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1.
Bruno Cataletto Enrico Feoli Serena Fonda Umani Marina Monti Irene Pecchiar 《Marine Ecology》1996,17(1-3):291-307
Abstract. Multivariate techniques (cluster analysis and Principal Component Analysis) applied on phytoplankton data collected in June, July, August, and September 1990, 1991, 1992, and 1993 in the Gulf of Trieste (Northern Adriatic Sea) highlighted a clear temporal pattern from 1990 to 1993. In the summer of 1991, phytoplankton communities showed a dramatic increase in the dinoflagellatddiatom ratio. In particular, during June and July 1991 only few specimens of diatoms ( Cylindrorhecu closreriurn. Probosciu alata, Nirzschio longissimu , and Nitzschiu spp.) were collected; this confirmed the diatom scarcity in the phytoplankton communities before and during the appearance of large mucous aggregates (mucilage) in July 1991 in the Gulf of Trieste. The differences observed between the structure of the phytoplankton communities inside the aggregates and in the ambient waters suggested two hypotheses: 1) the aggregates were not produced in the gulf, but were carried ints the gulf by the eastern bordering current; 2) the aggregates were produced by a few, scarce species with a high exudate production that are capable of quickly reaching a high reproductive rate within the aggregates. 相似文献
2.
1998年春夏南海温盐结构及其变化特征 总被引：11，自引：2，他引：11
利用1998年5～8月“南海季风试验”期间“科学1”号和“实验3”号科学考察船两个航次CTD资料,分析了1998年南海夏季风暴发前后南海主要断面的温盐结构及其变化特征.观测发现,南海腹地基本被典型的南海水团所控制,但在南海东北部尤其是吕宋海峡附近,表层和次表层水明显受到西太平洋水的影响.季风暴发以后,南海北部表面温度有显著升高,升幅由西向东递减,而南海中部和南部表面温度基本没变,这使得南海北部东西向温度梯度和整个海盆南北向温度梯度均减小.北部断面表层盐度普遍由34以上降低到34以下,混合层均有所发展,是季风暴发后降水和风力加剧的结果.观测期间黑潮水跨越吕宋海峡的迹象明显但变化剧烈.4～5月,黑潮次表层水除在吕宋海峡中北部出现外,在吕宋岛以西亦有发现,表明有部分黑潮水从吕宋海峡南端沿岸向西进而向南进入南海.6～7月,次表层高盐核在吕宋海峡中北部有极大发展,但在吕宋岛以西却明显萎缩;虽然看上去黑潮水以更强的流速进、出南海,但对南海腹地动力热力结构的影响未必更大.一个超过34.55的表层高盐水体于巴拉望附近被发现,似与通过巴拉望两侧水道入侵南海的西太平洋水有关. 相似文献
3.
Abstract. Vertical profiles of temperature, nutrients (silicate, phosphate, and nitrate), chlorophyll a and phytoplankton abundance are given for six stations located in the Gulf of California, June 1982, above 1 % of light intensity. The vertical distribution of phytoplankton was related to the water column structure: stratified stations had a defined nutricline and subsurface chlorophyll and phytoplankton abundance maxima were present, which were found to be related to the depth of the principal thermocline; vertical distribution of taxa was not uniform and low affinity values (< 0.5) were calculated among depths at these stations. Despite the irregular vertical distribution of chlorophyll and cell number, there was a great affinity in the species composition throughout the euphotic zone at well-mixed or weakly stratified stations. Nanoplankton organisms, mainly coc-colithophorids, were the most important numerical contributors at the chlorophyll maxima, except when this was superficial, in which case diatoms were the most numerous group. Some patterns of the vertical distribution of the main phytoplankton groups ( e.g. , diatoms, dinoflagellates, and microflagellates) are shown. The spectrum of diversity in the water column was useful only for mixed-waters. The relationship between stability, nutrients, and phytoplankton - regarding their vertical distribution - and the importance of physical and biological processes on phytoplankton ecology are discussed. 相似文献
4.
C. G. Castro C. A. Collins P. Walz J. T. Pennington R. P. Michisaki G. Friederich F. P. Chavez 《Progress in Oceanography》2002,54(1-4)
Nutrient conditions off central California during the 1997–98 El Niño are described. Data were collected on 11 cruises from March 1997 to January 1999 along a hydrographic section off central California, as well as every two weeks at a coastal station in Monterey Bay. Perturbations associated with El Niño are shown as anomalies of thermohaline and nutrient distributions along this section. The anomalies were obtained by subtracting seasonal averages for the period from April 1988 to April 1991 from the 1997–98 observations. The first indications of El Niño conditions (high sea levels) were observed at Monterey between late May and early June 1997, but the coastal nutricline did not begin to deepen until August 1997. It reached maximum depth of 130 dbar in January 1998 at the time that maximum sea level anomalies were observed. During this period: (1) the highest subsurface temperature anomalies coincided with subsurface nutrient anomaly minima at the depth of the pycnocline; (2) southern saline and nutrient-poor waters occupied the upper 80 dbar of the water column along the entire section; and (3) nitrate levels were close to zero in the euphotic zone, collapsing the potential new primary production in the coastal domain. At the end of February 1998, the nutricline shoaled to 40 dbar at the coast although it remained anomalously deep offshore. Higher temperatures and lower nutrient levels were observed for the entire section through August 1998 although in contrast with the previous winter, there was a strong freshening mainly due to an onshore movement of subarctic waters. 相似文献
5.
Larry P. Atkinson Thomas N. Lee Jackson O. Blanton Gustav-Adolf Paffenhfer 《Progress in Oceanography》1987,19(3-4)
During the summer of 1981 a large scale sampling effort took place in the shelf waters of the southeastern United States. The goal of this effort was to quantify the effect of the intrusion of deep Gulf Stream water into these shallow, euphotic waters. By making repeated hydrographic measurements over the entire shelf area, the actual volume of the intrusions was determined. Two main intrusion events were observed: one in June and early July and a second in late July and early August. The intruding water entered the shelf in the region south of St Augustine and was transported northward by the mean northward shelf circulation. The subsurface cold water mass was isolated from the Gulf Stream by a ridge of warmer water along the shelf break.The intrusions resulted in increased stability in shelf waters with vertical temperature gradients as high as 10°C m−1. The potential energy in the stratified shelf waters typically ranged from 1000 to 2000 J m−2 that would require 2 to 4 mW m−2 to mix. However, since only 0.1 to 1.0mW m−2 was available from wind and tidal mixing, the water column stayed stratified in most cases.The amount of nitrate transported onto the shelf was determined by two methods: direct observation by synoptic cruises and transport measurements using current meter arrays. Both methods gave similar results with about 18,000 tons nitrogen in the large June/July intrusion. On a seasonal basis, 40,000 tons of nitrogen could be advected into shelf waters which could result in 200,000 to 400,000 tons carbon production. 相似文献
6.
Physical oceanographic data were collected during September 1975 at stations in the shallow water (max. depth 45 m) embayments of Salonica Bay and Thermaicos Gulf, and comparisons are made with data collected during other seasons. The distribution of temperature and salinity in the water column indicated the following features: fresh surface water predominantly related to river discharge; an intermediate water mass, apparently formed by mixing between the fresh and open sea waters; a thermocline, and deep bottom water open sea characteristics. The summer distribution of density in the surface and bottom waters, and the seasonal variation in the pattern of surface salinity, suggested an anti-clockwise water circulation throughout the embayments. 相似文献
7.
深渊观测是开展深渊科学研究的前提。文章介绍了2020年7月"东方红3"船在马里亚纳海沟"挑战者深渊"附近完成的一次海洋调查。基于船载温盐深综合剖面测量系统获取的万米级剖面数据,分析全海深的温盐性质,并依据Thorpe尺度方法和细尺度参数化方法,进一步估算不同深度层的湍动能耗散率。结果表明:"挑战者深渊"的深层海水十分稳定, 3 000—5 000 dbar的温盐特征与下层绕极水相同;受弱层结背景下的内潮影响, 5 000—8 000 m的耗散率显著提升。本次调查获取的万米级水文剖面为马里亚纳海沟的深渊探索提供了数据方面的支撑。 相似文献
8.
9.
Tetsuo Yanagi Suhendar I Sachoemar Toshiyuki Takao Shunji Fujiwara 《Journal of Oceanography》2001,57(4):461-470
Intensive hydrographic observations were carried out in the western part of the Gulf of Thailand and the east coastal sea
of Peninsular Malaysia in September 1995 and April–May 1996. The characteristics of seasonal variation of oceanic condition
in that area are discussed basis of an analysis of observed water temperature, salinity and density distributions in these
cruises and NAGA cruises (Yanagi and Takao, 1998a). Stratification is most developed in March–May mainly due to large sea
surface heating and weak sea surface wind, which weakened until September–October, vanishing in December–January. The horizontal
distribution of bottom cold, saline and heavy water masses, which are found during the stratified season, is governed by the
tidal mixing and the water depth. Water exchange between the Gulf of Thailand and the South China Sea becomes large in March–May
due to a coupled effect of the intensified estuarine circulation and the Ekman transport by the southwest monsoon.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
11.
《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(9):1474-1485
In an attempt to understand the causes of the sea-level seasonal cycle in the Persian Gulf, we investigated the relationships of sea-level data from 11 stations with atmospheric pressure and thermosteric level. Sea level is significantly correlated among all stations. The mean trend in sea level for the Persian Gulf is about 2.34 mm/year. The thermosteric sea-level variability is estimated from temperature profiles at one-degree grid points. Contour maps of thermosteric level show that the height due to thermal expansion is high in summer and autumn, and low during winter and spring. The monthly mean thermostric height ranges from +2.2 cm in July to −2.1 cm in February. The major change in sea level due to the thermosteric level seems to be associated with the large change of the thermohaline circulation in the Persian Gulf. The maximum expansion occurs in summer, and the maximum contraction occurs in winter.Results of the regression analysis demonstrate that from 62% to 90.2% of the variance in the seasonal cycle is due to atmospheric pressure. The inclusion of the thermosteric sea level as a secondary forcing in the regression model improves the variance explained to 78.1–90.7%. The remaining change should be due to the halosteric effect and upwelling. Tide-gauge stations located at the Gulf's head show high correlation with Ekman vertical velocity. There are two distinct tide gauge stations in the Persian Gulf. One is found in the first cyclonic gyre and the other in the second gyre. The inclusion of Ekman upwelling to the model, improves significantly the variations explained as well, from 82.3% to 91.9%. 相似文献
12.
Temporal variability of Centropages typicus in the Mediterranean Sea over seasonal-to-decadal scales
《Progress in Oceanography》2007,72(2-3):214-232
Centropages typicus is one of the most common, abundant and best studied calanoid copepods in neritic waters of the Mediterranean Sea, which means it can provide useful information about the long-term dynamics of the Mediterranean epipelagic ecosystem. This paper presents the first comparative overview of the seasonal and long-term variability of C. typicus in different Mediterranean regions. This review is based on quantitative information from the published literature and novel data from five ongoing zooplankton time-series carried out in the Mallorca Island (Balearic Sea), the Bay of Villefranche (Ligurian Sea), the Gulf of Naples (Tyrrhenian Sea), the Gulf of Trieste (North Adriatic Sea), and the Saronikos Gulf (Aegean Sea). In most Mediterranean regions, C. typicus has a perennial occurrence, with peaks of abundance that reflect the succession of different generations. Throughout the Mediterranean, the annual cycle of C. typicus is characterized by minima in winter and major peaks in April–June, which is earlier than those observed in European Atlantic waters, where the peaks are more frequently recorded in summer and fall. In the regions investigated, the annual cycle shows remarkable similarities in terms of timing, but notable differences in the peak height; populations are far more abundant in coastal north-western regions and less abundant in the eastern basin. In the long-term, changes in C. typicus phenology observed in the Bay of Villefranche and in the Gulf of Naples are related to the North Atlantic Oscillation (NAO) index. In these two regions, the species responds to climate forcing similarly in terms of average seasonal patterns (bi-modal patterns in years of positive NAO, unimodal patterns in years of negative NAO) but oppositely in terms of quantity, indicating different influence of the NAO on the two regions. At decadal scales, C. typicus populations show high interannual variability with marked geographical differences. In some areas, the patterns are clearly characterized by alternate phases of higher and lower annual abundances, at higher frequency (mainly 1–2 years) in the Gulf of Naples, and lower frequency in the Saronikos Gulf (mainly 4–5 years) and in the Gulf of Trieste (mainly 5–6 years). Synchronous phases of increasing or decreasing abundance are discernable only for a few sites and short periods, for example from 1998 to 2000 in the Gulf of Naples, Gulf of Trieste and Saronikos Gulf. The regional differences observed in the long-term patterns of C. typicus populations suggest that the temporal dynamics of this species are significantly more affected by local conditions than by any possible common driving force acting at basin scale through teleconnections. 相似文献
13.
The variability of dissolved organic carbon (DOC) over days to a multi-year time span has been investigated in the Gulf of Trieste (northern Adriatic Sea) over a period of 5 years (January 1999 to December 2003). Samples were collected in a grid of 9 to 12 stations on monthly frequency and in one station on weekly (2003) and daily (1-month) frequency. DOC samples were analyzed by the HTCO method. DOC concentration varied over the five years in the range of 50 to 194 μM with annual median values ranging from 88 to 98 μM. Over the years 1999–2002, DOC showed a clear annual periodicity with winter minima and late summer maxima, higher in 1999 and 2000. During 2003 no seasonality was detected. The absence of DOC seasonality and the lower DOC concentrations during 2003 are most likely related to the drought that characterized the whole year. Accumulation was calculated as the difference between averaged winter minima (59 ± 7 μM) and the monthly averaged integrated value. DOC that had accumulated from spring to summer totally disappeared from the water column in winter when DOC concentrations reached the background value. The Gulf of Trieste, as with the rest of the Northern Adriatic each year, seems to be able to bring back DOC concentrations at low levels despite the significant external (mainly Isonzo River inputs) and internal organic matter loads. DOC concentration exhibited quite wide fluctuations weekly and daily, suggesting there might be DOC of different turnover time through production, consumption, migration and accumulation. 相似文献
14.
The effects of tidal currents (i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons (May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia (ECPM), south of the South China Sea (SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal (O1 and K1) and semidiurnal (M2) tidal currents. The spectral density of residual currents (detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency (K1) and small peaks at the semidiurnal tidal frequency (M2) indicating the existence of internal tides. The result of the horizontal kinetic energy (HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux (16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is the highest in June and July. 相似文献
15.
Numerous CTD data obtained in the Eurasian and Makarov basins in the Arctic during the Polarstern (1996), Oden, and Louis S. St. Laurent (1994) international polar expeditions are analysed to describe fronts and intrusions observed in the deep layer (600–1300 m). The hydrological parameters were estimated from available CTD data, which made it possible to identify different types of fronts (baroclinic, thermohaline, and compound types of fronts) and analyze intrusive layering taking into account the peculiarities of the thermohaline structure of fronts. The field data are interpreted using an interleaving model describing the formation of intrusions on the baroclinic and pure thermohaline fronts under conditions of absolutely stable stratification. It is assumed that differential mixing is the main instability mechanism. Estimates of the vertical and lateral diffusivities in the frontal zones of the deep Arctic layer are presented. 相似文献
16.
珠江口东南近海海区污损生物研究 总被引：4，自引：2，他引：4
为研究珠江口东南近海海区污损生物状况,于1986年5月至1987年6月,在香港东南约114和160km,水深为95和113m处布设了两个生物浮标站,并对距香港约172km,水深为115m处的Marex水文气象浮标上的污损生物群落进行调查.此次调查共采集和鉴定出污损生物78种,其中在浸海只有3个月的试板上,主要有柄蔓足类、水螅和藻类,优势种是细板条茗荷、茗荷和直杯螅.至于浸海时间达6～12个月的浮标(包括沉标)及锚链系统,其上还有相当数量的多种双壳类软体动物、无柄蔓足类和苔藓动物等硬性污损生物附着.在种类垂直分布方面,污损生物群落组成随深度发生明显变化. 相似文献
17.
《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(9):1530-1548
With the aim of improving the knowledge of the open ocean carbon cycle, we present a budget of particulate organic carbon (POC) fluxes carried out in the deep central part of the Algero-Balearic Basin (ABB) at 2850 m water depth based on a single mooring equipped with five automated sediment traps deployed from April 2001 to May 2002 at depths of 250, 845, 1440, 2145 and 2820 m. Suspended particulate matter (SPM) and superficial sediments were also used as indicators of hydrodynamics and carbon burial, respectively. The data reveal that the fraction of primary production buried in the sediment, which finally leads to the sequestration of carbon dioxide from the atmosphere, is 0.16%, lower than the values found in the nearby continental margin regions such as the Alboran Sea (0.48–0.89%) but of the same order as recorded at other Mediterranean sites at similar depths, such as the Ionian Sea (0.11%). As they sink through the water column, the particles exhibit decreases in flux that are similar to those observed elsewhere, but also show variations that appear to correlate with hydrological features of the water masses present in the basin, as revealed by SPM concentrations and compositions. The input of the tyrrhenian deep water (TDW) into the ABB at 800–1500 m of water depth exhibits low suspended POC concentrations and low sinking POC fluxes were also observed in this depth range. Gulf of Lions water mass formation appears to also contribute to elevated suspended POC concentrations and perhaps POC accumulation in the traps and sediments by spreading of dense cold water along the whole ABB that supplied POC at depths higher than 2000 m. 相似文献
18.
《Deep Sea Research Part I: Oceanographic Research Papers》2006,53(5):869-893
This is a study about the spreading of newly formed deep waters following open ocean deep convection in the Northwestern Mediterranean Sea. The main results are from the SOFARGOS large scale float experiment initiated in 1994–1995. During the SOFARGOS project, CTD stations and Lagrangian observations of ocean currents were carried out in the Gulf of Lion from December 1994 to July 1995. Hydrological observations confirmed that deep water formation occurred very early during winter 1994–1995 (late December, early January) in conjunction with atmospheric cooling, deep convection penetrating down to 2000 m in the so-called Medoc area. Numerous eddies (both anticyclonic and cyclonic) drifted away from the convection area and advected newly formed deep waters far away from the source region. In particular, compact anticyclones appeared to be the most coherent (long-lived) eddies and capable of transporting newly formed Western Mediterranean Deep Waters several hundreds of kilometers away from the convection area. Characterized by an inner core of about 5 km in radius, these eddies are submesoscale features in the outer domain and appear as key elements of the open ocean convection processes. During their long journeys, these eddies interacted with larger scale features such as the Northern Boundary Current, the North Balearic Front, topographic Rossby waves, and Sardinian eddies. These interactions influenced the long-term behavior of the eddies (mean drift, composition) and represented an important part of (1) the spreading phase following deep convection and (2) the large scale thermohaline circulation. 相似文献
19.
The Bras d'Or Lakes are a system of interconnecting basins open through two narrow channels to the Sydney Bight at the mouth of the Gulf of St Lawrence. Hydrographic surveys between 1972 and 1974 showed that surface waters can warm by more than 10 °C from May to July and that horizontal salinity differences of up to 10 psu can exist between Sydney Bight (30 psu) and the innermost regions of the Lakes. Using the data from May and June 1974 to derive horizontal and vertical exchanges, a simple budget model has been set up consisting of two or three layers in each of nine separate regions. The model has a bottom inflow from Sydney Bight, deep inflow through the narrow channels to other basins and a surface outflow. The exchanges agree reasonably well with estimates derived from available current meter data. The model's predicted temperatures and salinities for July 1974 had rms errors of about 1·5 °C and 0·82 psu, respectively. The dissolved oxygen concentrations in four of the more isolated basins are similar to those calculated from the model, giving support to the derived circulation. 相似文献
20.
Impact of the winter cooling on the variability of the thermohaline characteristics of the active layer in the Black Sea 总被引：1，自引：0，他引：1
The influence of the winter atmospheric forcing on the interannual variability of the Black Sea’s active layer’s thermohaline
structure during 1982–2008 is investigated. The results are based on the combined analysis of the hydrological measurements
from a ship, satellite measurements of the sea’s surface temperature (SST), and the NCEP/NCAR reanalysis data for the surface
air temperature (SAT). A high correlation between the variability of the winter mean SST/SAT and the thermohaline characteristics
of the active layer during the following warm season was found. It is shown that the winter atmospheric forcing significantly
affects the variability of the temperature, salinity, and density down to the 150–200 m depth, and this has to be considered
in the analysis of the interannual and long-term variability of the Black Sea’s active layer. 相似文献