共查询到20条相似文献，搜索用时 31 毫秒
1.
By using the relationships between the measurement error of hydrostatic CTD sea-level meters, the errors of measuring channels of hydrostatic pressure, temperature, and conductivity, and the errors
of determination of the gravitational acceleration, we estimate the admissible measurement errors for separate channels. Simplified
relations for the evaluation of salinity and density of water corresponding to the class of accuracy of the level meter are
presented. Possible differences between the readings of the level meters mounted at coastal level-measuring posts and the
actual sea level in the coastal zone caused by the weak water exchange in the sea-well system are estimated.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 62–76, January–February, 2006. 相似文献
2.
中国东海和南黄海沿海平原MIS 3晚期海侵层的动力模拟研究 总被引：1，自引：0，他引：1
Abundant evidences of higher sea levels from Jiangsu and Fujian coasts have proved a marine transgression event during 30–40 ka BP, suggesting that there was a stage with high sea level and a warm climate when ice sheets shrank in the Northern Hemisphere. The duration of 30–40 ka BP spanned a period in the late Marine Isotope Stage 3(MIS 3) and was in nature an interstadial epoch during the Last Glacial period of the Quaternary. Different from the glacial period with a cold climate, this marine transgression considered as a penultimate higher sea level during the Quaternary remains a puzzle that why the evidence is contrary to the Quaternary glacial theory. It is important to understand sea level rise for these areas sensitively responding to the global changes in the future. To recognize the key issues on sea level changes, the eustatic sea level(H_S) was defined as the glaciation-climateforced sea levels, and the relative sea level change(H_R) was defined as that a sea level record was preserved in sediment that experienced multiple secondary actions of land and sea effects. On the basis as defined above, we constructed multi-level models of climate-driven glacio-eustatic changes and land-sea systems. By integrating data sets from eight borehole cores and prescribing the boundary conditions, we simulated the changes of HS and HR in the East China Sea and southern Yellow Sea areas in the late MIS 3. The marine transgression strata from the borehole core data was identified at ca. 30 m below present sea level as a result of the collective influence of ice melting water, neotectonic subsidence, sediment compaction and terrestrial sediment filling since ca. 35 ka ago,whereas the simulated relative sea-levels turned out to be –26.3––29.9 m a.s.l. The small error involved in the simulation results of ±(2.5–4.5) m demonstrated the credibility of the results. Our results indicated that sea level change in the late MIS 3 was dominated by glacial effects, in which the eustatic sea-level was between –19.2––22.1m a.s.l. The study sheds light on the nature of sea-level changes along the east coast of China in the late MIS 3 and contributes to understanding the characteristics of marine transgression under the effects of multiple complex land-sea interactions. 相似文献
3.
Pisces submersible dives within Baffin Island fjords have revealed the common occurrence of pits on the sea floor, at water depths
between 40 and 326 m. The size of these pits are in the decimeter to meter range. Through indirect evidence (by comparison
of morphologic features to pits or gouges of known origin) they are believed to be feeding traces of narwhal, beluga, or bowhead
whales. If so, they are the deepest mammalian feeding traces yet reported. Bioerosion by large foraging mammals may be a more
common sea floor process than previously thought. 相似文献
4.
On the basis of the analyses of significant periods for the sea level observation data taken from recent several decades at 12 tide stations, the monthly mean sea level observations are fitted by a model of linear trend of sea level change superimposed with several variations of different fixed periods. The trends of sea level relative changes and their errors are estimated by the LS method. The results are reduced to the isostatic datum proposed and established in the paper (Huang et al. , 1991, Seismology and Geology , 1, 1-15). The trends of sea level changes in the near future along the coast of China are studied. It is pointed out that the general trend of the sea level change along the coast of China is going up slowly and the rate of the change is not the same in different segments of the coasts. In a few segments, the sea level is even relatively going down. The numerical results given in this paper provide a basis for the predictions of the future sea level changes and their effects. 相似文献
5.
J. L. McKoy 《新西兰海洋与淡水研究杂志》2013,47(4):403-409
In Tauranga Harbour, Lyrodus medilobatus was found in greatest numbers on test‐blocks placed near the bottom, while Bankia australis, B. neztalia, and Nototeredo edax had a more uniform vertical distribution. Shipworms occurred in the intertidal zone up to about mean sea level. In Wellington Harbour, B. neztalia was found in test‐blocks up to mean sea level, but was most abundant in blocks near the bottom. In the Bay of Islands, shipworms settled in the intertidal on test‐blocks as high as 30 cm below mean sea level. B. australis was the most abundant species in mangrove wood in northern New Zealand, and L. medilobatus occurred occasionally. No evidence was found for shipworms settling on living mangrove wood, although they frequently tunnelled from dead wood into living wood. 相似文献
6.
贻贝养殖,在我国沿海地区已经广泛开展。贻贝人工育苗是解决贻贝养殖苗种的途径之一,尤其在自然苗缺乏的地区,或是为了选择优良品种出发,更有其重要意义。我们在过去工作的基础上,于1972—1974年期间,在胶南县海水养殖场进行了贻贝生产性人工育苗试验。以后又在青岛进行了一些培养条件的研究。通过几年的工作,对于育苗的一些重要环节,尤其对于提高室内水池培养到附着阶段的成活率,和探索下海后掉苗的原因,已取得了一定的成果,使人工育苗生产初具规模。现将主要结果报告于下。 相似文献
7.
Christopher T. Mills Robert F. Dias Dennis Graham Kevin W. Mandernack 《Marine Chemistry》2006,98(2-4):197-209
Sediment samples ranging from 0.05 to 278 m below sea floor (mbsf) at a Northwest Pacific deep-water (5564 mbsl) site (ODP Leg 191, Site 1179) were analyzed for phospholipid fatty acids (PLFAs). Total PLFA concentrations decreased by a factor of three over the first meter of sediment and then decreased at a slower rate to approximately 30 mbsf. The sharp decrease over the first meter corresponds to the depth of nitrate and Mn(IV) reduction as indicated by pore water chemistry. PLFA-based cell numbers at site 1179 had a similar depth profile as that for Acridine orange direct cell counts previously made on ODP site 1149 sediments which have a similar water depth and lithology. The mole percentage of straight chain saturated PLFAs increases with depth, with a large shift between the 0.95 and 3.95 mbsf samples. PLFA stable carbon isotope ratios were determined for sediments from 0.05 to 4.53 mbsf and showed a general trend toward more depleted δ13C values with depth. Both of these observations may indicate a shift in the bacterial community with depth across the different redox zones inferred from pore water chemistry data. The PLFA 10me16:0, which has been attributed to the bacterial genera Desulfobacter in many marine sediments, showed the greatest isotopic depletion, decreasing from − 20 to − 35‰ over the first meter of sediment. Pore water chemistry suggested that sulfate reduction was absent or minimal over this same sediment interval. However, 10me16:0 has been shown to be produced by recently discovered anaerobic ammonium oxidizing (anammox) bacteria which are known chemoautotrophs. The increasing depletion in δ13C of 10me16:0 with the unusually lower concentration of ammonium and linear decrease of nitrate concentration is consistent with a scenario of anammox bacteria mediating the oxidation of ammonium via nitrite, an intermediate of nitrate reduction. 相似文献
8.
The sandy beaches of Anapa Bay Bar are a unique natural resource, but they are gradually being degrade under both natural
and anthropogenic factors. The emissions of sand and shelly ground from the adjacent sea bottom partly compensate for this
process. The concentration of carbonates may reach up to 50% in the beach sands, and most of these carbonates are of mollusk
origin. The major deposit formation role belongs to the key bivalve species: Chamelea gallina (Linnaeus, 1758). The average biomass of this mollusk species reaches up to 450 g/m2 at the depths of 5–10 m. The other two subdominating mollusk species, the bivalve Donax trunculus (Linnaeus, 1758) and the gastropod Rapana venosa (Valenciennes, 1846), may impact as 16 g/m2 and 6 g/m2, respectively. Annually, 350 kg of shelly ground per running meter are newly deposited on Anapa beach. 相似文献
9.
Tide gauges distributed all over the world provide valuable information for monitoring mean sea level changes. The statistical models used in estimating sea level change from the tide gauge data assume implicitly that the random model components are stationary in variance. We show that for a large number of global tide gauge data this is not the case for the seasonal part using a variate-differencing algorithm. This finding is important for assessing the reliability of the present estimates of mean sea level changes because nonstationarity of the data may have marked impact on the sea level rate estimates, especially, for the data from short records. 相似文献
10.
Stefano Schiaparelli Giancarlo Albertelli & Riccardo Cattaneo-Vietti 《Marine Ecology》2006,27(1):44-53
Some organisms represent useful Biological Sea‐Level Indicators (Bio SLI) thanks to their constant position relative to sea level and allow the reconstruction of past sea level changes. The sessile gastropods Vermetidae are among the most used indicators, since their shells often resist time averaging and can be easily dated with 14C. However, all these vermetids have a level of precision (± 0.5–1 m), obtained from data on the Mediterranean Dendropoma petraeum (Monterosato, 1884). We found a certain degree of plasticity in this species; it can also live subtidally, not in correspondence with the main sea level, where it feeds adopting a mixed feeding strategy. Considering this variability and the almost complete lack of knowledge for other Bio SLI vermetids, it appears clear that a common value of precision cannot be maintained and the precision of other vermetid species remains to be tested. 相似文献
11.
A wave-height meter using a simple microwave Doppler radar,simeq10 mW in power and 10.525 GHz in frequency, is proposed so that we can measure oceanic waves effectively while the ship is steaming. It was first applied to the measurement of the variation of water level generated in a wave tank, which suggested that it is adequately applicable to the measurement of oceanic waves. A field test was carried out off the cape of Nojimazaki by installing the Doppler radar 5 m above the sea level at the bow of the ship. The result agreed reasonably well with that measured simultaneously by the ultrasonic wave-height meter installed at the same position. Another test is running successfully on a larger ship with the wave-height meter installed at 9 m above the sea level. The significant wave height measured by the present meter is being compared with that observed visually by the navigation officers. 相似文献
12.
东北大西洋海洋捕捞渔获物营养级变化研究 总被引：5，自引：3，他引：2
东北大西洋是重要的海洋捕捞海域,该海域渔业栖息环境易受北极气候变化的影响。为此,本文基于1950-2012年东北大西洋FAO的渔获统计数据,对已开发的293种渔获物平均营养级(mTL)、营养级平衡指标(FIB)和渔获营养级分类(TrC)进行时间序列的统计,为进一步研究该海域渔业资源受北极气候变化的影响提供基础。研究认为,平均营养级(mTL)从1950年(mTL=3.71)下降至2012年(mTL=3.57),每年下降约0.02TL(r=-0.614;P<0.01),而近8年来营养级平衡指数持续下降。同时,研究表明,东北大西洋渔获物平均营养级和气候变化(海表温上升、北大西洋涛动和海冰缩减等)息息相关,其中渔获量出现高产值均在海表温异常年份:1956年、1976年和1997年。本文分析了东北大西洋渔获物营养级变动情况,为研究东北大西洋渔获组成变化与气候变化的关系提供研究基础,也为渔业资源的可持续开发提供了理论依据。 相似文献
13.
Mingfang Yang Yushi Yu Jingyun Ding Jia Luo Jiangnan Sun Fangyuan Hu Yaqing Chang Chong Zhao 《Marine Ecology》2020,41(4):e12593
The detection of light intensity and subsequent phototaxis are essential for the fitness of sea urchins in intertidal and shallow subtidal waters, where light intensity varies in accordance with the depth and other hydrographic conditions. The molecular basis of photoresponse, however, remains largely unknown. We compared the expression of SiOpsin4, SiPax6, and SiOpsin5 among tube feet, coelomocytes, gonads, and gut of the sea urchin Strongylocentrotus intermedius. All three genes showed the significantly highest expression in tube feet. To test whether r-opsin genes (for example, Opsin4) and Pax6 in tube feet, rather than chaopsin genes (for example, Opsin5), are involved in the molecular responses to light intensity, we investigated the expression of Opsin4, Pax6, and Opsin5 among four light intensities. Both Opsin4 and Pax6 expressions were significantly higher in the sea urchins at 1,500 lx than at 100, 300, and 700 lx, indicating a co-upregulation of Opsin4 and Pax6 expressions in sea urchins exposed to the high light intensity (for example, 1,500 lx). However, there was no significant difference of SiOpsin5 expression among the four light intensity groups. Consistent with our hypothesis, there was no significant difference in either Opsin4 or Pax6 expression between the two light intensity environments (low light intensity environment: 50–100 lx; high light intensity environment: 330–1400 lx). This indicates that positive phototaxis and negative phototaxis probably regulate the expression of Opsin4 and Pax6 to a similar level when sea urchins are exposed to the high and low light intensities, respectively. The present study provides new insights into the molecular basis of light intensity detection and subsequent phototaxis of eyeless species. 相似文献
14.
以大、中、小3种不同规格的刺参(Apostichopus japonicus)为对象,在pH为7.3、7.5、8.2、8.7、8.9不同环境中养殖30d,观测刺参行为、生长及溶菌酶(LZM)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性。结果显示:当pH为7.5、8.7时, 3种不同规格刺参均能正常活动、摄食、生长,未表现出异常状况;若超出此范围,刺参出现粪便细短、残饵增多、摄食量减少等现象,尤其在pH 8.9时,中规格刺参有明显棘刺收缩的现象,小规格刺参不同程度地出现身体收缩、棘刺平滑状态,而大规格刺参无明显表观不适现象。不同pH对3种规格刺参的特定生长率(SGR)有显著影响,随着pH升高或者降低,刺参SGR均逐渐下降,与对照组差异显著(P0.05),规格越小刺参受到抑制作用越大;刺参LZM、SOD、CAT活性随pH胁迫时间的延长呈现先升高后下降的趋势,在第10天时达到最高,与对照组差异显著(P0.05),至30 d胁迫结束时,在pH 7.3、8.9条件下,刺参免疫酶活性显著低于对照组(P0.05),而pH为7.5、8.7时,刺参免疫酶活性与对照差异不显著; pH胁迫对不同规格刺参非特异性免疫酶活性的影响存在差异,在相同胁迫条件下,酶活性依次为大规格中规格小规格,当pH7.3、8.9时,小中大规格分别在胁迫20 d、25 d、25 d后免疫酶活性显著低于对照组(P0.05)。研究表明, pH胁迫会对刺参生长及免疫产生明显的影响,在刺参养殖过程中, pH属关键的理化因子之一,应密切关注其变化。 相似文献
15.
A three-dimensional, nonlinear, primitive equation ocean general circulation model is used to study the response of the Gulf of Mexico to Hurricane Frederic. The model has free surface dynamics and a second order turbulence closure scheme for the mixed layer. Realistic coastlines, bottom topography and open boundary conditions are used in the study. The model has a vertical sigma coordinate with 18 levels, and a horizontal resolution of 0.2°×0.2° for the entire Gulf. The study focuses on hurricane generated sea level, current, and coastally trapped wave (CTW) responses of the Gulf. Time series of sea levels from U.S. coastal tide gauge stations and the numerical model simulation of sea levels and currents on the shelf are used to study sea level, current and CTW responses. Both model sea levels and observations from tide gauge stations show a westward progression of the surge as a CTW response. The results of the study of sea levels and currents indicate that CTW propagate to the west with phase speeds of 7–10 m s–1. There is also a strong nonlinear interaction between the Loop Current and hurricane induced currents. The surface current attains a maximum of 200 cm s–1 in the eastern Gulf. The model surface elevation at several locations is compared with tide gauge data. The current meter data at three moorings are also compared with the model currents. The model simulations show good agreement with observed data for the hurricane induced coastally trapped wave, storm surge, and current distribution in the Gulf. 相似文献
16.
Sea-level observations made during December, 1979, at six stations in Great South Bay (which is a coastal lagoon on the south shore of Long Island, New York) reveal that there were significant subtidal fluctuations in addition to the tidal oscillations. Harmonic analysis of the tidal oscillations of sea level indicates that M2 is the dominant tidal constituent. The M2 amplitude, however, suffered a more than 50% reduction in the interior of the Bay due largely to the narrow inlet. The subtidal sea level fluctuations within the Bay were forced primarily by the low-frequency fluctuations of the adjacent shelf water. The active subtidal exchange induced by this Bay-shelf coupling appeared to have suffered only minor attenuation within the Bay. As a consequence, the variance associated with subtidal sea level fluctuations was greater than that associated with the tidal oscillations over most of Great South Bay. 相似文献
17.
根据2021年渔业资源调查数据构建了含有23个功能组的舟山海域生态系统Ecopath模型,分析了当前舟山海域生态系统总体特征并估算了褐菖鲉在舟山海域的生态容量。结果表明:舟山海域生态系统营养级范围为1.000 (浮游植物和有机碎屑)～4.277 ( 鳐类),石首鱼科、虾类和 鳐类为舟山海域生态系统中的关键种。碎屑食物链和牧食食物链是舟山海域生态系统主要的食物链。碎屑和浮游植物对食物网的贡献率分别为61.32%和38.69%。始于浮游植物和碎屑的营养传递效率分别是9.34%和10.50%,系统总营养传递效率是9.82%。总初级生产量/总呼吸量为2.26,系统连接指数为0.372,系统杂食性指数为0.222。生态系统总体特征反映了舟山海域生态系统的成熟状态较低,生态系统处于不稳定阶段,容易受到外界环境变化的影响。根据模型估算,当褐菖鲉生物量增加至8.6倍时,褐菖鲉达到生态容量0.007 95 t/km2,此时生态系统仍保持平衡,且生态系统总体特征基本稳定。因此,褐菖鲉在舟山海域尚有较大增殖潜力。 相似文献
18.
Jin Yaqiu 《海洋学报(英文版)》1998,(1):53-61
ＭｏｎｉｔｏｒｉｎｇｒｅｇｉｏｎａｌｓｅａｉｃｅｏｆｔｈｅＢｏｈａｉＳｅａｂｙＳＳＭ／ＩｓｃａｔｔｅｒｉｎｇｉｎｄｅｘＪｉｎＹａｑｉｕ（ＲｅｃｅｉｖｅｄＪａｎｕａｒｙ６,１９９７;ａｃｃｅｐｔｅｄＭａｒｃｈ３０,１９９７）Ａｂｓｔｒａｃｔ──ＳＳＭ／... 相似文献
19.
An Antarctic sea ice identification algorithm on the HY-2A scatterometer(HSCAT) employs backscattering coefficient(σ0) and active polarization ratio(APR) for a preliminary sea ice identification.Then standard deviation(STD) filtering and space filtering are carried out.Finally,it is used to identify sea ice.A process uses a σ0,STD threshold and an APR as sea ice indicators.The sea ice identification results are verified using the sea ice distribution data of the ASMR2 released by the National Snow and Ice Data Center as a reference.The results show very good consistence of sea ice development trends,seasonal changes,area distribution,and sea ice edge distribution of the sea ice identification results obtained by this algorithm relative to the ASMR2 sea ice results.The accuracy of a sea ice coverage is 90.8% versus the ASMR2 sea ice results.This indicates that this algorithm is reliable. 相似文献
20.
A bottom pressure gauge (BPG) was installed in proximity (3.7 km at closest approach) of Jason-1 and formerly TOPEX/Poseidon (T/P) ground track No. 238 at the Wusi site, located ～ 10 km offshore off the west coast of Santo Island, Vanuatu, Southwest (SW) Pacific. Sea level variations are inferred from the bottom pressure, seawater temperature, and salinity, corrected for the measured surface atmospheric pressure. The expansion of the water column (steric increase in sea surface height, SSH) due to temperature and salinity changes is approximated by the equation of state. We compare time series of SSH derived from T/P Side B altimeter Geophysical Data Records (GDR) and Jason-1 Interim Geophysical Data Records (IGDR), with the gauge-inferred sea level variations. Since altimeter SSH is a geocentric measurement, whereas the gauge-inferred observation is a relative sea level measurement, SSH comparison is conducted with the means of both series removed in this study. In addition, high-rate (1-Hz) bottom pressure implied wave heights (H 1/3 ) are compared with the significant wave height (SWH) measured by Jason-1. Noticeable discrepancy is found in this comparison for high waves, however the differences do not contribute significantly to the difference in sea level variations observed between the altimeter and the pressure gauge. In situ atmospheric pressure measurements are also used to verify the inverse barometer (IB) and the dry troposphere corrections (DTC) used in the Jason IGDR. We observe a bias between the IGDR corrections and those derived from the local sensors. Standard deviations of the sea level differences between T/P and BPG is 52 mm and is 48 mm between Jason and BPG, indicating that both altimeters have similar performance at the Wusi site and that it is feasible to conduct long-term monitoring of altimetry at such a site. 相似文献