanisms.In this paper we present the study of the debris flow pro cess in the Ionian Sea using visual description of cores, grain size, carbonate content and smear slide analysis carried out on gravity and piston cores recovered over the past 20 years. A distinction has been made between debris flow deposits originating from the continental margins (North Africa and Malta Escarpment and those emplaced in the small basins amidst the Calabrian and Mediterranean ridges "Cobblestone Topography". As a result of the difference in setting, the former debris flow deposits include a great variety of lithologies and ages whilst the latter involve the pelagic sediments forming the typical Eastern Mediterranean Plio-Quaternary succession. A detailed study of clast and matrix structures makes it possible to describe the flows in terms of existing classifications of sediment gravity flows and to assume a clast support mechanism. Finally, biostratigraphy coupled with the presence of widespread marker beds enabled us to estimate the age of emplacement of the deposits and to hypothesize a triggering mechanism for flow initiation. Three flows are strictly related to the pelagic turbidite named homogenite, triggered by the explosive eruption of the Santorini volcano (Minoan eruption and therefore have an estimated age of 3,500 BP. The other deposits have ages ranging from 9,000 BP to about 70,000 BP and were originated by debris flows triggered by events such as earthquakes and glacial low sea level stands.    

Downscaling biogeochemistry in the Benguela eastern boundary current

Science.gov (United States)

Machu, E.; Goubanova, K.; Le Vu, B.; Gutknecht, E.; Garçon, V.

2015-06-01

Dynamical downscaling is developed to better predict the regional impact of global changes in the framework of scenarios. As an intermediary step towards this objective we used the Regional Ocean Modeling System (ROMS) to downscale a low resolution coupled atmosphere-ocean global circulation model (AOGCM; IPSL-CM4) for simulating the recent-past dynamics and biogeochemistry of the Benguela eastern boundary current. Both physical and biogeochemical improvements are discussed over the present climate scenario (1980-1999) under the light of downscaling. Despite biases introduced through boundary conditions (atmospheric and oceanic), the physical and biogeochemical processes in the Benguela Upwelling System (BUS) have been improved by the ROMS model, relative to the IPSL-CM4 simulation. Nevertheless, using coarse-resolution AOGCM daily atmospheric forcing interpolated on ROMS grids resulted in a shifted SST seasonality in the southern BUS, a deterioration of the northern Benguela region and a very shallow mixed layer depth over the whole regional domain. We then investigated the effect of wind downscaling on ROMS solution. Together with a finer resolution of dynamical processes and of bathymetric features (continental shelf and Walvis Ridge), wind downscaling allowed correction of the seasonality, the mixed layer depth, and provided a better circulation over the domain and substantial modifications of subsurface biogeochemical properties. It has also changed the structure of the lower trophic levels by shifting large offshore areas from autotrophic to heterotrophic regimes with potential important consequences on ecosystem functioning. The regional downscaling also improved the phytoplankton distribution and the southward extension of low oxygen waters in the Northern Benguela. It allowed simulating low oxygen events in the northern BUS and highlighted a potential upscaling effect related to the nitrogen irrigation from the productive BUS towards the tropical

Can pelagic net heterotrophy account for carbon fluxes from eastern Canadian lakes?

Energy Technology Data Exchange (ETDEWEB)

Dubois, Kristal, E-mail: kristal.dubois@gmail.com [Ottawa-Carleton Geoscience Center, University of Ottawa, 140 Louis Pasteur, Ottawa, Ontario, K1N 6N5 (Canada); Carignan, Richard [Departement des Sciences Biologiques, Universite de Montreal C.P. 6128, succ. Centre-Ville, Montreal, Quebec, H3C 3J7 (Canada); Veizer, Jan [Ottawa-Carleton Geoscience Center, University of Ottawa, 140 Louis Pasteur, Ottawa, Ontario, K1N 6N5 (Canada)

2009-05-15

Lakes worldwide are commonly oversaturated with CO{sub 2}, however the source of this CO{sub 2} oversaturation is not well understood. To examine the magnitude of the C flux to the atmosphere and determine if an excess of respiration (R) over gross primary production (GPP) is sufficient to account for this C flux, metabolic parameters and stable isotopes of dissolved O{sub 2} and C were measured in 23 Quebec lakes. All of the lakes sampled were oversaturated with CO{sub 2} over the sampling period, on average 221 {+-} 25%. However, little evidence was found to conclude that this CO{sub 2} oversaturation was the result of an excess of pelagic R over GPP. In lakes Croche and a l'Ours, where CO{sub 2} flux, R and GPP were measured weekly, the annual difference between pelagic GPP and R, or net primary production (NPP), was not sufficient to account for the size of the CO{sub 2} flux to the atmosphere. In Lac Croche average annual NPP was 14.4 mg C m{sup -2} d{sup -1} while the average annual flux of CO{sub 2} to the atmosphere was 34 mg C m{sup -2} d{sup -1}. In Lac a l'Ours average annual NPP was -9.1 mg C m{sup -2} d{sup -1} while the average annual flux of CO{sub 2} to the atmosphere was 55 mg C m{sup -2} d{sup -1}. In all of the lakes sampled, O{sub 2} saturation averaged 104.0 {+-} 1.7% during the ice-free season and the isotopic composition of dissolved O{sub 2} ({delta}{sup 18}O{sub DO}) was 22.9 {+-} 0.3 per mille , lower than atmospheric values and indicative of net autotrophy. Carbon evasion was not a function of R, nor did the isotopic signature of dissolved CO{sub 2} in the lakes present evidence of excess R over GPP. External inputs of C must therefore subsidize the lake to explain the continued CO{sub 2} oversaturation. The isotopic composition of dissolved inorganic C ({delta}{sup 13}C{sub DIC}) indicates that the CO{sub 2} oversaturation cannot be attributed to in situ aerobic respiration. {delta}{sup 13}C{sub DIC} reveals a source of excess

78 FR 70015 - Proposed Information Collection; Comment Request; Large Pelagic Fishing Survey

Science.gov (United States)

2013-11-22

... Collection; Comment Request; Large Pelagic Fishing Survey AGENCY: National Oceanic and Atmospheric... effort to reduce paperwork and respondent burden, invites the general public and other Federal agencies... Pelagics Headboat Survey (LPHS) component. Increase the annual Large Pelagics Telephone Survey (LPTS...

Pelagic habitat: exploring the concept of good environmental status

DEFF Research Database (Denmark)

Dickey-Collas, Mark; McQuatters-Gollop, Abigail; Bresnan, Eileen

2017-01-01

Marine environmental legislation is increasingly expressing a need to consider the quality of pelagic habitats. This paper uses the European Union marine strategy framework to explore the concept of good environmental status (GES) of pelagic habitat with the aim to build a wider understanding of ...

Structure and composition of the plate-boundary slip zone for the 2011 Tohoku-Oki earthquake.

Science.gov (United States)

Chester, Frederick M; Rowe, Christie; Ujiie, Kohtaro; Kirkpatrick, James; Regalla, Christine; Remitti, Francesca; Moore, J Casey; Toy, Virginia; Wolfson-Schwehr, Monica; Bose, Santanu; Kameda, Jun; Mori, James J; Brodsky, Emily E; Eguchi, Nobuhisa; Toczko, Sean

2013-12-06

The mechanics of great subduction earthquakes are influenced by the frictional properties, structure, and composition of the plate-boundary fault. We present observations of the structure and composition of the shallow source fault of the 2011 Tohoku-Oki earthquake and tsunami from boreholes drilled by the Integrated Ocean Drilling Program Expedition 343 and 343T. Logging-while-drilling and core-sample observations show a single major plate-boundary fault accommodated the large slip of the Tohoku-Oki earthquake rupture, as well as nearly all the cumulative interplate motion at the drill site. The localization of deformation onto a limited thickness (less than 5 meters) of pelagic clay is the defining characteristic of the shallow earthquake fault, suggesting that the pelagic clay may be a regionally important control on tsunamigenic earthquakes.

The Tectonic Boundary Between Eastern Subbaisin and South-West Subbasin of the South China Sea Revealed from the Normalized Magnetic Source Strength

Science.gov (United States)

Guo, L.; Meng, X.

2014-12-01

The South China Sea (SCS), surrounded by the Eurasia, Pacific and India-Australia plates, is one of the largest marginal seas in the Western Pacific. It was formed by the interaction of the three plates and the seafloor spreading during Late Oligocene time to Early Miocene time. The boundary between Eastern Subbaisin and South-west Subbasin of the SCS has long been debated in the literature. Refining the boundary is one of the crucial tasks for correctly understanding the seafloor spreading model of the SCS. Due to few drills on the deep ocean basin of the SCS, magnetic data become important information for refining the boundary. However, the interpretation of magnetic data in the SCS suffers from the remanent magnetization of ocean crust as well as igneous rock and seamounts. The conventional reduction-to-pole anomalies at low latitudes usually neglect the remanent magnetization, making the interpretation incorrect. Here, we assembled high-resolution total magnetic intensity (TMI) data around the ocean basin of the SCS, and then did a special transformation of the TMI anomalies with a varying magnetic inclinations algorithm to obtain the normalized source strength (NSS). The NSS has advantage of insensitivity to remanent magnetization, benefitting correct interpretation. The NSS presents discriminative features from east to west in the ocean basin. The boundary of the discriminative features is clear and just ranges from the northeastern edge of the Zhongsha Islands running in the southeast direction to the northeastern edge of the Reed Bank. These imply that magnetic structure and tectonic features in the crust are discriminative between both sides of this boundary. It can be deduced that this boundary is the tectonic boundary between Eastern Subbaisin and South-west Subbasin. We acknowledge the financial support of the National Natural Science Foundation of China (41374093) and the SinoProbe-01-05 project.

Vertical structure, biomass and topographic association of deep-pelagic fishes in relation to a mid-ocean ridge system

Science.gov (United States)

Sutton, T. T.; Porteiro, F. M.; Heino, M.; Byrkjedal, I.; Langhelle, G.; Anderson, C. I. H.; Horne, J.; Søiland, H.; Falkenhaug, T.; Godø, O. R.; Bergstad, O. A.

2008-01-01

The assemblage structure and vertical distribution of deep-pelagic fishes relative to a mid-ocean ridge system are described from an acoustic and discrete-depth trawling survey conducted as part of the international Census of Marine Life field project MAR-ECO . The 36-station, zig-zag survey along the northern Mid-Atlantic Ridge (MAR; Iceland to the Azores) covered the full depth range (0 to >3000 m), from the surface to near the bottom, using a combination of gear types to gain a more comprehensive understanding of the pelagic fauna. Abundance per volume of deep-pelagic fishes was highest in the epipelagic zone and within the benthic boundary layer (BBL; 0-200 m above the seafloor). Minimum fish abundance occurred at depths below 2300 m but above the BBL. Biomass per volume of deep-pelagic fishes over the MAR reached a maximum within the BBL, revealing a previously unknown topographic association of a bathypelagic fish assemblage with a mid-ocean ridge system. With the exception of the BBL, biomass per volume reached a water column maximum in the bathypelagic zone between 1500 and 2300 m. This stands in stark contrast to the general "open-ocean" paradigm that biomass decreases exponentially from the surface downwards. As much of the summit of the MAR extends into this depth layer, a likely explanation for this mid-water maximum is ridge association. Multivariate statistical analyses suggest that the dominant component of deep-pelagic fish biomass over the northern MAR was a wide-ranging bathypelagic assemblage that was remarkably consistent along the length of the ridge from Iceland to the Azores. Integrating these results with those of previous studies in oceanic ecosystems, there appears to be adequate evidence to conclude that special hydrodynamic and biotic features of mid-ocean ridge systems cause changes in the ecological structure of deep-pelagic fish assemblages relative to those at the same depths over abyssal plains. Lacking terrigenous input of

Paleoenvironmental changes across the Cretaceous/Tertiary boundary at Flaxbourne River and Woodside Creek, eastern Marlborough, New Zealand

International Nuclear Information System (INIS)

Hollis, C.J.; Strong, C.P.; Rodgers, K.A.; Rogers, K.M.

2003-01-01

An integrated study of variation in siliceous microfossils, lithofacies, and other geochemical guides to environmental conditions through the Cretaceous/Tertiary (K/T) boundary transition at Flaxbourne River and Woodside Creek, coastal eastern Marlborough, indicates that the K/T impact disrupted oceanic conditions along the continental margin of eastern New Zealand for c. 1 m.y. Initial effects of the K/T event were a major reduction in carbonate production, associated with calcareous plankton extinctions, and significant increases in terrigenous clay and biogenic silica content. An absence of radiolarian extinctions or significant negative excursions in paleo-productivity indicators (Ba, delta 13 C at the boundary, followed by rapid increases in the abundance of diatoms and spumellarian radiolarians, indicate that biogenic silica production partly compensated for the collapse in calcareous plankton. The earliest Paleocene recovery of calcareous plankton was short-lived, giving way to a progressive increase in siliceous plankton abundance over c. 500,000 yr, which culminated in a c. 400,000 yr episode of peak biogenic silica production. The dominance of siliceous facies, coupled with the abundance of diatoms and spumellarian radiolarians, indicates climatic or oceanic conditions were significantly cooler than in the Late Cretaceous. Stepped increases in biogenic silica production show c. 100,000 yr periodicity, suggesting that Early Paleocene lithofacies changes were influenced by climate forcing agents at the eccentricity bandwidth. (author). 83 refs., 11 figs., 3 tabs

Hf Isotope Evidence for Subducted Basalt and Sediment Contributions to the Eastern Trans-Mexican Volcanic Belt

Science.gov (United States)

Cai, Y.; Tuena, A. G.; Capra, L.; Straub, S. M.; Goldstein, S. L.; Langmuir, C. H.

2005-12-01

Magmas generated at thick crust continental arcs often have enriched continental crust-like trace element patterns and Pb-Sr-Nd isotope ratios that are intermediate to both upper mantle and crustal compositions. Thus it is difficult to distinguish between contributions from (a) the subducted basalt and the upper mantle wedge, and (b) subducted sediment and the continental crust. These issues have been the focus of major controversy. Here we show evidence for subduction contributions to lavas in a classic thick crust environment. In Eastern Trans-Mexican Volcanic Belt, the upper continental crust is 30 km to 45 km thick. However, primitive mafic lavas erupt on many sites across the arc. We have analyzed the subducting sediments as represented by DSDP 487, located seaward of the trench, where the lower third of the sediment column has strongly hydrothermal pelagic features and the upper two-thirds is composed of terrigenous sediments. The pelagic sediments have distinctive features that could be used to identify a subduction component in the volcanics, including high REE/Hf, negative Ce anomalies, and Nd-Hf isotopes that lie on the "seawater array" and offset from the "mantle-crust" array. We have focused on a unique series of lavas from volcano Nevado de Toluca, located southwest of Mexico City. These lavas show negative Ce anomalies coupled with low REE/Hf and Zr/Nd ratios. Hf-Nd isotope ratios show a shallow trend compared to the mantle-crust array, consistent with a pelagic component. In addition, Hf isotopes show a striking positive correlation with Ce anomalies that trend toward the pelagic sediment compositions. These and other observations provide clear evidence for a component from subducted sediment in the lavas. In addition, there is a negative correlation of Lu/Hf and Hf isotopes that requires a mixing endmember with MORB-like Hf isotope ratios but with lower than MORB Lu/Hf. This indicates a melt from eclogitic subducted basalt. Compared to other

Complex small pelagic fish population patterns arising from individual behavioral responses to their environment

Science.gov (United States)

Brochier, Timothée; Auger, Pierre-Amaël; Pecquerie, Laure; Machu, Eric; Capet, Xavier; Thiaw, Modou; Mbaye, Baye Cheikh; Braham, Cheikh-Baye; Ettahiri, Omar; Charouki, Najib; Sène, Ousseynou Ndaw; Werner, Francisco; Brehmer, Patrice

2018-05-01

Small pelagic fish (SPF) species are heavily exploited in eastern boundary upwelling systems (EBUS) as their transformation products are increasingly used in the world's food chain. Management relies on regular monitoring, but there is a lack of robust theories for the emergence of the populations' traits and their evolution in highly variable environments. This work aims to address existing knowledge gaps by combining physical and biogeochemical modelling with an individual life-cycle based model applied to round sardinella (Sardinella aurita) off northwest Africa, a key species for regional food security. Our approach focused on the processes responsible for seasonal migrations, spatio-temporal size-structure, and interannual biomass fluctuations. Emergence of preferred habitat resulted from interactions between natal homing behavior and environmental variability that impacts early life stages. Exploration of the environment by the fishes was determined by swimming capabilities, mesoscale to regional habitat structure, and horizontal currents. Fish spatio-temporal abundance variability emerged from a complex combination of distinct life-history traits. An alongshore gradient in fish size distributions is reported and validated by in situ measurements. New insights into population structure are provided, within an area where the species is abundant year-round (Mauritania) and with latitudinal migrations of variable (300-1200 km) amplitude. Interannual biomass fluctuations were linked to modulations of fish recruitment over the Sahara Bank driven by variability in alongshore current intensity. The identified processes constitute an analytical framework that can be implemented in other EBUS and used to explore impacts of regional climate change on SPF.

Fractal Hypothesis of the Pelagic Microbial Ecosystem—Can Simple Ecological Principles Lead to Self-Similar Complexity in the Pelagic Microbial Food Web?

Science.gov (United States)

Våge, Selina; Thingstad, T. Frede

2015-01-01

Trophic interactions are highly complex and modern sequencing techniques reveal enormous biodiversity across multiple scales in marine microbial communities. Within the chemically and physically relatively homogeneous pelagic environment, this calls for an explanation beyond spatial and temporal heterogeneity. Based on observations of simple parasite-host and predator-prey interactions occurring at different trophic levels and levels of phylogenetic resolution, we present a theoretical perspective on this enormous biodiversity, discussing in particular self-similar aspects of pelagic microbial food web organization. Fractal methods have been used to describe a variety of natural phenomena, with studies of habitat structures being an application in ecology. In contrast to mathematical fractals where pattern generating rules are readily known, however, identifying mechanisms that lead to natural fractals is not straight-forward. Here we put forward the hypothesis that trophic interactions between pelagic microbes may be organized in a fractal-like manner, with the emergent network resembling the structure of the Sierpinski triangle. We discuss a mechanism that could be underlying the formation of repeated patterns at different trophic levels and discuss how this may help understand characteristic biomass size-spectra that hint at scale-invariant properties of the pelagic environment. If the idea of simple underlying principles leading to a fractal-like organization of the pelagic food web could be formalized, this would extend an ecologists mindset on how biological complexity could be accounted for. It may furthermore benefit ecosystem modeling by facilitating adequate model resolution across multiple scales. PMID:26648929

Benthic life in the pelagic: Aggregate encounter and degradation rates by pelagic harpacticoid copepods

DEFF Research Database (Denmark)

Koski, Marja; Kiørboe, Thomas; Takahashi, K.

2005-01-01

We measured field abundances, feeding rates, swimming behavior, and particle colonization of two harpacticoids, the pelagic Microsetella norvegica and the semibenthic Amonardia normanni, to examine (1) if aggregates have a significant role in harpacticoid nutrition and (2) if harpacticoids...

Vertical distribution of pelagic photosynthesis

DEFF Research Database (Denmark)

Lyngsgaard, Maren Moltke

chlorophyll maxima (DCM) to be a general feature in the ocean. Today, it is generally accepted that DCMs occur in most of our oceans still, despite this empirical knowledge, subsurface primary production is still largely ignored in marine science. The work included in this PhD examines the vertical...... each of the three regions combined with 15 years of survey data for the Baltic Sea transition zone. Overall, the results of this PhD work show that the vertical distribution of phytoplankton and their activity is important for the understanding, dynamics and functioning of pelagic ecosystems. It, thus......, emphasizes that future research and modelling exercises aimed at improving understanding of pelagic ecosystems and their role in the global ocean should include a consideration of the vertical heterogeneity in phytoplankton distributions and activity....

NEFSC Small Pelagics Acoustic/Midwater Trawl Survey (DE9903, EK500)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The small pelagics cruise will map the distribution of small pelagic species such as Atlantic mackerel, Atlantic herring, silver hake, butterfish, and squid, in the...

The Ecuadorian Artisanal Fishery for Large Pelagics: Species Composition and Spatio-Temporal Dynamics.

Directory of Open Access Journals (Sweden)

Jimmy Martínez-Ortiz

Full Text Available The artisanal fisheries of Ecuador operate within one of the most dynamic and productive marine ecosystems of the world. This study investigates the catch composition of the Ecuadorian artisanal fishery for large pelagic fishes, including aspects of its spatio-temporal dynamics. The analyses of this study are based on the most extensive dataset available to date for this fishery: a total of 106,963 trip-landing inspection records collected at its five principal ports during 2008 ‒ 2012. Ecuadorian artisanal fisheries remove a substantial amount of biomass from the upper trophic-level predatory fish community of the eastern tropical Pacific Ocean. It is estimated that at least 135 thousand metric tons (mt (about 15.5 million fish were landed in the five principal ports during the study period. The great novelty of Ecuadorian artisanal fisheries is the "oceanic-artisanal" fleet component, which consists of mother-ship (nodriza boats with their towed fiber-glass skiffs (fibras operating with pelagic longlines. This fleet has fully expanded into oceanic waters as far offshore as 100°W, west of the Galapagos Archipelago. It is estimated that nodriza operations produce as much as 80% of the total catches of the artisanal fishery. The remainder is produced by independent fibras operating in inshore waters with pelagic longlines and/or surface gillnets. A multivariate regression tree analysis was used to investigate spatio-environmental effects on the nodriza fleet (n = 6,821 trips. The catch species composition of the nodriza fleet is strongly influenced by the northwesterly circulation of the Humboldt Current along the coast of Peru and its associated cold waters masses. The target species and longline gear-type used by nodrizas change seasonally with the incursion of cool waters (< 25°C from the south and offshore. During this season, dolphinfish (Coryphaena hippurus dominates the catches. However, in warmer waters, the fishery changes to tuna

The Ecuadorian Artisanal Fishery for Large Pelagics: Species Composition and Spatio-Temporal Dynamics.

Science.gov (United States)

Martínez-Ortiz, Jimmy; Aires-da-Silva, Alexandre M; Lennert-Cody, Cleridy E; Maunder, Mark N

2015-01-01

The artisanal fisheries of Ecuador operate within one of the most dynamic and productive marine ecosystems of the world. This study investigates the catch composition of the Ecuadorian artisanal fishery for large pelagic fishes, including aspects of its spatio-temporal dynamics. The analyses of this study are based on the most extensive dataset available to date for this fishery: a total of 106,963 trip-landing inspection records collected at its five principal ports during 2008 ‒ 2012. Ecuadorian artisanal fisheries remove a substantial amount of biomass from the upper trophic-level predatory fish community of the eastern tropical Pacific Ocean. It is estimated that at least 135 thousand metric tons (mt) (about 15.5 million fish) were landed in the five principal ports during the study period. The great novelty of Ecuadorian artisanal fisheries is the "oceanic-artisanal" fleet component, which consists of mother-ship (nodriza) boats with their towed fiber-glass skiffs (fibras) operating with pelagic longlines. This fleet has fully expanded into oceanic waters as far offshore as 100°W, west of the Galapagos Archipelago. It is estimated that nodriza operations produce as much as 80% of the total catches of the artisanal fishery. The remainder is produced by independent fibras operating in inshore waters with pelagic longlines and/or surface gillnets. A multivariate regression tree analysis was used to investigate spatio-environmental effects on the nodriza fleet (n = 6,821 trips). The catch species composition of the nodriza fleet is strongly influenced by the northwesterly circulation of the Humboldt Current along the coast of Peru and its associated cold waters masses. The target species and longline gear-type used by nodrizas change seasonally with the incursion of cool waters (< 25°C) from the south and offshore. During this season, dolphinfish (Coryphaena hippurus) dominates the catches. However, in warmer waters, the fishery changes to tuna

A Pelagic Paleocene Seouence in the Biga Peninsula Northwest Turkey

Directory of Open Access Journals (Sweden)

M. Burak YIKILMAZ

2002-06-01

Full Text Available A sequence of pelagic limestone, calciturbidite, debris flow, greywacke, basalt and limestone blocks. up to several hundred metres across, occur west of the town of Biga in northwest Turkey. The pelagic limestones in this sequence, named as the Ballıkaya formation, comprise pelagic foraminifera of Palaeocene age. Neritic limestone of Mid-Eocene age lies unconformably over the Ballıkaya formation. The age and the sedimentary environment of the Ballıkaya formation indicate the presence of a tectonically active deep-sea environment in northwest Turkey during the Palaeocene, and constrain the main Alpide deformation in northwest Turkey to the Late Palaeocene - Early Eocene interval.

OWEZ pelagic fish, progress report and progression after T1

NARCIS (Netherlands)

Ybema, M.S.; Gloe, D.; Lambers, R.H.L.

2009-01-01

This report presents the current status of pelagic fish research in the Offshore Windfarm Egmond aan Zee (OWEZ) after having finalized the T0 baseline survey in 2003 and the T1 survey after construction of the wind farm in 2007. The T0 study indicated a highly dynamic pelagic fish community along

Pelagic shark bycatch in the tuna- and swordfish-directed longline ...

African Journals Online (AJOL)

The capture of pelagic sharks as bycatch of the South African pelagic longline fleet targeting tuna Thunnus spp. and swordfish Xiphias gladius was investigated during the period 1998–2005. In all, 26 species were caught, of which six are listed by the International Union for Conservation of Nature (IUCN) as Vulnerable and ...

Seamounts are hotspots of pelagic biodiversity in the open ocean.

Science.gov (United States)

Morato, Telmo; Hoyle, Simon D; Allain, Valerie; Nicol, Simon J

2010-05-25

The identification of biodiversity hotspots and their management for conservation have been hypothesized as effective ways to protect many species. There has been a significant effort to identify and map these areas at a global scale, but the coarse resolution of most datasets masks the small-scale patterns associated with coastal habitats or seamounts. Here we used tuna longline observer data to investigate the role of seamounts in aggregating large pelagic biodiversity and to identify which pelagic species are associated with seamounts. Our analysis indicates that seamounts are hotspots of pelagic biodiversity. Higher species richness was detected in association with seamounts than with coastal or oceanic areas. Seamounts were found to have higher species diversity within 30-40 km of the summit, whereas for sets close to coastal habitat the diversity was lower and fairly constant with distance. Higher probability of capture and higher number of fish caught were detected for some shark, billfish, tuna, and other by-catch species. The study supports hypotheses that seamounts may be areas of special interest for management for marine pelagic predators.

Turtle bycatch in the pelagic longline fishery off southern Africa ...

African Journals Online (AJOL)

Capture by pelagic longline fisheries has been identified as a key threat to turtle populations. This study is the first assessment of turtle bycatch in the South African pelagic longline fishery for tunas Thunnus spp. and swordfish Xiphias gladius. A total of 181 turtles was caught on observed sets between 1998 and 2005, at a ...

Pelagic fish stock assessment by acoustic methods at Ifremer

OpenAIRE

Doray, Mathieu; Masse, Jacques; Petitgas, Pierre; Doray, Mathieu; Masse, Jacques; Petitgas, Pierre

2010-01-01

The main objective of Ifremer's pelagic sea surveys (Pelgas in the Bay of Biscay and Pelmed in the Gulf of Lion) is to assess the biomass of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) populations, based on fisheries acoustic data. Complementary data on the whole pelagic ecosystem (hydrology, plankton, fish eggs and larvae, other fish species, seabirds and marine mammals) are also collected during the cruises. This document describes the procedures used to derive stock a...

76 FR 13297 - Western Pacific Pelagic Fisheries; Hawaii-Based Shallow-set Longline Fishery; Court Order

Science.gov (United States)

2011-03-11

.... 100826393-1171-01] RIN 0648-BA19 Western Pacific Pelagic Fisheries; Hawaii-Based Shallow-set Longline... allowable incidental interactions that may occur between the Hawaii-based shallow-set pelagic longline... to optimize yield from the Hawaii-based pelagic shallow-set longline fishery without jeopardizing the...

Olfaction Contributes to Pelagic Navigation in a Coastal Shark.

Science.gov (United States)

Nosal, Andrew P; Chao, Yi; Farrara, John D; Chai, Fei; Hastings, Philip A

2016-01-01

How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.

Internal waves and modern and ancient hiatuses in pelagic caps of Pacific guyots and seamounts

Science.gov (United States)

Mitchell, Neil; Simmons, Harper; Lear, Carrie

2013-04-01

Locations of recent non-deposition and ancient hiatuses in the pelagic caps of guyots and seamounts are compared with paleotemperature and physiographic information to speculate on the character of internal tidal waves in the upper Pacific Ocean through the Cenozoic. Internal tidal waves are generated where the ocean barotropic tide passes over the Hawaiian and other major ridges in the Pacific basin. Drill core and geophysical evidence for sediment accumulation, non-deposition or erosion are used to classify broadly sites as either accumulating or eroding/non-depositing in the recent geological past. When these classified sites are compared against results of a numerical model of the internal tide field (Simmons, Ocean Mod. 2008), the sites accumulating particles over the past few million years are all found to lie away from beams of the modeled internal tide, while those that have not been accumulating are in areas of high internal wave energy. Given the correspondence to modern internal wave conditions, we examine whether internal tides can explain ancient hiatuses at the drill sites. For example, Late Cenozoic pelagic caps on guyots among the Marshall Islands contain two hiatuses of broadly similar age, but the dates of the first pelagic sediments deposited following each hiatus do not correlate between guyots, suggesting that they originate not from universal factors (e.g., water chemistry) but local, probably physical factors, such as internal tides. We investigate how changing boundary conditions such as ocean temperature and basin physiography may have affected the geometry and vigour of internal tides through the Cenozoic. Changes in the geometry of ridges underlying the Solomon, Bonin and Marianas Island chains caused by plate tectonics and subsidence may be responsible for sediment hiatuses at these far-field guyot sites.

Under pressure: Climate change, upwelling and eastern boundary upwelling ecosystems

Directory of Open Access Journals (Sweden)

Marisol eGarcía-Reyes

2015-12-01

Full Text Available The IPCC AR5 provided an overview of the likely effects of climate change on Eastern Boundary Upwelling Systems (EBUS, stimulating increased interest in research examining the issue. We use these recent studies to develop a new synthesis describing climate change impacts on EBUS. We find that model and observational data suggest coastal upwelling-favorable winds in poleward portions of EBUS have intensified and will continue to do so in the future. Although evidence is weak in data that are presently available, future projections show that this pattern might be driven by changes in the positioning of the oceanic high-pressure systems rather than by deepening of the continental low-pressure systems, as previously proposed. There is low confidence regarding the future effects of climate change on coastal temperatures and biogeochemistry due to uncertainty in the countervailing responses to increasing upwelling and coastal warming, the latter of which could increase thermal stratification and render upwelling less effective in lifting nutrient-rich deep waters into the photic zone. Although predictions of ecosystem responses are uncertain, EBUS experience considerable natural variability and may be inherently resilient. However, multi-trophic level, end-to-end (i.e., winds to whales studies are needed to resolve the resilience of EBUS to climate change, especially their response to long-term trends or extremes that exceed pre-industrial ranges.

Adaptation of pelage color and pigment variations in Israeli subterranean blind mole rats, Spalax ehrenbergi [corrected].

Directory of Open Access Journals (Sweden)

Natarajan Singaravelan

Full Text Available Concealing coloration in rodents is well established. However, only a few studies examined how soil color, pelage color, hair-melanin content, and genetics (i.e., the causal chain synergize to configure it. This study investigates the causal chain of dorsal coloration in Israeli subterranean blind mole rats, Spalax ehrenbergi.We examined pelage coloration of 128 adult animals from 11 populations belonging to four species of Spalax ehrenbergi superspecies (Spalax galili, Spalax golani, Spalax carmeli, and Spalax judaei and the corresponding coloration of soil samples from the collection sites using a digital colorimeter. Additionally, we quantified hair-melanin contents of 67 animals using HPLC and sequenced the MC1R gene in 68 individuals from all four mole rat species.Due to high variability of soil colors, the correlation between soil and pelage color coordinates was weak and significant only between soil hue and pelage lightness. Multiple stepwise forward regression revealed that soil lightness was significantly associated with all pelage color variables. Pelage color lightness among the four species increased with the higher southward aridity in accordance to Gloger's rule (darker in humid habitats and lighter in arid habitats. Darker and lighter pelage colors are associated with darker basalt and terra rossa, and lighter rendzina soils, respectively. Despite soil lightness varying significantly, pelage lightness and eumelanin converged among populations living in similar soil types. Partial sequencing of the MC1R gene identified three allelic variants, two of which were predominant in northern species (S. galili and S. golani, and the third was exclusive to southern species (S. carmeli and S. judaei, which might have caused the differences found in pheomelanin/eumelanin ratio.Darker dorsal pelage in darker basalt and terra rossa soils in the north and lighter pelage in rendzina and loess soils in the south reflect the combined results of

Crustal Structure and Evolution of the Eastern Himalayan Plate Boundary System, Northeast India

Science.gov (United States)

Mitra, S.; Priestley, K. F.; Borah, Kajaljyoti; Gaur, V. K.

2018-01-01

We use data from 24 broadband seismographs located south of the Eastern Himalayan plate boundary system to investigate the crustal structure beneath Northeast India. P wave receiver function analysis reveals felsic continental crust beneath the Brahmaputra Valley, Shillong Plateau and Mikir Hills, and mafic thinned passive margin transitional crust (basement layer) beneath the Bengal Basin. Within the continental crust, the central Shillong Plateau and Mikir Hills have the thinnest crust (30 ± 2 km) with similar velocity structure, suggesting a unified origin and uplift history. North of the plateau and Mikir Hills the crustal thickness increases sharply by 8-10 km and is modeled by ˜30∘ north dipping Moho flexure. South of the plateau, across the ˜1 km topographic relief of the Dawki Fault, the crustal thickness increases abruptly by 12-13 km and is modeled by downfaulting of the plateau crust, overlain by 13-14 km thick sedimentary layer/rocks of the Bengal Basin. Farther south, beneath central Bengal Basin, the basement layer is thinner (20-22 km) and has higher Vs (˜4.1 km s-1) indicating a transitional crystalline crust, overlain by the thickest sedimentary layer/rocks (18-20 km). Our models suggest that the uplift of the Shillong Plateau occurred by thrust faulting on the reactivated Dawki Fault, a continent margin paleorift fault, and subsequent back thrusting on the south dipping Oldham Fault, in response to flexural loading of the Eastern Himalaya. Our estimated Dawki Fault offset combined with timing of surface uplift of the plateau reveals a reasonable match between long-term uplift and convergence rate across the Dawki Fault with present-day GPS velocities.

Pelagic Dealer Commercial Landings Monitoring (HMS Dealers)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains summarized pounds of select pelagic fish species bought by selected federally permitted seafood dealers in the SE Region of the US mainland....

76 FR 23964 - Fisheries in the Western Pacific; Pelagic Fisheries; Purse Seine Prohibited Areas Around American...

Science.gov (United States)

2011-04-29

... are managed under the Pelagics FEP. The Council prepared Amendment 3 to the Pelagics FEP to address... animals, such as pelagic fishes and sea turtles, tend to congregate to naturally-occurring floating..., vessel monitoring system (VMS), and the use of safe sea turtle handling techniques. BILLING CODE 3510-22...

Regional Wave Climates along Eastern Boundary Currents

Science.gov (United States)

Semedo, Alvaro; Soares, Pedro

2016-04-01

Two types of wind-generated gravity waves coexist at the ocean surface: wind sea and swell. Wind sea waves are waves under growing process. These young growing waves receive energy from the overlaying wind and are strongly coupled to the local wind field. Waves that propagate away from their generation area and no longer receive energy input from the local wind are called swell. Swell waves can travel long distances across entire ocean basins. A qualitative study of the ocean waves from a locally vs. remotely generation perspective is important, since the air sea interaction processes is strongly modulated by waves and vary accordingly to the prevalence of wind sea or swell waves in the area. A detailed climatology of wind sea and swell waves along eastern boundary currents (EBC; California Current, Canary Current, in the Northern Hemisphere, and Humboldt Current, Benguela Current, and Western Australia Current, in the Southern Hemisphere), based on the ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis will be presented. The wind regime along EBC varies significantly from winter to summer. The high summer wind speeds along EBC generate higher locally generated wind sea waves, whereas lower winter wind speeds in these areas, along with stronger winter extratropical storms far away, lead to a predominance of swell waves there. In summer, the coast parallel winds also interact with coastal headlands, increasing the wind speed through a process called "expansion fan", which leads to an increase in the height of locally generated waves downwind of capes and points. Hence the spatial patterns of the wind sea or swell regional wave fields are shown to be different from the open ocean along EBC, due to coastal geometry and fetch dimensions. Swell waves will be shown to be considerably more prevalent and to carry more energy in winter along EBC, while in summer locally generated wind sea waves are either more comparable to swell waves or

76 FR 37761 - Fisheries Off West Coast States; Coastal Pelagic Species Fisheries; Amendment 13 to the Coastal...

Science.gov (United States)

2011-06-28

.... 110606318-1319-01] RIN 0648-BA68 Fisheries Off West Coast States; Coastal Pelagic Species Fisheries; Amendment 13 to the Coastal Pelagic Species Fishery Management Plan; Annual Catch Limits AGENCY: National... the Coastal Pelagic Species (CPS) Fishery Management Plan (FMP). This proposed rule will implement...

78 FR 54482 - Eastern States: Filing of Plats of Survey

Science.gov (United States)

2013-09-04

... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLES956000-L14200000-BK0000] Eastern States... the Federal Register, Volume 78, Number 2, on pages 318-319 a notice entitled ``Eastern States: Filing... resurvey of a portion of the Qualla Indian Boundary, land held in trust for the Eastern Band of Cherokee...

Factors affecting the species composition of arable field boundary vegetation

NARCIS (Netherlands)

Kleijn, D.; Verbeek, M.

2000-01-01

1. In recent decades the botanical diversity of arable field boundaries has declined drastically. To determine the most important factors related to the species composition of arable field boundaries, the vegetation composition of 105 herbaceous boundaries, 1-m wide, in the central and eastern

Female-biased sex ratios in marine pelagic copepods: Comment on Gusmao et al. (2013)

DEFF Research Database (Denmark)

Hirst, Andrew G.; Bonnet, D; Conway, DVP

2013-01-01

Gusmao et al. (2013; Mar Ecol Prog Ser 482:279-298) review causes of sex ratio skew in pelagic copepods and in doing so repeatedly dispute the paper of Hirst et al. (2010) ‘Does predation control adult sex ratios and longevities in marine pelagic copepods?’ Here we respond to some important error...... in their citation of our paper and briefly highlight where future work is needed in order to attribute the causes of strong sex ratio skew seen in some copepod families......Gusmao et al. (2013; Mar Ecol Prog Ser 482:279-298) review causes of sex ratio skew in pelagic copepods and in doing so repeatedly dispute the paper of Hirst et al. (2010) ‘Does predation control adult sex ratios and longevities in marine pelagic copepods?’ Here we respond to some important errors...

Interspecies and spatial trends in polycyclic aromatic hydrocarbons (PAHs) in Atlantic and Mediterranean pelagic seabirds

International Nuclear Information System (INIS)

Roscales, Jose L.; Gonzalez-Solis, Jacob; Calabuig, Pascual; Jimenez, Begona

2011-01-01

PAHs were analyzed in the liver of 5 species of pelagic seabirds (Procellariiformes) from the northeast Atlantic and the Mediterranean. The main objective was to assess the trophic and geographic trends of PAHs in seabirds to evaluate their suitability as bioindicators of chronic marine pollution by these compounds. Although higher levels of PAHs have been described in the Mediterranean compared to other oceanic regions, we did not find significant spatial patterns and observed only minor effects of the geographic origin on seabird PAHs. However, we found significant higher PAH levels in petrel compared to shearwater species, which could be related to differences in their exploitation of mesopelagic and epipelagic resources, respectively, and the vertical dynamic of PAHs in the water column. Overall, although this study enhances the need of multi-species approaches to show a more comprehensive evaluation of marine pollution, seabirds emerged as poor indicators of pelagic chronic PAH levels. - Highlights: → PAHs in pelagic seabirds show specific inter-species patterns related to trophic ecology. → Geographic origin shows a minor effect over PAH levels in pelagic seabirds. → Pelagic seabirds seem to be poor indicators of chronic PAH levels. - PAH levels in Atlantic and Mediterranean pelagic seabirds show specific inter-species patterns related to trophic ecology but a minor influence of their geographic origin.

Growth Rate Potential of Juvenile Sockeye Salmon in Warmer and Cooler Years on the Eastern Bering Sea Shelf

Directory of Open Access Journals (Sweden)

Edward V. Farley

2009-01-01

Full Text Available A spatially explicit bioenergetics model was used to predict juvenile sockeye salmon Oncorhynchus nerka growth rate potential (GRP on the eastern Bering Sea shelf during years with cooler and warmer spring sea surface temperatures (SSTs. Annual averages of juvenile sockeye salmon GRP were generally lower among years with cooler SSTs and generally higher in offshore than nearshore regions of the eastern Bering Sea shelf during years with warmer SSTs. Juvenile sockeye salmon distribution was significantly (P<.05 related to GRP and their prey densities were positively related to spring SST (P<.05. Juvenile sockeye salmon GRP was more sensitive to changes in prey density and observed SSTs during years when spring SSTs were warmer (2002, 2003, and 2005. Our results suggest that the pelagic productivity on the eastern Bering Sea shelf was higher during years with warmer spring SSTs and highlight the importance of bottom-up control on the eastern Bering Sea ecosystem.

Seasonal changes of the pelagic fish assemblage in a temperate estuary

Science.gov (United States)

Hagan, S. M.; Able, K. W.

2003-01-01

The pelagic (i.e. fishes that spend most of their time swimming and feeding in the water column) fish assemblage was examined within a temperate estuary to determine the seasonal patterns of abundance, biomass, richness, and species composition. These measures were related to abiotic measures including temperature, salinity, water transparency, and depth. Pelagic fish (nGasterosteus aculeatus and age 1+ by M. menidia. Spring (April-early June) was overwhelmingly dominated by age 0+ C. harengus. Early summer (late June-early July) was relatively species rich and characterized by age 0+ of Brevoortia tyrannus, Pomatomus saltatrix, Alosa pseudoharengus, and age 1+ of A. mitchilli. Late summer (late July-August) remained relatively species rich and included mostly age 0+ of A. mitchilli, A. hepsetus, and M. menidia. Autumn (September-November) continued to have high catches of age 0+ of M. menidia and A. mitchilli. As expected for temperate estuaries, the best of the measured abiotic predictors of these groupings included temperature, salinity, and degree of change in temperature. However, timing of life history characteristics, such as location, and timing of reproduction and migration also influenced the seasonal occurrence of these pelagic species. The large abundance and biomass of a relatively few species, as observed in this study, are typical of estuaries, although this is one of the few studies that have focused solely on the pelagic component of estuarine fish assemblages.

Vertical ecology of the pelagic ocean: classical patterns and new perspectives.

Science.gov (United States)

Sutton, T T

2013-12-01

Applications of acoustic and optical sensing and intensive, discrete-depth sampling, in concert with collaborative international research programmes, have substantially advanced knowledge of pelagic ecosystems in the 17 years since the 1996 Deepwater Fishes Symposium of the Fisheries Society of the British Isles. Although the epipelagic habitat is the best-known, and remote sensing and high-resolution modelling allow near-synoptic investigation of upper layer biophysical dynamics, ecological studies within the mesopelagic and deep-demersal habitats have begun to link lower and upper trophic level processes. Bathypelagic taxonomic inventories are far from complete, but recent projects (e.g. MAR-ECO and CMarZ, supported by the Census of Marine Life programme) have quantitatively strengthened distribution patterns previously described for fishes and have provided new perspectives. Synthesis of net and acoustic studies suggests that the biomass of deep-pelagic fishes may be two to three orders of magnitude greater than the total global commercial fisheries landings. Discrete-depth net sampling has revealed relatively high pelagic fish biomass below 1000 m in some regions, and that gelatinous zooplankton may be key energy vectors for deep-pelagic fish production. Lastly, perhaps, the most substantive paradigm shift is that vertical connectivity among fishes across classical depth zones is prevalent- suggesting that a whole-water column approach is warranted for deep ocean conservation and management. © 2013 The Fisheries Society of the British Isles.

A high resolution magnetostratigraphic profile across the Permian-Triassic boundary in the Southern Sydney Basin, eastern Australia

Science.gov (United States)

Belica, M. E.; Tohver, E.; Nicoll, R.; Denyszyn, S. W.; Pisarevsky, S.; George, A. D.

2016-12-01

The Permian-Triassic boundary (PTB) is associated with the largest mass extinction in Phanerozoic geologic history. Despite several decades of intense study, there is ongoing debate regarding the exact timing of extinction and the global correlation of marine and terrestrial P-T sections. The terrestrial record is hampered by a lack of index fossils; however, magnetostratigraphy offers an opportunity for correlation because it relies on the global synchronicity of magnetic reversals. A magnetostratigraphic profile across the Permian-Triassic boundary has been obtained from a stratigraphically continuous terrestrial section in the Southern Sydney Basin of eastern Australia. The 60 m section is located within the Narrabeen Group, which consists of fluvial to lacustrine sandstones and mudstones. Paleomagnetic samples were collected at one meter intervals to determine a detailed reversal record. Samples were stepwise thermally demagnetized to isolate a primary remanence, and magnetic susceptibility was measured in the field at 30 cm intervals with values ranging from -0.047-2.50 (10-3 SI units). Three normal and three reverse magnetozones were detected after removal of a low temperature overprint, and the results show good agreement with the Global Magnetic Polarity Timescale as well as marine Permian-Triassic sections where the PTB is well constrained. Furthermore, a reverse polarity subchron has been identified within the normal magnetozone spanning the PTB similar to results published from the Netherlands and China. The magnetic stratigraphy suggests that the Narrabeen Group was deposited during the late Changhsingian to early Induan, and provides a revised placement of the PTB in the lower Wombarra Claystone. Integration of the magnetostratigraphy with existing isotopic datasets suggests that the terrestrial extinction in eastern Australia occurred 7.5 m below the PTB in the Changhsingian Coalcliff Sandstone. A tuff within a coal seam underlying the Coalcliff

2014 Small Pelagics Survey (GU1406, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the 2013 Small Pelagics Acoustic/Trawl Survey were to sample the northern Gulf of Mexico with a 90-ft high opening trawl to facilitate assessments of...

Food-web inferences of stable isotope spatial patterns in copepods and yellowfin tuna in the pelagic eastern Pacific Ocean

Science.gov (United States)

Olson, Robert J.; Popp, Brian N.; Graham, Brittany S.; López-Ibarra, Gladis A.; Galván-Magaña, Felipe; Lennert-Cody, Cleridy E.; Bocanegra-Castillo, Noemi; Wallsgrove, Natalie J.; Gier, Elizabeth; Alatorre-Ramírez, Vanessa; Ballance, Lisa T.; Fry, Brian

2010-07-01

Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and yellowfin tuna ( Thunnus albacares), and to quantify yellowfin tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ 15N values of several omnivorous copepod species, we examined isotopic spatial relationships among yellowfin tuna and copepods. We found a broad-scale, uniform gradient in δ 15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ 15N values in the white muscle of yellowfin tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ 15N values at the base of the food web, the isotopic difference between these two taxa, “ ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin tuna trophic-position estimates based on their bulk δ 15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore-offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin tuna stomach contents did not show a regular inshore-offshore gradient in trophic position during 2003-2005, but the trophic

Abundance and tidal behaviour of pelagic fish in the gateway to the Wadden Sea

NARCIS (Netherlands)

Couperus, B.; Gastauer, S.; Fässler, S.M.M.; Tulp, I.; van der Veer, H.W.; Poos, J.J.

2016-01-01

The shallow coast of The Netherlands is an important habitat for small pelagic fish. They form one of the major links between plankton and the higher trophic levels. Predatory fish, sea mammals and birds rely on small pelagic fish as a major food source. Currently, monitoring of fish in the Dutch

Identification and chemical studies of pelagic masses of Sargassum ...

African Journals Online (AJOL)

The pelagic seaweed found offshore and negatively impacting fishing activity in ... the mixed Sargassum species were analyzed for the proximate composition, ... Keywords: Sargassum natans, Sargassum fluitans, brown algae, proximate ...

Stratigraphy, plankton communities, and magnetic proxies at the Jurassic/Cretaceous boundary in the Pieniny Klippen Belt (Western Carpathians, Slovakia)

Czech Academy of Sciences Publication Activity Database

Michalík, J.; Reháková, D.; Grabowski, J.; Lintnerová, O.; Svobodová, Andrea; Schlögl, J.; Sobien, K.; Schnabl, Petr

2016-01-01

Roč. 67, č. 4 (2016), s. 303-328 ISSN 1335-0552 R&D Projects: GA ČR(CZ) GA16-09979S Institutional support: RVO:67985831 Keywords : J/K boundary * pelagic limestones * microfauna * nannoplankton * stable C and O isotopes * magnetic susceptibility * northern Tethys Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.358, year: 2016

76 FR 52888 - Western Pacific Pelagic Fisheries; American Samoa Longline Gear Modifications To Reduce Turtle...

Science.gov (United States)

2011-08-24

... Modifications To Reduce Turtle Interactions AGENCY: National Marine Fisheries Service (NMFS), National Oceanic... Pacific Region (Pelagics FEP), including an environmental assessment, that presents background information on this rule. The Pelagics FEP and Amendment 5 are available from the Council, 1164 Bishop St., Suite...

Abundance and tidal behaviour of pelagic fish in the gateway to the Wadden Sea

NARCIS (Netherlands)

Couperus, Bram; Gastauer, Sven; Fässler, Sascha M.M.; Tulp, Ingrid; Veer, van der Henk W.; Poos, Jan Jaap

2016-01-01

The shallow coast of The Netherlands is an important habitat for small pelagic fish. They form one of the major links between plankton and the higher trophic levels. Predatory fish, sea mammals and birds rely on small pelagic fish as a major food source. Currently, monitoring of fish in the Dutch

78 FR 9729 - Eastern States: Filing of Plat of Survey, North Carolina

Science.gov (United States)

2013-02-11

... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLES956000-L14200000-BJ0000] Eastern States..., on pages 318 through 319 a notice entitled ``Eastern States: Filing of Plats of Survey''. In said... Boundary, lands held in trust for the Eastern Band of Cherokee Indians, Swain County, in the State of North...

Distribution of pelagic harpacticoid copepods from the Indian ocean

Digital Repository Service at National Institute of Oceanography (India)

Haridas, P.; Rao, T.S.S.

Pelagic harpacticoid copepods have been studied from the International Indian Ocean Expedition collections. Macrosetella gracilis and Miracia efferata were the most common species of harpacticoids with high densities near land masses. Other three...

Warming shelf seas drive the subtropicalization of European pelagic fish communities.

Science.gov (United States)

Montero-Serra, Ignasi; Edwards, Martin; Genner, Martin J

2015-01-01

Pelagic fishes are among the most ecologically and economically important fish species in European seas. In principle, these pelagic fishes have potential to demonstrate rapid abundance and distribution shifts in response to climatic variability due to their high adult motility, planktonic larval stages, and low dependence on benthic habitat for food or shelter during their life histories. Here, we provide evidence of substantial climate-driven changes to the structure of pelagic fish communities in European shelf seas. We investigated the patterns of species-level change using catch records from 57,870 fisheries-independent survey trawls from across European continental shelf region between 1965 and 2012. We analysed changes in the distribution and rate of occurrence of the six most common species, and observed a strong subtropicalization of the North Sea and Baltic Sea assemblages. These areas have shifted away from cold-water assemblages typically characterized by Atlantic herring and European sprat from the 1960s to 1980s, to warmer-water assemblages including Atlantic mackerel, Atlantic horse mackerel, European pilchard and European anchovy from the 1990s onwards. We next investigated if warming sea temperatures have forced these changes using temporally comprehensive data from the North Sea region. Our models indicated the primary driver of change in these species has been sea surface temperatures in all cases. Together, these analyses highlight how individual species responses have combined to result in a dramatic subtropicalization of the pelagic fish assemblage of the European continental shelf. © 2014 John Wiley & Sons Ltd.

Is tuberculosis crossing borders at the Eastern boundary of the European Union?

Science.gov (United States)

van der Werf, Marieke J.; Hollo, Vahur; Noori, Teymur

2013-01-01

Background: The Eastern border of the European Union (EU) consists of 10 countries after the expansion of the EU in 2004 and 2007. These 10 countries border to the East to countries with high tuberculosis (TB) notification rates. We analyzed the notification data of Europe to quantify the impact of cross-border TB at the Eastern border of the EU. Methods: We used TB surveillance data of 2010 submitted by 53 European Region countries to the European Centre for Disease Prevention and Control and the World Health Organization Regional Office for Europe. Notified TB cases were stratified by origin of the case (national/foreign). We calculated the contribution of foreign to overall TB notification. Results: In the 10 EU countries located at the EU Eastern border, 618 notified TB cases (1.7% of all notified TB cases) were of foreign origin. Of those 618 TB cases, 173 (28.0%) were from countries bordering the EU to the East. More specifically, 90 (52.0%) were from Russia, 33 (19.1%) from Belarus, 33 (19.1%) from Ukraine, 13 (7.5%) from Moldova and 4 (2.3%) from Turkey. Conclusions: Currently, migrants contribute little to TB notifications in the 10 EU countries at the Eastern border of the EU, but changes in migration patterns may result in an increasing contribution. Therefore, EU countries at the Eastern border of the EU should strive to provide prompt diagnostic services and adequate treatment of migrants. PMID:23813718

Population regulation and role of mesozooplankton in shaping marine pelagic food webs

DEFF Research Database (Denmark)

Kiørboe, Thomas

1998-01-01

Copepods constitute the majority of the mesozooplankton in the oceans. By eating and being eaten copepods have implications for the flow of matter and energy in the pelagic environment. I first consider population regulation mechanisms in copepods by briefly reviewing estimates of growth and mort...... activity for plankton food webs, particularly their role in retarding vertical fluxes and, thus, the loss of material from the euphotic zone......Copepods constitute the majority of the mesozooplankton in the oceans. By eating and being eaten copepods have implications for the flow of matter and energy in the pelagic environment. I first consider population regulation mechanisms in copepods by briefly reviewing estimates of growth...... to variations in fecundity. This is consistent with the observed tremendous variation in copepod fecundity rates, relatively low and constant mortality rates and with morphological and behavioral characteristics of pelagic copepods (e.g., predator perception and escape capability, vertical migration), which can...

Assessment of the pelagic fish populations using CEN multi-mesh gillnets: consequences for the characterization of the fish communities

Directory of Open Access Journals (Sweden)

C. Deceliere-Vergès

2008-01-01

Full Text Available The contribution of CEN standard pelagic nets to the assessment of fish communities is tested by comparing three metrics (species composition, species abundance, and size structures measured in accordance with the standard (i.e. using benthic nets only to those calculated from the total effort (i.e. including pelagic nets. Hydroacoustic surveys were used simultaneously to assess fish densities in the pelagic habitat. The results show that in most cases the pelagic nets did not provide any extra information about these three metrics. However, their inclusion in the calculation of CPUE and size structures may affect the picture of the fish communities, especially in lakes containing salmonid populations. This study highlights the need to sample pelagic fish when assessing fish communities in order to determine lake quality.

Life cycle ecophysiology of small pelagic fish and climate-driven changes in populations

Science.gov (United States)

Peck, Myron A.; Reglero, Patricia; Takahashi, Motomitsu; Catalán, Ignacio A.

2013-09-01

Due to their population characteristics and trophodynamic role, small pelagic fishes are excellent bio-indicators of climate-driven changes in marine systems world-wide. We argue that making robust projections of future changes in the productivity and distribution of small pelagics will require a cause-and-effect understanding of historical changes based upon physiological principles. Here, we reviewed the ecophysiology of small pelagic (clupeiform) fishes including a matrix of abiotic and biotic extrinsic factors (e.g., temperature, salinity, light, and prey characteristics) and stage-specific vital rates: (1) adult spawning, (2) survival and development of eggs and yolk sac larvae, and (3) feeding and growth of larvae, post-larvae and juveniles. Emphasis was placed on species inhabiting Northwest Pacific and Northeast Atlantic (European) waters for which summary papers are particularly scarce compared to anchovy and sardine in upwelling systems. Our review revealed that thermal niches (optimal and sub-optimal ranges in temperatures) were species- and stage-specific but that temperature effects only partly explained observed changes in the distribution and/or productivity of populations in the Northwest Pacific and Northeast Atlantic; changes in temperature may be necessary but not sufficient to induce population-level shifts. Prey availability during the late larval and early juvenile period was a common, density-dependent mechanism linked to fluctuations in populations but recruitment mechanisms were system-specific suggesting that generalizations of climate drivers across systems should be avoided. We identified gaps in knowledge regarding basic elements of the growth physiology of each life stage that will require additional field and laboratory study. Avenues of research are recommended that will aid the development of models that provide more robust, physiological-based projections of the population dynamics of these and other small pelagic fish. In our

Contrasting the surface ocean distribution of bromoform and methyl iodide; implications for boundary layer physics, chemistry and climate

Energy Technology Data Exchange (ETDEWEB)

Palmer, C J, E-mail: carl.j.palmer@gmail.co [Department of Oceanography, University of Cape Town, 7701 (South Africa)

2010-08-15

Bromoform and methyl iodide are both methane-like hydrocarbons with a halogen atom replacing one or more of the hydrogen atoms. Both of these compounds occur naturally in the environment as a result of their production from seaweed and kelp. They are of interest to climate science as a result of their catalytic destruction of boundary layer ozone (a potent greenhouse gas) and, specifically for methyl iodide, the proposed role in the formation of new cloud condensation nuclei with implications for climate. In this paper, the currently available data on the distribution of bromoform and methyl iodide are analysed and contrasted to show that the concentrations of bromoform and methyl iodide do not correlate, that, in contrast to bromoform, the parameterization of sea surface methyl iodide concentrations demands only the sea surface temperature, and that the pelagic distribution of methyl iodide appears to follow the solar zenith angle. These three observations together suggest that, while the pelagic source of bromoform is mostly biogenic, the source of methyl iodide is photochemical. This has implications for the understanding of planetary boundary layer chemistry and potential organohalogen mediated feedbacks to climate.

Contrasting the surface ocean distribution of bromoform and methyl iodide; implications for boundary layer physics, chemistry and climate

International Nuclear Information System (INIS)

Palmer, C J

2010-01-01

Bromoform and methyl iodide are both methane-like hydrocarbons with a halogen atom replacing one or more of the hydrogen atoms. Both of these compounds occur naturally in the environment as a result of their production from seaweed and kelp. They are of interest to climate science as a result of their catalytic destruction of boundary layer ozone (a potent greenhouse gas) and, specifically for methyl iodide, the proposed role in the formation of new cloud condensation nuclei with implications for climate. In this paper, the currently available data on the distribution of bromoform and methyl iodide are analysed and contrasted to show that the concentrations of bromoform and methyl iodide do not correlate, that, in contrast to bromoform, the parameterization of sea surface methyl iodide concentrations demands only the sea surface temperature, and that the pelagic distribution of methyl iodide appears to follow the solar zenith angle. These three observations together suggest that, while the pelagic source of bromoform is mostly biogenic, the source of methyl iodide is photochemical. This has implications for the understanding of planetary boundary layer chemistry and potential organohalogen mediated feedbacks to climate.

77 FR 34334 - Western Pacific Pelagic Fisheries; Revised Limits on Sea Turtle Interactions in the Hawaii...

Science.gov (United States)

2012-06-11

... Interactions in the Hawaii Shallow-Set Longline Fishery AGENCY: National Marine Fisheries Service (NMFS... occur between the Hawaii-based shallow-set pelagic longline fishery and leatherback and loggerhead sea... Fisheries, NMFS PIR, 808-944-2248. SUPPLEMENTARY INFORMATION: The Hawaii-based shallow-set pelagic longline...

Fall 2011 Small Pelagics Survey (PC1108, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the Fall 2011 Small Pelagics Survey were to sample the waters of the northern Gulf of Mexico less than 500 meters deep with 90-ft high opening fish...

Fall 2010 Small Pelagics Survey (PC1006, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Objectives of the Fall 2010 Small Pelagics Survey were to sample the waters of the northern Gulf of Mexico less than 500 meters deep with 90-ft high opening fish...

Using Genome-Wide SNPs to Detect Structure in High-Diversity and Low-Divergence Populations of Severely Impacted Eastern Tropical Pacific Spinner (Stenella longirostris And Pantropical Spotted Dolphins (S. attenuata

Directory of Open Access Journals (Sweden)

Matthew Steven Leslie

2016-12-01

Full Text Available Millions of spinner (Stenella longirostris and pantropical spotted dolphins (Stenella attenuata died since the 1960’s as bycatch in tuna nets in the eastern tropical Pacific Ocean. Despite three decades of protection, they show little-to-no sign of recovery (although recent fisheries-independent abundance estimates are not available. In efforts to establish biologically meaningful management boundaries for recovery, endemic subspecies and multiple stocks have been proposed. However, genetic differentiation among most of these units has been difficult to identify, possibly due to low statistical power stemming from large historical abundances, ongoing gene flow, and recent divergence. We tested for genetic structure at multiple hierarchical levels by analyzing the largest dataset to date brought to bear on these questions. Single nucleotide polymorphisms (SNPs were collected from nuclear DNA regions associated with the restriction enzyme site PstI from 72 spinner dolphins and 58 pantropical spotted dolphins using genotype-by-sequencing (GBS. Our results support the current subspecies for both species and indicate stock-level separation for Tres Marias spinner dolphins and the two offshore pantropical spotted dolphin stocks in this area. Although bycatch has been reduced a small fraction of pre-protection levels, incidental mortality continues to impact these populations. Our results are important for the ongoing management and recovery of these highly-impacted pelagic dolphins in the eastern tropical Pacific Ocean.

The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world

DEFF Research Database (Denmark)

Griffiths, Jennifer R.; Kadin, Martina; Nascimento, Francisco J. A.

2017-01-01

and function is strongly affected by anthropogenic pressures, however there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling...... processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study, and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic......Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure...

The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world.

Science.gov (United States)

Griffiths, Jennifer R; Kadin, Martina; Nascimento, Francisco J A; Tamelander, Tobias; Törnroos, Anna; Bonaglia, Stefano; Bonsdorff, Erik; Brüchert, Volker; Gårdmark, Anna; Järnström, Marie; Kotta, Jonne; Lindegren, Martin; Nordström, Marie C; Norkko, Alf; Olsson, Jens; Weigel, Benjamin; Žydelis, Ramunas; Blenckner, Thorsten; Niiranen, Susa; Winder, Monika

2017-06-01

Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems, and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure and function are strongly affected by anthropogenic pressures; however, there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic-pelagic coupling processes (e.g., nutrient exchange and sedimentation of organic material) are to some extent quantifiable, but the magnitude and variability of biological processes are rarely assessed, preventing quantitative comparisons. Changing oxygen conditions will continue to have widespread effects on the processes that govern inorganic and organic matter exchange among habitats while climate change and nutrient load reductions may have large effects on organic matter sedimentation. Many biological processes (predation, bioturbation) are expected to be sensitive to anthropogenic drivers, but the outcomes for ecosystem function are largely unknown. We emphasize how improved empirical and experimental understanding of benthic-pelagic coupling processes and their variability are necessary to inform models that can quantify the feedbacks among processes and ecosystem responses to a changing world. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

A mathematical model of algae growth in a pelagic-benthic coupled shallow aquatic ecosystem.

Science.gov (United States)

Zhang, Jimin; Shi, Junping; Chang, Xiaoyuan

2018-04-01

A coupled system of ordinary differential equations and partial differential equations is proposed to describe the interaction of pelagic algae, benthic algae and one essential nutrient in an oligotrophic shallow aquatic ecosystem with ample supply of light. The existence and uniqueness of non-negative steady states are completely determined for all possible parameter range, and these results characterize sharp threshold conditions for the regime shift from extinction to coexistence of pelagic and benthic algae. The influence of environmental parameters on algal biomass density is also considered, which is an important indicator of algal blooms. Our studies suggest that the nutrient recycling from loss of algal biomass may be an important factor in the algal blooms process; and the presence of benthic algae may limit the pelagic algal biomass density as they consume common resources even if the sediment nutrient level is high.

Quantifying pelagic-benthic coupling in the North Sea: Are we asking the right question?

DEFF Research Database (Denmark)

Richardson, K.; Cedhagen, T.

2002-01-01

is devoted to obtaining more and better data describing this exchange. Efforts to quantify exchange between the water column and the sediment must continue. However, such studies will not, in themselves, lead to a quantification of pelagic-benthic coupling in the North Sea. We identify here other areas......The coupling between pelagic and benthic processes occurs through the signals sent between the water column and the seabed. Huge methodological challenges are associated with the quantification of the signals being sent between these two domains - especially in a relatively shallow and heavily...... fished region such as the North Sea where deployment of sediment traps or bottom mounted cameras or samplers is difficult. Thus, there are relatively few sites in the North Sea for which good data are available for describing pelagic-benthic (or near shore-offsbore) coupling and considerable effort...

87Sr/86Sr variations in basalts of Late Eocene-Early Miocene series in Eastern Sikhoteh-Alin

International Nuclear Information System (INIS)

Esin, S.V.; Ponomarchuk, V.A.; Shipitsyn, Yu.G.; Palesskij, Yu.G.

1993-01-01

Late Eocene high-alumina and Oligocene high-alumina and magnesian basalts of the Neogene calc-alkaline series from the Eastern Sikhoteh-Alin are shown to have the following 87 Sr/ 86 Sr ratios: 0.70390-0.70465; 0.70347-0.70401, and the 0.70330-0.70347. Analysis of variations of Sr ratios, REE, HFSE, and LILE suggests that they are the products of successive melting of a multicomponent source containing the peridotite material of OIB- and MORB-types altered by fluids to a different degree and the pelagic sediments

Why is relating plankton community structure to pelagic production ...

African Journals Online (AJOL)

mixing regulates primary production, and assuming certain features of food-chain length and efficiency, one can estimate fish yields. Fundamental to these arguments are assumptions concerning resource limitation which appear to be uncertain as generic marine pelagic characteristics, primarily that trophic levels are ...

[Effects of submarine topography and water depth on distribution of pelagic fish community in minnan-taiwan bank fishing ground].

Science.gov (United States)

Fang, Shuimei; Yang, Shengyun; Zhang, Chengmao; Zhu, Jinfu

2002-11-01

According to the fishing record of the light-seine information vessel in Minnan-Taiwan bank ground during 1989 to 1999, the effects of submarine topography and water depth on distribution of pelagic fish community in Minnan-Taiwan bank fishing ground was studied. The results showed that the pelagic fish distributed concentratively, while the submarine topography and water depth varied widely, but in different fishing regions, the distribution of pelagic fishes was uneven. The distribution of fishing yield increased from north to south, and closed up from sides of the bank to south or north in the regions. Pelagic fish distributed mainly in mixed water in the southern Taiwan Strait, and in warm water in the Taiwan Strait. The central fishing grounds were at high salt regions. Close gathering regions of pelagic fish or central fishing ground would be varied with the seasonal variation of mixed water in the southern Taiwan Strait and warm water in the Taiwan Strait. Central fishing ground was not only related to submarine topography and water depth, but also related to wind direction, wind-power and various water systems. In the fishing ground, the gathering depth of pelagic fish was 30-60 m in spring and summer, and 40-80 m in autumn and winter.

76 FR 33189 - Fisheries Off West Coast States; Coastal Pelagic Species Fisheries; Amendment 13 to the Coastal...

Science.gov (United States)

2011-06-08

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 660 RIN 0648-BA68 Fisheries Off West Coast States; Coastal Pelagic Species Fisheries; Amendment 13 to the Coastal... Pacific Fishery Management Council (Council) has submitted Amendment 13 to the Coastal Pelagic Species...

Impacts of gold mine waste disposal on a tropical pelagic ecosystem

International Nuclear Information System (INIS)

Brewer, D.T.; Morello, E.B.; Griffiths, S.; Fry, G.; Heales, D.; Apte, S.C.; Venables, W.N.; Rothlisberg, P.C.; Moeseneder, C.; Lansdell, M.; Pendrey, R.; Coman, F.

2012-01-01

Highlights: ► We investigate the impact of gold mine tailings disposal into the sea. ► We use a comparative impact-control approach. ► Similar abundance and diversity of zooplankton and micronekton at mine and control. ► High metal concentrations and biomagnification evident in lower trophic levels only. ► No differences in metal concentrations of fish at mine and control. - Abstract: We used a comparative approach to investigate the impact of the disposal of gold mine tailings into the ocean near the Lihir mine (Niolam Island, Papua New Guinea). We found abundance and diversity of zooplankton, micronekton and pelagic fish to be similar or higher in the mine region compared to the reference site. We also found relatively high trace metal concentrations in lower trophic level groups, especially zooplankton, near the mine discharge, but few differences in tissue concentrations of micronekton, baitfish and pelagic fish between the two regions. Biomagnification of some trace metals by micronekton, and of mercury by fish was evident in both regions. We conclude that ocean mine waste disposal at Niolam Island has a local impact on the smaller and less mobile pelagic communities in terms of trace metal concentrations, but has little effect on the abundance and biodiversity of the local food web.

Organic carbon budget for the eastern boundary of the North Atlantic subtropical gyre: major role of DOC in mesopelagic respiration.

Science.gov (United States)

Santana-Falcón, Yeray; Álvarez-Salgado, Xosé Antón; Pérez-Hernández, María Dolores; Hernández-Guerra, Alonso; Mason, Evan; Arístegui, Javier

2017-08-31

Transports of suspended particulate (POC susp ) and dissolved (DOC) organic carbon are inferred from a box-model covering the eastern boundary of the North Atlantic subtropical gyre. Corresponding net respiration rates (R) are obtained from a net organic carbon budget that is based on the transport estimates, and includes both vertical and lateral fluxes. The overall R in the mesopelagic layer (100-1500 m) is 1.6 ± 0.4 mmol C m -2 d -1 . DOC accounts for up to 53% of R as a result of drawdown of organic carbon within Eastern North Atlantic Central Water (ENACW) that is entrained into sinking Mediterranean Overflow Water (MOW) that leads to formation of Mediterranean water (MW) at intermediate depths (~900 m). DOC represents 90% of the respired non-sinking organic carbon. When converted into oxygen units, the computed net respiration rate represents less than half the oxygen utilization rates (OUR) reported for the mesopelagic waters of the subtropical North Atlantic. Mesoscale processes in the area, not quantified with our approach, could account in part for the OUR differences observed between our carbon budget and other published studies from the North Atlantic, although seasonal or interannual variability could also be responsible for the difference in the estimates.

77 FR 50388 - Coastal Migratory Pelagic Resources of the Gulf of Mexico and South Atlantic; 2012-2013...

Science.gov (United States)

2012-08-21

... Brownsville, Texas) and continues to the boundary between the eastern and western zones at 87[deg]31.1[min] W... Atlantic; 2012-2013 Accountability Measure and Closure for Gulf King Mackerel in Western Zone AGENCY... king mackerel in the western zone of the Gulf of Mexico (Gulf) exclusive economic zone (EEZ) through...

Feeding ecology of pelagic fish larvae and juveniles in slope waters of the Gulf of Mexico.

Science.gov (United States)

Wells, R J D; Rooker, J R

2009-11-01

Stable isotope ratios of carbon (delta13C) and nitrogen (delta15N) were used to investigate feeding patterns of larval and early juvenile pelagic fishes in slope waters of the Gulf of Mexico. Contribution of organic matter supplied to fishes and trophic position within this pelagic food web was estimated in 2007 and 2008 by comparing dietary signatures of the two main producers in this ecosystem: phytoplankton [based on particulate organic matter (POM)] and Sargassum spp. Stable isotope ratios of POM and pelagic Sargassum spp. were significantly different from one another with delta13C values of POM depleted by 3-6 per thousand and delta15N values enriched by 2 relative to Sargassum spp. Stable isotope ratios were significantly different among the five pelagic fishes examined: blue marlin Makaira nigricans, dolphinfish Coryphaena hippurus, pompano dolphinfish Coryphaena equiselis, sailfish Istiophorus platypterus and swordfish Xiphias gladius. Mean delta13C values ranged almost 2 among fishes and were most depleted in I. platypterus. In addition, mean delta15N values ranged 4-5 with highest mean values found for both C. hippurus and C. equiselis and the lowest mean value for M. nigricans during both years. Increasing delta13C or delta15N with standard length suggested that shifts in trophic position and diet occurred during early life for several species examined. Results of a two-source mixing model suggest approximately an equal contribution of organic matter by both sources (POM=55%; pelagic Sargassum spp.=45%) to the early life stages of pelagic fishes examined. Contribution of organic matter, however, varied among species, and sensitivity analyses indicated that organic source estimates changed from 2 to 13% for a delta(13)C fractionation change of +/-0.25 per thousand or a delta15N fractionation change of +/-1.0 per thousand relative to original fractionation values.

Thirty novel microsatellite markers for the coastal pelagic fish ...

Indian Academy of Sciences (India)

Scomber japonicus (Scombridae: Scomber) is a wide-spread pelagic fish in the warm and temperate transition coastal areas and adjacent seas of Atlantic, Pacific and northwest. Indian oceans (Collette and Nauen 1983). Although there are few studies on development of microsatellite markers that provide useful tool to ...

Subsurface phytoplankton blooms fuel pelagic production in the North Sea

DEFF Research Database (Denmark)

Richardson, Kathrine; Visser, Andre; Pedersen, Flemming

2000-01-01

The seasonal phytoplankton biomass distribution pattern in stratified temperate marine waters is traditionally depicted as consisting of spring and autumn blooms. The energy source supporting pelagic summer production is believed to be the spring bloom. However, the spring bloom disappears...... relatively quickly from the water column and a large proportion of the material sedimenting to the bottom following the spring bloom is often comprised of intact phytoplankton cells. Thus, it is easy to argue that the spring bloom is fueling the energy demands of the benthos, but more difficult to argue...... convincingly that energy fixed during the spring bloom is fueling the pelagic production occurring during summer months. We argue here that periodic phytoplankton blooms are occurring during the summer in the North Sea at depths of >25 m and that the accumulated new production [sensu (Dugdale and Goering...

Evolution of the Sauropterygian Labyrinth with Increasingly Pelagic Lifestyles.

Science.gov (United States)

Neenan, James M; Reich, Tobias; Evers, Serjoscha W; Druckenmiller, Patrick S; Voeten, Dennis F A E; Choiniere, Jonah N; Barrett, Paul M; Pierce, Stephanie E; Benson, Roger B J

2017-12-18

Sauropterygia, a successful clade of marine reptiles abundant in aquatic ecosystems of the Mesozoic, inhabited nearshore to pelagic habitats over >180 million years of evolutionary history [1]. Aquatic vertebrates experience strong buoyancy forces that allow movement in a three-dimensional environment, resulting in structural convergences such as flippers and fish-like bauplans [2, 3], as well as convergences in the sensory systems. We used computed tomographic scans of 19 sauropterygian species to determine how the transition to pelagic lifestyles influenced the evolution of the endosseous labyrinth, which houses the vestibular sensory organ of balance and orientation [4]. Semicircular canal geometries underwent distinct changes during the transition from nearshore Triassic sauropterygians to the later, pelagic plesiosaurs. Triassic sauropterygians have dorsoventrally compact, anteroposteriorly elongate labyrinths, resembling those of crocodylians. In contrast, plesiosaurs have compact, bulbous labyrinths, sharing some features with those of sea turtles. Differences in relative labyrinth size among sauropterygians correspond to locomotory differences: bottom-walking [5, 6] placodonts have proportionally larger labyrinths than actively swimming taxa (i.e., all other sauropterygians). Furthermore, independent evolutionary origins of short-necked, large-headed "pliosauromorph" body proportions among plesiosaurs coincide with reductions of labyrinth size, paralleling the evolutionary history of cetaceans [7]. Sauropterygian labyrinth evolution is therefore correlated closely with both locomotory style and body proportions, and these changes are consistent with isolated observations made previously in other marine tetrapods. Our study presents the first virtual reconstructions of plesiosaur endosseous labyrinths and the first large-scale, quantitative study detailing the effects of increasingly aquatic lifestyles on labyrinth morphology among marine reptiles. Copyright

Temperature Reconstruction and Biomarker Variation across the Cretaceous-Paleogene Boundary, Mid-Waipara River, New Zealand

Science.gov (United States)

Taylor, K. W.; Hollis, C. J.; Pancost, R. D.

2010-12-01

, indicative of cool-temperate conditions. Preliminary biostratigraphic correlation suggests that this interval is condensed, possibly truncated at the base, and may be correlated to a more expanded biogenic silica-rich interval in the pelagic K/Pg boundary sections in eastern Marlborough, northeastern South Island. These results support siliceous microfossil evidence for pronounced cooling in early Paleocene in New Zealand. Organic biomarker records provide further insight into terrestrial and marine ecological reconfiguration through the K/Pg boundary transition at Mid-Waipara River. Major reorganisations of the phytoplankton and archaeal communities are indicated by pronounced changes in sterol and tetraether distributions following the K/Pg boundary. Transient disruption of higher plants at the boundary is verified by suppression of n-alkane and triterpenoid biomarker concentrations, succeeded by a gradual recovery into the Early Paleocene. The scenario envisaged may be summarised as climate instability following the K/Pg boundary event, culminating in cool climatic conditions and a strengthened local upwelling regime leading to widespread deposition of diatom-rich siliceous sediments, lasting for around 1 Myr.

Global change: Ecology of Greenlandish and Siberian shelf areas

International Nuclear Information System (INIS)

1993-01-01

This work aimed to study the distribution and structure of pelagic and benthal biocoenoses in two areas, the continental shelf of eastern Greenland and the northern Barents Sea, and to compare them in relation to their ecological boundary conditions. Furthermore, aspects of ontogenetic and ecophysiological adaptations of key species were investigated. The programme followed a fourfold approach: 1) Inventory of fauna, 2) analysis of the distribution and composition of communities, 3) autecological studies of selected key species, 4) description of associations between community structures, autecological adaptations, and special environmental conditions. In this way an inventory of pelagic and benthal biocoenoses in the two areas of investigation was prepared also with a view to further studies. Different modern sampling and data acquisition methods were used to ensure covering a broad spectrum of forms and sizes of fauna. (orig./KW) [de

Townet database - Evaluating the ecological health of Puget Sound's pelagic foodweb

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — To evaluate effects of human influence on the health of Puget Sound's pelagic ecosystems, we propose a sampling program across multiple oceanographic basins...

Spatial distribution and offshore export of total organic carbon along the eastern boundary of the Subtropical North Pacific

Directory of Open Access Journals (Sweden)

C.G. Castro

2011-12-01

Full Text Available Data collected in February, 2003, along the upper continental slope of western North America between Monterey Bay, California (37°N, 122°W, and Cabo San Lucas, Mexico (23°N, 118°W, document, for the first time, the alongshore distribution of total organic carbon (TOC. Highest TOC concentrations (>70 µM were observed for waters above the nitracline and associated with both California Current and southern surface waters. The northward advection of tropical waters in the California Undercurrent did not have any discernible impact on TOC distributions. An estimate of the average rate at which TOC in surface waters was exported offshore by Ekman transport in February 2003 was 1.73 × 103 kg C yr−1 for each meter of coastline. The offshore flux estimate is thought to be conservative with respect to the annual mean offshore flux because the offshore Ekman transport and primary production increase in late spring and early summer and the contribution of upwelling filaments has not been considered. Analysis of TOC contributions to pelagic respiration suggested that TOC accounted for 45% of the oxygen decrease in southern oxic waters. In California Current and oxygen minimum zone waters, TOC did not contribute to pelagic respiration.

Ecological diversification associated with the benthic-to-pelagic transition by North American minnows.

Science.gov (United States)

Burress, E D; Holcomb, J M; Tan, M; Armbruster, J W

2017-03-01

Ecological opportunity is often regarded as a key factor that explains why diversity is unevenly distributed across life. Colonization of novel environments or adaptive zones may promote diversification. North American minnows exhibit an ancestral benthic-to-pelagic habitat shift that coincided with a burst in diversification. Here, we evaluate the phenotypic and ecological implications of this habitat shift by assessing craniofacial and dietary traits among 34 species and testing for morphology-diet covariation, convergence and adaptive optima. There were several instances of morphology-diet covariation such as correlations between mouth angle and the consumption of terrestrial insects and between relative gut length and the consumption of algae. After accounting for size and phylogenetic nonindependence, benthic species had longer heads, longer snouts, eyes positioned higher on their head, smaller mouth angles and longer digestive tracts than pelagic minnows. Benthic minnows also consumed more algae but less terrestrial insects, by volume, than pelagic minnows. Lastly, there were three distinct evolutionary regimes and more convergence in morphology and dietary characteristics than expected under a Brownian motion model of evolution. These findings indicate that colonization of the pelagic zone by minnows involved myriad phenotypic and dietary changes associated with exploitation of terrestrial subsidies. Thus, minnows exhibit phenotype-dietary covariation, an expansion of ecological roles and a burst in diversification rates in response to the ecological opportunity afforded by the colonization of a novel habitat. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Assessing the state of pelagic fish communities within an ecosystem approach and the European Marine Strategy Framework Directive

DEFF Research Database (Denmark)

Shephard, Samuel; Rindorf, Anna; Dickey-Collas, Mark

2014-01-01

Pelagic fish are key elements in marine foodwebs and thus comprise an important part of overall ecosystem health. We develop a suite of ecological indicators that track pelagic fish community state and evaluate state of specific objectives against Good Environmental Status (GES) criteria. Indicator...

78 FR 64888 - Coastal Migratory Pelagic Resources of the Gulf of Mexico and South Atlantic; Reopening of the...

Science.gov (United States)

2013-10-30

... the boundary between the eastern and western zones at 87[deg]31.1' W. long., which is a line directly... Atlantic; Reopening of the Commercial Harvest of Gulf King Mackerel in Western Zone AGENCY: National Marine... western zone of the Gulf of Mexico (Gulf) exclusive economic zone (EEZ). NMFS previously projected that...

Total primary production and the balance between benthic and pelagic plants in different nutrient regimes in a shallow estuary

DEFF Research Database (Denmark)

Markager, Svend Stiig; Krause-Jensen, Dorte; Dalsgaard, Tage

on a large monitoring data set in combination with historical information we have quantified and compared the benthic and the pelagic primary production along nutrient gradients in space and time for the shallow estuary Limfjorden, Denmark. As expected, increases in nutrient load stimulated the pelagic...... was again reduced, and the ecosystem entered a phase of oligotrophication, pelagic GPP declined gradually while benthic GPP did not increase correspondingly leading to an decline in overall GPP. Instead the ecosystem showed a resistance or time lag against return to a clear water state with benthic...

Hexabromocyclododecane affects benthic-pelagic coupling in an experimental ecosystem

International Nuclear Information System (INIS)

Bradshaw, Clare; Näslund, Johan; Hansen, Joakim; Kozlowsky-Suzuki, Betina; Sundström, Bo; Gustafsson, Kerstin

2015-01-01

Hexabromocyclododecane (HBCDD) is an additive brominated flame retardant and a recognized PBT chemical. However, little is known about its effects on coastal species, and even less on ecosystem effects. We investigated the dose–response effects of HBCDD over 8 months in 1000 L experimental mesocosms assembled from coastal Baltic Sea ecosystem components. HBCDD was added via spiked plankton material and a range of structural and functional endpoints were measured during the experiment. Increasing HBCDD concentration decreased the biomass of large Macoma balthica, resulting in a decreased recirculation of nutrients to the water. Changes in plankton communities were also observed, either due to direct toxic HBCDD effects or indirect via changes in benthic-pelagic coupling of nutrients. Such complex ecosystem responses can only be quantified and understood by using realistic experimental set-ups, and including knowledge of system-specific ecological interactions. This is the first study of HBCDD effects on ecosystem level. - Graphical abstract: HBCDD caused direct effects on the population structure of sediment-dwelling Macoma balthica and on the plankton community. Indirect HBCDD effects via reduced nutrient remineralization by M. balthica affected nutrient levels in the water, likely leading to additional changes in plankton community structure. Seasonal effects were large and affected the whole system including nutrient dynamics as well as plankton community structure. Display Omitted - Highlights: • HBCDD caused effects on benthic population structure and ecosystem function. • Large seasonal effects highlight the importance of using relevant experimental conditions. • A realistic exposure pathway was applied by using HBCDD enriched plankton material. • This is the first study of HBCDD effects on ecosystem level, coupling benthic and pelagic communities. - HBCDD has a dose-dependent effect on benthic-pelagic coupling.

Planktonic stages of small pelagic fishes (Sardinella aurita and Engraulis encrasicolus) in the central Mediterranean Sea: The key role of physical forcings and implications for fisheries management

Science.gov (United States)

Torri, Marco; Corrado, Raffaele; Falcini, Federico; Cuttitta, Angela; Palatella, Luigi; Lacorata, Guglielmo; Patti, Bernardo; Arculeo, Marco; Mifsud, Roberta; Mazzola, Salvatore; Santoleri, Rosalia

2018-03-01

Multidisciplinary studies are recently aiming to define diagnostic tools for fishery sustainability by coupling ichthyoplanktonic datasets, physical and bio-geochemical oceanographic measurements, and ocean modelling. The main goal of these efforts is to understand those processes that control the dispersion and fate of fish larvae and eggs, and thus tuning the inter-annual variability of the biomass of small pelagic fish species. In this paper we analyse the distribution of eggs and larvae as well as the biological features of the two species of pelagic fish, Engraulis encrasicolus and Sardinella aurita in the north-eastern sector of the Sicily Channel (Mediterranean Sea) from ichthyoplanktonic data collected during the 2010 and 2011 summer cruises. We use Lagrangian simulations and satellite data (i.e., sea surface temperature, wind, and chlorophyll-a concentration) to recognize the main oceanographic patterns that mark eggs and larvae transport processes. We provide a mechanistic explanation of a cross-shore transport process by using a potential vorticity (PV) model that takes into account the role of wind stress in generating cold filaments. Our results show that the strong offshore transport towards Malta occurred in 2010 was likely due to a persistent Mistral wind forcing that generated high-PV cold filaments. This phenomenon was not found in the 2011 analysis, which indeed showed an along-shore transport towards the retention area of Capo Passero. Since, for the first time, we describe the spatial distribution of the early life stage of Sardinella aurita in the northern part of the Sicily Channel and we clarify the link between the ocean dynamics and the fate of small pelagic fish larvae, this work provides a useful, diagnostic tool for the sustainable management of fishery resources.

Impact of El Niño events on pelagic fisheries in Peruvian waters

Science.gov (United States)

Ñiquen, Miguel; Bouchon, Marilú

2004-03-01

Using data from stock assesment surveys on pelagic resources during El Niño events of 1972/73, 1982/83, 1997/98, we analyze biological changes on pelagic ecosystems and pelagic fisheries during different stages of development of El Niño phenomenon: emergence, full, final and post-Niño. Results indicate changes in spatial distribution of resources, their concentration and size structure. In anchovy (Engraulis ringens) a decrease in biomass was observed, which was estimated at 1.2 million tons in September 1998, the lowest throughout the 1990s. This resource showed an asymmetric distribution towards the south of Peru. Other pelagic resources increased their biomass during or after Niño events, primarily sardine (Sardinops sagax), jack mackerel (Trachurus murphyi), pacific mackerel (Scomber japonicus), and longnose anchovy (Anchoa nasus). At the end of the El Niño phenomenon we found less productivity but more diversity in the pelagic ecosystem. During the 1997/98 El Niño, the diversity index (Manual de Ecologia, 1a Edition, Editorial Trillas, Mexico, 267pp) increased from 0.87 to 1.23-1.70. In both the emergence stage and fully developed stages of El Niño we found large numbers of sardine and longnose anchovy present simultaneously. Size structure of sardine, jack mackerel, and pacific mackerel showed an increase in juveniles. Anchovy during El Niño showed a single modal group composed of adults, but the post-Niño phase indicated an increase in juveniles with an average length of 6-7 cm. In El Niño conditions spawning among anchovy was low, but among sardine and pacific mackerel it was high. We observed, for the first time during full spawning, juvenile sardines with a total length of 18-20 cm. The anchovy spawning season during the post-Niño phase was considerably lengthened, from April to December 1998. Drastic change occurred in fisheries when monospecific fisheries, based on anchovy before El Niño, became multispecific fisheries based on sardine, jack

Do pelagic grazers benefit from sea ice? Insights from the Antarctic sea ice proxy IPSO25

Directory of Open Access Journals (Sweden)

K. Schmidt

2018-04-01

Full Text Available Sea ice affects primary production in polar regions in multiple ways. It can dampen water column productivity by reducing light or nutrient supply, provide a habitat for ice algae and condition the marginal ice zone (MIZ for phytoplankton blooms on its seasonal retreat. The relative importance of three different carbon sources (sea ice derived, sea ice conditioned, non-sea-ice associated for the polar food web is not well understood, partly due to the lack of methods that enable their unambiguous distinction. Here we analysed two highly branched isoprenoid (HBI biomarkers to trace sea-ice-derived and sea-ice-conditioned carbon in Antarctic krill (Euphausia superba and relate their concentrations to the grazers' body reserves, growth and recruitment. During our sampling in January–February 2003, the proxy for sea ice diatoms (a di-unsaturated HBI termed IPSO25, δ13C  =  −12.5 ± 3.3 ‰ occurred in open waters of the western Scotia Sea, where seasonal ice retreat was slow. In suspended matter from surface waters, IPSO25 was present at a few stations close to the ice edge, but in krill the marker was widespread. Even at stations that had been ice-free for several weeks, IPSO25 was found in krill stomachs, suggesting that they gathered the ice-derived algae from below the upper mixed layer. Peak abundances of the proxy for MIZ diatoms (a tri-unsaturated HBI termed HBI III, δ13C  =  −42.2 ± 2.4 ‰ occurred in regions of fast sea ice retreat and persistent salinity-driven stratification in the eastern Scotia Sea. Krill sampled in the area defined by the ice edge bloom likewise contained high amounts of HBI III. As indicators for the grazer's performance we used the mass–length ratio, size of digestive gland and growth rate for krill, and recruitment for the biomass-dominant calanoid copepods Calanoides acutus and Calanus propinquus. These indices consistently point to blooms in the MIZ as an important feeding

Do pelagic grazers benefit from sea ice? Insights from the Antarctic sea ice proxy IPSO25

Science.gov (United States)

Schmidt, Katrin; Brown, Thomas A.; Belt, Simon T.; Ireland, Louise C.; Taylor, Kyle W. R.; Thorpe, Sally E.; Ward, Peter; Atkinson, Angus

2018-04-01

Sea ice affects primary production in polar regions in multiple ways. It can dampen water column productivity by reducing light or nutrient supply, provide a habitat for ice algae and condition the marginal ice zone (MIZ) for phytoplankton blooms on its seasonal retreat. The relative importance of three different carbon sources (sea ice derived, sea ice conditioned, non-sea-ice associated) for the polar food web is not well understood, partly due to the lack of methods that enable their unambiguous distinction. Here we analysed two highly branched isoprenoid (HBI) biomarkers to trace sea-ice-derived and sea-ice-conditioned carbon in Antarctic krill (Euphausia superba) and relate their concentrations to the grazers' body reserves, growth and recruitment. During our sampling in January-February 2003, the proxy for sea ice diatoms (a di-unsaturated HBI termed IPSO25, δ13C = -12.5 ± 3.3 ‰) occurred in open waters of the western Scotia Sea, where seasonal ice retreat was slow. In suspended matter from surface waters, IPSO25 was present at a few stations close to the ice edge, but in krill the marker was widespread. Even at stations that had been ice-free for several weeks, IPSO25 was found in krill stomachs, suggesting that they gathered the ice-derived algae from below the upper mixed layer. Peak abundances of the proxy for MIZ diatoms (a tri-unsaturated HBI termed HBI III, δ13C = -42.2 ± 2.4 ‰) occurred in regions of fast sea ice retreat and persistent salinity-driven stratification in the eastern Scotia Sea. Krill sampled in the area defined by the ice edge bloom likewise contained high amounts of HBI III. As indicators for the grazer's performance we used the mass-length ratio, size of digestive gland and growth rate for krill, and recruitment for the biomass-dominant calanoid copepods Calanoides acutus and Calanus propinquus. These indices consistently point to blooms in the MIZ as an important feeding ground for pelagic grazers. Even though ice

An Automated System for Incubation of Pelagic Fish Eggs

Directory of Open Access Journals (Sweden)

Leif Jørgensen

1987-01-01

Full Text Available An automated system for incubation of pelagic fish eggs is described. The system has an internal air driven water circulation which separates healthy and dead or strongly infected eggs. A processor controlled, pulsed water exchange provides a strongly reduced water requirement. The equipment has also an automated temperature and salinity control and adjustment.

A Study of the Pelagic Larval Duration of Acropora humilis, Coral Recruitment and Connectivity in the Saudi Arabian Red Sea

KAUST Repository

Khalil, Maha

2011-01-01

Combined knowledge of the pelagic larval duration of coral species and coral recruitment patterns can provide evidence of inter-reef connectivity and indicate a reef’s ability to recover. We attempted to determine the maximum pelagic larval duration

Examining the eastern Amazon Basin breeze circulations, channeling and boundary layer properties using altitude controlled meteorological balloons

Science.gov (United States)

Fitzjarrald, D. R.; Voss, P. B.; Silva, R. D.; Callahan, S.; Dewald, A.; do Vale, R. S.

2017-12-01

During the period August 24-28, 2016, in a delayed component the GO-Amazon Project, we launched nine altitude-controlled free balloons (CMET). Smaller than typical rawinsondes, CMET are equipped with altitude control, global communication via Iridium satellite, and aspirated sensors. The aims of our effort were to examine the interactions among convective boundary layer and dual river breeze circulations near the confluence of the Tapajos and Amazon Rivers in the eastern Basin. The week-long field campaign was timed to examine the reestablishment of the breeze circulations shortly after the passage of a strong instability line on August 22. Nine CMET were launched at the Curua-Una hydroelectric dam (2.8S; 54.3W), timed to encounter the Tapajos river breeze front by late afternoon. Soundings were made to establish the thickness of interface between the easterly trade and westerly Tapajos breeze circulation. Careful use of sounding strategies allowed these free balloons to track along the northerly channeled flow in the lowest 300 m above the River. Following the river encounter, balloons tracked to the west, sounding to describe the diurnal course of boundary layer in the forest west of the Tapajos River. The longest flight traveled more than 770 km over three days and twice rested overnight in the rain forest canopy. Ancillary data from surface climate and flux stations as well as the Santarem radiosonde, satellite images will be used to illustrate how the breeze circulations are seen near the surface and how they were disrupted by larger-scale events. Comparisons with HYSPLIT trajectories will illustrate how sensitive real trajectories are to the refraction that the encounter with the breeze effects.

Biogeography and environmental genomics of the Roseobacter-affiliated pelagic CHAB-I-5 lineage

DEFF Research Database (Denmark)

Billerbeck, Sara; Wemheuer, Bernd; Voget, Sonja

2016-01-01

The identification and functional characterization of microbial communities remains a prevailing topic in microbial oceanography as information on environmentally relevant pelagic prokaryotes is still limited. The Roseobacter group, an abundant lineage of marine Alphaproteobacteria, can constitute...... large proportions of the bacterioplankton. Roseobacters also occur associated with eukaryotic organisms and possess streamlined as well as larger genomes from 2.2 to >5 Mpb. Here, we show that one pelagic cluster of this group, CHAB-I-5, occurs globally from tropical to polar regions and accounts for up...

Pelagic behaviour of reservoir fishes: sinusoidal swimming and associated behaviour

OpenAIRE

JAROLÍM, Oldřich

2009-01-01

Annotation Long-term fixed-location hydroacoustic study with uplooking transducer was performed during 2005 in Římov reservoir, Czech Republic. It dealt mainly with fish behaviour in the open water of reservoir, especially with sinusoidal swimming behaviour. The dependence of pelagic fish behaviour on environmental conditions was also studied.

Sedimentary record of subsidence pulse at the Triassic/Jurassic boundary interval in the Slovenian Basin (eastern Southern Alps

Directory of Open Access Journals (Sweden)

Rožič Boštjan

2017-08-01

Full Text Available In the Alpine Realm the Early Jurassic is characterized by the disintegration and partial drowning of vast platform areas. In the eastern part of the Southern Alps (present-day NW Slovenia, the Julian Carbonate Platform and the adjacent, E-W extending Slovenian Basin underwent partial disintegration, drowning and deepening from the Pliensbachian on, whereas only nominal environmental changes developed on the large Dinaric (Friuli, Adriatic Carbonate Platform to the south (structurally part of the Dinarides. These events, however, were preceded by an earlier - and as yet undocumented extensional event - that took place near the Triassic/Jurassic boundary. This paper provides evidence of an accelerated subsidence from four selected areas within the Slovenian Basin, which show a trend of eastwardly-decreasing deformation. In the westernmost (Mrzli vrh section - the Upper Triassic platform-margin - massive dolomite is overlain by the earliest Jurassic toe-of-slope carbonate resediments and further, by basin-plain micritic limestone. Further east (Perbla and Liščak sections the Triassic-Jurassic transition interval is marked by an increase in resedimented carbonates. We relate this to the increasing inclination and segmentation of the slope and adjacent basin floor. The easternmost (Mt. Porezen area shows a rather monotonous, latest Triassic-Early Jurassic basinal sedimentation. However, changes in the thickness of the Hettangian-Pliensbachian Krikov Formation point to a tilting of tectonic blocks within the basin area. Lateral facies changes at the base of the formation indicate that the tilting occurred at and/or shortly after the Triassic/Jurassic boundary

Sedimentary record of subsidence pulse at the Triassic/Jurassic boundary interval in the Slovenian Basin (eastern Southern Alps)

Science.gov (United States)

Rožič, Boštjan; Jurkovšek, Tea Kolar; Rožič, Petra Žvab; Gale, Luka

2017-08-01

In the Alpine Realm the Early Jurassic is characterized by the disintegration and partial drowning of vast platform areas. In the eastern part of the Southern Alps (present-day NW Slovenia), the Julian Carbonate Platform and the adjacent, E-W extending Slovenian Basin underwent partial disintegration, drowning and deepening from the Pliensbachian on, whereas only nominal environmental changes developed on the large Dinaric (Friuli, Adriatic) Carbonate Platform to the south (structurally part of the Dinarides). These events, however, were preceded by an earlier - and as yet undocumented extensional event - that took place near the Triassic/Jurassic boundary. This paper provides evidence of an accelerated subsidence from four selected areas within the Slovenian Basin, which show a trend of eastwardly-decreasing deformation. In the westernmost (Mrzli vrh) section - the Upper Triassic platform-margin - massive dolomite is overlain by the earliest Jurassic toe-of-slope carbonate resediments and further, by basin-plain micritic limestone. Further east (Perbla and Liščak sections) the Triassic-Jurassic transition interval is marked by an increase in resedimented carbonates. We relate this to the increasing inclination and segmentation of the slope and adjacent basin floor. The easternmost (Mt. Porezen) area shows a rather monotonous, latest Triassic-Early Jurassic basinal sedimentation. However, changes in the thickness of the Hettangian-Pliensbachian Krikov Formation point to a tilting of tectonic blocks within the basin area. Lateral facies changes at the base of the formation indicate that the tilting occurred at and/or shortly after the Triassic/Jurassic boundary

Intercontinental and intracontinental biogeography of the eastern Asian - Eastern North American disjunct Panax (the ginseng genus, Araliaceae), emphasizing its diversification processes in eastern Asia.

Science.gov (United States)

Zuo, Yun-Juan; Wen, Jun; Zhou, Shi-Liang

2017-12-01

The intercontinental biogeography between eastern Asia and eastern North America has attracted much attention from evolutionary biologists. Further insights into understanding the evolution of the intercontinental disjunctions have been hampered by the lack of studies on the intracontinental biogeography in eastern Asia, a region with complex geology, geography, climates and habitats. Herein we studied the biogeographic history of the eastern Asian-eastern North American disjunct genus Panax with special emphasis on the investigation of its uneven diversification in Asia. This study reconstructs the diversification history of Panax and also emphasizes a large clade of Panax taxa, which has a wide distribution in eastern Asia, but was unresolved in previous studies. We examined the noncoding plastid DNA fragments of trnH-psbA, rps16, and psbM-trnD, the mitochondrial b/c intron of NAD1, and the nuclear ribosomal internal transcribed spacer (ITS) region of 356 samples from 47 populations. The results revealed the subtropical Northern Hemisphere origin (Asia or Asia and North America) of Panax in the Paleocene. Intercontinental disjunctions between eastern Asia and eastern North America formed twice in Panax, once estimated in early Eocene for the split of P. trifolius and another in mid-Miocene for the divergence of P. quinquefolius. Intercontinental diversifications in Panax showed temporal correlation with the increase of global temperature. The evolutionary radiation of the P. bipinnatifidus species complex occurred around the boundary of Oligocene and Miocene. Strong genetic structure among populations of the species complex was detected and the populations may be isolated by distance. The backbone network and the Bayesian clustering analysis revealed a major evolutionary radiation centered in the Hengduan Mountains of western China. Our results suggested that the evolutionary radiation of Panax was promoted by geographic barriers, including mountain ranges

Surface mixing and biological activity in the four Eastern Boundary Upwelling Systems

Directory of Open Access Journals (Sweden)

V. Rossi

2009-08-01

Full Text Available Eastern Boundary Upwelling Systems (EBUS are characterized by a high productivity of plankton associated with large commercial fisheries, thus playing key biological and socio-economical roles. Since they are populated by several physical oceanic structures such as filaments and eddies, which interact with the biological processes, it is a major challenge to study this sub- and mesoscale activity in connection with the chlorophyll distribution. The aim of this work is to make a comparative study of these four upwelling systems focussing on their surface stirring, using the Finite Size Lyapunov Exponents (FSLEs, and their biological activity, based on satellite data. First, the spatial distribution of horizontal mixing is analysed from time averages and from probability density functions of FSLEs, which allow us to divide each areas in two different subsystems. Then we studied the temporal variability of surface stirring focussing on the annual and seasonal cycle. We also proposed a ranking of the four EBUS based on the averaged mixing intensity. When investigating the links with chlorophyll concentration, the previous subsystems reveal distinct biological signatures. There is a global negative correlation between surface horizontal mixing and chlorophyll standing stocks over the four areas. To try to better understand this inverse relationship, we consider the vertical dimension by looking at the Ekman-transport and vertical velocities. We suggest the possibility of a changing response of the phytoplankton to sub/mesoscale turbulence, from a negative effect in the very productive coastal areas to a positive one in the open ocean. This study provides new insights for the understanding of the variable biological productivity in the ocean, which results from both dynamics of the marine ecosystem and of the 3-D turbulent medium.

Characterizing driver-response relationships in marine pelagic ecosystems for improved ocean management.

Science.gov (United States)

Hunsicker, Mary E; Kappel, Carrie V; Selkoe, Kimberly A; Halpern, Benjamin S; Scarborough, Courtney; Mease, Lindley; Amrhein, Alisan

2016-04-01

Scientists and resource managers often use methods and tools that assume ecosystem components respond linearly to environmental drivers and human stressors. However, a growing body of literature demonstrates that many relationships are-non-linear, where small changes in a driver prompt a disproportionately large ecological response. We aim to provide a comprehensive assessment of the relationships between drivers and ecosystem components to identify where and when non-linearities are likely to occur. We focused our analyses on one of the best-studied marine systems, pelagic ecosystems, which allowed us to apply robust statistical techniques on a large pool of previously published studies. In this synthesis, we (1) conduct a wide literature review on single driver-response relationships in pelagic systems, (2) use statistical models to identify the degree of non-linearity in these relationships, and (3) assess whether general patterns exist in the strengths and shapes of non-linear relationships across drivers. Overall we found that non-linearities are common in pelagic ecosystems, comprising at least 52% of all driver-response relation- ships. This is likely an underestimate, as papers with higher quality data and analytical approaches reported non-linear relationships at a higher frequency (on average 11% more). Consequently, in the absence of evidence for a linear relationship, it is safer to assume a relationship is non-linear. Strong non-linearities can lead to greater ecological and socioeconomic consequences if they are unknown (and/or unanticipated), but if known they may provide clear thresholds to inform management targets. In pelagic systems, strongly non-linear relationships are often driven by climate and trophodynamic variables but are also associated with local stressors, such as overfishing and pollution, that can be more easily controlled by managers. Even when marine resource managers cannot influence ecosystem change, they can use information

Ontogenetic body-mass scaling of nitrogen excretion relates to body surface area in diverse pelagic invertebrates

DEFF Research Database (Denmark)

Hirst, Andrew G.; Lilley, M.K.S.; Glazier, D.S.

2017-01-01

. Among diverse pelagic invertebrates that change shape during ontogeny, recent analysis has demonstrated a significant positive correlation between the body-mass allometry of respiration rates (measured as the ontogenetic body mass-scaling exponent bR) and the allometry of body surface area (b......A, as predicted from body-shape changes using a Euclidean model). As many pelagic invertebrates use a large portion of their external body surface for both resource uptake and waste excretion, we predicted that body-mass scaling exponents for rates of excretion of soluble N (bN) should also then relate...... to the degree of body-shape change during growth. We tested this hypothesis using literature data on bN for 39 species of pelagic invertebrates across five different phyla, and find strong support: bN is significantly positively correlated with predicted bA, whilst also co-varying with bR. Intraspecific...

Investigations on pelagic food webs in mountain lakes - aims and methods

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Jirí NEDOMA

1999-08-01

Full Text Available A methodical approach for the assessment of pelagic biomass and the main carbon fluxes in remote and hardly accessible mountain lakes was elaborated and tested. Number and biomass of bacteria (BAC, autotrophic picoplankton (APP, heterotrophic nanoflagellates (HNF, ciliates (CIL, phytoplankton (PHY, zooplankton smaller than 40 μm (ZOOS and zooplankton larger than 40 μm (ZOOL were investigated regularly during two ice-free periods in 13 European mountain lakes (1st level approach – fixed samples elaborated in specialized laboratories. Carbon fluxes measured in 9 lakes included: primary production, exudation by PHY and BAC uptake of exudates, BAC production, elimination of BAC. These processes were measured in the field by specialized teams (2nd level approach. The ranges of values found in mountain lakes were evaluated and possible methodical and interpretative errors discussed. BAC were a significant component of pelagic biomass. The intercomparison between different partners showed differences in bacterial counts lower than 10%, whereas the mean cell volumes measured fluctuated by more than 40%. APP was never found in a significant quantity, except in one lake. HNF and CIL, though regularly found, were usually scarce and only occasionally significant in terms of biomass. The main components of pelagic biomass were BAC, PHY and ZOOL+ZOOS, except for acidified lakes, where zooplankton was very low. In oligotrophic mountain lakes, the percentage of extracellular production in the total primary production was considerable. Bacterial abundance and production often reached values quite comparable with the situation found in lowland mesotrophic lakes during winter.

50 CFR 229.36 - Atlantic Pelagic Longline Take Reduction Plan (PLTRP).

Science.gov (United States)

2010-10-01

... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS AUTHORIZATION FOR COMMERCIAL FISHERIES UNDER THE MARINE MAMMAL PROTECTION ACT OF 1972 Take Reduction Plan Regulations and Emergency... the U.S. east coast, a component of the Atlantic Ocean, Caribbean, Gulf of Mexico large pelagics...

Reflexions on Frasnian and Famennian stage boundary decisions as a guide to future deliberations

Science.gov (United States)

Ziegler, W.; Sandberg, C.A.

1996-01-01

The pros and cons of the three conodont-based boundaries of the Frasnian and Famennian Stages and their corresponding GSSPs (Global Stratotype Section and Point) are evaluated in terms of current taxonomic, biostratigraphic, and sedimentologic knowledge. Two of these boundaries are based on easily identified pelagic species, which provide excellent bases for global correlation. The third, for the base of the Frasnian, is based on a neritic species, whose taxonomy has been heatedly debated. The GSSPs for these three levels are all located in the Montagne Noire of southern France, partly because of political motivation to balance GSSPs selected in other regions. All three GSSPs are at levels from which global correlations cannot be effectively accomplished without aid from other, more complete sections or without making correlations strictly on the basis of taxonomic concepts - i. e., the entry of the definitive conodont species. Future deliberating bodies may want to reconsider the species chosen to delimit the base of the Frasnian and to select better GSSPs for all three boundaries.

Pelagic communities of the South West Indian Ocean seamounts: R/V Dr Fridtjof Nansen Cruise 2009-410

Science.gov (United States)

Rogers, A. D.; Alvheim, O.; Bemanaja, E.; Benivary, D.; Boersch-Supan, P.; Bornman, T. G.; Cedras, R.; Du Plessis, N.; Gotheil, S.; Høines, A.; Kemp, K.; Kristiansen, J.; Letessier, T.; Mangar, V.; Mazungula, N.; Mørk, T.; Pinet, P.; Pollard, R.; Read, J.; Sonnekus, T.

2017-02-01

The seamounts of the southern Indian Ocean remain some of the most poorly studied globally and yet have been subject to deep-sea fishing for decades and may face new exploitation through mining of seabed massive sulphides in the future. As an attempt to redress the knowledge deficit on deep-sea benthic and pelagic communities associated mainly with the seamounts of the South West Indian Ridge two cruises were undertaken to explore the pelagic and benthic ecology in 2009 and 2011 respectively. In this volume are presented studies on pelagic ecosystems around six seamounts, five on the South West Indian Ridge, including Atlantis Bank, Sapmer Seamount, Middle of What Seamount, Melville Bank and Coral Seamount and one un-named seamount on the Madagascar Ridge. In this paper, existing knowledge on the seamounts of the southwestern Indian Ocean is presented to provide context for the studies presented in this volume. An account of the overall aims, approaches and methods used primarily on the 2009 cruise are presented including metadata associated with sampling and some of the limitations of the study. Sampling during this cruise included physical oceanographic measurements, multibeam bathymetry, biological acoustics, and net sampling of phytoplankton, macrozooplankton and micronekton/nekton. The studies that follow reveal new data on the physical oceanography of this dynamic region of the oceans, and the important influence of water masses on the pelagic ecology associated with the seamounts of the South West Indian Ridge. New information on the pelagic fauna of the region fills an important biogeographic gap for the mid- to high-latitudes of the oceans of the southern hemisphere.

The importance of Hindeodus parvus (Conodonta for the definition of the Permian-Triassic boundary and evaluation of the proposed sections for a global stratotype section and point (GSSP for the base of the Triassic

Directory of Open Access Journals (Sweden)

Yurij D. Zakharov

1995-12-01

Full Text Available The biostratigraphic Permian/Triassic (P/T boundary is defined by the first appearance of H. parvus. The first appearance of H. parvus within the dine H. latidentatus-H. parvus is a globally recognizable event in the conodont evolution.The first appearance of H. parvus is not facies related and can be observed both in ammonoid-free shallow-water deposits and in ammonoid-bearing pelagic deposits. H. parvus is a common, easily determinable species known so far from the entire Tethys, Japan, western North America, Boreal realm (Greenlandand the Tethyan margin of Gondwana. H. parvus is the first species withworld-wide distribution to appear after the absolute minimum in the faunal diversity indicated by the minimum in The Meishan section (South China contains a continuous, pelagic sedimentaryrecord across the P/T boundary without stratigraphie gaps. It is nearly unaltered thermally (CAI = 1-1.5. Its fossil content (ammonoids, conodonts, foraminifers,bivalves, brachiopods, sporomorphs etc. and event succession have been thoroughlystudied. Absolute age and magnetostratigraphy have also been subjected to intensive studies. The section is readily accessible and under protection of the government. This section is best suitable as a global stratotype section and point (GSSP for the base of the Triassic. No other section in the world is known tobe qualified for defining the P/T boundary in a GSSP. H. parvus made its earliest appearence in the middle part of Boundary Bed 2 (Bed 27 at Meishan. It evolved within Bed 27 from H. latidentatus within a phylomorphogenetic continuum in a continuous and monofacial stratum. The biostratigraphic P/T boundary lies very close to the event boundary (15 cm above the event boundary at the baseof Boundary Bed 1 = Bed 25, and a few centimetres above the minimum in Ô'13C in the lower Boundary Bed 2.

Hypoxia Impacts on Food Web Linkages in a Pelagic Ecosystem

Science.gov (United States)

Sato, M.; Horne, J. K.; Parker-Stetter, S. L.; Essington, T.; Keister, J. E.; Moriarty, P.; Li, L.

2016-02-01

Low dissolved oxygen (DO), or hypoxia, causes significant disturbances on aquatic organisms, but the consequences for key food web linkages is not well understood. Here, we tested how the intensity of low DO events governs the degree of spatial overlap between pelagic zooplanktivorous fish and their zooplankton prey, fish feeding rates, and community compositions of zooplankton. We hypothesized that the greater sensitivity of fish to DO compared to zooplankton would lead to diminished spatial overlap at moderate DO and reduced feeding rates of fish, while severe hypoxia would amplify spatial overlap by preventing zooplankton from using deep refuge habitats leading to increased fish feeding rates. We also hypothesized shifts in zooplankton community composition towards less energetically profitable taxa such as small copepods and gelatinous species. We used a combination of multifrequency acoustic and net sampling for detecting distributions and abundance of zooplankton and pelagic fish in Hood Canal, WA, a seasonally hypoxic fjord. We employed a sampling design which paired hypoxic regions of Hood Canal with normoxic regions sampled prior to, during, and after the onset of hypoxia in two years. Contrary to our hypotheses, we found that fish and zooplankton did not change their horizontal and vertical distributions during periods and in locations with low DO levels. Consequently, the vertical overlap between fish and zooplankton did not change with DO. Fish feeding rates and the dominant zooplankton prey did not change with hypoxia events. The apparent resilience of fish to low DO in our system may be explained by decreased metabolic oxygen demand due to cool temperatures, increased availability and accessibility to their prey in low DO waters, or potential increase in predation risk at shallower depth. This study highlights the importance of both temperature and DO, instead of hypoxia threshold alone, in evaluating the impacts of hypoxia on pelagic communities.

Incidental catches of pelagic megafauna by the EU pelagic fleet in the Mauritanian exclusive economic zone during the year 2001 : results extracted from the scientific observer program

NARCIS (Netherlands)

Hofstede, ter R.

2003-01-01

The joint project between the Netherlands Institute for Fisheries Research (RIVO) and the Mauritanian Institute for Oceanography and Fisheries Research (IMROP) has been initiated in 1998 in order to strengthen Mauritania’s capacity for research on stocks of small pelagic fish. Part of this project

Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

International Nuclear Information System (INIS)

Queimaliños, Claudia; Reissig, Mariana; Diéguez, María del Carmen; Arcagni, Marina; Ribeiro Guevara, Sergio; Campbell, Linda; Soto Cárdenas, Carolina; Rapacioli, Raúl

2012-01-01

We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton δ 13 C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low ( −1 ) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk δ 13 C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: ► Pelagic allochthonous indicators were detected in two

Role of pelagic crustaceans in the diet of the longnose lancetfish ...

African Journals Online (AJOL)

The dietary trends of lancetfish are consistent with opportunistic feeding on the most abundant prey. They exploit short food chains based on carnivorous crustaceans, and play an important role in the pelagic trophic functioning of the western Indian Ocean. Keywords: crustaceans, feeding habits, lancetfish, seasonality, ...

Genetic Diversity and Population Structure of the Pelagic Thresher Shark (Alopias pelagicus) in the Pacific Ocean: Evidence for Two Evolutionarily Significant Units

Science.gov (United States)

Cardeñosa, Diego; Hyde, John; Caballero, Susana

2014-01-01

There has been an increasing concern about shark overexploitation in the last decade, especially for open ocean shark species, where there is a paucity of data about their life histories and population dynamics. Little is known regarding the population structure of the pelagic thresher shark, Alopias pelagicus. Though an earlier study using mtDNA control region data, showed evidence for differences between eastern and western Pacific populations, the study was hampered by low sample size and sparse geographic coverage, particularly a lack of samples from the central Pacific. Here, we present the population structure of Alopias pelagicus analyzing 351 samples from six different locations across the Pacific Ocean. Using data from mitochondrial DNA COI sequences and seven microsatellite loci we found evidence of strong population differentiation between western and eastern Pacific populations and evidence for reciprocally monophyly for organelle haplotypes and significant divergence of allele frequencies at nuclear loci, suggesting the existence of two Evolutionarily Significant Units (ESU) in the Pacific Ocean. Interestingly, the population in Hawaii appears to be composed of both ESUs in what seems to be clear sympatry with reproductive isolation. These results may indicate the existence of a new cryptic species in the Pacific Ocean. The presence of these distinct ESUs highlights the need for revised management plans for this highly exploited shark throughout its range. PMID:25337814

Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes

Science.gov (United States)

Frias-Torres, Sarrah; Bostater, Charles R., Jr.

2011-11-01

Biogeographical analyses provide insights on how the Deepwater Horizon oil spill impacted large pelagic fishes. We georeferenced historical ichthyoplankton surveys and published literature to map the spawning and larval areas of bluefin tuna, swordfish, blue marlin and whale shark sightings in the Gulf of Mexico with daily satellite-derived images detecting surface oil. The oil spill covered critical areas used by large pelagic fishes. Surface oil was detected in 100% of the northernmost whale shark sightings, in 32.8 % of the bluefin tuna spawning area and 38 % of the blue marlin larval area. No surface oil was detected in the swordfish spawning and larval area. Our study likely underestimates the extend of the oil spill due to satellite sensors detecting only the upper euphotic zone and the use of dispersants altering crude oil density, but provides a previously unknown spatio-temporal analysis.

EPA Townetting CTD casts - Evaluating the ecological health of Puget Sound's pelagic foodweb

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — To evaluate effects of human influence on the health of Puget Sound's pelagic ecosystems, we propose a sampling program across multiple oceanographic basins...

Remotely sensed wind speed predicts soaring behaviour in a wide-ranging pelagic seabird.

Science.gov (United States)

Gibb, Rory; Shoji, Akiko; Fayet, Annette L; Perrins, Chris M; Guilford, Tim; Freeman, Robin

2017-07-01

Global wind patterns affect flight strategies in many birds, including pelagic seabirds, many of which use wind-powered soaring to reduce energy costs during at-sea foraging trips and migration. Such long-distance movement patterns are underpinned by local interactions between wind conditions and flight behaviour, but these fine-scale relationships are far less well understood. Here we show that remotely sensed ocean wind speed and direction are highly significant predictors of soaring behaviour in a migratory pelagic seabird, the Manx shearwater ( Puffinus puffinus ). We used high-frequency GPS tracking data (10 Hz) and statistical behaviour state classification to identify two energetic modes in at-sea flight, corresponding to flap-like and soar-like flight. We show that soaring is significantly more likely to occur in tailwinds and crosswinds above a wind speed threshold of around 8 m s -1 , suggesting that these conditions enable birds to reduce metabolic costs by preferentially soaring over flapping. Our results suggest a behavioural mechanism by which wind conditions may shape foraging and migration ecology in pelagic seabirds, and thus indicate that shifts in wind patterns driven by climate change could impact this and other species. They also emphasize the emerging potential of high-frequency GPS biologgers to provide detailed quantitative insights into fine-scale flight behaviour in free-living animals. © 2017 The Author(s).

Determination of monomethylmercury and dimethylmercury in the Arctic marine boundary layer.

Science.gov (United States)

Baya, Pascale A; Gosselin, Michel; Lehnherr, Igor; St Louis, Vincent L; Hintelmann, Holger

2015-01-06

Our understanding of the biogeochemical cycling of monomethylmercury (MMHg) in the Arctic is incomplete because atmospheric sources and sinks of MMHg are still unclear. We sampled air in the Canadian Arctic marine boundary layer to quantify, for the first time, atmospheric concentrations of methylated Hg species (both MMHg and dimethylmercury (DMHg)), and, estimate the importance of atmospheric deposition as a source of MMHg to Arctic land- and sea-scapes. Overall atmospheric MMHg and DMHg concentrations (mean ± SD) were 2.9 ± 3.6 and 3.8 ± 3.1 (n = 37) pg m(-3), respectively. Concentrations of methylated Hg species in the marine boundary layer varied significantly among our sites, with a predominance of MMHg over Hudson Bay (HB), and DMHg over Canadian Arctic Archipelago (CAA) waters. We concluded that DMHg is of marine origin and that primary production rate and sea-ice cover are major drivers of its concentration in the Canadian Arctic marine boundary layer. Summer wet deposition rates of atmospheric MMHg, likely to be the product of DMHg degradation in the atmosphere, were estimated at 188 ± 117.5 ng m(-2) and 37 ± 21.7 ng m(-2) for HB and CAA, respectively, sustaining MMHg concentrations available for biomagnification in the pelagic food web.

Elasmobranch bycatch in the Italian Adriatic pelagic trawl fishery

Science.gov (United States)

Fortuna, Caterina Maria; Moro, Fabrizio; Sala, Antonello

2018-01-01

Elasmobranchs are among the most threatened long-lived marine species worldwide, and incidental capture is a major source of mortality. The northern central Adriatic Sea, though one of the most overfished basins of the Mediterranean Sea, supports a very valuable marine biodiversity, including elasmobranchs. This study assesses the impact of the northern central Adriatic pelagic trawl fishery on common smooth-hound (Mustelus mustelus), spiny dogfish (Squalus acanthias), common eagle ray (Myliobatis aquila), and pelagic stingray (Pteroplatytrygon violacea) by examining incidental catches recorded between 2006 and 2015. The distribution of bycatch events was evaluated using geo-referenced data. Generalized Linear Models were computed to standardize the catch of the four species and to predict the relative abundance of bycatch events. Data analysis shows that most bycatch events involving all four species occurred in the northern Adriatic Sea. The models predicted significant, distinct temporal patterns of standardized catches in line with previous investigations. Water depth, season, and fishing region were the best predictors to explain bycatch events. The present data suggest that the northern Adriatic may be an important nursery area for several elasmobranchs. They also highlight the urgent need for a better understanding of the interactions between elasmobranchs and fisheries to develop and apply suitable, ad hoc management measures. PMID:29377920

Elasmobranch bycatch in the Italian Adriatic pelagic trawl fishery.

Directory of Open Access Journals (Sweden)

Sara Bonanomi

Full Text Available Elasmobranchs are among the most threatened long-lived marine species worldwide, and incidental capture is a major source of mortality. The northern central Adriatic Sea, though one of the most overfished basins of the Mediterranean Sea, supports a very valuable marine biodiversity, including elasmobranchs. This study assesses the impact of the northern central Adriatic pelagic trawl fishery on common smooth-hound (Mustelus mustelus, spiny dogfish (Squalus acanthias, common eagle ray (Myliobatis aquila, and pelagic stingray (Pteroplatytrygon violacea by examining incidental catches recorded between 2006 and 2015. The distribution of bycatch events was evaluated using geo-referenced data. Generalized Linear Models were computed to standardize the catch of the four species and to predict the relative abundance of bycatch events. Data analysis shows that most bycatch events involving all four species occurred in the northern Adriatic Sea. The models predicted significant, distinct temporal patterns of standardized catches in line with previous investigations. Water depth, season, and fishing region were the best predictors to explain bycatch events. The present data suggest that the northern Adriatic may be an important nursery area for several elasmobranchs. They also highlight the urgent need for a better understanding of the interactions between elasmobranchs and fisheries to develop and apply suitable, ad hoc management measures.

Warm Bias and Parameterization of Boundary Upwelling in Ocean Models

Energy Technology Data Exchange (ETDEWEB)

Cessi, Paola; Wolfe, Christopher

2012-11-06

It has been demonstrated that Eastern Boundary Currents (EBC) are a baroclinic intensification of the interior circulation of the ocean due to the emergence of mesoscale eddies in response to the sharp buoyancy gradients driven by the wind-stress and the thermal surface forcing. The eddies accomplish the heat and salt transport necessary to insure that the subsurface flow is adiabatic, compensating for the heat and salt transport effected by the mean currents. The EBC thus generated occurs on a cross-shore scale of order 20-100 km, and thus this scale needs to be resolved in climate models in order to capture the meridional transport by the EBC. Our result indicate that changes in the near shore currents on the oceanic eastern boundaries are linked not just to local forcing, such as coastal changes in the winds, but depend on the basin-wide circulation as well.

Trophodynamics and diet overlap of small pelagic fish species in the Bay of Biscay

KAUST Repository

Bachiller, E

2015-08-27

Small pelagic fish are the link between planktonic production and higher trophic levels. Competition for resources may play a role in the population dynamics of species, some of them probably standing out from the others due to greater feeding success. It is therefore important to understand the trophic niche of species overlapping both spatially and temporally. In this study, we have investigated the diet, prey preference, trophic niche breadth and diet overlap of the 8 major small pelagic species (anchovy, sardine, sprat, Atlantic and Mediterranean horse mackerel, bogue, Atlantic mackerel and Atlantic chub mackerel) inhabiting the Bay of Biscay. Results indicate that all fish feed mainly on calanoid copepods, incorporating larger prey like euphausiids and decapods to complete their diet. Differences in ingested prey diversity seem to be more limited by the available zooplankton at sea than by a specific diet preference by fish species, resulting in an overall high diet overlap, especially within clupeids but also between clupeids and other (larger) predator species. Consumption estimations for different prey groups could therefore determine whether such a large diet overlap between small pelagic fish, together with spatial co-occurrence, results in competition or enhances the effects of intraguild predation, which is important in terms of an ecosystem approach to fisheries management.

Trophodynamics and diet overlap of small pelagic fish species in the Bay of Biscay

KAUST Repository

Bachiller, E; Irigoien, Xabier

2015-01-01

Small pelagic fish are the link between planktonic production and higher trophic levels. Competition for resources may play a role in the population dynamics of species, some of them probably standing out from the others due to greater feeding success. It is therefore important to understand the trophic niche of species overlapping both spatially and temporally. In this study, we have investigated the diet, prey preference, trophic niche breadth and diet overlap of the 8 major small pelagic species (anchovy, sardine, sprat, Atlantic and Mediterranean horse mackerel, bogue, Atlantic mackerel and Atlantic chub mackerel) inhabiting the Bay of Biscay. Results indicate that all fish feed mainly on calanoid copepods, incorporating larger prey like euphausiids and decapods to complete their diet. Differences in ingested prey diversity seem to be more limited by the available zooplankton at sea than by a specific diet preference by fish species, resulting in an overall high diet overlap, especially within clupeids but also between clupeids and other (larger) predator species. Consumption estimations for different prey groups could therefore determine whether such a large diet overlap between small pelagic fish, together with spatial co-occurrence, results in competition or enhances the effects of intraguild predation, which is important in terms of an ecosystem approach to fisheries management.

Paleoenvironmental changes across the Cretaceous/Tertiary boundary in the northern Clarence valley, southeastern Marlborough, New Zealand

International Nuclear Information System (INIS)

Hollis, C.J.; Rodgers, K.A.; Strong, C.P.; Field, B.D.; Rogers, K.M.

2003-01-01

Strata outcropping in Mead and Branch Streams, northern Clarence valley, provide important records of pelagic-hemipelagic sedimentation through the Cretaceous-Paleocene transition in a southern high-latitude, upwelling system flanking a carbonate platform. The two stream sections, 13 C) indicate that high biological productivity continued across the K/T boundary and through the biosiliceous episode. Siliceous plankton thrived in the Marlborough upwelling zone during the Early Paleocene. Fluctuations in abundance and lithofacies can be related to significant changes in sea level, which may be the result of local tectonic or global climate changes. The delayed recovery of calcareous plankton after mass extinction at the K/T boundary, in both outer neritic and bathyal settings, indicates a relatively cool oceanic regime for the first 1.5 m.y. of the Paleocene. (author). 68 refs., 11 figs., 6 tabs

Effects of changing nutrient inputs on the ratio of small pelagic fish stock and phytoplankton biomass in the Black Sea

Science.gov (United States)

Yunev, Oleg A.; Velikova, Violeta; Carstensen, Jacob

2017-10-01

Significant increases in nitrogen and phosphorus inputs to the Black Sea in the second half of the 20th century caused eutrophication and drastically decreasing Si:N and Si:P ratios. Combined with climate change, overfishing of top predators and a huge outbreak of the non-indigenous ctenophore Mnemiopsis, the pelagic food web was strongly modified and its efficiency for channeling primary production to higher trophic levels substantially reduced. We used the ratio between small pelagic fish stock and phytoplankton biomass on the Danube shelf and in the open Black Sea to investigate long-term changes in food web functioning. The ratio had 1) highest values for the pre-eutrophication period when diatoms and copepods dominated the pelagic food web ('muscle food chain'), 2) decreased during the eutrophication period with stronger prevalence of autotrophic pico- and nanophytoplankton, bacteria, heterotrophic nanoflagellates, microzooplankton, Noctiluca and jellyfish ('jelly food chain' with increased importance of the microbial loop), 3) lowest values during the ecological crisis (1989-1992), when small pelagic fish stocks collapsed, and 4) increased after 1993, indicating that the ecosystem went out of the crisis and exhibited a trend of recovery. However, in the last period (1993-2008) the ratio remained close to values observed in the middle eutrophication phase, suggesting that the ecosystem was far from fully recovered. Since early 2000s, fluctuating pelagic fish stocks, with a tendency to decreasing fish landing again, have been observed in the Black Sea. Additionally, the quality of food for the small pelagic fish has deteriorated due to warming trends and the legacy of eutrophication, giving support for the 'jelly food chain', exhibiting low energy transfer and prevalence of organisms with high respiration rate and low nutritional value.

Deep pelagic food web structure as revealed by in situ feeding observations.

Science.gov (United States)

Choy, C Anela; Haddock, Steven H D; Robison, Bruce H

2017-12-06

Food web linkages, or the feeding relationships between species inhabiting a shared ecosystem, are an ecological lens through which ecosystem structure and function can be assessed, and thus are fundamental to informing sustainable resource management. Empirical feeding datasets have traditionally been painstakingly generated from stomach content analysis, direct observations and from biochemical trophic markers (stable isotopes, fatty acids, molecular tools). Each approach carries inherent biases and limitations, as well as advantages. Here, using 27 years (1991-2016) of in situ feeding observations collected by remotely operated vehicles (ROVs), we quantitatively characterize the deep pelagic food web of central California within the California Current, complementing existing studies of diet and trophic interactions with a unique perspective. Seven hundred and forty-three independent feeding events were observed with ROVs from near-surface waters down to depths approaching 4000 m, involving an assemblage of 84 different predators and 82 different prey types, for a total of 242 unique feeding relationships. The greatest diversity of prey was consumed by narcomedusae, followed by physonect siphonophores, ctenophores and cephalopods. We highlight key interactions within the poorly understood 'jelly web', showing the importance of medusae, ctenophores and siphonophores as key predators, whose ecological significance is comparable to large fish and squid species within the central California deep pelagic food web. Gelatinous predators are often thought to comprise relatively inefficient trophic pathways within marine communities, but we build upon previous findings to document their substantial and integral roles in deep pelagic food webs. © 2017 The Authors.

Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

Energy Technology Data Exchange (ETDEWEB)

Queimalinos, Claudia, E-mail: queimalinosc@comahue-conicet.gob.ar [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Reissig, Mariana; Dieguez, Maria del Carmen [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Arcagni, Marina; Ribeiro Guevara, Sergio [Laboratorio de Analisis por Activacion Neutronica (LAAN), Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Av. Bustillo 9500, R8402AGP Bariloche, Rio Negro (Argentina); Campbell, Linda [School of Environmental Studies, Saint Mary' s University, 923 Robie Street, Halifax, Nova Scotia, Canada B3H-3C3 (Canada); Soto Cardenas, Carolina [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Rapacioli, Raul [Facultad de Ingenieria, Universidad Nacional del Comahue, Buenos Aires1400, Q8300IBX Neuquen (Argentina); and others

2012-06-15

We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton {delta}{sup 13}C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low (< 0.28 m{sup -1}) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk {delta}{sup 13}C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: Black-Right-Pointing-Pointer Pelagic

Bacteria and pelagic food webs in Pristine alpine lakes (Retezat Mountains, Romania)

Czech Academy of Sciences Publication Activity Database

Straškrábová, Viera; Cogalniceanu, D.; Nedoma, Jiří; Parpala, L.; Postolache, C.; Tudorancea, C.; Vadineanu, A.; Valcu, C. M.; Zinevici, V.

2006-01-01

Roč. 3, - (2006), s. 1-10 ISSN 1841-7051 Grant - others:EC(XE) EVK1-CT-1999-00032; EC(XE) GOCE-CT-2003-505298 Institutional research plan: CEZ:AV0Z60170517 Keywords : alpine lakes * pelagic bacteria * chlorophyll * zooplankton Subject RIV: EH - Ecology, Behaviour

Energy density of marine pelagic fish eggs

DEFF Research Database (Denmark)

Riis-Vestergaard, J.

2002-01-01

Analysis of the literature on pelagic fish eggs enabled generalizations to be made of their energy densities, because the property of being buoyant in sea water appears to constrain the proximate composition of the eggs and thus to minimize interspecific variation. An energy density of 1.34 J mul......(-1) of total egg volume is derived for most species spawning eggs without visible oil globules. The energy density of eggs with oil globules is predicted by (σ) over cap = 1.34 + 40.61 x (J mul(-1)) where x is the fractional volume of the oil globule. (C) 2002 The Fisheries Society of the British...

Investigation of the atmospheric boundary layer dynamics during the ESCOMPTE campaign

OpenAIRE

F. Saïd; A. Brut; B. Campistron; F. Cousin

2007-01-01

International audience; This paper presents some results about the behavior of the atmospheric boundary layer observed during the ESCOMPTE experiment. This campaign, which took place in south-eastern France during summer 2001, was aimed at improving our understanding of pollution episodes in relation to the dynamics of the lower troposphere. Using a large data set, as well as a simulation from the mesoscale non-hydrostatic model Meso-NH, we describe and analyze the atmospheric boundary layer ...

Swarming of pelagic tunicates associated with phytoplankton bloom in the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Madhupratap, M.; Devassy, V.P.; Nair, S.R.S.; Rao, T.S.S.

During the 40th cruise of R V Gaveshani, a large swarm pelagic tunicates associated with a bloom of diatoms and blue green algae was observed off Nagapattinam. The doliolid Dolioletta gegenbauri, Uljanin, the salp Thalia democratica Forskal...

75 FR 1023 - International Fisheries Regulations; Fisheries in the Western Pacific; Pelagic Fisheries; Hawaii...

Science.gov (United States)

2010-01-08

...; Pelagic Fisheries; Hawaii-based Shallow-set Longline Fishery; Correction AGENCY: National Marine Fisheries... process is preserved for closing the Hawaii-based shallow-set longline fishery as a result of the fishery...

Pelagic tar and plastic in the Gulf of Alaska and Bering Sea: 1975

Energy Technology Data Exchange (ETDEWEB)

Shaw, D G

1977-07-01

Seventy-one tows of 740 m/sup 2/ each were made in search of pelagic tar and plastics in the Gulf of Alaska and Bering Sea during the period October 1974 to October 1975. Tar was observed on nine occasions while plastics were found six times. The arithmetic mean value of tar abundance, 3.3 x 10/sup -3/ mg/m/sup 2/, is considerably lower than most other oceanic areas for which values have been reported. Gas chromatographic analysis of this tar indicates that it is more extensively weathered than tar from the north Atlantic. An estimate of the abundance of tar lumps too small to be sampled by net tows is made based on the assumption that there are equal weights of particles in logarithmetically equal size intervals. The abundance of pelagic plastics is also low.

Reconstructing source-sink dynamics in a population with a pelagic dispersal phase.

Directory of Open Access Journals (Sweden)

Kun Chen

Full Text Available For many organisms, the reconstruction of source-sink dynamics is hampered by limited knowledge of the spatial assemblage of either the source or sink components or lack of information on the strength of the linkage for any source-sink pair. In the case of marine species with a pelagic dispersal phase, these problems may be mitigated through the use of particle drift simulations based on an ocean circulation model. However, when simulated particle trajectories do not intersect sampling sites, the corroboration of model drift simulations with field data is hampered. Here, we apply a new statistical approach for reconstructing source-sink dynamics that overcomes the aforementioned problems. Our research is motivated by the need for understanding observed changes in jellyfish distributions in the eastern Bering Sea since 1990. By contrasting the source-sink dynamics reconstructed with data from the pre-1990 period with that from the post-1990 period, it appears that changes in jellyfish distribution resulted from the combined effects of higher jellyfish productivity and longer dispersal of jellyfish resulting from a shift in the ocean circulation starting in 1991. A sensitivity analysis suggests that the source-sink reconstruction is robust to typical systematic and random errors in the ocean circulation model driving the particle drift simulations. The jellyfish analysis illustrates that new insights can be gained by studying structural changes in source-sink dynamics. The proposed approach is applicable for the spatial source-sink reconstruction of other species and even abiotic processes, such as sediment transport.

EPA2011 Microbial & nutrient database - Evaluating the ecological health of Puget Sound's pelagic foodweb

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — To evaluate effects of human influence on the health of Puget Sound's pelagic ecosystems, we propose a sampling program across multiple oceanographic basins...

Ozone and carbon monoxide budgets over the Eastern Mediterranean.

Science.gov (United States)

Myriokefalitakis, S; Daskalakis, N; Fanourgakis, G S; Voulgarakis, A; Krol, M C; Aan de Brugh, J M J; Kanakidou, M

2016-09-01

The importance of the long-range transport (LRT) on O3 and CO budgets over the Eastern Mediterranean has been investigated using the state-of-the-art 3-dimensional global chemistry-transport model TM4-ECPL. A 3-D budget analysis has been performed separating the Eastern from the Western basins and the boundary layer (BL) from the free troposphere (FT). The FT of the Eastern Mediterranean is shown to be a strong receptor of polluted air masses from the Western Mediterranean, and the most important source of polluted air masses for the Eastern Mediterranean BL, with about 40% of O3 and of CO in the BL to be transported from the FT aloft. Regional anthropogenic sources are found to have relatively small impact on regional air quality in the area, contributing by about 8% and 18% to surface levels of O3 and CO, respectively. Projections using anthropogenic emissions for the year 2050 but neglecting climate change calculate a surface O3 decrease of about 11% together with a surface CO increase of roughly 10% in the Eastern Mediterranean. Copyright © 2016 Elsevier B.V. All rights reserved.

Stable Isotope Food Web Analysis of a Large Subtropical Lake: Alternative Explanations for 15N Enrichment of Pelagic vs. Littoral Fisheries

Directory of Open Access Journals (Sweden)

Karl E. Havens

2003-01-01

Full Text Available The food webs of littoral, pelagic, and littoral-pelagic ecotone (interface regions of a large subtropical lake were investigated using stable isotope ratio methods, expanding the focus of a previous fish-only study to include other food web components such as primary producers and invertebrates. In these food webs, δ13C increased ~4o/oo and δ15N increased ~10o/oo from primary producers to fish. The δ15N of fish was ~9o/oo in the littoral zone, ~10 o/oo in the ecotone, and ~12o/oo in the pelagic zone. The cross-habitat enrichment in fish 15N corresponded with both an increase in the size of fish and an increase in the δ15N of primary consumers (mollusks. Despite larger body size in the pelagic zone, fish in all three habitats appear to occur at the same average trophic level (TL = 4, assuming an enrichment factor of 3.4o/oo per trophic level, and normalizing to the δ15N of primary consumers.

Microbiological assessment along the fish production chain of the Norwegian pelagic fisheries sector--Results from a spot sampling programme.

Science.gov (United States)

Svanevik, Cecilie Smith; Roiha, Irja Sunde; Levsen, Arne; Lunestad, Bjørn Tore

2015-10-01

Microbes play an important role in the degradation of fish products, thus better knowledge of the microbiological conditions throughout the fish production chain may help to optimise product quality and resource utilisation. This paper presents the results of a ten-year spot sampling programme (2005-2014) of the commercially most important pelagic fish species harvested in Norway. Fish-, surface-, and storage water samples were collected from fishing vessels and processing factories. Totally 1,181 samples were assessed with respect to microbiological quality, hygiene and food safety. We introduce a quality and safety assessment scheme for fresh pelagic fish recommending limits for heterotrophic plate counts (HPC), thermos tolerant coliforms, enterococci and Listeria monocytogenes. According to the scheme, in 25 of 41 samplings, sub-optimal conditions were found with respect to quality, whereas in 21 and 9 samplings, samples were not in compliance concerning hygiene and food safety, respectively. The present study has revealed that the quality of pelagic fish can be optimised by improving the hygiene conditions at some critical points at an early phase of the production chain. Thus, the proposed assessment scheme may provide a useful tool for the industry to optimise quality and maintain consumer safety of pelagic fishery products. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Trophodynamics of Organic Pollutants in Pelagic and Benthic Food Webs of Lake Dianchi: Importance of Ingested Sediment As Uptake Route.

Science.gov (United States)

Fan, Senrong; Wang, Beili; Liu, Hang; Gao, Shixiong; Li, Tong; Wang, Shuran; Liu, Yong; Liu, Xueqin; Wan, Yi

2017-12-19

Habitat is of great importance in determining the trophic transfer of pollutants in freshwater ecosystems; however, the major factors influencing chemical trophodynamics in pelagic and benthic food webs remain unclear. This study investigated the levels of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), polycyclic aromatic hydrocarbons (PAHs), and substituted PAHs (s-PAHs) in 2 plankton species, 6 invertebrate species, and 10 fish species collected from Lake Dianchi in southern China. Relatively high concentrations of PAHs and s-PAHs were detected with total concentrations of 11.4-1400 ng/g wet weight (ww) and 5.3-115 ng/g ww, respectively. Stable isotope analysis and stomach content analysis were applied to quantitatively determine the trophic level of individual organisms and discriminate between pelagic and benthic pathways, and the trophodynamics of the detected compounds in the two food webs were assessed. P,p'-DDE was found to exhibit relatively higher trophic magnification rate in the pelagic food web than in the benthic food web. In contrast, PAHs and s-PAHs exhibited greater dilution rates along the trophic levels in the pelagic food web. The lower species differences of pollutants accumulated in benthic organisms compared to pelagic organisms is attributable to extra uptake via ingested sediment in benthos. The average uptake proportions of PAHs and s-PAHs via ingested sediment in benthic biotas were estimated to be 31-77%, and that of p,p'-DDE was 46%. The uptake routes are of importance for assessing the trophic magnification potentials of organic pollutants, especially in eutrophic freshwater ecosystems.

Long-Term Monitoring of Dolphin Biosonar Activity in Deep Pelagic Waters of the Mediterranean Sea.

Science.gov (United States)

Caruso, Francesco; Alonge, Giuseppe; Bellia, Giorgio; De Domenico, Emilio; Grammauta, Rosario; Larosa, Giuseppina; Mazzola, Salvatore; Riccobene, Giorgio; Pavan, Gianni; Papale, Elena; Pellegrino, Carmelo; Pulvirenti, Sara; Sciacca, Virginia; Simeone, Francesco; Speziale, Fabrizio; Viola, Salvatore; Buscaino, Giuseppa

2017-06-28

Dolphins emit short ultrasonic pulses (clicks) to acquire information about the surrounding environment, prey and habitat features. We investigated Delphinidae activity over multiple temporal scales through the detection of their echolocation clicks, using long-term Passive Acoustic Monitoring (PAM). The Istituto Nazionale di Fisica Nucleare operates multidisciplinary seafloor observatories in a deep area of the Central Mediterranean Sea. The Ocean noise Detection Experiment collected data offshore the Gulf of Catania from January 2005 to November 2006, allowing the study of temporal patterns of dolphin activity in this deep pelagic zone for the first time. Nearly 5,500 five-minute recordings acquired over two years were examined using spectrogram analysis and through development and testing of an automatic detection algorithm. Echolocation activity of dolphins was mostly confined to nighttime and crepuscular hours, in contrast with communicative signals (whistles). Seasonal variation, with a peak number of clicks in August, was also evident, but no effect of lunar cycle was observed. Temporal trends in echolocation corresponded to environmental and trophic variability known in the deep pelagic waters of the Ionian Sea. Long-term PAM and the continued development of automatic analysis techniques are essential to advancing the study of pelagic marine mammal distribution and behaviour patterns.

Pelagic Iron Recycling in the Southern Ocean: Exploring the Contribution of Marine Animals

Directory of Open Access Journals (Sweden)

Lavenia Ratnarajah

2018-03-01

Full Text Available The availability of iron controls primary productivity in large areas of the Southern Ocean. Iron is largely supplied via atmospheric dust deposition, melting ice, the weathering of shelf sediments, upwelling, sediment resuspension, mixing (deep water, biogenic, and vertical mixing and hydrothermal vents with varying degrees of temporal and spatial importance. However, large areas of the Southern Ocean are remote from these sources, leading to regions of low primary productivity. Recent studies suggest that recycling of iron by animals in the surface layer could enhance primary productivity in the Southern Ocean. The aim of this review is to provide a quantitative and qualitative assessment of the current literature on pelagic iron recycling by marine animals in the Southern Ocean and highlight the next steps forward in quantifying the retention and recycling of iron by higher trophic levels in the Southern Ocean. Phytoplankton utilize the iron in seawater to meet their metabolic demand. Through grazing, pelagic herbivores transfer the iron in phytoplankton cells into their body tissues and organs. Herbivores can recycle iron through inefficient feeding behavior that release iron into the water before ingestion, and through the release of fecal pellets. The iron stored within herbivores is transferred to higher trophic levels when they are consumed. When predators consume iron beyond their metabolic demand it is either excreted or defecated. Waste products from pelagic vertebrates can thus contain high concentrations of iron which may be in a form that is available to phytoplankton. Bioavailability of fecal iron for phytoplankton growth is influenced by a combination of the size of the fecal particle, presence of organic ligands, the oxidation state of the iron, as well as biological (e.g., remineralization, coprochaly, coprorhexy, and coprophagy and physical (e.g., dissolution, fragmentation processes that lead to the degradation and release of

A Qualitative and Quantitative Study of the Distribution of Pelagic Sediment in the Atlantic Basin

National Research Council Canada - National Science Library

Webb, Helen

1997-01-01

By numerically modeling pelagic sedimentation as a diffusive process, we study sedimentation effects in terms of stochastic parameters including seafloor RMS height, abyssal hill spacing, and slope distribution...

Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment

NARCIS (Netherlands)

Spilling, K.; Schulz, K.G.; Paul, A.J.; Boxhammer, T.; Achterberg, E.P.; Hornick, T.; Lischka, S.; Stuhr, A.; Bermúdez, R.; Czerny, J.; Crawfurd, K.; Brussaard, C.P.D.; Grossart, H.-P.; Riebesell, U.

2016-01-01

About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging

Recreational fishery catch and effort estimates for large pelagic species from Maine through Virginia from 2002-06-01 to 2014-10-31 (NCEI Accession 0137959)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — On the Atlantic Coast from Maine to Virginia, NOAA Fisheries uses the Large Pelagics Survey (LPS) to measure the total recreational catch of large pelagics fish...

Sediments and fossiliferous rocks from the eastern side of the Tongue of the Ocean, Bahamas

Science.gov (United States)

Gibson, T.G.; Schlee, J.

1967-01-01

In August 1966, two dives were made with the deep-diving submersible Alvin along the eastern side of the Tongue of the Ocean to sample the rock and sediment. Physiographically, the area is marked by steep slopes of silty carbonate sediment and precipitous rock cliffs dusted by carbonate debris. Three rocks, obtained from the lower and middle side of the canyon (914-1676 m depth), are late Miocene-early Pliocene to late Pleistocene-Recent in age; all are deep-water pelagic limestones. They show (i) that the Tongue of the Ocean has been a deep-water area at least back into the Miocene, and (ii) that much shallow-water detritus has been swept off neighbouring banks to be incorporated with the deep-water fauna in the sediment. ?? 1967 Pergamon Press Ltd.

Late Ordovician brachiopods from eastern North Greenland

DEFF Research Database (Denmark)

Mac Ørum Rasmussen, Christian

2013-01-01

Late Ordovician rhynchonelliformean brachiopods, typical of the North American Red River fauna, are found sporadically in the BOrglum River Formation of the Centrum SO area, Kronprins Christian Land, eastern North Greenland. The geographical distribution of this characteristic brachiopod fauna......) to younger strata exclusively yielding specimens of H.gigas. As H.gigas occurs in the upper part of the Cape Calhoun Formation in Washington Land, it indicates that the upper boundary of the Cape Calhoun Formation is considerably younger than previous estimates, reaching into the uppermost Katian (middle...... (Richmondian), it possesses a strong provincial signal during the later Ordovician. The new occurrences indicate that this fauna extended to the north-eastern margin of the Laurentian Craton. It lived in close association with cosmopolitan faunal elements that may have been the earliest sign of the succeeding...

Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin

DEFF Research Database (Denmark)

Clemmensen, Anne; Thomsen, Erik

2005-01-01

cores from Storebælt in the eastern part of the North Sea Basin, we have reconstructed the palaeoenvironmental changes across the boundary. The benthic foraminiferal faunas belong to the “Midway-type fauna”. They are extremely rich and more than 260 taxa have been recognized. Q-mode cluster analysis......, the sea bottom conditions became colder and more acidic. This resulted in partial dissolution of the carbonates and the deposition shifted from marl to clay. Comparison with records from the Western Pyrenees, the Nile Basin and the eastern North America suggests that sea-level changes across the Danian......The Danian–Selandian boundary (not, vert, similar60 Ma) marks the cessation of 40 million years of carbonate deposition in the North Sea Basin and a shift to siliciclastic deposition. On the basis of variations in lithology, benthic and planktonic foraminifera and calcareous nannofossils in three...

Diet composition and food habits of demersal and pelagic marine fishes from Terengganu waters, east coast of Peninsular Malaysia

OpenAIRE

Bachok, Z.; Mansor, M.I.; Noordin, R.M.

2004-01-01

Fish stomachs from 18 demersal and pelagic fishes from the coast of Terengganu in Malaysia were examined. The components of the fishesÆ diets varied in number, weight, and their frequency of occurrence. The major food items in the stomachs of each species were determined using an Index of Relative Importance. A "conceptualö food web structure indicates that fish species in the study area can be classified into three predatory groups: (1) predators on largely planktivorous or pelagic species; ...

Multi-scale model analysis of boundary layer ozone over East Asia

Directory of Open Access Journals (Sweden)

M. Lin

2009-05-01

Full Text Available This study employs the regional Community Multiscale Air Quality (CMAQ model to examine seasonal and diurnal variations of boundary layer ozone (O₃ over East Asia. We evaluate the response of model simulations of boundary layer O₃ to the choice of chemical mechanisms, meteorological fields, boundary conditions, and model resolutions. Data obtained from surface stations, aircraft measurements, and satellites are used to advance understanding of O₃ chemistry and mechanisms over East Asia and evaluate how well the model represents the observed features. Satellite measurements and model simulations of summertime rainfall are used to assess the impact of the Asian monsoon on O₃ production. Our results suggest that summertime O₃ over Central Eastern China is highly sensitive to cloud cover and monsoonal rainfall over this region. Thus, accurate simulation of the East Asia summer monsoon is critical to model analysis of atmospheric chemistry over China. Examination of hourly summertime O₃ mixing ratios from sites in Japan confirms the important role of diurnal boundary layer fluctuations in controlling ground-level O₃. By comparing five different model configurations with observations at six sites, the specific mechanisms responsible for model behavior are identified and discussed. In particular, vertical mixing, urban chemistry, and dry deposition depending on boundary layer height strongly affect model ability to capture observed behavior. Central Eastern China appears to be the most sensitive region in our study to the choice of chemical mechanisms. Evaluation with TRACE-P aircraft measurements reveals that neither the CB4 nor the SAPRC99 mechanisms consistently capture observed behavior of key photochemical oxidants in springtime. However, our analysis finds that SAPRC99 performs somewhat better in simulating mixing ratios of H₂O₂ (hydrogen peroxide

Diagenesis of lower Cretaceous pelagic carbonates, North Atlantic: Paleoceanographic signals obscured

Science.gov (United States)

Frank, T.D.; Arthur, M.A.; Dean, W.E.

1999-01-01

The stable isotope and minor element geochemistry of Neocomian (Lower Cretaceous) pelagic carbonates of the North Atlantic Basin (Deep Sea Drilling Project Sites 105, 367, 387, 391, and 603) was examined to develop a diagenetic model for pelagic limestones. In particular, we hoped to test the fidelity of whole-rock geochemical records as paleoceanographic indicators for pelagic deposits of pre-Aptian age, in which individual microfossils are not available for analysis. Data indicate that in addition to depth of burial, rhythmic variations in primary carbonate content have strongly controlled diagenetic patterns and associated geochemical signatures in these Neocomian sequences. Samples become increasingly depleted in Sr and 18O with increasing CaCO3 content. Within individual sedimentary sections, substantial decreases in Sr/Ca ratios and ??18O values are evident over a range of 4 to 98% CaCO3. However, even over a relatively narrow range of 50 to 98% CaCO3 a 2.5%c variation in ??18O values and a change of a factor of 1.7 in Sr/Ca ratios are observed. Carbon isotope compositions do not vary as extensively with CaCO3 content, but carbonate-rich intervals tend to be relatively depleted in 13C. Petrographic analysis reveals that these geochemical patterns are related to the transfer of CaCO3 from carbonate-poor intervals (calcareous shales and marlstones) to adjacent carbonate-rich intervals (limestones) during burial compaction and pressure solution. This process results in the addition of diagenetic cement to carbonate-rich intervals to produce a bulk composition that is relatively depleted in Sr and 18O and, at the same time, enables the retention of more-or-less primary carbonate that is relatively enriched in Sr and 18O in adjacent carbonate-poor intervals. Thus, although cyclic variations in CaCO3 content are primary in the Neocomian sequences examined, measured variations in Sr/Ca ratios and ??18O values are not and, as such, do not provide reliable proxies for

Palynology of uppermost Jurassic and lowermost Cretaceous strata in the Eastern Netherlands

NARCIS (Netherlands)

Burger, D.

1965-01-01

The present investigation is a systematical treatment of the sporomorphs from strata at the Jurassic-Cretaceous boundary in the eastern Netherlands Twente area, and an attempt to apply palynology to detailed stratigraphical study, by making use of quantitative pollen analyses. The rock samples used

High diversity, low disparity and small body size in plesiosaurs (Reptilia, Sauropterygia from the Triassic-Jurassic boundary.

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Roger B J Benson

Full Text Available Invasion of the open ocean by tetrapods represents a major evolutionary transition that occurred independently in cetaceans, mosasauroids, chelonioids (sea turtles, ichthyosaurs and plesiosaurs. Plesiosaurian reptiles invaded pelagic ocean environments immediately following the Late Triassic extinctions. This diversification is recorded by three intensively-sampled European fossil faunas, spanning 20 million years (Ma. These provide an unparalleled opportunity to document changes in key macroevolutionary parameters associated with secondary adaptation to pelagic life in tetrapods. A comprehensive assessment focuses on the oldest fauna, from the Blue Lias Formation of Street, and nearby localities, in Somerset, UK (Earliest Jurassic: 200 Ma, identifying three new species representing two small-bodied rhomaleosaurids (Stratesaurus taylori gen et sp. nov.; Avalonnectes arturi gen. et sp. nov and the most basal plesiosauroid, Eoplesiosaurus antiquior gen. et sp. nov. The initial radiation of plesiosaurs was characterised by high, but short-lived, diversity of an archaic clade, Rhomaleosauridae. Representatives of this initial radiation were replaced by derived, neoplesiosaurian plesiosaurs at small-medium body sizes during a more gradual accumulation of morphological disparity. This gradualistic modality suggests that adaptive radiations within tetrapod subclades are not always characterised by the initially high levels of disparity observed in the Paleozoic origins of major metazoan body plans, or in the origin of tetrapods. High rhomaleosaurid diversity immediately following the Triassic-Jurassic boundary supports the gradual model of Late Triassic extinctions, mostly predating the boundary itself. Increase in both maximum and minimum body length early in plesiosaurian history suggests a driven evolutionary trend. However, Maximum-likelihood models suggest only passive expansion into higher body size categories.

Pelagic larval duration predicts extinction risk in a freshwater fish clade

OpenAIRE

Douglas, Morgan; Keck, Benjamin P.; Ruble, Crystal; Petty, Melissa; Shute, J. R.; Rakes, Patrick; Hulsey, C. Darrin

2013-01-01

Pelagic larval duration (PLD) can influence evolutionary processes ranging from dispersal to extinction in aquatic organisms. Using estimates of PLD obtained from species of North American darters (Percidae: Etheostomatinae), we demonstrate that this freshwater fish clade exhibits surprising variation in PLD. Comparative analyses provide some evidence that higher stream gradients favour the evolution of shorter PLD. Additionally, similar to patterns in the marine fossil record in which lower ...

Nutrient reduction and climate change cause a potential shift from pelagic to benthic pathways in a eutrophic marine ecosystem

DEFF Research Database (Denmark)

Lindegren, Martin; Blenckner, T.; Stenseth, N.C.

2012-01-01

The degree to which marine ecosystems may support the pelagic or benthic food chain has been shown to vary across natural and anthropogenic gradients for e.g., in temperature and nutrient availability. Moreover, such external forcing may not only affect the flux of organic matter but could trigger...... variables across all trophic levels, we here propose a potential regime shift from pelagic to benthic regulatory pathways; a possible first sign of recovery from eutrophication likely triggered by drastic nutrient reductions (involving both nitrogen and phosphorus), in combination with climate...

Seasonal changes in the δ13C and δ15N signatures of the Lago Maggiore pelagic food web

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Marina MANCA

2011-08-01

Full Text Available Seasonal variation in the relative contributions of littoral and pelagic food sources to the diets of open-water zooplankton and subsequent changes in their trophic positions were investigated with carbon and nitrogen Stable Isotope Analysis (SIA. We selected three open water stations as truly pelagic, but also influenced by littoral and riverine carbon sources. During each of the four seasons, integrated pelagic zooplankton samples were collected over 0-50 m depth intervals at each site along with seston in the size range 1.2-76 μm. In addition, vertical temperature profiles were measured. Littoral benthos from three sites along the main longitudinal axis of the lake was sampled to serve as a reference for tracing Lago Maggiore's littoral carbon isotopic signature. Among stations differences in δ13C and δ15N signatures of the different components of the pelagic food web, from seston to predatory zooplankton, were statistically non significant, thus confirming that allochthonous input may become important only after exceptional rainfall events. Changes in the δ13C pelagic baseline mirrored mean water temperature (0-50 m seasonal changes. Similarly to Lake Geneva, they were likely driven by changes in carbon sources for phytoplankton growth during stratification and vertical water mixing. Differently from what observed for the other taxa, the role of littoral food sources was far from negligible (>50% for diaptomids during winter and spring. We do not know however, whether such a result could be at least partially attributed to the heavy infestation by algal epibionts, or was consequent to the fact that these zooplankters may carry littoral carbon to the pelagial via horizontal migration. In winter, Bythotrephes longimanus was able to prey on Cyclops, thus occupying a trophic position comparable to that of planktivorous fish. Such a result confirms an ability of this visual, invertebrate predator to compete with young zooplanktivorous fish

Transuranic concentrations in reef and pelagic fish from the Marshall Islands

International Nuclear Information System (INIS)

Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Jokela, T.A.

1980-09-01

Concentrations of /sup 239 + 240/Pu are reported in tissues of several species of reef and pelagic fish caught at 14 different atolls in the northern Marshall Islands. Several regularities that are species dependent are evident in the distribution of /sup 239 + 240/Pu among different body tissues. Concentrations in liver always exceeded those in bone and concentrations were lowest in the muscle of all fish analyzed. A progressive discrimination against /sup 239 + 240/Pu was observed at successive trophic levels at all atolls except Bikini and Enewetak, where it was difficult to conclude if any real difference exists between the average concentration factor for /sup 239 + 240/Pu among all fish, which include bottom feeding and grazing herbivores, bottom feeding carnivores, and pelagic carnivores from different atoll locations. The average concentration of /sup 239 + 240/Pu in the muscle of surgeonfish from Bikini and Enewetak was not significantly different from the average concentrations determined in these fish at the other, lesser contaminated atolls. Concentrations among all 3rd, 4th, and 5th trophic level species are highest at Bikini where higher environmental concentrations are found. The reasons for the anomalously low concentrations in herbivores from Bikini and Enewetak are not known

Migration and wintering sites of Pelagic Cormorants determined by satellite telemetry

Science.gov (United States)

Hatch, Shyla A.; Gill, V.A.; Mulcahy, D.M.

2011-01-01

Factors affecting winter survival may be key determinants of status and population trends of seabirds, but connections between breeding sites and wintering areas of most populations are poorly known. Pelagic Cormorants (Phalacrocorax pelagicus; N= 6) surgically implanted with satellite transmitters migrated from a breeding colony on Middleton Island, northern Gulf of Alaska, to wintering sites in southeast Alaska and northern British Columbia. Winter locations averaged 920 km (range = 600-1190 km) from the breeding site. Migration flights in fall and spring lasted ???5 d in four instances. After reaching wintering areas, cormorants settled in narrowly circumscribed inshore locations (~10-km radius) and remained there throughout the nonbreeding period (September- March). Two juveniles tagged at the breeding colony as fledglings remained at their wintering sites for the duration of the tracking interval (14 and 22 mo, respectively). Most cormorants used multiple sites within their winter ranges for roosting and foraging. Band recoveries show that Pelagic Cormorants in southern British Columbia and Washington disperse locally in winter, rather than migrating like the cormorants in our study. Radio-tagging and monitoring cormorants and other seabirds from known breeding sites are vital for understanding migratory connectivity and improving conservation strategies for local populations. ?? 2011 The Authors. Journal of Field Ornithology ?? 2011 Association of Field Ornithologists.

Transuranic concentrations in reef and pelagic fish from the Marshall Islands

International Nuclear Information System (INIS)

Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Jokela, T.A.

1981-01-01

Concentrations of sup(239+240)Pu are reported in tissues of several species of reef and pelagic fish caught at 14 different atolls in the northern Marshall Islands. Several regularities that are species dependent are evident in the distribution of sup(239+240)Pu among different body tissues. Concentrations in liver always exceeded those in bone and concentrations were lowest in the muscle of all fish analysed. A progressive discrimination against sup(239+240)Pu was observed at successive trophic levels at all atolls except Bikini and Enewetak, where it was difficult to conclude if any real difference exists between the average concentration factor for sup(239+240)Pu among all fish, which include bottom-feeding and grazing herbivores, bottom-feeding carnivores and pelagic carnivores from different atoll locations. The average concentration of sup(239+240)Pu in the muscle of surgeonfish from Bikini and Enewetak was not significantly different from the average concentrations determined in these fish at the other lesser contaminated atolls. Concentrations among all 3rd, 4th and 5th trophic level species are highest at Bikini where higher environmental concentrations are found. The reasons for the anomalously low concentrations in herbivores from Bikini and Enewetak are not known. (author)

76 FR 60444 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Coastal Migratory Pelagic...

Science.gov (United States)

2011-09-29

..., cobia, cero, little tunny, dolphin, and bluefish (Gulf only). At present, only king mackerel, Spanish... bluefish from the Coastal Migratory Pelagic FMP. The Councils and NMFS have determined these species are...

Assimilation of diazotrophic nitrogen into pelagic food webs.

Science.gov (United States)

Woodland, Ryan J; Holland, Daryl P; Beardall, John; Smith, Jonathan; Scicluna, Todd; Cook, Perran L M

2013-01-01

The fate of diazotrophic nitrogen (N(D)) fixed by planktonic cyanobacteria in pelagic food webs remains unresolved, particularly for toxic cyanophytes that are selectively avoided by most herbivorous zooplankton. Current theory suggests that N(D) fixed during cyanobacterial blooms can enter planktonic food webs contemporaneously with peak bloom biomass via direct grazing of zooplankton on cyanobacteria or via the uptake of bioavailable N(D) (exuded from viable cyanobacterial cells) by palatable phytoplankton or microbial consortia. Alternatively, N(D) can enter planktonic food webs post-bloom following the remineralization of bloom detritus. Although the relative contribution of these processes to planktonic nutrient cycles is unknown, we hypothesized that assimilation of bioavailable N(D) (e.g., nitrate, ammonium) by palatable phytoplankton and subsequent grazing by zooplankton (either during or after the cyanobacterial bloom) would be the primary pathway by which N(D) was incorporated into the planktonic food web. Instead, in situ stable isotope measurements and grazing experiments clearly documented that the assimilation of N(D) by zooplankton outpaced assimilation by palatable phytoplankton during a bloom of toxic Nodularia spumigena Mertens. We identified two distinct temporal phases in the trophic transfer of N(D) from N. spumigena to the plankton community. The first phase was a highly dynamic transfer of N(D) to zooplankton with rates that covaried with bloom biomass while bypassing other phytoplankton taxa; a trophic transfer that we infer was routed through bloom-associated bacteria. The second phase was a slowly accelerating assimilation of the dissolved-N(D) pool by phytoplankton that was decoupled from contemporaneous variability in N. spumigena concentrations. These findings provide empirical evidence that N(D) can be assimilated and transferred rapidly throughout natural plankton communities and yield insights into the specific processes underlying

Assimilation of diazotrophic nitrogen into pelagic food webs.

Directory of Open Access Journals (Sweden)

Ryan J Woodland

Full Text Available The fate of diazotrophic nitrogen (N(D fixed by planktonic cyanobacteria in pelagic food webs remains unresolved, particularly for toxic cyanophytes that are selectively avoided by most herbivorous zooplankton. Current theory suggests that N(D fixed during cyanobacterial blooms can enter planktonic food webs contemporaneously with peak bloom biomass via direct grazing of zooplankton on cyanobacteria or via the uptake of bioavailable N(D (exuded from viable cyanobacterial cells by palatable phytoplankton or microbial consortia. Alternatively, N(D can enter planktonic food webs post-bloom following the remineralization of bloom detritus. Although the relative contribution of these processes to planktonic nutrient cycles is unknown, we hypothesized that assimilation of bioavailable N(D (e.g., nitrate, ammonium by palatable phytoplankton and subsequent grazing by zooplankton (either during or after the cyanobacterial bloom would be the primary pathway by which N(D was incorporated into the planktonic food web. Instead, in situ stable isotope measurements and grazing experiments clearly documented that the assimilation of N(D by zooplankton outpaced assimilation by palatable phytoplankton during a bloom of toxic Nodularia spumigena Mertens. We identified two distinct temporal phases in the trophic transfer of N(D from N. spumigena to the plankton community. The first phase was a highly dynamic transfer of N(D to zooplankton with rates that covaried with bloom biomass while bypassing other phytoplankton taxa; a trophic transfer that we infer was routed through bloom-associated bacteria. The second phase was a slowly accelerating assimilation of the dissolved-N(D pool by phytoplankton that was decoupled from contemporaneous variability in N. spumigena concentrations. These findings provide empirical evidence that N(D can be assimilated and transferred rapidly throughout natural plankton communities and yield insights into the specific processes

Human paleoecological integration in subarctic eastern Beringia

Science.gov (United States)

Lanoë, François B.; Reuther, Joshua D.; Holmes, Charles E.; Hodgins, Gregory W. L.

2017-11-01

We contribute to the understanding of megafauna extinction and human dispersal in subarctic eastern Beringia by focusing on changes in the trophic dynamics of the large mammal community as well as the ecological role of humans as a predator and competitor. We reconstruct habitat use by megafauna and humans throughout the Pleistocene-Holocene boundary based on zooarchaeological data and stable isotope ratios of collagen. Our results are consistent with habitat heterogeneity and availability being important factors in the changing abundance of large herbivores. We argue that an increase in herbivore diversity and biomass at the beginning of the Bølling-Allerød interstadial and a relative lack of competitors favored the initial human colonization of subarctic eastern Beringia. As herbivore resources dwindled later in the Late Glacial, people increasingly relied on bison and wapiti. By efficiently extracting some of the highest-ranked resources in the landscape, people are likely to have contributed to the trophic displacement or regional extirpation of other large predators. The ecological patterns that we observe in subarctic eastern Beringia are consistent with a mixture of both top-down and bottom-up controls over biotic turnover.

Predictability of summer extreme precipitation days over eastern China

Science.gov (United States)

Li, Juan; Wang, Bin

2017-08-01

Extreme precipitation events have severe impacts on human activity and natural environment, but prediction of extreme precipitation events remains a considerable challenge. The present study aims to explore the sources of predictability and to estimate the predictability of the summer extreme precipitation days (EPDs) over eastern China. Based on the region- and season-dependent variability of EPDs, all stations over eastern China are divided into two domains: South China (SC) and northern China (NC). Two domain-averaged EPDs indices during their local high EPDs seasons (May-June for SC and July-August for NC) are therefore defined. The simultaneous lower boundary anomalies associated with each EPDs index are examined, and we find: (a) the increased EPDs over SC are related to a rapid decaying El Nino and controlled by Philippine Sea anticyclone anomalies in May-June; (b) the increased EPDs over NC are accompanied by a developing La Nina and anomalous zonal sea level pressure contrast between the western North Pacific subtropical high and East Asian low in July-August. Tracking back the origins of these boundary anomalies, one or two physically meaningful predictors are detected for each regional EPDs index. The causative relationships between the predictors and the corresponding EPDs over each region are discussed using lead-lag correlation analyses. Using these selected predictors, a set of Physics-based Empirical models is derived. The 13-year (2001-2013) independent forecast shows significant temporal correlation skills of 0.60 and 0.74 for the EPDs index of SC and NC, respectively, providing an estimation of the predictability for summer EPDs over eastern China.

STATUS OF SMALL PELAGIC FISHERY IN THE MAKASSAR STRAIT BASED AT THE NORTHERN PART OF JAVA

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Sri Turni Hartati

2016-12-01

Full Text Available The coastal of Makassar Strait is one of main fishing grounds for purse seine vessels from northern part of Java which based at the following landing sites, i.e. Pekalongan, Tegal and Juwana. The purse seine fishery predominantly targets small pelagic fish. This paper attempts to present the current condition of small pelagic fishery in the Makassar Strait. Catch and effort (trip data between 2004 and 2011 from the three landing sites were used to estimate Maximum Sustainable Yield (MSY using Schaefer & Fox models. The results showed a decreasing trend in the catch rate, from 30.83 tons/trip in 2004 to 12.27 tons/trip in 2011. The estimated MSY is at the range of 34,705- 37,930 tons with optimum efforts for 2,234-2,500 purse seine trips. Thus the level of purse seine fishing effort in 2011, i.e. 3,078 trips, was exceeding the optimum effort. The decreasing trend in the catch rate may indicate overfishing is occurring between 2004 and 2011. For management of the small pelagic fisheries in the waters of Makassar Strait, important action recommended is fishing effort restrictions. The effort allowed would be only in the range of 2,234-2,500 purse seine trips, and the fishing capacity needs to be controled.

Real-time distribution of pelagic fish: combining hydroacoustics, GIS and spatial modelling at a fine spatial scale.

Science.gov (United States)

Muška, Milan; Tušer, Michal; Frouzová, Jaroslava; Mrkvička, Tomáš; Ricard, Daniel; Seďa, Jaromír; Morelli, Federico; Kubečka, Jan

2018-03-29

Understanding spatial distribution of organisms in heterogeneous environment remains one of the chief issues in ecology. Spatial organization of freshwater fish was investigated predominantly on large-scale, neglecting important local conditions and ecological processes. However, small-scale processes are of an essential importance for individual habitat preferences and hence structuring trophic cascades and species coexistence. In this work, we analysed the real-time spatial distribution of pelagic freshwater fish in the Římov Reservoir (Czechia) observed by hydroacoustics in relation to important environmental predictors during 48 hours at 3-h interval. Effect of diurnal cycle was revealed of highest significance in all spatial models with inverse trends between fish distribution and predictors in day and night in general. Our findings highlighted daytime pelagic fish distribution as highly aggregated, with general fish preferences for central, deep and highly illuminated areas, whereas nighttime distribution was more disperse and fish preferred nearshore steep sloped areas with higher depth. This turnover suggests prominent movements of significant part of fish assemblage between pelagic and nearshore areas on a diel basis. In conclusion, hydroacoustics, GIS and spatial modelling proved as valuable tool for predicting local fish distribution and elucidate its drivers, which has far reaching implications for understanding freshwater ecosystem functioning.

Arsenic, cadmium, lead and mercury in canned sardines commercially available in eastern Kentucky, USA

International Nuclear Information System (INIS)

Shiber, John G.

2011-01-01

Research highlights: → Total As, Cd, Pb and Hg in canned sardines within ranges of other studies. → As highest in samples from Norway (1.87 μg/g) and Thailand (1.63 μg/g). → Cd highest in Moroccan (0.07 μg/g), Pb in Canadian (0.27 μg/g); Hg not detected. → Lack of established limits for As and Cd in fish restricts interpretation of results. → Rise of small pelagics in human diet warrants more scrutiny on their metal content. - Abstract: Seventeen samples of canned sardines, originating from six countries and sold in eastern Kentucky, USA, were analyzed in composites of 3-4 fish each for total arsenic (As), cadmium (Cd) and lead (Pb) by graphite furnace atomic absorption spectrophotometry (AAS) and for mercury (Hg) by thermal decomposition amalgamation and AAS. Results in μg/g wet: As 0.49-1.87 (mean: 1.06), Cd < 0.01-0.07 (0.03), Pb < 0.06-0.27 (0.11), Hg ND < 0.09. Values fall generally within readings reported by others, but no internationally agreed upon guidelines have yet been set for As or Cd in canned or fresh fish. The incidence of cancers and cardiovascular diseases associated with As ingestion is extraordinarily high here. With the role of food-borne As in human illness presently under scrutiny and its maximum allowable limits in fish being reviewed, more studies of this nature are recommended, especially considering the potential importance of small pelagic fishes as future seafood of choice.

Long-term, Ecosystem-Scale Changes in the Southern Benguela Marine Pelagic Social-Ecological System: Interaction of Natural and Human Drivers

Directory of Open Access Journals (Sweden)

Astrid Jarre

2013-12-01

Full Text Available South Africa's small pelagics fishery is currently the largest in volume and second largest in value in the southern Benguela. It exploits short-lived, small pelagic fishes such as anchovy (for reduction into fish meal and oil and sardine (for reduction as well as human consumption through canned products, and to a lesser extent redeye round herring and mesopelagics, largely for reduction. We explore the recent history (1940s to present of the social-ecological system around this fishery. The natural subsystem, at the scales of the ocean environment and the ecosystem, is characterized by high interannual and documented decadal-scale variability. We characterize the human social subsystem at the scales of the fishing industry, legislation, and west coast fishing towns, and demonstrate interdependencies between the natural and social subsystems by following system-scale changes. The pelagic fishing industry has evolved to deal with variability through consolidation, diversification, and range expansion. Legislation has increasingly looked for conservation of the resource while ensuring economic viability of the industry, and hence factory- and vessel-related jobs. Fishing communities under apartheid stayed largely dependent on company-generated infrastructure, combining seasonal employment in the fishing factories with inshore fishing, targeting rock lobster and line fish. While the pelagic industry persisted and communities survived, the resource base for both offshore and inshore fisheries gradually eroded. The advent of democracy in the mid-1990s brought allocation of long-term fishing rights to individuals or companies under conditions of depleted inshore resources aggravated by a shift in the distribution of pelagic fish away from the west coast towards the Cape south coast in the second half of the 1990s. The resultant loss of employment and fishing rights in the inshore has generated community coping strategies that include poaching and

Chasing after Non-cyanobacterial Nitrogen Fixation in Marine Pelagic Environments

Directory of Open Access Journals (Sweden)

Pia H. Moisander

2017-09-01

Full Text Available Traditionally, cyanobacterial activity in oceanic photic layers was considered responsible for the marine pelagic dinitrogen (N2 fixation. Other potentially N2-fixing bacteria and archaea have also been detected in the pelagic water column, however, the activity and importance of these non-cyanobacterial diazotrophs (NCDs remain poorly constrained. In this perspective we summarize the N2 fixation rates from recently published studies on photic and aphotic layers that have been attributed to NCD activity via parallel molecular measurements, and discuss the status, challenges, and data gaps in estimating non-cyanobacterial N2 fixation NCNF in the ocean. Rates attributed to NCNF have generally been near the detection limit thus far (<1 nmol N L−1 d−1. Yet, if considering the large volume of the dark ocean, even low rates of NCNF could make a significant contribution to the new nitrogen input to the ocean. The synthesis here shows that nifH transcription data for NCDs have been reported in only a few studies where N2 fixation rates were detected in the absence of diazotrophic cyanobacteria. In addition, high apparent diversity and regional variability in the NCDs complicate investigations of these communities. Future studies should focus on further investigating impacts of environmental drivers including oxygen, dissolved organic matter, and dissolved inorganic nitrogen on NCNF. Describing the ecology of NCDs and accurately measuring NCNF rates, are critical for a future evaluation of the contribution of NCNF to the marine nitrogen budget.

Interested in Pelagic Food Webs? BCO-DMO has your Data.

Science.gov (United States)

Chandler, C. L.; Groman, R. C.; Kinkade, D.; Rauch, S.; Allison, M. D.; Gegg, S. R.; Shepherd, A.; Wiebe, P. H.; Glover, D. M.

2016-02-01

Interdisciplinary research collaborations that address complex, global research themes such as the interactive effects of global warming and studies of pelagic food webs require access to a broad range of data types from all disciplines of oceanography, from all platforms (e.g. ships, gliders, floats, moorings), with the in situ observations complementing and being complemented by laboratory and model results. In an effort to build a comprehensive database of marine ecosystem research data, the National Science Foundation (NSF) funded the Biological and Chemical Oceanography Data Management Office (BCO-DMO; bco-dmo.org) to support the data management requirements of investigators funded by the NSF's Polar Programs (PLR) and Biological and Chemical Oceanography Sections (OCE). Since 2006, investigators funded by NSF PLR and OCE have been working with support from BCO-DMO data scientists, to build a data system that now includes the full range of ocean biogeochemistry data resulting from decades of research. In addition to data from recently funded PIs, the BCO-DMO data system also serves data from legacy programs (e.g. US Joint Global Ocean Flux Study and US Global Ocean Ecosystem Dynamics). The data are open-access, available for download in a variety of user-selectable formats, and accompanied by sufficient documentation to enable re-use. This presentation will highlight the diversity of data available from the BCO-DMO system and demonstrate some of the features that enable discovery, access and download of data relevant to studies of pelagic food webs.

The importance of chemical buffering for pelagic and benthic colonization in acidic waters

International Nuclear Information System (INIS)

Nixdorf, B.; Lessmann, D.; Steinberg, C. E. W.

2003-01-01

In poorly buffered areas acidification may occur for two reasons: through atmospheric deposition of acidifying substances and - in mining districts - through pyrite weathering. These different sources of acidity lead to distinct clearly geochemistry in lakes and rivers. In general, the geochemistry is the major determinant for the planktonic composition of the acidified water bodies, whereas the nutrient status mainly determines the level of biomass. A number of acidic mining lakes in Eastern Germany have to be neutralized to meet the water quality goals of the European Union Directives and to overcome the ecological degradation. This neutralization process is limnologically a short-term maturation of lakes, which permits biological succession to overcome two different geochemical buffer systems. First, the iron buffer system characterizes an initial state, when colonization starts: there is low organismic diversity and productivity, clear net heterotrophy in most cases. Organic carbon that serves as fuel for the food web derives mainly from allochthonous sources. In the second, less acidic state aluminum is the buffer. This state is found exceptionally among the hard water mining lakes, often as a result of deposition of acidifying substances onto soft water systems. Colonization in aluminum-buffered lakes is more complex and controlled by the sensitivity of the organisms towards both, protons and inorganic reactive aluminum species. In soft-water systems, calcium may act as antidote against acid and aluminum; however, this function is lost in hard water post mining lakes of similar proton concentrations. Nutrient limitations may occur, but these do not usually control qualitative and quantitative plankton composition. In these lakes, total pelagic biomass is controlled by the bioavailability of nutrients, particularly phosphorus

Sex, sex-ratios, and the dynamics of pelagic copepod populations

DEFF Research Database (Denmark)

Kiørboe, Thomas

2006-01-01

equal adult sex ratios in field populations. Winter population densities are orders of magnitude less than the critical population density required for population persistence, but populations survive winter seasons as resting eggs in the sediment. Population growth in these species is potentially high...... because they have on average a factor of 2 higher egg production rates than other pelagic copepods. Secondly, other copepods require only one mating to stay fertile, and populations of these species have strongly female-skewed adult sex-ratios in field populations. Resting eggs have not been described...

Structure and phylogeography of two tropical predators, spinner (Stenella longirostris) and pantropical spotted (S. attenuata) dolphins, from SNP data

Science.gov (United States)

Morin, Phillip A.

2018-01-01

Little is known about global patterns of genetic connectivity in pelagic dolphins, including how circumtropical pelagic dolphins spread globally following the rapid and recent radiation of the subfamily delphininae. In this study, we tested phylogeographic hypotheses for two circumtropical species, the spinner dolphin (Stenella longirostris) and the pantropical spotted dolphin (Stenella attenuata), using more than 3000 nuclear DNA single nucleotide polymorphisms (SNPs) in each species. Analyses for population structure indicated significant genetic differentiation between almost all subspecies and populations in both species. Bayesian phylogeographic analyses of spinner dolphins showed deep divergence between Indo-Pacific, Atlantic and eastern tropical Pacific Ocean (ETP) lineages. Despite high morphological variation, our results show very close relationships between endemic ETP spinner subspecies in relation to global diversity. The dwarf spinner dolphin is a monophyletic subspecies nested within a major clade of pantropical spinner dolphins from the Indian and western Pacific Ocean populations. Population-level division among the dwarf spinner dolphins was detected—with the northern Australia population being very different from that in Indonesia. In contrast to spinner dolphins, the major boundary for spotted dolphins is between offshore and coastal habitats in the ETP, supporting the current subspecies-level taxonomy. Comparing these species underscores the different scale at which population structure can arise, even in species that are similar in habitat (i.e. pelagic) and distribution. PMID:29765639

Effect of Macondo Prospect 252 Oil on Microbiota Associated with Pelagic Sargassum in the Northern Gulf of Mexico.

Science.gov (United States)

Torralba, Manolito G; Franks, James S; Gomez, Andres; Yooseph, Shibu; Nelson, Karen E; Grimes, D Jay

2017-01-01

The environmental impact of major oil spills on marine microorganisms has yet to be thoroughly investigated using molecular biology techniques. The Deepwater Horizon (DWH) drilling rig explosion of 2010 affected an approximately 176,000 km 2 surface area of the Gulf of Mexico (GOM) when an estimated 210 million gallons of oil from the Macondo Prospect spilled into the environment. Pelagic Sargassum, a complex of two surface drifting species (Sargassum natans and Sargassum fluitans) of marine brown macroalgae and a critically important habitat in the GOM ecosystem, was suffused by Macondo Prospect 252 oil released during the DWH event. Using 16S rRNA PCR and Roche 454 pyrosequencing, the effect of the oil on the bacterial population associated with pelagic Sargassum and contiguous waters was examined by comparing sequence data generated from samples collected from oiled and non-oiled locations in the northern GOM. Sequence data showed similar microbial composition in Sargassum regardless of exposure to oil primarily dominated by five phyla; Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, and unclassified bacteria. The microbial composition in water samples was significantly less diverse than for Sargassum and consisted primarily of Proteobacteria, Firmicutes, and Bacteroidetes. Due to the evenly distributed abundance of microbial species on oiled and non-oiled pelagic Sargassum, study findings indicate that DWH spilled oil had minimal effect on the composition and diversity of the microbial community associated with Sargassum and contiguous waters. However, higher abundances of Sulfitobacter and one species of Psychrobacter were found in oiled water samples when compared to non-oiled water samples indicating some effect of DHW oil in the microbial composition of seawater. Though there are a number of marine studies using molecular biology approaches, this is the first molecular examination of the impact of the DWH oil spill on bacterial communities

Multilocus phylogeny, divergence times, and a major role for the benthic-to-pelagic axis in the diversification of grunts (Haemulidae).

Science.gov (United States)

Tavera, Jose; Acero P, Arturo; Wainwright, Peter C

2018-04-01

We present a phylogenetic analysis with divergence time estimates, and an ecomorphological assessment of the role of the benthic-to-pelagic axis of diversification in the history of haemulid fishes. Phylogenetic analyses were performed on 97 grunt species based on sequence data collected from seven loci. Divergence time estimation indicates that Haemulidae originated during the mid Eocene (54.7-42.3 Ma) but that the major lineages were formed during the mid-Oligocene 30-25 Ma. We propose a new classification that reflects the phylogenetic history of grunts. Overall the pattern of morphological and functional diversification in grunts appears to be strongly linked with feeding ecology. Feeding traits and the first principal component of body shape strongly separate species that feed in benthic and pelagic habitats. The benthic-to-pelagic axis has been the major axis of ecomorphological diversification in this important group of tropical shoreline fishes, with about 13 transitions between feeding habitats that have had major consequences for head and body morphology. Copyright © 2017 Elsevier Inc. All rights reserved.

A case for redefining the boundaries of the Mesoamerican Reef Ecoregion

Science.gov (United States)

Chollett, Iliana; Garavelli, Lysel; Holstein, Daniel; Cherubin, Laurent; Fulton, Stuart; Box, Stephen J.

2017-12-01

The Mesoamerican Reef (MAR) is an interconnected system that supports the local economies of four countries through the provision of seafood and tourism. Considerable financial, research and management effort has been invested in this priority ecoregion, whose boundaries were defined more than 18 yr ago based on best available data on oceanographic patterns, reef and watershed distribution. The long-term persistence of the MAR depends, however, on ensuring that all of its constituent parts are appropriately managed, and the current boundaries may not respond to this need. Here we assess the suitability of the current boundaries of the MAR using information on physical environments and larval connectivity of three key species. Our research indicates the boundaries of the ecoregion require an adjustment, as the exclusion of key areas in eastern Honduras might jeopardize the persistence of the entire network of connected reefs, and areas in northern Yucatan belong to a different environmental regime and may require different management strategies.

Detection of pelagic habitat hotspots for skipjack tuna in the Gulf of Bone-Flores Sea, southwestern Coral Triangle tuna, Indonesia.

Science.gov (United States)

Zainuddin, Mukti; Farhum, Aisjah; Safruddin, Safruddin; Selamat, Muhammad Banda; Sudirman, Sudirman; Nurdin, Nurjannah; Syamsuddin, Mega; Ridwan, Muhammad; Saitoh, Sei-Ichi

2017-01-01

Using remote sensing of sea surface temperature (SST), sea surface height anomaly (SSHA) and chlorophyll-a (Chl-a) together with catch data, we investigated the detection and persistence of important pelagic habitat hotspots for skipjack tuna in the Gulf of Bone-Flores Sea, Indonesia. We analyzed the data for the period between the northwest and southeast monsoon 2007-2011. A pelagic hotspot index was constructed from a model of multi-spectrum satellite-based oceanographic data in relation to skipjack fishing performance. Results showed that skipjack catch per unit efforts (CPUEs) increased significantly in areas of highest pelagic hotspot indices. The distribution and dynamics of habitat hotspots were detected by the synoptic measurements of SST, SSHA and Chl-a ranging from 29.5° to 31.5°C, from 2.5 to 12.5 cm and from 0.15 to 0.35 mg m-3, respectively. Total area of hotspots consistently peaked in May. Validation of skipjack CPUE predicted by our model against observed data from 2012 was highly significant. The key pelagic habitat corresponded with the Chl-a front, which could be related to the areas of relatively high prey abundance (enhanced feeding opportunity) for skipjack. We found that the area and persistence of the potential skipjack habitat hotspots for the 5 years were clearly identified by the 0.2 mg m-3 Chl-a isopleth, suggesting that the Chl-a front provides a key oceanographic indicator for global understanding on skipjack tuna habitat hotspots in the western tropical Pacific Ocean, especially within Coral Triangle tuna.

Synergistic Interactions within a Multispecies Biofilm Enhance Individual Species Protection against Grazing by a Pelagic Protozoan

DEFF Research Database (Denmark)

Raghupathi, Prem Krishnan; Liu, Wenzheng; Sabbe, Koen

2018-01-01

of a multispecies bacterial biofilm subject to grazing by a pelagic protozoan predator were investigated. To this end, a mono and multispecies biofilms of four bacterial soil isolates, namely Xanthomonas retroflexus, Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus, were...

Association of whale sharks (Rhincodon typus) with thermo-biological frontal systems of the eastern tropical Pacific.

Science.gov (United States)

Ryan, John P; Green, Jonathan R; Espinoza, Eduardo; Hearn, Alex R

2017-01-01

Satellite tracking of 27 whale sharks in the eastern tropical Pacific, examined in relation to environmental data, indicates preferential occupancy of thermo-biological frontal systems. In these systems, thermal gradients are caused by wind-forced circulation and mixing, and biological gradients are caused by associated nutrient enrichment and enhanced primary productivity. Two of the frontal systems result from upwelling, driven by divergence in the current systems along the equator and the west coast of South America; the third results from wind jet dynamics off Central America. All whale sharks were tagged near Darwin Island, Galápagos, within the equatorial Pacific upwelling system. Occupancy of frontal habitat is pronounced in synoptic patterns of shark locations in relation to serpentine, temporally varying thermal fronts across a zonal expanse > 4000 km. 80% of shark positions in northern equatorial upwelling habitat and 100% of positions in eastern boundary upwelling habitat were located within the upwelling front. Analysis of equatorial shark locations relative to thermal gradients reveals occupancy of a transition point in environmental stability. Equatorial subsurface tag data show residence in shallow, warm (>22°C) water 94% of the time. Surface zonal current speeds for all equatorial tracking explain only 16% of the variance in shark zonal movement speeds, indicating that passive drifting is not a primary determinant of movement patterns. Movement from equatorial to eastern boundary frontal zones occurred during boreal winter, when equatorial upwelling weakens seasonally. Off Peru sharks tracked upwelling frontal positions within ~100-350 km from the coast. Off Central America, the largest tagged shark (12.8 m TL) occupied an oceanic front along the periphery of the Panama wind jet. Seasonal movement from waning equatorial upwelling to productive eastern boundary habitat is consistent with underlying trophic dynamics. Persistent shallow residence in

Boundary-Layer Characteristics of Persistent Regional Haze Events and Heavy Haze Days in Eastern China

Directory of Open Access Journals (Sweden)

Peng Huaqing

2016-01-01

Full Text Available This paper analyzed the surface conditions and boundary-layer climate of regional haze events and heavy haze in southern Jiangsu Province in China. There are 5 types with the surface conditions which are equalized pressure (EQP, the advancing edge of a cold front (ACF, the base of high pressure (BOH, the backside of high pressure (BAH, the inverted trough of low pressure (INT, and saddle pressure (SAP with the haze days. At that time, 4 types are divided with the regional haze events and each of which has a different boundary-layer structure. During heavy haze, the surface mainly experiences EQP, ACF, BOH, BAH, and INT which also have different boundary-layer structures.

Gauging proximities: an inquiry into a possible nexus between Middle Eastern and Western painting

NARCIS (Netherlands)

Emir-Sayers, E.

2012-01-01

The purpose of this paper is to explore the boundaries between the Middle Eastern Miniature tradition and 20th-century Western philosophy of art. Orhan Pamuk's novel, My Name is Red, provides the initial inspiration for such a project. In order to investigate possible proximities between Middle

The uptake of macroplastic & microplastic by demersal & pelagic fish in the Northeast Atlantic around Scotland.

Science.gov (United States)

Murphy, Fionn; Russell, Marie; Ewins, Ciaran; Quinn, Brian

2017-09-15

This study reports plastic ingestion in various fish found from coastal and offshore sites in Scottish marine waters. Coastal samples consisted of three demersal flatfish species (n=128) collected from the East and West coasts of Scotland. Offshore samples consisted of 5 pelagic species and 4 demersal species (n=84) collected from the Northeast Atlantic. From the coastal fish sampled, 47.7% of the gastrointestinal tracts contained macroplastic and microplastic. Of the 84 pelagic and demersal offshore fish, only 2 (2.4%) individuals from different species had ingested plastic identified as a clear polystyrene fibre and a black polyamide fibre. The average number of plastic items found per fish from all locations that had ingested plastic was 1.8 (±1.7) with polyamide (65.3%), polyethylene terephthalate (14.4%) and acrylic (14.4%) being the three most commonly found plastics. This study adds to the existing data on macroplastic and microplastic ingestion in fish species. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Larval assemblages of large and medium-sized pelagic species in the Straits of Florida

Science.gov (United States)

Richardson, David E.; Llopiz, Joel K.; Guigand, Cedric M.; Cowen, Robert K.

2010-07-01

Critical gaps in our understanding of the distributions, interactions, life histories and preferred habitats of large and medium-size pelagic fishes severely constrain the implementation of ecosystem-based, spatially structured fisheries management approaches. In particular, spawning distributions and the environmental characteristics associated with the early life stages are poorly documented. In this study, we consider the diversity, assemblages, and associated habitat of the larvae of large and medium-sized pelagic species collected during 2 years of monthly surveys across the Straits of Florida. In total, 36 taxa and 14,295 individuals were collected, with the highest diversity occurring during the summer and in the western, frontal region of the Florida Current. Only a few species (e.g. Thunnus obesus, T. alalunga, Tetrapturus pfluegeri) considered for this study were absent. Small scombrids (e.g. T. atlanticus, Katsuwonus pelamis, Auxis spp.) and gempylids dominated the catch and were orders of magnitude more abundant than many of the rare species (e.g. Thunnus thynnus,Kajikia albida). Both constrained (CCA) and unconstrained (NMDS) multivariate analyses revealed a number of species groupings including: (1) a summer Florida edge assemblage (e.g. Auxis spp., Euthynnus alleterattus, Istiophorus platypterus); (2) a summer offshore assemblage (e.g. Makaira nigricans, T. atlanticus, Ruvettus pretiosus, Lampris guttatus); (3) an ubiquitous assemblage (e.g. K. pelamis, Coryphaena hippurus, Xiphias gladius); and (4) a spring/winter assemblage that was widely dispersed in space (e.g. trachipterids). The primary environmental factors associated with these assemblages were sea-surface temperature (highest in summer-early fall), day length (highest in early summer), thermocline depth (shallowest on the Florida side) and fluorescence (highest on the Florida side). Overall, the results of this study provide insights into how a remarkable diversity of pelagic species

The Density Jump at the Inner Core Boundary in the Eastern and Western Hemispheres

Science.gov (United States)

Krasnoshchekov, D. N.; Ovtchinnikov, V. M.

2018-02-01

The results of analysis of more than 1300 new PKiKP/PcP amplitude ratios measured in Southeast Asia and South America at the epicentral distances of 3.2°-35.2° are presented. The density jump in the Eastern Hemisphere of the Earth's inner core (IC) is 0.3 g/cm3, and it is 0.9 g/cm3 in the Western one. Taking the large discrepancy in the obtained estimates into consideration, maintenance of such large lateral variations in the mosaic properties of the IC reflecting surface requires considerable variations in the thermodynamic parameters (mostly temperature) of the inner-outer core transition. However, if the observed asymmetry in the density jump distribution is of a global character, the data presented support the translation model of the IC dynamics. This model implies IC crystallization in the Western Hemisphere and melting in the Eastern one, not vice versa, as suggested by another geodynamic model based on thermochemical convection in the outer core and the thermal balance of the core-mantle system.

Periphyton changes over 20 years of chemical recovery of Lake Orta, Italy: differential response to perturbation of littoral and pelagic communities

Directory of Open Access Journals (Sweden)

Giuseppe MORABITO

2011-08-01

Full Text Available Lake Orta, a large Italian subalpine lake, has a long history of industrial pollution by acid, ammonia, and metals. A whole-lake liming treatment in 1989-1990 led to a gradual increase in pH (from 4.4 to 7 and a concomitant decline in ammonia (from 2.5 to 0.05 mg L-1 and metal concentrations (e.g., copper: from 35 to 3 μg L-1. In this study, we examine the response of the littoral zone, in terms of chemistry and periphyton assemblages, to contamination and recovery of Lake Orta. We compare these findings with a long-term data set of chemistry and phytoplankton collected in the pelagic zone. We sampled periphyton at two sites from the liming period (1989 through 2010 when the lake approached chemical equilibrium. Chemical variables collected in the littoral zone near the periphyton samples followed the same temporal trends observed in the pelagic zone. Chlorophytes, the dominant algae in the preliming period, progressively waned after the calcium carbonate addition. Diatom importance gradually increased to reach up to 80% of the total biovolume in the most recent years. There was a clear shift in the diatom taxonomic composition over the study period. Acidophilous Pinnularia subcapitata var. hilseana and metal-tolerant Achnanthes minutissima were dominant before liming. With the progressive increase in pH and decline in metal concentrations, there was successively the dominance of Fragilaria nanoides (formerly identified as Synedra tenera and Cymbella microcephala in the transition period and of circumneutral Navicula cryptocephala, N. radiosa, and Synedra ulna in the most recent period. Pelagic diatoms were more affected than benthic diatoms by the industrial pollution and their recovery after the liming intervention was slower. Whereas present periphyton diatom assemblages are similar to those observed in nearby unpolluted Lake Mergozzo, pelagic assemblages are still in transition from severe disturbance towards characteristics reported before

Devonian/Carboniferous boundary glacioeustatic fluctuations in a platform-to-basin direction: A geochemical approach of sequence stratigraphy in pelagic settings

Czech Academy of Sciences Publication Activity Database

Bábek, O.; Kumpan, T.; Kalvoda, J.; Matys Grygar, Tomáš

2016-01-01

Roč. 337, MAY (2016), s. 81-99 ISSN 0037-0738 Institutional support: RVO:61388980 Keywords : Element geochemistry * Hangenberg event * Glacioeustasy * Devonian/Carboniferous boundary * Sedimentation rate Subject RIV: DD - Geochemistry Impact factor: 2.373, year: 2016

Pelagic habitat visualization: the need for a third (and fourth) dimension: HabitatSpace

Science.gov (United States)

Beegle-Krause, C; Vance, Tiffany; Reusser, Debbie; Stuebe, David; Howlett, Eoin

2009-01-01

Habitat in open water is not simply a 2-D to 2.5-D surface such as the ocean bottom or the air-water interface. Rather, pelagic habitat is a 3-D volume of water that can change over time, leading us to the term habitat space. Visualization and analysis in 2-D is well supported with GIS tools, but a new tool was needed for visualization and analysis in four dimensions. Observational data (cruise profiles (xo, yo, z, to)), numerical circulation model fields (x,y,z,t), and trajectories (larval fish, 4-D line) need to be merged together in a meaningful way for visualization and analysis. As a first step toward this new framework, UNIDATA’s Integrated Data Viewer (IDV) has been used to create a set of tools for habitat analysis in 4-D. IDV was designed for 3-D+time geospatial data in the meteorological community. NetCDF JavaTM libraries allow the tool to read many file formats including remotely located data (e.g. data available via OPeNDAP ). With this project, IDV has been adapted for use in delineating habitat space for multiple fish species in the ocean. The ability to define and visualize boundaries of a water mass, which meets specific biologically relevant criteria (e.g., volume, connectedness, and inter-annual variability) based on model results and observational data, will allow managers to investigate the survival of individual year classes of commercially important fisheries. Better understanding of the survival of these year classes will lead to improved forecasting of fisheries recruitment.

A new plate tectonic concept for the eastern-most Mediterranean

Science.gov (United States)

Huebscher, C.; McGrandle, A.; Scaife, G.; Spoors, R.; Stieglitz, T.

2012-04-01

Owing to the seismogenic faults bordering the Levant-Sinai realm and the discovery of giant gas reservoirs in the marine Levant Basin the scientific interest in this tectonically complex setting increased in recent years. Here we provide a new model for the Levant Basin architecture and adjacent plate boundaries emphasizing the importance of industrial seismic data for frontier research in earth science. PSDM seismics, residual gravity and depth to basement maps give a clear line of evidence that the Levant Basin, formerly considered as a single tectonic entity, is divided into two different domains. Highly stretched continental crust in the southern domain is separated from deeper and presumably Tethyan oceanic crust in the north. A transform continuing from southwest Cyprus to the Carmel Fault in northern Israel is considered as the boundary. If this interpretation holds, the Carmel-Cyprus Transform represents a yet unknown continent-ocean boundary in the eastern Mediterranean, thus adding new constrains for the Mediterranean plate tectonic puzzle. The Eratosthenes Seamount, considered as the spearhead of incipient continental collision in the eastern Mediterranean, is interpreted as a carbonate platform that developed above a volcanic basement. NW-SE trending strike-slip faults are abundant in the entire Levant region. Since this trend also shapes the topography of the Levant hinterland including Quaternary deposits their recent tectonic activity is quite likely. Thus, our study supports previous studies which attributed the evolution of submarine canyons and Holocene triggering of mass failures not only to salt tectonics or depositional processes, but also to active plate-tectonics.

Identification of fish populations with particular reference to the pelagic fish stocks of the Indian Ocean region

Digital Repository Service at National Institute of Oceanography (India)

Dwivedi, S.N.

The most essential step in any fishery management is the identification of discrete fish populations. This is particularly important for the development of Indian Ocean pelagic fisheries. The simple signal character analysis of meristic or metric...

Food consumption and daily feeding periodicity : comparison between pelagic and demersal whiting in the North Sea

DEFF Research Database (Denmark)

Pedersen, Jens

2000-01-01

composition and energy density of the prey and spatial distribution of the whiting, demonstrates the need for a sampling design that includes both pelagic and demersal layers when quantifying the food consumption of whiting.(C) 2000 The Fisheries Society of the British Isles.......Pelagic North Sea whiting Merlagius merlangus fed at night, while demersal whiting fed by day. The estimated specific daily ration ranged from 4.38 to 7.84% in 1992 and from 3.99 to 10.31% in 1993 using the in situ rate of gastric evacuation. Using Anderson's evacuation model the specific daily...... ration ranged from 0.41 to 1.66% in 1992 and from 0.78 to 1.75% in 1993. The specific daily rations were significantly different where energy density of stomach content by length class of whiting was significantly different between the two layers and years. The fact that daily ration was related to prey...

The evolution of jaw protrusion mechanics is tightly coupled to bentho-pelagic divergence in damselfishes (Pomacentridae).

Science.gov (United States)

Cooper, W James; Carter, Casey B; Conith, Andrew J; Rice, Aaron N; Westneat, Mark W

2017-02-15

Most species-rich lineages of aquatic organisms have undergone divergence between forms that feed from the substrate (benthic feeding) and forms that feed from the water column (pelagic feeding). Changes in trophic niche are frequently accompanied by changes in skull mechanics, and multiple fish lineages have evolved highly specialized biomechanical configurations that allow them to protrude their upper jaws toward the prey during feeding. Damselfishes (family Pomacentridae) are an example of a species-rich lineage with multiple trophic morphologies and feeding ecologies. We sought to determine whether bentho-pelagic divergence in the damselfishes is tightly coupled to changes in jaw protrusion ability. Using high-speed video recordings and kinematic analysis, we examined feeding performance in 10 species that include three examples of convergence on herbivory, three examples of convergence on omnivory and two examples of convergence on planktivory. We also utilized morphometrics to characterize the feeding morphology of an additional 40 species that represent all 29 damselfish genera. Comparative phylogenetic analyses were then used to examine the evolution of trophic morphology and biomechanical performance. We find that pelagic-feeding damselfishes (planktivores) are strongly differentiated from extensively benthic-feeding species (omnivores and herbivores) by their jaw protrusion ability, upper jaw morphology and the functional integration of upper jaw protrusion with lower jaw abduction. Most aspects of cranial form and function that separate these two ecological groups have evolved in correlation with each other and the evolution of the functional morphology of feeding in damselfishes has involved repeated convergence in form, function and ecology. © 2017. Published by The Company of Biologists Ltd.

Decomposition in pelagic marine ecosytems

International Nuclear Information System (INIS)

Lucas, M.I.

1986-01-01

During the decomposition of plant detritus, complex microbial successions develop which are dominated in the early stages by a number of distinct bacterial morphotypes. The microheterotrophic community rapidly becomes heterogenous and may include cyanobacteria, fungi, yeasts and bactivorous protozoans. Microheterotrophs in the marine environment may have a biomass comparable to that of all other heterotrophs and their significance as a resource to higher trophic orders, and in the regeneration of nutrients, particularly nitrogen, that support 'regenerated' primary production, has aroused both attention and controversy. Numerous methods have been employed to measure heterotrophic bacterial production and activity. The most widely used involve estimates of 14 C-glucose uptake; the frequency of dividing cells; the incorporation of 3 H-thymidine and exponential population growth in predator-reduced filtrates. Recent attempts to model decomposition processes and C and N fluxes in pelagic marine ecosystems are described. This review examines the most sensitive components and predictions of the models with particular reference to estimates of bacterial production, net growth yield and predictions of N cycling determined by 15 N methodology. Directed estimates of nitrogen (and phosphorus) flux through phytoplanktonic and bacterioplanktonic communities using 15 N (and 32 P) tracer methods are likely to provide more realistic measures of nitrogen flow through planktonic communities

76 FR 37287 - Western Pacific Pelagic Fisheries; Prohibiting Longline Fishing Within 30 nm of the Northern...

Science.gov (United States)

2011-06-27

... fleets. This rule also makes several administrative clarifications to the pelagic fishing regulations... in the area. Also, an EEZ closure will disadvantage the United States in its negotiations to renew... recommended prohibited area for longline fishing around the CNMI. This final rule also makes administrative...

Vertebrate endemism in south-eastern Africa numerically redefines a biodiversity hotspot.

Science.gov (United States)

Perera, Sandun J; ProcheŞ, Şerban; Ratnayake-Perera, Dayani; Ramdhani, Syd

2018-02-20

We use numerical methods to explore patterns of vertebrate endemism in south-eastern Africa, refining the boundaries of the intuitively-defined Maputaland-Pondoland-Albany biodiversity hotspot, also proposing a zoogeographic regionalisation. An incidence matrix of 300 vertebrate species endemic to south-eastern Africa sensu lato in 37 operational geographic units were used in (a) phenetic cluster analysis (PCA) using the algorithm of unweighted pair-group method with arithmetic averages (phenetic approach), and (b) parsimony analysis of endemicity (PAE; parsimony approach), in order to numerically evaluate the bioregional delimitations. The analyses provide a valid biogeographical entity 37% larger than the Maputaland-Pondoland-Albany hotspot, but substantially (131%) higher in vertebrate endemicity viz. the Greater Maputaland-Pondoland-Albany (GMPA) region of vertebrate endemism. South-east Africa is recognised as a dominion in the global zoogeographical area hierarchy, with subordinate units including the GMPA province. Various spatially-based measures of endemism were mapped for vertebrate species restricted to the dominion, i.e. endemic to south-eastern Africa sensu stricto. Areas and centres of endemism detected respectively from PAE and PCA, within the south-east Africa dominion also support the refined boundary of the GMPA region of endemism, which provides a better spatial conservation priority compared to the Maputaland-Pondoland-Albany hotspot. Reptiles and amphibians are found to be the main drivers of the overall pattern of endemism, while the pattern in freshwater fish is the most distinctive. Our analyses also indicate a good congruence of the centres of endemism across different terrestrial vertebrate taxa.

Impact of biology knowledge on the conservation and management of large pelagic sharks

OpenAIRE

Yokoi, Hiroki; Ijima, Hirotaka; Ohshimo, Seiji; Yokawa, Kotaro

2017-01-01

Population growth rate, which depends on several biological parameters, is valuable information for the conservation and management of pelagic sharks, such as blue and shortfin mako sharks. However, reported biological parameters for estimating the population growth rates of these sharks differ by sex and display large variability. To estimate the appropriate population growth rate and clarify relationships between growth rate and relevant biological parameters, we developed a two-sex age-str...

Occurrence of microplastics in the gastrointestinal tract of pelagic and demersal fish from the English Channel.

Science.gov (United States)

Lusher, A L; McHugh, M; Thompson, R C

2013-02-15

Microplastics are present in marine habitats worldwide and laboratory studies show this material can be ingested, yet data on abundance in natural populations is limited. This study documents microplastics in 10 species of fish from the English Channel. 504 Fish were examined and plastics found in the gastrointestinal tracts of 36.5%. All five pelagic species and all five demersal species had ingested plastic. Of the 184 fish that had ingested plastic the average number of pieces per fish was 1.90±0.10. A total of 351 pieces of plastic were identified using FT-IR Spectroscopy; polyamide (35.6%) and the semi-synthetic cellulosic material, rayon (57.8%) were most common. There was no significant difference between the abundance of plastic ingested by pelagic and demersal fish. Hence, microplastic ingestion appears to be common, in relatively small quantities, across a range of fish species irrespective of feeding habitat. Further work is needed to establish the potential consequences. Copyright © 2012 Elsevier Ltd. All rights reserved.

Catch of pelagic hauls in Mediterranean acoustic surveys: Is it the same between day and night?

Directory of Open Access Journals (Sweden)

Athanassios Machias

2013-03-01

Full Text Available Fish sampling is a critical aspect of acoustic surveys, because it is directly related to the “transformation” of echo into species biomass and subsequently affects the accuracy of acoustic estimates. In the present study, we investigated the differences between day and night sampling in a the catch composition through certain diversity indices and b the length frequency distribution of anchovy and sardine using catch data of pelagic hauls collected from four different regions of the European Mediterranean waters. In addition, the possible bias in trawl efficiency due to sampling time and the possible error introduced in acoustic estimates were investigated. No statistically significant differences were found between day and night in any of the parameters examined. The results showed that a more flexible strategy can be adopted to reduce the duration and the cost of acoustic sampling for small pelagic species. The advantages and disadvantages of the two sampling strategies are discussed.

Studies on food organisms of pelagic fishes as revealed by the 1979 North Atlantic Eel Expedition

Science.gov (United States)

Appelbaum, S.

1982-09-01

The extent to which pelagic fishes occurring in the Sargasso Sea and adjacent parts of the Atlantic prey on leptocephali (Anguilliformes) was investigated. Most of the fishes examined (c. 95%) were collected using a commercial pelagical trawl. The stomach contents of about 1000 fishes (25 species of 10 families), mostly belonging to the suborders Myctophoidei, Stomiatoidei and the order Anguilliformes, were examined. The remains of invertebrates, mainly crustaceans, molluscs, tunicates, chaetognaths, and siphonophores were found in 28.8 % of the stomachs. Fishes, mostly myctophids or fish remains, were observed in 11.2 % of the stomachs; 18.7 % contained unidentified items and 40.6 % were empty. Leptocephali ( Ariosoma spp. and Gnathophis sp.) were found in the alimentary tract of 0.5 % of the fishes examined, exclusively represented by the myctophid, Ceratoscopelus warmingii. This report indicates that the Sargasso Sea population of Anguilla leptocephali, economically the most important eel, is not seriously affected by predation of oceanic fish species considered in this study.

Trophodynamics of mercury and other trace elements in a pelagic food chain from the Baltic Sea

International Nuclear Information System (INIS)

Nfon, Erick; Cousins, Ian T.; Jaervinen, Olli; Mukherjee, Arun B.; Verta, Matti; Broman, Dag

2009-01-01

Mercury (Hg) and 13 other trace elements (Al, Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) were measured in phytoplankton, zooplankton, mysis and herring in order to examine the trophodynamics in a well-studied pelagic food chain in the Baltic Sea. The fractionation of nitrogen isotopes (δ 15 N) was used to evaluate food web structure and to estimate the extent of trophic biomagnification of the various trace elements. Trophic magnification factors (TMFs) for each trace element were determined from the slope of the regression between trace element concentrations and δ 15 N. Calculated TMFs showed fundamental differences in the trophodynamics of the trace elements in the pelagic food chain studied. Concentrations of Al, Fe, Ni, Zn, Pb and Cd showed statistically significant decreases (TMF 1) in concentration with trophic level i.e. Hg biomagnifies in this Baltic food chain. The estimated TMF for Hg in this food chain was comparable to TMFs observed elsewhere for diverse food chains and locations.

Computation of radiation dose rate to non-human biota (Benthic and pelagic) from Nat.210Po

International Nuclear Information System (INIS)

Kamat, Rupali C.K.; Suresh, Sugandhi; Joshi, Vikram; Pulhan, Vandana

2018-01-01

Natural and anthropogenic factors are accountable for inclusion of radioactivity into the biota (flora and fauna). Among natural radionuclides 210 Po (t 1/2 =138 days) acquires importance due to it high radiotoxicity, with alpha particle energy of 5.3 MeV. It is a main contributor (90%) to the natural radiation dose received by most marine organisms and also to critical group doses from seafood consumption. Radioprotection in the past focused only on mankind with the assumption that human protection confers protection of non-human biota. However, in recent years International Commission on Radiological Protection has focused on protection of non-human biota. Radiological dose assessment to the biota is a challenging task and is an important issue of radiation protection. In line with this, the data generated in the present work is the baseline data to examine radiation dose due to naturally occurring 210 Po to the native marine species (benthic and pelagic) of the area rich in benthic and pelagic communities

Intergenerational communication satisfaction and age boundaries: comparative middle eastern data.

Science.gov (United States)

Giles, Howard; Khajavy, Gholam Hassan; Choi, Charles W

2012-12-01

Guided by the communicative predicative model of aging, American and Iranian young adults' perceptions of communication with their peers, middle-aged and elderly adults were examined; subjective boundaries for these age categories were also explored. As age of target increased, so did attributions of benevolence, norms of politeness and deference, and communicative respect and avoidance; conversely, attributions of personal vitality and communication satisfaction decreased linearly. Path analysis was also adopted to examine the simultaneous relationships between the variables under study, and ultimately with cultural caveats largely supported, a hypothesized model was derived. The data were discussed in terms of their yielding refinements and elaborations to the communicative predicament and enhancement models of aging.

Impact of biology knowledge on the conservation and management of large pelagic sharks.

Science.gov (United States)

Yokoi, Hiroki; Ijima, Hirotaka; Ohshimo, Seiji; Yokawa, Kotaro

2017-09-06

Population growth rate, which depends on several biological parameters, is valuable information for the conservation and management of pelagic sharks, such as blue and shortfin mako sharks. However, reported biological parameters for estimating the population growth rates of these sharks differ by sex and display large variability. To estimate the appropriate population growth rate and clarify relationships between growth rate and relevant biological parameters, we developed a two-sex age-structured matrix population model and estimated the population growth rate using combinations of biological parameters. We addressed elasticity analysis and clarified the population growth rate sensitivity. For the blue shark, the estimated median population growth rate was 0.384 with a range of minimum and maximum values of 0.195-0.533, whereas those values of the shortfin mako shark were 0.102 and 0.007-0.318, respectively. The maturity age of male sharks had the largest impact for blue sharks, whereas that of female sharks had the largest impact for shortfin mako sharks. Hypotheses for the survival process of sharks also had a large impact on the population growth rate estimation. Both shark maturity age and survival rate were based on ageing validation data, indicating the importance of validating the quality of these data for the conservation and management of large pelagic sharks.

Mass fluxes in the Canary Basin (eastern boundary of the North Atlantic subtropical gyre)

Science.gov (United States)

Burgoa, N.; Machin, F.; Marrero-Díaz, Á.; Rodríguez-Santana, Á.; Martínez-Marrero, A.

2017-12-01

The circulation patterns in the Canary Basin are examined with hydrographic data from two cruises carried out in 2002 and 2003 in the eastern boundary of the North Atlantic subtropical gyre (21-27.5ºN, 17.5-26ºW). These cruises were part of the COCA Project (Coastal-Ocean Carbon Exchange in the Canary Region). First we estimate the geostrophic flow within a closed box divided into 12 layers of neutral density surfaces using the thermal wind equation. The geostrophic velocities are initially referenced to a selected neutral surface previously analyzed in deep. Then, the divergence and the convergence of the flow are analyzed in the closed water volume considering the Ekman transport in the surface of this whole region. The accumulated mass transport along the perimeter of the box is estimated with the aim to study transport imbalances in the different water masses. In addition, variables like the anomalies in the transport of the salt and heat are also considered. In general, mass transport results show that more than 50% of this transport takes place in central waters and around 25% in intermediate waters. In the first cruise carried out in late summer, the circulation of the shallowest layers goes into the box along the north and south transects with values which can arrive to 2 Sv and 1 Sv respectively and it flows westward with a maximum value of 2 Sv. At intermediate levels the mass transport changes its direction going out to the north with 0.5 Sv. On the other hand, in the second cruise carried out in late spring, the transport in the shallowest layers also gets in the box through the north transect, but it goes out along the west and south transects with values which can arrive to 1 Sv and 2 Sv, respectively. At intermediate levels the transports are similar to those already described for the summer cruise. Finally, an inverse box model is applied to both datasets to obtain a solution consistent with both the thermal wind equation and with the mass and

Genome sequence, population history, and pelage genetics of the endangered African wild dog (Lycaon pictus).

Science.gov (United States)

Campana, Michael G; Parker, Lillian D; Hawkins, Melissa T R; Young, Hillary S; Helgen, Kristofer M; Szykman Gunther, Micaela; Woodroffe, Rosie; Maldonado, Jesús E; Fleischer, Robert C

2016-12-09

The African wild dog (Lycaon pictus) is an endangered African canid threatened by severe habitat fragmentation, human-wildlife conflict, and infectious disease. A highly specialized carnivore, it is distinguished by its social structure, dental morphology, absence of dewclaws, and colorful pelage. We sequenced the genomes of two individuals from populations representing two distinct ecological histories (Laikipia County, Kenya and KwaZulu-Natal Province, South Africa). We reconstructed population demographic histories for the two individuals and scanned the genomes for evidence of selection. We show that the African wild dog has undergone at least two effective population size reductions in the last 1,000,000 years. We found evidence of Lycaon individual-specific regions of low diversity, suggestive of inbreeding or population-specific selection. Further research is needed to clarify whether these population reductions and low diversity regions are characteristic of the species as a whole. We documented positive selection on the Lycaon mitochondrial genome. Finally, we identified several candidate genes (ASIP, MITF, MLPH, PMEL) that may play a role in the characteristic Lycaon pelage.

Microfouling communities from pelagic and benthic marine plastic debris sampled across Mediterranean coastal waters

Directory of Open Access Journals (Sweden)

Mercedes Masó

2016-09-01

Full Text Available The present study used scanning electron microscopy to characterize the organisms colonizing marine plastic debris collected from pelagic and benthic habitats across Mediterranean coastal waters of Greece, Italy and Spain. A total of 42 fragments of plastic were collected during the COMSOM experimental cruise, 16 from the seafloor and 26 from surface waters. The results showed that diatoms were the most abundant organisms on both pelagic and benthic plastics. The diatom Ceratoneis closterium, frequently observed on surface plastics (73%, is a harmful microalgae associated with mucilage events in the Mediterranean. The abundance of marine plastic in coastal and oceanic waters may provide new habitats that offer an easy substrate for these invasive organisms. Furthermore, the colonization of these new environments might reduce the success of life strategies, or drive the organisms out of their essential habitat by dispersion and rafting phenomena. The results of the present work highlight the need to increase our knowledge of the consequences of colonization of plastics introduced into the marine environment, and the need to raise awareness of the potential impacts of debris accumulation on biodiversity of marine ecosystems.

Changes in patterns of persistent halogenated compounds through a pelagic food web in the Baltic Sea

DEFF Research Database (Denmark)

Stephansen, Diana Agnete; Svendsen, Tore Christian; Vorkamp, Katrin

2012-01-01

The concentrations and patterns of persistent halogenated compounds (PHCs), including polychlorinated biphenyls (PCBs), DDT, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDEs) were examined in a pelagic food web from the southern Baltic Sea consisting...... for the assessment of PHC patterns, e.g. for tracing migratory fish....

Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

KAUST Repository

Kü rten, Benjamin; Al-Aidaroos, Ali M.; Kurten, Saskia; El-Sherbiny, Mohsen M.; Devassy, Reny P.; Struck, Ulrich; Zarokanellos, Nikolaos; Jones, Burton; Hansen, Thomas; Bruss, Gerd; Sommer, Ulrich

2015-01-01

Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one

Higher mass-independent isotope fractionation of methylmercury in the pelagic food web of Lake Baikal (Russia).

Science.gov (United States)

Perrot, Vincent; Pastukhov, Mikhail V; Epov, Vladimir N; Husted, Søren; Donard, Olivier F X; Amouroux, David

2012-06-05

Mercury undergoes several transformations that influence its stable isotope composition during a number of environmental and biological processes. Measurements of Hg isotopic mass-dependent (MDF) and mass-independent fractionation (MIF) in food webs may therefore help to identify major sources and processes leading to significant bioaccumulation of methylmercury (MeHg). In this work, δ(13)C, δ(15)N, concentration of Hg species (MeHg, inorganic Hg), and stable isotopic composition of Hg were determined at different trophic levels of the remote and pristine Lake Baikal ecosystem. Muscle of seals and different fish as well as amphipods, zooplankton, and phytoplankton were specifically investigated. MDF during trophic transfer of MeHg leading to enrichment of heavier isotopes in the predators was clearly established by δ(202)Hg measurements in the pelagic prey-predator system (carnivorous sculpins and top-predator seals). Despite the low concentrations of Hg in the ecosystem, the pelagic food web reveals very high MIF Δ(199)Hg (3.15-6.65‰) in comparison to coastal fish (0.26-1.65‰) and most previous studies in aquatic organisms. Trophic transfer does not influence MIF signature since similar Δ(199)Hg was observed in sculpins (4.59 ± 0.55‰) and seal muscles (4.62 ± 0.60‰). The MIF is suggested to be mainly controlled by specific physical and biogeochemical characteristics of the water column. The higher level of MIF in pelagic fish of Lake Baikal is mainly due to the bioaccumulation of residual MeHg that is efficiently turned over and photodemethylated in deep oligotrophic and stationary (i.e., long residence time) freshwater columns.

Chlorinated hydrocarbons in a pelagic community

International Nuclear Information System (INIS)

Elder, D.; Fowler, S.W.

1976-01-01

For several years data have been accruing on the distribution of chlorinated hydrocarbon pollutants in marine ecosystems. An overall picture of ambient levels in biota, water and sediments is now emerging however, despite the vast amount of data collected to date, questions still arise as to whether certain pollutants such as chlorinated hydrocarbons are indeed magnified through the marine food web. Evidence both for and against trophic concentration of PCB and DDT compounds has been cited. The answer to this question remains unclear due to lack of adequate knowledge on the relative importance of food and water in the uptake of these compounds as well as the fact that conclusions are often confounded by comparing pollutant concentrations in successive links in the food chain sampled at different geographical locations and/or at different points in time. The situation is further complicated by complex prey-predator relationships that exist in many marine communities. In the present study we have tried to eliminate some of these problems by examining PCB and DOT concentrations in species belonging to a relatively well-defined pelagic food chain sampled at one point in space and time

ASSESSING THE STATE OF THE PELAGIC HABITAT: A CASE STUDY OF PLANKTON AND ITS ENVIRONMENT IN THE WESTERN IRISH SEA

Directory of Open Access Journals (Sweden)

Cordula Scherer

2016-11-01

Full Text Available Much work had been undertaken on tracking change in the condition of marine pelagic ecosystems and on identifying regime shifts. However, it is also necessary to relate change to states of good ecosystem health or what the European Marine Strategy Framework Directive (MSFD calls 'Good Environmental Status' (GES. Drawing on existing scientific and legislative principles, including those of OSPAR's 'Strategy to Combat Eutrophication', we propose a framework for assessing the status of what the MSFD calls the 'pelagic habitat' in temperate coastal seas. The framework uses knowledge of local ecohydrodynamic conditions, especially those relating to the stratification and optical environment, to guide expectations of what would be recognised as healthy in terms of ecosystem 'organisation' and 'vigour'. We apply this framework to the seasonally stratified regime of the Western Irish Sea, drawing on published and new work on stratification, nutrient and phytoplankton seasonal cycles, zooplankton, and the implications of plankton community structure and production for higher trophic levels. We conclude that, despite human pressures including nutrient enrichment, and the food-web effects of fisheries, the pelagic ecosystem here is in GES, and hence may be used as a reference for the 'Plankton Index' method of tracking change in state space in seasonally stratified waters.

Intraguild predation between small pelagic fish in the Bay of Biscay: impact on anchovy (Engraulis encrasicolus L.) egg mortality

KAUST Repository

Bachiller, Eneko

2015-05-12

Small pelagic fish can play an important role in various ecosystems linking lower and upper trophic levels. Among the factor behind the observed inter-annual variations in small pelagic fish abundance, intra- and inter-specific trophic interactions could have a strong impact on the recruitment variability (e.g. anchovy). Egg cannibalism observed in anchovies has been postulated to be a mechanism that determines the upper limit of the population density and self-regulates the population abundance of the species. On the other hand, predation by other guild species is commonly considered as a regulation mechanism between competing species. This study provides empirical evidence of anchovy cannibalism and predation of the main small pelagic fish species on anchovy eggs and estimates the effect of intraguild predation on the anchovy egg mortality rate. Results show that, depending on the year (2008–2009), up to 33 % of the total anchovy egg mortality was the result of sardine predation and up to 4 % was the result of egg cannibalism together with predation by Atlantic and Atlantic Chub mackerel and sprat. Results also indicate that in the Bay of Biscay, fluctuations in the survival index of the early life stages of anchovy are likely to be attributable at least in part to egg cannibalism and especially to a high sardine predation on anchovy eggs. © 2015 Springer-Verlag Berlin Heidelberg

78 FR 79388 - Western Pacific Pelagic Fisheries; Catch and Effort Limits for the U.S. Participating Territories

Science.gov (United States)

2013-12-30

... Hawaii longline fisheries: The deep-set fishery that targets bigeye tuna, and the shallow-set fishery... a management framework and process for specifying fishing catch and effort limits and accountability... process for specifying catch or fishing effort limits and accountability measures for pelagic fisheries in...

Modelling benthic oxygen consumption and benthic-pelagic coupling at a shallow station in the southern North Sea

NARCIS (Netherlands)

Provoost, P.; Braeckman, U.; Van Gansbeke, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J.; Vanaverbeke, J.

2013-01-01

A time-series of benthic oxygen consumption, water-column and sediment chlorophyll concentrations, and temperature in the southern North Sea was subjected to inverse modelling in order to study benthic-pelagic coupling in this coastal marine system. The application of a Markov Chain Monte Carlo

Trace metals in pelagic organisms from the Mediterranean Sea

International Nuclear Information System (INIS)

Fowler, S.W.; Oregioni, B.; LaRosa, J.

1976-01-01

As a result of current interest in heavy metal pollution in the marine environment much information is accruing on the present levels of metals in certain marine species. By far the majority of the studies have involved elemental analysis of coastal organisms which are relatively easy to collect. However, due to inherent problems in sampling, far less information exists on element concentration in pelagic organisms, species which are important in terms of total marine biomass, their position in the food web, and their ability to concentrate and transport relatively large amounts of metals in various ways. Microplankton and larger zooplanktonic and nektonic species were sampled over a wide geographical range throughout the Mediterranean as well as along selected transects to assess possible gradients in metal concentrations in plankton communities

Stakeholder participation in the management of North East Atlantic pelagic fish stocks

DEFF Research Database (Denmark)

Coers, Aukje; Raakjær, Jesper; Olesen, Christian

2012-01-01

When the Regional Advisory Councils (RACs) were created during the last reform of the Common Fisheries Policy (CFP) in 2002, it was recognised that in addition to the five geographically orientated stakeholder lead advisory bodies, a separate RAC dedicated exclusively to pelagic fisheries...... floor. For this reason, as well as the fact that they are usually widely distributed, researching and managing this dynamic group of fishes across the borders of many countries requires a unique approach. Fortunately, despite these complexities, policy makers have succeeded to establish a reasonably...

Impacts of hypoxia on the structure and processes in pelagic communities (zooplankton, macro-invertebrates and fish

Directory of Open Access Journals (Sweden)

W. Ekau

2010-05-01

Full Text Available Dissolved oxygen (DO concentration in the water column is an environmental parameter that is crucial for the successful development of many pelagic organisms. Hypoxia tolerance and threshold values are species- and stage-specific and can vary enormously. While some fish species may suffer from oxygen values of less than 3 mL O₂ L⁻¹ through impacted growth, development and behaviour, other organisms such as euphausiids may survive DO levels as low as 0.1 mL O₂ L⁻¹. A change in the average or the range of DO may have significant impacts on the survival of certain species and hence on the species composition in the ecosystem with consequent changes in trophic pathways and productivity.

Evidence for the deleterious effects of oxygen depletion on pelagic species is scarce, particularly in terms of the effect of low oxygen on development, recruitment and patterns of migration and distribution. While planktonic organisms have to cope with variable DOs and exploit adaptive mechanisms, nektonic species may avoid areas of unfavourable DO and develop adapted migration strategies. Planktonic organisms may only be able to escape vertically, above or beneath the Oxygen Minimum Zone (OMZ. In shallow areas only the surface layer can serve as a refuge, but in deep waters many organisms have developed vertical migration strategies to use, pass through and cope with the OMZ.

This paper elucidates the role of DO for different taxa in the pelagic realm and the consequences of low oxygen for foodweb structure and system productivity. We describe processes in two contrasting systems, the semi-enclosed Baltic Sea and the coastal upwelling system of the Benguela Current to demonstrate the consequences of increasing hypoxia on ecosystem functioning and services.

Submarine canyons as coral and sponge habitat on the eastern Bering Sea slope

Directory of Open Access Journals (Sweden)

Robert J. Miller

2015-07-01

Full Text Available Submarine canyons have been shown to positively influence pelagic and benthic biodiversity and ecosystem function. In the eastern Bering Sea, several immense canyons lie under the highly productive “green belt” along the continental slope. Two of these, Pribilof and Zhemchug canyons, are the focus of current conservation interest. We used a maximum entropy modeling approach to evaluate the importance of these two canyons, as well as canyons in general, as habitat for gorgonian (alcyonacean corals, pennatulacean corals, and sponges, in an area comprising most of the eastern Bering Sea slope and outer shelf. These invertebrates create physical structure that is a preferred habitat for many mobile species, including commercially important fish and invertebrates. We show that Pribilof canyon is a hotspot of structure-forming invertebrate habitat, containing over 50% of estimated high-quality gorgonian habitat and 45% of sponge habitat, despite making up only 1.7% of the total study area. The amount of quality habitat for gorgonians and sponges varied in other canyons, but canyons overall contained more high-quality habitat for structure-forming invertebrates compared to other slope areas. Bottom trawling effort was not well correlated with habitat quality for structure-forming invertebrates, and bottom-contact fishing effort in general, including longlining and trawling, was not particularly concentrated in the canyons examined. These results suggest that if conserving gorgonian coral habitat is a management goal, canyons, particularly Pribilof Canyon, may be a prime location to do this without excessive impact on fisheries.

New maps of Lakshmi Planum and eastern Aphrodite, Venus

Science.gov (United States)

Mcgill, G. E.

1984-01-01

Interest on Venus has centered on three regions; (1) Aphrodite Terra, especially east of the main uplant portion, (2) Ishtar Terra, especially Lakshmi Planum and its bounding scarp and massifs, and (3) Beta Regio-Phoebe Regio. The last region is topographically similar to the East African rift system, and has been inferred to have a similar tectonic origin. The Aphrodite region is part of a 21,000 km long tectonic zone that seems best explained as due to extension, and that may represent hot spots clustered along an incipient divergent plate boundary. The most interesting and complex portion of this tectonic zone is that part of eastern Aphrodite between Thetis Regio and Atla Regio. In contrast, the Lakshmi Planum region has many topographic characteristics suggesting that it is a true continent, and thus indicative of convergence and a thick crust. Detailed topographic contour maps of eastern Aphrodite Terra and of Lakshmi Planum are included.

85 million years of pelagic ecosystem evolution: Pacific Ocean deep-sea ichthyolith records reveal fish community dynamics and a long-term decline in sharks

Science.gov (United States)

Sibert, E. C.; Norris, R. D.; Cuevas, J. M.; Graves, L. G.

2015-12-01

The structure and productivity of open ocean consumers has undergone major changes over the past 85 million years. Here, we present the first long-term detailed records of pelagic fish and sharks utilizing the record of ichthyoliths (teeth and dermal scales) from the deep Pacific Ocean. While the North and South Pacific Oceans show similar patterns throughout the 85 million year history, the North Pacific ichthyolith accumulation is significantly higher than the South Pacific, suggesting that the basin has been a more productive region for tens of millions of years. Fish and sharks were not abundant in the Pacific gyres until ~75 million years ago (Ma) suggesting that neither group was quantitatively important in oligotrophic pelagic food webs prior to the latest Cretaceous. Relative to ray-finned fish, sharks were common in the ancient ocean. Most ichthyolith assemblages have >50% shark dermal scales (denticles), but denticle abundance has been declining in both absolute and relative abundance since the Cretaceous-Paleogene (K/Pg) mass extinction. The accumulation rate of ichthyoliths of both sharks and ray-finned fish was highest in the Early Eocene, during the peak of the Cenozoic 'greenhouse' climate where production of shark dermal denticles and fish teeth increased almost five times over Paleocene production rates. Ichthyolith fluxes fell with cooler climates in the later Eocene and Oligocene, but fish production is almost always higher than in the Cretaceous and Paleocene reflecting the expanded ecological roles and importance of pelagic fish in marine ecosystems. Shark denticle production fell to less than half that of the Cretaceous by 20 Ma when it dropped abruptly to near-zero levels. Currently denticles make up sharks appear to be falling as major pelagic consumers over the Late Cretaceous and Cenozoic, and particularly over the past 20 Ma, perhaps reflecting demographic changes in shark and fish communities, or the rise of resource competition from

The role of zooplankton in the pelagic-benthic coupling of the Southern Ocean

Directory of Open Access Journals (Sweden)

Sigrid B. Schnack-Schiel

2005-12-01

Full Text Available Zooplankton contributes in different ways to pelagic-benthic coupling: Their faecal material is a major route of energy flow and the vertical migrations of many species as well as the production of pelagic larvae by benthic organisms represent different paths to link the two subsystems. Antarctic particle fluxes have been shown to be highly variable in size and composition within a given region and even at the same site from year to year. There are also differences throughout the water column, where particle fluxes close to the sea floor beyond the continental shelf break do not normally show seasonal variation within shallow environments. Commonly, at depths shallower than 500 m, the most evident feature is that more than 90% of the annual fluxes occur during a short period of the spring-summer. This event is masked near the seabed at greater depths due to resupension and lateral advection of particles. Faecal material of various origins is one of the main constituents of the biogenic matter flux. It usually reaches its maximum in February once the early phytoplankton bloom has developed. However, the presence of faecal pellets is ubiquitous during the months of the year when there is enough light to support primary production. At this stage more research is needed to elucidate the particular role of distinct taxa—including among others salps, krill, copepods and protozoans—in the transport of organic matter to the benthos, and their contribution to the biogeochemical cycles of carbon, nitrogen, phosphorus and silicon. Aggregation of particles is another important process controlling the development and dynamics of pelagic-benthic coupling due to its influence on the sinking velocity of particles and the enhancement of organic matter utilisation by members of the microbial loop in the upper layers of the water column. Also in shallow waters, aggregation favours the transfer of high-quality organic matter to the benthic realm. At greater

Comparative Glycoproteome Analysis: Dynamics of Protein Glycosylation during Metamorphic Transition from Pelagic to Benthic Life Stages in Three Invertebrates

KAUST Repository

Chandramouli, Kondethimmanahalli; Zhang, Yu; Wong, Yue Him; Qian, Pei Yuan

2012-01-01

The life cycle of most benthic marine invertebrates has two distinct stages: the pelagic larval stage and the sessile juvenile stage. The transition between the larval stage and the juvenile stage is often abrupt and may be triggered by post

Japanese and Taiwanese pelagic longline fleet dynamics and the impacts of climate change in the southern Indian Ocean

Science.gov (United States)

Michael, P. E.; Wilcox, C.; Tuck, G. N.; Hobday, A. J.; Strutton, P. G.

2017-06-01

Climate change is projected to continue shifting the distribution of marine species, leading to changes in local assemblages and different interactions with human activities. With regard to fisheries, understanding the relationship between fishing fleets, target species catch per unit effort (CPUE), and the environment enhances our ability to anticipate fisher response and is an essential step towards proactive management. Here, we explore the potential impact of climate change in the southern Indian Ocean by modelling Japanese and Taiwanese pelagic longline fleet dynamics. We quantify the mean and variability of target species CPUE and the relative value and cost of fishing in different areas. Using linear mixed models, we identify fleet-specific effort allocation strategies most related to observed effort and predict the future distribution of effort and tuna catch under climate change for 2063-2068. The Japanese fleet's strategy targets high-value species and minimizes the variability in CPUE of the primary target species. Conversely, the Taiwanese strategy indicated flexible targeting of a broad range of species, fishing in areas of high and low variability in catch, and minimizing costs. The projected future mean and variability in CPUE across species suggest a slight increase in CPUE in currently high CPUE areas for most species. The corresponding effort projections suggest a slight increase in Japanese effort in the western and eastern study area, and Taiwanese effort increasing east of Madagascar. This approach provides a useful method for managers to explore the impacts of different fishing and fleet management strategies for the future.

Biofilm and Diatom Succession on Polyethylene (PE) and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

Science.gov (United States)

Eich, Andreas; Mildenberger, Tobias; Laforsch, Christian; Weber, Miriam

2015-01-01

The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth) and a pelagic habitat (3 m water depth) to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM) analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation and composition

Biofilm and Diatom Succession on Polyethylene (PE and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

Directory of Open Access Journals (Sweden)

Andreas Eich

Full Text Available The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth and a pelagic habitat (3 m water depth to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation

Modelling the pelagic nitrogen cycle and vertical particle flux in the Norwegian sea

Science.gov (United States)

Haupt, Olaf J.; Wolf, Uli; v. Bodungen, Bodo

1999-02-01

A 1D Eulerian ecosystem model (BIological Ocean Model) for the Norwegian Sea was developed to investigate the dynamics of pelagic ecosystems. The BIOM combines six biochemical compartments and simulates the annual nitrogen cycle with specific focus on production, modification and sedimentation of particles in the water column. The external forcing and physical framework is based on a simulated annual cycle of global radiation and an annual mixed-layer cycle derived from field data. The vertical resolution of the model is given by an exponential grid with 200 depth layers, allowing specific parameterization of various sinking velocities, breakdown of particles and the remineralization processes. The aim of the numerical experiments is the simulation of ecosystem dynamics considering the specific biogeochemical properties of the Norwegian Sea, for example the life cycle of the dominant copepod Calanus finmarchicus. The results of the simulations were validated with field data. Model results are in good agreement with field data for the lower trophic levels of the food web. With increasing complexity of the organisms the differences increase between simulated processes and field data. Results of the numerical simulations suggest that BIOM is well adapted to investigate a physically controlled ecosystem. The simulation of grazing controlled pelagic ecosystems, like the Norwegian Sea, requires adaptations of parameterization to the specific ecosystem features. By using seasonally adaptation of the most sensible processes like utilization of light by phytoplankton and grazing by zooplankton results were greatly improved.

Correlated Effects of Ocean Acidification and Warming on Behavioral and Metabolic Traits of a Large Pelagic Fish

Directory of Open Access Journals (Sweden)

Taryn D. Laubenstein

2018-05-01

Full Text Available Ocean acidification and warming are co-occurring stressors, yet their effects on early life stages of large pelagic fishes are not well known. Here, we determined the effects of elevated CO2 and temperature at levels projected for the end of the century on activity levels, boldness, and metabolic traits (i.e., oxygen uptake rates in larval kingfish (Seriola lalandi, a large pelagic fish with a circumglobal distribution. We also examined correlations between these behavioral and physiological traits measured under different treatments. Kingfish were reared from the egg stage to 25 days post-hatch in a full factorial design of ambient and elevated CO2 (~500 µatm and ~1000 µatm and temperature (21 °C and 25 °C. Activity levels were higher in fish from the elevated temperature treatment compared with fish reared under ambient temperature. However, elevated CO2 did not affect activity, and boldness was not affected by either elevated CO2 or temperature. Both elevated CO2 and temperature resulted in increased resting oxygen uptake rates compared to fish reared under ambient conditions, but neither affected maximum oxygen uptake rates nor aerobic scope. Resting oxygen uptake rates and boldness were negatively correlated under ambient temperature, but positively correlated under elevated temperature. Maximum oxygen uptake rates and boldness were also negatively correlated under ambient temperature. These findings suggest that elevated temperature has a greater impact on behavioral and physiological traits of larval kingfish than elevated CO2. However, elevated CO2 exposure did increase resting oxygen uptake rates and interact with temperature in complex ways. Our results provide novel behavioral and physiological data on the responses of the larval stage of a large pelagic fish to ocean acidification and warming conditions, demonstrate correlations between these traits, and suggest that these correlations could influence the direction and pace of

Distributional changes of American martens and fishers in eastern North America, 1699-2001: Chapter 4

Science.gov (United States)

Krohn, William B.

2012-01-01

Contractions in the geographic distributions of the American marten ( Martes americana) and fi sher ( M. pennanti) in eastern North America south of the St. Lawrence River between Colonial times (ca. 1650–1800) and the fi sher’s recent range expansion (ca. 1930–present) are well documented, but causal factors in these range contractions have only partially been studied. Traditional explanations for range contractions by both species are forest clearing and unregulated trapping; little consideration has been given to alternative explanations. It has been hypothesized that deep snow limits the distribution of fi shers, and that high fi sher populations limit the distribution of martens. I assessed the potential contributions of these factors to observed range contractions for these species by evaluating expected patterns of change in their historical distributions since Colonial times. Using published data on the distribution of martens and fi shers in eastern North America, including early and contemporary fur-harvest records ( n = 60,702), I found that broad-scale changes in their geographic distributions in eastern North America were consistent with 3 of those expectations, and partially so with a 4th. I recognize that retrospective analyses cannot establish the relative importance of land clearing, unregulated trapping, and changing climatic conditions on observed range contractions; nevertheless, when historical data from eastern North America are viewed in the context of long-term climate warming and the results of recent ecological studies, they suggest that traditional arguments may only partially explain historical range contractions for both species. This study further suggests that under a warming climate, northern range boundaries for the fi sher will expand, and southern range boundaries for the American marten will continue to contract.

Observed and modeled pathways of the Iceland Scotland Overflow Water in the eastern North Atlantic

Science.gov (United States)

Zou, Sijia; Lozier, Susan; Zenk, Walter; Bower, Amy; Johns, William

2017-12-01

The spreading of Iceland Scotland Overflow Water (ISOW) in the eastern North Atlantic has largely been studied in an Eulerian frame using numerical models or with observations limited to a few locations. No study to date has provided a comprehensive description of the ISOW spreading pathways from both Eulerian and Lagrangian perspectives. In this paper, we use a combination of previously unreported current meter data, hydrographic data, RAFOS float data, and a high resolution (1/12°) numerical ocean model to study the spreading pathways of ISOW from both of these perspectives. We identify three ISOW transport cores in the central Iceland Basin (∼59°N), with the major core along the eastern boundary of the Reykjanes Ridge (RR) and the other two in the basin interior. Based on trajectories of observed and/or numerical floats seeded along 59°N, we also describe the ISOW spreading pathways and quantify their relative importance. Within 10 years, 7-11% of ISOW from 59°N escapes into the Irminger Sea via gaps in the RR north of the Charlie Gibbs Fracture Zone (CGFZ); the water that moves through these gaps principally originates from the shallower ISOW layer along the RR eastern boundary. 10-13% travels further southward until the CGFZ, where it crosses westward into the western subpolar gyre. 18-21% of ISOW spreads southward along the eastern flank of the Mid-Atlantic Ridge into the Western European Basin (WEB). Most of the remaining water stays in the Iceland Basin over the 10-year period. A model-based investigation provides a first look at the temporal variability of these ISOW pathways. We find that the fraction of southward water exported into the WEB is anti-correlated with the export through the CGFZ, a result assumed to reflect these pathways' interactions with the North Atlantic Current in magnitude and/or position shift.

Pelagic origin and fate of sedimenting particles in the Norwegian Sea

Science.gov (United States)

Bathmann, Ulrich V.; Peinert, Rolf; Noji, Thomas T.; Bodungen, Bodo V.

A 17 month record of vertical particle flux of dry weight, carbonate and organic carbon were 25.8, 9.4 and 2.4g.m -2y -1, respectively. Parallel to trap deployments, pelagic system structure was recorded with high vertical and temporal resolution. Within a distinct seasonal cycle of vertical particle flux, zooplankton faecal pellets of various sizes, shapes and contents were collected by the traps in different proportions and quantities throughout the year (range: 0-4,500 10 3m -2d -1). The remains of different groups of organisms showed distinct seasonal variations in abundance. In early summer there was a small maximum in the diatom flux and this was followed by pulses of tinntinids, radiolarians, foraminiferans and pteropods between July and November. Food web interactions in the water column were important in controlling the quality and quantity of sinking materials. For example, changes in the population structure of dominant herbivores, the break-down of regenerating summer populations of microflagellates and protozooplankton and the collapse of a pteropod dominated community, each resulted in marked sedimentation pulses. These data from the Norwegian Sea indicate those mechanisms which either accelerate or counteract loss of material via sedimentation. These involve variations in the structure of the pelagic system and they operatè on long (e.g. annual plankton succession) and short (e.g. the end of new production, sporadic grazing of swarm feeders) time scales. Connecting investigation of the water column with a high resolution in time in parallel with drifting sediment trap deployments and shipboard experiments with the dominant zooplankters is a promising approach for giving a better understanding of both the origin and the fate of material sinking to the sea floor.

Attribution of Extreme Rainfall from Landfalling Tropical Cyclones to Climate Change for the Eastern United States

Science.gov (United States)

Liu, M.; Yang, L.; Smith, J. A.; Vecchi, G. A.

2017-12-01

Extreme rainfall and flooding associated with landfalling tropical cyclones (TC) is responsible for vast socioeconomic losses and fatalities. Landfalling tropical cyclones are an important element of extreme rainfall and flood peak distributions in the eastern United States. Record floods for USGS stream gauging stations over the eastern US are closely tied to landfalling hurricanes. A small number of storms account for the largest record floods, most notably Hurricanes Diane (1955) and Agnes (1972). The question we address is: if the synoptic conditions accompanying those hurricanes were to be repeated in the future, how would the thermodynamic and dynamic storm properties and associated extreme rainfall differ in response to climate change? We examine three hurricanes: Diane (1955), Agnes (1972) and Irene (2011), due to the contrasts in structure/evolution properties and their important roles in dictating the upper tail properties of extreme rainfall and flood frequency over eastern US. Extreme rainfall from Diane is more localized as the storm maintains tropical characteristics, while synoptic-scale vertical motion associated with extratropical transition is a central feature for extreme rainfall induced by Agnes. Our analyses are based on ensemble simulations using the Weather Research and Forecasting (WRF) model, considering combinations of different physics options (i.e., microphysics, boundary layer schemes). The initial and boundary conditions of WRF simulations for the present-day climate are using the Twentieth Century Reanalysis (20thCR). A sub-selection of GCMs is used, as part of phase 5 of the Coupled Model Intercomparison Project (CMIP5), to provide future climate projections. For future simulations, changes in model fields (i.e., temperature, humidity, geopotential height) between present-day and future climate are first derived and then added to the same 20thCR initial and boundary data used for the present-day simulations, and the ensemble is

Pollutants and parasites in bycatch teleosts from south eastern Spanish Mediterranean's fisheries: Concerns relating the foodstuff harnessing

International Nuclear Information System (INIS)

Casadevall, Margarida; Torres, Jordi; El Aoussimi, Ahmed; Carbonell, Ana; Delgado, Eulàlia; Sarrà-Alarcón, Lídia; García-Ruíz, Cristina

2016-01-01

This research provides an evaluation of the quality and health status of some locally abundant fish species, usually otter-trawl bycatch species. The study was conducted in the southern and eastern Spanish Mediterranean coast. Mean concentration of heavy metals in muscle and parasitisation indices showed moderate levels. Higher lead concentration was found in fish from the western Alboran and arsenic, cadmium and mercury were more present on fishes from the eastern Alboran area, although most species analysed contain moderate levels of heavy metals in muscle. Concerning parasitisation, F. Anisakidae nematodes were present in all the species, except sardine. Only mercury showed a positive relationship with parasitisation. We also considered three feeding guilds. Metal mean concentrations were higher in benthivores and more littoral fishes. Pelagic planktivores species are the healthiest and the more suitable for consumers from the sanitary point of view. -- Highlights: •Planktophagous fishes always presented significant lower concentrations of heavy metals in muscle. •Benthivorous and fishes with mixed diets showed higher concentrations of heavy metals in muscle. •Fishes from the western Alboran and Vera Gulf areas presented higher levels of Pb. •Specimens infected (mainly by nematodes) had more concentration of mercury in muscle. •Overall, species and areas analysed in this work show moderate levels of parasite infection and heavy metals accumulation in muscle.

Evidence for foraging -site fidelity and individual foraging behavior of pelagic cormorants rearing chicks in the gulf of Alaska

Science.gov (United States)

Kotzerka, J.; Hatch, Shyla A.; Garthe, S.

2011-01-01

The Pelagic Cormorant (Phalacrocorax pelagicus) is the most widespread cormorant in the North Pacific, but little is known about its foraging and diving behavior. However, knowledge of seabirds' foraging behavior is important to understanding their function in the marine environment. In 2006, using GPS dataloggers, we studied the foraging behavior of 14 male Pelagic Cormorants rearing chicks on Middleton Island, Alaska. For foraging, the birds had high fidelity to a small area 8 km north of the colony. Within that area, the cormorants' diving activity was of two distinct kinds-near-surface dives (1-6 m) and benthic dives (28-33 m). Individuals were consistent in the depths of their dives, either mostly shallow or mostly deep. Few showed no depth preference. Dive duration, time at maximum depth, and pauses at the water surface between consecutive dives were shorter for shallow dives than for deep dives. The cormorants made dives of both types throughout the day, but the frequency of deep dives increased toward evening. Maximum foraging range was 9 km; maximum total distance traveled per trip was 43.4 km. Trip durations ranged from 0.3 to 7.7 hr. Maximum depth of a dive was 42.2 m, and duration of dives ranged from 4 to 120 sec. We found that Pelagic Cormorants at Middleton Island were faithful to one particular foraging area and individuals dived in distinct patterns. Distinct, specialized foraging behavior may be advantageous in reducing intra- and interspecific competition but may also render the species vulnerable to changing environmental conditions. Copyright ?? The Cooper Ornithological Society 2011.

Pelagic larval duration predicts extinction risk in a freshwater fish clade.

Science.gov (United States)

Douglas, Morgan; Keck, Benjamin P; Ruble, Crystal; Petty, Melissa; Shute, J R; Rakes, Patrick; Hulsey, C Darrin

2013-01-01

Pelagic larval duration (PLD) can influence evolutionary processes ranging from dispersal to extinction in aquatic organisms. Using estimates of PLD obtained from species of North American darters (Percidae: Etheostomatinae), we demonstrate that this freshwater fish clade exhibits surprising variation in PLD. Comparative analyses provide some evidence that higher stream gradients favour the evolution of shorter PLD. Additionally, similar to patterns in the marine fossil record in which lower PLD is associated with greater extinction probability, we found a reduced PLD in darter lineages was evolutionarily associated with extinction risk. Understanding the causes and consequences of PLD length could lead to better management and conservation of organisms in our increasingly imperiled aquatic environments.

Middle Eastern rhinoplasty.

Science.gov (United States)

Azizzadeh, Babak; Mashkevich, Grigoriy

2010-02-01

The ethnic appearance of the Middle Eastern nose is defined by several unique visual features, particularly a high radix, wide overprojecting dorsum, and an amorphous hanging nasal tip. These external characteristics reflect distinct structural properties of the osseo-cartilaginous nasal framework and skin-soft tissue envelope in patients of Middle Eastern extraction. The goal, and the ultimate challenge, of rhinoplasty on Middle Eastern patients is to achieve balanced aesthetic refinement, while avoiding surgical westernization. Detailed understanding of the ethnic visual harmony in a Middle Eastern nose greatly assists in preserving native nasal-facial relationships during rhinoplasty on Middle Eastern patients. Esthetic alteration of a Middle Eastern nose follows a different set of goals and principles compared with rhinoplasties on white or other ethnic patients. This article highlights the inherent nasal features of the Middle Eastern nose and reviews pertinent concepts of rhinoplasty on Middle Eastern patients. Essential considerations in the process spanning the consultation and surgery are reviewed. Reliable operative techniques that achieve a successful aesthetic outcome are discussed in detail. Copyright 2010 Elsevier Inc. All rights reserved.

Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks in the central Pacific Ocean

DEFF Research Database (Denmark)

Musyl, Michael K.; Brill, Richard W.; Curran, Daniel S.

2011-01-01

]) in the central Pacific Ocean to determine speciesspecific movement patterns and survival rates after release from longline fishing gear. Only a single postrelease mortality could be unequivocally documented: a male blue shark which succumbed seven days after release. Meta-analysis of published reports......From 2001 to 2006, 71 pop-up satellite archival tags (PSATs) were deployed on five species of pelagic shark (blue shark [Prionace glauca]; shortfin mako [Isurus oxyrinchus]; silky shark [Carcharhinus falciformis]; oceanic whitetip shark [C. longimanus]; and bigeye thresher [Alopias superciliosus...... and the current study (n=78 reporting PSATs) indicated that the summary effect of postrelease mortality for blue sharks was 15% (95% CI, 8.5-25.1%) and suggested that catch-and-release in longline fisheries can be a viable management tool to protect parental biomass in shark populations. Pelagic sharks displayed...

STUDY ON OCEANGRAFHIC AND WEATHER CONDITIONS RELATED TO THE ABUNDANCE OF SMALL PELAGIC FISHERY IN NATUNA SEA USING REMOTE SENSING DATA

Directory of Open Access Journals (Sweden)

Teguh Prayogo

2012-11-01

Full Text Available Indonesian waters have abundance of natural resources; the potential of small pelagic fish in Natuna Sea and SouthChina Sea have not been optimized yet explores. Unfortunately, it was caused by lacking in the data of environmentalconditions that have been changed and the information of appropriate fishing ground. Hence, dynamical oceanographicinformation and weather condition is necessary to optimize small pelagic fish exploitation.Research location in Natuna Sea and its surrounding with geographical position is 08°N–03°S; 103°–111°E. Theoceanographic condition representative by monthly SST, Chl-a, SSH that derived from satellite data and Dipole ModeIndex for 2002-2007 from FRCGC website. Monthly wind data is variable for weather condition. Small pelagic fishabundance representative by annual fish production (2002-2005 and monthly Catch Per Unit Effort (CPUE ofGoldstripe sardinella, Bigeye scad and Indian scad (2006. It was data collected from Directorate General of CaptureFisheries (Ministry of Marine Affairs and Fisheries and daily fishing operation (2007 used to calculate match-up ratiothat was collected from Pemangkat fishing port in West Kalimantan. Research process consists of image processing,descriptive correlation analysis and GIS analysis to predict fishing ground map and match-up ratio calculation.Result of this research is the annual fish catch production of Bigeye scad and Indian scad (2002-2005 is tend toincrease and the monthly CPUE of both species is high during SE Monsoon (May-Sep that is condition contrarily in NWMonsoon (Nov-Apr. Meanwhile, the annual fish catch production of Goldstripe sardinella production is tend to decreasefrom 2002-2005, it has CPUE is high in early SE Monsoon (May. During the SE Monsoon (May-Sep when DM Index ispositive (+ the Indian scad and Bigeye scad production is high, for Goldstripe sardinella the fish production is highwhen DM Index is positive (+ in May. The accuracy of prediction map of

Climate change impacts on coastal and pelagic environments in the southeastern Bay of Biscay

OpenAIRE

Chust, G; Borja, Á; Caballero, A; Irigoien, X; Sáenz, J; Moncho, R; Marcos, M; Liria, P; Hidalgo, J; Valle, M; Valencia, V

2011-01-01

International audience; The impacts of global climate change on the Basque coast and the pelagic systems within the southeastern Bay of Biscay are reviewed. Climate projections under greenhouse gas emission scenarios indicate that this area will experience changes in climate throughout the 21st century, including warming of surface air (especially heat wave episodes), intensification of extreme daily rainfall (10%), warming of the upper 100 m of the ocean layer (1.5 to 2.05°C), and sea level ...

Persistent organic pollutants in fat of three species of Pacific pelagic longline caught sea turtles: Accumulation in relation to ingested plastic marine debris

Science.gov (United States)

Clukey, Katharine; Lepczyk, Christopher A.; Balazs, George H.; Work, Thierry M.; Li, Qing X.; Bachman, Melanie J.; Lynch, Jennifer M.

2017-01-01

In addition to eating contaminated prey, sea turtles may be exposed to persistent organic pollutants (POPs) from ingesting plastic debris that has absorbed these chemicals. Given the limited knowledge about POPs in pelagic sea turtles and how plastic ingestion influences POP exposure, our objectives were to: 1) provide baseline contaminant levels of three species of pelagic Pacific sea turtles; and 2) assess trends of contaminant levels in relation to species, sex, length, body condition and capture location. In addition, we hypothesized that if ingesting plastic is a significant source of POP exposure, then the amount of ingested plastic may be correlated to POP concentrations accumulated in fat. To address our objectives we compared POP concentrations in fat samples to previously described amounts of ingested plastic from the same turtles. Fat samples from 25 Pacific pelagic sea turtles [2 loggerhead (Caretta caretta), 6 green (Chelonia mydas) and 17 olive ridley (Lepidochelys olivacea) turtles] were analyzed for 81 polychlorinated biphenyls (PCBs), 20 organochlorine pesticides, and 35 brominated flame-retardants. The olive ridley and loggerhead turtles had higher ΣDDTs (dichlorodiphenyltrichloroethane and metabolites) than ΣPCBs, at a ratio similar to biota measured in the South China Sea and southern California. Green turtles had a ratio close to 1:1. These pelagic turtles had lower POP levels than previously reported in nearshore turtles. POP concentrations were unrelated to the amounts of ingested plastic in olive ridleys, suggesting that their exposure to POPs is mainly through prey. In green turtles, concentrations of ΣPCBs were positively correlated with the number of plastic pieces ingested, but these findings were confounded by covariance with body condition index (BCI). Green turtles with a higher BCI had eaten more plastic and also had higher POPs. Taken together, our findings suggest that sea turtles accumulate most POPs through their prey rather

Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

Science.gov (United States)

Poag, C.W.

2005-01-01

This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. 

Benthic-pelagic coupling: effects on nematode communities along southern European continental margins.

Directory of Open Access Journals (Sweden)

Ellen Pape

Full Text Available Along a west-to-east axis spanning the Galicia Bank region (Iberian margin and the Mediterranean basin, a reduction in surface primary productivity and in seafloor flux of particulate organic carbon was mirrored in the in situ organic matter quantity and quality within the underlying deep-sea sediments at different water depths (1200, 1900 and 3000 m. Nematode standing stock (abundance and biomass and genus and trophic composition were investigated to evaluate downward benthic-pelagic coupling. The longitudinal decline in seafloor particulate organic carbon flux was reflected by a reduction in benthic phytopigment concentrations and nematode standing stock. An exception was the station sampled at the Galicia Bank seamount, where despite the maximal particulate organic carbon flux estimate, we observed reduced pigment levels and nematode standing stock. The strong hydrodynamic forcing at this station was believed to be the main cause of the local decoupling between pelagic and benthic processes. Besides a longitudinal cline in nematode standing stock, we noticed a west-to-east gradient in nematode genus and feeding type composition (owing to an increasing importance of predatory/scavenging nematodes with longitude governed by potential proxies for food availability (percentage of nitrogen, organic carbon, and total organic matter. Within-station variability in generic composition was elevated in sediments with lower phytopigment concentrations. Standing stock appeared to be regulated by sedimentation rates and benthic environmental variables, whereas genus composition covaried only with benthic environmental variables. The coupling between deep-sea nematode assemblages and surface water processes evidenced in the present study suggests that it is likely that climate change will affect the composition and function of deep-sea nematodes.

The interplay between subduction and lateral extrusion: A case study for the European Eastern Alps based on analogue models

Science.gov (United States)

van Gelder, I. E.; Willingshofer, E.; Sokoutis, D.; Cloetingh, S. A. P. L.

2017-08-01

A series of analogue experiments simulating intra-continental subduction contemporaneous with lateral extrusion of the upper plate are performed to study the interference between these two processes at crustal levels and in the lithospheric mantle. The models demonstrate that intra-continental subduction and coeval lateral extrusion of the upper plate are compatible processes leading to similar deformation structures within the extruding region as compared to the classical setup, lithosphere-scale indentation. Strong coupling across the subduction boundary allows for the transfer of stresses to the upper plate, where strain regimes are characterized by crustal thickening near a confined margin and dominated by lateral displacement of material near a weak lateral confinement. The strain regimes propagate laterally during ongoing convergence creating an area of overlap characterized by transpression. When subduction is oblique to the convergence direction, the upper plate is less deformed and as a consequence the amount of lateral extrusion decreases. In addition, strain is partitioned along the oblique plate boundary resulting in less subduction in expense of right lateral displacement close to the weak lateral confinement. Both oblique and orthogonal subduction models have a strong resemblance to lateral extrusion tectonics of the Eastern Alps (Europe), where subduction of the adjacent Adriatic plate beneath the Eastern Alps is debated. Our results imply that subduction of Adria is a valid mechanisms to induce extrusion-type deformation within the Eastern Alps lithosphere. Furthermore, our findings suggest that the Oligocene to Late Miocene structural evolution of the Eastern Alps reflects a phase of oblique subduction followed by a later stage of orthogonal subduction conform a Miocene shift in the plate motion of Adria. Oblique subduction also provides a viable mechanism to explain the rapid decrease in slab length of the Adriatic plate beneath the Eastern Alps

Status and trends of the major roundfish, flatfish, and pelagic fish stocks in the North Sea: thirty- year overview

NARCIS (Netherlands)

Serchuk, F.M.; Kirkegaard, E.; Daan, N.

1996-01-01

Changes in the status of the major roundfish, flatfish, and pelagic stocks in the North Sea over the past 30 years are reviewed. Synopses are presented on trends in catches, fishing mortality, spawning-stock biomass, and recruitment for eight stocks (cod, haddock, whitting, saithe, plaice, sole,

Metal accumulation rates in northwest Atlantic pelagic sediments

International Nuclear Information System (INIS)

Thomson, J.; Carpenter, M.S.N.; Colley, S.; Wilson, T.R.S.; Elderfield, H.; Kennedy, H.

1984-01-01

Measurements of 230 Th, 87 Sr/ 86 Sr and twenty-four metals were made on cores from the Nares Abyssal Plain. The sediment is characterized by slowly-accumulating pelagic red clays and rapidly deposited grey clays transported by turbidity currents. Despite their colour differences and the enrichment of certain elements in the red clays, Sr isotope evidence demonstrates that the clays have the same terrigenous origin. The excesses of metals in the red clays have been attributed to metal removal from the water column and a comparison with the grey clays has enabled the authigenic fluxes of metals to be estimated. The results are given for the elements Mn, Fe, Cu, Co, Ni, Zn, V, Sr, Ce, La, Nd, Sm, Eu, Gd, Dy, Er and Yb. Authigenic fluxes of Y, Nb, Cr, Zr, Rb, U and Th were not resolvable. Fluxes appear to be near constant on the Plain but comparison with other areas shows that they are quite variable both between and within ocean basins. The chief factor controlling authigenic fluxes is discussed. (author)

Dinitrogen Fixation Within and Adjacent to Oxygen Deficient Waters of the Eastern Tropical South Pacific Ocean

Science.gov (United States)

Widner, B.; Mulholland, M. R.; Bernhardt, P. W.; Chang, B. X.; Jayakumar, A.

2016-02-01

Recent work suggests that planktonic diazotrophs are geographically more widely distributed than previously thought including relatively warm (14-23oC) aphotic oxygenated pelagic waters and in aphotic waters within oxygen deficient zones. Because the volume of aphotic water in the ocean is large and may increase in the future, if dinitrogen (N2) fixation is widely occurring at sub-euphotic depths, this could result in a dramatic upward revision of global nitrogen (N) inputs via this process. N2 fixation rates were measured during a cruise in the Eastern Tropical South Pacific using stable isotope tracer techniques that account for slow gas dissolution. Results are compared with light, nutrient, and oxygen gradients (and necessarily temperature gradients). In addition, rates of N2 fixation made in vertical profiles within and above oxygen deficient waters are compared with those measured in vertical profiles adjacent to oxygen deficient waters. Results suggest that while rates of N2 fixation were measurable in deeper anoxic waters, volumetric N2 fixation rates were higher in surface waters.

Pelagic shark fisheries of Indonesia's Eastern Indian Ocean ...

African Journals Online (AJOL)

Sharks are commonly caught in Indonesian waters both by target fisheries and as bycatch. Fishers targeting sharks mostly employ drift longlines, whereas tuna longlines and gillnets are the gear mostly responsible for shark bycatch. Our studies on shark fisheries have been conducted since 2006 and have focused on the ...

Rivers as Political Boundaries: Peru and its Dynamic Borders

Science.gov (United States)

Abad, J. D.; Escobar, C.; Garcia, A. M. P.; Ortals, C.; Frias, C. E.; Vizcarra, J.

2014-12-01

Rivers, although inherently dynamic, have been chosen as political boundaries since the beginning of colonization for several reasons. Such divisions were chosen namely for their defensive capabilities and military benefits, and because they were often the first features mapped out by explorers. Furthermore, rivers were indisputable boundaries that did not require boundary pillars or people to guard them. However, it is important to understand the complexities of a river as a boundary. All rivers inevitably change over time through processes such as accretion, deposition, cut-off, or avulsion, rendering a political boundary subject to dispute. Depending upon the flow, size, and surrounding land, a river will migrate differently than others. As these natural features migrate one country loses land while another gains land leading to tension between legal rigidity and fluid dynamism. This in turn can manifest in social disruption due to cultural differences, political upheaval, or conflict risk as a result of scarce water resources. The purpose of this research is to assess the temporal and spatial variability of the political boundaries of Peru that follow rivers. Peru shares borders with Colombia, Brazil, Bolivia, Chile, and Ecuador. A large part of its northern border with Colombia follows the Putumayo River and later the Amazon River. Part of its eastern border with Brazil follows the Yavari River and later the Yaquirana River. These rivers are natural features used as political boundaries yet they differ in how each migrates. By means of a spatial and temporal analysis of satellite images it was possible to obtain erosion and deposition areas for the Putumayo River, the portion of the Amazon River that is part of the Peruvian boundary, the Yavari River, and the Yaquirana River. The erosion and deposition areas were related to land distribution among Peru, Colombia, and Brazil. By examining the Digital Elevation Model one can see how the altitude of the

Geophysical constraints for terrane boundaries in southern Mongolia

Science.gov (United States)

Guy, Alexandra; Schulmann, Karel; Munschy, Marc; Miehe, Jean-Marc; Edel, Jean-Bernard; Lexa, Ondrej; Fairhead, Derek

2014-05-01

associated to upright folding. The magnetic signal is interpreted to result from a giant Permo-Triassic magmatic event associated lithosphere scale deformation whereas the gravity pattern is related to post-accretionary shortening of the CAOB in between North China and Siberia cratons. The blurring of the gravity signals to the west is attributed to activity of Triassic dextral shear zones parallel to the eastern Siberian boundary later on affected by Cretaceous extension and magmatism affecting the whole of eastern Asia.

Aspects of middle cretaceous pelagic sedimentation in Southern Europe : production and storage of organic matter, stable isotopes, and astronomical influences

NARCIS (Netherlands)

Boer, P.L. de

1983-01-01

Large amounts of organic carbon were stored as black shales in pelagic sediments during the Lower and Middle Cretaceous, especially within the Tethyan and North Atlantic oceans and their marginal basins (Schlanger & Jenkyns, 1976; Fischer &Arthur, 1977; Ryan & Cita, 1977; Thiede & van

Glacial-Holocene variability in pelagic denitrification and OMZ intensity along the NW Mexican Margin

Science.gov (United States)

Ontiveros Cuadras, J. F.; Thunell, R.; Ruiz-Fernandez, A. C.; Machain-Castillo, M. L.; Tappa, E.

2017-12-01

Denitrification of fixed nitrogen represents a substantial loss of bioavailable nitrogen from the ocean, thus playing a major role in the global nitrogen cycle. Water-column (pelagic) denitrification occurs mostly in the oxygen minimum zones (OMZs), which are situated beneath coastal upwelling areas that are characterized by high settling fluxes of organic detritus and high rates of oxygen utilization from remineralization. Our study uses biogenic components (total organic carbon and opal) and δ15N values of sediments from the NW Mexican Margin to reconstruct variations in denitrification and strength of the OMZ in the eastern tropical North Pacific (ETNP) for the last 36,000 years. During the last glacial period (LGM, 23-18 kyr) the associations between relatively low δ15N values (7-8‰) and low TOC (2-4%) and opal (1-4%) content indicates reduced denitrification due to reduced upwelling and decreased flux of organic matter through the OMZ. This was followed by abrupt acceleration of water-column denitrification (δ15N, 7-10‰) and the strengthening of the OMZ during the latter half of Heinrich Stadial 1 (HS1; 18-14.7 kyr). However, the biogenic component of sediments deposited during HS1 do not increase appreciably, suggesting that the increase in denitrification was not driven by an increase in productivity. Furthermore, the increase in δ15N precedes the deglacial decrease in planktonic foraminiferal δ18O which mostly occurs during the Bolling Alerod (14.7-12.9 kyr). This suggests that the increase in denitrification was not a response to surface warming. Rather, we attribute the rapid increase in denitrification during HS1 to reduced ventilation of the ETNP OMZ. Following the peak in denitrification at the end of HS1, we observe a small but steady decline in δ15N over the last 15 kyr. Higher TOC in Holocene sediments relative to glacial sediments suggests that increased productivity has played a role in maintaining a strong OMZ throughout the Holocene.

Meso- and bathy-pelagic fish parasites at the Mid-Atlantic Ridge (MAR): Low host specificity and restricted parasite diversity

Science.gov (United States)

Klimpel, Sven; Busch, Markus Wilhelm; Sutton, Tracey; Palm, Harry Wilhelm

2010-04-01

Seven meso- and bathy-pelagic fish species from the Mid-Atlantic Ridge (MAR) were firstly studied for fish parasites and feeding ecology. With a total of seven parasite species, the 247 meso- and bathy-pelagic deep-sea fish specimens belonging to the families Melamphaidae (3 spp.), Myctophidae (3 spp.) and Stomiidae (1 sp.) revealed low parasite diversity. The genetically identified nematodes Anisakis simplex (s.s.) and Anisakis pegreffii from the body cavity, liver and muscles of Myctophum punctatum were the most abundant parasites, reaching a prevalence of 91.4% and mean intensity of 3.1 (1-14). Anisakis sp. (unidentified) infected Chauliodus sloani and Poromitra crassiceps. Bothriocephalidean and tetraphyllidean cestode larvae infected Benthosema glaciale, the latter also occurring in C. sloani and Scopelogadus beanii, at low prevalences. Adult parasites at low infection rates included the digenean Lethadena sp. (2.9%), and the two copepod species Sarcotretes scopeli (5.7%) and Tautochondria dolichoura (5.3-11.4%). The myctophid Lampanyctus macdonaldi and the melamphaid Scopelogadus mizolepis mizolepis were free of parasites. Analyses of the stomach contents revealed crustaceans, especially copepods and euphausiids for the myctophids and also amphipods for the melamphaids as predominant prey items. While all stomachs showing distinct content comprising often unidentified 'tissue' (possibly gelatinous zooplankton), only C. sloani preyed upon fish. Though this feeding habit would enable transfer of a variety of crustacean-transmitted parasites into the fish, the parasite fauna in the meso- and bathy-pelagic fish was species poor. All observed parasites showed low host specificity, demonstrating no distinct pattern of host-parasite co-evolution. The MAR is no barrier for the parasite distribution in the North Atlantic meso- and bathy-pelagial.

Climate variability and change scenarios for a marine commodity: Modelling small pelagic fish, fisheries and fishmeal in a globalized market

Science.gov (United States)

Merino, Gorka; Barange, Manuel; Mullon, Christian

2010-04-01

The world's small pelagic fish populations, their fisheries, fishmeal and fish oil production industries and markets are part of a globalised production and consumption system. The potential for climate variability and change to alter the balance in this system is explored by means of bioeconomic models at two different temporal scales, with the objective of investigating the interactive nature of environmental and human-induced changes on this globalised system. Short-term (interannual) environmental impacts on fishmeal production are considered by including an annual variable production rate on individual small pelagic fish stocks over a 10-year simulation period. These impacts on the resources are perceived by the fishmeal markets, where they are confronted by two aquaculture expansion hypotheses. Long-term (2080) environmental impacts on the same stocks are estimated using long-term primary production predictions as proxies for the species' carrying capacities, rather than using variable production rates, and are confronted on the market side by two alternative fishmeal management scenarios consistent with IPCC-type storylines. The two scenarios, World Markets and Global Commons, are parameterized through classic equilibrium solutions for a global surplus production bioeconomic model, namely maximum sustainable yield and open access, respectively. The fisheries explicitly modelled in this paper represent 70% of total fishmeal production, thus encapsulating the expected dynamics of the global production and consumption system. Both short and long-term simulations suggest that the sustainability of the small pelagic resources, in the face of climate variability and change, depends more on how society responds to climate impacts than on the magnitude of climate alterations per se.

57Fe Mössbauer analysis of the Upper Triassic-Lower Jurassic deep-sea chert: Paleo-redox history across the Triassic-Jurassic boundary and the Toarcian oceanic anoxic event

International Nuclear Information System (INIS)

Sato, Tomohiko; Isozaki, Yukio; Shozugawa, Katsumi; Seimiya, Kimiko; Matsuo, Motoyuki

2012-01-01

We investigated the paleo-redox change across the Triassic-Jurassic (T-J) boundary (∼200 Ma) and the Early Toarcian oceanic anoxic event (T-OAE; ∼183 Ma) recorded in the Upper Triassic to Lower Jurassic pelagic deep-sea cherts in the Inuyama area, Central Japan. The present 57 Fe Mössbauer spectroscopic analysis for these cherts identified five iron species, i.e., hematite (α-Fe 2 O 3 ), pyrite (FeS 2 ), paramagnetic Fe 3 +  , and two paramagnetic Fe 2 +  with different quadrupole splittings. The occurrence of hematite and pyrite in deep-sea cherts essentially indicates primary oxidizing and reducing depositional conditions, respectively. The results confirmed that oxidizing conditions persisted in deep-sea across the T-J boundary. In contrast, across the T-OAE, deep-sea environment shifted to reducing conditions. The first appearance of the gray pyrite-bearing chert marked the onset of the deep-sea oxygen-depletion in the middle Pliensbachian, i.e., clearly before the shallow-sea T-OAE.

Ocean-wide tracking of pelagic sharks reveals extent of overlap with longline fishing hotspots.

Science.gov (United States)

Queiroz, Nuno; Humphries, Nicolas E; Mucientes, Gonzalo; Hammerschlag, Neil; Lima, Fernando P; Scales, Kylie L; Miller, Peter I; Sousa, Lara L; Seabra, Rui; Sims, David W

2016-02-09

Overfishing is arguably the greatest ecological threat facing the oceans, yet catches of many highly migratory fishes including oceanic sharks remain largely unregulated with poor monitoring and data reporting. Oceanic shark conservation is hampered by basic knowledge gaps about where sharks aggregate across population ranges and precisely where they overlap with fishers. Using satellite tracking data from six shark species across the North Atlantic, we show that pelagic sharks occupy predictable habitat hotspots of high space use. Movement modeling showed sharks preferred habitats characterized by strong sea surface-temperature gradients (fronts) over other available habitats. However, simultaneous Global Positioning System (GPS) tracking of the entire Spanish and Portuguese longline-vessel fishing fleets show an 80% overlap of fished areas with hotspots, potentially increasing shark susceptibility to fishing exploitation. Regions of high overlap between oceanic tagged sharks and longliners included the North Atlantic Current/Labrador Current convergence zone and the Mid-Atlantic Ridge southwest of the Azores. In these main regions, and subareas within them, shark/vessel co-occurrence was spatially and temporally persistent between years, highlighting how broadly the fishing exploitation efficiently "tracks" oceanic sharks within their space-use hotspots year-round. Given this intense focus of longliners on shark hotspots, our study argues the need for international catch limits for pelagic sharks and identifies a future role of combining fine-scale fish and vessel telemetry to inform the ocean-scale management of fisheries.

Guidelines for earthquake ground motion definition for the Eastern United States

International Nuclear Information System (INIS)

Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

1985-01-01

Guidelines for the determination of earthquake ground-motion definition for the eastern United States are established in this paper. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large to great (M > 7.5) sized earthquakes have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes have been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data has been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the Safe Shutdown Earthquake, SSE. A new procedure for establishing the Operating Basis Earthquake, OBE, is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors

Stranding survey as a framework to investigate rare cetacean records of the north and north-eastern Brazilian coasts

Directory of Open Access Journals (Sweden)

Alexandra Fernandes Costa

2017-08-01

Full Text Available Marine mammal stranding events are used as an important tool for understanding cetacean biology worldwide. Nonetheless, there are vast gaps of knowledge to be filled in for a wide range of species. Reputable information is required regarding species from large baleen whales to sperm and beaked whales, as well as pelagic dolphins. This paper describes new cetacean records from north and north-eastern Brazil, which are both the least surveyed areas regarding aquatic mammals. Regular beach surveys were conducted to recover cetacean carcasses along the coast of Pará beginning November 2005. At the coasts of the Maranhão and Piauí states, the surveys were conducted between 2003 and 2013. From 2003 to 2014, 34 strandings of cetaceans were registered. The study provides four additional species records’ in the area based on strandings (Balaenoptera borealis, Balaenoptera physalus, Peponocephala electra, and Pseudorca crassidens. A mass stranding of Guiana dolphins (Sotalia guianensis, N = 12, the most common species for the region, was reported for the first time. The records presented herein are of special concern, since they expand the knowledge on cetaceans from the Brazilian coast. In addition, this study conducted an analysis to verify the similarity between cetacean compositions described for north and north-eastern Brazil and the southern Caribbean region. The results showed a high similarity between these regions, proving the connection with the Caribbean cetacean fauna.

Habitat use and diel vertical migration of bigeye thresher shark: Overlap with pelagic longline fishing gear.

Science.gov (United States)

Coelho, Rui; Fernandez-Carvalho, Joana; Santos, Miguel N

2015-12-01

Pelagic longliners targeting swordfish and tunas in oceanic waters regularly capture sharks as bycatch, including currently protected species as the bigeye thresher, Alopias superciliosus. Fifteen bigeye threshers were tagged with pop-up satellite archival tags (PSATs) in 2012-2014 in the tropical northeast Atlantic, with successful transmissions received from 12 tags for a total of 907 tracking days. Marked diel vertical movements were recorded on all specimens, with most of the daytime spent in deeper colder water (mean depth = 353 m, SD = 73; mean temperature = 10.7 °C, SD = 1.8) and nighttime spent in warmer water closer to the surface (mean depth = 72 m, SD = 54; mean temperature = 21.9 °C, SD = 3.7). The operating depth of the pelagic longline gear was measured with Minilog Temperature and Depth Recorders (TDRs), and the overlap with habitat utilization was calculated. Overlap is taking place mainly during the night and is higher for juveniles. The results presented herein can be used as inputs for Ecological Risk Assessments for bigeye threshers captured in oceanic tuna fisheries, and serve as a basis for efficient management and conservation of this vulnerable shark species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Boundary separating the seismically active reelfoot rift from the sparsely seismic Rough Creek graben, Kentucky and Illinois

Science.gov (United States)

Wheeler, R.L.

1997-01-01

The Reelfoot rift is the most active of six Iapetan rifts and grabens in central and eastern North America. In contrast, the Rough Creek graben is one of the least active, being seismically indistinguishable from the central craton of North America. Yet the rift and graben adjoin. Hazard assessment in the rift and graben would be aided by identification of a boundary between them. Changes in the strikes of single large faults, the location of a Cambrian transfer zone, and the geographic extent of alkaline igneous rocks provide three independent estimates of the location of a structural boundary between the rift and the graben. The boundary trends north-northwest through the northeastern part of the Fluorspar Area Fault Complex of Kentucky and Illinois, and has no obvious surface expression. The boundary involves the largest faults, which are the most likely to penetrate to hypocentral depths, and the boundary coincides with the geographic change from abundant seismicity in the rift to sparse seismicity in the graben. Because the structural boundary was defined by geologic variables that are expected to be causally associated with seismicity, it may continue to bound the Reelfoot rift seismicity in the future.

Guidelines for ground motion definition for the eastern United States

International Nuclear Information System (INIS)

Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

1985-06-01

Guidelines for the determination of earthquake ground motion definition for the eastern United States are established here. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large- to great-sized earthquakes (M/sub s/ > 7.5) have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes has been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data have been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data, a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the safe shutdown earthquake (SSE). A new procedure for establishing the operating basis earthquake (OBE) is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., figs., tabs

Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

Science.gov (United States)

Sinclair, Elizabeth H; Walker, William A; Thomason, James R

2015-01-01

The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m) is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

Rock-block characterization on regional to local scales for two SKB sites in Forsmark - Uppland and Laxemar - eastern Smaaland, south-eastern Sweden

International Nuclear Information System (INIS)

Beckholmen, Monica; Tiren, Sven A.

2010-11-01

Digital elevation data in 500m, 50m and 10m grids were used for rock-block interpretations at regional, semi-regional and local scales of areas around the two SKB sites, Forsmark and Laxemar, objects for the site-investigation programme. Both areas are interpreted to be close to the surface of the sub- Cambrian peneplain and varying altitude and attitude may testify to blockfaulting in the distorted peneplain. Topographic breaks and changes in the gradient also reveal possible zones of weakness that may conduct water. Rock blocks were constructed for Uppland at 1:750 000, northern Uppland at 1:450 000 and the local Forsmark area at 1:150 000, three sets were constructed for eastern Smaaland at 1:500 000, and one for the semi-regional area at 1:250 000 and one for the local Laxemar area at 1:75 000. The orientation of rock-block boundaries and the size of the rock blocks were treated statistically. The rock blocks/polygons were analysed for their mean, minimum and maximum elevation and the range. The values were displayed by maps. The topography in especially eastern Smaaland is dominated by a clear gradient, the land rising from the sea in the east. Efforts were therefore made to remove an estimated gradient to assess the residual features and the same analyses were then made for mean, maximum, minimum and range values. In many cases the results were enhanced and the two types of presentations are complementary to each other. The rock-block interpretations were compared to bedrock and general correlation between major structures where identified. However, the distribution of rocks on a regional map often demonstrates the plastic deformation in a wider zone. Earthquake epicentres were combined with the rock-block maps and assuming that interpreted rock-block boundaries are fairly steep, there is good agreement between the location of epicentres and rock-block boundaries. In some cases it can be seen how seismic disturbance migrated along a structure. Many

Rock-block characterization on regional to local scales for two SKB sites in Forsmark - Uppland and Laxemar - eastern Smaaland, south-eastern Sweden

Energy Technology Data Exchange (ETDEWEB)

Beckholmen, Monica; Tiren, Sven A. (GEOSIGMA AB (Sweden))

2010-11-15

Digital elevation data in 500m, 50m and 10m grids were used for rock-block interpretations at regional, semi-regional and local scales of areas around the two SKB sites, Forsmark and Laxemar, objects for the site-investigation programme. Both areas are interpreted to be close to the surface of the sub- Cambrian peneplain and varying altitude and attitude may testify to blockfaulting in the distorted peneplain. Topographic breaks and changes in the gradient also reveal possible zones of weakness that may conduct water. Rock blocks were constructed for Uppland at 1:750 000, northern Uppland at 1:450 000 and the local Forsmark area at 1:150 000, three sets were constructed for eastern Smaaland at 1:500 000, and one for the semi-regional area at 1:250 000 and one for the local Laxemar area at 1:75 000. The orientation of rock-block boundaries and the size of the rock blocks were treated statistically. The rock blocks/polygons were analysed for their mean, minimum and maximum elevation and the range. The values were displayed by maps. The topography in especially eastern Smaaland is dominated by a clear gradient, the land rising from the sea in the east. Efforts were therefore made to remove an estimated gradient to assess the residual features and the same analyses were then made for mean, maximum, minimum and range values. In many cases the results were enhanced and the two types of presentations are complementary to each other. The rock-block interpretations were compared to bedrock and general correlation between major structures where identified. However, the distribution of rocks on a regional map often demonstrates the plastic deformation in a wider zone. Earthquake epicentres were combined with the rock-block maps and assuming that interpreted rock-block boundaries are fairly steep, there is good agreement between the location of epicentres and rock-block boundaries. In some cases it can be seen how seismic disturbance migrated along a structure. Many

Sedimentary phosphorus dynamics and the evolution of bottom-water hypoxia: A coupled benthic­pelagic model of a coastal system

NARCIS (Netherlands)

Reed, D.C.; Slomp, C.P.; Gustafsson, B.G.

2011-01-01

The present study examines oxygen and phosphorus dynamics at a seasonally hypoxic site in the Arkona basin of the Baltic Sea. A coupled benthic–pelagic reactive-transport model is used to describe the evolution of bottom-water solute concentrations, as well as pore-water and sediment profiles.

Identification of Photosynthesis Inhibitors of Pelagic Marine Algae Using 96-Well Plate Microfractionation for Enhanced Throughput in Effect-Directed Analysis

NARCIS (Netherlands)

Booij, P.; Vethaak, A D; Leonards, P E; Sjollema, S B; Kool, J.; de Voogt, P; Lamoree, M H

2014-01-01

Because of large-scale production and use of an increasing diversity of chemicals in modern society, estuarine and coastal waters may be contaminated with numerous substances. Some of these compounds have the potential to affect microalgae at the base of the pelagic food chain. Therefore, we

Selection of geohydrologic boundaries for ground-water flow models, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Downey, J.S.; Gutentag, E.D.; Kolm, K.E.

1990-01-01

The conceptual ground-water model of the southern Nevada/Death Valley, California region presented in this paper includes two aquifer systems: a shallow, intermontane, mostly unconfined aquifer composed of unconsolidated or poorly consolidated sediments and consolidated, layered volcanics, and a deep, regional multiple-layered, confined aquifer system composed of faulted and fractured carbonate and volcanic rocks. The potentiometric surfaces of both aquifer systems indicate that ground water leaks vertically from the deeper to the shallower geologic units, and that water in the shallower aquifer may not flow beyond the intermontane subbasin, whereas water in the deeper aquifer may indicate transbasinal flow to the playas in Death Valley. Most of the hydrologic boundaries of the regional aquifer systems in the Yucca Mountain region are geologically complex. Most of the existing numerical models simulating the ground-water flow system in the Yucca Mountain region are based on limited potentiometric-head data elevation and precipitation estimates, and simplified geology. These models are two-dimensional, and are not adequate. The alternative approach to estimating unknown boundary conditions for the regional ground-water flow system involves the following steps: (1) Incorporate known boundary-conditions data from the playas in Death Valley and the Ash Meadows spring line; (2) use estimated boundary data based on geological, pedological, geomorphological, botanical, and hydrological observations; (3) test these initial boundary conditions with three-dimensional models, both steady-state and transient; (4) back-calculate the boundary conditions for the northern, northwestern, northeastern and eastern flux boundaries; (5) compare these calculated values with known data during model calibration steps; and (6) adjust the model. 9 refs., 6 figs

Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales

DEFF Research Database (Denmark)

Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M.

2013-01-01

In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly......, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted....

Defining seascapes for marine unconsolidated shelf sediments in an eastern boundary upwelling region: The southern Benguela as a case study

Science.gov (United States)

Karenyi, Natasha; Sink, Kerry; Nel, Ronel

2016-02-01

Marine unconsolidated sediment habitats, the largest benthic ecosystem, are considered physically controlled ecosystems driven by a number of local physical processes. Depth and sediment type are recognised key drivers of these ecosystems. Seascape (i.e., marine landscape) habitat classifications are based solely on consistent geophysical features and provide an opportunity to define unconsolidated sediment habitats based on processes which may vary in distribution through space and time. This paper aimed to classify unconsolidated sediment seascapes and explore their diversity in an eastern boundary upwelling region at the macro-scale, using the South African west coast as a case study. Physical variables such as sediment grain size, depth and upwelling-related variables (i.e., maximum chlorophyll concentration, austral summer bottom oxygen concentration and sediment organic carbon content) were included in the analyses. These variables were directly measured through sampling, or collated from existing databases and the literature. These data were analysed using multivariate Cluster, Principal Components Ordination and SIMPER analyses (in PRIMER 6 + with PERMANOVA add-in package). There were four main findings; (i) eight seascapes were identified for the South African west coast based on depth, slope, sediment grain size and upwelling-related variables, (ii) three depth zones were distinguished (inner, middle and outer shelf), (iii) seascape diversity in the inner and middle shelves was greater than the outer shelf, and (iv) upwelling-related variables were responsible for the habitat diversity in both inner and middle shelves. This research demonstrates that the inclusion of productivity and its related variables, such as hypoxia and sedimentary organic carbon, in seascape classifications will enhance the ability to distinguish seascapes on continental shelves, where productivity is most variable.

“Marine eutrophication is the process of enrich- ment of marine ...

African Journals Online (AJOL)

spamer

into a protected shallow water environment (Fig. 1) which is ... cent discharge of nitrogen from pelagic fish processing waste. It is suggested .... from deep eastern Pacific Ocean). Published ... temporal variability signal to be defined. Second ...

On the Crossover of Boundary Currents in an Idealized Model of the Red Sea

KAUST Repository

Zhai, Ping

2015-05-01

© 2015 American Meteorological Society. The west-to-east crossover of boundary currents has been seen in mean circulation schemes from several past models of the Red Sea. This study investigates the mechanisms that produce and control the crossover in an idealized, eddy-resolving numerical model of the Red Sea. The authors also review the observational evidence and derive an analytical estimate for the crossover latitude. The surface buoyancy loss increases northward in the idealized model, and the resultant mean circulation consists of an anticyclonic gyre in the south and a cyclonic gyre in the north. In the midbasin, the northward surface flow crosses from the western boundary to the eastern boundary. Numerical experiments with different parameters indicate that the crossover latitude of the boundary currents changes with f0, β, and the meridional gradient of surface buoyancy forcing. In the analytical estimate, which is based on quasigeostrophic, β-plane dynamics, the crossover is predicted to lie at the latitude where the net potential vorticity advection (including an eddy component) is zero. Various terms in the potential vorticity budget can be estimated using a buoyancy budget, a thermal wind balance, and a parameterization of baroclinic instability.

The Chicxulub impact is synchronous with the planktonic foraminifera mass extinction at the Cretaceous/Paleogene boundary: new evidence from the Moncada section, Cuba

Energy Technology Data Exchange (ETDEWEB)

Arenillas, I.; Arz, J.A.; Grajales-Nishimura, J.M.; Melendez, A.; Rojas-Consuegra, R.

2016-07-01

The Moncada section, western Cuba, is one of the few sections across the Cretaceous/Paleogene (K/Pg) boundary in the Gulf of Mexico and Caribbean where an Ir anomaly has been identified toward and above the top of a clastic unit, locally called the Moncada Formation (Fm.). The Moncada Fm. is enriched in ejecta (altered glass spherules, shocked quartz, melt rock fragments, etc.) and represents the local Complex Clastic Unit (CCU) linked to the Chicxulub impact event. This CCU is overlain by a 2-3cm thick bed of Ir-rich, dark, calcareous claystone which represents the “K/T Boundary Clay” at Moncada. All lowermost Danian Planktonic Foraminiferal zones and Acme-Stages (PFAS) were identified, suggesting stratigraphic continuity across the Danian and indicating that the Moncada Fm. is K/Pg boundary in age. High-resolution biostratigraphic data suggest that the mass extinction event of planktonic foraminifera at the K/Pg boundary was more severe than previously suggested. The absence of cosmopolitan, generalist Cretaceous species in the Danian deposits of Moncada supports the hypothesis that only Guembelitria survived the mass extinction triggered by the Chicxulub impact event. The high Ir-concentration and the ejecta-rich clay laminations identified in the lowermost Danian of Moncada (Ancón Fm.) are explained partly as the redeposition of ejecta material eroded and reworked from higher topographic levels, still contaminated by toxic trace elements (e.g., Cu and Ni) of meteoritic origin. These pollutants of meteoritic origin could have affected the ecological conditions of the pelagic environment for thousands of years after the K/Pg boundary, being particularly intense just after the Chicxulub impact. The ecological stress due to the pollutants partly explains the catastrophic mass extinction of planktonic foraminifera at the K/Pg boundary and their subsequent evolutionary radiation. (Author)

Hydroxylamine hydrochloride-acetic acid-soluble and -insoluble fractions of pelagic sediment: Readsorption revisited

Science.gov (United States)

Piper, D.Z.; Wandless, G.A.

1992-01-01

The extraction of the rare earth elements (REE) from deep-ocean pelagic sediment, using hydroxylamine hydrochloride-acetic acid, leads to the separation of approximately 70% of the bulk REE content into the soluble fraction and 30% into the insoluble fraction. The REE pattern of the soluble fraction, i.e., the content of REE normalized to average shale on an element-by-element basis and plotted against atomic number, resembles the pattern for seawater, whereas the pattern, as well as the absolute concentrations, in the insoluble fraction resembles the North American shale composite. These results preclude significant readsorption of the REE by the insoluble phases during the leaching procedure.

Seasonal and interannual variations in pigments in the Adriatic Sea

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

30m), depends on the freshwater inflow as well ... The Adriatic Sea (Northern Mediterranean) and location of satellite pigment data (cross marks) ..... landings of small pelagic fish in the eastern Adriatic– ... and North America (1858–1980).

Footprints, Imprints: Seeing Environmentalist and Buddhist Marie Byles as an Eastern Australian

Directory of Open Access Journals (Sweden)

Allison Jane Cadzow

2007-01-01

Full Text Available This paper looks at the Australian author, traveller, conservationist and Buddhist Marie Byles (1900-1979 as “eastern” and Australian at once. It investigates the influence of Buddhist spirituality and travel on her approach to the environment and explores some possibilities arising from looking at her work as part of a broader transnational humanitarian and intellectual identification, moving beyond ethnicity based boundaries. Thinking about eastern Australian identities can encourage consideration of Australia in Asia, Australia as Asian, connections across seas, and links and differences within Australia. The paper explores Marie Byles as an eastern Australian by considering her travel in Sydney and the region (in Australia, China, Vietnam, India and Burma from the 1930s to the 1960s, the design and use of her home as a hub for early Buddhist meetings, her publication of texts discussing Eastern philosophy, and her environmental activism. Throughout the discussion Byles’s understanding of power relations, derived from an entwining of feminist and socialist ideas, a pacifist and Buddhist/spiritualist revaluation of environments emerges. From these influences she provided challenges to her fellow walkers, environmentalists, and society at large to rethink relationships with nature and each other, insights that have yet to be adequately explored and recognised.

Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

KAUST Repository

Tsiola, A.

2015-12-01

The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.

The major tectonic boundaries of the Northern Red Sea rift, Egypt derived from geophysical data analysis

Science.gov (United States)

Saleh, Salah; Pamukçu, Oya; Brimich, Ladislav

2017-09-01

In the present study, we have attempted to map the plate boundary between Arabia and Africa at the Northern Red Sea rift region including the Suez rift, Gulf of Aqaba-Dead Sea transform and southeastern Mediterranean region by using gravity data analysis. In the boundary analysis method which was used; low-pass filtered gravity anomalies of the Northern Red Sea rift region were computed. Different crustal types and thicknesses, sediment thicknesses and different heat flow anomalies were evaluated. According to the results, there are six subzones (crustal blocks) separated from each other by tectonic plate boundaries and/or lineaments. It seems that these tectonic boundaries reveal complex structural lineaments, which are mostly influenced by a predominant set of NNW-SSE to NW-SE trending lineaments bordering the Red Sea and Suez rift regions. On the other side, the E-W and N-S to NNE-SSW trended lineaments bordering the South-eastern Mediterranean, Northern Sinai and Aqaba-Dead Sea transform regions, respectively. The analysis of the low pass filtered Bouguer anomaly maps reveals that the positive regional anomaly over both the Red Sea rift and South-eastern Mediterranean basin subzones are considered to be caused by the high density of the oceanic crust and/or the anomalous upper mantle structures beneath these regions whereas, the broad medium anomalies along the western half of Central Sinai with the Suez rift and the Eastern Desert subzones are attributed to low-density sediments of the Suez rift and/or the thick upper continental crustal thickness below these zones. There are observable negative anomalies over the Northern Arabia subzone, particularly in the areas covered by Cenozoic volcanics. These negative anomalies may be attributed to both the low densities of the surface volcanics and/or to a very thick upper continental crust. On the contrary, the negative anomaly which belongs to the Gulf of Aqaba-Dead Sea transform zone is due to crustal thickening

Patterns of variations in large pelagic fish: A comparative approach between the Indian and the Atlantic Oceans

Science.gov (United States)

Corbineau, A.; Rouyer, T.; Fromentin, J.-M.; Cazelles, B.; Fonteneau, A.; Ménard, F.

2010-07-01

Catch data of large pelagic fish such as tuna, swordfish and billfish are highly variable ranging from short to long term. Based on fisheries data, these time series are noisy and reflect mixed information on exploitation (targeting, strategy, fishing power), population dynamics (recruitment, growth, mortality, migration, etc.), and environmental forcing (local conditions or dominant climate patterns). In this work, we investigated patterns of variation of large pelagic fish (i.e. yellowfin tuna, bigeye tuna, swordfish and blue marlin) in Japanese longliners catch data from 1960 to 2004. We performed wavelet analyses on the yearly time series of each fish species in each biogeographic province of the tropical Indian and Atlantic Oceans. In addition, we carried out cross-wavelet analyses between these biological time series and a large-scale climatic index, i.e. the Southern Oscillation Index (SOI). Results showed that the biogeographic province was the most important factor structuring the patterns of variability of Japanese catch time series. Relationships between the SOI and the fish catches in the Indian and Atlantic Oceans also pointed out the role of climatic variability for structuring patterns of variation of catch time series. This work finally confirmed that Japanese longline CPUE data poorly reflect the underlying population dynamics of tunas.

Transuranic concentrations in reef and pelagic fish from the Marshall Islands. [/sup 239/Pu, /sup 240/Pu

Energy Technology Data Exchange (ETDEWEB)

Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Jokela, T.A.

1980-09-01

Concentrations of /sup 239 + 240/Pu are reported in tissues of several species of reef and pelagic fish caught at 14 different atolls in the northern Marshall Islands. Several regularities that are species dependent are evident in the distribution of /sup 239 + 240/Pu among different body tissues. Concentrations in liver always exceeded those in bone and concentrations were lowest in the muscle of all fish analyzed. A progressive discrimination against /sup 239 + 240/Pu was observed at successive trophic levels at all atolls except Bikini and Enewetak, where it was difficult to conclude if any real difference exists between the average concentration factor for /sup 239 + 240/Pu among all fish, which include bottom feeding and grazing herbivores, bottom feeding carnivores, and pelagic carnivores from different atoll locations. The average concentration of /sup 239 + 240/Pu in the muscle of surgeonfish from Bikini and Enewetak was not significantly different from the average concentrations determined in these fish at the other, lesser contaminated atolls. Concentrations among all 3rd, 4th, and 5th trophic level species are highest at Bikini where higher environmental concentrations are found. The reasons for the anomalously low concentrations in herbivores from Bikini and Enewetak are not known.

Identification of photosynthesis inhibitors of pelagic marine algae using 96 well plate micro-fractionation for enhanced throughput in Effect-Directed Analysis

NARCIS (Netherlands)

Booij, A.; Vethaak, A.D.; Leonards, P.E.G.; Sjollema, S.B.; Kool, J.; de Voogt, P.; Lamoree, M.H.

2014-01-01

Because of large-scale production and use of an increasing diversity of chemicals in modern society, estuarine and coastal waters may be contaminated with numerous substances. Some of these compounds have the potential to affect microalgae at the base of the pelagic food chain. Therefore, we

Filtration of submicrometer particles by pelagic tunicates.

Science.gov (United States)

Sutherland, Kelly R; Madin, Laurence P; Stocker, Roman

2010-08-24

Salps are common in oceanic waters and have higher per-individual filtration rates than any other zooplankton filter feeder. Although salps are centimeters in length, feeding via particle capture occurs on a fine, mucous mesh (fiber diameter d approximately 0.1 microm) at low velocity (U = 1.6 +/- 0.6 cmxs(-1), mean +/- SD) and is thus a low Reynolds-number (Re approximately 10(-3)) process. In contrast to the current view that particle encounter is dictated by simple sieving of particles larger than the mesh spacing, a low-Re mathematical model of encounter rates by the salp feeding apparatus for realistic oceanic particle-size distributions shows that submicron particles, due to their higher abundances, are encountered at higher rates (particles per time) than larger particles. Data from feeding experiments with 0.5-, 1-, and 3-microm diameter polystyrene spheres corroborate these findings. Although particles larger than 1 microm (e.g., flagellates, small diatoms) represent a larger carbon pool, smaller particles in the 0.1- to 1-microm range (e.g., bacteria, Prochlorococcus) may be more quickly digestible because they present more surface area, and we find that particles smaller than the mesh size (1.4 microm) can fully satisfy salp energetic needs. Furthermore, by packaging submicrometer particles into rapidly sinking fecal pellets, pelagic tunicates can substantially change particle-size spectra and increase downward fluxes in the ocean.

Guidelines for earthquake ground motion definition for the eastern United States

International Nuclear Information System (INIS)

Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

1985-01-01

Guidelines for the determination of earthquake ground-motion definition for the eastern United States are established in this paper. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large to great (M > 7.5) sized earthquakes have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes have been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data has been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the Safe Shutdown Earthquake, SSE. A new procedure for establishing the Operating Basis Earthquake, OBE, is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., 2 figs., 1 tab

The submarine volcano eruption off El Hierro Island: Effects on the scattering migrant biota and the evolution of the pelagic communities

KAUST Repository

Ariza, Alejandro

2014-07-21

The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. © 2014 Ariza et al.

The rheological structure of the lithosphere in the Eastern Marmara region, Turkey

Science.gov (United States)

Oruç, Bülent; Sönmez, Tuba

2017-05-01

The aim of this work is to propose the geometries of the crustal-lithospheric mantle boundary (Moho) and lithosphere-asthenosphere boundary (LAB) and the 1D thermal structure of the lithosphere, in order to establish a rheological model of the Eastern Marmara region. The average depths of Moho and LAB are respectively 35 km and 51 km from radially averaged amplitude spectra of EGM08 Bouguer anomalies. The geometries of Moho and LAB interfaces are estimated from the Parker-Oldenburg gravity inversion algorithm. Our results show the Moho depth varies from 31 km at the northern part of North Anatolian Fault Zone (NAFZ) to 39 km below the mountain belt in the southern part of the NAFZ. The depth to the LAB beneath the same parts of the region ranges from 45 km to 55 km. Having lithospheric strength and thermal boundary layer structure, we analyzed the conditions of development of lithosphere thinning. A two-dimensional strength profile has been estimated for rheology model of the study area. Thus we suggest that the rheological structure consists of a strong upper crust, a weak lower crust, and a partly molten upper lithospheric mantle.

210Po and 210Pb in a pelagic trophic chain

International Nuclear Information System (INIS)

Radakovitch, O.; Strady, E.; Veron, A.; Chiffoleau, J.F.; Tronczynski, J.; Harmelin-Vivien, M.

2013-01-01

The ANR-COSTAS program studied the bioaccumulation and biomagnification of organic and inorganic contaminants through the trophic chains of two small pelagic fish, anchovy and sardine, on the continental shelf of the Gulf of Lion (Northwestern Mediterranean Sea). 210 Po and 210 Pb were analysed at various levels of this trophic chain, as well as trace metal elements, lead isotopes and C and N isotopes which provide additional information on both biogeochemical cycles and trophic transfer. To our knowledge, this is the first time that an entire trophic chain is analysed for these two radionuclides. Water, suspended particles, phytoplankton and zooplankton were collected at 7 stations during two contrast seasons. Phyto and zooplankton were separated in 6 classes through size-sieving: 6-60 μm; 60-200; 200-500; 500-1000; 1000-2000 and > 2000 μm. Anchovy and sardine were collected also two times and analyses were performed on muscle and liver independently for both sexes

Benthic Foraminifera, Food in the Deep Sea, and Limits to Bentho-Pelagic Coupling

Science.gov (United States)

Thomas, E.; Boscolo-Galazzo, F.; Arreguin-Rodrigu, G. J.; Ortiz, S.; Alegret, L.

2015-12-01

The deep-sea is the largest habitat on Earth, contains highly diverse biota, but is very little known. Many of its abundant benthic biota (e.g., nematodes) are not preserved in the fossil record. Calcareous and agglutinated benthic foraminifera (unicellular eukaryotes, Rhizaria; efficient dispersers) and ostracodes (Animalia, Crustacea; non-efficient dispersers) are the most common organisms providing a fossil record of deep-sea environments. Very little food is supplied to the deep-sea, because organic matter produced by photosynthesis is largely degraded before it arrives at the seafloor. Only a few % of organic matter is carried to the ocean bottom by 'marine snow', with its particle size and behavior in the water column controlled by surface ecosystem structure, including type of dominant primary producers (diatoms, cyanobacteria). Food supply and its seasonality are generally seen as the dominant control on benthic assemblages (combined with oxygenation), providing bentho-pelagic coupling between primary and benthic productivity. Benthic foraminiferal assemblages (composition and density) thus are used widely to estimate past productivity, especially during episodes of global climate change, ocean acidification, and mass extinction of primary producers. We show that some environmental circumstances may result in interrupting bentho-pelagic coupling, e.g. through lateral supply of organic matter along continental margins (adding more refractory organic matter), through trophic focusing and/or fine particle winnowing on seamounts (giving an advantage to suspension feeders), and through carbonate undersaturation (giving advantage to infaunal over epifaunal calcifyers). In addition, increased remineralization of organic matter combined with increased metabolic rates may cause assemblages to reflect more oligotrophic conditions at stable primary productivity during periods of global warming. As a result, benthic foraminiferal accumulation rates must be carefully

Assessing health literacy in the eastern and middle-eastern cultures

Directory of Open Access Journals (Sweden)

Satish Chandrasekhar Nair

2016-08-01

Full Text Available Abstract Background Health literacy is a term employed to assess the ability of people to meet the increasing demands related to health in a rapidly evolving society. Low health literacy can affect the social determinants of health, health outcomes and the use of healthcare services. The purpose of the study was to develop a survey construct to assess health literacy within the context of regional culture. Different socioeconomic status among the Eastern and Middle Eastern countries may restrict, health information access and utilization for those with low literacy. Methods By employing expert panel, Delphi technique, focus group methodologies, and pre-testing using participants (N = 900 from the UAE and India, a survey construct to the Eastern-Middle Eastern cultures was developed. Reliability was assessed using Cronbach’s α and validity using Factor analysis. Kiaser-Meyer-Olkin (KMO sampling adequacy and Bartlett’s tests were used to assess the strength of the relationship among the variables. Results Inclusion of non-health related items were found to be critical in the authentic assessment of health literacy in the Eastern and Middle Eastern population given the influence of social desirability. Thirty-two percentage of the original 19-item construct was eliminated by the focus group for reasons of relevance and impact for the local culture. Field pretesting participants from two countries, indicated overall construct reliability (Cronbach’s α =0.85, validity and consistency (KMO value of 0.92 and Bartlett’s test of sphericity was significant. Conclusion The Eastern-Middle Eastern Adult Health Literacy (EMAHL13, screening instrument is brief, simple, a useful indicator of whether or not a patient can read. It assessespatients’ ability to comprehend by distinguishing between health and non-health related items. The EMAHL13 will be a useful too for the reliable assessment of health literacy in countries, where culture plays a

Assessing health literacy in the eastern and middle-eastern cultures.

Science.gov (United States)

Nair, Satish Chandrasekhar; Satish, Karthyayani Priya; Sreedharan, Jayadevan; Ibrahim, Halah

2016-08-19

Health literacy is a term employed to assess the ability of people to meet the increasing demands related to health in a rapidly evolving society. Low health literacy can affect the social determinants of health, health outcomes and the use of healthcare services. The purpose of the study was to develop a survey construct to assess health literacy within the context of regional culture. Different socioeconomic status among the Eastern and Middle Eastern countries may restrict, health information access and utilization for those with low literacy. By employing expert panel, Delphi technique, focus group methodologies, and pre-testing using participants (N = 900) from the UAE and India, a survey construct to the Eastern-Middle Eastern cultures was developed. Reliability was assessed using Cronbach's α and validity using Factor analysis. Kiaser-Meyer-Olkin (KMO) sampling adequacy and Bartlett's tests were used to assess the strength of the relationship among the variables. Inclusion of non-health related items were found to be critical in the authentic assessment of health literacy in the Eastern and Middle Eastern population given the influence of social desirability. Thirty-two percentage of the original 19-item construct was eliminated by the focus group for reasons of relevance and impact for the local culture. Field pretesting participants from two countries, indicated overall construct reliability (Cronbach's α =0.85), validity and consistency (KMO value of 0.92 and Bartlett's test of sphericity was significant). The Eastern-Middle Eastern Adult Health Literacy (EMAHL13), screening instrument is brief, simple, a useful indicator of whether or not a patient can read. It assessespatients' ability to comprehend by distinguishing between health and non-health related items. The EMAHL13 will be a useful too for the reliable assessment of health literacy in countries, where culture plays a significant impact. This will be the first steptowards providing

A Study of the Pelagic Larval Duration of Acropora humilis, Coral Recruitment and Connectivity in the Saudi Arabian Red Sea

KAUST Repository

Khalil, Maha

2011-12-12

Combined knowledge of the pelagic larval duration of coral species and coral recruitment patterns can provide evidence of inter-reef connectivity and indicate a reef’s ability to recover. We attempted to determine the maximum pelagic larval duration of Acropora humilis. Larvae were reared in a controlled environment unfavorable for settlement. The larvae lived in a pelagic state for a maximum of 29 days, although this is probably an underestimate of actual longevity for this species. Given the information available from the literature with respect to larval dispersal rates, it is not expected that larvae with this longevity will disperse further than 10-20 km from their natal reef, if at all. A long-term recruitment monitoring project was also set up on Abu Shosha Reef, which suffered nearly complete coral loss due to a bleaching event in summer of 2010. In April 2011, 60 settlement plates were placed on the reef. In July, a total of 102 living scleractinian recruits were counted on the plates. While pocilloporids were the most dominant recruits on the reef (57.8%), about 20.6% of living recruits belonged to Acroporidae, a family whose live cover on the reef is extremely low (0.67%). However, the overall mean density of recruits was very low (1.7 living recruits/100cm2) compared to similar studies around the world despite the spawning season having just ended. Fish surveys showed herbivore biomass to be very low compared to other reef systems in the world, but densities were significantly higher than another reef in the Red Sea with about 10 times more live coral cover. Recovery from bleaching for Abu Shosha and similar reefs in the region may be very slow relative to rates observed in other parts of the world if recruitment rates and herbivore communities remain low.

STURM: Resuspension mesocosms with realistic bottom shear stress and water column turbulence for benthic-pelagic coupling studies: Design and Applications

Science.gov (United States)

Sanford, L. P.; Porter, E.; Porter, F. S.; Mason, R. P.

2016-02-01

Shear TUrbulence Resuspension Mesocosm (STURM) tanks, with high instantaneous bottom shear stress and realistic water column mixing in a single system, allow more realistic benthic-pelagic coupling studies that include sediment resuspension. The 1 m3 tanks can be programmed to produce tidal or episodic sediment resuspension over extended time periods (e.g. 4 weeks), over muddy sediments with or without infaunal organisms. The STURM tanks use a resuspension paddle that produces uniform bottom shear stress across the sediment surface while gently mixing a 1 m deep overlying water column. The STURM tanks can be programmed to different magnitudes, frequencies, and durations of bottom shear stress (and thus resuspension) with proportional water column turbulence levels over a wide range of mixing settings for benthic-pelagic coupling experiments. Over eight STURM calibration settings, turbulence intensity ranged from 0.55 to 4.52 cm s-1, energy dissipation rate from 0.0032 to 2.65 cm2 s-3, the average bottom shear stress from 0.0068 to 0.19 Pa, and the instantaneous bottom shear stress from 0.07 to 2.0 Pa. Mixing settings can be chosen as desired and/or varied over the experiment, based on the scientific question at hand. We have used the STURM tanks for four 4-week benthic-pelagic coupling ecosystem experiments with tidal resuspension with or without infaunal bivalves, for stepwise erosion experiments with and without infaunal bivalves, for experiments on oyster biodeposit resuspension, to mimic storms overlain on tidal resuspension, and for experiments on the effects of varying frequency and duration of resuspension on the release of sedimentary contaminants. The large size of the tanks allows water quality and particle measurements using standard oceanographic instrumentation. The realistic scale and complexity of the contained ecosystems has revealed indirect feedbacks and responses that are not observable in smaller, less complex experimental systems.

Southern limits of distribution of the intertidal gobies Chaenogobius annularis and C. gulosus support the existence of a biogeographic boundary in southern Japan (Teleostei, Perciformes, Gobiidae

Directory of Open Access Journals (Sweden)

Atsunobu Murase

2017-12-01

Full Text Available Understanding the distributional patterns of individual animal groups with respect to coastal topology and the local physical environment provides essential foundational frameworks for marine zoogeography. In the northwestern Pacific waters of Japan, the distributional pattern of some cool-temperate species of marine fishes suggests the existence of a biogeographic boundary corresponding to a long sandy shore on the eastern coast of Kyushu, southern Japan. The existence of this hypothetical biogeographic boundary was tested by mapping the southern distributional limit of two species of cool-temperate intertidal gobies, Chaenogobius annularis and C. gulosus, which are endemic to East Asia and common in rock pools within their range in the Japanese Archipelago. Distribution and abundance were assessed by survey of museum collections from south-east Kyushu (i.e., the entire coasts of Kagoshima and Miyazaki prefectures; and a quantitative survey of the abundance of these gobies in rock pools at various sites around the hypothesized boundary on the eastern coast of Kyushu, including the subtropical Tanega-shima Island. The museum collection survey showed different distribution patterns between the two species: C. annularis was distributed along the entire coasts of south-east Kyushu including subtropical islands, whereas C. gulosus was distributed along these coasts, including one site on a subtropical island, except for an area south of the hypothesized boundary on the eastern coast of Kyushu. The density and occurrence rates of C. annularis in rock pools decreased with latitude, it being absent from a subtropical island, and C. gulosus was not detected from sites south of the hypothesized boundary. The qualitative survey showed that the southernmost records of C. annularis and C. gulosus were the adjacent subtropical islands (Yaku-shima and Tanega-shima islands respectively, although the quantitative survey suggested that their normal range of

Altimeter-derived flow field over a newly identified coastal ocean boundary in the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Antony, M.K.; Somayajulu, Y.K.; Swamy, G.N.

part, tapers off towards north and bulges towards south. In the present communication, the T/P-derived flow pattern over this new boundary is presented. The derived flow pattern shows the general dominance of meso-scale eddies in the Arabian Sea...

Eastern Europe

International Nuclear Information System (INIS)

Baret, J.P.; Corcuff, A.; Jousten, M.; Cherie, J.B.; Gorge, X.; Augustin, X.; Belime, F.

1999-01-01

By its economical and political impact, nuclear energy has an important contribution the countries of Eastern Europe that goes beyond simple energy source. The most important challenge is to gain a safety culture. Improvements have been noted but the reactors safety must stay a priority of the international cooperation in Eastern Europe. The plan for the completion and improvement of Mochovce nuclear plant is described, the situation of Chernobyl and how to make the sarcophagus in safe is discussed, the experience of a french P.M.E. ( small and medium size firm) called Corys Tess that has chosen to position itself on the Eastern Europe nuclear market is related. (N.C.)

Nutrient co-limitation at the boundary of an oceanic gyre

Science.gov (United States)

Browning, Thomas J.; Achterberg, Eric P.; Rapp, Insa; Engel, Anja; Bertrand, Erin M.; Tagliabue, Alessandro; Moore, C. Mark

2017-11-01

Nutrient limitation of oceanic primary production exerts a fundamental control on marine food webs and the flux of carbon into the deep ocean. The extensive boundaries of the oligotrophic sub-tropical gyres collectively define the most extreme transition in ocean productivity, but little is known about nutrient limitation in these zones. Here we present the results of full-factorial nutrient amendment experiments conducted at the eastern boundary of the South Atlantic gyre. We find extensive regions in which the addition of nitrogen or iron individually resulted in no significant phytoplankton growth over 48 hours. However, the addition of both nitrogen and iron increased concentrations of chlorophyll a by up to approximately 40-fold, led to diatom proliferation, and reduced community diversity. Once nitrogen-iron co-limitation had been alleviated, the addition of cobalt or cobalt-containing vitamin B12 could further enhance chlorophyll a yields by up to threefold. Our results suggest that nitrogen-iron co-limitation is pervasive in the ocean, with other micronutrients also approaching co-deficiency. Such multi-nutrient limitations potentially increase phytoplankton community diversity.

The Development of Russian Far East and Eastern Siberia and the Future of Northeast Asia

Directory of Open Access Journals (Sweden)

Ha Yong-Chool

2013-06-01

Full Text Available The purpose of this short paper is to introduce a new concept and way of thinking about the future of Northeast Asia in conjunction with the development of Russian Far East and Eastern Siberia. The basic arguments of this paper are: first, the specialists should shed the conventional definition of geographical boundaries, especially in defining Northeast Asia; second, Russia’s Far Eastern development can make a significant contribution to the regional community building depending on how creatively and imaginatively the development proceeds; lastly, it is high time to start preparation for the future of Northeast Asia before it gets too late. In this regard, at the end of this paper the authors introduce their initial effort to establish a consortium, the purpose of which is to lay groundwork for the establishment of an institute for Northeast Asian community building

Unlocking the hydrocarbon potential of the eastern Black Sea basin. Prospectivity of middle Miocene submarine fan reservoirs by seismic sequence stratigraphy

International Nuclear Information System (INIS)

Gundogan, Coskun; Galip, Ozbek; Ali, Demirer

2002-01-01

Full text : The objective of this paper is to present present depositional characteristics and hydrocarbon prospectivity of the middle Miocene submarine basin floor fan deposits from the exploration stand point of view by using seismic data available in the offshore eastern Black Sea basin. This basin is a Tertiary trough formed as a continuation of the Mesozoic oceanic basin. The hydrocarbon potential of the basin is believed to be high in the Tertiary section because of the existence of the elements necessary for generation, migration and entrapment of hydrocarbon. A sequence stratigraphic study has been carried out by using 2-d seismic data in the Turkish portion of the eastern Black Sea basin. The objective of the study was to determine periods of major clastic sediment influxes which might lead to identify good reservoir intervals and their spatial distribution in this basin. All basic seismic sequence stratigraphic interpretation techniques and seismic facies analysis were used to identify times of these sand rich deposition periods. Sequence stratigraphy and seismic facies analysis indicate that the basinal areas of the middle Miocene sequences were dominated mainly by submarine fan complexes introduced in the lowstand stages and pelagic sediments deposited during the transgressive and highstand stages. It was proposed that Turkish portion of this basin which is one of the best frontier exploration area with its high potential left in the world, is glimpsing to those looking for good future exploration opportunities.

The role of pelagic-benthic coupling in structuring littoral benthic communities at Terra Nova Bay (Ross Sea and in the Straits of Magellan

Directory of Open Access Journals (Sweden)

Riccardo Cattaneo-Vietti

1999-12-01

Full Text Available In Antarctic and peri-Antarctic regions, benthic communities are persistent in time and show high biomass and large numbers of individuals, mainly consisting of suspension and deposit feeders. In fact, apart from recruitment, the major factor structuring these communities is the high flow of organic matter from the pelagic domain to the bottom, representing an important energy source for the benthic organisms. The aim of this paper is to review, compile and compare the data from earlier investigations in Terra Nova Bay (Ross Sea and the Straits of Magellan, in order to come to a more general conclusion about the role of the pelagic-benthic coupling in structuring littoral benthic communities in southern coastal areas. Few measurements of flux rates and the biochemical composition of the sinking particles occurring in Antarctic and peri-Antarctic shallow waters are available, but a compilation of our own data and others allows a comparison of these two systems. The different environmental conditions between Antarctica and the Straits of Magellan lead to differences in the origin of the particulate organic matter and in its biochemical composition, and consequently in the coupling between pelagic and benthic domains. At Terra Nova Bay the summer particulate matter shows a high labile fraction of a good food value: its flux has been evaluated at about 0.67 g m-2d-1. Conversely, the Straits of Magellan show multi-structured ecosystems where the quality and quantity of the organic matter flux towards the bottom change according to the local geomorphology and current dynamics. Moreover, the three-dimensional assemblages of suspension-feeders, so common in Antarctic shallow waters, seem to be absent in the Magellan area. In particular sponges, gorgonarians and bryozoans play a secondary role inside the Straits of Magellan, where polychaetes (60% and molluscs (9-10% are dominant on soft bottoms, and where they reach high values in density and biomass

Vulnerability of oceanic sharks as pelagic longline bycatch

Directory of Open Access Journals (Sweden)

A.J. Gallagher

2014-08-01

Full Text Available Bycatch (the unintentional catch of non-target species or sizes is consistently ranked as one of the greatest threats to marine fish populations; yet species-specific rates of bycatch survival are rarely considered in risk assessments. Regulations often require that bycatch of threatened species be released; but, if animals are already dead, their release serves no conservation purpose. We examined the survival of 12 shark species caught as bycatch in the US Atlantic pelagic longline fishery. Shark survival was evaluated in relation to fishery target (swordfish versus tuna and four operational, environmental, and biological variables to evaluate the underlying mechanisms affecting mortality. Survival estimates ranged from 33% (night shark to 97% (tiger shark with seven of the 12 species being significantly affected by at least one variable. We placed our survival results within a framework that assessed each species’ relative vulnerability by integrating survival estimates with reproductive potential and found that the bigeye thresher, dusky, night, and scalloped hammerhead shark exhibited the highest vulnerabilities to bycatch. We suggest that considering ecological and biological traits of species shows promise for designing effective conservation measures, whereas techniques that reduce fisheries interactions in the first place may be the best strategy for highly vulnerable species.

[New settlers comb jellies Mnemiopsis leidyi (A. Agassiz) and Beroe ovata Mayer 1912 and their influence on the pelagic ecosystem of the northeastern part of the Black Sea].

Science.gov (United States)

Shiganova, T A; Musaeva, E I; Bulgakova, Iu V; Mirzoian, Z A; MartynIuk, M L

2003-01-01

We analyzed the condition of pelagic ecosystem of northeastern Black Sea influenced by expansion of a new settler Beroe ovata in 1999-2001. Expansion of B. ovata considerably decreased the population of another new settler Mnemiopsis leidyi that deformed the Black Sea ecosystem for over a decade. Reduction of M. leidyi population limited its influence on the ecosystem and, consequently, we observed reestablishment of the main components of the Black Sea pelagic ecosystem--zooplankton and fish, their spawn and larvae. The relationship between annual and seasonal variability of the population and biomass of the both new settlers M. leidyi and B. ovata are discussed.

Radioactivity in the pelagic fish. I. Distribution of radioactivity in various tissues of fish

Energy Technology Data Exchange (ETDEWEB)

Amano, K; Yamada, K; Bito, M; Takase, A; Tanaka, S

1955-01-01

Pelagic fishes caught after an atomic explosion experiment at Bikini Atolls in the Pacific were examined by radiochemical techniques. Generally the radioactivity was large in liver, kidney, gall bladder and heart, and then in pyloric ceca, stomach, intestine, and gonad; there was little activity in skin, bone, and muscles. This order varied with species. Large radioactivity of the stomach contents did not necessarily mean large activity in the tissues, indicating considerable participation of diffusion of sea water into the fish body. Muscles from various sites showed slight difference in the activity. The dark muscle, however, showed several times as large activity as ordinary muscle.

Tracking the India-Arabia Transform Plate Boundary during Paleogene Times.

Science.gov (United States)

Rodriguez, M.; Huchon, P.; Chamot-Rooke, N. R. A.; Fournier, M.; Delescluse, M.

2014-12-01

The Zagros and Himalaya mountain belts are the most prominent reliefs built by continental collision. They respectively result from Arabia and India collision with Eurasia. Convergence motions at mountain belts induced most of plate reorganization events in the Indian Ocean during the Cenozoic. Although critical for paleogeographic reconstructions, the way relative motion between Arabia and India was accommodated prior to the formation of the Sheba ridge in the Gulf of Aden remains poorly understood. The India-Arabia plate-boundary belongs to the category of long-lived (~90-Ma) oceanic transform faults, thus providing a good case study to investigate the role of major kinematic events over the structural evolution of a long-lived transform system. A seismic dataset crossing the Owen Fracture Zone, the Owen Basin, and the Oman Margin was acquired to track the past locations of the India-Arabia plate boundary. We highlight the composite age of the Owen Basin basement, made of Paleocene oceanic crust drilled on its eastern part, and composed of pre-Maastrichtian continental crust overlaid by Early Paleocene ophiolites on its western side. A major transform fault system crossing the Owen Basin juxtaposed these two slivers of lithosphere of different ages, and controlled the uplift of marginal ridges along the Oman Margin. This transform system deactivated ~40 Ma ago, coeval with the onset of ultra-slow spreading at the Carlsberg Ridge. The transform boundary then jumped to the edge of the present-day Owen Ridge during the Late Eocene-Oligocene period, before seafloor spreading began at the Sheba Ridge. This migration of the plate boundary involved the transfer of a part of the Indian oceanic lithosphere accreted at the Carlsberg Ridge to the Arabian plate. The episode of plate transfer at the India-Arabia plate boundary during the Late Eocene-Oligocene interval is synchronous with a global plate reorganization event corresponding to geological events at the Zagros and

Geochemistry of groundwater in the eastern Snake River Plain aquifer, Idaho National Laboratory and vicinity, eastern Idaho

Science.gov (United States)

Rattray, Gordon W.

2018-05-30

Nuclear research activities at the U.S. Department of Energy (DOE) Idaho National Laboratory (INL) in eastern Idaho produced radiochemical and chemical wastes that were discharged to the subsurface, resulting in detectable concentrations of some waste constituents in the eastern Snake River Plain (ESRP) aquifer. These waste constituents may pose risks to the water quality of the aquifer. In order to understand these risks to water quality the U.S. Geological Survey, in cooperation with the DOE, conducted a study of groundwater geochemistry to improve the understanding of hydrologic and chemical processes in the ESRP aquifer at and near the INL and to understand how these processes affect waste constituents in the aquifer.Geochemistry data were used to identify sources of recharge, mixing of water, and directions of groundwater flow in the ESRP aquifer at the INL. The geochemistry data were analyzed from 167 sample sites at and near the INL. The sites included 150 groundwater, 13 surface-water, and 4 geothermal-water sites. The data were collected between 1952 and 2012, although most data collected at the INL were collected from 1989 to 1996. Water samples were analyzed for all or most of the following: field parameters, dissolved gases, major ions, dissolved metals, isotope ratios, and environmental tracers.Sources of recharge identified at the INL were regional groundwater, groundwater from the Little Lost River (LLR) and Birch Creek (BC) valleys, groundwater from the Lost River Range, geothermal water, and surface water from the Big Lost River (BLR), LLR, and BC. Recharge from the BLR that may have occurred during the last glacial epoch, or paleorecharge, may be present at several wells in the southwestern part of the INL. Mixing of water at the INL primarily included mixing of surface water with groundwater from the tributary valleys and mixing of geothermal water with regional groundwater. Additionally, a zone of mixing between tributary valley water and

From the epipelagic zone to the abyss: Trophic structure at two seamounts in the subtropical and tropical Eastern Atlantic - Part I zooplankton and micronekton

Science.gov (United States)

Denda, Anneke; Stefanowitsch, Benjamin; Christiansen, Bernd

2017-12-01

Specific mechanisms, driving trophic interactions within the pelagic community may be highly variable in different seamount systems. This study investigated the trophic structure of zooplankton and micronekton above and around Ampère and Senghor, two shallow seamounts in the subtropical and tropical Eastern Atlantic, and over the adjacent abyssal plains. For the identification of food sources and trophic positions stable isotope ratios (δ13C and δ15N) were used. δ13C ranged from -24.7‰ to -15.0‰ and δ15N covered a total range of 0.9-15.9‰. Based on epipelagic particulate organic matter, zooplankton and micronekton usually occupied the 1st-3rd trophic level, including herbivorous, omnivorous and carnivorous taxa. δ13C and δ15N values were generally lower in zooplankton and micronekton of the subtropical waters as compared to the tropical region, due to the differing nutrient availability and phytoplankton communities. Correlations between δ13C and δ15N values of particulate organic matter, zooplankton, micronekton and benthopelagic fishes suggest a linear food chain based on a single energy source from primary production for Ampère Seamount, but no evidence was found for an autochthonus seamount production as compared to the open ocean reference site. Between Senghor Seamount and the open ocean δ13C signatures indicate that hydrodynamic effects at seamounts may modify the energy supply at times, but evidence for a seamount effect on the trophic structure of the pelagic communities was weak, which supports the assumption that seamount communities rely to a large extent on advected food sources.

Characterization of the putatively introduced red alga Acrochaetium secundatum (Acrochaetiales, Rhodophyta) growing epizoically on the pelage of southern sea otters (Enhydra lutris nereis)

Science.gov (United States)

Bentall, Gena B.; Rosen, Barry H.; Kunz, Jessica M.; Miller, Melissa A.; Saunders, Gary W.; LaRoche, Nicole L.

2016-01-01

Ecological associations between epibionts (organisms that live on the surface of another living organism) and vertebrates have been documented in both marine and terrestrial environments, and may be opportunistic, commensal, or symbiotic (Lewin et al. 1981, Holmes 1985, Allen et al. 1993, Bledsoe et al. 2006, Pfaller et al. 2008, Suutari et al. 2010). Although epibiont proliferation is frequently reported on slow-moving, sparsely haired organisms such as manatees and sloths, reports from densely furred, highly mobile mammals are much less common. There are reports of epizoic algae for several species of pinnipeds (Kenyon and Rice 1959, Scheffer 1962, Baldridge 1977, Allen et al. 1993), which rely to varying degrees on both pelage and blubber for thermoregulation, but the phenomenon has not been widely described. Scheffer (1962) noted that red algae was fairly common on the pelage of northern fur seals (Callorhinus ursinus), pinnipeds for which fur likely makes a comparatively high contribution to thermoregulation (Donohue et al. 2000). For species with pelage that plays a critical role of thermal insulation, it seems implausible that an epibiont would persist on healthy individuals that devote significant energy resources toward grooming and actively maintaining their coat. Biological characteristics of epibiont settlement and attachment, and physiological requirements of epizoic species play key roles in their successful colonization and potential host impacts. To investigate this relationship, we explore a novel discovery of an epizoic alga from southern sea otters, including describing algal development on sea otter hair and molecular identification of the algae.

Tektite-bearing, deep-water clastic unit at the Cretaceous-Tertiary boundary in northeastern Mexico

Science.gov (United States)

Smit, J.; Montanari, A.; Swinburne, N. H.; Alvarez, W.; Hildebrand, A. R.; Margolis, S. V.; Claeys, P.; Lowrie, W.; Asaro, F.

1992-01-01

The hypothesis of Cretaceous-Tertiary (K-T) boundary impact on Yucatan, Mexico, predicts that nearby sites should show evidence of proximal impact ejecta and disturbance by giant waves. An outcrop along the Arroyo el Mimbral in northeastern Mexico contains a layered clastic unit up to 3 m thick that interrupts a biostratigraphically complete pelagic-marl sequence deposited at more than 400 m water depth. The marls were found to be unsuitable for determining magnetostratigraphy, but foraminiferal biostratigraphy places the clastic unit precisely at the K-T boundary. We interpret this clastic unit as the deposit of a megawave or tsunami produced by an extraterrestrial impact. The clastic unit comprises three main subunits. (1) The basal "spherule bed" contains glass in the form of tektites and microtektites, glass spherules replaced by chlorite-smectite and calcite, and quartz grains showing probable shock features. This bed is interpreted as a channelized deposit of proximal ejecta. (2) A set of lenticular, massive, graded "laminated beds" contains intraclasts and abundant plant debris, and may be the result of megawave backwash that carried coarse debris from shallow parts of the continental margin into deeper water. (3) At the top, several thin "ripple beds" composed of fine sand are separated by clay drapes; they are interpreted as deposits of oscillating currents, perhaps a seiche. An iridium anomaly (921 +/- 23 pg/g) is observed at the top of the ripple beds. Our observations at the Mimbral locality support the hypothesis of a K-T impact on nearby Yucatan.

Slovenian-Croatian boundary: backgrounds of boundary-making and boundary-breaking in Istria regarding the contemporary boundary dispute

Directory of Open Access Journals (Sweden)

Damir Josipovič

2012-06-01

Full Text Available Boundary-making in Istria is an old undertaking. It has actually never ceasesed, not even today. Istrian peninsula has thus undergone substantial boundary shifts during the last couple of centuries (especially after the Venetian demise in 1797. But Istria carries its worldwide fame also due to one of probably the harshest disputes on the post-war European grounds – the Trieste territory dispute. In author's perspective, this dispute is one of the four main corner-stones of the current Slovenian-Croatian boundary dispute. The remaining three include the Kozler's boundary around Dragonja (Rokava River, the ungraspable notions of Austrian censuses in Istria, and the narratives of partisan settlements on military jurisdiction. However, there are other very important aspects which significantly shaped the development of the dispute, but we will focus at assessing the importance of the aforementioned ones. In this sense, the analysis of the effects of the outcome of the Trieste dispute and its implications to the contemporary interstate dispute is set forth. By unveiling its material and consequently its psychological effects upon the contemporary bilateral relations, its analyses simultaneously reveals backgrounds of never answered question, why Kozler's proposed linguistic boundary around Dragonja (Rokava River turned out to become a boundary of national character. Though nowadays disputed, there is absolutely no chance for both involved parties to substantially draw away from once decisively drawn line of a layman. Despite the fierce battle of words in Slovenian public media on whether should the interstate boundary be placed on Mirna (Quieto or Dragonja Rivers, it will be argued here that the actual choice of the Valley of Dragonja as a boundary is by all means Slovenian. The arguments are based on extensive analyses of cartographic materials, relevant literature, documents, and statistical data.

Slovenian-Croatian boundary: backgrounds of boundary-making and boundary-breaking in Istria regarding the contemporary boundary dispute

Directory of Open Access Journals (Sweden)

Damir Josipovič

2012-01-01

Full Text Available Boundary-making in Istria is an old undertaking. It has actually never ceasesed, not even today. Istrian peninsula has thus undergone substantial boundary shifts during the last couple of centuries (especially after the Venetian demise in 1797. But Istria carries its worldwide fame also due to one of probably the harshest disputes on the post-war European grounds – the Trieste territory dispute. In author's perspective, this dispute is one of the four main corner-stones of the current Slovenian-Croatian boundary dispute. The remaining three include the Kozler's boundary around Dragonja (Rokava River, the ungraspable notions of Austrian censuses in Istria, and the narratives of partisan settlements on military jurisdiction. However, there are other very important aspects which significantly shaped the development of the dispute, but we will focus at assessing the importance of the aforementioned ones. In this sense, the analysis of the effects of the outcome of the Trieste dispute and its implications to the contemporary interstate dispute is set forth. By unveiling its material and consequently its psychological effects upon the contemporary bilateral relations, its analyses simultaneously reveals backgrounds of never answered question, why Kozler's proposed linguistic boundary around Dragonja (Rokava River turned out to become a boundary of national character. Though nowadays disputed, there is absolutely no chance for both involved parties to substantially draw away from once decisively drawn line of a layman. Despite the fierce battle of words in Slovenian public media on whether should the interstate boundary be placed on Mirna (Quieto or Dragonja Rivers, it will be argued here that the actual choice of the Valley of Dragonja as a boundary is by all means Slovenian. The arguments are based on extensive analyses of cartographic materials, relevant literature, documents, and statistical data.

K/Ar dating of the Eastern Rhodope Paleogene magmatism

Energy Technology Data Exchange (ETDEWEB)

Lilov, P.; Yanev, Y.; Marchev, P.

1987-12-01

Paleogene magmatic rocks from the Eastern Rhodope Mountains have seldom been an object of radiogeochronological studies and very few data are available from the geological literature. Until now their dating relied heavily on paleontological data from fossil-bearing sediments, alternating with the lava flows. However, there are also many cross bodies (extrusions, dikes and intrusions) as well as volcanic areas of no sediments or of fossil-free sediments which require the combined use of both methods. This paper aims at characterizing geochronologically the Eastern Rhodope Paleogene volcanism. The K/Ar method was used to date reference volcanoes (mostly with well-defined positions in the Paleogene sequence) associated with the various phases of volcanic activity, as well as some separate intrusive bodies. Nomenclature of volcanics followed the classification of the Soviet Petrographic Commission and that of Peccerillo and Taylor as supplemented by Marchey. The paper characterizes only two of the three main volcanic districts, the Momcilgrad-Arda and the Borovica districts. The third one, Susica district, has restricted exposures near the state boundary between Bulgari and Greece and was excluded from the study. The results obtained are compared with the geochronological scales proposed by Odin and Cavelier and Pomerol which correlate radiogeochronological and paleontological data (nannoplancton data included).

Diet and stable isotope analyses reveal the feeding ecology of the orangeback squid Sthenoteuthis pteropus (Steenstrup 1855 (Mollusca, Ommastrephidae in the eastern tropical Atlantic.

Directory of Open Access Journals (Sweden)

Véronique Merten

Full Text Available In the eastern tropical Atlantic, the orangeback flying squid Sthenoteuthis pteropus (Steenstrup 1855 (Cephalopoda, Ommastrephidae is a dominant species of the epipelagic nekton community. This carnivore squid has a short lifespan and is one of the fastest-growing squids. In this study, we characterise the role of S. pteropus in the pelagic food web of the eastern tropical Atlantic by investigating its diet and the dynamics of its feeding habits throughout its ontogeny and migration. During three expeditions in the eastern tropical Atlantic in 2015, 129 specimens were caught by hand jigging. Stomach content analyses (via visual identification and DNA barcoding were combined with stable isotope data (∂15N and ∂13C of muscle tissue to describe diet, feeding habits and trophic ecology of S. pteropus. Additionally, stable isotope analyses of incremental samples along the squid's gladius-the chitinous spiniform structure supporting the muscles and organs-were carried out to explore possible diet shifts through ontogeny and migration. Our results show that S. pteropus preys mainly on myctophid fishes (e.g. Myctophum asperum, Myctophum nitidulum, Vinciguerria spp., but also on other teleost species, cephalopods (e.g. Enoploteuthidae, Bolitinidae, Ommastrephidae, crustaceans and possibly on gelatinous zooplankton as well. The squid shows a highly opportunistic feeding behaviour that includes cannibalism. Our study indicates that the trophic position of S. pteropus may increase by approximately one trophic level from a mantle length of 15 cm to 47 cm. The reconstructed isotope-based feeding chronologies of the gladii revealed high intra- and inter-individual variability in the squid's trophic position and foraging area. These findings are not revealed by diet or muscle tissue stable isotope analysis. This suggests a variable and complex life history involving individual variation and migration. The role of S. pteropus in transferring energy and

Diet and stable isotope analyses reveal the feeding ecology of the orangeback squid Sthenoteuthis pteropus (Steenstrup 1855) (Mollusca, Ommastrephidae) in the eastern tropical Atlantic.

Science.gov (United States)

Merten, Véronique; Christiansen, Bernd; Javidpour, Jamileh; Piatkowski, Uwe; Puebla, Oscar; Gasca, Rebeca; Hoving, Henk-Jan T

2017-01-01

In the eastern tropical Atlantic, the orangeback flying squid Sthenoteuthis pteropus (Steenstrup 1855) (Cephalopoda, Ommastrephidae) is a dominant species of the epipelagic nekton community. This carnivore squid has a short lifespan and is one of the fastest-growing squids. In this study, we characterise the role of S. pteropus in the pelagic food web of the eastern tropical Atlantic by investigating its diet and the dynamics of its feeding habits throughout its ontogeny and migration. During three expeditions in the eastern tropical Atlantic in 2015, 129 specimens were caught by hand jigging. Stomach content analyses (via visual identification and DNA barcoding) were combined with stable isotope data (∂15N and ∂13C) of muscle tissue to describe diet, feeding habits and trophic ecology of S. pteropus. Additionally, stable isotope analyses of incremental samples along the squid's gladius-the chitinous spiniform structure supporting the muscles and organs-were carried out to explore possible diet shifts through ontogeny and migration. Our results show that S. pteropus preys mainly on myctophid fishes (e.g. Myctophum asperum, Myctophum nitidulum, Vinciguerria spp.), but also on other teleost species, cephalopods (e.g. Enoploteuthidae, Bolitinidae, Ommastrephidae), crustaceans and possibly on gelatinous zooplankton as well. The squid shows a highly opportunistic feeding behaviour that includes cannibalism. Our study indicates that the trophic position of S. pteropus may increase by approximately one trophic level from a mantle length of 15 cm to 47 cm. The reconstructed isotope-based feeding chronologies of the gladii revealed high intra- and inter-individual variability in the squid's trophic position and foraging area. These findings are not revealed by diet or muscle tissue stable isotope analysis. This suggests a variable and complex life history involving individual variation and migration. The role of S. pteropus in transferring energy and nutrients from

Effects of nitrate and phosphate supply on chromophoric and fluorescent dissolved organic matter in the Eastern Tropical North Atlantic: a mesocosm study

Science.gov (United States)

Loginova, A. N.; Borchard, C.; Meyer, J.; Hauss, H.; Kiko, R.; Engel, A.

2015-12-01

In open-ocean regions, as is the Eastern Tropical North Atlantic (ETNA), pelagic production is the main source of dissolved organic matter (DOM) and is affected by dissolved inorganic nitrogen (DIN) and phosphorus (DIP) concentrations. Changes in pelagic production under nutrient amendments were shown to also modify DOM quantity and quality. However, little information is available about the effects of nutrient variability on chromophoric (CDOM) and fluorescent (FDOM) DOM dynamics. Here we present results from two mesocosm experiments ("Varied P" and "Varied N") conducted with a natural plankton community from the ETNA, where the effects of DIP and DIN supply on DOM optical properties were studied. CDOM accumulated proportionally to phytoplankton biomass during the experiments. Spectral slope (S) decreased over time indicating accumulation of high molecular weight DOM. In Varied N, an additional CDOM portion, as a result of bacterial DOM reworking, was determined. It increased the CDOM fraction in DOC proportionally to the supplied DIN. The humic-like FDOM component (Comp.1) was produced by bacteria proportionally to DIN supply. The protein-like FDOM component (Comp.2) was released irrespectively to phytoplankton or bacterial biomass, but depended on DIP and DIN concentrations. Under high DIN supply, Comp.2 was removed by bacterial reworking, leading to an accumulation of humic-like Comp.1. No influence of nutrient availability on amino acid-like FDOM component in peptide form (Comp.3) was observed. Comp.3 potentially acted as an intermediate product during formation or degradation of Comp.2. Our findings suggest that changes in nutrient concentrations may lead to substantial responses in the quantity and quality of optically active DOM and, therefore, might bias results of the applied in situ optical techniques for an estimation of DOC concentrations in open-ocean regions.

Impacts of interannual variation of the East Asian winter monsoon on aerosol concentrations over eastern China

Science.gov (United States)

Zhu, J.; Liao, H.; Li, J.; Feng, J.

2012-04-01

China has been experiencing increased concentrations of aerosols, commonly attributed to the large increases in emissions associated with the rapid economic development. We apply a global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) driven by the NASA/GEOS-4 assimilated meteorological data to quantify the impacts of East Asian winter monsoon (EAWM) on the aerosol concentrations over eastern China. We found that the simulated aerosol concentrations over eastern China have strong interannual variation and negative correlations with the strength of EAWM. Model results show that, accounting for sulfate, nitrate, ammonium, black carbon, and organic carbon aerosols, the winter surface layer PM2.5 concentration averaged over eastern China (110°-125°E, 20°-45°N) can be 17.97% (4.78 µg m-3) higher in the weak monsoon years than that in the strong monsoon years. Regionally, the weakening of EAWM is shown to be able to increase PM2.5 concentration in the middle and lower reach of the Yellow River by 12 µg m-3. This point indicates that climate change associated with variation of EAWM has an essential influence on worsening air quality over eastern China. The possible causes of higher aerosol concentrations in the weak monsoon years may be attributed to the changing in wind fields and planetary boundary layer height between the weak and strong monsoon years. Sensitivity studies are performed to identify the role of chemical reaction associated with temperature and humidity on the higher aerosol concentrations in the weak monsoon years over eastern China.

Production of juvenile and sub-adult cobia in recirculating aquaculture systems

Science.gov (United States)

Cobia Rachycentron canadum is a large migratory pelagic finfish species that is distributed worldwide in tropical, subtropical, and warm temperate seas except the Mediterranean and the central and eastern Pacific. Despite its large size, commonly exceeding 23 kg at maturity, and excellent food qual...

Technology for Boundaries

DEFF Research Database (Denmark)

Bødker, Susanne; Kristensen, Jannie Friis; Nielsen, Christina

2003-01-01

.After analysing the history and the current boundary work, the paper will propose new technological support for boundary work. In particular the paper will suggest means of supporting boundaries when these are productive and for changing boundaries when this seems more appropriate. In total, flexible technologies......This paper presents a study of an organisation, which is undergoing a process transforming organisational and technological boundaries. In particular, we shall look at three kinds of boundaries: the work to maintain and change the boundary between the organisation and its customers; boundaries...... seem a core issue when dealing with technology for boundaries....

Does predation control adult sex ratios and longevities in marine pelagic copepods?

DEFF Research Database (Denmark)

Hirst, A.G.; Bonnet, D.; Conway, D.V.P.

2010-01-01

We assess the causes of adult sex ratio skew in marine pelagic copepods by examining changes in these ratios between the juveniles and adults, sexual differences in juvenile stage durations, and mortality rates of adults in the field and laboratory (when free from predators). In the field, late...... copepodite stages (CIV and CV) commonly have sex ratios that are either not significantly different from equity (1 : 1), or slightly male biased. By contrast, in adults, these ratios are commonly significantly biased toward female dominance. Sex ratio skews are therefore primarily attributable to processes...... in adults. Members of the non-Diaptomoidea have especially skewed adult ratios; in the members Oithonidae and Clausocalanidae this is not generated from differences between male and female adult physiological longevity (i.e., laboratory longevity when free of predators). In the genera Acartia, Oithona...

Projected shifts in copepod surface communities in the Mediterranean Sea under several climate change scenarios

Science.gov (United States)

Benedetti, F.; Guilhaumon, F.; Adloff, F.; Irisson, J. O.; Ayata, S. D.

2016-02-01

Although future increases in water temperature and future changes in regional circulation are expected to have great impacts on the pelagic food-web, estimates focusing on community-level shifts are still lacking for the planktonic compartment. By combining statistical niche models (or species distribution models) with projections from a regional circulation model, the impact of climate change on copepod epipelagic communities is assessed for the Mediterranean Sea. Habitat suitability maps are generated for 106 of the most abundant copepod species to analyze emerging patterns of diversity at the community level. Using variance analysis, we also quantified the uncertainties associated to our modeling strategy (niche model choice, CO2 emission scenario, boundary forcings of the circulation model). Comparing present and future projections, changes in species richness (alpha diversity) and in community composition (beta diversity, decomposed into turnover and nestedness component) are calculated. Average projections show that copepod communities will mainly experience turn-over processes, with little changes in species richness. Species gains are mainly located in the Gulf of Lions, the Northern Adriatic and the Northern Aegean seas. However, projections are highly variable, especially in the Eastern Mediterranean basin. We show that such variability is mainly driven by the choice of the niche model, through interactions with the CO2 emission scenario or the boundary forcing of the circulation model can be locally important. Finally, the possible impact of the estimated community changes on zooplanktonic functional and phylogenetic diversity is also assessed. We encourage the enlargement of this type of study to other components of the pelagic food-web, and argue that niche models' outputs should always be given along with a measure of uncertainty, and explained in light of a strong theoretical background.

Interelement relationship in abyssal Pacific ferromanganese nodules and associated pelagic sediments

Energy Technology Data Exchange (ETDEWEB)

Li, Y H

1982-01-01

By R-mode factor analysis and enrichment factor calculations, most of the elements in abyssal ferromanganese nodules and associated pelagic sediments (excluding common authigenic minerals like apatite, barite, opal and carbonates) are found to be preferentially concentrated in one of the following three major phases: aluminosilicates (e.g., Al, Si, Sc, Ga, Cr, Be, Na, K, Rb and Cs), Fe-oxides (e.g., Fe, P, S, V, Se, Te, As, B, Sn, U, Hg, Pb, Ti, Ge, Y, Zr, Nb, Pd, In, rare-earths, Hf, Th, Pa, Pu, Am, Ru and Bi), and Mn-oxides (e.g., Mn, Tl, Ag, Cd, Mg, Ca, Ba, Ra, Co, Ni, Cu, Zn, Mo, Sb and probably W). The specific association of elements with these three phases can be explained by the difference in chemical forms of elements in seawater and by fundamental differences in physicochemical properties (e.g., the pH of zero point of charge and dielectric constant) of these three phases.

Interelement relationship in abyssal Pacific ferromanganese nodules and associated pelagic sediments

Energy Technology Data Exchange (ETDEWEB)

Li, Y -H

1982-06-01

By R-mode factor analysis and enrichment factor calculations, most of the elements in abyssal ferromanganese nodules and associated pelagic sediments (excluding common authigenic minerals like apatite, barite, opal and carbonates) are found to be preferentially concentrated in one of the following three major phases: aluminosilicates (e.g., Al, Si, Sc, Ga, Cr, Be, Na, K, Rb and Cs), Fe-oxides (e.g., Fe, P, S, V, Se, Te, As, B, Sn, U, Hg, Pb, Ti, Ge, Y, Zr, Nb, Pd, In, rare-earths, Hf, Th, Pa, Pu, Am, Ru and Bi), and Mn-oxides (e.g., Mn, Tl, Ag, Cd, Mg, Ca, Ba, Ra, Co, Ni, Cu, Zn, Mo, Sb and probably W). The specific association of elements with these three phases can be explained by the difference in chemical forms of elements in seawater and by fundamental differences in physiocochemical properties (e.g., the pH of zero point of charge and dieletric constant) of these three phases.

Model-based estimation with boundary side information or boundary regularization

International Nuclear Information System (INIS)

Chiao, P.C.; Rogers, W.L.; Fessler, J.A.; Clinthorne, N.H.; Hero, A.O.

1994-01-01

The authors have previously developed a model-based strategy for joint estimation of myocardial perfusion and boundaries using ECT (Emission Computed Tomography). The authors have also reported difficulties with boundary estimation in low contrast and low count rate situations. In this paper, the authors propose using boundary side information (obtainable from high resolution MRI and CT images) or boundary regularization to improve both perfusion and boundary estimation in these situations. To fuse boundary side information into the emission measurements, the authors formulate a joint log-likelihood function to include auxiliary boundary measurements as well as ECT projection measurements. In addition, the authors introduce registration parameters to align auxiliary boundary measurements with ECT measurements and jointly estimate these parameters with other parameters of interest from the composite measurements. In simulated PET O-15 water myocardial perfusion studies using a simplified model, the authors show that the joint estimation improves perfusion estimation performance and gives boundary alignment accuracy of <0.5 mm even at 0.2 million counts. The authors implement boundary regularization through formulating a penalized log-likelihood function. The authors also demonstrate in simulations that simultaneous regularization of the epicardial boundary and myocardial thickness gives comparable perfusion estimation accuracy with the use of boundary side information

Short-term alteration of biotic and abiotic components of the pelagic system in a shallow bay produced by a strong natural hypoxia event

Science.gov (United States)

Veas, Rodrigo; Anabalón, Valeria; Quiñones, Renato A.

2017-01-01

In January 2008 there was an intensive and extensive upwelling event in the southern Humboldt Current System. This event produced an intrusion of water with low dissolved oxygen into Coliumo Bay, which caused massive mortality and the beaching of pelagic and benthic organisms, including zooplankton. During this event, which lasted 3 to 5 days, we studied and evaluated the effect of the hypoxic water in the bay on the abundance of macrozooplankton, nanoplankton and microphytoplankton, the concentration of several nutrients and hydrographic conditions. At the beginning of the hypoxia event the water column had very low dissolved oxygen concentrations (oxygen minimum zone from the Humboldt Current System. Redox, pH, nitrate, phosphate, silicate and chlorophyll-a values were the lowest, while nitrate and the phaeopigment values were the highest. The N:P ratio was below 16, and the abundance of nano- and microphytoplankton were at their lowest, the latter also with the lowest proportion of live organisms. Macrozooplankton had the greatest abundance during hypoxia, dominated mainly by crustacean, fish eggs and amphipods. The hypoxia event generated a strong short-term alteration of all biotic and abiotic components of the pelagic system in Coliumo Bay and the neighboring coastal zone. These negative effects associated with strong natural hypoxia events could have important consequences for the productivity and ecosystem functioning of the coastal zone of the Humboldt Current System if, as suggested by several models, winds favorable to upwelling should increase due to climate change. The effects of natural hypoxia in this coastal zone can be dramatic especially for pelagic and benthic species not adapted to endure conditions of low dissolved oxygen. PMID:28715447

Benthic and pelagic pathways of methylmercury bioaccumulation in estuarine food webs of the northeast United States.

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Celia Y Chen

Full Text Available Methylmercury (MeHg is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine. MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides. Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column.

From boundaries to boundary work: middle managers creating inter-organizational change.

Science.gov (United States)

Oldenhof, Lieke; Stoopendaal, Annemiek; Putters, Kim

2016-11-21

Purpose In healthcare, organizational boundaries are often viewed as barriers to change. The purpose of this paper is to show how middle managers create inter-organizational change by doing boundary work: the dual act of redrawing boundaries and coordinating work in new ways. Design/methodology/approach Theoretically, the paper draws on the concept of boundary work from Science and Technology Studies. Empirically, the paper is based on an ethnographic investigation of middle managers that participate in a Dutch reform program across health, social care, and housing. Findings The findings show how middle managers create a sense of urgency for inter-organizational change by emphasizing "fragmented" service provision due to professional, sectoral, financial, and geographical boundaries. Rather than eradicating these boundaries, middle managers change the status quo gradually by redrawing composite boundaries. They use boundary objects and a boundary-transcending vocabulary emphasizing the need for societal gains that go beyond production targets of individual organizations. As a result, work is coordinated in new ways in neighborhood teams and professional expertise is being reconfigured. Research limitations/implications Since boundary workers create incremental change, it is necessary to follow their work for a longer period to assess whether boundary work contributes to paradigm change. Practical implications Organizations should pay attention to conditions for boundary work, such as legitimacy of boundary workers and the availability of boundary spaces that function as communities of practice. Originality/value By shifting the focus from boundaries to boundary work, this paper gives valuable insights into "how" boundaries are redrawn and embodied in objects and language.

Basin-scale estimates of pelagic and coral reef calcification in the Red Sea and Western Indian Ocean.

Science.gov (United States)

Steiner, Zvi; Erez, Jonathan; Shemesh, Aldo; Yam, Ruth; Katz, Amitai; Lazar, Boaz

2014-11-18

Basin-scale calcification rates are highly important in assessments of the global oceanic carbon cycle. Traditionally, such estimates were based on rates of sedimentation measured with sediment traps or in deep sea cores. Here we estimated CaCO3 precipitation rates in the surface water of the Red Sea from total alkalinity depletion along their axial flow using the water flux in the straits of Bab el Mandeb. The relative contribution of coral reefs and open sea plankton were calculated by fitting a Rayleigh distillation model to the increase in the strontium to calcium ratio. We estimate the net amount of CaCO3 precipitated in the Red Sea to be 7.3 ± 0.4·10(10) kg·y(-1) of which 80 ± 5% is by pelagic calcareous plankton and 20 ± 5% is by the flourishing coastal coral reefs. This estimate for pelagic calcification rate is up to 40% higher than published sedimentary CaCO3 accumulation rates for the region. The calcification rate of the Gulf of Aden was estimated by the Rayleigh model to be ∼1/2 of the Red Sea, and in the northwestern Indian Ocean, it was smaller than our detection limit. The results of this study suggest that variations of major ions on a basin scale may potentially help in assessing long-term effects of ocean acidification on carbonate deposition by marine organisms.

Evidence of Boundary Reflection of Kelvin and First-Mode Rossby Waves from Topex/Poseidon Sea Level Data

Science.gov (United States)

Boulanger, Jean-Philippe; Fu, Lee-Lueng

1996-01-01

The TOPEX/POSEIDON sea level data lead to new opportunities to investigate some theoretical mechanisms suggested to be involved in the El Nino-Southern Oscillation phenomenon in the tropical Pacific ocean. In particular, we are interested in studying the western boundary reflection, a process crucial for the delayed action oscillator theory, by using the TOPEX/POSEIDON data from November 1992 to May 1995. We first projected the sea level data onto Kelvin and first-mode Ross waves. Then we estimated the contribution of wind forcing to these waves by using a single baroclinic mode simple wave model forced by the ERS-1 wind data. Wave propagation was clearly observed with amplitudes well explained by the wind forcing in the ocean interior. Evidence of wave reflection was detected at both the western and eastern boundaries of the tropical Pacific ocean. At the eastern boundary, Kelvin waves were seen to reflect as first-mode Rossby waves during the entire period. The reflection efficiency (in terms of wave amplitude) of the South American coasts was estimated to be 80% of that of an infinite meridional wall. At the western boundary, reflection was observed in April-August 1993, in January-June 1994, and, later, in December 1994 to February 1995. Although the general roles of these reflection events in the variability observed in the equatorial Pacific ocean are not clear, the data suggest that the reflections in January-June 1994 have played a role in the onset of the warm conditions observed in late 1994 to early 1995. Indeed, during the January-June 1994 period, as strong downwelling first-mode Rossby waves reflected into downwelling Kelvin waves, easterly wind and cold sea surface temperature anomalies located near the date line weakened and eventually reversed in June-July 1994. The presence of the warm anomalies near the date line then favored convection and westerly wind anomalies that triggered strong downwelling Kelvin waves propagating throughout the basin

Tectonic geomorphology and volcano-tectonic interaction in the eastern boundary of the Southern Cascades (Hat Creek Graben region, California, USA

Directory of Open Access Journals (Sweden)

Engielle Mae Raot-raot Paguican

2016-07-01

Full Text Available The eastern boundary of the Southern Cascades (Hat Creek Graben region, California, USA, is an extensively faulted volcanic corridor between the Cascade Range and Modoc Plateau. The east-west extending region is in the transition zone between the convergence and subduction of the Gorda Plate underneath the North American Plate; north-south shortening within the Klamath Mountain region; and transcurrent movement in the Walker Lane. We describe the geomorphological and tectonic features, their alignment and distribution, in order to understand the tectonic geomorphology and volcano-tectonic relationships. One outcome of the work is a more refined morpho-structural description that will affect future hazard assessment in the area.A database of volcanic centers and structures was created from interpretations of topographic models generated from satellite images. Volcanic centers in the region were classified by morphological type into cones, sub-cones, shields and massifs. A second classification by height separated the bigger and smaller edifices and revealed an evolutionary trend. Poisson Nearest Neighbor analysis shows that bigger volcanoes are spatially dispersed while smaller ones are clustered. Using volcano centroid locations, about 90 lineaments consisting of at least three centers within 6km of one another were found, revealing that preferential north-northwest directed pathways control the transport of magma from the source to the surface, consistent with the strikes of the major fault systems. Most of the volcano crater openings are perpendicular to the maximum horizontal stress, expected for extensional environments with dominant normal regional faults. These results imply that the extension of the Hat Creek Graben region and impingement of the Walker Lane is accommodated mostly by extensional faults and partly by the intrusions that formed the volcanoes. Early in the history of a volcano or volcano cluster, melt produced at depth in the

Micromammal biostratigraphy of the Alcoy Basin (Eastern Spain): remarks on the Mio-Pliocene boundary of the Iberian Peninsula

Energy Technology Data Exchange (ETDEWEB)

Mansino, S.; Fierro, I.; Tossal, A.; Montoya, P.; Ruiz-Sánchez, F.J.

2017-11-01

The study of 13 micromammal localities in the southern section of the Gormaget ravine (Alcoi Basin, SE Spain) and another 4 localities in the northern section has allowed us to define four local biozones in the dawn of the Pliocene, possibly recording the Mio-Pliocene boundary. The great density of localities close to the Mio-Pliocene boundary has enabled us to achieve a great resolution in the biozonation of the earliest Pliocene, only comparable in the Iberian Peninsula to the record of the Teruel Basin (NE Spain). We interpret these biozones in the light ofthe Neogene Mammal units and the European Land Mammal Ages, and correlate them with other local biozones defined for the same time span in the Iberian Peninsula.

Micromammal biostratigraphy of the Alcoy Basin (Eastern Spain): remarks on the Mio-Pliocene boundary of the Iberian Peninsula

International Nuclear Information System (INIS)

Mansino, S.; Fierro, I.; Tossal, A.; Montoya, P.; Ruiz-Sánchez, F.J.

2017-01-01

The study of 13 micromammal localities in the southern section of the Gormaget ravine (Alcoi Basin, SE Spain) and another 4 localities in the northern section has allowed us to define four local biozones in the dawn of the Pliocene, possibly recording the Mio-Pliocene boundary. The great density of localities close to the Mio-Pliocene boundary has enabled us to achieve a great resolution in the biozonation of the earliest Pliocene, only comparable in the Iberian Peninsula to the record of the Teruel Basin (NE Spain). We interpret these biozones in the light ofthe Neogene Mammal units and the European Land Mammal Ages, and correlate them with other local biozones defined for the same time span in the Iberian Peninsula.

Boundaries of dreams, boundaries of dreamers: thin and thick boundaries as a new personality measure.

Science.gov (United States)

Hartmann, E

1989-11-01

Previous work by the author and his collaborators on frequent nightmare sufferers demonstrated that these people had striking personality characteristics which could be called "thin boundaries" in a number of different senses. In order to measure thin and thick boundaries, a 145-item questionnaire, the Boundary Questionnaire, has been developed which has now been taken by over 1,000 persons. Preliminary results are presented indicating that, as predicted a priori, several new groups of nightmare sufferers and groups of art students scored usually "thin," whereas a group of naval officers had usually "thick" boundaries. Overall, thinness on the Boundary Questionnaire correlated highly positively (r = .40) with frequency of dream recall and also significantly (r = .16) with length of sleep.

Bioaccumulation of trace elements in pelagic fish from the Western Indian Ocean

International Nuclear Information System (INIS)

Kojadinovic, Jessica; Potier, Michel; Le Corre, Matthieu; Cosson, Richard P.; Bustamante, Paco

2007-01-01

Trace elements were analyzed in fish of commercial interest to determine their importance in marine systems of the Western Indian Ocean and their bioaccumulation patterns. The results are equivalent or lower than levels reported in ichthyofauna worldwide. Certain values of muscular Cd, Hg, Pb and Zn were, however, above thresholds for human consumption. Levels varied among tissues, species and fish length, but were seldom influenced by the nutritional condition of the fish, its gender and its reproductive status. Correlations between hepatic Hg and Se levels in Swordfish (r 2 = 0.747) and Yellowfin Tunas (r 2 = 0.226), and among metallothionein linking metals imply the existence of detoxification processes in these species. Level differences between fish from the Mozambique Channel and Reunion Island reflect differences of diets rather than differences of elemental availability in both environments. - Metal bioaccumulation was quantified in four species of pelagic fish

IAEA/WHO postal dose audits for radiotherapy hospitals in Eastern and South-Eastern Europe

International Nuclear Information System (INIS)

Izewska, J.; Vatnitsky, S.; Shortt, K.R.

2004-01-01

The IAEA/WHO TLD programme has been in operation for 34 years. In this period the calibration of approximately 5200 high-energy photon beams in over 1300 radiotherapy hospitals in 115 countries worldwide was checked. Of these, 18% of the audits were performed in Eastern and South-Eastern Europe. There are large contrasts in the region; while the results are very good for most countries, a few countries struggle with basic problems in dosimetry. The hospitals operating radiotherapy services without qualified medical physicists or dosimetry equipment have poorer results than those properly equipped and staffed. Only about 2/3 of TLD audit participants in Eastern Europe have the appropriate dosimetry equipment. To achieve consistency of the audit results within Eastern and South-Eastern Europe, strengthening of radiotherapy infrastructure in a few countries would be necessary. (authors)

75 FR 68397 - DeQueen and Eastern Railroad, LLC-Acquisition and Operation Exemption-DeQueen and Eastern...

Science.gov (United States)

2010-11-05

... Eastern Railroad, LLC--Acquisition and Operation Exemption--DeQueen and Eastern Railroad Company DeQueen and Eastern Railroad, LLC (DQE), a noncarrier, has filed a verified notice of exemption under 49 CFR 1150.31 to acquire from DeQueen and Eastern Railroad Company and to operate approximately 47 miles of...

Area Studies and Eastern Europe: How Eastern Europe Collapsed

Directory of Open Access Journals (Sweden)

Mirjana Kasapović

2007-01-01

Full Text Available In the first part, the author outlines the development of area studies in contemporary comparative politics, and points to their importance for the development of political science. In the second part, she examines the methodology – research design and methods – of regional comparatistics, paying particular attention to the problem of defining the region as a central category in this field of comparative politics. The third and central part is focused on the emergence of Eastern Europe as a historical-political and socio-cultural region in the course of history, especially after World War II, and on its dissolution in the processes of democratic transformation of communist regimes in the last two decades. The dissolution of Eastern Europe has resulted in restoration of a tripartite political geography in the area which it used to take up, made up of Central Europe, Southeast Europe and the proper Eastern Europe.

Seismotectonics of Bhutan: Evidence for segmentation of the Eastern Himalayas and link to foreland deformation

Science.gov (United States)

Diehl, Tobias; Singer, Julia; Hetényi, György; Grujic, Djordje; Clinton, John; Giardini, Domenico; Kissling, Edi; Gansser Working Group

2017-08-01

The instrumental record of Bhutan is characterized by a lower seismicity compared to other parts of the Himalayan arc. To understand this low activity and its impact on the seismic hazard, a seismic network was installed in Bhutan for 22 months between 2013 and 2014. Recorded seismicity, earthquake moment tensors and local earthquake tomography reveal along-strike variations in structure and crustal deformation regime. A thickened crust imaged in western Bhutan suggests lateral differences in stresses on the Main Himalayan Thrust (MHT), potentially affecting the interseismic coupling and deformation regime. Sikkim, western Bhutan and its foreland are characterized by strike-slip faulting in the Indian basement. Strain is particularly localized along a NW-SE striking mid-crustal fault zone reaching from Chungthang in northeast Sikkim to Dhubri at the northwestern edge of the Shillong Plateau in the foreland. The dextral Dhubri-Chungthang fault zone (DCF) causes segmentation of the Indian basement and the MHT between eastern Nepal and western Bhutan and connects the deformation front of the Himalaya with the Shillong Plateau by forming the western boundary of the Shillong block. The Kopili fault, the proposed eastern boundary of this block, appears to be a diffuse zone of mid-crustal seismicity in the foreland. In eastern Bhutan we image a seismogenic, flat portion of the MHT, which might be either related to a partially creeping segment or to increased background seismicity originating from the 2009 MW 6.1 earthquake. In western-central Bhutan clusters of micro-earthquakes at the front of the High-Himalayas indicate the presence of a mid-crustal ramp and stress buildup on a fully coupled MHT. The area bounded by the DCF in the west and the seismogenic MHT in the east has the potential for M7-8 earthquakes in Bhutan. Similarly, the DCF has the potential to host M7 earthquakes as documented by the 2011 Sikkim and the 1930 Dhubri earthquakes, which were potentially

Evolutionary origin of the Scombridae (tunas and mackerels: members of a paleogene adaptive radiation with 14 other pelagic fish families.

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Masaki Miya

Full Text Available Uncertainties surrounding the evolutionary origin of the epipelagic fish family Scombridae (tunas and mackerels are symptomatic of the difficulties in resolving suprafamilial relationships within Percomorpha, a hyperdiverse teleost radiation that contains approximately 17,000 species placed in 13 ill-defined orders and 269 families. Here we find that scombrids share a common ancestry with 14 families based on (i bioinformatic analyses using partial mitochondrial and nuclear gene sequences from all percomorphs deposited in GenBank (10,733 sequences and (ii subsequent mitogenomic analysis based on 57 species from those targeted 15 families and 67 outgroup taxa. Morphological heterogeneity among these 15 families is so extraordinary that they have been placed in six different perciform suborders. However, members of the 15 families are either coastal or oceanic pelagic in their ecology with diverse modes of life, suggesting that they represent a previously undetected adaptive radiation in the pelagic realm. Time-calibrated phylogenies imply that scombrids originated from a deep-ocean ancestor and began to radiate after the end-Cretaceous when large predatory epipelagic fishes were selective victims of the Cretaceous-Paleogene mass extinction. We name this clade of open-ocean fishes containing Scombridae "Pelagia" in reference to the common habitat preference that links the 15 families.

Methylmercury biomagnification in an Arctic pelagic food web.

Science.gov (United States)

Ruus, Anders; Øverjordet, Ida B; Braaten, Hans Fredrik V; Evenset, Anita; Christensen, Guttorm; Heimstad, Eldbjørg S; Gabrielsen, Geir W; Borgå, Katrine

2015-11-01

Mercury (Hg) is a toxic element that enters the biosphere from natural and anthropogenic sources, and emitted gaseous Hg enters the Arctic from lower latitudes by long-range transport. In aquatic systems, anoxic conditions favor the bacterial transformation of inorganic Hg to methylmercury (MeHg), which has a greater potential for bioaccumulation than inorganic Hg and is the most toxic form of Hg. The main objective of the present study was to quantify the biomagnification of MeHg in a marine pelagic food web, comprising species of zooplankton, fish, and seabirds, from the Kongsfjorden system (Svalbard, Norway), by use of trophic magnification factors. As expected, tissue concentrations of MeHg increased with increasing trophic level in the food web, though at greater rates than observed in several earlier studies, especially at lower latitudes. There was strong correlation between MeHg and total Hg concentrations through the food web as a whole. The concentration of MeHg in kittiwake decreased from May to October, contributing to seasonal differences in trophic magnification factors. The ecology and physiology of the species comprising the food web in question may have a large influence on the magnitude of the biomagnification. A significant linear relationship was also observed between concentrations of selenium and total Hg in birds but not in zooplankton, suggesting the importance of selenium in Hg detoxification for individuals with high Hg concentrations. © 2015 SETAC.

Spatio-temporal patterns and environmental controls of small pelagic fish body condition from contrasted Mediterranean areas

Science.gov (United States)

Brosset, Pablo; Fromentin, Jean-Marc; Van Beveren, Elisabeth; Lloret, Josep; Marques, Virginie; Basilone, Gualtiero; Bonanno, Angelo; Carpi, Piera; Donato, Fortunata; Čikeš Keč, Vanja; De Felice, Andrea; Ferreri, Rosalia; Gašparević, Denis; Giráldez, Ana; Gücü, Ali; Iglesias, Magdalena; Leonori, Iole; Palomera, Isabel; Somarakis, Stylianos; Tičina, Vjekoslav; Torres, Pedro; Ventero, Ana; Zorica, Barbara; Ménard, Frédéric; Saraux, Claire

2017-02-01

Small pelagic fish are among the most ecologically and economically important marine fish species and are characterized by large fluctuations all over the world. In the Mediterranean Sea, low catches and biomass of anchovies and sardines have been described in some areas during the last decade, resulting in important fisheries crises. Therefore, we studied anchovy and sardine body condition variability, a key index of population health and its response to environmental and anthropogenic changes. Wide temporal and spatial patterns were investigated by analyzing separately data from scientific surveys and fisheries in eight Mediterranean areas between 1975 and 2015. Results showed that anchovy and sardine body condition as well as maximum size in some areas sharply decreased in most Mediterranean areas along years (except in the Northern Alboran Sea). Despite this general pattern, well-marked environmental differences between sub-regions were highlighted by several analyses and variations in body condition were not found to be homogeneous over all the Mediterranean Sea. Further, other analyses revealed that except for the Adriatic where major changes towards a lower body condition were concomitant with a decrease in river runoffs and chl-a concentration, no concomitant environmental regime shift was detected in other areas. Together, these analyses highlighted the current poor body condition of almost all small pelagic fish populations in the Mediterranean. Yet, global environmental indices could not explain the observed changes and the general decrease in condition might more likely come from regional environmental and/or anthropogenic (fishing) effects. A prolonged state of poor fish body condition, together with an observed reduced size and early age-at-maturity may have strong ecological, economic and social consequences all around the Mediterranean Sea.

Prototyping global Earth System Models at high resolution: Representation of climate, ecosystems, and acidification in Eastern Boundary Currents

Science.gov (United States)

Dunne, J. P.; John, J. G.; Stock, C. A.

2013-12-01

The world's major Eastern Boundary Currents (EBC) such as the California Current Large Marine Ecosystem (CCLME) are critically important areas for global fisheries. Computational limitations have divided past EBC modeling into two types: high resolution regional approaches that resolve the strong meso-scale structures involved, and coarse global approaches that represent the large scale context for EBCs, but only crudely resolve only the largest scales of their manifestation. These latter global studies have illustrated the complex mechanisms involved in the climate change and acidification response in these regions, with the CCLME response dominated not by local adjustments but large scale reorganization of ocean circulation through remote forcing of water-mass supply pathways. While qualitatively illustrating the limitations of regional high resolution studies in long term projection, these studies lack the ability to robustly quantify change because of the inability of these models to represent the baseline meso-scale structures of EBCs. In the present work, we compare current generation coarse resolution (one degree) and a prototype next generation high resolution (1/10 degree) Earth System Models (ESMs) from NOAA's Geophysical Fluid Dynamics Laboratory in representing the four major EBCs. We review the long-known temperature biases that the coarse models suffer in being unable to represent the timing and intensity of upwelling-favorable winds, along with lack of representation of the observed high chlorophyll and biological productivity resulting from this upwelling. In promising contrast, we show that the high resolution prototype is capable of representing not only the overall meso-scale structure in physical and biogeochemical fields, but also the appropriate offshore extent of temperature anomalies and other EBC characteristics. Results for chlorophyll were mixed; while high resolution chlorophyll in EBCs were strongly enhanced over the coarse resolution

Temporal and Spatial Distribution of Catches of Tiger Sharks, Galeocerdo cuvier, in the Pelagic Longline Fishery Around the Hawaiian Islands

OpenAIRE

Polovina, Jeffrey J.; Lau, Boulderson B.

1993-01-01

Thirty-five tiger sharks, Galeocerdo cuvier, have been reported caught in pelagic longline gearfrom 25 to 265 n.mi. off the Hawaiian Archipelago during December 1990-May 1993. Fifteen sharks were caught farther than 50 n.mi. offshore, indicating that tiger sharks do occur well offshore and removed from benthic topography. About 89% of the sharks were caught during October-March, while only 56% of the fishing effort occurred during that period.

The complex variable boundary element method: Applications in determining approximative boundaries

Science.gov (United States)

Hromadka, T.V.

1984-01-01

The complex variable boundary element method (CVBEM) is used to determine approximation functions for boundary value problems of the Laplace equation such as occurs in potential theory. By determining an approximative boundary upon which the CVBEM approximator matches the desired constant (level curves) boundary conditions, the CVBEM is found to provide the exact solution throughout the interior of the transformed problem domain. Thus, the acceptability of the CVBEM approximation is determined by the closeness-of-fit of the approximative boundary to the study problem boundary. ?? 1984.

The chemistry and mineralogy of haloed burrows in pelagic sediment at DOMES Site A: The equatorial North Pacific

Science.gov (United States)

Piper, D.Z.; Rude, P.D.; Monteith, S.

1987-01-01

The chemical and mineralogical composition of burrowed sediment, recovered in 66 box cores at latitude 9??25???N and longitude 151??15???W in the equatorial Pacific, demonstrates the important role of infauna in determining the geochemistry of pelagic sediment. Haloed burrows, approximately 3 cm across, were present in many of the cores. Within early Tertiary sediment that was covered by less than 5 cm of surface Quaternary sediment in several cores, the burrows in cross-section consist of three units: (1) a dark yellowish-brown central zone of Quaternary sediment surrounded, by (2) a pale yellowish-orange zone (the halo) of Tertiary sediment, which is surrounded by (3) a metal-oxide precipitate; the enclosing Tertiary sediment is dusky brown. Several elements - Mn, Ni, Cu, Co, Zn, Sb and Ce - have been leached from the light-colored halo, whereas Cr, Cs, Hf, Rb, Sc, Ta, Th, U, the rare earth elements exclusive of Ce, and the major oxides have not been leached. The metal-oxide zone, 1-5 mm thick, contains as much as 16% MnO2, as the mineral todorokite. The composition of the todorokite, exclusive of the admixed Tertiary sediment, resembles the composition of the metal deficit of the halo and also the composition of surface ferromanganese nodules that have been interpreted as having a predominantly diagenetic origin. Thus bioturbation contributes not only to the redistribution of metals within pelagic sediment, but also to the accretion of ferromanganese nodules on the sea floor. ?? 1987.

Rock art at the pleistocene/holocene boundary in Eastern South America.

Science.gov (United States)

Neves, Walter A; Araujo, Astolfo G M; Bernardo, Danilo V; Kipnis, Renato; Feathers, James K

2012-01-01

Most investigations regarding the first americans have primarily focused on four themes: when the New World was settled by humans; where they came from; how many migrations or colonization pulses from elsewhere were involved in the process; and what kinds of subsistence patterns and material culture they developed during the first millennia of colonization. Little is known, however, about the symbolic world of the first humans who settled the New World, because artistic manifestations either as rock-art, ornaments, and portable art objects dated to the Pleistocene/Holocene transition are exceedingly rare in the Americas. Here we report a pecked anthropomorphic figure engraved in the bedrock of Lapa do Santo, an archaeological site located in Central Brazil. The horizontal projection of the radiocarbon ages obtained at the north profile suggests a minimum age of 9,370 ± 40 BP, (cal BP 10,700 to 10,500) for the petroglyph that is further supported by optically stimulated luminescence (OSL) dates from sediment in the same stratigraphic unit, located between two ages from 11.7 ± 0.8 ka BP to 9.9 ± 0.7 ka BP. These data allow us to suggest that the anthropomorphic figure is the oldest reliably dated figurative petroglyph ever found in the New World, indicating that cultural variability during the Pleistocene/Holocene boundary in South America was not restricted to stone tools and subsistence, but also encompassed the symbolic dimension.

Negotiating boundaries

DEFF Research Database (Denmark)

Aarhus, Rikke; Ballegaard, Stinne Aaløkke

2010-01-01

to maintain the order of the home when managing disease and adopting new healthcare technology. In our analysis we relate this boundary work to two continuums of visibility-invisibility and integration-segmentation in disease management. We explore five factors that affect the boundary work: objects......, activities, places, character of disease, and collaboration. Furthermore, the processes are explored of how boundary objects move between social worlds pushing and shaping boundaries. From this we discuss design implications for future healthcare technologies for the home.......To move treatment successfully from the hospital to that of technology assisted self-care at home, it is vital in the design of such technologies to understand the setting in which the health IT should be used. Based on qualitative studies we find that people engage in elaborate boundary work...

Eastern European retailers and wholesalers' buying behaviour

DEFF Research Database (Denmark)

Esbjerg, Lars; Stacey, Julia

1999-01-01

During the last ten years, retailing in Eastern Europe has undergone considerable changes. The entry of Western European retail chains into Eastern Europe has helped accelerate the distributive trade of Eastern Europe. But what does it take to sell fish and cheese to retailers and wholesalers...... in Eastern Europe compared to Western Europe? Eastern European buyers attach great importance to other aspects when they list new suppliers and products than does Western European retailing. These are the results of a MAPP study of Eastern European retail and wholesale buying behaviour for fish and cheese....... Low prices and favourable terms of payment are most important when retailers in Eastern Europe buy fish and cheese. Then follows the supplier's range of products, trustworthiness of the supplier and product quality. Eastern European wholesalers also rank price and financial conditions as most...

Administrative Area Boundaries 2 (State Boundaries), Region 9, 2010, NAVTEQ

Data.gov (United States)

U.S. Environmental Protection Agency — NAVTEQ Administrative Area Boundaries 2 (State Boundaries) for Region 9. There are five Administrative Area Boundaries layers (1, 2, 3, 4, 5). These layers contain...

Administrative Area Boundaries 4 (City Boundaries), Region 9, 2010, NAVTEQ

Data.gov (United States)

U.S. Environmental Protection Agency — NAVTEQ Administrative Area Boundaries 4 (City Boundaries) for Region 9. There are five Administrative Area Boundaries layers (1, 2, 3, 4, 5). These layers contain...

{sup 10}Be in rhodochrosite nodules from Neogene sediments along the Galapagos Ridge, equatorial Pacific

Energy Technology Data Exchange (ETDEWEB)

Aldahan, A., E-mail: ala.aldahan@geo.uu.s [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); Department of Geology, United Arab Emirates University, Al Ain (United Arab Emirates); Morad, S. [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); Department of Petroleum Geosciences, Petroleum Institute, Abu Dhabi (United Arab Emirates); Possnert, G. [Tandem Laboratory, Uppsala University, Uppsala (Sweden); Sturesson, U. [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); ElSaiy, A. [Department of Geology, United Arab Emirates University, Al Ain (United Arab Emirates)

2010-04-15

Microcrystalline, calcian rhodochrosite occurs as nodules around burrows in late Neogene pelagic sediments from the Galapagos Ridge in the Guatemala Basin, eastern equatorial Pacific (DSDP Leg 68; Site 503). {sup 10}Be isotope revealed that the rhodochrosite nodules have formed under growth conditions much faster than those reported for Fe-Mn nodules. The overall REE patterns of the nodules and host pelagic sediments indicate element derivation mainly from marine pore water. However, variations in the shale normalised Eu values suggest influx of hydrothermal fluids into mounds area at Galapagos, which is also evidenced by the similar minor and major element contents in the nodules and host sediments.

10Be in rhodochrosite nodules from Neogene sediments along the Galapagos Ridge, equatorial Pacific

International Nuclear Information System (INIS)

Aldahan, A.; Morad, S.; Possnert, G.; Sturesson, U.; ElSaiy, A.

2010-01-01

Microcrystalline, calcian rhodochrosite occurs as nodules around burrows in late Neogene pelagic sediments from the Galapagos Ridge in the Guatemala Basin, eastern equatorial Pacific (DSDP Leg 68; Site 503). 10 Be isotope revealed that the rhodochrosite nodules have formed under growth conditions much faster than those reported for Fe-Mn nodules. The overall REE patterns of the nodules and host pelagic sediments indicate element derivation mainly from marine pore water. However, variations in the shale normalised Eu values suggest influx of hydrothermal fluids into mounds area at Galapagos, which is also evidenced by the similar minor and major element contents in the nodules and host sediments.

A review on broodstock nutrition of marine pelagic spawners: the curious case of the freshwater eels (Anguilla spp.)

DEFF Research Database (Denmark)

Heinsbroek, L.T.N.; Støttrup, J.G.; Jacobsen, C.

2013-01-01

To sustain eel aquaculture, development of reproduction in captivity is vital. The aim of this review is to assess our current knowledge on the nutrition of broodstock eels in order to improve the quality of broodstock under farming conditions, drawing information from wild adult eels and other...... in the eggs of farmed eels were not detrimental. The total free amino acid amount and profile of eel eggs appears much different from other marine pelagic spawners. Nutritional intervention to influence egg composition seems feasible, but responsiveness of farmed eels to induced maturation might also require...

27 CFR 9.98 - Monterey.

Science.gov (United States)

2010-04-01

... along the eastern boundary of the Encinal Y Buena Esperanza Land Grant and the western boundaries of... western boundary of the Cienega del Gabilan Land Grant and the eastern boundary of the El Alisal Land... along the eastern boundary of section 33 to the southeast corner of section 33, T. 19 S., R. 7 E. (6...

Geology and geochemistry of the Middle Proterozoic Eastern Ghat mobile belt and its comparison with the lower crust of the Southern Peninsular shield

Science.gov (United States)

Rao, M. V. Subba

1988-01-01

Two prominent rock suites constitute the lithology of the Eastern Ghat mobile belt: (1) the khondalite suite - the metapelites, and (2) the charnockite suite. Later intrusives include ultramafic sequences, anorthosites and granitic gneisses. The chief structural element in the rocks of the Eastern Ghats is a planar fabric (gneissosity), defined by the alignment of platy minerals like flattened quartz, garnet, sillimanite, graphite, etc. The parallelism between the foliation and the lithological layering is related to isoclinal folding. The major structural trend (axial plane foliation trend) observed in the belt is NE-SW. Five major tectonic events have been delineated in the belt. A boundary fault along the western margin of the Eastern Ghats, bordering the low grade terrain has been substantiated by recent gravity and the deep seismic sounding studies. Field evidence shows that the pyroxene granulites (basic granulites) post-date the khondalite suite, but are older than the charnockites as well as the granitic gneisses. Polyphase metamorphism, probably correlatable with different periods of deformation is recorded. The field relations in the Eastern Ghats point to the intense deformation of the terrain, apparently both before, during and after metamorphism.

Weights, hematology and serum chemistry of seven species of free-ranging tropical pelagic seabirds

Science.gov (United States)

Work, Thierry M.

1996-01-01

I established reference values for weight, hematology, and serum chemistry for seven species of free-ranging Hawaiian tropical pelagic seabirds comprising three orders (Procellariiformes, Pelecaniformes, Charadriiformes) and six families (Procellariidae, Phaethontidae, Diomedeidae, Sulidae, Fregatidae, and Laridae). Species examined included 84 Hawaiian dark-rumped petrels (Pterodoma phaeopygia), 90 wedge-tailed shearwaters (Puffinus pacificus), 151 Laysan albatrosses (Diomedea immutabilis), 69 red-footed boobies (Sula sula), 154 red-tailed tropicbirds (Phaeton rubricauda), 90 great frigatebirds (Fregata minor), and 72 sooty terns (Sterna fuscata). Hematocrit, total plasma solids, total and differential white cell counts, serum glucose, calcium, phosphorus, uric acid, total protein, albumin, globulin, aspartate aminotransferase and creatinine phosphokinase were analyzed. Among and within species, hematology and chemistry values varied with age, sex, season, and island of collection. Despite this variation, order-wide trends were observed.

Earthquake source parameters along the Hellenic subduction zone and numerical simulations of historical tsunamis in the Eastern Mediterranean

Science.gov (United States)

Yolsal-Çevikbilen, Seda; Taymaz, Tuncay

2012-04-01

We studied source mechanism parameters and slip distributions of earthquakes with Mw ≥ 5.0 occurred during 2000-2008 along the Hellenic subduction zone by using teleseismic P- and SH-waveform inversion methods. In addition, the major and well-known earthquake-induced Eastern Mediterranean tsunamis (e.g., 365, 1222, 1303, 1481, 1494, 1822 and 1948) were numerically simulated and several hypothetical tsunami scenarios were proposed to demonstrate the characteristics of tsunami waves, propagations and effects of coastal topography. The analogy of current plate boundaries, earthquake source mechanisms, various earthquake moment tensor catalogues and several empirical self-similarity equations, valid for global or local scales, were used to assume conceivable source parameters which constitute the initial and boundary conditions in simulations. Teleseismic inversion results showed that earthquakes along the Hellenic subduction zone can be classified into three major categories: [1] focal mechanisms of the earthquakes exhibiting E-W extension within the overriding Aegean plate; [2] earthquakes related to the African-Aegean convergence; and [3] focal mechanisms of earthquakes lying within the subducting African plate. Normal faulting mechanisms with left-lateral strike slip components were observed at the eastern part of the Hellenic subduction zone, and we suggest that they were probably concerned with the overriding Aegean plate. However, earthquakes involved in the convergence between the Aegean and the Eastern Mediterranean lithospheres indicated thrust faulting mechanisms with strike slip components, and they had shallow focal depths (h < 45 km). Deeper earthquakes mainly occurred in the subducting African plate, and they presented dominantly strike slip faulting mechanisms. Slip distributions on fault planes showed both complex and simple rupture propagations with respect to the variation of source mechanism and faulting geometry. We calculated low stress drop

Assessing health literacy in the eastern and middle-eastern cultures

OpenAIRE

Nair, Satish Chandrasekhar; Satish, Karthyayani Priya; Sreedharan, Jayadevan; Ibrahim, Halah

2016-01-01

Abstract Background Health literacy is a term employed to assess the ability of people to meet the increasing demands related to health in a rapidly evolving society. Low health literacy can affect the social determinants of health, health outcomes and the use of healthcare services. The purpose of the study was to develop a survey construct to assess health literacy within the context of regional culture. Different socioeconomic status among the Eastern and Middle Eastern countries may restr...

Status and trends of the major roundfish, flatfish, and pelagic fish stocks in the North Sea : Thirty-year overview

DEFF Research Database (Denmark)

Serchuk, F.M.; Kirkegaard, Eskild; Daan, N.

1996-01-01

Changes in the status of the major roundfish, flatfish, and pelagic stocks in the North Sea over the past 30 years are reviewed. Synopses are presented on trends in catches, fishing mortality, spawning-stock biomass, and recruitment for eight stocks (cod, haddock, whiting, saithe, plaice, sole......, herring, and mackerel), together with an evaluation of the current state of these resources and the most resent management advice provided by the ICES Advisory, Committee on Fishery Management. (C) 1996 International Council for the Exploration of the Sea...

Concentrations of radionuclides in reef and lagoon pelagic fish from the Marshall Islands

International Nuclear Information System (INIS)

Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Jokela, T.A.; Brunk, J.L.; Marsh, K.V.

1981-07-01

A radiological survey was conducted from September through November of 1978 to assess the concentrations of persistent man-made radionuclides in the terrestrial and marine environments of 11 atolls and 2 islands of the Northern Marshall Islands. The atolls and islands include Rongelap, Utirik, Taka, Bikar, Rongerik, Ailinginae, Likiep, Jemo, Ailuk, Mejet, Wotho, Ujelang and Bikini. Over 4000 terrestrial and marine samples were collected for radionuclide analysis from 76 different islands. Soils, vegetation, indigenous animals, and cistern and groundwater were collected from the islands. Reef fish, pelagic species, clams, lagoon water, and sediments were obtained from the lagoons. A report is given of all available concentration data for 137 Cs, 90 Sr, /sup 239+240/Pu, 238 Pu, 241 Am as well as naturally occurring 40 K and other gamma emitting radionuclides in tissues and organs of different species of fish collected from the atolls

Gravity and magnetic modelling in the Vrancea Zone, south-eastern Carpathians: Redefinition of the edge of the East European Craton beneath the south-eastern Carpathians

Science.gov (United States)

Bocin, A.; Stephenson, R.; Matenco, L.; Mocanu, V.

2013-11-01

A 2D gravity and magnetic data model has been constructed along a 71 km densely observed profile, called DACIA PLAN GRAV MAN's. The profile crosses part of the nappe pile of the south-eastern Carpathians and includes the seismically active Vrancea Zone and was acquired with the objective to illuminate the basement structure and affinity in this area. The modelling approach was to create an initial model from well constrained geological information, integrate it with previous seismic ray tracing and tomographic models and then alter it outside the a priori constraints in order to reach the best fit between observed and calculated potential field anomalies. The results support a realignment of the position of the TTZ (Tornquist-Teisseyre Zone), the profound tectonic boundary within Europe that separates Precambrian cratonic lithosphere of the East European Craton (EEC) from younger accreted lithosphere of Phanerozoic mobile belts to its west. The TTZ is shown to lie further to the south-west than was previously inferred within Romania, where it is largely obscured by the Carpathian nappes. The crust of the EEC beneath the south-eastern Carpathians is inferred to terminate along a major crustal structure lying just west of the Vrancea seismogenic zone. The intermediate depth seismicity of the Vrancea Zone therefore lies within the EEC lithosphere, generally supporting previously proposed models invoking delamination of cratonic lithosphere as the responsible mechanism.

Biodiversity's big wet secret: the global distribution of marine biological records reveals chronic under-exploration of the deep pelagic ocean.

Directory of Open Access Journals (Sweden)

Thomas J Webb

Full Text Available BACKGROUND: Understanding the distribution of marine biodiversity is a crucial first step towards the effective and sustainable management of marine ecosystems. Recent efforts to collate location records from marine surveys enable us to assemble a global picture of recorded marine biodiversity. They also effectively highlight gaps in our knowledge of particular marine regions. In particular, the deep pelagic ocean--the largest biome on Earth--is chronically under-represented in global databases of marine biodiversity. METHODOLOGY/PRINCIPAL FINDINGS: We use data from the Ocean Biogeographic Information System to plot the position in the water column of ca 7 million records of marine species occurrences. Records from relatively shallow waters dominate this global picture of recorded marine biodiversity. In addition, standardising the number of records from regions of the ocean differing in depth reveals that regardless of ocean depth, most records come either from surface waters or the sea bed. Midwater biodiversity is drastically under-represented. CONCLUSIONS/SIGNIFICANCE: The deep pelagic ocean is the largest habitat by volume on Earth, yet it remains biodiversity's big wet secret, as it is hugely under-represented in global databases of marine biological records. Given both its value in the provision of a range of ecosystem services, and its vulnerability to threats including overfishing and climate change, there is a pressing need to increase our knowledge of Earth's largest ecosystem.

The Southern Oscillation, Hypoxia, and the Eastern Pacific Tuna Fishery

Science.gov (United States)

Webster, D.; Kiefer, D.; Lam, C. H.; Harrison, D. P.; Armstrong, E. M.; Hinton, M.; Luo, L.

2012-12-01

The Eastern Pacific tuna fishery, which is one of the world's major fisheries, covers thousands of square kilometers. The vessels of this fishery are registered in more than 30 nations and largely target bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis), and yellowfin (T. albacores) tuna. In both the Pelagic Habitat Analysis Module project, which is sponsored by NASA, and the Fishscape project, which is sponsored by NSF, we have attempted to define the habitat of the three species by matching a 50 year time series on fish catch and effort with oceanographic information obtained from satellite imagery and from a global circulation model. The fishery time series, which was provided by the Inter-American Tropical Tuna Commission, provided spatial maps of catch and effort at monthly time steps; the satellite imagery of the region consisted of sea surface temperature, chlorophyll, and height from GHRSST, SEAWiFS, and AVISO products, and the modeled flow field at selected depths was output from ECCO-92 simulations from 1992 to present. All information was integrated and analyzed within the EASy marine geographic information system. This GIS will also provides a home for the Fishscape spatial simulation model of the coupled dynamics of the ocean, fish, fleets, and markets. This model will then be applied to an assessment of the potential ecological and economic impacts of climate change, technological advances in fleet operations, and increases in fuel costs. We have determined by application of EOF analysis that the ECCO-2 simulation of sea surface height fits well with that of AVISO imagery; thus, if driven properly by predictions of future air-sea exchange, the model should provide good estimates of circulation patterns. We have also found that strong El Nino events lead to strong recruitment of all three species and strong La Nina events lead to weak recruitment. Finally, we have found that the general spatial distribution of the Eastern Pacific fishing grounds

Beyond the climate envelope: using trait filtering models to predict biome boundaries from plant physiology.

Science.gov (United States)

Fisher, R.; Hoffmann, W. A.; Muszala, S.

2014-12-01

The introduction of second-generation dynamic vegetation models - which simulate the distribution of light resources between plant types along the vertical canopy profile, and therefore facilitate the representation of plant competition explicitly - is a large increase in the complexity and fidelity with which the terrestrial biosphere is abstracted into Earth System Models. In this new class of model, biome boundaries are predicted as the emergent properties of plant physiology, and are therefore sensitive to the high-dimensional parameterizations of plant functional traits. These new approaches offer the facility to quantitatively test ecophysiological hypotheses of plant distribution at large scales, a field which remains surprisingly under-developed. Here we describe experiments conducted with the Community Land Model Ecosystem Demography component, CLM(ED), in which we reduce the complexity of the problem by testing how individual plant functional trait changes to control the location of biome boundaries between functional types. Specifically, we investigate which physiological trade-offs determine the boundary between frequently burned savanna and forest biomes, and attempt to distinguish how each strategic life-history trade-off (carbon storage, bark investment, re-sprouting strategy) contributes towards the maintenance of sharp geographical gradients between fire adapted and typically inflammable closed canopy ecosystems. This study forms part of the planning for a model-inspired fire manipulation experiment at the cerrado-forest boundary in South-Eastern Brazil, and the results will be used to guide future data-collection and analysis strategies.

Boundary-value problems with free boundaries for elliptic systems of equations

CERN Document Server

Monakhov, V N

1983-01-01

This book is concerned with certain classes of nonlinear problems for elliptic systems of partial differential equations: boundary-value problems with free boundaries. The first part has to do with the general theory of boundary-value problems for analytic functions and its applications to hydrodynamics. The second presents the theory of quasiconformal mappings, along with the theory of boundary-value problems for elliptic systems of equations and applications of it to problems in the mechanics of continuous media with free boundaries: problems in subsonic gas dynamics, filtration theory, and problems in elastico-plasticity.

Comparative ecology of widely distributed pelagic fish species in the North Atlantic: Implications for modelling climate and fisheries impacts

Science.gov (United States)

Trenkel, V. M.; Huse, G.; MacKenzie, B. R.; Alvarez, P.; Arrizabalaga, H.; Castonguay, M.; Goñi, N.; Grégoire, F.; Hátún, H.; Jansen, T.; Jacobsen, J. A.; Lehodey, P.; Lutcavage, M.; Mariani, P.; Melvin, G. D.; Neilson, J. D.; Nøttestad, L.; Óskarsson, G. J.; Payne, M. R.; Richardson, D. E.; Senina, I.; Speirs, D. C.

2014-12-01

This paper reviews the current knowledge on the ecology of widely distributed pelagic fish stocks in the North Atlantic basin with emphasis on their role in the food web and the factors determining their relationship with the environment. We consider herring (Clupea harengus), mackerel (Scomber scombrus), capelin (Mallotus villosus), blue whiting (Micromesistius poutassou), and horse mackerel (Trachurus trachurus), which have distributions extending beyond the continental shelf and predominantly occur on both sides of the North Atlantic. We also include albacore (Thunnus alalunga), bluefin tuna (Thunnus thynnus), swordfish (Xiphias gladius), and blue marlin (Makaira nigricans), which, by contrast, show large-scale migrations at the basin scale. We focus on the links between life history processes and the environment, horizontal and vertical distribution, spatial structure and trophic role. Many of these species carry out extensive migrations from spawning grounds to nursery and feeding areas. Large oceanographic features such as the North Atlantic subpolar gyre play an important role in determining spatial distributions and driving variations in stock size. Given the large biomasses of especially the smaller species considered here, these stocks can exert significant top-down pressures on the food web and are important in supporting higher trophic levels. The review reveals commonalities and differences between the ecology of widely distributed pelagic fish in the NE and NW Atlantic basins, identifies knowledge gaps and modelling needs that the EURO-BASIN project attempts to address.

Recurrent uranium relocations in distal turbidites emplaced in pelagic conditions

International Nuclear Information System (INIS)

Colley, S.; Thomson, J.

1985-01-01

The sediments of the Madeira Abyssal Plain, east of Great Meteor Seamount, are dominated by distal turbidite deposition. While the turbidites exhibit a wide compositional range, individual examples can be correlated over a wide area and are relatively homogeneous. Organic C oxidation, by bottom water oxygen, proceeds from the turbidite tops downwards after emplacement in pelagic conditions, and the progress of this oxidation front is marked by a sharp colour contrast in the sediments. In turbidites with Csub(org) > 0.5%, redistribution of authigenic U occurs to form a concentration peak (4 to 9 ppm U), just below the oxidation front or colour change. Several tens μg U/cm 2 may be mobilised, and in all examples studied > 60% of the remobilised U is relocated into the peak. Following burial by subsequent turbidites, such U concentration peaks are persistent as relict indicators of their extinct oxidation fronts for at least 2 x 10 5 years. In the case of thin turbidites where labile Csub(org) is almost exhausted, the U peaks may be located in underlying sedimentary units because of their relationship to the oxidation front. A redox mechanism for U peak formation is suggested from these data rather than a complexation with organic matter. (author)

Competition and niche separation of pelagic bacteria in freshwater habitats.

Science.gov (United States)

Pernthaler, Jakob

2017-06-01

Freshwater bacterioplankton assemblages are composed of sympatric populations that can be delineated, for example, by ribosomal RNA gene relatedness and that differ in key ecophysiological properties. They may be free-living or attached, specialized for particular concentrations or subsets of substrates, or invest a variable amount of their resources in defence traits against protistan predators and viruses. Some may be motile and tactic whereas others are not, with far-reaching implications for their respective life styles and niche partitioning. The co-occurrence of competitors with overlapping growth requirements has profound consequences for the stability of community functions; it can to some extent be explained by habitat factors such as the microscale complexity and spatiotemporal variability of the lacustrine environments. On the other hand, the composition and diversity of freshwater microbial assemblages also reflects non-equilibrium states, dispersal and the stochasticity of community assembly processes. This review synoptically discusses the competition and niche separation of heterotrophic bacterial populations (defined at various levels of phylogenetic resolution) in the pelagic zone of inland surface waters from a variety of angles, focusing on habitat heterogeneity and the resulting biogeographic distribution patterns, the ecophysiological adaptations to the substrate field and the interactions of prokaryotes with predators and viruses. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Hydrological and environmental variables outperform spatial factors in structuring species, trait composition, and beta diversity of pelagic algae.

Science.gov (United States)

Wu, Naicheng; Qu, Yueming; Guse, Björn; Makarevičiūtė, Kristė; To, Szewing; Riis, Tenna; Fohrer, Nicola

2018-03-01

There has been increasing interest in algae-based bioassessment, particularly, trait-based approaches are increasingly suggested. However, the main drivers, especially the contribution of hydrological variables, of species composition, trait composition, and beta diversity of algae communities are less studied. To link species and trait composition to multiple factors (i.e., hydrological variables, local environmental variables, and spatial factors) that potentially control species occurrence/abundance and to determine their relative roles in shaping species composition, trait composition, and beta diversities of pelagic algae communities, samples were collected from a German lowland catchment, where a well-proven ecohydrological modeling enabled to predict long-term discharges at each sampling site. Both trait and species composition showed significant correlations with hydrological, environmental, and spatial variables, and variation partitioning revealed that the hydrological and local environmental variables outperformed spatial variables. A higher variation of trait composition (57.0%) than species composition (37.5%) could be explained by abiotic factors. Mantel tests showed that both species and trait-based beta diversities were mostly related to hydrological and environmental heterogeneity with hydrological contributing more than environmental variables, while purely spatial impact was less important. Our findings revealed the relative importance of hydrological variables in shaping pelagic algae community and their spatial patterns of beta diversities, emphasizing the need to include hydrological variables in long-term biomonitoring campaigns and biodiversity conservation or restoration. A key implication for biodiversity conservation was that maintaining the instream flow regime and keeping various habitats among rivers are of vital importance. However, further investigations at multispatial and temporal scales are greatly needed.

Ecological distribution of pelagic copepods and species relationship to acidification, liming and natural recovery in a boreal area

Directory of Open Access Journals (Sweden)

Svein Birger WÆRVÅGEN

2003-02-01

Full Text Available Distribution and ecology of pelagic copepods were studied in a boreal area strongly affected by acidification in southern Norway. Differential regional composition of bedrock geology and Quaternary deposits combined with liming have produced aquatic sites with contrasting acidification and recovery histories. The omnivorous species Eudiaptomus gracilis showed a striking ability to tolerate both acidification and chemical recovery. The predominantly carnivorous species Heterocope saliens increased numerically during acidification, both because it is tolerant to acidic environments and because fish predation diminished or disappeared altogether. After chemical recovery, H. saliens, having an endogenous egg-bank, most readily produced viable populations with numerical abundance depending upon fish predation pressure. Thermocyclops oithonoides and Cyclops scutifer were negatively affected by strongly acidic environments, whereas Mesocyclops leuckarti tolerated acidic conditions better. All three cyclopoid species increased in abundance after chemical recovery, most probably from small residual populations. The hypolimnetic C. scutifer faced dispersal problems in re-establishing following liming. Deep lakes (>20 m harboured considerable residual populations of C. scutifer which recovered rapidly to pre-acidic conditions. Cyclops abyssorum inhabited the pelagial during early recovery of formerly chronically acidified lakes as a fugitive species, probably due to rapid dispersal capacities. Littoral cyclopoids, such as Acanthocyclops vernalis and Diacyclops nanus, were commonly distributed in the free waters of the most acidic lakes (pH = 4.5-4.8, but disappeared from the pelagial shortly after chemical recovery. The total community of pelagic copepods forms a promising tool to identify historical acidification and trajectories of recovery in the freshwater environment.

Role of Transtension in Rifting at the Pacific-North America Plate Boundary

Science.gov (United States)

Stock, J. M.

2011-12-01

Transtensional plate motion can be accommodated either in a localized zone of transtensional rifting or over a broader region. Broader zones of deformation can be classified either as diffuse deformation or strain partitioning (one or more major strike-slip shear zones geographically offset from a region of a extensional faulting). The Pacific-North America plate boundary in southwestern North America was transtensional during much of its history and has exhibited the full range of these behaviors at different spatial scales and in different locations, as recorded by fault motions and paleomagnetic rotations. Here we focus on the northern Gulf of California part of the plate boundary (Upper and Lower Delfin basin segments), which has been in a zone of transtensional Pacific-North America plate boundary motion ever since the middle Miocene demise of adjacent Farallon-derived microplates. Prior to the middle Miocene, during the time of microplate activity, this sector of North America experienced basin-and-range normal faults (core complexes) in Sonora. However there is no evidence of continued extensional faulting nor of a Gulf-related topographic depression until after ca 12 Ma when a major ignimbrite (Tuff of San Felipe/ Ignimbrite of Hermosillo) was deposited across the entire region of the future Gulf of California rift in this sector. After 12 Ma, faults disrupted this marker bed in eastern Baja California and western Sonora, and some major NNW-striking right-lateral faults are inferred to have developed near the Sonoran coast causing offset of some of the volcanic facies. However, there are major tectonic rotations of the volcanic rocks in NE Baja California between 12 and 6 Ma, suggesting that the plate boundary motion was still occurring over a broad region. By contrast, after about 6 Ma, diminished rotations in latest Miocene and Pliocene volcanic rocks, as well as fault slip histories, show that plate boundary deformation became localized to a narrower

Evidence of a variable "unsampled" pelagic fish biomass in shallow water (< 20 m): the case of the Gulf of Lion

OpenAIRE

Brehmer, Patrice; Guillard, J.; Guennegan, Y.; Bigot, J.L.; Liorzou, B.

2006-01-01

Studies of small pelagic fish biomass are limited by the fact that research vessels and fishing boats are usually restricted to working areas with a bottom depth > 20 m. Consequently, "unsampled" areas can represent a large proportion of the continental shelf, and the biomass in those areas can be important and must be taken into account in assessment methods in order to avoid misleading interpretations in population dynamics. A time-series tell years long has been compiled from acoustic-asse...

Model-based estimation with boundary side information or boundary regularization [cardiac emission CT].

Science.gov (United States)

Chiao, P C; Rogers, W L; Fessler, J A; Clinthorne, N H; Hero, A O

1994-01-01

The authors have previously developed a model-based strategy for joint estimation of myocardial perfusion and boundaries using ECT (emission computed tomography). They have also reported difficulties with boundary estimation in low contrast and low count rate situations. Here they propose using boundary side information (obtainable from high resolution MRI and CT images) or boundary regularization to improve both perfusion and boundary estimation in these situations. To fuse boundary side information into the emission measurements, the authors formulate a joint log-likelihood function to include auxiliary boundary measurements as well as ECT projection measurements. In addition, they introduce registration parameters to align auxiliary boundary measurements with ECT measurements and jointly estimate these parameters with other parameters of interest from the composite measurements. In simulated PET O-15 water myocardial perfusion studies using a simplified model, the authors show that the joint estimation improves perfusion estimation performance and gives boundary alignment accuracy of <0.5 mm even at 0.2 million counts. They implement boundary regularization through formulating a penalized log-likelihood function. They also demonstrate in simulations that simultaneous regularization of the epicardial boundary and myocardial thickness gives comparable perfusion estimation accuracy with the use of boundary side information.

Phylogeography of Eastern Grey Kangaroos, Macropus giganteus, Suggests a Mesic Refugium in Eastern Australia.

Directory of Open Access Journals (Sweden)

Brett A Coghlan

Full Text Available Phylogeographic studies around the world have identified refugia where fauna were able to persist during unsuitable climatic periods, particularly during times of glaciation. In Australia the effects of Pleistocene climate oscillations on rainforest taxa have been well studied but less is known about the effects on mesic-habitat fauna, such as the eastern grey kangaroo (Macropus giganteus. The eastern grey kangaroo is a large mammal that is common and widespread throughout eastern Australia, preferring dry mesic habitat, rather than rainforest. As pollen evidence suggests that the central-eastern part of Australia (southeast Queensland and northern New South Wales experienced cycles of expansion in mesic habitat with contraction in rainforests, and vice versa during glacial and interglacial periods, respectively, we hypothesise that the distribution of the eastern grey kangaroo was affected by these climate oscillations and may have contracted to mesic habitat refugia. From 375 mitochondrial DNA control region sequences from across the distribution of eastern grey kangaroos we obtained 108 unique haplotypes. Phylogenetic analysis identified two clades in Queensland, one of which is newly identified and restricted to a small coastal region in southern Queensland north of Brisbane, known as the Sunshine Coast. The relatively limited geographic range of this genetically isolated clade suggests the possibility of a mesic habitat refugium forming during rainforest expansion during wetter climate cycles. Other potential, although less likely, reasons for the genetic isolation of the highly distinct clade include geographic barriers, separate northward expansions, and strong local adaptation.

Phylogeography of Eastern Grey Kangaroos, Macropus giganteus, Suggests a Mesic Refugium in Eastern Australia.

Science.gov (United States)

Coghlan, Brett A; Goldizen, Anne W; Thomson, Vicki A; Seddon, Jennifer M

2015-01-01

Phylogeographic studies around the world have identified refugia where fauna were able to persist during unsuitable climatic periods, particularly during times of glaciation. In Australia the effects of Pleistocene climate oscillations on rainforest taxa have been well studied but less is known about the effects on mesic-habitat fauna, such as the eastern grey kangaroo (Macropus giganteus). The eastern grey kangaroo is a large mammal that is common and widespread throughout eastern Australia, preferring dry mesic habitat, rather than rainforest. As pollen evidence suggests that the central-eastern part of Australia (southeast Queensland and northern New South Wales) experienced cycles of expansion in mesic habitat with contraction in rainforests, and vice versa during glacial and interglacial periods, respectively, we hypothesise that the distribution of the eastern grey kangaroo was affected by these climate oscillations and may have contracted to mesic habitat refugia. From 375 mitochondrial DNA control region sequences from across the distribution of eastern grey kangaroos we obtained 108 unique haplotypes. Phylogenetic analysis identified two clades in Queensland, one of which is newly identified and restricted to a small coastal region in southern Queensland north of Brisbane, known as the Sunshine Coast. The relatively limited geographic range of this genetically isolated clade suggests the possibility of a mesic habitat refugium forming during rainforest expansion during wetter climate cycles. Other potential, although less likely, reasons for the genetic isolation of the highly distinct clade include geographic barriers, separate northward expansions, and strong local adaptation.

Age- and size-dependent mating performance and fertility in a pelagic copepod, Temora longicornis

DEFF Research Database (Denmark)

Sichlau, Mie Hylstofte; Kiørboe, Thomas

2011-01-01

Prepress abstract: In many species, size and age have been shown to be strong determinants of the reproductive success for both sexes. Here we examine age- and size dependent reproductive performance (egg- and sperm production, mating success) in a pelagic copepod. Compared to smaller males, larger...... males produce larger spermatophores containing more spermatozoa, and fertilize a larger fraction of available females. Females mating with large males produce more offspring than those mating with small males. Similarly, large females have higher egg production rates as well as a higher life-time egg...... fertilize females for only about eight days after they mature. The strong size- and age-dependent fertility observed in this species is conducive to the development of sexual selection via mate choice for young and large partners, as has been shown in one other copepod species...

Boundary organizations to boundary chains: Prospects for advancing climate science application

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Christine J. Kirchhoff

2015-01-01

Full Text Available Adapting to climate change requires the production and use of climate information to inform adaptation decisions. By facilitating sustained interaction between science producers, boundary organizations narrow the gap between science and decision-making and foster the co-production of actionable knowledge. While traditional boundary organization approaches focused on intense one-on-one interactions between producers and users increases usability, this approach requires significant time and resources. Forming “boundary chains”, linking complimentary boundary organizations together, may reduce those costs. In this paper, we use longitudinal observations of a boundary chain, interviews and surveys to explore: (1 how producer-user interactions increase understanding and information usability and (2 if and how efficiencies in climate information production, dissemination and use arise as a result of the boundary chain. We find that forming and sustaining an effective boundary chain requires not only interest, commitment and investment from every link in the chain but also a level of non-overlapping mutual dependency and complementary skill sets. In this case, GLISA’s strength in producing scientific information and their credibility as climate scientists and HRWC’s strengths in facilitation, connection with potential information users, and their recognition and reputation in the watershed add value to the boundary chain enabling the boundary chain to accomplish more with greater efficiency than if each organization in the chain tried to work independently. Finally, data show how the boundary chain increased efficiencies in educating potential users about the strengths and limitations of climate science and improving the production, dissemination, and use of climate information.

Anticipating the free amino acid concentrations in newly hatched pelagic fish larvae based on recently fertilized eggs and temperature

DEFF Research Database (Denmark)

Rayner, Thomas Allan; Hwang, Jiang-Shiou; Hansen, Benni Winding

2017-01-01

between the species for different FAAs was low, and the most outstanding essential FAAs were leucine, lysine, valine and isoleucine while alanine and serine dominated non-essential FAAs. Overall, leucine could be regarded as the most important among all species due to its common occurrence in newly...... spawned eggs and fast rate of decay. Based on the functions considered in the present study, it is possible to anticipate the availability of FAA diet needed in the form of live feed for pelagic first feeding marine fish larvae in aquaculture at different temperatures....

Use of photogrammetry as a means to assess hybrids of rhesus (Macaca mulatta) and long-tailed (M. fascicularis) macaques.

Science.gov (United States)

Jadejaroen, Janya; Hamada, Yuzuru; Kawamoto, Yoshi; Malaivijitnond, Suchinda

2015-01-01

Rhesus (Macaca mulatta) and long-tailed (M. fascicularis) macaques are the most commonly used non-human primate models for biomedical research, but it is difficult to identify these two species in the hybrid zone (15-20°N). In this work, we used morphological values obtained via photogrammetry to assess hybrids of rhesus and long-tailed macaques at Khao Khieow Open Zoo (KKZ; 13°21'N, 101°06'E), eastern Thailand. Long-tailed and rhesus macaques have species-specific tail lengths and contrasts of their yellowish pelages. The accuracy and precision of the relative tail length (%RTL) and the contrast of the yellow hue (Cb*) of the pelage, as obtained from photographs, were compared with the corresponding direct measurements (morphometrics). The photogrammetric and morphometric measurements of %RTL and Cb* were highly significantly correlated (r = 0.989 and 0.980, p photogrammetry can be utilized to identify macaque species or hybrids when species identification relies mainly on tail length and pelage color.

Rugose corals across the Devonian-Carboniferous boundary in NW Turkey

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Julien Denayer

2016-02-01

Full Text Available An uppermost Famennian (Strunian coral assemblage has been recovered in the middle part of the Yılanlı Formation of the Istanbul Zone (Zonguldak and Bartın areas, NW Turkey. In the Bartın area, the studied fossiliferous interval corresponds to a c. 30 m-thick unit of bioclastic to peloidal wackestone to packstone grading to grainstone and including two stromatoporoid biostromes. In the Zonguldak area, 60 km westward, the bioclastic facies is dominant. The rugose corals are mainly solitary taxa belonging to the genera Campophyllum, Bounophyllum, Amplexocarinia, and ?Metriophyllum, and only one colonial genus occurs: Pseudoendophyllum. This fauna is similar to that documented in Europe. The campophyllids and dibunophyllids are the main component of the uppermost Famennian assemblages in S Belgium, N France, W Germany, NW and S Poland. The endophyllids occur in S Poland, Novaya Zemlya, and in the Ural Mountains. The Istanbul Zone is supposed to be situated in the central part of the Palaeotethys Ocean, along the southern margin of Laurussia during the uppermost Devonian and Carboniferous. The rugose corals indicate some relationship with the eastern part of Laurussia, or that both areas were under a common marine influence at this time. The global Hangenberg event was not recognized in the Turkish localities, except for the disappearance of the corals, occurring less than 19 m below the Devonian–Carboniferous boundary based on the foraminifers. There is no major facies change through the boundary and the first Carboniferous corals (small Uralinia and Caninophyllum appear 6 m above the D–C boundary. The new species Caninophyllum charli sp. nov. is described from the upper part of the lower Tournaisian.

27 CFR 9.139 - Santa Lucia Highlands.

Science.gov (United States)

2010-04-01

... coincides with the western boundary of the Guadalupe Y Llanitos de los Correos Land Grant and the eastern... eastern boundary of section 28 T. 165., R. 4E., coincides with the western boundary of the Guadalupe Y... coincides with the unnamed light duty road for about 0.4 miles and then with the eastern boundaries of...

50 CFR Table 1 to Part 680 - Crab Rationalization (CR) Fisheries

Science.gov (United States)

2010-10-01

... Eastern Bering Sea Tanner crab (Chionoecetes bairdi) In waters of the EEZ with: (1) A western boundary the... camtshaticus) In waters of the EEZ with: (1) An eastern boundary the longitude 179° W. long., (2) A western... eastern boundary the longitude of 166° W. long., (2) A northern and western boundary of the Maritime...

Biodiversity, Community and Trophic Structure of the Suprabenthos of the Gulf of Cádiz-Guadalquivir Estuary Coupled System: Linking Pelagic-Benthic and Terrestrial-Marine Ecosystems.

Science.gov (United States)

Vilas, C.

2016-02-01

Suprabenthos biodiversity and species densities on both offshore and coastal systems are largely unknown. Main components like mysids, euphasiids or amphipods are omnivorous and constitute a major dietary component for many benthic and pelagic fishes, mammals, cephalopods and decapods. Despite their relevant ecological role linking pelagic-benthic food webs, suprabenthos have been chronically undersampled and their components underrepresented and underestimated in food web models. Many pelagic and demersal species of high commercial and ecological interest at the Gulf of Cádiz (GoC) feed at a bottom scattering layer identified from 0 to 200 m depth and up to 50 km from coast, related to the Guadalquivir Estuary (GE) influence coastal area, and present life history cycles based on a sequential use of habitats from GoC to GE nursery area, may be adapted to match the horizontal migrations of key suprabenthos prey species. In order to understand the ecological mechanisms through which the GE-GoC coupled ecosystem would influence the recruitment of these fishery resources, the suprabenthos was sampled by suprabenthic sldege (200 μm) from the shallow estuary to 75 m depth during June, August and November of 2013. We identified up to 300 species (H index 0.4-2-9 and Beta diversity 0.55), being copepods, molluscs, cumacea, cladocera, poliquets, decapods, mysids and amphipods the most important groups by biomass (mg/m3), finding densities up to 32.9 mg/m3 for copepods, 6 for mysids and up to 100 mg/m3 for decapods. Multivariate analysis determines depth as the most important variable explaining community structure, decreasing biodiversity with depth, while for sites at depths species show seasonal horizontal migrations between GoC and GE, connecting terrestrial and marine ecosystems.

Seasonal dynamics and life histories of pelagic cladocerans (Crustacea; Cladocera in an acid boreal lake

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Jens Petter NILSSEN

2011-02-01

Full Text Available In the surveyed anthropogenic acidified Lake Gjerstadvann with pH ≈ 5.2 situated in southern Norway, spatial and temporal distribution of three characteristic planktonic cladocerans inhabiting acidified boreal biotopes, Bosmina longispina, Holopedium gibberum, and Diaphanosoma brachyurum, were studied over a period of one year. The major pelagic predator was Eurasian perch, Perca fluviatilis. The local perch probably balanced the cladoceran community and facilitated co-existence of all three species of cladocerans by removing significant portions of B. longispina, which could also be the case in similar types of boreal lakes. Invertebrate predators such as the dipteran larvae Chaoborus flavicans and carnivorous copepods did not seem to influence the cladoceran community. B. longispina was perennial, whereas both H. gibberum and D. brachyurum were recorded only during the ice-free period. The life cycle of these free-living pelagic species ranged from 2-3 in D. brachyurum, 3 in H. gibberum to approximately 6 annual generations in B. longispina. Wintering took place as resting eggs in D. brachyurum and H. gibberum, while B. longispina produced resting eggs in addition to an active planktonic stay. The warm water tolerant D. brachyurum was mainly distributed above the thermocline, whereas H. gibberum also inhabited deeper strata, and B. longispina most vertical strata of the lake. Maximum seasonal clutch volume of B. longispina coincided in time with peak in food abundance and may be a useful parameter to identify planktonic food availability in such lakes. Knowledge of the autecology and life history of species is fundamental for understanding ecosystem stress, such as anthropogenic acidification and recovery through liming or by natural causes. Seasonal depth isoplots combined with life history studies of commonly co-occurring cladoceran species from natural acid and anthropogenic acidified lakes on the Northern Hemisphere seem to be uncommon

Spatial and body-size dependent response of marine pelagic communities to projected global climate change.

Science.gov (United States)

Lefort, Stelly; Aumont, Olivier; Bopp, Laurent; Arsouze, Thomas; Gehlen, Marion; Maury, Olivier

2015-01-01

Temperature, oxygen, and food availability directly affect marine life. Climate models project a global warming of the ocean's surface (~+3 °C), a de-oxygenation of the ocean's interior (~-3%) and a decrease in total marine net primary production (~-8%) under the 'business as usual' climate change scenario (RCP8.5). We estimated the effects of these changes on biological communities using a coupled biogeochemical (PISCES)--ecosystems (APECOSM) model forced by the physical outputs of the last generation of the IPSL-CM Earth System Model. The APECOSM model is a size-structured bio-energetic model that simulates the 3D dynamical distributions of three interactive pelagic communities (epipelagic, mesopelagic, and migratory) under the effects of multiple environmental factors. The PISCES-APECOSM model ran from 1850 to 2100 under historical forcing followed by RCP8.5. Our RCP8.5 simulation highlights significant changes in the spatial distribution, biomass, and maximum body-size of the simulated pelagic communities. Biomass and maximum body-size increase at high latitude over the course of the century, reflecting the capacity of marine organisms to respond to new suitable environment. At low- and midlatitude, biomass and maximum body-size strongly decrease. In those regions, large organisms cannot maintain their high metabolic needs because of limited and declining food availability. This resource reduction enhances the competition and modifies the biomass distribution among and within the three communities: the proportion of small organisms increases in the three communities and the migrant community that initially comprised a higher proportion of small organisms is favored. The greater resilience of small body-size organisms resides in their capacity to fulfill their metabolic needs under reduced energy supply and is further favored by the release of predation pressure due to the decline of large organisms. These results suggest that small body-size organisms might be

Dolphinfish Bycatch in Spanish Mediterranean Large Pelagic Longline Fisheries, 2000–2010

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David Macías

2012-01-01

Full Text Available The aim of this paper is to describe the dolphinfish bycatch rates in the longline fisheries of the Western Mediterranean and modelling the nominal bycatch abundance and distribution of dolphinfish from the Spanish Mediterranean as a function of technical, geographical, and seasonality factors. Our results indicate that the impact of the pelagic and semipelagic longline on the dolphinfish population is relatively low (1.083 fishes per 1000 hooks, in contrast with the greater effect on the target species population. We obtained a statistically significant logistic model, with the following factors: technical characteristics of the fishery, geographical location, and seasonality. Drifting surface longliners targeting albacore is the gear with the highest effect on Mediterranean dolphinfish population. The technical characteristics of the fishery and seasonality factors have an important role in explaining the absence or presence of dolphinfish bycatch in the different boat strata, gear types, and seasons. Moreover, sea surface temperature and lunar phases also present additional explanations. Lunar phase as SST has been frequently used as an explanatory variable affecting catch rates of dolphinfish.

Water masses, ocean fronts, and the structure of Antarctic seabird communities: putting the eastern Bellingshausen Sea in perspective

Science.gov (United States)

Ribic, Christine A.; Ainley, David G.; Ford, R. Glenn; Fraser, William R.; Tynan, Cynthia T.; Woehler, Eric J.

2015-01-01

Waters off the western Antarctic Peninsula (i.e., the eastern Bellingshausen Sea) are unusually complex owing to the convergence of several major fronts. Determining the relative influence of fronts on occurrence patterns of top-trophic species in that area, therefore, has been challenging. In one of the few ocean-wide seabird data syntheses, in this case for the Southern Ocean, we analyzed ample, previously collected cruise data, Antarctic-wide, to determine seabird species assemblages and quantitative relationships to fronts as a way to provide context to the long-term Palmer LTER and the winter Southern Ocean GLOBEC studies in the eastern Bellingshausen Sea. Fronts investigated during both winter (April–September) and summer (October–March) were the southern boundary of the Antarctic Circumpolar Current (ACC), which separates the High Antarctic from the Low Antarctic water mass, and within which are embedded the marginal ice zone and Antarctic Shelf Break Front; and the Antarctic Polar Front, which separates the Low Antarctic and the Subantarctic water masses. We used clustering to determine species' groupings with water masses, and generalized additive models to relate species' densities, biomass and diversity to distance to respective fronts. Antarctic-wide, in both periods, highest seabird densities and lowest species diversity were found in the High Antarctic water mass. In the eastern Bellingshausen, seabird density in the High Antarctic water mass was lower (as low as half that of winter) than found in other Antarctic regions. During winter, Antarctic-wide, two significant species groups were evident: one dominated by Adélie penguins (Pygoscelis adeliae) (High Antarctic water mass) and the other by petrels and prions (no differentiation among water masses); in eastern Bellingshausen waters during winter, the one significant species group was composed of species from both Antarctic-wide groups. In summer, Antarctic-wide, a High Antarctic group

Brain response to prosodic boundary cues depends on boundary position

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Julia eHolzgrefe

2013-07-01

Full Text Available Prosodic information is crucial for spoken language comprehension and especially for syntactic parsing, because prosodic cues guide the hearer’s syntactic analysis. The time course and mechanisms of this interplay of prosody and syntax are not yet well understood. In particular, there is an ongoing debate whether local prosodic cues are taken into account automatically or whether they are processed in relation to the global prosodic context in which they appear. The present study explores whether the perception of a prosodic boundary is affected by its position within an utterance. In an event-related potential (ERP study we tested if the brain response evoked by the prosodic boundary differs when the boundary occurs early in a list of three names connected by conjunctions (i.e., after the first name as compared to later in the utterance (i.e., after the second name. A closure positive shift (CPS — marking the processing of a prosodic phrase boundary — was elicited only for stimuli with a late boundary, but not for stimuli with an early boundary. This result is further evidence for an immediate integration of prosodic information into the parsing of an utterance. In addition, it shows that the processing of prosodic boundary cues depends on the previously processed information from the preceding prosodic context.

Environmental protection in Eastern Europe

International Nuclear Information System (INIS)

Kabala, S.

1990-01-01

There is a need for the development of institutional structures to make the transfer of technology work to improve the ability of Eastern Europe to find solutions to its environmental problems. Envisioned is technical assistance: U.S. experts who will work on-site with Eastern European experts. The idea is to technically train individuals in pollution-prevention methods. Trained experts could then upgrade processes to save input, energy, and materials. In the exchange of environmental information, discussions have led to four issues: it is expensive to transfer equipment and make qualified personnel available for a long period; information is comparatively inexpensive to convey; in Eastern Europe there are trained and competent personnel; the theoretical knowledge, academic knowledge, and education are at a very high level but little of this knowledge has been put into practice. The technology transfer goal is to develop a response to needs identified by partner institutions and counterpart professionals that will enable Eastern Europe to tap resources that do exist- scientific, managerial, and economic resources and tap information resources in the US in order to address the environmental problems that exist in Eastern Europe

An assessment, using stable isotopes, of the importance of allochthonous organic carbon sources to the pelagic food web in Loch Ness

Science.gov (United States)

Jones, R. I.; Grey, J.; Sleep, D.; Quarmby, C.

1998-01-01

The natural abundance of stable isotopes (δ13C and δ1315N) was determined for components of the pelagic food web in Loch Ness, a deep oligotrophic lake in northern Scotland, and compared with values from the inflow rivers and the catchment vegetation. Phytoplankton δ13C was low compared to values reported from other lakes, possibly reflecting a high use of 13C-depleted carbon dioxide from respired organic matter before further isotopic fractionation during photosynthesis. Phytoplankton δ13C was appreciably lower than that of dissolved and particulate organic matter (DOM and POM) in the loch. The DOM and POM were evidently overwhelmingly of allochthonous origin and ultimately derived from terrestrial plant detritus. The distinctive δ13C values for phytoplankton and detritus in the loch allowed the use of food sources by grazing crustacean zooplankton to be assessed, and the contributions of phytoplankton carbon and detrital carbon to zooplankton total body carbon appeared to be about equal. Comparison of δ13C and δ15N values for zooplankton and fish allowed assessment of trophic structure in the loch. The very high dependence of the pelagic food web in Loch Ness on allochthonous organic matter inputs from the catchment may be exceptional in a large lake, but has important implications for our understanding of lake ecosystem processes as well as for lake management.

Rigid supersymmetry with boundaries

Energy Technology Data Exchange (ETDEWEB)

Belyaev, D.V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Van Nieuwenhuizen, P. [State Univ. of New York, Stony Brook, NY (United States). C.N. Yang Inst. for Theoretical Physics

2008-01-15

We construct rigidly supersymmetric bulk-plus-boundary actions, both in x-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended F- or D-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle. (orig.)

Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

Science.gov (United States)

Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

2009-01-01

Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance is best done with a November survey.

Comparative impacts of temperature and trade-offs on egg ecology of north Atlantic pelagic fish species

DEFF Research Database (Denmark)

Tsoukali, Stavroula; MacKenzie, Brian

The early life history stages of fish are considered the most vulnerable and can be strongly affected by environmental variability, leading to population fluctuations. Temperature has a major role on development and mortality rates, with consequences for recruitment and overall stock productivity....... We collated development and survival data from publications on laboratory egg incubation experiments to investigate and compare the development, daily mortality and survival of fish eggs from pelagic species in the north Atlantic at different temperatures, and to investigate whether trade-offs exist...... development and high mortality or slow development and low mortality, resulting in similar survivorship percentages across species. These results quantify physiological effects of temperature on the eggs and are a major factor in yielding a close correspondence between the physiological optimum temperature...

At-sea behavior varies with lunar phase in a nocturnal pelagic seabird, the swallow-tailed gull

Science.gov (United States)

Cruz, Sebastian M.; Hooten, Mevin; Huyvaert, Kathryn P.; Proaño, Carolina B.; Anderson, David J.; Afanasyev, Vsevolod; Wikelski, Martin

2013-01-01

Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM) that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase.

Early life history pelagic exposure profiles of selected commercially important fish species in the Gulf of Alaska

Science.gov (United States)

Doyle, Miriam J.; Mier, Kathryn L.

2016-10-01

A synthesis of nearly four decades of ichthyoplankton survey data from the Gulf of Alaska was undertaken to provide the most comprehensive information available on the early life history ecology of five focal species: Pacific Cod (Gadus macrocephalus), Walleye Pollock (Gadus chalcogrammus), Pacific Ocean Perch (Sebastes alutus), Sablefish (Anoplopoma fimbria), and Arrowtooth Flounder (Atheresthes stomias). This analysis of historical data, along with information from published studies, is presented here in the form of ecological reviews of the species during their planktonic phase. The reviews include descriptions of temporal and spatial patterns of exposure to the environment, and interpretation regarding associated sensitivities to environmental forcing. On a temporal scale, patterns in abundance of eggs and larvae are synthesized that characterize seasonal exposure to the pelagic environment, and interannual variation that is presumed to incorporate responses to long-term environmental forcing. Spatial patterns are synthesized to identify horizontal and vertical extent of egg and larval distributions, delineate areas of primary larval habitat, and illuminate egg and larval drift pathways. The observed patterns are discussed with respect to characterizing species early life history strategies, identifying long-term adaptations to the Gulf of Alaska environment, and associated resilience and vulnerability factors that may modulate early life responses to environmental forcing in this region. For each species, gaps in knowledge are identified and are concerned primarily with the period of transition between the larval and juvenile stage, and feeding habits and ecology across seasons, habitats and sub-intervals of early ontogeny. These early life history reviews advance our ecological understanding of the pelagic phase, and fine-tune our focus for the investigation of potential response mechanisms to environmental forcing at appropriate, species-specific temporal

Authigenic Uranium in Eastern Equatorial Pacific Sediments

Science.gov (United States)

Marcantonio, F.; Lyle, M. W.; Loveley, M. R.; Ibrahim, R.

2014-12-01

Authigenic U concentrations have been used as an indicator of redox state in marine sediments. Soluble U(VI) in porewaters is reduced to insoluble U(IV) under suboxic conditions setting up a diffusion gradient through which U in bottom waters is supplied to reducing sediments. Researchers have used sedimentary redox enrichment of U as a tool to identify past redox changes, which may be caused by changes in organic carbon rain rates and/or bottom water oxygen levels. Differentiating between these two explanations is important, as the former is tied to the use of authigenic U as a paleoproductivity proxy. We examined sediments from 4 sediment cores retrieved from two different localities in the Panama Basin in the eastern equatorial Pacific. Two cores were retrieved from the northern Panama basin at the Cocos Ridge, (4JC at 5° 44.7'N 85° 45.5' W, 1730 m depth; 8JC at 6° 14.0'N 86° 2.6' W, 1993 m depth), and two were retrieved from the south at the Carnegie Ridge, (11JC at 0° 41.6'S 85° 20.0' W, 2452 m depth; 17JC at 0° 10.8'S 85° 52.0' W, 2846 m depth). Using 230Th systematics and seismic profiling at each of the sites, we've identified significant sediment winnowing (4JC and 11JC) and focusing (8JC and 17JC). At all sites, we believe that changes in age-model-derived sand (i.e., >63µm) mass accumulation rates (MAR) best represent changes in rain rates. Glacial rain rates are higher than those in the Holocene by a factor of 2-3 at both sites. Peak Mn levels (>1%), the brown-to-green color transition (which likely represents the oxic/post-oxic boundary), and peak U concentrations all appear in the same order with increasing depth down core. At the Carnegie sites, where MARs are greater than those at the Cocos sites, increases in authigenic U (up to 4 ppm) occur during the mid- to late Holocene at depths of 10-15 cm. At the Cocos sites, increases in authigenic U (up to 12 ppm) occur lower in the sediment column (25-30 cm) during the late glacial. The decrease

The response of the Goddard general circulation model to sea ice boundary conditions

Science.gov (United States)

Herman, G.; Johnson, W. T.

1979-01-01

The effect of variation in the location of Arctic sea ice boundaries on the model's mean monthly climatology was examined. When sea ice boundaries were at their maximum extent the differences resulted in the January-February climatology. Sea level pressure was higher over the Barents Sea, in the Davis Strait, and in the Sea of Okhotsk. Pressure was lower by as much as 8 mb in the North Atlantic between Iceland and the British Isles, and in the Gulf of Alaska. Pressure rises in the eastern subtropical regions of the North Atlantic and North Pacific accompanied pressure falls in the Gulf of Alaska and Icelandic region. Geopotential heights at 500 mb were more than 100 gpm lower in the Bering Sea, and more than 120 gpm lower in the Icelandic region. Zonally averaged temperatures were cooler by 4 deg C below 3800 mb between 50 deg and 70 deg N with little change elsewhere. Zonally averaged geopotentials were lower by as much as 70 gpm in the mid-troposphere between 50/-70 deg N and zonal winds increased by as much as 3 m s in the mid-troposphere between 35/-50 deg N.

On boundary superalgebras

International Nuclear Information System (INIS)

Doikou, Anastasia

2010-01-01

We examine the symmetry breaking of superalgebras due to the presence of appropriate integrable boundary conditions. We investigate the boundary breaking symmetry associated with both reflection algebras and twisted super-Yangians. We extract the generators of the resulting boundary symmetry as well as we provide explicit expressions of the associated Casimir operators.

Fatty acids in six small pelagic fish species and their crustacean prey from the mindanao sea, southern Philippines.

Science.gov (United States)

Metillo, Ephrime Bicoy; Aspiras-Eya, Anna Arlene

2014-08-01

Fatty acids are important in human health and useful in the analysis of the marine food web, however information on tropical pelagic organisms is scarce. Six zooplanktivorous small pelagic fish species (Decapterus kurroides, Decapterus macarellus, Selar crumenophthalmus, Sardinella lemuru, Spratilloides gracilis and Stolephorus insularis) and four of their zooplanktonic crustacean prey [three sergestoid species (Acetes erythraeus, Acetes intermedius and Lucifer penicillifer) and one calanoid copepod (Acartia erythraea)] were collected from the Mindanao Sea, and their fatty acids were profiled. The resulting profiles revealed 17 fatty acids that were specific to certain species and 9 {myristic acid [C14:0], palmitic acid [C16:0], stearic acid [C18:0]; palmitoleic acid [C16:1], oleic acid [C18:1n9c], linoleic acid [C18:2n6c], linolenic acid [C18:3n3], eicosapentaenoic acid (EPA) [C20:5n3] and docosahexaenoic acid (DHA) [C22:6n3]} that were common to all species. Cluster analysis and non-metric multidimensional scaling (NMDS) of fatty acids indicate a high similarity in profiles in all species, but separate fish and zooplankton clusters were obtained. Mackerel species (D. macarellus, D. kurroides and S. crumenophthalmus) had concentrations of total n-3 fatty acids that match those of their Acetes prey. The copepod A. erythraea and the sergestoid L. penicillifer exhibited the lowest values of the EPA:DHA ratio, which was most likely due to their phytoplanktivorous feeding habits, but the occurrence of the highest values of the ratio in Acetes suggests the inclusion of plant detritus in their diet. DHA values appear to affirm the trophic link among copepod, Lucifer, Acetes and mackerel species.

Evolution in the deep sea: biological traits, ecology and phylogenetics of pelagic copepods.

Science.gov (United States)

Laakmann, Silke; Auel, Holger; Kochzius, Marc

2012-11-01

Deep-sea biodiversity has received increasing interest in the last decade, mainly focusing on benthic communities. In contrast, studies of zooplankton in the meso- to bathypelagic zones are relatively scarce. In order to explore evolutionary processes in the pelagic deep sea, the present study focuses on copepods of two clausocalanoid families, Euchaetidae and Aetideidae, which are abundant and species-rich in the deep-sea pelagic realm. Molecular phylogenies based on concatenated-portioned data on 18S, 28S and internal transcribed spacer 2 (ITS2), as well as mitochondrial cytochrome c oxidase subunit I (COI), were examined on 13 species, mainly from Arctic and Antarctic regions, together with species-specific biological traits (i.e. vertical occurrence, feeding behaviour, dietary preferences, energy storage, and reproductive strategy). Relationships were resolved on genus, species and even sub-species levels, the latter two established by COI with maximum average genetic distances ranging from ≤5.3% at the intra-specific, and 20.6% at the inter-specific level. There is no resolution at a family level, emphasising the state of Euchaetidae and Aetideidae as sister families and suggesting a fast radiation of these lineages, a hypothesis which is further supported by biological parameters. Euchaetidae were similar in lipid-specific energy storage, reproductive strategy, as well as feeding behaviour and dietary preference. In contrast, Aetideidae were more diverse, comprising a variety of characteristics ranging from similar adaptations within Paraeuchaeta, to genera consisting of species with completely different reproductive and feeding ecologies. Reproductive strategies were generally similar within each aetideid genus, but differed between genera. Closely related species (congeners), which were similar in the aforementioned biological and ecological traits, generally occurred in different depth layers, suggesting that vertical partitioning of the water column

Novel Pelagic Iron-Oxidizing Zetaproteobacteria from the Chesapeake Bay Oxic–Anoxic Transition Zone

Science.gov (United States)

Chiu, Beverly K.; Kato, Shingo; McAllister, Sean M.; Field, Erin K.; Chan, Clara S.

2017-01-01

Chemolithotrophic iron-oxidizing bacteria (FeOB) could theoretically inhabit any environment where Fe(II) and O2 (or nitrate) coexist. Until recently, marine Fe-oxidizing Zetaproteobacteria had primarily been observed in benthic and subsurface settings, but not redox-stratified water columns. This may be due to the challenges that a pelagic lifestyle would pose for Zetaproteobacteria, given low Fe(II) concentrations in modern marine waters and the possibility that Fe oxyhydroxide biominerals could cause cells to sink. However, we recently cultivated Zetaproteobacteria from the Chesapeake Bay oxic–anoxic transition zone, suggesting that they can survive and contribute to biogeochemical cycling in a stratified estuary. Here we describe the isolation, characterization, and genomes of two new species, Mariprofundus aestuarium CP-5 and Mariprofundus ferrinatatus CP-8, which are the first Zetaproteobacteria isolates from a pelagic environment. We looked for adaptations enabling strains CP-5 and CP-8 to overcome the challenges of living in a low Fe redoxcline with frequent O2 fluctuations due to tidal mixing. We found that the CP strains produce distinctive dreadlock-like Fe oxyhydroxide structures that are easily shed, which would help cells maintain suspension in the water column. These oxides are by-products of Fe(II) oxidation, likely catalyzed by the putative Fe(II) oxidase encoded by the cyc2 gene, present in both CP-5 and CP-8 genomes; the consistent presence of cyc2 in all microaerophilic FeOB and other FeOB genomes supports its putative role in Fe(II) oxidation. The CP strains also have two gene clusters associated with biofilm formation (Wsp system and the Widespread Colonization Island) that are absent or rare in other Zetaproteobacteria. We propose that biofilm formation enables the CP strains to attach to FeS particles and form flocs, an advantageous strategy for scavenging Fe(II) and developing low [O2] microenvironments within more oxygenated waters

Grain boundary structure and properties

International Nuclear Information System (INIS)

Balluffi, R.W.

1979-01-01

An attempt is made to distinguish those fundamental aspects of grain boundaries which should be relevant to the problem of the time dependent fracture of high temperature structural materials. These include the basic phenomena which are thought to be associated with cavitation and cracking at grain boundaries during service and with the more general microstructural changes which occur during both processing and service. A very brief discussion of the current state of our knowledge of these fundamentals is given. Included are the following: (1) structure of ideal perfect boundaries; (2) defect structure of grain boundaries; (3) diffusion at grain boundaries; (4) grain boundaries as sources/sinks for point defects; (5) grain boundary migration; (6) dislocation phenomena at grain boundaries; (7) atomic bonding and cohesion at grain boundaries; (8) non-equilibrium properties of grain boundaries; and (9) techniques for studying grain boundaries

Landslides and megathrust splay faults captured by the late Holocene sediment record of eastern Prince William Sound, Alaska

Science.gov (United States)

Finn, S.P.; Liberty, Lee M.; Haeussler, Peter J.; Pratt, Thomas L.

2015-01-01

We present new marine seismic‐reflection profiles and bathymetric maps to characterize Holocene depositional patterns, submarine landslides, and active faults beneath eastern and central Prince William Sound (PWS), Alaska, which is the eastern rupture patch of the 1964 Mw 9.2 earthquake. We show evidence that submarine landslides, many of which are likely earthquake triggered, repeatedly released along the southern margin of Orca Bay in eastern PWS. We document motion on reverse faults during the 1964 Great Alaska earthquake and estimate late Holocene slip rates for these growth faults, which splay from the subduction zone megathrust. Regional bathymetric lineations help define the faults that extend 40–70 km in length, some of which show slip rates as great as 3.75  mm/yr. We infer that faults mapped below eastern PWS connect to faults mapped beneath central PWS and possibly onto the Alaska mainland via an en echelon style of faulting. Moderate (Mw>4) upper‐plate earthquakes since 1964 give rise to the possibility that these faults may rupture independently to potentially generate Mw 7–8 earthquakes, and that these earthquakes could damage local infrastructure from ground shaking. Submarine landslides, regardless of the source of initiation, could generate local tsunamis to produce large run‐ups along nearby shorelines. In a more general sense, the PWS area shows that faults that splay from the underlying plate boundary present proximal, perhaps independent seismic sources within the accretionary prism, creating a broad zone of potential surface rupture that can extend inland 150 km or more from subduction zone trenches.

Emerging boundaries

DEFF Research Database (Denmark)

Løvschal, Mette

2014-01-01

of temporal and material variables have been applied as a means of exploring the processes leading to their socioconceptual anchorage. The outcome of this analysis is a series of interrelated, generative boundary principles, including boundaries as markers, articulations, process-related devices, and fixation...

Changing Boundaries

DEFF Research Database (Denmark)

Brodkin, Evelyn; Larsen, Flemming

2013-01-01

project that is altering the boundary between the democratic welfare state and the market economy. We see workfare policies as boundary-changing with potentially profound implications both for individuals disadvantaged by market arrangements and for societies seeking to grapple with the increasing...

The great triangular seismic region in eastern Asia: Thoughts on its dynamic context

Directory of Open Access Journals (Sweden)

Xianglin Gao

2011-01-01

Full Text Available A huge triangle-shaped tectonic region in eastern Asia plays host to numerous major earthquakes. The three boundaries of this region, which contains plateaus, mountains, and intermountain basins, are roughly the Himalayan arc, the Tianshan-Baikal, and longitude line ∼105°E. Within this triangular region, tectonism is intense and major deformation occurs both between crustal blocks and within most of them. Outside of this region, rigid blocks move as a whole with relatively few major earthquakes and relatively weak Cenozoic deformation. On a large tectonic scale, the presence of this broad region of intraplate deformation results from dynamic interactions between the Indian, Philippine Sea-West Pacific, and Eurasian plates, as well as the influence of deep-level mantle flow. The Indian subcontinent, which continues to move northwards at ∼40 mm/a since its collision with Eurasia, has plunged beneath Tibet, resulting in various movements and deformations along the Himalayan arc that diffuse over a long distance into the hinterland of Asia. The northward crustal escape of Asia from the Himalayan collisional zone turns eastwards and southeastwards along 95°–100°E longitude and defines the eastern Himalayan syntaxis. At the western Himalayan syntaxis, the Pamirs continue to move into central Asia, leading to crustal deformation and earthquakes that are largely accommodated by old EW or NW trending faults in the bordering areas between China, Mongolia, and Russia, and are restricted by the stable landmass northwest of the Tianshan-Altai-Baikal region. The subduction of the Philippine and Pacific plates under the Eurasian continent has generated a very long and narrow seismic zone along trenches and island arcs in the marginal seas while imposing only slight horizontal compression on the Asian continent that does not impede the eastward motion of eastern Asia. In the third dimension, there may be southeastward deep mantle flow beneath most of

Gas in Eastern Europe

International Nuclear Information System (INIS)

Anon.

1994-01-01

West European gas companies have long recognised the potential for lucrative business within eastern Europe. But they recognise that the region's integration into the west European system will be far from straightforward, with deals between east European gas companies and their western counterparts invariably containing financial mechanisms, such as barter trade, that are designed to cope with the easterners' shortage of hard currency. (author)

Spatial and temporal variation in artisanal catches of dolphinfish Coryphaena hippurus off north-eastern Brazil.

Science.gov (United States)

Nóbrega, M F; Kinas, P G; Lessa, R; Ferrandis, E

2015-02-01

The sampling of fish from the artisanal fleet operating with surface lines off north-eastern Brazil was carried out between 1998 and 2000. Generalized linear models (GLMs) were used to standardize mean abundance indices using catch and fishing effort data on dolphinfish Coryphaena hippurus and to identify abundance trends in time and space, using 1215 surface line deployments. A standard relative abundance index (catch per unit effort, CPUE) was estimated for the most frequent vessels used in the sets, employing factors and coefficients generated in the GLMs. According to the models, C. hippurus catches are affected by the operating characteristics and power of different fishing vessels. These differences highlight the need for standardization of catch and effort data for artisanal fisheries. The highest mean abundance values for C. hippurus were off the state of Rio Grande do Norte, with an increasing tendency in areas with greater depths and more distant from the coast, reaching maximal values in areas whose depths range from 200 to 500 m. The highest mean abundance values occurred between April and June. The higher estimated abundance of C. hippurus in this period off the state of Rio Grande do Norte and within the 200-500 m depth range may be related to a migration pattern of food sources, as its main prey, the flying fish Hirundichthys affinis, uses floating algae as refuge and to deposit its pelagic eggs. © 2015 The Fisheries Society of the British Isles.

Eastern Sources of Invitational Education.

Science.gov (United States)

Ryback, David

1993-01-01

Presents historical perspective suggesting that invitational theory shares many beliefs with ancient Eastern philosophies. Submits that teachers and other educators who embrace the invitational perspective may benefit from an understanding of Eastern principles. Briefly describes Buddhism, Confucianism, Taoism, Zen Buddhism, and their relevance to…

The impact of gyre dynamics on the mid-depth salinity signature of the eastern North Atlantic

Science.gov (United States)

Burkholder, K. C.; Lozier, M. S.

2009-04-01

The Mediterranean Overflow Water (MOW) is widely recognized for its role in establishing the mid-depth salinity signature of the subtropical North Atlantic. However, recent work has revealed an intermittent impact of MOW on the salinity signature of the eastern subpolar basin. This impact results from a temporally variable penetration of the northward flowing branch of the MOW past Porcupine Bank into the eastern subpolar basin. It has been shown that the salinity signature of the eastern subpolar basin, in particular the Rockall Trough, varies with the state of the North Atlantic Oscillation (NAO): during persistent periods of strong winds (high NAO index), when the subpolar front moves eastward, waters in the subpolar gyre block the northward flowing MOW, preventing its entry into the subpolar gyre. Conversely, during persistent periods of weak winds (low NAO index), the front moves westward, allowing MOW to penetrate north of Porcupine Bank and into the subpolar gyre. Here, we investigate the manner in which the spatial and temporal variability in the northward penetration of the MOW and the position of the eastern limb of the subpolar front affect the mid-depth property fields not only in the subpolar gyre, but in the subtropical gyre as well. Using approximately 55 years of historical hydrographic data and output from the 1/12° FLAME model, we analyze the temporal variability of salinity along the eastern boundary and compare this variability to the position of the subpolar front in both the observational record and the FLAME model. We conclude that when the zonal position of the subpolar front moves relatively far offshore and the MOW is able to penetrate to the north, high salinity anomalies are observed at high latitudes and low salinity anomalies are observed at low latitudes. Conversely, when the frontal position shifts to the east, the MOW (and thus, the high salinity signature) is blocked, resulting in a drop in salinity anomalies at high latitudes

Prevalence of blood parasites in eastern versus Western house finches: are eastern birds resistant to infection?

Science.gov (United States)

Davis, Andrew K; Hood, Wendy R; Hill, Geoffrey E

2013-09-01

The rapid spread of the bacterial disease, Mycoplasma gallisepticum (MG), throughout the introduced range of house finches (Carpodacus mexicanus) in eastern North America, compared to its slower spread through the native western range, has puzzled researchers and highlights the need to understand the relative differences in health state of finches from both populations. We conducted a light-microscope survey of hemoparasites in populations of finches from Arizona (within the western range) and from Alabama (within the eastern range), and compared our estimates of prevalence to published reports from house finches sampled in both ranges. Of the 33 Arizona birds examined, we recorded hematozoan infections in 16 (48.5%) individuals, compared to 1 infected Alabama bird out of 30 birds examined (3.3%). Based on independent surveys of seven western North American and five eastern North American populations of house finches the average prevalence of blood parasites in western populations is 38.8% (±17.9 SD), while the average prevalence within the eastern range is only 5.9% (±6.1 SD). The average rate of infection among all songbirds sampled in the east is 34.2% (±4.8 SD). Thus, our surveys of wild birds as well as previously published observations point to eastern house finches having a much lower prevalence of blood parasite infections than their western counterparts. Combined with the fact that eastern finches also tend to have lower rates of avian pox infections than do western birds (based on a literature review), these observations suggest that eastern birds have either strong resistance to these infections or high susceptibility and associated mortality.

Collaboration in Healthcare Through Boundary Work and Boundary Objects

DEFF Research Database (Denmark)

Meier, Ninna

2015-01-01

This article contributes to our understanding of how boundary work is practiced in healthcare settings. Previous studies have shown how boundaries are constantly changing, multiple, and co-existing, and can also be relatively stable cognitive and social distinctions between individuals and groups...

Circulation, eddies, oxygen, and nutrient changes in the eastern tropical South Pacific Ocean

Science.gov (United States)

Czeschel, R.; Stramma, L.; Weller, R. A.; Fischer, T.

2015-06-01

A large subsurface oxygen deficiency zone is located in the eastern tropical South Pacific Ocean (ETSP). The large-scale circulation in the eastern equatorial Pacific and off the coast of Peru in November/December 2012 shows the influence of the equatorial current system, the eastern boundary currents, and the northern reaches of the subtropical gyre. In November 2012 the equatorial undercurrent (EUC) is centered at 250 m depth, deeper than in earlier observations. In December 2012, the equatorial water is transported southeastward near the shelf in the Peru-Chile undercurrent (PCUC) with a mean transport of 1.4 Sv. In the oxygen minimum zone (OMZ), the flow is overlaid with strong eddy activity on the poleward side of the OMZ. Floats with parking depth at 400 m show fast westward flow in the mid-depth equatorial channel and sluggish flow in the OMZ. Floats with oxygen sensors clearly show the passage of eddies with oxygen anomalies. The long-term float observations in the upper ocean lead to a net community production estimate at about 18° S of up to 16.7 mmol C m-3 yr-1 extrapolated to an annual rate and 7.7 mmol C m-3 yr-1 for the time period below the mixed layer. Oxygen differences between repeated ship sections are influenced by the Interdecadal Pacific Oscillation (IPO), by the phase of El Niño, by seasonal changes, and by eddies, and hence have to be interpreted with care. At and south of the Equator the decrease in oxygen in the upper ocean since 1976 is related to an increase in nitrate, phosphate, and in part silicate.

Optimal boundary control and boundary stabilization of hyperbolic systems

CERN Document Server

Gugat, Martin

2015-01-01

This brief considers recent results on optimal control and stabilization of systems governed by hyperbolic partial differential equations, specifically those in which the control action takes place at the boundary.  The wave equation is used as a typical example of a linear system, through which the author explores initial boundary value problems, concepts of exact controllability, optimal exact control, and boundary stabilization.  Nonlinear systems are also covered, with the Korteweg-de Vries and Burgers Equations serving as standard examples.  To keep the presentation as accessible as possible, the author uses the case of a system with a state that is defined on a finite space interval, so that there are only two boundary points where the system can be controlled.  Graduate and post-graduate students as well as researchers in the field will find this to be an accessible introduction to problems of optimal control and stabilization.

Identifying Fault Connections of the Southern Pacific-North American Plate Boundary Using Triggered Slip and Crustal Velocities

Science.gov (United States)

Donnellan, A.; Grant Ludwig, L.; Rundle, J. B.; Parker, J. W.; Granat, R.; Heflin, M. B.; Pierce, M. E.; Wang, J.; Gunson, M.; Lyzenga, G. A.

2017-12-01

The 2010 M7.2 El Mayor - Cucapah earthquake caused extensive triggering of slip on faults proximal to the Salton Trough in southern California. Triggered slip and postseismic motions that have continued for over five years following the earthquake highlight connections between the El Mayor - Cucapah rupture and the network of faults that branch out along the southern Pacific - North American Plate Boundary. Coseismic triggering follows a network of conjugate faults from the northern end of the rupture to the Coachella segment of the southernmost San Andreas fault. Larger aftershocks and postseismic motions favor connections to the San Jacinto and Elsinore faults further west. The 2012 Brawley Swarm can be considered part of the branching on the Imperial Valley or east side of the plate boundary. Cluster analysis of long-term GPS velocities using Lloyds Algorithm, identifies bifurcation of the Pacific - North American plate boundary; The San Jacinto fault joins with the southern San Andreas fault, and the Salton Trough and Coachella segment of the San Andreas fault join with the Eastern California Shear Zone. The clustering analysis does not identify throughgoing deformation connecting the Coachella segment of the San Andreas fault with the rest of the San Andreas fault system through the San Gorgonio Pass. This observation is consistent with triggered slip from both the 1992 Landers and 2010 El Mayor - Cucapah earthquakes that follows the plate boundary bifurcation and with paleoseismic evidence of smaller earthquakes in the San Gorgonio Pass.

Global diversity and biogeography of deep-sea pelagic prokaryotes

KAUST Repository

Salazar, Guillem

2015-08-07

The deep-sea is the largest biome of the biosphere, and contains more than half of the whole ocean\\'s microbes. Uncovering their general patterns of diversity and community structure at a global scale remains a great challenge, as only fragmentary information of deep-sea microbial diversity exists based on regional-scale studies. Here we report the first globally comprehensive survey of the prokaryotic communities inhabiting the bathypelagic ocean using high-throughput sequencing of the 16S rRNA gene. This work identifies the dominant prokaryotes in the pelagic deep ocean and reveals that 50% of the operational taxonomic units (OTUs) belong to previously unknown prokaryotic taxa, most of which are rare and appear in just a few samples. We show that whereas the local richness of communities is comparable to that observed in previous regional studies, the global pool of prokaryotic taxa detected is modest (∼3600 OTUs), as a high proportion of OTUs are shared among samples. The water masses appear to act as clear drivers of the geographical distribution of both particle-attached and free-living prokaryotes. In addition, we show that the deep-oceanic basins in which the bathypelagic realm is divided contain different particle-attached (but not free-living) microbial communities. The combination of the aging of the water masses and a lack of complete dispersal are identified as the main drivers for this biogeographical pattern. All together, we identify the potential of the deep ocean as a reservoir of still unknown biological diversity with a higher degree of spatial complexity than hitherto considered.

Global diversity and biogeography of deep-sea pelagic prokaryotes

KAUST Repository

Salazar, Guillem; Cornejo-Castillo, Francisco M.; Bení tez-Barrios, Veró nica; Fraile-Nuez, Eugenio; Á lvarez-Salgado, X. Antó n; Duarte, Carlos M.; Gasol, Josep M.; Acinas, Silvia G.

2015-01-01

The deep-sea is the largest biome of the biosphere, and contains more than half of the whole ocean's microbes. Uncovering their general patterns of diversity and community structure at a global scale remains a great challenge, as only fragmentary information of deep-sea microbial diversity exists based on regional-scale studies. Here we report the first globally comprehensive survey of the prokaryotic communities inhabiting the bathypelagic ocean using high-throughput sequencing of the 16S rRNA gene. This work identifies the dominant prokaryotes in the pelagic deep ocean and reveals that 50% of the operational taxonomic units (OTUs) belong to previously unknown prokaryotic taxa, most of which are rare and appear in just a few samples. We show that whereas the local richness of communities is comparable to that observed in previous regional studies, the global pool of prokaryotic taxa detected is modest (∼3600 OTUs), as a high proportion of OTUs are shared among samples. The water masses appear to act as clear drivers of the geographical distribution of both particle-attached and free-living prokaryotes. In addition, we show that the deep-oceanic basins in which the bathypelagic realm is divided contain different particle-attached (but not free-living) microbial communities. The combination of the aging of the water masses and a lack of complete dispersal are identified as the main drivers for this biogeographical pattern. All together, we identify the potential of the deep ocean as a reservoir of still unknown biological diversity with a higher degree of spatial complexity than hitherto considered.

Regional Development of Eastern Slovakia

Directory of Open Access Journals (Sweden)

Monika Hergezelová

2017-08-01

Full Text Available Purpose and Originality: The aim of the work is to provide an overview of regional development in Eastern Slovakia, where are Košice and Prešov Region. The originality of the work lies in the work of enriching the SWOT analysis from the author Eve Rajčáková, which is given in the book deals with the issue of Regional development and regional policy of the European Union and Slovakia. Research question: The conditions of life of people in eastern Slovakia. Method: For writing this contribution will be used method of analysis and statistics. Knowledge on this subject have been looking on the internet and in books and sources of information publicly available. Using the data collected, we dealt with the issue of regional development in the Košice and Prešov regions. Results: The topic was the beginning focused on the overall characteristics of eastern Slovakia. Furthermore, we are at work we dealt with social and economic phenomena in both regions of eastern Slovakia. We focused on GDP, unemployment and tourism, which is in the region is widespread. Society: It is well known that there are obviously different living conditions in eastern Slovakia as in other parts of Slovakia. People are forced to, mainly because of employment, leave their region to move or commute to work to the west. The paper point out the right of this negative phenomenon that is quite visible - high unemployment. Limitations: The limits of work are limited by problems of regional development in eastern Slovakia, mainly focusing on economic and social phenomena in the society.

A boundary integral equation for boundary element applications in multigroup neutron diffusion theory

International Nuclear Information System (INIS)

Ozgener, B.

1998-01-01

A boundary integral equation (BIE) is developed for the application of the boundary element method to the multigroup neutron diffusion equations. The developed BIE contains no explicit scattering term; the scattering effects are taken into account by redefining the unknowns. Boundary elements of the linear and constant variety are utilised for validation of the developed boundary integral formulation

The Eastern Partnership

DEFF Research Database (Denmark)

Nielsen, Kristian L.; Vilson, Maili

2014-01-01

When the EU launched the Eastern Partnership (EaP) in 2009, it did so with much rhetoric about projecting its soft power into Eastern Europe. Yet today, the EU's soft power project seems to have stalled, with developments in the region being less than favourable. This article argues that the EaP...... essentially replicated the main weaknesses of the European Neighbourhood Policy, by offering too little incentive and support to the partners, rendering both conditionality and soft power ineffective as tools for milieu shaping. In promoting the EaP as a policy of soft power, the EU has once again forgotten...

Pelagic tar, dissolved/dispersed petroleum hydrocarbons and plastic distribution in the Cretan Sea, Greece

Energy Technology Data Exchange (ETDEWEB)

Kornilios, S.; Drakopoulos, P.G.; Dounas, C. [Institute of Marine Biology of Crete, Iraklio (Greece). Environmental Dept.

1998-12-01

During the first cruise of R/V `Philia` in July 1997 within the framework of the TALOS programme supported by the Greek Ministry of Physical Planning and Public Works, the sampling of floating tar, litter and sea water for dissolved/dispersed petroleum hydrocarbons (DDPH) was carried out in the Cretan Sea. Analysis of these data has allowed a first assessment of the status of floating marine pollution in the region. DDPH measurements showed a mean concentration of 0.145 {mu}g/l of chrysene equivalents (n = 24). Tar and plastics concentrations were in the range of 1-4280 and 0-1160 {mu}g/m{sup 2}, respectively. Mean pelagic tar concentration was 318 {mu}g/m{sup 2}, more than two times higher than what was reported for the area in previous studies. Based on in situ hydrographic observations there is strong evidence that most of the floating tar enters the Cretan Sea through the Ionian Sea. (author)

Pelagic tar, dissolved/dispersed petroleum hydrocarbons and plastic distribution in the Cretan Sea, Greece

Energy Technology Data Exchange (ETDEWEB)

Kornilios, S.; Drakopoulos, P.G.; Dounas, C. [Institute of Marine Biology of Crete, Iraklio (Greece). Environmental Dept.

1998-12-01

During the first cruise of R/V 'Philia' in July 1997 within the framework of the TALOS programme supported by the Greek Ministry of Physical Planning and Public Works, the sampling of floating tar, litter and sea water for dissolved/dispersed petroleum hydrocarbons (DDPH) was carried out in the Cretan Sea. Analysis of these data has allowed a first assessment of the status of floating marine pollution in the region. DDPH measurements showed a mean concentration of 0.145 {mu}g/l of chrysene equivalents (n = 24). Tar and plastics concentrations were in the range of 1-4280 and 0-1160 {mu}g/m{sup 2}, respectively. Mean pelagic tar concentration was 318 {mu}g/m{sup 2}, more than two times higher than what was reported for the area in previous studies. Based on in situ hydrographic observations there is strong evidence that most of the floating tar enters the Cretan Sea through the Ionian Sea. (author)

Predictive ethoinformatics reveals the complex migratory behaviour of a pelagic seabird, the Manx Shearwater

Science.gov (United States)

Freeman, Robin; Dean, Ben; Kirk, Holly; Leonard, Kerry; Phillips, Richard A.; Perrins, Chris M.; Guilford, Tim

2013-01-01

Understanding the behaviour of animals in the wild is fundamental to conservation efforts. Advances in bio-logging technologies have offered insights into the behaviour of animals during foraging, migration and social interaction. However, broader application of these systems has been limited by device mass, cost and longevity. Here, we use information from multiple logger types to predict individual behaviour in a highly pelagic, migratory seabird, the Manx Shearwater (Puffinus puffinus). Using behavioural states resolved from GPS tracking of foraging during the breeding season, we demonstrate that individual behaviours can be accurately predicted during multi-year migrations from low cost, lightweight, salt-water immersion devices. This reveals a complex pattern of migratory stopovers: some involving high proportions of foraging, and others of rest behaviour. We use this technique to examine three consecutive years of global migrations, revealing the prominence of foraging behaviour during migration and the importance of highly productive waters during migratory stopover. PMID:23635496

Pelagic tar, dissolved/dispersed petroleum hydrocarbons and plastic distribution in the Cretan Sea, Greece

International Nuclear Information System (INIS)

Kornilios, S.; Drakopoulos, P.G.; Dounas, C.

1998-01-01

During the first cruise of R/V 'Philia' in July 1997 within the framework of the TALOS programme supported by the Greek Ministry of Physical Planning and Public Works, the sampling of floating tar, litter and sea water for dissolved/dispersed petroleum hydrocarbons (DDPH) was carried out in the Cretan Sea. Analysis of these data has allowed a first assessment of the status of floating marine pollution in the region. DDPH measurements showed a mean concentration of 0.145 μg/l of chrysene equivalents (n = 24). Tar and plastics concentrations were in the range of 1-4280 and 0-1160 μg/m 2 , respectively. Mean pelagic tar concentration was 318 μg/m 2 , more than two times higher than what was reported for the area in previous studies. Based on in situ hydrographic observations there is strong evidence that most of the floating tar enters the Cretan Sea through the Ionian Sea. (author)

Heterogeneity of the organic matter in the Guayuta group, Eastern Venezuelan Basin

Energy Technology Data Exchange (ETDEWEB)

Alberdi, M.; Gallango, O.; Ruggiero, A.; Jordan, N. (Intevep, S.A., Caracas (Venezuela)); Lefargue, E. (I.F.P., Rueil Malmaison (France))

1993-02-01

The purpose of this study is to evaluate the organic matter heterogeneities in the Guayuta Group as a principal hydrocarbon source rock in the Eastern Venezuelan Basin. In order to do this, thirteen wells and five work stations on outcrops of the Interior Mountain Belt were analyzed to study the regional and vertical variations in the geochemical characteristics of the organic matter. It is possible to detect significant differences in quality and quantity of the organic matter which could corroborate the regional development of two organic facies from North to South in the Maturin Subbasin. The northern organic facies show excellent characteristics as source rock. The study of vertical distribution of organic matter was carried out in a well of northern part of the Monagas state, which represents the southern organic facies. It shows an irregular input of continental organic matter, thermally immature. Besides the organic matter content was low (around 1.5%) without depth tendencies. These sediments are clastic and bioclastic in contrast with carbonates and pelagic shales of the Guayuta Group in the Interior Mountain Belt. The outcrop samples studied show a high total organic content (2-6%) despite the high maturity determined on kerogen. The systematic study of this geochemical parameter show pseudocyclic relationships with a general tendency to increase toward the bottom of the section. V, Ni, and S determinations could indicate that anoxic conditions were developing toward the North where the marine organic matter was sedimenting. The results of this study are in agreement with paleogeographic model of sedimentation during middle and late Cretaceous, with sources of sediments from South and a progressive depth of the basin toward the North.

At-sea behavior varies with lunar phase in a nocturnal pelagic seabird, the swallow-tailed gull.

Directory of Open Access Journals (Sweden)

Sebastian M Cruz

Full Text Available Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase.

Millimeter-sized marine plastics: a new pelagic habitat for microorganisms and invertebrates.

Directory of Open Access Journals (Sweden)

Julia Reisser

Full Text Available Millimeter-sized plastics are abundant in most marine surface waters, and known to carry fouling organisms that potentially play key roles in the fate and ecological impacts of plastic pollution. In this study we used scanning electron microscopy to characterize biodiversity of organisms on the surface of 68 small floating plastics (length range = 1.7-24.3 mm, median = 3.2 mm from Australia-wide coastal and oceanic, tropical to temperate sample collections. Diatoms were the most diverse group of plastic colonizers, represented by 14 genera. We also recorded 'epiplastic' coccolithophores (7 genera, bryozoans, barnacles (Lepas spp., a dinoflagellate (Ceratium, an isopod (Asellota, a marine worm, marine insect eggs (Halobates sp., as well as rounded, elongated, and spiral cells putatively identified as bacteria, cyanobacteria, and fungi. Furthermore, we observed a variety of plastic surface microtextures, including pits and grooves conforming to the shape of microorganisms, suggesting that biota may play an important role in plastic degradation. This study highlights how anthropogenic millimeter-sized polymers have created a new pelagic habitat for microorganisms and invertebrates. The ecological ramifications of this phenomenon for marine organism dispersal, ocean productivity, and biotransfer of plastic-associated pollutants, remains to be elucidated.

Study on resources and environmental data integration towards data warehouse construction covering trans-boundary area of China, Russia and Mongolia

Science.gov (United States)

Wang, J.; Song, J.; Gao, M.; Zhu, L.

2014-02-01

The trans-boundary area between Northern China, Mongolia and eastern Siberia of Russia is a continuous geographical area located in north eastern Asia. Many common issues in this region need to be addressed based on a uniform resources and environmental data warehouse. Based on the practice of joint scientific expedition, the paper presented a data integration solution including 3 steps, i.e., data collection standards and specifications making, data reorganization and process, data warehouse design and development. A series of data collection standards and specifications were drawn up firstly covering more than 10 domains. According to the uniform standard, 20 resources and environmental survey databases in regional scale, and 11 in-situ observation databases were reorganized and integrated. North East Asia Resources and Environmental Data Warehouse was designed, which included 4 layers, i.e., resources layer, core business logic layer, internet interoperation layer, and web portal layer. The data warehouse prototype was developed and deployed initially. All the integrated data in this area can be accessed online.

Study on resources and environmental data integration towards data warehouse construction covering trans-boundary area of China, Russia and Mongolia

International Nuclear Information System (INIS)

Wang, J; Song, J; Gao, M; Zhu, L

2014-01-01

The trans-boundary area between Northern China, Mongolia and eastern Siberia of Russia is a continuous geographical area located in north eastern Asia. Many common issues in this region need to be addressed based on a uniform resources and environmental data warehouse. Based on the practice of joint scientific expedition, the paper presented a data integration solution including 3 steps, i.e., data collection standards and specifications making, data reorganization and process, data warehouse design and development. A series of data collection standards and specifications were drawn up firstly covering more than 10 domains. According to the uniform standard, 20 resources and environmental survey databases in regional scale, and 11 in-situ observation databases were reorganized and integrated. North East Asia Resources and Environmental Data Warehouse was designed, which included 4 layers, i.e., resources layer, core business logic layer, internet interoperation layer, and web portal layer. The data warehouse prototype was developed and deployed initially. All the integrated data in this area can be accessed online

DYNAMIC SURFACE BOUNDARY-CONDITIONS - A SIMPLE BOUNDARY MODEL FOR MOLECULAR-DYNAMICS SIMULATIONS

NARCIS (Netherlands)

JUFFER, AH; BERENDSEN, HJC

1993-01-01

A simple model for the treatment of boundaries in molecular dynamics simulations is presented. The method involves the positioning of boundary atoms on a surface that surrounds a system of interest. The boundary atoms interact with the inner region and represent the effect of atoms outside the

Assessing the Health of Puget Sound's Pelagic Food Web at Multiple Trophic Levels

Science.gov (United States)

Rhodes, L. D.; Greene, C. M.; Rice, C. A.; Hall, J. E.; Baxter, A. E.; Naman, S. M.; Chamberlin, J.

2012-12-01

Puget Sound is an estuarine fjord in the northwestern United State surrounded by variable upland uses, ranging from industrial and urban to agricultural to forested lands. The quality of Puget Sound's ecosystem is under scrutiny because of the biological resources that depend on its function. In 2011, we undertook a study of the Sound's pelagic food web that measured water quality, microbial parameters, and abundance of higher trophic levels including gelatinous zooplankton, forage fish, and salmon. More than 75 sites spanning the latitudinal expanse of Puget Sound and the range of developed and agricultural land uses were sampled monthly from April to October. Strong relationships between water quality and microbial parameters suggest that microbes may modulate water quality indicators, such as dissolved inorganic nitrogen and pH, and that land use may be an influential factor. Basins within Puget Sound exhibit distinct biological profiles at the microbial and macrobiotic levels, emphasizing that Puget Sound is not a homogenous water body and suggesting that informative food web indicators may vary across the basins.

Stratification of TAD boundaries reveals preferential insulation of super-enhancers by strong boundaries.

Science.gov (United States)

Gong, Yixiao; Lazaris, Charalampos; Sakellaropoulos, Theodore; Lozano, Aurelie; Kambadur, Prabhanjan; Ntziachristos, Panagiotis; Aifantis, Iannis; Tsirigos, Aristotelis

2018-02-07

The metazoan genome is compartmentalized in areas of highly interacting chromatin known as topologically associating domains (TADs). TADs are demarcated by boundaries mostly conserved across cell types and even across species. However, a genome-wide characterization of TAD boundary strength in mammals is still lacking. In this study, we first use fused two-dimensional lasso as a machine learning method to improve Hi-C contact matrix reproducibility, and, subsequently, we categorize TAD boundaries based on their insulation score. We demonstrate that higher TAD boundary insulation scores are associated with elevated CTCF levels and that they may differ across cell types. Intriguingly, we observe that super-enhancers are preferentially insulated by strong boundaries. Furthermore, we demonstrate that strong TAD boundaries and super-enhancer elements are frequently co-duplicated in cancer patients. Taken together, our findings suggest that super-enhancers insulated by strong TAD boundaries may be exploited, as a functional unit, by cancer cells to promote oncogenesis.

Incorporation of inorganic mercury (Hg2+) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: The role of different plankton size fractions and species assemblages

International Nuclear Information System (INIS)

Soto Cárdenas, Carolina; Diéguez, Maria C.; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P.

2014-01-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg 2+ ) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg 2+ by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope 197 Hg 2+ . Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg 2+ in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg 2+ in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg 2+ by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg 2+ observed in all the plankton fractions. - Highlights: • Hg 2+ incorporation in lake plankton fractions was studied using the isotope 197 Hg 2+ . • Hg 2+ incorporation was assessed using three different

A two-dimensional embedded-boundary method for convection problems with moving boundaries

NARCIS (Netherlands)

Y.J. Hassen (Yunus); B. Koren (Barry)

2010-01-01

htmlabstractIn this work, a two-dimensional embedded-boundary algorithm for convection problems is presented. A moving body of arbitrary boundary shape is immersed in a Cartesian finite-volume grid, which is fixed in space. The boundary surface is reconstructed in such a way that only certain fluxes

African boundary politics: a case of Ethiopian-Eritrean boundary ...

African Journals Online (AJOL)

This paper examined the boundary discord between Ethiopia and Eritrea over the region around Badme which started as a result of artificial boundaries created by the Italian imperialists. The study depicts the evolution of Italian colonialism in Ethiopia between 1936 and 1941. It exposes the differentials existing between the ...

Making Boundaries Great Again: Essentialism and Support for Boundary-Enhancing Initiatives.

Science.gov (United States)

Roberts, Steven O; Ho, Arnold K; Rhodes, Marjorie; Gelman, Susan A

2017-12-01

Psychological essentialism entails a focus on category boundaries (e.g., categorizing people as men or women) and an increase in the conceptual distance between those boundaries (e.g., accentuating the differences between men and women). Across eight studies, we demonstrate that essentialism additionally entails an increase in support for boundary-enhancing legislation, policies, and social services, and that it does so under conditions that disadvantage social groups, as well as conditions that benefit them. First, individual differences in essentialism were associated with support for legislation mandating that transgender people use restrooms corresponding with their biological sex, and with support for the boundary-enhancing policies of the 2016 then-presumptive Republican presidential nominee (i.e., Donald Trump). Second, essentialism was associated with support for same-gender classrooms designed to promote student learning, as well as support for services designed to benefit LGBTQ (lesbian, gay, bisexual, transgender, queer) individuals. These findings demonstrate the boundary-enhancing implications of essentialism and their social significance.

The Boundary Function Method. Fundamentals

Science.gov (United States)

Kot, V. A.

2017-03-01

The boundary function method is proposed for solving applied problems of mathematical physics in the region defined by a partial differential equation of the general form involving constant or variable coefficients with a Dirichlet, Neumann, or Robin boundary condition. In this method, the desired function is defined by a power polynomial, and a boundary function represented in the form of the desired function or its derivative at one of the boundary points is introduced. Different sequences of boundary equations have been set up with the use of differential operators. Systems of linear algebraic equations constructed on the basis of these sequences allow one to determine the coefficients of a power polynomial. Constitutive equations have been derived for initial boundary-value problems of all the main types. With these equations, an initial boundary-value problem is transformed into the Cauchy problem for the boundary function. The determination of the boundary function by its derivative with respect to the time coordinate completes the solution of the problem.

76 FR 2313 - Atlantic Highly Migratory Species; Bluefin Tuna Bycatch Reduction in the Gulf of Mexico Pelagic...

Science.gov (United States)

2011-01-13

..., 2010, an explosion and subsequent fire damaged the Deepwater Horizon MC252 oil rig, which capsized and... Mediterranean stock. Therefore, management actions taken in the eastern Atlantic and Mediterranean are likely to... have significant effects on the West due to the fact that Eastern plus Mediterranean resource is much...

Flora of the Kap River Reserve, Eastern Cape, South Africa

Directory of Open Access Journals (Sweden)

E. C. Cloete

1999-09-01

Full Text Available A detailed analysis ot the flora of the newly proclaimed Kap River Reserve (600 ha is given. The reserve is adjacent to the Fish River and some 5 km from the Fish River Mouth It consists of a coastal plateau up to 100 m a.s.I. which is steeply dissected by the two rivers that partially form the boundary of the reserve. The flora of the reserve was sampled over a period o f three years and plants were collected in all the vegetation types of grassland, thicket and forest. 488 species were collected with a species to family ratio of 4:4. The majority of the taxa recorded represent the major phytochoria of the region. Nineteen species are endemic to the Eastern Cape, two are classed as vulnerable, five are rare, six are protected and a further seventeen are of uncertain status. The flora of the Kap River has closest affinities to that of the Alexandria Forest.

Grain boundary migration

International Nuclear Information System (INIS)

Dimitrov, O.

1975-01-01

Well-established aspects of grain-boundary migration are first briefly reviewed (influences of driving force, temperature, orientation and foreign atoms). Recent developments of the experimental methods and results are then examined, by considering the various driving of resistive forces acting on grain boundaries. Finally, the evolution in the theoretical models of grain-boundary motion is described, on the one hand for ideally pure metals and, on the other hand, in the presence of solute impurity atoms [fr

Grain Boundary Segregation in Metals

CERN Document Server

Lejcek, Pavel

2010-01-01

Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.

Investigation of the atmospheric boundary layer dynamics during the ESCOMPTE campaign

Science.gov (United States)

Saïd, F.; Brut, A.; Campistron, B.; Cousin, F.

2007-03-01

This paper presents some results about the behavior of the atmospheric boundary layer observed during the ESCOMPTE experiment. This campaign, which took place in south-eastern France during summer 2001, was aimed at improving our understanding of pollution episodes in relation to the dynamics of the lower troposphere. Using a large data set, as well as a simulation from the mesoscale non-hydrostatic model Meso-NH, we describe and analyze the atmospheric boundary layer (ABL) development during two specific meteorological conditions of the second Intensive Observation Period (IOP). The first situation (IOP2a, from 22 June to 23 June) corresponds to moderate, dry and cold northerly winds (end of Mistral event), coupled with a sea-breeze in the lower layer, whereas sea-breeze events with weak southerly winds occurred during the second part of the period (IOP2b, from 24 June to 26 June). In this study, we first focus on the validation of the model outputs with a thorough comparison of the Meso-NH simulations with fields measurements on three days of the IOP: 22 June, 23 June and 25 June. We also investigate the structure of the boundary layer on IOP2a when the Mistral is superimposed on a sea breeze. Then, we describe the spatial and diurnal variability of the ABL depths over the ESCOMPTE domain during the whole IOP. This step is essential if one wants to know the depth of the layer where the pollutants can be diluted or accumulated. Eventually, this study intends to describe the ABL variability in relation to local or mesoscale dynamics and/or induced topographic effects, in order to explain pollution transport processes in the low troposphere.

Investigation of the atmospheric boundary layer dynamics during the ESCOMPTE campaign

Directory of Open Access Journals (Sweden)

F. Saïd

2007-03-01

Full Text Available This paper presents some results about the behavior of the atmospheric boundary layer observed during the ESCOMPTE experiment. This campaign, which took place in south-eastern France during summer 2001, was aimed at improving our understanding of pollution episodes in relation to the dynamics of the lower troposphere. Using a large data set, as well as a simulation from the mesoscale non-hydrostatic model Meso-NH, we describe and analyze the atmospheric boundary layer (ABL development during two specific meteorological conditions of the second Intensive Observation Period (IOP. The first situation (IOP2a, from 22 June to 23 June corresponds to moderate, dry and cold northerly winds (end of Mistral event, coupled with a sea-breeze in the lower layer, whereas sea-breeze events with weak southerly winds occurred during the second part of the period (IOP2b, from 24 June to 26 June.

In this study, we first focus on the validation of the model outputs with a thorough comparison of the Meso-NH simulations with fields measurements on three days of the IOP: 22 June, 23 June and 25 June. We also investigate the structure of the boundary layer on IOP2a when the Mistral is superimposed on a sea breeze. Then, we describe the spatial and diurnal variability of the ABL depths over the ESCOMPTE domain during the whole IOP. This step is essential if one wants to know the depth of the layer where the pollutants can be diluted or accumulated. Eventually, this study intends to describe the ABL variability in relation to local or mesoscale dynamics and/or induced topographic effects, in order to explain pollution transport processes in the low troposphere.

Investigation of the atmospheric boundary layer dynamics during the ESCOMPTE campaign

Energy Technology Data Exchange (ETDEWEB)

Said, F.; Campistron, B. [Centre de Recherches Atmospheriques, UMR CNRS 5560, Campistrous (France); Brut, A. [Centre d' Etudes Spatiales de la BIOsphere UMR 5126, Toulouse (France); Cousin, F. [Lab. d' Aerologie, UMR CNRS 5560, Toulouse (France)

2007-07-01

This paper presents some results about the behavior of the atmospheric boundary layer observed during the ESCOMPTE experiment. This campaign, which took place in south-eastern France during summer 2001, was aimed at improving our understanding of pollution episodes in relation to the dynamics of the lower troposphere. Using a large data set, as well as a simulation from the mesoscale non-hydrostatic model Meso-NH, we describe and analyze the atmosphere boundary layer (ABL) development during two specific meteorological conditions of the second Intensive Observation Period (IOP). The first situation (IOP2a, from 22 June to 23 June) corresponds to moderate, dry and cold northerly winds (end of Mistral event), coupled with a sea-breeze in the lower layer, whereas sea-breeze events with weak southerly winds occurred during the second part of the period (IOP2b, from 24 June to 26 June). In this study, we first focus on the validation of the model outputs with a thorough comparison of the Meso-NH simulations with fields measurements on three days of the IOP: 22 June, 23 June and 25 June. We also investigate the structure of the boundary layer on IOP2a when the Mistral is superimposed on a sea breeze. Then, we describe the spatial and diurnal variability of the ABL depths over the ESCOMPTE domain during the whole IOP. This step is essential if one wants to know the depth of the layer where the pollutants can be diluted or accumulated. Eventually, this study intends to describe the ABL variability in relation to local or mesoscale dynamics and/or induced topographic effects, in order to explain pollution transport processes in the low troposphere. (orig.)

Investigation of the atmospheric boundary layer dynamics during the ESCOMPTE campaign

Directory of Open Access Journals (Sweden)

F. Saïd

2007-03-01

Full Text Available This paper presents some results about the behavior of the atmospheric boundary layer observed during the ESCOMPTE experiment. This campaign, which took place in south-eastern France during summer 2001, was aimed at improving our understanding of pollution episodes in relation to the dynamics of the lower troposphere. Using a large data set, as well as a simulation from the mesoscale non-hydrostatic model Meso-NH, we describe and analyze the atmospheric boundary layer (ABL development during two specific meteorological conditions of the second Intensive Observation Period (IOP. The first situation (IOP2a, from 22 June to 23 June corresponds to moderate, dry and cold northerly winds (end of Mistral event, coupled with a sea-breeze in the lower layer, whereas sea-breeze events with weak southerly winds occurred during the second part of the period (IOP2b, from 24 June to 26 June. In this study, we first focus on the validation of the model outputs with a thorough comparison of the Meso-NH simulations with fields measurements on three days of the IOP: 22 June, 23 June and 25 June. We also investigate the structure of the boundary layer on IOP2a when the Mistral is superimposed on a sea breeze. Then, we describe the spatial and diurnal variability of the ABL depths over the ESCOMPTE domain during the whole IOP. This step is essential if one wants to know the depth of the layer where the pollutants can be diluted or accumulated. Eventually, this study intends to describe the ABL variability in relation to local or mesoscale dynamics and/or induced topographic effects, in order to explain pollution transport processes in the low troposphere.

Inflammatory bowel disease in children of middle eastern descent.

Science.gov (United States)

Naidoo, Christina Mai Ying; Leach, Steven T; Day, Andrew S; Lemberg, Daniel A

2014-01-01

Increasing rates of inflammatory bowel disease (IBD) are now seen in populations where it was once uncommon. The pattern of IBD in children of Middle Eastern descent in Australia has never been reported. This study aimed to investigate the burden of IBD in children of Middle Eastern descent at the Sydney Children's Hospital, Randwick (SCHR). The SCHR IBD database was used to identify patients of self-reported Middle Eastern ethnicity diagnosed between 1987 and 2011. Demographic, diagnosis, and management data was collected for all Middle Eastern children and an age and gender matched non-Middle Eastern IBD control group. Twenty-four patients of Middle Eastern descent were identified. Middle Eastern Crohn's disease patients had higher disease activity at diagnosis, higher use of thiopurines, and less restricted colonic disease than controls. Although there were limitations with this dataset, we estimated a higher prevalence of IBD in Middle Eastern children and they had a different disease phenotype and behavior compared to the control group, with less disease restricted to the colon and likely a more active disease course.

The eastern Asian and eastern and western North American floristic disjunction: congruent phylogenetic patterns in seven diverse genera.

Science.gov (United States)

Xiang, Q Y; Soltis, D E; Soltis, P S

1998-10-01

One of the most remarkable examples of intercontinental disjunction of the North Temperate Flora involves eastern Asia and eastern and western North America. Although there has been considerable interest in this phytogeographic pattern for over 150 years (e.g., Gray, 1859; Li, 1952; Graham, 1972; Boufford and Spongberg, 1983; Wu, 1983; Tiffney, 1985a, 1985b), relationships among taxa displaying the disjunction remain obscure. Understanding phylogenetic relationships is, however, a prerequisite for historical biogeographic analyses of this distributional pattern. To understand better the relationships of taxa displaying this intercontinental disjunction, phylogenetic analyses were conducted using a variety of DNA data sets for species of four genera (Cornus, Boykinia, Tiarella, and Trautvetteria) that occur in eastern Asia, eastern North America, and western North America. An area cladogram was constructed for each of the four genera, all of which show a similar pattern of relationship: the eastern Asian species are sister to all North American species. An identical phylogenetic pattern is also found in three other taxa exhibiting this disjunction (Aralia sect. Aralia, Calycanthus, and Adiantum pedatum). The congruent phylogenetic pattern found in these seven diverse genera raises the possibility of a common origin of the eastern Asia, eastern and western North America disjunction. The data are in agreement with the long-standing hypothesis that this well-known floristic disjunction represents the fragmentation of a once continuous Mixed Mesophytic forest community and suggest that the disjunction may have involved only two major vicariance events: an initial split between Eurasia and North America, followed by the isolation of floras between eastern and western North America. However, congruence between phylogenies and geographic distributions does not necessarily indicate an identical phytogeographic history. Taxa exhibiting the same phylogenetic pattern may have

Calcareous nannoplankton dating of the Late Quaternary deposits in Greece and the eastern Mediterranean: Case studies from terrestrial and marine sites

Directory of Open Access Journals (Sweden)

Maria V. Triantaphyllou

2015-10-01

Full Text Available The distribution and abundance of Emiliania huxleyi (E. huxleyi assemblages in the marine sediments of the Aravonitsa Plateau, Greece, and from the eastern Mediterranean are used (1 to evaluate the calcareous nannoplankton NN21a and NN21b biozones and the NN21a/NN21b boundary, and (2 to analyze the palaeoenvironmental and palaeoclimatic conditions prevailing in this interval. The sediment succession displays varied E. huxleyi assemblages and these are interpreted as reflecting climatic variability during marine isotope stages MIS 1–8.

Origin of red pelagic carbonates as an interplay of global climate and local basin factors: Insight from the Lower Devonian of the Prague Basin, Czech Republic

Czech Academy of Sciences Publication Activity Database

Bábek, O.; Faměra, Martin; Hladil, Jindřich; Kapusta, J.; Weinerová, Hedvika; Šimíček, D.; Slavík, Ladislav; Ďurišová, Jana

2018-01-01

Roč. 364, FEB (2018), s. 71-88 ISSN 0037-0738 R&D Projects: GA ČR(CZ) GA14-18183S Institutional support: RVO:61388980 ; RVO:67985831 Keywords : Bottom redox conditions * Geochemistry * Palaeoceanography * Spectral reflectance * Pragian stage * Red pelagic carbonates * Trophic levels Subject RIV: DD - Geochemistry; DB - Geology ; Mineralogy (GLU-S) OBOR OECD: Geology; Mineralogy (GLU-S) Impact factor: 2.373, year: 2016

Subgroup report on grain boundary and interphase boundary structure and properties

International Nuclear Information System (INIS)

Balluffi, R.W.; Cannon, R.M.; Clarke, D.R.; Heuer, A.H.; Ho, P.S.; Kear, B.H.; Vitek, V.; Weertman, J.R.; White, C.L.

1979-01-01

In many high temperature structural applications, the performance characteristics of a materials system are largely controlled by the properties of its grain and interphase boundaries. Failure in creep and fatigue frequently occurs by cavitation, or cracking along grain boundaries. In a few special cases, this failure problem has been overcome by directional alignment of grain and interphase boundaries by various types of metallurgical processing such as directional solidification and directional recrystallization. A good example is to be found in the application of directionally aligned structures in high performance gas-turbine airfoils. However, where fine, equiaxed grain structures are desirable, other methods of controlling grain boundary properties have been developed. Important among these has been the introduction of improvements in primary melting practices, designed to control important impurities. This is of decisive importance because even traces of certain impurity elements present in grain boundaries in high temperature materials can seriously affect properties. Impurities are deleterious and need to be removed. However, in certain cases, (e.g., creep fracture) controlled impurity additions can be beneficial and result in improved properties

Anomalous top layer in the inner core beneath the eastern hemisphere

Science.gov (United States)

Yu, W.; Wen, L.; Niu, F.

2003-12-01

Recent studies reported hemispheric variations in seismic velocity and attenuation in the top of the inner core. It, however, remains unclear how the inner core hemisphericity extends deep in the inner core. Here, we analyze PKPbc-PKIKP and PKiKP-PKIKP waveforms collected from the Global Seismographic Network (GSN), regional recordings from the German Regional Seismic Network (GRSN) and Graefenberg (GRF) sampling along the equatorial path (the ray path whose ray angle is larger than 35o from the Earth's rotation axis). The observed global and regional PKPbc-PKIKP differential traveltimes and PKIKP/PKPbc amplitude ratios suggest a simple W2 model (Wen/Niu:2002) in the western hemisphere with a constant velocity gradient of 0.049(km/sec)/100km and a Q value of 600 in the top 400 km of the inner core. In the eastern hemisphere, the data require a change of velocity gradient and Q value at about 235 km below the inner core boundary (ICB). Based on forward modeling, we construct radial velocity and attenuation models in the eastern hemisphere which can explain both the PKiKP-PKIKP and PKPbc-PKIKP observations. The inner core in the eastern hemisphere has a flat velocity gradient extending to about 235 km below the ICB. We test two solutions for the velocity models in the deeper portion of the inner core, with one having a first-order discontinuity at 235 km below the ICB with a velocity jump of 0.07(km/sec) followed by the PREM gradient, and the other having a gradual velocity transition with 0.1(km/sec)/100km gradient extended from 235 km to 375 km below the ICB followed by the PREM gradient. The observed traveltimes exclude the sharp discontinuity velocity model, as it predicts a kink in differential traveltimes at distance of 151o-152o which is not observed in the global and regional datasets. The observed PKIKP/PKPbc amplitude ratios can be best explained by a step function of attenuation with a Q value of 250 at the top 300 km and a Q value of 600 at 300-400 km

SEBARAN UNIT STOK IKAN LAYANG (Decapterus spp. DAN RISIKO PENGELOLAAN IKAN PELAGIS KECIL DI LAUT JAWA

Directory of Open Access Journals (Sweden)

Suwarso Suwarso

2013-05-01

dalam di sekitar Sulawesi (malalugis, D. macarellus. Pola migrasi ikan layang/pelagis dalam arah Laut Jawa – Selat Makasar dan sebaliknya dimungkinkan juga terkait dengan penstrukturan populasi layang tersebut. Layang scad (Decapterus russelli and round scad (D. macrosoma was a main component of small pelagic fishes around Java Sea-Makasar Strait. Increasing of uncontrolled effort of purse seine had caused a biomass decrease and clearly impact to the lower catch, so that a goal of sustainable fishery was difficult to reach; in addition, knowledge on biological characteristics and inter-relationship within the stock unit in the main zone was not understood yet. Study on stock distribution and its management impacts was conducted based on the population structuring of the two scads species exist (D. russelli and D. macrosoma which was observed fromthe genetic analyses of the mitochondria DNA marker (RFLP method, and the capture fishery data (species composition, distribution of fishing ground from some main landing sites such as Pekalongan, Samarinda, Mamuju, and Bone. Results showed the two species of scads had two sub population (stock unit respectively. D. russelli distribute in the eastern part of Java Sea, southern Flores Sea, and western Banda Sea exist as a sub population or stock unit 1, while a stock unit 2 was distributed around the coastal waters of Makasar Strait in eastern Kalimantan. However, stock unit 1 of D. macrosoma that distribute in Banda Sea was separated (clearly different from the stock unit 2 that was distributed in the coastal habitat of Flores Sea, eastern Java Sea, and the coastal area of Makasar Strait (east Kalimantan. Thus, a sustainable management of small pelagic fish in the areas of Java Sea (FMA 712 and Makasar Strait (FMA 713 have to be managed as a one stock unit (sub population and one management unit. On the other hand, we would like to propose that for a small pelagic fish that was distributed in the oceanic habitat of

Remote monitoring of the environment on boundary of the Azerbaijan Republic

International Nuclear Information System (INIS)

Pashayev, A.M.; Bayramov, A.A.; Mehdiev, A.Sh.

2002-01-01

The project of the automated remote monitoring for a level of an environment background radiation in settlements along boundary of the Azerbaijan Republic, and also along eastern suburbs occupied Azerbaijan Republic regions by Armenia's army is developed. The main purpose of the project is: Increase of a level of a radiation safety on territory of the Azerbaijan Republic; Controlling of a level of an environment background radiation on boundary of the Azerbaijan Republic with the purpose of well-timed warning and acceptance of indispensable measures at probable emergencies on Atomic Power Stations in a number adjacent from Azerbaijan countries, or other ecological catastrophes; Controlling of a level of an environment background radiation along eastern suburbs of Azerbaijan regions occupied of Armenia's army and detection of the facts of wrongful disposals of atomic engineering of Armenia on territory of Azerbaijan. As is known, in a number adjacent from Azerbaijan countries the nuclear industry is advanced or develops. It has resulted in origin of threat of a radiation hazard in case of ecological catastrophes: widely scale leakage of radioactive wastes, explosions, or fires on nuclear generating sets, acts of sabotage, directional against Azerbaijan. In this case, at unfavorable meteorological conditions a radioactive waste may be brought by a wind or a rain on territory of Azerbaijan. For example, the atomic power station constructs intensively in Islamic Republic Iran (IRI). It is necessary to estimate an initial background radiation along southern boundaries of Azerbaijan, that to determine probable changes in an ecology of southern boundaries during regular maintenance of atomic power station. Other example. In the Armenian Republic the atomic power station acts, which one is the padding center of a heightened radiation hazard in the Caucasian region. It is stipulated by several reasons: territory of Armenian Republic is heightened seismic activity, therefore

Incorporation of inorganic mercury (Hg{sup 2+}) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: The role of different plankton size fractions and species assemblages

Energy Technology Data Exchange (ETDEWEB)

Soto Cárdenas, Carolina, E-mail: sotocardenascaro@gmail.com [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina); Diéguez, Maria C. [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina); Ribeiro Guevara, Sergio [Laboratorio de Análisis por Activación Neutrónica, CAB, CNEA, Av. Bustillo Km 9.5, 8400, San Carlos de Bariloche, Río Negro (Argentina); Marvin-DiPasquale, Mark [United States Geological Survey, 345 Middlefield Rd./MS 480, Menlo Park, CA 94025 (United States); Queimaliños, Claudia P. [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina)

2014-10-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg{sup 2+}) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg{sup 2+} by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope {sup 197}Hg{sup 2+}. Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg{sup 2+} in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg{sup 2+} in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg{sup 2+} by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg{sup 2+} observed in all the plankton fractions. - Highlights: • Hg{sup 2+} incorporation in lake plankton fractions was studied using the isotope {sup 197}Hg{sup 2+}. • Hg{sup 2

Tracking atmospheric boundary layer dynamics with water vapor D-excess observations

KAUST Repository

Parkes, Stephen

2015-04-01

Stable isotope water vapor observations present a history of hydrological processes that have impacted on an air mass. Consequently, there is scope to improve our knowledge of how different processes impact on humidity budgets by determining the isotopic end members of these processes and combining them with in-situ water vapor measurements. These in-situ datasets are still rare and cover a limited geographical expanse, so expanding the available data can improve our ability to define isotopic end members and knowledge about atmospheric humidity dynamics. Using data collected from an intensive field campaign across a semi-arid grassland site in eastern Australia, we combine multiple methods including in-situ stable isotope observations to study humidity dynamics associated with the growth and decay of the atmospheric boundary layer and the stable nocturnal boundary layer. The deuterium-excess (D-excess) in water vapor is traditionally thought to reflect the sea surface temperature and relative humidity at the point of evaporation over the oceans. However, a number of recent studies suggest that land-atmosphere interactions are also important in setting the D-excess of water vapor. These studies have shown a highly robust diurnal cycle for the D-excess over a range of sites that could be exploited to better understand variations in atmospheric humidity associated with boundary layer dynamics. In this study we use surface radon concentrations as a tracer of surface layer dynamics and combine these with the D-excess observations. The radon concentrations showed an overall trend that was inversely proportional to the D-excess, with early morning entrainment of air from the residual layer of the previous day both diluting the radon concentration and increasing the D-excess, followed by accumulation of radon at the surface and a decrease in the D-excess as the stable nocturnal layer developed in the late afternoon and early evening. The stable nocturnal boundary layer

Influence of sea squirt (Halocynthia roretzi) aquaculture on benthic-pelagic coupling in coastal waters: A study of the South Sea in Korea

Science.gov (United States)

Lee, Jae Seong; Kim, Sung-Han; Kim, Yong-Tae; Hong, Sok Jin; Han, Jeong Hee; Hyun, Jung-Ho; Shin, Kyung-Hoon

2012-03-01

The influence of sea squirt aquaculture on benthic-pelagic coupling was evaluated in semi-enclosed Korean coastal waters with an in situ benthic chamber and results show for the first time that suspended sea squirt cultures play an important role in benthic-pelagic coupling in the coastal zone. Measurements of primary production, vertical particulate fluxes, and benthic fluxes were made at two stations, a sea squirt (Halocynthia roretzi) farm (SSF) and an area of organic-matter-enriched sediment in Jinhae Bay. The vertical material fluxes of organic carbon, nitrogen, and biogenic silicate (BSi) were significantly higher at SSF than in Jinhae Bay, indicating massive biodeposits in the surface sediments at SSF. The organic carbon oxidation rates (Cox) were estimated after correction for CaCO3 dissolution. The average Cox at SSF (204 mmol C m-2 d-1) was significantly higher than that in the organic-enriched Jinhae Bay sediment (77 mmol C m-2 d-1). The organic carbon burial fluxes were determined using vertical profiles of organic carbon of up to 30 cm and the sedimentation rate calculated from the excess 210Pb distribution. At both stations, ˜95% of the settled organic carbon was oxidized and only ˜5% was buried in the deep sediment layer. The benthic fluxes of dissolved inorganic nitrogen and phosphate at SSF were 2-12 times higher than in Jinhae Bay, corresponding to 85%, and 270%, respectively, of the requirements for primary production.

Rhinoplasty in Middle Eastern Patients.

Science.gov (United States)

Sajjadian, Ali

2016-01-01

Rhinoplasty in patients of Middle Eastern origin requires complete understanding of nasal morphology and an individualized approach to create a racially congruent and aesthetically pleasing outcome. In this article, common anatomic features and characteristics and detailed steps, surgical techniques, and operative maneuvers that can lead to predictable outcome in rhinoplasty of Middle Eastern patients are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Middle Eastern Christians in Europe

DEFF Research Database (Denmark)

Sparre, Sara Cathrine Lei; Hunter, Alistair; Jørgensen, Anne Rosenlund

This booklet, published in English, Danish, Swedish and Arabic, has the aim to present overall findings of the research project Defining and Identifying Middle Eastern Christians in Europe (DIMECCE) to a broader audience.......This booklet, published in English, Danish, Swedish and Arabic, has the aim to present overall findings of the research project Defining and Identifying Middle Eastern Christians in Europe (DIMECCE) to a broader audience....

Development of boundary layers

International Nuclear Information System (INIS)

Herbst, R.

1980-01-01

Boundary layers develop along the blade surfaces on both the pressure and the suction side in a non-stationary flow field. This is due to the fact that there is a strongly fluctuating flow on the downstream blade row, especially as a result of the wakes of the upstream blade row. The author investigates the formation of boundary layers under non-stationary flow conditions and tries to establish a model describing the non-stationary boundary layer. For this purpose, plate boundary layers are measured, at constant flow rates but different interferent frequency and variable pressure gradients. By introducing the sample technique, measurements of the non-stationary boundary layer become possible, and the flow rate fluctuation can be divided in its components, i.e. stochastic turbulence and periodical fluctuation. (GL) [de

The response of surface ozone to climate change over the Eastern United States

Directory of Open Access Journals (Sweden)

P. N. Racherla

2008-02-01

Full Text Available We investigate the response of surface ozone (O₃ to future climate change in the eastern United States by performing simulations corresponding to present (1990s and future (2050s climates using an integrated model of global climate, tropospheric gas-phase chemistry, and aerosols. A future climate has been imposed using ocean boundary conditions corresponding to the IPCC SRES A2 scenario for the 2050s decade. Present-day anthropogenic emissions and CO₂/CH₄ mixing ratios have been used in both simulations while climate-sensitive emissions were allowed to vary with the simulated climate. The severity and frequency of O₃ episodes in the eastern U.S. increased due to future climate change, primarily as a result of increased O₃ chemical production. The 95th percentile O₃ mixing ratio increased by 5 ppbv and the largest frequency increase occured in the 80–90 ppbv range; the US EPA's current 8-h ozone primary standard is 80 ppbv. The increased O₃ chemical production is due to increases in: 1 natural isoprene emissions; 2 hydroperoxy radical concentrations resulting from increased water vapor concentrations; and, 3 NO_x concentrations resulting from reduced PAN. The most substantial and statistically significant (p<0.05 increases in episode frequency occurred over the southeast and midatlantic U.S., largely as a result of 20% higher annual-average natural isoprene emissions. These results suggest a lengthening of the O₃ season over the eastern U.S. in a future climate to include late spring and early fall months. Increased chemical production and shorter average lifetime are two consistent features of the seasonal response of surface O₃, with increased dry deposition loss rates contributing most to the reduced lifetime in all seasons except summer. Significant interannual variability is observed in the frequency of O₃

Trophic interactions of the pelagic ecosystem over the Reykjanes Ridge as evaluated by fatty acid and stable isotope analyses

Science.gov (United States)

Petursdottir, H.; Gislason, A.; Falk-Petersen, S.; Hop, H.; Svavarsson, J.

2008-01-01

Trophic relationships of the important oceanic crustacean species Calanus finmarchicus, Meganyctiphanes norvegica and Sergestes arcticus, as well as the mesopelagic fishes Maurolicus muelleri, Benthosema glaciale and Sebastes mentella, were investigated over the Reykjanes Ridge in June 2003 and in June 2004. Measurements were performed of length, wet weight, dry weight, total lipid, lipid class, fatty acid and fatty alcohol profiles and stable isotopes (δ 13C and δ 15N). High amounts of the Calanus lipid markers, 20:1(n-9) and 22:1(n-11) in these species confirm the importance of Calanus spp. in this ecosystem. Comparisons of fatty acid/alcohol profiles by multivariate analysis revealed two main trophic pathways over the Reykjanes Ridge. In one pathway, Calanus spp. was an important part of the diet for the small mesopelagic fish species M. muelleri and B. glaciale and the shrimp S. arcticus, whereas in the other pathway, the euphausiid M. norvegica was the dominant food for the redfish S. mentella, and Calanus spp. were of less importance. M. muelleri and the smaller B. glaciale feed on C. finmarchicus, whereas the larger B. glaciale and S. arcticus select the larger, deeper-living C. hyperboreus. All investigated species are true pelagic species except for the shrimp S. arcticus, which seems to have a benthic feeding habit as well. The δ 15N levels show that of the species investigated, C. finmarchicus occupies the lowest trophic level (2.0) and the redfish, S. mentella, the highest (4.2). All the species were lipid rich, typical for subarctic pelagic ecosystem. Calanus finmarchicus, S. arcticus and B. glaciale store wax esters as their lipid stores, while M. norvegica, M. muelleri and S. mentella store triacylglycerols.

Biomagnification of organic pollutants in benthic and pelagic marine food chains from the Baltic Sea

International Nuclear Information System (INIS)

Nfon, Erick; Cousins, Ian T.; Broman, Dag

2008-01-01

The trophic transfer of organic pollutants with varying physical chemical properties was determined in both a pelagic and benthic food chain using δ 15 N as a continuous variable for assessing trophic levels. The trophic transfer of organic pollutants through the entire food chain in terms of food chain magnification factors (FCMFs) was quantified from the slope of the regression between ln [concentration] and δ 15 N. Organic pollutants with statistically significant FCMFs > 1 were considered to biomagnify within the food chain, whereas those with FCMFs 1 were found for PCB congeners and organochlorine pesticides in the Baltic food chains whereas statistically significant FCMFs 15 N method suggested a food chain structure which was not consistent with the known dietary patterns of the species. Biomagnification factors (BMFs) were additionally calculated as the ratio of the lipid normalized concentrations in the predator and prey species with adjustment for trophic level and were generally consistent with the FCMFs with BMF > 1 for PCBs and organochlorines

Eastern Africa Social Science Research Review: Contact

African Journals Online (AJOL)

Eastern Africa Social Science Research Review: Contact. Journal Home > About the Journal > Eastern Africa Social Science Research Review: Contact. Log in or Register to get access to full text downloads.

The Implications of Strike-Slip Earthquake Source Properties on the Transform Boundary Development Process

Science.gov (United States)

Neely, J. S.; Huang, Y.; Furlong, K.

2017-12-01

Subduction-Transform Edge Propagator (STEP) faults, produced by the tearing of a subducting plate, allow us to study the development of a transform plate boundary and improve our understanding of both long-term geologic processes and short-term seismic hazards. The 280 km long San Cristobal Trough (SCT), formed by the tearing of the Australia plate as it subducts under the Pacific plate near the Solomon and Vanuatu subduction zones, shows along-strike variations in earthquake behaviors. The segment of the SCT closest to the tear rarely hosts earthquakes > Mw 6, whereas the SCT sections more than 80 - 100 km from the tear experience Mw7 earthquakes with repeated rupture along the same segments. To understand the effect of cumulative displacement on SCT seismicity, we analyze b-values, centroid-time delays and corner frequencies of the SCT earthquakes. We use the spectral ratio method based on Empirical Green's Functions (eGfs) to isolate source effects from propagation and site effects. We find high b-values along the SCT closest to the tear with values decreasing with distance before finally increasing again towards the far end of the SCT. Centroid time-delays for the Mw 7 strike-slip earthquakes increase with distance from the tear, but corner frequency estimates for a recent sequence of Mw 7 earthquakes are approximately equal, indicating a growing complexity in earthquake behavior with distance from the tear due to a displacement-driven transform boundary development process (see figure). The increasing complexity possibly stems from the earthquakes along the eastern SCT rupturing through multiple asperities resulting in multiple moment pulses. If not for the bounding Vanuatu subduction zone at the far end of the SCT, the eastern SCT section, which has experienced the most displacement, might be capable of hosting larger earthquakes. When assessing the seismic hazard of other STEP faults, cumulative fault displacement should be considered a key input in

Population subdivision of hydrothermal vent polychaete Alvinella pompejana across equatorial and Easter Microplate boundaries.

Science.gov (United States)

Jang, Sook-Jin; Park, Eunji; Lee, Won-Kyung; Johnson, Shannon B; Vrijenhoek, Robert C; Won, Yong-Jin

2016-10-28

The Equator and Easter Microplate regions of the eastern Pacific Ocean exhibit geomorphological and hydrological features that create barriers to dispersal for a number of animals associated with deep-sea hydrothermal vent habitats. This study examined effects of these boundaries on geographical subdivision of the vent polychaete Alvinella pompejana. DNA sequences from one mitochondrial and eleven nuclear genes were examined in samples collected from ten vent localities that comprise the species' known range from 23°N latitude on the East Pacific Rise to 38°S latitude on the Pacific Antarctic Ridge. Multi-locus genotypes inferred from these sequences clustered the individual worms into three metapopulation segments - the northern East Pacific Rise (NEPR), southern East Pacific Rise (SEPR), and northeastern Pacific Antarctic Ridge (PAR) - separated by the Equator and Easter Microplate boundaries. Genetic diversity estimators were negatively correlated with tectonic spreading rates. Application of the isolation-with-migration (IMa2) model provided information about divergence times and demographic parameters. The PAR and NEPR metapopulation segments were estimated to have split roughly 4.20 million years ago (Mya) (2.42-33.42 Mya, 95 % highest posterior density, (HPD)), followed by splitting of the SEPR and NEPR segments about 0.79 Mya (0.07-6.67 Mya, 95 % HPD). Estimates of gene flow between the neighboring regions were mostly low (2 Nm  SEPR > PAR. Highly effective dispersal capabilities allow A. pompejana to overcome the temporal instability and intermittent distribution of active hydrothermal vents in the eastern Pacific Ocean. Consequently, the species exhibits very high levels of genetic diversity compared with many co-distributed vent annelids and mollusks. Nonetheless, its levels of genetic diversity in partially isolated populations are inversely correlated with tectonic spreading rates. As for many other vent taxa, this pioneering colonizer is

Millimeter-Sized Marine Plastics: A New Pelagic Habitat for Microorganisms and Invertebrates

Science.gov (United States)

Reisser, Julia; Shaw, Jeremy; Hallegraeff, Gustaaf; Proietti, Maira; Barnes, David K. A.; Thums, Michele; Wilcox, Chris; Hardesty, Britta Denise; Pattiaratchi, Charitha

2014-01-01

Millimeter-sized plastics are abundant in most marine surface waters, and known to carry fouling organisms that potentially play key roles in the fate and ecological impacts of plastic pollution. In this study we used scanning electron microscopy to characterize biodiversity of organisms on the surface of 68 small floating plastics (length range = 1.7–24.3 mm, median = 3.2 mm) from Australia-wide coastal and oceanic, tropical to temperate sample collections. Diatoms were the most diverse group of plastic colonizers, represented by 14 genera. We also recorded ‘epiplastic’ coccolithophores (7 genera), bryozoans, barnacles (Lepas spp.), a dinoflagellate (Ceratium), an isopod (Asellota), a marine worm, marine insect eggs (Halobates sp.), as well as rounded, elongated, and spiral cells putatively identified as bacteria, cyanobacteria, and fungi. Furthermore, we observed a variety of plastic surface microtextures, including pits and grooves conforming to the shape of microorganisms, suggesting that biota may play an important role in plastic degradation. This study highlights how anthropogenic millimeter-sized polymers have created a new pelagic habitat for microorganisms and invertebrates. The ecological ramifications of this phenomenon for marine organism dispersal, ocean productivity, and biotransfer of plastic-associated pollutants, remains to be elucidated. PMID:24941218

The Electrical Resistivity Structure of the Eastern Anatolian Collision Zone, Northeastern Anatolia

Science.gov (United States)

Cengiz, Özlem; Tuǧrul Başokur, Ahmet; Tolak Çiftçi, Elif

2016-04-01

The Northeastern Anatolia is located at the intensely deformed Eastern Anatolian Collision Zone (EACZ), and its tectonic framework is characterized by the collision of the Arabian plate with Eurasian. Although extensive attention is given to understand the crustal and upper mantle processes at this convergent boundary, there is still an ongoing debate over the geodynamic processes of the region. In this study, we were specifically interested in the geoelectric properties and thus geodynamics of the crust beneath the EACZ. Magnetotelluric (MT) measurements were made on two profiles across the north of the EACZ in 1998 as part of a national project undertaken by the Turkish Petroleum Corporation (TPAO). MT data in the frequency range of 300-0.001 Hz were collected from 168 stations located along 78 km north to south and 47 km west to east profiles where direct convergence occurs between Arabian and Eurasian plates. Two and three-dimensional inversion algorithms were used to obtain resistivity models of the study area. According to these models, the upper crust consists of low resistivity sedimentary rocks (basement rocks of the Eastern Anatolian Accretionary Complex and Pontides. While the upper and lower crustal resistivity at the northern part of the study area shows a layered structure, significant horizontal and vertical variations for the rest of the EACZ exists on resistivity models. The broad low resistivity zones (structure supports the southward subduction model with the resistive continental block and the deep conductive zones presumably corresponding to the oceanic crust.

Eastern Africa Social Science Research Review

African Journals Online (AJOL)

The Eastern Africa Social Science Research Review (EASSRR) is a bi-annual journal published by the Organization for Social Science Research in Eastern Africa (OSSREA). Since the publication of its maiden ... Emerging regions in Ethiopia: are they catching up with the rest of Ethiopia? EMAIL FULL TEXT EMAIL FULL ...

Babesia microti infection, eastern Pennsylvania, USA.

Science.gov (United States)

Acosta, Marcela E Perez; Ender, Peter T; Smith, Erin M; Jahre, Jeffrey A

2013-07-01

Infection with Babesia microti has not been well-described in eastern Pennsylvania, USA, despite the vector of this organism being prevalent. We report 3 cases of babesiosis in eastern Pennsylvania in persons without recent travel outside the region or history of blood transfusions, suggesting emergence of this infection.

76 FR 7833 - Texas Eastern Transmission, LP; Notice of Application

Science.gov (United States)

2011-02-11

...] Texas Eastern Transmission, LP; Notice of Application Take notice that on January 25, 2011, Texas Eastern Transmission, LP (Texas Eastern), 5400 Westheimer Court, Houston, Texas 77056, filed in the above... TEAM 2012 Project. Specifically, Texas Eastern requests: (i) Authorization under NGA sections 7(b) and...

The Canary Basin contribution to the seasonal cycle of the Atlantic Meridional Overturning Circulation at 26°N

Science.gov (United States)

Pérez-Hernández, M. D.; McCarthy, G. D.; Vélez-Belchí, P.; Smeed, D. A.; Fraile-Nuez, E.; Hernández-Guerra, A.

2015-11-01

This study examines the seasonal cycle of the Atlantic Meridional Overturning Circulation (AMOC) and its eastern boundary contributions. The cycle has a magnitude of 6 Sv, as measured by the RAPID/MOCHA/WBTS project array at 26°N, which is driven largely by the eastern boundary. The eastern boundary variations are explored in the context of the regional circulation around the Canary Islands. There is a 3 month lag between maximum wind forcing and the largest eastern boundary transports, which is explained in terms of a model for Rossby wave generated at the eastern boundary. Two dynamic processes take place through the Lanzarote Passage (LP) in fall: the recirculation of the Canary Current and the northward flow of the Intermediate Poleward Undercurrent. In contrast, during the remaining seasons the transport through the LP is southward due to the Canary Upwelling Current. These processes are linked to the seasonal cycle of the AMOC.

Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays

Directory of Open Access Journals (Sweden)

Maria P. Charry

2018-05-01

Full Text Available Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid Quinquelaophonte sp., and in the planktonic calanoid Gladioferens pectinatus, two New Zealand copepod species. The sediment samples from the estuary tributary sites significantly impacted reproduction in Quinquelaophonte sp. However, results from one of the estuary sites were not significantly different to those from the tributaries sites, suggesting that chemicals other than trace metals, polycyclic aromatic hydrocarbons and ammonia may be the causative stressors. Sediment elutriate samples had significant effects on reproductive endpoints in G. pectinatus, and on the induction of DNA damage in cells, as shown by the comet assay. The results indicate that sediment contamination at the Ahuriri Estuary has the potential to impact biological processes of benthic and pelagic organisms. The approach used provides a standardized methodology to assess the toxicity of estuarine sediments.

Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays.

Science.gov (United States)

Charry, Maria P; Keesing, Vaughan; Costello, Mark; Tremblay, Louis A

2018-01-01

Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid Quinquelaophonte sp., and in the planktonic calanoid Gladioferens pectinatus , two New Zealand copepod species. The sediment samples from the estuary tributary sites significantly impacted reproduction in Quinquelaophonte sp. However, results from one of the estuary sites were not significantly different to those from the tributaries sites, suggesting that chemicals other than trace metals, polycyclic aromatic hydrocarbons and ammonia may be the causative stressors. Sediment elutriate samples had significant effects on reproductive endpoints in G. pectinatus , and on the induction of DNA damage in cells, as shown by the comet assay. The results indicate that sediment contamination at the Ahuriri Estuary has the potential to impact biological processes of benthic and pelagic organisms. The approach used provides a standardized methodology to assess the toxicity of estuarine sediments.

78 FR 43874 - Texas Eastern Transmission, LP; Notice of Application

Science.gov (United States)

2013-07-22

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. CP13-514-000] Texas Eastern Transmission, LP; Notice of Application On July 2, 2013, Texas Eastern Transmission, LP (Texas Eastern) filed... natural gas facilities no longer in service. As described more fully in the Application, Texas Eastern...

76 FR 41755 - Eastern Arizona Counties Resource Advisory; Meeting

Science.gov (United States)

2011-07-15

... DEPARTMENT OF AGRICULTURE Forest Service Eastern Arizona Counties Resource Advisory; Meeting AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Eastern Arizona Counties Resource... FURTHER INFORMATION CONTACT: Julia Faith Rivera, RAC Program Manager, Eastern Arizona Counties Resource...