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1.
A non-destructive temperature calibration system for expendable bathythermographs (XBT) is described. A transfer standard technique has been used to estimate XBT thermistor probe-to-probe temperature variability. One-point calibration results suggest that a standard deviation of 0.025°C is typical at 10°C. Additional calibration data from nine XBT thermistors suggest that probe-to-probe temperature variability is largest at 0°C (ca. 0.03°C) and decreases uniformly to a minimum at 30°C (ca. 0.01°C).  相似文献   

2.
利用MATLAB实时处理GPS数据   总被引：1，自引：0，他引：1  
利用MATLAB软件环境,现场接收并实时处理海上地球物理调查过程中的GPS定位数据,剔除原始数据中的跳点,处理定位误差。采用样条拟合对测线进行拟合光滑,绘制各步处理结果的图形,并将处理前后的航向、航速数据及由此计算出的Eotvos改正值绘制成的曲线进行比较,结果表明:由原始数据计算得到的定位误差较大,与实际船体航行的轨迹有一定差距,而用经过MATLAB处理后的数据计算得到的定位误差较小,航向、航速等与船体航行的真实航迹接近,由此计算出的Eotvos改正值的精度也达到了海上重力测量中Eotvos改正的要求,保证了地球物理数据的质量。  相似文献   

3.
The behavior of a long cable towed at slow speeds through the ocean depends in a complex fashion on the path followed by the towing ship relative to the water. A cable simulation program was used to characterize the response of the cable by using idealized towing ship maneuvers as input to the program. The response of the cable was noted and it was found that the behavior of the cable was strongly dependent on the fundamental period of the towing vessel maneuvers. Sinusoidal deviations of the towing ship from a straight towing track resulted in delayed and reduced excursions of the towed vehicle from the tract; the estimated response ratio varied from 0·002 to 0·800, depending both on the period of the deviations (periods ranged from 5·5 to 4·0 hr) and on the towing depth (2 or 6 km). The ship's speed was 3 km/hr. The time lag between ship motion and vehicle response was approximately 0·5 hr for the shallow case and 1·3 hr for the deep case. Simulations runs of a low dragk (faired) cable showed that the behavior of the vehicle when towed at a depth of 6 km was similar to that obtained with a conventional cable at 2 km depth. The response of the towed vehicle to a right-angle turn of the towing ship was investigated and a generalized model of the response developed. The effects of a controllable side force on the towed vehicle were also simulated and it was noted that a deviation (2-hr period) of the towed vehicle from a straight-line track could be reduced from 40 to 2 m by impressing a side force on the vehicle with an average magnitude of 150 newtons (30 lb).  相似文献   

4.
The harpacticoid copepod, Nitocra spinipes Boeck, was used as an experimental animal in a series of tests where the toxicity of different fractions (solid and soluble) of TiO2 industrial waste water was investigated. The tests were performed in brackish water (7). Water temperature was used as a variable in the fractionation of the waste water. Temperature was found to influence the acute toxicity of the waste water. LC50 values for N. spinipes were 0·087 (± 4°C), 0·105 (+ 7°C)) and 0·12% (+ 21°C) of undiluted waste water. At room temperature the animal's fecundity was affected at two intervals, one in dilutions between 0·0003% and 0·001% and the other between 0·03% and 0·3%. An acute toxicity test with the dried solid metal fraction resuspended into clean brackish water had an acute LC50 value of 7·6% of undiluted waste water. The results show that different fractions of the waste water have different harmful biological effects under different temperature conditions.  相似文献   

5.
The maximum extent of ship spraying for a medium-sized fishing trawler (MFV) of Soviet type has been considered. A simple geometrical model for generating the spray due to ship-wave collisions has been applied to determine the maximum height of the spray source above the ship deck. The maximum height of the spray source has been assumed to depend on the ship speed relative to the moving waves and an empirical constant specific to a given type of ship. A unique field data set (Kuzniecov et al., 1971) of the height of the upper limit of ice accretion on the foremast of an MFV has been used to determine the value of the empirical constant for this vessel. For documented air-sea and ship motion parameters, the trajectories of droplets hitting the upper parts of the accretion on the foremast have been calculated using the equation of droplet motion for each reported icing event.The heights of the spray source computed by the trajectory method for each case of icing were compared with the heights of the spray source determined by a correlation involving the ship speed relative to the waves and the vertical extent of spray. The best fit was obtained for an empirical constant value of 0.535.The model performance was tested using an independent data set (Sharapov, 1971) on the spraying zone of an MFV. The tests showed that this model predicts the extent of the spraying zone over the ship with satisfactory accuracy and suggest that it should be incorporated into an integrated ship icing model.Finally, the model was run for several ship speeds, headings and wind speeds to examine the effect of these parameters on the maximum height of the spray hitting the ship's foremast. It was found that this height increases with wind speed and ship speed and is maximum for ship headings of 120–130°.  相似文献   

6.
Experimental investigations on internal solitary wave (ISW) propagation and their reflection from a smooth uniform slope were conducted in a two-layered fluid system with a free surface. A 12-meter-long wave flume was in use which incorporated with: (1) a movable vertical gate for generating ISW; (2) six ultrasonic probes for measuring the fluctuation of an ISW; and (3) a steep uniform slope (from one of θ=30°, 50°, 60°, 90°, 120° and 130°) much greater than those ever published in the literature. This paper presents the wave profile properties of the ISW recorded in the flume and their nonlinear features in comparison with the existing Korteweg de Vries (KdV) and modified Korteweg-de Vries (MKdV) theories. Experimental results show that the KdV theory is suitable for most small-amplituded ISWs and MKdV theory is appropriate for the reflected ISWs from various uniform slopes. In addition, both the amplitude-based reflection coefficient and reflected energy approach a constant value asymptotically when plotted against the slope and the characteristic length ratio, respectively. The reflected wave amplitudes calculated from experimental data agree well with those reported elsewhere. The optimum reflection coefficient is found within the limit of 0.85 for wave amplitude, among the test runs from steep normal slope of 30° to inverse angle of 130°, and around 0.75 for the reflected wave energy, produced by an ISW on a vertical wall.  相似文献   

7.
The Continuous Plankton Recorder (CPR) Type I was first used in Antarctic waters during the 1925–1927 Discovery Expedition, and has been used successfully for 70 years to monitor plankton in the North Sea and North Atlantic Ocean. Sixty-five years later the CPR as a Type II version returned to Antarctic waters when the Australian Antarctic Division initiated a survey of the Southern Ocean on RSV Aurora Australis south of Australia and west to Mawson. The objectives are to study regional, seasonal, interannual and long-term variability in zooplankton abundance, species composition and community patterns, as well as the annual abundance and distribution of krill larvae. The survey covers a large area from 60°E to 160°E, and south from about 48°S to the Antarctic coast—an area of more than 14 million km2. Tows are conducted throughout the shipping season, normally September to April, but occasionally as early as July (midwinter). The large areal and temporal scale means that it is difficult to separate temporal and geographical variation in the data. Hence, CPRs are now also towed on the Japanese icebreaker Shirase in collaboration with the Japanese Antarctic programme. Shirase has a fixed route and time schedule, travelling south on 110°E in early December and north on 150°E in mid-March each year, and will serve as an important temporal reference for measuring long-term interannual variability and to help interpret the Australian data. Since 1991, over 90 tows have been made, providing over 36,000 nautical miles of records. The most successful seasons to date have been the 1997/1998, 1999/2000 and 2000/2001 austral summers with 20, 31 and 26 tows, respectively. The 1999/2000 season included a unique, nearly simultaneous three-ship crossing of the Southern Ocean along 25° 30’E, 110°E and 157°E. Typical CPR tows show very high abundance of zooplankton in the uppermost 20 m of the permanently open ocean zone between the sea-ice zone and the Sub-Antarctic Front; this is an area thought to be oligotrophic. Appendicularians and small calanoid and cyclopoid copepods dominate the plankton. By comparison the surface waters of the sea-ice zone have low species diversity and abundances. Zooplankton data, and hence distribution patterns, can be time- and geo-coded to GPS data and environmental data collected by the ships’ underway monitoring system (e.g. fluorescence, water temperature, salinity, and meteorological data).  相似文献   

8.
To identify some specific effects of organic contaminants on fisheries in an urbanized estuary we compared the reproductive success of starry flounder from San Francisco Bay with concentrations of tissue contaminants and hepatic mixed-function oxidase (MFO) activity. We found significantly lower (P < 0·05) sediment concentrations of total identified polynuclear aromatic hydrocarbons (PAHs) in the less urbanized San Pablo Bay (SP) area (Fig. 1) than in the more urbanized central bay (CB) stations (Table 1). For flounder in early gametogenesis (August and September) the SP fish (n = 20) had significantly lower (P < 0·01) liver concentrations of Aroclor 1260 (0·34 ± 0·14 μg/g) than those at the CB stations: Berkeley (BK, n = 20, 1·6 ± 1·6 μg/g); Oakland (OK, n = 16, 2·3 ± 2·8 μg/g); and Alameda (AL, n = 4, 2·2 ± 1 μg/g). A similar pattern existed for DDT concentrations: SP = 0·2 ± 0·16 μg/g; BK = 0·1 ± 0·34 μg/g; OK = 0·4 ± 0·53 μg/g; and AL = 0·4 ± 0·33 μg/g. Total PAHs in livers were as follows: SP = 0·14 μg/g; BK = 2·6 μg/g; OK = 1·4 μg/g; and AL = 14 μg/g. Although gonad index, liver index, and presence of fin rot are inversely related to aryl hydrocarbon hydroxylase (AHH) activity, healthy fish in a similar reproductive state have lower AHH activities in the SP area. For example, in August and September, 1984, mean AHH activities were as follows: SP = 203 ± 89, and CB = 355 ± 200 pmol 3-OH-B[a]P mg microsomal protein min. We found a log-linear relationship for AHH activity and its percent inhibition by 7,8-benzoflavone (10−4m) and only a few fish from SP showed enhanced AHH activity after addition of 7,8-benzoflavone. This suggests that most of the starry flounder in San Francisco Bay are induced.  相似文献   

9.
Excreted salts and leaves from the Salt Marsh Cordgrass Spartina alterniflora were collected from two different sites. One site, Piles Creek (PC), is near heavily industrialized Linden, New Jersey, USA. The other site, Big Sheepshead Creek (BSC), is located near non-industrialized Tuckerton, New Jersey, USA. PC soil concentrations of mercury were 18·17 ± 7·67 ppm, while BSC soil concentrations were 0·22 ± 0·04 ppm. Spartina leaves from PC contained 0·16 ± 0·07 ppm of mercury, and BSC leaves contained 0·02 ± 0·0 ppm. Laboratory studies showed that S. alterniflora from both sites was capable of excreting mercury. Field collected salts from PC Spartina plants contained 0·11 ± 0·02 ppm of mercury, 2·60 ± 0·52 ppm of cadmium and 11·98 ± 0·94 ppm of zinc. These levels of heavy metals were as much as five- and-a-half times the concentrations of these metals found in ambient sea salts.  相似文献   

10.
To determine the effect of low water temperature on development, walleye pollock (Theragra chalcogramma) eggs from the Bering Sea were reared at −0.6°C, 0.4°C, 2.0°C, and 3.8°C. One group of eggs was reared at 3.9°C under a diel light cycle (14 h light, 10 h dark) to observe the effect of light on development and hatching. Development was normal for all temperatures except −0.6°C; abnormal development of the tail and lack of development of eyes occurred in some embryos. Time to 50% hatch was 820, 620, and 424 h at 0.4°C, 2.0°C, and 3.8°C. Eggs incubated in diel light at 3.9°C developed at the same rate as eggs incubated in constant dark at 3.8°C, but required an additional 72 h to reach 50% hatch. A piece-wise regression model was generated to predict egg age for incubation temperatures of −0.6°C to 3.8°C. For temperatures recorded in the southeastern Bering Sea 1995–1998, the model predicted incubation periods for walleye pollock eggs that varied by 13 days between the warmest and coldest years.Walleye pollock eggs from Shelikof Strait, Alaska, were incubated at 0.2°C, 1.8°C, and 2.8°C. Development was normal for all temperatures. A piece-wise regression model (as above) was generated for incubation temperatures 0.2–2.8°C. When the regression models were compared, Bering Sea eggs (1.4–1.7 mm in diameter), required more time for development prior to hatch than Shelikof Strait eggs (1.2–1.3 mm in diameter) at 1.8°C and 2.8°C. However, for temperatures 0.2–2.0°C, Bering Sea walleye pollock began hatching earlier and at a developmentally younger age than Shelikof Strait walleye pollock.  相似文献   

11.
This study quantifies uncertainties in closing the seasonal cycle of diabatic heat storage (DHS) over the Pacific Ocean from 20°S to 60°N through the synthesis of World Ocean Circulation Experiment (WOCE) reanalysis products from 1993 to 1999. These products are DHS from Scripps Institution of Oceanography (SIO); near-surface geostrophic and Ekman currents from Earth and Space Research (ESR); and air-sea heat fluxes from Comprehensive Ocean-Atmosphere Data Set (COADS), National Centers for Environmental Prediction (NCEP), and European Center for Mid-Range Weather Forecasts (ECMWF). With these products, we compute residual heat budget components by differencing long-term monthly means from the long-term annual mean. This allows the seasonal cycle of the DHS tendency to be modeled. Everywhere latent heat flux residuals dominate sensible heat flux residuals, shortwave heat flux residuals dominate longwave heat flux residuals, and residual Ekman heat advection dominates residual geostrophic heat advection, with residual dissipation significant only in the Kuroshio-Oyashio current extension. The root-mean-square (RMS) of the differences between observed and model residual DHS tendencies (averaged over 10° latitude-by-20° longitude boxes) is <20 W m−2 in the interior ocean and <100 W m−2 in the Kuroshio-Oyashio current extension. This reveals that the residual DHS tendency is driven everywhere by some mix of residual latent heat flux, shortwave heat flux, and Ekman heat advection. Suppressing bias errors in residual air-sea turbulent heat fluxes and Ekman heat advection through minimization of the RMS differences reduces the latter to <10 W m−2 over the interior ocean and <25 W m−2 in the Kuroshio-Oyashio current extension. This reveals air-sea temperature and specific humidity differences from in situ surface marine weather observations to be a principal source of bias error, overestimated over most of ocean but underestimated near the Intertropical Convergence Zone.  相似文献   

12.
Flux of siliceous plankton and taxonomic composition of diatom and silicoflagellate assemblages were determined from sediment trap samples collected in coastal upwelling-influenced waters off northern Chile (30°S, CH site) under “normal” or non-El Niño (1993–94) and El Niño conditions (1997–98). In addition, concentration of biogenic opal and siliceous plankton, and diatom and silicoflagellate assemblages preserved in surface sediments are provided for a wide area between 27° and 43°S off Chile. Regardless of the year, winter upwelling determines the maximum production pattern of siliceous microorganisms, with diatoms numerically dominating the biogenic opal flux. During the El Niño year the export is markedly lower: on an annual basis, total mass flux diminished by 60%, and diatom and silicoflagellate export by 75%. Major components of the diatom flora maintain much of their regular seasonal cycle of flux maxima and minima during both sampling periods. Neritic resting spores (RS) of Chaetoceros dominate the diatom flux, mirroring the influence of coastal-upwelled waters at the CH trap site. Occurrence of pelagic diatoms species Fragilariopsis doliolus, members of the Rhizosoleniaceae, Azpeitia spp. and Nitzschia interruptestriata, secondary components of the assemblage, reflects the intermingling of warmer waters of the Subtropical Gyre. Dictyocha messanensis dominates the silicoflagellate association almost year-around, but Distephanus pulchra delivers ca. 60% of its annual production in less than three weeks during the winter peak. The siliceous thanatocoenosis is largely dominated by diatoms, whose assemblage shows significant qualitative and quantitative variations from north to south. Between 27° and 35°S, the dominance of RS Chaetoceros, Thalassionema nitzschioides var. nitzschioides and Skeletonema costatum reflects strong export production associated with occurrence of coastal upwelling. Both highest biogenic opal content and diatom concentration at 35° and 41°–43°S coincide with highest pigment concentrations along the Chilean coast. Predominance of the diatom species Thalassiosira pacifica and T. poro-irregulata, and higher relative contribution of the silicoflagellate Distephanus speculum at 41°–43°S suggest the influence of more nutrient-rich waters and low sea surface temperatures, probably associated with the Antarctic Circumpolar Water.  相似文献   

13.
Fish living in contaminated environments may exhibit reduced growth which may be due, in part, to the impact of toxicants on prey capture ability. We studied the effects of methylmercury (meHg) and mercuric chloride (Hg) on feeding of Fundulus heteroclitus from Piles Creek, a polluted habitat in Linden, New Jersey. We found that exposure to 0·01 mg/liter of meHg for one week had less impact on the prey capture rate than exposure to a similar concentration of Hg. Exposure to 0·01 mg/liter for two weeks or to 0·02 mg/liter for one week, of either meHg or Hg, produced significant reductions in feeding rate, compared to controls. In general, the fish were affected to a greater degree by exposure to Hg than to meHg. This is the reverse of the usual order of toxicity, but is in keeping with previous observations on this population, in which we have noted that gametes and embryos had developed tolerance to meHg, but were more susceptible to Hg.  相似文献   

14.
Henry's law constants were determined for α- and γ-hexachlorocyclohexane (HCH) as a function of temperature (0.5–45°C) in artificial seawater (SW; 30‰) and distilled water (DW) using the gas stripping method. Water samples (1–5 ml) were withdrawn from the stripping vessel during the stripping process (30–360 h), solvent extracted and analyzed by gas chromatography—electron-capture detection. The effect of bubbling depth was checked to ensure that bubbles leaving the system were at equilibrium with HCHs in the aqueous phase. Henry's law constants determined at 35 and 45°C in SW were significantly higher (P≤ 0.05) than in DW for both α- and γ-HCH, but not at lower temperatures. The slopes (m) and intercepts (b) of log H vs. 1 / T plots were: α-HCH (DW, 0.5–45°C); m = −2810 ± 110, B = 9.31 ± 0.38; α-HCH (SW, 0.5–23°C); M = −2969 ± 218, B = 9.88 ± 0.76; γ-HCH (DW, 0.5–45°C); M = −2382 ± 160, B = 7.54 ± 0.54; γ-HCH (SW, 0.5–23°C); M = −2703 ± 276, B = 8.68 ± 0.96. Henry's law constants determined in this study compared well with those calculated from reported vapor pressure and solubility data.  相似文献   

15.
A modified membrane filter (MF) technique for recovery of faecal coliform bacteria, employing a pre-incubation temperature of 35°C for five hours followed by 18 ± 1 h at 44·5°C was evaluated against the standard MF technique and the multiple-tube (or (most-probable-number (MPN)) procedure in estuarine and marine environments. It was demonstrated that while both MF and MPN procedures supplied substantially the same information, only 75% of the samples analysed with the standard MF procedure fell within the 95% confidence limits of the MPN. When the modified MF was used, 90% of the counts fell within the confidence limits. On average, the modified MF yielded 50% higher counts than did the standard MF method.  相似文献   

16.
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17.
Midsummer (1 August) population estimates of about 2 million O-group plaice (Pleuronectes platessa L.) were derived for sandy bays around the Firth of Forth in 1979–1980. This is an order of magnitude less than similar estimates made for the Clyde Sea Area in 1973–1974. Autumn population estimates of 0·4–1·0 million fish were comparable to estimates by the Ministry of Agriculture, Fisheries and Food for the area between the Scottish border and Flamborough Head (2·3 million for 1970 and 1973) which represented 4·8% (1973) to 5·3% (1970) of the total number of O-group fish on the English east coast.Largo Bay was the most important nursery area holding 25% of the total population. It is particularly well situated to receive newly metamorphosed plaice carried in water currents along the north side of the Forth from the spawning ground off Fife Ness. Plaice in the Forth are mainly distributed on fine to medium sandy beaches (186–480 μm), the mean number per haul in midsummer (D) being correlated with the median diameter (m.d. in μm) of the low water sediments by the equation: D=−45·7666+0·2327 m.d. (n=11,r=0·68,P<0·02 but>0·01).The shallow inshore water in sandy bays in the outer Firth was well mixed and more marine than estuarine (27·7–35·0‰). The correlation coefficient between fish density and water temperature was low, while that with salinity (S‰) was: D=6·1618+0·2238S (n=23,r=0·62,P<0·005).Regression analysis demonstrated that the relationship between the instantaneous mortality rate (Z) and the initial population density (Dp) was: Z×100=0·7480+0·0546dp (n=12,r=0·87,P<0·001).The mean mortality rate for the O-group plaice in the Forth nursery areas was 53% month−1.  相似文献   

18.
The effect of dissolved petroleum hydrocarbons in the environment on phytoplankton biomass measured as chlorophyll a was studied near the oil tanker route in the southern Bay of Bengal. In the transect from 5° N, 77° E to 5° N, 87° E the concentrations of dissolved petroleum hydrocarbons were negatively correlated with phytoplankton biomass, whereas in the 0° N, 87° E to 1° N, 79° E transect they were positively correlated with phytoplankton biomass. The mean petroleum hydrocarbon concentrations in the two transects were 12·12 ± 4·67 μg litre−1 and 11·23 ± 4·5 μg litre−1, respectively.It is surmised that the effect of dissolved petroleum hydrocarbons on phytoplankton biomass varies depending on the nature rather than the quantity of petroleum hydrocarbons present. Culture studies with unialgal Nitzschia sp. in seawater collected from selected stations in the study area as well as in artificial seawater spiked with the water-soluble petroleum hydrocarbon fraction of light Arabian Crude support this.  相似文献   

19.
The effects of zinc being added to sea water, to final concentrations of 0·1–20 ppm, have been studied on the heart rate, valve movements, mortality of Scrobicularia and on both isolated and in situ inhalant siphon preparations.The acute toxicity threshold for added zinc was determined to be about 10 ppm at 10°C. The median lethal times for 10 and 20 ppm zinc were 143·5 and 116·1 h respectively.The responses of Scrobicularia to zinc concentrations in sea water of between 0·1 and 10 ppm were tested by exposure for 6 h. Above 1 ppm, valve closure and bradycardia occur within 10–15 min. Below 5 ppm the valves subsequently opened and heart rate increased over the 6 h period, but in 10 ppm closure and pronounced bradycardia were maintained throughout.Addition of zinc, to final concentrations of 1, 5 and 10 ppm, had no effect on the isolated inhalant siphon in contrast to copper at 0·25 and 0·5 ppm which caused very marked siphonal contractions. However, when zinc (1–10 ppm) was added to an in situ inhalant siphon preparation, contractions occurred which were lost on removal of zinc from the bathing medium. Cutting the cruciform muscles medially resulted in the loss or delay of the response to zinc. This suggests the possibility of the cruciform muscle complex (muscle strands and associated sense organs) responding to zinc. This contrasts with the direct action of copper on the neuromuscular system of an isolated siphon.  相似文献   

20.
Sediment samples were collected at stations along cross-shelf transects in Onslow Bay, North Carolina, during two cruises in 1984 and 1985. Station depths ranged from 11 to 285 m. Sediment chlorophyll a concentrations ranged from 0·06 to 1·87 μg g−1 sediment (mean, 0·55), or 2·6–62·0 mg m2. Areal sediment chlorophyll a exceeded water column chlorophyll a a at 16 of 17 stations, especially at inshore and mid-shelf stations. Sediment ATP concentrations ranged from 0 to 0·67 μg g−1 sediment (mean, 0·28). Values for both biomass indicators were lowest in the depth range including the shelf break (50–99 m). Organic carbon contents of the sediments were uniformly low across the shelf, averaging 0·159% by weight. Photography of the sediments revealed extensive patches of microalgae on the sediment surface.Our data suggest that viable benthic microalgae occur across the North Carolina continental shelf. The distribution of benthic macroflora on the North Carolina shelf indicates that sufficient light and nutrients are available to support primary production out to the shelf break. Frequent storm-induced perturbations do not favour settling of phytoplankton, an alternative explanation for the presence of microalgal pigments in the sediments. Therefore, we propose that a distinct, productive benthic microflora exists across the North Carolina continental shelf.  相似文献   

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