Geodesy: Modeling Earth's Post-Glacial Rebound

NASA Astrophysics Data System (ADS)

Spada, Giorgio; Antonioli, Andrea; Boschi, Lapo; Brandi, Valter; Cianetti, Spina; Galvani, Gabriele; Giunchi, Carlo; Perniola, Bruna; Agostinetti, Nicola Piana; Piersanti, Antonio; Stocchi, Paolo

2004-02-01

Efforts to mathematically model the Earth's post-glacial rebound, or, in general, long-term planetary-scale viscoelastic deformations, have been ongoing for several decades. Unfortunately, research in the post-glacial rebound community has not been characterized by much exchange of knowledge. Groups around the world have developed their code independently, sometimes with profoundly different approaches, occasionally leading to inconsistent results [e.g., Boschi et al., 1999]. Postglacial Rebound Calculator (TABOO) is a post-glacial rebound software that is being made freely available (through Samizdat Press at http://samizdat.mines.edu/taboo/)in the hope that it might become a common reference for all post-glacial rebound researchers. TABOO is portable and has been tested on Unix, Linux, and Windows systems; all it requires is a Fortran90 compiler supporting quadruple precision. The software is easy to use. It comes with a detailed guide that can work as a quick reference cookbook, and it is also accompanied by a textbook, The Theory Behind TABOO, collecting the most significant theoretical results from post-glacial rebound literature. TABOO is not a ``black-box,'' although it may easily be used as such. The entire source code is provided and should be easy to understand for intermediate-level Fortran programmers.

Spatial genetic structure in Beta vulgaris subsp. maritima and Beta macrocarpa reveals the effect of contrasting mating system, influence of marine currents, and footprints of postglacial recolonization routes.

PubMed

Leys, Marie; Petit, Eric J; El-Bahloul, Yasmina; Liso, Camille; Fournet, Sylvain; Arnaud, Jean-François

2014-05-01

Understanding the factors that contribute to population genetic divergence across a species' range is a long-standing goal in evolutionary biology and ecological genetics. We examined the relative importance of historical and ecological features in shaping the present-day spatial patterns of genetic structure in two related plant species, Beta vulgaris subsp. maritima and Beta macrocarpa. Using nuclear and mitochondrial markers, we surveyed 93 populations from Brittany (France) to Morocco - the southern limit of their species' range distribution. Whereas B. macrocarpa showed a genotypic structure and a high level of genetic differentiation indicative of selfing, the population genetic structure of B. vulgaris subsp. maritima was consistent with an outcrossing mating system. We further showed (1) a strong geographic clustering in coastal B. vulgaris subsp. maritima populations that highlighted the influence of marine currents in shaping different lineages and (2) a peculiar genetic structure of inland B. vulgaris subsp. maritima populations that could indicate the admixture of distinct evolutionary lineages and recent expansions associated with anthropogenic disturbances. Spatial patterns of nuclear diversity and differentiation also supported a stepwise recolonization of Europe from Atlantic-Mediterranean refugia after the last glacial period, with leading-edge expansions. However, cytoplasmic diversity was not impacted by postglacial recolonization: stochastic long-distance seed dispersal mediated by major oceanic currents may mitigate the common patterns of reduced cytoplasmic diversity observed for edge populations. Overall, the patterns we documented here challenge the general view of reduced genetic diversity at the edge of a species' range distribution and provide clues for understanding how life-history and major geographic features interact to shape the distribution of genetic diversity.

Spatial genetic structure in Beta vulgaris subsp. maritima and Beta macrocarpa reveals the effect of contrasting mating system, influence of marine currents, and footprints of postglacial recolonization routes

PubMed Central

Leys, Marie; Petit, Eric J; El-Bahloul, Yasmina; Liso, Camille; Fournet, Sylvain; Arnaud, Jean-François

2014-01-01

Understanding the factors that contribute to population genetic divergence across a species' range is a long-standing goal in evolutionary biology and ecological genetics. We examined the relative importance of historical and ecological features in shaping the present-day spatial patterns of genetic structure in two related plant species, Beta vulgaris subsp. maritima and Beta macrocarpa. Using nuclear and mitochondrial markers, we surveyed 93 populations from Brittany (France) to Morocco – the southern limit of their species' range distribution. Whereas B. macrocarpa showed a genotypic structure and a high level of genetic differentiation indicative of selfing, the population genetic structure of B. vulgaris subsp. maritima was consistent with an outcrossing mating system. We further showed (1) a strong geographic clustering in coastal B. vulgaris subsp. maritima populations that highlighted the influence of marine currents in shaping different lineages and (2) a peculiar genetic structure of inland B. vulgaris subsp. maritima populations that could indicate the admixture of distinct evolutionary lineages and recent expansions associated with anthropogenic disturbances. Spatial patterns of nuclear diversity and differentiation also supported a stepwise recolonization of Europe from Atlantic-Mediterranean refugia after the last glacial period, with leading-edge expansions. However, cytoplasmic diversity was not impacted by postglacial recolonization: stochastic long-distance seed dispersal mediated by major oceanic currents may mitigate the common patterns of reduced cytoplasmic diversity observed for edge populations. Overall, the patterns we documented here challenge the general view of reduced genetic diversity at the edge of a species' range distribution and provide clues for understanding how life-history and major geographic features interact to shape the distribution of genetic diversity. PMID:24963380

Postglacial range shift and demographic expansion of the marine intertidal snail Batillaria attramentaria

PubMed Central

Ho, Phuong-Thao; Kwan, Ye-Seul; Kim, Boa; Won, Yong-Jin

2015-01-01

To address the impacts of past climate changes, particularly since the last glacial period, on the history of the distribution and demography of marine species, we investigated the evolutionary and demographic responses of the intertidal batillariid gastropod, Batillaria attramentaria, to these changes, using the snail as a model species in the northwest Pacific. We applied phylogeographic and divergence population genetic approaches to mitochondrial COI sequences from B. attramentaria. To cover much of its distributional range, 197 individuals collected throughout Korea and 507 publically available sequences (mostly from Japan) were used. Finally, a Bayesian skyline plot (BSP) method was applied to reconstruct the demographic history of this species. We found four differentiated geographic groups around Korea, confirming the presence of two distinct, geographically subdivided haplogroups on the Japanese coastlines along the bifurcated routes of the warm Tsushima and Kuroshio Currents. These two haplogroups were estimated to have begun to split approximately 400,000 years ago. Population divergence analysis supported the hypothesis that the Yellow Sea was populated by a northward range expansion of a small fraction of founders that split from a southern ancestral population since the last glacial maximum (LGM: 26,000–19,000 years ago), when the southern area became re-submerged. BSP analyses on six geographically and genetically defined groups in Korea and Japan consistently demonstrated that each group has exponentially increased approximately since the LGM. This study resolved the phylogeography of B. attramentaria as a series of events connected over space and time; while paleoceanographic conditions determining the connectivity of neighboring seas in East Asia are responsible for the vicariance of this species, the postglacial sea-level rise and warming temperatures have played a crucial role in rapid range shifts and broad demographic expansions of its populations. PMID:25691968

Surficial geology and benthic habitat of the German Bank seabed, Scotian Shelf, Canada

USGS Publications Warehouse

Todd, Brian J.; Kostylev, Vladimir E.

2011-01-01

To provide the scientific context for management of a newly opened scallop fishing ground, surficial geology and benthic habitats were mapped on German Bank on the southern Scotian Shelf off Atlantic Canada. To provide a seamless regional dataset, multibeam sonar surveys covered 5320 sqaure kilometres of the bank in water depths of 30–250 m and provided 5 m horizontal resolution bathymetry and backscatter strength. Geoscience data included high-resolution geophysical profiles (seismic reflection and sidescan sonar) and seabed sediment samples. Geological interpretation and is overlain in places by glacial and postglacial sediment. Biological data included seafloor video transects and photographs from which 127 taxa of visible megabenthos were identified. Trawl bycatch data were obtained from government annual research surveys. Statistical analysis of revealed that bedrock is exposed at the seafloor on much of German Bankthese two datasets and a suite of oceanographic environmental variables demonstrated that significantly different fauna exist on bedrock, glacial sediment and postglacial sediment.

The Mintom Formation (new): Sedimentology and geochemistry of a Neoproterozoic, Paralic succession in south-east Cameroon

NASA Astrophysics Data System (ADS)

Caron, V.; Ekomane, E.; Mahieux, G.; Moussango, P.; Ndjeng, E.

2010-06-01

This paper presents a lithologic and stratigraphic description of the Neoproterozoic (ante- or syn- Pan-African orogeny) Mintom Formation (new) of southeastern Cameroon, and provides a new facies and geochemical analysis of the sedimentary succession, formerly referred to as the upper Dja series. The Mintom Formation can be subdivided from base to top into four members that record a general increase in carbonate content. The members (all new) from lower to upper are: Kol Member (diamictite and pelite), Metou Member (dolostone), Momibolé Member (calcareous pelite), and Atog Adjap Member (limestone). Although the lithostratigraphic architecture looks very similar to that of well-documented syn- and post-glacial Neoproterozoic deposits, physical evidence of glacial influence is absent. By contrast with other Central African Neoproterozoic carbonates deposited in ramp settings, the succession does not contain open marine facies. Limestones consist of monotonous subhedral microsparitic calcite mosaics and display occasional microbial laminae. These observations force reevaluation of both previous paleoenvironmental interpretations of the deposits and their comparison with neighboring Ediacaran carbonates. We assume that the graded basal succession from diamictite to laminated pelitic facies is compatible with emplacement of mass flow deposits in toe-of-slope setting during regional uplift. Interpretation of the overlying Métou dolostone is uncertain though sedimentological and geochemical properties point to a likely quiet depositional setting. The upper part of the Formation, including the Momibolé and Atog Adjap Members, is conspicuously laminated, in places rhythmically and ripple-bedded, suggesting shallow subaqueous and calm depositional conditions only interrupted by occasional slumps indicative of a locally steepened bottom topography. Evaporitic fabrics and fenestral pores further indicate shallow water, possibly peritidal, environmental conditions. In spite of indications of shale and post-depositional contamination, rare earth elements (REE) plus yttrium (Y) patterns obtained from carbonate samples point to a non-marine origin for the Atog Adjap limestone, but instead deposition in lacustrine or lagoonal settings under freshwater influence. This interpretation suggests that the Mintom Formation formed in a small-scale palaeodepression, isolated from the open marine environment, where confined lagoonal or lacustrine sedimentation developed. The final Neoproterozoic evolution of the Mintom Formation was dominated by erosional features, including striations and stair-cased groove structures reported for the first time here, and revealing the passage of glaciers of likely Ediacaran age.

Post-glacial redistribution and shifts in productivity of giant kelp forests

PubMed Central

Graham, Michael H.; Kinlan, Brian P.; Grosberg, Richard K.

2010-01-01

Quaternary glacial–interglacial cycles create lasting biogeographic, demographic and genetic effects on ecosystems, yet the ecological effects of ice ages on benthic marine communities are unknown. We analysed long-term datasets to develop a niche-based model of southern Californian giant kelp (Macrocystis pyrifera) forest distribution as a function of oceanography and geomorphology, and synthesized palaeo-oceanographic records to show that late Quaternary climate change probably drove high millennial variability in the distribution and productivity of this foundation species. Our predictions suggest that kelp forest biomass increased up to threefold from the glacial maximum to the mid-Holocene, then rapidly declined by 40–70 per cent to present levels. The peak in kelp forest productivity would have coincided with the earliest coastal archaeological sites in the New World. Similar late Quaternary changes in kelp forest distribution and productivity probably occurred in coastal upwelling systems along active continental margins worldwide, which would have resulted in complex shifts in the relative productivity of terrestrial and marine components of coastal ecosystems. PMID:19846450

Historical contingency and ecological determinism interact to prime speciation in sticklebacks, Gasterosteus.

PubMed Central

Taylor, E B; McPhail, J D

2000-01-01

Historical contingency and determinism are often cast as opposing paradigms under which evolutionary diversification operates. It may be, however, that both factors act together to promote evolutionary divergence, although there are few examples of such interaction in nature. We tested phylogenetic predictions of an explicit historical model of divergence (double invasions of freshwater by marine ancestors) in sympatric species of three-spined sticklebacks (Gasterosteus aculeatus) where determinism has been implicated as an important factor driving evolutionary novelty. Microsatellite DNA variation at six loci revealed relatively low genetic variation in freshwater populations, supporting the hypothesis that they were derived by colonization of freshwater by more diverse marine ancestors. Phylogenetic and genetic distance analyses suggested that pairs of sympatric species have evolved multiple times, further implicating determinism as a factor in speciation. Our data also supported predictions based on the hypothesis that the evolution of sympatric species was contingent upon 'double invasions' of postglacial lakes by ancestral marine sticklebacks. Sympatric sticklebacks, therefore, provide an example of adaptive radiation by determinism contingent upon historical conditions promoting unique ecological interactions, and illustrate how contingency and determinism may interact to generate geographical variation in species diversity PMID:11133026

Select, High-Resolution Windows Into Sub-Centennial-Scale Climate Variability in the Western Pacific Warm Pool Between 7 and 12 ka

NASA Astrophysics Data System (ADS)

Quinn, T. M.; Taylor, F. W.; Cheng, H.; Edwards, R. L.; Burr, G.; Chen, Y.

2004-12-01

Post-glacial, coral-based climate records from the Western Pacific Warm Pool (WPWP), a region that serves as a major heat and moisture source to the ocean-atmosphere system, provide sub-annually resolved windows into climate variability on interannual to multi-decadal timescales from this climatologically significant region. Paleoclimate reconstructions based on fossil corals require that the skeletal geochemistry be unaffected by diagenesis and that secular changes in seawater chemistry be known. Global seawater \\delta18O variations can be constrained using knowledge of past variations in ice volume, whereas much less is known about global seawater Sr/Ca variations, if they occur in the post-glacial interval. Our paleoclimate reconstructions are based on monthly resolved \\delta18O and Sr/Ca records in fossil Porites corals from the Western Solomon Islands ( ˜8° S, ˜157° E; Tetepare and Rendova). Post-depositional alteration of our fossil coral samples is minimal based on mineralogic (XRD), petrographic (SEM) and geochemical criteria (preservation of modern marine initial \\delta234U values). Four of these fossil coral time series are of particular interest: 99RND (age, 7,992±42; ~45 years), 01T-B (age, 7,647±73; ~65 years), 01T-AQ (age, 10,208±44; ~30 years), and 99TET-B (age, 11,987±69; ~ 30 years). We apply a model that uses simultaneous variations in coral \\delta18O and Sr/Ca in combination with estimates of post-glacial changes in seawater chemistry to reconstruct mean climate state during the early Holocene and the Younger Dryas. Model results indicate that on average SSTs in the WPWP were within 1° C of modern and that surface waters were more saline than modern during each of the four time intervals during which our fossil corals grew.

High-resolution seismic reflection imaging of growth folding and shallow faults beneath the Southern Puget Lowland, Washington State

USGS Publications Warehouse

Clement, C.R.; Pratt, T.L.; Holmes, M.L.; Sherrod, B.L.

2010-01-01

Marine seismic reflection data from southern Puget Sound, Washington, were collected to investigate the nature of shallow structures associated with the Tacoma fault zone and the Olympia structure. Growth folding and probable Holocene surface deformation were imaged within the Tacoma fault zone beneath Case and Carr Inlets. Shallow faults near potential field anomalies associated with the Olympia structure were imaged beneath Budd and Eld Inlets. Beneath Case Inlet, the Tacoma fault zone includes an ???350-m wide section of south-dipping strata forming the upper part of a fold (kink band) coincident with the southern edge of an uplifted shoreline terrace. An ???2 m change in the depth of the water bottom, onlapping postglacial sediments, and increasing stratal dips with increasing depth are consistent with late Pleistocene to Holocene postglacial growth folding above a blind fault. Geologic data across a topographic lineament on nearby land indicate recent uplift of late Holocene age. Profiles acquired in Carr Inlet 10 km to the east of Case Inlet showed late Pleistocene or Holocene faulting at one location with ???3 to 4 m of vertical displacement, south side up. North of this fault the data show several other disruptions and reflector terminations that could mark faults within the broad Tacoma fault zone. Seismic reflection profiles across part of the Olympia structure beneath southern Puget Sound show two apparent faults about 160 m apart having 1 to 2 m of displacement of subhorizontal bedding. Directly beneath one of these faults, a dipping reflector that may mark the base of a glacial channel shows the opposite sense of throw, suggesting strike-slip motion. Deeper seismic reflection profiles show disrupted strata beneath these faults but little apparent vertical offset, consistent with strike-slip faulting. These faults and folds indicate that the Tacoma fault and Olympia structure include active structures with probable postglacial motion.

High-resolution seismic reflection imaging of growth folding and shallow faults beneath the Southern Puget Lowland, Washington State

USGS Publications Warehouse

Odum, Jackson K.; Stephenson, William J.; Pratt, Thomas L.; Blakely, Richard J.

2016-01-01

Marine seismic reflection data from southern Puget Sound, Washington, were collected to investigate the nature of shallow structures associated with the Tacoma fault zone and the Olympia structure. Growth folding and probable Holocene surface deformation were imaged within the Tacoma fault zone beneath Case and Carr Inlets. Shallow faults near potential field anomalies associated with the Olympia structure were imaged beneath Budd and Eld Inlets. Beneath Case Inlet, the Tacoma fault zone includes an ∼350-m wide section of south-dipping strata forming the upper part of a fold (kink band) coincident with the southern edge of an uplifted shoreline terrace. An ∼2 m change in the depth of the water bottom, onlapping postglacial sediments, and increasing stratal dips with increasing depth are consistent with late Pleistocene to Holocene postglacial growth folding above a blind fault. Geologic data across a topographic lineament on nearby land indicate recent uplift of late Holocene age. Profiles acquired in Carr Inlet 10 km to the east of Case Inlet showed late Pleistocene or Holocene faulting at one location with ∼3 to 4 m of vertical displacement, south side up. North of this fault the data show several other disruptions and reflector terminations that could mark faults within the broad Tacoma fault zone. Seismic reflection profiles across part of the Olympia structure beneath southern Puget Sound show two apparent faults about 160 m apart having 1 to 2 m of displacement of subhorizontal bedding. Directly beneath one of these faults, a dipping reflector that may mark the base of a glacial channel shows the opposite sense of throw, suggesting strike-slip motion. Deeper seismic reflection profiles show disrupted strata beneath these faults but little apparent vertical offset, consistent with strike-slip faulting. These faults and folds indicate that the Tacoma fault and Olympia structure include active structures with probable postglacial motion.

Postglacial Terrestrial Carbon Dynamics and Atmospheric CO2

NASA Astrophysics Data System (ADS)

Prentice, C. I.; Harrison, S. P.; Kaplan, J. O.

2002-12-01

Combining PMIP climate model results from the last glacial maximum (LGM) with biome modelling indicates the involvement of both cold, dry climate and physiological effects of low atmospheric CO2 in reducing tree cover on the continents. Further results with the LPJ dynamic vegetation model agree with independent evidence for greatly reduced terrestrial carbon storage at LGM, and suggest that terrestrial carbon storage continued to increase during the Holocene. These results point to predominantly oceanic explanations for preindustrial changes in atmospheric CO2, although land changes after the LGM may have contributed indirectly by reducing the aeolian marine Fe source and (on a longer time scale) by triggering CaCO3 compensation in the ocean.

Towards a model of postglacial biogeography in shallow marine species along the Patagonian Province: lessons from the limpet Nacella magellanica (Gmelin, 1791)

PubMed Central

2012-01-01

Background Patagonia extends for more than 84,000 km of irregular coasts is an area especially apt to evaluate how historic and contemporary processes influence the distribution and connectivity of shallow marine benthic organisms. The true limpet Nacella magellanica has a wide distribution in this province and represents a suitable model to infer the Quaternary glacial legacy on marine benthic organisms. This species inhabits ice-free rocky ecosystems, has a narrow bathymetric range and consequently should have been severely affected by recurrent glacial cycles during the Quaternary. We performed phylogeographic and demographic analyses of N. magellanica from 14 localities along its distribution in Pacific Patagonia, Atlantic Patagonia, and the Falkland/Malvinas Islands. Results Mitochondrial (COI) DNA analyses of 357 individuals of N. magellanica revealed an absence of genetic differentiation in the species with a single genetic unit along Pacific Patagonia. However, we detected significant genetic differences among three main groups named Pacific Patagonia, Atlantic Patagonia and Falkland/Malvinas Islands. Migration rate estimations indicated asymmetrical gene flow, primarily from Pacific Patagonia to Atlantic Patagonia (Nem=2.21) and the Falkland/Malvinas Islands (Nem=16.6). Demographic reconstruction in Pacific Patagonia suggests a recent recolonization process (< 10 ka) supported by neutrality tests, mismatch distribution and the median-joining haplotype genealogy. Conclusions Absence of genetic structure, a single dominant haplotype, lack of correlation between geographic and genetic distance, high estimated migration rates and the signal of recent demographic growth represent a large body of evidence supporting the hypothesis of rapid postglacial expansion in this species in Pacific Patagonia. This expansion could have been sustained by larval dispersal following the main current system in this area. Lower levels of genetic diversity in inland sea areas suggest that fjords and channels represent the areas most recently colonized by the species. Hence recolonization seems to follow a west to east direction to areas that were progressively deglaciated. Significant genetic differences among Pacific, Atlantic and Falkland/Malvinas Islands populations may be also explained through disparities in their respective glaciological and geological histories. The Falkland/Malvinas Islands, more than representing a glacial refugium for the species, seems to constitute a sink area considering the strong asymmetric gene flow detected from Pacific to Atlantic sectors. These results suggest that historical and contemporary processes represent the main factors shaping the modern biogeography of most shallow marine benthic invertebrates inhabiting the Patagonian Province. PMID:22871029

Sediment property changes in response to the glacial activity on the continental slope to the eastern side of Pennell-Iselin Bank in the Ross Sea, Antarctica

NASA Astrophysics Data System (ADS)

Ha, Sangbeom; Khim, Boo-Keun; Colizza, Ester; Marci, Patrizia; Sagnotti, Leonardo; Caricchi, Chiara; Langone, Leonardo; Giglio, Federico; Kuhn, Gerhard

2017-04-01

High latitude marine environments including the Antarctic continental margin have sensitively responded to the climate change, and the Ross Sea is one of these examples. Subglacial marine sedimentary changes have been studied extensively in the continental shelf areas of the Ross Sea to understand the growth and retreat of glaciers in response to the glacial-interglacial changes. However, the continental slope areas of the Ross Sea have not been investigated comparatively less. Thus, in order to comprehend the glaciomarine sedimentation change on the continental slope of the Ross Sea, 3 gravity cores (GC1, GC2, GC3) and 3 box cores (BC1, BC2, BC3) were collected from 3 sites (RS14-C1, C2, C3 by decreasing water depth), respectively, across the continental slope to the eastern side of the Pennell-Iselin Bank during XXIX PNRA (Rosslope II) cruise in 2014. A variety of sedimentological (grain size, magnetic susceptibility, XRF) and geochemical (biogenic opal, total organic carbon, CaCO3, δ13C of organic matter) properties were analyzed along with AMS 14C dating of bulk sediments. All core sediments consist of mostly hemipelagic sandy clay or silty clay with scattered IRD (Ice-Rafted Debris). Sediment color of three cores changes consistently downward from brown to gray with some alternations in core GC1. Based on the basic sediment properties such as sediment color, grain size, and magnetic susceptibility, sediment lithology was decided to divide Unit A and Unit B, both of which were further divided into two subunits. Despite old carbon effect, AMS 14C dates confirm that Unit A belongs to the Holocene and Unit B covers the deglacial to last glacial period at the top of cores. Unit A is characterized by low TOC, low CaCO3, low biogenic opal content and low C/N ratios, whereas Unit B is characterized by high TOC, high CaCO3, moderate to high biogenic opal content and high C/N ratios. Consequently, Unit A represents the modern and interglacial sediments deposited mainly by the suspension settling of biogenic particles in the open marine condition. In contrast, because Unit B shows higher TOC, CaCO3 content and C/N ratios, these sediments might be supplied by the lateral melt-water plume or distal part of debris flow originated from the front of grounding ice in the subglacial continental shelf under the ice shelf and during the glacial or post-glacial period. Thus, Unit B contains mostly reworked and eroded continental shelf sediments and IRDs. In addition, because the peaks of biogenic opal and TOC contents at Site C1 are distinctly higher than Sites C2 and C3, surface water production occurred under seasonally open marine condition at the deeper Site C1. In conclusion, the influence of subglacial continental shelf sedimentation in terms of melt-water transport and/or distal stage of debris flow was limited as far as to Site C2 during the deglacial and glacial period. However, such depositional effect was insignificant, but the seasonal open marine condition was recognized, at the deeper Site C1 in the continental slope of the Ross Sea.

Postglacial eruptive history of the Western Volcanic Zone, Iceland

NASA Astrophysics Data System (ADS)

Sinton, John; GröNvold, Karl; SæMundsson, KristjáN.

2005-12-01

New field observations, age constraints, and extensive chemical analyses define the complete postglacial eruptive history of the 170-km-long Western Volcanic Zone (WVZ) of Iceland, the ultraslow-spreading western boundary of the south Iceland microplate. We have identified 44 separate eruptive units, 10 of which are small-volume eruptions associated with the flanking Grímsnes system. Overall chemical variations are consistent with very simplified models of melting of a source approximating primitive mantle composition. The 17 eruptions in the first 3000 years of postglacial time account for about 64% of the total postglacial production and are incompatible-element depleted compared to younger units, consistent with enhanced melting as a consequence of rebound immediately following deglaciation. Steadily declining eruption rates for the last 9000 years also correlate with changes in average incompatible element ratios that appear to reflect continued decline in melting extents to the present day. This result is not restricted to the WVZ, however, and may herald a decline in melting throughout all of western Iceland during later postglacial time. Lavas from the northern part of the WVZ are depleted in incompatible elements relative to those farther south at all times, indicating either a long-wavelength gradient in mantle source composition or variations in the melting process along axis. We find no evidence in the postglacial volcanic record for current failure of the WVZ, despite evidence for continued propagation of the eastern margin of the microplate. The dominance of lava shields in the eruptive history of the WVZ contrasts with the higher number of fissure eruptions in other Icelandic volcanic zones. WVZ shields represent long-duration, low-effusion rate eruptions fed by recharge magma arising out of the mantle. Average effusion rate is the key variable distinguishing shield and fissure eruptions, both within the WVZ and between different volcanic zones. High effusion rate, large-volume eruptions require the presence of large crustal magma reservoirs, which have been rare or absent in the WVZ throughout postglacial time.

Late Wisconsinan glaciation and postglacial relative sea-level change on western Banks Island, Canadian Arctic Archipelago

NASA Astrophysics Data System (ADS)

Lakeman, Thomas R.; England, John H.

2013-07-01

The study revises the maximum extent of the northwest Laurentide Ice Sheet (LIS) in the western Canadian Arctic Archipelago (CAA) during the last glaciation and documents subsequent ice sheet retreat and glacioisostatic adjustments across western Banks Island. New geomorphological mapping and maximum-limiting radiocarbon ages indicate that the northwest LIS inundated western Banks Island after ~ 31 14C ka BP and reached a terminal ice margin west of the present coastline. The onset of deglaciation and the age of the marine limit (22-40 m asl) are unresolved. Ice sheet retreat across western Banks Island was characterized by the withdrawal of a thin, cold-based ice margin that reached the central interior of the island by ~ 14 cal ka BP. The elevation of the marine limit is greater than previously recognized and consistent with greater glacioisostatic crustal unloading by a more expansive LIS. These results complement emerging bathymetric observations from the Arctic Ocean, which indicate glacial erosion during the Last Glacial Maximum (LGM) to depths of up to 450 m.

Phylogenetic Lineages and Postglacial Dispersal Dynamics Characterize the Genetic Structure of the Tick, Ixodes ricinus, in Northwest Europe

PubMed Central

Røed, Knut H.; Kvie, Kjersti S.; Hasle, Gunnar; Gilbert, Lucy; Leinaas, Hans Petter

2016-01-01

Dispersal and gene flow are important mechanisms affecting the dynamics of vectors and their pathogens. Here, patterns of genetic diversity were analyzed in many North European populations of the tick, Ixodes ricinus. Population sites were selected within and between areas separated by geographical barriers in order to evaluate the importance of tick transportation by birds in producing genetic connectivity across open sea and mountain ranges. The phylogenetic analyses of the mitochondrial control region and the cytochrome b gene revealed two distinct clades with supported sub-clades, with three genetic lineages: GB and WNo associated with Great Britain and western Norway respectively, and Eu with a wider distribution across continental Europe in agreement with much lower efficiency of tick dispersal by birds than by large mammals. The results suggest different ancestry of I. ricinus colonizing Britain and the rest of northern Europe, possibly from different glacial refuges, while ticks from western Norway and continental Europe share a more recent common ancestry. Demographic history modeling suggests a period of strong increase in tick abundance coincident with progression of the European Neolithic culture, long after their post-glacial colonization of NW Europe. PMID:27907193

75 FR 23587 - Annual Seattle Yacht Club's “Opening Day” Marine Parade

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-04

... Seattle Yacht Club's ``Opening Day'' Marine Parade AGENCY: Coast Guard, DHS. ACTION: Notice of enforcement..., Portage Cut (Montlake Cut), and Union Bay, WA during the Annual Seattle Yacht Club's ``Opening Day... Special Local Regulation for the annual Seattle Yacht Club's ``Opening Day'' Marine Parade in 33 CFR 100...

Post-glacial climate forcing of surface processes in the Ganges-Brahmaputra river basin and implications for carbon sequestration

NASA Astrophysics Data System (ADS)

Hein, Christopher J.; Galy, Valier; Galy, Albert; France-Lanord, Christian; Kudrass, Hermann; Schwenk, Tilmann

2017-11-01

Climate has been proposed to control both the rate of terrestrial silicate weathering and the export rate of associated sediments and terrestrial organic carbon to river-dominated margins - and thus the rate of sequestration of atmospheric CO2 in the coastal ocean - over glacial-interglacial timescales. Focused on the Ganges-Brahmaputra rivers, this study presents records of post-glacial changes in basin-scale Indian summer monsoon intensity and vegetation composition based on stable hydrogen (δD) and carbon (δ13C) isotopic compositions of terrestrial plant wax compounds preserved in the channel-levee system of the Bengal Fan. It then explores the role of these changes in controlling the provenance and degree of chemical weathering of sediments exported by these rivers, and the potential climate feedbacks through organic-carbon burial in the Bengal Fan. An observed 40‰ shift in δD and a 3-4‰ shift in both bulk organic-carbon and plant-wax δ13C values between the late glacial and mid-Holocene, followed by a return to more intermediate values during the late Holocene, correlates well with regional post-glacial paleoclimate records. Sediment provenance proxies (Sr, Nd isotopic compositions) reveal that these changes likely coincided with a subtle focusing of erosion on the southern flank of the Himalayan range during periods of greater monsoon strength and enhanced sediment discharge. However, grain-size-normalized organic-carbon concentrations in the Bengal Fan remained constant through time, despite order-of-magnitude level changes in catchment-scale monsoon precipitation and enhanced chemical weathering (recorded as a gradual increase in K/Si* and detrital carbonate content, and decrease in H2O+/Si*, proxies) throughout the study period. These findings demonstrate a partial decoupling of climate change and silicate weathering during the Holocene and that marine organic-carbon sequestration rates primary reflect rates of physical erosion and sediment export as modulated by climatic changes. Together, these results reveal the magnitude of climate changes within the Ganges-Brahmaputra basin following deglaciation and a closer coupling of monsoon strength with OC burial than with silicate weathering on millennial timescales.

Holocene evolution of Apalachicola Bay, Florida

USGS Publications Warehouse

Osterman, L.E.; Twichell, D.C.; Poore, R.Z.

2009-01-01

A program of geophysical mapping and vibracoring was conducted to better understand the geologic evolution of Apalachicola Bay. Analyses of the geophysical data and sediment cores along with age control provided by 34 AMS 14C dates on marine shells and wood reveal the following history. As sea level rose in the early Holocene, fluvial deposits filled the Apalachicola River paleochannel, which extended southward under the central part of the bay and seaward across the continental shelf. Sediments to either side of the paleochannel contain abundant wood fragments, with dates documenting that those areas were forested at 8,000 14C years b.p. As sea level continued to rise, spits formed of headland prodelta deposits. Between ???6,400 and ???2,500 14C years b.p., an Apalachicola prodelta prograded and receded several times across the inner shelf that underlies the western part of the bay. An eastern deltaic lobe was active for a shorter time, between ???5,800 and 5,100 14C years b.p. Estuarine benthic foraminiferal assemblages occurred in the western bay as early as 6,400 14C years b.p., and indicate that there was some physical barrier to open-ocean circulation and shelf species established by that time. It is considered that shoals formed in the region of the present barrier islands as the rising sea flooded an interstream divide. Estuarine conditions were established very early in the post-glacial flooding of the bay. ?? 2009 US Government.

A review of the geologic framework of the Long Island Sound Basin, with some observations relating to postglacial sedimentation

USGS Publications Warehouse

Lewis, Ralph S.; DiGiacomo-Cohen, Mary

2000-01-01

Most of the papers in this thematic section present regional perspectives that build on more than 100 years of geologic investigation in Long Island Sound. When viewed collectively, a common theme emerges in these works. The major geologic components of the Long Island Sound basin (bedrock, buried coastal-plain strata, recessional moraines, glacial-lake deposits, and the remains of a large marine delta) interact with the water body to affect the way the modern sedimentary system functions.Previous work, along with our present knowledge of the geologic framework of the Long Island Sound basin, is comprehensively reviewed with this theme in mind. Aspects of the crystalline bedrock, and the deltaic deposits associated with glacial Lake Connecticut, are examined with respect to their influence on sedimentation along the Connecticut coast and in the northern and western Sound. We also discuss the influence of the glacial drift that mantles the coastal-plain remnant along the north shore of Long Island and in the southern Sound.A total of approximately 22.7 billion m3 of marine sediment has accumulated in the Long Island Sound basin. A significant portion (44%) of the fine-grained marine section in the central and western basins was redistributed there from the eastern Sound, as tidal scour removed slightly over 5 billion m3 (5.3 X 1012 kg) of fine material from glacial lake and early-marine deposits east of the Connecticut River. The remainder of the estimated 1.2 X 1013 kg of fine-grained marine sediment that now resides in the central and western Sound can be accounted for by riverine input over the past 13.5 ka.

Sequence stratigraphy of the subaqueous Changjiang (Yangtze River) delta since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Xu, Taoyu; Wang, Guoqing; Shi, Xuefa; Wang, Xin; Yao, Zhengquan; Yang, Gang; Fang, Xisheng; Qiao, Shuqing; Liu, Shengfa; Wang, Xuchen; Zhao, Quanhong

2016-01-01

This study focuses on sedimentary research at the subaqueous Changjiang (Yangtze River) delta, based on five high-resolution seismic profiles and seven borehole cores with accurate AMS 14C datings. Three distinct seismic units were identified from the seismic profiles according to seismic reflection characteristics, and five sedimentary facies were recognized from borehole cores. These facies constituted a fining upward sedimentary sequence in relation to postglacial sea-level transgression. Three sequence surfaces (sequence boundary (SB), transgressive surface (TS), and maximum flooding surface (MFS)) demarcate the boundaries between early transgressive system tract (E-TST), late transgressive system tract (L-TST), early highstand system tract (E-HST) and late highstand system tract (L-HST), which constitute the sixth order sequence. These system tracts were developed coevally with postglacial sea-level rise. E-TST (~ 19-12 ka BP) corresponds to an incised-valley infilling in the early stages of postglacial transgression whereas L-TST (~ 12-7.5 ka BP) was formed during the last stage of postglacial transgression. The progradational structure of L-TST reflected in seismic profiles is possibly related to the intensification of the East Asian summer monsoon. E-HST (~ 7.5-2 ka BP) was deposited in response to the highstand after maximum postglacial transgression was reached, while L-HST (~ 2 ka BP-present) was initiated by accelerated progradation of the Changjiang delta.

Quaternary fluvial history of the Delaware River, New Jersey and Pennsylvania, USA: The effects of glaciation, glacioisostasy, and eustasy on a proglacial river system

NASA Astrophysics Data System (ADS)

Stanford, Scott D.; Witte, Ron W.; Braun, Duane D.; Ridge, John C.

2016-07-01

Fluvial, glacial, and estuarine deposits in the Delaware Valley record the response of the Delaware River to glaciation, sea-level change, and glacioisostasy during the Quaternary. Incision following an early Pleistocene glaciation created the present valley, which is inset into a Pliocene strath and fluvial plain. Middle and upper Pleistocene and Holocene deposits were laid down in this inset valley. Estuarine terraces in the lower valley and bayshore at + 20 m (probably Marine Isotope Stage [MIS] 11), + 8 m (MIS 5e), and + 3 m (MIS 5a or c), and a fluvial deposit that correlates to offshore MIS 3 marine deposits at - 20 m are at elevations consistent with glacioisostatic models. Successive incisions during lowstands in the middle and late Pleistocene lengthened, deepened, and narrowed the channel in the lower valley and shifted the channel westward in Delaware Bay. During MIS 2 glaciation, from 25 to 18 ka, the Delaware was diverted to the Hudson Shelf Valley by glacioisostatic tilting. Most glacial sediment was trapped in fluvial-lacustrine valley fills north of the terminal moraine. Incision of the valley fill was accomplished during the early stage of rebound, between 17 and 12 ka. Drainage to the Delaware shelf was restored between 15 and 13 ka as the forebulge collapsed. During incision, multiple postglacial terraces formed where the valley was perpendicular to rebound contours and so was steepened and elevated northward; and a single terrace formed where the valley paralleled the contours, and there was no differential elevation or steepening. About 65% of the original volume of MIS 2 glacial sediment remains in the main valley, and most of the eroded volume is in the channel in the lower valley beneath Holocene estuarine fill. Little glacial sediment reached the Delaware or Hudson shelf. Overbank deposition on the lower postglacial terrace and modern floodplain spans the Holocene. The volume of Holocene sediment in the estuary and bay yields a basinwide denudation rate of about 20 m/my.

Post-Glacial Climate Forcing of Surface Processes in the Ganges-Brahmaputra Basin and Implications for the Global Carbon Cycle

NASA Astrophysics Data System (ADS)

Hein, C. J.; Galy, V.; France-Lanord, C.; Galy, A.; Kudrass, H. R.; Peucker-Ehrenbrink, B.

2016-12-01

Silicate weathering coupled with carbonate precipitation and organic carbon (OC) burial in marine sediments are the primary mechanisms sequestering atmospheric CO2 over a range of timescales. The efficiency of both processes has long been mechanistically linked to climate: increased atmospheric CO2 sequestration under warm/wet conditions acts as a negative feedback, thereby contributing to global climate regulation. Over glacial-interglacial timescales, climate has been proposed to control the export rate of terrestrial silicate weathering products and terrestrial OC to river-dominated margins, as well as the rates of chemical weathering (i.e., the efficiency of carbon sequestration). Focused on the Ganges-Brahmaputra drainage basin, this study quantifies the relative role of climate change in the efficiency of silicate weathering and OC burial following the last glacial maximum. Stable hydrogen (δD) and carbon (δ13C) isotopic compositions of terrestrial plant wax compounds preserved in the Bengal Fan channel-levee system capture variations in the strength of the Indian summer monsoon and vegetation dynamics. Specifically, a 40‰ shift in δD and a 4‰ shift in both bulk OC and plant wax δ13C values between the late glacial and mid-Holocene, followed by a return to more intermediate values during the late Holocene, correlate well with regional post-glacial paleoclimate records. Sediment provenance proxies (Sr, Nd isotopic compositions) reveal that these changes coincided with a focusing of erosion on the southern flank of the Himalayan range during periods of greater monsoon strength and enhanced sediment discharge. However, OC loading, and thus carbon burial efficiency, in the Bengal Fan remained constant through time, demonstrating the primacy of physical erosion and climate-driven sediment export in marine OC sequestration. In contrast, a gradual increase in K/Si* and Ca/Si, and decrease in H2O+/Si*, throughout the study period may demonstrate the decoupling of climate and silicate weathering during the late Holocene, if those ratios are valid proxies for catchment-scale chemical weathering intensity. Together, these results reveal the dominant feedback between climate and sediment-export / OC-burial within the Ganges-Brahmaputra / Bengal Fan system following deglaciation.

Glacial loess or shoreface sands: a re-interpretation of the Upper Ordovician (Ashgillian) glacial Ammar Formation, Southern Jordan

NASA Astrophysics Data System (ADS)

Turner, B. R.; Makhlouf, I. M.; Armstrong, H. A.

2003-04-01

Upper Ordovician (Ashgillian) glacial deposits of the Ammar Formation, Southern Jordan, comprise locally deformed, structureless fine sandstone, incised by glacial channels filled by braided outwash plain sandstones and transgressive marine mudstones. The structureless sandstones, previously interpreted as a glacial rock flour or loessite derived from the underlying undisturbed sandstones, differ significantly from typical loessite and contain hitherto unrecognised sedimentary structures, including hummocky cross-stratification. The sandstones, which grade laterally and vertically into stratigraphically equivalent undeformed marginal marine sandstones, are interpreted as a deformed facies of the underlying sandstones, deposited in a similar high energy shoreface environment. Although deformation of the shoreface sandstones was post-depositional, the origin of the deformation, and its confinement to the Jebel Ammar area is unknown. Deformation due to the weight of the overlying ice is unlikely as the glaciofluvial channels are now thought to have been cut by tunnel valley activity not ice. A more likely mechanism is post-glacial crustal tectonics. Melting of ice caps is commonly associated with intraplate seismicity and the development of an extensional crustal stress regime around the perimeter of ice caps; the interior is largely aseismic because the weight of the ice supresses seismic activity and faulting. Since southern Jordan lay close to the ice cap in Saudi Arabia it may have been subjected to postglacial seismicity and crustal stress, which induced ground shaking, reduced overburden pressure, increased hydrostatic pressure and possibly reactivation of existing tectonic faults. This resulted in liquefaction and extensive deformation of the sediments, which show many characteristics of seismites, generated by earthquake shocks. Since the glaciation was a very short-lived event (0.2-1 Ma), deglaciation and associated tectonism triggering deformation, lasted not more than a few hundred thousand years. Deglaciation and crustal unloading commonly lead to seismically-induced reactivation of tectonic faults. This relationship provides a possible explanation for the localisation of the deformation to the Jebel Ammar area which lies on the footwall of the Hutayya graben. The fault may also have acted as a conduit for post-seismic fluid movement along the fault plane under high pressure, thereby enhancing permeability and promoting fluid migration.

Post-glacial variability of sea ice cover, river run-off and biological production in the western Laptev Sea (Arctic Ocean) - A high-resolution biomarker study

NASA Astrophysics Data System (ADS)

Hörner, T.; Stein, R.; Fahl, K.; Birgel, D.

2016-07-01

Multi-proxy biomarker measurements were applied on two sediment cores (PS51/154, PS51/159) to reconstruct sea ice cover (IP25), biological production (brassicasterol, dinosterol) and river run-off (campesterol, β-sitosterol) in the western Laptev Sea over the last ∼17 ka with unprecedented temporal resolution. The absence of IP25 from 17.2 to 15.5 ka, in combination with minimum concentration of phytoplankton biomarkers, suggests that the western Laptev Sea shelf was mostly covered with permanent sea ice. Very minor river run-off and restricted biological production occurred during this cold interval. From ∼16 ka until 7.5 ka, a long-term decrease of terrigenous (riverine) organic matter and a coeval increase of marine organic matter reflect the gradual establishment of fully marine conditions in the western Laptev Sea, caused by the onset of the post-glacial transgression. Intensified river run-off and reduced sea ice cover characterized the time interval between 15.2 and 12.9 ka, including the Bølling/Allerød warm period (14.7-12.9 ka). Prominent peaks of the DIP25 Index coinciding with maximum abundances of subpolar foraminifers, are interpreted as pulses of Atlantic water inflow on the western Laptev Sea shelf. After the warm period, a sudden return to severe sea ice conditions with strongest ice-coverage between 11.9 and 11 ka coincided with the Younger Dryas (12.9-11.6 ka). At the onset of the Younger Dryas, a distinct alteration of the ecosystem (reflected in a distinct drop in terrigenous and phytoplankton biomarkers) was detected. During the last 7 ka, the sea ice proxies reflect a cooling of the Laptev Sea spring/summer season. This cooling trend was superimposed by a short-term variability in sea ice coverage, probably representing Bond cycles (1500 ± 500 ka) that are related to solar activity changes. Hence, atmospheric circulation changes were apparently able to affect the sea ice conditions on the Laptev Sea shelf under modern sea level conditions.

Climate Change and Genetic Structure of Leading Edge and Rear End Populations in a Northwards Shifting Marine Fish Species, the Corkwing Wrasse (Symphodus melops).

PubMed

Knutsen, Halvor; Jorde, Per Erik; Gonzalez, Enrique Blanco; Robalo, Joana; Albretsen, Jon; Almada, Vitor

2013-01-01

One mechanism by which marine organisms may respond to climate shifts is range shifts. The corkwing wrasse (Symphodus melops) is a temperate fish species, inhabiting the coasts of Europe, that show strong indications of current as well as historical (ice-age) range shifts towards the north. Nine neutral microsatellite DNA markers were screened to study genetic signatures and spatial population structure over the entire geographic and thermal gradient of the species from Portugal to Norway. A major genetic break (F ST  = 0.159 average among pairs) was identified between Scandinavian and more southern populations, with a marked reduction (30% or more) in levels of genetic variability in Scandinavia. The break is probably related to bottleneck(s) associated with post-glacial colonization of the Scandinavian coasts, and indicates a lack of present gene flow across the North Sea. The lack of gene flow can most likely be attributed to the species' need for rocky substrate for nesting and a relatively short pelagic larval phase, limiting dispersal by ocean currents. These findings demonstrate that long-distance dispersal may be severely limited in the corkwing wrasse, and that successful range-shifts following present climate change may be problematic for this and other species with limited dispersal abilities, even in the seemingly continuous marine environment.

Pools and fluxes of organic matter in a boreal landscape: implications for a safety assessment of a repository for nuclear waste.

PubMed

Kumblad, Linda; Söderbäck, Björn; Löfgren, Anders; Lindborg, Tobias; Wijnbladh, Erik; Kautsky, Ulrik

2006-12-01

To provide information necessary for a license application for a deep repository for spent nuclear fuel, the Swedish Nuclear Fuel and Waste Management Co is carrying out site investigations, including extensive studies of different parts of the surface ecosystems, at two sites in Sweden. Here we use the output from detailed modeling of the carbon dynamics in the terrestrial, limnic and marine ecosystems to describe and compare major pools and fluxes of organic matter in the Simpevarp area, situated on the southeast coast of Sweden. In this study, organic carbon is used as a proxy for radionuclides incorporated into organic matter. The results show that the largest incorporation of carbon into living tissue occurs in terrestrial catchments. Carbon is accumulated in soil or sediments in all ecosystems, but the carbon pool reaches the highest values in shallow near-land marine basins. The marine basins, especially the outer basins, are dominated by large horizontal water fluxes that transport carbon and any associated contaminants into the Baltic Sea. The results suggest that the near-land shallow marine basins have to be regarded as focal points for accumulation of radionuclides in the Simpevarp area, as they receive a comparatively large amount of carbon as discharge from terrestrial catchments, having a high NPP and a high detrital accumulation in sediments. These focal points may constitute a potential risk for exposure to humans in a future landscape as, due to post-glacial land uplift, previous accumulation bottoms are likely to be used for future agricultural purposes.

The kelp highway hypothesis: marine ecology, the coastal migration theory, and the peopling of the Americas

USGS Publications Warehouse

Erlandson, Jon M.; Graham, Michael H.; Bourque, Bruce J.; Corbett, Debra; Estes, James A.; Steneck, Robert S.

2007-01-01

In this article, a collaborative effort between archaeologists and marine ecologists, we discuss the role kelp forest ecosystems may have played in facilitating the movement of maritime peoples from Asia to the Americas near the end of the Pleistocene. Growing in cool nearshore waters along rocky coastlines, kelp forests offer some of the most productive habitats on earth, with high primary productivity, magnified secondary productivity, and three-dimensional habitat supporting a diverse array of marine organisms. Today, extensive kelp forests are found around the North Pacific from Japan to Baja California. After a break in the tropicswhere nearshore mangrove forests and coral reefs are highly productivekelp forests are also found along the Andean Coast of South America. These Pacific Rim kelp forests support or shelter a wealth of shellfish, fish, marine mammals, seabirds, and seaweeds, resources heavily used historically by coastal peoples. By about 16,000 years ago, the North Pacific Coast offered a linear migration route, essentially unobstructed and entirely at sea level, from northeast Asia into the Americas. Recent reconstructions suggest that rising sea levels early in the postglacial created a highly convoluted and island-rich coast along Beringia's southern shore, conditions highly favorable to maritime hunter-gatherers. Along with the terrestrial resources available in adjacent landscapes, kelp forests and other nearshore habitats sheltered similar suites of food resources that required minimal adaptive adjustments for migrating coastal peoples. With reduced wave energy, holdfasts for boats, and productive fishing, these linear kelp forest ecosystems may have provided a kind of kelp highway for early maritime peoples colonizing the New World.

Holocene palaeoenvironmental history of the Amazonian mangrove belt

NASA Astrophysics Data System (ADS)

Cohen, Marcelo Cancela Lisboa; Pessenda, Luiz Carlos Ruiz; Behling, Hermann; de Fátima Rossetti, Dilce; França, Marlon Carlos; Guimarães, José Tasso Felix; Friaes, Yuri; Smith, Clarisse Beltrão

2012-11-01

Wetland dynamic in the northern Brazilian Amazon region during the Holocene was reviewed using palynological, carbon and nitrogen isotopes records, and C/N ratio previously published. The integration of 72 radiocarbon dates recorded in 34 sediment cores sampled along the marine and fluvial littoral, and mainly influenced by the Amazon River, reveals that marine influence and mangrove vegetation were wider than today on the mouth of Amazon River between >8990-8690 and 2300-2230 cal yr BP, forming a continuous mangrove belt along the northern Brazilian Amazon littoral. The establishment of this mangrove strip is a direct consequence of the marine incursion caused by post-glacial sea-level rise possibly associated with tectonic subsidence during the Early and Middle Holocene. In the Late Holocene, in areas influenced by the Amazon River discharge, the mangroves were replaced by freshwater vegetation, and the coast morphology evolved from an estuarine dominated into a rectilinear coast due to coastal progradation. Nevertheless, the marine-influenced littoral, which is currently dominated by mangroves and salt-marsh vegetation, has persistently had brackish water vegetation over tidal mud flats throughout the entire Holocene. Likely, the fragmentation of this continuous mangrove line during the Late Holocene was caused by the increase of river freshwater discharge associated to the change from dry into wet climates in the Late Holocene. This caused a significant decrease of tidal water salinity in areas near the mouth of Amazon River. These changes in the Amazon discharge are probably associated with dry and wet periods in the northern Amazon region during the Holocene.

33 CFR 100.1304 - Annual Seattle Yacht Club's “Opening Day” Marine Parade.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Annual Seattle Yacht Club's âOpening Dayâ Marine Parade. 100.1304 Section 100.1304 Navigation and Navigable Waters COAST GUARD... Annual Seattle Yacht Club's “Opening Day” Marine Parade. (a) Regulated area. All of Portage Bay, with the...

Similarity of vegetation dynamics during interglacial periods

PubMed Central

Cheddadi, Rachid; de Beaulieu, Jacques-Louis; Jouzel, Jean; Andrieu-Ponel, Valérie; Laurent, Jeanne-Marine; Reille, Maurice; Raynaud, Dominique; Bar-Hen, Avner

2005-01-01

The Velay sequence (France) provides a unique, continuous, palynological record spanning the last four climatic cycles. A pollen-based reconstruction of temperature and precipitation displays marked climatic cycles. An analysis of the climate and vegetation changes during the interglacial periods reveals comparable features and identical major vegetation successions. Although Marine Isotope Stage (MIS) 11.3 and the Holocene had similar earth precessional variations, their correspondence in terms of vegetation dynamics is low. MIS 9.5, 7.5, and especially 5.5 display closer correlation to the Holocene than MIS 11.3. Ecological factors, such as the distribution and composition of glacial refugia or postglacial migration patterns, may explain these discrepancies. Comparison of ecosystem dynamics during the past five interglacials suggests that vegetation development in the current interglacial has no analogue from the past 500,000 years. PMID:16162676

The impact of Pleistocene glaciation across the range of a widespread European coastal species.

PubMed

Wilson, Anthony B; Eigenmann Veraguth, Iris

2010-10-01

There is a growing consensus that much of the contemporary phylogeography of northern hemisphere coastal taxa reflects the impact of Pleistocene glaciation, when glaciers covered much of the coastline at higher latitudes and sea levels dropped by as much as 150 m. The genetic signature of postglacial recolonization has been detected in many marine species, but the effects of coastal glaciation are not ubiquitous, leading to suggestions that species may intrinsically differ in their ability to respond to the environmental change associated with glacial cycles. Such variation may indeed have a biological basis, but apparent differences in population structure among taxa may also stem from our heavy reliance on individual mitochondrial loci, which are strongly influenced by stochasticity during coalescence. We investigated the contemporary population genetics of Syngnathus typhle, one of the most widespread European coastal fish species, using a multilocus data set to investigate the influence of Pleistocene glaciation and reduced sea levels on its phylogeography. A strong signal of postglacial recolonization was detected at both the northern and eastern ends of the species' distribution, while southern populations appear to have been relatively unaffected by the last glacial cycle. Patterns of population variation and differentiation at nuclear and mitochondrial loci differ significantly, but simulations indicate that these differences can be explained by the stochastic nature of the coalescent process. These results demonstrate the strength of a multilocus approach to phylogeography and suggest that an overdependence on mitochondrial loci may provide a misleading picture of population-level processes. © 2010 Blackwell Publishing Ltd.

Postglacial expansion pathways of red mangrove, Rhizophora mangle, in the Caribbean Basin and Florida.

PubMed

Kennedy, John Paul; Pil, Maria W; Proffitt, C Edward; Boeger, Walter A; Stanford, Alice M; Devlin, Donna J

2016-02-01

The Last Glacial Maximum (LGM) was a period of massive range contraction. Post-LGM, water-dispersed coastal species, including the red mangrove (Rhizophora mangle), expanded poleward as propagules were transported by ocean currents. We assessed postglacial marine expansion pathways for R. mangle within the Caribbean Basin and Florida. Six microsatellite loci were used to genotype 237 individuals from nine R. mangle populations in the Caribbean, Florida, and Northwest Africa. We evaluated genetic variation, population structure, gene flow along alternative post-LGM expansion pathways to Florida, and potential long-distance dispersal (LDD) from West Africa to Caribbean islands. These R. mangle populations had substantial genetic structure (FST = 0.37, P < 0.0001) with three discrete population clusters (Caribbean mainland, Caribbean islands, and Florida). Genetic connectivity along the mainland pathway (Caribbean mainland to Florida) vs. limited gene dispersal along the Antilles Island pathway (Caribbean islands to Florida) supported Florida recolonization from Caribbean mainland sources. Genetic similarity of Northwest Africa and two Caribbean islands provided evidence for trans-Atlantic LDD. We did not find a pattern of decreasing genetic diversity with latitude. We outline a complex expansion history for R. mangle, with discrete pathways of recolonization for Florida and Caribbean islands. Contrary to expectation, connectivity to putative Caribbean mainland refugial populations via ocean currents, and not latitude, appears to dictate genetic diversity within Caribbean island and Florida R. mangle. These findings provide a framework for further investigation of additional water-dispersed neotropical species, and insights for management initiatives. © 2016 Botanical Society of America.

Postglacial rebound and fault instability in Fennoscandia

NASA Astrophysics Data System (ADS)

Wu, Patrick; Johnston, Paul; Lambeck, Kurt

1999-12-01

The best available rebound model is used to investigate the role that postglacial rebound plays in triggering seismicity in Fennoscandia. The salient features of the model include tectonic stress due to spreading at the North Atlantic Ridge, overburden pressure, gravitationally self-consistent ocean loading, and the realistic deglaciation history and compressible earth model which best fits the sea-level and ice data in Fennoscandia. The model predicts the spatio-temporal evolution of the state of stress, the magnitude of fault instability, the timing of the onset of this instability, and the mode of failure of lateglacial and postglacial seismicity. The consistency of the predictions with the observations suggests that postglacial rebound is probably the cause of the large postglacial thrust faults observed in Fennoscandia. The model also predicts a uniform stress field and instability in central Fennoscandia for the present, with thrust faulting as the predicted mode of failure. However, the lack of spatial correlation of the present seismicity with the region of uplift, and the existence of strike-slip and normal modes of current seismicity are inconsistent with this model. Further unmodelled factors such as the presence of high-angle faults in the central region of uplift along the Baltic coast would be required in order to explain the pattern of seismicity today in terms of postglacial rebound stress. The sensitivity of the model predictions to the effects of compressibility, tectonic stress, viscosity and ice model is also investigated. For sites outside the ice margin, it is found that the mode of failure is sensitive to the presence of tectonic stress and that the onset timing is also dependent on compressibility. For sites within the ice margin, the effect of Earth rheology is shown to be small. However, ice load history is shown to have larger effects on the onset time of earthquakes and the magnitude of fault instability.

Post-glacial phylogeography and evolution of a wide-ranging highly-exploited keystone forest tree, eastern white pine (Pinus strobus) in North America: single refugium, multiple routes.

PubMed

Zinck, John W R; Rajora, Om P

2016-03-02

Knowledge of the historical distribution and postglacial phylogeography and evolution of a species is important to better understand its current distribution and population structure and potential fate in the future, especially under climate change conditions, and conservation of its genetic resources. We have addressed this issue in a wide-ranging and heavily exploited keystone forest tree species of eastern North America, eastern white pine (Pinus strobus). We examined the range-wide population genetic structure, tested various hypothetical population history and evolutionary scenarios and inferred the location of glacial refugium and post-glacial recolonization routes. Our hypothesis was that eastern white pine survived in a single glacial refugium and expanded through multiple post-glacial recolonization routes. We studied the range-wide genetic diversity and population structure of 33 eastern white pine populations using 12 nuclear and 3 chloroplast microsatellite DNA markers. We used Approximate Bayesian Computation approach to test various evolutionary scenarios. We observed high levels of genetic diversity, and significant genetic differentiation (F ST = 0.104) and population structure among eastern white pine populations across its range. A south to north trend of declining genetic diversity existed, consistent with repeated founder effects during post-glaciation migration northwards. We observed broad consensus from nuclear and chloroplast genetic markers supporting the presence of two main post-glacial recolonization routes that originated from a single southern refugium in the mid-Atlantic plain. One route gave rise to populations at the western margin of the species' range in Minnesota and western Ontario. The second route gave rise to central-eastern populations, which branched into two subgroups: central and eastern. We observed minimal sharing of chloroplast haplotypes between recolonization routes but there was evidence of admixture between the western and west-central populations. Our study reveals a single southern refugium, two recolonization routes and three genetically distinguishable lineages in eastern white pine that we suggest to be treated as separate Evolutionarily Significant Units. Like many wide-ranging North American species, eastern white pine retains the genetic signatures of post-glacial recolonization and evolution, and its contemporary population genetic structure reflects not just the modern distribution and effects of heavy exploitation but also routes northward from its glacial refugium.

Overview of the Cestode fauna of European shrews of the genus Sorex with an exploration of historical processes in post-glacial Europe

USDA-ARS?s Scientific Manuscript database

The cestode fauna in shrews of the genus Sorex from the European region consists of seventeen species. Twelve cestode species have broad Palearctic distributions, three belong to the Western-Asian–European faunistic complex, and only two are endemic to the European zone. Postglacial expansion into ...

29 CFR 1917.21 - Open fires.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Open fires. 1917.21 Section 1917.21 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Marine Terminal Operations § 1917.21 Open fires. Open fires and fires in drums or...

29 CFR 1917.21 - Open fires.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Open fires. 1917.21 Section 1917.21 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Marine Terminal Operations § 1917.21 Open fires. Open fires and fires in drums or...

29 CFR 1917.21 - Open fires.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Open fires. 1917.21 Section 1917.21 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Marine Terminal Operations § 1917.21 Open fires. Open fires and fires in drums or...

29 CFR 1917.21 - Open fires.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Open fires. 1917.21 Section 1917.21 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Marine Terminal Operations § 1917.21 Open fires. Open fires and fires in drums or...

29 CFR 1917.21 - Open fires.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Open fires. 1917.21 Section 1917.21 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Marine Terminal Operations § 1917.21 Open fires. Open fires and fires in drums or...

50 CFR Figure 17 to Part 223 - Boone Wedge Cut Escape Opening

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Boone Wedge Cut Escape Opening 17 Figure 17 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt...

Geochemical climate proxies applied to the Neoproterozoic glacial succession on the Yangtze Platform, South China

NASA Astrophysics Data System (ADS)

Dobrzinski, Nicole; Bahlburg, Heinrich; Strauss, Harald; Zhang, Qirui

A Neoproterozoic succession of glaciomarine deposits of probably Sturtian age is preserved on the Yangtze Platform in South China. At that time, the South China block was located in intermediate to low paleolatitudes at ca. 40°. The snowball Earth hypothesis offers one possible explanation for the occurrence of low latitude tillites. The hypothesis is largely based on geological and geochemical observation made in deposits underlying or overlying such tillites on several continents. In contrast our study focuses on evidence offered by the tillites themselves. We use major, trace and rare earth geochemistry to evaluate the environmental conditions prevailing during the glaciation. Of particular interest are the intensity of chemical weathering and the relative degree of oxygenation of Neoproterozoic (Nanhuan-Sinian) marine bottom waters. CIA values were obtained from preglacial sand- and siltstones, the matrix of the glacial deposits, fine-grained clastic sediments of a unit intercalated in the glacial succession, and postglacial siltstones and black shales. The data indicate relatively low degrees of chemical weathering for the glacial deposits. In contrast, pre- and postglacial deposits display comparatively elevated levels. This is also true for the intercalated unit, which we interpret as the product of a warmer and more humid interglacial period. Data for S/TOC, U/Th, Cd, Mo, and the Ceanom of the glaciomarine samples indicate the presence of oxic bottom waters during the glaciation. The snowball Earth hypothesis predicts the shutdown of chemical weathering on the continents and complete anoxia of the global ocean largely covered by sea ice for several million years. The geochemical record of the Neoproterozoic tillites on the Yangtze Platform is difficult to reconcile with the snowball Earth hypothesis.

Contrasting patterns of genetic diversity across the ranges of Pinus monticola and P. strobus: a comparison between eastern and western North American postglacial colonization histories.

PubMed

Nadeau, Simon; Godbout, Julie; Lamothe, Manuel; Gros-Louis, Marie-Claude; Isabel, Nathalie; Ritland, Kermit

2015-08-01

• Premises of the study: Understanding the influence of recent glacial and postglacial periods on species' distributions is key for predicting the effects of future environmental changes. We investigated the influence of two physiographic landscapes on population structure and postglacial colonization of two white pine species of contrasting habitats: P. monticola, which occurs in the highly mountainous region of western North America, and P. strobus, which occurs in a much less mountainous area in eastern North America.• To characterize the patterns of genetic diversity and population structure across the ranges of both species, 158 and 153 single nucleotide polymorphism (SNP) markers derived from expressed genes were genotyped on range-wide samples of 61 P. monticola and 133 P. strobus populations, respectively.• In P. monticola, a steep latitudinal decrease in genetic diversity likely resulted from postglacial colonization involving rare long-distance dispersal (LDD) events. In contrast, no geographic patterns of diversity were detected in P. strobus, suggesting recolonization via a gradually advancing front or frequent LDD events. For each species, structure analyses identified two distinct southern and northern genetic groups that likely originated from two different glacial lineages. At a finer scale, and for the two species, smaller subgroups were detected that could be remnants of cryptic refugia.• During postglacial colonization, the western and eastern North American landscapes had different impacts on genetic signatures in P. monticola compared with P. strobus. We discuss the importance of our findings for conservation programs and predictions of species' response to climate change. © 2015 Her Majesty the Queen in Right of Canada. Published by the Botanical Society of America.

50 CFR Figure 13 to Part 223 - Single Grid Hard TED Escape Opening

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Single Grid Hard TED Escape Opening 13 Figure 13 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt...

50 CFR Figure 12 to Part 223 - Escape Opening & Cover Dimensions for 71-inch TED

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Escape Opening & Cover Dimensions for 71-inch TED 12 Figure 12 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND...

50 CFR Figure 13 to Part 223 - Single Grid Hard TED Escape Opening

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Single Grid Hard TED Escape Opening 13 Figure 13 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt...

50 CFR Figure 12 to Part 223 - Escape Opening & Cover Dimensions for 71-inch TED

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Escape Opening & Cover Dimensions for 71-inch TED 12 Figure 12 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND...

Postglacial migration supplements climate in determining plant species ranges in Europe

PubMed Central

Normand, Signe; Ricklefs, Robert E.; Skov, Flemming; Bladt, Jesper; Tackenberg, Oliver; Svenning, Jens-Christian

2011-01-01

The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to postglacial colonization. Climate was important for all species, while postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role. PMID:21543356

Postglacial recolonization in a cold climate specialist in western Europe: patterns of genetic diversity in the adder (Vipera berus) support the central-marginal hypothesis.

PubMed

Ursenbacher, Sylvain; Guillon, Michaël; Cubizolle, Hervé; Dupoué, Andréaz; Blouin-Demers, Gabriel; Lourdais, Olivier

2015-07-01

Understanding the impact of postglacial recolonization on genetic diversity is essential in explaining current patterns of genetic variation. The central-marginal hypothesis (CMH) predicts a reduction in genetic diversity from the core of the distribution to peripheral populations, as well as reduced connectivity between peripheral populations. While the CMH has received considerable empirical support, its broad applicability is still debated and alternative hypotheses predict different spatial patterns of genetic diversity. Using microsatellite markers, we analysed the genetic diversity of the adder (Vipera berus) in western Europe to reconstruct postglacial recolonization. Approximate Bayesian Computation (ABC) analyses suggested a postglacial recolonization from two routes: a western route from the Atlantic Coast up to Belgium and a central route from the Massif Central to the Alps. This cold-adapted species likely used two isolated glacial refugia in southern France, in permafrost-free areas during the last glacial maximum. Adder populations further from putative glacial refugia had lower genetic diversity and reduced connectivity; therefore, our results support the predictions of the CMH. Our study also illustrates the utility of highly variable nuclear markers, such as microsatellites, and ABC to test competing recolonization hypotheses. © 2015 John Wiley & Sons Ltd.

Cr isotope stratigraphy of Ediacaran cap dolostones, Doushantuo Formation, South China

NASA Astrophysics Data System (ADS)

Rodler, Alexandra; Hohl, Simon V.; Guo, Qingjun; Frei, Robert

2016-04-01

The Yangtze Platform in South China is considered a key site for studying Neoproterozoic ocean oxygenation. The chromium isotope composition (δ53Cr) of marine carbonates has shown to be a sensitive tracer of changing (paleo)redox conditions and was previously linked to photosynthetic activity (1). We applied this emerging proxy to cap dolostones of a deep water and a shallow marine carbonate section pertaining to the Doushantuo Formation that have previously been used to constrain the redox evolution of Ediacaran seawater (2,3). Postglacial detrital contamination and diagenetic alteration appear to have influenced the δ53Cr values of Doushantuo cap dolostones as evidenced by systematic changes in δ53Cr and Cr concentrations coupled with several geochemical tracers. We use Al concentrations as indicator of detrital contamination and to calculate the authigenic Cr isotope composition. Further, we hypothesis that post-depositional remobilization of Cr might have resulted in the loss of heavy Cr isotopes and the retention of light Cr isotopes during precipitation of secondary carbonates. This scenario is supported by a decrease in δ53Cr values that is correlated with a loss of Sr and increasingly light δ18Ocarb signals, which would indicate meteoric fluid/rock interaction and diagenetic alteration by continental basin fluids. However, some cap dolostones may still show pristine Ediacaran seawater signals with positively fractionated δ53Cr (relative to bulk silicate Earth; 4), 87Sr/86Sr close to Ediacaran seawater values and a pronounced negative Ce anomaly. These tracers reveal light pulses of enhanced postglacial oxidative weathering during cap dolostone deposition. The Cr isotope composition of Ediacaran cap dolostones pertaining to the Doushantuo Formation trace changes in past redox conditions, where fine-scale δ53Cr fluctuations are perhaps a result of detrital contamination and diagenetic alteration balanced against a signal of oxidative weathering. Although, a careful assessment of detrital contamination and diagenetic alteration is necessary, we propose that using the stable Cr isotope system can provide valuable information and further enhance our understanding of Neoproterozoic ocean oxygenation, past weathering regimes as well as past climate and environmental changes. References: (1) Frei et al. (2011) EPSL 312, 114-125. (2) Guo et al. (2007) Palaeogeogr. Palaeoclimatol. Palaeoecol. 254, 140-157. (3) Hohl et al. (2015) GCA 163, 262-278. (4) Schoenberg et al. (2008) Chem. Geology 249, 294-306.

78 FR 51147 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-20

... monitoring systems; and (5) exacting funds from TGS to support accelerated mitigation research in this area... (2D) seismic survey program in the Chukchi Sea, Alaska, during the 2013 Arctic open-water season... small numbers of marine mammals incidental to conducting an open-water 2D seismic survey in the Chukchi...

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE...

33 CFR 100.1304 - Annual Seattle Yacht Club's “Opening Day” Marine Parade.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Annual Seattle Yacht Club's âOpening Dayâ Marine Parade. 100.1304 Section 100.1304 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.1304...

Correction to “Changes in the Earth's rotation by tectonic movements”

NASA Astrophysics Data System (ADS)

Vermeersen, L. L. A.; Vlaar, N. J.

1993-06-01

Present-day true polar wander and the secular non-tidal acceleration of the earth are usually attributed to post-glacial rebound. In the models which relate this rebound to changes in rotation, the mantle is assumed to relax passively to the melted ice-loads. The lithosphere is usually modeled as a highly viscous upper layer in these models, having viscosities which exceed mantle viscosities by several orders of magnitude. We propose that lithospheric processes unrelated to post-glacial rebound and taking place under non-isostatic conditions are also able to induce non-negligible influences on the earth's rotation. Examples of such processes are mountain building and erosion, foundering flexure of oceanic basins and lithospheric snapbacking resulting from detachment of subducting slabs. Lithospheric and crustal rheologies and intraplate-stresses are the dominant factors in these mechanisms, contrary to the mantle rheologies which are assumed to dominate the process of post-glacial rebound.

50 CFR Figure 12 to Part 223 - Escape Opening & Cover Dimensions for 71-inch TED

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Escape Opening & Cover Dimensions for 71-inch TED 12 Figure 12 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 12 Figure 12 to...

50 CFR Figure 13 to Part 223 - Single Grid Hard TED Escape Opening

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Single Grid Hard TED Escape Opening 13 Figure 13 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 13 Figure 13 to Part 223—Singl...

Delineation of a quick clay zone at Smørgrav, Norway, with electromagnetic methods under geotechnical constraints

NASA Astrophysics Data System (ADS)

Kalscheuer, Thomas; Bastani, Mehrdad; Donohue, Shane; Persson, Lena; Aspmo Pfaffhuber, Andreas; Reiser, Fabienne; Ren, Zhengyong

2013-05-01

In many coastal areas of North America and Scandinavia, post-glacial clay sediments have emerged above sea level due to iso-static uplift. These clays are often destabilised by fresh water leaching and transformed to so-called quick clays as at the investigated area at Smørgrav, Norway. Slight mechanical disturbances of these materials may trigger landslides. Since the leaching increases the electrical resistivity of quick clay as compared to normal marine clay, the application of electromagnetic (EM) methods is of particular interest in the study of quick clay structures. For the first time, single and joint inversions of direct-current resistivity (DCR), radiomagnetotelluric (RMT) and controlled-source audiomagnetotelluric (CSAMT) data were applied to delineate a zone of quick clay. The resulting 2-D models of electrical resistivity correlate excellently with previously published data from a ground conductivity metre and resistivity logs from two resistivity cone penetration tests (RCPT) into marine clay and quick clay. The RCPT log into the central part of the quick clay identifies the electrical resistivity of the quick clay structure to lie between 10 and 80 Ω m. In combination with the 2-D inversion models, it becomes possible to delineate the vertical and horizontal extent of the quick clay zone. As compared to the inversions of single data sets, the joint inversion model exhibits sharper resistivity contrasts and its resistivity values are more characteristic of the expected geology. In our preferred joint inversion model, there is a clear demarcation between dry soil, marine clay, quick clay and bedrock, which consists of alum shale and limestone.

Submarine glaciated landscapes of central and northern British Columbia, Canada

NASA Astrophysics Data System (ADS)

Shaw, John; Lintern, Gwyn

2015-04-01

Recent systematic multibeam sonar mapping and ground-truthing surveys in the fjords and coastal waters of central and northern British Columbia, Canada, provide information on glacial processes associated with the Cordilleran Ice Sheet, and also on postglacial processes that have strongly modified the glacial terrain. During the last glacial maximum, ice covered the Coast Range, except for nunataks. Convergent streamlined glacial landforms in the Strait of Georgia testify to a strong flow of ice towards the southeast, between Vancouver Island and the mainland. During ice retreat, thick deposits of acoustically stratified glaciomarine mud were deposited in glacially over deepened basins. Retreat through the Douglas Channel fjord system was punctuated by still stands, resulting in a series of submarine moraines. Postglacial processes have created a suite of landforms that mask the primary glacial terrain: 1) Fjord floors host thick deposits of acoustically transparent postglacial mud with highly variable distribution: banks up to 80-m thick are commonly adjacent to erosional zones with glaciomarine mud exposed at the seafloor; 2) In this region of high precipitation and snowpack melt, numerous cone-shaped Holocene fan deltas developed on the fjord sidewalls transport coarse sediment to the fjord floors. Larger deltas are developed at fjord heads, notably at Kitimat and Kildala; 3) Submarine slope failures in this tectonically active area have resulted in a suite of mass transport deposits on sidewalls and fjord floors. The very large submarine slope failures at Camano Sound and KitKat Inlet occurred on the steep, rear facets of large transverse moraines, and involved the failure of glaciomarine sediment that moved into deeper basins, perhaps as a retrogressive failure. The ages of these events are unknown, although the presence of postglacial mud in the slide scar at Caamano suggests that the event at that location occurred in the late glacial or early Holocene. Also, sub-bottom profiling shows that some mass transport deposits apparent on the multibeam imagery are not recent, and are blanketed by postglacial mud. Thus, submarine slope failure has been occurring throughout postglacial time; 4) Large, detached bedrock blocks on the fjord sidewall are currently being investigated with a view to understanding their rates of movement. They are provisionally interpreted as creep features, similar to terrestrial sackung.

Changes in the earth's rotation by tectonic movements

NASA Astrophysics Data System (ADS)

Vermeersen, L. L. A.; Vlaar, N. J.

1993-01-01

We propose that lithospheric processes unrelated to postglacial rebound and taking place under nonisostatic conditions are able to induce nonnegligible influences on the earth's rotation. Examples of such processes are mountain building and erosion, foundering flexure of oceanic basins and lithospheric snapbacking resulting from detachment of subducting slabs. Lithospheric and crustal rheologies and intraplate stresses are the dominant factors in these mechanisms, contrary to the mantle rheologies which are assumed to dominate the process of postglacial rebound.

National Weather Service Marine Text Forecasts

Science.gov Websites

Offshore NAVTEX Bay and Coastal Surf Zone Recreational Marine Weather Statements Special Marine Warnings Marine Weather Messages Alaska Bay and Coastal Great Lakes Open Lake Great Lakes Nearshore Great Lakes

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 1...

The impact of water loading on postglacial decay times in Hudson Bay

NASA Astrophysics Data System (ADS)

Han, Holly Kyeore; Gomez, Natalya

2018-05-01

Ongoing glacial isostatic adjustment (GIA) due to surface loading (ice and water) variations during the last glacial cycle has been contributing to sea-level changes globally throughout the Holocene, especially in regions like Canada that were heavily glaciated during the Last Glacial Maximum (LGM). The spatial and temporal distribution of GIA, as manifested in relative sea-level (RSL) change, are sensitive to the ice history and the rheological structure of the solid Earth, both of which are uncertain. It has been shown that RSL curves near the center of previously glaciated regions with no ongoing surface loading follow an exponential-like form, with the postglacial decay times associated with that form having a weak sensitivity to the details of the ice loading history. Postglacial decay time estimates thus provide a powerful datum for constraining the Earth's viscous structure and improving GIA predictions. We explore spatial patterns of postglacial decay time predictions in Hudson Bay by decomposing numerically modeled RSL changes into contributions from water and ice loading effects, and computing their relative impact on the decay times. We demonstrate that ice loading can contribute a strong geographic trend on the decay time estimates if the time window used to compute decay times includes periods that are temporally close to (i.e. contemporaneous with, or soon after) periods of active loading. This variability can be avoided by choosing a suitable starting point for the decay time window. However, more surprisingly, we show that across any adopted time window, water loading effects associated with inundation into, and postglacial flux out of, Hudson Bay and James Bay will impart significant geographic variability onto decay time estimates. We emphasize this issue by considering both maps of predicted decay times across the region and site-specific estimates, and we conclude that variability in observed decay times (whether based on existing or future data sets) may reflect this water loading signal.

Active Neotectonic Structures in Glacial and Postglacial Sediment in Lake Timiskaming, Timiskaming Graben, Ontario/Quebec Canada

NASA Astrophysics Data System (ADS)

Doughty, M.; Eyles, N.; Eyles, C.

2009-05-01

The Timiskaming Graben (TG) is a northwest-trending arm of the Ottawa-Bonnechere Graben and the St. Lawrence Rift System (SLRS) in eastern Canada. Together they form a 600 km long failed rift in the Canadian Shield, extending southward along the border of Ontario and Quebec to the St.Lawrence River Valley onto the Hudson Valley and Lake Champlain in the USA. The Timiskaming Graben preserves faulted outliers of Early Paleozoic limestones and has been reactivated several time during the Phanerozoic most recently during the breakup of Pangea. The 110 kilometre-long, ~100 m deep Lake Timiskaming fills the inner part of the Timiskaming Graben along the border of Ontario and Quebec. It is the postglacial successor to glacial Lake Barlow ponded against the northward-retreating Laurentide Ice Sheet some 9,000 years BP. The sedimentary record of Lake Timiskaming was established by collecting more than 1000 line kilometres of high-resolution 'chirp' seismic profiles, side scan and multibeam survey data between 2003 and 2007. These show that bathymetric relief is the product of ongoing tectonic subsidence where lateglacial Barlow glaciolacustrine and postglacial sediments are extensively deformed by closely-spaced horst and grabens. The greatest subsidence has occurred within a narrow (< 3 km) and deep (up to 209 m) central graben basin. We are able to infer the presence of hitherto unrecognized bounding and relay faults within the graben, and a 20 km long 8 m high fault scarp and sand blows produced by large postglacial earthquakes. The region is one of the most seismically active areas in eastern North America (Western Quebec Seismic Zone) with frequent moderate to large magnitude (> M5) intracratonic earthquakes. Structural activity is ongoing along the Timiskaming Graben and its lateglacial and postglacial sediment record provides the clearest evidence to date of modern intracratonic faulting anywhere in eastern North America.

Postglacial viability and colonization in North America’s ice-free corridor

NASA Astrophysics Data System (ADS)

Pedersen, Mikkel W.; Ruter, Anthony; Schweger, Charles; Friebe, Harvey; Staff, Richard A.; Kjeldsen, Kristian K.; Mendoza, Marie L. Z.; Beaudoin, Alwynne B.; Zutter, Cynthia; Larsen, Nicolaj K.; Potter, Ben A.; Nielsen, Rasmus; Rainville, Rebecca A.; Orlando, Ludovic; Meltzer, David J.; Kjær, Kurt H.; Willerslev, Eske

2016-09-01

During the Last Glacial Maximum, continental ice sheets isolated Beringia (northeast Siberia and northwest North America) from unglaciated North America. By around 15 to 14 thousand calibrated radiocarbon years before present (cal. kyr BP), glacial retreat opened an approximately 1,500-km-long corridor between the ice sheets. It remains unclear when plants and animals colonized this corridor and it became biologically viable for human migration. We obtained radiocarbon dates, pollen, macrofossils and metagenomic DNA from lake sediment cores in a bottleneck portion of the corridor. We find evidence of steppe vegetation, bison and mammoth by approximately 12.6 cal. kyr BP, followed by open forest, with evidence of moose and elk at about 11.5 cal. kyr BP, and boreal forest approximately 10 cal. kyr BP. Our findings reveal that the first Americans, whether Clovis or earlier groups in unglaciated North America before 12.6 cal. kyr BP, are unlikely to have travelled by this route into the Americas. However, later groups may have used this north-south passageway.

Postglacial viability and colonization in North America's ice-free corridor.

PubMed

Pedersen, Mikkel W; Ruter, Anthony; Schweger, Charles; Friebe, Harvey; Staff, Richard A; Kjeldsen, Kristian K; Mendoza, Marie L Z; Beaudoin, Alwynne B; Zutter, Cynthia; Larsen, Nicolaj K; Potter, Ben A; Nielsen, Rasmus; Rainville, Rebecca A; Orlando, Ludovic; Meltzer, David J; Kjær, Kurt H; Willerslev, Eske

2016-09-01

During the Last Glacial Maximum, continental ice sheets isolated Beringia (northeast Siberia and northwest North America) from unglaciated North America. By around 15 to 14 thousand calibrated radiocarbon years before present (cal. kyr bp), glacial retreat opened an approximately 1,500-km-long corridor between the ice sheets. It remains unclear when plants and animals colonized this corridor and it became biologically viable for human migration. We obtained radiocarbon dates, pollen, macrofossils and metagenomic DNA from lake sediment cores in a bottleneck portion of the corridor. We find evidence of steppe vegetation, bison and mammoth by approximately 12.6 cal. kyr bp, followed by open forest, with evidence of moose and elk at about 11.5 cal. kyr bp, and boreal forest approximately 10 cal. kyr bp. Our findings reveal that the first Americans, whether Clovis or earlier groups in unglaciated North America before 12.6 cal. kyr bp, are unlikely to have travelled by this route into the Americas. However, later groups may have used this north-south passageway.

Regional Geology of the Southern Lake Erie (Ohio) Bottom: A Seismic Reflection and Vibracore Study.

DTIC Science & Technology

1982-12-01

identify by block number) Geomorphology Sand resources Seismic reflection Lake Erie Sediments Vibracores Ohio 20. ABST’RACT (Cotfme -n 9e~re .ft if...postglacial deposit thicknesses range from 0 to 22 meters and like the till, the postglacial sediment thickens lakeward. The tills were first deposited on an...ihen Data Entered) PREFACE This report is one of three reports which describe results of the Inner Continental Shelf Sediment and Structure (ICONS

Connectivity of the habitat-forming kelp, Ecklonia radiata within and among estuaries and open coast.

PubMed

Coleman, Melinda A

2013-01-01

With marine protected areas being established worldwide there is a pressing need to understand how the physical setting in which these areas are placed influences patterns of dispersal and connectivity of important marine organisms. This is particularly critical for dynamic and complex nearshore marine environments where patterns of genetic structure of organisms are often chaotic and uncoupled from broad scale physical processes. This study determines the influence of habitat heterogeneity (presence of estuaries) on patterns of genetic structure and connectivity of the common kelp, Ecklonia radiata. There was no genetic differentiation of kelp between estuaries and the open coast and the presence of estuaries did not increase genetic differentiation among open coast populations. Similarly, there were no differences in level of inbreeding or genetic diversity between estuarine and open coast populations. The presence of large estuaries along rocky coastlines does not appear to influence genetic structure of this kelp and factors other than physical heterogeneity of habitat are likely more important determinants of regional connectivity. Marine reserves are currently lacking in this bioregion and may be designated in the future. Knowledge of the factors that influence important habitat forming organisms such as kelp contribute to informed and effective marine protected area design and conservation initiatives to maintain resilience of important marine habitats.

The Amazon at sea: Onset and stages of the Amazon River from a marine record, with special reference to Neogene plant turnover in the drainage basin

NASA Astrophysics Data System (ADS)

Hoorn, Carina; Bogotá-A, Giovanni R.; Romero-Baez, Millerlandy; Lammertsma, Emmy I.; Flantua, Suzette G. A.; Dantas, Elton L.; Dino, Rodolfo; do Carmo, Dermeval A.; Chemale, Farid

2017-06-01

The Amazon submarine fan is a large sediment apron situated offshore Pará (Brazil) and represents the most distal extent of the Amazon River. The age of onset of this transcontinental river remains debated, yet is of great importance for understanding biotic evolutionary processes on land and at sea. Here we present new geochemical and palynological data from a borehole drilled at the continental slope and dated based on nannofossil biostratigraphy. We found that sediments of mixed source (craton and adjacent) occur at least from the late Oligocene (NP25) to late Miocene (NN9), and that the earliest Andes-derived sediments occur in NN10 (late Miocene). Our geochemical record indicates an onset of the transcontinental Amazon River between 9.4 and 9 Ma, which postdates the regional unconformity by 1 to 1.5 My. The shift in sediment geochemistry is more gradually replicated in the palynological record by a change from coastal plain and tropical lowland taxa to a mixture of tropical lowland, and montane forest to open Andean taxa. In particular, the appearance of taxa such as Jamesonia and Huperzia, followed by Valeriana, Polylepis-Acaena, Lysipomia and Plantago (with a current altitudinal range from 3200 to 4000 m) suggests the development of open, treeless, vegetation between 9.5 and 5.4 Ma, and highlight the presence of a high Andes in the late Miocene hinterland. Poaceae progressively increased from 9 Ma, with a notable rise from 4 Ma onwards, and percentages well above post-glacial and modern values, particularly between 2.6 and 0.8 Ma. We hypothesize that the rise of the grasses is a basin-wide phenomenon, but that the Plio-Pleistocene expansion of open, treeless vegetation on the Andean slopes and foothills are the main contributor. This rise in grasses was likely caused by climatic fluctuations, and subsequent changes in relief and erosion rates. We conclude that the onset of the Amazon River is coupled with Neogene Andean tectonism and that subsequent developments, both of river and biota, are closely linked to the Plio-Pleistocene climatic fluctuations. From latest Neogene onwards these major landscape changes determined the composition of the montane and lowland forest in the Andes-Amazonian system.

Magnifying Democracy and Sovereignty In Indonesian Maritime Governance Through Open Marine Spatial Data Practice

NASA Astrophysics Data System (ADS)

Yudono, Adipandang

2018-05-01

This research has attempted to discover a new approach in magnifying democracy and sovereignty in the Indonesian maritime governance through open marine spatial data practices between governments and citizens. The research has been done in order to fill in the gap of bridging marine spatial data or information at all government levels and between citizen and government. The research predominantly used qualitative methods with specifically approach was discourse analysis using legal document analysis and in-depth interview to elites, and local digital mapping communities. The coherence and synergy of maritime development can be achieved through dialogue between the elites and the public. A solution to bridge political communication between the elite and the public is sharing or open marine spatial data and information.

Massive remobilization of permafrost carbon during post-glacial warming

PubMed Central

Tesi, T.; Muschitiello, F.; Smittenberg, R. H.; Jakobsson, M.; Vonk, J. E.; Hill, P.; Andersson, A.; Kirchner, N.; Noormets, R.; Dudarev, O.; Semiletov, I.; Gustafsson, Ö

2016-01-01

Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial–interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming. Thawing of PF-C must also have brought about an enhanced organic matter respiration and, thus, these findings suggest that PF-C may indeed have been an important source of CO2 across the extensive permafrost domain. The results challenge current paradigms on the post-glacial CO2 rise and, at the same time, serve as a harbinger for possible consequences of the present-day warming of PF-C soils. PMID:27897191

Massive remobilization of permafrost carbon during post-glacial warming

NASA Astrophysics Data System (ADS)

Tesi, T.; Muschitiello, F.; Smittenberg, R. H.; Jakobsson, M.; Vonk, J. E.; Hill, P.; Andersson, A.; Kirchner, N.; Noormets, R.; Dudarev, O.; Semiletov, I.; Gustafsson, Ö.

2016-11-01

Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial-interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming. Thawing of PF-C must also have brought about an enhanced organic matter respiration and, thus, these findings suggest that PF-C may indeed have been an important source of CO2 across the extensive permafrost domain. The results challenge current paradigms on the post-glacial CO2 rise and, at the same time, serve as a harbinger for possible consequences of the present-day warming of PF-C soils.

Fire and vegetation shifts in the Americas at the vanguard of Paleoindian migration

USGS Publications Warehouse

Pinter, N.; Fiedel, S.; Keeley, J.E.

2011-01-01

Across North and South America, the final millennia of the Pleistocene saw dramatic changes in climate, vegetation, fauna, fire regime, and other local and regional paleo-environmental characteristics. Rapid climate shifts following the Last Glacial Maximum (LGM) exerted a first-order influence, but abrupt postglacial shifts in vegetation composition, vegetation structure, and fire regime also coincided with human arrival and transformative faunal extinctions in the Americas. We propose a model of post-glacial vegetation change in response to climatic drivers, punctuated by local fire regime shifts in response to megaherbivore-driven fuel changes and anthropogenic ignitions. The abrupt appearance of humans, disappearance of megaherbivores, and resulting changes in New World fire systems were transformative events that should not be dismissed in favor of climate-only interpretations of post-glacial paleo-environmental shifts in the Americas. Fire is a mechanism by which small human populations can have broad impacts, and growing evidence suggests that early anthropogenic influences on regional, even global, paleo-environments should be tested alongside other potential causal mechanisms.

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES... MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 16 Figure 16 to Part 223—Escape Opening and Flap Dimensions...

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES... MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 16 Figure 16 to Part 223—Escape Opening and Flap Dimensions...

Quaternary geology of the Rhode Island inner shelf

USGS Publications Warehouse

Needell, S. W.; O'Hara, C. J.; Knebel, H.J.

1983-01-01

Five sedimentary units and three erosional unconformities identified in high-resolution seismic-reflection profiles reveal the stratigraphic framework and Quaternary history of the inner continental shelf south of Narragansett Bay, Rhode Island. Late Tertiary to early Pleistocene rivers eroded the pre-Mesozoic bedrock and the Upper Cretaceous to lower Tertiary coastal plain and continental shelf strata to form a lowland and cuesta having a north-facing escarpment. The lowland and landward flanks of the cuesta were modified by glaciers during Pleistocene time and subsequently were overlain by drift and end moraine deposits of the late Wisconsinan ice advance. During deglaciation, freshwater lakes formed between the retreating ice and end moraines. Prior to sea-level rise, the drift and older deposits were cut by streams flowing south and southwestward toward Block Island Sound. As sea level rose, postglacial valleys were partly filled by fluvial, freshwater-peat, estuarine and salt-marsh deposits. Transgressing seas eroded the sea floor, exposing bedrock and coastal plain outcrops, and deposited marine sediments. ?? 1983.

Fire responses to postglacial climate change and human impact in northern Patagonia (41-43°S).

PubMed

Iglesias, Virginia; Whitlock, Cathy

2014-12-23

Forest/steppe boundaries are among the most dynamic ecosystems on Earth and are highly vulnerable to changes in climate and land use. In this study we examine the postglacial history of the Patagonian forest/steppe ecotone (41-43°S) to better understand its sensitivity to past variations in climate, disturbance, and human activity before European colonization. We present regional trends in vegetation and biomass burning, as detected by generalized additive models fitted to seven pollen and charcoal records, and compare the results with other paleoenvironmental data, as well as archeological and ecological information to (i) estimate postglacial fire trends at regional scales, (ii) assess the evolution of climate-vegetation-fire linkages over the last 18,000 calibrated (cal) years B.P., and (iii) evaluate the role of humans in altering pre-European landscapes and fire regimes. Pollen and charcoal data indicate that biomass burning was relatively low during warm/dry steppe-dominated landscapes in the late glacial/Early Holocene transition and increased as more humid conditions favored forest development after ca. 10,000 cal years B.P. Postglacial fire activity was thus limited by fuel availability associated with sparse vegetation cover rather than by suitable climate conditions. In contrast to extensive burning by European settlers, variations in indigenous population densities were not associated with fluctuations in regional or watershed-scale fire occurrence, suggesting that climate-vegetation-fire linkages in northern Patagonia evolved with minimal or very localized human influences before European settlement.

Fire responses to postglacial climate change and human impact in northern Patagonia (41–43°S)

PubMed Central

Iglesias, Virginia; Whitlock, Cathy

2014-01-01

Forest/steppe boundaries are among the most dynamic ecosystems on Earth and are highly vulnerable to changes in climate and land use. In this study we examine the postglacial history of the Patagonian forest/steppe ecotone (41–43°S) to better understand its sensitivity to past variations in climate, disturbance, and human activity before European colonization. We present regional trends in vegetation and biomass burning, as detected by generalized additive models fitted to seven pollen and charcoal records, and compare the results with other paleoenvironmental data, as well as archeological and ecological information to (i) estimate postglacial fire trends at regional scales, (ii) assess the evolution of climate–vegetation–fire linkages over the last 18,000 calibrated (cal) years B.P., and (iii) evaluate the role of humans in altering pre-European landscapes and fire regimes. Pollen and charcoal data indicate that biomass burning was relatively low during warm/dry steppe-dominated landscapes in the late glacial/Early Holocene transition and increased as more humid conditions favored forest development after ca. 10,000 cal years B.P. Postglacial fire activity was thus limited by fuel availability associated with sparse vegetation cover rather than by suitable climate conditions. In contrast to extensive burning by European settlers, variations in indigenous population densities were not associated with fluctuations in regional or watershed-scale fire occurrence, suggesting that climate–vegetation–fire linkages in northern Patagonia evolved with minimal or very localized human influences before European settlement. PMID:25489077

Patterns of Post-Glacial Genetic Differentiation in Marginal Populations of a Marine Microalga

PubMed Central

Tahvanainen, Pia; Alpermann, Tilman J.; Figueroa, Rosa Isabel; John, Uwe; Hakanen, Päivi; Nagai, Satoshi; Blomster, Jaanika; Kremp, Anke

2012-01-01

This study investigates the genetic structure of an eukaryotic microorganism, the toxic dinoflagellate Alexandrium ostenfeldii, from the Baltic Sea, a geologically young and ecologically marginal brackish water estuary which is predicted to support evolution of distinct, genetically impoverished lineages of marine macroorganisms. Analyses of the internal transcribed spacer (ITS) sequences and Amplified Fragment Length Polymorphism (AFLP) of 84 A. ostenfeldii isolates from five different Baltic locations and multiple external sites revealed that Baltic A. ostenfeldii is phylogenetically differentiated from other lineages of the species and micro-geographically fragmented within the Baltic Sea. Significant genetic differentiation (F ST) between northern and southern locations was correlated to geographical distance. However, instead of discrete genetic units or continuous genetic differentiation, the analysis of population structure suggests a complex and partially hierarchic pattern of genetic differentiation. The observed pattern suggests that initial colonization was followed by local differentiation and varying degrees of dispersal, most likely depending on local habitat conditions and prevailing current systems separating the Baltic Sea populations. Local subpopulations generally exhibited low levels of overall gene diversity. Association analysis suggests predominately asexual reproduction most likely accompanied by frequency shifts of clonal lineages during planktonic growth. Our results indicate that the general pattern of genetic differentiation and reduced genetic diversity of Baltic populations found in large organisms also applies to microscopic eukaryotic organisms. PMID:23300940

Late Quaternary stratigraphy of the La Janda Basin (SW Spain) - first results and palaeoenvironmental significance

NASA Astrophysics Data System (ADS)

Höbig, Nicole; Santisteban, Juan; Mediavilla, Rosa; May, Simon Matthias; Klasen, Nicole; Brückner, Helmut; van't Hoff, Jasmijn; Reicherter, Klaus

2017-04-01

The La Janda basin in southern Spain is a near-shore geo-bio-archive comprising a variable Quaternary depositional history, with shallow marine, lacustrine, palustrine, and terrestrial strata. In the 1930s the lake was drained and is serving now as a huge agricultural area. The 33 m-core recovered in fall 2016 along with several shallower drill cores up to c. 15 m, reveals insights into a unique mixed terrestrial palaeo-environmental archive in Andalucia influenced by the Atlantic Ocean and hence the North Atlantic Oscillation (NAO) within the Gulf of Cádiz. The basin's evolution was influenced both by the postglacial marine transgression and by an active tectonic fault controlling most of the accommodation space by causing subsidence. Our long core was accompanied by further corings along an E-W striking transect in order to reveal also the relation of the influence of tectonic activity with sedimentary sequences. Multi-Sensor Core Logging has been completed. Results of sedimentological, geochemical and micropalaeontological analyses will be presented in the frame of the climate variations during the Late Pleistocene and the Holocene, along with a preliminary age-depth model based on radiocarbon (AMS-14C) and optical stimulated luminescence (OSL) dating techniques. Our investigations ultimately aim at providing valuable information on major Late Pleistocene to Holocene climatic and palaeo-environmental fluctuations in the southernmost part of the Iberian Peninsula.

Patterns of post-glacial genetic differentiation in marginal populations of a marine microalga.

PubMed

Tahvanainen, Pia; Alpermann, Tilman J; Figueroa, Rosa Isabel; John, Uwe; Hakanen, Päivi; Nagai, Satoshi; Blomster, Jaanika; Kremp, Anke

2012-01-01

This study investigates the genetic structure of an eukaryotic microorganism, the toxic dinoflagellate Alexandrium ostenfeldii, from the Baltic Sea, a geologically young and ecologically marginal brackish water estuary which is predicted to support evolution of distinct, genetically impoverished lineages of marine macroorganisms. Analyses of the internal transcribed spacer (ITS) sequences and Amplified Fragment Length Polymorphism (AFLP) of 84 A. ostenfeldii isolates from five different Baltic locations and multiple external sites revealed that Baltic A. ostenfeldii is phylogenetically differentiated from other lineages of the species and micro-geographically fragmented within the Baltic Sea. Significant genetic differentiation (F(ST)) between northern and southern locations was correlated to geographical distance. However, instead of discrete genetic units or continuous genetic differentiation, the analysis of population structure suggests a complex and partially hierarchic pattern of genetic differentiation. The observed pattern suggests that initial colonization was followed by local differentiation and varying degrees of dispersal, most likely depending on local habitat conditions and prevailing current systems separating the Baltic Sea populations. Local subpopulations generally exhibited low levels of overall gene diversity. Association analysis suggests predominately asexual reproduction most likely accompanied by frequency shifts of clonal lineages during planktonic growth. Our results indicate that the general pattern of genetic differentiation and reduced genetic diversity of Baltic populations found in large organisms also applies to microscopic eukaryotic organisms.

Extraordinarily rapid speciation in a marine fish

PubMed Central

Momigliano, Paolo; Jokinen, Henri; Fraimout, Antoine; Florin, Ann-Britt; Norkko, Alf; Merilä, Juha

2017-01-01

Divergent selection may initiate ecological speciation extremely rapidly. How often and at what pace ecological speciation proceeds to yield strong reproductive isolation is more uncertain. Here, we document a case of extraordinarily rapid speciation associated with ecological selection in the postglacial Baltic Sea. European flounders (Platichthys flesus) in the Baltic exhibit two contrasting reproductive behaviors: pelagic and demersal spawning. Demersal spawning enables flounders to thrive in the low salinity of the Northern Baltic, where eggs cannot achieve neutral buoyancy. We show that demersal and pelagic flounders are a species pair arising from a recent event of speciation. Despite having a parapatric distribution with extensive overlap, the two species are reciprocally monophyletic and show strongly bimodal genotypic clustering and no evidence of contemporary migration, suggesting strong reproductive isolation. Divergence across the genome is weak but shows strong signatures of selection, a pattern suggestive of a recent ecological speciation event. We propose that spawning behavior in Baltic flounders is the trait under ecologically based selection causing reproductive isolation, directly implicating a process of ecological speciation. We evaluated different possible evolutionary scenarios under the approximate Bayesian computation framework and estimate that the speciation process started in allopatry ∼2,400 generations ago, following the colonization of the Baltic by the demersal lineage. This is faster than most known cases of ecological speciation and represents the most rapid event of speciation ever reported for any marine vertebrate. PMID:28533412

No evidence of extraterrestrial noble metal and helium anomalies at Marinoan glacial termination

NASA Astrophysics Data System (ADS)

Peucker-Ehrenbrink, Bernhard; Waters, Christine A.; Kurz, Mark D.; Hoffman, Paul F.

2016-03-01

High concentrations of extraterrestrial iridium have been reported in terminal Sturtian and Marinoan glacial marine sediments and are used to argue for long (likely 3-12 Myr) durations of these Cryogenian glaciations. Reanalysis of the Marinoan sedimentary rocks used in the original study, supplemented by sedimentary rocks from additional terminal Marinoan sections, however, does not confirm the initial report. New platinum group element concentrations, and 187Os/188Os and 3He/4He signatures are consistent with crustal origin and minimal extraterrestrial contributions. The discrepancy is likely caused by different sample masses used in the two studies, with this study being based on much larger samples that better capture the stochastic distribution of extraterrestrial particles in marine sediments. Strong enrichment of redox-sensitive elements, particularly rhenium, up-section in the basal postglacial cap carbonates, may indicate a return to more fully oxygenated seawater in the aftermath of the Marinoan snowball earth. Sections dominated by hydrogenous osmium indicate increasing submarine hydrothermal sources and/or continental inputs that are increasingly dominated by young mantle-derived rocks after deglaciation. Sedimentation rate estimates for the basal cap carbonates yield surprisingly slow rates of a few centimeters per thousand years. This study highlights the importance of using sedimentary rock samples that represent sufficiently large area-time products to properly sample extraterrestrial particles representatively, and demonstrates the value of using multiple tracers of extraterrestrial matter.

Evidence for Isostatic Emergence and Holocene Environmental Change Recorded in Chironomid Assemblages and Sediment Composition of Coastal Lake T1 in SW Greenland

NASA Astrophysics Data System (ADS)

Berman, K.; Axford, Y.; Lasher, G. E.

2017-12-01

Multi-proxy analysis of a coastal lake in southwest Greenland near Nuuk provides evidence for regional environmental changes, including the timing of isostatic rebound and the temperature history of the area. T1 (informal name) is a small lake 50 km south of Nuuk, at 17.5 m elevation and currently isolated from glacial meltwater drainage. The lake's sediment record begins approximately 9500 cal years BP, when the site was submerged beneath sea level due to glacial isostatic depression following the Last Glacial Maximum. The record captures the transition of the environment from a submerged, glacially-influenced marine site to a non-glacially fed (and initially meromictic) freshwater lake 8600 cal years BP. Magnetic susceptibility, a proxy for sediment minerogenic content, decreased rapidly from 9500 to 8600 years BP, before abruptly stabilizing and remaining relatively low and steady for the rest of the record. The transition to a lacustrine environment was characterized by a rapid and relatively simultaneous increase in primary productivity (inferred from biogenic silica concentrations) and shift towards terrestrial versus marine sources of organic matter (inferred from carbon:nitrogen ratios and nitrogen isotopes) between 8700 and 8400 years BP. Together, these proxies and the presence of marine shells below the transition provide robust evidence for the transition from a marine environment to a freshwater lake in response to regional postglacial isostatic rebound. Within the Holocene, measures of bulk sediment composition (e.g., biogenic silica, loss-on-ignition and magnetic susceptibility) are relatively stable. Chironomid (Insecta: Diptera: Chironomidae) assemblages, which in some environments are quantitative proxies for summer temperature changes, show species-level shifts within the Holocene that will be interpreted in this presentation alongside indicators of landscape change including carbon:nitrogen ratios, bulk sediment spectral reflectance and bulk sediment elemental composition from scanning XRF.

Marine infectious disease ecology

USGS Publications Warehouse

Lafferty, Kevin D.

2017-01-01

To put marine disease impacts in context requires a broad perspective on the roles infectious agents have in the ocean. Parasites infect most marine vertebrate and invertebrate species, and parasites and predators can have comparable biomass density, suggesting they play comparable parts as consumers in marine food webs. Although some parasites might increase with disturbance, most probably decline as food webs unravel. There are several ways to adapt epidemiological theory to the marine environment. In particular, because the ocean represents a three-dimensional moving habitat for hosts and parasites, models should open up the spatial scales at which infective stages and host larvae travel. In addition to open recruitment and dimensionality, marine parasites are subject to fishing, filter feeders, dosedependent infection, environmental forcing, and death-based transmission. Adding such considerations to marine disease models will make it easier to predict which infectious diseases will increase or decrease in a changing ocean.

Predicted bounds on peak global mean sea level during marine isotope stages 5a and 5c

NASA Astrophysics Data System (ADS)

Creveling, Jessica R.; Mitrovica, Jerry X.; Clark, Peter U.; Waelbroeck, Claire; Pico, Tamara

2017-05-01

Estimates of marine isotope stage (MIS) 5c and 5a global mean sea level (GMSL) based on marine terraces and coastal indicators range from 15-37 m and 9-30 m below present, respectively. Tectonic displacement and glacial isostatic adjustment (GIA) complicate efforts to refine this range. We revisit this issue using numerical predictions of post-glacial sea-level change and updated estimates of site-specific tectonic signals based upon these predictions. Laurentide and Cordilleran peripheral bulge dynamics and variations in the gravitational effect of these ice masses dominate the GIA signal along the east and west coasts of North America. Published compilations suggest that MIS 5 sea-level indicators extending from Virginia to the Caribbean lie on the outer flank of the peripheral bulge, while those along a transect from Oregon to Baja California sit on the inner flank of the bulge. Our GIA modeling reconciles these data by adopting a significantly weaker (i.e., lower viscosity) upper mantle in analyzing data on the Pacific coast relative to the Atlantic, an inference supported by seismic tomography. We present a sensitivity analysis that compares the observed elevation of globally distributed high stand markers to a suite of GIA simulations that vary the Earth model and GMSL from the Last Interglaciation (MIS 5e, ∼130-115 ka) to 70 ka. We conclude that GMSL peaked at -8.5 ± 4.6 m (1σ) during MIS 5a and -9.4 ± 5.3 m during MIS 5c. A more restrictive analysis yields slightly wider bounds corresponding to -10.5 ± 5.5 m and -11.1 ± 6.6 m, respectively.

Quaternary seismic stratigraphy and paleoenvironments on the continental shelf of the East China Sea

NASA Astrophysics Data System (ADS)

Liu, Zhen-Xia; Berne, Serge; Saito, Yoshiki; Lericolais, G.; Marsset, T.

2000-08-01

Paleoenvironments and stratigraphy have been interpreted from 4380 km of seismic profiling collected during a geological and geophysical cruise on the continental shelf of the East China Sea (ECS) undertaken in 1996. The geophysical data are correlated with a borehole situated on the outer shelf obtained by Shanghai Marine Geology Bureau, indicating that six seismic units have been preserved since oxygen-isotope stage 6, including four regressive-transgressive cycles. Seismic units U2, U3+U4+U5, U6, and U7 are interpreted to correspond respectively to oxygen-isotope stages 1, 3, 5, and 6, implying that sediment partitioning and sequence architecture in the ECS have been controlled by glacio-eustasy and global climate changes. Alternating continental and marine strata corresponding to glaciation and interglaciation are well preserved on the outer shelf of the ECS. Most of the cold environment strata, which formed on the outer shelf during oxygen-isotope stages 2 and 4, are too thin to be recognized on SIG 600J because of resolution, but corresponding erosion surfaces exist. Seismic unit U7 is widespread over the shelf, extending to the continental edge and showing little variation in thickness, as the regression was pronounced and lasted a long time. Thus, U7 can be used as a marker layer for correlation of Quaternary strata on the shelf of the ECS. Post-glacial transgression is obvious in the ECS. Marine strata with varied thickness were developed in the shallow sea of the inner shelf, thinning toward the outer shelf. The continental shelf of the ECS has been influenced by Pacific tide-wave systems for a long time, forming tidal sand-ridge sequences, developed during transgressions, corresponding to oxygen-isotope stages 7 (or 9), 5, 3 and 1.

The geomorphic signature of present ice-sheet flow in the radar-sounded subglacial record: Pine Island Glacier, West Antarctica

NASA Astrophysics Data System (ADS)

Bingham, R. G.; Davies, D.; King, E. C.; Vaughan, D. G.; Cornford, S. L.; Brisbourne, A.; Smith, A.; De Rydt, J.; Graham, A. G. C.; Spagnolo, M.

2016-12-01

Deglaciated landscapes and landforms are much used in the quest to reconstruct past ice-sheet behaviour, on the principle that aspects of landform shapes, sizes and relative associations "fossilise" palaeo-ice-sheet processes. Such techniques have been widely used around the margin of the marine West Antarctic Ice Sheet, taking advantage of bathymetric surveying techniques which have exposed a rich suite of landform assemblages across West Antarctica's continental shelf. Though these geomorphological interpretations are solidly grounded in glacial geological theory, there has, until now, been little ability to compare these deglaciated, and potentially postglacially-modified, landforms offshore with landforms currently situated (and potentially still evolving) beneath the contemporary ice sheet. This paper presents a widespread view of glacial landforms presently situated beneath 1-2 km of ice in multi-square-km "windows to the bed" distributed throughout the catchment of Pine Island Glacier, West Antarctica. Imaged over three field seasons between 2007 and 2013 by dedicated radar surveys designed specifically to capture landforms analogous to those surveyed offshore by bathymetric surveying, the results provide significant insights for the interpretation of palaeo-ice-stream landforms, and their use in modelling ice-ocean interactions around the fringes of marine ice sheets. We show that landform sizes, shapes and associations vary significantly around Pine Island Glacier's catchment. The key controls appear to be substrate composition, pre-existing tectonic structure, and longstanding spatial stability of the ice-stream's flow distribution. The findings offer crucial information for modelling ice coupling to the bed, which should feed through to wider efforts to reconstruct the past behaviour of this significant marine ice sheet using its palaeoglacial landforms.

Identifying Meteorological Controls on Open and Closed Mesoscale Cellular Convection as Associated with Marine Cold Air Outbreaks

NASA Astrophysics Data System (ADS)

McCoy, Isabel; Wood, Robert; Fletcher, Jennifer

Marine low clouds are key influencers of the climate and contribute significantly to uncertainty in model climate sensitivity due to their small scale and complex processes. Many low clouds occur in large-scale cellular patterns, known as open and closed mesoscale cellular convection (MCC), which have significantly different radiative and microphysical properties. Investigating MCC development and meteorological controls will improve our understanding of their impacts on the climate. We conducted an examination of time-varying meteorological conditions associated with satellite-determined open and closed MCC. The spatial and temporal patterns of MCC clouds were compared with key meteorological control variables calculated from ERA-Interim Reanalysis to highlight dependencies and major differences. This illustrated the influence of environmental stability and surface forcing as well as the role of marine cold air outbreaks (MCAO, the movement of cold air from polar-regions across warmer waters) in MCC cloud formation. Such outbreaks are important to open MCC development and may also influence the transition from open to closed MCC. Our results may lead to improvements in the parameterization of cloudiness and advance the simulation of marine low clouds. National Science Foundation Graduate Research Fellowship Grant (DGE-1256082).

Seasonal variation of marine organic aerosols in the North Pacific Ocean

NASA Astrophysics Data System (ADS)

Fu, P.; Kawamura, K.

2017-12-01

Atmospheric aerosols were collected in the marine boundary layer during five marine cruises in the northern Pacific Ocean from October 1996 to July 1997. Organic molecular compositions of the marine aerosols were measured using gas chromatography/mass spectrometry (GC/MS). Higher concentrations of levoglucosan and its isomers, the biomass-burning tracers, were observed in the coastal regions than those in the central north Pacific. Seasonal trends of biomass burning tracers were found to be higher in fall-winter-spring than in summer, suggesting an enhanced influence of continental aerosols to the marine atmosphere during cold seasons when the westerlies prevail. However, the atmospheric levels of secondary organic aerosol (SOA) tracers from the photooxidation of isoprene and monoterpenes were higher in warm seasons than cold seasons, which are in accordance with the enhanced emissions of biogenic volatile organic compounds (BVOCs) in summer. Stable C isotope ratios of total carbon (δ13CTC) in the marine aerosols ranged from -28.5‰ to -23.6‰ (mean -26.4‰), suggesting an important input of terrestrial/continental aerosol particles. Stable N isotope ratios (2.6‰ to 12.9‰, mean 7.1‰) were found to be higher in the coastal regions than those in the open oceans, suggesting an enhanced emission of marine aerosols in the open oceans. The fluorescence properties of the water-soluble organic carbon (WSOC) in the marine aerosols conform the importance of marine emitted organics in the open ocean, especially during the high biological activity periods.

Marine Corps Recruits: A Historical Look at Accessions and Bootcamp Performance

DTIC Science & Technology

2010-09-01

without the promise of an occupational field . Their code is PN, and these are called open contracts. In this slide, we graph the percentage of open ...means that occupational specialties such as infantry, armor, field artillery, and short-range air defense artillery are closed to women...enlistment contracts began for small numbers of Marines. While the 3 -, 4-, and 6-year initial enlistment contracts were open to the same group of MOSs

Methane fluxes and their controlling processes in the Baltic Sea

NASA Astrophysics Data System (ADS)

Rehder, G. J.; Fossing, H.; Lapham, L.; Endler, R.; Spiess, V.; Bruchert, V.; Nguyen, T.; Gülzow, W.; Schneider von Deimling, J.; Conley, D. J.; Jorgensen, B.

2010-12-01

The Baltic Sea is an ideal natural laboratory to study the methane cycle in the framework of diagenetic processes. With its brackish character and a gradient from nearly marine to almost limnic conditions, a strong permanent haline stratification leading to large vertical redox gradients in the water column, and a sedimentation history which resulted in the deposition of organic-rich young post-glacial sediments over older glacial and post-glacial strata with very low organic content, the Baltic allows to study the role of a variety of key parameters for early diagenetic processes including the methane cycle. Within the BONUS + Project “Baltic Gas”, a 3.5 week scientific expedition of RV Maria S. Merian in August 2010 was dedicated to study the methane cycle in the various basins of the Baltic Sea, with strong emphasis on the metabolic reactions of early diagenesis and the occurrence of shallow gas deposits. Various subbottom profiling systems were used to map the thickness and structure of organic-rich deposits and build the base for a detailed coring program for biogeochemical analysis, including methane, sulfur compounds, iron, and other compounds. Methane gradients in connection with the information of the areal extend of organic-rich deposits are used to estimate the diffusive flux from the sediments into the water column and the rate of methane oxidation, with changing importance of sulfate as oxidant along the salinity gradient. On selected key stations, rate measurements of methanogenic and methanotrophic reactions were executed. The methane distribution in the water column was comprehensively assessed, revealing amongst other findings a drastic increase in bottom water methane concentration between the post bloom summer situation and the situation in the winter of 2009, in connection to the occurrence of a benthic nepheloid layer. Air-sea flux measurements were executed along the ship’s track comprising all major basins of the Baltic. The talk gives an interdisciplinary overview of the first results of this research campaign.

Pollen-based evidence of extreme drought during the last Glacial (32.6-9.0 ka) in coastal southern California

NASA Astrophysics Data System (ADS)

Heusser, Linda E.; Kirby, Matthew E.; Nichols, Jonathan E.

2015-10-01

High resolution pollen analyses of sediment core LEDC10-1 from Lake Elsinore yield the first well-dated, terrestrial record of sub-centennial-scale ecologic change in coastal southern California between ˜32 and 9 ka. In the Lake Elsinore watershed, the initial, mesic montane conifer forests dominated by Pinus, and Cupressaceae with trace amounts of Abies and Picea were replaced by a sequence of multiple, extended severe mega-droughts between ˜27.5 and ˜25.5 ka, in which halophytic and xerophytic herbs and shrubs occupied an ephemeral lake. This prolonged and extended dry interval, which corresponds with warm waters offshore, imply strengthening of the North Pacific High and persistent below-average winter precipitation. The subsequent, contrasting monotonic occurrence of montane conifers reflects little variation in cold, mesic climate until ˜15 ka. Postglacial development of Quercus woodland and chaparral mark the return to more xeric, warmer conditions at this time. A brief reversal at ˜13.1-˜12.1 ka, as reflected by an expansion of Pinus, is correlative with the Younger Dryas and interrupts development of warm, postglacial climate. Subsequent gradual expansion of xeric vegetation post - Younger Dryas denotes the establishment of a winter hydroclimate regime in coastal southern California that is more similar to modern conditions. Pollen-based reconstructions of temperature and precipitation at Lake Elsinore are generally correlative with pollen-based paleoclimatic reconstructions and foraminifera-based sea surface temperatures from Santa Barbara Basin in marine core ODP 893. The conspicuous absence of the ˜27.5-˜25.5 ka glacial "mega-drought" in the Santa Barbara Basin pollen record highlights the sensitivity of Lake Elsinore to hydroclimate change, and thus, the importance of this new record that indicates that mega-drought can occur during the full glacial when climatic boundary conditions and forcings differed substantially from the present.

German-Russian project PLOT: new postglacial-glacial-preglacial pollen records from the Lakes Ladoga and Bol'shoe Shuch'e

NASA Astrophysics Data System (ADS)

Andreev, A.; Savelieva, L.; Shumilovskikh, L.; Gromig, R.; Wennrich, V.; Fedorov, G.; Wagner, B.; Melles, M.

2017-12-01

The German-Russian project PLOT (PaleolimnoLOgical Transect) investigates the Late Quaternary environmental history along the Northern Eurasia transect. Within the scope of a pilot phase of the project we have investigated Lake Ladoga, the largest lake in Europe. Although the postglacial history of the lake was studied over the last decades, the preglacial history remained unknown. It is assumed that during the Last Interglacial Lake Ladoga was part of a precursor of the Baltic Sea, which had a connection via Ladoga and Onega Lakes to the White Sea. Sediment coring at two sites in western Ladoga Lake in September 2013 has revealed sediment succession subdivided into 5 main lithological units. The sediments studied in a 22.7 m lake core were also palynologically investigated. Pollen assemblages indicate that the lowermost sediments with pollen of Betula, Alnus, Pinus, Carpinus, Quercus, Corylus, Ulmus, Tilia, remains of fresh-water Pediastrum and Botryococcus colonies as well as cysts of marine dinoflagellates and brackish water acritarchs) were accumulated during an interglacial with climate more favorable than in the Holocene. The OSL-dated samples show the late Eemian and post Eemian ages. Lake Bol'shoe Shuch'e (Polar Urals) was cored in April 2016. The thickness of the lacustrine sediments was 54 m. According to the previous studies, most of the study area has remained ice-free over the last 50-60 ka. However, the configuration and timing of the preceding glaciations has remained unclear, because of lack continuous, long-term paleoenvironmental records in the area. Preliminary studies show that the uppermost 9 m of the sediments were accumulated during the Holocene, between 11 and 9 m - in Younger Dryas, between 11 and 9 m - in Allerod, between 11 and 25 m - in MIS 2, between 25 and 54 m - in the MIS 3. We expect that the core will provide the most continuous sediment records from the whole region which can be used to reconstruct the environmental changes.

Subarctic Lake Sediment Microbial Community Contributions to Methane Emission Patterns

NASA Astrophysics Data System (ADS)

Emerson, J. B.; Varner, R. K.; Parks, D.; Wik, M.; Neumann, R.; Johnson, J. E.; Singleton, C. M.; Woodcroft, B. J.; Tollerson, R., II; Owusu-Dommey, A.; Binder, M.; Freitas, N. L.; Crill, P. M.; Saleska, S. R.; Tyson, G. W.; Rich, V. I.

2017-12-01

Northern post-glacial lakes have recently been identified as a significant and increasing source of carbon to the atmosphere, largely through ebullition (bubbling) of microbially produced methane from the sediments. Ebullitive methane flux has been shown to correlate significantly with sediment surface temperatures, suggesting that solar radiation is the primary driver of methane emissions from these lakes. However, the slope of this relationship (i.e., the extent to which increasing temperature increases ebullitive methane emissions) differs spatially, both within and among lakes. As microbes are responsible for both methane generation and removal in lakes, we hypothesized that microbial communities—previously uncharacterized in post-glacial lake sediments—could be contributing to spatiotemporal differences in methane emission responses to temperature. We compared methane emission data with sediment microbial (metagenomic and amplicon), isotopic, and geochemical characterizations across two post-glacial lakes in Northern Sweden. With increasing temperatures, the increase in methane emissions was greater in lake middles (deeper water) than lake edges (shallower water), consistent with higher abundances of methanogens in sediments from lake middles than edges, along with significant differences in microbial community composition between these regions. Using sparse partial least squares statistical modeling, microbial abundances (including the abundances of methane-cycling microorganisms and of reconstructed population genomes, e.g., from Planctomycetes, Thermoplasmatales, and Candidate Phylum Aminicenantes) were better predictors of porewater methane concentrations than abiotic variables. These results suggest that, although temperature controls methane emissions, microbial community composition and function may drive the rate and magnitude of this temperature response in subarctic post-glacial lakes.

Mapping Post-Glacial expansions: The Peopling of Southwest Asia

PubMed Central

Platt, Daniel E.; Haber, Marc; Dagher-Kharrat, Magda Bou; Douaihy, Bouchra; Khazen, Georges; Ashrafian Bonab, Maziar; Salloum, Angélique; Mouzaya, Francis; Luiselli, Donata; Tyler-Smith, Chris; Renfrew, Colin; Matisoo-Smith, Elizabeth; Zalloua, Pierre A.

2017-01-01

Archaeological, palaeontological and geological evidence shows that post-glacial warming released human populations from their various climate-bound refugia. Yet specific connections between these refugia and the timing and routes of post-glacial migrations that ultimately established modern patterns of genetic variation remain elusive. Here, we use Y-chromosome markers combined with autosomal data to reconstruct population expansions from regional refugia in Southwest Asia. Populations from three regions in particular possess distinctive autosomal genetic signatures indicative of likely refugia: one, in the north, centered around the eastern coast of the Black Sea, the second, with a more Levantine focus, and the third in the southern Arabian Peninsula. Modern populations from these three regions carry the widest diversity and may indeed represent the most likely descendants of the populations responsible for the Neolithic cultures of Southwest Asia. We reveal the distinct and datable expansion routes of populations from these three refugia throughout Southwest Asia and into Europe and North Africa and discuss the possible correlations of these migrations to various cultural and climatic events evident in the archaeological record of the past 15,000 years. PMID:28059138

Postglacial Rebound from VLBI Geodesy: On Establishing Vertical Reference

NASA Technical Reports Server (NTRS)

Argus, Donald F.

1996-01-01

Difficulty in establishing a reference frame fixed to the earth's interior complicates the measurement of the vertical (radial) motions of the surface. I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan] and predictions from postglacial rebound predictions [Peltier]. The optimal translation of the geocenter is 1.7mm/year toward 36degN, 111degE when determined from the motions of 10 VLBI sites. This translation gives a better fit of observations to predictions than does the VLBI reference frame used by Ma and Ryan, but the improvement is statistically insignificant. The root mean square of differences decreases 20% to 0.73 mm/yr and the correlation coefficient increases from 0.76 to 0.87. Postglacial rebound is evident in the uplift of points in Sweden and Ontario that were beneath the ancient ice sheets of Fennoscandia and Canada, and in the subsidence of points in the northeastern U.S., Germany, and Alaska that were around the periphery of the ancient ice sheets.

Fire and vegetation shifts in the Americas at the vanguard of Paleoindian migration

NASA Astrophysics Data System (ADS)

Pinter, Nicholas; Fiedel, Stuart; Keeley, Jon E.

2011-02-01

Across North and South America, the final millennia of the Pleistocene saw dramatic changes in climate, vegetation, fauna, fire regime, and other local and regional paleo-environmental characteristics. Rapid climate shifts following the Last Glacial Maximum (LGM) exerted a first-order influence, but abrupt post-glacial shifts in vegetation composition, vegetation structure, and fire regime also coincided with human arrival and transformative faunal extinctions in the Americas. We propose a model of post-glacial vegetation change in response to climatic drivers, punctuated by local fire regime shifts in response to megaherbivore-driven fuel changes and anthropogenic ignitions. The abrupt appearance of humans, disappearance of megaherbivores, and resulting changes in New World fire systems were transformative events that should not be dismissed in favor of climate-only interpretations of post-glacial paleo-environmental shifts in the Americas. Fire is a mechanism by which small human populations can have broad impacts, and growing evidence suggests that early anthropogenic influences on regional, even global, paleo-environments should be tested alongside other potential causal mechanisms.

Extra-Mediterranean refugia: The rule and not the exception?

PubMed Central

2012-01-01

Some decades ago, biogeographers distinguished three major faunal types of high importance for Europe: (i) Mediterranean elements with exclusive glacial survival in the Mediterranean refugia, (ii) Siberian elements with glacial refugia in the eastern Palearctic and only postglacial expansion to Europe and (iii) arctic and/or alpine elements with large zonal distributions in the periglacial areas and postglacial retreat to the North and/or into the high mountain systems. Genetic analyses have unravelled numerous additional refugia both of continental and Mediterranean species, thus strongly modifying the biogeographical view of Europe. This modified notion is particularly true for the so-called Siberian species, which in many cases have not immigrated into Europe during the postglacial period, but most likely have survived the last, or even several glacial phases, in extra-Mediterranean refugia in some climatically favourable but geographically limited areas of southern Central and Eastern Europe. Recently, genetic analyses revealed that typical Mediterranean species have also survived the Last Glacial Maximum in cryptic northern refugia (e.g. in the Carpathians or even north of the Alps) in addition to their Mediterranean refuge areas. PMID:22953783

Open Science: a first step towards Science Communication

NASA Astrophysics Data System (ADS)

Grigorov, Ivo; Tuddenham, Peter

2015-04-01

As Earth Science communicators gear up to adopt the new tools and captivating approaches to engage citizen scientists, budding entrepreneurs, policy makers and the public in general, researchers have the responsibility, and opportunity, to fully adopt Open Science principles and capitalize on its full societal impact and engagement. Open Science is about removing all barriers to basic research, whatever its formats, so that it can be freely used, re-used and re-hashed, thus fueling discourse and accelerating generation of innovative ideas. The concept is central to EU's Responsible Research and Innovation philosophy, and removing barriers to basic research measurably contributes to engaging citizen scientists into the research process, it sets the scene for co-creation of solutions to societal challenges, and raises the general science literacy level of the public. Despite this potential, only 50% of today's basic research is freely available. Open Science can be the first passive step of communicating marine research outside academia. Full and unrestricted access to our knowledge including data, software code and scientific publications is not just an ethical obligation, but also gives solid credibility to a more sophisticated communication strategy on engaging society. The presentation will demonstrate how Open Science perfectly compliments a coherent communication strategy for placing Marine Research in societal context, and how it underpin an effective integration of Ocean & Earth Literacy principles in standard educational, as well mobilizing citizen marine scientists, thus making marine science Open Science.

Basin fill evolution and paleotectonic patterns along the Samfrau geosyncline: the Sauce Grande basin-Ventana foldbelt (Argentina) and Karoo basin-Cape foldbelt (South Africa) revisited

NASA Astrophysics Data System (ADS)

López-Gamundí, O. R.; Rossello, E. A.

As integral parts of du Toit's (1927) ``Samfrau Geosyncline'', the Sauce Grande basin-Ventana foldbelt (Argentina) and Karoo basin-Cape foldbelt (South Africa) share similar paleoclimatic, paleogeographic, and paleotectonic aspects related to the Late Paleozoic tectono-magmatic activity along the Panthalassan continental margin of Gondwanaland. Late Carboniferou-earliest Permian glacial deposits were deposited in the Sauce Grande (Sauce Grande Formation) and Karoo (Dwyka Formation) basins and Falkland-Malvinas Islands (Lafonia Formation) during an initial (sag) phase of extension. The pre-breakup position of the Falkland (Malvinas) Islands on the easternmost part of the Karoo basin (immediately east of the coast of South Africa) is supported by recent paleomagnetic data, lithofacies associations, paleoice flow directions and age similarities between the Dwyka and the Lafonia glacial sequences. The desintegration of the Gondwanan Ice Sheet (GIS) triggered widespread transgressions, reflected in the stratigraphic record by the presence of inter-basinally correlatable, open marine, fine-grained deposits (Piedra Azul Formation in the Sauce Grande basin, Prince Albert Formation in the Karoo basin and Port Sussex Formation in the Falkland Islands) capping glacial marine sediments. These early postglacial transgressive deposits, characterised by fossils of the Eurydesma fauna and Glossopteris flora, represent the maximum flooding of the basins. Cratonward foreland subsidence was triggered by the San Rafael orogeny (ca. 270 Ma) in Argentina and propogated along the Gondwanan margin. This subsidence phase generated sufficient space to accommodate thick synorogenic sequences derived from the orogenic flanks of the Sauce Grande and Karoo basins. Compositionally, the initial extensional phase of these basins was characterized by quartz-rich, craton-derived detritus and was followed by a compressional (foreland) phase characterized by a paleocurrent reversal and dominance of arc/foldbelt-derived material. In the Sauce Grande basin, tuffs are interbedded in the upper half of the synorogenic, foldbelt-derived Tunas Formation (Early-early Late? Permian). Likewise, the first widespread appearance of tuffs in the Karoo basin is in the Whitehill Formation, of late Early Permian (260 Ma) age. Silicic volcanism along the Andes and Patagonia (Choiyoi magmatic province) peaked between the late Early Permian and Late Permian. A link between these volcanics and the consanguineous airborne tuffs present in the Sauce Grande and Karoo basins is suggested on the basis of their similar compositions and ages.

Evolution of the polar oceans: the late Quaternary palaeoceanography of the Northwest Passage

NASA Astrophysics Data System (ADS)

Pienkowski, Anna; Furze, Mark; England, John; MacLean, Brian; Bennett, Robbie; Blasco, Steve; McNeely, Morgan

2014-05-01

The marine channels of the Canadian Arctic Archipelago, collectively known as the "Northwest Passage" (= NWP), cover some 1.1 million km2 on the North American continental shelf and constitute one of two primary pathways for water and heat exchange between the Arctic and Atlantic oceans. Modern circulation is characterized by a net southeastward flow from the Arctic Ocean through Parry Channel (the main W-E axis of the NWP) towards Baffin Bay, with Arctic Ocean Surface Water primarily occupying the NWP channels. Data from recent and ongoing marine work* highlight a dynamic oceanographic environment since the last glaciation. A suite of five sediment records (piston and trigger weight cores) taken in a transect through Parry Channel provide important information on the long-term (deglacial to postglacial) environmental and oceanographic evolution of the region. The cores were studied by a multiproxy approach encompassing sedimentology, micropalaeontology, biogeochemistry, constrained by a chronological framework of 58 AMS radiocarbon dates. Our data suggest grounded glacial ice in the channels of the Canadian Arctic Archipelago, rapid deglaciation, and a characteristic progression from ice-proximal to ice-distal conditions. Age model extrapolations place deglaciation at ~13.0-10.3 cal ka BP (location dependent). Noticeable biological activity is marked by the appearance of planktonic foraminifera (Neogloboquadrina pachyderma) at ~11.0 cal ka BP - an important signal given the absence of these organisms in the modern NWP. This likely marks the penetration of Atlantic-derived water (Arctic Intermediate Water) into the central NWP following deglaciation, likely facilitated by higher deglacial sea-levels permitting increased flow across inter-channel sills. Though the route of this Atlantic-derived water is currently being resolved, it may have penetrated from Baffin Bay in the East into the NWP, contrary to the modern circulation. Subsequent (~9.7-7.0 cal ka BP) ameliorated conditions (open-water season greater than present) marked by substantial diversification and abundance across all microfossil groups may correspond to a previously postulated regional "Holocene Thermal Optimum". After ~7.0 cal ka BP increased sea-ice and modern microfossil assemblages imply conditions similar to modern, likely due to the exclusion of Arctic Intermediate Water due to glacio-isostatic shallowing combined with climate cooling. * [Marie Curie FP7-PEOPLE-2011-CIG 304178- QUEEN (Quaternary Environmental Evolution of the Northwest-Passage)

Preliminary results from fault-slip analysis of the Pärvie neotectonic postglacial fault zone, northern Sweden

NASA Astrophysics Data System (ADS)

Backstrom, Ann; Viola, Giulio; Rantakokko, Nina; Jonsson, Erik; Ask, Maria

2013-04-01

Our study aims at constraining the paleostress field evolution of neotectonic postglacial faulting in northern Sweden. Postglacial faulting is a special type of intraplate faulting triggered by the retreat of continental glaciers and by the induced changes of the local stress field. We investigated the longest known post-glacial fault (PGF) in Scandinavia, the Pärvie PGF. It is 155 km long and consists of a series of 3-10 m high fault scarps developed in several rock types such as mafic and felsic meta-volcanic rocks, and in the north, Archean granites and gneisses. Most of the scarps trend north-northeast and dip steeply to the west. A smaller sibling fault to the east (the Lansjärv PGF) displaces postglacial sediments. It is interpreted as resulting from a great earthquake (M≤8.2) at the end or just after the last glaciation (~10 ky B.P.). Microseismic activity is still present along the Pärvie fault zone. Unfortunately, the stress history of the Pärvie PGF before the last glaciation is poorly known. To reconstruct its stress history, we have performed fault-slip analysis. Fault slip data have been collected from two profiles across the Pärvie PGF in the Corruvagge valley and in Kamasjaure in the north, and Stora Sjöfallet in the southern part of the fault zone. Cross-cutting relationships, fracture mineralization and structural features of the brittle overprint of the rocks have been used to suggest a conceptual model of the brittle history of the fault. Ca. 40 kinematically constrained fault planes were used in the inversion study in addition to ca. 1060 fractures. Preliminary results indicate that the oldest generation of fractures are coated by pink plagioclase and clinoamphibole. The key mineral epidote is prominent along cataclastic structures. Rarly multiple kinematic indicators are identified along the same fracture, indicating polyphase reactivation. Epidote coating is found along fractures from all the computed stress-fields, indicating that epidote coating is diagnostic of the early faulting phases as well as of the youngest. Four distinct stress fields were identified, whereof the youngest is assigned to the Pärvie PG faulting event. This study confirms that postglacial faulting have reactivated an old fault system, which had accommodated at least three earlier episodes of brittle deformation. Comparison with paleostress studies of regional significance elsewhere in Fennoscandia makes it possible to tentatively assign these older events to a deformation phase shortly after the Svecokarelian orogeny, around 1,7 Ga, and one stress-field that can be either the stress field during the Sveconorwegian or Caledonian orogeny. An extensional phase has also been identified but not further constrained, yet.

An introduction to the design of marine propulsors

NASA Technical Reports Server (NTRS)

Henderson, R. E.

1974-01-01

A summary of methods for marine propulsion design is presented. A list of reports dealing with the design of open propellers, ducted propellers or pumpjets, and waterjets is included. The major problems involved in marine propulsion design are discussed.

78 FR 18965 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-28

... Drilling Program in the Chukchi Sea, Alaska AGENCY: National Marine Fisheries Service (NMFS), National... numbers of marine mammals, by harassment, incidental to conducting offshore exploration drilling on Outer... offshore exploration drilling on OCS leases in the Chukchi Sea, Alaska, during the 2014 open-water season...

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED...

Mapping and vessel-based capabilities

USGS Publications Warehouse

Raabe, Ellen A.; Robbins, Lisa L.

2007-01-01

U.S. Geological Survey (USGS) scientists from the Florida Integrated Science Center (FISC) conduct scientific investigations of submerged coastal and marine resources using new and existing technologies. Each contributing technique, method, or product adds to our understanding of coastal and marine resources and provides information for resource-management decisionmaking. In support of this mission, the USGS St. Petersburg office maintains a fleet of research vessels used for inland, coastal, and open-water marine surveys and investigations. Each vessel has advantages and limitations related to water depth, carrying capacity, speed, operation in open water, and other functions. These research platforms are staffed by experienced technical and scientific professionals with expertise in marine navigation, geology, geophysics, engineering, biology, and oceanography.

Deciphering the Preparatory and Triggering Factors Responsible for Post-Glacial Slope Failures: Insights from Landslide Age and Morphology in Yellowstone National Park

NASA Astrophysics Data System (ADS)

Nicholas, G.; Dixon, J. L.; Pierce, K. L.

2017-12-01

Landslides are ubiquitous to post-glacial landscapes worldwide. Withdrawal of glacier ice exposes oversteepened landscapes that may be unstable, and consequently susceptible to landsliding. Several disparate mechanisms can act as triggers: glacial debuttressing can directly destabilize slopes; however, changes in climate resulting in greater effective moisture and subsequent degradation of permafrost may also play a role. Here, we quantify relative age, spatial relationships, and topographic metrics in a set of post-glacial landslides in northwest Yellowstone National Park. Preliminary analysis of high-resolution topography indicates increasing surface roughness of non-active landslides southward, consistent with younging ages along the retreat path of the Yellowstone Ice Cap. These roughness values in ancient slides are roughly half those of the active Slide Lake Landslide within the same study region. However, the changes in roughness within the non-active landslides disappear when we remove biases such as gullying, fluvial erosional contacts, and areas believed to have been remobilized. These removed areas appear largely linked to a Holocene incision pulse up the Gardiner River, which interacts with the toes of landslides in the southern region. Stream power analysis indicates that incision is focused at a knickpoint locally coincident with the toe of the modern and active Slide Lake Landslide. Our results indicate caution should be used when using surface roughness for landslide ages without accounting for both intrinsic and extrinsic changes in erosion of the landslide system, and suggest tight links between modern stream erosion and landslide reactivation. Insights from this dynamic landscape in Yellowstone National Park are actively being used by park officials to mitigate risk, and broadly show that quantifying the temporal and spatial patterns of landslides can provide diagnostic understanding of the long-term controls on post-glacial slope failure.

78 FR 33700 - Special Local Regulations for Marine Events, Pleasantville Aquatics 15th Annual 5K Open Water...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-05

...-AA08 Special Local Regulations for Marine Events, Pleasantville Aquatics 15th Annual 5K Open Water Swim... from operating while a swim event is taking place. This special local regulation is necessary to... Docket Management Facility in Room W12-140 on the ground floor of the Department of Transportation West...

Pleistocene climatic oscillations in Neotropical open areas: Refuge isolation in the rodent Oxymycterus nasutus endemic to grasslands

PubMed Central

Peçanha, Willian T.; Althoff, Sergio L.; Galiano, Daniel; Quintela, Fernando M.; Maestri, Renan; Freitas, Thales R. O.

2017-01-01

Pleistocene climatic oscillations favoured the expansion of grassland ecosystems and open vegetation landscapes throughout the Neotropics, and influenced the evolutionary history of species adapted to such environments. In this study, we sampled populations of the rodent Oxymycterus nasutus endemic to open areas in the Pampas and Atlantic Forest biomes to assess the tempo and mode of population divergence using an integrative approach, including coalescence theory, ecological niche models, and morphometry. Our results indicated that these O. nasutus populations exhibited high levels of genetic structure. Six major mtDNA clades were found, structuring these biomes into distinct groups. Estimates of their divergence times was indicated to be 0.571 myr. The high degree of genetic structure is reflected in the analyses of geometric morphometric; skull differences between lineages in the two ecoregions were detected. During the last glacial maximum, there was a strong increase in suitable abiotic conditions for O. nasutus. Distinct molecular markers revealed a population expansion over time, with a possible demographic retraction during the post-glacial period. Considering that all clades coalesce with the last interglacial maximum, our results indicated that reduction in suitable conditions during this period may have resulted in a possible vicariance associated with refuge isolation. PMID:29176839

75 FR 49759 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

...In accordance with the Marine Mammal Protection Act (MMPA) regulations, notification is hereby given that NMFS has issued an Incidental Harassment Authorization (IHA) to Statoil USA E&P Inc. (Statoil) to take, by harassment, small numbers of 12 species of marine mammals incidental to a marine seismic survey program in the Chukchi Sea, Alaska, during the 2010 Arctic open water season.

Territorial user rights for fisheries as ancillary instruments for marine coastal conservation in Chile.

PubMed

Gelcich, Stefan; Fernández, Miriam; Godoy, Natalio; Canepa, Antonio; Prado, Luis; Castilla, Juan Carlos

2012-12-01

Territorial user rights for fisheries have been advocated as a way to achieve sustainable resource management. However, few researchers have empirically assessed their potential as ancillary marine conservation instruments by comparing them to no-take marine protected areas. In kelp (Lessonia trabeculata) forests of central Chile, we compared species richness, density, and biomass of macroinvertebrates and reef fishes among territorial-user-right areas with low-level and high-level enforcement, no-take marine protected areas, and open-access areas in 42 100-m subtidal transects. We also assessed structural complexity of the kelp forest and substratum composition. Multivariate randomized permutation tests indicated macroinvertebrate and reef fish communities associated with the different access regimes differed significantly. Substratum composition and structural complexity of kelp forest did not differ among access regimes. Univariate analyses showed species richness, biomass, and density of macroinvertebrates and reef fishes were greater in highly enforced territorial-user-right areas and no-take marine protected areas than in open-access areas. Densities of macroinvertebrates and reef fishes of economic importance were not significantly different between highly enforced territorial-user-right and no-take marine protected areas. Densities of economically important macroinvertebrates in areas with low-level enforcement were significantly lower than those in areas with high-level enforcement and no-take marine protected areas but were significantly higher than in areas with open access. Territorial-user-right areas could be important ancillary conservation instruments if they are well enforced. ©2012 Society for Conservation Biology.

Postglacial eruptive history of the Askja region, North Iceland

NASA Astrophysics Data System (ADS)

Hartley, Margaret E.; Thordarson, Thorvaldur; de Joux, Alexandra

2016-04-01

Temporal variations in magma discharge rates on Iceland's neovolcanic rift zones have been associated with deglaciation. We have used tephrochronological and stratigraphic dating of 175 separate eruptive units to estimate volumetric output and reconstruct eruption rates in the Askja region over the postglacial period. We have identified 14 tephra layers that can be used as time marker horizons in the near vicinity of Askja, including the Vatnaöldur (871 ± 2 AD) tephra which has not previously been reported in surface cover profiles in this region. Our improved tephrochronological resolution indicates that, over the past c. 1,500 years, Askja has been significantly more active than has previously been recognised. A minimum of 39 km3 of basaltic magma has been erupted at Askja since the area became ice-free at around 10.3 ka. The absence of the 7.2 ka Hekla 5 tephra from the Askja region suggests that all postglacial lavas now exposed at the surface are younger than 7.2 ka. Time-averaged magma discharge rates at Askja were highest between 7.2 and 4.3 ka. However, the available tephrochronological resolution is not sufficient to resolve any peak in volcanic activity following deglaciation.

Postglacial vegetation history of Orcas Island, northwestern Washington

NASA Astrophysics Data System (ADS)

Leopold, Estella B.; Dunwiddie, Peter W.; Whitlock, Cathy; Nickmann, Rudy; Watts, William A.

2016-05-01

The revegetation of islands following retreat of Pleistocene glaciers is of great biogeographical interest. The San Juan Islands, Washington, feature regionally distinctive xerophytic plant communities, yet their vegetation history, as it relates to past climate and sea level, is poorly known. We describe a 13,700-year-old pollen record from Killebrew Lake Fen and compare the vegetation reconstruction with others from the region. The data suggest that the narrow channels surrounding Orcas Island were not a barrier to early postglacial immigration of plants. Between 13,700 and 12,000 cal yr BP, Pinus, Tsuga, Picea, Alnus viridis, and possibly Juniperus maritima were present in a mosaic that supported Bison antiquus and Megalonyx. The rise of Alnus rubra-type pollen and Pteridium spores at ca. 12,000 cal yr BP suggests a warming trend and probably more fires. Temperate conifer taxa, including Cupressaceae, Pseudotsuga, Tsuga heterophylla, and Abies, increased after 11,000 cal yr BP and especially in the last 7000 cal yr BP. After 6000 cal yr BP, Pseudotsuga and Cupressaceae dominated the vegetation. The last 1500 yr were the wettest period of the record. Due to its rain shadow location, Orcas Island experienced drier conditions than on the mainland during most of the postglacial period.

Post-glacial Paleo-oceanographic and Paleo-climatic Conditions and Linkages Along the West Coast of Canada

NASA Astrophysics Data System (ADS)

Dallimore, A.; Enkin, R. J.; McKechnie, I.

2006-12-01

Along the west coast of Canada, our continuing studies of annually laminated marine sediments in anoxic fjords illustrate the changing environment as glaciers retreated from this area about 12 ka y BP. New data from mid-coastal British Columbia expands our knowledge of the interplay between climate and ocean dynamics in the northeastern Pacific Ocean, and defines the evolution of modern climate conditions as ice receded from the coast, followed by the establishment of modern oceanographic and climatic conditions about 6,000 ky BP. The Late Pleistocene and Holocene record also marks dramatic changes in sea level, climate, coastal oceanographic dynamics and glacial sedimentary source and transport, with implications for the possibility of early human migration routes and glacial refugia. Changes in pre-historical aboriginal settlement sites and food sources also give indications of a dynamic Holocene land and seascape as modern conditions became established. Excellent chronological control is provided by complementary yet independent dating methods including radiocarbon dates on both plants and shells, identification of the Mazama Ash, varve counting and paleomagnetic/paleosecular variation correlations.

King penguin demography since the last glaciation inferred from genome-wide data

PubMed Central

Trucchi, Emiliano; Gratton, Paolo; Whittington, Jason D.; Cristofari, Robin; Le Maho, Yvon; Stenseth, Nils Chr; Le Bohec, Céline

2014-01-01

How natural climate cycles, such as past glacial/interglacial patterns, have shaped species distributions at the high-latitude regions of the Southern Hemisphere is still largely unclear. Here, we show how the post-glacial warming following the Last Glacial Maximum (ca 18 000 years ago), allowed the (re)colonization of the fragmented sub-Antarctic habitat by an upper-level marine predator, the king penguin Aptenodytes patagonicus. Using restriction site-associated DNA sequencing and standard mitochondrial data, we tested the behaviour of subsets of anonymous nuclear loci in inferring past demography through coalescent-based and allele frequency spectrum analyses. Our results show that the king penguin population breeding on Crozet archipelago steeply increased in size, closely following the Holocene warming recorded in the Epica Dome C ice core. The following population growth can be explained by a threshold model in which the ecological requirements of this species (year-round ice-free habitat for breeding and access to a major source of food such as the Antarctic Polar Front) were met on Crozet soon after the Pleistocene/Holocene climatic transition. PMID:24920481

Lagrangian analysis of multi-satellite data in support of open ocean Marine Protected Area design

NASA Astrophysics Data System (ADS)

Della Penna, Alice; Koubbi, Philippe; Cotté, Cedric; Bon, Cécile; Bost, Charles-André; d'Ovidio, Francesco

2017-06-01

Compared to ecosystem conservation in territorial seas, protecting the open ocean has peculiar geopolitical, economic and scientific challenges. One of the major obstacle is defining the boundary of an open ocean Marine Protected Area (MPA). In contrast to coastal ecosystems, which are mostly constrained by topographic structures fixed in time, the life of marine organisms in the open ocean is entrained by fluid dynamical structures like eddies and fronts, whose lifetime occurs on ecologically-relevant timescales. The position of these highly dynamical structures can vary interannually by hundreds of km, and so too will regions identified as ecologically relevant such as the foraging areas of marine predators. Thus, the expected foraging locations suggested from tracking data cannot be directly extrapolated beyond the year in which the data were collected. Here we explore the potential of Lagrangian methods applied to multisatellite data as a support tool for a MPA proposal by focusing on the Crozet archipelago oceanic area (Indian Sector of the Southern Ocean). By combining remote sensing with biologging information from a key marine top predator (Eudyptes chrysolophus, or Macaroni penguin) of the Southern Ocean foodweb, we identify a highly dynamic branch of the Subantarctic front as a foraging hotspot. By tracking this feature in historical satellite data (1993-2012) we are able to extrapolate the position of this foraging ground beyond the years in which tracking data are available and study its spatial variability.

46 CFR 61.05-15 - Boiler mountings and attachments.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC...) Each valve shall be opened and examined by the marine inspector at the interval specified in Table 61... the boiler and be examined by the marine inspector at the interval specified by Table 61.05-10 when...

46 CFR 61.05-15 - Boiler mountings and attachments.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC...) Each valve shall be opened and examined by the marine inspector at the interval specified in Table 61... the boiler and be examined by the marine inspector at the interval specified by Table 61.05-10 when...

46 CFR 61.05-15 - Boiler mountings and attachments.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC...) Each valve shall be opened and examined by the marine inspector at the interval specified in Table 61... the boiler and be examined by the marine inspector at the interval specified by Table 61.05-10 when...

46 CFR 61.05-15 - Boiler mountings and attachments.

Code of Federal Regulations, 2011 CFR

2011-10-01

...-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC...) Each valve shall be opened and examined by the marine inspector at the interval specified in Table 61... the boiler and be examined by the marine inspector at the interval specified by Table 61.05-10 when...

46 CFR 61.05-15 - Boiler mountings and attachments.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC...) Each valve shall be opened and examined by the marine inspector at the interval specified in Table 61... the boiler and be examined by the marine inspector at the interval specified by Table 61.05-10 when...

Marine geology of the Near Islands Shelf, Alaska

USGS Publications Warehouse

Scruton, Philip Challacombe

1953-01-01

During the summer of 1950 on the insular shelf surrounding the Near Islands, Alaska, 193 oceanographic stations were occupied from aboard the U. S. Geological Survey vessel EIDER. Bottom character and temperature observations were made at these stations. The composition and size distribution characteristics of the bottom samples have been determined. Components of terrigenous origin are angular to subangular sand and silt and angular to well rounded granules, pebbles, and cobbles, all composed of little-altered fragments of the fine grained insular rocks. Components of marine origin are the skeletons of Foraminifera, diatoms, and sponges and the broken shells of a few species of mollusks and of one echinoid species. A chart, based also on the study of approximately 600 USC&GS bottom notations, was prepared to show the distribution of these components of the sediments. Bed rock is exposed on most of the shelf; where sediment occurs terrigenous components are generally most important near shore, whereas marine components are more important seaward of the islands. Studies of the Foraminifera fauna and the diatom flora (identified by K. E. Lohman) and the few mollusks of quantitative importance show these organisms to be forms characteristic of cold or deep water or occurring in a wide range of temperature conditions. The Foraminifera exhibit depth zonation which seems to be controlled in part by temperature and in part by depth or some other variable which is a function of depth. Sphericity and roundness studies made on pebbles from the shelf, the beaches, and the fluvio-glacial deposits together with shelf topographic features and Foraminifera from sediment deposited before ice wastage was complete suggest the shelf was not subjected to prolonged surf action during the post-glacial rise of sea level. To aid in interpreting the sediments and their distribution several subaerial and marine environmental factors were investigated. Those factors found to be of most importance in determining sediment character and distribution are recent geologic history, nature of terrigenous source material, temperature, topography, rainfall, size of source area, history of the water mass, waves, and currents. The data derived from this study show the importance of climate as an important variable in determining sediment character and distribution in the Near Islands.

Features of shoreline displacement in the Holocene of Franz josef Land Archipelago

NASA Astrophysics Data System (ADS)

Barliaev, A.; Anisimov, M.

2014-12-01

Changes in the global sea level after the LGM caused the significant alteration in relation of land and sea in Arctic. The rise of the sea level in Arctic was accompanied with present tectonic processes. Marine terraces are formed with the combination of eustatic sea level fluctuations and glacioisostatic uplift of the territory with the significant role of complicated tectonic block movements. There are nearly about 150 radiocarbon ages data for Franz-Josef Land archipelago now. The represented conclusions are a generalization of the published data and results of our field researches with series of new radiocarbon dates. We managed to collect valuable factual material during the Russian Arctic National Park expedition in 2012. The distinctions of post-glacial rise of different islands and peculiarities of Holocene deglaciation were identified with the help of marine terraces analysis. The altitude of the terraces with the same age on different islands exceeds 15 meters in some cases. However, analysis of the data suggests that the continuous series of raised beaches from 35 m a.s.l. formed during the last 10000 years. It is impossible to build up an univocal model of emergence isobases with the existing data. Alexandra Land Island was the special object of this investigation. The large beach ridge from Lunar Ice Cap to Kropotkina Ice Cap divides the island on two parts. The northern one is covered with marine sediments, whereas the southern - with glaciofluvial sediments with negligible areas of marine sediments. The difference between the terraces' ages of Alexandra Land on the Dezhneva Bay shore and the northern shore of island suggests that: 1) In the early Holocene the rate of the transgression exceeded the tectonic uplift of the territory; 2) Formation of the large central beach ridge occurred near 6700 years ago, the maximum marine limit in the Alexandra Land Island; 3) The rate of the tectonic rise of the territory exceeded the eustatic sea level rise in the period after 6700 years ago; 4) The formation of the large central beach ridge took place when the Ice Capes occupied less space than now. We express our gratitude to the administration of Russian Arctic National Park for providing access to FJL archipelago and organization of the expedition.

Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA

USGS Publications Warehouse

Buatois, L.A.; Mangano, M.G.; Alissa, A.; Carr, T.R.

2002-01-01

Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing a variety of depositional environments such as fluvial channel, interfluve paleosol, bay head delta, estuary bay, restricted tidal flat, intertidal channel, and estuary mouth. Deposition in a brackish-water estuarine valley is supported by the presence of a low diversity, opportunistic, impoverished marine ichnofaunal assemblage dominated by infaunal structures, representing an example of a mixed, depauperate Cruziana and Skolithos ichnofacies. Overall distribution of ichnofossils along the estuarine valley was mainly controlled by the salinity gradient, with other parameters, such as oxygenation, substrate and energy, acting at a more local scale. The lower Morrow estuarine system displays the classical tripartite division of wave-dominated estuaries (i.e. seaward-marine sand plug, fine-grained central bay, and sandy landward zone), but tidal action is also recorded. The estuarine valley displays a northwest-southeast trend, draining to the open sea in the southeast. Recognition of valley-fill sandstones in the lower Morrow has implications for reservoir characterization. While the open marine model predicts a "layer-cake" style of facies distribution as a consequence of strandline shoreline progradation, identification of valley-fill sequences points to more compartmentalized reservoirs, due to the heterogeneity created by valley incision and subsequent infill. The open-marine facies assemblage comprises upper, middle, and lower shoreface; offshore transition; offshore; and shelf deposits. In contrast to the estuarine assemblage, open marine ichnofaunas are characterized by a high diversity of biogenic structures representing the activity of a benthic fauna developed under normal salinity conditions. Trace fossil and facies analyses allow environmental subdivision of the shoreface-offshore successions and suggest deposition in a weakly storm-affected nearshore area. An onshore-offshore replacement of the Skolithos ichnofacies by the Cruziana ichnofacies is clearly displayed. The lower Morrow fluvio-estuarine valley was incised during a drop of sea level coincident with the Mississippian-Pennsylvanian transition, but was mostly filled during a subsequent transgression. The transgressive nature of the estuarine infill is further indicated by the upward replacement of depauperate brackish-water trace fossil assemblages by the open-marine Cruziana ichnofacies. Additional stratal surfaces of allostratigraphic significance identified within the estuary include the bayline surface, the tidal ravinement surface, the wave ravinement surface, and a basinwide flooding surface recording inundation of the valley interfluves. A younger sequence boundary within the lower Morrow is also recorded in the Gentzler field at the base of a forced regression shoreface, demarcated by the firmground Glossifungites ichnofacies, indicating a rapid basinward facies migration during a sea-level drop. Trace fossil models derived from the analysis of Mesozoic and Cenozoic reservoirs are generally applicable to the study of these late Paleozoic reservoirs. Pennsylvanian brackish-water facies differ ichnologically from their post-Paleozoic counterparts, however, in that they have: (1) lower trace fossil diversity, (2) lower degree of bioturbation, (3) scarcity of crustacean burrows, (4) absence of firmground suites, and (5) absence of ichnotaxa displaying specific architectures designed to protect the tracemaker from salinity fluctuations. Morrow open-marine ichnofaunas closely resemble their post-Paleozoic equivalents. ?? 2002 Elsevier Science B.V. All rights reserved.

Informatics and Decisions support in Galway Bay (SmartBay) using ERDDAP, OGC Technologies and Third Party Data Sources to Provide Services to the Marine Community.

NASA Astrophysics Data System (ADS)

Delaney, Conor; Gaughan, Paul; Smyth, Damian

2013-04-01

The global marine sector generates and consumes vast quantities of operational and forecast data on a daily basis. One of the key challenges facing the sector relates to the management and transformation of that data into knowledge. The Irish Marine Institute (MI) generates oceanographic and environmental data on a regular and frequent basis. This data comes from operational ocean models run on the MI's high performance computer (HPC) and various environmental observation sensors systems. Some of the data published by the Marine Institute is brokered by the Environmental Research Division's Data Access Program (ERDDAP) data broker, which is a broker technology that uses technology based on OPeNDAP and Open Geospatial Consortium (OGC) standards. The broker provides a consistent web service interface to the data services of the Marine Institute; these services include wave, tide and weather sensors and numerical model output. An ERDDAP server publishes data in a number of standard and developer friendly ways, including some OGC formats. The data on the MI ERDDAP (http://erddap.marine.ie) server is published as OpenData. The marine work package of the FP7 funded ENVIROFI project (http://www.envirofi.eu/) has used the ERDDAP data broker as a core resource in the development of its Marine Asset management decision Support Tool (MAST) portal and phone App. Communication between MAST and ERDDAP is via a Uniform Resource Identifier (Linked Data). A key objective of the MAST prototype is to demonstrate the potential of next-generation dynamic web-based products and services and how they can be harnessed to facilitate growth of both the marine and IT sectors. The use case driving the project is the management of ocean energy assets in the marine environment. In particular the provision of information that aid in the decision making process surrounding maintenance at sea. This question is common to any offshore industry and solution proposed here is applicable to other users of Galway Bay, Ireland. The architecture of the MAST is based on the concepts of Representational State Transfer (REST), Resource Orientated Architecture (ROA), Service Orientated Architecture (SOA), OpenData and MASHUPS. In this paper we demonstrate the architecture of the MAST system and discuss the potential of ERDDAP technology to serve complex data in formats that are accessible to the general developer community. We also discuss of the potential of next generation web technologies and OpenData to encourage the use of valuable marine data resources.

Quaternary Geologic Map of Connecticut and Long Island Sound Basin

USGS Publications Warehouse

Stone, Janet Radway; Schafer, John P.; London, Elizabeth Haley; DiGiacomo-Cohen, Mary L.; Lewis, Ralph S.; Thompson, Woodrow B.

2005-01-01

The Quaternary geologic map (sheet 1) and explanatory figures and cross sections (sheet 2) portray the geologic features formed in Connecticut during the Quaternary Period, which includes the Pleistocene (glacial) and Holocene (postglacial) Epochs. The Quaternary Period has been a time of development of many details of the landscape and of all the surficial deposits. At least twice in the late Pleistocene, continental ice sheets swept across Connecticut. Their effects are of pervasive importance to the present occupants of the land. The Quaternary geologic map illustrates the geologic history and the distribution of depositional environments during the emplacement of glacial and postglacial surficial deposits and the landforms resulting from those events.

The postglacial recolonization of Northern Europe by Rana arvalis as revealed by microsatellite and mitochondrial DNA analyses.

PubMed

Knopp, T; Merilä, J

2009-02-01

The postglacial history of the moor frog (Rana arvalis) in Northern Europe was investigated with the aid of eight variable microsatellite loci and a 661 bp sequence of the mitochondrial cytochrome b gene. A division between eastern and western mitochondrial lineages was discovered, supporting two recolonization routes to Fennoscandia since the last glacial maximum. This result was corroborated by the microsatellite data, which revealed a contact zone between the two lineages in Northern Sweden. These findings add to the increasing evidence that an intraspecific genetic biodiversity founded on the existence of eastern and western clades is a common element in Fennoscandian fauna and flora.

Recent Earth oblateness variations: unraveling climate and postglacial rebound effects.

PubMed

Dickey, Jean O; Marcus, Steven L; de Viron, Olivier; Fukumori, Ichiro

2002-12-06

Earth's dynamic oblateness (J2) has been decreasing due to postglacial rebound (PGR). However, J2 began to increase in 1997, indicating a pronounced global-scale mass redistribution within Earth's system. We have determined that the observed increases in J2 are caused primarily by a recent surge in subpolar glacial melting and by mass shifts in the Southern, Pacific, and Indian oceans. When these effects are removed, the residual trend in J2 (-2.9 x 10(-11) year-1) becomes consistent with previous estimates of PGR from satellite and eclipse data. The climatic significance of these rapid shifts in glacial and oceanic mass, however, remains to be investigated.

78 FR 24731 - Taking Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to an...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-26

... Drilling Program in the Chukchi Sea, Alaska AGENCY: National Marine Fisheries Service (NMFS), National... conducting offshore exploration drilling on Outer Continental Shelf (OCS) leases in the Chukchi Sea, Alaska... incidental to COP's offshore exploration drilling in the Chukchi Sea during the 2014 open- [[Page 24732...

77 FR 47424 - Merchant Marine Personnel Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

... various issues related to the training and fitness of merchant marine personnel. This meeting will be open..., documentation, and fitness standards. The Committee will advise, consult with, and make [[Page 47425...

Origin and diet of the prehistoric hunter-gatherers on the mediterranean island of Favignana (Ègadi Islands, Sicily).

PubMed

Mannino, Marcello A; Catalano, Giulio; Talamo, Sahra; Mannino, Giovanni; Di Salvo, Rosaria; Schimmenti, Vittoria; Lalueza-Fox, Carles; Messina, Andrea; Petruso, Daria; Caramelli, David; Richards, Michael P; Sineo, Luca

2012-01-01

Hunter-gatherers living in Europe during the transition from the late Pleistocene to the Holocene intensified food acquisition by broadening the range of resources exploited to include marine taxa. However, little is known on the nature of this dietary change in the Mediterranean Basin. A key area to investigate this issue is the archipelago of the Ègadi Islands, most of which were connected to Sicily until the early Holocene. The site of Grotta d'Oriente, on the present-day island of Favignana, was occupied by hunter-gatherers when Postglacial environmental changes were taking place (14,000-7,500 cal BP). Here we present the results of AMS radiocarbon dating, palaeogenetic and isotopic analyses undertaken on skeletal remains of the humans buried at Grotta d'Oriente. Analyses of the mitochondrial hypervariable first region of individual Oriente B, which belongs to the HV-1 haplogroup, suggest for the first time on genetic grounds that humans living in Sicily during the early Holocene could have originated from groups that migrated from the Italian Peninsula around the Last Glacial Maximum. Carbon and nitrogen isotope analyses show that the Upper Palaeolithic and Mesolithic hunter-gatherers of Favignana consumed almost exclusively protein from terrestrial game and that there was only a slight increase in marine food consumption from the late Pleistocene to the early Holocene. This dietary change was similar in scale to that at sites on mainland Sicily and in the rest of the Mediterranean, suggesting that the hunter-gatherers of Grotta d'Oriente did not modify their subsistence strategies specifically to adapt to the progressive isolation of Favignana. The limited development of technologies for intensively exploiting marine resources was probably a consequence both of Mediterranean oligotrophy and of the small effective population size of these increasingly isolated human groups, which made innovation less likely and prevented transmission of fitness-enhancing adaptations.

Origin and Diet of the Prehistoric Hunter-Gatherers on the Mediterranean Island of Favignana (Ègadi Islands, Sicily)

PubMed Central

Mannino, Marcello A.; Catalano, Giulio; Talamo, Sahra; Mannino, Giovanni; Di Salvo, Rosaria; Schimmenti, Vittoria; Lalueza-Fox, Carles; Messina, Andrea; Petruso, Daria; Caramelli, David; Richards, Michael P.; Sineo, Luca

2012-01-01

Hunter-gatherers living in Europe during the transition from the late Pleistocene to the Holocene intensified food acquisition by broadening the range of resources exploited to include marine taxa. However, little is known on the nature of this dietary change in the Mediterranean Basin. A key area to investigate this issue is the archipelago of the Ègadi Islands, most of which were connected to Sicily until the early Holocene. The site of Grotta d’Oriente, on the present-day island of Favignana, was occupied by hunter-gatherers when Postglacial environmental changes were taking place (14,000-7,500 cal BP). Here we present the results of AMS radiocarbon dating, palaeogenetic and isotopic analyses undertaken on skeletal remains of the humans buried at Grotta d’Oriente. Analyses of the mitochondrial hypervariable first region of individual Oriente B, which belongs to the HV-1 haplogroup, suggest for the first time on genetic grounds that humans living in Sicily during the early Holocene could have originated from groups that migrated from the Italian Peninsula around the Last Glacial Maximum. Carbon and nitrogen isotope analyses show that the Upper Palaeolithic and Mesolithic hunter-gatherers of Favignana consumed almost exclusively protein from terrestrial game and that there was only a slight increase in marine food consumption from the late Pleistocene to the early Holocene. This dietary change was similar in scale to that at sites on mainland Sicily and in the rest of the Mediterranean, suggesting that the hunter-gatherers of Grotta d’Oriente did not modify their subsistence strategies specifically to adapt to the progressive isolation of Favignana. The limited development of technologies for intensively exploiting marine resources was probably a consequence both of Mediterranean oligotrophy and of the small effective population size of these increasingly isolated human groups, which made innovation less likely and prevented transmission of fitness-enhancing adaptations. PMID:23209602

Impact of seasonal and postglacial surface displacement on global reference frames

NASA Astrophysics Data System (ADS)

Krásná, Hana; Böhm, Johannes; King, Matt; Memin, Anthony; Shabala, Stanislav; Watson, Christopher

2014-05-01

The calculation of actual station positions requires several corrections which are partly recommended by the International Earth Rotation and Reference Systems Service (IERS) Conventions (e.g., solid Earth tides and ocean tidal loading) as well as other corrections, e.g. accounting for hydrology and atmospheric loading. To investigate the pattern of omitted non-linear seasonal motion we estimated empirical harmonic models for selected stations within a global solution of suitable Very Long Baseline Interferometry (VLBI) sessions as well as mean annual models by stacking yearly time series of station positions. To validate these models we compare them to displacement series obtained from the Gravity Recovery and Climate Experiment (GRACE) data and to hydrology corrections determined from global models. Furthermore, we assess the impact of the seasonal station motions on the celestial reference frame as well as on Earth orientation parameters derived from real and also artificial VLBI observations. In the second part of the presentation we apply vertical rates of the ICE-5G_VM2_2012 vertical land movement grid on vertical station velocities. We assess the impact of postglacial uplift on the variability in the scale given different sampling of the postglacial signal in time and hence on the uncertainty in the scale rate of the estimated terrestrial reference frame.

Long-distance dispersal or postglacial contraction? Insights into disjunction between Himalaya-Hengduan Mountains and Taiwan in a cold-adapted herbaceous genus, Triplostegia.

PubMed

Niu, Yan-Ting; Ye, Jian-Fei; Zhang, Jin-Long; Wan, Ji-Zhong; Yang, Tuo; Wei, Xiao-Xin; Lu, Li-Min; Li, Jian-Hua; Chen, Zhi-Duan

2018-01-01

Current disjunct patterns can result from long-distance dispersal or postglacial contraction. We herein investigate the evolutionary history of Triplostegia to elucidate the disjunction between the Himalaya-Hengduan Mountain region (HHM) and Taiwan (TW). Genetic structure of Triplostegia was investigated for 48 populations using sequences from five chloroplast loci and the ribosomal nuclear internal transcribed spacer. Divergence time estimation, ancestral area reconstruction, and species distribution modeling (SDM) were employed to examine the biogeographic history of Triplostegia . Substantial genetic differentiation among populations from southwestern China (SW), Central China (CC), and TW was detected. Triplostegia was inferred to have originated in SW, and diversification began during the late Miocene; CC was colonized in the mid-Pliocene, and TW was finally colonized in the early Pleistocene. SDM suggested an expansion of climatically suitable areas during the Last Glacial Maximum and range contraction during the Last interglacial in Triplostegia . Disjunction between HHM and TW in Triplostegia is most likely the consequence of topographic isolation and postglacial contraction. The potential climatic suitability areas for Triplostegia by 2070s (2061-2080) are predicted to slightly shrink and move northward. With continued global warming and human-induced deforestation, extinction risk may increase for the cold-adapted species, and appropriate strategies should be employed for ecosystem conservation.

Nuclear microsatellites reveal contrasting patterns of genetic structure between western and southeastern European populations of the common ash (Fraxinus excelsior L.).

PubMed

Heuertz, Myriam; Hausman, Jean-François; Hardy, Olivier J; Vendramin, Giovanni G; Frascaria-Lacoste, Nathalie; Vekemans, Xavier

2004-05-01

To determine extant patterns of population genetic structure in common ash and gain insight into postglacial recolonization processes, we applied multilocus-based Bayesian approaches to data from 36 European populations genotyped at five nuclear microsatellite loci. We identified two contrasting patterns in terms of population genetic structure: (1) a large area from the British Isles to Lithuania throughout central Europe constituted effectively a single deme, whereas (2) strong genetic differentiation occurred over short distances in Sweden and southeastern Europe. Concomitant geographical variation was observed in estimates of allelic richness and genetic diversity, which were lowest in populations from southeastern Europe, that is, in regions close to putative ice age refuges, but high in western and central Europe, that is, in more recently recolonized areas. We suggest that in southeastern Europe, restricted postglacial gene flow caused by a rapid expansion of refuge populations in a mountainous topography is responsible for the observed strong genetic structure. In contrast, admixture of previously differentiated gene pools and high gene flow at the onset of postglacial recolonization of western and central Europe would have homogenized the genetic structure and raised the levels of genetic diversity above values in the refuges.

Composition, spatial distribution and sources of macro-marine litter on the Gulf of Alicante seafloor (Spanish Mediterranean).

PubMed

García-Rivera, Santiago; Lizaso, Jose Luis Sánchez; Millán, Jose María Bellido

2017-08-15

The composition, spatial distribution and source of marine litter in the Spanish Southeast Mediterranean were assessed. The data proceed from a marine litter retention programme implemented by commercial trawlers and were analysed by GIS. By weight, 75.9% was plastic, metal and glass. Glass and plastics were mainly found close to the coast. A high concentration of metal was observed in some isolated zones of both open and coastal waters. Fishing activity was the source of 29.16% of the macro-marine litter, almost 68.1% of the plastics, and 25.1% of the metal. The source of the other 60.84% could not be directly identified, revealing the high degree of uncertainty regarding its specific origin. Indirectly however, a qualitative analysis of marine traffic shows that the likely sources were merchant ships mainly in open waters and recreational and fishing vessels in coastal waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Marine mammal distribution in the open ocean: a comparison of ocean color data products and levant time scales

NASA Astrophysics Data System (ADS)

Ohern, J.

2016-02-01

Marine mammals are generally located in areas of enhanced surface primary productivity, though they may forage much deeper within the water column and higher on the food chain. Numerous studies over the past several decades have utilized ocean color data from remote sensing instruments (CZCS, MODIS, and others) to asses both the quantity and time scales over which surface primary productivity relates to marine mammal distribution. In areas of sustained upwelling, primary productivity may essentially grow in the secondary levels of productivity (the zooplankton and nektonic species on which marine mammals forage). However, in many open ocean habitats a simple trophic cascade does not explain relatively short time lags between enhanced surface productivity and marine mammal presence. Other dynamic features that entrain prey or attract marine mammals may be responsible for the correlations between marine mammals and ocean color. In order to investigate these features, two MODIS (moderate imaging spectroradiometer) data products, the concentration as well as the standard deviation of surface chlorophyll were used in conjunction with marine mammal sightings collected within Ecuadorian waters. Time lags between enhanced surface chlorophyll and marine mammal presence were on the order of 2-4 weeks, however correlations were much stronger when the standard deviation of spatially binned images was used, rather than the chlorophyll concentrations. Time lags also varied between Balaenopterid and Odontocete cetaceans. Overall, the standard deviation of surface chlorophyll proved a useful tool for assessing potential relationships between marine mammal sightings and surface chlorophyll.

Integrating paleoecology and genetics of bird populations in two sky island archipelagos.

PubMed

McCormack, John E; Bowen, Bonnie S; Smith, Thomas B

2008-06-27

Genetic tests of paleoecological hypotheses have been rare, partly because recent genetic divergence is difficult to detect and time. According to fossil plant data, continuous woodland in the southwestern USA and northern Mexico became fragmented during the last 10,000 years, as warming caused cool-adapted species to retreat to high elevations. Most genetic studies of resulting 'sky islands' have either failed to detect recent divergence or have found discordant evidence for ancient divergence. We test this paleoecological hypothesis for the region with intraspecific mitochondrial DNA and microsatellite data from sky-island populations of a sedentary bird, the Mexican jay (Aphelocoma ultramarina). We predicted that populations on different sky islands would share common, ancestral alleles that existed during the last glaciation, but that populations on each sky island, owing to their isolation, would contain unique variants of postglacial origin. We also predicted that divergence times estimated from corrected genetic distance and a coalescence model would post-date the last glacial maximum. Our results provide multiple independent lines of support for postglacial divergence, with the predicted pattern of shared and unique mitochondrial DNA haplotypes appearing in two independent sky-island archipelagos, and most estimates of divergence time based on corrected genetic distance post-dating the last glacial maximum. Likewise, an isolation model based on multilocus gene coalescence indicated postglacial divergence of five pairs of sky islands. In contrast to their similar recent histories, the two archipelagos had dissimilar historical patterns in that sky islands in Arizona showed evidence for older divergence, suggesting different responses to the last glaciation. This study is one of the first to provide explicit support from genetic data for a postglacial divergence scenario predicted by one of the best paleoecological records in the world. Our results demonstrate that sky islands act as generators of genetic diversity at both recent and historical timescales and underscore the importance of thorough sampling and the use of loci with fast mutation rates to studies that test hypotheses concerning recent genetic divergence.

Post-glacial coast development and human settling of the North European Ice Marginal Landscape (IML)

NASA Astrophysics Data System (ADS)

Bregman, I. Kant Baltic Federal State University, Kaliningrad, Russia, E. P. H.; Netherlands, Utrecht University, the; Druzhinina, I. Kant Baltic Federal State University, Kaliningrad, Russia, O. A.

2012-04-01

In North Europe, in the Ice Marginal Landscapes (IML) from the Netherlands to Estonia, human settling is in the Late-Pleistocene - Holocene strongly influenced by post-glacial relative coast development(MESO, 2010; SINCOS, 2002-2009; Machu, 2006-2009, IGCP project 346, CoPaF, 2009-2012) and glacio-isostasy. Geological processes like updoming and tectonic block displacements not only influenced sedimentation of river systems in delta's (e.g. Cohen, 2003), but influenced coastal development and human settling too in the North Sea area (e.g. Peeters, 2009; Hijma e.a., 2011) the Wadden areas (e.g. de Langen, 2011) and lagoons (e.g. Druzhinina, 2010). An overview of shoreline development at the distal side of the Late Glacial forbulge related to glaciological and geophysical processes however does not exist and coastal development models are also not correlated with human settling. Our project( 2012 - 2018) has the aim to describe the influence of shifting coast on the way of settling and living of ancient man in the IML. The main questions to be answered are as follow: (i) Is coast development influenced by glaciations a result of interaction between endo- and exogenic (glaciological-, geological-, and geophysical) forces in general and at the local scale of morphological elements? (ii) Did ancient man adept to changes in natural circumstances and what did that mean for his social behavior and economy? (iii) Were forms of human society and economy in the IML primarily dependent on the natural environment with regard to geophysical and geological differences and related to post-glacial response of the earth crust? Detailed integrated studying of "key-areas", with attention to deep geology, will allow to get new insight of the impact of post-glacial shoreline changes and history of man on the coast in the IML with focus on his past (history of relations) and future (impact of climate change. The project is an international project, with participation of institutes all over the IML.

Postglacial seismic activity along the Isovaara-Riikonkumpu fault complex

NASA Astrophysics Data System (ADS)

Ojala, Antti E. K.; Mattila, Jussi; Ruskeeniemi, Timo; Palmu, Jukka-Pekka; Lindberg, Antero; Hänninen, Pekka; Sutinen, Raimo

2017-10-01

Analysis of airborne LiDAR-based digital elevation models (DEMs), trenching of Quaternary deposits, and diamond drilling through faulted bedrock was conducted to characterize the geological structure and full slip profiles of the Isovaara-Riikonkumpu postglacial fault (PGF) complex in northern Finland. The PGF systems are recognized from LiDAR DEMs as a complex of surface ruptures striking SW-NE, cutting through late-Weichselian till, and associated with several postglacial landslides within 10 km. Evidence from the terrain rupture characteristics, the deformed and folded structure of late-Weichselian till, and the 14C age of 11,300 cal BP from buried organic matter underneath the Sotka landslide indicates a postglacial origin of the Riikonkumpu fault (PGF). The fracture frequency and lithology of drill cores and fault geometry in the trench log indicate that the Riikonkumpu PGF dips to WNW with a dip angle of 40-45° at the Riikonkumpu site and close to 60° at the Riikonvaara site. A fault length of 19 km and the mean and maximum cumulative vertical displacement of 1.3 m and 4.1 m, respectively, of the Riikonkumpu PGF system indicate that the fault potentially hosted an earthquake with a moment magnitude MW ≈ 6.7-7.3 assuming that slip was accumulated in one seismic event. Our interpretation further suggests that the Riikonkumpu PGF system is linked to the Isovaara PGF system and that, together, they form a larger Isovaara-Riikonkumpu fault complex. Relationships between the 38-km-long rupture of the Isovaara-Riikonkumpu complex and the fault offset parameters, with cumulative displacement of 1.5 and 8.3 m, respectively, indicate that the earthquake(s) contributing to the PGF complex potentially had a moment magnitude of MW ≈ 6.9-7.5. In order to adequately sample the uncertainty space, the moment magnitude was also estimated for each major segment within the Isovaara-Riikonkumpu PGF complex. These estimates vary roughly between MW ≈ 5-8 for the individual segments.

The postglacial Stuoragurra Fault, North Norway - A textural and mineralogical study.

NASA Astrophysics Data System (ADS)

Roaldset, E.

2012-04-01

The postglacial Stuoragurra Fault, North Norway - A textural and mineralogical study Elen Roaldset(1), Mari Åm (2), and Oddleiv Olesen(3) 1) Natural History Museum, University of Oslo, P.O.Box 1172 Blindern, 0318 Oslo, Norway 2) Statoil R &D, P. O. Box 2470, 7005 Trondheim, Norway 3) Norwegian Geological Survey, P.O.Box 6315 Sluppen, 7491 Trondheim, Norway The Stuoragurra Fault is part of the Lapland province of postglacial faults and was identified in 1983 during a colloborative project between the Geological Surveys of Finland Norway and Sweden. The Stuoragurra Fault is an 80 km long fault zone which contains three main segments of eastward dipping faults (30-55 deg.) with up to 10 m of reverse displacement and a 7 m high escarpment. It cross-cuts glaciofluvial deposits and consequently being younger than 10.000 years. The postglacial fault segments follow to a large extent older fault zones represented by lithified breccias and diabases of Proterozoic age. In this paper we will present textural and mineralogical study of a 135 m continous core drilled across the fault zone. The investigation methods include quality assessments by rock quality designation methods (RQD and Q- methods), textural and petrological descriptions visually and by thin section microscopy, and mineralogical analysis by X-ray diffraction. Special attention is drawn to neoformed and/or degraded minerals like clay minerals and iron oxides/hydroxides. The quality assessments of the cored material reflect the degree of rock deformation and fragmentation and show the quality of the bedrock generally to be of very poor (about 60%) to poor quality" (25%) The main minerals in the fresh rock are quarts, feldspar, mica and iron oxides (magnetite and ilmenite). Throughout the cored borehole products of weathering have formed on fissures, fractures and in strongly deformed, gravelly, zones. The neoformed minerals include kaolinite, smectite, and vermiculite, as well as goethite. The mineralogical transformations will be discussed in relation to the rock texture,petrophysical properties and fault characteristics.

Genetic structure and demographic inference of the regular sea urchin Sterechinus neumayeri (Meissner, 1900) in the Southern Ocean: The role of the last glaciation.

PubMed

Díaz, Angie; Gérard, Karin; González-Wevar, Claudio; Maturana, Claudia; Féral, Jean-Pierre; David, Bruno; Saucède, Thomas; Poulin, Elie

2018-01-01

One of the most relevant characteristics of the extant Southern Ocean fauna is its resiliency to survive glacial processes of the Quaternary. These climatic events produced catastrophic habitat reductions and forced some marine benthic species to move, adapt or go extinct. The marine benthic species inhabiting the Antarctic upper continental shelf faced the Quaternary glaciations with different strategies that drastically modified population sizes and thus affected the amount and distribution of intraspecific genetic variation. Here we present new genetic information for the most conspicuous regular sea urchin of the Antarctic continental shelf, Sterechinus neumayeri. We studied the patterns of genetic diversity and structure in this broadcast-spawner across three Antarctic regions: Antarctic Peninsula, the Weddell Sea and Adélie Land in East Antarctica. Genetic analyses based on mitochondrial and nuclear markers suggested that S. neumayeri is a single genetic unit around the Antarctic continent. The species is characterized by low levels of genetic diversity and exhibits a typical star-like haplotype genealogy that supports the hypothesis of a single in situ refugium. Based on two mutation rates standardized for this genus, the Bayesian Skyline plot analyses detected a rapid demographic expansion after the Last Glacial Maximum. We propose a scenario of rapid postglacial expansion and recolonization of Antarctic shallow areas from a less ice-impacted refugium where the species survived the LGM. Considering the patterns of genetic diversity and structure recorded in the species, this refugium was probably located in East Antarctica.

Genetic structure and demographic inference of the regular sea urchin Sterechinus neumayeri (Meissner, 1900) in the Southern Ocean: The role of the last glaciation

PubMed Central

Gérard, Karin; González-Wevar, Claudio; Maturana, Claudia; Féral, Jean-Pierre; David, Bruno; Saucède, Thomas; Poulin, Elie

2018-01-01

One of the most relevant characteristics of the extant Southern Ocean fauna is its resiliency to survive glacial processes of the Quaternary. These climatic events produced catastrophic habitat reductions and forced some marine benthic species to move, adapt or go extinct. The marine benthic species inhabiting the Antarctic upper continental shelf faced the Quaternary glaciations with different strategies that drastically modified population sizes and thus affected the amount and distribution of intraspecific genetic variation. Here we present new genetic information for the most conspicuous regular sea urchin of the Antarctic continental shelf, Sterechinus neumayeri. We studied the patterns of genetic diversity and structure in this broadcast-spawner across three Antarctic regions: Antarctic Peninsula, the Weddell Sea and Adélie Land in East Antarctica. Genetic analyses based on mitochondrial and nuclear markers suggested that S. neumayeri is a single genetic unit around the Antarctic continent. The species is characterized by low levels of genetic diversity and exhibits a typical star-like haplotype genealogy that supports the hypothesis of a single in situ refugium. Based on two mutation rates standardized for this genus, the Bayesian Skyline plot analyses detected a rapid demographic expansion after the Last Glacial Maximum. We propose a scenario of rapid postglacial expansion and recolonization of Antarctic shallow areas from a less ice-impacted refugium where the species survived the LGM. Considering the patterns of genetic diversity and structure recorded in the species, this refugium was probably located in East Antarctica. PMID:29874287

New research on the origin of mottled clay in Quaternary basins in the coastal area of south China

NASA Astrophysics Data System (ADS)

Wang, Jing; Chen, Zhen; Gao, Quanzhou; Chen, Guoneng

2018-06-01

Last Glacial Maximum (LGM) mottled clay occurs widely in Late Quaternary basins in south China coastal areas. Current research attributes its origin to exposure weathering of Late Pleistocene marine/fluvial deposits during the LGM. However, field data suggest that this is not the case as there is no gradual transition in lithology, grain size, structure and material composition among these layers. Instead, the mottled clay possesses sedimentary characteristics of exotic dust. In this study, three typical drill cores in the Pearl River Delta were studied using grain size analysis, diffuse reflection spectroscopy (DRS) and geochemical analysis to ascertain the clay's sedimentary characteristics and origin. Grain size distribution patterns and parameters of the mottled clay were similar to those of a typical loess, indicating aeolian origin. In DRS curves, the peak height of hematite > goethite, indicating that the mottled clay had not experienced strong hydration and constitutes a continental product. This conforms to a typical loess but differs from the underlying marine/fluvial deposits. The chemical composition of the mottled clay was homogeneous in the vertical and planar directions. Upper continental crust (UCC) normalized curves of major and trace elements of the mottled clay were close to the average UCC and were consistent with typical aeolian deposits. The spatial and temporal distribution characteristics and relationship with the underlying layer suggest that the mottled clay was a loess-like deposit during the LGM and its mottled structure originated from strong modification of oxidation during the postglacial period after homogeneous dust had accumulated.

Record of the Late Devonian Hangenberg global positive carbon-isotope excursion in an epeiric sea setting: Carbonate production, organic-carbon burial and paleoceanography during the late Famennian

USGS Publications Warehouse

Cramer, Bradley D.; Saltzman, Matthew R.; Day, J.E.; Witzke, B.J.

2008-01-01

Latest Famennian marine carbonates from the mid-continent of North America were examined to investigate the Late Devonian (very late Famennian) Hangenberg positive carbon-isotope (??13 Ccarb) excursion. This global shift in the ?? 13C of marine waters began during the late Famennian Hangenberg Extinction Event that occurred during the Middle Siphonodella praesulcata conodont zone. The post-extinction recovery interval spans the Upper S. praesulcata Zone immediately below the Devonian-Carboniferous boundary. Positive excursions in ?? 13 Ccarb are often attributed to the widespread deposition of organic-rich black shales in epeiric sea settings. The Hangenberg ??13 Ccarb excursion documented in the Louisiana Limestone in this study shows the opposite trend, with peak ??13 Ccarb values corresponding to carbonate production in the U.S. mid-continent during the highstand phase of the very late Famennian post-glacial sea level rise. Our data indicate that the interval of widespread black shale deposition (Hangenberg Black Shale) predates the peak isotope values of the Hangenberg ??13 Ccarb excursion and that peak values of the Hangenberg excursion in Missouri are not coincident with and cannot be accounted for by high Corg burial in epeiric seas. We suggest instead that sequestration and burial of Corg in the deep oceans drove the peak interval of the ??13Ccarb excursion, as a result of a change in the site of deep water formation to low-latitude epeiric seas as the global climate shifted between cold and warm states.

The origin of islands in the Kandalaksha Gulf of the White Sea: joint work of internal and external geodynamic processes

NASA Astrophysics Data System (ADS)

Kosevich, Natalia; Romanovskaya, Maria

2016-04-01

The modern White Sea basin is a part of the encounter zone between the East European Platform and of the Fennoscandian Shield. The Kandalaksha Gulf in its northwest lies on the Mesoarchean-Paleoproterozoic structure known as the White Sea Shift Belt. In the Oligocene, it entered its neotectonic stage. Geologically, there are two structural storeys beneath the seafloor of the Kandalaksha Gulf: 1) crystalline bedrock of the Archean White Sea complex; 2) a cover of sediment consisting of three layers: Riphean sandstones, terrigenous Vendian deposits; a cloak of Pleistocene and Holocene deposits and sediments - glacial drifts, transitional glaciomarine sediments and purely marine sediments. The modern White Sea is a young basin formed just 10 to 12 ka. The geological and geomorphic history of the White Sea region was very complicated, with various and often conflicting tectonic movements. Besides the postglacial isostatic rise of Scandinavia amounted to some 100 meters in the White Sea area. The White Sea has numerous islands that are very different in the geological-geomorphological and genetic senses because their origin is the result of interactions between various endogenous and exogenous processes. Large and detailed scale geological and morphological researches of the islands at the southern and northern coast of the Kandalaksha Gulf have been carried out. Landforms of the islands were produced by the joint effects of such processes as (1) glacial-tectonic effects and marine wave action, (2) tidal and surge effects; (3) glacial-tectonic, marine, and gravity effects, and (4) glacial-tectonic, marine, lake, and biogenic effects (Kosevich, 2015). The relief structure of the islands has the following regularities: 1) structures of the northern coast islands are more often landforms that are composed of loose deposits with small sites of structural denudation residual outcrops; 2) the structures of the southern coast islands are typically combinations of loose deposits and bedrock outcrops; structural denudation landforms dominate over the marine and biogenic landforms in this case, rocky surfaces of these islands predominate over others. The relief of islands is a combination of smoothed rounded top bedrock surfaces (massifs) with subhorizontal sites that are covered with loose marine deposits. Analysis of the spatial distribution of the genetic types of islands in the Kandalaksha Gulf has revealed that in the apical part of the gulf all genetic types of islands occur, while upon approaching the mouth, one type (tectonic-glacial-accumulative-denudation with marine reworking) becomes predominant. Thus, geological, structural, geomorphic features of Kandalahksha Gulf islands are the results of the complex interaction of the internal and external geodynamic processes. Kosevich N. Geological-geomorphological types of islands in the Kandalaksha Gulf, White Sea. Moscow Univ. Geol.Bull., 2015, vol. 70, N 4. P. 318-326.

A mistletoe tale: postglacial invasion of Psittacanthus schiedeanus (Loranthaceae) to Mesoamerican cloud forests revealed by molecular data and species distribution modeling.

PubMed

Ornelas, Juan Francisco; Gándara, Etelvina; Vásquez-Aguilar, Antonio Acini; Ramírez-Barahona, Santiago; Ortiz-Rodriguez, Andrés Ernesto; González, Clementina; Mejía Saules, María Teresa; Ruiz-Sanchez, Eduardo

2016-04-12

Ecological adaptation to host taxa is thought to result in mistletoe speciation via race formation. However, historical and ecological factors could also contribute to explain genetic structuring particularly when mistletoe host races are distributed allopatrically. Using sequence data from nuclear (ITS) and chloroplast (trnL-F) DNA, we investigate the genetic differentiation of 31 Psittacanthus schiedeanus (Loranthaceae) populations across the Mesoamerican species range. We conducted phylogenetic, population and spatial genetic analyses on 274 individuals of P. schiedeanus to gain insight of the evolutionary history of these populations. Species distribution modeling, isolation with migration and Bayesian inference methods were used to infer the evolutionary transition of mistletoe invasion, in which evolutionary scenarios were compared through posterior probabilities. Our analyses revealed shallow levels of population structure with three genetic groups present across the sample area. Nine haplotypes were identified after sequencing the trnL-F intergenic spacer. These haplotypes showed phylogeographic structure, with three groups with restricted gene flow corresponding to the distribution of individuals/populations separated by habitat (cloud forest localities from San Luis Potosí to northwestern Oaxaca and Chiapas, localities with xeric vegetation in central Oaxaca, and localities with tropical deciduous forests in Chiapas), with post-glacial population expansions and potentially corresponding to post-glacial invasion types. Similarly, 44 ITS ribotypes suggest phylogeographic structure, despite the fact that most frequent ribotypes are widespread indicating effective nuclear gene flow via pollen. Gene flow estimates, a significant genetic signal of demographic expansion, and range shifts under past climatic conditions predicted by species distribution modeling suggest post-glacial invasion of P. schiedeanus mistletoes to cloud forests. However, Approximate Bayesian Computation (ABC) analyses strongly supported a scenario of simultaneous divergence among the three groups isolated recently. Our results provide support for the predominant role of isolation and environmental factors in driving genetic differentiation of Mesoamerican parrot-flower mistletoes. The ABC results are consistent with a scenario of post-glacial mistletoe invasion, independent of host identity, and that habitat types recently isolated P. schiedeanus populations, accumulating slight phenotypic differences among genetic groups due to recent migration across habitats. Under this scenario, climatic fluctuations throughout the Pleistocene would have altered the distribution of suitable habitat for mistletoes throughout Mesoamerica leading to variation in population continuity and isolation. Our findings add to an understanding of the role of recent isolation and colonization in shaping cloud forest communities in the region.

Postglacial Human resilience and susceptibility to abrupt climate change new insights from Star Carr

NASA Astrophysics Data System (ADS)

Blockley, Simon; Abrook, Ashley; Bayliss, Alex; Candy, Ian; Conneller, Chantal; Darvill, Chris; Deeprose, Laura; Kearney, Rebecca; Langdon, Pete; Langdon Langdon, Cath; Lincoln, Paul; Macleod, Alison; Matthews, Ian; Palmer, Adrian; Schreve, Danielle; Taylor, Barry; Milner, Nicky

2017-04-01

We know little about the lives of the early humans who lived during the early Postglacial period (the Lateglacial and Early Holocene), a time characterised by abrupt climate change after 16,000, which includes a series of abrupt climatic transitions linked to the reorganisation of the global environment after the glacial maximum and the last major global warming event at the onset of the Holocene. The hunter-gatherers who lived during the early Postglacial have been characterised as highly mobile, dispersed and living within small groups, and there is much debate as to how they adapted to climatic and environmental change: did they move in response to climatic transitions (and if so what was the climatic threshold), or instead adapt their lifeways to the new environmental conditions? A key area for examining these ideas is the British Isles as it sits on the Atlantic fringe of Northwest Europe with a climate that is highly responsive to the wider climate forcing experienced in the northern Hemisphere. Furthermore, in this period, Britain is directly linked to continental Europe due to lowered global sea levels allowing for the ease of human migration in and out of this region. In general the British record has been seen as being dominated by abandonment and reoccupation in the Postglacial during periods of climatic transition with hunter-gatherer mobility being closely linked to the prevailing environment. Recent discoveries at the Early Mesolithic site of Star Carr and surrounding area, linked to local and regional climate records, based on isotopic, chironomid and pollen proxy data and dated at high chronological resolution, offer a new picture. Postglacial human occupation of the area commences at the Pleistocene/Holocene transition but is short lived and appears to end close to the Pre-Boreal Oscillation, However, this is followed by a period where hunter-gatherers occupy Star Carr and settle and invest time and effort into building huts and large scale wooden structures, with evidence for occupation that spans hundreds of years. This phase of occupation at Star Carr is sustained and crosses a period of abrupt climatic instability as significant as any in the Early Holocene record of the region. This reduced mobility implies that the inhabitants of the region around Star Carr had adapted to and, consequently, had developed a resilience to an unstable early Holocene environment and landscape despite clear evidence of significant climatic transitions during the Star Carr phase.

The glacimarine sediment budget of the Nares Strait-Petermann Fjord area since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Jakobsson, M.; Hogan, K.; Mayer, L. A.; Mix, A. C.; Nielsen, T.; Kamla, E.; Stranne, C.; Eriksson, B.; Jerram, K.

2016-12-01

During the Petermann 2015 Expedition of the Swedish icebreaker Oden more than 6500 line-km of high-resolution chirp sub-bottom profiles (2-7 kHz) were acquired in Petermann Fjord and Nares Strait in the area immediately outside of the fjord. The sub-bottom profiles reveal a highly-variable distribution of post-glacial sediment that appears to be largely controlled by the rugged relief of the underlying bedrock. Sediment thicknesses are between 0-60 m above bedrock and comprise predominantly acoustically-stratified, homogeneous to transparent acoustic facies. In Petermann Fjord itself unlithified sediment cover typically comprises two units: an underlying acoustically-transparent unit overlain by an acoustically-stratified unit. Both of these units are conformable over scoured and fairly flat bedrock terrain; small basins are present only locally. Outside of the fjord are a few local sedimentary basins containing up to 40 m of stratified basin-fill deposits, and several areas of stacked mass-flow deposits. Glacial lineations both in the fjord and Nares Strait are formed in an acoustically-homogenous unit that underlies stratified and transparent units. In addition to the sub-bottom profiles, approximately 780 line-km of 2D seismic reflection profiles were acquired using an airgun (210 cu in.) and a 300-m long streamer. These profiles have allowed us to map full unlithified sediment thicknesses down to basement in the area. Here we present the results of this mapping and we calculate the volumes of a prominent grounding-zone wedge at the mouth of Petermann Fjord, and smaller GZWs in Kennedy Channel. These features demarcate former still-stand positions of grounded ice retreating through this system, both towards the present-day grounding line of Petermann Glacier and southwards through Nares Strait. Post-glacial sediment volumes are also calculated and the sedimentary processes responsible for their distribution examined. These data, when combined with chronological information, will provide sediment fluxes through the Petermann system and help us to identify how the system has responded to a past global warming event, namely the last deglaciation. This is particularly important in light of the recent thinning and acceleration of NW Greenland's marine-terminating outlet glaciers at present.

Post-glacial variations of sea ice cover and river discharge in the western Laptev Sea (Arctic Ocean) - a high-resolution study over the last 18 ka

NASA Astrophysics Data System (ADS)

Hörner, Tanja; Stein, Ruediger; Fahl, Kirsten

2015-04-01

Here, we provide a high-resolution reconstruction of sea-ice cover variations in the western Laptev Sea, a crucial area in terms of sea-ice production in the Arctic Ocean and a region characterized by huge river discharge. Furthermore, the shallow Laptev Sea was strongly influenced by the post-glacial sea-level rise that should also be reflected in the sedimentary records. The sea Ice Proxy IP25 (Highly-branched mono-isoprenoid produced by sea-ice algae; Belt et al., 2007) was measured in two sediment cores from the western Laptev Sea (PS51/154, PS51/159) that offer a high-resolution composite record over the last 18 ka. In addition, sterols are applied as indicator for marine productivity (brassicasterol, dinosterol) and input of terrigenous organic matter by river discharge into the ocean (campesterol, ß-sitosterol). The sea-ice cover varies distinctly during the whole time period and shows a general increase in the Late Holocene. A maximum in IP25 concentration can be found during the Younger Dryas. This sharp increase can be observed in the whole circumarctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). Interestingly, there is no correlation between elevated numbers of ice-rafted debris (IRD) interpreted as local ice-cap expansions (Taldenkova et al. 2010), and sea ice cover distribution. The transgression and flooding of the shelf sea that occurred over the last 16 ka in this region, is reflected by decreasing terrigenous (riverine) input, reflected in the strong decrease in sterol (ß-sitosterol and campesterol) concentrations. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38 (1), 16e27. Taldenkova, E., Bauch, H.A., Gottschalk, J., Nikolaev, S., Rostovtseva, Yu., Pogodina, I., Ya, Ovsepyan, Kandiano, E., 2010. History of ice-rafting and water mass evolution at the northern Siberian continental margin (Laptev Sea) during Late Glacial and Holocene times. Quaternary Science Reviews 29 (27-28), 3919-3935.

High-resolution record of last post-glacial variations of sea-ice cover and river discharge in the western Laptev Sea (Arctic Ocean)

NASA Astrophysics Data System (ADS)

Stein, R. H.; Hörner, T.; Fahl, K.

2014-12-01

Here, we provide a high-resolution reconstruction of sea-ice cover variations in the western Laptev Sea, a crucial area in terms of sea-ice production in the Arctic Ocean and a region characterized by huge river discharge. Furthermore, the shallow Laptev Sea was strongly influenced by the post-glacial sea-level rise that should also be reflected in the sedimentary records. The sea Ice Proxy IP25 (Highly-branched mono-isoprenoid produced by sea-ice algae; Belt et al., 2007) was measured in two sediment cores from the western Laptev Sea (PS51/154, PS51/159) that offer a high-resolution composite record over the last 18 ka. In addition, sterols are applied as indicator for marine productivity (brassicasterol, dinosterol) and input of terrigenous organic matter by river discharge into the ocean (campesterol, ß-sitosterol). The sea-ice cover varies distinctly during the whole time period and shows a general increase in the Late Holocene. A maximum in IP25 concentration can be found during the Younger Dryas. This sharp increase can be observed in the whole circumarctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). Interestingly, there is no correlation between elevated numbers of ice-rafted debris (IRD) interpreted as local ice-cap expansions (Taldenkova et al. 2010), and sea ice cover distribution. The transgression and flooding of the shelf sea that occurred over the last 16 ka in this region, is reflected by decreasing terrigenous (riverine) input, reflected in the strong decrease in sterol (ß-sitosterol and campesterol) concentrations. ReferencesBelt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38 (1), 16e27. Taldenkova, E., Bauch, H.A., Gottschalk, J., Nikolaev, S., Rostovtseva, Yu., Pogodina, I., Ya, Ovsepyan, Kandiano, E., 2010. History of ice-rafting and water mass evolution at the northern Siberian continental margin (Laptev Sea) during Late Glacial and Holocene times. Quaternary Science Reviews 29 (27-28), 3919-3935.

The sedimentary evolution of the Celtic Sea during Marine Isotope Stages 1 and 2

NASA Astrophysics Data System (ADS)

Lockhart, Edward; Scourse, James; Van Landeghem, Katrien; Praeg, Daniel; Mellett, Claire; Huws, Dei; Saher, Margot; Benetti, Sara

2017-04-01

During the Last Glacial Maximum (LGM), the Celtic Sea was partially glaciated by the Irish Sea Ice Stream and is considered to have subsequently experienced a high-energy post-glacial transgression. The combination of these events resulted in the deposition, reworking and erosion of a wide range of sediment types to produce the upper stratigraphy of the shelf, including the world's largest submarine elongated ridges. These geomorphic features dominate the shelf and have been previously interpreted to have formed as a result of the tidal reworking of shelf deposits during transgression, despite not having been directly dated. Shelf-wide high-resolution geophysical data, and vibrocores, collected as part of the BRITICE-CHRONO Project, provide new information on relationships between seismic and shallow sedimentary units. A regionally extensive near-surface reflector, cored in several locations, correlates to a gravel/shell layer with an erosive base, unconformably overlying fine-grained LGM glacial sediments with undrained shear strengths in excess of 120 kPa, and in places exhibiting visibly deformed laminations. Geotechnical tests suggest these sediments to be over-consolidated, and we propose that these properties and the observed deformation can only be explained by subglacial reworking under a re-advancing Irish Sea Ice Stream, a scenario never before evidenced in reconstructions of Celtic Sea glaciation. Previous reconstructions propose a single advance-retreat cycle; therefore, a re-advance during a time of inferred retreat would represent a significant change in glacial dynamics. Seismic reflection profiles show that the regionally continuous gravel/shell layer appears to form an undulating palaeo-topography, possibly influenced by the geotechnical properties of the deposits below, on which the large surface ridges are formed. The presence of a regionally continuous reflection surface truncating LGM glacial sediments would suggest a significant erosion event after glacial deposition occurred, possibly representing transgression. This suggests that the large surface ridges may be of post-glacial tidal origin, but with significant sediment supply and morphological control influenced by the glaciation of the Celtic Sea.

Palynological tracers of eustatic and climatic changes in the Late Ordovician on the North Gondwanan Margin

NASA Astrophysics Data System (ADS)

Le Hérissé, A.; Vecoli, M.

2003-04-01

The short-lived Hirnantian glacio-eustatic interval (1 My or less) caused about 60 per cent loss of total marine animal genera. This icehouse climate is also responsible for significant changes on the evolution of the plankton and the distribution of related microfossil assemblages, from pre-glacial to post-glacial episodes. This is clearly confirmed on different upper Ordovician sections from various paleogeographic location on the North Gondwanan margin. The effects of the glaciation did not correspond exactly to a cataclysmic event, because the palynomorphs do not show accelerated rates of extinction, in the inhospitable environment. It could also be noted that the origins of the Silurian communities are rooted in the upper Ordovician prior to the glaciation, with appearance of precursors (or -ahead of time-) forms, that diversified later in the Silurian. Nevertheless, the harsh climatic conditions associated to sea-level drop, caused a reduction in the number of taxa, with a scenario composed of three separate critical events: 1. a selective survival of ubiquitous taxa which are tolerant to the sea-level drawdown and of few taxa that appear specifically adapted to cold environments (Rawtheyan-early Hirnantian); 2. an adaptation of the sympagic microflora, to the variations of the sea-ice cover during deglaciation, including polymorphism and speciations (Hirnantian); 3. a slow recovery acompanying the climatic restoration and transgression in the latest Ordovician and early Silurian. Modifications in abundance and diversity of the microfossil assemblages, in the percentages of reworked elements and of amorphic organic matter are interpreted as evidence of a series of advances and retreats of the continental ice, of important changes of sea-surface conditions, of differences in the rate of melting of the icebergs during the deglaciation, as well as post-glacial isostatic rebounds. Our investigation demonstrates that the analysis of the evolution of palynomorph groups and phytoplanctonic responses to varying palaeoenvironmental conditions (as for more recent analogues) has important applications to the study of climatic changes, the deglaciation history and the sedimentary environment of the late Ordovician in a broader context.

IOC/WMO Workshop on Marine Pollution Monitoring (3rd, New Delhi, India, February 11-15, 1980). Summary Report. Workshop Report No. 22.

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Paris (France). Intergovernmental Oceanographic Commission.

Provided is a summary report of the third IOC/WMO (Intergovernmental Oceanographic Commission/World Meteorological Organization) workshop of marine pollution monitoring. Summaries are presented in nine sections, including: (1) workshop opening; (2) welcoming addresses; (3) reports on the Marine Pollution (Petroleum) Monitoring Pilot Project…

Constraints on the sources of branched GDGTs in open ocean sediments: dust transport or in situ production?

NASA Astrophysics Data System (ADS)

Weijers, J.; Schefuss, E.; Kim, J.; Sinninghe Damsté, J. S.; Schouten, S.

2012-12-01

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are membrane lipids synthesized by soil bacteria that, upon soil erosion, are transported by rivers to the ocean where they accumulate in the near shore sedimentary archive. The degrees of cyclisation (CBT) and methylation (MBT) of these compounds have been shown to relate to soil pH and annual mean air temperature [1]. Therefore, brGDGTs in near shore sedimentary archives can be used to estimate past continental air temperatures and enable a direct comparison of these to marine sea surface temperature estimates obtained from the same samples. In addition, brGDGT abundance relative to crenarchaeol, an isoprenoid GDGT synthesized by marine pelagic Thaumarchaeota, quantified in the branched vs. isoprenoid tetraether (BIT) index, is an indicator of the relative input of soil organic matter in near shore sediments [2]. High BIT values near river outflows testify of relative strong soil organic matter input and generally the BIT index will decrease off shore to values near 0, the marine end-member value. Even in remote open ocean sediments, however, the BIT index will rarely reach 0 as small amounts of brGDGTs are often present. The occurrence of these brGDGTs in open marine settings might be a result of i) dust input, ii) sediment dispersion from near coastal areas, or iii) in situ production in marine sediments. In order to constrain the origin of branched GDGTs in open marine sediments we analyzed i) atmospheric dust samples taken along an equatorial African coastal transect, ii) marine surface waters near and away of the Congo river outflow, iii) a series of surface sediments at and around the Congo deep sea fan, and iv) a series of open marine surface sediments from different oceans with BIT values < 0.08. Our results show that brGDGTs are present, though in relative low amounts, in dust. Their distribution resembles that of soil input as also found in the Congo deep sea fan, with MBT and CBT values that could be representative of tropical African soils. Strikingly, BIT indices are much lower than expected for soils (0.15-0.42), likely as a result of sea spray on the dust filters. Open ocean sediments, on the contrary, are typically characterized by relative high amounts of cyclopentane containing brGDGTs resulting in low CBT values ranging from -0.4 - 0.8. These values are similarly low as reported earlier in marine sediments near Svalbard [3] and in the East China Sea [4], for which in situ production was invoked. Thus, brGDGT transport by dust does seem possible, though quantities are low. Since open ocean brGDGT distributions are markedly different from those in soils and dust, the latter is most likely not a significant source. Our results indicate that production of brGDGTs in ocean sediments, though in relative low amounts, is much more widespread than previously thought. This emphasizes that the MBT-CBT proxy for continental air temperature should only be used at locations where soil organic matter input is significant as evidenced by high BIT indices. References: [1] Weijers J.W.H. et al. (2007) Geochmim. Cosmochim. Acta 71, 703-713. [2] Hopmans E.C. et al. (2004) Earth Planet. Sci. Lett. 224, 107-116. [3] Peterse F. et al. (2009) Org. Geochem. 40, 692-699. [4] Zhu C. Et al. (2011) Org. Geochem. 42, 376-386.

Gulf Coast Deep Water Port Facilities Study. Appendix D. Adverse Environmental Effects.

DTIC Science & Technology

1973-04-01

mds 2. Thigmotropic effect of submerged structures 3. Attachment or shelter for marine organisms 4. Gain of sheltered habitat (lee of islands) 5...marshplants Bay margin marine grass, clams, snails and blue crab Grass flats marine grass, clams, snails, black drum and t other fish Open bay with tidal...surrounding area. F. CONCLUSION The most direct and easily understood effects of dredging projects on marine biota are: I) the destruction and removal of

Biostratigraphy and paleoecology of the Burdigalian-Serravallian sediments in Wadi Sudr (Gulf of Suez, Egypt): comparison with the Central Paratethys evolution

NASA Astrophysics Data System (ADS)

Ied, Ibrahim M.; Holcová, Katarína; Abd-Elshafy, Ezzat

2011-06-01

Two main Miocene facies were recorded in the Gulf of Suez area: a deep marine and a coastal facies. The analysed sections in the Wadi Sudr area belong to the marine facies. The Lower Miocene (Burdigalian) is represented by coastal, shallow marine sediments, rich in coral, algae, gastropods and large pectinids followed by Langhian open marine sediments and Serravallian lagoonal carbonates. The open marine sediments contain well preserved planktonic and benthic foraminifers and abundant ostracods. The parts of the sections containing foraminifers have been correlated with three planktonic foraminiferal zones (Praeorbulina glomerosa Zone, Orbulina Zone and Globorotalia praemenardii-Globorotalia peripheroronda Zone). Two benthic ecozones were defined (Heterolepa dutemplei-Laevidentalina elegans Zone and Bolivina compressa-Elphidium spp. Zone). Two cycles of sea-level changes can be distinguished and correlated with global sea-level cycles Bur5/Lan1 and Ser1. The first (Langhian) cycle culminated in open marine sublittoral to upper bathyal well aerated sediments. The second (Serravallian) cycle was shallower, littoral suboxic sediments were overlaid by euryhaline carbonates. The studied foraminifera-bearing sediments can be correlated with the lower and Middle Badenian of the Central Paratethys. Though the area of the Gulf of Suez and the Central Paratethys were situated in different climatic zones, and influenced by different tectonic events, the main paleoenvironmental events (sea-level changes, oxygen decrease, salinity changes) are comparable. This correspondence shows that the decisive factors triggering these events were global climatic events.

77 FR 29924 - Drawbridge Operation Regulation; Alabama River, AL

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-21

... maintained in the closed-to-navigation position, opening only for the passage of marine traffic. The bridge... of openings of the drawbridge, an average of one opening per year, the bridge owner requested a... schedule a bridge opening. Under this proposed rule, the MNBR will also remain in the closed-to-navigation...

Nucleotide variation in the mitochondrial genome provides evidence for dual routes of postglacial recolonization and genetic recombination in the northeastern brook trout (Salvelinus fontinalis).

PubMed

Pilgrim, B L; Perry, R C; Barron, J L; Marshall, H D

2012-09-26

Levels and patterns of mitochondrial DNA (mtDNA) variation were examined to investigate the population structure and possible routes of postglacial recolonization of the world's northernmost native populations of brook trout (Salvelinus fontinalis), which are found in Labrador, Canada. We analyzed the sequence diversity of a 1960-bp portion of the mitochondrial genome (NADH dehydrogenase 1 gene and part of cytochrome oxidase 1) of 126 fish from 32 lakes distributed throughout seven regions of northeastern Canada. These populations were found to have low levels of mtDNA diversity, a characteristic trait of populations at northern extremes, with significant structuring at the level of the watershed. Upon comparison of northeastern brook trout sequences to the publicly available brook trout whole mitochondrial genome (GenBank AF154850), we infer that the GenBank sequence is from a fish whose mtDNA has recombined with that of Arctic charr (S. alpinus). The haplotype distribution provides evidence of two different postglacial founding groups contributing to present-day brook trout populations in the northernmost part of their range; the evolution of the majority of the haplotypes coincides with the timing of glacier retreat from Labrador. Our results exemplify the strong influence that historical processes such as glaciations have had on shaping the current genetic structure of northern species such as the brook trout.

Stratigraphic and morphologic signatures of continental shelves, IGC 2016, Cape Town: an introduction

NASA Astrophysics Data System (ADS)

Green, A. N.; Cooper, J. A. G.

2018-02-01

This special issue of Geo-Marine Letters comprises seven contributions to the session "Stratigraphic and morphologic signatures of continental shelves" of the 35th International Geological Congress held in Cape Town (Republic of South Africa) on 27 August-4 September 2016. There is an additional article not presented at the conference but falling into the same general theme. The guest editors are A.N. Green and J.A.G. Cooper. The eight articles address several contemporary themes in continental shelf geology. They include the role of antecedent conditioning on the development of shelf stratigraphy and geomorphology; erosion of submerged shorelines and their preservation during (stepped) postglacial sea-level rise; the role of glacial processes (e.g. iceberg scouring during ice-sheet retreat); and the utility of archival data in addressing contemporary issues such as Holocene climate change and global oceanographic circulation systems. The continental shelf holds important information for understanding past and present global circulation and earth-ice-atmosphere interactions including sea-level change. It is hoped that these themes will spur further research that is slowly coming to the fore in several new and innovative mapping and exploration programmes emerging from an increasing number of coastal nations.

King penguin demography since the last glaciation inferred from genome-wide data.

PubMed

Trucchi, Emiliano; Gratton, Paolo; Whittington, Jason D; Cristofari, Robin; Le Maho, Yvon; Stenseth, Nils Chr; Le Bohec, Céline

2014-07-22

How natural climate cycles, such as past glacial/interglacial patterns, have shaped species distributions at the high-latitude regions of the Southern Hemisphere is still largely unclear. Here, we show how the post-glacial warming following the Last Glacial Maximum (ca 18 000 years ago), allowed the (re)colonization of the fragmented sub-Antarctic habitat by an upper-level marine predator, the king penguin Aptenodytes patagonicus. Using restriction site-associated DNA sequencing and standard mitochondrial data, we tested the behaviour of subsets of anonymous nuclear loci in inferring past demography through coalescent-based and allele frequency spectrum analyses. Our results show that the king penguin population breeding on Crozet archipelago steeply increased in size, closely following the Holocene warming recorded in the Epica Dome C ice core. The following population growth can be explained by a threshold model in which the ecological requirements of this species (year-round ice-free habitat for breeding and access to a major source of food such as the Antarctic Polar Front) were met on Crozet soon after the Pleistocene/Holocene climatic transition. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Chronology of Postglacial Eruptive Activity and Calculation of Eruption Probabilities for Medicine Lake Volcano, Northern California

USGS Publications Warehouse

Nathenson, Manuel; Donnelly-Nolan, Julie M.; Champion, Duane E.; Lowenstern, Jacob B.

2007-01-01

Medicine Lake volcano has had 4 eruptive episodes in its postglacial history (since 13,000 years ago) comprising 16 eruptions. Time intervals between events within the episodes are relatively short, whereas time intervals between the episodes are much longer. An updated radiocarbon chronology for these eruptions is presented that uses paleomagnetic data to constrain the choice of calibrated ages. This chronology is used with exponential, Weibull, and mixed-exponential probability distributions to model the data for time intervals between eruptions. The mixed exponential distribution is the best match to the data and provides estimates for the conditional probability of a future eruption given the time since the last eruption. The probability of an eruption at Medicine Lake volcano in the next year from today is 0.00028.

Time-Variable Gravity: The Low-Degree Components and their Connections with Geophysical/Climatic Changes

NASA Technical Reports Server (NTRS)

Cox, Christopher M.; Chao, Benjamin F.; Au, Andrew Y.

2004-01-01

The oblateness of the Earth's gravity field, J2, has long been observed to undergo a slight decrease due to post-glacial rebound of the mantle. Sometime around 1998 this trend reversed quite suddenly. This reversal persisted until 2001, at which point the atmosphere-corrected time series appears to have reversed yet again. Presently, the time series appears to be returning to the value that would nominally have been reached had the anomaly not occurred. This anomaly signifies a large interannual change in global mass distribution whose J2 effect overshadows that of the post-glacial rebound over such timescales. A number of possible causes have been considered, with oceanic mass redistribution as the leading candidate although other effects, such as glacial melting and core effects may be contributing.

Phylogenetic comparisons of a coastal bacterioplankton community with its counterparts in open ocean and freshwater systems.

PubMed

Rappé; Vergin; Giovannoni

2000-09-01

In order to extend previous comparisons between coastal marine bacterioplankton communities and their open ocean and freshwater counterparts, here we summarize and provide new data on a clone library of 105 SSU rRNA genes recovered from seawater collected over the western continental shelf of the USA in the Pacific Ocean. Comparisons to previously published data revealed that this coastal bacterioplankton clone library was dominated by SSU rRNA gene phylotypes originally described from surface waters of the open ocean, but also revealed unique SSU rRNA gene lineages of beta Proteobacteria related to those found in clone libraries from freshwater habitats. beta Proteobacteria lineages common to coastal and freshwater samples included members of a clade of obligately methylotrophic bacteria, SSU rRNA genes affiliated with Xylophilus ampelinus, and a clade related to the genus Duganella. In addition, SSU rRNA genes were recovered from such previously recognized marine bacterioplankton SSU rRNA gene clone clusters as the SAR86, SAR11, and SAR116 clusters within the class Proteobacteria, the Roseobacter clade of the alpha subclass of the Proteobacteria, the marine group A/SAR406 cluster, and the marine Actinobacteria clade. Overall, these results support and extend previous observations concerning the global distribution of several marine planktonic prokaryote SSU rRNA gene phylotypes, but also show that coastal bacterioplankton communities contain SSU rRNA gene lineages (and presumably bacterioplankton) shown previously to be prevalent in freshwater habitats.

Feeding habits of amphipods (Crustacea: Malacostraca) from shallow soft bottom communities: Comparison between marine caves and open habitats

NASA Astrophysics Data System (ADS)

Navarro-Barranco, Carlos; Tierno-de-Figueroa, José Manuel; Guerra-García, José Manuel; Sánchez-Tocino, Luis; García-Gómez, José Carlos

2013-04-01

Marine caves are environments of great interest since the organisms that inhabit them are forced to develop specific adaptations to high constraint conditions. Because of some of these particular conditions, such as light absence or oligotrophy, it can be expected that feeding strategies into caves differ from that present outside them. Nevertheless, no studies have been done to compare the trophic structure of marine caves and open habitats, at least for amphipod communities, considering their importance both inside and outside of the caves. In this study, the diet of the dominant amphipod species living on shallow sediments, both inside and outside of six marine caves in western Mediterranean, was characterized. Thereby, the gut content of 17 amphipod species was studied, being this study the first attempt to establish the feeding habit of most of these species. Analysis of digestive contents of the species showed that amphipod diet is less diverse in sediments than in other environments, such as algae and seagrasses. No herbivorous species were found in the sediment and carnivorous amphipods showed a little variety of prey, feeding mainly on crustaceans. Differences in the trophic structure were also found between marine caves and open habitats sediments: while outside the caves detritivorous was the dominant group (both in number of species and number of individuals), amphipods mainly play the role of carnivorous inside the caves. No detritivorous species were found into the caves, where carnivorous represents almost 60% of amphipods species and more than 80% of amphipod individuals. This pattern obtained in amphipods differ from the general trend observed in marine cave organisms, for which a generalist diet, such as omnivory, usually is an advantage in these oligotrophic conditions. The possible causes of this pattern are discussed.

Micropaleontologic record of late Pliocene and Quaternary paleoenvironments in the northern Albemarle Embayment, North Carolina, U.S.A.

USGS Publications Warehouse

Culver, S.J.; Farrell, K.M.; Mallinson, D.J.; Horton, B.P.; Willard, D.A.; Thieler, E.R.; Riggs, S.R.; Snyder, S.W.; Wehmiller, J.F.; Bernhardt, C.E.; Hillier, C.

2008-01-01

Micropaleontological data provide a strong actualistic basis for detailed interpretations of Quaternary paleoenvironmental change. The 90??m-thick Quaternary record of the Albemarle Embayment in the mid-Atlantic coastal plain of the USA provides an excellent opportunity to use such an approach in a region where the details of Quaternary environmental change are poorly known. The foraminiferal record in nine cores from the northern Outer Banks, east of Albemarle Sound, North Carolina, indicates the deposition of subhorizontal, mostly open-marine early to late Pleistocene units unconformably upon a basement of late Pliocene reduced-oxygen, fine-grained, shelf-basin deposits. Pollen data record several warm-cool fluctuations within the early to mid-Pleistocene deposits. Diatom data indicate that some fresh and brackish-water units occur within the generally open-marine Pleistocene succession. A channel cut by the paleo-Roanoke River during the last glacial sea-level lowstand occurs in the northern part of the study area. Pollen indicates that the basal fluvial valley fill accumulated in cooler than modern climate conditions in the latest Pleistocene. Overlying silts and muds accumulated under cool climatic, estuarine conditions according to diatom and pollen data. Radiocarbon ages from the estuarine deposits indicate that the bulk of these sediments accumulated during the latest Pleistocene. The estuarine channel-fill deposits are overlain by Holocene open-marine sands deposited as the rising sea transgressed into the estuary approximately 8.5 to 9.0??kyr BP. Within the barrier island drill cores of this study, fully marine sedimentation occurred throughout the Holocene. However, immediately west of the present barrier island, mid- to late Holocene estuarine deposits underlie the modern Albemarle Sound. The islands that currently form a continuous barrier across the mouth of Albemarle Sound have a complex history of Holocene construction and destruction and large portions of them may be less than 3??kyr old. The barrier island sands overlie open-marine sands of Colington Shoal in the north and to the south overlie fluvial and marine sand filling paleo-Roanoke tributary valleys. The Pleistocene sediments underlying the northern Outer Banks study area are mainly of open inner to mid-shelf origin. If, as is likely, sea level continues to rise, a return to such environmental conditions is likely in the near future. ?? 2008 Elsevier B.V.

Advancing global marine biogeography research with open-source GIS software and cloud-computing

USGS Publications Warehouse

Fujioka, Ei; Vanden Berghe, Edward; Donnelly, Ben; Castillo, Julio; Cleary, Jesse; Holmes, Chris; McKnight, Sean; Halpin, patrick

2012-01-01

Across many scientific domains, the ability to aggregate disparate datasets enables more meaningful global analyses. Within marine biology, the Census of Marine Life served as the catalyst for such a global data aggregation effort. Under the Census framework, the Ocean Biogeographic Information System was established to coordinate an unprecedented aggregation of global marine biogeography data. The OBIS data system now contains 31.3 million observations, freely accessible through a geospatial portal. The challenges of storing, querying, disseminating, and mapping a global data collection of this complexity and magnitude are significant. In the face of declining performance and expanding feature requests, a redevelopment of the OBIS data system was undertaken. Following an Open Source philosophy, the OBIS technology stack was rebuilt using PostgreSQL, PostGIS, GeoServer and OpenLayers. This approach has markedly improved the performance and online user experience while maintaining a standards-compliant and interoperable framework. Due to the distributed nature of the project and increasing needs for storage, scalability and deployment flexibility, the entire hardware and software stack was built on a Cloud Computing environment. The flexibility of the platform, combined with the power of the application stack, enabled rapid re-development of the OBIS infrastructure, and ensured complete standards-compliance.

Cumulative and Synergistic Effects of Physical, Biological, and Acoustic Signals on Marine Mammal Habitat Use Physical Oceanography Component: Soundscapes Under Sea Ice: Can We Listen for Open Water?

DTIC Science & Technology

2013-09-30

Physical, Biological, and Acoustic Signals on Marine Mammal Habitat Use Physical Oceanography Component: Soundscapes Under Sea Ice: Can we listen for... Soundscapes Under Sea Ice: Can we listen for open water? 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...the source. These different sounds can be described as “ soundscapes ”, and graphically represented by comparing two or more features of the sound

76 FR 14379 - Marine Fisheries Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-16

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA265 Marine... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of open public meeting. SUMMARY: This notice sets...: The meeting is scheduled for March 30, 2011, 2-3:30 p.m., Eastern Daylight Time. ADDRESSES: Conference...

High abundances of oxalic, azelaic, and glyoxylic acids and methylglyoxal in the open ocean with high biological activity: Implication for secondary OA formation from isoprene

NASA Astrophysics Data System (ADS)

Bikkina, Srinivas; Kawamura, Kimitaka; Miyazaki, Yuzo; Fu, Pingqing

2014-05-01

Atmospheric dicarboxylic acids (DCA) are a ubiquitous water-soluble component of secondary organic aerosols (SOA), which can act as cloud condensation nuclei (CCN), affecting the Earth's climate. Despite the high abundances of oxalic acid and related compounds in the marine aerosols, there is no consensus on what controls their distributions over the open ocean. Marine biological productivity could play a role in the production of DCA, but there is no substantial evidence to support this hypothesis. Here we present latitudinal distributions of DCA, oxoacids and α-dicarbonyls in the marine aerosols from the remote Pacific. Their concentrations were found several times higher in more biologically influenced aerosols (MBA) than less biologically influenced aerosols. We propose isoprene and unsaturated fatty acids as sources of DCA as inferred from significantly higher abundances of isoprene-SOA tracers and azelaic acid in MBA. These results have implications toward the reassessment of climate forcing feedbacks of marine-derived SOA.

Integrating paleoecology and genetics of bird populations in two sky island archipelagos

PubMed Central

McCormack, John E; Bowen, Bonnie S; Smith, Thomas B

2008-01-01

Background Genetic tests of paleoecological hypotheses have been rare, partly because recent genetic divergence is difficult to detect and time. According to fossil plant data, continuous woodland in the southwestern USA and northern Mexico became fragmented during the last 10,000 years, as warming caused cool-adapted species to retreat to high elevations. Most genetic studies of resulting 'sky islands' have either failed to detect recent divergence or have found discordant evidence for ancient divergence. We test this paleoecological hypothesis for the region with intraspecific mitochondrial DNA and microsatellite data from sky-island populations of a sedentary bird, the Mexican jay (Aphelocoma ultramarina). We predicted that populations on different sky islands would share common, ancestral alleles that existed during the last glaciation, but that populations on each sky island, owing to their isolation, would contain unique variants of postglacial origin. We also predicted that divergence times estimated from corrected genetic distance and a coalescence model would post-date the last glacial maximum. Results Our results provide multiple independent lines of support for postglacial divergence, with the predicted pattern of shared and unique mitochondrial DNA haplotypes appearing in two independent sky-island archipelagos, and most estimates of divergence time based on corrected genetic distance post-dating the last glacial maximum. Likewise, an isolation model based on multilocus gene coalescence indicated postglacial divergence of five pairs of sky islands. In contrast to their similar recent histories, the two archipelagos had dissimilar historical patterns in that sky islands in Arizona showed evidence for older divergence, suggesting different responses to the last glaciation. Conclusion This study is one of the first to provide explicit support from genetic data for a postglacial divergence scenario predicted by one of the best paleoecological records in the world. Our results demonstrate that sky islands act as generators of genetic diversity at both recent and historical timescales and underscore the importance of thorough sampling and the use of loci with fast mutation rates to studies that test hypotheses concerning recent genetic divergence. PMID:18588695

Project DAFNE - Drilling Active Faults in Northern Europe

NASA Astrophysics Data System (ADS)

Kukkonen, I. T.; Ask, M. S. V.; Olesen, O.

2012-04-01

We are currently developing a new ICDP project 'Drillling Active Faults in Northern Europe' (DAFNE) which aims at investigating, via scientific drilling, the tectonic and structural characteristics of postglacial (PG) faults in northern Fennoscandia, including their hydrogeology and associated deep biosphere [1, 2]. During the last stages of the Weichselian glaciation (ca. 9,000 - 15,000 years B.P.), reduced ice load and glacially affected stress field resulted in active faulting in Fennoscandia with fault scarps up to 160 km long and 30 m high. These postglacial (PG) faults are usually SE dipping, SW-NE oriented thrusts, and represent reactivated, pre-existing crustal discontinuities. Postglacial faulting indicates that the glacio-isostatic compensation is not only a gradual viscoelastic phenomenon, but includes also unexpected violent earthquakes, suggestively larger than other known earthquakes in stable continental regions. The research is anticipated to advance science in neotectonics, hydrogeology and deep biosphere studies, and provide important information for nuclear waste and CO2 disposal, petroleum exploration on the Norwegian continental shelf and studies of mineral resources in PG fault areas. We expect that multidisciplinary research applying shallow and deep drilling of postglacial faults would provide significant scientific results through generating new data and models, namely: (1) Understanding PG fault genesis and controls of their locations; (2) Deep structure and depth extent of PG faults; (3) Textural, mineralogical and physical alteration of rocks in the PG faults; (4) State of stress and estimates of paleostress of PG faults; (5) Hydrogeology, hydrochemistry and hydraulic properties of PG faults; (6) Dating of tectonic reactivation(s) and temporal evolution of tectonic systems hosting PG faults; (7) Existence/non-existence of deep biosphere in PG faults; (8) Data useful for planning radioactive waste disposal in crystalline bedrock; (9) Data on rock stress changes in the periphery of the inland ice; (10) Stress pattern along the Norwegian continental margin in relation to the bending spreading ridge and Plio-Pleistocene erosion, uplift and sedimentation with implications for fluid migration and sealing properties of petroleum reservoirs. (11) Data useful in predicting future seismic activity in areas of current deglaciation due to ongoing climatic warming.

Holocene vegetation, environment and anthropogenic influence in the Fuzhou Basin, southeast China

NASA Astrophysics Data System (ADS)

Yue, Yuanfu; Zheng, Zhuo; Rolett, Barry V.; Ma, Ting; Chen, Cong; Huang, Kangyou; Lin, Gongwu; Zhu, Guangqi; Cheddadi, Rachid

2015-03-01

A ∼40 m sediment core (FZ4) was collected from the Fuzhou Basin, near the lower reaches of the Min River, in Fujian Province on the southeast coast of China. The sediment and pollen record contributes to our understanding of Holocene paleogeography, including local changes in vegetation and climate in the context of Neolithic cultural developments. The sediment record reveals a fluvial environment in the Fuzhou Basin during the late Pleistocene, and it demonstrates that a change from fluvial to estuarine conditions at ∼9000 cal yr BP resulted from postglacial sea level rise. Evidence of abundant marine diatoms and tidal flat laminations observed in the FZ4 sediments, implies that the Fuzhou Basin was under marine influence between ∼9000 and ∼2000 cal yr BP. After 2000 cal yr BP, a rapid retreat in coastline associated with fluvial aggradation and coastal progradation produced more shallow water for wetlands and initiated formation of the floodplain landscape. The pollen record reveals the presence of a dense subtropical forest between ca. 9000 and 7000 cal yr BP, representing the Holocene thermal maximum, which is linked with rising sea level and marine transgression in the Fuzhou Basin. Between ca. 5500 and 2000 cal yr BP, the thermophilous forest dominated by Castanopsis retreated and coniferous forest expanded, reflecting moderate climatic cooling during this period. Timing of the high frequencies for Pinus and ferns correspond with the mid-late Holocene cooling trend recorded in local mountain peatland and coastal regions of the lower Yangtze and Hanjiang deltas. Anthropogenically induced land cover change was negligible prior to the Tanshishan cultural period, which marks the beginning of Neolithic era sedentary village life on the Fujian coast around 5500 BP. The pollen transition at ca. 3000-1500 cal yr BP, distinguished by rising frequencies of Poaceae and taxa (including Cyperaceae and Artemisia) closely associated with agricultural land cover, indicates exploitation of newly formed lowlands in the emerging Min River floodplain. The historic era intensification of rice agriculture is reflected in this trend of rising frequencies of Poaceae. After ca. 2000 cal yr BP, we observe the onset of a marine regression followed by evidence for an intensely human-impacted environment characterized by sharp rises in pioneer plants such as Poaceae and Dicranopteris. This transition coincides with a rapid retreat of coastline and emergence of the Fuzhou Basin floodplain.

Late-Quaternary glaciation and postglacial emergence, southern Eureka Sound, high-Arctic Canada

NASA Astrophysics Data System (ADS)

O Cofaigh, Colm Seamus

Eureka Sound is the inter-island channel separating Ellesmere and Axel Heiberg islands, High Arctic Canada. This thesis reconstructs the glacial and sea level history of southern Eureka Sound through surficial geological mapping, studies of glacial sedimentology and geomorphology, surveying of raised marine shorelines, radiocarbon dating of marine shells and driftwood and surface exposure dating of erratics and bedrock. Granite dispersal trains, shelly till and ice-moulded bedrock record westerly-flow of warm-based, regional ice into Eureka Sound from a source on southeastern Ellesmere Island during the late Wisconsinan. Regional ice was coalescent with local ice domes over Raanes and northern Svendsen peninsulas. Marine limit (dating <=9.2 ka BP; <=9.9 ka cal BP) is inset into the dispersal trains and records early Holocene deglaciation of regional ice. Collectively these data indicate an extensive ice-cover in southern Eureka Sound during the Last Glacial Maximum. Ice-divides were located along the highlands of central Ellesmere and Axel Heiberg islands, from which ice converged on Eureka Sound, and subsequently flowed north and south along the channel. Deglaciation was characterised by a two-step retreat pattern, likely triggered by eustatic sea level rise and abrupt early Holocene warming. Initial break-up and radial retreat of ice in Eureka Sound and the larger fiords, preceded terrestrial stabilisation along coastlines and inner fiords. Location of deglacial depocentres was predominantly controlled by fiord bathymetry. Regionally, two-step deglaciation is reflected by prominent contrasts in glacial geomorphology between the inner and outer parts of many fiords. Glacial sedimentological and geomorphological evidence indicates spatial variation in basal thermal regime between retreating trunk glaciers. Holocene emergence of up to 150 m asl along southern Eureka Sound is recorded by raised marine deltas, beaches and washing limits. Emergence curves exhibit marked contrasts in the form and rate of initial unloading. Isobases drawn on the 8.5 ka shoreline for greater Eureka Sound demonstrate that a cell of highest emergence extends along the length of the channel, and closes in the vicinity of the entrance to Norwegian Bay. The isobase pattern indicates a distinct loading centre over the sound, and in conjunction with glacial geological evidence, suggests that the thickest late Wisconsinan ice lay over the channel.

Displaced phylogeographic signals from Gyrodactylus arcuatus, a parasite of the three-spined stickleback Gasterosteus aculeatus, suggest freshwater glacial refugia in Europe

USGS Publications Warehouse

Lumme, Jaakko; Mäkinen, Hannu; Ermolenko, Alexey V.; Gregg, Jacob L.; Ziętara, Marek S.

2016-01-01

We examined the global mitochondrial phylogeography of Gyrodactylus arcuatus, a flatworm ectoparasite of three-spined stickleback Gasterosteus aculeatus. In accordance with the suggested high divergence rate of 13%/million years, the genetic variation of the parasite was high: haplotype diversity h = 0.985 and nucleotide diversity π = 0.0161. The differentiation among the parasite populations was substantial (Φst = 0.759), with two main allopatric clades (here termed Euro and North) accounting for 54% of the total genetic variation. The diversity center of the Euro clade was in the Baltic Sea, while the North clade was spread across the Barents and White Seas. A single haplotype within the North clade was found in the western and eastern Pacific Ocean. Divergence of main clades was estimated to be circa 200 thousand years ago. Each main clade was further divided into six distinct subclades, estimated to have diverged in isolation since 135 thousand years ago. This second division corresponds approximately to the Eemian interglacial predating the last glacial maximum. A demographic expansion of the subclades is associated with colonisation of northern Europe since the last glacial maximum, circa 15–40 thousand years ago. The parasite phylogeny is most likely explained by sequential isolated bottlenecks and expansions in numerous allopatric refugia. The postglacial intermingling and high variation in the marine parasite populations, separately in the Baltic and Barents Seas, suggest low competition of divergent parasite matrilines, coupled with a large population size and high rate of dispersal of hosts. The genetic contribution of the assumed refugial fish populations maintaining the parasite during the last glacial maximum was not detected among the marine sticklebacks, which perhaps were infected after range expansion.

Displaced phylogeographic signals from Gyrodactylus arcuatus, a parasite of the three-spined stickleback Gasterosteus aculeatus, suggest freshwater glacial refugia in Europe.

PubMed

Lumme, Jaakko; Mäkinen, Hannu; Ermolenko, Alexey V; Gregg, Jacob L; Ziętara, Marek S

2016-08-01

We examined the global mitochondrial phylogeography of Gyrodactylus arcuatus, a flatworm ectoparasite of three-spined stickleback Gasterosteus aculeatus. In accordance with the suggested high divergence rate of 13%/million years, the genetic variation of the parasite was high: haplotype diversity h=0.985 and nucleotide diversity π=0.0161. The differentiation among the parasite populations was substantial (Φst=0.759), with two main allopatric clades (here termed Euro and North) accounting for 54% of the total genetic variation. The diversity center of the Euro clade was in the Baltic Sea, while the North clade was spread across the Barents and White Seas. A single haplotype within the North clade was found in the western and eastern Pacific Ocean. Divergence of main clades was estimated to be circa 200 thousand years ago. Each main clade was further divided into six distinct subclades, estimated to have diverged in isolation since 135 thousand years ago. This second division corresponds approximately to the Eemian interglacial predating the last glacial maximum. A demographic expansion of the subclades is associated with colonisation of northern Europe since the last glacial maximum, circa 15-40 thousand years ago. The parasite phylogeny is most likely explained by sequential isolated bottlenecks and expansions in numerous allopatric refugia. The postglacial intermingling and high variation in the marine parasite populations, separately in the Baltic and Barents Seas, suggest low competition of divergent parasite matrilines, coupled with a large population size and high rate of dispersal of hosts. The genetic contribution of the assumed refugial fish populations maintaining the parasite during the last glacial maximum was not detected among the marine sticklebacks, which perhaps were infected after range expansion. Copyright © 2016 Australian Society for Parasitology. All rights reserved.

New constraints on the spatial distribution and morphology of the Halimeda bioherms of the Great Barrier Reef, Australia

NASA Astrophysics Data System (ADS)

McNeil, Mardi A.; Webster, Jody M.; Beaman, Robin J.; Graham, Trevor L.

2016-12-01

Halimeda bioherms occur as extensive geological structures on the northern Great Barrier Reef (GBR), Australia. We present the most complete, high-resolution spatial mapping of the northern GBR Halimeda bioherms, based on new airborne lidar and multibeam echosounder bathymetry data. Our analysis reveals that bioherm morphology does not conform to the previous model of parallel ridges and troughs, but is far more complex than previously thought. We define and describe three morphological sub-types: reticulate, annulate, and undulate, which are distributed in a cross-shelf pattern of reduced complexity from east to west. The northern GBR bioherms cover an area of 6095 km2, three times larger than the original estimate, exceeding the area and volume of calcium carbonate in the adjacent modern shelf-edge barrier reefs. We have mapped a 1740 km2 bioherm complex north of Raine Island in the Cape York region not previously recorded, extending the northern limit by more than 1° of latitude. Bioherm formation and distribution are controlled by a complex interaction of outer-shelf geometry, regional and local currents, coupled with the morphology and depth of continental slope submarine canyons determining the delivery of cool, nutrient-rich water upwelling through inter-reef passages. Distribution and mapping of Halimeda bioherms in relation to Great Barrier Reef Marine Park Authority bioregion classifications and management zones are inconsistent and currently poorly defined due to a lack of high-resolution data not available until now. These new estimates of bioherm spatial distribution and morphology have implications for understanding the role these geological features play as structurally complex and productive inter-reef habitats, and as calcium carbonate sinks which record a complete history of the Holocene post-glacial marine transgression in the northern GBR.

Are greenhouse gas emissions from international shipping a type of marine pollution?

PubMed

Shi, Yubing

2016-12-15

Whether greenhouse gas emissions from international shipping are a type of marine pollution is a controversial issue and is currently open to debate. This article examines the current treaty definitions of marine pollution, and applies them to greenhouse gas emissions from ships. Based on the legal analysis of treaty definitions and relevant international and national regulation on this issue, this article asserts that greenhouse gas emissions from international shipping are a type of 'conditional' marine pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

New cetacean ΔR values for Arctic North America and their implications for marine-mammal-based palaeoenvironmental reconstructions

NASA Astrophysics Data System (ADS)

Furze, Mark F. A.; Pieńkowski, Anna J.; Coulthard, Roy D.

2014-05-01

Radiocarbon-dated marine mammal remains from emergent Arctic coastlines have frequently been used to reconstruct Holocene sea-ice histories. The use of such reconstructions has hitherto been complicated by uncertain marine reservoir corrections precluding meaningful intercomparisons with data reported in calibrated or sidereal years. Based on an exhaustive compilation of previously published marine mammal radiocarbon dates (both live-harvested materials and subfossils) from the Canadian Arctic Archipelago (CAA), new, statistically-derived δ13C and ΔR values are provided. Average δ13C values are: -16.1 ± 1.1‰ (bone collagen; n = 193) for bowhead (Balaena mysticetus); -14.4 ± 0.5‰ (n = 44; dentine) for beluga (Delphinapterus leucas); -14.8 ± 1.9‰ (teeth and tusks; n = 18) and -18.0 ± 4.7‰ (n = 9; bone collagen) for walrus (Odobenus rosmarus). ΔR values are 170 ± 95 14C years for bowhead (n = 23) and 240 ± 60 14C years for beluga (n = 12). Scarce data preclude calculation of meaningful, statistically robust walrus ΔR. Using the new ΔR values, an expanded and revised database of calibrated bowhead dates (651 dates; many used in previous CAA sea-ice reconstructions) shows pronounced late Quaternary spatio-temporal fluctuations in bone abundance. Though broadly resembling earlier bowhead subfossil frequency data, analysis of the new expanded database suggests early- and mid-Holocene increases in whale abundance to be of longer duration and lower amplitude than previously considered. A more even and persistent spread of infrequent low-abundance remains during “whale free” intervals is also seen. The dominance of three eastern regions (Prince Regent Inlet & Gulf of Boothia; Admiralty Inlet; Berlinguet Inlet/Bernier Bay) in the CAA data, collectively contributing up to 88% of all subfossil remains in the mid-Holocene, is notable. An analysis of calibrated regional sea-level index points suggests that severance of the Admiralty Inlet-Gulf of Boothia marine channel due to isostatically-driven regression may have played a significant role in enhanced whale mortality during this interval. Comparisons between the newly calibrated bowhead data and other regional sea-ice proxy data further highlight spatial and temporal discrepancies, potentially due to regional asynchronicities and variable sensitivities in proxy response to climate and oceanographic forcing. However, the limited number of deglacial-postglacial marine records continues to hamper extensive intercomparisons between marine mammal and other proxy datasets. Nevertheless, an examination of assumptions inherent in linking bowhead subfossil frequencies, population densities, and sea-ice thickness and distribution, shows that such relationships are highly complex. Factors such as broad sea-ice preferences, variable mortality rates and causes, long distance carcass transport, variable coastline and basin/channel geometries, and changing emergence rates all complicate the correlation of whale bone abundance to sea-ice histories.

Naval open systems architecture

NASA Astrophysics Data System (ADS)

Guertin, Nick; Womble, Brian; Haskell, Virginia

2013-05-01

For the past 8 years, the Navy has been working on transforming the acquisition practices of the Navy and Marine Corps toward Open Systems Architectures to open up our business, gain competitive advantage, improve warfighter performance, speed innovation to the fleet and deliver superior capability to the warfighter within a shrinking budget1. Why should Industry care? They should care because we in Government want the best Industry has to offer. Industry is in the business of pushing technology to greater and greater capabilities through innovation. Examples of innovations are on full display at this conference, such as exploring the impact of difficult environmental conditions on technical performance. Industry is creating the tools which will continue to give the Navy and Marine Corps important tactical advantages over our adversaries.

78 FR 35042 - Merchant Marine Personnel Advisory Committee: Intercessional Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-11

... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2013-0407] Merchant Marine Personnel... Labor Organization's Maritime Labour Convention, 2006.'' This meeting will be open to the public. DATES... words ``Department of Homeland Security'' and the docket number for this action. Comments received will...

77 FR 1944 - Merchant Marine Personnel Advisory Committee: Intercessional Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-12

... Performance Measures (Assessment Criteria).'' This meeting will be open to the public. DATES: A MERPAC working..., working group meeting is as follows: (1) Review existing performance measures and develop new performance... Committee Working Group Meeting. SUMMARY: The Merchant Marine Personnel Advisory Committee (MERPAC) will...

77 FR 11142 - Merchant Marine Personnel Advisory Committee: Intercessional Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... Committee working group meeting. SUMMARY: The Merchant Marine Personnel Advisory Committee (MERPAC) will conduct an intercessional meeting so that a working group may discuss Task Statement 76, entitled ``Review of Performance Measures (Assessment Criteria).'' This meeting will be open to the public. DATES: A...

Life in the "plastisphere": microbial communities on plastic marine debris.

PubMed

Zettler, Erik R; Mincer, Tracy J; Amaral-Zettler, Linda A

2013-07-02

Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.

Phytoplankton-Environmental Interactions in Reservoirs. Volume II. Discussion of Workshop Papers and Open Literature.

DTIC Science & Technology

1981-09-01

Springfield, Va. 22151. II. KEY WORDS (Continue on revere side it necessary and Id lltv by block number) Environmental effects Marine plants Phytoplankton...NITROGEN AND PHOSPHORUS ........ ................. 73 IV-4 HALF-SATURATION CONSTANTS FOR N, P, AND Si UPTAKE (PM) REPORTED FOR MARINE AND FRESHWATER...PLANKTON ALGAE . . . . 74 IV-5 MINIMUM CELL NUTRIENT QUOTAS (OIMOLES CELL - ) OF PM Si, AND N FOR SOME MARINE AND FRESHWATER PHYTOPLANKTON . . . 75 IV

Storm-induced redistribution of deepwater sediments in Lake Ontario

USGS Publications Warehouse

Halfman, J.D.; Dittman, D.E.; Owens, R.W.; Etherington, M.D.

2006-01-01

High-resolution seismic reflection profiles, side-scan sonar profiles, and surface sediment analyses for grain size (% sand, silt & clay), total organic carbon content, and carbonate content along shore-perpendicular transects offshore of Olcott and Rochester in Lake Ontario were utilized to investigate cm-thick sands or absence of deep-water postglacial sediments in water depths of 130 to 165 m. These deepwater sands were observed as each transect approached and occupied the "sills," identified by earlier researchers, between the three deepest basins of the lake. The results reveal thin (0 to 5-cm) postglacial sediments, lake floor lineations, and sand-rich, organic, and carbonate poor sediments at the deepwater sites (> 130 m) along both transects at depths significantly below wave base, epilimnetic currents, and internal wave activity. These sediments are anomalous compared to shallower sediments observed in this study and deeper sediments reported by earlier research, and are interpreted to indicate winnowing and resuspension of the postglacial muds. We hypothesize that the mid-lake confluence of the two-gyre surface current system set up by strong storm events extends down to the lake floor when the lake is isothermal, and resuspends and winnows lake floor sediment at these locations. Furthermore, we believe that sedimentation is more likely to be influenced by bottom currents at these at these sites than in the deeper basins because these sites are located on bathymetric highs between deeper depositional basins of the lake, and the bathymetric constriction may intensify any bottom current activity at these sites.

Long-term archives reveal shifting extinction selectivity in China's postglacial mammal fauna

PubMed Central

Crees, Jennifer J.; Li, Zhipeng; Bielby, Jon; Yuan, Jing

2017-01-01

Ecosystems have been modified by human activities for millennia, and insights about ecology and extinction risk based only on recent data are likely to be both incomplete and biased. We synthesize multiple long-term archives (over 250 archaeological and palaeontological sites dating from the early Holocene to the Ming Dynasty and over 4400 historical records) to reconstruct the spatio-temporal dynamics of Holocene–modern range change across China, a megadiverse country experiencing extensive current-day biodiversity loss, for 34 mammal species over three successive postglacial time intervals. Our combined zooarchaeological, palaeontological, historical and current-day datasets reveal that both phylogenetic and spatial patterns of extinction selectivity have varied through time in China, probably in response both to cumulative anthropogenic impacts (an ‘extinction filter’ associated with vulnerable species and accessible landscapes being affected earlier by human activities) and also to quantitative and qualitative changes in regional pressures. China has experienced few postglacial global species-level mammal extinctions, and most species retain over 50% of their maximum estimated Holocene range despite millennia of increasing regional human pressures, suggesting that the potential still exists for successful species conservation and ecosystem restoration. Data from long-term archives also demonstrate that herbivores have experienced more historical extinctions in China, and carnivores have until recently displayed greater resilience. Accurate assessment of patterns of biodiversity loss and the likely predictive power of current-day correlates of faunal vulnerability and resilience is dependent upon novel perspectives provided by long-term archives. PMID:29167363

Unique mitochondrial DNA lineages in Irish stickleback populations: cryptic refugium or rapid recolonization?

PubMed

Ravinet, Mark; Harrod, Chris; Eizaguirre, Christophe; Prodöhl, Paulo A

2014-06-01

Repeated recolonization of freshwater environments following Pleistocene glaciations has played a major role in the evolution and adaptation of anadromous taxa. Located at the western fringe of Europe, Ireland and Britain were likely recolonized rapidly by anadromous fishes from the North Atlantic following the last glacial maximum (LGM). While the presence of unique mitochondrial haplotypes in Ireland suggests that a cryptic northern refugium may have played a role in recolonization, no explicit test of this hypothesis has been conducted. The three-spined stickleback is native and ubiquitous to aquatic ecosystems throughout Ireland, making it an excellent model species with which to examine the biogeographical history of anadromous fishes in the region. We used mitochondrial and microsatellite markers to examine the presence of divergent evolutionary lineages and to assess broad-scale patterns of geographical clustering among postglacially isolated populations. Our results confirm that Ireland is a region of secondary contact for divergent mitochondrial lineages and that endemic haplotypes occur in populations in Central and Southern Ireland. To test whether a putative Irish lineage arose from a cryptic Irish refugium, we used approximate Bayesian computation (ABC). However, we found no support for this hypothesis. Instead, the Irish lineage likely diverged from the European lineage as a result of postglacial isolation of freshwater populations by rising sea levels. These findings emphasize the need to rigorously test biogeographical hypothesis and contribute further evidence that postglacial processes may have shaped genetic diversity in temperate fauna.

Unique mitochondrial DNA lineages in Irish stickleback populations: cryptic refugium or rapid recolonization?

PubMed Central

Ravinet, Mark; Harrod, Chris; Eizaguirre, Christophe; Prodöhl, Paulo A

2014-01-01

Repeated recolonization of freshwater environments following Pleistocene glaciations has played a major role in the evolution and adaptation of anadromous taxa. Located at the western fringe of Europe, Ireland and Britain were likely recolonized rapidly by anadromous fishes from the North Atlantic following the last glacial maximum (LGM). While the presence of unique mitochondrial haplotypes in Ireland suggests that a cryptic northern refugium may have played a role in recolonization, no explicit test of this hypothesis has been conducted. The three-spined stickleback is native and ubiquitous to aquatic ecosystems throughout Ireland, making it an excellent model species with which to examine the biogeographical history of anadromous fishes in the region. We used mitochondrial and microsatellite markers to examine the presence of divergent evolutionary lineages and to assess broad-scale patterns of geographical clustering among postglacially isolated populations. Our results confirm that Ireland is a region of secondary contact for divergent mitochondrial lineages and that endemic haplotypes occur in populations in Central and Southern Ireland. To test whether a putative Irish lineage arose from a cryptic Irish refugium, we used approximate Bayesian computation (ABC). However, we found no support for this hypothesis. Instead, the Irish lineage likely diverged from the European lineage as a result of postglacial isolation of freshwater populations by rising sea levels. These findings emphasize the need to rigorously test biogeographical hypothesis and contribute further evidence that postglacial processes may have shaped genetic diversity in temperate fauna. PMID:25360281

Ice-sheet-driven methane storage and release in the Arctic

PubMed Central

Portnov, Alexey; Vadakkepuliyambatta, Sunil; Mienert, Jürgen; Hubbard, Alun

2016-01-01

It is established that late-twentieth and twenty-first century ocean warming has forced dissociation of gas hydrates with concomitant seabed methane release. However, recent dating of methane expulsion sites suggests that gas release has been ongoing over many millennia. Here we synthesize observations of ∼1,900 fluid escape features—pockmarks and active gas flares—across a previously glaciated Arctic margin with ice-sheet thermomechanical and gas hydrate stability zone modelling. Our results indicate that even under conservative estimates of ice thickness with temperate subglacial conditions, a 500-m thick gas hydrate stability zone—which could serve as a methane sink—existed beneath the ice sheet. Moreover, we reveal that in water depths 150–520 m methane release also persisted through a 20-km-wide window between the subsea and subglacial gas hydrate stability zone. This window expanded in response to post-glacial climate warming and deglaciation thereby opening the Arctic shelf for methane release. PMID:26739497

75 FR 6178 - Caribbean Fishery Management Council; Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-08

.... The meeting is open to the public, and will be conducted in English. DATES: The SSC meeting will be... -Puerto Rico's Data Collection - DNER -USVI Data Collection - DPNR -Discussion Proposed Revision of Marine... -Presentation by Todd Gedamke -Discussion Information on Density Ratio Control Rules Using Marine Reserves...

Report on the 5th International Bio-logging Symposium

DTIC Science & Technology

2014-09-30

LONG-TERM GOALS Bio-logging originated in the marine (polar) realm, which explains why marine mammals remain today the main biological models in...Wikelski as the convenor. The Proceedings of BLS5 will be published in two open-access BioMed Central (BMC) journals: Animal Biotelemetry (http

Marine Resources

NASA Technical Reports Server (NTRS)

Sherman, J. W., III

1975-01-01

The papers presented in the marine session may be broadly grouped into several classes: microwave region instruments compared to infrared and visible region sensors, satellite techniques compared to aircraft techniques, open ocean applications compared to coastal region applications, and basic research and understanding of ocean phenomena compared to research techniques that offer immediate applications.

Hydrodynamics and Marine Optics during Cold Fronts at Santa Rosa Island, Florida

DTIC Science & Technology

2012-09-01

Journal of Coastal Research 28 S 1073-1087 Coconut Creek, Florida September 2012 Hydrodynamics and Marine Optics during Cold Fronts at Santa Rosa...Research, 28ɝ), 1073-1087. Coconut Creek (Florida), ISSN 0749-0208. Observations of optical and hydrodynamic processes were made on the open beach on

Investigating A Unique Open Ocean Geochemical Record Of the End Triassic Mass Extinction from Panthalassa

NASA Astrophysics Data System (ADS)

Marroquín, S. M.; Gill, B. C.; Them, T. R., II; Trabucho-Alexandre, J. P.; Aberhan, M.; Owens, J. D.; Gröcke, D. R.; Caruthers, A. H.

2017-12-01

The end-Triassic mass extinction ( 201 Ma) was a time of intense disturbance for marine communities. This event is estimated to have produced as much as a loss of 80% of known marine species. The protracted interval of elevated extinction rates is also characterized by a major carbon cycle perturbation and potentially widespread oxygen deficiency within the oceans. While the causes of extinction and environmental feedbacks are still debated it is hypothesized to have been triggered by massive volcanism associated with the Central Atlantic Magmatic Province flood basalts. However, our understanding of the Latest Triassic-Earliest Jurassic interval is limited due to the lack of well-preserved stratigraphic successions outside of the Tethys Ocean (present day Europe), with most of the records from epicontinental and marginal marine settings. To expand our understanding of this critical interval, our study seeks to document biological and environmental changes elsewhere. Specifically, we document and reconstruct these changes in the equatorial Panthalassan Ocean. We will present new data from a sedimentary succession preserved in the Wrangell Mountains of Alaska that spans the Late Triassic through Early Jurassic. The sedimentary succession represents a mixed carbonate-siliciclastic ramp that was deposited at tropical latitudes, adjacent to an island arc in the open Panthalassan Ocean. This succession affords a unique view of open marine conditions, and also holds the potential for excellent temporal control as it contains abundant ash layers throughout, as well as, key ammonite and bivalve fossil occurrences that provide biostratigraphic control. We will present an integrated geochemical and paleontological record from this site using several geochemical proxies (carbon, δ13Ccarb and % total organic carbon, sulfur, δ34S, as well as pyrite contents and iron speciation) along with ammonite and bivalve occurrence data to reconstruct the record of environmental and biological change within the open Panthalassan Ocean, and relate these data to existing marine records of the end-Triassic extinction.

78 FR 48314 - Drawbridge Operation Regulation; Milford Haven Inlet, Hudgins, VA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-08

... regular operating schedule where the bridge opens on signal, the bridge opens up to ten times every day... Broadcast Notices to Mariners at least seven days in advance of the changes in operating schedule so that...

ostglacial rebound from VLBI Geodesy: On Establishing Vertical Reference

NASA Technical Reports Server (NTRS)

Argus, Donald .

1996-01-01

I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan, 1995] and predictions from postglacial rebound predictions [Peltier, 1995].

Studies toward brevisulcenal F via convergent strategies for marine ladder polyether synthesis.

PubMed

Katcher, Matthew; Jamison, Timothy F

2018-03-15

Shortly after the initial isolation of marine ladder polyether natural products, biomimetic epoxide-opening cascade reactions were proposed as an efficient strategy for the synthesis of these compounds. However, difficulties in assembling the cascade precursors have limited the realization of these cascades. In this report, we describe strategies that provide convergent access to cascade precursors via regioselective allylation and efficient fragment coupling. We then investigate epoxide-opening cascades promoted by strong bases for the formation of fused tetrahydropyrans. These strategies are evaluated in the context of the synthesis of rings CDEFG of brevisulcenal F.

Floating cultivation of marine cyanobacteria using coal fly ash.

PubMed

Matsumoto, M; Yoshida, E; Takeyama, H; Matsunaga, T

2000-01-01

The aim of this study was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. We have investigated the viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine micro-algae. The marine cyanobacterium Synechococcus sp. NKBG 040607 was found to adhere to floating CFA blocks in liquid culture medium. Maximum density of attached cells of 2.0 x 10(8) cells/cm2 was achieved using seawater. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.

General view, marine aviation hangars, looking northwest. Oral history has ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view, marine aviation hangars, looking northwest. Oral history has suggested that the north unit of the two surviving structures (in the background with the gable roof) was used as a repair shed by what is now the Philadelphia International Airport when it opened in 1925, and the south (doubled) unit was constructed as part of the 1926 Sesqui-Centennial Exposition. - Lazaretto Quarantine Station, Marine Aviation Hangars, Wanamaker Avenue and East Second Street, Essington, Delaware County, PA

Large Recovery of Fish Biomass in a No-Take Marine Reserve

PubMed Central

Aburto-Oropeza, Octavio; Erisman, Brad; Galland, Grantly R.; Mascareñas-Osorio, Ismael; Sala, Enric; Ezcurra, Exequiel

2011-01-01

No-take marine reserves are effective management tools used to restore fish biomass and community structure in areas depleted by overfishing. Cabo Pulmo National Park (CPNP) was created in 1995 and is the only well enforced no-take area in the Gulf of California, Mexico, mostly because of widespread support from the local community. In 1999, four years after the establishment of the reserve, there were no significant differences in fish biomass between CPNP (0.75 t ha−1 on average) and other marine protected areas or open access areas in the Gulf of California. By 2009, total fish biomass at CPNP had increased to 4.24 t ha−1 (absolute biomass increase of 3.49 t ha−1, or 463%), and the biomass of top predators and carnivores increased by 11 and 4 times, respectively. However, fish biomass did not change significantly in other marine protected areas or open access areas over the same time period. The absolute increase in fish biomass at CPNP within a decade is the largest measured in a marine reserve worldwide, and it is likely due to a combination of social (strong community leadership, social cohesion, effective enforcement) and ecological factors. The recovery of fish biomass inside CPNP has resulted in significant economic benefits, indicating that community-managed marine reserves are a viable solution to unsustainable coastal development and fisheries collapse in the Gulf of California and elsewhere. PMID:21858183

Impact of diagenesis on the environmental magnetic record from a Holocene sedimentary sequence from the Chukchi-Alaskan margin, Arctic Ocean

NASA Astrophysics Data System (ADS)

Brachfeld, Stefanie; Barletta, Francesco; St-Onge, Guillaume; Darby, Dennis; Ortiz, Joseph D.

2009-07-01

We present a high-resolution Holocene sedimentary record of environmental variability from the eastern Chukchi Sea. An ice-rafted debris bearing silty-clay marks the deglacial to post-glacial Holocene transition at this site and is dated at 9.7 ka. An interval of oscillating magnetic parameters from 9.5 to 8.7 ka coincides with the Holocene Thermal Maximum in the western Arctic, and is manifested at the study area as pulses of fine-grained magnetite input every 180-230 years, possibly from increased river discharge or stronger currents flowing over the core site. The magnetic mineral assemblage is very uniform over the last 8.2 ka and consists of a mixture of magnetite, titanomagnetite, and a magnetic phase that we tentatively identify as the magnetic iron sulfide greigite. The amount of magnetic iron sulfides increases up through the Holocene, a trend that is controlled by the amount of marine organic matter available to fuel bacterial sulfate reduction. The median destructive field of the Natural Remanent Magnetization (MDF NRM) displays centennial to millennial scale cycles with significant variance at periods of 900-1300 and 1700-2700 years, with intervals of high MDF NRM values coinciding with indicators of greater sea ice cover [McKay, J., de Vernal, A., Hillaire-Marcel, C., Not, C., Polyak, L., Darby, D., 2008. Holocene fluctuations in Arctic sea-ice cover: Dinocyst-based reconstructions for the eastern Chukchi Sea. Can. J. Earth Sci. 45, 1399-1415]. The MDF NRM is controlled by the variable abundance of iron sulfides formed during early diagenesis. We interpret intervals of high MDF NRM values as times of stronger water column stratification, during which the pyritization process was interrupted by the lack of marine organic matter and lack of reactive iron. Intervals of low MDF NRM values, which coincide with indicators of reduced sea ice cover, are interpreted as times of stronger vertical mixing of the water column, which allows fresh marine organic matter and reactive iron to reach the seafloor, driving the pyritization process to completion.

46 CFR 52.20-17 - Opening between boiler and safety valve (modifies PFT-44).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Opening between boiler and safety valve (modifies PFT-44). 52.20-17 Section 52.20-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Firetube Boilers § 52.20-17 Opening between boiler and safety valve...

46 CFR 52.20-17 - Opening between boiler and safety valve (modifies PFT-44).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Opening between boiler and safety valve (modifies PFT-44). 52.20-17 Section 52.20-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Firetube Boilers § 52.20-17 Opening between boiler and safety valve...

46 CFR 52.20-17 - Opening between boiler and safety valve (modifies PFT-44).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Opening between boiler and safety valve (modifies PFT-44). 52.20-17 Section 52.20-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Firetube Boilers § 52.20-17 Opening between boiler and safety valve...

46 CFR 52.20-17 - Opening between boiler and safety valve (modifies PFT-44).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Opening between boiler and safety valve (modifies PFT-44). 52.20-17 Section 52.20-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Firetube Boilers § 52.20-17 Opening between boiler and safety valve...

77 FR 47792 - Drawbridge Operation Regulation; Schuylkill River, Philadelphia, PA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-10

... to have minimal impact on mariners due to no requests requiring openings for the past 13 years and no... requests requiring openings for the past 13 years. Vessels that can safely transit under the bridge (with a... from Conrail 13 years ago and there have been no requests requiring openings. Based on this lack of...

46 CFR 52.20-17 - Opening between boiler and safety valve (modifies PFT-44).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Opening between boiler and safety valve (modifies PFT-44). 52.20-17 Section 52.20-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Firetube Boilers § 52.20-17 Opening between boiler and safety valve...

Postglacial Rebound and Current Ice Loss Estimates from Space Geodesy: The New ICE-6G (VM5a) Global Model

NASA Astrophysics Data System (ADS)

Peltier, W. R.; Argus, D.; Drummond, R.; Moore, A. W.

2012-12-01

We compare, on a global basis, estimates of site velocity against predictions of the newly constructed postglacial rebound model ICE-6G (VM5a). This model is fit to observations of North American postglacial rebound thereby demonstrating that the ice sheet at last glacial maximum must have been, relative to ICE-5G,thinner in southern Manitoba, thinner near Yellowknife (northwest Territories), thicker in eastern and southern Quebec, and thicker along the British Columbia-Alberta border. The GPS based estimates of site velocity that we employ are more accurate than were previously available because they are based on GPS estimates of position as a function of time determined by incorporating satellite phase center variations [Desai et al. 2011]. These GPS estimates are constraining postglacial rebound in North America and Europe more tightly than ever before. In particular, given the high density of GPS sites in North America, and the fact that the velocity of the mass center (CM) of Earth is also more tightly constrained, the new model much more strongly constrains both the lateral extent of the proglacial forebulge and the rate at which this peripheral bulge (that was emplaced peripheral to the late Pleistocence Laurentia ice sheet) is presently collapsing. This fact proves to be important to the more accurate inference of the current rate of ice loss from both Greenland and Alaska based upon the time dependent gravity observations being provided by the GRACE satellite system. In West Antarctica we have also been able to significantly revise the previously prevalent ICE-5G deglaciation history so as to enable its predictions to be optimally consistent with GPS site velocities determined by connecting campaign WAGN measurements to those provided by observations from the permanent ANET sites. Ellsworth Land (south of the Antarctic peninsula), is observed to be rising at 6 ±3 mm/yr according to our latest analyses; the Ellsworth mountains themselves are observed to be rising at 5 ±4 mm/yr; Palmer Land is observed to be rising at 3 ±3 mm/yr. The predictions of the ICE-5G (VM2) model and those of the postglacial rebound component of the model of Simons, Ivins, and James [2010] had predicted uplift to be significantly faster than observed in this region, as previously documented in Argus et al [2011]. From a global perspective the new ICE-6G (VM5a) model is also a further significant improvement on the previous ICE-5G (VM2) model in that the degree two and order one components of its predicted time dependence of geoid height are tightly constrained by the recent inferences of Roy and Peltier [2011] of the post-GRACE-launch values of the speed and direction of true polar wander and the non-tidal acceleration of the lod. .

Postglacial paleoclimates of the Foxe Basin and surrounding regions (Nunavut, Canada): a multiproxy lake sediment archive study

NASA Astrophysics Data System (ADS)

Pienitz, Reinhard; Beaudoin, Anne; Narancic, Biljana; Rolland, Nicolas; Wagner, Anne-Marie; Zimmermann, Claudia

2013-04-01

Climate change reports show that global warming effects, which are amplified at high latitudes, drive unprecedented environmental changes (ACIA 2005; AMAP-SWIPA 2011). However, not all arctic regions yield the same rate of change (Smol et al. 2005). Several paleoclimate studies completed in areas surrounding the southern Foxe Basin, in Nunavik and Labrador suggest that these regions experienced relatively subtle climatic and environmental changes over the recent past (Pienitz et al. 2004) as compared to the drastic changes reported from the Canadian High Arctic. These contrasting scenarios underscore the need to increase our knowledge of past and present environmental conditions across the Arctic in order to refine our capacity to model past, present and future environmental impacts. Unfortunately, instrumental data available for developing regional and global climate models do not adequately capture the natural environmental variability that has affected these regions over the past. In an effort to explore the potential responses of northern freshwater ecosystems and their watersheds to climatic change and to place instrumental records into a longer-term perspective, we use a multi-proxy paleolimnological approach to study the sedimentary records preserved in several lakes distributed across regions bordering the Foxe Basin (65°-70°N; 71°-85°W) in Nunavut. This presentation will showcase the preliminary results obtained through studies of lake sediment records from the Foxe Peninsula, Southampton Island, Melville Peninsula, Steensby Inlet and the Nettilling Lake area (Nunavut, Canada). Combined with sedimentological analyses (X-ray profiles, XRF, CHN, grain size, magnetic susceptibility), changes in the composition of both fossil chironomid and diatom assemblages provide an improved understanding of the temporal and spatial variability and of the timing of past climatic events since the last deglaciation. Our central objective is to generate a network of decadal-millennial scale records of quantitative variations in water quality parameters (e.g., temperature, dissolved organic carbon, alkalinity) to explore fundamental questions concerning postglacial ecosystem succession and water quality trends in northern landscapes. Regional comparisons with ice core data from the Penny Ice Cap and the Greenland Ice Sheet, as well as with paleoceanographic data from surrounding marine environments should also allow us refine regional paleoclimate models.

Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

EPA Science Inventory

Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emis...

77 FR 66856 - Merchant Marine Personnel Advisory Committee: Intercessional Meeting AGENCY: Coast Guard, DHS

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-07

... Committee Working Group Meeting. SUMMARY: A working group of the Merchant Marine Personnel Advisory Committee (MERPAC) will meet to work on Task Statement 77 concerning the development of new performance...-Technical Ratings. This meeting will be open to the public. DATES: A MERPAC working group will meet on...

78 FR 55687 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-11

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of open meeting. SUMMARY: The Board of Visitors of the Marine Corps University will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of professional...

78 FR 3409 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-16

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of Open Meeting. SUMMARY: The Board of Visitors of the Marine Corps University will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of professional...

75 FR 53958 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-02

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of open meeting. SUMMARY: The Board of Visitors of the Marine Corps University (BOV MCU) will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of...

77 FR 12578 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-01

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of open meeting. SUMMARY: The Board of Visitors of the Marine Corps University will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of professional...

76 FR 12716 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-08

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of open meeting. SUMMARY: The Board of Visitors of the Marine Corps University (BOV MCU) will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of...

76 FR 55367 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-07

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of Open Meeting. SUMMARY: The Board of Visitors of the Marine Corps University will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of [[Page 55368...

77 FR 55813 - Meeting of the Board of Visitors of Marine Corps University

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

... University AGENCY: Department of the Navy, DoD. ACTION: Notice of open meeting. SUMMARY: The Board of Visitors of the Marine Corps University will meet to review, develop and provide recommendations on all aspects of the academic and administrative policies of the University; examine all aspects of professional...

The prediction of the hydrodynamic performance of tidal current turbines

NASA Astrophysics Data System (ADS)

Y Xiao, B.; Zhou, L. J.; Xiao, Y. X.; Wang, Z. W.

2013-12-01

Nowadays tidal current energy is considered to be one of the most promising alternative green energy resources and tidal current turbines are used for power generation. Prediction of the open water performance around tidal turbines is important for the reason that it can give some advice on installation and array of tidal current turbines. This paper presents numerical computations of tidal current turbines by using a numerical model which is constructed to simulate an isolated turbine. This paper aims at studying the installation of marine current turbine of which the hydro-environmental impacts influence by means of numerical simulation. Such impacts include free-stream velocity magnitude, seabed and inflow direction of velocity. The results of the open water performance prediction show that the power output and efficiency of marine current turbine varies from different marine environments. The velocity distribution should be clearly and the suitable unit installation depth and direction be clearly chosen, which can ensure the most effective strategy for energy capture before installing the marine current turbine. The findings of this paper are expected to be beneficial in developing tidal current turbines and array in the future.

Genomic variation of the fibropapilloma-associated marine turtle herpes virus across seven geographic areas and three host species

USGS Publications Warehouse

Greenblatt, R.J.; Quackenbush, S.L.; Casey, R.N.; Rovnak, J.; Balazs, G.H.; Work, Thierry M.; Casey, J.W.; Sutton, C.A.

2005-01-01

Fibropapillomatosis (FP) of marine turtles is an emerging neoplastic disease associated with infection by a novel turtle herpesvirus, fibropapilloma-associated turtle herpesvirus (FPTHV). This report presents 23 kb of the genome of an FPTHV infecting a Hawaiian green turtle (Chelonia mydas). By sequence homology, the open reading frames in this contig correspond to herpes simplex virus genes UL23 through UL36. The order, orientation, and homology of these putative genes indicate that FPTHV is a member of the Alphaherpesvirinae. The UL27-, UL30-, and UL34-homologous open reading frames from FPTHVs infecting nine FP-affected marine turtles from seven geographic areas and three turtle species (C. mydas, Caretta caretta, and Lepidochelys olivacea) were compared. A high degree of nucleotide sequence conservation was found among these virus variants. However, geographic variations were also found: the FPTHVs examined here form four groups, corresponding to the Atlantic Ocean, West pacific, mid-Pacific, and east Pacific. Our results indicate that FPTHV was established in marine turtle populations prior to the emergence of FP as it is currently known.

Earthquakes at North Atlantic passive margins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregersen, S.; Basham, P.W.

1989-01-01

The main focus of this volume is the earthquakes that occur at and near the continental margins on both sides of the North Atlantic. The book, which contains the proceedings of the NATO workshop on Causes and Effects of Earthquakes at Passive Margins and in Areas of Postglacial Rebound on Both Sides of the North Atlantic, draws together the fields of geophysics, geology and geodesy to address the stress and strain in the Earth's crust. The resulting earthquakes produced on ancient geological fault zones and the associated seismic hazards these pose to man are also addressed. Postglacial rebound in Northmore » America and Fennoscandia is a minor source of earthquakes today, during the interglacial period, but evidence is presented to suggest that the ice sheets suppressed earthquake strain while they were in place, and released this strain as a pulse of significant earthquakes after the ice melted about 9000 years ago.« less

Seismic imaging of post-glacial sediments - test study before Spitsbergen expedition

NASA Astrophysics Data System (ADS)

Szalas, Joanna; Grzyb, Jaroslaw; Majdanski, Mariusz

2017-04-01

This work presents results of the analysis of reflection seismic data acquired from testing area in central Poland. For this experiment we used total number of 147 vertical component seismic stations (DATA-CUBE and Reftek "Texan") with accelerated weight drop (PEG-40). The profile was 350 metres long. It is a part of pilot study for future research project on Spitsbergen. The purpose of the study is to recognise the characteristics of seismic response of post-glacial sediments in order to design the most adequate survey acquisition parameters and processing sequence for data from Spitsbergen. Multiple tests and comparisons have been performed to obtain the best possible quality of seismic image. In this research we examine the influence of receiver interval size, front mute application and surface wave attenuation attempts. Although seismic imaging is the main technique we are planning to support this analysis with additional data from traveltime tomography, MASW and other a priori information.

The dilemma of gaps in carbonate stratigraphic sequences: A case history from the Jurassic of the Venetian Alps, Italy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zempolich, W.G.

The Lower Ammonitico Rosso (L.A.R.) of the western Venetian Alps is a thin, red nodular limestone that overlies a thick Late Triassic to Middle Jurassic (Aalenian) shallow-water platform sequence. It is thought to represent a Middle Jurassic (Bajocian) drowning event whereby the Trento Platform became a submerged plateau. The L.A.R. is problematic in that it (1) is rich in ammonites and other pelagic fauna; (2) contains stromatolites, oncolites, and shallow-water sedimentary structures; and (3) directly overlies platform sediments that contain complex brecciated fabrics filled by cement and Bajocian-age sediment. These seemingly contradictory features have generated much debate as to themore » sequence stratigraphy of the Trento Platform. New evidence suggests that the L.A.R. was deposited in a shallow-water environment following a period of subaerial exposure. In an east-west transect from the platform edge to platform interior, a clear transition is exhibited from high- and low-energy open-marine facies to restricted lagoonal facies. High-energy open-marine facies include well-sorted skeletal- and peloidal-rich sands possessing low-angle to planar cross stratification and thin, fairly sorted ammonite- and belemnite-rich gravels. Sands include both shallow-water and pelagic fauna; gravels commonly contain ripup clasts from underlying sediments. Low-energy open-marine facies consist of buff colored wackestones and packstones that contain ammonites, belemnites, pelagic bivalves, and peloids. With respect to paleogeography, the abrupt transition from open-marine facies at the platform edge to lagoonal facies in the platform interior indicates that thrombolites, stromatolites, and oncolites accumulated in a shallow restricted environment.« less

Incorporating Conservation Zone Effectiveness for Protecting Biodiversity in Marine Planning

PubMed Central

Makino, Azusa; Klein, Carissa J.; Beger, Maria; Jupiter, Stacy D.; Possingham, Hugh P.

2013-01-01

Establishing different types of conservation zones is becoming commonplace. However, spatial prioritization methods that can accommodate multiple zones are poorly understood in theory and application. It is typically assumed that management regulations across zones have differential levels of effectiveness (“zone effectiveness”) for biodiversity protection, but the influence of zone effectiveness on achieving conservation targets has not yet been explored. Here, we consider the zone effectiveness of three zones: permanent closure, partial protection, and open, for planning for the protection of five different marine habitats in the Vatu-i-Ra Seascape, Fiji. We explore the impact of differential zone effectiveness on the location and costs of conservation priorities. We assume that permanent closure zones are fully effective at protecting all habitats, open zones do not contribute towards the conservation targets and partial protection zones lie between these two extremes. We use four different estimates for zone effectiveness and three different estimates for zone cost of the partial protection zone. To enhance the practical utility of the approach, we also explore how much of each traditional fishing ground can remain open for fishing while still achieving conservation targets. Our results show that all of the high priority areas for permanent closure zones would not be a high priority when the zone effectiveness of the partial protection zone is equal to that of permanent closure zones. When differential zone effectiveness and costs are considered, the resulting marine protected area network consequently increases in size, with more area allocated to permanent closure zones to meet conservation targets. By distributing the loss of fishing opportunity equitably among local communities, we find that 84–88% of each traditional fishing ground can be left open while still meeting conservation targets. Finally, we summarize the steps for developing marine zoning that accounts for zone effectiveness. PMID:24223870

Human pathogens in marine mammal meat – a northern perspective.

PubMed

Tryland, M; Nesbakken, T; Robertson, L; Grahek-Ogden, D; Lunestad, B T

2014-09-01

Only a few countries worldwide hunt seals and whales commercially. In Norway, hooded and harp seals and minke whales are commercially harvested, and coastal seals (harbour and grey seals) are hunted as game. Marine mammal meat is sold to the public and thus included in general microbiological meat control regulations. Slaughtering and dressing of marine mammals are performed in the open air on deck, and many factors on board sealing or whaling vessels may affect meat quality, such as the ice used for cooling whale meat and the seawater used for cleaning, storage of whale meat in the open air until ambient temperature is reached, and the hygienic conditions of equipment, decks, and other surfaces. Based on existing reports, it appears that meat of seal and whale does not usually represent a microbiological hazard to consumers in Norway, because human disease has not been associated with consumption of such foods. However, as hygienic control on marine mammal meat is ad hoc, mainly based on spot-testing, and addresses very few human pathogens, this conclusion may be premature. Additionally, few data from surveys or systematic quality control screenings have been published. This review examines the occurrence of potential human pathogens in marine mammals, as well as critical points for contamination of meat during the slaughter, dressing, cooling, storage and processing of meat. Some zoonotic agents are of particular relevance as foodborne pathogens, such as Trichinella spp., Toxoplasma gondii, Salmonella and Leptospira spp. In addition, Mycoplasma spp. parapoxvirus and Mycobacterium spp. constitute occupational risks during handling of marine mammals and marine mammal products. Adequate training in hygienic procedures is necessary to minimize the risk of contamination on board, and acquiring further data is essential for obtaining a realistic assessment of the microbiological risk to humans from consuming marine mammal meat.

Geophysical observations on northern part of Georges Bank and adjacent basins of Gulf of Maine

USGS Publications Warehouse

Oldale, R.N.; Hathaway, J.C.; Dillon, William P.; Hendricks, J.D.; Robb, James M.

1974-01-01

Continuous-seismic-reflection and magnetic-intensity profiles provide data for inferences about the geology of the northern part of Georges Bank and the basins of the Gulf of Maine adjacent to the bank.Basement is inferred to be mostly sedimentary and volcanic rocks of Paleozoic age that were metamorphosed and intruded locally by felsic and mafic plutons near the end of the Paleozoic Era. During Late Triassic time, large fault basins formed within the Gulf of Maine and probably beneath Georges Bank. The fault basins and a possible major northeast-trending fault zone beneath the northern part of the bank probably formed as a result of the opening Atlantic during the Mesozoic. Nonmarine sediments, associated with mafic flows and intrusive rocks, were deposited in the fault basins as they formed. The upper surface of the Triassic and pre-Triassic rocks that comprise basement is an unconformity that makes up much of the bottom of the Gulf of Maine. Depth to the basement surface beneath the gulf differ greatly because of fluvial erosion in Tertiary time and glacial erosion in Pleistocene time. Beneath the northern part of Georges Bank the basement surface is smoother and slopes southward. Prominent valleys, cut before Late Cretaceous time, are present beneath this part of the bank.Cretaceous, Tertiary, and possibly Jurassic times were characterized by episodes of coastal-plain deposition and fluvial erosion. During this time a very thick wedge of sediment, mostly of Jurassic(?) and Cretaceous ages, was deposited on the shelf. Major periods of erosion took place at the close of the Cretaceous and during the Pliocene. Fluvial erosion during the Pliocene removed much of the coastal-plain sedimentary wedge and formed the Gulf of Maine.Pleistocene glaciers eroded all but a few remnants of the coastal-plain sediments within the gulf and deposited a thick section of drift against the north slope of Georges Bank and a thin veneer of outwash on the bank. Marine sediments were deposited in the basins of the Gulf of Maine during the retreat of the last ice and the postglacial rise in sea level.

Management Plan Report. Unconfined Open-Water Disposal of Dredged Material. Phase 2. (North and South Puget Sound)

DTIC Science & Technology

1989-09-01

depth of 442’ at the center of the disposal zone. The area is subject to weak currents. In general, commercially important marine invertebrate ...Fish and Wildlife Service " Charles Dunn U.S. Fish and Wildlife Service * Rob Jones National Marine Fisheries Service * Dr. Herb Curl National Oceanic...environmental impacts. In the future, for many projects, disposal in deep and relatively deep marine waters is expected to be a preferred option for envirc

Light-stick: A problem of marine pollution in Brazil.

PubMed

Cesar-Ribeiro, Caio; Rosa, Helena Costi; Rocha, Daniele Oliveira; Dos Reis, Camila Galli Baldini; Prado, Tabata Sarti; Muniz, Daniela Hernandes Coimbra; Carrasco, Raquel; Silva, Flávia Milão; Martinelli-Filho, José Eduardo; Palanch-Hans, Maria Fernanda

2017-04-15

Light-sticks are used as bait in surface long-line fishing, to capture swordfish and other large pelagic predators. When discharged in the ocean, it may reach the beaches. The traditional Brazilian community of Costa dos Coqueiros, Bahia, use light-sticks as a medicine for rheumatism, vitiligo and mycoses. It may affect the marine life when its content leak in the open ocean. This work evaluated and identified the acute and chronic toxicity of the light-stick. A high acute toxicity was observed in the mobility/mortality of Artemia sp.; in the fertilization of sea urchin eggs, and a high chronic toxicity in the development of the pluteus larvae of the same sea urchin. The main compounds that probably caused toxicity were the volatiles such as the fluorescent PAH and oxidants such as the hydrogen peroxide. Its disposal in the open ocean is a potential threat for marine life. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mapping the World's Marine Protected and Managed Areas - Promoting Awareness, Compliance, and Enforcement via Open Data and Tools.

NASA Astrophysics Data System (ADS)

Vincent, T.; Zetterlind, V.; Tougher, B.

2016-12-01

Marine Protected and Managed Areas (MPAs) are a cornerstone of coastal and ocean conservation efforts and reflect years of dedicated effort to protect species and habitats through science-based regulation. When they are effective, biomass increases dramatically, and up to 14 fold and play a significant role in conserving biodiversity. Effective MPAs have enforcement. Enforcement cannot occur without awareness of their location among ocean stakeholders and the general public. The Anthropocene Institute, in partnership with the NOAA Marine Protected Area Center, is creating an actively managed, free and open, worldwide database of MPAs, including normalized metadata and regulation summaries, full GIS boundaries, revision history, and public facing interactive web maps. This project employs 2 full-time lawyers that first comb the relevant regulation; 2 full-time geographers and a full-time GIS database/web engineer.

Experimental evidence of pollination in marine flowers by invertebrate fauna

PubMed Central

van Tussenbroek, Brigitta I.; Villamil, Nora; Márquez-Guzmán, Judith; Wong, Ricardo; Monroy-Velázquez, L. Verónica; Solis-Weiss, Vivianne

2016-01-01

Pollen transport by water-flow (hydrophily) is a typical, and almost exclusive, adaptation of plants to life in the marine environment. It is thought that, unlike terrestrial environments, animals are not involved in pollination in the sea. The male flowers of the tropical marine angiosperm Thalassia testudinum open-up and release pollen in mucilage at night when invertebrate fauna is active. Here we present experimental evidence that, in the absence of water-flow, these invertebrates visit the flowers, carry and transfer mucilage mass with embedded pollen from the male flowers to the stigmas of the female flowers. Pollen tubes are formed on the stigmas, indicating that pollination is successful. Thus, T. testudinum has mixed abiotic–biotic pollination. We propose a zoobenthophilous pollination syndrome (pollen transfer in the benthic zone by invertebrate animals) which shares many characteristics with hydrophily, but flowers are expected to open-up during the night. PMID:27680661

Large submarine sand waves and gravel lag substrates on Georges Bank off Atlantic Canada

USGS Publications Warehouse

Todd, B.J.; Valentine, Page C.; Harris, Peter T; Baker, E.K.

2012-01-01

Georges Bank is a large, shallow, continental shelf feature offshore of New England and Atlantic Canada. The bank is mantled with a veneer of glacial debris transported during the late Pleistocene from continental areas lying to the north. These sediments were reworked by marine processes during postglacial sea-level transgression and continue to be modified by the modern oceanic regime. The surficial geology of the Canadian portion of the bank is a widespread gravel lag overlain in places by well sorted sand occurring as bedforms. The most widespread bedforms are large, mobile, asymmetrical sand waves up to 19 m in height formed through sediment transport by strong tidal-driven and possibly storm-driven currents. Well-defined curvilinear bedform crests up to 15 km long form a complex bifurcating pattern having an overall southwest–northeast strike, which is normal to the direction of the major axis of the semidiurnal tidal current ellipse. Minor fields of immobile, symmetrical sand waves are situated in bathymetric lows. Rare mobile, asymmetrical barchan dunes are lying on the gravel lag in areas of low sand supply. On Georges Bank, the management of resources and habitats requires an understanding of the distribution of substrate types, their surface dynamics and susceptibility to movement, and their associated fauna.

Maps and seismic profiles showing geology of the inner continental shelf, Cape Ann, Massachusetts to New Hampshire

USGS Publications Warehouse

Oldale, R.N.; Wommack, L.E.

1987-01-01

Early studies in the western Gulf of Maine have outlined the general geology and geologic history of the region. Seismic-reflection data have defined the major stratigraphic units and unconformities (Oldale and Uchupi, 1970; Ballard and Uchupi, 1972; Oldale and others, 1973). Two long cores provided information on the glacial and postglacial sediments in the deep offshore basins (Tucholke and Hollister, 1973). Generalized bottom-sediment type and distribution were determined by Schlee and others (1973) and by Folger and others (1975). Investigations on land, which have provided information on the late Quaternary history of the offshore area, include descriptions of ice retreat and marine submergence (Bloom, 1963; Smith, 1982; Stone and Peper, 1982; Thompson, 1982). Radiocarbon dates from coastal marsh peats have established the middle to late Holocene sea-level-rise history (McIntire and Morgan, 1964; Keene, 1971). Submarine moraincs that recently were recognized off Cape Ann provide additional information on the nature and chronology of ice retreat (Oldale, 1985a). A submerged delta of the Merrimack River and a submerged barrier spit have been used to establish an early IIolocene lowstand of 588 level of about 50 meters (m) below present sea level (Oldale and others, 1983; Oldale, 1985b).

Demographic response of cutlassfish (Trichiurus japonicus and T. nanhaiensis) to fluctuating palaeo-climate and regional oceanographic conditions in the China seas.

PubMed

He, Lijun; Zhang, Aibing; Weese, David; Li, Shengfa; Li, Jiansheng; Zhang, Jing

2014-09-16

Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70-140 kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas.

Demographic response of cutlassfish (Trichiurus japonicus and T. nanhaiensis) to fluctuating palaeo-climate and regional oceanographic conditions in the China seas

PubMed Central

He, Lijun; Zhang, Aibing; Weese, David; Li, Shengfa; Li, Jiansheng; Zhang, Jing

2014-01-01

Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70–140 kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas. PMID:25223336

Geomorphological aspects of road construction in a cold environment, Finland

NASA Astrophysics Data System (ADS)

Seppälä, Matti

1999-12-01

Traditionally, road alignments followed easy landscapes and suitable landforms. When traffic and the size and weight of vehicles increased and higher speeds were used, straighter roads were required; the easygoing relief could not always be used, and problems arose. Road contractors could save money in building and maintenance costs by considering the geomorphic facts. The examples from Finland document why road construction is very expensive in the conditions generated by severe winters. In Finland, more paved roads cross the Arctic Circle than in the whole of North America. This paper gives examples of geomorphic elements affecting road construction in a cold environment: eskers, drumlins, plains of late and postglacial glaciolacustrine and marine sediments, mires, steep rock cliffs, river channels and ice-dams, fluvial erosion, and palsas. Solutions to these problems include removal of frost sensible materials and replacement by more favorable sediments. Road surfaces, kept snow-free in the wintertime, are subjected to deep freezing. The maintenance of roads can be supported with some solutions that affect snowdrift and icing problems, avoidance of geomorphic factors that cause problems, and by using natural processes to help people. Some examples of how road construction affects geomorphic processes and vice versa are provided. For example, bridges block moving river ice, and on special occasions, road banks cause icing.

Vegetation responses to interglacial warming in the Arctic, examples from Lake El'gygytgyn, northeast Siberia

NASA Astrophysics Data System (ADS)

Lozhkin, A. V.; Anderson, P. M.

2013-01-01

Palynological data from Lake El'gygytgyn reveal responses of plant communities to a range of climatic conditions that can help assess the possible impact of global warming on arctoboreal ecosystems. Vegetation associated with climatic optima suggests two types of interglacial responses: one is dominated by deciduous taxa (the postglacial thermal maximum (PGTM) and marine isotope stage (MIS5)) and the second by evergreen conifers (MIS11, MIS31). The MIS11 forests show a similarity to Picea-Larix-Betula-Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the modern boreal forest of the lower Amur valley in the Russian Far East. Despite vegetation differences during the thermal maxima, all four glacial-interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula-Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra in all interglaciations as they approach or achieve maximum warmth underscores the significance of this biome for modeling efforts. The El'gygytgyn data also suggest the possible elimination or massive reduction of arctic plant communities under extreme warm-earth scenarios.

Tectonics, climate, and the rise and demise of continental aquatic species richness hotspots.

PubMed

Neubauer, Thomas A; Harzhauser, Mathias; Georgopoulou, Elisavet; Kroh, Andreas; Mandic, Oleg

2015-09-15

Continental aquatic species richness hotspots are unevenly distributed across the planet. In present-day Europe, only two centers of biodiversity exist (Lake Ohrid on the Balkans and the Caspian Sea). During the Neogene, a wide variety of hotspots developed in a series of long-lived lakes. The mechanisms underlying the presence of richness hotspots in different geological periods have not been properly examined thus far. Based on Miocene to Recent gastropod distributions, we show that the existence and evolution of such hotspots in inland-water systems are tightly linked to the geodynamic history of the European continent. Both past and present hotspots are related to the formation and persistence of long-lived lake systems in geological basins or to isolation of existing inland basins and embayments from the marine realm. The faunal evolution within hotspots highly depends on warm climates and surface area. During the Quaternary icehouse climate and extensive glaciations, limnic biodiversity sustained a severe decline across the continent and most former hotspots disappeared. The Recent gastropod distribution is mainly a geologically young pattern formed after the Last Glacial Maximum (19 ky) and subsequent formation of postglacial lakes. The major hotspots today are related to long-lived lakes in preglacially formed, permanently subsiding geological basins.

Tectonics, climate, and the rise and demise of continental aquatic species richness hotspots

PubMed Central

Neubauer, Thomas A.; Harzhauser, Mathias; Georgopoulou, Elisavet; Kroh, Andreas; Mandic, Oleg

2015-01-01

Continental aquatic species richness hotspots are unevenly distributed across the planet. In present-day Europe, only two centers of biodiversity exist (Lake Ohrid on the Balkans and the Caspian Sea). During the Neogene, a wide variety of hotspots developed in a series of long-lived lakes. The mechanisms underlying the presence of richness hotspots in different geological periods have not been properly examined thus far. Based on Miocene to Recent gastropod distributions, we show that the existence and evolution of such hotspots in inland-water systems are tightly linked to the geodynamic history of the European continent. Both past and present hotspots are related to the formation and persistence of long-lived lake systems in geological basins or to isolation of existing inland basins and embayments from the marine realm. The faunal evolution within hotspots highly depends on warm climates and surface area. During the Quaternary icehouse climate and extensive glaciations, limnic biodiversity sustained a severe decline across the continent and most former hotspots disappeared. The Recent gastropod distribution is mainly a geologically young pattern formed after the Last Glacial Maximum (19 ky) and subsequent formation of postglacial lakes. The major hotspots today are related to long-lived lakes in preglacially formed, permanently subsiding geological basins. PMID:26305934

Tracing glacial refugia of Triturus newts based on mitochondrial DNA phylogeography and species distribution modeling

PubMed Central

2013-01-01

Introduction The major climatic oscillations during the Quaternary Ice Age heavily influenced the distribution of species and left their mark on intraspecific genetic diversity. Past range shifts can be reconstructed with the aid of species distribution modeling and phylogeographical analyses. We test the responses of the different members of the genus Triturus (i.e. the marbled and crested newts) as the climate shifted from the previous glacial period (the Last Glacial Maximum, ~21 Ka) to the current interglacial. Results We present the results of a dense mitochondrial DNA phylogeography (visualizing genetic diversity within and divergence among populations) and species distribution modeling (using two different climate simulations) for the nine Triturus species on composite maps. Conclusions The combined use of species distribution modeling and mitochondrial phylogeography provides insight in the glacial contraction and postglacial expansion of Triturus. The combined use of the two independent techniques yields a more complete understanding of the historical biogeography of Triturus than both approaches would on their own. Triturus newts generally conform to the ‘southern richness and northern purity’ paradigm, but we also find more intricate patterns, such as the absence of genetic variation and suitable area at the Last Glacial Maximum (T. dobrogicus), an ‘extra-Mediterranean’ refugium in the Carpathian Basin (T. cristatus), and areas where species displaced one another postglacially (e.g. T. macedonicus and western T. karelinii). We provide a biogeographical scenario for Triturus, showing the positions of glacial refugia, the regions that were postglacially colonized and the areas where species displaced one another as they shifted their ranges. PMID:23514662

Tracing glacial refugia of Triturus newts based on mitochondrial DNA phylogeography and species distribution modeling.

PubMed

Wielstra, Ben; Crnobrnja-Isailović, Jelka; Litvinchuk, Spartak N; Reijnen, Bastian T; Skidmore, Andrew K; Sotiropoulos, Konstantinos; Toxopeus, Albertus G; Tzankov, Nikolay; Vukov, Tanja; Arntzen, Jan W

2013-03-20

The major climatic oscillations during the Quaternary Ice Age heavily influenced the distribution of species and left their mark on intraspecific genetic diversity. Past range shifts can be reconstructed with the aid of species distribution modeling and phylogeographical analyses. We test the responses of the different members of the genus Triturus (i.e. the marbled and crested newts) as the climate shifted from the previous glacial period (the Last Glacial Maximum, ~21 Ka) to the current interglacial. We present the results of a dense mitochondrial DNA phylogeography (visualizing genetic diversity within and divergence among populations) and species distribution modeling (using two different climate simulations) for the nine Triturus species on composite maps. The combined use of species distribution modeling and mitochondrial phylogeography provides insight in the glacial contraction and postglacial expansion of Triturus. The combined use of the two independent techniques yields a more complete understanding of the historical biogeography of Triturus than both approaches would on their own. Triturus newts generally conform to the 'southern richness and northern purity' paradigm, but we also find more intricate patterns, such as the absence of genetic variation and suitable area at the Last Glacial Maximum (T. dobrogicus), an 'extra-Mediterranean' refugium in the Carpathian Basin (T. cristatus), and areas where species displaced one another postglacially (e.g. T. macedonicus and western T. karelinii). We provide a biogeographical scenario for Triturus, showing the positions of glacial refugia, the regions that were postglacially colonized and the areas where species displaced one another as they shifted their ranges.

Recent topographic evolution and erosion of the deglaciated Washington Cascades inferred from a stochastic landscape evolution model

NASA Astrophysics Data System (ADS)

Moon, Seulgi; Shelef, Eitan; Hilley, George E.

2015-05-01

In this study, we model postglacial surface processes and examine the evolution of the topography and denudation rates within the deglaciated Washington Cascades to understand the controls on and time scales of landscape response to changes in the surface process regime after deglaciation. The postglacial adjustment of this landscape is modeled using a geomorphic-transport-law-based numerical model that includes processes of river incision, hillslope diffusion, and stochastic landslides. The surface lowering due to landslides is parameterized using a physically based slope stability model coupled to a stochastic model of the generation of landslides. The model parameters of river incision and stochastic landslides are calibrated based on the rates and distribution of thousand-year-time scale denudation rates measured from cosmogenic 10Be isotopes. The probability distributions of those model parameters calculated based on a Bayesian inversion scheme show comparable ranges from previous studies in similar rock types and climatic conditions. The magnitude of landslide denudation rates is determined by failure density (similar to landslide frequency), whereas precipitation and slopes affect the spatial variation in landslide denudation rates. Simulation results show that postglacial denudation rates decay over time and take longer than 100 kyr to reach time-invariant rates. Over time, the landslides in the model consume the steep slopes characteristic of deglaciated landscapes. This response time scale is on the order of or longer than glacial/interglacial cycles, suggesting that frequent climatic perturbations during the Quaternary may produce a significant and prolonged impact on denudation and topography.

High evolutionary potential of marine zooplankton

PubMed Central

Peijnenburg, Katja T C A; Goetze, Erica

2013-01-01

Abstract Open ocean zooplankton often have been viewed as slowly evolving species that have limited capacity to respond adaptively to changing ocean conditions. Hence, attention has focused on the ecological responses of zooplankton to current global change, including range shifts and changing phenology. Here, we argue that zooplankton also are well poised for evolutionary responses to global change. We present theoretical arguments that suggest plankton species may respond rapidly to selection on mildly beneficial mutations due to exceptionally large population size, and consider the circumstantial evidence that supports our inference that selection may be particularly important for these species. We also review all primary population genetic studies of open ocean zooplankton and show that genetic isolation can be achieved at the scale of gyre systems in open ocean habitats (100s to 1000s of km). Furthermore, population genetic structure often varies across planktonic taxa, and appears to be linked to the particular ecological requirements of the organism. In combination, these characteristics should facilitate adaptive evolution to distinct oceanographic habitats in the plankton. We conclude that marine zooplankton may be capable of rapid evolutionary as well as ecological responses to changing ocean conditions, and discuss the implications of this view. We further suggest two priority areas for future research to test our hypothesis of high evolutionary potential in open ocean zooplankton, which will require (1) assessing how pervasive selection is in driving population divergence and (2) rigorously quantifying the spatial and temporal scales of population differentiation in the open ocean. Recent attention has focused on the ecological responses of open ocean zooplankton to current global change, including range shifts and changing phenology. Here, we argue that marine zooplankton also are well poised for evolutionary responses to global change. PMID:24567838

Horizontal variability of the marine boundary layer structure upwind of San Nicolas Island during FIRE, 1987

NASA Technical Reports Server (NTRS)

Jensen, Douglas R.

1990-01-01

During the months of June and July 1987, the Marine Stratocumulus Intensive Field Observation Experiment of First ISCCP Regional Experiment (FIRE) was conducted in the Southern California offshore area in the vicinity of San Nicolas Island (SNI). The Naval Ocean Systems Center (NOSC) airborne platform was utilized during FIRE to investigate the upwind low level horizontal variability of the marine boundary layer structure to determine the representativeness of SNI-based measurements to upwind open ocean conditions. The NOSC airborne meteorological platform made three flights during FIRE, two during clear sky conditions (19 and 23 July), and one during two stratus conditions (15 July). The boundary layer structure variations associated with the stratus clouds of 15 July 1987 are discussed. Profiles of air temperature (AT) and relative humidity (RH) taken 'at' and 'upwind' of SNI do show differences between the so-called open ocean conditions and those taken near the island. However, the observed difference cannot be uniquely identified to island effects, especially since the upwind fluctuations of AT and RH bound the SNI measurements. Total optical depths measures at SNI do not appear to be greatly affected by any surface based aerosol effects created by the island and could therefore realistically represent open ocean conditions. However, if one were to use the SNI aerosol measurements to predict ship to ship EO propagation conditions, significant errors could be introduced due to the increased number of surface aerosols observed near SNI which may not be, and were not, characteristic of open ocean conditions. Sea surface temperature measurements taken at the island will not, in general, represent those upwind open ocean conditions. Also, since CTT's varied appreciably along the upwind radials, measurements of CTT over the island may not be representative of actual open ocean CTT's.

Marine aerosol formation from biogenic iodine emissions.

PubMed

O'Dowd, Colin D; Jimenez, Jose L; Bahreini, Roya; Flagan, Richard C; Seinfeld, John H; Hämeri, Kaarle; Pirjola, Liisa; Kulmala, Markku; Jennings, S Gerard; Hoffmann, Thorsten

2002-06-06

The formation of marine aerosols and cloud condensation nuclei--from which marine clouds originate--depends ultimately on the availability of new, nanometre-scale particles in the marine boundary layer. Because marine aerosols and clouds scatter incoming radiation and contribute a cooling effect to the Earth's radiation budget, new particle production is important in climate regulation. It has been suggested that sulphuric acid derived from the oxidation of dimethyl sulphide is responsible for the production of marine aerosols and cloud condensation nuclei. It was accordingly proposed that algae producing dimethyl sulphide play a role in climate regulation, but this has been difficult to prove and, consequently, the processes controlling marine particle formation remains largely undetermined. Here, using smog chamber experiments under coastal atmospheric conditions, we demonstrate that new particles can form from condensable iodine-containing vapours, which are the photolysis products of biogenic iodocarbons emitted from marine algae. Moreover, we illustrate, using aerosol formation models, that concentrations of condensable iodine-containing vapours over the open ocean are sufficient to influence marine particle formation. We suggest therefore that marine iodocarbon emissions have a potentially significant effect on global radiative forcing.

33 CFR 117.795 - Jamaica Bay and Connecting Waterways.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Connecting Waterways. (a) The draw of the Marine Parkway bridge, mile 3.0 over Rockaway Inlet, shall open on signal Monday through Friday from 8 a.m. to 4 p.m. At all other times, the draw shall open on signal if at least eight hours notice is given; however, the draw shall open on signal if at least a one hour...

33 CFR 117.795 - Jamaica Bay and Connecting Waterways.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Connecting Waterways. (a) The draw of the Marine Parkway bridge, mile 3.0 over Rockaway Inlet, shall open on signal Monday through Friday from 8 a.m. to 4 p.m. At all other times, the draw shall open on signal if at least eight hours notice is given; however, the draw shall open on signal if at least a one hour...

33 CFR 117.795 - Jamaica Bay and Connecting Waterways.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Connecting Waterways. (a) The draw of the Marine Parkway bridge, mile 3.0 over Rockaway Inlet, shall open on signal Monday through Friday from 8 a.m. to 4 p.m. At all other times, the draw shall open on signal if at least eight hours notice is given; however, the draw shall open on signal if at least a one hour...

33 CFR 117.795 - Jamaica Bay and Connecting Waterways.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Connecting Waterways. (a) The draw of the Marine Parkway bridge, mile 3.0 over Rockaway Inlet, shall open on signal Monday through Friday from 8 a.m. to 4 p.m. At all other times, the draw shall open on signal if at least eight hours notice is given; however, the draw shall open on signal if at least a one hour...

33 CFR 117.795 - Jamaica Bay and Connecting Waterways.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Connecting Waterways. (a) The draw of the Marine Parkway bridge, mile 3.0 over Rockaway Inlet, shall open on signal Monday through Friday from 8 a.m. to 4 p.m. At all other times, the draw shall open on signal if at least eight hours notice is given; however, the draw shall open on signal if at least a one hour...

50 CFR Figure 13 to Part 223 - Single Grid Hard TED Escape Opening

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Single Grid Hard TED Escape Opening 13 Figure 13 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND.... 223, Fig. 13 Figure 13 to Part 223—Single Grid Hard TED Escape Opening EC01JY91.060 [60 FR 15520, Mar...

50 CFR Figure 13 to Part 223 - Single Grid Hard TED Escape Opening

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Single Grid Hard TED Escape Opening 13 Figure 13 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND.... 223, Fig. 13 Figure 13 to Part 223—Single Grid Hard TED Escape Opening EC01JY91.060 [60 FR 15520, Mar...

50 CFR Figure 12 to Part 223 - Escape Opening & Cover Dimensions for 71-inch TED

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Escape Opening & Cover Dimensions for 71-inch TED 12 Figure 12 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL... ANADROMOUS SPECIES Pt. 223, Fig. 12 Figure 12 to Part 223—Escape Opening & Cover Dimensions for 71-inch TED...

50 CFR Figure 12 to Part 223 - Escape Opening & Cover Dimensions for 71-inch TED

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Escape Opening & Cover Dimensions for 71-inch TED 12 Figure 12 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL... ANADROMOUS SPECIES Pt. 223, Fig. 12 Figure 12 to Part 223—Escape Opening & Cover Dimensions for 71-inch TED...

Recent topographic evolution and erosion of the deglaciated Washington Cascades inferred from a stochastic landscape evolution model

NASA Astrophysics Data System (ADS)

Moon, S.; Shelef, E.; Hilley, G. E.

2013-12-01

The Washington Cascades is currently in topographic and erosional disequilibrium after deglaciation occurred around 11- 17 ka ago. The topography still shows the features inherited from prior alpine glacial processes (e.g., cirques, steep side-valleys, and flat valley bottoms), though postglacial processes are currently denuding this landscape. Our previous study in this area calculated the thousand-year-timescale denudation rates using cosmogenic 10Be concentration (CRN-denudation rates), and showed that they were ~ four times higher than million-year-timescale uplift rates. In addition, the spatial distribution of denudation rates showed a good correlation with a factor-of-ten variation in precipitation. We interpreted this correlation as reflecting the sensitivity of landslide triggering in over-steepened deglaciated topography to precipitation, which produced high denudation rates in wet areas that experienced frequent landsliding. We explored this interpretation using a model of postglacial surface processes that predicts the evolution of the topography and denudation rates within the deglaciated Washington Cascades. Specifically, we used the model to understand the controls on and timescales of landscape response to changes in the surface process regime after deglaciation. The postglacial adjustment of this landscape is modeled using a geomorphic-transport-law-based numerical model that includes processes of river incision, hillslope diffusion, and stochastic landslides. The surface lowering due to landslides is parameterized using a physically-based slope stability model coupled to a stochastic model of the generation of landslides. The model parameters of river incision and stochastic landslides are calibrated based on the rates and distribution of thousand-year-timescale denudation rates measured from cosmogenic 10Be isotopes. The probability distribution of model parameters required to fit the observed denudation rates shows comparable ranges from previous studies in similar rock types and climatic conditions. The calibrated parameters suggest that the dominant sediment source of river sediments originates from stochastic landslides. The magnitude of landslide denudation rates is determined by failure density (similar to landslide frequency), while their spatial distribution is largely controlled by precipitation and slope angles. Simulation results show that denudation rates decay over time and take approximately 130-180 ka to reach steady-state rates. This response timescale is longer than glacial/interglacial cycles, suggesting that frequent climatic perturbations during the Quaternary may prevent these types of landscapes from reaching a dynamic equilibrium with postglacial processes.

Molecular biogeography of Europe: Pleistocene cycles and postglacial trends

PubMed Central

Schmitt, Thomas

2007-01-01

The climatic cycles with subsequent glacial and intergalcial periods have had a great impact on the distribution and evolution of species. Using genetic analytical tools considerably increased our understanding of these processes. In this review I therefore give an overview of the molecular biogeography of Europe. For means of simplification, I distinguish between three major biogeographical entities: (i) "Mediterranean" with Mediterranean differentiation and dispersal centres, (ii) "Continental" with extra-Mediterranean centres and (iii) "Alpine" and/or "Arctic" with recent alpine and/or arctic distribution patterns. These different molecular biogeographical patterns are presented using actual examples. Many "Mediterranean" species are differentiated into three major European genetic lineages, which are due to glacial isolation in the three major Mediterranean peninsulas. Postglacial expansion in this group of species is mostly influenced by the barriers of the Pyrenees and the Alps with four resulting main patterns of postglacial range expansions. However, some cases are known with less than one genetic lineage per Mediterranean peninsula on the one hand, and others with a considerable genetic substructure within each of the Mediterranean peninsulas, Asia Minor and the Maghreb. These structures within the Mediterranean sub-centres are often rather strong and in several cases even predate the Pleistocene. For the "Continental" species, it could be shown that the formerly supposed postglacial spread from eastern Palearctic expansion centres is mostly not applicable. Quite the contrary, most of these species apparently had extra-Mediterranean centres of survival in Europe with special importance of the perialpine regions, the Carpathian Basin and parts of the Balkan Peninsula. In the group of "Alpine" and/or "Arctic" species, several molecular biogeographical patterns have been found, which support and improve the postulates based on distribution patterns and pollen records. Thus, genetic studies support the strong linkage between southwestern Alps and Pyrenees, northeastern Alps and Carpathians as well as southeastern Alps and the Dinaric mountain systems, hereby allowing conclusions on the glacial distribution patterns of these species. Furthermore, genetic analyses of arctic-alpine disjunct species support their broad distribution in the periglacial areas at least during the last glacial period. The detailed understanding of the different phylogeographical structures is essential for the management of the different evolutionary significant units of species and the conservation of their entire genetic diversity. Furthermore, the distribution of genetic diversity due to biogeographical reasons helps understanding the differing regional vulnerabilities of extant populations. PMID:17439649

An Assessment of the Length and Variability of Mercury's Magnetotail

NASA Technical Reports Server (NTRS)

Milan, S. E.; Slavin, J. A.

2011-01-01

We employ Mariner 10 measurements of the interplanetary magnetic field in the vicinity of Mercury to estimate the rate of magnetic reconnection between the interplanetary magnetic field and the Hermean magnetosphere. We derive a time-series of the open magnetic flux in Mercury's magnetosphere. from which we can deduce the length of the magnetotail The length of the magnetotail is shown to be highly variable. with open field lines stretching between 15R(sub H) and 8S0R(sub H) downstream of the planet (median 150R(sub H)). Scaling laws allow the tail length at perihelion to be deduced from the aphelion Mariner 10 observations.

Arctic sea ice melt leads to atmospheric new particle formation.

PubMed

Dall Osto, M; Beddows, D C S; Tunved, P; Krejci, R; Ström, J; Hansson, H-C; Yoon, Y J; Park, Ki-Tae; Becagli, S; Udisti, R; Onasch, T; O Dowd, C D; Simó, R; Harrison, Roy M

2017-06-12

Atmospheric new particle formation (NPF) and growth significantly influences climate by supplying new seeds for cloud condensation and brightness. Currently, there is a lack of understanding of whether and how marine biota emissions affect aerosol-cloud-climate interactions in the Arctic. Here, the aerosol population was categorised via cluster analysis of aerosol size distributions taken at Mt Zeppelin (Svalbard) during a 11 year record. The daily temporal occurrence of NPF events likely caused by nucleation in the polar marine boundary layer was quantified annually as 18%, with a peak of 51% during summer months. Air mass trajectory analysis and atmospheric nitrogen and sulphur tracers link these frequent nucleation events to biogenic precursors released by open water and melting sea ice regions. The occurrence of such events across a full decade was anti-correlated with sea ice extent. New particles originating from open water and open pack ice increased the cloud condensation nuclei concentration background by at least ca. 20%, supporting a marine biosphere-climate link through sea ice melt and low altitude clouds that may have contributed to accelerate Arctic warming. Our results prompt a better representation of biogenic aerosol sources in Arctic climate models.

Sources of reactive nitrogen in marine aerosol over the Northwest Pacific Ocean in spring

NASA Astrophysics Data System (ADS)

Luo, Li; Kao, Shuh-Ji; Bao, Hongyan; Xiao, Huayun; Xiao, Hongwei; Yao, Xiaohong; Gao, Huiwang; Li, Jiawei; Lu, Yangyang

2018-05-01

Atmospheric deposition of long-range transport of anthropogenic reactive nitrogen (Nr, mainly comprised of NHx, NOy and water-soluble organic nitrogen, WSON) from continents may have profound impact on marine biogeochemistry. In addition, surface ocean dissolved organic nitrogen (DON) may also contribute to aerosol WSON in the overlying atmosphere. Despite the importance of off-continent dispersion and Nr interactions at the atmosphere-ocean boundary, our knowledge of the sources of various nitrogen species in the atmosphere over the open ocean remains limited due to insufficient observations. We conducted two cruises in the spring of 2014 and 2015 from the coast of China through the East China seas (ECSs, i.e. the Yellow Sea and East China Sea) to the open ocean (i.e. the Northwest Pacific Ocean, NWPO). Concentrations of water-soluble total nitrogen (WSTN), NO3- and NH4+, as well as the δ15N of WSTN and NO3- in marine aerosol, were measured during both cruises. In the spring of 2015, we also analysed the concentrations and δ15N of NO3- and the DON of surface seawater (SSW; at a depth of 5 m) along the cruise track. Aerosol NO3-, NH4+ and WSON decreased logarithmically (1-2 orders of magnitude) with distance from the shore, reflecting strong anthropogenic emission sources of NO3-, NH4+ and WSON in China. Average aerosol NO3- and NH4+ concentrations were significantly higher in 2014 (even in the remote NWOP) than in 2015 due to the stronger wind field in 2014, underscoring the role of the Asian winter monsoon in the seaward transport of anthropogenic NO3- and NH4+. However, the background aerosol WSON over the NWPO in 2015 (13.3 ± 8.5 nmol m-3) was similar to that in 2014 (12.2 ± 6.3 nmol m-3), suggesting an additional non-anthropogenic WSON source in the open ocean. Obviously, marine DON emissions should be considered in model and field assessments of net atmospheric WSON deposition in the open ocean. This study contributes information on parallel isotopic marine DON composition and aerosol Nr datasets, but more research is required to explore complex Nr sources and deposition processes in order to advance our understanding of anthropogenic influences on the marine nitrogen cycle and nitrogen exchange at land-ocean and atmosphere-ocean interfaces.

Events Calendar: Smithsonian Marine Ecosystems Exhibit: Smithsonian Marine

Science.gov Websites

Tours FREE | Behind-the-Scenes Tour of the Research Station tour participant Third Thursday of each month at 2PM - Free. Registration is required. Once a month we open our doors to the public to share scenes tours. All activities are included with the price of admission. FREE DAY | First Tuesday of each

78 FR 73097 - Ocean Dumping; Sabine-Neches Waterway (SNWW) Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-05

... of the Entrance Channel into the Gulf of Mexico, pursuant to the Marine Protection, Research and... exists, and if analysis of the dredged material indicates that it is suitable for open-water disposal... material from the Sabine-Neches Waterway, under the Marine Protection Research and Sanctuaries Act, 33 U.S...

Pentacyclic ingamine-type alkaloids, a new antiplasmodial pharmacophore from the marine sponge petrosid Ng5 Sp5

USDA-ARS?s Scientific Manuscript database

Two new pentacyclic ingamine- type alkaloids, namely 22(S)-hydroxyingamine A (2) and dihydroingenamine D (3), together with the known ingamine A (1) have been isolated from marine sponge Petrosid Ng5 Sp5 (Family: Petrosiidae) obtained from the open repository of National Cancer Institute, USA. The s...

Sensitivity of climate and Atlantic overturning circulation to uncertain ocean gateway configurations for the late Miocene

NASA Astrophysics Data System (ADS)

Bradshaw, C.; Lunt, D. J.; Flecker, R.; Martinez-Mendez, G.

2013-12-01

The palaeorecord documents late Miocene (11.6-5.3 Ma) climate to be much warmer and wetter than today yet CO2 reconstructions are similar to modern levels. Given the apparent decoupling between CO2 and warmth for this period we investigate here the role of the oceans. The late Miocene experienced significant tectonic change including the restriction of some of the last ocean gateways to close (Panama Gateway and Indonesian Seaway) and open (Bering Strait and Barents/Kara Sea). However, the timing and configuration of these tectonic changes is uncertain. The final closure of the Panama Gateway is dated to the Pliocene, but continental mammal exchange suggests the existence of a Central American archipelago from the mid-late Miocene. The Bering Strait is typically assumed to have opened at the very end of the late Miocene/early Pliocene based on diatom exchange, but other marine and terrestrial evidence points to a much earlier, perhaps intermittent, opening. The timing of the restriction of the Indonesian Seaway is very poorly constrained at middle Miocene to Pliocene. The Barents Sea and Kara Sea shelves are documented as having being subject to extensive glacial erosion and post-glacial uplift since the Pliocene and throughout the Quaternary but records of uplift and erosion during the earlier Cenozoic are limited. However, the presence of significant preglacial sediments suggests that this region underwent tectonic uplift, volcanism and subsequent erosion during the Eocene-Miocene period although the age assignment of the data remains controversial. The Panama Gateway has been suggested to influence North Atlantic Deep Water (NADW) production through numerous modelling studies, the Bering Strait has been suggested to greatly impact NADW during the Quaternary, and the strength of Indonesian Throughflow is hypothesised to influence Agulhas Leakage, which, in turn, has been speculated to influence Atlantic meridional overturning and thus NADW production. Here, we investigate how the opening and closing of these gateways might influence ocean circulation, and hence climate, with late Miocene boundary conditions using the fully coupled atmosphere-ocean-vegetation GCM HadCM3L with TRIFFID. We show how the model suggests these gateways in different configurations might influence NADW production, with results from all possible combinations of these three gateways presented and compared to the available proxy data. The climatic implications of the presence of the Barents Shelf and Kara Shelf land masses prior to their final erosion has not been the subject of much research, either through modelling or data interpretation, and indeed many model simulations for the Miocene do not include these shelves as land masses at all. Here we also test our hypothesis that these land masses also impact NADW production through the restriction of the exchange of water between the Arctic Ocean and the Greenland-Iceland-Norwegian Sea. We hypothesize that their presence as land masses results in a saltier North Atlantic than occurs after their erosion; without the land masses there, the North Atlantic would experience more influence from the East Greenland Current (colder/fresher) and less influence of the Irminger Current (warmer/saltier).

Did the Mississippian Lodgepole buildup at Dickinson Field (North Dakota) form as a gas seep ({open_quotes}vent{close_quotes}) community?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longman, M.W.

1996-10-01

The Lower Mississippian Lodgepole carbonate buildup reservoir at Dickinson Field in Stark County, North Dakota, has been widely reported as being a Waulsortian (or Waulsortian-like) mound. The term {open_quotes}Waulsortian mound{close_quotes} is used for a variety of Early Mississippian carbonate buildups that share a number of features including an abundance of carbonate mud, a {open_quotes}framework{close_quotes} of organisms such as fenestrate bryozoans and crinoids that tended to trap or baffle sediment, and a general absence of marine-cemented reef framework. Although the age of the Lodgepole mound at Dickinson Field qualifies it to be a Waulsortian mound, petrographic study of cores reveals thatmore » the reservoir rocks are quite unlike those in true Waulsortian mounds. Instead of being dominated by carbonate mud, the Lodgepole mound core is dominated by marine cement. Furthermore, ostracods and microbial limestones are common in the mound core where they occur with crinoid debris and small amounts of bryozoan, coral, and brachiopod debris. The abundant microbial limestones and marine cement indicate that the Dickinson mound formed as a lithified reef on the sea floor rather than as a Waulsortian mud mound. The microbial limestones, marine cement, and common ostracods in the mount core, and the fact that the mound nucleated almost directly o top of the Bakken Shale, suggest that the Dickinson Lodgepole mound formed at the site of a submarine spring and gas seep.« less

Sequence stratigraphic re-interpretation of [open quotes]stray[close quotes] sandstones in the Cretaceous Mancos Shale, Book Cliffs, Utah: Implications for exploration models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hampson, G.J.; Howell, J.A.; Flint, S.S.

1996-01-01

The Mancos Shale, Book Cliffs, eastern Utah, represents the open marine mudstones of the Cretaceous Western Interior Seaway and contains a number of detached sandstone bodies ([open quotes]Mancos B[close quotes]) which are located 30-150 km down depositional dip from contemporaneous highstand shoreline deposits in the Blackhawk Formation. Examination of these [open quotes]stray[close quotes] sandstones reveals that they do not represent deep water deposition, as previously supposed, but instead comprise three shallow marine facies associations; (1) tidally-influenced fluvial channel fills, (2) fluvially-dominated delta front successions and (3) low-energy shorelines. Tidally-influenced fluvial channel fills are commonly stacked into multistorey bodies at discretemore » stratigraphic levels, thereby defining incised valley fill (IVF) networks. Fluvially-dominated deltas are eroded into by, and lie at the down-dip terminations of, IVFs and are therefore interpreted as falling stage and lowstand shorelines. Low-energy shorelines are inferred to lie along strike from these deltas. The above shallow marine deposits have been mapped at five discrete stratigraphic horizons, which can be either traced or projected up-dip to previously-documented IVFs in the Blackhawk Formation. Their paleocurrents imply that falling stage and lowstand shoreline trends were sub-parallel to mapped highstand shorelines, although there is evidence for a perpendicular lowstand shoreline trend in the east of the study area. This facies and sequence stratigraphic re-interpretation enables predictive exploration modelling of subsurface [open quotes]Mancos B[close quotes] gas reservoir sandstones.« less

Sequence stratigraphic re-interpretation of {open_quotes}stray{close_quotes} sandstones in the Cretaceous Mancos Shale, Book Cliffs, Utah: Implications for exploration models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hampson, G.J.; Howell, J.A.; Flint, S.S.

1996-12-31

The Mancos Shale, Book Cliffs, eastern Utah, represents the open marine mudstones of the Cretaceous Western Interior Seaway and contains a number of detached sandstone bodies ({open_quotes}Mancos B{close_quotes}) which are located 30-150 km down depositional dip from contemporaneous highstand shoreline deposits in the Blackhawk Formation. Examination of these {open_quotes}stray{close_quotes} sandstones reveals that they do not represent deep water deposition, as previously supposed, but instead comprise three shallow marine facies associations; (1) tidally-influenced fluvial channel fills, (2) fluvially-dominated delta front successions and (3) low-energy shorelines. Tidally-influenced fluvial channel fills are commonly stacked into multistorey bodies at discrete stratigraphic levels, thereby definingmore » incised valley fill (IVF) networks. Fluvially-dominated deltas are eroded into by, and lie at the down-dip terminations of, IVFs and are therefore interpreted as falling stage and lowstand shorelines. Low-energy shorelines are inferred to lie along strike from these deltas. The above shallow marine deposits have been mapped at five discrete stratigraphic horizons, which can be either traced or projected up-dip to previously-documented IVFs in the Blackhawk Formation. Their paleocurrents imply that falling stage and lowstand shoreline trends were sub-parallel to mapped highstand shorelines, although there is evidence for a perpendicular lowstand shoreline trend in the east of the study area. This facies and sequence stratigraphic re-interpretation enables predictive exploration modelling of subsurface {open_quotes}Mancos B{close_quotes} gas reservoir sandstones.« less

Development of the mixed conifer forest in northern New Mexico and its relationship to Holocene environmental change

NASA Astrophysics Data System (ADS)

Anderson, R. Scott; Jass, Renata B.; Toney, Jaime L.; Allen, Craig D.; Cisneros-Dozal, Luz M.; Hess, Marcey; Heikoop, Jeff; Fessenden, Julianna

2008-03-01

Chihuahueños Bog (2925 m) in the Jemez Mountains of northern New Mexico contains one of the few records of late-glacial and postglacial development of the mixed conifer forest in southwestern North America. The Chihuahueños Bog record extends to over 15,000 cal yr BP. An Artemisia steppe, then an open Picea woodland grew around a small pond until ca. 11,700 cal yr BP when Pinus ponderosa became established. C/N ratios, δ13C and δ15N values indicate both terrestrial and aquatic organic matter was incorporated into the sediment. Higher percentages of aquatic algae and elevated C/N ratios indicate higher lake levels at the opening of the Holocene, but a wetland developed subsequently as climate warmed. From ca. 8500 to 6400 cal yr BP the pond desiccated in what must have been the driest period of the Holocene there. C/N ratios declined to their lowest Holocene levels, indicating intense decomposition in the sediment. Wetter conditions returned after 6400 cal yr BP, with conversion of the site to a sedge bog as groundwater levels rose. Higher charcoal influx rates after 6400 cal yr BP probably result from greater biomass production rates. Only minor shifts in the overstory species occurred during the Holocene, suggesting that mixed conifer forest dominated throughout the record.

Development of the mixed conifer forest in northern New Mexico and its relationship to Holocene environmental change

USGS Publications Warehouse

Anderson, R. Scott; Jass, R.B.; Toney, J.L.; Allen, Craig D.; Cisneros-Dozal, L. M.; Hess, M.; Heikoop, Jeff; Fessenden, J.

2008-01-01

Chihuahueños Bog (2925 m) in the Jemez Mountains of northern New Mexico contains one of the few records of late-glacial and postglacial development of the mixed conifer forest in southwestern North America. The Chihuahueños Bog record extends to over 15,000 cal yr BP. AnArtemisiasteppe, then an openPiceawoodland grew around a small pond until ca. 11,700 cal yr BP whenPinus ponderosabecame established. C/N ratios,δ 13C andδ 15N values indicate both terrestrial and aquatic organic matter was incorporated into the sediment. Higher percentages of aquatic algae and elevated C/N ratios indicate higher lake levels at the opening of the Holocene, but a wetland developed subsequently as climate warmed. From ca. 8500 to 6400 cal yr BP the pond desiccated in what must have been the driest period of the Holocene there. C/N ratios declined to their lowest Holocene levels, indicating intense decomposition in the sediment. Wetter conditions returned after 6400 cal yr BP, with conversion of the site to a sedge bog as groundwater levels rose. Higher charcoal influx rates after 6400 cal yr BP probably result from greater biomass production rates. Only minor shifts in the overstory species occurred during the Holocene, suggesting that mixed conifer forest dominated throughout the record.

Does terrestrial epidemiology apply to marine systems?

USGS Publications Warehouse

McCallum, Hamish I.; Kuris, Armand M.; Harvell, C. Drew; Lafferty, Kevin D.; Smith, Garriet W.; Porter, James

2004-01-01

Most of epidemiological theory has been developed for terrestrial systems, but the significance of disease in the ocean is now being recognized. However, the extent to which terrestrial epidemiology can be directly transferred to marine systems is uncertain. Many broad types of disease-causing organism occur both on land and in the sea, and it is clear that some emergent disease problems in marine environments are caused by pathogens moving from terrestrial to marine systems. However, marine systems are qualitatively different from terrestrial environments, and these differences affect the application of modelling and management approaches that have been developed for terrestrial systems. Phyla and body plans are more diverse in marine environments and marine organisms have different life histories and probably different disease transmission modes than many of their terrestrial counterparts. Marine populations are typically more open than terrestrial ones, with the potential for long-distance dispersal of larvae. Potentially, this might enable unusually rapid propagation of epidemics in marine systems, and there are several examples of this. Taken together, these differences will require the development of new approaches to modelling and control of infectious disease in the ocean.

OOSTethys - Open Source Software for the Global Earth Observing Systems of Systems

NASA Astrophysics Data System (ADS)

Bridger, E.; Bermudez, L. E.; Maskey, M.; Rueda, C.; Babin, B. L.; Blair, R.

2009-12-01

An open source software project is much more than just picking the right license, hosting modular code and providing effective documentation. Success in advancing in an open collaborative way requires that the process match the expected code functionality to the developer's personal expertise and organizational needs as well as having an enthusiastic and responsive core lead group. We will present the lessons learned fromOOSTethys , which is a community of software developers and marine scientists who develop open source tools, in multiple languages, to integrate ocean observing systems into an Integrated Ocean Observing System (IOOS). OOSTethys' goal is to dramatically reduce the time it takes to install, adopt and update standards-compliant web services. OOSTethys has developed servers, clients and a registry. Open source PERL, PYTHON, JAVA and ASP tool kits and reference implementations are helping the marine community publish near real-time observation data in interoperable standard formats. In some cases publishing an OpenGeospatial Consortium (OGC), Sensor Observation Service (SOS) from NetCDF files or a database or even CSV text files could take only minutes depending on the skills of the developer. OOSTethys is also developing an OGC standard registry, Catalog Service for Web (CSW). This open source CSW registry was implemented to easily register and discover SOSs using ISO 19139 service metadata. A web interface layer over the CSW registry simplifies the registration process by harvesting metadata describing the observations and sensors from the “GetCapabilities” response of SOS. OPENIOOS is the web client, developed in PERL to visualize the sensors in the SOS services. While the number of OOSTethys software developers is small, currently about 10 around the world, the number of OOSTethys toolkit implementers is larger and growing and the ease of use has played a large role in spreading the use of interoperable standards compliant web services widely in the marine community.

Rapid uplift in Laguna del Maule volcanic field of the Andean Southern Volcanic Zone (Chile) measured by satellite radar interferometry

NASA Astrophysics Data System (ADS)

Feigl, K.; Ali, T.; Singer, B. S.; Pesicek, J. D.; Thurber, C. H.; Jicha, B. R.; Lara, L. E.; Hildreth, E. W.; Fierstein, J.; Williams-Jones, G.; Unsworth, M. J.; Keranen, K. M.

2011-12-01

The Laguna del Maule (LdM) volcanic field of the Andean Southern Volcanic Zone extends over 500 square kilometers and comprises more than 130 individual vents. As described by Hildreth et al. (2010), the history has been defined from sixty-eight Ar/Ar and K-Ar dates. Silicic eruptions have occurred throughout the past 3.7 Ma, including welded ignimbrite associated with caldera formation at 950 ka, small rhyolitic eruptions between 336 and 38 ka, and a culminating ring of 36 post-glacial rhyodacite and rhyolite coulees and domes that encircle the lake. Dating of five post-glacial flows implies that these silicic eruptions occurred within the last 25 kyr. Field relations indicate that initial eruptions comprised modest volumes of mafic rhyodacite magma that were followed by larger volumes of high silica rhyolite. The post-glacial flare-up of silicic magmatism from vents distributed around the lake, is unprecedented in the history of this volcanic field. Using satellite radar interferometry (InSAR), Fournier et al. (2010) measured uplift at a rate of more than 180 mm/year between 2007 and 2008 in a round pattern centered on the west side of LdM. More recent InSAR observations suggest that rapid uplift has continued from 2008 through early 2011. In contrast, Fournier et al. found no measurable deformation in an interferogram spanning 2003 through 2004. In this study, we model the deformation field using the General Inversion of Phase Technique (GIPhT), as described by Feigl and Thurber (2009). Two different models fit the data. The first model assumes a sill at ~5 km depth has been inflating at a rate of more than 20 million cubic meters per year since 2007. The second model assumes that the water level in the lake dropped at a rate of 20 m/yr from January 2007 through February 2010, thus reducing the load on an elastic simulation of the crust. The rate of intrusion inferred from InSAR is an order of magnitude higher than the average rate derived from well-dated arc volcanoes (Singer et al., 2008) and five times the average rate for the LdM field over the last 1.5 Myr (Hildreth et al., 2010). Moreover, post-glacial rhyolite flows along the western side of LdM exhibit paleo-shorelines several meters above the current lake level, suggesting that rapid uplift of this part of the volcanic field may have occurred episodically. The number and circular distribution of vents through which silicic magma of remarkably coherent major and trace element composition has erupted, and the lack of any post-glacial mafic lavas, suggest two end-member hypotheses: (1) an upper crustal silicic magma chamber of potentially caldera-forming dimensions has been evolving during the last 25 kyr, possibly to the present day, with magma leaking to the surface through a ring-fracture, or (2) a wide (> 20 km) MASH zone exists in the deep crust (Hildreth and Moorbath, 1988; Annen et al., 2006) which has repeatedly created and released batches of silicic magma since 25 ka.

Fe Isotope Composition of Neoproterozoic Post-Glacial "Cap Dolostones"

NASA Astrophysics Data System (ADS)

Halverson, G. P.

2005-12-01

The largest variations in the Fe isotope composition in the geological record are found in sedimentary rocks, presumably as the result of redox transformations of iron during mineral precipitation, microbial processing, and diagenesis (Johnson et al., Cont. Min. Petrol., 2003). Systematic trends in the variability of the Fe isotope composition of sulfide minerals formed in ancient marine black shales broadly mirror patterns in sulfur isotope data (Δ33S, Δ34S), which are consistent with geological and other geochemical evidence for the progressive oxidation of the earth's surface during the Precambrian (Rouxel et al., Science, 2005). Therefore, the record of the Fe isotope composition of minerals formed in the marine environment appears to be a promising proxy for the redox evolution of the ocean. We have developed a method to extract the marine Fe isotope composition from carbonates in an attempt to establish higher resolution records of changes in marine redox changes than permitted by black shale geochemistry. We have applied this method to the study of ca. 635 Ma iron-rich dolostones, which are found in Neoproterozoic successions worldwide and immediately post-date a purported snowball (Marinoan) glaciation during which time the deep ocean is thought to have become anoxic (Hoffman et al., Science, 1998), allowing its Fe isotopic composition to evolve towards the composition of relatively light (δ57Fe vs. IRMM-14 ~ -0.6‰) hydrothermal iron (Beard et al., Geology, 2003). Fe isotope compositions were measured relative to IRMM-14 in medium-resolution mode on a Neptune MC-ICP-MS with a long-term external (2σ) reproducibility of < 0.04‰/amu. Preliminary data on dolomite samples from Svalbard, northern Namibia and northwest Canada show a range in δ57Fe values from -0.65 to 0.04‰, similar to the range found in siderite and Fe-rich dolomite in ancient BIFs (Johsnon et al., 2003) and to values for the Namibian cap dolostone reported by Leighton et al. (Goldschmidt abstract, 2005), but distinctly lower than altered dolostones (δ57Fe = 0.10 - 1.02‰) in a Jurassic, organic-rich mudstone (Matthews et al., GCA, 2004). It is difficult to conclude at this time whether or not the relatively low δ57Fe composition of the cap dolostones is consistent with the Beard et al. (Geology, 2003) hypothesis due to large uncertainties in the solution-mineral fractionation factors for carbonates, the potential effects of diagenesis and biological influences on dolomite precipitation, and the possibility that the Marinoan deep ocean was euxinic.

Postglacial eruptive history, geochemistry, and recent seismicity of Aniakchak volcano, Alaska Peninsula

USGS Publications Warehouse

Bacon, Charles R.; Neal, Christina A.; Miller, Thomas P.; McGimsey, Robert G.; Nye, Christopher J.

2014-01-01

Future volcanic activity of Aniakchak could include hydromagmatic explosions, possibly followed by effusion or strombolian eruption of basaltic andesite to Plinian eruption of dacite. Another voluminous eruption, such as Aniakchak II, is considered unlikely in the near future.

Organic micropollutants in marine plastics debris from the open ocean and remote and urban beaches.

PubMed

Hirai, Hisashi; Takada, Hideshige; Ogata, Yuko; Yamashita, Rei; Mizukawa, Kaoruko; Saha, Mahua; Kwan, Charita; Moore, Charles; Gray, Holly; Laursen, Duane; Zettler, Erik R; Farrington, John W; Reddy, Christopher M; Peacock, Emily E; Ward, Marc W

2011-08-01

To understand the spatial variation in concentrations and compositions of organic micropollutants in marine plastic debris and their sources, we analyzed plastic fragments (∼10 mm) from the open ocean and from remote and urban beaches. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dichloro-diphenyl-trichloroethane and its metabolites (DDTs), polybrominated diphenyl ethers (PBDEs), alkylphenols and bisphenol A were detected in the fragments at concentrations from 1 to 10,000 ng/g. Concentrations showed large piece-to-piece variability. Hydrophobic organic compounds such as PCBs and PAHs were sorbed from seawater to the plastic fragments. PCBs are most probably derived from legacy pollution. PAHs showed a petrogenic signature, suggesting the sorption of PAHs from oil slicks. Nonylphenol, bisphenol A, and PBDEs came mainly from additives and were detected at high concentrations in some fragments both from remote and urban beaches and the open ocean. Copyright © 2011 Elsevier Ltd. All rights reserved.

Characteristics and origin of coarse gold in Late Pleistocene sediments of the Cariboo placer mining district, British Columbia, Canada

NASA Astrophysics Data System (ADS)

Eyles, N.

1995-02-01

The Cariboo placer mining district (1000 km 2) sited in the Interior Plateau of central British Columbia, Canada, is the premier placer gold mining district of the Province. Gold is recovered from three Late Pleistocene sedimentary facies: postglacial fluvial gravels (< 10 Ka), Late Wisconsin till (ca. 25-10 Ka), and "older" fluvial gravels (>25 Ka). This study reports the morphology (size, roundness, sphericity) of 1636 gold grains, ranging in size from 0.25 to 17 mm, recovered from 19 placer mines. Older gravels contain the smallest gold grains (mean grani size 1.53 mm), grains of intermediate size occur in till (2.23 mm) and the coarsest gold occurs in postglacial gravels (2.34 mm) with a mean of 1.93 mm for the mining district as a whole. The most common grain shapes are sub-rounded, discoidal (14.73% of the grain population), sub-angular, discoidal (10.88%), and sub-rounded, sub-discoidal (9.59%); the most angular grains occur in postglacial gravels. In-situ growth of coarse, angular grains is indicated by a "composite" grain structure, consisting of aggregates of gold particles welded together by high-grade (Ag = < 2%) filamentous gold; in-situ coarsening may be reliant on organic complexing agents produced below a dense forest cover. An evolutionary sequence of grain form, from angular aggregates to rounded "pumpkin seed" grains, is suggested. Rounded grains commonly show a crystalline structure which may result from the cold hammering of gold during transport; fracturing along crystal boundaries is common. Gold grains may undergo cycles of coarsening, rounding, diagenesis and breakup in response to repeated recycling through Pleistocene sedimentary environments.

Earthquake-induced deformations on ice-stream landforms in Kuusamo, eastern Finnish Lapland

NASA Astrophysics Data System (ADS)

Sutinen, Raimo; Hyvönen, Eija; Middleton, Maarit; Airo, Meri-Liisa

2018-01-01

Kuusamo in eastern Finnish Lapland is characterized by ice-streamlined landforms as well as clusters of historical and recent earthquakes (Mw < 4). Since recent earthquakes are often found to be located on the traces of postglacial faults (PGFs) within the Fennoscandian shield we postulate that some part of the ice-stream landforms have been deformed by the past earthquakes in Kuusamo. Airborne LiDAR (Light Detection And Ranging) DEMs (digital elevation models) revealed significant numbers of postglacial deformations, such as liquefaction deformations, rotational landslides, earth flows as well as kettle holes (craters), on the fluted surfaces within the Kuusamo ice-stream fan. We found these deformations to be a common feature on the Archean granitoid gneisses and within a 20 km wide and NW-SE oriented corridor between the major intrusives, the Iivaara nepheline syenite and the Näränkävaara gabbro. Of the paleolandslides, liquefaction morphologies were generally developed on the distal slopes (1.3-2.8%; 0.75-1.6°) of the streamlined forms. Sedimentary anisotropy, obtained with azimuthal electrical conductivity (σa; skin depth down to 3-6 m), of the deformed flutes significantly deviated from the non-deformed (clean) ones. The fields of the Pulju moraine, a subglacial landform, formed a grounding zone for the ice-streaming SW of the paleolandslide cluster. We therefore propose that both subglacial and postglacial earthquake-induced landforms are present in Kuusamo. No PGFs could be verified in the Kuusamo area, yet gravity, airborne magnetic, and LiDAR morphological lineaments suggest that the old Paleoproterozoic structures have been reactivated as strike-slip faults, due to the lithospheric plate stresses and glacio-isostatic adjustment (GIA).

Glacial Buzzcutting and Scarp Encroachment Limit the Height of Tropical Mountains

NASA Astrophysics Data System (ADS)

Cunningham, M.; Stark, C. P.; Kaplan, M. R.; Schaefer, J. M.; Winckler, G.

2016-12-01

In many mountain ranges hypsometric maxima occur between the glacial equilibrium line altitude (ELA) of the Last Glacial Maximum (LGM) and that of today. A common interpretation of this large-scale observation is that a "glacial buzzsaw" acting throughout the Pleistocene concentrated area within the altitudinal band of ELA fluctuation. This hypothesis remains controversial, however, as there are many examples of uplifted relict surfaces in heavily glaciated areas that occur near the ELA by coincidence. We have focused on the role of glacial erosion in the tropics, where it is spatially restricted to high elevations and temporally limited to global glacial maxima, but appears to have nevertheless truncated vertical orogen growth. Evidence of glacial buzzcutting in some of these ranges has been obscured by post-glacial destruction of glacial valleys by expanding fluvial catchments. We deduce that a duel between glacial buzzcuting and fluvially-driven scarp encroachment has proceeded throughout the Pleistocene in these places. In Costa Rica, we use 10Be and 3He surface-exposure age dating and topographic analysis to confirm that substantial glacial denudation took place at high elevations during the LGM, and employ topographic metrics there and in the Central Range of Taiwan to reveal shrinkage of glacially buzzcut surfaces driven by post-glacial scarp encroachment. These data cast new light on the buzzsaw hypothesis by showing that glacial erosion works with remarkable efficiency in the tropics, precisely where it is likely to be least effective. Our work also draws attention to landscapes with ambiguous signs of glacial erosion, as there are apparent instances of heavily modified, pre-LGM buzzcut surfaces in several tropical ranges. These perched, possibly pre-LGM landscapes may offer a window into previous phases of buzzcutting, and place speed limits on the rate of post-glacial scarp encroachment.

Inland post-glacial dispersal in East Asia revealed by mitochondrial haplogroup M9a'b.

PubMed

Peng, Min-Sheng; Palanichamy, Malliya Gounder; Yao, Yong-Gang; Mitra, Bikash; Cheng, Yao-Ting; Zhao, Mian; Liu, Jia; Wang, Hua-Wei; Pan, Hui; Wang, Wen-Zhi; Zhang, A-Mei; Zhang, Wen; Wang, Dong; Zou, Yang; Yang, Yang; Chaudhuri, Tapas Kumar; Kong, Qing-Peng; Zhang, Ya-Ping

2011-01-10

Archaeological studies have revealed a series of cultural changes around the Last Glacial Maximum in East Asia; whether these changes left any signatures in the gene pool of East Asians remains poorly indicated. To achieve deeper insights into the demographic history of modern humans in East Asia around the Last Glacial Maximum, we extensively analyzed mitochondrial DNA haplogroup M9a'b, a specific haplogroup that was suggested to have some potential for tracing the migration around the Last Glacial Maximum in East Eurasia. A total of 837 M9a'b mitochondrial DNAs (583 from the literature, while the remaining 254 were newly collected in this study) pinpointed from over 28,000 subjects residing across East Eurasia were studied here. Fifty-nine representative samples were further selected for total mitochondrial DNA sequencing so we could better understand the phylogeny within M9a'b. Based on the updated phylogeny, an extensive phylogeographic analysis was carried out to reveal the differentiation of haplogroup M9a'b and to reconstruct the dispersal histories. Our results indicated that southern China and/or Southeast Asia likely served as the source of some post-Last Glacial Maximum dispersal(s). The detailed dissection of haplogroup M9a'b revealed the existence of an inland dispersal in mainland East Asia during the post-glacial period. It was this dispersal that expanded not only to western China but also to northeast India and the south Himalaya region. A similar phylogeographic distribution pattern was also observed for haplogroup F1c, thus substantiating our proposition. This inland post-glacial dispersal was in agreement with the spread of the Mesolithic culture originating in South China and northern Vietnam.

Synchronisation of sedimentary records using tephra: A postglacial tephrochronological model for the Chilean Lake District

NASA Astrophysics Data System (ADS)

Fontijn, Karen; Rawson, Harriet; Van Daele, Maarten; Moernaut, Jasper; Abarzúa, Ana M.; Heirman, Katrien; Bertrand, Sébastien; Pyle, David M.; Mather, Tamsin A.; De Batist, Marc; Naranjo, Jose-Antonio; Moreno, Hugo

2016-04-01

Well-characterised tephra horizons deposited in various sedimentary environments provide a means of synchronising sedimentary archives. The use of tephra as a chronological tool is however still widely underutilised in southern Chile and Argentina. In this study we develop a postglacial tephrochronological model for the Chilean Lake District (ca. 38 to 42°S) by integrating terrestrial and lacustrine records. Tephra deposits preserved in lake sediments record discrete events even if they do not correspond to primary fallout. By combining terrestrial with lacustrine records we obtain the most complete tephrostratigraphic record for the area to date. We present glass geochemical and chronological data for key marker horizons that may be used to synchronise sedimentary archives used for palaeoenvironmental, palaeoclimatological and palaeoseismological purposes. Most volcanoes in the studied segment of the Southern Volcanic Zone, between Llaima and Calbuco, have produced at least one regional marker deposit resulting from a large explosive eruption (magnitude ≥ 4), some of which now have a significantly improved age estimate (e.g., the 10.5 ka Llaima Pumice eruption from Llaima volcano). Others, including several units from Puyehue-Cordón Caulle, are newly described here. We also find tephra related to the Cha1 eruption from Chaitén volcano in lake sediments up to 400 km north from source. Several clear marker horizons are now identified that should help refine age model reconstructions for various sedimentary archives. Our chronological model suggests three distinct phases of eruptive activity impacting the area, with an early-to-mid-Holocene period of relative quiescence. Extending our tephrochronological framework further south into Patagonia will allow a more detailed evaluation of the controls on the occurrence and magnitude of explosive eruptions throughout the postglacial.

46 CFR 52.01-100 - Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55). 52.01-100 Section 52.01-100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-100 Openings and compensation (modifies PG-32 through PG-39, PG-42...

46 CFR 52.01-100 - Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55). 52.01-100 Section 52.01-100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-100 Openings and compensation (modifies PG-32 through PG-39, PG-42...

46 CFR 52.01-100 - Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55). 52.01-100 Section 52.01-100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-100 Openings and compensation (modifies PG-32 through PG-39, PG-42...

46 CFR 52.01-100 - Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55). 52.01-100 Section 52.01-100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-100 Openings and compensation (modifies PG-32 through PG-39, PG-42...

46 CFR 52.01-100 - Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Openings and compensation (modifies PG-32 through PG-39, PG-42 through PG-55). 52.01-100 Section 52.01-100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-100 Openings and compensation (modifies PG-32 through PG-39, PG-42...

PAPARA(ZZ)I: An open-source software interface for annotating photographs of the deep-sea

NASA Astrophysics Data System (ADS)

Marcon, Yann; Purser, Autun

PAPARA(ZZ)I is a lightweight and intuitive image annotation program developed for the study of benthic megafauna. It offers functionalities such as free, grid and random point annotation. Annotations may be made following existing classification schemes for marine biota and substrata or with the use of user defined, customised lists of keywords, which broadens the range of potential application of the software to other types of studies (e.g. marine litter distribution assessment). If Internet access is available, PAPARA(ZZ)I can also query and use standardised taxa names directly from the World Register of Marine Species (WoRMS). Program outputs include abundances, densities and size calculations per keyword (e.g. per taxon). These results are written into text files that can be imported into spreadsheet programs for further analyses. PAPARA(ZZ)I is open-source and is available at http://papara-zz-i.github.io. Compiled versions exist for most 64-bit operating systems: Windows, Mac OS X and Linux.

Facies transition and depositional architecture of the Late Eocene tide-dominated delta in northern coast of Birket Qarun, Fayum, Egypt

NASA Astrophysics Data System (ADS)

Abdel-Fattah, Zaki A.

2016-07-01

Late Eocene successions in the Fayum Depression display notable facies transition from open-marine to brackish-marine realms. Stratigraphic and sedimentologic characteristics of the depositional facies are integrated with ichnological data for the recognition of four facies associations (FA1 to FA4). The transition from open-marine sandstones (FA1) to the brackish-marine deposits (FA2) heralds a transgressive - regressive dislocation. The shallowing- and coarsening-upward progradation from the basal prodelta mudstone-dominated facies (FA2a) to deltafront heterolithics (FA2b) and sandstone facies (FA2c) are overlain by finning-upward delta plain deposits which are expressed by the delta plain mudstone (FA2d) and erosive-based distributary channel fills (FA4). Prodelta/deltfront deposits of FA2 are arranged in thinning- and coarsening-upward parasequences which are stacked in a shallowing-upward progressive cycle. Shallow-marine fossiliferous sandstones (FA3) mark the basal part of each parasequence. Stratigraphic and depositional architectures reflect a tide-dominated delta rather than an estuarine and incised valley (IV) model. This can be evinced by the progressive facies architecture, absence of basal regional incision or a subaerial unconformity and the stratigraphic position above a maximum flooding surface (MFS), in addition to the presence of multiple tidally-influenced distributary channels. Stratigraphic and depositional characteristics of the suggested model resemble those of modern tide-dominated deltaic systems. Accordingly, this model contributes to our understanding of the depositional models for analogous brackish-marine environments, particularly tide-dominated deltas in the rock record.

Measurement and interpretation of crustal deformation rates associated with postglacial rebound

NASA Technical Reports Server (NTRS)

Davis, James L.

1993-01-01

This project involves obtaining Global Positioning System (GPS) measurements in Scandinavia, and using the measurements to estimate the viscosity profile of the Earth's mantle and to correct tide-gage measurements for the rebound effect. Several aspects of this project are reported.

The colonization history of British water vole (Arvicola amphibius (Linnaeus, 1758)): origins and development of the Celtic fringe

PubMed Central

Brace, Selina; Ruddy, Mark; Miller, Rebecca; Schreve, Danielle C.; Stewart, John R.; Barnes, Ian

2016-01-01

The terminal Pleistocene and Early Holocene, a period from 15 000 to 18 000 Before Present (BP), was critical in establishing the current Holarctic fauna, with temperate-climate species largely replacing cold-adapted ones at mid-latitudes. However, the timing and nature of this process remain unclear for many taxa, a point that impacts on current and future management strategies. Here, we use an ancient DNA dataset to test more directly postglacial histories of the water vole (Arvicola amphibius, formerly A. terrestris), a species that is both a conservation priority and a pest in different parts of its range. We specifically examine colonization of Britain, where a complex genetic structure can be observed today. Although we focus on population history at the limits of the species' range, the inclusion of additional European samples allows insights into European postglacial colonization events and provides a molecular perspective on water vole taxonomy. PMID:27122559

Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types

NASA Astrophysics Data System (ADS)

Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C.; Braithwaite, Colin; Kennedy, David M.; Spencer, Tom; Webster, Jody M.; Woodroffe, Colin D.

2014-05-01

In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy.

The colonization history of British water vole (Arvicola amphibius (Linnaeus, 1758)): origins and development of the Celtic fringe.

PubMed

Brace, Selina; Ruddy, Mark; Miller, Rebecca; Schreve, Danielle C; Stewart, John R; Barnes, Ian

2016-04-27

The terminal Pleistocene and Early Holocene, a period from 15 000 to 18 000 Before Present (BP), was critical in establishing the current Holarctic fauna, with temperate-climate species largely replacing cold-adapted ones at mid-latitudes. However, the timing and nature of this process remain unclear for many taxa, a point that impacts on current and future management strategies. Here, we use an ancient DNA dataset to test more directly postglacial histories of the water vole (Arvicola amphibius, formerly A terrestris), a species that is both a conservation priority and a pest in different parts of its range. We specifically examine colonization of Britain, where a complex genetic structure can be observed today. Although we focus on population history at the limits of the species' range, the inclusion of additional European samples allows insights into European postglacial colonization events and provides a molecular perspective on water vole taxonomy. © 2016 The Author(s).

Geoengineering impact of open ocean dissolution of olivine on atmospheric CO2, surface ocean pH and marine biology

NASA Astrophysics Data System (ADS)

Köhler, Peter; Abrams, Jesse F.; Völker, Christoph; Hauck, Judith; Wolf-Gladrow, Dieter A.

2013-03-01

Ongoing global warming induced by anthropogenic emissions has opened the debate as to whether geoengineering is a ‘quick fix’ option. Here we analyse the intended and unintended effects of one specific geoengineering approach, which is enhanced weathering via the open ocean dissolution of the silicate-containing mineral olivine. This approach would not only reduce atmospheric CO2 and oppose surface ocean acidification, but would also impact on marine biology. If dissolved in the surface ocean, olivine sequesters 0.28 g carbon per g of olivine dissolved, similar to land-based enhanced weathering. Silicic acid input, a byproduct of the olivine dissolution, alters marine biology because silicate is in certain areas the limiting nutrient for diatoms. As a consequence, our model predicts a shift in phytoplankton species composition towards diatoms, altering the biological carbon pumps. Enhanced olivine dissolution, both on land and in the ocean, therefore needs to be considered as ocean fertilization. From dissolution kinetics we calculate that only olivine particles with a grain size of the order of 1 μm sink slowly enough to enable a nearly complete dissolution. The energy consumption for grinding to this small size might reduce the carbon sequestration efficiency by ˜30%.

Blending geological observations and convection models to reconstruct mantle dynamics

NASA Astrophysics Data System (ADS)

Coltice, Nicolas; Bocher, Marie; Fournier, Alexandre; Tackley, Paul

2015-04-01

Knowledge of the state of the Earth mantle and its temporal evolution is fundamental to a variety of disciplines in Earth Sciences, from the internal dynamics to its many expressions in the geological record (postglacial rebound, sea level change, ore deposit, tectonics or geomagnetic reversals). Mantle convection theory is the centerpiece to unravel the present and past state of the mantle. For the past 40 years considerable efforts have been made to improve the quality of numerical models of mantle convection. However, they are still sparsely used to estimate the convective history of the solid Earth, in comparison to ocean or atmospheric models for weather and climate prediction. The main shortcoming is their inability to successfully produce Earth-like seafloor spreading and continental drift self-consistently. Recent convection models have begun to successfully predict these processes. Such breakthrough opens the opportunity to retrieve the recent dynamics of the Earth's mantle by blending convection models together with advanced geological datasets. A proof of concept will be presented, consisting in a synthetic test based on a sequential data assimilation methodology.

Iain Stewart Receives 2013 Athelstan Spilhaus Award: Response

NASA Astrophysics Data System (ADS)

Stewart, Iain

2014-01-01

It is really wonderful to receive this award and the recognition of AGU for my work. I've been a member of the Union since my Ph.D. days, 25 years or so ago, when I was working on earthquake faulting in Greece and Turkey. Its meetings were always the place that showcased geoscience at its most novel and exciting. It was the breadth of what was on offer that was so exhilarating. My doctoral studies had already opened up fairly wide vistas for me since my interest in Holocene earthquake activity also required an understanding of the Mediterranean's rich cultural history and the vagaries of millennial-scale climate fluctuations. Later, my research would distract me into farther-flung realms, such as volcanic faulting on Mount Etna, paleotsunamis along Aegean shores, even postglacial earthquakes in northern Scotland! Kindly colleagues would occasionally advise me to focus my efforts on a single substantive area of research, cautioning that my flighty research forays weren't conducive to climbing the academic ladder. I'm sure they were correct. Or would have been proved so if I hadn't been rescued by television.

A Project Approach to Teaching Aquaculture and Entrepreneurial Skills in the Cage Culture of Salmonids Program at the Marine Institute.

ERIC Educational Resources Information Center

Churchill, Edgar; Smith, Boyd

Between September and December 1986, the Marine Institute in Newfoundland, Canada, used a "projects approach" to train aquaculture workers for 10 new salmon farms to be opened in spring 1987 by a producers' cooperative. The projects approach combined instruction in the aquaculture skills needed to operate a salmon farm and the entrepreneurial…

Marine CCN Activation: A Battle Between Primary and Secondary Sources

NASA Astrophysics Data System (ADS)

Fossum, K. N.; Ovadnevaite, J.; Ceburnis, D.; Preissler, J.; O'Dowd, C. D. D.

2017-12-01

Low-altitude marine clouds are cooling components of the Earth's radiative budget, and the direct measurements of the properties of these cloud forming particles, called cloud condensation nuclei (CCN), helps modellers reconstruct aerosol-to-cloud droplet processes, improving climate predictions. In this study, CCN are directly measured (CCNC commercially available from Droplet Measurement Technologies, Inc.), resolving activation efficiency at varying supersaturated conditions. Previous studies show that sub-micron sea salt particulates activate competitively, reducing the cloud peak supersaturation and inhibiting the activation of sulphate particulates into cloud droplets, making chemical composition an important component in determining cloud droplet number concentration (CDNC). This effect and the sea salt numbers needed to induce it have not been previously studied long-term in the natural environment. As part of this work, data was analysed from a two month marine research ship campaign during the Antarctic Austral summer, in 2015. Ambient aerosol in the Scotia Sea region was sampled continuously, and through the use of multiple aerosol in-situ instruments, this study shows that CCN number in both the open ocean and ice-pack influenced air masses are largely proportionate to secondary aerosol. However, open ocean air masses show a significant primary aerosol influence which changes the aerosol characteristics. Higher sea salt mass concentrations in the open ocean lead to better CCN activation efficiencies. Coupled with high wind speeds and sea surface turbulence, open ocean air masses show a repression of the CDNC number compared with the theoretical values that should be expected with the sub-cloud aerosol number concentration. This is not seen in the ice-pack air masses. Work is ongoing, looking into a long-term North Atlantic marine aerosol data set, but it would appear that chemical composition plays a large role in aerosol to cloud droplet processes, and can initially restrict CDNC when sea salt is abundant and updraft velocities are relatively low.

33 CFR 127.1605 - Other sources of ignition.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Other sources of ignition. 127... sources of ignition. Each operator of a waterfront facility handling LHG shall ensure that in the marine transfer area for LHG— (a) There are no open fires or open flame lamps; (b) Heating equipment will not...

The Future of Marine Biogeochemistry, Ecosystems, and Societies

NASA Astrophysics Data System (ADS)

Bundy, Alida; Liu, Kon-Kee; Thomas, Helmuth

2013-05-01

The international project Integrated Marine Biogeochemistry and Ecosystem Research (IMBER) convenes an IMBIZO (a Zulu word meaning "a gathering") biennially, with a format of three concurrent, interacting workshops designed to synthesize information on topical research areas in marine science. IMBIZO III, held at the National Institute of Oceanography in Goa, India, focused on multidimensional approaches to challenges of global change in continental margins (CM), open ocean systems, and dependent human societies. More than 120 participants from 29 nations attended the meeting; the smaller workshop groups allowed in-depth discussions, and daily plenary sessions facilitated discussion among interdisciplinary experts.

Contribution to the Understanding of Particle Motion Perception in Marine Invertebrates.

PubMed

André, Michel; Kaifu, Kenzo; Solé, Marta; van der Schaar, Mike; Akamatsu, Tomonari; Balastegui, Andreu; Sánchez, Antonio M; Castell, Joan V

2016-01-01

Marine invertebrates potentially represent a group of species whose ecology may be influenced by artificial noise. Exposure to anthropogenic sound sources could have a direct consequence on the functionality and sensitivity of their sensory organs, the statocysts, which are responsible for their equilibrium and movements in the water column. The availability of novel laser Doppler vibrometer techniques has recently opened the possibility of measuring whole body (distance, velocity, and acceleration) vibration as a direct stimulus eliciting statocyst response, offering the scientific community a new level of understanding of the marine invertebrate hearing mechanism.

Calibrated Blade-Element/Momentum Theory Aerodynamic Model of the MARIN Stock Wind Turbine: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goupee, A.; Kimball, R.; de Ridder, E. J.

2015-04-02

In this paper, a calibrated blade-element/momentum theory aerodynamic model of the MARIN stock wind turbine is developed and documented. The model is created using open-source software and calibrated to closely emulate experimental data obtained by the DeepCwind Consortium using a genetic algorithm optimization routine. The provided model will be useful for those interested in validating interested in validating floating wind turbine numerical simulators that rely on experiments utilizing the MARIN stock wind turbine—for example, the International Energy Agency Wind Task 30’s Offshore Code Comparison Collaboration Continued, with Correlation project.

The effect of wind mixing on the vertical distribution of buoyant plastic debris

NASA Astrophysics Data System (ADS)

Kukulka, T.; Proskurowski, G.; Morét-Ferguson, S.; Meyer, D. W.; Law, K. L.

2012-04-01

Micro-plastic marine debris is widely distributed in vast regions of the subtropical gyres and has emerged as a major open ocean pollutant. The fate and transport of plastic marine debris is governed by poorly understood geophysical processes, such as ocean mixing within the surface boundary layer. Based on profile observations and a one-dimensional column model, we demonstrate that plastic debris is vertically distributed within the upper water column due to wind-driven mixing. These results suggest that total oceanic plastics concentrations are significantly underestimated by traditional surface measurements, requiring a reinterpretation of existing plastic marine debris data sets. A geophysical approach must be taken in order to properly quantify and manage this form of marine pollution.

Postglacial trends of hillslope development in two glacially formed mountain valleys in western Norway

NASA Astrophysics Data System (ADS)

Laute, K.; Beylich, A. A.

2012-04-01

Although rockfall talus slopes occur in all regions where rock weathering products accumulate beneath rock faces and cliffs, they are particularly common in glacially formed mountain landscapes. The retreat of glacier ice from glaciated valleys which have probably experienced oversteepening of rock slopes by glacial erosion causes paraglacial destabilization of the valley sidewalls related to stress-relief, unloading, frost weathering and / or degradation of mountain permafrost. Large areas of the Norwegian fjord landscapes are occupied by hillslopes which are owned by the influences of the glacial inheritance of the last glacial maximum (LGM). This study focuses on Postglacial trends of hillslope development in two glacially formed mountain valleys in western Norway (Erdalen and Bødalen). The research is part of a doctoral thesis, which is integrated in the Norwegian Research Council (NFR) funded SedyMONT-Norway project within the ESF TOPO-EUROPE SedyMONT (Timescales of sediment dynamics, climate and topographic change in mountain landscapes) Programme. The main aspects addressed in this study are: (i) the spatio-temporal variability of denudative slope processes over the Holocene and (ii) the Postglacial modification of the glacial relief. The applied process-based approach includes detailed geomorphological fieldmapping combined with terrestrial laser scans (LIDAR) of slope deposits in order to identify possible deposition processes and their spatial variability, relative dating techniques (tree rings and lichens) to analyze subrecent temporal variations, detailed surface mapping with additional geophysical subsurface investigations to estimated regolith thicknesses as well as CIR- and orthophoto delineation combined with GIS and DEM computing for calculating estimates of average valley-wide rockwall retreat rates. Results show Holocene rockwall retreat rates for the two valleys which are in a comparable range with other estimates of rockwall retreat rates in other cold mountain environments worldwide. Further on the results indicate probably higher accumulation rates of slope deposits mainly throughout an enhanced rockfall activity shortly after the glacier retreat (at about 10.000 yr BP) as compared to subrecent and contemporary rates. The overall tendency of landscape development is a Postglacial modification of the defined U-shaped valley morphometry (valley widening) throughout rockwall retreat and connected accumulation of debris material beneath these rockwalls. Active fluvial material removal at the base of slopes is almost negligible due to a very limited hillslope-channel coupling in both valleys. So far, the glacially sculptured relief has not adapted to the denudative surface processes occurring under recent environmental conditions.

Sedimentary framework of Penobscot Bay, Maine

USGS Publications Warehouse

Knebel, Harley J.; Scanlon, Kathryn M.

1985-01-01

Analyses of seismic-reflection profiles, along with previously collected sediment samples and geologic information from surrounding coastal areas, outline the characteristics, distribution, and history of the strata that accumulated within Penobscot Bay, Maine, during the complex period of glaciation, crustal movement, and sea-level change since late Wisconsinan time. Sediments that overlie the rugged, glacially eroded surface of Paleozoic bedrock range in thickness from near zero to more than 50 m and consist of four distinct units.Massive to partly stratified, coarse-grained drift forms thin (< 15 m) isolated patches along the walls and floors of bedrock troughs and constitutes a thick (up to 30 m), hummocky end moraine in the central part of the bay. The drift was deposited by the last ice sheet between 12,700 and 13,500 years ago during deglaciation and coastal submergence (due to crustal depression).Well-stratified, fine-grained glaciomarine deposits are concentrated in bedrock depressions beneath the main passages of the bay. During the period of ice retreat and marine submergence, these sediments settled to the sea floor, draped the irregular underlying surface of bedrock or drift, and accumulated without disturbance by physical or biologic processes.Heterogeneous fluvial deposits fill ancestral channels of the Penobscot River beneath the head of the bay. The channels were incised during a −40 m postglacial low stand of sea level (due to crustal rebound) and later were filled as base level was increased during Holocene time.Muddy marine sediments, which are homogeneous to weakly stratified and rich in organic matter, blanket older deposits within bathymetric depressions in the middle and lower reaches of the bay and cover a pronounced, gently dipping, erosional unconformity in the upper reach. These sediments were deposited during the Holocene transgression as sea level approached its present position and the bay became deeper.Late Wisconsinan and Holocene sedimentation in Penobscot Bay has smoothed the sea floor, but it has not completely obscured the ice-sculptured bedrock topography.

Infilling and flooding of the Mekong River incised valley during deglacial sea-level rise

NASA Astrophysics Data System (ADS)

Tjallingii, Rik; Stattegger, Karl; Wetzel, Andreas; Van Phach, Phung

2010-06-01

The abrupt transition from fluvial to marine deposition of incised-valley-fill sediments retrieved from the southeast Vietnamese shelf, accurately records the postglacial transgression after 14 ka before present (BP). Valley-filling sediments consist of fluvial mud, whereas sedimentation after the transgression is characterized by shallow-marine carbonate sands. This change in sediment composition is accurately marked in high-resolution X-ray fluorescence (XRF) core scanning records. Rapid aggradation of fluvial sediments at the river mouth nearly completely filled the Mekong incised valley prior to flooding. However, accumulation rates strongly reduced in the valley after the river-mouth system flooded and stepped back. This also affected the sediment supply to deeper parts of the southeast Vietnamese shelf. Comparison of the Mekong valley-filling with the East Asian sea-level history of sub- and inter-tidal sediment records shows that the transgressive surface preserved in the incised-valley-fill records is a robust sea-level indicator. The valley was nearly completely filled with fluvial sediments between 13.0 and 9.5 ka BP when sea-level rose rather constantly with approximately 10 mm/yr, as indicated by the East Asian sea-level record. At shallower parts of the shelf, significant sediment reworking and the establishment of estuarine conditions at the final stage of infilling complicates accurate dating of the transgressive surface. Nevertheless, incised-valley-fill records and land-based drill sites indicate a vast and rapid flooding of the shelf from the location of the modern Vietnamese coastline to the Cambodian lowlands between 9.5 ka and 8.5 ka BP. Fast flooding of this part of the shelf is related with the low shelf gradient and a strong acceleration of the East Asian sea-level rise from 34 to 9 meter below modern sea level (mbsl) corresponding to the sea-level jump of melt water pulse (MWP) 1C.

Holocene environmental and parasequence development of the St. Jones Estuary, Delaware (USA): Foraminiferal proxies of natural climatic and anthropogenic change

USGS Publications Warehouse

Leorri, E.; Martin, R.; McLaughlin, P.

2006-01-01

The benthic foraminiferal record of marshes located along western Delaware Bay (St. Jones Estuary, USA) reflects the response of estuaries to sea-level and paleoclimate change during the Holocene. System tracts are recognized and within them parasequences based on sedimentological and foraminiferal assemblages identification. The parasequences defined by foraminiferal assemblages appear correlative with rapid Holocene climate changes that are of worldwide significance: 6000-5000, 4200-3800, 3500-2500, 1200-1000, and 600??cal years BP. Following postglacial sea-level rise, modern subestuaries and marshes in the region began to develop between 6000 and 4000??years BP, depending on their proximity to the mouth of Delaware Bay and coastal geomorphology. Initial sediments were fluvial in origin, with freshwater marshes established around 4000??years BP. The subsequent sea-level transgression occurred sufficiently slowly that freshwater marshes alternated with salt marshes at the same sites to around 3000??years BP. Locally another two transgressions are identified at 1800 and 1000??years BP respectively. Marine influence increased in the estuaries until 600??years BP (Little Ice Age), when regression occurred. Sea-level began to rise again during the mid-19th Century at the end of the Little Ice Age, when marshes became established. The presence of a sand lens in the upper and middle estuary and the reduction in the number of tests in the top samples in cores from the same area also suggest an anthropogenic influence. The estuary infill resulted in a sharp transgressive sequence, represented by salt marsh foraminiferal assemblages in the upper part of the cores. The increase in marsh foraminifera in both areas suggests an increase in marine influence that might be due to the transgression beginning at the end of the Little Ice Age about 150-180??years ago coupled with anthropogenic straightening of the channel in 1913. ?? 2006 Elsevier B.V. All rights reserved.

The vegetation history of the last glacial-interglacial cycle in eastern New South Wales, Australia

NASA Astrophysics Data System (ADS)

Williams, N. J.; Harle, K. J.; Gale, S. J.; Heijnis, H.

2006-10-01

We present a reconstruction of the vegetation history of the last glacial-interglacial cycle (ca. 75 k cal. yr BP-present) at Redhead Lagoon, an enclosed lake basin in coastal, eastern New South Wales, Australia. The sequence of vegetation change at the site is broadly comparable with the pattern of climatically induced changes observed in many other pollen records in southeast Australia. Open woodland-herbland and woodland-forest communities correspond with glacial and interglacial periods respectively, with an additional change towards a more open understorey vegetation assemblage over the last 40 000 yr. The driest conditions appear to have occurred during the height of the last glacial (some time between 30 and 20 k cal. yr BP). This is consistent with other records from southeast Australia, and provides support for a poleward shift in the subtropical anticyclone belt and, less certainly, for the thesis that the Southern Hemisphere westerlies intensified during this period. In marked contrast to most sites in southeast Australia, Casuarinaceae dominates the pollen record through the height of the last glacial period and into the Holocene. The postglacial climatic amelioration is accompanied by the general reappearance of tree pollen in the record, by the disappearance of several open and disturbed environment indicator taxa, by increases in organic sediment deposition and pollen taxon diversity, and by higher water balances. While climate appears to have been the major control on patterns of vegetation change at this site throughout most of the last glacial-interglacial cycle, changes in depositional environment and hydrology have also played a role. Significantly, substantial increases in the rate and magnitude of many indicators of environmental disturbance since European settlement suggest that humans are now the most important mechanism for environmental change. Copyright

Identifying Meteorological Controls on Open and Closed Mesoscale Cellular Convection Associated with Marine Cold Air Outbreaks

NASA Astrophysics Data System (ADS)

McCoy, Isabel L.; Wood, Robert; Fletcher, Jennifer K.

2017-11-01

Mesoscale cellular convective (MCC) clouds occur in large-scale patterns over the ocean and have important radiative effects on the climate system. An examination of time-varying meteorological conditions associated with satellite-observed open and closed MCC clouds is conducted to illustrate the influence of large-scale meteorological conditions. Marine cold air outbreaks (MCAO) influence the development of open MCC clouds and the transition from closed to open MCC clouds. MCC neural network classifications on Moderate Resolution Imaging Spectroradiometer (MODIS) data for 2008 are collocated with Clouds and the Earth's Radiant Energy System (CERES) data and ERA-Interim reanalysis to determine the radiative effects of MCC clouds and their thermodynamic environments. Closed MCC clouds are found to have much higher albedo on average than open MCC clouds for the same cloud fraction. Three meteorological control metrics are tested: sea-air temperature difference (ΔT), estimated inversion strength (EIS), and a MCAO index (M). These predictive metrics illustrate the importance of atmospheric surface forcing and static stability for open and closed MCC cloud formation. Predictive sigmoidal relations are found between M and MCC cloud frequency globally and regionally: negative for closed MCC cloud and positive for open MCC cloud. The open MCC cloud seasonal cycle is well correlated with M, while the seasonality of closed MCC clouds is well correlated with M in the midlatitudes and EIS in the tropics and subtropics. M is found to best distinguish open and closed MCC clouds on average over shorter time scales. The possibility of a MCC cloud feedback is discussed.

The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications

USGS Publications Warehouse

Sala, Enric; Ballesteros, Enric; Dendrinos, Panagiotis; Di Franco, Antonio; Ferretti, Francesco; Foley, David; Fraschetti, Simonetta; Friedlander, Alan M.; Garrabou, Joaquim; Guclusoy, Harun; Guidetti, Paolo; Halpern, Benjamin S.; Hereu, Bernat; Karamanlidis, Alexandros A.; Kizilkaya, Zafer; Macpherson, Enrique; Mangialajo, Luisa; Mariani, Simone; Micheli, Fiorenza; Pais, Antonio; Riser, Kristin; Rosenberg, Andrew A.; Sales, Marta; Selkoe, Kimberly A.; Starr, Rick; Tomas, Fiona; Zabala, Mikel

2012-01-01

Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m-2). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.

The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications.

PubMed

Sala, Enric; Ballesteros, Enric; Dendrinos, Panagiotis; Di Franco, Antonio; Ferretti, Francesco; Foley, David; Fraschetti, Simonetta; Friedlander, Alan; Garrabou, Joaquim; Güçlüsoy, Harun; Guidetti, Paolo; Halpern, Benjamin S; Hereu, Bernat; Karamanlidis, Alexandros A; Kizilkaya, Zafer; Macpherson, Enrique; Mangialajo, Luisa; Mariani, Simone; Micheli, Fiorenza; Pais, Antonio; Riser, Kristin; Rosenberg, Andrew A; Sales, Marta; Selkoe, Kimberly A; Starr, Rick; Tomas, Fiona; Zabala, Mikel

2012-01-01

Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m(-2)). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.

Mansouramycin C kills cancer cells through reactive oxygen species production mediated by opening of mitochondrial permeability transition pore

PubMed Central

Kuang, Shan; Liu, Ge; Cao, Ruobing; Zhang, Linlin; Yu, Qiang; Sun, Chaomin

2017-01-01

Cancer is one of the deadliest diseases in the world and the search for novel anticancer agents is urgently required. Marine-derived isoquinolinequinones have exhibited promising anticancer activities. However, the exact mechanisms of cytotoxic activities of these isoquinolinequinones are poorly characterized. In this study, we investigated the anticancer effects and molecular mechanisms of mansouramycin C (Mm C), a cytotoxic isoquinolinequinone isolated from a marine streptomycete. We demonstrated that Mm C preferentially killed cancer cells and the cytotoxic effects were mediated by reactive oxygen species (ROS) generation. Mass spectrometry based proteomic analysis of Mm C-treated A549 cells revealed that many ROS-related proteins were differentially expressed. Proteomic-profiling after Mm C treatment identified oxidative phosphorylation as the most significant changes in pathways. Analysis also revealed extensive defects in mitochondrial structure and function. Furthermore, we disclosed that Mm C-induced ROS generation was caused by opening of mitochondrial permeability transition pore. Notably, Mm C synergized with sorafenib to induce cell death in A549 cells. Hence, we propose that the marine-derived natural compound Mm C is a potent inducer of the mitochondrial permeability transition and a promising anticancer drug candidate. Moreover, molecular mechanisms of Mm C shed new light on the understanding of the cytotoxic mechanisms of marine-derived isoquinolinequiones. PMID:29262621

Managing ocean information in the digital era--events in Canada open questions about the role of marine science libraries.

PubMed

Wells, Peter G

2014-06-15

Information is the foundation of evidence-based policies for effective marine environmental protection and conservation. In Canada, the cutback of marine science libraries introduces key questions about the role of such institutions and the management of ocean information in the digital age. How vital are such libraries in the mission of studying and protecting the oceans? What is the fate and value of the massive grey literature holdings, including archival materials, much of which is not in digital form but which often contains vital data? How important is this literature generally in the marine environmental sciences? Are we likely to forget the history of the marine pollution field if our digital focus eclipses the need for and access to comprehensive collections and skilled information specialists? This paper explores these and other questions against the backdrop of unprecedented changes in the federal libraries, marine environmental science and legislation in Canada. Copyright © 2014 The Author. Published by Elsevier Ltd.. All rights reserved.

Polysaccharides from the Marine Environment with Pharmacological, Cosmeceutical and Nutraceutical Potential.

PubMed

Ruocco, Nadia; Costantini, Susan; Guariniello, Stefano; Costantini, Maria

2016-04-27

Carbohydrates, also called saccharides, are molecules composed of carbon, hydrogen, and oxygen. They are the most abundant biomolecules and essential components of many natural products and have attracted the attention of researchers because of their numerous human health benefits. Among carbohydrates the polysaccharides represent some of the most abundant bioactive substances in marine organisms. In fact, many marine macro- and microorganisms are good resources of carbohydrates with diverse applications due to their biofunctional properties. By acting on cell proliferation and cycle, and by modulating different metabolic pathways, marine polysaccharides (including mainly chitin, chitosan, fucoidan, carrageenan and alginate) also have numerous pharmaceutical activities, such as antioxidative, antibacterial, antiviral, immuno-stimulatory, anticoagulant and anticancer effects. Moreover, these polysaccharides have many general beneficial effects for human health, and have therefore been developed into potential cosmeceuticals and nutraceuticals. In this review we describe current advances in the development of marine polysaccharides for nutraceutical, cosmeceutical and pharmacological applications. Research in this field is opening new doors for harnessing the potential of marine natural products.

Vegetation responses to interglacial warming in the Arctic: examples from Lake El'gygytgyn, Far East Russian Arctic

NASA Astrophysics Data System (ADS)

Lozhkin, A. V.; Anderson, P. M.

2013-06-01

Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea-Larix-Betula-Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial-interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula-Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios.

Molluscan and Foraminiferan Paleoecological Reconstructions of Extreme Post-Glacial Seafloor Environments of the California Borderland

NASA Astrophysics Data System (ADS)

Moffitt, S. E.; Hill, T. M.; Kroeker, K.; Roopnarine, P. D.; Kennett, J.

2014-12-01

We have reconstructed paleoecological and climatic change in a Late Quaternary (16.1-3.4 ka) sediment core from the California margin (418 meters below sea level) of Santa Barbara Basin using quantitative analyses of Molluscan and Foraminiferan microfossils. This archive represents the first record of marine metazoan community ecology, and a comparison to a well-established biotic proxy (Foraminifera), through the climatic and oceanographic events of the most recent deglaciation. The high-resolution seafloor archive reveals strong coupling between orbital and millennial climatic episodes and the structure of shallow ocean ecosystems. Changes in the density and diversity of molluscs and foraminifera exhibit clear associations with climatic events that mark the deglacial episode, including rapid expansions and contractions of the Oxygen Minimum Zone and development of chemosynthetic bacterial mat communities. Molluscans occur discontinuously in only 28% of the sediment sequence, whereas foraminifera occur throughout. Multivariate statistical analyses of the community ecology assist with the interpretations of the multi-species paleoecological data and of processes that caused the variability. A surprising dominance of molluscan extremophiles (sulfidic Astrys permodesta and hypoxic Lucinoma aequizonatum) during cool, well oxygenated intervals reveals how such forms can thrive during inferred brief ephemeral extreme events. Hydrographic variability and bottom water flow, as well as the growth of benthic bacterial communities, determine where such extremophile communities dominate.

Lake Yoa (Northern Chad): A Seasonal Footprint of 10,500 Years of Climate Change in the Sahara

NASA Astrophysics Data System (ADS)

Kroepelin, S.; Cocquyt, C.; Darius, F.; Dinies, M.; Francus, P.; Just, J.; Karls, J.; Kuper, J.; Lézine, A. M.; Mallaye, B.; Melles, M.; Sylvestre, F.; Viehberg, F. A.; Wennrich, V.

2016-12-01

We present Africa's most complete Holocene climate record in a long awaited breakthrough that few would have expected in one of the driest and most remote parts of the Sahara, the planet's major hot desert. A 16 m thick continuous sequence of seasonally laminated (varved) deposits at the bottom of a now fully groundwater-supported oasis lake at Ounianga Kebir in northern Chad extends our earlier 6,000 year record published in 2008 back to the onset of postglacial humid conditions 10,500 years ago in unrivalled detail. Main results indicate a rather slow regreening in northern Africa after 100,000 years of apparently continuous late Pleistocene aridity; precisely define the severe environmental impact of global climate events such as the 8,200 BP North Atlantic cooling even in hypercontinental positions far away from the oceans; and corroborate the gradual termination of the last "Green Sahara" period over millennia. Lake Yoa's varve count-controlled age model also shows the high error potential of the existing 14C chronology from bulk carbonate-dated paleolacustrine archives elsewhere in the Sahara and provides a basis for its correction. The new terrestrial multiproxy data set discloses agreements and discrepancies to marine and ice core data, and numeric climate models. As a natural analogue, it helps to foresee how North Africa's climate and environments might evolve due to anthropogenic global warming.

Collapse of polar ice sheets during the stage 11 interglacial.

PubMed

Raymo, Maureen E; Mitrovica, Jerry X

2012-03-14

Contentious observations of Pleistocene shoreline features on the tectonically stable islands of Bermuda and the Bahamas have suggested that sea level about 400,000 years ago was more than 20 metres higher than it is today. Geochronologic and geomorphic evidence indicates that these features formed during interglacial marine isotope stage (MIS) 11, an unusually long interval of warmth during the ice age. Previous work has advanced two divergent hypotheses for these shoreline features: first, significant melting of the East Antarctic Ice Sheet, in addition to the collapse of the West Antarctic Ice Sheet and the Greenland Ice Sheet; or second, emplacement by a mega-tsunami during MIS 11 (ref. 4, 5). Here we show that the elevations of these features are corrected downwards by ∼10 metres when we account for post-glacial crustal subsidence of these sites over the course of the anomalously long interglacial. On the basis of this correction, we estimate that eustatic sea level rose to ∼6-13 m above the present-day value in the second half of MIS 11. This suggests that both the Greenland Ice Sheet and the West Antarctic Ice Sheet collapsed during the protracted warm period while changes in the volume of the East Antarctic Ice Sheet were relatively minor, thereby resolving the long-standing controversy over the stability of the East Antarctic Ice Sheet during MIS 11.

Archaea in Organic-Lean and Organic-Rich Marine Subsurface Sediments: An Environmental Gradient Reflected in Distinct Phylogenetic Lineages

PubMed Central

Durbin, Alan M.; Teske, Andreas

2012-01-01

Examining the patterns of archaeal diversity in little-explored organic-lean marine subsurface sediments presents an opportunity to study the association of phylogenetic affiliation and habitat preference in uncultured marine Archaea. Here we have compiled and re-analyzed published archaeal 16S rRNA clone library datasets across a spectrum of sediment trophic states characterized by a wide range of terminal electron-accepting processes. Our results show that organic-lean marine sediments in deep marine basins and oligotrophic open ocean locations are inhabited by distinct lineages of archaea that are not found in the more frequently studied, organic-rich continental margin sediments. We hypothesize that different combinations of electron donor and acceptor concentrations along the organic-rich/organic-lean spectrum result in distinct archaeal communities, and propose an integrated classification of habitat characteristics and archaeal community structure. PMID:22666218

Marine Microbiological Enzymes: Studies with Multiple Strategies and Prospects.

PubMed

Wang, Yan; Song, Qinghao; Zhang, Xiao-Hua

2016-09-22

Marine microorganisms produce a series of promising enzymes that have been widely used or are potentially valuable for our daily life. Both classic and newly developed biochemistry technologies have been broadly used to study marine and terrestrial microbiological enzymes. In this brief review, we provide a research update and prospects regarding regulatory mechanisms and related strategies of acyl-homoserine lactones (AHL) lactonase, which is an important but largely unexplored enzyme. We also detail the status and catalytic mechanism of the main types of polysaccharide-degrading enzymes that broadly exist among marine microorganisms but have been poorly explored. In order to facilitate understanding, the regulatory and synthetic biology strategies of terrestrial microorganisms are also mentioned in comparison. We anticipate that this review will provide an outline of multiple strategies for promising marine microbial enzymes and open new avenues for the exploration, engineering and application of various enzymes.

Measurement of sub-parts-per-billion levels of carbonyl compounds in marine air by a simple cartridge trapping procedure followed by liquid chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xianliang, Zhou; Mopper, K.

1990-10-01

Carbonyl compounds in clean marine air were trapped onto 2,4-dinitrophenylhydrazine- (DNPH-) coated cartridges, and their hydrazone derivatives were separated by HPLC and detected by UV absorbance. More than 20 carbonyl compounds were isolated from marine air with >92% collection efficiency. The technique employs a highly effective reagent purification procedure, which results in much lower blanks compared to previously reported trapping techniques for carbonyl compounds. Blanks were routinely <0.07 ppb for formaldehyde and acetone and <0.02 ppb for the others. Humidity and reactive gases have no detectable effect on collection efficiencies. Carbonyl-DNPH derivatives eluted from the cartridges are stable in acetonitrilemore » for at least 2 weeks, which facilitates field studies. Several previously undetected unknown carbonyl compounds were found in marine air by this technique. Typical results for open ocean and coastal marine air are shown.« less

Experimental evolution gone wild.

PubMed

Scheinin, M; Riebesell, U; Rynearson, T A; Lohbeck, K T; Collins, S

2015-05-06

Because of their large population sizes and rapid cell division rates, marine microbes have, or can generate, ample variation to fuel evolution over a few weeks or months, and subsequently have the potential to evolve in response to global change. Here we measure evolution in the marine diatom Skeletonema marinoi evolved in a natural plankton community in CO2-enriched mesocosms deployed in situ. Mesocosm enclosures are typically used to study how the species composition and biogeochemistry of marine communities respond to environmental shifts, but have not been used for experimental evolution to date. Using this approach, we detect a large evolutionary response to CO2 enrichment in a focal marine diatom, where population growth rate increased by 1.3-fold in high CO2-evolved lineages. This study opens an exciting new possibility of carrying out in situ evolution experiments to understand how marine microbial communities evolve in response to environmental change.

Influence of marine current on vertical migration of Pb in marine bay

NASA Astrophysics Data System (ADS)

Yu, Chen; Hong, Ai; Danfeng, Yang; Huijuan, Zhao; Dongfang, Yang

2018-02-01

This paper analyzed that vertical migration of Pb contents waters in Jiaozhou Bay, and revealed the influence of marine current on vertical migration process. Results showed that Pb contents in bottom waters of Jiaozhou Bay in April and July 1988 were 1.49-18.53 μg L-1 and 12.68/-27.64 μg L-1, respectively. The pollution level of Pb in bottom waters was moderate to heavy, and were showing temporal variations and spatial heterogeneity. The vertical migration process of Pb in April 1988 included a drifting process from the southwest to the north by means of the marine current was rapid in this region. The vertical migration process of Pb in July 1988 in the open waters included no drifting process since the flow rate of marine current was relative low in this region. The vertical migration process of Pb was jointly determined by vertical water’s effect, source input and water exchange, and the influence of marine current on the vertical migration of Pb in marine bay was significant.

75 FR 13731 - National Marine Fisheries Service, Pacific Fishery Management Council (Pacific Council); April 9...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-23

... through Thursday, April 15, 2010. All meetings are open to the public, except a closed session will be... Agenda B. Open Comment Period 1. Comments on Non-Agenda Items C. Enforcement Issues 1. U.S. Coast Guard... OF ANCILLARY MEETINGS Friday, April 9, 2010 Ad Hoc Regulatory Deeming Committee 8 am Groundfish...

Monitoring Mediterranean marine pollution using remote sensing and hydrodynamic modelling

NASA Astrophysics Data System (ADS)

La Loggia, Goffredo; Capodici, Fulvio; Ciraolo, Giuseppe; Drago, Aldo; Maltese, Antonino

2011-11-01

Human activities contaminate both coastal areas and open seas, even though impacts are different in terms of pollutants, ecosystems and recovery time. In particular, Mediterranean offshore pollution is mainly related to maritime transport of oil, accounting for 25% of the global maritime traffic and, during the last 25 years, for nearly 7% of the world oil accidents, thus causing serious biological impacts on both open sea and coastal zone habitats. This paper provides a general review of maritime pollution monitoring using integrated approaches of remote sensing and hydrodynamic modeling; focusing on the main results of the MAPRES (Marine pollution monitoring and detection by aerial surveillance and satellite images) research project on the synergistic use of remote sensing, forecasting, cleanup measures and environmental consequences. The paper also investigates techniques of oil spill detection using SAR images, presenting the first results of "Monitoring of marine pollution due to oil slick", a COSMO-SkyMed funded research project where X-band SAR constellation images provided by the Italian Space Agency are used. Finally, the prospect of using real time observations of marine surface conditions is presented through CALYPSO project (CALYPSO-HF Radar Monitoring System and Response against Marine Oil Spills in the Malta Channel), partly financed by the EU under the Operational Programme Italia-Malta 2007-2013. The project concerns the setting up of a permanent and fully operational HF radar observing system, capable of recording surface currents (in real-time with hourly updates) in the stretch of sea between Malta and Sicily. A combined use of collected data and numerical models, aims to optimize intervention and response in the case of marine oil spills.

Mapping the future expansion of Arctic open water

NASA Astrophysics Data System (ADS)

Barnhart, Katherine R.; Miller, Christopher R.; Overeem, Irina; Kay, Jennifer E.

2016-03-01

Sea ice impacts most of the Arctic environment, from ocean circulation and marine ecosystems to animal migration and marine transportation. Sea ice has thinned and decreased in age over the observational record. Ice extent has decreased. Reduced ice cover has warmed the surface ocean, accelerated coastal erosion and impacted biological productivity. Declines in Arctic sea-ice extent cannot be explained by internal climate variability alone and can be attributed to anthropogenic effects. However, extent is a poor measure of ice decline at specific locations as it integrates over the entire Arctic basin and thus contains no spatial information. The open water season, in contrast, is a metric that represents the duration of open water over a year at an individual location. Here we present maps of the open water season over the period 1920-2100 using daily output from a 30-member initial-condition ensemble of business-as-usual climate simulations that characterize the expansion of Arctic open water, determine when the open water season will move away from pre-industrial conditions (`shift’ time) and identify when human forcing will take the Arctic sea-ice system outside its normal bounds (`emergence’ time). The majority of the Arctic nearshore regions began shifting in 1990 and will begin leaving the range of internal variability in 2040. Models suggest that ice will cover coastal regions for only half of the year by 2070.

Global estimation of areas with suitable environmental conditions for mariculture species

PubMed Central

Reygondeau, Gabriel; Wabnitz, Colette C. C.; Troell, Max; Cheung, William W. L.

2018-01-01

Aquaculture has grown rapidly over the last three decades expanding at an average annual growth rate of 5.8% (2005–2014), down from 8.8% achieved between 1980 and 2010. The sector now produces 44% of total food fish production. Increasing demand and consumption from a growing global population are driving further expansion of both inland and marine aquaculture (i.e., mariculture, including marine species farmed on land). However, the growth of mariculture is dependent on the availability of suitable farming areas for new facilities, particularly for open farming practices that rely on the natural oceanic environmental parameters such as temperature, oxygen, chlorophyll etc. In this study, we estimated the marine areas within the exclusive economic zones of all countries that were suitable for potential open ocean mariculture activities. To this end, we quantify the environmental niche and inferred the global habitat suitability index (HSI) of the 102 most farmed marine species using four species distribution models. The average weighted HSI across the four models suggests that 72,000,000 km2 of ocean are to be environmentally suitable to farm one or more species. About 92% of the predicted area (66,000,000 km2) is environmentally suitable for farming finfish, 43% (31,000,000 km2) for molluscs and 54% (39,000,000 km2) for crustaceans. These predictions do not consider technological feasibility that can limit crustaceans farming in open waters. Suitable mariculture areas along the Atlantic coast of South America and West Africa appear to be most under-utilized for farming. Our results suggest that factors other than environmental considerations such as the lack of socio-economic and technological capacity, as well as aqua feed supply are currently limiting the potential for mariculture expansion in many areas. PMID:29357374

An original mode of symbiosis in open ocean plankton.

PubMed

Decelle, Johan; Probert, Ian; Bittner, Lucie; Desdevises, Yves; Colin, Sébastien; de Vargas, Colomban; Galí, Martí; Simó, Rafel; Not, Fabrice

2012-10-30

Symbiotic relationships are widespread in nature and are fundamental for ecosystem functioning and the evolution of biodiversity. In marine environments, photosymbiosis with microalgae is best known for sustaining benthic coral reef ecosystems. Despite the importance of oceanic microbiota in global ecology and biogeochemical cycles, symbioses are poorly characterized in open ocean plankton. Here, we describe a widespread symbiotic association between Acantharia biomineralizing microorganisms that are abundant grazers in plankton communities, and members of the haptophyte genus Phaeocystis that are cosmopolitan bloom-forming microalgae. Cophylogenetic analyses demonstrate that symbiont biogeography, rather than host taxonomy, is the main determinant of the association. Molecular dating places the origin of this photosymbiosis in the Jurassic (ca. 175 Mya), a period of accentuated marine oligotrophy. Measurements of intracellular dimethylated sulfur indicate that the host likely profits from antioxidant protection provided by the symbionts as an adaptation to life in transparent oligotrophic surface waters. In contrast to terrestrial and marine symbioses characterized to date, the symbiont reported in this association is extremely abundant and ecologically active in its free-living phase. In the vast and barren open ocean, partnership with photosymbionts that have extensive free-living populations is likely an advantageous strategy for hosts that rely on such interactions. Discovery of the Acantharia-Phaeocystis association contrasts with the widely held view that symbionts are specialized organisms that are rare and ecologically passive outside the host.

Complete-fosmid and fosmid-end sequences reveal frequent horizontal gene transfers in marine uncultured planktonic archaea

PubMed Central

Brochier-Armanet, Céline; Deschamps, Philippe; López-García, Purificación; Zivanovic, Yvan; Rodríguez-Valera, Francisco; Moreira, David

2011-01-01

The extent of horizontal gene transfer (HGT) among marine pelagic prokaryotes and the role that HGT may have played in their adaptation to this particular environment remain open questions. This is partly due to the paucity of cultured species and genomic information for many widespread groups of marine bacteria and archaea. Molecular studies have revealed a large diversity and relative abundance of marine planktonic archaea, in particular of Thaumarchaeota (also known as group I Crenarchaeota) and Euryarchaeota of groups II and III, but only one species (the thaumarchaeote Candidatus Nitrosopumilus maritimus) has been isolated in pure culture so far. Therefore, metagenomics remains the most powerful approach to study these environmental groups. To investigate the impact of HGT in marine archaea, we carried out detailed phylogenetic analyses of all open reading frames of 21 archaeal 16S rRNA gene-containing fosmids and, to extend our analysis to other genomic regions, also of fosmid-end sequences of 12 774 fosmids from three different deep-sea locations (South Atlantic and Adriatic Sea at 1000 m depth, and Ionian Sea at 3000 m depth). We found high HGT rates in both marine planktonic Thaumarchaeota and Euryarchaeota, with remarkable converging values estimated from complete-fosmid and fosmid-end sequence analysis (25 and 21% of the genes, respectively). Most HGTs came from bacterial donors (mainly from Proteobacteria, Firmicutes and Chloroflexi) but also from other archaea and eukaryotes. Phylogenetic analyses showed that in most cases HGTs are shared by several representatives of the studied groups, implying that they are ancient and have been conserved over relatively long evolutionary periods. This, together with the functions carried out by these acquired genes (mostly related to energy metabolism and transport of metabolites across membranes), suggests that HGT has played an important role in the adaptation of these archaea to the cold and nutrient-depleted deep marine environment. PMID:21346789

Testing the limits in a greenhouse ocean: Did low nitrogen availability limit marine productivity during the end-Triassic mass extinction?

NASA Astrophysics Data System (ADS)

Schoepfer, Shane D.; Algeo, Thomas J.; Ward, Peter D.; Williford, Kenneth H.; Haggart, James W.

2016-10-01

The end-Triassic mass extinction has been characterized as a 'greenhouse extinction', related to rapid atmospheric warming and associated changes in ocean circulation and oxygenation. The response of the marine nitrogen cycle to these oceanographic changes, and the extent to which mass extinction intervals represent a deviation in nitrogen cycling from other ice-free 'greenhouse' periods of Earth history, remain poorly understood. The well-studied Kennecott Point section in Haida Gwaii, British Columbia, Canada, was deposited in the open Panthalassic Ocean, and is used here as a test case to better understand changes in the nitrogen cycle and marine productivity from the pre-crisis greenhouse of the Rhaetian to the latest-Rhaetian crisis interval. We estimated marine productivity from the late Norian to the early Hettangian using TOC- and P-based paleoproductivity transform equations, and then compared these estimates to records of sedimentary nitrogen isotopes, redox-sensitive trace elements, and biomarker data. Major negative excursions in δ15N (to ≤ 0 ‰) correspond to periods of depressed marine productivity. During these episodes, the development of a stable pycnocline below the base of the photic zone suppressed vertical mixing and limited N availability in surface waters, leading to low productivity and increased nitrogen fixation, as well as ecological stresses in the photic zone. The subsequent shoaling of euxinic waters into the ocean surface layer was fatal for most Triassic marine fauna, although the introduction of regenerated NH4+ into the photic zone may have allowed phytoplankton productivity to recover. These results indicate that the open-ocean nitrogen cycle was influenced by climatic changes during the latest Triassic, despite having existed in a greenhouse state for over 50 million years previously, and that low N availability limited marine productivity for hundreds of thousands of years during the end-Triassic crisis.

Limits to gene flow in a cosmopolitan marine planktonic diatom.

PubMed

Casteleyn, Griet; Leliaert, Frederik; Backeljau, Thierry; Debeer, Ann-Eline; Kotaki, Yuichi; Rhodes, Lesley; Lundholm, Nina; Sabbe, Koen; Vyverman, Wim

2010-07-20

The role of geographic isolation in marine microbial speciation is hotly debated because of the high dispersal potential and large population sizes of planktonic microorganisms and the apparent lack of strong dispersal barriers in the open sea. Here, we show that gene flow between distant populations of the globally distributed, bloom-forming diatom species Pseudo-nitzschia pungens (clade I) is limited and follows a strong isolation by distance pattern. Furthermore, phylogenetic analysis implies that under appropriate geographic and environmental circumstances, like the pronounced climatic changes in the Pleistocene, population structuring may lead to speciation and hence may play an important role in diversification of marine planktonic microorganisms. A better understanding of the factors that control population structuring is thus essential to reveal the role of allopatric speciation in marine microorganisms.

Marine biomass: New York state site and species study compositional analysis and systems studies. Final report Mar-Dec 81

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makinen, R.W.; Farley, K.M.; Kugler, W.R.

1982-02-26

The primary objective of the Marine Biomass Programs is to provide an optimized, integrated process for producing methane from seaweeds cultivated in the open ocean and to do so at a price which is competitive with that of methane from other sources. The New York State Site and Species Study represents the first evaluation of a site outside of Southern California.

Arctic research vessel design would expand science prospects

NASA Astrophysics Data System (ADS)

Elsner, Robert; Kristensen, Dirk

The U.S. polar marine science community has long declared the need for an arctic research vessel dedicated to advancing the study of northern ice-dominated seas. Planning for such a vessel began 2 decades ago, but competition for funding has prevented construction. A new design program is underway, and it shows promise of opening up exciting possibilities for new research initiatives in arctic marine science.With its latest design, the Arctic Research Vessel (ARV) has grown to a size and capability that will make it the first U.S. academic research vessel able to provide access to the Arctic Ocean. This ship would open a vast arena for new studies in the least known of the world's seas. These studies promise to rank high in national priority because of the importance of the Arctic Ocean as a source of data relating to global climate change. Other issues that demand attention in the Arctic include its contributions to the world's heat budget, the climate history buried in its sediments, pollution monitoring, and the influence of arctic conditions on marine renewable resources.

Comparative Genomics Analysis of Streptomyces Species Reveals Their Adaptation to the Marine Environment and Their Diversity at the Genomic Level

PubMed Central

Tian, Xinpeng; Zhang, Zhewen; Yang, Tingting; Chen, Meili; Li, Jie; Chen, Fei; Yang, Jin; Li, Wenjie; Zhang, Bing; Zhang, Zhang; Wu, Jiayan; Zhang, Changsheng; Long, Lijuan; Xiao, Jingfa

2016-01-01

Over 200 genomes of streptomycete strains that were isolated from various environments are available from the NCBI. However, little is known about the characteristics that are linked to marine adaptation in marine-derived streptomycetes. The particularity and complexity of the marine environment suggest that marine streptomycetes are genetically diverse. Here, we sequenced nine strains from the Streptomyces genus that were isolated from different longitudes, latitudes, and depths of the South China Sea. Then we compared these strains to 22 NCBI downloaded streptomycete strains. Thirty-one streptomycete strains are clearly grouped into a marine-derived subgroup and multiple source subgroup-based phylogenetic tree. The phylogenetic analyses have revealed the dynamic process underlying streptomycete genome evolution, and lateral gene transfer is an important driving force during the process. Pan-genomics analyses have revealed that streptomycetes have an open pan-genome, which reflects the diversity of these streptomycetes and guarantees the species a quick and economical response to diverse environments. Functional and comparative genomics analyses indicate that the marine-derived streptomycetes subgroup possesses some common characteristics of marine adaptation. Our findings have expanded our knowledge of how ocean isolates of streptomycete strains adapt to marine environments. The availability of streptomycete genomes from the South China Sea will be beneficial for further analysis on marine streptomycetes and will enrich the South China Sea’s genetic data sources. PMID:27446038

Postglacial vegetation and fire history, eastern Klamath Mountains, California, USA

Treesearch

Jerry A. Mohr; Cathy Whitlock; Carl N. Skinner

2000-01-01

Pollen and high-resolution charcoal data from Bluff Lake and Crater Lake, California, indicate simi lar changes in climate, vegetation and fire history during the last 15 500 years. Pollen data at Bluff Lake suggest that the vegetation betweenc. 15 500 and 13 100 cal. BP consisted of subalpine parkland with scattered Pinus...

Phylogeography, postglacial gene flow, and population history of North American northern goshawks (Accipiter gentilis)

Treesearch

Shelley Bayard de Volo; Richard T. Reynolds; Sarah A. Sonsthagen; Sandra L. Talbot; Michael F. Antolin

2013-01-01

Climate cycling during the Quaternary played a critical role in the diversification of avian lineages in North America, greatly influencing the genetic characteristics of contemporary populations. To test the hypothesis that North American Northern Goshawks (Accipiter gentilis) were historically isolated within multiple Late Pleistocene refugia, we assessed diversity...

The genetic pattern of population threat and loss: a case study of butterflies.

PubMed

Schmitt, T; Hewitt, G M

2004-01-01

Recent decreases in biodiversity in Europe are commonly thought to be due to land use and climate change. However, the genetic diversity of populations is also seen as one essential factor for their fitness. Genetic diversity in species across the continent of Europe has been recognized as being in part a consequence of ice age isolation in southern refugia and postglacial colonization northwards, and these phylogeographical patterns may themselves affect the adaptability of populations. Recent work on butterfly species with different refugia, colonization paths and genetic structures allows this idea to be examined. The 'chalk-hill blue' pattern is one of decreasing genetic diversity from south to north, whereas the 'woodland ringlet' pattern shows greater genetic diversity in eastern than in western lineages. Comparison of population demographic trends in species with these biogeographical patterns reveals higher rates of decrease with lower genetic diversity. This indicates reduced adaptability due to genetic impoverishment as a result of glacial and postglacial range changes. Analysis of phylogeographical pattern may be a useful guide to interpreting demographic trends and in conservation planning.

Regional patterns of postglacial changes in the Palearctic mammalian diversity indicate retreat to Siberian steppes rather than extinction

PubMed Central

Řičánková, Věra Pavelková; Robovský, Jan; Riegert, Jan; Zrzavý, Jan

2015-01-01

We examined the presence of possible Recent refugia of Pleistocene mammalian faunas in Eurasia by analysing regional differences in the mammalian species composition, occurrence and extinction rates between Recent and Last Glacial faunas. Our analyses revealed that most of the widespread Last Glacial species have survived in the central Palearctic continental regions, most prominently in Altai–Sayan (followed by Kazakhstan and East European Plain). The Recent Altai–Sayan and Kazakhstan regions show species compositions very similar to their Pleistocene counterparts. The Palearctic regions have lost 12% of their mammalian species during the last 109,000 years. The major patterns of the postglacial changes in Palearctic mammalian diversity were not extinctions but rather radical shifts of species distribution ranges. Most of the Pleistocene mammalian fauna retreated eastwards, to the central Eurasian steppes, instead of northwards to the Arctic regions, considered Holocene refugia of Pleistocene megafauna. The central Eurasian Altai and Sayan mountains could thus be considered a present-day refugium of the Last Glacial biota, including mammals. PMID:26246136

Convergence of marine megafauna movement patterns in coastal and open oceans.

PubMed

Sequeira, A M M; Rodríguez, J P; Eguíluz, V M; Harcourt, R; Hindell, M; Sims, D W; Duarte, C M; Costa, D P; Fernández-Gracia, J; Ferreira, L C; Hays, G C; Heupel, M R; Meekan, M G; Aven, A; Bailleul, F; Baylis, A M M; Berumen, M L; Braun, C D; Burns, J; Caley, M J; Campbell, R; Carmichael, R H; Clua, E; Einoder, L D; Friedlaender, Ari; Goebel, M E; Goldsworthy, S D; Guinet, C; Gunn, J; Hamer, D; Hammerschlag, N; Hammill, M; Hückstädt, L A; Humphries, N E; Lea, M-A; Lowther, A; Mackay, A; McHuron, E; McKenzie, J; McLeay, L; McMahon, C R; Mengersen, K; Muelbert, M M C; Pagano, A M; Page, B; Queiroz, N; Robinson, P W; Shaffer, S A; Shivji, M; Skomal, G B; Thorrold, S R; Villegas-Amtmann, S; Weise, M; Wells, R; Wetherbee, B; Wiebkin, A; Wienecke, B; Thums, M

2018-03-20

The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals' movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyze a global dataset of ∼2.8 million locations from >2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared with more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal microhabitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise, and declining oxygen content.

The Structure of Mediterranean Rocky Reef Ecosystems across Environmental and Human Gradients, and Conservation Implications

PubMed Central

Sala, Enric; Ballesteros, Enric; Dendrinos, Panagiotis; Di Franco, Antonio; Ferretti, Francesco; Foley, David; Fraschetti, Simonetta; Friedlander, Alan; Garrabou, Joaquim; Güçlüsoy, Harun; Guidetti, Paolo; Halpern, Benjamin S.; Hereu, Bernat; Karamanlidis, Alexandros A.; Kizilkaya, Zafer; Macpherson, Enrique; Mangialajo, Luisa; Mariani, Simone; Micheli, Fiorenza; Pais, Antonio; Riser, Kristin; Rosenberg, Andrew A.; Sales, Marta; Selkoe, Kimberly A.; Starr, Rick; Tomas, Fiona; Zabala, Mikel

2012-01-01

Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m−2). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas. PMID:22393445

40 CFR 49.129 - Rule for limiting emissions of sulfur dioxide.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., incinerator, marine vessel, mobile sources, motor vehicle, nonroad engine, nonroad vehicle, open burning, process source, reference method, refuse, residual fuel oil, solid fuel, stack, standard conditions...

40 CFR 49.129 - Rule for limiting emissions of sulfur dioxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., incinerator, marine vessel, mobile sources, motor vehicle, nonroad engine, nonroad vehicle, open burning, process source, reference method, refuse, residual fuel oil, solid fuel, stack, standard conditions...

Insights on the opening of the Galerian mammal migration pathway from magnetostratigraphy of the Pleistocene marine-continental transition in the Arda River section (northern Italy)

NASA Astrophysics Data System (ADS)

Monesi, Edoardo; Muttoni, Giovanni; Scardia, Giancarlo; Felletti, Fabrizio; Bona, Fabio; Sala, Benedetto; Tremolada, Fabrizio; Francou, Carlo; Raineri, Gianluca

2016-09-01

We investigated the magnetostratigraphy of the Arda River section (northern Italy) where the transition from marine to continental sedimentation occurring in the Po River basin during the Pleistocene is registered. Four magnetic polarity reversals were used to construct an age model of sedimentation aided by marine biostratigraphy and tied to a standard δ18O curve from the literature. The section spans from the Olduvai subchron (1.94-1.78 Ma) across the Jaramillo subchron (1.07-0.99 Ma) up to the Brunhes-Matuyama boundary (0.78 Ma). The onset of continental deposition occurred during marine isotope stage (MIS) 30 at ˜1.04 Ma. An association of Villafranchian and Early Galerian mammals, including Sus strozzii and Ursus dolinensis, has been found in the continental sediments dated to MIS 29-27 (˜0.99 Ma). Above follows a prominent fluvial conglomerate attributed to the first major lowstand of the Pleistocene culminating with MIS 22 at ˜0.9 Ma during the late Early Pleistocene climate turnover (EPT). These and other data from the literature are used to reconstruct the onset of continental deposition in the greater Po basin and shed light on the opening of the migration pathway that brought far-traveled Galerian mammal immigrants to enter Europe for the first time during the EPT.

Occurrence of PPCPs in Pearl River Estuary and South China Sea

NASA Astrophysics Data System (ADS)

Fisch, Kathrin; Waniek, Joanna J.; Schulz-Bull, Detlef E.

2017-04-01

The development of a coastal megacity has put the South China Sea under human induced stress. Pharmaceuticals and personal care products (PPCPs) are ubiquitous contaminants and can be used as anthropogenic indicators for pollution of the marine environment. They enter the marine environment indirectly via waste water or directly due to recreational activities. PPCPs make up a group of different pharmaceuticals such as antibiotic, anti-inflammatories etc. and personal care products such as UV-filters. A mayor concern is the unknown fate and the effect these pollutants on the marine environment and especially its organisms. In some studies it was proven that some of these PPCPs have an endocrine disrupting and/or a subtle chronic effect on aquatic organisms. They are of concern for the health of the marine environment and may have an effect on human health. With our study we could determine the occurrence of PPCPs in the Pearl River estuary and the South China Sea. Salicylic acid (metabolite of acetylsalicylic acid) and octocrylene (UV-filter) were found in the open Sea in low ng/L concentration. Octocrylene is used in sunscreen and as a light stabilizer in paints and polymer-based products. It is of environmental concern because of its potential to be bioaccumulative. In addition to our findings in the open South China Sea, could we detect PPCPs, especially antibiotics, in higher ng/L-concentrations in the Pearl River Estuary.

Floating Classroom Outreach as an Introduction to Ocean Studies

NASA Astrophysics Data System (ADS)

McFadden, M.

2016-02-01

Many children and young adults living within only one hour of the coast never have the opportunity to explore a beach or go out on a boat because of financial challenges or lack of transportation.These types of experiences are the spark that helped many ocean scientists become fascinated with the ocean and later pursue a career related to the ocean. This presentation will discuss a variety of outreach projects and the efficacy of each. Projects vary in age, complexity and cost. These projects include a Beach Clean-Up open to students and their families at a community college organized by a campus volunteer group with a focus on social issues, a Marine Biology and Physical Oceanography class joint floating classroom trip open to college students to introduce non-STEM students to marine science in an exciting setting, and an education outreach trip for 8-12 years old children from the Boys and Girls Club in Newport, RI in collaboration with The International SeaKeepers Society, a non-profit that facilitates ocean research and education by working closely with the yachting community. Emphasis on environmental education in the U.S. has grown considerably over recent years, and the development of unique and innovative approaches to hands-on marine science education are needed to excite students to explore the marine environment and care about environmental stewardship.

The mass balance of soil evolution on late Quaternary marine terraces, northern California

NASA Technical Reports Server (NTRS)

Merritts, Dorothy J.; Chadwick, Oliver A.; Hendricks, David M.; Brimhall, George H.; Lewis, Christopher J.

1992-01-01

Mass-balance interpretation of a soil chronosequence provides a means of quantifying elemental addition, removal, and transformation that occur in soils from a flight of marine terraces in northern California. Six soil profiles that range in age from several to 240,000 yr are developed in unconsolidated, sandy-marine, and eolian parent material deposited on bedrock marine platforms. Soil evolution is dominated by (1) open-system depletion of Si, Ca, Mg, K, and Na; (2) open-system enrichment of P in surface soil horizons; (3) relative immobility of Fe and Al; and (4) transformation of Fe, Si, and Al in the parent material to secondary clay minerals and sesquioxides. Net mass losses of bases and Si are generally uniform with depth and substantial, in some cases approaching 100 percent; however, the rate of loss of each element differs markedly, causing the ranking of each by relative abundance to shift with time. Loss of Si from the sand fraction by dissolution and particle-size diminution, from about 100 percent to less than 35 percent over 240 ky, mirrors a similar gain in the silt and clay size fractions. The Fe originally present in the sand fraction decreases from greater than 80 percent to less than 10 percent, whereas the amount of Fe present in the clay and crystalline oxyhydroxide fractions increases to 25 percent and 70 percent, respectively.

Bryophyte-Cyanobacteria Associations during Primary Succession in Recently Deglaciated Areas of Tierra del Fuego (Chile)

PubMed Central

Arróniz-Crespo, María; Pérez-Ortega, Sergio; De los Ríos, Asunción; Green, T. G. Allan; Ochoa-Hueso, Raúl; Casermeiro, Miguel Ángel; de la Cruz, María Teresa; Pintado, Ana; Palacios, David; Rozzi, Ricardo; Tysklind, Niklas; Sancho, Leopoldo G.

2014-01-01

Bryophyte establishment represents a positive feedback process that enhances soil development in newly exposed terrain. Further, biological nitrogen (N) fixation by cyanobacteria in association with mosses can be an important supply of N to terrestrial ecosystems, however the role of these associations during post-glacial primary succession is not yet fully understood. Here, we analyzed chronosequences in front of two receding glaciers with contrasting climatic conditions (wetter vs drier) at Cordillera Darwin (Tierra del Fuego) and found that most mosses had the capacity to support an epiphytic flora of cyanobacteria and exhibited high rates of N2 fixation. Pioneer moss-cyanobacteria associations showed the highest N2 fixation rates (4.60 and 4.96 µg N g−1 bryo. d−1) very early after glacier retreat (4 and 7 years) which may help accelerate soil development under wetter conditions. In drier climate, N2 fixation on bryophyte-cyanobacteria associations was also high (0.94 and 1.42 µg N g−1 bryo. d−1) but peaked at intermediate-aged sites (26 and 66 years). N2 fixation capacity on bryophytes was primarily driven by epiphytic cyanobacteria abundance rather than community composition. Most liverworts showed low colonization and N2 fixation rates, and mosses did not exhibit consistent differences across life forms and habitat (saxicolous vs terricolous). We also found a clear relationship between cyanobacteria genera and the stages of ecological succession, but no relationship was found with host species identity. Glacier forelands in Tierra del Fuego show fast rates of soil transformation which imply large quantities of N inputs. Our results highlight the potential contribution of bryophyte-cyanobacteria associations to N accumulation during post-glacial primary succession and further describe the factors that drive N2-fixation rates in post-glacial areas with very low N deposition. PMID:24819926

Postglacial dispersal patterns and mitochondrial genetic structure of the Pyrenean desman (Galemys pyrenaicus) in the northwestern region of the Iberian Peninsula.

PubMed

Querejeta, Marina; Fernández-González, Angel; Romero, Rafael; Castresana, Jose

2017-06-01

The genetic structure of small semiaquatic animals may be influenced by dispersal across both rivers and land. The relative importance of these two modes of dispersal may vary across different species and with ecological conditions and evolutionary periods. The Pyrenean desman ( Galemys pyrenaicus ) is an endemic mammal of the Iberian Peninsula with a strong phylogeographic structure and semiaquatic habits, thus making it an ideal model to study the effects of river and overland dispersal on its genetic structure. Thanks to different types of noninvasive samples, we obtained an extensive sampling of the Pyrenean desman from the northwestern region of the Iberian Peninsula and sequenced two mitochondrial DNA fragments. We then analyzed, using an isolation-by-distance approach, the correlation between phylogenetic distances and geographical distances measured along both river networks and land to infer the relative importance of river and overland dispersal. We found that the correlations in the whole area and in a large basin were consistent with an effect of overland dispersal, which may be due to the postglacial colonization of new territories using terrestrial corridors and, possibly, a more extensive fluvial network that may have been present during the Holocene. However, in a small basin, likely to be less influenced by the impact of ancient postglacial dispersal, the correlations suggested significant overall effects of both overland and river dispersal, as expected for a semiaquatic mammal. Therefore, different scales and geographical regions reflect different aspects of the evolutionary history and ecology of this semiaquatic species using this isolation-by-distance method. The results we obtained may have crucial implications for the conservation of the Pyrenean desman because they reinforce the importance of interbasin dispersal for this species in the studied area and the need to protect the whole riverine ecosystem, including rivers, upland streams and terrestrial corridors between basins.

Depositional settings and evolution of a fjord system during the carboniferous glaciation in Northwest Argentina

NASA Astrophysics Data System (ADS)

Alonso-Muruaga, Pablo J.; Limarino, Carlos O.; Spalletti, Luis A.; Colombo Piñol, Ferrán

2018-07-01

Fjord systems, represented by glacial diamictites and postglacial transgressive shales, formed in the basins of western Argentina during the late Carboniferous Gondwana glaciation. Well exposed fjord deposits of the Guandacol Formation were studied in the Loma de Los Piojos region (Protoprecordillera), where they fill a 2.9 km wide paleovalley with steep side walls and a relatively flat floor. The valley cross-cuts Lower Devonian sandstones and Mississippian mudstones and sandstones, and provides evidence of glacial abrasion, including striated pavements and glacial microtopography (grooves, ridges, and striae). Based on the analysis of seven sedimentary logs, eight sedimentary facies in the valley fill were recognized: (A) Massive diamictites; (B) Laminated mudstones with dropstones; (C) Stratified diamictites; (D) Clast-supported conglomerates and sandstones; (E) Deformed diamictites, conglomerates and sandstones; (F) Folded diamictites; (G) Mudstones interbedded with sandstones, and (H) Stacked and amalgamated sandstones. These sedimentary facies are grouped into two principal facies assemblages that represent different stages of the paleovalley fill. Assemblage 1 is composed of diamictites (Facies A, C and F), laminated mudstones with dropstones (Facies B), and conglomerates (Facies D and E), which represent glacially influenced sedimentation in the paleovalley. Assemblage 2 represents the paleovalley fill when glacial influence ceased, and comprises laminated mudstones interbedded with sandstones (facies G) and stacked sandstone beds (facies H) that mostly record deltaic sedimentation. Stratigraphic relationships, plant fossils found in the paleovalley walls and palynological assemblages recovered in mudstones of facies D help to establish an early Pennsylvanian age for both the incision and the filling of the paleovalley. The studied paleovalley records an exceptional example of the western Gondwanan glacial to postglacial transition. Due to the continuous stratigraphic succession within the paleovalley as well as palynological, megafloristic and radiometric data, this example provides a complete framework of the late Carboniferous postglacial evolution in western Gondwana.

Fire-climate-human interactions during the postglacial period at Sunrise Ridge, Mount Rainier National Park, Washington (USA)

NASA Astrophysics Data System (ADS)

Walsh, Megan K.; Lukens, Michael L.; McCutcheon, Patrick T.; Burtchard, Greg C.

2017-12-01

With the creation of Mount Rainier National Park (MORA) in 1899 came the active management of the park's landscapes and a heavy emphasis on fire suppression. Today, managers at MORA seek to better manage current fire activity; however, this requires an improved understanding of past fire activity on the mountain. In this study high-resolution macroscopic charcoal analysis and pollen analysis of lake sediment records was used to reconstruct the postglacial fire and vegetation history for the Sunrise Ridge area of MORA. Fire activity was lowest during the Late Glacial when vegetation was sparse and climate was cool and dry. Fire activity increased during the early Holocene as the regional climate warmed and dried, and burnable biomass became more abundant. Fire activity continued to increase into the middle Holocene (until ca. 6600 cal yr BP) even as the regional climate became wetter and eventually cooler; the modern-day mesic forest and subalpine meadow landscapes of the park established at this time. Fire activity was generally highest and mean fire return intervals were lowest on Sunrise Ridge during the late Holocene, and are consistent with tree-ring based estimates of fire frequency. The similarity between the Sunrise Ridge and other paleofire records in the Pacific Northwest suggests that broad-scale climatic shifts, such as the retreat of the Cordilleran ice sheet and changes in annual insolation, as well as increased interannual climate variability (i.e., drought) particularly in the middle to late Holocene, were responsible for changes in fire activity during the postglacial period. However, abundant and increasing archaeological evidence from Sunrise Ridge during the middle to late Holocene suggests that humans may have also influenced the landscape at this time. It is likely that fires will continue to increase at MORA as drought becomes a more frequent occurrence in the Pacific Northwest.

Anatomy of the Kitimat fiord system, British Columbia

NASA Astrophysics Data System (ADS)

Shaw, John; Stacey, Cooper D.; Wu, Yongsheng; Lintern, D. Gwyn

2017-09-01

The geomorphic complexity of the Kitimat fiord system, on the active margin of British Columbia, Canada, is analysed from several perspectives. Sub-glacial landforms and sediments show that grounded ice exiting the fiord system at the last glacial maximum streamed down Moresby Trough towards the Queen Charlotte trough mouth fan. After brief halts on the inner shelf, grounded ice margins cleared the fiord threshold perhaps by c. 15.5 ka cal. yrs BP, and certainly before 13 ka cal. yrs BP. Just outside the fiords, meltwater plumes deposited stratified glaciomarine sediments interbedded with submarine slides. Inside the fiords, thick glaciomarine sediments were deposited, and large transverse moraines formed during temporary halts in retreat. Several glacial outburst floods eroded the Kitkiata moraine and deposited distinctive mud deposits. Postglacial sedimentation on fiord floors has been spatially variable: drifts of mud > 90 m-thick corresponding with areas of low current velocity alternate with areas of non-deposition and erosion corresponding with areas of high velocity. The fiord system hosts more than a hundred morphologically diverse fan deltas that can be classified in the Prior and Bornhold (1989, 1990) system. Submarine mass transport was most frequent immediately following ice retreat (15.5-11.5 ka cal. yrs BP). The largest event ( 1.2 km3) involved failure of glaciomarine sediment on a submarine moraine at Squally Channel, and consequent movement of material into the adjacent deep basin. This event occurred post-13 ka cal. yrs BP. In the postglacial phase, mass transport continued on a lesser scale up to the present day, most intensively in Kitimat Arm. From the perspective of glacial landforms, postglacial sedimentation and mass transport, this Pacific active margin fiord system has some parallels with fiord systems on Canada's east coast passive margin, and with Norwegian fiords, but the intensive development of Holocene fan deltas is strongly distinctive.

Bryophyte-cyanobacteria associations during primary succession in recently Deglaciated areas of Tierra del Fuego (Chile).

PubMed

Arróniz-Crespo, María; Pérez-Ortega, Sergio; De Los Ríos, Asunción; Green, T G Allan; Ochoa-Hueso, Raúl; Casermeiro, Miguel Ángel; de la Cruz, María Teresa; Pintado, Ana; Palacios, David; Rozzi, Ricardo; Tysklind, Niklas; Sancho, Leopoldo G

2014-01-01

Bryophyte establishment represents a positive feedback process that enhances soil development in newly exposed terrain. Further, biological nitrogen (N) fixation by cyanobacteria in association with mosses can be an important supply of N to terrestrial ecosystems, however the role of these associations during post-glacial primary succession is not yet fully understood. Here, we analyzed chronosequences in front of two receding glaciers with contrasting climatic conditions (wetter vs drier) at Cordillera Darwin (Tierra del Fuego) and found that most mosses had the capacity to support an epiphytic flora of cyanobacteria and exhibited high rates of N2 fixation. Pioneer moss-cyanobacteria associations showed the highest N2 fixation rates (4.60 and 4.96 µg N g-1 bryo. d-1) very early after glacier retreat (4 and 7 years) which may help accelerate soil development under wetter conditions. In drier climate, N2 fixation on bryophyte-cyanobacteria associations was also high (0.94 and 1.42 µg N g-1 bryo. d-1) but peaked at intermediate-aged sites (26 and 66 years). N2 fixation capacity on bryophytes was primarily driven by epiphytic cyanobacteria abundance rather than community composition. Most liverworts showed low colonization and N2 fixation rates, and mosses did not exhibit consistent differences across life forms and habitat (saxicolous vs terricolous). We also found a clear relationship between cyanobacteria genera and the stages of ecological succession, but no relationship was found with host species identity. Glacier forelands in Tierra del Fuego show fast rates of soil transformation which imply large quantities of N inputs. Our results highlight the potential contribution of bryophyte-cyanobacteria associations to N accumulation during post-glacial primary succession and further describe the factors that drive N2-fixation rates in post-glacial areas with very low N deposition.

Mathematical model of marine diesel engine simulator for a new methodology of self propulsion tests

NASA Astrophysics Data System (ADS)

Izzuddin, Nur; Sunarsih, Priyanto, Agoes

2015-05-01

As a vessel operates in the open seas, a marine diesel engine simulator whose engine rotation is controlled to transmit through propeller shaft is a new methodology for the self propulsion tests to track the fuel saving in a real time. Considering the circumstance, this paper presents the real time of marine diesel engine simulator system to track the real performance of a ship through a computer-simulated model. A mathematical model of marine diesel engine and the propeller are used in the simulation to estimate fuel rate, engine rotating speed, thrust and torque of the propeller thus achieve the target vessel's speed. The input and output are a real time control system of fuel saving rate and propeller rotating speed representing the marine diesel engine characteristics. The self-propulsion tests in calm waters were conducted using a vessel model to validate the marine diesel engine simulator. The simulator then was used to evaluate the fuel saving by employing a new mathematical model of turbochargers for the marine diesel engine simulator. The control system developed will be beneficial for users as to analyze different condition of vessel's speed to obtain better characteristics and hence optimize the fuel saving rate.

Horizontal gene transfer and mobile genetic elements in marine systems.

PubMed

Sobecky, Patricia A; Hazen, Tracy H

2009-01-01

The pool of mobile genetic elements (MGE) in microbial communities consists of viruses, plasmids, and associated elements (insertion sequences, transposons, and integrons) that are either self-transmissible or use mobile plasmids and viruses as vehicles for their dissemination. This mobilome facilitates the horizontal transfer of genes that promote the evolution and adaptation of microbial communities. Efforts to characterize MGEs from microbial populations resident in a variety of ecological habitats have revealed a surprisingly novel and seemingly untapped biodiversity. To better understand the impact of horizontal gene transfer (HGT), as well as the agents that promote HGT in marine ecosystems and to determine whether or not environmental parameters can effect the composition and structure of the mobilome in marine microbial communities, information on the distribution, diversity, and ecological traits of the marine mobilome is presented. In this chapter we discuss recent insights gained from different methodological approaches used to characterize the biodiversity and ecology of MGE in marine environments and their contributions to HGT. In addition, we present case studies that highlight specific HGT examples in coastal, open-ocean, and deep-sea marine ecosystems.

Contamination in marine turtle (Dermochelys coriaca) egg shells of Playon de Mexiquillo, Michoacan, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vazquez, G.F.; Reyes, M.C.; Fenandez, G.

Concern for the decreasing population sizes of marine turtles around the world is growing. Potential contamination within habitats of marine turtles, and human activities, such as poaching, modification of nesting sites, and capture of adult turtles, may be responsible for their decreasing populations. Little is known about the baseline levels and physiological effects of environmental contaminants on marine turtle populations. Responding to this concern, the Mexican government has designated areas along the Mexican coastline to preserve marine turtle nesting habitats. {open_quotes}Playon de Mexiquillo{close_quotes}, Michocan, Mexico is one of the coastal preservation areas located near the mouth of Rio la Manzanillamore » which flows between Sierra Madre del Sur and the Pacific Ocean. Samples of seawater, sand, and marine turtle egg (Dermochelys Coriaca) shells were collected monthly from October, 1992-March, 1993. Contaminants investigated were oil and grease, and metals (cadmium, copper, zinc, nickel, and lead). Seawater samples were collected where the turtles lay eggs in the preservation area and sand samples were taken from the area surrounding the eggs. 12 refs., 1 fig., 4 tabs.« less

Design and flight performance evaluation of the Mariners 6, 7, and 9 short-circuit current, open-circuit voltage transducers

NASA Technical Reports Server (NTRS)

Patterson, R. E.

1973-01-01

The purpose of the short-circuit voltage transducer is to provide engineering data to aid the evaluation of array performance during flight. The design, fabrication, calibration, and in-flight performance of the transducers onboard the Mariner 6, 7 and 9 spacecrafts are described. No significant differences were observed in the in-flight electrical performance of the three transducers. The transducers did experience significant losses due to coverslides or adhesive darkening, increased surface reflection, or spectral shifts within coverslide assembly. Mariner 6, 7 and 9 transducers showed non-cell current degradations of 3-1/2%, 3%, and 4%, respectively at Mars encounter and 6%, 3%, and 4-12%, respectively at end of mission. Mariner 9 solar Array Test 2 showed 3-12% current degradation while the transducer showed 4-12% degradation.

Volume and surface area size distribution, water mass and model fitting of GCE/CASE/WATOX marine aerosols

NASA Astrophysics Data System (ADS)

Kim, Y.; Sievering, H.; Boatman, J.

1990-06-01

As a part of the Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX), size distributions of marine aerosols were measured at two altitudes of about 2750 and 150 m above sea level (asl) over the size range 0.1 ˜ 32 μm. Lognormal fitting was applied to the corrected aerosol size spectra to determine the volume and surface area size distributions of the CASE-WATOX marine aerosols. Each aerosol size distribution was fitted with three lognormal distributions representing fine-, large-, and giant-particle modes. Water volume fraction and dry particle size of each aerosol size distribution were also calculated using empirical formulas for particle size as a function of relative humidity and particle type. Because of the increased influence from anthropogenic sources in the continental United States, higher aerosol volume concentrations were observed in the fine-particle mode near-shore off the east coast; 2.11 and 3.63 μm3 cm-3 for free troposphere (FT) and marine boundary layer (MBL), compared with the open-sea Bermuda area values; 0.13 and 0.74 μm3 cm-3 for FT and MBL. The large-particle mode exhibits the least variations in volume distributions between the east coast and open-sea Bermuda area, having a volume geometric median diameter (VGMD) between 1.4 and 1.6 μm and a geometric standard deviation between 1.57 and 1.68. For the giant-particle mode, larger VGMD and volume concentrations were observed for marine aerosols nearshore off the east coast than in the open-sea Bermuda area because of higher relative humidity and higher surface wind speed conditions. Wet VGMD and aerosol water volume concentrations at 15 m asl ship level were determined by extrapolating from those obtained by analysis of the CASE-WATOX aircraft aerosol data. Abundance of aerosol water in the MBL serves as an important pathway for heterogeneous conversion of SO2 in sea salt aerosol particles.

Passive monitoring and localization of marine mammals in open ocean environments using widely spaced bottom mounted hydrophones

NASA Astrophysics Data System (ADS)

Jarvis, Susan; Moretti, David; Morrissey, Ronald; Dimarzio, Nancy

2003-10-01

The Marine Mammal Monitoring on Navy Ranges (M3R) project has developed a toolset for passive detection and localization of marine mammals using the existing infrastructure of Navy's undersea ranges. The Office of Naval Research funded the M3R project as part of the Navy's effort to determine the effects of acoustic and other emissions on marine mammals and threatened/endangered species. A necessary first step in this effort is the creation of a baseline of behavior, which requires long-term monitoring of marine mammals. Such monitoring, in turn, requires the ability to detect and localize the animals. This paper will present the passive acoustic monitoring and localization tools developed under M3R. It will also present results of the deployment of the M3R tools at the Atlantic Undersea Test and Evaluation Center (AUTEC), Andros Island, Bahamas from June through November 2003. Finally, it will discuss current work to improve automated species classification.

Eukaryotic Life Inhabits Rhodolith-forming Coralline Algae (Hapalidiales, Rhodophyta), Remarkable Marine Benthic Microhabitats

NASA Astrophysics Data System (ADS)

Krayesky-Self, Sherry; Schmidt, William E.; Phung, Delena; Henry, Caroline; Sauvage, Thomas; Camacho, Olga; Felgenhauer, Bruce E.; Fredericq, Suzanne

2017-04-01

Rhodoliths are benthic calcium carbonate nodules accreted by crustose coralline red algae which recently have been identified as useful indicators of biomineral changes resulting from global climate change and ocean acidification. This study highlights the discovery that the interior of rhodoliths are marine biodiversity hotspots that function as seedbanks and temporary reservoirs of previously unknown stages in the life history of ecologically important dinoflagellate and haptophyte microalgae. Whereas the studied rhodoliths originated from offshore deep bank pinnacles in the northwestern Gulf of Mexico, the present study opens the door to assess the universality of endolithic stages among bloom-forming microalgae spanning different phyla, some of public health concerns (Prorocentrum) in marine ecosystems worldwide.

Desert Tortoise Head-start Program at Twentynine Palms Marine Base

DTIC Science & Technology

2013-04-02

Hillard. Shell hardness measurement in juvenile desert tortoises, Gopherus agassizii, Herpetological Review, (09 2011): 0. doi: 07/23/2012 2.00...yearlings released to the open desert. Herpetological Conservation and Biology.

Stalagmite carbon isotopes and dead carbon proportion (DCP) in a near-closed-system situation: An interplay between sulphuric and carbonic acid dissolution

NASA Astrophysics Data System (ADS)

Bajo, Petra; Borsato, Andrea; Drysdale, Russell; Hua, Quan; Frisia, Silvia; Zanchetta, Giovanni; Hellstrom, John; Woodhead, Jon

2017-08-01

In this study, the 'dead carbon proportion' (DCP) calculated from combined U-Th and radiocarbon analyses was used to explore the carbon isotope systematics in Corchia Cave (Italy) speleothems, using the example of stalagmite CC26 which grew during the last ∼12 ka. The DCP values in CC26 are among the highest ever recorded in a stalagmite, spanning the range 44.8-68.8%. A combination of almost closed-system conditions and sulphuric acid dissolution (SAD) are proposed as major drivers in producing such a high DCP with minor contribution from old organic matter from the deep vadose zone. The long-term decrease in both DCP and δ13C most likely reflects post-glacial soil recovery above the cave, with a progressive increase of soil CO2 contribution to the total dissolved inorganic carbon (DIC). Pronounced millennial-scale shifts in DCP and relatively small coeval but antipathetic changes in δ13C are modulated by the effects of hydrological variability on open and closed-system dissolution, SAD and prior calcite precipitation. Hence, the DCP in Corchia Cave speleothems represents an additional proxy for rainfall amount.

Rare-earth elements in the Permian Phosphoria Formation: Paleo proxies of ocean geochemistry

USGS Publications Warehouse

Piper, D.Z.; Perkins, R.B.; Rowe, H.D.

2007-01-01

The geochemistry of deposition of the Meade Peak Member of the Phosphoria Formation (MPM) in southeast Idaho, USA, a world-class sedimentary phosphate deposit of Permian age that extends over 300,000 km2, is ascertained from its rare earth element (REE) composition. Ratios of REE:Al2O3 suggest two sources-seawater and terrigenous debris. The seawater-derived marine fraction identifies bottom water in the Phosphoria Sea as O2-depleted, denitrifying (suboxic) most of the time, and seldom sulfate-reducing (anoxic). This interpretation is supported by earlier research that showed progressively greater ratios in the marine sediment fraction of Cr:Ni>V:Ni???Mo:Ni, relative to their ratios in seawater; for which marine Cr, V, and Mo can have a dominantly O2-depleted bottom-water source and Ni a photic-zone, largely algal, source. The water chemistry was maintained by a balance between bacterial oxidation of organic matter settling through the water column, determined largely by primary productivity in the photic zone, and the flux of oxidants into the bottom water via advection of seawater from the open ocean. Samples strongly enriched in carbonate fluorapatite, the dominant REE host mineral, have variable Er/Sm, Tm/Sm, and Yb/Sm ratios. Their distribution may represent greater advection of seawater between the Phosphoria Sea and open ocean during deposition of two ore zones than a center waste and greater upwelling of nutrient-enriched water into the photic zone. However, the mean rate of deposition of marine Ni, a trace nutrient of algae, and PO43-, a limiting nutrient, indicate that primary productivity was probably high throughout the depositional history. An alternative interpretation of the variable enrichments of Er, Tm, and Yb, relative to Sm, is that they may reflect temporally variable carbonate alkalinity of open-ocean seawater in Permian time. A more strongly negative Ce anomaly for all phosphatic units than the Ce anomaly of modern pelletal phosphate is further indicative of an elevated O2 concentration in the Permo-Carboniferous open ocean, as proposed by others, in contrast to the depletion of O2 in the bottom water of the Phosphoria Sea itself. The oceanographic conditions under which the deposit accumulated were likely similar to conditions under which many sedimentary phosphate deposits have accumulated and to conditions under which many black shales that are commonly phosphate poor have accumulated. A shortcoming of several earlier studies of these deposits has resulted from a failure to examine the marine fraction of elements separate from the terrigenous fraction. ?? 2007 Elsevier Ltd. All rights reserved.

Rare-earth elements in the Permian Phosphoria Formation: Paleo proxies of ocean geochemistry

NASA Astrophysics Data System (ADS)

Piper, D. Z.; Perkins, R. B.; Rowe, H. D.

2007-06-01

The geochemistry of deposition of the Meade Peak Member of the Phosphoria Formation (MPM) in southeast Idaho, USA, a world-class sedimentary phosphate deposit of Permian age that extends over 300,000 km 2, is ascertained from its rare earth element (REE) composition. Ratios of REE:Al 2O 3 suggest two sources—seawater and terrigenous debris. The seawater-derived marine fraction identifies bottom water in the Phosphoria Sea as O 2-depleted, denitrifying (suboxic) most of the time, and seldom sulfate-reducing (anoxic). This interpretation is supported by earlier research that showed progressively greater ratios in the marine sediment fraction of Cr:Ni>V:Ni≫Mo:Ni, relative to their ratios in seawater; for which marine Cr, V, and Mo can have a dominantly O 2-depleted bottom-water source and Ni a photic-zone, largely algal, source. The water chemistry was maintained by a balance between bacterial oxidation of organic matter settling through the water column, determined largely by primary productivity in the photic zone, and the flux of oxidants into the bottom water via advection of seawater from the open ocean. Samples strongly enriched in carbonate fluorapatite, the dominant REE host mineral, have variable Er/Sm, Tm/Sm, and Yb/Sm ratios. Their distribution may represent greater advection of seawater between the Phosphoria Sea and open ocean during deposition of two ore zones than a center waste and greater upwelling of nutrient-enriched water into the photic zone. However, the mean rate of deposition of marine Ni, a trace nutrient of algae, and PO 43-, a limiting nutrient, indicate that primary productivity was probably high throughout the depositional history. An alternative interpretation of the variable enrichments of Er, Tm, and Yb, relative to Sm, is that they may reflect temporally variable carbonate alkalinity of open-ocean seawater in Permian time. A more strongly negative Ce anomaly for all phosphatic units than the Ce anomaly of modern pelletal phosphate is further indicative of an elevated O 2 concentration in the Permo-Carboniferous open ocean, as proposed by others, in contrast to the depletion of O 2 in the bottom water of the Phosphoria Sea itself. The oceanographic conditions under which the deposit accumulated were likely similar to conditions under which many sedimentary phosphate deposits have accumulated and to conditions under which many black shales that are commonly phosphate poor have accumulated. A shortcoming of several earlier studies of these deposits has resulted from a failure to examine the marine fraction of elements separate from the terrigenous fraction.

The U.S. Marine Corps Combined Action Program (CAP): A Proposed Alternative Strategy for the Vietnam War

DTIC Science & Technology

2002-05-01

Vietnamese men abstained from premarital sex, they openly practiced mutual masturbation . 62 In western culture, a man’s business was a man’s business, but... practice of integrating Marine with native forces marked the beginning of a nearly six year endeavor entitled the Combined Action Program or CAP. Embraced...chain of command. While the CAP platoons drew from infantry battalions primarily, their ties to them remained administrative and informal in practice

Post-glacial evolution of Panicum virgatum: centers of diversity and gene pools revealed by SSR markers and cpDNA sequences

USDA-ARS?s Scientific Manuscript database

Switchgrass (Panicum virgatum) is native to the tallgrass prairie and associated ecosystems of the central and eastern USA. It is highly valued as a component in tallgrass prairie and savanna restoration and conservation projects and a potential bioenergy feedstock. The purpose of this study was to ...

Geologic evolution of the lower Connecticut River valley: Influence of bedrock geology, glacial deposits, and sea level

USGS Publications Warehouse

Stone, Janet R.; Lewis, Ralph S.

2016-01-01

This fieldtrip illustrates the character of the lower Connecticut River bedrock valley, in particular its depth, and the lithology and structure of bedrock units it crosses. It examines the character and distribution of the glaciodeltaic terraces that partially fill the valley and discusses the depth of postglacial incision into them.

Postglacial recolonization shaped the genetic diversity of the winter moth (Operophtera brumata) in Europe

Treesearch

Jeremy C. Andersen; Nathan P. Havill; Adalgisa Caccone; Joseph S. Elkinton

2017-01-01

Changes in climate conditions, particularly during the Quaternary climatic oscillations, have long been recognized to be important for shaping patterns of species diversity. For species residing in the western Palearctic, two commonly observed genetic patterns resulting from these cycles are as follows: (1) that the numbers and distributions of genetic lineages...

The forests of Michigan-from ice to axe to growth

Treesearch

Larry A. Leefers

2010-01-01

Michigan’s forests have evolved considerably during the past 4500 years. Post-glacial expansion of forests provided extensive, versatile resources for indigenous peoples. Eventually, these resources were exploited by immigrants to Michigan from Europe and the eastern US. Today, the forests are recovering and growing via natural regeneration and tree plantings, with...

On the Interaction between Marine Boundary Layer Cellular Cloudiness and Surface Heat Fluxes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazil, J.; Feingold, G.; Wang, Hailong

2014-01-02

The interaction between marine boundary layer cellular cloudiness and surface uxes of sensible and latent heat is investigated. The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind speed. The Advanced Research WRF model is used to conduct cloud-system-resolving simulations with interactive surface fluxes of sensible heat, latent heat, and of sea salt aerosol, and with a detailed representation of the interaction between aerosol particles and clouds. The mechanisms responsible for the temporal evolution and spatial distribution of the surface heat fluxes in the closed- and open-cell state are investigated and explained. Itmore » is found that the horizontal spatial structure of the closed-cell state determines, by entrainment of dry free tropospheric air, the spatial distribution of surface air temperature and water vapor, and, to a lesser degree, of the surface sensible and latent heat flux. The synchronized dynamics of the the open-cell state drives oscillations in surface air temperature, water vapor, and in the surface fluxes of sensible and latent heat, and of sea salt aerosol. Open-cell cloud formation, cloud optical depth and liquid water path, and cloud and rain water path are identified as good predictors of the spatial distribution of surface air temperature and sensible heat flux, but not of surface water vapor and latent heat flux. It is shown that by enhancing the surface sensible heat flux, the open-cell state creates conditions by which it is maintained. While the open-cell state under consideration is not depleted in aerosol, and is insensitive to variations in sea-salt fluxes, it also enhances the sea-salt flux relative to the closed-cell state. In aerosol-depleted conditions, this enhancement may replenish the aerosol needed for cloud formation, and hence contribute to the perpetuation of the open-cell state as well. Spatial homogenization of the surface fluxes is found to have only a small effect on cloud properties in the investigated cases. This indicates that sub-grid scale spatial variability in the surface flux of sensible and latent heat and of sea salt aerosol may not be required in large scale and global models to describe marine boundary layer cellular cloudiness.« less

New paleoreconstruction of transgressive stages in the northern part of Lake Ladoga, NW Russia.

NASA Astrophysics Data System (ADS)

Terekhov, Anton; Sapelko, Tatyana

2016-04-01

Lake Ladoga is one of the largest lakes in the world and the largest in Europe. The watershed of lake Ladoga covers the North-Western part of European Russia and the Eastern Finland. Lake basin is on the border between the Baltic shield and the East European Platform. The most consistent paleoreconstructions of Lake Ladoga history are based on bottom sediments of smaller lakes, which used to be a part of Ladoga in the past. The stages of Ladoga evolution are directly connected with the history of the Baltic Ice Lake (BIL) and of the Ancylus Lake. Water level of these lakes was significant higher than nowadays level. Lake Ladoga in its present limits used to be an Eastern gulf of BIL and Ancylus Lake. The preceding paleoreconstructions of Ladoga water level oscillations were undertaken by G. de Geer, J. Ailio, E. Hyyppä, K. Markov, D. Kvasov, D. Malakhovskiy, M. Ekman, G. Lak, N. Davydova, M. Saarnisto, D. Subetto and others. The new data on multivariate analysis of bottom sediments of lakes which used to belong to Ladoga, collected in the last few years, allows to create several maps of Ladoga transgressive stages in Late Glacial period and post-glacial time. A series of maps showing the extent of Ladoga transgression was created based on lake sediments multivariate analysis and a GIS-modeling using the digital elevation data with an accuracy of several meters and an open-source software (QGIS and SAGA). Due to post-glacial rebound of the lake watershed territory, GIS-modeling should comprise the extent of the glacioisostatic uplift, so the chart of a present-day uplift velocity for Fennoscandia of Ekman and Mäkinen was used. The new digital elevation models were calculated for several moments in the past, corresponding to the most probable dates of smaller lakes isolation from Lake Ladoga. Then, the basin of Ladoga was "filled" with water into GIS program to the levels sufficient for the smaller lakes to join and to split-off. The modern coastlines of Ladoga and of the other water bodies on the discussed territory to compare with transgressive stages were obtained by calculating the Normalized Difference Water Index (NDWI) from Landsat-8 images (http://landsat.usgs.gov/).

Large-Scale Trade in Legally Protected Marine Mollusc Shells from Java and Bali, Indonesia.

PubMed

Nijman, Vincent; Spaan, Denise; Nekaris, K Anne-Isola

2015-01-01

Tropical marine molluscs are traded globally. Larger species with slow life histories are under threat from over-exploitation. We report on the trade in protected marine mollusc shells in and from Java and Bali, Indonesia. Since 1987 twelve species of marine molluscs are protected under Indonesian law to shield them from overexploitation. Despite this protection they are traded openly in large volumes. We collected data on species composition, origins, volumes and prices at two large open markets (2013), collected data from wholesale traders (2013), and compiled seizure data by the Indonesian authorities (2008-2013). All twelve protected species were observed in trade. Smaller species were traded for 32,000 shells valued at USD500,000), chambered nautilus (Nautilus pompilius) (>3,000 shells, USD60,000) and giant clams (Tridacna spp.) (>2,000 shells, USD45,000) were traded in largest volumes. Two-thirds of this trade was destined for international markets, including in the USA and Asia-Pacific region. We demonstrated that the trade in protected marine mollusc shells in Indonesia is not controlled nor monitored, that it involves large volumes, and that networks of shell collectors, traders, middlemen and exporters span the globe. This impedes protection of these species on the ground and calls into question the effectiveness of protected species management in Indonesia; solutions are unlikely to be found only in Indonesia and must involve the cooperation of importing countries.

Sources and fate of microplastics in marine and beach sediments of the Southern Baltic Sea-a preliminary study.

PubMed

Graca, Bożena; Szewc, Karolina; Zakrzewska, Danuta; Dołęga, Anna; Szczerbowska-Boruchowska, Magdalena

2017-03-01

Microplastics' (particles size ≤5 mm) sources and fate in marine bottom and beach sediments of the brackish are strongly polluted Baltic Sea have been investigated. Microplastics were extracted using sodium chloride (1.2 g cm -3 ). Their qualitative identification was conducted using micro-Fourier-transform infrared spectroscopy (μFT-IR). Concentration of microplastics varied from 25 particles kg -1 d.w. at the open sea beach to 53 particles kg -1  d.w. at beaches of strongly urbanized bay. In bottom sediments, microplastics concentration was visibly lower compared to beach sediments (0-27 particles kg -1  d.w.) and decreased from the shore to the open, deep-sea regions. The most frequent microplastics dimensions ranged from 0.1 to 2.0 mm, and transparent fibers were predominant. Polyester, which is a popular fabrics component, was the most common type of microplastic in both marine bottom (50%) and beach sediments (27%). Additionally, poly(vinyl acetate) used in shipbuilding as well as poly(ethylene-propylene) used for packaging were numerous in marine bottom (25% of all polymers) and beach sediments (18% of all polymers). Polymer density seems to be an important factor influencing microplastics circulation. Low density plastic debris probably recirculates between beach sediments and seawater in a greater extent than higher density debris. Therefore, their deposition is potentially limited and physical degradation is favored. Consequently, low density microplastics concentration may be underestimated using current methods due to too small size of the debris. This influences also the findings of qualitative research of microplastics which provide the basis for conclusions about the sources of microplastics in the marine environment.

Coral decline threatens fish biodiversity in marine reserves.

PubMed

Jones, Geoffrey P; McCormick, Mark I; Srinivasan, Maya; Eagle, Janelle V

2004-05-25

The worldwide decline in coral cover has serious implications for the health of coral reefs. But what is the future of reef fish assemblages? Marine reserves can protect fish from exploitation, but do they protect fish biodiversity in degrading environments? The answer appears to be no, as indicated by our 8-year study in Papua New Guinea. A devastating decline in coral cover caused a parallel decline in fish biodiversity, both in marine reserves and in areas open to fishing. Over 75% of reef fish species declined in abundance, and 50% declined to less than half of their original numbers. The greater the dependence species have on living coral as juvenile recruitment sites, the greater the observed decline in abundance. Several rare coral-specialists became locally extinct. We suggest that fish biodiversity is threatened wherever permanent reef degradation occurs and warn that marine reserves will not always be sufficient to ensure their survival.

Production Biology of Phytoplankton

DTIC Science & Technology

1999-09-30

the publishing house, Universities Press (India) in Hyderabad ( Deccan ). New title: Breeding, Growth Rates, and Production of Marine Copepods. The...into sediment traps at 3 km depth indicate an onset of high primary production very soon after the arrival of the SWM and suggest a long open-sea...into the traps is disconcerting. For future modeling of plankton production in the open Arabian Sea, the use of two size classes of phytoplankton is

Standing Out From the Crowd: New Fish Recruits Have Unique δ15N Signatures in a Heavily Polluted Intermittently Open Estuary.

NASA Astrophysics Data System (ADS)

Hadwen, W. L.; Arthington, A. H.

2005-05-01

Intermittently open estuaries (IOEs) are the dominant coastal ecosystems of the Australian coastline. Conditions in IOEs range from freshwater when closed, to marine when open to the ocean, during which time marine fish often migrate into these systems. Many IOEs are facing increasing pressure from coastal development and ongoing nutrient inputs from industrial and urban sources have been shown to increase the δ15N isotope signatures of biota in receiving waters. In this study, we examined the food web structure of Tallows Creek, a relatively small IOE in northern NSW, Australia, which receives ongoing sewage treatment plant inputs. We first sampled Tallows Creek when it was closed to the ocean and found that all components of the food web had enriched δ15N signatures relative to biota sampled from a relatively undisturbed neighbouring system. However, samples collected immediately following an entrance opening event revealed some individuals of highly mobile taxa with δ15N signatures more typical of unpolluted estuaries. We suggest that these isotopically light individuals were recent migrants into Tallows Creek and that δ15N signatures can act as a guide to the importance of heavily polluted systems as nursery grounds for mobile taxa, owing to the distinction between resident and migrant signatures.

Small-scale managed marine areas over time: Developments and challenges in a local Fijian reef fishery.

PubMed

Fache, Elodie; Breckwoldt, Annette

2018-05-21

This paper investigates the Locally Managed Marine Area (LMMA) approach through looking at developments and challenges of community-based marine resource management over time, with a particular focus on Fiji in the South Pacific region. A diachronic perspective, based on two multi-method empirical studies, is used to exemplify the social complexities of the implementation of this LMMA approach in a specific island setting. This perspective connects local stakeholders' establishment and management of a LMMA covering their entire customary fishing rights area (iqoliqoli) with the national context articulated around the Fiji Locally Managed Marine Area (FLMMA) network, as well as with regional networking and international conservation dynamics. It especially explores the impacts of a small-scale marine closure (so-called tabu area) on the harvesting patterns in a portion of this LMMA, related aspects of formal and informal enforcement, and villagers' views of the health of their reef fishery. This case study reveals a lack of consensus on the current management of this closure as a conditionally-opened no-take area, whose temporary openings (re)produce social tensions, as well as a lack of consensus on the effects of this closure on the reef fishery, which is subject to poaching. The paper highlights that the articulation between conservation and extraction of marine resources, as well as between short-term and longer-term objectives of the community-based marine resource management in place, is a complex sociopolitical process even at the most local level. The discussion also points out that local observations and interpretations of coastal resource dynamics, and of the interplay between fishery and community changes, might be instrumental in addressing the limits of the area-based system of management inherent in the LMMA approach. These insights into both the development process of the LMMA approach and the challenges of its local implementation and maintenance efforts can be useful to consider the adjustments necessary for Fiji's achievement of its national coastal fisheries management strategy and its international ocean governance commitments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bison phylogeography constrains dispersal and viability of the Ice Free Corridor in western Canada

PubMed Central

Froese, Duane; Ives, John W.; Zazula, Grant D.; Letts, Brandon; Andrews, Thomas D.; Driver, Jonathan C.; Hall, Elizabeth; Hare, P. Gregory; Jass, Christopher N.; MacKay, Glen; Southon, John R.; Stiller, Mathias; Woywitka, Robin; Suchard, Marc A.

2016-01-01

The Ice Free Corridor has been invoked as a route for Pleistocene human and animal dispersals between eastern Beringia and more southerly areas of North America. Despite the significance of the corridor, there are limited data for when and how this corridor was used. Hypothetical uses of the corridor include: the first expansion of humans from Beringia into the Americas, northward postglacial expansions of fluted point technologies into Beringia, and continued use of the corridor as a contact route between the north and south. Here, we use radiocarbon dates and ancient mitochondrial DNA from late Pleistocene bison fossils to determine the chronology for when the corridor was open and viable for biotic dispersals. The corridor was closed after ∼23,000 until 13,400 calendar years ago (cal y BP), after which we find the first evidence, to our knowledge, that bison used this route to disperse from the south, and by 13,000 y from the north. Our chronology supports a habitable and traversable corridor by at least 13,000 cal y BP, just before the first appearance of Clovis technology in interior North America, and indicates that the corridor would not have been available for significantly earlier southward human dispersal. Following the opening of the corridor, multiple dispersals of human groups between Beringia and interior North America may have continued throughout the latest Pleistocene and early Holocene. Our results highlight the utility of phylogeographic analyses to test hypotheses about paleoecological history and the viability of dispersal routes over time. PMID:27274051

Bison phylogeography constrains dispersal and viability of the Ice Free Corridor in western Canada.

PubMed

Heintzman, Peter D; Froese, Duane; Ives, John W; Soares, André E R; Zazula, Grant D; Letts, Brandon; Andrews, Thomas D; Driver, Jonathan C; Hall, Elizabeth; Hare, P Gregory; Jass, Christopher N; MacKay, Glen; Southon, John R; Stiller, Mathias; Woywitka, Robin; Suchard, Marc A; Shapiro, Beth

2016-07-19

The Ice Free Corridor has been invoked as a route for Pleistocene human and animal dispersals between eastern Beringia and more southerly areas of North America. Despite the significance of the corridor, there are limited data for when and how this corridor was used. Hypothetical uses of the corridor include: the first expansion of humans from Beringia into the Americas, northward postglacial expansions of fluted point technologies into Beringia, and continued use of the corridor as a contact route between the north and south. Here, we use radiocarbon dates and ancient mitochondrial DNA from late Pleistocene bison fossils to determine the chronology for when the corridor was open and viable for biotic dispersals. The corridor was closed after ∼23,000 until 13,400 calendar years ago (cal y BP), after which we find the first evidence, to our knowledge, that bison used this route to disperse from the south, and by 13,000 y from the north. Our chronology supports a habitable and traversable corridor by at least 13,000 cal y BP, just before the first appearance of Clovis technology in interior North America, and indicates that the corridor would not have been available for significantly earlier southward human dispersal. Following the opening of the corridor, multiple dispersals of human groups between Beringia and interior North America may have continued throughout the latest Pleistocene and early Holocene. Our results highlight the utility of phylogeographic analyses to test hypotheses about paleoecological history and the viability of dispersal routes over time.

Oceanids command and control (C2) data system - Marine autonomous systems data for vehicle piloting, scientific data users, operational data assimilation, and big data

NASA Astrophysics Data System (ADS)

Buck, J. J. H.; Phillips, A.; Lorenzo, A.; Kokkinaki, A.; Hearn, M.; Gardner, T.; Thorne, K.

2017-12-01

The National Oceanography Centre (NOC) operate a fleet of approximately 36 autonomous marine platforms including submarine gliders, autonomous underwater vehicles, and autonomous surface vehicles. Each platform effectivity has the capability to observe the ocean and collect data akin to a small research vessel. This is creating a growth in data volumes and complexity while the amount of resource available to manage data remains static. The OceanIds Command and Control (C2) project aims to solve these issues by fully automating the data archival, processing and dissemination. The data architecture being implemented jointly by NOC and the Scottish Association for Marine Science (SAMS) includes a single Application Programming Interface (API) gateway to handle authentication, forwarding and delivery of both metadata and data. Technicians and principle investigators will enter expedition data prior to deployment of vehicles enabling automated data processing when vehicles are deployed. The system will support automated metadata acquisition from platforms as this technology moves towards operational implementation. The metadata exposure to the web builds on a prototype developed by the European Commission supported SenseOCEAN project and is via open standards including World Wide Web Consortium (W3C) RDF/XML and the use of the Semantic Sensor Network ontology and Open Geospatial Consortium (OGC) SensorML standard. Data will be delivered in the marine domain Everyone's Glider Observatory (EGO) format and OGC Observations and Measurements. Additional formats will be served by implementation of endpoints such as the NOAA ERDDAP tool. This standardised data delivery via the API gateway enables timely near-real-time data to be served to Oceanids users, BODC users, operational users and big data systems. The use of open standards will also enable web interfaces to be rapidly built on the API gateway and delivery to European research infrastructures that include aligned reference models for data infrastructure.

A statistical analysis of North East Atlantic (submicron) aerosol size distributions

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Monahan, C.; Greaney, R.; Beddows, D. C. S.; Harrison, R. M.; Ceburnis, D.; O'Dowd, C. D.

2011-12-01

The Global Atmospheric Watch research station at Mace Head (Ireland) offers the possibility to sample some of the cleanest air masses being imported into Europe as well as some of the most polluted being exported out of Europe. We present a statistical cluster analysis of the physical characteristics of aerosol size distributions in air ranging from the cleanest to the most polluted for the year 2008. Data coverage achieved was 75% throughout the year. By applying the Hartigan-Wong k-Means method, 12 clusters were identified as systematically occurring. These 12 clusters could be further combined into 4 categories with similar characteristics, namely: coastal nucleation category (occurring 21.3 % of the time), open ocean nucleation category (occurring 32.6% of the time), background clean marine category (occurring 26.1% of the time) and anthropogenic category (occurring 20% of the time) aerosol size distributions. The coastal nucleation category is characterised by a clear and dominant nucleation mode at sizes less than 10 nm while the open ocean nucleation category is characterised by a dominant Aitken mode between 15 nm and 50 nm. The background clean marine aerosol exhibited a clear bimodality in the sub-micron size distribution, with although it should be noted that either the Aitken mode or the accumulation mode may dominate the number concentration. However, peculiar background clean marine size distributions with coarser accumulation modes are also observed during winter months. By contrast, the continentally-influenced size distributions are generally more monomodal (accumulation), albeit with traces of bimodality. The open ocean category occurs more often during May, June and July, corresponding with the North East (NE) Atlantic high biological period. Combined with the relatively high percentage frequency of occurrence (32.6%), this suggests that the marine biota is an important source of new nano aerosol particles in NE Atlantic Air.

Mathematical model of marine diesel engine simulator for a new methodology of self propulsion tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izzuddin, Nur; Sunarsih,; Priyanto, Agoes

As a vessel operates in the open seas, a marine diesel engine simulator whose engine rotation is controlled to transmit through propeller shaft is a new methodology for the self propulsion tests to track the fuel saving in a real time. Considering the circumstance, this paper presents the real time of marine diesel engine simulator system to track the real performance of a ship through a computer-simulated model. A mathematical model of marine diesel engine and the propeller are used in the simulation to estimate fuel rate, engine rotating speed, thrust and torque of the propeller thus achieve the targetmore » vessel’s speed. The input and output are a real time control system of fuel saving rate and propeller rotating speed representing the marine diesel engine characteristics. The self-propulsion tests in calm waters were conducted using a vessel model to validate the marine diesel engine simulator. The simulator then was used to evaluate the fuel saving by employing a new mathematical model of turbochargers for the marine diesel engine simulator. The control system developed will be beneficial for users as to analyze different condition of vessel’s speed to obtain better characteristics and hence optimize the fuel saving rate.« less

High Ethanol Fuel Endurance: A Study of the Effects of Running Gasoline with 15% Ethanol Concentration in Current Production Outboard Four-Stroke Engines and Conventional Two-Stroke Outboard Marine Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hilbert, D.

2011-10-01

Three Mercury Marine outboard marine engines were evaluated for durability using E15 fuel -- gasoline blended with 15% ethanol. Direct comparison was made to operation on E0 (ethanol-free gasoline) to determine the effects of increased ethanol on engine durability. Testing was conducted using a 300-hour wide-open throttle (WOT) test protocol, a typical durability cycle used by the outboard marine industry. Use of E15 resulted in reduced CO emissions, as expected for open-loop, non-feedback control engines. HC emissions effects were variable. Exhaust gas and engine operating temperatures increased as a consequence of leaner operation. Each E15 test engine exhibited some deteriorationmore » that may have been related to the test fuel. The 9.9 HP, four-stroke E15 engine exhibited variable hydrocarbon emissions at 300 hours -- an indication of lean misfire. The 300HP, four-stroke, supercharged Verado engine and the 200HP, two-stroke legacy engine tested with E15 fuel failed to complete the durability test. The Verado engine failed three exhaust valves at 285 endurance hours while the 200HP legacy engine failed a main crank bearing at 256 endurance hours. All E0-dedicated engines completed the durability cycle without incident. Additional testing is necessary to link the observed engine failures to ethanol in the test fuel.« less

A Triassic plesiosaurian skeleton and bone histology inform on evolution of a unique body plan

PubMed Central

Wintrich, Tanja; Hayashi, Shoji; Houssaye, Alexandra; Nakajima, Yasuhisa; Sander, P. Martin

2017-01-01

Secondary marine adaptation is a major pattern in amniote evolution, accompanied by specific bone histological adaptations. In the aftermath of the end-Permian extinction, diverse marine reptiles evolved early in the Triassic. Plesiosauria is the most diverse and one of the longest-lived clades of marine reptiles, but its bone histology is least known among the major marine amniote clades. Plesiosaurians had a unique and puzzling body plan, sporting four evenly shaped pointed flippers and (in most clades) a small head on a long, stiffened neck. The flippers were used as hydrofoils in underwater flight. A wide temporal, morphological, and morphometric gap separates plesiosaurians from their closest relatives (basal pistosaurs, Bobosaurus). For nearly two centuries, plesiosaurians were thought to appear suddenly in the earliest Jurassic after the end-Triassic extinctions. We describe the first Triassic plesiosaurian, from the Rhaetian of Germany, and compare its long bone histology to that of later plesiosaurians sampled for this study. The new taxon is recovered as a basal member of the Pliosauridae, revealing that diversification of plesiosaurians was a Triassic event and that several lineages must have crossed into the Jurassic. Plesiosaurian histology is strikingly uniform and different from stem sauropterygians. Histology suggests the concurrent evolution of fast growth and an elevated metabolic rate as an adaptation to cruising and efficient foraging in the open sea. The new specimen corroborates the hypothesis that open ocean life of plesiosaurians facilitated their survival of the end-Triassic extinctions. PMID:29242826

Response of the mesozooplankton community of the St Lucia estuary, South Africa, to a mouth-opening event during an extended drought

NASA Astrophysics Data System (ADS)

Jerling, Hendrik L.; Vivier, Leon; Cyrus, Digby P.

2010-03-01

Mesozooplankton samples were collected between March 2005 and November 2008 in St Lucia, the largest estuarine lake system in South Africa. St Lucia experienced an extended period of drought before and during the present study. This drought led to natural closing of the estuary mouth as a result of flood-tide marine sediment deposition in 2002. In March 2007 the mouth was washed open by exceptionally high tidal and wave conditions. This resulted in an influx of a large volume of seawater. The mouth closed again in August 2007. Before opening of the mouth salinities in the Estuary were below 10 and large parts of North Lake dried up while South Lake retained a relatively stable waterbody with salinities between 10 and 30. When the mouth opened seawater flooded the system and salinities changed to about 35. After the mouth had closed again in August 2007 salinities increased in the lakes and decreased in the Estuary. The mesozooplankton community was dominated by copepods during all sampling sessions, especially by the estuarine calanoids Pseudodiaptomus stuhlmanni and Acartia natalensis. Mean mesozooplankton densities were significantly higher in South Lake before the mouth opened in March 2007. While zooplankton density decreased when the mouth opened species richness increased with the influx of coastal marine species, especially in the Estuary. Overall zooplankton densities declined progressively as salinity increased to hypersaline levels after mouth closure. Multivariate analyses supported significant differences between the lakes and the Estuary in terms of mesozooplankton community composition. Taxa mostly responsible for the similarities within and dissimilarity between sections of the system were the copepods P. stuhlmanni and A. natalensis with the meroplankton, crab zoeae and mollusc larvae, also contributing significantly after the mouth-opening event.

Surficial geologic map of Berrien County, Michigan, and the adjacent offshore area of Lake Michigan

USGS Publications Warehouse

Stone, Byron D.; Kincare, Kevin A.; O'Leary, Dennis W.; Newell, Wayne L.; Taylor, Emily M.; Williams, Van S.; Lundstrom, Scott C.; Abraham, Jared E.; Powers, Michael H.

2017-12-13

The surficial geologic map of Berrien County, southwestern Michigan (sheet 1), shows the distribution of glacial and postglacial deposits at the land surface and in the adjacent offshore area of Lake Michigan. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics, stratigraphic relationships, and age. Drill-hole information correlated in cross sections provides details of typical stratigraphic sequences that compose one or more penetrated geologic map units. A new bedrock geologic map (on sheet 2) includes contours of the altitude of the eroded top of bedrock and shows the distribution of middle Paleozoic shale and carbonate units in the subcrop. A sediment thickness map (also on sheet 2) portrays the extent of as much as 150 meters of surficial materials that overlie the bedrock surface.The major physical features of the county are related principally to deposits of the last Laurentide ice sheet that advanced and then retreated back through the region from about 19,000 to 14,000 radiocarbon years before present. Glacial and postglacial deposits underlie the entire county; shale bedrock crops out only in the adjacent offshore area on the bottom of Lake Michigan. All glacial deposits and glacial meltwater deposits in Berrien County are related to the late Wisconsinan glacial advances of the Lake Michigan ice lobe and its three regional recessional moraines, which cross the county as three north-northeast-trending belts.From east to west (oldest to youngest), the three moraine belts are known as the Kalamazoo, Valparaiso, and Lake Border morainic systems. The till-ridge morainic systems (Lake Border and local Valparaiso morainic systems) consist of multiple, elongate moraine ridges separated by till plains and lake-bottom plains. Tills in ground and end moraines in Berrien County are distinguished as informal units, and are correlated with three proposed regional till units in southwestern Michigan, characterized as clayey till, loamy till, or sandy loamy till that are based in part on correlation of silty tills and clay mineralogy. The stratified morainic systems (local Valparaiso and Kalamazoo morainic systems) are composed of multiple ice-marginal glacial-lake deltas and glaciolacustrine fans that form a contiguous array of deposits, welded together at their onlapping contacts, further related by the accordant altitudes of their delta topset plains. Their bounding ice-contact slopes repeatedly are aligned parallel to the regional trend of the receding ice margin. Ice-marginal (ice-contact) deltas were deposited in glacial lakes that expanded northward as the ice sheet retreated. Glaciofluvial topset beds, which overlie deltaic foreset and bottomset facies, fine away from the ice margin. Stratified deposits associated with the Valparaiso moraine were deposited in glacial Lakes Madron and Dowagiac. Subsequent deposits of glacial Lake Baroda preceded basin-wide deposits associated with various levels of Lake Michigan.Sheet 2 includes a series of 10 map figures that show cut-away three-dimensional time slices of the stratigraphic succession, from basal tills on bedrock, to ice-marginal deltas in the three large proglacial lakes, to stacked till/lake-bottom deposits related to the Lake Border ice margin readvances, to young deposits of glacial Lake Chicago and younger phases of other glacial lakes and the Chippewa lake lowstand.The pamphlet contains a discussion of the stratigraphic framework, descriptions of each depositional unit, and graphic logs of U.S. Geological Survey stratigraphic drill holes. The pamphlet also relates the geologic history of Berrien County, beginning with bedrock Paleozoic marine deposits, continuing through erosional effects of multiple glaciations and the detailed steps of late Wisconsinan ice-margin recession as recorded in the moraines, and the rise and fall of postglacial lake levels in the Lake Michigan basin.

Meridional contrasts in productivity changes driven by the Cenozoic opening of Drake Passage

NASA Astrophysics Data System (ADS)

Donnadieu, Y.; Ladant, J. B.; Bopp, L.; Wilson, P. A.; Lear, C. H.

2017-12-01

The progressive opening of Drake Passage across the Eocene and the Oligocene occurs contemporaneously to the long-term global cooling of the late Eocene, which culminated with the Eocene-Oligocene glaciation of Antarctica. Atmospheric pCO2 decline during the late Eocene is thought to have played a major role in the climatic shifts of the Eocene-Oligocene boundary, yet reasons behind CO2 variations remain obscure. Changes in marine productivity affecting the biological oceanic carbon pump represent a possible cause. Here, we explore whether and how the opening of Drake Passage may have affected the marine biogeochemistry, and in particular paleoproductivity changes, with the use of a fully coupled atmosphere-ocean-biogeochemical model (IPSL-CM5A). We find that the simulated changes to Drake Passage opening exhibit a uniform decrease in the low latitudes while the high latitude response is more spatially heterogeneous. Mechanistically, the low latitude productivity decrease is a consequence of the dramatic reorganization of the ocean circulation when Drake Passage opens, as the shift from a well ventilated to a swampier ocean drives nutrient depletion in the low latitudes. In the high latitudes, the onset of the Antarctic Circumpolar Current in the model exerts a strong control both on nutrient availability but also on regions of deep water formation, which results in non-uniform patterns of productivity change in the Southern Ocean. The qualitative agreement between geographically diverse long-term paleoproductivity records and the simulated variations suggests that the opening of Drake Passage may contribute to part of the long-term paleoproductivity signal recorded in the data.

Meeting Report: Methylmercury in Marine Ecosystems—From Sources to Seafood Consumers

PubMed Central

Chen, Celia Y.; Serrell, Nancy; Evers, David C.; Fleishman, Bethany J.; Lambert, Kathleen F.; Weiss, Jeri; Mason, Robert P.; Bank, Michael S.

2008-01-01

Mercury and other contaminants in coastal and open-ocean ecosystems are an issue of great concern globally and in the United States, where consumption of marine fish and shellfish is a major route of human exposure to methylmercury (MeHg). A recent National Institute of Environmental Health Sciences–Superfund Basic Research Program workshop titled “Fate and Bioavailability of Mercury in Aquatic Ecosystems and Effects on Human Exposure,” convened by the Dartmouth Toxic Metals Research Program on 15–16 November 2006 in Durham, New Hampshire, brought together human health experts, marine scientists, and ecotoxicologists to encourage cross-disciplinary discussion between ecosystem and human health scientists and to articulate research and monitoring priorities to better understand how marine food webs have become contaminated with MeHg. Although human health effects of Hg contamination were a major theme, the workshop also explored effects on marine biota. The workgroup focused on three major topics: a) the biogeochemical cycling of Hg in marine ecosystems, b) the trophic transfer and bioaccumulation of MeHg in marine food webs, and c) human exposure to Hg from marine fish and shellfish consumption. The group concluded that current understanding of Hg in marine ecosystems across a range of habitats, chemical conditions, and ocean basins is severely data limited. An integrated research and monitoring program is needed to link the processes and mechanisms of MeHg production, bioaccumulation, and transfer with MeHg exposure in humans. PMID:19079724

Electrical Components for Marine Renewable Energy Arrays: A Techno-Economic Review

DOE PAGES

Collin, Adam J.; Nambiar, Anup J.; Bould, David; ...

2017-11-27

This paper presents a review of the main electrical components that are expected to be present in marine renewable energy arrays. The review is put in context by appraising the current needs of the industry and identifying the key components required in both device and array-scale developments. For each component, electrical, mechanical and cost considerations are discussed; with quantitative data collected during the review made freely available for use by the community via an open access online repository. Here, this data collection updates previous research and addresses gaps specific to emerging offshore technologies, such as marine and floating wind, andmore » provides a comprehensive resource for the techno-economic assessment of offshore energy arrays.« less

Electrical Components for Marine Renewable Energy Arrays: A Techno-Economic Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collin, Adam J.; Nambiar, Anup J.; Bould, David

This paper presents a review of the main electrical components that are expected to be present in marine renewable energy arrays. The review is put in context by appraising the current needs of the industry and identifying the key components required in both device and array-scale developments. For each component, electrical, mechanical and cost considerations are discussed; with quantitative data collected during the review made freely available for use by the community via an open access online repository. Here, this data collection updates previous research and addresses gaps specific to emerging offshore technologies, such as marine and floating wind, andmore » provides a comprehensive resource for the techno-economic assessment of offshore energy arrays.« less

Eukaryotic Life Inhabits Rhodolith-forming Coralline Algae (Hapalidiales, Rhodophyta), Remarkable Marine Benthic Microhabitats

PubMed Central

Krayesky-Self, Sherry; Schmidt, William E.; Phung, Delena; Henry, Caroline; Sauvage, Thomas; Camacho, Olga; Felgenhauer, Bruce E.; Fredericq, Suzanne

2017-01-01

Rhodoliths are benthic calcium carbonate nodules accreted by crustose coralline red algae which recently have been identified as useful indicators of biomineral changes resulting from global climate change and ocean acidification. This study highlights the discovery that the interior of rhodoliths are marine biodiversity hotspots that function as seedbanks and temporary reservoirs of previously unknown stages in the life history of ecologically important dinoflagellate and haptophyte microalgae. Whereas the studied rhodoliths originated from offshore deep bank pinnacles in the northwestern Gulf of Mexico, the present study opens the door to assess the universality of endolithic stages among bloom-forming microalgae spanning different phyla, some of public health concerns (Prorocentrum) in marine ecosystems worldwide. PMID:28368049

Halogenated compounds from marine algae.

PubMed

Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

2010-08-09

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds.

Halogenated Compounds from Marine Algae

PubMed Central

Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

2010-01-01

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

Differentiating littering, urban runoff and marine transport as sources of marine debris in coastal and estuarine environments

PubMed Central

Willis, Kathryn; Denise Hardesty, Britta; Kriwoken, Lorne; Wilcox, Chris

2017-01-01

Marine debris is a burgeoning global issue with economic, ecological and aesthetic impacts. While there are many studies now addressing this topic, the influence of urbanisation factors such as local population density, stormwater drains and roads on the distribution of coastal litter remains poorly understood. To address this knowledge gap, we carried out standardized surveys at 224 transect surveys at 67 sites in two estuaries and along the open coast in Tasmania, Australia. We explored the relative support for three hypotheses regarding the sources of the debris; direct deposition by beachgoers, transport from surrounding areas via storm water drains and coastal runoff, and onshore transport from the marine system. We found strong support for all three mechanisms, however, onshore transport from the marine reservoir was the most important mechanism. Overall, the three models together explained 45.8 percent of the variation in our observations. Our results also suggest that most debris released into the marine environment is deposited locally, which may be the answer to where all the missing plastic is in the ocean. Furthermore, local interventions are likely to be most effective in reducing land-based inputs into the ocean. PMID:28281667

Monte Carlo simulation of a NaI(Tl) detector for in situ radioactivity measurements in the marine environment.

PubMed

Zhang, Yingying; Li, Changkai; Liu, Dongyan; Zhang, Ying; Liu, Yan

2015-04-01

To develop in situ NaI(Tl) detector for radioactivity measurement in the marine environment, the Monte Carlo N-Particle (MCNP) Transport Code was utilized to simulate the measurement of NaI(Tl) detector immersed in seawater, taking into account the material and geometry of the detector, and the interactions between the photons with the atoms of the seawater and the detector. The simulation results of the marine detection efficiency and distance were deduced and analyzed. In order to test their reliability, the field measurement was made at open sea and the experimental value of the marine detection efficiency was deduced and seems to be in good agreement with the simulated one. The minimum detectable activity for (137)Cs in the seawater of NaI(Tl) detector developed was determined mathematically at last. The simulation method and results in the paper can be used for the better design and quantitative calculation of in situ NaI(Tl) detector for radioactivity measurement in the marine environment, and also for some applications such as the installation on the marine monitoring platform and the quantitative analysis of radionuclides. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differentiating littering, urban runoff and marine transport as sources of marine debris in coastal and estuarine environments

NASA Astrophysics Data System (ADS)

Willis, Kathryn; Denise Hardesty, Britta; Kriwoken, Lorne; Wilcox, Chris

2017-03-01

Marine debris is a burgeoning global issue with economic, ecological and aesthetic impacts. While there are many studies now addressing this topic, the influence of urbanisation factors such as local population density, stormwater drains and roads on the distribution of coastal litter remains poorly understood. To address this knowledge gap, we carried out standardized surveys at 224 transect surveys at 67 sites in two estuaries and along the open coast in Tasmania, Australia. We explored the relative support for three hypotheses regarding the sources of the debris; direct deposition by beachgoers, transport from surrounding areas via storm water drains and coastal runoff, and onshore transport from the marine system. We found strong support for all three mechanisms, however, onshore transport from the marine reservoir was the most important mechanism. Overall, the three models together explained 45.8 percent of the variation in our observations. Our results also suggest that most debris released into the marine environment is deposited locally, which may be the answer to where all the missing plastic is in the ocean. Furthermore, local interventions are likely to be most effective in reducing land-based inputs into the ocean.

Evidence of the Zanclean megaflood in the eastern Mediterranean Basin.

PubMed

Micallef, Aaron; Camerlenghi, Angelo; Garcia-Castellanos, Daniel; Cunarro Otero, Daniel; Gutscher, Marc-André; Barreca, Giovanni; Spatola, Daniele; Facchin, Lorenzo; Geletti, Riccardo; Krastel, Sebastian; Gross, Felix; Urlaub, Morelia

2018-01-18

The Messinian salinity crisis (MSC) - the most abrupt, global-scale environmental change since the end of the Cretaceous - is widely associated with partial desiccation of the Mediterranean Sea. A major open question is the way normal marine conditions were abruptly restored at the end of the MSC. Here we use geological and geophysical data to identify an extensive, buried and chaotic sedimentary body deposited in the western Ionian Basin after the massive Messinian salts and before the Plio-Quaternary open-marine sedimentary sequence. We show that this body is consistent with the passage of a megaflood from the western to the eastern Mediterranean Sea via a south-eastern Sicilian gateway. Our findings provide evidence for a large amplitude drawdown in the Ionian Basin during the MSC, support the scenario of a Mediterranean-wide catastrophic flood at the end of the MSC, and suggest that the identified sedimentary body is the largest known megaflood deposit on Earth.

Summary and synthesis: past and future changes in the Alaskan Boreal Forest.

Treesearch

F. Stuart Chapin; David McGuire; Roger W. Ruess; Marilyn W. Walker; Richard D. Boone; Mary E. Edwards; Bruce P. Finney; Larry D. Hinzman; Jeremy B. Jones; Glenn P. Juday; Eric S. Kasischke; Knut Kielland; Andrea H. Lloyd; Mark W. Oswood; Chien-Lu Ping; Eric Rexstad; Vladimir E. Romanovsky; Joshua P. Schimel; Elena B. Sparrow; Bjartmar Sveinbjörnsson; David W. Valentine; Keith Van Cleve; David L. Verbyla; Leslie A. Viereck; Richard A. Werner; Tricia L. Wurtz; John Yarie

2006-01-01

Historically the boreal forest has experienced major changes, and it remains a highly dynamic biome today. During cold phases of Quaternary climate cycles, forests were virtually absent from Alaska, and since the postglacial re-establishment of forests ca 13,000 years ago, here have been periods of both relative stability and rapid change (Chapter 5). Today, the...

Molecular identification of Armillaria gallica from the Niobrara Valley Preserve in Nebraska

Treesearch

Mee-Sook Kim; Ned B. Klopfenstein

2011-01-01

Armillaria isolates were collected from a unique forest ecosystem in the Niobrara Valley Preserve in Nebraska, USA, which comprises a glacial and early postglacial refugium in the central plains of North America. The isolates were collected from diverse forest trees representing a unique mixture of forest types. Combined methods of rDNA sequencing and flow cytometric...

DNA from bird-dispersed seed and wind-disseminated pollen provides insights into postglacial colonization and population genetic structure of whitebark pine (Pinus albicaulis)

Treesearch

Bryce A. Richardson; Steven J. Runsfeld; Ned B. Klopfenstein

2002-01-01

Uniparentally inherited mitochondrial (mt)DNA and chloroplast (cp)DNA microsatellites (cpSSRs) were used to examine population genetic structure and biogeographic patterns of bird-dispersed seed and wind-disseminated pollen of whitebark pine (Pinus albicaulis Engelm.). Sampling was conducted from 41 populations throughout the range of the species....

Measurement and Interpretation of Crustal Deformation Rates Associated with Postglacial Rebound

NASA Technical Reports Server (NTRS)

Davis, James L.

1998-01-01

This project involves obtaining GPS measurements in Scandinavia, and using the measurements to estimate the viscosity profile of the Earth's mantle and to correct tide-gauge measurements for the rebound effect. Many aspects of this project have been reported in the literature (see Section III). In Section II, we report on the primary geodetic results from this project.

Sterols of a contemporary lacustrine sediment. [in English postglacial lake

NASA Technical Reports Server (NTRS)

Gaskell, S. J.; Eglinton, G.

1976-01-01

Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

Two disjunct Pleistocene populations and anisotropic postglacial expansion shaped the current genetic structure of the relict plant Amborella trichopoda

PubMed Central

Tournebize, Rémi; Manel, Stéphanie; Vigouroux, Yves; Munoz, François; de Kochko, Alexandre

2017-01-01

Past climate fluctuations shaped the population dynamics of organisms in space and time, and have impacted their present intra-specific genetic structure. Demo-genetic modelling allows inferring the way past demographic and migration dynamics have determined this structure. Amborella trichopoda is an emblematic relict plant endemic to New Caledonia, widely distributed in the understory of non-ultramafic rainforests. We assessed the influence of the last glacial climates on the demographic history and the paleo-distribution of 12 Amborella populations covering the whole current distribution. We performed coalescent genetic modelling of these dynamics, based on both whole-genome resequencing and microsatellite genotyping data. We found that the two main genetic groups of Amborella were shaped by the divergence of two ancestral populations during the last glacial maximum. From 12,800 years BP, the South ancestral population has expanded 6.3-fold while the size of the North population has remained stable. Recent asymmetric gene flow between the groups further contributed to the phylogeographical pattern. Spatially explicit coalescent modelling allowed us to estimate the location of ancestral populations with good accuracy (< 22 km) and provided indications regarding the mid-elevation pathways that facilitated post-glacial expansion. PMID:28820899

Post-Glacial and Paleo-Environmental History of the West Coast of Vancouver Island

NASA Astrophysics Data System (ADS)

Dallimore, A.; Enkin, R. J.

2005-12-01

Annually laminated sediments in anoxic fjords are potentially ideal paleoclimate recorders, particularly once proxy measurements for atmospheric, oceanographic and sedimentological conditions have been calibrated. On the west coast of Canada, these sediments also record the changing environment as glaciers retreated from this area about 12 ka y BP. In Effingham Inlet, a 40 m core taken from the French ship the Marion Dufresne as part of the international IMAGES/PAGES program, gives evidence of an isolation basin at maximum glacial isostatic rebound and lowest paleo-sea level followed by eustatic sea level rise about 10 ka y BP. The Late Pleistocene record also marks dramatic changes in glacial sedimentary source and transport. Excellent chronological control is provided by complementary yet independent dating methods including radiocarbon dates on both plants and shells, identification of the Mazama Ash, varve counting and paleomagnetic, paleosecular variation correlations in the lower, pro-glacial section of the core which does not contain organic material. Paleoenvironmental evidence from this core provides information on immediate post-glacial conditions along the coast and rapid climatic changes throughout the Holocene, with implications for the possibility of early human migration routes and refugia.

The resilience of postglacial hunter-gatherers to abrupt climate change.

PubMed

Blockley, Simon; Candy, Ian; Matthews, Ian; Langdon, Pete; Langdon, Cath; Palmer, Adrian; Lincoln, Paul; Abrook, Ashley; Taylor, Barry; Conneller, Chantal; Bayliss, Alex; MacLeod, Alison; Deeprose, Laura; Darvill, Chris; Kearney, Rebecca; Beavan, Nancy; Staff, Richard; Bamforth, Michael; Taylor, Maisie; Milner, Nicky

2018-05-01

Understanding the resilience of early societies to climate change is an essential part of exploring the environmental sensitivity of human populations. There is significant interest in the role of abrupt climate events as a driver of early Holocene human activity, but there are very few well-dated records directly compared with local climate archives. Here, we present evidence from the internationally important Mesolithic site of Star Carr showing occupation during the early Holocene, which is directly compared with a high-resolution palaeoclimate record from neighbouring lake beds. We show that-once established-there was intensive human activity at the site for several hundred years when the community was subject to multiple, severe, abrupt climate events that impacted air temperatures, the landscape and the ecosystem of the region. However, these results show that occupation and activity at the site persisted regardless of the environmental stresses experienced by this society. The Star Carr population displayed a high level of resilience to climate change, suggesting that postglacial populations were not necessarily held hostage to the flickering switch of climate change. Instead, we show that local, intrinsic changes in the wetland environment were more significant in determining human activity than the large-scale abrupt early Holocene climate events.

Modern coral reefs of western Atlantic: new geological perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacIntyre, I.G.

1988-11-01

Contrary to popular belief of the late 1960s, western Atlantic Holocene reefs have a long history and are not feeble novice nearshore veneers that barely survived postglacial temperatures. Rather, the growth of these reefs kept pace with the rising seas of the Holocene transgression and their development was, for the most part, controlled by offshore wave-energy conditions and the relationship between changing sea levels and local shelf topography. Thus, the outer shelves of the eastern Caribbean in areas of high energy have relict reefs consisting predominantly of Acropora palmata, a robust shallow-water coral. The flooding of adjacent shelves during themore » postglacial transgression introduced stress conditions that terminated the growth of these reefs. When, about 7000 yr ago, shelf-water conditions improved, scattered deeper water coral communities reestablished themselves on these stranded shelf-edge reefs, and fringing and bank-barrier reefs began to flourish in shallow coastal areas. At the same time, the fragile and rapidly growing Acropora cervicornis and other corals flourished at greater depths on the more protected shelves of the western Caribbean and the Gulf of Mexico. As a result, late Holocene buildups more than 30 m thick developed in those areas. 7 figures.« less

Response of faults to climate-driven changes in ice and water volumes on Earth's surface.

PubMed

Hampel, Andrea; Hetzel, Ralf; Maniatis, Georgios

2010-05-28

Numerical models including one or more faults in a rheologically stratified lithosphere show that climate-induced variations in ice and water volumes on Earth's surface considerably affect the slip evolution of both thrust and normal faults. In general, the slip rate and hence the seismicity of a fault decreases during loading and increases during unloading. Here, we present several case studies to show that a postglacial slip rate increase occurred on faults worldwide in regions where ice caps and lakes decayed at the end of the last glaciation. Of note is that the postglacial amplification of seismicity was not restricted to the areas beneath the large Laurentide and Fennoscandian ice sheets but also occurred in regions affected by smaller ice caps or lakes, e.g. the Basin-and-Range Province. Our results do not only have important consequences for the interpretation of palaeoseismological records from faults in these regions but also for the evaluation of the future seismicity in regions currently affected by deglaciation like Greenland and Antarctica: shrinkage of the modern ice sheets owing to global warming may ultimately lead to an increase in earthquake frequency in these regions.

Viscoelastic responses of a hard transition zone - Effects on postglacial uplifts and rotational signatures

NASA Technical Reports Server (NTRS)

Spada, Giorgio; Sabadini, Roberto; Yuen, David A.

1991-01-01

A five-layer viscoelastic spherical model is used to calculate the transient displacements of postglacial rebound, the induced polar motions, and the temporal variations of the geopotential up to degree 8 of the zonal coefficients. Two models - one with two viscoelastic layers separated at 670 km, and the other with three layers in which a hard garnet layer lies between the upper and lower mantle - are compared. Forward modeling shows that it may be possible to discern the presence of a hard garnet layer with a viscosity of at least ten times greater than the upper mantle, on the basis of uplift data near the center of the former Laurentide ice-sheet and from polar wander and j2 data. Temporal variations of higher gravity harmonics, such as j6 and j8, can potentially place even tighter constraints on the rheological properties of the hard transition zone. A lower mantle viscosity between 2 and 4 x 10 to the 22nd Pa is generally preferred in models with a garnet layer which may be as large as 50 times more viscous than the upper mantle.

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

PubMed Central

Nielsen, Karina J.

2003-01-01

Human activities are significantly altering nutrient regimes and the abundance of consumers in coastal ecosystems. A field experiment in an open-coast, upwelling ecosystem showed that small increases in nutrients increased the biomass and evenness of tide pool macrophytes where consumer abundance and nutrient loading rates were low. Consumers, when abundant, had negative effects on the diversity and biomass of macrophytes. Nutrient loading increases and consumers are less abundant and efficient as wave exposure increases along open coastlines. Experimentally reversing the natural state of nutrient supply and consumer pressure at a wave-protected site to match wave-exposed sites caused the structure of the macrophyte assemblage to converge on that found naturally in wave-exposed pools. The increases in evenness and abundance were driven by increases in structurally complex functional groups. In contrast, increased nutrient loading in semienclosed marine or estuarine ecosystems is typically associated with declines in macrophyte diversity because of increases in structurally simple and opportunistic functional groups. If nutrient concentration of upwelled waters changes with climatic warming or increasing frequency of El Niños, as predicted by some climate models, these results suggest that macrophyte abundance and evenness along wave-swept open-coasts will also change. Macrophytes represent a significant fraction of continental shelf production and provide important habitat for many marine species. The combined effects of shifting nutrient regimes and overexploitation of consumers may have unexpected consequences for the structure and functioning of open-coast communities. PMID:12796509

Nutrient loading and consumers: agents of change in open-coast macrophyte assemblages.

PubMed

Nielsen, Karina J

2003-06-24

Human activities are significantly altering nutrient regimes and the abundance of consumers in coastal ecosystems. A field experiment in an open-coast, upwelling ecosystem showed that small increases in nutrients increased the biomass and evenness of tide pool macrophytes where consumer abundance and nutrient loading rates were low. Consumers, when abundant, had negative effects on the diversity and biomass of macrophytes. Nutrient loading increases and consumers are less abundant and efficient as wave exposure increases along open coastlines. Experimentally reversing the natural state of nutrient supply and consumer pressure at a wave-protected site to match wave-exposed sites caused the structure of the macrophyte assemblage to converge on that found naturally in wave-exposed pools. The increases in evenness and abundance were driven by increases in structurally complex functional groups. In contrast, increased nutrient loading in semienclosed marine or estuarine ecosystems is typically associated with declines in macrophyte diversity because of increases in structurally simple and opportunistic functional groups. If nutrient concentration of upwelled waters changes with climatic warming or increasing frequency of El Niños, as predicted by some climate models, these results suggest that macrophyte abundance and evenness along wave-swept open-coasts will also change. Macrophytes represent a significant fraction of continental shelf production and provide important habitat for many marine species. The combined effects of shifting nutrient regimes and overexploitation of consumers may have unexpected consequences for the structure and functioning of open-coast communities.

Glacier Change and Biologic Succession: a new Alaska Summer Research Academy (ASRA) Science Camp Module for Grades 8-12 in Glacier Bay National Park, Alaska

NASA Astrophysics Data System (ADS)

Connor, C. L.; Drake, J.; Good, C.; Fatland, R.; Hakala, M.; Woodford, R.; Donohoe, R.; Brenner, R.; Moriarty, T.

2008-12-01

During the summer of 2008, university faculty and instructors from southeast Alaska joined the University Alaska Fairbanks(UAF)Alaska Summer Research Academy(ASRA)to initiate a 12-day module on glacier change and biologic succession in Glacier Bay National Park. Nine students from Alaska, Colorado, Massachusetts, and Texas, made field observations and collected data while learning about tidewater glacier dynamics, plant succession, post-glacial uplift, and habitat use of terrestrial and marine vertebrates and invertebrates in this dynamic landscape that was covered by 6,000 km2 of ice just 250 years ago. ASRA students located their study sites using GPS and created maps in GIS and GOOGLE Earth. They deployed salinometers and temperature sensors to collect vertical profiles of seawater characteristics up-bay near active tidewater glacier termini and down-bay in completely deglaciated coves. ASRA student data was then compared with data collected during the same time period by Juneau undergraduates working on the SEAMONSTER project in Mendenhall Lake. ASRA students traversed actively forming, up-bay recessional moraines devoid of vegetation, and the fully reforested Little Ice Age terminal moraine near Park Headquarters in the lower bay region. Students surveyed marine organisms living between supratidal and subtidal zones near glaciers and far from glaciers, and compared up-bay and down-bay communities. Students made observations and logged sightings of bird populations and terrestrial mammals in a linear traverse from the bay's northwestern most fjord near Mt. Fairweather for 120 km to the bay's entrance, south of Park Headquarters at Bartlett Cove. One student constructed an ROV and was able to deploy a video camera and capture changing silt concentrations in the water column as well as marine life on the fjord bottom. Students also observed exhumed Neoglacial spruce forests and visited outcrops of Silurian reef faunas, now fossilized in Alexander terrane limestones in the lower bay. Park Service naturalists joined the expedition and provided important resource information to the students. ASRA students and faculty returned to the Fairbanks campus at the end of the second week where students presented their work to 114 of their peers, distributed across 15 different science modules. Camp faculty, dorm resident assistants, camp staff, an enthusiastic crowd of Fairbanks community members, and one Nobel Laureate in Chemistry rounded out the audience. This was the 8th summer of the UAF-ASRA Camp.

Fluvial landscapes evolution in the Gangkou River basin of southern Taiwan: Evidence from the sediment cores

NASA Astrophysics Data System (ADS)

Chen, Jia-Hong; Chyi, Shyh-Jeng; Yen, Jiun-Yee; Lin, Li-Hung; Yen, I.-Chin; Yu, Neng-Ti; Ho, Lih-Der; Jen, Chia-Hung

2017-04-01

The Gangkou River basin is the largest basin in the eastern Hengchun Peninsula of Taiwan. Its main river length is 31km and the basin area is 102sq. km. The width of the active channel is relatively narrow, but the valley from the middle to downstream is remarkably wide, indicating a feature of underfit stream. We drilled two sediment cores in the downstream area, including a 30m core (core-A) from a higher terrace, which is 14m above mean sea level, and a 20m core (core-B) from a lower terrace, which is 4m above mean sea level. Most of the sediments in the core-A are mud, which represents the flood plain facies, and 14C dates in the core-A range from 11ka to 7ka BP. Furthermore, the sediment layers reveal signals of marine events at the core depths of 5m to 11m by X-ray fluorescence. In the core-B, there is an erosional surface at the core depth of 5m. The age of the fluvial gravel layer above the erosional surface is about 0.4ka BP, and the mud layer top the surface is about 8.5ka BP. The preliminary results show that (1) as the tectonic uplift rate induced by the marine terraces around the basin is 1.0 to 2.5 mm/yr, and the accumulation rate of the mud layer in the basin is 6.7 to 8.7 mm/yr, the sediments infilling (more than 30-meters-thick) in the downstream area of the basin should be the results of the lower tectonic uplifting and the higher post-glacial sea level rise and; (2) the marine sediment layer with 14C dates of 7.5ka to 8.5ka BP is very likely the remain of the maximum flooding surface (MFS) in the early Holocene. These results indicate that the fluvial landscapes evolution of the basin was controlled by the sea-level; (3) the erosional surface in the core-B indicates the Gangkou River continuously erode the infilling sediments from 7ka to 0.4ka BP. Previous studies show that the sea-level around Taiwan gradually declined from its high stand since 6ka, we proposed that the continuous erosion was probably the results of tectonic uplifting and eustatic sea-level fall.

The Australian Integrated Marine Observing System

NASA Astrophysics Data System (ADS)

Proctor, R.; Meyers, G.; Roughan, M.; Operators, I.

2008-12-01

The Integrated Marine Observing System (IMOS) is a 92M project established with 50M from the National Collaborative Research Infrastructure Strategy (NCRIS) and co-investments from 10 operators including Universities and government agencies (see below). It is a nationally distributed set of equipment established and maintained at sea, oceanographic data and information services that collectively will contribute to meeting the needs of marine research in both open oceans and over the continental shelf around Australia. In particular, if sustained in the long term, it will permit identification and management of climate change in the marine environment, an area of research that is as yet almost a blank page, studies relevant to conservation of marine biodiversity and research on the role of the oceans in the climate system. While as an NCRIS project IMOS is intended to support research, the data streams are also useful for many societal, environmental and economic applications, such as management of offshore industries, safety at sea, management of marine ecosystems and fisheries and tourism. The infrastructure also contributes to Australia's commitments to international programs of ocean observing and international conventions, such as the 1982 Law of the Sea Convention that established the Australian Exclusive Economic Zone, the United Nations Framework Convention on Climate Change, the Global Ocean Observing System and the intergovernmental coordinating activity Global Earth Observation System of Systems. IMOS is made up of nine national facilities that collect data, using different components of infrastructure and instruments, and two facilities that manage and provide access to data and enhanced data products, one for in situ data and a second for remotely sensed satellite data. The observing facilities include three for the open (bluewater) ocean (Argo Australia, Enhanced Ships of Opportunity and Southern Ocean Time Series), three facilities for coastal currents and water properties (Moorings, Ocean Gliders and HF Radar) and three for coastal ecosystems (Acoustic Tagging and Tracking, Autonomous Underwater Vehicle and a biophysical sensor network on the Great Barrier Reef). The value from this infrastructure investment lies in the coordinated deployment of a wide range of equipment aimed at deriving critical data sets that serve multiple applications. Additional information on IMOS is available at the website (http://www.imos.org.au). The IMOS Operators are Australian Institute of Marine Science, James Cook University, Sydney Institute of Marine Science, Geoscience Australia, Bureau of Meteorology, South Australia Research and Development Institute, University of Western Australia, Curtin University of Technology, CSIRO Marine and Atmospheric Research, University of Tasmania.

Paleoenvironmental analysis and paleobiogeography of the Langhian-Serravallian succession in Wadi Trakee, westcentral Sinai (Egypt): An implication for Mediterranean and Paratethys faunal exchange

NASA Astrophysics Data System (ADS)

Ied, I. M.; Nagwa Ibrahim, A.; Abd-Elaziz, M. A.

2018-01-01

This paper aims to determine the probable paleoenvironments (ecozones) of Miocene sediments at Wadi Trakee, westcentral Sinai, Egypt. To achieve this work, both benthonic and planktonic foraminiferal assemblages were identified. Six paleoecologic zones (ecozones) are distinguished from Wadi Trakee Miocene succession in west-central Sinai; open marine environments were predominated during the deposition of these sediments; occasionally lagoonal. Great oscillation in sea level represented by lagoons and open marine conditions were prevailed in the earliest Langhian that came after the latest Burdigalian sea regression this was followed by great sea transgression phase and open marine environments during the latest Langhian. Serravallian Sea came after sea regression and a short hiatus preserved at the end of Langhian and ended by lagoons environments in the latest Serravallian. Seventy-one species of the identified benthic foraminifera indicate the Langhian, whereas forty-eight species recorded from the Serravallian. Due to the great similarity between the identified fauna with the previously recorded from the Paratethys countries, it can be suggested that high rate of faunal exchanges occurred and sea connections between the Mediterranean and Paratethys were occurred during these ages. Two unconformity surfaces are detected, the first lies within the Langhian while the second lies at the end of the Serravallian. Thirty-two planktonic foraminiferal species are also recorded from the Langhian - Serravallian succession that helped us to subdivide the studied succession into two planktonic zones; these zones correlated with the international schemes for biozones in the subtropical areas and the Mediterranean regions.

Current legal regime for environmental impact assessment in areas beyond national jurisdiction and its future approaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Deqiang; Coastal and Ocean Management Institute, Xiamen University, 361102; Fang, Qinhua, E-mail: qhfang@xmu.edu.cn

In 2004, the United Nations launched an Ad Hoc Open-ended Informal Working Group to study issues relating to the conservation and sustainable use of marine biological diversity in areas beyond national jurisdiction. Since then, the topic of governing marine areas beyond national jurisdiction (ABNJ) has been widely discussed by politicians, policy makers and scholars. As one of management tools to protect marine biodiversity in ABNJ, environmental impact assessment (EIA) has been widely recognized and accepted by the international community, however, the biggest challenge is how to effectively implement the EIA regime in ABNJ. This paper explores the impacts of anthropogenicmore » activities in ABNJ on marine ecosystems, reviews the existing legal regime for EIA in ABNJ and discusses possible measures to strengthen the implementation of EIA in ABNJ. - Highlights: • We identify human activities in ABNJ and their impacts on marine ecosystems. • We analyze the characters and gaps of the existing legal regime for EIA in ABNJ. • We analyze the pros and cons of alternative approaches of EIA in ABNJ.« less

Marine debris in beaches of the Southwestern Atlantic: An assessment of their abundance and mass at different spatial scales in northern coastal Argentina.

PubMed

Becherucci, Maria Eugenia; Rosenthal, Alan Federico; Seco Pon, Juan Pablo

2017-06-15

Argentina is currently undergoing an intensive development of coastal-oriented tourism due to the temperate climate and coastal sceneries of the Southwestern Atlantic and particularly its wide ocean-open sandy beaches, which may turn into an important contributor of marine debris to the beaches. This study was designed to assess at four spatial scales (i) the variation of the abundance and mass of marine debris and (ii) the composition and sources of these items in sandy-tourist beaches of coastal zones of the province of Buenos Aires, in northern Argentina. The abundance and mass of marine debris shifted between sampling localities (separated by ~1.5×10 5 m) and beaches (~3×10 4 m). Debris was primarily from recreational and fishing activities and over 20mm in size. Tackling the complications associated with marine debris in northern Argentina may include intensive educational and advertising campaigns oriented chiefly to beach users and fisherman. Copyright © 2017. Published by Elsevier Ltd.

Evolution of Sulfur Isotopes and Oceanic Oxygenation Recorded in a Neoproterozoic Cap Carbonate From the Chaidam Block, China

NASA Astrophysics Data System (ADS)

Shen, B.; Xiao, S.; Kaufman, A.; Zhou, C.

2006-12-01

Neoproterozoic successions in the Chaidam Block, northwestern China, include the Hongtiegou Formation, which consists of a 20-meter thick, reddish diamictite with widespread dropstones and outsized clasts. The age of the Hongtiegou diamictite is unknown, but recent biostratigraphic correlations support a Neoproterozoic assignment. The glacial deposit is immediately overlain by a 5-meter thick carbonate of the basal Zhoujieshan Formation, which we interpret as a classic post-glacial cap carbonate. However, carbon isotope compositions of samples from this unit are near zero or slightly positive (up to ~ 2‰), which contrasts with the strongly negative (ca. -5‰) values recorded in the basal portions of most other post-glacial Neoproterozoic caps. Trace sulfate concentrations in samples of the carbonate are notably high, with an average of 366 ± 266 ppm. In the lower 2.5 meters of the Zhoujieshan cap (stage I) sulfur isotope compositions of both carbonate associated sulfate (CAS) and sulfides isolated from the same sample are indistinguishable from each other, and rise in concert by over 10% to values around +22‰. Above this level (stage II), 34S abundances of sulfides continue to increase to a peak of +27‰, but CAS values fall back to ~15‰. As a result isotopic differences between sulfides and sulfates are near zero in stage I and around 10% in stage II. The evolution of both systems in the lower half of the deposit suggests that seawater sulfate must have evolved to progressively heavier 34S compositions, and that sulfate in pore waters ¨C where sulfate reducing bacteria were active ¨C was quantitatively reduced to pyrite. This might result from the progressive distillation of sulfate from seawater by an enhanced rain of carbonate, in addition to bacterial reduction of sulfate, in the glacial aftermath. The anomalous isotope systematics of stage II are difficult to model, but might signal a new source and higher abundances of oceanic sulfate, based on increasing CAS concentration through the cap carbonate. In this case, CAS would reflect the buffered pool of oceanic sulfate, but the higher concentrations of sulfate trapped in pore waters would be distilled and through Rayleigh distillation the instantaneous sulfide product could become enriched in 34S relative to the starting sulfate. This Rayleigh distillation signature may be preserved in Stage II cap carbonate. Alternatively, continuing post-glacial stratification and Rayleigh distillation of 34S-enriched anoxic deepwater mass relict from the glaciation (Hurtgen et al., 2006, EPSL, 245:551¨C570) may be responsible for the heavy ¦Ä34Ssulfide values record in the cap carbonate. In sum, these results may indicate a progressive increase in oceanic sulfate due to a post-glacial increase in the oxidation state of seawater.

Reciprocal transplants support a plasticity-first scenario during colonisation of a large hyposaline basin by a marine macro alga.

PubMed

Johansson, Daniel; Pereyra, Ricardo T; Rafajlović, Marina; Johannesson, Kerstin

2017-04-05

Establishing populations in ecologically marginal habitats may require substantial phenotypic changes that come about through phenotypic plasticity, local adaptation, or both. West-Eberhard's "plasticity-first" model suggests that plasticity allows for rapid colonisation of a new environment, followed by directional selection that develops local adaptation. Two predictions from this model are that (i) individuals of the original population have high enough plasticity to survive and reproduce in the marginal environment, and (ii) individuals of the marginal population show evidence of local adaptation. Individuals of the macroalga Fucus vesiculosus from the North Sea colonised the hyposaline (≥2-3‰) Baltic Sea less than 8000 years ago. The colonisation involved a switch from fully sexual to facultative asexual recruitment with release of adventitious branches that grow rhizoids and attach to the substratum. To test the predictions from the plasticity-first model we reciprocally transplanted F. vesiculosus from the original population (ambient salinity 24‰) and from the marginal population inside the Baltic Sea (ambient salinity 4‰). We also transplanted individuals of the Baltic endemic sister species F. radicans from 4 to 24‰. We assessed the degree of plasticity and local adaptation in growth and reproductive traits after 6 months by comparing the performance of individuals in 4 and 24‰. Branches of all individuals survived the 6 months period in both salinities, but grew better in their native salinity. Baltic Sea individuals more frequently developed asexual traits while North Sea individuals initiated formation of receptacles for sexual reproduction. Marine individuals of F. vesiculosus are highly plastic with respect to salinity and North Sea populations can survive the extreme hyposaline conditions of the Baltic Sea without selective mortality. Plasticity alone would thus allow for an initial establishment of this species inside the postglacial Baltic Sea at salinities where reproduction remains functional. Since establishment, the Baltic Sea populations have evolved adaptations to extreme hyposaline waters and have in addition evolved asexual recruitment that, however, tends to impede local adaptation. Overall, our results support the "plasticity-first" model for the initial colonisation of the Baltic Sea by Fucus vesiculosus.

Sea ice cover variability and river run-off in the western Laptev Sea (Arctic Ocean) since the last 18 ka

NASA Astrophysics Data System (ADS)

Hörner, T.; Stein, R.; Fahl, K.; Birgel, D.

2015-12-01

Multi-proxy biomarker measurements were performed on two sediment cores (PS51/154, PS51/159) with the objective reconstructing sea ice cover (IP25, brassicasterol, dinosterol) and river-runoff (campesterol, β-sitosterol) in the western Laptev Sea over the last 18 ka with unprecedented temporal resolution. The sea ice cover varies distinctly during the whole time period. The absence of IP25 during 18 and 16 ka indicate that the western Laptev Sea was mostly covered with permanent sea ice (pack ice). However, a period of temporary break-up of the permanent ice coverage occurred at c. 17.2 ka (presence of IP25). Very little river-runoff occurred during this interval. Decreasing terrigenous (riverine) input and synchronous increase of marine produced organic matter around 16 ka until 7.5 ka indicate the gradual establishment of a marine environment in the western Laptev Sea related to the onset of the post-glacial transgression of the shelf. Strong river run-off and reduced sea ice cover characterized the time interval between 15.2 and 12.9 ka, including the Bølling/Allerød warm period (14.7 - 12.9 ka). Moreover, the DIP25 Index (ratio of HBI-dienes and IP25) might document the presence of Atlantic derived water at the western Laptev Sea shelf area. A sudden return to severe sea ice conditions occurred during the Younger Dryas (12.9 - 11.6 ka). This abrupt climate change was observed in the whole circum-Arctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). At the onset of the Younger Dryas, a distinct alteration of the ecosystem (deep drop in terrigenous and phytoplankton biomarkers) may document the entry of a giant freshwater plume, possibly relating to the Lake Agassiz outburst at 13 ka. IP25 concentrations increase and higher values of the PIP25 Index during the last 7 ka reflect a cooling of the Laptev Sea spring season. Moreover, a short-term variability of c. 1.5 thousand years occurred during the last 12 ka, most probably following Bond Cycles.

Post-glacial sea-level history for NE Ireland (Belfast Lough) based on offshore evidence

NASA Astrophysics Data System (ADS)

Quinn, R.; Plets, R. M.; Callard, L.; Cooper, A.; Long, A. J.; Belknap, D. F.; Edwards, R.; Jackson, D.; Kelley, J. T.; Long, D.; Milne, G. A.; Monteys, X.

2013-12-01

Glacio-isostatic adjustment (GIA) models suggest a complex relative sea-level (RSL) pattern around the Irish Sea Basin after the Last Glacial Maximum (LGM), with modelled sea-level lowstands ranging from -12 m in the north to greater than -60 m in the south of the Basin. However, these GIA models are poorly constrained by observational data offshore. Belfast Lough, on the NE coast of Ireland, is one of seven sites chosen to investigate this complex RSL history as part of the project ';Late Glacial Sea level minima in the Western British Isles' (NERC NE/H024301/1). Belfast Lough was chosen as one of the candidate sites on the basis of location (at the northern end of the Irish Sea Basin), sedimentary environment (grossly depositional) and the fact that the lowstand predicted for the Belfast Lough area by a recent version of the GIA model (-16.5 m) differs significantly from the (limited) extant observational data, which interprets the lowstand at -30 m. In 2011 and 2012 we gathered new multi-beam echo-sounder data, >200 km trackline pinger- and boomer- seismic reflection data and 46 vibrocores in Belfast Lough. Radiocarbon dating and palaeoenvironmental analysis are used to constrain the interpretation of the seismic and sediment data. Five seismo-stratigraphic units are interpreted, with a distinct erosional surface between U3 and U4 interpreted as a transgressive surface associated with sea level rise post-dating a RSL lowstand. Foraminiferal evidence indicates an increase in marine species (from lagoonal/estuarine to fully marine) from U4 to U5. Integration of the seismic and core data indicate an erosional event prior to 12.7 cal yr BP resulting in a planated surface in the inner Lough and wave-eroded drumlins at the mouth of the Lough between -15 and -22 m, interpreted as a possible slowstand. On the basis of seismic evidence in the outer Lough, an as yet undated lowstand at -42 m is tentatively interpreted to pre-date this stillstand. These results will be used to tune the Earth and ice model parameters in a new run of the GIA model.

Post-glacial sea-level history for NE Ireland (Belfast Lough) based on offshore evidence

NASA Astrophysics Data System (ADS)

Quinn, Rory; Plets, Ruth; Callard, Louise; Cooper, Andrew; Antony, Long; Daniel, Belknap; Robin, Edwards; Derek, Jackson; Joseph, Kelley; David, Long; Glenn, Milne; Xavier, Monteys

2014-05-01

Glacio-isostatic adjustment (GIA) models suggest a complex relative sea-level (RSL) pattern around the Irish Sea Basin after the Last Glacial Maximum (LGM), with modelled sea-level lowstands ranging from -12 m in the north to greater than -60 m in the south of the Basin. However, these GIA models are poorly constrained by observational data offshore. Belfast Lough, on the NE coast of Ireland, is one of seven sites chosen to investigate this complex RSL history as part of the project 'Late Glacial Sea level minima in the Western British Isles' (NERC NE/H024301/1). Belfast Lough was chosen as one of the candidate sites on the basis of location (at the northern end of the Irish Sea Basin), sedimentary environment (grossly depositional) and the fact that the lowstand predicted for the Belfast Lough area by a recent version of the GIA model (-16.5 m) differs significantly from the (limited) extant observational data, which interprets the lowstand at -30 m. In 2011 and 2012 we gathered new multi-beam echo-sounder data, >200 km trackline pinger- and boomer- seismic reflection data and 46 vibrocores in Belfast Lough. Radiocarbon dating and palaeoenvironmental analysis are used to constrain the interpretation of the seismic and sediment data. Five seismo-stratigraphic units are interpreted, with a distinct erosional surface between U3 and U4 interpreted as a transgressive surface associated with sea level rise post-dating a RSL lowstand. Foraminiferal evidence indicates an increase in marine species (from lagoonal/estuarine to fully marine) from U4 to U5. Integration of the seismic and core data indicate an erosional event prior to 12.7 cal yr BP resulting in a planated surface in the inner Lough and wave-eroded drumlins at the mouth of the Lough between -15 and -22 m, interpreted as a possible slowstand. On the basis of seismic evidence in the outer Lough, an as yet undated lowstand at -42 m is tentatively interpreted to pre-date this stillstand. These results will be used to tune the Earth and ice model parameters in a new run of the GIA model.

Land-Marine Paleoseismic Integration for the Northern Cascadia Margin, USA

NASA Astrophysics Data System (ADS)

Goldfinger, C.; Galer, S.; Beeson, J. W.; Hamilton, T. S.; Black, B.; Romsos, C. G.; Nelson, C. H.; Morey, A. E.

2015-12-01

New and archive cores (N=70), bathymetric, backscatter and sub-bottom data from the Washington margin reveal patterns of Holocene sediment transport and deposition. Barkley, Nitinat, Juan de Fuca (JDF), Quillayute, Grays, Guide, and Willapa Canyons each have different post-glacial mechanisms of loading and dispersal of sediment via turbidity currents. In high-stand conditions, the northern canyons, Barkley, Nitinat, JDF, and Quillayute are mostly relict systems. The remaining canyons, Quinault, Grays, Guide, and Willapa, are recharged to varying degrees by northward transport of Columbia River derived sediment. All systems are nonetheless active conduits for turbidity currents during the Holocene. Sedimentologic and CT analyses, supported by radiocarbon ages, micropaleontology, and the Mazama Ash show that the Holocene sedimentary sequence consists of a series of sand to mud turbidites in the active portions of all systems, interbedded with hemipelagic sediment. The relict systems are finer grained, commonly not visually detected, with Holocene turbidite counts the same as recharged systems. Use of 1960's core sketches (Atwater) fails to capture the full record, as noted by Barnard (1973). Hydrodynamic models and heavy mineral distributions show that the northern canyon systems (Barkley, Nitinat, JDF, Quillayute) are independent of the southern systems, (Quinault, Guide, Grays, Willapa) during the Holocene. Best fitting flow inversions suggest turbidity currents range in height from 80-170 m, consistent with earlier work and backscatter observations. Mass balancing suggests sediment supplied to the slope canyons and abyssal channels is 4-6 times greater than supplied by recharge to the canyon heads by external sources, strongly indicating autogenic sourcing by earthquakes. Turbidite deposition off Washington is not very sensitive to either sediment supply or slope angle. Lithostratigraphic correlation and age models of Holocene turbidite sequences suggests deposition of ~ 20 Holocene turbidites in most parts of the Canyon systems, with little variation. The explanation most consistent with the data is triggering by a series of 18-20 Holocene earthquakes, in agreement temporal and lithostratigraphic linkages to new marine sites in Canada, as well and land paleoseismic data.

Glacio-isostasy and Glacial Ice Load at Law Dome, Wilkes Land, East Antarctica

NASA Astrophysics Data System (ADS)

Goodwin, Ian D.; Zweck, Christopher

2000-05-01

The Holocene sea-level high stand or "marine limit" in Wilkes Land, East Antarctica, reached ˜30 m above present sea level at a few dispersed sites. The most detailed marine limit data have been recorded for the Windmill Islands and Budd Coast at the margin of the Law Dome ice cap, a dome of the East Antarctic Ice Sheet (EAIS). Relative sea-level lowering of 30 m and the associated emergence of the Windmill Islands have occurred since 6900 14C (corr.) yr B.P. Numerical modeling of the Earth's rheology is used to determine the glacio-isostatic component of the observed relative sea-level lowering. Glaciological evidence suggests that most of EAIS thickening occurred around its margin, with expansion onto the continental shelf. Consequently, a regional ice history for the last glacial maximum (LGM) was applied in the glacio-isostatic modeling to test whether the observed relative sea-level lowering was primarily produced by regional ice-sheet changes. The results of the modeling indicate that the postglacial (13,000 to 8000 14C yr B.P) removal of an ice load of between 770 and 1000 m from around the margin of the Law Dome and adjacent EAIS have produced the observed relative sea-level lowering. Such an additional ice load would have been associated with a 40- to 65-km expansion of the Law Dome to near the continental shelf break, together with a few hundred meters of ice thickening on the adjoining coastal slope of the EAIS up to 2000 m elevation. Whereas the observed changes in relative sea level are shown to be strongly influenced by regional ice sheet changes, the glacio-isostatic response at the Windmill Islands results from a combination of regional and, to a lesser extent, Antarctic-wide effects. The correspondence between the Holocene relative sea-level lowering interpreted at the margin of the Law Dome and the lowering interpreted along the remainder of the Wilkes Land and Oates Land coasts (105°-160° E) suggests that a similar ice load of up to 1000 m existed along the EAIS margin between Wilkes Land and Oates Land.

Seismic and gravity investigations of the shallow (upper 1 km) hanging wall of the Alpine Fault in the vicinity of the Whataroa River, New Zealand

NASA Astrophysics Data System (ADS)

Kovacs, A.; Gorman, A. R.; Lay, V.; Buske, S.

2013-12-01

Paleoseismic evidence from the vicinity of the plate-bounding Alpine Fault on New Zealand's South Island suggests that earthquakes of magnitude 7.9 occur every 200-400 years, with the last earthquake occurring in AD 1717. No human observations of this event are recorded. Therefore, the Deep Fault Drilling Project 2 (DFDP-2) drill hole, which is planned for 2014 on the hanging wall of the Alpine Fault in the Whataroa Valley, provides a critical opportunity to study the behavior of this transpressive plate boundary late in its seismogenic cycle. New seismic and gravity data collected since 2011 have been analyzed to assist with the positioning of the drill hole in this glacial valley that provides rare low-elevation access to the hanging wall of the Alpine Fault. The WhataDUSIE controlled-source seismic project, led by researchers from the University of Otago (New Zealand), TU Bergakademie Freiberg (Germany) and the University of Alberta (Canada), provided relatively high-resolution coverage (4-8 m geophone spacing, 25-100 m shot spacing) along a 5-km-long profile across the Alpine Fault in the Whataroa Valley. This work has been supplemented by focused hammer-seismic studies and gravity data collection in the valley. The former targets surface layer properties, whereas the latter targets the depth to the base of the glacially carved paleovalley. In positioning DFDP-2, an understanding of the nature of overburden and valley-fill sediments is critical for drilling design. A velocity model has been developed for the valley based on refraction analysis of the WhataDUSIE and hammer-seismic data combined with a ray-theoretical travel-time tomography (RAYINVR) image of the shallow (uppermost 1 km or so) part of the hanging wall of the Alpine Fault. The model shows that the glacial valley, which presumably was last scoured by ice at the Last Glacial Maximum, has been filled with 200-350 m of post-glacial sediments and outwash gravels. The hanging-wall rocks into which the valley was cut are presumed to be mylonitized Alpine Schist. Considering uplift rates of 6-10 mm/a on the hanging wall of the fault and a glacial withdrawal date of 10,000 years before present (i.e., 60-100 m of uplift since the ice vacated the valley), the floor of the valley would have been as deep as about 350 m below sea level at the time that the ice withdrew (given the current elevation of ~100 m on the valley floor). Basal sediments in the valley could therefore be either marine (if the valley was open to the ocean) or lacustrine (if the valley was isolated from the open ocean by elevated footwall rocks along the west coast of the South Island). Once the original water body in the valley was filled, sediments would accumulate as outwash gravels above sea level.

Natural variability of pCO2 and pH in the Atlantic and Pacific coastal margins of the U.S

NASA Astrophysics Data System (ADS)

Sutton, A. J.; Sabine, C. L.; Feely, R. A.; Newton, J.; Salisbury, J.; Vandemark, D. C.; Musielewicz, S. B.; Maenner-Jones, S.; Bott, R.; Lawrence-Slavas, N.

2011-12-01

The discovery that seawater chemistry is changing as a result of carbon dioxide (CO2) emissions, referred to as "ocean acidification", has prompted a large effort to understand how this changing chemistry will impact marine life. Changes in carbon chemistry have been documented in the open ocean; however, in dynamic coastal systems where many marine species live, ocean acidification and the natural biogeochemical variability that organisms are currently exposed to are poorly quantified. In 2010 we began equipping coastal moorings currently measuring pCO2 with pH and other biogeochemical sensors to measure ocean acidification parameters at 3 hour intervals in the surface water. Here we present the magnitude and diurnal to seasonal variability of pCO2 and pH during the first year of observations at 2 sites in the Atlantic and Pacific coastal margins of the U.S.: the Gulf of Maine and outer coast of Washington state. Both the magnitude and range of pCO2 and pH values were much greater at the coastal moorings compared to the open ocean mooring at Ocean Station Papa in the North Pacific and also varied between the two coastal mooring sites. We observed maximum pCO2 values in coastal waters exceeding predicted values for the open ocean at 2x pre-industrial CO2 levels. The range of pCO2 and pH values during this time series was approximately 4 times the range observed at open ocean mooring Papa (2007-2011 time series). In many cases, large variance was observed at short time scales, with values fluctuating more than 200 μatm pCO2 and 0.2 pH between 3-hour cycles. These types of observations are critical for understanding how ocean acidification will manifest in naturally dynamic coastal systems and for informing the experimental design of species response studies that aim to mimic carbon chemistry experienced by coastal marine organisms.

Terrestrial and marine records of climatic and environmental changes during the Pliocene in subtropical Florida

USGS Publications Warehouse

Willard, D.A.; Cronin, T. M.; Ishman, S.E.; Litwin, R.J.

1993-01-01

Pollen, ostracode, and benthic foraminifer assemblages deposited during sea-level highstands in subtropical Florida record a climate change during the period 4.5-1.0 Ma. Before 3.5 Ma, open-shelf marine faunas and pollen assemblages with abundant Pinus, Quercus, Fagus, Carya, and nonarboreal pollen were present, indicating cooler conditions than today. From ~3.5 to 1.0 Ma, marine and terrestrial records indicate warmer conditions, similar to those existing in south Florida today. Combined with evidence for much warmer than modern conditions at high latitudes, these data suggest that increased poleward oceanic heat transport, possibly related to the emergence of the Central American isthmus between ~3.5 and 2.5 Ma, was a major influence on mid-Pliocene warmth. -Authors

Ophiuroids Discovered in the Middle Triassic Hypersaline Environment

PubMed Central

Salamon, Mariusz A.; Niedźwiedzki, Robert; Lach, Rafał; Brachaniec, Tomasz; Gorzelak, Przemysław

2012-01-01

Echinoderms have long been considered to be one of the animal phyla that is strictly marine. However, there is growing evidence that some recent species may live in either brackish or hypersaline environments. Surprisingly, discoveries of fossil echinoderms in non-(open)marine paleoenvironments are lacking. In Wojkowice Quarry (Southern Poland), sediments of lowermost part of the Middle Triassic are exposed. In limestone layer with cellular structures and pseudomorphs after gypsum, two dense accumulations of articulated ophiuroids (Aspiduriella similis (Eck)) were documented. The sediments with ophiuroids were formed in environment of increased salinity waters as suggested by paleontological, sedimentological, petrographical and geochemical data. Discovery of Triassic hypersaline ophiuroids invalidates the paleontological assumption that fossil echinoderms are indicators of fully marine conditions. Thus caution needs to be taken when using fossil echinoderms in paleoenvironmental reconstructions. PMID:23185442

Comanagement practices enhance fisheries in marine protected areas.

PubMed

Guidetti, Paolo; Claudet, Joachim

2010-02-01

Fishing activities worldwide have dramatically affected marine fish stocks and ecosystems. Marine protected areas (MPAs) with no-take zones may enhance fisheries, but empirical evidence of this is scant. We conducted a 4-year survey of fish catches around and within an MPA that was previously fully closed to fishing and then partially reopened under regulated comanaged fishing. In collaboration with the fishers and the MPA authority, we set the fishing effort and selected the gear to limit fishing impact on key fish predators, juvenile fish stage, and benthic communities and habitats. Within an adaptive comanagement framework, fishers agreed to reduce fishing effort if symptoms of overfishing were detected. We analyzed the temporal trends of catch per unit of effort (CPUE) of the whole species assemblages and CPUE of the four most valuable and frequent species observed inside the opened buffer zone and outside the MPA investigated. After the comanaged opening, CPUE first declined and then stabilized at levels more than twice that of catches obtained outside the MPA. Our results suggest that working closely with fishers can result in greater fisheries catches. Partial protection of coastal areas together with adaptive comanagement involving fishers, scientists, and managers can effectively achieve conservation and fishery management goals and benefit fishing communities and alleviate overfishing.

Effects of offshore wind farms on marine wildlife—a generalized impact assessment

NASA Astrophysics Data System (ADS)

Bergström, Lena; Kautsky, Lena; Malm, Torleif; Rosenberg, Rutger; Wahlberg, Magnus; Åstrand Capetillo, Nastassja; Wilhelmsson, Dan

2014-03-01

Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning.

Water's Way at Sleepers River watershed - revisiting flow generation in a post-glacial landscape, Vermont USA

Treesearch

James B. Shanley; Stephen D. Sebestyen; Jeffrey J. McDonnell; Brian L. McGlynn; Thomas Dunne

2015-01-01

The Sleepers River Research Watershed (SRRW) in Vermont, USA, has been the site of active hydrologic research since 1959 and was the setting where Dunne and Black demonstrated the importance and controls of saturation-excess overland flow (SOF) on streamflow generation. Here, we review the early studies from the SRRW and show how they guided our conceptual approach to...

78 FR 17428 - Notice of Open Public Meetings for the National Park Service Alaska Region's Subsistence Resource...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-21

... Purpose 6. Commission Membership Status 7. SRC Chair and SRC Members' Reports 8. Superintendent's Report 9... a. Red Dog Road Study Update b. Marine Resources (Seals/Walrus) 11. Federal Subsistence Board Update...

Antifungal cyclic peptides from the marine sponge Microscleroderma herdmani

USDA-ARS?s Scientific Manuscript database

Screening natural product extracts from National Cancer Institute Open Repository for antifungal discovery afforded hits for bioassay-guided fractionation. Upon LC-MS analysis of column fractions with antifungal activities to generate information on chemical structure, two new cyclic hexapeptides, m...

Height Connections and Land Uplift Rates in West-Estonian Archipelago

NASA Astrophysics Data System (ADS)

Jürgenson, H.; Liibusk, A.; Kall, T.

2012-04-01

Land uplift rates are largest in the western part of Estonia. The uplift is due to post-glacial rebound. In 2001-2011, the Estonian national high-precision levelling network was completely renewed and levelled. This was the third precise levelling campaign in the re-gion. The first one had taken place before the Second World War and the second one in the 1950s. The Estonian mainland was connected with the two largest islands (Saaremaa and Hiiumaa) in the west-Estonian archipelago using the water level monitoring (hydrody-namic levelling) method. Three pairs of automatic tide gauges were installed on opposite coasts of each waterway. The tide gauges were equipped with piezoresistive pressure sen-sors. This represented the first use of such kind of equipment in Estonia. The hydrodynamic levelling series span up to two calendar years. Nevertheless, the obtained hydrodynamic levelling results need to be additionally verified using alternative geodetic methods. The obtained results were compared with the previous high-precision levelling data from the 1960s and 1970s. As well, the new Estonian gravimetric geoid model and the GPS survey were used for GPS-levelling. All the three methods were analyzed, and the preliminary results coincided within a 1-2 cm margin. Additionally, the tide gauges on the mainland and on both islands were connected using high-precision levelling. In this manner, three hydrodynamic and three digital levelling height differences formed a closed loop with the length of 250 km. The closing error of the loop was less than 1 cm. Finally, the Fennoscandian post-glacial rebound was determined from repeated levelling as well as from repeated GPS survey. The time span between the two campaigns of the first-order GPS survey was almost 13 years. According to new calculations, the relative land uplift rates within the study area reached up to +2 mm/year. This is an area with a rela-tively small amount of input data for the Nordic models. In addition, a comparison with the Fennoscandian land uplift model NKG2005LU is presented. The results coincided with this model within a 1-mm range. Keywords: hydrodynamic levelling, post-glacial land uplift, GPS-levelling, West-Estonian archipelago.

Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)

NASA Astrophysics Data System (ADS)

Poiré, Antoine G.; Lajeunesse, Patrick; Normandeau, Alexandre; Francus, Pierre; St-Onge, Guillaume; Nzekwe, Obinna P.

2018-04-01

High-resolution swath bathymetry imagery allowed mapping in great detail the sublacustrine geomorphology of lakes Pentecôte, Walker and Pasteur, three deep adjacent fjord-lakes of the Québec North Shore (eastern Canada). These sedimentary basins have been glacio-isostatically uplifted to form deep steep-sided elongated lakes. Their key geographical position and limnogeological characteristics typical of fjords suggest exceptional potential for long-term high-resolution paleoenvironmental reconstitutions. Acoustic subbottom profiles acquired using a bi-frequency Chirp echosounder (3.5 & 12 kHz), together with cm- and m-long sediment core data, reveal the presence of four acoustic stratigraphic units. The acoustic basement (Unit 1) represents the structural bedrock and/or the ice-contact sediments of the Laurentide Ice Sheet and reveals V-shaped bedrock valleys at the bottom of the lakes occupied by ice-loaded sediments in a basin-fill geometry (Unit 2). Moraines observed at the bottom of lakes and in their structural valleys indicate a deglaciation punctuated by short-term ice margin stabilizations. Following ice retreat and their isolation, the fjord-lakes were filled by a thick draping sequence of rhythmically laminated silts and clays (Unit 3) deposited during glaciomarine and/or glaciolacustrine settings. These sediments were episodically disturbed by mass-movements during deglaciation due to glacial-isostatic rebound. AMS 14C dating reveal that the transition between deglaciation of the lakes Pentecôte and Walker watersheds and the development of para- and post-glacial conditions occurred around 8000 cal BP. The development of the lake-head river delta plain during the Holocene provided a constant source of fluvial sediment supply to the lakes and the formation of turbidity current bedforms on the sublacustrine delta slopes. The upper sediment succession (i.e., ∼4-∼6.5 m) consists of a continuous para-to post-glacial sediment drape (Unit 4) that contains laminated and massive sediment and series of Rapidly Deposited Layers. These results allow establishing a conceptual model of how a glaciated coastal fjord evolves during and after deglaciation in a context of rapid glacio-isostatically induced forced regression.

Paleo-climatic and paleo-environmental evolution of the Neoproterozoic basal sedimentary cover on the Río de La Plata Craton, Argentina: Insights from the δ13C chemostratigraphy

NASA Astrophysics Data System (ADS)

Gómez-Peral, Lucía E.; Sial, Alcides N.; Arrouy, M. Julia; Richiano, Sebastián; Ferreira, Valderez P.; Kaufman, Alan J.; Poiré, Daniel G.

2017-05-01

The Sierras Bayas Group of the Tandilia System constitutes the Neoproterozoic sedimentary cover of the Río de La Plata Craton in Argentina that accumulated amid the breakup of the Rodinia supercontinent and subsequent assembly of Gondwanaland. Evidence for glaciation in the Villa Mónica Formation (VMF) at the base of the succession comes in the form of iron-rich laminated sediments containing dropstones composed predominantly of basement crystalline rocks and quartzites that, are sequentially overlain by a phosphatic mudstone and a 40 m thick stromatolitic dolomite. Subtidal facies preserve columnar forms similar to post-glacial tubestone stromatolites seen in the Neoproterozoic records. These morphologies suggest rapid growth associated with elevated seawater alkalinity and high rates of carbonate accumulation records. The VMF dolomites in our four studied sections near Olavarría-Sierras Bayas area reveal a pronounced negative-to-positive δ13C up section that is similarly to these cap carbonates and others worldwide. Our sedimentological and geochemical study of the VMF sections reveal consistent carbon and oxygen isotope trends that may be useful for detailed intra-basinal correlations. Samples of the VMF fabric-retentive dolomite preserve an unusually narrow range of non-radiogenic strontium isotopic compositions (0.7068 to 0.7070) that are consistent with Cryogenian limestone facies in the potential Namibian and Brazilian equivalents. Exceptional preservation of 87Sr/86Sr compositions suggest the possibility of primary dolomite precipitation in post-glacial seawater, and furthermore that REE patterns and distributions may yield similar insights to redox conditions in the depositional basin. In particular, the VMF dolomites reveal depleted LREE abundances, a negative Ce anomaly, positive La and Gd anomalies, and low Y/Ho values. As a whole, these observations suggest oxidizing post-glacial seawater conditions associated with significant freshwater inputs into the basin. Global warming and increases in primary productivity and organic carbon burial linked to the buildup of oxygen, the positive δ13C trend and the increase in stromatolite biodiversity in the VMF.

Modelling the effects of ice-sheet activity on CO2 outgassing by Icelandic volcanoes

NASA Astrophysics Data System (ADS)

Armitage, J. J.; Ferguson, D.; Petersen, K. D.; Creyts, T. T.

2017-12-01

Glacial cycles may play a significant role in mediating the flux of magmatic CO2 between the Earth's mantle and atmosphere. In Iceland, it is thought that late-Pleistocene deglaciation led to a significant volcanic pulse, evidenced by increased post-glacial lava volumes and changes in melt chemistry consistent with depressurization. Investigating the extent to which glacial activity may have affected volcanic CO2 emissions from Iceland, and crucially over what timescale, requires detailed knowledge of how the magma system responded to the growth and collapse of the ice-sheet before and after the LGM. To investigate this, we coupled a model of magma generation and transport with a history of ice-sheet activity. Our results show that the emplacement and removal of the LGM ice-sheet likely led to two significant pulses of magmatic CO2. The first, and most significant of these, is associated with ice-sheet growth and occurs as the magma system recovers from glacial loading. This recovery happens from the base of the melting region upwards, producing a pulse of CO2 rich magma that is predicted to reach the surface around 20 ka after the loading event, close in time to the LGM. The second peak in CO2 output occurs abruptly following deglaciation as a consequence of increased rates of melt generation and transport in the shallow mantle. Although these post-glacial melts are relatively depleted in CO2, the increase in magma flux leads to a short-lived period of elevated CO2 emissions. Our results therefore suggest a negative feedback, whereby ice-sheet growth produces a delayed pulse of magmatic CO2, which, in addition to increased geothermal heat flux, may contribute towards driving deglaciation, which itself then causes further magmatism and CO2 outgassing. This model is consistent with the seismic structure of the asthenosphere below Iceland, and the established compositional and volumetric trends for sub- and post-glacial volcanism in Iceland. These trends show that the earliest subglacial events involved small volumes of enriched melts, while eruptions that were synchronous with or immediately followed deglaciation involved larger volumes of more depleted melts.

Regional assessment of concentrations and sources of pharmaceutically active compounds, pesticides, nitrate, and E. coli in post-glacial aquifer environments (Canada).

PubMed

Saby, Marion; Larocque, Marie; Pinti, Daniele L; Barbecot, Florent; Gagné, Sylvain; Barnetche, Diogo; Cabana, Hubert

2017-02-01

There is growing concern worldwide about the exposure of groundwater resources to pharmaceutically active compounds (PhACs) and agricultural contaminants, such as pesticides, nitrate, and Escherichia coli. For regions with a low population density and an abundance of water, regional contamination assessments are not carried out systematically due to the typically low concentrations and high costs of analyses. The objectives of this study were to evaluate regional-scale contaminant distributions in untreated groundwater in a rural region of Quebec (Canada). The geological and hydrogeological settings of this region are typical of post-glacial regions around the world, where groundwater flow can be complex due to heterogeneous geological conditions. A new spatially distributed Anthropogenic Footprint Index (AFI), based on land use data, was developed to assess surface pollution risks. The Hydrogeochemical Vulnerability Index (HVI) was computed to estimate aquifer vulnerability. Nine wells had detectable concentrations of one to four of the 13 tested PhACs, with a maximum concentration of 116ng·L -1 for benzafibrate. A total of 34 of the 47 tested pesticides were detected in concentrations equal to or greater than the detection limit, with a maximum total pesticide concentration of 692ng·L -1 . Nitrate concentrations exceeded 1mg·L -1 N-NO 3 in 15.3% of the wells, and the Canadian drinking water standard was exceeded in one well. Overall, 13.5% of the samples had detectable E. coli. Including regional-scale sources of pollutants to the assessment of aquifer vulnerability with the AFI did not lead to the identification of contaminated wells, due to the short groundwater flow paths between recharge and the sampled wells. Given the occurrence of contaminants, the public health concerns stemming from these new data on regional-scale PhAC and pesticide concentrations, and the local flow conditions observed in post-glacial terrains, there is a clear need to investigate the sources and behaviours of local-scale pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

Reduced plant water status under sub-ambient pCO2 limits plant productivity in the wild progenitors of C3 and C4 cereals

PubMed Central

Cunniff, Jennifer; Charles, Michael; Jones, Glynis; Osborne, Colin P.

2016-01-01

Background and Aims The reduction of plant productivity by low atmospheric CO2 partial pressure (pCO2) during the last glacial period is proposed as a limiting factor for the establishment of agriculture. Supporting this hypothesis, previous work has shown that glacial pCO2 limits biomass in the wild progenitors of C3 and C4 founder crops, in part due to the direct effects of glacial pCO2 on photosynthesis. Here, we investigate the indirect role of pCO2 mediated via water status, hypothesizing that faster soil water depletion at glacial (18 Pa) compared to post-glacial (27 Pa) pCO2, due to greater stomatal conductance, feeds back to limit photosynthesis during drying cycles. Methods We grew four wild progenitors of C3 and C4 crops at glacial and post-glacial pCO2 and investigated physiological changes in gas exchange, canopy transpiration, soil water content and water potential between regular watering events. Growth parameters including leaf area were measured. Key Results Initial transpiration rates were higher at glacial pCO2 due to greater stomatal conductance. However, stomatal conductance declined more rapidly over the soil drying cycle in glacial pCO2 and was associated with decreased intercellular pCO2 and lower photosynthesis. Soil water content was similar between pCO2 levels as larger leaf areas at post-glacial pCO2 offset the slower depletion of water. Instead the feedback could be linked to reduced plant water status. Particularly in the C4 plants, soil–leaf water potential gradients were greater at 18 Pa compared with 27 Pa pCO2, suggesting an increased ratio of leaf evaporative demand to supply. Conclusions Reduced plant water status appeared to cause a negative feedback on stomatal aperture in plants at glacial pCO2, thereby reducing photosynthesis. The effects were stronger in C4 species, providing a mechanism for reduced biomass at 18 Pa. These results have added significance when set against the drier climate of the glacial period. PMID:27578764

Sporo-pollen assemblage and paleoclimate events in shelf area of the southern Yellow Sea since 15 ka B. P.

NASA Astrophysics Data System (ADS)

Meng, Guanglan; Han, Yousong; Wang, Shaoqing; Wang, Zhenyan

2004-03-01

Based on the authors’ 1986 to 1994 sporo-pollen assemblage analysis in the southern Yellow Sea area, data from 3 main cores were studied in combination with14C, palaeomagnetic and thermoluminescence data. The evolution of the paleoclimate environments in the southern Yellow Sea since 15ka B. P. was revealed that, in deglaciation of the last glacial period, the climate of late glaciation transformed into that of postglaciation, accompanied by a series of violent climate fluctuations. These evolution events happened in a global climate background and related to the geographic changes in eastern China. We distinguished three short-term cooling events and two warming events. Among them, the sporo-pollen assemblage of subzone A1 showed some cold climate features indicating that a cooling event occurred at about 15-14ka. B. P. in early deglaciation. This subzone corresponds to the Oldest Dryas. In subzone A3, many drought-enduring herbal pollens and some few pollens of cold-resistant Picea, Abies, etc. were found, which indicated that a cooling event, with cold and arid climate, occurred at about 12-11ka. B. P. in late deglaciation. This subzone corresponds to the Younger Dryas. The sporo-pollen assemblage of zone B showed warm and arid climate features in postglaciation. Although the assemblage of subzone B2 indicated a cold and arid climate environment, the development of flora in subzone B2 climate was less cold than that in A3. Subzone B2 indicated a cooling event which occurred at about 9ka B. P. in early olocene. Subzone A2, with some distinct differences from subzone A1 and A3, indicated a warming event which occurred at 14-13ka. B.P. and should correspond to a warming fluctuation. The sporo-pollen assemblage of zone C showed features of warn-moist flora and climate, and indicated a warming event which universally occurred along the coast of eastern China at 8-3 ka B. P. in middle Holocene, and its duration was longer than that of any climate events mentioned above. This period was climatic optimum and belonged to an altithermal period in postglaciation.

Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment

NASA Astrophysics Data System (ADS)

Zhu, R.; Lin, Y.-S.; Lipp, J. S.; Meador, T. B.; Hinrichs, K.-U.

2014-01-01

Amino sugars are quantitatively significant constituents of soil and marine sediment, but their sources and turnover in environmental samples remain poorly understood. The stable carbon isotopic composition of amino sugars can provide information on the lifestyles of their source organisms and can be monitored during incubations with labeled substrates to estimate the turnover rates of microbial populations. However, until now, such investigation has been carried out only with soil samples, partly because of the much lower abundance of amino sugars in marine environments. We therefore optimized a procedure for compound-specific isotopic analysis of amino sugars in marine sediment employing gas chromatography-isotope ratio mass spectrometry. The whole procedure consisted of hydrolysis, neutralization, enrichment, and derivatization of amino sugars. Except for the derivatization step, the protocol introduced negligible isotopic fractionation, and the minimum requirement of amino sugar for isotopic analysis was 20 ng, i.e. equivalent to ~ 8 ng of amino sugar carbon. Our results obtained from δ13C analysis of amino sugars in selected marine sediment samples showed that muramic acid had isotopic imprints from indigenous bacterial activities, whereas glucosamine and galactosamine were mainly derived from organic detritus. The analysis of stable carbon isotopic compositions of amino sugars opens a promising window for the investigation of microbial metabolisms in marine sediments and the deep marine biosphere.

Depostional systems, provenance, and sequence stratigraphy, Carter and [open quotes]Millerella[close quotes] sandstones of northeast Mississippi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleaves, A.W. II

1993-09-01

The subsurface [open quotes]Millerella[close quotes] and Carter sandstones (middle Chesterian) of the Black Warrior basin represent the highest units of the thick Muldon clastics deltaic facies tract. Lowstand marine conditions during Carter deposition allowed for southeastwardly progradation of five distinct deltaic lobe complexes onto the stable northern shelf of the basin. With each of these lobes, both an [open quotes]A[close quotes] (upper) and a [open quotes]B[close quotes] (lower) reservoir unit can be identified. The [open quotes]B[close quotes] sandstone produces from delta-front sheet sands, channel-mouth bars, and possible bar fingers of river-dominated deltas. The more prolific [open quotes]A[close quotes] subdivision containsmore » reservoirs in upper delta-plain point bars, crevasse splays, and distributary channel fills. The most easterly of the lobes, preserved in the Bean's Ferry field of Itawamba County, comprises an amalgamated valley-fill facies that removed a maximum of 250 ft (76 m) of lower Bangor platform carbonates. In contrast, the [open quotes]Millerella[close quotes] sandstone is a series of unconnected pods that formed as marine-reworked sand bodies during a eustatic rise in sea level. The average detrital sand grain composition for four cores taken in Monroe County is 94.7% monocrystalline quartz, 2.9% polycrystalline quartz, 1.6% albite feldspar, 0.1% low-rank metamorphic rock fragments, 0.5 chert, and 0.2% muscovite. These data indicate that neither the Ozark uplift nor the Ouachita orogen could have acted as the principal source area for the Carter and [open quotes]Millerella[close quotes] sandstones. More likely, the sedimentary-igneous terrains along the northern margin of the Illinois basin served this function. A major eustatic lowstand brought this mineralogically mature sediment across the Illinois basin through incised valleys to the northern self of the Black Warrior basin.« less

Comparisons between the characteristics of ichthyofaunas in nearshore waters of five estuaries with varying degrees of connectivity with the ocean

NASA Astrophysics Data System (ADS)

Hoeksema, S. D.; Chuwen, B. M.; Potter, I. C.

2009-10-01

The characteristics of the fish faunas in nearshore, shallow (<1.2 m) waters of the basins of estuaries along the same coastline, but which were open to the ocean for varying periods, have been determined and compared. The fish faunas of the permanently-open Oyster Harbour, the seasonally-open Broke, Irwin and Wilson inlets and the normally-closed Wellstead Estuary on the south coast of Western Australia were sampled by seine net seasonally for 2 years. Irrespective of the frequency and duration that the estuary mouth was open, the ichthyofauna of each estuary was numerically dominated by three atherinid species and three gobiid species (92.9-99.7%), each of which completes its life cycle within these estuaries. The ichthyofaunal compositions of each estuary differed significantly, however, from that of each other estuary. These differences were largely attributable to the relative abundances of the above six species varying between estuaries, which, in turn, reflected differences in such factors as estuary mouth status, macrophyte cover and salinity. For example, Favonigobius lateralis and Leptatherina presbyteroides, which are also represented by marine populations, were most abundant in the permanently-open estuary (Oyster Harbour), which, in terms of substrate and salinity, most closely resembled the nearshore marine environment. In contrast, Leptatherina wallacei made its greatest contribution in the only estuary to exhibit a protracted period of greatly reduced salinities, which is consistent with its distribution in permanently-open estuaries on the lower west coast of Australia, while Atherinosoma elongata and Pseudogobius olorum were particularly numerous in estuaries containing dense stands of the seagrass Ruppia megacarpa. Marine species made the greatest contribution to species richness in the permanently-open estuary and least in the normally-closed estuary. Species richness was greatest in summer and least in winter in each estuary, but differed markedly between years only in Wilson Inlet. Density of fishes was greatest in the most eutrophic estuary (Wellstead Estuary) and least in the most oligotrophic estuary (Broke Inlet) and only underwent marked seasonal variations in Wilson Inlet and Wellstead Estuary, in which densities fell to their minima in winter. Ichthyofaunal composition varied between years in the Broke and Wilson inlets and Wellstead Estuary, in which there was little or no connection with the ocean in one of those years. Species composition underwent progressive seasonal changes throughout the year in Wellstead Estuary, due to the abundance of certain species peaking at different times of the year.

Tectonic implications of facies patterns, Lower Permian Dry Mountain trough, east-central Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallegos, D.M.; Snyder, W.S.; Spinosa, C.

1991-02-01

Paleozoic tectonism is indicated by a study of a west-east facies analysis transect across the northern portion of the Lower Permian Dry Mountain trough (DMT). In an attempt to characterize the Early Permian basin-filling sequences, three broadly recognizable facies packages have been identified across the DMT: the western margin facies and the central basin facies of the DMT and an eastern shelf facies. In the western margin facies of the basin, pulses of tectonic activity are recorded at McCloud Spring in the Sulphur Springs Range. Here, shallow open-marine carbonate overlies eroded Vinini Formation and, in turn, is unconformably overlain bymore » basinal marine carbonate. An unconformity also marks the contact with the overriding prograding coarse clastic facies. These abrupt transitions suggest the sediments were deposited in a tectonically active area where they preservation of Waltherian sequences is unlikely to occur. Similarly abrupt transitions are evident in the western part of the central basin facies. At Portuguese Springs n the Diamond Range, a thin basal marine conglomerate delineates Lower Permian sedimentation over the Pennsylvanian Ely Formation. Coarsening-upward basinal carbonate strata of pelagic, hemipelagic, and turbidite components overlie the basal conglomerate. this progression of sediments is unconformably overlain by a subaerial sequence of coarse clastic deposits. Within the eastern part of the central basin facies in the Maverick Spring Range, the Lower Permian sediments are open-marine siltstone, wackestone, packstone, and grainstone. The sediments are assigned to a gradually sloping ramp, indicating the effects of tectonism on this margin of the basin were subdued.« less

A strategy for detecting derelict fishing gear at sea.

PubMed

McElwee, Kris; Donohue, Mary J; Courtney, Catherine A; Morishige, Carey; Rivera-Vicente, Ariel

2012-01-01

Derelict fishing gear (DFG) is a highly persistent form of marine pollution known to cause environmental and economic damage. At-sea detection of DFG would support pelagic removal of this gear to prevent and minimize impacts on marine environments and species. In 2008, experts in marine debris, oceanography, remote sensing, and marine policy outlined a strategy to develop the capability to detect and ultimately remove DFG from the open ocean. The strategy includes three interrelated components: understanding the characteristics of the targeted DFG, indirectly detecting DFG by modeling likely locations, and directly detecting pelagic DFG using remote sensing. Together, these components aim to refine the search area, increase the likelihood of detection, and decrease mitigation response time, thereby providing guidance for removal operations. Here, we present this at-sea detection strategy, relate it to relevant extant research and technology, and identify gaps that currently prevent successful at-sea detection and removal of DFG. Copyright © 2011 Elsevier Ltd. All rights reserved.

Floating marine litter as a raft for drifting voyages for Planes minutus (Crustacea: Decapoda: Grapsidae) and Liocarcinus navigator (Crustacea: Decapoda: Polybiidae).

PubMed

Tutman, P; Kapiris, K; Kirinčić, M; Pallaoro, A

2017-07-15

The Columbus crab Planes minutus and Arch-fronted swimming crab Liocarcinus navigator, within their distribution ranges in the Mediterranean, were found rafted on plastic macro-litter floating on the open south Adriatic. While P. minutus was recorded from inanimate flotsam outside of the Mediterranean, L. navigator is herein reported for the first time on floating marine litter. The role of floating litter as habitat or as a dispersal agent for marine invertebrates has received quite attention however, records of decapod crabs drifting on litter has been relatively sparse. Our results suggests that vast quantities of floating debris, comprised primarily of non-biodegradable plastic polymers, probably will augment natural floating substrates in the marine environment, potentially facilitating the spread of invasive species. The dispersion of rafting crabs through floating debris should be investigated given the high potential ecological risk of invasion by exotic species due to the increase in waste production (ecological risk assessment). Copyright © 2017 Elsevier Ltd. All rights reserved.

Marine Terrace Deposits along the Mediterranean Coast on the Southeastern Turkey and Their Implications for Tectonic Uplift and Sea Level Change

NASA Astrophysics Data System (ADS)

Tari, U.; Tüysüz, O.; Blackwell, B. A. B.; Genç, Ş. C.; Florentin, J. A.; Mahmud, Z.; Li, G. L.; Blickstein, J. I. B.; Skinner, A. R.

2016-12-01

Tectonic movements among the African, Arabian and Anatolian Plates have deformed the eastern Mediterranean. These movements caused transtensional opening of the NE-trending Antakya Graben since the late Pliocene. Tectonic uplift coupled with Quaternary sealevel fluctuations has produced several stacked marine terraces along the Mediterranean coasts on the graben. Here, marine terrace deposits that sit on both flanks of the graben at elevations between 3 and 175 m were dated using electron spin resonance (ESR) method in order to calculate uplift rates. The ESR ages range from 12 ka in late MIS 2 to 457 ka in MIS 9-11, but most of the terraces contain molluscs reworked from several earlier deposits due to successive tectonic movements and sealevel fluctuations. By dating in situ fossils, along the basal contacts of the marine terraces, uplift rates were calculated on both sides of the Antakya Graben. Results indicate that these deposits were mainly uplifted by local active faults rather than regional movements.

Use of biosensors for the detection of marine toxins

PubMed Central

McPartlin, Daniel A.; Lochhead, Michael J.; Connell, Laurie B.; Doucette, Gregory J.

2016-01-01

Increasing occurrences of harmful algal blooms (HABs) in the ocean are a major concern for countries around the globe, and with strong links between HABs and climate change and eutrophication, the occurrences are only set to increase. Of particular concern with regard to HABs is the presence of toxin-producing algae. Six major marine biotoxin groups are associated with HABs. Ingestion of such toxins via contaminated shellfish, fish, or other potential vectors, can lead to intoxication syndromes with moderate to severe symptoms, including death in extreme cases. There are also major economic implications associated with the diverse effects of marine biotoxins and HABs. Thus, effective monitoring programmes are required to manage and mitigate their detrimental global effect. However, currently legislated detection methods are labour-intensive, expensive and relatively slow. The growing field of biosensor diagnostic devices is an exciting area that has the potential to produce robust, easy-to-use, cost-effective, rapid and accurate detection methods for marine biotoxins and HABs. This review discusses recently developed biosensor assays that target marine biotoxins and their microbial producers, both in harvested fish/shellfish samples and in the open ocean. The effective deployment of such biosensor platforms could address the pressing need for improved monitoring of HABs and marine biotoxins, and could help to reduce their global economic impact. PMID:27365035

Shallow marine response to global climate change during the Paleocene-Eocene Thermal Maximum, Salisbury Embayment, USA

USGS Publications Warehouse

Self-Trail, Jean; Robinson, Marci M.; Bralower, Timothy J.; Sessa, Jocelyn A.; Hajek, Elizabeth A.; Kump, Lee R.; Trampush, Sheila M.; Willard, Debra A.; Edwards, Lucy E.; Powars, David S.; Wandless, Gregory A.

2017-01-01

The Paleocene-Eocene Thermal Maximum (PETM) was an interval of extreme warmth that caused disruption of marine and terrestrial ecosystems on a global scale. Here we examine the sediments, flora, and fauna from an expanded section at Mattawoman Creek-Billingsley Road (MCBR) in Maryland and explore the impact of warming at a nearshore shallow marine (30–100 m water depth) site in the Salisbury Embayment. Observations indicate that at the onset of the PETM, the site abruptly shifted from an open marine to prodelta setting with increased terrestrial and fresh water input. Changes in microfossil biota suggest stratification of the water column and low-oxygen bottom water conditions in the earliest Eocene. Formation of authigenic carbonate through microbial diagenesis produced an unusually large bulk carbon isotope shift, while the magnitude of the corresponding signal from benthic foraminifera is similar to that at other marine sites. This proves that the landward increase in the magnitude of the carbon isotope excursion measured in bulk sediment is not due to a near instantaneous release of 12C-enriched CO2. We conclude that the MCBR site records nearshore marine response to global climate change that can be used as an analog for modern coastal response to global warming.

Shallow marine response to global climate change during the Paleocene-Eocene Thermal Maximum, Salisbury Embayment, USA

NASA Astrophysics Data System (ADS)

Self-Trail, Jean M.; Robinson, Marci M.; Bralower, Timothy J.; Sessa, Jocelyn A.; Hajek, Elizabeth A.; Kump, Lee R.; Trampush, Sheila M.; Willard, Debra A.; Edwards, Lucy E.; Powars, David S.; Wandless, Gregory A.

2017-07-01

The Paleocene-Eocene Thermal Maximum (PETM) was an interval of extreme warmth that caused disruption of marine and terrestrial ecosystems on a global scale. Here we examine the sediments, flora, and fauna from an expanded section at Mattawoman Creek-Billingsley Road (MCBR) in Maryland and explore the impact of warming at a nearshore shallow marine (30-100 m water depth) site in the Salisbury Embayment. Observations indicate that at the onset of the PETM, the site abruptly shifted from an open marine to prodelta setting with increased terrestrial and fresh water input. Changes in microfossil biota suggest stratification of the water column and low-oxygen bottom water conditions in the earliest Eocene. Formation of authigenic carbonate through microbial diagenesis produced an unusually large bulk carbon isotope shift, while the magnitude of the corresponding signal from benthic foraminifera is similar to that at other marine sites. This proves that the landward increase in the magnitude of the carbon isotope excursion measured in bulk sediment is not due to a near instantaneous release of 12C-enriched CO2. We conclude that the MCBR site records nearshore marine response to global climate change that can be used as an analog for modern coastal response to global warming.

SIMOcean: Maritime Open Data and Services Platform for Portuguese Institutions

NASA Astrophysics Data System (ADS)

Almeida, Nuno; Grosso, Nuno; Catarino, Nuno; Gutierrez, Antonio; Lamas, Luísa; Alves, Margarida; Almeida, Sara; Deus, Ricardo; Oliveira, Paulo

2016-04-01

Portugal is the country with the largest EEZ in the EU and the 10th largest EEZ in the world, at 3,877,408 km2, rendering the existence of an integrated management of Portuguese marine system crucial to monitor a wide range of interdependent domains. A system like this assimilates data and information from different thematic areas, ranging from ocean and atmosphere state variables to higher level datasets describing human activities and related environmental, social and economic impacts. Currently, these datasets are collected by a wide number of public and private institutions with very diverse purposes (e.g., monitoring, research, recreation, vigilance) leading to dataset duplication, inexistence of common data and metadata standards across organizations, and the propagation of closed information systems with different implementation solutions. This lack of coordination and visibility hinders the marine management, monitoring and vigilance capabilities, not only by making it more difficult to access, or even be aware of, the existence of certain datasets, but also by minimizing the ability to create added value products or services through dataset integration from different sources. Adopting Open Data approach will bring significant benefits by reducing the cost of information exchange and data integration, promoting the extensive use of this data. SIMOcean (System for Integrated Monitoring of the Ocean), co-funded by the EEA Grants Programme, is integrated in the initiative of the Portuguese Government to develop a set of coordinated systems providing access to national marine data. These systems aim to improve the Portuguese marine management, monitoring and vigilance capabilities, aggregating different data, including specific human activities datasets (vessel traffic, fishing records, oil spills), and environment variables (waves, currents, wind). Those datasets, currently scattered among different departments of the Portuguese Meteorological (IPMA) and the Navy's Hydrographic (IH) Institutes, will be brought together in the SIMOcean Open Data system. The SIMOcean system will also exploit this data in the following three flagship value added services: 1) Characterisation of Fishing Areas; 2) Wave Alerts for Sea Ports; and 3) Support to Search and Rescue Missions. These services will be driven by end users such as Civil Protection Authorities, Port Authorities and Fishing Associations, where these new products will lead to a significant positive impact in their operations. SIMOcean will be based on open source web based GIS interoperable solutions, compliant with OGC and INSPIRE directive standards to support the evolution of a set of open interfaces and protocols in the development of a common European spatial data infrastructure. The Catalogue solution (based on ckan) will consider the Portuguese Metadata Profile for the Sea developed by SNIM@R project, the guidelines provided by the directive 2013/37/EU and the Goldbook provided by the European Data portal. The system will be based on SenSyF approach of a scalable Cloud Computing system, providing authorised entities a single access point system for data catalogue, visualisation, processing and value added service deployment. It will be used by the two of the main Portuguese sea data providers with operational responsibilities in marine management, monitoring and vigilance.

FLYING CADET MESS HALL, FOR 250 MEN, PLANS & DETAILS. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FLYING CADET MESS HALL, FOR 250 MEN, PLANS & DETAILS. Sheet No. 1 of 6, dated March 30, 1942. U.S. Engineer Office, San Francisco, California - Hamilton Field, Airmen's Open Mess, First cul-de-sac on F Street, Novato, Marin County, CA

FLYING CADET MESS HALL, FOR 250 MEN, ELEVATIONS, SECTION, & ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FLYING CADET MESS HALL, FOR 250 MEN, ELEVATIONS, SECTION, & DETAILS. Sheet No. 2 of 6, dated March 30, 1942. U.S. Engineer Office, San Francisco, California - Hamilton Field, Airmen's Open Mess, First cul-de-sac on F Street, Novato, Marin County, CA

77 FR 51039 - Merchant Mariner Medical Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-23

... the physical qualifications of operators of commercial vessels; medical examiner education; and..., medical standards and guidelines for physical qualifications of operators of commercial vessels, medical examiner education, and medical research. The meeting will be open to the public. DATES: MMMAC will meet on...

77 FR 31327 - Pacific Fishery Management Council; Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-25

... Fishery Management Council; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National... Pacific Fishery Management Council's (Pacific Council) Habitat Committee (HC) will hold a meeting, which is open to the public, to discuss habitat issues related to Council-managed fisheries. DATES: The...

Large-Scale Trade in Legally Protected Marine Mollusc Shells from Java and Bali, Indonesia

PubMed Central

Nijman, Vincent; Spaan, Denise; Nekaris, K. Anne-Isola

2015-01-01

Background Tropical marine molluscs are traded globally. Larger species with slow life histories are under threat from over-exploitation. We report on the trade in protected marine mollusc shells in and from Java and Bali, Indonesia. Since 1987 twelve species of marine molluscs are protected under Indonesian law to shield them from overexploitation. Despite this protection they are traded openly in large volumes. Methodology/Principal Findings We collected data on species composition, origins, volumes and prices at two large open markets (2013), collected data from wholesale traders (2013), and compiled seizure data by the Indonesian authorities (2008–2013). All twelve protected species were observed in trade. Smaller species were traded for 32,000 shells valued at USD500,000), chambered nautilus (Nautilus pompilius) (>3,000 shells, USD60,000) and giant clams (Tridacna spp.) (>2,000 shells, USD45,000) were traded in largest volumes. Two-thirds of this trade was destined for international markets, including in the USA and Asia-Pacific region. Conclusions/Significance We demonstrated that the trade in protected marine mollusc shells in Indonesia is not controlled nor monitored, that it involves large volumes, and that networks of shell collectors, traders, middlemen and exporters span the globe. This impedes protection of these species on the ground and calls into question the effectiveness of protected species management in Indonesia; solutions are unlikely to be found only in Indonesia and must involve the cooperation of importing countries. PMID:26717021

Holocene environmental changes recorded in Dicksonfjorden and Woodfjorden, Svalbard: impacts of global climate changes in a glacial-marine system

NASA Astrophysics Data System (ADS)

Joo, Y. J.; Nam, S. I.; Son, Y. J.; Forwick, M.

2017-12-01

Fjords in the Svalbard archipelago are characterized by an extreme environmental gradient between 1) the glacial system affected by tidewater glaciers and seasonal sea ice inside the fjords and 2) the warm Atlantic Water intrusion by the West Spitsbergen Current from open ocean. As sediment is largely supplied from the terrestrial source area exposed along the steep slopes of the fjords, the changes in the surface processes affected by glaciers are likely preserved in the sediments in the inner fjords. On the other hand, variations in the influence of the warm Atlantic Water in the marine realm (e.g. marine productivity) can be archived in the sediment deposited in the vicinity of the entrance to the fjords. Since the last deglaciation of the Svalbard-Barents ice sheet ( 13000 yrs BP), the Svalbard fjords have faced dramatic climate changes including the early Holocene Climate Optimum (HCO) and subsequent cooling that eventually led to the current cold and dry climate. We investigate the Holocene environmental changes in both terrestrial and marine realms based on stable isotopic and inorganic geochemical analyses of sediments deposited in Dicksonfjorden and Woodfjorden in the western and northern Spitsbergen, respectively. The two fjords are expected to provide intriguing information regarding how terrestrial and marine realms of the Arctic fjords system responded to regional and global climate changes. Being a branch of the larger Isfjorden, Dicksonfjorden penetrates deeply to the land, whereas Woodfjorden is rather directly connected to the open ocean. Accordingly, the results suggest that the Dicksonfjorden sediment records mainly terrestrial signals with marked fluctuations in sediment composition that coincide with major climate changes (e.g. HCO). On the contrary, the two Woodfjorden cores collected from different parts of the fjord exhibit contrasting results, likely illustrating differing response of terrestrial and marine realms to the climate changes in terms of behavior of tidewater glaciers and inflow of the warm West Spitsbergen Current and their possible interactions. This study aims to disentangle the interaction between the fjords and the global climate changes and provide a holistic view to the Arctic fjords system with strong environmental gradients.

A postglacial coleopterous assemblage from Lockport Gulf, New York

NASA Astrophysics Data System (ADS)

Miller, Randy F.; Morgan, Alan V.

1982-03-01

The Lockport Gulf site near Lockport, New York, is a 1.9-m sequence of organic-rich marls having a basal date of approximately 10,920 yr B.P. Six bulk samples with a combined weight of 48 kg produced over 780 individual fossil insects representing five orders, as well as molluscs and abundant plant macrofossils. Coleoptera were represented by 24 families. Several major beetle groups (Carabidae, ground beetles; Hydrophilidae, water scavenger beetles; Elmidae, riffle beetles; Staphylinidae, rove beetles; and Scolytidae, bark beetles) indicate a riffle-and-pool stream, surrounded by marsh, with open riparian habitats and nearby trees. Two zones were recognized based on the Coleoptera assemblages. The Zone 1 fauna (ca. 10,920-9800 yr B.P.) was dominated by boreal forest taxa with abundant bark beetles indicating the presence of spruce trees. In Zone 2 (ca. 9700-9100 yr B.P.) the combination of species with a restricted modern distribution in the Great Lakes-St. Lawrence Forest region and pine and deciduous tree inhabitants suggests a change in vegetation by 9700 yr B.P. Thermal estimates from a faunal analysis indicate that the climatic conditions were stable across the spruce-pine transition, with the mean July temperature in the range of 16° to 18°C.

Climatic forcing of carbon-oxygen isotopic covariance in temperate-region marl lakes

NASA Technical Reports Server (NTRS)

Drummond, C. N.; Patterson, W. P.; Walker, J. C.

1995-01-01

Carbon and oxygen stable isotopic compositions of lacustrine carbonate from a southeastern Michigan marl lake display linear covariance over a range of 4.0% Peedee belemnite (PDB) in oxygen and 3.9% (PDB) in carbon. Mechanisms of delta 13 C-delta 18 O coupling conventionally attributed to lake closure in arid-region basins are inapplicable to hydrologically open lake systems. Thus, an alternative explanation of isotopic covariance in temperate region dimictic marl lakes is required. We propose that isotopic covariance is a direct record of change in regional climate. In short-residence-time temperate-region lake basins, summer meteoric precipitation is enriched in 18O relative to winter values, and summer organic productivity enriches epilimnic dissolved inorganic carbon in 13C. Thus, climate change toward longer summers and/or shorter winters could result in greater proportions of warm-month meteoric precipitation, longer durations of warm-month productivity, and net long-term enrichment in carbonate 18O and 13C. Isotopic covariance observed in the Michigan marl lake cores is interpreted to reflect postglacial warming from 10 to 3 ka followed by cooler mean annual temperature, a shift toward greater proportions of seasonal summer precipitation, a shortening of the winter season, or some combination of these three factors.

The Adriatic Sea: A Long-Standing Laboratory for Sea Level Studies

NASA Astrophysics Data System (ADS)

Vilibić, Ivica; Šepić, Jadranka; Pasarić, Mira; Orlić, Mirko

2017-10-01

The paper provides a comprehensive review of all aspects of Adriatic Sea level research covered by the literature. It discusses changes occurring over millennial timescales and documented by a variety of natural and man-made proxies and post-glacial rebound models; mean sea level changes occurring over centennial to annual timescales and measured by modern instruments; and daily and higher-frequency changes (with periods ranging from minutes to a day) that are contributing to sea level extremes and are relevant for present-day flooding of coastal areas. Special tribute is paid to the historic sea level studies that shaped modern sea level research in the Adriatic, followed by a discussion of existing in situ and remote sensing observing systems operating in the Adriatic area, operational forecasting systems for Adriatic storm surges, as well as warning systems for tsunamis and meteotsunamis. Projections and predictions of sea level and related hazards are also included in the review. Based on this review, open issues and research gaps in the Adriatic Sea level studies are identified, as well as the additional research efforts needed to fill the gaps. The Adriatic Sea, thus, remains a laboratory for coastal sea level studies for semi-enclosed, coastal and marginal seas in the world ocean.

A statistical analysis of North East Atlantic (submicron) aerosol size distributions

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Monahan, C.; Greaney, R.; Beddows, D. C. S.; Harrison, R. M.; Ceburnis, D.; O'Dowd, C. D.

2011-08-01

The Global Atmospheric Watch research station at Mace Head (Ireland) offers the possibility to sample some of the cleanest air masses being imported into Europe as well as some of the most polluted being exported out of Europe. We present a statistical Cluster~analysis of the physical characteristics of aerosol size distributions in air ranging from the cleanest to the most polluted for the year 2008. Data coverage achieved was 75 % throughout the year. By applying the Hartigan-Wong k-Means method, 12 Clusters were identified as systematically occurring and these 12 Clusters could be further combined into 4 categories with similar characteristics, namely: coastal nucleation category (occurring 21.3 % of the time), open ocean nucleation category (occurring 32.6 % of the time), background clean marine category (occurring 26.1 % of the time) and anthropogenic category (occurring 20 % of the time) aerosol size distributions. The coastal nucleation category is characterised by a clear and dominant nucleation mode at sizes less that 10 nm while the open ocean nucleation category is characterised by a dominant Aitken mode between 15 nm and 50 nm. The background clean marine characteristic is a clear bimodality in the size distribution, although it should be noted that either the Aitken mode or the Accumulation mode may dominate the number concentration. By contrast, the continentally-influenced size distributions are generally more mono-modal, albeit with traces of bi-modality. The open ocean category occurs more often during May, June and July, corresponding with the N. E. Atlantic high biological period. Combined with the relatively high percentage frequency of occurrence (32.6 %), this suggests that the marine biota is an important source of new aerosol particles in N. E. Atlantic Air.

Open Ocean Assessments for Management in the GEF Transboundary Waters Assessment Project (TWAP)

NASA Astrophysics Data System (ADS)

Fischer, A. S.; Alverson, K. D.

2010-12-01

A methodology for a thematic and scientifically-credible assessment of Open Ocean waters as a part of the Global Environment Facility (GEF) Transboundary Waters Assessment Project (TWAP) has been developed in the last 18 months by the Intergovernmental Oceanographic Commission of UNESCO, and is presented for feedback and comment. While developed to help the GEF International Waters focal area target investment to manage looming environmental threats in interlinked freshwater and marine systems (a very focused decision support system), the assessment methodology could contribute to other assessment and management efforts in the UN system and elsewhere. Building on a conceptual framework that describes the relationships between human systems and open ocean natural systems, and on mapping of the human impact on the marine environment, the assessment will evaluate and make projections on a thematic basis, identifying key metrics, indices, and indicators. These themes will include the threats on key ecosystem services of climate change through sea level rise, changed stratification, warming, and ocean acidification; vulnerabilities of ecosystems, habitats, and living marine resources; the impact and sustainability of fisheries; and pollution. Global-level governance arrangements will also be evaluated, with an eye to identifying scope for improved global-level management. The assessment will build on sustained ocean observing systems, model projections, and an assessment of scientific literature, as well as tools for combining knowledge to support identification of priority concerns and in developing scenarios for management. It will include an assessment of key research and observing needs as one way to deal with the scientific uncertainty inherent in such an exercise, and to better link policy and science agendas.

Semantics in NETMAR (open service NETwork for MARine environmental data)

NASA Astrophysics Data System (ADS)

Leadbetter, Adam; Lowry, Roy; Clements, Oliver

2010-05-01

Over recent years, there has been a proliferation of environmental data portals utilising a wide range of systems and services, many of which cannot interoperate. The European Union Framework 7 project NETMAR (that commenced February 2010) aims to provide a toolkit for building such portals in a coherent manner through the use of chained Open Geospatial Consortium Web Services (WxS), OPeNDAP file access and W3C standards controlled by a Business Process Execution Language workflow. As such, the end product will be configurable by user communities interested in developing a portal for marine environmental data, and will offer search, download and integration tools for a range of satellite, model and observed data from open ocean and coastal areas. Further processing of these data will also be available in order to provide statistics and derived products suitable for decision making in the chosen environmental domain. In order to make the resulting portals truly interoperable, the NETMAR programme requires a detailed definition of the semantics of the services being called and the data which are being requested. A key goal of the NETMAR programme is, therefore, to develop a multi-domain and multilingual ontology of marine data and services. This will allow searches across both human languages and across scientific domains. The approach taken will be to analyse existing semantic resources and provide mappings between them, gluing together the definitions, semantics and workflows of the WxS services. The mappings between terms aim to be more general than the standard "narrower than", "broader than" type seen in the thesauri or simple ontologies implemented by previous programmes. Tools for the development and population of ontologoies will also be provided by NETMAR as there will be instances in which existing resources cannot sufficiently describe newly encountered data or services.

Seasonal and long-term changes in elemental concentrations and ratios of marine particulate organic matter

NASA Astrophysics Data System (ADS)

Talarmin, Agathe; Lomas, Michael W.; Bozec, Yann; Savoye, Nicolas; Frigstad, Helene; Karl, David M.; Martiny, Adam C.

2016-11-01

What is the temporal variability of the elemental stoichiometry of marine microbial communities across ocean regions? To answer this question, we present an analysis of environmental conditions, particulate organic carbon, nitrogen, and phosphorus concentrations and their ratios across 20 time series (3-25 years duration) representing estuarine, coastal, and open ocean environments. The majority of stations showed significant seasonal oscillations in particulate organic elemental concentrations and ratios. However, shorter-term changes contributed most to overall variance in particulate organic matter concentrations and ratios. We found a correlation between the seasonal oscillations of environmental conditions and elemental ratios at many coastal but not open ocean and estuarine stations. C:N peaked near the seasonal temperature minimum and nutrient maximum, but some stations showed other seasonal links. C:N ratios declined with time over the respective observation periods at all open ocean and estuarine stations as well as at five coastal station but increased at the nine other coastal stations. C:P (but not N:P) declined slightly at Bermuda Atlantic Time-series Study but showed large significant increases at Hawaii Ocean Time-series and Arendal stations. The relationships between long-term changes in environmental conditions and particulate organic matter concentrations or ratios were ambiguous, but interactions between changes in temperature and nutrient availability were important. Overall, our analysis demonstrates significant changes in elemental ratios at long-term and seasonal time scales across regions, but the underlying mechanisms are currently unclear. Thus, we need to better understand the detailed mechanisms driving the elemental composition of marine microbial ecosystems in order to predict how oceans will respond to environmental changes.

Evaluating Effects of Stressors from Marine and Hydrokinetic Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Copping, Andrea E.; Blake, Kara M.; Hanna, Luke A.

2012-09-30

Potential environmental effects of marine and hydrokinetic (MHK) energy development are not well understood, yet regulatory agencies are required to make decisions in spite of substantial uncertainty about environmental impacts and their long-term consequences. An understanding of risks associated with interactions between MHK installations and aquatic receptors, including animals, habitats, and ecosystems, can help define key uncertainties and focus regulatory actions and scientific studies on interactions of most concern. During FY 2012, Pacific Northwest National Laboratory (PNNL) continued to follow project developments on the two marine and hydrokinetic projects reviewed for Environmental Risk Evaluation System (ERES) screening analysis in FYmore » 2011: a tidal project in the Gulf of Maine using Ocean Renewable Power Company TidGenTM turbines and a wave project planned for the coast of Oregon using Aquamarine Oyster surge devices. The ERES project in FY 2012 also examined two stressor–receptor interactions previously identified through the screening process as being of high importance: 1) the toxicity effects of antifouling coatings on MHK devices on aquatic resources and 2) the risk of a physical strike encounter between an adult killer whale and an OpenHydro turbine blade. The screening-level assessment of antifouling paints and coatings was conducted for two case studies: the Snohomish County Public Utility District No. 1 (SnoPUD) tidal turbine energy project in Admiralty Inlet, Puget Sound, Washington, and the Ocean Power Technologies (OPT) wave buoy project in Reedsport, Oregon. Results suggest minimal risk to aquatic biota from antifouling coatings used on MHK devices deployed in large estuaries or open ocean environments. For the strike assessment of a Southern Resident Killer Whale (SRKW) encountering an OpenHydro tidal turbine blade, PNNL teamed with colleagues from Sandia National Laboratories (SNL) to carry out an analysis of the mechanics and biological consequences of different blade strike scenarios. Results of these analyses found the following: 1) a SRKW is not likely to experience significant tissue injury from impact by an OpenHydro turbine blade; and 2) if whale skin behaves similarly to the materials considered as surrogates for the upper dermal layers of whale skin, it would not be torn by an OpenHydro blade strike. The PNNL/SNL analyses could not provide insight into the potential for more subtle changes to SRKWs from an encounter with a turbine, such as changes in behavior, or inform turbine interactions for other whales or other turbines. These analyses were limited by the available time frame in which results were needed and focused on the mechanical response of whale tissues and bone to blade strike. PNNL proposes that analyses of additional turbine designs and interactions with other marine mammals that differ in size, body conformation, and mass be performed.« less

Flotation Analysis for Boat Docks on U.S. Army Corps of Engineers Projects. Recreation Management Support Program

DTIC Science & Technology

2009-06-01

USACE 2008c)) on June 3, 1992 that “effectively precludes the future use of expanded polystyrene unless it is encased in an approved protective coating...punctured. Closed cell (extruded) expanded polystyrene of good quality and manufac- tured for marine use will be required. Lesser quality foam bead flota...Forest Service (USFS) (USFS 2008) – “Open cell Expanded Polystyrene Foam (EPS) has an open structure that easily lets water into its interior. It

Cumulative and Synergistic Effects of Physical, Biological and Acoustic Signals on Marine Mammal Habitat Use

DTIC Science & Technology

2011-09-30

M5 mooring demonstrated at least five different soundscapes associated with sea ice coverage (Fig. 2). The ice pack was present at M5 from Day 5...Feb – Mar 16) (Miksis-Olds et al. 2011, submitted). This episode was detected acoustically, including the acoustic soundscape of open water on...ice breakup/melting occurred. The ice season ended on May 17 (Day 137), when open water soundscapes are present. 4 Figure 2. A

The effects of time on the capacity of pipe piles in dense marine sand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chow, F.C.; Jardine, R.J.; Brucy, F.

Investigations into pile behavior in dense marine sand have been performed by IFP and IC at Dunkirk, North France. In the most recent series of tests, strain-gauged, open-ended pipe piles, driven and statically load tested in 1989, were retested in 1994. Surprisingly large increases in shaft capacity were measured. The possible causes are evaluated in relation to previous case histories, laboratory soil tests, pile corrosion and new effective stress analyses developed using smaller, more intensively instrumented piles. The shaft capacities predicted by existing design methods are also assessed. 51 refs., 12 figs., 4 tabs.

Multiple spatial modes based QKD over marine free-space optical channels in the presence of atmospheric turbulence.

PubMed

Sun, Xiaole; Djordjevic, Ivan B; Neifeld, Mark A

2016-11-28

We investigate a multiple spatial modes based quantum key distribution (QKD) scheme that employs multiple independent parallel beams through a marine free-space optical channel over open ocean. This approach provides the potential to increase secret key rate (SKR) linearly with the number of channels. To improve the SKR performance, we describe a back-propagation mode (BPM) method to mitigate the atmospheric turbulence effects. Our simulation results indicate that the secret key rate can be improved significantly by employing the proposed BPM-based multi-channel QKD scheme.

Applying Sensor Web Technology to Marine Sensor Data

NASA Astrophysics Data System (ADS)

Jirka, Simon; del Rio, Joaquin; Mihai Toma, Daniel; Nüst, Daniel; Stasch, Christoph; Delory, Eric

2015-04-01

In this contribution we present two activities illustrating how Sensor Web technology helps to enable a flexible and interoperable sharing of marine observation data based on standards. An important foundation is the Sensor Web Architecture developed by the European FP7 project NeXOS (Next generation Low-Cost Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management). This architecture relies on the Open Geospatial Consortium's (OGC) Sensor Web Enablement (SWE) framework. It is an exemplary solution for facilitating the interoperable exchange of marine observation data within and between (research) organisations. The architecture addresses a series of functional and non-functional requirements which are fulfilled through different types of OGC SWE components. The diverse functionalities offered by the NeXOS Sensor Web architecture are shown in the following overview: - Pull-based observation data download: This is achieved through the OGC Sensor Observation Service (SOS) 2.0 interface standard. - Push-based delivery of observation data to allow users the subscription to new measurements that are relevant for them: For this purpose there are currently several specification activities under evaluation (e.g. OGC Sensor Event Service, OGC Publish/Subscribe Standards Working Group). - (Web-based) visualisation of marine observation data: Implemented through SOS client applications. - Configuration and controlling of sensor devices: This is ensured through the OGC Sensor Planning Service 2.0 interface. - Bridging between sensors/data loggers and Sensor Web components: For this purpose several components such as the "Smart Electronic Interface for Sensor Interoperability" (SEISI) concept are developed; this is complemented by a more lightweight SOS extension (e.g. based on the W3C Efficient XML Interchange (EXI) format). To further advance this architecture, there is on-going work to develop dedicated profiles of selected OGC SWE specifications that provide stricter guidance how these standards shall be applied to marine data (e.g. SensorML 2.0 profiles stating which metadata elements are mandatory building upon the ESONET Sensor Registry developments, etc.). Within the NeXOS project the presented architecture is implemented as a set of open source components. These implementations can be re-used by all interested scientists and data providers needing tools for publishing or consuming oceanographic sensor data. In further projects such as the European project FixO3 (Fixed-point Open Ocean Observatories), these software development activities are complemented with additional efforts to provide guidance how Sensor Web technology can be applied in an efficient manner. This way, not only software components are made available but also documentation and information resources that help to understand which types of Sensor Web deployments are best suited to fulfil different types of user requirements.

In situ associations between marine photosynthetic picoeukaryotes and potential parasites - a role for fungi?

PubMed

Lepère, Cécile; Ostrowski, Martin; Hartmann, Manuela; Zubkov, Mikhail V; Scanlan, David J

2016-08-01

Photosynthetic picoeukaryotes (PPEs) are important components of the marine picophytoplankton community playing a critical role in CO2 fixation but also as bacterivores, particularly in the oligotrophic gyres. Despite an increased interest in these organisms and an improved understanding of the genetic diversity of this group, we still know little of the environmental factors controlling the abundance of these organisms. Here, we investigated the quantitative importance of eukaryotic parasites in the free-living fraction as well as in associations with PPEs along a transect in the South Atlantic. Using tyramide signal amplification-fluorescence in situ hybridization (TSA-FISH), we provide quantitative evidence of the occurrence of free-living fungi in open ocean marine systems, while the Perkinsozoa and Syndiniales parasites were not abundant in these waters. Using flow cytometric cell sorting of different PPE populations followed by a dual-labelled TSA-FISH approach, we also demonstrate fungal associations, potentially parasitic, occurring with both pico-Prymnesiophyceae and pico-Chrysophyceae. These data highlight the necessity for further work investigating the specific role of marine fungi as parasites of phytoplankton to improve understanding of carbon flow in marine ecosystems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Marine and giant viruses as indicators of a marine microbial community in a riverine system.

PubMed

Dann, Lisa M; Rosales, Stephanie; McKerral, Jody; Paterson, James S; Smith, Renee J; Jeffries, Thomas C; Oliver, Rod L; Mitchell, James G

2016-12-01

Viral communities are important for ecosystem function as they are involved in critical biogeochemical cycles and controlling host abundance. This study investigates riverine viral communities around a small rural town that influences local water inputs. Myoviridae, Siphoviridae, Phycodnaviridae, Mimiviridae, Herpesviridae, and Podoviridae were the most abundant families. Viral species upstream and downstream of the town were similar, with Synechoccocus phage, salinus, Prochlorococcus phage, Mimivirus A, and Human herpes 6A virus most abundant, contributing to 4.9-38.2% of average abundance within the metagenomic profiles, with Synechococcus and Prochlorococcus present in metagenomes as the expected hosts for the phage. Overall, the majority of abundant viral species were or were most similar to those of marine origin. At over 60 km to the river mouth, the presence of marine communities provides some support for the Baas-Becking hypothesis "everything is everywhere, but, the environment selects." We conclude marine microbial species may occur more frequently in freshwater systems than previously assumed, and hence may play important roles in some freshwater ecosystems within tens to a hundred kilometers from the sea. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Marine fog: a review

USGS Publications Warehouse

Koračin, Darko; Dorman, Clive E.; Lewis, John M.; Hudson, James G.; Wilcox, Eric M.; Torregrosa, Alicia

2014-01-01

The objective of this review is to discuss physical processes over a wide range of spatial scales that govern the formation, evolution, and dissipation of marine fog. We consider marine fog as the collective combination of fog over the open sea along with coastal sea fog and coastal land fog. The review includes a history of sea fog research, field programs, forecasting methods, and detection of sea fog via satellite observations where similarity in radiative properties of fog top and the underlying sea induce further complexity. The main thrust of the study is to provide insight into causality of fog including its initiation, maintenance, and destruction. The interplay between the various physical processes behind the several stages of marine fog is among the most challenging aspects of the problem. An effort is made to identify this interplay between processes that include the microphysics of fog formation and maintenance, the influence of large-scale circulation and precipitation/clouds, radiation, turbulence (air-sea interaction), and advection. The environmental impact of marine fog is also addressed. The study concludes with an assessment of our current knowledge of the phenomenon, our principal areas of ignorance, and future lines of research that hold promise for advances in our understanding.

Environmental implications of plastic debris in marine settings—entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions

PubMed Central

Gregory, Murray R.

2009-01-01

Over the past five or six decades, contamination and pollution of the world’s enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials (generally known as ‘marine debris’) has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as ‘hangers-on and hitch-hikers’ as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats. PMID:19528053

Biological and ecological traits of marine species

PubMed Central

Claus, Simon; Dekeyzer, Stefanie; Vandepitte, Leen; Tuama, Éamonn Ó; Lear, Dan; Tyler-Walters, Harvey

2015-01-01

This paper reviews the utility and availability of biological and ecological traits for marine species so as to prioritise the development of a world database on marine species traits. In addition, the ‘status’ of species for conservation, that is, whether they are introduced or invasive, of fishery or aquaculture interest, harmful, or used as an ecological indicator, were reviewed because these attributes are of particular interest to society. Whereas traits are an enduring characteristic of a species and/or population, a species status may vary geographically and over time. Criteria for selecting traits were that they could be applied to most taxa, were easily available, and their inclusion would result in new research and/or management applications. Numerical traits were favoured over categorical. Habitat was excluded as it can be derived from a selection of these traits. Ten traits were prioritized for inclusion in the most comprehensive open access database on marine species (World Register of Marine Species), namely taxonomic classification, environment, geography, depth, substratum, mobility, skeleton, diet, body size and reproduction. These traits and statuses are being added to the database and new use cases may further subdivide and expand upon them. PMID:26312188

Environmental implications of plastic debris in marine settings--entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions.

PubMed

Gregory, Murray R

2009-07-27

Over the past five or six decades, contamination and pollution of the world's enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials (generally known as 'marine debris') has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as 'hangers-on and hitch-hikers' as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats.

Drake Passage opening history: a synthesis of existing and new data from diverse proxies

NASA Astrophysics Data System (ADS)

Barbeau, D. L.; Scotia Project Team

2011-12-01

The tectonic opening of the Drake Passage marine gateway between the Antarctic Peninsula and southern South America enabled development of the Antarctic circumpolar current, which has been variably ascribed to establishment and/or expansion of Cenozoic ice caps on Antarctica. Despite the importance of this gateway, interpretations of its opening history vary greatly, and are widely debated. Using data collected using a variety of geologic, geochemical, geophysical, and paleobiologic techniques, I summarize existing and new constraints on the tectonic history of Drake Passage, and evaluate temporal and kinematic models for its opening. In particular, new data from sediment provenance and thermochronology of Drake Passage margins integrated with independent paleoclimate, eustasy and paleobiology studies suggest that this gateway may have begun opening at least as early as the Paleocene -- 15 Myr prior to the oldest previous estimates.

Mitochondrial diversity patterns and the Magdalenian resettlement of Europe: new insights from the edge of the Franco-Cantabrian refuge.

PubMed

Pardiñas, Antonio F; Roca, Agustín; Garcia-Vazquez, Eva; Lopez, Belen

2012-11-26

Phylogeography of the mitochondrial lineages commonly found in Western Europe can be interpreted in the light of a postglacial resettlement of the continent. The center of this proposal lies in the Franco-Cantabrian glacial refuge, located in the northern Iberian Peninsula and Southwestern France. Recently, this interpretation has been confronted by the unexpected patterns of diversity found in some European haplogroups. To shed new lights on this issue, research on Iberian populations is crucial if events behind the actual genetics of the European continent are to be untangled. In this regard, the region of Asturias has not been extensively studied, despite its convoluted history with prolonged periods of isolation. As mitochondrial DNA is a kind of data that has been commonly used in human population genetics, we conducted a thorough regional study in which we collected buccal swabs from 429 individuals with confirmed Asturian ancestry. The joint analysis of these sequences with a large continent-wide database and previously published diversity patterns allowed us to discuss a new explanation for the population dynamics inside the Franco-Cantabrian area, based on range expansion theory. This approximation to previously contradictory findings has made them compatible with most proposals about the postglacial resettlement of Western Europe.

Time-Variable Gravity from Space: Quarter Century of Observations, Mysteries, and Prospects

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2003-01-01

Any large mass transport in the Earth system produces changes in the gravity field. Via the space geodetic technique of satellite-laser ranging in the last quarter century, the Earth s dynamic oblateness J2 (the lowest-degree harmonic component of the gravity field) has been observed to undergo a slight decrease - until around 1998, when it switched quite suddenly to an increase trend which has continued to date. The secular decrease in J2 has long been attributed primarily to the post-glacial rebound in the mantle; the present increase signifies an even larger change in global mass distribution whose J2 effect overshadows that of the post-glacial rebound, at least over interannual timescales. Intriguing evidences have been found in the ocean water distribution, especially in the extratropical Pacific basins, that may be responsible for this 52 change. New techniques based on satellite-to-satellite tracking will yield greatly improved observations for time-variable gravity, with much higher precision and spatial resolution @e., much higher harmonic degrees). The most important example is the GRACE mission launched in March 2002, following the success of the CHAMP mission. Such observations are becoming a new and powerful tool for remote sensing of geophysical fluid processes that involve larger-scale mass transports.

Replicate phylogenies and post-glacial range expansion of the pitcher-plant mosquito, Wyeomyia smithii, in North America.

PubMed

Merz, Clayton; Catchen, Julian M; Hanson-Smith, Victor; Emerson, Kevin J; Bradshaw, William E; Holzapfel, Christina M

2013-01-01

Herein we tested the repeatability of phylogenetic inference based on high throughput sequencing by increased taxon sampling using our previously published techniques in the pitcher-plant mosquito, Wyeomyia smithii in North America. We sampled 25 natural populations drawn from different localities nearby 21 previous collection localities and used these new data to construct a second, independent phylogeny, expressly to test the reproducibility of phylogenetic patterns. Comparison of trees between the two data sets based on both maximum parsimony and maximum likelihood with Bayesian posterior probabilities showed close correspondence in the grouping of the most southern populations into clear clades. However, discrepancies emerged, particularly in the middle of W. smithii's current range near the previous maximum extent of the Laurentide Ice Sheet, especially concerning the most recent common ancestor to mountain and northern populations. Combining all 46 populations from both studies into a single maximum parsimony tree and taking into account the post-glacial historical biogeography of associated flora provided an improved picture of W. smithii's range expansion in North America. In a more general sense, we propose that extensive taxon sampling, especially in areas of known geological disruption is key to a comprehensive approach to phylogenetics that leads to biologically meaningful phylogenetic inference.

Global ocean conveyor lowers extinction risk in the deep sea

USGS Publications Warehouse

Henry, Lea-Anne; Frank, Norbert; Hebbeln, Dierk; Weinberg, Claudia; Robinson, Laura; van de Flierdt, Tina; Dahl, Mikael; Douarin, Melanie; Morrison, Cheryl L.; Correa, Matthias Lopez; Rogers, Alex D.; Ruckelshausen, Mario; Roberts, J. Murray

2014-01-01

General paradigms of species extinction risk are urgently needed as global habitat loss and rapid climate change threaten Earth with what could be its sixth mass extinction. Using the stony coral Lophelia pertusa as a model organism with the potential for wide larval dispersal, we investigated how the global ocean conveyor drove an unprecedented post-glacial range expansion in Earth׳s largest biome, the deep sea. We compiled a unique ocean-scale dataset of published radiocarbon and uranium-series dates of fossil corals, the sedimentary protactinium–thorium record of Atlantic meridional overturning circulation (AMOC) strength, authigenic neodymium and lead isotopic ratios of circulation pathways, and coral biogeography, and integrated new Bayesian estimates of historic gene flow. Our compilation shows how the export of Southern Ocean and Mediterranean waters after the Younger Dryas 11.6 kyr ago simultaneously triggered two dispersal events in the western and eastern Atlantic respectively. Each pathway injected larvae from refugia into ocean currents powered by a re-invigorated AMOC that led to the fastest postglacial range expansion ever recorded, covering 7500 km in under 400 years. In addition to its role in modulating global climate, our study illuminates how the ocean conveyor creates broad geographic ranges that lower extinction risk in the deep sea.

Re-Os geochronology and coupled Os-Sr isotope constraints on the Sturtian snowball Earth.

PubMed

Rooney, Alan D; Macdonald, Francis A; Strauss, Justin V; Dudás, Francis Ö; Hallmann, Christian; Selby, David

2014-01-07

After nearly a billion years with no evidence for glaciation, ice advanced to equatorial latitudes at least twice between 717 and 635 Mya. Although the initiation mechanism of these Neoproterozoic Snowball Earth events has remained a mystery, the broad synchronicity of rifting of the supercontinent Rodinia, the emplacement of large igneous provinces at low latitude, and the onset of the Sturtian glaciation has suggested a tectonic forcing. We present unique Re-Os geochronology and high-resolution Os and Sr isotope profiles bracketing Sturtian-age glacial deposits of the Rapitan Group in northwest Canada. Coupled with existing U-Pb dates, the postglacial Re-Os date of 662.4 ± 3.9 Mya represents direct geochronological constraints for both the onset and demise of a Cryogenian glaciation from the same continental margin and suggests a 55-My duration of the Sturtian glacial epoch. The Os and Sr isotope data allow us to assess the relative weathering input of old radiogenic crust and more juvenile, mantle-derived substrate. The preglacial isotopic signals are consistent with an enhanced contribution of juvenile material to the oceans and glacial initiation through enhanced global weatherability. In contrast, postglacial strata feature radiogenic Os and Sr isotope compositions indicative of extensive glacial scouring of the continents and intense silicate weathering in a post-Snowball Earth hothouse.

Differences in delta13C and diameter growth among remnant Scots pine populations in Scotland.

PubMed

Brendel, Oliver; Handley, Linda; Griffiths, Howard

2002-10-01

Published data suggest that differences in wood cellulose carbon isotope composition (delta13C) and xylem ring width among natural populations of Scots pine in Scotland (Pinus sylvestris L.) are attributable to the persistence of palaeotypes of various post-glacial migratory origins. We assessed differences in wood cellulose delta13C and ring width among Scottish Scots pine populations grown in a clone bank and in natural stands at various locations in northern and central Scotland. Ring width and wood cellulose delta13C varied significantly among natural stands. Potential water deficit was positively correlated with wood cellulose delta13C and xylem ring width in the natural stands. Neither wood cellulose delta13C nor xylem ring width of clone bank trees correlated with any climate variables at the sites from which the trees originated, indicating little adaptation to climate for these traits. Xylem ring width showed a site x population interaction for the growth sites (i.e., natural stands versus clone bank), but wood cellulose delta13C did not. These results suggest that climate variation in Scotland has not resulted in significant genetic variation in wood cellulose delta13C or xylem ring width in post-glacial populations.