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1.
The food selectivity of tethered females of the copepodCalanus helgolandicus was examined by using the colorimetric approach. First, feeding behavior of the copepod did not show any differences between
the red-color stained with neutral red and non-stained diets using the diatomCoscinodiscus curvatulus. Then, the copepods were fed a mixtures of two diets, the diatomC. curvatulus, stained with neutral red, and the dinoflagellateGymnodinium sanguineum for 14~60 minutes of feeding duration. The foregut colors of females were examined using a stereo-microscope and a video
monitor. The foreguts of animals fed with a high density of diatoms in mixed diets showed a dark red color, whereas those
fed with a high density of dinoflagellate in mixed diets were a dark yellow. The results suggest that this species of copepod
may not selectively feed either one of the diets used for this study. Their feeding activity may be more likely related to
the density of available prey in their environment. Therefore, this quick and easy colorimetric approach could provide very
useful information, like the pre-screening procedure before designing and conducting the time-consuming and complex feeding
experiments to understand the feeding ecology of copepods. 相似文献
2.
The Amur River’s influence on the distribution of the opportunistic bacteria Listeria monocytogenes in the western part of the Sea of Okhotsk is discussed. The presence of Listeria in the seawater, sea ice, and sediments
on the northeastern Sakhalin shelf and slope supports the idea of its connection with the Amur River discharge. The hypothesis
of the allochtonic parentage of L. monocytogenes in the sea’s development is proved. 相似文献
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We present the results of experimental investigations of the characteristics of turbulence in the layer of wave-induced mixing.
The data on the fluctuations of velocity, temperature, and conductivity are obtained with the help of a Sigma-1 measuring complex. The computed values of the dissipation rate of turbulent energy are compared with different models proposed
for the subsurface layer. It is shown that the available models fail to guarantee satisfactory agreement of the numerical
results with the experimental data for the layer of active wave action and, in particular, in the presence of swell. This
leads us to the conclusion concerning the necessity of parametrization and assimilation of more complete data on the state
of the sea surface, the structure of currents, and the surface layer of the atmosphere in the models.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 15–28, March–April, 2007. 相似文献
6.
Based on new and existing data on oxygen isotopes, alkenone-surface seawater temperature trends, planktonic foraminifers,
lithology, and clay mineral composition of piston cores, a distinct cooling event has been identified around 8,200 cal a b.p. in the middle Okinawa Trough, northwest Pacific. This corresponds to the 8,200 a b.p. cooling event recorded in many places of the Northern Hemisphere. During this event, the local temperature decreased by
1°C, and the δ18O value increased by 0.6‰. A strengthened Asian winter monsoon is the most probable cause for this event, which thus adds
further credibility to the contention that we are dealing here with a global phenomenon. 相似文献
7.
B. A. Kagan A. A. Timofeev E. H. A. Rashidi 《Izvestiya Atmospheric and Oceanic Physics》2012,48(4):432-443
To find variations in the dynamics of the surface M 2 tide in the White Sea induced by the spatially inhomogeneity of the resistance coefficient, we use a modified version of the QUODDY-4 three-dimensional finite-element hydrostatic model. This version differs from the original version in that it has a module introduced to calculate the resistance coefficient in the bottom boundary layer (BBL). The resistance coefficient is found from resistance laws for an oscillating rotating turbulent BBL over hydrodynamically rough and partially rough (smoothly rough) underlying surfaces describing the dependence of the resistance coefficient and other integral characteristics of resistance on dimensionless similarity parameters: the sea-bottom Rossby number Ro, the streaming Reynolds number Re, and the relative (normalized to tidal frequency) inertial frequency f/σ. The use of spatial inhomogeneity of the resistance coefficient was shown not to lead to considerable changes in tidal characteristics. The values of these characteristics are several times larger than the instrumental measurement errors for the level and velocity but less than the errors in their calculation. 相似文献
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S. N. Moshonkin V. B. Zalesny A. V. Gusev 《Izvestiya Atmospheric and Oceanic Physics》2018,54(5):495-506
The algorithm for splitting k–ω turbulence equations is used to parameterize viscosity and diffusion coefficients in the ocean general circulation model. The k–ω equations are split into stages describing the transport-diffusion and generation-dissipation of the turbulent kinetic energy and frequency function ω. At the generation-dissipation stage, the equations are solved analytically. Calculations of circulation in the North Atlantic–Arctic Ocean for 1948–2009 have been carried out. The experiments demonstrate an adequate reproduction of hydrophysical characteristics and high efficiency of the algorithm. It is shown that considering the climatic annual mean buoyancy frequency in the turbulence equations at the generation-dissipation stage is an important factor in improving the accuracy of simulated fields. 相似文献
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Soo Woon Kim Sam Moon Kim Dong Kun Lee Hyo Bang Moon Hee Gu Choi Chang Keun Kang Eun Sang Choe 《Ocean Science Journal》2007,42(2):129-134
Increasing industrial development in the Masan Bay area of Korea over the past decades increased the risk for the survival
of marine organisms in the bay area by the deterioration of the water quality. Since living organisms have the ability to
adapt contamination-associated stimuli by the alteration of gene expression, changes in proteins can be used as an important
criterion for assessing the levels of environmental conditions. In this study, therefore, alterations of the expression of
proteins in the muscle ofLimanda yokohamae from Dukdong and Dotsum in the bay area were surveyed and characterized as compared with Haegumgang, which served as a control
site. The results demonstrated that the twenty spots detected from Dukdong and Dotsum were similar to each other. Fifteen
proteins were found to be predicted or undefined proteins, while five proteins were identified as heavy polypeptide 11 of
myosin, apolipoprotein A-I, fibroblast growth factor 17b precursor, G protein-coupled receptor kinase 1 b and bonnie and clyde.
These data suggest that local fish in the bay area have dysfunction in muscle physiology including contraction, lipid metabolism,
proliferation and differentiation and nervous system. 相似文献
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Seok Lee Heung-Jae Lie Cheol-Ho Cho Sok Kuh Kang William J. Teague Kyung-Il Chang Kyu-Min Song Kyung-Hee Oh 《Ocean Science Journal》2011,46(2):73-84
The vertical structure of the M2 tidal current in the Yellow Sea is analyzed from data acquired using an acoustic Doppler current profiler. The observed vertical
profiles of the M2 tidal current are decomposed into two rotating components of counter-clockwise and clockwise, and restructured using a simple
one-point model with a constant vertical eddy viscosity. The analyzed results show that the internal fictional effect dominates
the vertical structure of the tidal current in the bottom boundary layer. In the Yellow Sea, the effect of the bottom friction
reduces the current speed by about 20–40% and induces the bottom phase advance by about 15–50 minutes. In the shallower coastal
regions, the effects of bottom topography are more prominent on the vertical structure of tidal currents. The vertical profile
of the tidal current in summer, when the water column is strongly stratified, is disturbed near the pycnocline layer. The
stratification significantly influences the vertical shear and distinct seasonal variation of the tidal current. 相似文献
15.
We measured the ammonium excretion, phosphate excretion and respiration rates of the scyphomedusa Aurelia aurita from Ondo Strait, in the central part of the Inland Sea of Japan, at 28 and 20°C. The rates measured at 28°C were converted
to those at 20°C using the Q10 values, i.e. 1.56, 1.57 and 2.80, for ammonium excretion, phosphate excretion and respiration rates, respectively. The composite
relationships between metabolic rates and wet weight of a medusa (WW, g, range 11–1330 g) at 20°C were expressed by the following allometric equations. For ammonium excretion rate (N, μmoles N medusa−1d−1): N = 0.497WW
1.09, phosphate excretion rate (P, μmoles P medusa−1d−1): P = 0.453WW
0.84, and respiration rate (R, μmoles O2 medusa−1d−1): R = 96.9WW
1.06. Mean O:N ratios (i.e. atomic ratios of 16.9 and 11.0 at 28 and 20°C, respectively) indicated that the metabolism of A. aurita medusae was protein-dominated. These metabolic parameters enabled us to estimate the nitrogen and phosphorus regeneration
rates of an A. aurita medusa population typical of early summer in the Ondo Strait (means of water temperature, medusa individual weight and population
biomass: 20°C, 200 g WW and 50.8 g WW m−3, respectively). Regenerated nitrogen and phosphorus were equivalent to 10.0 and 21.6% of phytoplankton uptake rates, respectively,
nearly twice that estimated for mesozooplankton, demonstrating that A. aurita medusae are key components of the plankton community, influencing the trophic and nutrient dynamics in the Ondo Strait during
early summer. 相似文献
16.
The surface M
2 tide in the Canadian Arctic Archipelago (CAA) is reproduced on the basis of the QUODDY-4 three-dimensional finite-element
hydrodynamic model. Particular emphasis has been placed on comparing model estimates for the amplitudes and phases of tidal
elevations and the parameters of ellipses (major semiaxis and eccentricity) of the barotropic tidal current velocity with
observational data. We present their spatial distributions and the distributions of averaged (over a tidal cycle) values of
the density, horizontal transfer, and dissipation rate of barotropic tidal energy. It is found that the CAA is a much less
effective dissipator of barotropic tidal energy than the World Ocean. 相似文献
17.
The ecological consequences of ocean acidification are unclear due to varying physiological properties of macroalgae and species-specific responses. Therefore, in the present study, we used a laboratory culture experiment to analyse the eco-physiological responses of the Mediterranean subtidal red alga Peyssonnelia squamaria to CO2-induced lower pH. Our results showed an increase in the photosynthetic performance and growth rate of P. squamaria, despite the reduction in CaCO3 content in the low pH treatment. According to our results, we believe that samples exposed to elevated CO2 could be regulated own nitrogen metabolism to support increased growth rate and it may be down-regulated nitrate uptake. As a result, we hypothesize that P. squamaria may benefit from ocean acidification. 相似文献
18.
E. M. Lemeshko A. N. Morozov S. V. Stanichnyi L. D. Mee G. I. Shapiro 《Physical Oceanography》2008,18(6):319-331
The profiles of absolute current velocity obtained by using a lowered acoustic doppler current profiler (LADCP) are presented. In the course of the BSERP-3 expedition, the measurements were carried out in the regions of the Rim Current, anticyclonic eddy, and northwest shelf.
In the core of the Rim Current, a unidirectional motion of waters is traced in layers below the main pycnocline down to depths
greater than 500 m. Its characteristic velocity can be as high as 0.08 m/sec. It is shown that the direct action of the eddy
is detected in the shelf region at distances larger than 20 km from the outer edge of the shelf in the zone bounded by an
isobath of 100 m. The formation of multilayer vertical structures in the field of current velocities is revealed in the region
of interaction of the anticyclonic eddy with irregularities of the bottom on the side of the shelf. A two-layer structure
of currents with specific features in the layer of formed seasonal pycnocline is observed in the region of the shelf down
to an isobath of 100 m. The profiles of the moduli of vertical shears of currents averaged over the casts ensemble are presented
for the abyssal and shelf parts of the sea. It is shown that the shears induced by the geostrophic currents and wave processes
in the region of the main pycnocline are comparable. Below the pycnocline, the shears are mainly determined by the wave processes.
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 25–37, November–December, 2008. 相似文献
19.
Long-term investment to drive the adoption of precautionary, adaptive and resilience-building fisheries management measures is urgently required, especially given the financially difficult transition period to reach sustainable fisheries. In this paper a case for investing in the recovery of large marine ecosystems is provided based on the future value of recovered fish stocks. It is argued that the current market-based sustainable seafood movement alone will not affect the scale of change needed and must be complemented by investment in fundamental conservation measures that will lead to the recovery of marine ecosystems and promote long-term sustainable use. A rationale for addressing the economically challenging transition period is provided and the basis of a new financial institution to finance the measures necessary for realising the economic, social and environmental benefits of large-scale fisheries reform is proposed. 相似文献
20.
S. A. Mosharov 《Oceanology》2010,50(6):884-892
The studies were performed from September 10 to 29 of 2007 in the Kara Sea in transects westward of the Yamal Peninsula, near
the St. Anna Trough, in the Ob River’s estuary, and on the adjacent shelf. The concentration of chlorophyll a in the euphotic layer changed from 0.02 to 4.37 mg/m3, amounting on the average to 0.76 mg/m3. The primary production in the water column varied from 10.9 to 148.0 mg C/m2 per day (the mean was 56.9 mg C/m2 per day). It was shown that frontal zones divided the Kara Sea into distinct areas with different productivities. The maximum
levels of the primary production were measured in the deep part of the Yamal transect (132.4 mg C/m2 per day) and the shallow Kara Sea shelf near the Ob River’s estuary (74.9 mg C/m2 per day). The characteristics of these regions were the low salinity of the surface water layer (19–25 psu) and the elevated
silicon content (12.8–28.1 μg-atom Si/l), which is explainable by the river water inflow. The frontal zones of the Yamal Current
in the Yamal and Ob transects displayed high values of the assimilation numbers, amounting to 2.32 and 1.49 mg C/mg of chlorophyll
per h, respectively (the maximal for the studied regions). 相似文献