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931.
Zavialov P. O. Zavialov I. B. Izhitskiy A. S. Izhitskaya E. S. Konovalov B. V. Krementskiy V. V. Nemirovskaya I. A. Chasovnikov V. K. 《Oceanology》2022,62(2):162-170
Oceanology - The paper presents the results of an analysis of the main pollutants (heavy metals, pesticides, detergents, hydrocarbons) in water, suspended particulate matter, and bottom sediments,... 相似文献
932.
Pockmarks in the inner Oslofjord,Norway 总被引:2,自引:3,他引:2
Multibeam bathymetric surveys of the Inner Oslofjord, Norway have revealed a high density of pockmarks in the 179-km2 inner fjord area, which contains over 500 pockmarks of varying size, typically 20–50 m in diameter and 2–10 m deep. These
pockmarks have been investigated with a variety of techniques, including acoustic subbottom profiling, sedimentological and
geochemical analyses of cores, remotely operated vehicle observation, and morphometry. Both the distribution and shapes of
the pockmarks suggest that they are related to structures in the bedrock underlying relatively thin (<50 m) unconsolidated
glacial and postglacial sediments. The data provide no direct indication of a particular mode of pockmark formation, but release
of large amounts of biogenic, shallow methane seems unlikely. Several lines of evidence point to a continuous process of pockmark
formation followed by inactivity, with some pockmarks recently active whereas others have been inactive for a considerable
time. Some pockmarks are characterised by coarse sediment in their centres. The density, variety and easy access make this
pockmark field an ideal model area for pockmark research.
John S. Gray is deceased. 相似文献
933.
This paper documents a new method for describing channel-related sedimentary deposits based on formal language theory. Using this method an analogue model of a sedimentary deposit can be encoded as a grammar. A program, called a parser, has been developed which can generate stochastic maps of these sedimentary deposits based on information in a specified grammar. The maps of sedimentary deposits generated by the parser have the same type, spatial arrangement, shape and size distribution as the analogue model. The successful generation of depositional maps represents a crucial step in the ongoing development of a new technique designed to generate 3D static geological models of sedimentary successions. The maps can be conditioned to match sparse hard data in the form of channel segments interpreted from seismic horizon maps. 相似文献
934.
Molecular organic biomarkers together with trace element composition were investigated in sediments east of Barrow Canyon in the western Arctic Ocean to determine sources and recycling of organic carbon in a continuum from the shelf to the basin. Algal biomarkers (polyunsaturated and short-chain saturated fatty acids, 24-methylcholesta-5,24(28)-dien-3β-ol, dinosterol) highlight the substantial contribution of organic matter from water column and sea-ice primary productivity in shelf environments, while redox markers such as acid volatile sulfide (AVS), Mn, and Re indicate intense metabolism of this material leading to sediment anoxia. Shelf sediments also receive considerable inputs from terrestrial organic carbon, with biomarker composition suggesting the presence of multiple pools of terrestrial organic matter segregated by age/lability or hydrodynamic sorting. Sedimentary metabolism was not as intense in slope sediments as on the shelf; however, sufficient labile organic matter is present to create suboxic and anoxic conditions, at least intermittently, as organic matter is focused towards the slope. Basin sediments also showed evidence for episodic delivery of labile organic carbon inputs despite the strong physical controls of water depth and sea-ice cover. Principal components analysis of the lipid biomarker data was used to estimate fractions of preserved recalcitrant (of terrestrial origin) and labile (of marine origin) organic matter in the sediments, with ranges of 12–79%, 14–45%, and 37–66% found for the shelf, slope, and basin cores, respectively. On average, the relative preserved terrestrial organic matter in basin sediments was 56%, suggesting exchange of organic carbon between nearshore and basin environments in the western Arctic. 相似文献
935.
Dissolved aluminium and the silicon cycle in the Arctic Ocean 总被引:1,自引:0,他引:1
Concentrations of dissolved (0.2 µm filtered) aluminium (Al) have been determined for the first time in the Eurasian part of the Arctic Ocean over the entire water column during expedition ARK XXII/2 aboard R.V. Polarstern (2007). An unprecedented number of 666 samples was analysed for 44 stations along 5 ocean transects. Dissolved Al in surface layer water (SLW) was very low, close to 1 nM, with lowest SLW concentrations towards the Canadian part of the Arctic Ocean and higher values adjacent to and in the shelf seas. The low SLW concentrations indicate no or little influence from aeolian dust input. Dissolved Al showed a nutrient-type increase with depth up to 28 nM, but large differences existed between the different deep Arctic basins. The differences in concentrations of Al between water masses and basins could largely be related to the different origins of the water masses. In the SLW and intermediate water layers, Atlantic and Pacific inflows were of importance. Deep shelf convection appeared to influence the Al distribution in the deep Eurasian Basin. The Al distribution of the deep Makarov Basin provides evidence for Eurasian Basin water inflow into the deep Makarov Basin. A strong correlation between Al and Silicon (Si) was observed in all basins. This correlation and the nutrient-like profile indicate a strong biological influence on the cycling and distribution of Al. The biological influence can be direct by the incorporation of Al in biogenic silica, indirect by preferential scavenging of Al onto biogenic siliceous particles, or by a combination of both processes. From the slope of the overall Al–Si relationship in the intermediate water layer (AIDW; ~ 200–2000 m depth), an Al/Si ratio of 2.2 atoms Al per 1000 atoms Si was derived. This ratio is consistent with the range of previously reported Al/Si uptake ratio in biogenic opal frustules of diatoms. In the deepest waters (>2000 m depth) a steeper slope of the Al–Si relationship of 7.4 to 13 atoms Al per 1000 atoms Si likely results from entrainment of cold shelf water into the deep basins, carrying the signal of dissolution of terrigenous particles with a much higher Al:Si ratio of crustal abundance. Only a small enrichment with such crustal Al and Si component may readily account for the higher Al:Si slope in the deepest waters. 相似文献
936.
Taro Takahashi Stewart C. Sutherland Rik Wanninkhof Colm Sweeney Richard A. Feely David W. Chipman Burke Hales Gernot Friederich Francisco Chavez Christopher Sabine Andrew Watson Dorothee C.E. Bakker Ute Schuster Nicolas Metzl Hisayuki Yoshikawa-Inoue Masao Ishii Takashi Midorikawa Yukihiro Nojiri Arne Krtzinger Tobias Steinhoff Mario Hoppema Jon Olafsson Thorarinn S. Arnarson Bronte Tilbrook Truls Johannessen Are Olsen Richard Bellerby C.S. Wong Bruno Delille N.R. Bates Hein J.W. de Baar 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2075-2076
937.
Benjamin C. Green David J. Smith Sarah E. Earley Leanne J. Hepburn Graham J.C. Underwood 《Estuarine, Coastal and Shelf Science》2009,85(2):247-256
European intertidal salt marshes are important nursery sites for juvenile fish and crustaceans. Due to the increasing threat of habitat loss, the seasonal changes of salt marsh fish communities need to be understood in order to appreciate the ecological and economic importance of the saltmarsh habitat. This study was the first in Great Britain to investigate the seasonal changes of salt marsh fish communities and the variation in community structure between closely located marsh habitats. Between February 2007 and March 2008, five marshes on three estuaries of the Essex coastline were sampled using flume nets to block off intertidal creeks at high tide. Fourteen fish species were caught. The community overall was dominated by three species that made up 91.6% of the total catch: the common goby Pomatoschistus microps (46.2% of the total catch), juvenile herring Clupea harengus (24.3%), and juvenile and larval sea bass Dicentrarchus labrax (21.2%). Cluster analysis demonstrated clear seasonal patterns, with some community structures unique to specific marshes or estuaries. The marsh fish community shifts from a highly diverse community during spring, to a community dominated by D. labrax and P. microps in autumn, and low diversity during winter months. Gravimetric stomach content analysis of fish community identified three main trophic guilds; macroinvertivores, planktivores and omnivores. The macroinvertivore feeding guild contained D. labrax and P. microps, the two most frequently occurring species. This investigation demonstrates the importance of British salt marshes as nursery habitats for commercial fish species. 相似文献
938.
The data of beam propagation of internal waves into the ocean are confirmed by several analytical solutions of the linear
long wave theory. The obtained solutions are applied to calculate the mode of the internal waves. 相似文献
939.
K. E. Muryshev A. V. Eliseev I. I. Mokhov N. A. Diansky 《Izvestiya Atmospheric and Oceanic Physics》2009,45(4):416-433
A new version of the Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), climate model (CM) has been
developed using an ocean general circulation model instead of the statistical-dynamical ocean model applied in the previous
version. The spatial resolution of the new ocean model is 3° in latitude and 5° in longitude, with 25 unevenly spaced vertical
levels. In the previous version of the oceanic model, as in the atmospheric model, the horizontal resolution was 4.5° in latitude
and 6° in longitude, with four vertical levels (the upper quasi-homogeneous layer, seasonal thermocline, abyssal ocean, and
bottom friction layer). There is no correction for the heat and momentum fluxes between the atmosphere and ocean in the new
version of the IAP RAS CM. Numerical experiments with the IAP RAS CM have been performed under current initial and boundary
conditions, as well as with an increasing concentration of atmospheric carbon dioxide. The main simulated atmospheric and
oceanic fields agree quite well with observational data. The new version’s equilibrium temperature sensitivity to atmospheric
CO2 doubling was found to be 2.9 K. This value lies in the mid-range of estimates (2–4.5 K) obtained from simulations with state-of-the-art
models of different complexities. 相似文献
940.
W. Hieke A. Camerlenghi M. B. Cita G. A. Dehghani N. Fusi H. B. Hirschleber L. Mirabile C. Müller A. Polonia 《Marine Geophysical Researches》2009,30(3):161-192
In previous publications, the relationship between the Sirte Abyssal Plain as foreland and the Mediterranean Ridge as accretionary
complex was considered to be simple: the foreland is undeformed, the accretionary complex consumes the foreland, the Messinian
evaporites control the internal structure of the growing complex. The compilation of our own and published data results in
a more complex tectonic pattern and a new geodynamic interpretation. The Sirte Abyssal Plain is imprinted by extensional tectonics
which originated independently from and prior to the approaching process of accretion. The structural setting of the pre-Messinian
and Messinian Sirte Abyssal Plain is responsible for the highly variable thickness of Messinian evaporites. The foreland setting
in the Sirte Abyssal Plain also controls the internal structure of the Mediterranean Ridge, at least between the deformation
front and Bannock Basin, following sediment deformation within the accretionary wedge with a dominating inherited SW-NE orientation.
The taper angle of the post-Messinian Mediterranean Ridge is unusually small compared with other accretionary wedges. In the
studied area, within a distance of about 45 km from the deformation front, there is no appreciable dip in the décollement.
Therefore, the slope of the outer 45 km of the Mediterranean Ridge is considered to be caused only by gravitational spreading
of Messinian evaporites deposited on the slope of pre-Messinian accretionary wedge. As a consequence, the Mediterranean Ridge
underlying such slope is interpreted to belong to the foreland. The allochthonous evaporites overlie autochthonous evaporites
of the Sirte Abyssal Plain. The NE-dipping décollement (and thus of the true tectonically driven deformation front) is expected
to initiate at about the present position of Bannock Basin. The Sirte Abyssal Plain, the adjacent Cyrene Seamount and neighbouring
seafloor relief on the African continental margin are considered to be the product of tectonic segmentation of the continental
crust. 相似文献