Biomarker responses to pollution in two invertebrate species: Scrobicularia plana and Nereis diversicolor from the Cádiz bay (SW Spain)

The clam Scrobicularia plana and the polychaete worm Nereis diversicolor were collected in several sites from a littoral enclosure in SW Spain. The aim of our study was to relate various biomarker responses in these species to a pollution gradient caused by untreated domestic discharges and to verify the adequacy of the selected species as sentinels in this habitat. The biomarkers selected were the antioxidant enzymes catalase (CAT), glutathione peroxidase (GPX) and DT-diaphorase (DT-D). In addition, the activities of cytochrome P450-dependent ethoxyresorufin O-deethylase (EROD) activity, the phase II detoxifying enzyme glutathione S-transferase (GST) and the neurotoxicity marker acetylcholinesterase (AChE) were measured. Metallothionein levels were selected as biomarkers of heavy metals exposure in both species. The results suggest a different response in the water filtering organism (clam) and the sediment eater (polychaete), probably as a consequent of different pollution exposure and that samples from the “Caño Sancti-Petri” were exposed to biologically active compounds that altered some of their biochemical responses. AChE was the most sensitive biomarker in both species and N. diversicolor proved to be a more robust sentinel in this ecosystem.     

Measurements of biomass and activity of neustonic microorganisms

Microlayer samples from a coastal marine area near Marseilles (France) collected in 1979 and 1980 have been analysed for POC, PON, chlorophyll a, ATP, cell counts, carbon fixation and in some cases for heterotrophic activity. Comparison of microlayer data with those of underlying water showed in most cases enrichment of organic matter and microorganisms in the surface microlayer. Carbon fixation values were comparable to those observed at 0·50 m except in the slicks, where phytoneustonic activity was higher than that of the underlying phytoplankton. Though total heterotrophic activity was higher in the surface film, the turnover time was not significantly different in both microlayer and underlying water. Our data show that enrichment is highly dependent on sea conditions; whenever slicks are present, the surface film seems to function like an eutrophic system, including active living material, although detritus is regularly present in large amounts.     

Nitrogen and phosphorus concentrations within North Inlet,South Carolina—Speculation as to sources and sinks

The daily concentrations of $\text{NH}{}_4{}^{\mathrm{+}}$, $\text{NO}{}_3{}^{\mathrm{?}}$, and $\text{NO}{}_3{}^{\mathrm{?}}\text{+ NO}{}_2{}^{\mathrm{?}}$ within the North Inlet system are all negatively associated with tidal stage during the late summer, this association breaking down during the winter. The high concentrations of these constituents during low tide coupled with the lack of streamflow during the late summer suggests that there is an internal source for these species. Ammonium and orthophosphate most likely have their source in sediment diffusion from tidal creek sediments and/or seepage from the vegetated marsh surface during tidal exposure. It is hypothesized that high nitrate plus nitrite values at low tide are caused by nitrification within the tidal water or tidal creek sediments. During the summer there is evidence for a source of dissolved organic nitrogen and dissolved organic phosphorus within the North Inlet system, probably via diffusion from creek sediments. In general the main source of dissolved organic nitrogen is via stream-flow from the adjacent watershed. Particulate nitrogen and phosphorus concentrations are a function of: (1) wind and rain events which cause resuspension of particulate material from the tidal creek banks, (2) rain events which scour the marsh surface during tidal exposure, and (3) high tidal velocities which scour the creek bottoms.     

The Use of Pigment Signatures to Assess Phytoplankton Assemblage Structure in Estuarine Waters

The seasonal dynamics of chlorophyll a and the main accessory pigments accompanied by microscopic observations on live and fixed material were investigated in the Urdaibai estuary, Spain. Fucoxanthin was the dominant pigment during the peak in chlorophyll a, with which it was strongly correlated. Concentrations of fucoxanthin (81·30 μg l⁻¹) in the upper estuary were amongst the highest found in the literature, and were mainly associated with diatoms and symbiotic dinoflagellates. In the lower estuary, fucoxanthin showed values typical of coastal waters (<5 μg l⁻¹) and was mainly due to diatoms and prymnesiophytes. Chlorophyllb concentration was high along the estuary, followed the same seasonal pattern as chlorophyll a, and was associated with the presence of euglenophytes, chlorophytes and prasinophytes. High values of 19′-butanoyloxyfucoxanthin were often measured, but no organisms containing this pigment were observed in live or fixed samples. Alloxanthin and peridinin were found in low concentrations which was in agreement with cell counts of cryptophytes and peridinin-containing dinoflagellates. Two main patterns of phytoplankton assemblages were observed along the estuary. In the upper segments, during the chlorophylla maximum fucoxanthin containing algae masked the other algal groups, which were relatively more abundant during or after enhanced river flows. In the lower estuary, although dominated by fucoxanthin-containing algae, the other algal groups were important all year around. In this study, the use of diagnostic pigments has provided considerable insight into the temporal and spatial dynamics of phytoplankton assemblages by detecting phytoplankton taxa generally underestimated or overlooked by microscopy.     

The chemistry of the anoxic waters in the Framvaren Fjord,Norway

In the summer of 1993, a number of chemical parameters (H₂S, O₂, pH, TA, TCO₂, NH ₄ ⁺ , PO ₄ ^3– , SiO₂, Mn²⁺ and Fe²⁺) were measured in the Framvaren Fjord, a permanently super-anoxic fjord in southern Norway. The extremely steep gradient of sulfide near the interface suggests that other than downward flux of oxygen, three other possible oxidants, particulate manganese and iron oxides, phototrophic sulfur oxidation bacteria and horizontally transported oxygen account for the oxidation of the upward flux of H₂S. Water intrusion through the sill accounts for the temperature inflection above the interface, which, together with internal waves (Stigerbrandt and Molvaer, 1988), may cause fluctuations of the depth of interface. Significant gradients of hydrographic properties and chemical species between 80–100 m suggest that there is a second interface at about 90 m that separates the deep and older bottom waters. A stoichiometric model is applied to examine the biogeochemical cycles of S, C, N and P in the Framvaren. High C:S, C:N and C:P ratios are found while the nutrients (N, P) have Redfield ratio. Based on the C:N:P ratio of 155:16:1 in organic matter, about 30% of sulfide produced by sulfate reduction is estimated to be removed by processes such as oxidation, formation of FeS₂, degassing and incorporation into organic matter. The rates of oxidation of H₂S by Mn and Fe oxides in the water near the interface were slightly faster than the observed values in the laboratory, probably due to the presence of bacteria.     

A Kalman Filter Approach to Realize the Lowest Astronomical Tide Surface

In this paper , we present a novel Kalman filter approach to combine a hydrodynamic model-derived lowest astronomical tide (LAT) surface with tide gauge record-derived LAT values. In the approach, tidal water levels are assimilated into the model. As such, the combination is guided by the model physics. When validating the obtained “Kalman-filtered LAT realization” at all tide gauges, we obtained an overall root-mean-square (RMS) difference of 15.1 cm. At the tide gauges not used in the data assimilation, the RMS is 17.9 cm. We found that the assimilation reduces the overall RMS difference by ～ 31% and ～ 22%, respectively. In the Dutch North Sea and Wadden Sea, the RMS differences are 6.6 and 14.8 cm (all tide gauges), respectively. Furthermore, we address the problem of LAT realization in intertidal waters where LAT is not defined. We propose to replace LAT by pseudo-LAT, which we suggest to realize similarly as LAT except that all water level boundary conditions and assimilated tidal water levels have to be enlarged by a constant value that is removed afterward. Using this approach, we obtained a smooth reference surface for the Dutch Wadden Sea that fits LAT at the North Sea boundary within a few centimeters.     

Chemical Composition and Geologic History of Saline Waters in Aux Vases and Cypress Formations, Illinois Basin

Seventy-six samples of formation waters were collected from oil wells producing from the Aux Vases or Cypress Formations in the Illinois Basin. Forty core samples of the reservoir rocks were also collected from the two formations. Analyses of the samples indicated that the total dissolved solids content (TDS) of the waters ranged from 43,300 to 151,400 mg/L, far exceeding the 35,400 mg/L of TDS found in typical seawater. Cl-Br relations suggested that high salinities in the Aux Vases and Cypress formation waters resulted from the evaporation of original seawater and subsequent mixing of the evaporated seawater with concentrated halite solutions. Mixing with the halite solutions increased Na and Cl concentrations and diluted the concentration of other ions in the formation waters. The elemental concentrations were influenced further by diagenetic reactions with silicate and carbonate minerals. Diagenetic signatures revealed by fluid chemistry and rock mineralogy delineated the water-rock interactions that took place in the Aux Vases and Cypress sandstones. Dissolution of K-feldspar released K into the solution, leading to the formation of authigenic illite and mixed-layered illite/smectite. Some Mg was removed from the solution by the formation of authigenic chlorite and dolomite. Dolomitization, calcite recrystallization, and contribution from clay minerals raised Sr levels significantly in the formation waters. The trend of increasing TDS of the saline formation waters with depth can be explained with density stratification. But, it is difficult to explain the combination of the increasing TDS and increasing Ca/Na ratio with depth without invoking the controversial 'ion filtration' mechanism.     

Isotopic composition and origin of mineral and geothermal waters from Tuşnad Băi Spa, Harghita Mountains, Romania

Different types of free water have been analysed for their deuterium and chemical composition in order to evaluate their source, mixing phenomena, and the underground dynamics. All types of ground water (mineral, geothermal and wellhead water) display δD values (− 82.6‰ to − 72.6‰) similar to surface waters from the studied area (− 77.1‰ to − 73.6‰). The global salt content varies from 1102 to 8707 mg/l for the groundwater, and from 46 to 392 mg/l for the surface water. From the co-variation between the δD values and the chemical composition of the waters, as well as from the seasonal variation of these two parameters, it is evident that the free water from Tuşnad Băi are meteoric in origin. The mineralization of the mineral water took place by means of an intense underground circulation, probably in the fault system developed within the Neogene magmatites.     

基于卫星高度计资料提取浙江近海的潮汐信息

利用Topex/Poseidon(T/P)、Jason-1和Jason-2卫星24a的原始轨道及6a的变轨轨道高度计资料,对浙江近海区域内进行潮汐调和分析,得到8个主要分潮(Q_1、O_1、P_1、K_1、N_2、M_2、S_2和K_2)的调和常数.比较卫星轨道交叉点处潮汐调和常数结果显示,8个分潮总体综合误差在原始轨道,变轨轨道及原始轨道与变轨轨道交叉点处的和方根RSS值分别为3.16、7.02、5.54cm;用卫星高度计资料及31个近岸验潮站得到的潮汐分布与21个验潮站资料结果进行比较,M_2、S_2、N_2、K_1和O_1主要分潮的多点向量均方根偏差分别为4.32、3.64、1.97、2.61、1.83 cm;本研究结果与前人数值模拟结果比较显示M2、S2分潮在对比点处的多点向量均方根偏差在11、8 cm左右,最后给出了浙江近岸及近海区域更为精确的5个主要分潮(M_2、S_2、N_2、K_1和O_1)的同潮图.     

福建沿岸不同海区夏季浮游植物的组成与分布

结合福建省“908专项”,于2006年7～8月对福建省沿岸海域水采浮游植物的种属组成、数量分布、生物量进行了大面积科学调查．结果表明,福建沿岸海域浮游植物隶属于6门57属127种,其中硅藻47属107种,甲藻5属15种,蓝藻1属1种,金藻2属2种,隐藻1属1种,裸藻1属1种．硅藻类在种类和数量上均占主导地位,优势种主要是柔弱伪菱形藻（Pseudo—nitzschia delicatissima）、中肋骨条藻（Skeletonema costatum）、旋链角毛藻（Chaetoceros curvisetus）、菱形海线藻（Thalassionema nitzschioides）等．硅藻类广布,甲藻类在闽东海域及东山沿岸分布较多,蓝藻类检出率降低,裸藻类和金藻类检出率增高．表层浮游植物平均细胞密度为3222．59×10^4ind／dm^3,数量分布态势为近岸高、外海低,阂东和闽南高、闽中低．叶绿素a及优势类群的分布与数量分布基本一致．福建沿岸海域赤潮生物种类较多,是引发赤潮的潜在生物因素,一些赤潮生物已在闽南、闽东沿岸局部海域成为优势种．