Extreme events and environmental changes: Tracing sedimentary processes in Central Vietnam coastal lagoons

Sediment cores, obtained in 2004–2005 and in 2008 from seven coastal lagoons of Central Vietnam (Lang Co, Nuoc Man, Nuoc Ngot, Thi Nai, O Loan, Thuy Trieu and Dam Nai), were analysed to assess changes in ²¹⁰Pb, porosity, grain size, and depth distributions of selected major and trace elements (Al, As, Ni, and Zn). The aim was to trace sedimentary processes in areas periodically subject to extreme events. The occurrence of lateral sedimentary inhomogeneities has been hypothesised to explain the differences observed at depth for some tracer profiles, whereas topmost levels present evidence that accounts for the loss of a sediment layer (from 2.0 to 7.5 cm thick) between the two samplings. These losses might be attributed to major typhoons that impacted the coasts of Central Vietnam during the study period.     

The occurrence of glycolic acid in coastal sea water

A reasonably fast and reliable chemical method for the determination of glycolic acid in sea water is described in detail. It consists of adsorption of glycolic acid by alumina, followed by extraction with sulphuric acid and then colorimetry. The overall efficiency of recovery of this method, which is standardized internally, is approximately 67%, and about 20-fold concentration of glycolic acid is achieved. Using this method, the occurrence of glycolic acid in Ipswich Bay (Gulf of Maine, USA) was studied over a period of 6 months and was found to fluctuate between 0 and 80 g/l. The zero values occurred in January, when the phytoplankton chlorophyll values were also at their winter minimum.     

Towards an effective framework for coastal zone management: the Egyptian experience

Coastal areas are among the most highly populated, most exploited areas and vulnerable ecosystems in the world. How these interface areas between terrestrial and marine environments can effectively planned and managed has proved to be extremely challenging. Integrated Coastal Zone Management (ICZM) has been promoted as a potential panacea for the effective planning and management of these areas. However achieving such goals for ICZM is complex because of the many human activities and diverse regulatory regimes in coastal areas requires effective integration along many dimensions. Within the context of the developing world, which is often characterised by highly centralised governance systems combined with a lack of effective public and stakeholder participation in planning delivering an effective ICZM, which is drawn from collaborative planning ideas has proved particularly problematic. Furthermore within these countries there have been few critical and analytical evaluations of why ICZM experiments have failed. This paper seeks to begin to address this gap by suggesting that Actor Network Theory (ANT) is an appropriate analytical framework to critically evaluate why ICZM initiatives in Egypt, at both the national and local level, have been relatively unsuccessful. The critical evaluation leads to some practical recommendations that could help to enhance the implementation of ICZM in Egypt.     

Fate of large-scale vortices in idealized tidal lagoons

Environmental Fluid Mechanics - The generation and evolution of tidally-induced vortices in coastal and estuarine regions can influence water quality and sedimentary processes. These effects must...     

Sensitivity and robustness of Lagrangian coherent structures in coastal water systems

Environmental Fluid Mechanics - In coastal water systems, horizontal chaotic dispersion plays a significant role in the distribution and fate of pollutants. Lagrangian Coherent Structures (LCSs)...     

Sediment nutrient flux in a coastal lake impacted by diverted Mississippi River water

The internal nutrient load from bottom sediment to the water column of a Louisiana Barataria Basin lake (Lake Cataouatche) receiving diverted Mississippi River water was determined. Dissolved reactive phosphorus (DRP), ammonium (NH₄-N) and nitrate (NO₃-N) flux from sediment to water column were measured. The DRP flux averaged-0.22 mg m^-2 d^-1 under aerobic water column conditions, as compared with that 3.29 mg m^-2 d^-1 under anaerobic conditions. The average NH₄-N released under anaerobic conditions (1.42 mg m^-2 d^-1) was significantly greater than rates under aerobic conditions (-0.02 mg m^-2 d^-1), indicating a strong relationship between nutrient flux and oxygen availability in the water column. The average NO₃-N flux was 2.13 mg m^-2 d^-1 under aerobic conditions as compared with-0.24 mg m^-2 d^-1 under anaerobic conditions in the sediment-water column. When the water column maintained under anaerobic conditions was switched to aerobic conditions, the DRP, NH₄-N, and NO₃-N concentrations in overlying water decreased rapidly over a short period of time. The mean annual internal DRP and NH₄-N load from the sediment to the overlying water was estimated to be 69.26 and 29.9 tonnes (Mg) yr^-1 respectively, which represents a significant portion of the total nutrient load to the Lake. Results demonstrate that the internal flux of nutrients from sediments can contribute a significant portion of the total nutrient load to the water column and should be considered in decisions on impact of nutrient in diverted Mississippi River on water quality of Barataria Basin.     

Metal partitioning in sediment pore water from the Ondo coastal region,Nigeria

Distribution and equilibrium partitioning of metals (Cd, Cu, Cr, Fe, Ni, Pb, Mn, and Zn) between pore water and surface sediments at the Ilaje coast of Ondo State, Nigeria, were studied. The Ilaje River can be one of the interesting research locations because of its economic nature and history of oil pollution. Seasonal variations were observed to investigate possible variations in the availability of metals for organisms throughout the year. The concentrations in both sediments and pore water during the dry and wet seasons were as follows: Cu?>?Fe???Mn?>?Pb?>?Ni?>?Cr?>?Cd?>?Zn. The pore water–sediment partition coefficient (K _p) showed that Zn and Cd were highly mobile while Fe and Cu have restricted mobility. Dissolved organic carbon (DOC) in pore water had a strong influence on mobility and bioavailability of all the metals (p?K _oc), increased levels of Fe and Cu were linked to lithological origin. Concentrations of Pb and Ni were associated with petroleum-related sources. The significance of the field-based techniques for ecotoxicological purposes is discussed.     

Response of a Fuzzy INdex of Ecosystem integrity (FINE) to water and sedimentary chemical data in two northern Adriatic lagoons

The European WFD (2000/60/EC) requires the assessment of the ecological quality status of water bodies, and gives great importance to the biological components of the ecosystem. A multimetric, fuzzy-based index for the evaluation of environmental quality (FINE: Fuzzy INdex of Ecosystem integrity) has been developed. The FINE index was calculated at 7 sites in the Sacca di Goro and the Valli di Comacchio (Adriatic Sea), where water and sedimentary chemical data were available for the years 2004 and 2005. A significant positive correlation was found between FINE values and dissolved oxygen, while significant negative correlations were observed between FINE values and transparency, nitrogen and phosphorous in the water column, and heavy metals and PCB in the sediments.     

Response of a Fuzzy INdex of Ecosystem integrity (FINE) to water and sedimentary chemical data in two northern Adriatic lagoons

The European WFD (2000/60/EC) requires the assessment of the ecological quality status of water bodies, and gives great importance to the biological components of the ecosystem. A multimetric, fuzzy-based index for the evaluation of environmental quality (FINE: Fuzzy INdex of Ecosystem integrity) has been developed. The FINE index was calculated at 7 sites in the Sacca di Goro and the Valli di Comacchio (Adriatic Sea), where water and sedimentary chemical data were available for the years 2004 and 2005. A significant positive correlation was found between FINE values and dissolved oxygen, while significant negative correlations were observed between FINE values and transparency, nitrogen and phosphorous in the water column, and heavy metals and PCB in the sediments.     

Assessment of distubance in Mediterranean lagoons: An evaluation of methods

A number of methods were applied to assess disturbance in macrozoobenthic communities in three Mediterranean lagoons with different levels of stress. Tsopeli, Ionian Sea, with no obvious source of stress, harbours a fauna typical of brackish-water lagoons. Vivari, Aegean Sea, also without apparent source of disturbance, is characterised by a few typical lagoonal species and some species characteristic of perturbation. Goro lagoon, in the northern Adriatic, is much larger and more open to the sea. At the centre of the lagoon, where anoxia is known to occur in the summer (Goro polluted), the fauna is dominated by species typical of disturbance and a few lagoonal species. A dredged area closer to the sea (Goro dredged) is totally dominated by species characteristic of disturbance. The species diversity in all lagoons ranges from low to very low. According to the distribution of individuals in geometric abundance classes, all the lagoons are characterised as stressed. The distribution of individuals in geometric size classes shows dominance of larger specimens in the least disturbed Tsopeli and exclusively small sizes in the greatly disturbed dredged area of Goro. The abundance/biomass comparison curves characterise Tsopeli as undisturbed, Vivari and Goro polluted stations as moderately disturbed and Goro dredged station as disturbed. The last two methods agree with the characterisation derived by examining the dominant species. It is concluded that methods based on size changes of the fauna are more sensitive than those based on relative abundance in assessing disturbance in coastal brackish-water lagoons.     

三丁基锡对中国近海常见海洋微藻的毒性效应

研究三丁基氯化锡(TBT)对中国近海常见5种硅藻和甲藻(硅藻中丹麦细柱藻(Leptocylindrus danicus)、派格棍形藻(Bacilaria paxillifera)、聚生角毛藻(Chaetoceros socialis),甲藻中微型原甲藻(Prorocentrum minimum)、简裸甲藻(Gymnodinium simplex))的毒性效应,考察了有机锡对浮游藻光合活性(Fv/Fm)、粒径、生长的影响。结果表明:派格棍形藻、聚生角毛藻、简裸甲藻的光合活性(Fv/Fm)受TBT影响较显著;微型原甲藻、丹麦细柱藻的光合活性受TBT影响较小。高质量浓度TBT胁迫下海洋微藻峰值粒径显著减小,低质量浓度TBT对峰值粒径影响不显著。低质量浓度TBT对派格棍形藻、聚生角毛藻、简裸甲藻、微型原甲藻均有较强的毒性作用,非检测毒性浓度(NDEC)分别为1.17、1.07、0.23、3.73μg.L-1,丹麦细柱藻对TBT具有很强耐受性,NDEC为112.62μg.L-1。     

Life cycle, seasonal vertical distribution and feeding of Calanus finmarchicus in Skagerrak coastal water

 Day/night zooplankton sampling in Kosterfjorden, Sweden, gave information on population succession, vertical distribution and feeding of Calanus finmarchicus over 17 months. Copepodid Stage 1 and 2 (C-I, C-II) were present from December to August, indicating reproduction during most of the year. Mating and breeding for the overwintering generation mainly took place in February/March, resulting in peak abundance of C-I in March/April. Secondary breeding periods were in April and July/August, but the resulting recruitment from these were low. The relative recruitment success in the first spring was around 13 times higher than during the second spring. Low temperature in the surface water early in the year and depression of the spring phytoplankton bloom may have caused the failure in the second year. Population biomass peaked at >15 g dry weight m⁻² during the numeric peak of the youngest stages in March/April. A more sustainable level of high biomass of 8 to 10 g dw m⁻² was gradually built up during summer, mainly due to a continuous accumulation of C-Vs. Adults and C-Vs comprised the overwintering population, with 7 to 14% and 85 to 93%, respectively, for the 2 years, but only C-Vs staying in the deep water were in a resting state. Adult males showed a strong diurnal vertical migration (DVM) of the usual type from spring to early autumn and a reversed DVM during the cold season. They were in a feeding state throughout the year. Adult females showed the usual type of DVM during summer to autumn, but commonly a reversed DVM during winter to spring. They were usually in a feeding state, with no pronounced differences between surface and deep water or between day and night. C-Vs aggregated in the deep water from October to March and performed DVM in April to June. They were commonly feeding in the deep water between March and June but showed no or very low feeding activity there from July to February. C-Vs in the surface water were commonly feeding and showed the highest proportion of feeding in autumn, when the population in the deep water was inactive. C-V constituted up to nearly 100% of the population biomass, and therefore must be of profound ecological importance. Defined by this dominant role, the population of C. finmarchicus can be characterised as having an active period of feeding, reproduction and development from February to July with a following 6 to 7 months of resting in the deep water, when development is arrested and no feeding occurs. Received: 1 October 1999 / Accepted: 27 April 2000     

三丁基锡对中国近海常见海洋微藻的毒性效应

研究三丁基氯化锡（TBT）对中国近海常见5种硅藻和甲藻（硅藻中丹麦细柱藻（Leptocylindrus danicus）、派格棍形藻（Bacilaria paxillifera）、聚生角毛藻（Chaetoceros socialis）,甲藻中微型原甲藻（Prorocentrum minimum）、简裸甲藻（Gymnodinium simplex））的毒性效应,考察了有机锡对浮游藻光合活性（Fv/Fm）、粒径、生长的影响。结果表明：派格棍形藻、聚生角毛藻、简裸甲藻的光合活性（Fv/Fm）受TBT影响较显著;微型原甲藻、丹麦细柱藻的光合活性受TBT影响较小。高质量浓度TBT胁迫下海洋微藻峰值粒径显著减小,低质量浓度TBT对峰值粒径影响不显著。低质量浓度TBT对派格棍形藻、聚生角毛藻、简裸甲藻、微型原甲藻均有较强的毒性作用,非检测毒性浓度（NDEC）分别为1.17、1.07、0.23、3.73μg.L-1,丹麦细柱藻对TBT具有很强耐受性,NDEC为112.62μg.L-1。     

Perfluorinated compounds in water and sediment from coastal regions of the northern Bohai Sea,China

Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and other perfluorinated compounds (PFCs) were measured in water and sediment from coastal Bohai Bay and surrounding rivers flowing into the bay. Of the 15 PFCs measured, PFOS and PFOA were detected with the greatest frequency. Concentrations in water ranged from<0.2 to 31 ng·L^?1 and<1.0 to 82 ng·L^?1 for PFOS and PFOA, respectively. Concentrations of PFOS and PFOA in sediments ranged from<0.1 to 2.0 ng·g^?1 dw and<0.1 to 0.5 ng·g^?1 dw, respectively. Concentrations of PFCs in Bohai Bay were less than those observed in other areas in Asia, but greater concentrations of ∑PFCs were observed in the Dalin River with concentrations increasing from upstream to downstream, and the greatest concentrations in sediment were observed in tidal flats. The ratio of ∑PFCs in sediment and water indicated that sediment could serve as a significant sink for PFUnA.     

Chronic kidney disease in two coastal districts of Andhra Pradesh, India: role of drinking water

Chronic kidney disease (CKD) has been reported in a few coastal regions of Srikakulam district and Chimakurthy mandal (~30–40 km away from the coast) in the Prakasham district of Andhra Pradesh, India. Some medical experts and the local population have apprehensions that the drinking water is the sole reason for this disease in these areas. As the source of drinking water for these two regions is only groundwater, major ions and trace elements were measured on waters from different sources to identify the causative element(s), if any. Comparison of hydrochemical data of both the areas indicates that groundwater in Srikakulam coastal region is less mineralized than that of the Prakasham region, which may be due to geological, hydrological and climatic reasons. However, the concentrations of various inorganic chemicals are within the permissible limits of drinking water. Hence, for the inorganic chemicals to cause ill health, including CKD, is unlikely or is ruled out in the study areas.     

Metal concentrations in sediment and Nereis diversicolor in two Moroccan lagoons: Khnifiss and Oualidia

Metal concentrations were measured monthly during an annual cycle (December 2004 to January 2006) in the tissues of Nereis diversicolor ragworms and sediment from two Moroccan Atlantic coastal lagoons: Oualidia in the north, situated in a highly industrialised urban area and Khnifiss in the south, far from anthropogenic influences. Relatively high levels of Zn, Ag and Cd were found in the sediment of Oualidia lagoon, while Ni concentrations were shown to be high at Khnifiss. The significant metal levels at Oualidia are a result of industrial and urban discharges, coupled with discharges from adjacent phosphate ore processing plants. Trace metal concentrations in worms vary according to season; they are usually high in winter and spring, in relation to the animal's reproductive cycle. Comparing the two lagoons, trace metal levels appear to be higher in worms from Khnifiss lagoon, suggesting a higher bioavailability of these elements in a relatively pristine area.