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Measurements of suspended particle concentration, size and settling velocity were made at a shallow site in the southern North Sea during a spring phytoplankton bloom. The site was characterised by strong differences in surface and near-bed residual flows; therefore particle processes in each layer are effectively decoupled as long as the water column is stratified. Four distinct energetic events during the observation period caused variation in the characteristics and behaviour of the particle population: (1) moderate spring tides with low wave activity; (2) strong winds, increased wave activity; (3) strong spring tides; (4) weak neap tides. During Event 1 weak tidal resuspension occurred, median particle diameter was relatively large, but median settling velocities of both chlorophyll and total SPM were low. During the higher energy Events 2 and 3 there was resuspension of relatively small, high-density particles producing high median total SPM settling velocities but low median particle diameter. In addition, a phytodetrital fluff layer, characterised by high chlorophyll settling velocity, was resuspended and dispersed during storm conditions (Event 2). During calm, weak neap tides (Event 4) there was negligible resuspension and enhanced particle settling and deposition, particularly in the phytodetritral component of the particle population, allowing rapid replenishment of the benthic fluff layer. This work indicates the relatively rapid rate at which fluff layers can be formed and dispersed, and highlights the need for high frequency measurements. The range of contrasting physical conditions over which the data-set was collected makes it an ideal candidate for parameterising and validating suspended sediment dynamics models. 相似文献
3.
An automated instrument (SEDVEL—Sedimentation Velocity) was developed to directly measure the mass-concentration and the mass-distribution of settling velocities of suspended particulate matter (SPM) in situ. This instrument consists of an underwater balance, which directly measures the variation in time of the immersed weight of particulate matter (PM) as it settles on a plate located at the bottom of a settling tube, under quiescent conditions. SEDVEL operates underwater and samples in situ for deployment periods of a few days. SEDVEL produced consistent and reproducible results when tested both in the laboratory and in the field under SPM dry-concentrations of 5 to 200 mg l− 1. Errors in the estimates of maximum dry-concentrations from SEDVEL measurements were less than 30% in 69% of the cycles analysed in the laboratory. The corresponding figure for in situ measurements was 50%. These errors are likely related to uncertainties in the calculation of the dry-density of flocs and in the definition of the zero position (ZP) of the SEDVEL balance. The slow settling particles/flocs (Ws < 1 mm s− 1) represented 32–98% of the total mass of SPM at two sites of deployment in Cleveland Bay (Australia). Distinct settling behaviours were observed between the two sites and among different tidal stages associated with differences in the floc population; the aggregation of which probably varied as a function of the bottom grain size, shear stress, resuspension, advection and organic content of SPM. 相似文献
4.
A tidal front is a unique structure in coastal waters where tidal mixing is dominant during the summer. Various indexes to define tidal fronts and their dynamics have been reviewed in coastal waters where tidal mixing is dominant. The classification of a front in coastal waters is determined by the freshwater inflow, heating/cooling, Ekman transport, and mixing intensity. The strength of mixing plays an important role, dynamically, in creating a tidal front. The hydrography and circulation around a tidal front are crucial in the biological processes leading to the cross-frontal transport of nutrients and phytoplankton blooms. Physical-biological cooperation is necessary to clearly assess the impact of a tidal front on the distribution of phytoplankton and chlorophyll a in the tidal front area. 相似文献
5.
现代黄河三角洲沉积物临界剪切应力研究 总被引：2，自引：1，他引：1
为研究现代黄河三角洲沉积物临界剪切应力空间分布特征及其影响要素,本文在现代黄河三角洲不同沉积区域,垂直海岸线布设测线,采用黏结力仪进行沉积物临界剪切应力测试,并在相应测点开展沉积物物理力学性质与粒度成分测量工作。研究结果表明高潮滩沉积物临界剪切应力最高,在1.1~4.02Pa之间,沉积物不易发生侵蚀,含水量低、干容重大、黏粒与粉粒含量高、平均粒径小、不排水剪切强度大是高潮滩沉积物临界剪切应力偏高的重要因素;中潮滩沉积物受生物活动影响显著,临界剪切应力在0.10~1.90Pa之间,生物活动扰动、生物排泄及遗体遗迹的程度与数量是造成不同区域测试差异的重要原因;低潮滩沉积物临界剪切应力很低,在0.08~0.80Pa之间,沉积物极易发生侵蚀,含水量高、干容重偏低、砂砾含量高、平均粒径大、不排水剪切强度小是其典型的沉积物物理力学性质,也是造成低潮滩沉积物临界剪切应力普遍低于高潮滩的重要原因;现代黄河三角洲沉积物临界剪切应力区域特征表现为北部沉积物临界剪切应力水平最低,在0.11~0.4Pa之间,东部最高,在2.8~4.55Pa之间,南部与东北部居中,分别在0.63~0.84Pa与0.83~2.99Pa之间,东北部空间非均匀性分布显著,粒度组分的分异是导致沉积物临界剪切应力区域差异显著的重要因素,黏粒含量高的沉积区域沉积物临界剪切应力普遍高于砂砾含量高的沉积区;与世界其他大型河口三角洲相比,现代黄河三角洲沉积物临界剪切应力水平偏低但非均匀程度较高。 相似文献
6.
A. Mantovanelli E. Marone E. T. da Silva L. F. Lautert M. S. Klingenfuss V. P. Prata Jr. M. A. Noernberg B. A. Knoppers R. J. Angulo 《Estuarine, Coastal and Shelf Science》2004,59(4):523-537
Net transports of water, salt and suspended particulate matter (SPM) for a cross-section in front of the Paranaguá Harbour (Paranaguá Bay, Brazil) are presented for eight distinct tidal cycles. Data include measurements over single spring and neap tidal cycles, during both wet and dry seasons. The main drive forces of circulation and SPM dynamics are identified. Advective transport dominated under moderate to high vertical salinity stratification and weak currents, while mixing processes dominated under well-mixed conditions generated by high currents and low freshwater input. Under partially mixed conditions, both advective and mixing processes were important. The tide-induced residual circulation dictated the magnitude and direction of residual currents and net transports of water and salt, but not of SPM transport. The SPM dynamics was intrinsically related to cyclical processes of erosion, resuspension and deposition driven by tidal currents. The turbulent mixing intensity conditioned the vertical mixing of SPM. Resuspension and vertical mixing were conspicuous in spring cycles, while the horizontal advection preponderated in the neaps. Lags between maximum currents and SPM peak concentrations occurred, with more pronounced hysteresis during ebb periods. 相似文献
7.
R.J. Uncles A.J. BaleJ.A. Stephens P.E. FrickersC. Harris 《Estuarine, Coastal and Shelf Science》2010
Measurements are presented of median floc diameters and associated environmental data over spring-tide tidal cycles at two stations in the muddy Tamar Estuary, UK, for winter, spring and summer conditions. The particulate organic carbon and particulate total carbon contents of mudflats and SPM (suspended particulate matter) at the stations, together with other evidence, indicates that much of the SPM was derived from mud sources that were located between the two stations during winter and spring, and from very mobile sediment sources in the upper estuary during summer. Observed in-situ median floc sizes varied widely, from <50 to >500 μm and rapid settling of particles close to HW and LW (high and low water) left only the smaller flocs in suspension. Time-series of depth-averaged median floc sizes generally were most closely, positively, correlated with depth-averaged SPM concentrations. Floc diameters tended to reach maximum median sizes near the time when SPM concentrations were highest. These high concentrations were in turn largely generated by resuspension of sediment during the fastest current speeds. Although such correlations may have arisen because of SPM-driven floc growth - despite fast tidal currents - there is also the possibility that tough aggregates were eroded from the intertidal mudflats and mudbanks. Although a hypothesis, such large aggregates of fine sediment may have resulted from the binding together of very fine bed particles by sticky extracellular polymeric substances (EPS) coatings, produced by benthic diatoms and by other biologically-mediated activity. A rapid reduction of SPM occurred at the up-estuary station within 2.5 h of HW on the flood, when decelerating currents were still relatively fast. It appears that at least two processes were at work: localised settling of the largest flocs and up-estuary transport in which large flocs were transported further into the estuary before settling into the Tamar's ETM (estuarine turbidity maximum) over the HW-slack period. Up-estuary advection of large flocs and their eventual settling would place the down-estuary edge of the ETM above the upper-estuary station during summer, spring-tide conditions. This position of the ETM was observed close to HW during longitudinal surveys of the estuary. 相似文献
8.
磷元素是海洋基础营养盐之一,其赋存形态及分布直接影响海区的初级生产力,是海洋生物地球化学循环的重要驱动力。但大河河口与近海等重要的水生关键带水动力循环过程复杂,导致悬浮颗粒物(SPM )中磷元素的赋存形态和分布特征变化多端,亟须深入研究。根据2016年春季(4?5月)、夏季(7月)和秋季(9?10月)对浙江近岸海域的调查结果,本研究分析了浙江近岸海域SPM中总磷(TPP)、无机磷(PIP)和有机磷(POP)的含量水平、空间分布特征和影响因素。结果表明,浙江近岸海域SPM中TPP含量范围为0.13～66.13 μmol/L,均值为3.35 μmol/L;PIP含量范围为0.03～34.19 μmol/L,均值为1.97 μmol/L;POP含量范围为0.06～31.94 μmol/L,均值为1.39 μmol/L。PIP是浙江近岸海域水体中TPP的主要存在形式,占52.3%。春季浙江近岸海域表层TPP含量占总磷(TP)含量的19.3%～97.7%。春、秋季的SPM中,TPP、PIP和POP含量空间分布相似,均呈现由内湾向外海逐渐降低的变化趋势。PIP、POP与SPM呈显著的正相关性,表现出高SPM含量的海区有着较高的颗粒态磷含量,说明其受陆源输入的影响。春季盐度大于28且SPM含量小于20 mg/L的外侧远海海域,POP与Chl a的相关系数和斜率均明显高于PIP与Chl a的相关系数和斜率,说明该区域浮游植物是POP的主要贡献来源。 相似文献
9.
The fate of fine particulate material in aquatic environments is closely linked to aggregation and disaggregation processes. Understanding the mechanisms controlling these processes is fundamental to the development of predictive models of fate and effects for particulate discharges in the coastal zone from such sources as offshore hydrocarbon exploration and development. One of the variables required for the development of these models is maximal floc size. Using a non-invasive imaging technique, the significance of turbulence, composition, and concentration on maximal floc size in an inverting column flocculator was determined for materials commonly discharged during offshore hydrocarbon development. The settling velocity of the suspension was determined from volume concentrations of samples obtained by pipette during still water settling in a manner similar to that of Owen tubes. After 20 h, both maximal floc size and settling velocity showed a highly significant dependence on turbulence and type of material in suspension, but showed no effect from concentration. 相似文献
10.
Iron, Mn, Cu, Pb and Zn have been determined in suspended particulate matter (SPM) collected in the estuarine plume regions of the Humber (during winter, spring and summer) and Thames (winter only). Metal concentrations (w/w) were found to increase with SPM concentration and could be defined in terms of the mixing of an ambient, slow settling population, with variable proportions of a diluent population. The end-members of the particle mixing series are fine material derived from coastal erosion, which is modified seasonally by biological production, and contaminated estuarine material which is contained within the estuarine discharge or derived from local resuspension of reworked deposits by tidal currents and wave activity. Iron-normalized metal concentrations exhibited an inverse relationship with SPM concentration in the Humber region and regression analyses enabled seasonal changes in end-member compositions to be evaluated. Since the metal:Fe ratios of the ambient population did not accord with those of local cliff samples, additional sources of metal were proposed whose importance to particle composition increases with a reduction in SPM concentration. Qualitatively, the seasonal variation of end-member compositions was consistent with (i) the coupling between redox processes occurring in the bed sediment and adsorption of metals (Mn, Cu, Zn) released from the pore waters onto ambient and diluent suspended particles in the overlying water column, and (ii) adsorption of metal (Pb) by ambient suspended particles from an extraneous (atmospheric) source. In the Thames plume, an increase in Fe-normalized metal concentrations with increasing particle concentration resulted from the mixing of end-member particles and the effects of additional metal from an internal or extraneous source were less clear, possibly because of metal desorption from suspended particles traversing the salinity gradient in the outer estuary. The processes described in this study regulate the internal cycling of trace metals in estuarine plume regions and the export of metals to neighbouring shelf sea environments. 相似文献
11.
The prediction of large-scale coastal and estuarine morphodynamics requires a sound understanding of the relevant driving processes and forcing factors. Data- and process-based methods and models suffer from limitations when applied individually to investigate these systems and, therefore, a combined approach is needed. The morphodynamics of coastal environments can be assessed in terms of a mean bed elevation range (BER), which is the difference of the lowest to highest seabed elevation occurring within a defined time interval. In this study of the coastal sector of the German Bight, North Sea, the highly variable distribution of observed BER for the period 1984–2006 is correlated to local bed shear stresses based on hindcast simulations with a well-validated high-resolution (typically 1,000 m in coastal settings) process-based numerical model of the North Sea. A significant correlation of the 95th percentile of bed shear stress and BER was found, explaining between 49 % and 60 % of the observed variance of the BER under realistic forcing conditions. The model then was applied to differentiate the effects of three main hydrodynamic drivers, i.e. tides, wind-induced currents, and waves. Large-scale mapping of these model results quantify previous qualitative suggestions: tides act as main drivers of the East Frisian coast, whereas waves are more relevant for the morphodynamics of the German west coast. Tidal currents are the main driver of the very high morphological activity of the tidal channels of the Ems, Weser and Elbe estuaries, the Jade Bay, and tidal inlets between the islands. This also holds for the backbarrier tidal flats of the North Frisian Wadden Sea. The morphodynamics of the foreshore areas of the barrier island systems are mainly wave-driven; in the deeper areas tides, waves and wind-driven currents have a combined effect. The open tidal flats (outer Ems, Neuwerker Watt, Dithmarschen Bight) are affected by a combination of tides, wind-driven currents and waves. Model performance should be measurably improved by integrating the roles of other key drivers, notably sediment dynamics and salt marsh stabilisation. 相似文献
12.
最近50a来莱州湾西—南部潮流动力演变的数值模拟研究 总被引：1，自引：0，他引：1
根据1959、1984、2002年测量的海图,基于二维浅水方程分别构建了3个年份的莱州湾潮流场模型,研究了最近50a来莱州湾西—南部潮流动力演变规律,揭示黄河河口沙嘴形成演变对莱州湾西—南部潮流动力的影响。结果表明,最近50a中在沙嘴外围一直存在弧形高流速带,在弧形高流速带外围又有潮流剪切锋,潮流剪切锋包括内涨外退式和内退外涨式两类。随着河口沙嘴的不断向海延伸,莱州湾西—南海域的等潮位线呈以沙嘴为中心的辐射式格局;弧形高流速带整体向外海移动,其范围和流速也随之不断增大;剪切锋历时变长、间隔时间变短、南北跨度变大;但弧形高流速带和潮流剪切锋始终位于青坨子以北海域。对照同期海岸地貌演变,在弧形高流速带、潮流剪切锋等共同作用下,大部分黄河入海泥沙的输运路径和沉降范围仅限于青坨子以北,导致海岸地貌以此为界呈现显著的差异性演化。 相似文献
13.
Observations and analyses of floc size and floc settling velocity in coastal salt marsh of Luoyuan Bay, Fujian Province, China 总被引：1，自引：0，他引：1
In coastal environments, fine-grain sediments often aggregate into large and porous flocs. ElectroMagnetic Current Meters (EMCM) and Laser In Situ Scattering and Transmissometry (LISST-ST) have been deployed within a Spartina alterniflora marsh of the Luoyuan Bay in Fujian Province, China, to measure the current velocity, the floc size and the settling velocity between 15 and 22 January 2008. During the observations, the near-bed water was collected in order to obtain the suspended sediment concentration (SSC) and constituent grain size. Data show that: (1) the nearbed current velocities vary from 0.1 to 5.6 cm/s in the central Spartina alterniflora marsh and 0.1–12.5 cm/s at the edge; (2) the SSCs vary from 47 to 188 mg/dm 3 . The mean grain size of constituent grains varies from 7.0 to 9.6 μm, and the mean floc sizes (MFS) vary from 30.4 to 69.4 μm. The relationship between the mean floc size and settling velocity can be described as: w s =ad b , in which w s is the floc settling velocity (mm/s), a and b are coefficients. The floc settling velocity varies from 0.17 to 0.32 mm/s, with a mean value of 0.26 mm/s, and the floc settling velocity during the flood tide is higher than that during the ebb tide. The current velocity and the SSC are the main factors controlling the flocculation processes and the floc settling velocity. 相似文献
14.
C. F. Jago S. E. Jones R. J. Latter R. R. McCandliss M. R. Hearn M. J. Howarth 《Journal of Sea Research》2002,48(4)
Suspended particulate matter (SPM) concentration and properties (particle size and settling velocity), water column and boundary layer dynamics were measured during a 60-d period at a site in 110 m water depth in the northern North Sea. The site was in stratified waters and measurements were made during September–November as the seasonal thermocline was progressively weakening. SPM concentration was low, c. 1 mg dm−3 in the surface mixed layer and maximum values of 2 mg dm−3 in the bottom mixed layer. The bottom layer was characterised by larger mean particle size. SPM signals in the two layers were decoupled at the start of the period, when the thermocline was strong, but were increasingly coupled as the thermocline progressively weakened. A spring-neap cycle of resuspension and deposition of SPM was observed in the bottom mixed layer. Bed shear stresses were too small to entrain the bottom sediment (a fine sand) but were competent to resuspend benthic fluff: threshold bed shear stress and threshold current velocity at 10 mab were 0.02–0.03 Pa. and 0.18 m s−1, respectively. Maximum SPM concentration in the bottom layer preceded peak spring tide currents by 3 d. Simulation of fluff resupension by the PROWQM model confirms that this was due to a finite supply of benthic fluff: the fluff layer was stripped from the seabed so that fluff supply was zero by the time of peak spring flow. SPM was redeposited over neap tides. Fluff resuspension must have been enhanced by intermittent inertial currents in the bottom layer but unequivocal evidence for this was not seen. There was some resuspension due to wave activity. Settling velocity spectra were unimodal or bimodal with modal values of 2×10−4–2×10−3 mm s−1 (long-term suspension component) and 0.2–5.7 mm s−1 (resuspension component). The slowest settling particles remained in suspension at peak spring tides after the fluff layer had been exhausted. There was evidence of particle disaggregation during springs and aggregation during neaps. 相似文献
15.
桑沟湾夏、秋季悬浮颗粒物的沉降通量及再悬浮的影响 总被引：1，自引：0，他引：1
应用锚式悬挂沉积物捕捉器法,研究了我国北方重要海水养殖区域桑沟湾悬浮颗粒物沉降通量的分布特征,并通过金属Al标记法,同步测定了沉降颗粒物再悬浮比率。结果表明,桑沟湾的底层悬浮颗粒物(SPM)、颗粒有机碳(POC)、颗粒态总氮(PTN)和颗粒态总磷(PTP)平均表观沉降通量分别为1 511.4g/(m2·d)、20.01g/(m2·d)、1.497g/(m2·d)和0.474g/(m2·d),显著高于我国其他近岸海域,但底层沉降颗粒物再悬浮比率平均值高达92.8%,认为在养殖内湾,受再悬浮程度的影响,测得的底层表观沉降通量是中层的2.7倍,秋季明显大于夏季,海带和扇贝养殖区大于牡蛎养殖区。经再悬浮比率校正后的净沉降通量,仍存在着显著的空间和季节变化,但受控因素发生了根本转变;这主要表现为净沉降颗粒物质主要源于生物代谢活动强烈中上层水体,贝类的排泄作用使牡蛎和扇贝养殖区的净沉降通量显著大于海带养殖区,养殖贝类个体增大、排泄量增加使秋季净沉降通量高于夏季。在我国近岸海域,再悬浮作用的影响,会对该区域悬浮颗粒物沉降通量的估算带来巨大误差,因此该作用不容忽视。 相似文献
16.
Th. Leipe A. Loeffler K. -C. Emeis S. Jaehmlich R. Bahlo K. Ziervogel 《Estuarine, Coastal and Shelf Science》2000,51(6):789
Suspended particulate matter samples were collected from the water column, the bottom nepheloid layer and the ‘ fluffy layer ’ from four stations along a coastal-basin transect in the Pomeranian Bight, western Baltic Sea. Sampling was performed nine times between October 1996 and December 1998 for various analyses, including electron probe x-ray micro analysis for detailed mineralogical investigations.Specific vertical patterns of clay mineral distributions were found. Suspended particulate matter (SPM) in the bottom nepheloid layer and the ‘ fluffy layer ’ overlying sediments was enriched in organic carbon and hydrated three layer clay minerals, whereas the non-aggregated SPM was dominated by quartz and biogenic opal. It appears that separation effects operate during aggregation of mineral particles and organic matter in repeated cycles of resuspension and settling. No clear seasonal variations in the composition of the SPM were found, in spite of high spatial and temporal variability of biological and physical variables. The results suggest that preferential incorporation, possibly aided by microbiological colonization, of hydrated three layer silicates into the organic flocs is a process that occurs under a wide range of conditions. Because aggregates sink faster than individual particles, aggregate formation led to a relative enrichment of illite and smectite in the near-bottom layers. Considering the affinity of organic contaminants and heavy metals to organic matter, the selective removal of aggregated organic matter and hydrated three-layer clay minerals from the water column and enhanced transport in the near-bottom fluffy layer may be a natural cleansing mechanism operating in the shallow waters of the bight. 相似文献
17.
《Oceanologica Acta》2002,25(1):39-49
In June and September of 1999, a LISST-100 in situ laser diffraction particle sizer was used to analyse the temporal and spatial variation of the beam attenuation coefficient, the in situ median particle (aggregate) diameter and the median volume concentration of suspended matter in two Danish coastal water bodies. One of the study sites was generally exposed to wind, while the other was quite sheltered. Measurements of the mass concentration of total suspended matter and chl a were made simultaneously. The in situ median effective density, settling velocity and vertical flux of the suspended matter are computed. Results demonstrate that in September, the in situ median aggregate diameter, settling velocity and vertical flux was smaller (by a factor of up to 16) and the concentration higher (by a factor of up to almost two) than in June. This is attributed to varying degrees of turbulence in the water in the weeks preceding the field work, causing aggregates to break up (lowering in situ aggregate diameter and settling velocity) and sediment to be resuspended (increasing concentration) in September. The fractal dimension of the suspended aggregates is estimated. The fractal dimension is found to increase from June to September at both study sites, supporting the notion of aggregate break-up in September due to turbulence in the upper part of the water column. An algae bloom occurred at the sheltered study site in September. In situ particle size spectra from this site demonstrated increasing aggregate sizes towards the bottom. It is suggested, that the increase in size is due to biologically induced aggregation, causing large aggregates to settle out of the upper part of the water column, leaving finer particles and aggregates behind. 相似文献
18.
Yang Yang Ya Ping Wang Chunyan Li Shu Gao Benwei Shi Liang Zhou Dandan Wang Gaocong Li Chen Dai 《Geo-Marine Letters》2016,36(2):135-149
Interactions between turbulence, suspended sediment concentration (SSC), settling velocity, effective density, fractal dimension, and floc size were studied on the tide-dominated, muddy coastal shelf of the southwestern Yellow Sea, China. The measurements were carried out in July 2013 at two sites located in water depths of 21.2 and 22.1 m. Negative correlations were observed between shear rate, SSC, effective density, and mean floc size, which supports the results of previous numerical, experimental, and field studies. A significant positive correlation was observed between near-bed SSC and shear rate, an indication that SSC variations are controlled by turbulence and re-suspension. In addition, significant linear relationships were found between settling velocity and other parameters (floc size, turbulence, SSC, effective density, and fractal dimension) at the two sites, indicating that the controlling factors on settling velocity are spatially variable. Principal component analysis was applied to determine the relative importance of turbulence, flocculation ability, and SSC as controls on floc size in situ. The relative contributions of turbulence, flocculation ability, and SSC to floc size (at both sites) were ~33.0%, 30.3%, and 29.7%, respectively, this being a new field-based quantitative analysis of the controls on floc size. The findings demonstrate that, in nature, flocculation ability affects floc size to the same degree as turbulence and SSC. Therefore, predictions of floc size in coastal marine environments require constraints not only on turbulence and SSC, but also on flocculation ability. 相似文献
19.
以实测悬沙粒径、流速、含沙量资料为基础,通过悬沙不同粒级组分、中值粒径以及粒度参数的统计,分析椒江河口最大浑浊带核部悬沙粒径分布变化特性。研究表明,悬沙粒径分选主要受物质来源、潮流动力作用下底部部分物质再悬浮和絮凝沉降3个因素的影响。其中第二个因素起主导作用,大潮期比小潮期显著,第三个因素的作用主要发生在涨落憩前后低流速期,并在表层较近底层的水体明显。 相似文献
20.
厦门湾水体中不同粒级颗粒物、Chl-a和234Th随潮汐的变化及其海洋学意义 总被引：3，自引：0，他引：3
在沿岸海域——厦门湾的定点观测站,研究了不同粒径悬浮颗粒物(SPM)、Chl-a和^234Th随潮汐的变化,结果表明,不管采样深度和粒级大小,Chl-a浓度的潮汐变化均为高潮大于低潮．SPM浓度的潮汐变化,表层的规律性很明显,即不管是第一天还是第二天,也不管粒径的大小,SPM浓度无例外地呈现高潮小于低潮之势．从不同粒径SPM、Chl-a的潮汐变化的比较可以看出,浮游植物等生源颗粒物在该研究水域的颗粒物中所占比例很小,颗粒物主要来自九龙江河流输入的悬浮物和表层沉积物的再悬浮．在沿岸海域,颗粒态^234Th是总^234Th的主要组成部分,^234Th各粒级的比活度均呈现高潮大于低潮的普遍趋势,基于^234Th估算的沿岸POC、PON等输出通量也存在潮汐变化的影响．文中对上述研究对象随潮汐变化的原因作了分析和讨论． 相似文献