Element composition of ferromanganese concretions in the Black Sea     

G. N. Baturin 《Oceanology》2010,50(1):83-92

The ferromanganese concretions spread at the bottom of the shallow northwestern part of the Black Sea are mainly represented by Fe and Mn hydrate nodules on shells and substituted worm tubes. The element composition of these formations was found by the methods of chemical, atomic-absorbtion, neutron activation, and plasmic (ICP-MS) analyses. It is established that the content and the ratio of Fe and Mn in the concretions ranges within considerable limits, which controls the occurrence of several associated iron-free metals and microelements, some which have not been previously studied in the Black Sea concretions.  相似文献   

What meta-analysis can tell us about vulnerability of marine biodiversity to ocean acidification?     

S. Dupont  N. Dorey  M. Thorndyke 《Estuarine, Coastal and Shelf Science》2010

Ocean acidification has been proposed as a major threat for marine biodiversity. Hendriks et al. [Hendriks, I.E., Duarte, C.M., Alvarez, M., 2010. Vulnerability of marine biodiversity to ocean acidification: a meta-analysis. Estuarine, Coastal and Shelf Science, doi:10.1016/j.ecss.2009.11.022.] proposed an alternative view and suggested, based on a meta-analysis, that marine biota may be far more resistant to ocean acidification than hitherto believed. However, such a meta-analytical approach can mask more subtle features, for example differing sensitivities during the life-cycle of an organism. Using a similar metric on an echinoderm database, we show that key bottlenecks present in the life-cycle (e.g. larvae being more vulnerable than adults) and responsible for driving the whole species response may be hidden in a global meta-analysis. Our data illustrate that any ecological meta-analysis should be hypothesis driven, taking into account the complexity of biological systems, including all life-cycle stages and key biological processes. Available data allow us to conclude that near-future ocean acidification can/will have dramatic negative impact on some marine species, including echinoderms, with likely consequences at the ecosystem level.  相似文献   

Long-term changes in the meiobenthos of the eastern part of the Black Sea     

V. O. Mokievsky  L. V. Vorobjeva  L. A. Garlitska  M. A. Miljutina  N. V. Kucheruk 《Oceanology》2010,50(6):945-952

The results of meiobenthic surveys undertaken in 1991, 1999, and 2005 off the Caucasian coasts of the Black Sea are presented. During the period of 1991 to 1999, the number of free-living nematodes increased significantly at all the sampling stations. The mean nematode abundance values grew from 85 ind./10 cm² in 1991 to 1167 ind./10 cm² in 1999. Proportionally, the total metazoan meiofauna density increased from 171 to 1283 ind./10 cm². The abundance of other meiofaunal groups including harpacticoid copepods did not change significantly. As a result of these changes, the ratio of nematodes to copepods (the nematodes-copepods index) increased from 2.5: 1 in 1991 to 26: 1 in 1999 and to 70: 1 in 2005. The number of foraminifers increased twofold. In 1991, they were found only at five stations out of 25. In 1999, foraminifers were presented at all ten stations with a mean density of 212 ind./10 cm². Such changes in the meiobenthic communities could have resulted from cascade transformations of the ecosystem leading to among other changes to a decline in the macrobenthos biomass and the release of nonutilized organic matter in the bottom ecosystems. The differences in the procedures of the sampling and the samples’ processing in the different years may be responsible for the 20–30% variation in the assessment of the meiobenthos’ number.  相似文献   

Optical characteristics of coastal waters and atmosphere near the south coast of the crimea at the end of summer 2008     

V. I. Man’kovskii  G. A. Tolkachenko  E. B. Shibanov  O. V. Martynov  E. N. Korchemkina  D. V. Yakovleva  I. A. Kalinskii 《Physical Oceanography》2010,20(3):207-230

We present the results of measurements of optical characteristics of waters (the beam attenuation coefficient, volume scattering function, sea water reflectance, and Secchi depth) and optical characteristics of the atmosphere (aerosol optical thickness, content of vapors, and the ?ngstr?m exponent) carried out in September 2008 on the oceanographic platform near Katsiveli. We carried out the comparative analysis of hydrooptical characteristics measured in various years. The optical type of sea waters in the period of observations is determined.  相似文献   

Stratigraphy and formation conditions of the sedimentary cover in the Sea of Japan near the Bogorov Rise     

V. N. Karnaukh  I. B. Tsoy 《Oceanology》2010,50(4):556-572

The results of the complex study of the sedimentary cover (continuous seismic profiling and diatom analysis) in the northeastern part of the Sea of Japan, including the Bogorov Rise, the adjacent part of the Japan Basin, and the continental slope, are presented. Two varied-age complexes were distinguished in the sedimentary cover of Primorye’s continental slope, namely, the Middle Miocene and Late Miocene-Pleistocene; these complexes were formed in a stable tectonic environment with no significant vertical movements. The depression in the acoustic basement is located along the continental slope and it is divided from the Japan Basin by a group of volcanic structures, the most uplifted part of which forms the Bogorov Rise. The depression was formed, probably, before the Middle Miocene. In the Middle Miocene, the Bogorov Rise was already at the depths close to the modern ones. In the sedimentary cover near the Bogorov Rise, buried zones were found, which probably were channels for gas transportation in the pre-Pleistocene. Deformations of sediments that occurred in the beginning of the Pleistocene are established in the basin.  相似文献   

Field studies of variation scales of gravitational capillary waves and near-water wind in the Black Sea shelf area     

V. V. Bakhanov  N. A. Bogatov  A. S. Volkov  A. V. Ermoshkin  E. M. Zuykova  V. I. Kazakov  O. N. Kemarskaya  V. N. Lobanova  I. A. Repina  V. I. Titov 《Izvestiya Atmospheric and Oceanic Physics》2010,46(2):232-238

In this study we present the results of data processing from the 2004 Gelendzhik Bay expedition on the Akvanavt research vessel. The data were processed using the method of wavelet analysis. We found an emerging kilometer-scale variation in the surface heaving and near-water wave over the shelf area. This effect was shown to be possibly caused by the inhomogeneity of current in the depth-drop area.  相似文献   

Baroclinic seiches in rotating basins of variable depth in the case of two-layer density stratification     

S. F. Dotsenko  N. A. Miklashevskaya 《Physical Oceanography》2010,20(3):157-169

We solve a plane problem of linear baroclinic seiches in closed rotating basins of variable depth with two-layer density stratification. In the long-wave approximation, we get a boundary-value problem for a system of ordinary differential equations and propose a numerical procedure for finding internal seiches. The analytic solutions of the problem are obtained for a basin of constant depth. The numerical analysis of seiches is performed for the distributions of depth corresponding to the zonal and meridional sections of the Black Sea and model basins including the cases of a shelf zone and an underwater ridge. It is shown that the baroclinic seiches become more intense in shallow-water regions and that the intense longshore currents caused by Earth’s rotation are formed in the shelf zones and over the underwater ridges.  相似文献   

Coastal observatory for long-term measurement and real time data processing of oceanological parameters     

S. A. Sviridov  N. A. Palshin  V. A. Solovyev  A. V. Zaretskiy  A. A. Metal’nikov 《Oceanology》2010,50(1):139-147

A coastal observatory for long-term continuous measurements of oceanological parameters and real-time data transfer via the Internet to remote users is described. The observatory was designed at the Shirshov Institute of Oceanology (SIO) and tested at its southern branch (SB) in the Black Sea. The architecture, components, and design principles of the observatory are discussed along with its application for solving problems of water dynamics in the coastal zone. Results of field tests are given.  相似文献   

Impact of hydrographic parameters and seasonal variation in sediment fluxes on coral status at Chumbe and Bawe reefs,Zanzibar, Tanzania     

Alfred N.N. Muzuka  Alfonse M. DubiChristopher A. Muhando  Yohanna W. Shaghude 《Estuarine, Coastal and Shelf Science》2010

Coral reefs which are an important resource to coastal communities and nation at large are adversely affected by rate of sediment flux to the reefs. However, there is little information on seasonal trend in sediment flux and its impact at the reefs off Zanzibar. Two years’ monthly data on sedimentation at Chumbe and Bawe reefs were used to assess seasonal variability in sediment flux and its implication on the coral status. Sediment flux to the Bawe reefs for the duration of the study ranged from 0.2 to 41.5 mg cm⁻² d⁻¹, while it ranged from 0.8 to 65.8 mg cm⁻² d⁻¹ at the Chumbe reefs. Sediment fluxes at Bawe reefs were highest between November and March, while they were highest between April and September at Chumbe reefs. Generally, sediment fluxes at Bawe reefs were low compared to those at Chumbe. The total sediment input to the reefs ranged from 4615 to 123,403 kg d⁻¹ for Bawe reefs and 2750 to 79,636 kg d⁻¹ for Chumbe reefs. High sediment fluxes at Bawe reefs between November and March; and the Chumbe reefs between April and September can be attributed to water currents and wind pattern in the east African region which are under the influence of the monsoons. The observed trend suggests that the period for coral transplant as a management option for the two sites should be different. Coral transplant can be undertaken in such a way that stress of the corals due to sedimentation can be felt after they have overcome stress from transplant process and temperature. The results from this study contribute to the much needed information for coral transplant, restoration, and management.  相似文献   

A field test of a linear stability model for crescentic bars     

M.C.H. Tiessen  S.M. van Leeuwen  D. Calvete  N. Dodd 《Coastal Engineering》2010

A morphodynamical linear stability analysis is used to predict the natural development of crescentic bed patterns and rip channels. The purpose is to investigate whether this technique, which is useful for understanding the physics of emerging bed-forms, can be used to make quantitative predictions in the field, which may then be of use for coastal engineers.  相似文献