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Sample records for vietnam coastal lagoons

  1. Breaching vulnerability of coastal barriers under effects of tropical cyclones : A model study on the Hue lagoon - Vietnam

    NARCIS (Netherlands)

    Tuan, T.Q.; Stive, M.J.F.; Verhagen, H.J.

    2006-01-01

    Under effects of tropical cyclones, the coast is subjected to attack both by surge and wave from the sea and by flooding from the bay. These forces pose a serious breaching threat to natural sea-defence works such as barrier spits, barrier islands, lagoon barriers, etc. on the coast. Unintended

  2. Management of coastal lagoons under climate change

    Science.gov (United States)

    Chapman, Peter M.

    2012-09-01

    Global climate change is a reality that is rendering the concept of 'background conditions' meaningless. We can no longer attempt to maintain the environmental status quo. What we can do is to attempt to maintain ecosystem services despite climate-driven environmental change. There is a pressing need for proactive management that purposefully changes ecosystems to maintain ecosystem services before uncontrolled, detrimental changes occur. Such management would go beyond the bounds of current management efforts and could include, for example, introduction of species, bioengineering, and physical engineering. I suggest that this approach be applied first to coastal lagoons as they are clearly defined geographic areas where this approach can, hopefully, be demonstrated such that it can be applied more widely - when it is accepted, which unfortunately will most probably not occur until the adverse impacts of global climate change become much more apparent.

  3. Lake size and fish diversity in southern Brazil coastal lagoons

    Directory of Open Access Journals (Sweden)

    Lucia Ribeiro Rodrigues

    2015-10-01

    Full Text Available The coastal plain of Rio Grande do Sul, southern Brazil, presents a series of shallow lagoons with diverse size and morphology. The objective of this study is to determine whether the size of the lagoon is an effective factor for structuring fish diversity. In this regard, nine lagoons with distinct areas were sampled: three with an area up to 40 hectares, three with area between 40 and 80 hectares, and three with an area of over 80 hectares. Each lagoon was sampled once on the littoral and pelagic zones. At each point, fish were captured through a set of gill nets with different mesh sizes. Captured specimens were identified, quantified and evaluated for weight and length. A total of 24 fish species belonging to 10 families was obtained, with Characidae presenting the highest species richness. Cyanocharax alburnus was the only species that occurred in all lagoons. Cyphocharax voga, Astyanax eigenmmaniorum, Oligosarcus jenynsii and O. robustus were also frequent species, present in most of the sampled lagoons. Lycengraulis grossidens was captured in just two lagoons with increased conductivity. The community structure showed the highest species richness in lakes with an area over 40 ha, however the highest mean diversity values were observed in ponds up to 40 ha. Cluster Analysis yielded the formation of two groups: a group formed by just one lagoon and a second one cluster grouping all the other lagoons. This pattern may be associated with the presence of Lycengraulis grossidens as a dominant species in this lagoon clustered apart. The results indicate that lagoons with up to 40 ha present greater homogeneity on the species composition and higher average values of diversity; while intermediate ponds (between 40 and 80 ha have lower average diversity for the fish fauna due to increased heterogeneity in species abundance.

  4. Eutrophication Process on Coastal Lagoons of North of Sinaloa, Mexico

    Science.gov (United States)

    Escobedo-Urias, D.; Martinez-Lopez, A.

    2007-05-01

    Coastal ecosystems in the Gulf of California support diverse and important fisheries and are reservoirs of great biological diversity. In northern Sinaloa, population growth and development, as well as increased use of these natural systems for recreation, has substantially increased the pressure placed upon marine resources. Discharge of untreated wastewaters generated by diverse human activities has been notably altered its health and integrity, principally along the lagoon's eastern shore In the late 60s, agriculture moved into a dominant role in coastal northern Sinaloa. The coastal plain encompasses more than 200,000 hectares under cultivation that now introduces large amounts of organic material, pesticides, heavy metals, and fertilizers into the lagoon systems of Topolobampo and San Ignacio-Navachiste-Macapule System at drainage discharge points and a minor grade in Colorado Lagoon. These lagoons are shallow and exhibit low water quality, lost of lagoon depth, presence of toxic substances (heavy metals) near the discharge points of wastewaters, and presence of harmful algal blooms. With the aim of evaluate the nutrients loadings (wastewaters, groundwaters) and their effects on the coastal lagoons of north of Sinaloa, the preliminary analysis of the physical, chemical and biologic variables data series are analyzed. From 1987-2007 eutrophication process is identified in Topolobampo Complex show increase tendency in annual average concentrations of DIN (Dissolved Inorganic Nitrogen= NO2+NO3) from 0.5 μ M in 1987 to 2.7 μ M in 2006. Trophic Index (TRIX) values, low nutrient ratios (N: P and N: Si) and the phytoplanktonic community structure support this result. Preliminary results of nutrients loadings show a mayor contribution of wastewaters into the coastal zone.

  5. Factors Controlling the Morphodynamics of a Tropical Coastal Lagoon.

    Science.gov (United States)

    Enriquez, C.; Marino-Tapia, I.

    2016-02-01

    Celestun is a large (22 km) and elongated (north-south axis) tropical coastal lagoon known for its beauty and biodiversity, but its morphology has been artificially altered by an embankment road built to provide access to the coastal town. This road divided the lagoon by the middle nearly blocking the communication and heavily altering the hydrodynamics. Since then, the head has a restricted circulation (hence higher residence time) and accretion processes have modified the flows affecting the water quality and the tidal flooding towards the wetland and mangrove regions surrounding the lagoon. In this study a morphodynamic process-based numerical model (DELFT3D) is used to investigate the hydro and morphodynamics of Celestun resulting from various meteorological and oceanographic forcings and under different scenarios of anthropogenic alterations (i.e. with and without the road). The coastal lagoon receives important submarine groundwater discharges and therefore the influence of density gradients in the system dynamics is also studied. Results show that the tides control the instantaneous hydrodynamic characteristics but the continental water discharges through SGDs and their variations dominate the morphodynamics in relation to the channel development and evolution. The embankment road restricts the flow to the upper half of the lagoon, minimizing the water circulation at the head, and modifies the circulation patterns creating a large region of accretion in the south near the road.

  6. Intertidal deposits: river mouths, tidal flats, and coastal lagoons

    NARCIS (Netherlands)

    Eisma, D.; Boer, de P.L.; Cadee, G.C.; Dijkema, K.; Ridderinkhof, H.; Phillippart, C.

    1998-01-01

    Intertidal Deposits: River Mouths, Tidal Flats, and Coastal Lagoons combines the authors personal and professional experience with the mass of available literature to present a cohesive overview of intertidal deposits and the widely diverse conditions of their formation worldwide. This includes the

  7. Participation and Sustainable Management of Coastal Lagoon Ecosystems: The Case of the Fosu Lagoon in Ghana

    Directory of Open Access Journals (Sweden)

    Ernest K.A. Afrifa

    2010-01-01

    Full Text Available Participation as a tool has been applied as a social learning process and communication platform to create awareness among stakeholders in the context of resource utilisation. The application of participatory processes to aquatic ecosystem management is attracting a growing body of literature. However, the application of participation as a tool for sustainable management of coastal lagoon ecosystems is recent. This paper examines the context and the extent of participation of stakeholders in the management of the Fosu lagoon in Ghana. Six hundred individuals from twenty seven stakeholder groups were randomly selected for study. Both closed and open-ended questions were used in face-to-face interviews with stakeholders. The findings indicate that the stakeholder groups were not involved in decision-making regarding the conservation of the lagoon irrespective of their expertise in planning and/or their interest in lagoon resource utilisation. This situation has created apathy among some of the stakeholders who feel neglected in the decision-making process. There is scope for broadening the base of interest groups in decision-making processes regarding the lagoon and improving stakeholder participation in the management of the lagoon to ensure the sustainability of the management process.

  8. A mechanistic model of runoff-associated fecal coliform fate and transport through a coastal lagoon.

    Science.gov (United States)

    Steets, B M; Holden, P A

    2003-02-01

    Fecal coliform (FC) contamination in coastal waters is an ongoing public health problem worldwide. Coastal wetlands and lagoons are typically expected to protect coastal waters by attenuating watershed pollutants including FC bacteria. However, new evidence suggests that coastal lagoons or marshes can also be a source of high indicator organism concentrations in coastal waters. We asked for a Mediterranean-type climate, what is the fate of runoff-associated FC through a coastal lagoon? To address this question, we developed a mass balance-based, mechanistic model of FC concentration through a coastal lagoon and simulated, for summer and winter conditions, FC within the lagoon water column, lagoon sediments, and in the ocean water just downstream of the lagoon mouth. Our model accounts for advective flow and dispersion, decay and sedimentation and resuspension of FC-laden sediments during high flow, erosional conditions. Under low flow conditions that occur in the summer, net FC decay and FC storage in lagoon sediments are predicted. Under high flow conditions that occur in the winter, FC-laden sediments are predicted to erode, resuspend and flow out of the lagoon where they elevate FC concentrations in the coastal ocean. For both seasonal conditions, the predicted water column FC concentrations were within an order of magnitude of field measurements for a reference site in southern California. Our results suggest that there are seasonally varying roles for coastal lagoons in mediating FC contamination to coastal waters.

  9. Plankton bioindicators of environmental conditions in coastal lagoons

    Science.gov (United States)

    Hemraj, Deevesh A.; Hossain, Md A.; Ye, Qifeng; Qin, Jian G.; Leterme, Sophie C.

    2017-01-01

    Coastal lagoons are characterised by strong spatial gradient of environmental parameters, especially hypersalinity, and are prone to anthropogenic disturbance. The Coorong (South Australia) is an inverse estuarine coastal lagoon separated from the sea by sand dunes. It is exposed to extreme water quality changes that affect its aquatic communities. Here, we used plankton as indicators of extreme environmental fluctuations to monitor and manage the environmental health of such complex systems. We defined the relationship of different plankton communities with water quality fluctuations and determined plankton species suitable for monitoring the ecosystem health. Two distinct communities of phytoplankton and zooplankton were identified, with salinity and nutrients being the principal factors impacting species distribution. Thus, two sets of indicator species were selected based on the different communities observed. Polychaete and gastropod larvae were positive indicators, showing salinity range restriction of brackish to marine. The distribution Acartia cf. fancetti represented healthy hypersaline conditions (salinity 40-60), while Cyclophora sp. and Scrippsiella sp. were negative indicators, correlating with extreme salinity and ammonia levels. The implementation of planktonic organisms as environmental indicators provided a constructive tool for the management of ecosystem health of the Coorong and will be applicable to similar coastal lagoons.

  10. Seasonal hydrochemical variation in a tropical coastal lagoon (Açu Lagoon, Brazil

    Directory of Open Access Journals (Sweden)

    G. G. Chagas

    Full Text Available Hydrochemical conditions in the Açu Lagoon are described using spatial and temporal variations of various limnological variables (water temperature, dissolved oxygen, electric conductivity, total alkalinity, carbon dioxide, dissolved and total nutrients (N, P and Si, and chlorophyll a. Collected data was used in order to understand the structure and functioning of an enclosed coastal lagoon strongly influenced by climatic conditions. Water samples were collected monthly (November 1999-December 2000 in five sampling stations established along the lagoon. A decreasing spatial gradient of electrical conductivity was observed beginning from a sand bar region between the lagoon and the sea in the direction of the sweet-water input area. The positive correlation observed between the pH and dissolved oxygen (DO values, and the negative one observed between pH values and those of carbon dioxide (CO2, evidenced coupled biological processes, e.g., primary production and decomposition. Both spatial and temporal variation of dissolved nutrients showed fast increase and decrease in the beginning of summer, suggesting that nutrient input resulting from rainfall stimulates phytoplankton production, as reflected by chlorophyll a concentration increase.

  11. Seagrass-sediment feedbacks in shallow coastal lagoons

    Science.gov (United States)

    Carr, J. A.; D'Odorico, P.; McGlathery, K.; Wiberg, P.

    2009-12-01

    Shallow coastal lagoons are environments where a delicate equilibrium exists between water quality and sea grass cover. Seagrass cover limits the resuspension of bed sediments thereby favoring a clearer water column. These conditions allow for the penetration of adequate levels of light, which in turn, is fundamental for the survival of seagrass. It is still unclear what role this positive feedback may play in the dynamics and restoration of seagrass communities. Positive feedbacks are often associated with the existence of bistable dynamics in ecosystems. In this specific case a bare and a fully vegetated sediment bed could be both stable states of the system. This study develops a one dimensional hydrodynamic model of vegetation-sediment-water flow interactions to investigate the strengths of positive feedbacks between sea grass cover, stabilization of bed sediments, turbidity of the water column, and the existence of a favorable light environment for seagrasses. The model is applied to Hog Island Bay, a shallow coastal lagoon on the eastern shore of Virginia. The effects of temperature, eutrophication, and bed grain size on bistability of seagrass ecosystems in the lagoon are explored. The results indicate that under typical conditions, seagrass is stable in water depths sustain seagrass. Decreases in sediment size and increases in water temperature and degree of eutrophication shift the bistable range to shallower depths, with more of the bay bottom unable to sustain seagrass.

  12. Benthic ecology of tropical coastal lagoons: Environmental changes over the last decades in the Términos Lagoon, Mexico

    Science.gov (United States)

    Grenz, Christian; Fichez, Renaud; Silva, Carlos Álvarez; Benítez, Laura Calva; Conan, Pascal; Esparza, Adolfo Contreras Ruiz; Denis, Lionel; Ruiz, Silvia Díaz; Douillet, Pascal; Martinez, Margarita E. Gallegos; Ghiglione, Jean-François; Mendieta, Francisco José Gutiérrez; Origel-Moreno, Montserrat; Garcia, Antonio Zoilo Marquez; Caravaca, Alain Muñoz; Pujo-Pay, Mireille; Alvarado, Rocío Torres; Zavala-Hidalgo, Jorge

    2017-10-01

    The Términos Lagoon is a 2000-km2 wide coastal lagoon linked to the largest river catchment in Mesoamerica. Economic development, together with its ecological importance, led the Mexican government to pronounce the Términos Lagoon and its surrounding wetlands as a Federal protected area for flora and fauna in 1994. It is characterized by small temperature fluctuations, but with two distinct seasons (wet and dry) that control the biological, geochemical, and physical processes and components. This paper presents a review of the available information about the Términos Lagoon. The review shows that the diversity of benthic communities is structured by the balance between marine and riverine inputs and that this structuration strongly influences the benthic metabolism and its coupling with the biogeochemistry of the water column. The paper also presents many specific drivers and recommendations for a long-term environmental survey strategy in the context of the expected Global Change in the Central American region.

  13. Evidence of North Africa’s Green Revolution Preserved in Sedimentary Organic Matter Deposited in Three Coastal Lagoons.

    Science.gov (United States)

    Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropogenic nutrient loading to lagoon food webs are often more pronounced than in other coastal ecosystems. For these reasons, many lagoons also provide an excellent environment for the dep...

  14. Water depth selection, daily feeding routines and diets of waterbirds in coastal lagoons in Ghana

    NARCIS (Netherlands)

    Ntiamoa-Baidu, Y; Piersma, T; Wiersma, P; Poot, M; Battley, P; Gordon, C

    Water depth requirements, diet, feeding styles and diurnal activity patterns are described for waterbirds using two brackish water lagoon systems in coastal Ghana, the Songor and Keta Lagoons, We project the habitat and activity data on a guild structure defined on the basis of individual feeding

  15. Implementation challenges of climate change adaptation initiatives in coastal lagoon communities in the Gulf of Mexico

    National Research Council Canada - National Science Library

    Vázquez, Luz María

    2017-01-01

    This paper explores some key challenges the Mexican government may face when implementing climate change adaptation initiatives in coastal lagoon communities in the Mexican state of Tabasco, in the Gulf of Mexico...

  16. Ecological assessment of a coastal shallow lagoon in Lagos, Nigeria

    African Journals Online (AJOL)

    Michael Horsfall

    western lagoons of Nigeria. The lagoon sediments range between mud, sandy mud, muddy sand, and sand (Ajao and Fagade, 1990). Artisanal fishers within the lagoon mainly exploit the fisheries using wooden/dug-out canoes ranging in size from 3 to 8m long. The canoes are either paddled or powered by small outboard ...

  17. The role of benthic macrophytes and their associated macroinvertebrate community in coastal lagoon resistance to eutrophication.

    Science.gov (United States)

    Lloret, Javier; Marín, Arnaldo

    2009-12-01

    Eutrophication is widely recognised as one of the major menaces to coastal environments, particularly enclosed bays and lagoons. Although there is a general understanding of the consequences of eutrophication in these systems, there is a lack of sufficient knowledge concerning biotic feedbacks that influence eutrophication patterns and the resistance capacity of coastal environments. In this paper, the isotope ratios of main producers and consumers of a Mediterranean lagoon were examined in order to elucidate the fate of anthropogenic inputs from the main watercourse flowing into the lagoon. The results of the study of stable isotope data in the Mar Menor lagoon reflected that the whole benthic community plays an important role as a natural 'filter' that removes excess nutrients from the water column and stores them in the sediments, thereby enhancing lagoon resistance to eutrophication.

  18. Stage-specific distribution models can predict eel (Anguilla anguilla) occurrence during settlement in coastal lagoons

    Science.gov (United States)

    Leone, C.; Zucchetta, M.; Capoccioni, F.; Gravina, M. F.; Franzoi, P.; Ciccotti, E.

    2016-03-01

    Eel (Anguilla anguilla) is a catadromous fish species typical of Mediterranean coastal lagoons, that currently suffers from several anthropogenic and natural impacts. These are thought to be the cause of a stock-wide decline that this panmictic species is facing, in inland and coastal waters of Europe and North Africa. The decline affects both adult phases and recruitment, i.e. glass eel arrival to coastal waters and their ascent to inland waters. Quantitative features of eel recruitment reflect a transoceanic global scale, but also depend on local environmental conditions, the latter also affecting settlement dynamics in transitional waters. There is only little information on the dynamics of these two processes in coastal lagoons, notwithstanding the paramount importance of both in sustaining local stocks abundance and their demographic structure for this typical but also economically important inhabitant of Mediterranean lagoons, habitats that constitute an important share of the eel distribution area. The present study aims, therefore, to clarify space and time dynamics of local scale recruitment and of settlement in a coastal lagoon in the Mediterranean area, also by setting up a specific methodological approach. For this purpose, data from field surveys in combination with Species Distribution Models (SDMs) have been used in order to relate distribution of eel juvenile stages to the environmental conditions within the lagoon. Specifically, models were calibrated to quantify the relationship between presence of juvenile eel and the main environmental drivers, with the aim of identifying potential habitats for eel settlement within the lagoon. Results gained by modelling suggest certain spatial and temporal colonization patterns for the juvenile eel in the Fogliano lagoon, a typical Mediterranean coastal lake. The modelling approach has therefore proved to be a useful tool for predicting habitats for eel recruitment at the local scale and settlement, because

  19. Hydrogeologic controls on chemical transport at Malibu Lagoon, CA: Implications for land to sea exchange in coastal lagoon systems

    Directory of Open Access Journals (Sweden)

    N. Dimova

    2017-06-01

    New hydrological insights for the region: Nearshore lagoons that are seasonally disconnected from the coastal ocean occupy about 10% of coastal areas worldwide. Lagoon systems often are poorly flushed and thus sensitive to nutrient over-enrichment that can lead to eutrophication, oxygen depletion, and/or pervasive algal blooms. This sensitivity is exacerbated in lagoons that are intermittently closed to surface water exchange with the sea and occur in populous coastal areas. Such estuarine systems are disconnected from the sea during most of the year by wave-built barriers, but during the rainy season these berms can breach, enabling direct water exchange. Using naturally-occurring 222Rn as groundwater tracer, we estimate that groundwater discharge to Malibu Lagoon during open berm conditions was one order of magnitude higher (21 ± 17 cm/day than during closed berm conditions (1.8 ± 1.4 cm/day. The SGD (submarine groundwater discharge into nearshore coastal waters at the SurferRider and Colony Malibu was 4.2 cm/day on average. The exported total dissolved nitrogen (TDN through the berm during closed berm was 1.6 × 10−3 mol/day, whereas during open berm (exported by the Creek was 3.5 × 103 mol/day. Although these evaluations are specific to the collection campaigns the 2009 and 2010 hydro years, these two distinct hydrologic scenarios play an important role in the seasonality and geochemical impact of land/sea exchange, and highlight the sensitivity of such systems to future impacts such as sea level rise and increasing coastal populations.

  20. Project Hue: Report and field study on the water related problems and solutions in and around the Cau Hai lagoon and the Tu Hien inlet, Vietnam

    NARCIS (Netherlands)

    Peters, T.; Jongerius, Y.R.; Franken, J.T.; Ponsioen, L.A.; Tieleman, O.C.

    2015-01-01

    The Tam Giang-Cau Hai lagoon system, lying in the Thua Thien-Hue province in central Vietnam, is affected by a tropical monsoon climate. This among others is the reason the Cau Hai Lagoon area has a long history of floods and other water related problems. Inhabitants are very dependent on the

  1. Freshwater inflows and seasonal forcing strongly influence macrofaunal assemblages in Mediterranean coastal lagoons

    Science.gov (United States)

    Prado, Patricia; Caiola, Nuno; Ibáñez, Carles

    2014-06-01

    Coastal lagoons of the Ebro Delta (Catalonia, Spain) are part of the Ebro Delta Natural Park managed by regional government authorities. Coastal lagoons have persistently received freshwater inputs from the Ebro River from May to November that have altered their natural ecology and hydrological cycle. In this study, we evaluate the seasonal effect of contrasting salinity regimes (polyhaline in the Tancada lagoon, mesohaline in the Encanyissada and oligohaline in the Clot lagoon) on the composition, abundance, species richness, alpha diversity and biomass of benthic macrofauna communities, and we assess the relative contribution of local environmental variables to the observed patterns. Additional sampling was conducted in the largest lagoon (Encanyissada) in order to assess variability at lower spatial scale. At both spatial scales (i.e., among-lagoon and within-lagoon), species richness and diversity tended to increase at higher salinities, particularly in summer. At the assemblage level, significantly different groupings were also found among lagoons and among zones of the Encanyissada lagoon, with more distinctive differences also in summer. Environmental factors accounted for up to 56-60% of the variation in macrofaunal assemblages at both spatial scales, with salinity and temperature accounting for the largest contributions (approx. 14% and 10%, respectively), whereas biomass was mostly controlled by temperature and nutrients. Distinctive oxygen and organic matter levels across the lagoons were also associated with the freshwater influx and displayed significant contributions to observed patterns. Our study shows that the low salinity regime and/or other factors related to long-term inputs of freshwater shape the community of macrofauna within the lagoons, a central trophic resource for most of the local species of fish and aquatic birds. Restoration of these systems to their natural hydrological functioning without further inputs of freshwater and higher

  2. Distributions of phytoplankton in a coastal lagoon of Mahin, Ondo ...

    African Journals Online (AJOL)

    Distributions of phytoplankton were investigated in Mahin Lagoon within Transgressive mud coast of Ondo, Western Nigeria. Collections and analyses of samples of phytoplankton and surface waters (for some physico-chemical parameters) were done at fifteen stations along the stretch of the lagoon in October 2013 and ...

  3. Heavy metals in a latin american coastal lagoon - sediments, water and macrophytes

    OpenAIRE

    Ambrozic, Nada

    2015-01-01

    Dissertação de mestrado, Ecohidrologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015 Coastal lagoons are considered to be some of the most productive ecosystems on Earth, providing a wide range of ecosystem services and resources. Jacunem lagoon, ES, Brazil, was studied to evaluate the impact of anthropogenic activities on heavy metal concentrations in sediments, water and macrophytes (Eichhornia crassipes and Typha domingensis). In order to verify the presence of heav...

  4. Spatial and temporal variation of water quality in the coastal lagoons of Sinaloa

    Science.gov (United States)

    Paez-Osuna, F.; Lopez-Aguiar, L. K.; Del Río-Chuljak, A.; Ruiz-Fernandez, A. C.

    2007-05-01

    The Mexican state of Sinaloa has 656 km of coastline and 221,600 ha of coastal lagoons, and is characterized by a high fishing and agriculture activity. It is well known that agricultural activities constitute a major factor affecting the water quality in the coastal waters. The current study focused on the 6 more important coastal lagoons of Sinaloa (Topolobampo-Ohuira-Santa María, Navachiste-San Ignacio-Macapule, Santa María-La Reforma, Altata-Ensenada del Pabellón, Ceuta and Teacapán-Agua Brava) with the aim to evaluate the water quality spatial and temporal variation at the lagoons (physico-chemical parameters, nutrients (N, P and Si), dissolved oxygen, total suspended solids and chlorophyll a) and to assess its eutrophication status. The water samples were collected in several stations at each lagoon (between 9 and 23 stations depending on the lagoon area) at low and high tides, during three different weather periods (dry-warm, rainy and dry-cold seasons) between May 2004 and April 2005. Mean concentrations of nutrients (μM), dissolved oxygen (mg/L) and chlorophyll a (mg/m3) obtained for each variable were comparable between lagoons (total N=51±45; total P= 2.5±1.5; Si=23±31; DO=6.7±1.8; Chll=1.7±1.9) although seasonal and spatial differences were observed at each lagoon. The nutrient concentrations measured fell in the typical concentration intervals for coastal lagoons; however, critical sampling points were identified and related to direct discharges of untreated effluents from municipal wastes, aquaculture farms and agriculture drain ditches.

  5. Phytoplankton community dynamics in an intermittently open hypereutrophic coastal lagoon in southern Portugal

    Science.gov (United States)

    Coelho, Susana; Pérez-Ruzafa, Angel; Gamito, Sofia

    2015-12-01

    Phytoplankton community' dynamics were studied in Salgados coastal lagoon in order to evaluate the effects of excessive organic loads and also physical stress caused by the irregular opening of the lagoon. Salgados is a hypereutrophic intermittently open coastal lagoon, which received freshwater inputs from small rivers and from a wastewater treatment plant. Cyanophyceae dominated the phytoplankton communities most of the time; Bacillariophyceae became the main taxonomic group in winter when the lagoon was closed; Chlorophyceae was the major class in early summer; pico-nano flagellate algae accounted for a high percentage of total phytoplankton during spring. Potentially harmful taxa were observed during most of the sampling periods, forming blooms and accounting for a considerable percentage of total phytoplankton abundance. A strong differentiation among dry and wet seasons could be noticed. The dry season was dominated by Microsystis aeruginosa, Rhodomonas sp., pico-nano flagellate algae, Cyclotella spp. and Planktothrix sp., while the wet season, although still with the presence of Microsystis aeruginosa, was dominated by Dolichospermum spiroides. The best environmental variables explaining stations patterns and based on phytoplankton taxa were days of isolation, pH, and salinity. Temperature, cumulative rain and total phosphorus were also related with species and stations patterns. The high nutrient load in Salgados lagoon promoted the development and persistence of harmful algae blooms. Proper management of coastal lagoons involves not only the control of direct discharges of nutrients, but also of other factors, including water level and communication with the sea.

  6. Controls of Sediment Nitrogen Dynamics in Tropical Coastal Lagoons.

    Directory of Open Access Journals (Sweden)

    Alex Enrich-Prast

    Full Text Available Sediment denitrification rates seem to be lower in tropical environments than in temperate environments. Using the isotope pairing technique, we measured actual denitrification rates in the sediment of tropical coastal lagoons. To explain the low denitrification rates observed at all study sites (<5 μmol N2 m-2 h-1, we also evaluated potential oxygen (O2 consumption, potential nitrification, potential denitrification, potential anammox, and estimated dissimilatory nitrate (NO3- reduction to ammonium (NH4+; DNRA in the sediment. 15NO3- and 15NH4+ conversion was measured in oxic and anoxic slurries from the sediment surface. Sediment potential O2 consumption was used as a proxy for overall mineralization activity. Actual denitrification rates and different potential nitrogen (N oxidation and reduction processes were significantly correlated with potential O2 consumption. The contribution of potential nitrification to total O2 consumption decreased from contributing 9% at sites with the lowest sediment mineralization rates to less than 0.1% at sites with the highest rates. NO3- reduction switched completely from potential denitrification to estimated DNRA. Ammonium oxidation and nitrite (NO2- reduction by potential anammox contributed up to 3% in sediments with the lowest sediment mineralization rates. The majority of these patterns could be explained by variations in the microbial environments from stable and largely oxic conditions at low sediment mineralization sites to more variable conditions and the prevalences of anaerobic microorganisms at high sediment mineralization sites. Furthermore, the presence of algal and microbial mats on the sediment had a significant effect on all studied processes. We propose a theoretical model based on low and high sediment mineralization rates to explain the growth, activity, and distribution of microorganisms carrying out denitrification and DNRA in sediments that can explain the dominance or coexistence of

  7. Multi-annual and seasonal patterns of waterbird assemblages in a Mediterranean coastal lagoon (El Mellah lagoon of Northeastern Algeria

    Directory of Open Access Journals (Sweden)

    Telailia Salah

    2017-06-01

    Full Text Available Recently, Mediterranean coastal lagoons have raised considerable environmental concerns. Long-term studies of seasonal changes in waterbird assemblages are therefore extremely important in terms of ecological relevance and conservation of these sensitive ecosystems. An ornithological survey of four years was carried out in a typical costal wetland (El Mellah lagoon of Northeastern Algeria. Intra-seasonal comparison of waterbird assemblages (diversity indices demonstrates clear changes between the wintering and the breeding periods. It seems that the first one was rich in term of species number than the second season (43 against 24. In contrast, the breeding seasons were more equilibrate (high values of Simpson, Shannon and evenness index. Additionally, curves in the diversity/dominance diagram revealed that both wintering and breeding assemblages share the same characteristics of community structure, few dominant species (with intermediate relative abundance and many rare species with the relative abundance lower than 0.1. Invertebrates (25 species and piscivorous (11 species are the most abundant guilds over the four years of study (no significant differences among years have been calculated. The marked decline in bird species diversity recorded in this study (in comparison with previous studies is mainly due to salinity oscillations (due to aquaculture activities and may be of concern to wetland managers and it might be useful to provide some guidelines about the characteristics that coastal lagoons have to follow in the construction process to enhance the biodiversity.

  8. Nutrient fluxes and net metabolism in a coastal lagoon SW peninsula of Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Cervantes Duarte, R.

    2016-09-01

    Full Text Available Fluxes of nutrients and net metabolism were estimated in coastal lagoon Magdalena Bay using LOICZ biogeochemical model. In situ data were obtained from 14 sites in the lagoon and also from a fixed site in the adjacent ocean area. Intense upwelling (February to July and faint upwelling (August to January were analyzed from monthly time series. The Temperature, nitrite + nitrate, ammonium and phosphate within the lagoon showed significant differences (p<0.05 between the two periods. Salinity (p=0.408 was more homogeneous (no significantly different due to mixing processes. During the intense upwelling period, nutrients increased in and out of the lagoon due to the influence of Transitional Water and Subartic Water transported by the California Current. However, during the faint upwelling, from August to January, the Transition Water and Subtropical Surface Water were predominant. Magdalena Bay showed denitrification processes of throughout the year as it occurred in other semi-arid coastal lagoons. It also showed a net autotrophic metabolism during intense upwelling and heterotrophic metabolism during faint upwelling. Understanding nutrient flows and net metabolism through simple biogeochemical models can provide tools for better management of the coastal zone.

  9. Zooplankton of an urban coastal lagoon: composition and association with environmental factors and summer fish kill

    Directory of Open Access Journals (Sweden)

    Leonardo C. e Souza

    2011-06-01

    Full Text Available Zooplankton may be regarded as a sensitive tool for monitoring environmental variations in coastal lagoons due to their ability to immediately react to changes in the water column trophic features and salinity levels. As a coastal lagoon with a broad history of anthropic influence, Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil is widely used for water sports and artisanal fishing. The present study aimed to expand the knowledge base about zooplankton in the Rodrigo de Freitas Lagoon by assessing the composition and time-spatial distribution of the major zooplankton groups. Samples were collected fortnightly from at four distinct sampling points August 2001 to July 2002. At each point, salinity, temperature, dissolved oxygen and water transparency were measured. During the study period, the lagoon behaved as an spatially homogeneous environment in what regards the abiotic variables. However, all these variables showed significant differences along the time, mainly related to seasonality (air temperature and rainy and dry periods. The zooplankton community showed low taxonomic richness, with the predominance of species commonly found in coastal lagoons, especially with mesohaline conditions, as well as those found in estuaries. An interesting fact was the rise in zooplankton abundance at all sampling points right after a fish kill event. Such increase was caused mainly by the Brachionus plicatilis O.F. Müller 1786 species. Thus, the zooplankton community was affected by physical and chemical factors, mainly by the dissolved oxygen decline event and variations in the influx of seawater into the lagoon. In addition, phytoplankton availability and fish predation pressure were suggested as important regulating factors of the zooplankton community.

  10. Strategies of bioremediation of a contaminated coastal Ecosystem (Bolmon Lagoon, South-Easter Mediterranean Coast)

    Energy Technology Data Exchange (ETDEWEB)

    Charpy-Roubaud, C.; Fayolle, S.; Franquet, E.; Pietri, L.; Anselmet, F.; Brun, L.; Roux, B.

    2009-07-01

    Bolmon ecosystem (Bouches du Rhone, South-easter France) is a coastal mediterranean lagoon. This ecosystem presents a great interest in terms of ecology, economy and cultural aspects. Bomon is connected to the salty Berre pond, itself connected to Mediterranean sea, via tiny artificial channels and a main one (rove channel) that also bounds it to the South. (Author)

  11. Pan-European management of coastal lagoons: A science-policy-stakeholder interface perspective

    Science.gov (United States)

    Lillebø, Ana I.; Stålnacke, Per; Gooch, Geoffrey D.; Krysanova, Valentina; Bielecka, Małgorzata

    2017-11-01

    The main objective of the work carried out in the scope of a three years collaborative research project was to develop science-based strategies and a decision support framework for the integrated management of coastal lagoons and their catchments and, in this context, to enhance connectivity between research and policymaking. In this paper our main objective is to share the lessons learned from the innovative methodology used throughout the project. To achieve the proposed objectives, the multidisciplinary scientific knowledge in the project team was combined and integrated with the knowledge and views of local stakeholders of four selected European coastal lagoons, using a three step participatory approach. With this innovative approach, which included the usage of eco-hydrological and water quality-modelling tools, the team developed and analyzed integrated scenarios of possible economic development and environmental impacts in four European lagoons and their catchments. These scenarios were presented and discussed with stakeholders, giving rise to management recommendations for each case study lagoon. Results show that some management options might be transferrable to other European lagoons having similar climatic, geophysical and socio-economic settings. In management terms, the project output provides a set of policy guidelines derived from the different analyses conducted and proposes initiatives concerning management implementation in a local-regional-national-European setting.

  12. Spatial Variation in Development of Epibenthic Assemblages in a Coastal Lagoon

    Science.gov (United States)

    Benedetti-Cecchi, L.; Rindi, F.; Bertocci, I.; Bulleri, F.; Cinelli, F.

    2001-05-01

    Spatial and temporal patterns in colonization of epibenthic assemblages were measured in a coastal lagoon on the west coast of Italy using recruitment panels. It was proposed that if the ecological processes influencing development of assemblages were homogeneous within the lagoon, then there should be no differences in mean cover of colonists nor in spatial patterns of variance in abundance in different areas of the lagoon. In contrast, heterogeneity in ecological processes affecting development would be revealed by spatial variability in colonization. To test these hypotheses, two sticks each with five replicate panels were placed 3-5 m apart in each of two sites 30-100 m apart in each of three locations 500-100 m apart; the experiment was repeated three times between April and December 1999, using new sites at each location each time. The results revealed considerable spatial variation in the structure of developing assemblages across locations. There were significant Location or Time×Location effects in the mean abundance of common taxa, such as Enteromorpha intestinalis , Ulva rigida, Cladophora spp., bryozoans and serpulids. Patterns in spatial variation differed among locations for these organisms. Collectively, the results supported a model of spatial heterogeneity in intensity of processes influencing patterns of recruitment and development of epibenthic assemblages in the Lagoon of Orbetello. The implications of these results for management of environmental problems in complex, variable habitats such as coastal lagoons, are discussed.

  13. Impact of mussel bioengineering on fine-grained sediment dynamics in a coastal lagoon: a numerical modelling investigation

    DEFF Research Database (Denmark)

    Forsberg, Pernille Louise; Lumborg, Ulrik; Bundgaard, Klavs

    2017-01-01

    Rødsand lagoon in southeast Denmark is a non-tidal coastal lagoon. It is home to a wide range of marine flora and fauna and part of the Natura 2000 network. An increase in turbidity through elevated levels of suspended sediment concentration (SSC) within the lagoon may affect the ecosystem health...... due to reduced light penetration. Increasing SSC levels within Rødsand lagoon could be caused by increasing storm intensity or by a sediment spill from dredging activities west of the lagoon in relation to the planned construction of the Fehmarnbelt fixed link between Denmark and Germany. The aim...... of the study was to investigate the impact of a mussel reef on sediment import and SSC in a semi-enclosed lagoon through the development of a bioengineering modelling application that makes it possible to include the filtrating effect of mussels in a numerical model of the lagoonal system. The numerical...

  14. Methane fluxes from tropical coastal lagoons surrounded by mangroves, Yucatán, Mexico

    Science.gov (United States)

    Chuang, P.-C.; Young, M. B.; Dale, A. W.; Miller, L. G.; Herrera-Silveira, J. A.; Paytan, A.

    2017-05-01

    Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m-2 d-1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

  15. Seagrasses and sediment response to the changing physical forcing in a coastal lagoon

    Science.gov (United States)

    Figueiredo da Silva, J.; Duck, R. W.; Pereira, M. J.; Catarino, J. B.

    2003-04-01

    The Ria de Aveiro is an estuary - coastal lagoon system connected to the Atlantic Ocean by a channel with a cross-sectional area that has steadily increased over more than one century. Local ocean tides, with amplitudes of 1-3 m, are today transmitted to the lagoon by the single, engineered inlet channel and propagate to the end of the lagoon channels as a damped progressive wave. The natural channel connecting the lagoon to the ocean evolved during historical times, moving southward and reducing its cross-section. The natural evolution was reverted in 1808 by opening the new inlet channel that has since been protected by breakwaters and deepened by dredging. This controlled evolution has caused an increase in the tidal prism associated with a larger tidal oscillation inside the lagoon. The change in tidal amplitude has important effects on the lagoon ecosystem, which are related to the increase in tidal currents, water level and salinity of the water. The pollution load reaching the lagoon from its catchment area is now, however, more readily flushed to the ocean. Most affected by the change are mudflat and intertidal areas, including the old salt-pans, some showing signs of erosion while others accumulate sediment that is transported in suspension by the strong tidal currents. Important indicators of ecosystem change are the seagrass beds. Until 1980 large areas of the lagoon bed were covered by seagrasses (Zostera, Ruppia, Potamogeton), which were collected in large quantities for use in agriculture. After 1980, the collection declined and the seagrass beds became sediment-covered. This resulted in a large decrease in the area of seagrasses in spite of the decline in the quantity collected. Our results show a pattern in the change of the seagrass populations that can be related to the changes in the physical forcing associated with tidal wave propagation. A parallel change in sediment texture was also observed.

  16. Groundwater dependence of coastal lagoons: The case of La Pletera salt marshes (NE Catalonia)

    Science.gov (United States)

    Menció, A.; Casamitjana, X.; Mas-Pla, J.; Coll, N.; Compte, J.; Martinoy, M.; Pascual, J.; Quintana, X. D.

    2017-09-01

    Coastal wetlands are among the most productive ecosystems of the world, playing an important role in coastal defense and wildlife conservation. These ecosystems, however, are usually affected by human activities, which may cause a loss and degradation of their ecological status, a decline of their biodiversity, an alteration of their ecological functioning, and a limitation of their ecosystem services. La Pletera salt marshes (NE Spain) are located in a region mainly dominated by agriculture and tourism activities. Part of these wetlands and lagoons has been affected by an incomplete construction of an urban development and in this moment is the focus of a Life+ project, whose aim is to restore this protected area. Several studies have analyzed the role of hydrological regime in nutrients, phytoplankton and zooplankton in this area, however, the role of groundwater was never considered as a relevant factor in the lagoon dynamics, and its influence is still unknown. In this study, the hydrogeological dynamics in La Pletera salt marshes has been analyzed, as a basis to set sustainable management guidelines for this area. In order to determine their dependence on groundwater resources, monthly hydrochemical (with major ions and nutrients) and isotopic (δ18OH2O and δD) campaigns have been conducted, from November 2014 to October 2015. In particular, groundwater from six wells, surface water from two nearby streams and three permanent lagoons, and sea water was considered in these surveys. Taking into account the meteorological data and the water levels in the lagoons, the General Lake Model has been conducted to determine, not only evaporation and rainfall occurring in the lagoons, but also the total inflows and outflows. In addition, the Gonfiantini isotopic model, together with equilibrium chemical-speciation/mass transfer models, has been used to analyze the evaporation and the physicochemical processes affecting the lagoons. Results show that during the dry

  17. Nutrient dynamics in tropical rivers, estuarine-lagoons, and coastal ecosystems along the eastern Hainan Island

    Science.gov (United States)

    Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

    2013-06-01

    Nutrient dynamics were studied along the eastern Hainan Island based on field observations during 2006-2009, to understand nutrient biogeochemical processes and to have an overview of human perturbations on coastal ecosystems in this tropical region. The concentrations of nutrients in the rivers had seasonal variations enriched with dissolved inorganic nitrogen (DIN). High riverine concentrations of nitrate were mainly originated from agricultural fertilizer input. The ratios of DIN : PO43- ranged from 37 to 1063, suggesting preferential PO43- relative to nitrogen in the rivers. The areal yields of dissolved silicate (DSi) varied from 76 to 448 × 103 mol km-2 yr-1 due to erosion over the drainage area, inducing high levels of DSi among worldwide tropical systems. Aquaculture ponds contained high concentrations of NH4+ (up to 157 μM) and DON (up to 130 μM). Particulate phosphorus concentrations (0.5 ∼1.4 μM) were in lower level comparied with estuaries around the world. Particulate silicate levels in rivers and lagoons were lower than global average level. Nutrient biogeochemistry in coastal areas were affected by human activities (e.g. aquaculture, agriculture), as well as natural events such as typhoon. Nutrient concentrations were low because open sea water dispersed land-derived nutrients. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes would be magnified by estuarine processes (e.g. regeneration, desorption) in the Wenchanghe/Wenjiaohe Estuary, Wanquan River estuary, and the Laoyehai Lagoon except in the Xiaohai Lagoon. Riverine and groundwater input were the major sources of nutrients to the Xiaohai Lagoon and the Laiyehai Lagoon, respectively. Riverine input and aquaculture effluent were the major sources of nutrients to the eastern coastal of Hainan Island. Nutrient inputs to the coastal ecosystem can be increased by typhoon-induced runoff of rainwater, and phytoplankton bloom in the sea would be

  18. Morphodynamics of seasonally closed coastal inlets at the central coast of Vietnam

    NARCIS (Netherlands)

    Tran, T.T.

    2011-01-01

    Situated in a monsoon-prone humid tropical region, Vietnam is affected by both oceanic and continental climates causing disasters to the country like riverine flooding and storm induced damage. The coastal districts of Vietnam have a population of about 18 million habitants, account for nearly one

  19. Ecosystem response to human- and climate-induced environmental stress on an anoxic coastal lagoon (Etoliko, Greece) since 1930 AD

    NARCIS (Netherlands)

    Koutsodendris, Andreas; Brauer, Achim; Zacharias, Ierotheos; Putyrskaya, Victoria; Klemt, Eckehard; Sangiorgi, Francesca; Pross, Jörg

    To better constrain the effects of anthropogenic impact on coastal wetlands with respect to natural variability, we here analyze annually laminated sediments from Etoliko lagoon (western Greece, Mediterranean Sea) spanning the last*80 years. Subdecadal- scale palynomorph (pollen and dinoflagellate

  20. Landscape changes in a coastal system undergoing tourism development: implications for Barra de Navidad Lagoon, Jalisco, Mexico

    National Research Council Canada - National Science Library

    Tara L. Holland; José Mariscal Romero; Robin Davidson-Arnott; Jeffrey Cardille

    2012-01-01

    In this study, changes in land cover and land use patterns that occurred between 1985 and 2000 in the surrounding basin of the Barra de Navidad coastal lagoon in Jalisco, Mexico are quantified and explained...

  1. Hatching rhythms and dispersion of decapod crustacean larvae in a brackish coastal lagoon in Argentina

    Science.gov (United States)

    Anger, K.; Spivak, E.; Bas, C.; Ismael, D.; Luppi, T.

    1994-12-01

    Mar Chiquita, a brackish coastal lagoon in central Argentina, is inhabited by dense populations of two intertidal grapsid crab species, Cyrtograpsus angulatus and Chasmagnathus granulata. During a preliminary one-year study and a subsequent intensive sampling programme (November December 1992), the physical properties and the occurrence of decapod crustacean larvae in the surface water of the lagoon were investigated. The lagoon is characterized by highly variable physical conditions, with oligohaline waters frequently predominating over extended periods. The adjacent coastal waters show a complex pattern of semidiurnal tides that often do not influence the lagoon, due to the existence of a sandbar across its entrance. Besides frequently occurring larvae (exclusively freshly hatched zoeae and a few megalopae) of the two dominating crab species, those of three other brachyurans ( Plathyxanthus crenulatus, Uca uruguayensis, Pinnixa patagonica) and of one anomuran (the porcellanid Pachycheles haigae) were also found occasionally. Caridean shrimp ( Palaemonetes argentinus) larvae occurred in a moderate number of samples, with a maximum density of 800·m-3. The highest larval abundance was recorded in C. angulatus, with almost 8000°m-3. Significantly more C. angulatus and C. granulata zoeae occurred at night than during daylight conditions, and more larvae (statistically significant only in the former species) during ebb (outflowing) than during flood (inflowing) tides. In consequence, most crab zoeae were observed during nocturnal ebb, the least with diurnal flood tides. Our data suggest that crab larvae do not develop in the lagoon, where the adult populations live, but exhibit an export strategy, probably based upon exogenously coordinated egg hatching rhythms. Zoeal development must take place in coastal marine waters, from where the megalopa eventually returns for settlement and metamorphosis in the lagoon. Significantly higher larval frequency of C. granulata in

  2. Macroalgal blooms in coastal lagoons of the Gulf of California eco-region: a summary of current knowledge

    OpenAIRE

    Piñón-Gimate, Alejandra; Páez-Osuna, Federico; Serviere-Zaragoza, Elisa; Casas Valdéz, Margarita

    2012-01-01

    The Gulf of California is an important eco-region with 52 coastal lagoons that are affected by the different anthropogenic activities in their surrounding areas. Several studies in the region have reported seasonal changes in macroalgal biomass, and some have suggested that these changes may be associated with nutrient enrichment. However, research on macroalgal biomass increase has been done in only 27% of these coastal lagoons. In some species, biomass is related to high concentrations of n...

  3. Heterotrophic microbial activity and organic matter degradation in coastal lagoons of Colombia.

    Science.gov (United States)

    Gocke, Klaus; Mancera Pineda, José Ernesto; Vallejo, Adriana

    2003-03-01

    In this study we measured the community respiration and the bacterial respiration as part of the overall degradation process of organic material. Additionally, the turnover rates of the pools of dissolved free glucose and acetate as representatives of the fraction of easily degradable low molecular organic solutes were determined. The study was performed in several coastal lagoons of the "Outer Delta of the Río Magdalena" in northern Colombia. The lagoons can be separated into two groups: The first group contains highly productive brackish lagoons with chl a concentrations ranging from 62-130 micrograms/l. The second group consists of less productive freshwater lagoons with chl a between 5.5-19 micrograms/l. Turnover rates of glucose and acetate were very fast in the highly productive lagoons resulting in turnover times of less than 20 min for both compounds. In the less productive systems the cycling of glucose and acetate was much slower. Here the mean values of the turnover times were 2 hr for glucose and 1.5 hr for acetate. The rates of bacterial DNA-formation measured as thymidine incorporation differed significantly between both groups of lagoons, being very high (1.86-2.76 nmol/l/hr) in the highly productive and relatively low (0.073-0.55 nmol/l/hr) in the less productive group. Water column community respiration ranged between 122 and 16 micrograms C/l/hr with means of 88 micrograms C/l/hr in the highly and 19 micrograms C/l/hr in the less productive group. In the first group the mean values of the bacterial contribution to community respiration amounted to 37% and in the second group to 18%. The bacterial respiration was determined in an indirect way via bacterial biomass production and assuming a growth efficiency of 50%. It is discussed whether this relatively high growth efficiency allows reasonable results in both groups of lagoons.

  4. Seagrasses and sediment response to changing physical forcing in a coastal lagoon

    Science.gov (United States)

    Figueiredo da Silva, J.; Duck, R. W.; Catarino, J. B.

    The Ria de Aveiro is an estuary-coastal lagoon system connected to the Atlantic Ocean by a channel with a cross-sectional area that, for more than a century, has increased steadily, partly because of dredging over the last 50 years. Local ocean tides, with amplitudes of up to 3 m, are today transmitted to the lagoon by the single, engineered inlet channel and propagate to the end of the lagoon channels as a damped progressive wave. The increase in tidal amplitude with time has affected the lagoon ecosystem and the water has become more saline. Seagrass beds are important indicators of ecosystem change; until 1980, much of the lagoon bed was covered by seagrasses (Zostera, Ruppia, Potamogeton), which were collected in large quantities for use in agriculture. After 1960, the harvesting declined and the seagrass beds became covered in sediment, so that the area of seagrasses decreased substantially despite the decline in the quantity collected. The change in the pattern of seagrass populations can be related to changes in the physical forcing associated with increased tidal wave penetration. This has, in turn, induced transport and redistribution of coarser, sandy sediment and increased re-suspension and turbidity in the water column. However, the initiating cause for this ecosystem change was dredging, which, since the 1950s, has been used increasingly to widen and deepen the channels of the system.

  5. Seagrasses and sediment response to changing physical forcing in a coastal lagoon

    Directory of Open Access Journals (Sweden)

    J. Figueiredo da Silva

    2004-01-01

    Full Text Available The Ria de Aveiro is an estuary–coastal lagoon system connected to the Atlantic Ocean by a channel with a cross-sectional area that, for more than a century, has increased steadily, partly because of dredging over the last 50 years. Local ocean tides, with amplitudes of up to 3 m, are today transmitted to the lagoon by the single, engineered inlet channel and propagate to the end of the lagoon channels as a damped progressive wave. The increase in tidal amplitude with time has affected the lagoon ecosystem and the water has become more saline. Seagrass beds are important indicators of ecosystem change; until 1980, much of the lagoon bed was covered by seagrasses (Zostera, Ruppia, Potamogeton, which were collected in large quantities for use in agriculture. After 1960, the harvesting declined and the seagrass beds became covered in sediment, so that the area of seagrasses decreased substantially despite the decline in the quantity collected. The change in the pattern of seagrass populations can be related to changes in the physical forcing associated with increased tidal wave penetration. This has, in turn, induced transport and redistribution of coarser, sandy sediment and increased re-suspension and turbidity in the water column. However, the initiating cause for this ecosystem change was dredging, which, since the 1950s, has been used increasingly to widen and deepen the channels of the system.

  6. Evidence of North Africa's green revolution preserved in sedimentary organic matter deposited in three coastal lagoons.

    Science.gov (United States)

    Oczkowski, Autumn J; Flower, Roger J; Thompson, Julian R; Ayache, Fethi; Ahmed, Mahmoud H; Ramdani, Mohamed; Turner, Simon

    2011-07-01

    Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropogenic nutrient loading to lagoon food webs are often more pronounced than in other coastal ecosystems. For these reasons, many lagoons also provide an excellent environment for the deposition and accumulation of organic matter (OM). Sediment cores were retrieved from three North African lagoons to provide records of recent environmental changes. We measured percentage nitrogen (%N), nitrogen stable isotope values (delta15N), and percentage organic matter (%OM), and we used radiometric dating techniques (210Pb, 137Cs) to examine the evidence for the intensification of upstream agricultural practices in sediment cores from Lake Manzala (Egypt), Ghar El Melh Lagoon (Tunisia), and Lagune de Nador (Morocco). With the exception of one core collected near a sewage outfall, sediments from Lake Manzala clearly reflected the impact of agricultural intensification following completion of the Aswan High Dam and delta barrages in the mid-1960s to early 1970s. Both %N and %OM more than doubled in three Manzala sediment cores, and delta15N values declined from 5 per thousand to agricultural fertilizer use. Lagune de Nador receives relatively little agricultural drainage water, and core data did not show the same trends as Manzala and Ghar El Melh. Overall, the sediment core data from these systems reflect environmental shifts in the quantity, quality, and isotope signature of the deposited organic matter and confirm the concerns of local scientists and environmental managers that eutrophication has had dramatic impacts on the coastal ecosystems, particularly at the Egyptian and Tunisian sites.

  7. Eutrophication patterns in an eastern Mediterranean coastal lagoon: Vassova, Delta Nestos, Macedonia, Greece

    Directory of Open Access Journals (Sweden)

    S. ORFANIDIS

    2005-12-01

    Full Text Available The results of an intensive monitoring study of main eutrophication parameters in relation to fish farming management, climate and hydrography in the Vassova coastal lagoon (Nestos Delta are presented. The overall aim is to produce basic knowledge in order to contribute to the management of eutrophication of coastal lagoons at local and national levels. Due to extensive spatiotemporal variability of the measured parameters correlation and regression polynomial analysis was used to identify patterns (p<0.05. Freshwater was the main source of nitrate and phosphate in the lagoon. This finding has justified the reduction of freshwater inflow in the past, which, however, has increased mean salinity to 30 PSU and reduced spatial salinity gradients. Maximum nitrate values in winter coincided with adverse climatic and hydrographic conditions (high precipitation, strong NE to E winds and low tide and fish farming management that hinder water circulation. Dissolved phosphorus variability indicated the combination of the external (freshwaters and internal (sediment P-sources. N/P water values indicated nitrogen being the most important nutrient for primary producers throughout the year, except in winter, when phosphorus was the most important nutrient. Practical measures for improving fish farming practices to decrease “eutrophication risk” during winter are suggested. Existing nutrient data from the Vassova and from other Greek lagoons in comparison were also presented and discussed.

  8. Nutrient dynamics in tropical rivers, lagoons, and coastal ecosystems of eastern Hainan Island, South China Sea

    Science.gov (United States)

    Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

    2014-01-01

    Nutrient dynamics based on field observations made along the eastern Hainan Island during the period 2006-2009 were investigated to understand nutrient biogeochemical processes, and to provide an overview of human perturbations of coastal ecosystems in this tropical region. The rivers showed seasonal variations in nutrient concentrations, with enrichment of dissolved inorganic nitrogen and dissolved silicate, and depletion of PO43-. High riverine concentrations of nitrate mainly originated from agricultural fertilizer inputs. The DIN : PO43- ratios ranged from 37 to 1063, suggesting preferential depletion of PO43- relative to nitrogen in rivers. Chemical weathering in the drainage area might explain the high levels of dissolved silicate. Aquaculture ponds contained high concentrations of NH4+ and dissolved organic nitrogen. The particulate phosphorus concentrations in the study area were lower than those reported for estuaries worldwide. The particulate silicate levels in rivers and lagoons were lower than the global average level. Nutrient biogeochemistry in coastal areas was affected by human activities (e.g., aquaculture, agriculture), and by natural phenomena including typhoons. The nutrient concentrations in coastal waters were low because of dispersion of land-derived nutrients in the sea. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes are magnified by estuarine processes (e.g., regeneration, desorption) in estuaries and Laoyehai Lagoon, but not in Xiaohai Lagoon. Riverine and groundwater inputs were the major sources of nutrients to Xiaohai and Laoyehai lagoons, respectively, and riverine inputs and aquaculture effluents were the major sources for the eastern coast of Hainan Island. Nutrient inputs to the coastal ecosystem increased with typhoon-induced runoff of rainwater, elucidating the important influence of typhoons on small tropical rivers.

  9. Environmental influences on fish assemblage distribution of an estuarine coastal lagoon, Ria de Aveiro (Portugal)

    OpenAIRE

    Pombo, L.; M. Elliott; Rebelo, J. E.

    2005-01-01

    Fish assemblage was examined for patterns in spatial and seasonal structure within an estuarine coastal lagoon, Ria de Aveiro. Two years of variation in abiotic conditions were recorded to identify factors responsible for maintaining the structure of fish assemblages. Nine sites were sampled monthly with a traditional “chincha” beach-seine net between November 1998 and October 2000. Fish abundance and biomass changed significantly between sites. Temperature was found to be the most important ...

  10. Seasonal and temporal dynamics of macrophytic assemblages and abiotic parameters of coastal lagoons in Western Greece (Mediterranean Sea)

    Science.gov (United States)

    Christia, Chrysoula; Papastergiadou, Eva

    2014-05-01

    Coastal lagoons are considered naturally stressed systems that experience frequent environmental disturbances and fluctuations and they are usually considered as physically controlled ecosystems. Coastal lagoons of Western Greece are representative of four different lagoon types covering a wide range of physiographical and hydrological characteristics. The seasonal differences in the physico-chemical parameters monitored from 2005 to 2007 were reduced in lagoon types (II and III) which characterized by better seawater communication when compared with the chocked lagoon types (Type I and IV). The latter types showed lower salinity values and high nutrient concentrations especially during the wet period. The macrophytic assemblages of coastal lagoons are typically dominated by few genera with great environmental plasticity and salinity competition, among other structuring abiotic variables. The implementation of DCA analysis revealed five distinct macrophytic assemblages in which dominant species were the angiosperms Zostera noltii, Ruppia cirrhosa, Cymodocea nodosa, Potamogeton pectinatus, the charophytes Lamprothamnium papulosum and Chara hispida f. corfuensis, as well as species preferring more marine conditions such as Acanthophora nayadiformis and Cystoseira barbata. The lagoon type IV differs from all other distinguished lagoon types due to the dominance of the species Potamogeton pectinatus and the charophyte Chara hispida f. corfuensis. Regarding the macrophytic assemblages and the univariate variables, important differences were recorded between lagoon types. Chocked lagoons showed low number of species and Shannon diversity index comparing with restricted lagoon types (Types II and III). The multiple linear regression analysis showed that transparency, pH, nitrates, alkalinity and Chl-a could affect the values of the above variables. A decline of angiosperms was referred on a worldwide scale and recorded also in coastal lagoons of Western Greece. A gradual

  11. Coastal lagoon sediments and benthic foraminifera as indicator for Holocene sea-level change: Samsø, southern Kattegat

    DEFF Research Database (Denmark)

    Sander, Lasse; Morigi, Caterina; Pejrup, Morten

    . Over time, an extensive beach ridge system formed, which eventually connected the islands, giving Samsø its characteristic shape. Ephemeral shallow-water lagoons evolved in topographic depressions along the shores of the island, most of which became inactive until today. A semi-enclosed coastal lagoon......-level and to investigate associated geomorphic responses in coastal lagoon and beach ridge systems. Vibracorings will be carried out in these sedimentary environments and will be supplemented with manual auger corings and ground penetrating radar (GPR) surveys to assess vertical variations in the deposited sediments....... The aim is to facilitate a three dimensional interpretation of processes, rates, and dynamics of coastal lagoons and associated systems. Recent foraminiferal assemblages will be employed to support facies description and interpretation of collected sediment cores. The use of benthic foraminifera...

  12. Hydrodynamics of a shallow coastal lagoon with submarine groundwater discharge: a numerical modeling exercise

    Science.gov (United States)

    Casares, R.; Marino-Tapia, I.

    2013-05-01

    Coastal lagoons are subjected to physical forces that make them vulnerable to climate change and human intervention. The karstic geology along the coastal zone of Yucatan Peninsula, Mexico, forces groundwater to discharge in the sea and coastal lagoons through underground conduits that can form small but numerous and scattered underwater springs. These freshwater inputs, along with other physical forces like ocean tides and meteorological events, can have a significant effect on the circulation and residence times in coastal lagoons. Climate change consequences such as sea level rise and changing rain patterns, as well as the increasing human impact, can cause or aggravate certain environmental effects. Since coastal lagoons provide important environmental services there is a need to understand and have predictive capability to simulate the transport processes and the forces acting on them. The present study was carried out in the coastal lagoon of Celestun, located at NW Yucatan Peninsula, a region of karstic geology. The aim of this research is to understand the barotropic hydrodynamic functioning of this shallow system, taking into account the oceanographical, meteorological and hydrological forcing. Emphasis is made on the residence times in different parts of the lagoon, and the effects of freshwater inputs. For the detailed understanding of the processes the hydrodynamic numerical model DELFT3D was implemented. The model was validated with data gathered on the field during two intensive oceanographic campaigns, which included installation of CTDs and acoustic current meters at strategic sites distributed in the system, and detailed bathymetric measurements using an echosounder coupled with a differential GPS on board of a motorboat. In order to improve model performance a sensitivity analysis to the main variables involved in the model was carried out, among them: the size of the grid cells, grid depth, time step, friction coefficients, boundary conditions

  13. Factors involved in spatiotemporal dynamics of submerged macrophytes in a Portuguese coastal lagoon under Mediterranean climate

    Science.gov (United States)

    Antunes, Cristina; Correia, Otília; Marques da Silva, Jorge; Cruces, Anabela; Freitas, Maria da Conceição; Branquinho, Cristina

    2012-09-01

    Submerged macrophytes are key in coastal ecosystems, with important structural and functional roles. Thus, the characterization of the submerged aquatic vegetation dynamics is of prime importance for assessing the ecological status of coastal ecosystems. The main aim of this study was to assess the spatial and temporal dynamics of submerged macrophytes biomass in a temporarily open coastal lagoon in Melides, Portugal, and to evaluate the physiological performance of the dominant macrophyte in the system. This lagoon is subject to several disturbances such as the dramatic changes in water physicochemical parameters over time, since temporarily opens to the sea occur renewing the lagoon water content. Moreover it is under a Mediterranean climate with the inherently high temporal variability of precipitation and high temperatures during the summer. Our study shows that the submerged macrophyte community was dominated initially by Ruppia cirrhosa and then replaced by Potamogeton pectinatus, which showed a marked temporal and spatial pattern with extremely high values of biomass in August and in the inner part of the lagoon. The spatial and temporal biomass patterns in submerged macrophytes were mainly related with water level, salinity, pH and transparency. The physiological performance of R. cirrhosa was lower when there was greater biomass accumulation and in extremely shallow waters, whereas physiological vigor seemed to be greater at moderate temperatures and in areas with higher salinity and dissolved oxygen. The data from this study can be used to predict submerged biomass macrophyte responses to extreme water quality changes and to feed a decision support system for the best period to promote the seasonal artificial breaching of the sandy barrier.

  14. Tidal hydrodynamics in a two-inlet coastal lagoon in the Gulf of California

    Science.gov (United States)

    Serrano, David; Ramírez-Félix, Evlin; Valle-Levinson, Arnoldo

    2013-07-01

    The aim of this study is to understand the effects of friction and advection in the hydrodynamics of a two-inlet coastal lagoon, Santa María La Reforma, in Northwest Mexico. A vertically integrated numerical model is used to describe sea level variations and tidal currents, and to study the dynamics inside the system. Observed sea level and current measurements were used to calibrate the model. Results show a ˜90 min phase lag of the tidal signal in the center of the system with respect to both inlets. Tidal currents greater than 1.0 m s-1 were recorded and modeled at both inlets. The sea level in the lagoon shows one-quarter of period of M2 out of phase (˜3 h) with respect to the velocity. Bottom friction generated the greatest M4 harmonic and largest tidal asymmetries at the narrowest section of the lagoon, ˜35 km away from the inlets. The tidal momentum balance along the main axis of the lagoon was dominated by pressure gradient and friction, describing a quasi-standing tidal wave in currents and in amplitude. This behavior resulted from waves traveling in opposite directions from the two tidal inlets, causing constructive interference in elevation but destructive interference inflow.

  15. Effect of mangrove forest structures on wave attenuation in coastal Vietnam

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    Tran Quang Bao

    2011-09-01

    Full Text Available This paper analyses wave attenuation in coastal mangrove forests in Vietnam. Data from 32 mangrove plots of six species located in 2 coastal regions are used for this study. In each plot, mangrove forest structures and wave height at different cross-shore distances are measured. Wave height closely relates to cross-shore distances. 92 exponential regression equations are highly significant with R2 > 0.95 and P val. < 0.001. Wave height reduction depends on initial wave height, cross-shore distances, and mangrove forest structures. This relationship is used to define minimum mangrove band width for coastal protection from waves in Vietnam.

  16. Coastal lagoons and beach ridges as complementary sedimentary archives for the reconstruction of Holocene relative sea-level changes

    DEFF Research Database (Denmark)

    Sander, Lasse; Hede, Mikkel Ulfeldt; Fruergaard, Mikkel

    2016-01-01

    Coastal lagoons and beach ridges are genetically independent, though non-continuous, sedimentary archives. We here combine the results from two recently published studies in order to produce an 8000-year-long record of Holocene relative sea-level changes on the island of Samsø, southern Kattegat......, Denmark. The reconstruction of the initial mid-Holocene sea-level rise is based on the sedimentary infill from topography-confined coastal lagoons (Sander et al., Boreas, 2015b). Sea-level index points over the mid- to late Holocene period of sea-level stability and fall are retrieved from the internal...... proximate occurrence of coastal lagoons and beach ridges allows us to produce seamless time series of relative sea-level changes from field sites in SW Scandinavia and in similar coastal environments....

  17. Will nutrient and light limitation prevent eutrophication in an anthropogenically-impacted coastal lagoon?

    Science.gov (United States)

    Domingues, Rita B.; Guerra, Cátia C.; Barbosa, Ana B.; Galvão, Helena M.

    2017-06-01

    The Ria Formosa coastal lagoon (southern Portugal) is a highly productive and valuable temperate ecosystem, subjected to strong anthropogenic impacts and highly vulnerable to climate change. The main goal of this work is to understand ecosystem susceptibility to eutrophication, by evaluating the isolated and combined effects of nutrient (N, P and Si) and light enrichments on phytoplankton growth and community composition during autumn, winter and spring. Microcosms of natural phytoplankton collected in the lagoon were subjected to different nutrient and light treatments and incubated in situ for 48 h. Nutrient consumption, and phytoplankton growth and community structure were evaluated using spectrophotometric methods, and inverted and epifluorescence microscopy. Diatoms were the only group potentially limited by nitrogen, and only during spring. Increased nutrient consumptions were observed for all nutrient additions in all seasons, not associated with phytoplankton growth, suggesting that luxury consumption was used to build up intracellular nutrient pools. Responses to light enrichment were inconsistent among phytoplankton groups, probably due to a high taxonomic seasonal variability. Positive responses to light enrichment were mostly observed during winter. Negative synergistic interactions between nutrients and light were also observed. We conclude that eutrophication is currently not a problem in the Ria Formosa coastal lagoon, but future nutrient enrichments may lead to accelerated growth of specific functional groups and species, if light is not limiting.

  18. Feeding ecology of juvenile marine fish in a shallow coastal lagoon of southeastern Mexico

    Directory of Open Access Journals (Sweden)

    Daniel Arceo-Carranza

    2015-09-01

    Full Text Available Many species of marine fish use coastal lagoons during early stages of their life cycles due to the protection provided by their turbid waters and complex structure of the environment, such as mangroves and mudflats, and the availability of food derived from the high productivity of these sites. In this study, we analyzed the diet of six species of juvenile marine fishes that use a karstic lagoon system in the northwest portion of the Yucatan Peninsula, Mexico. Through stomach contents analysis we determined the trophic differences among Caranx latus, Oligoplites saurus, Trachinotus falcatus, Synodus foetens, Lutjanus griseus, and Strongylura notata. C. latus, O. saurus, S. foetens, and S. notate, which are ichthyophagous species (>80% by number. L. griseus feeds mainly on crustaceans (>55% and fish (35%, while T. falcatus feeds on mollusks (>50% bivalves, >35% gastropods. The analysis of similarities (ANOSIM showed differences in the diet of all species. Cluster analysis, based on the Bray-Curtis similarity matrix revealed three groups; one characterized by the ichthyophagous guild (S. notata, S. foetens, C. latus, and O. saurus, other group formed by the crustacean consumers (L. griseus, and the third, composed by the mollusk feeder (T. falcatus. Species of the ichthyophagous guild showed overlap in their diets, which under conditions of low prey abundance may trigger competition, hence affecting juvenile stages of these marine species that use coastal lagoons to feed and grow.

  19. Assessment of ecological quality of coastal lagoons with a combination of phytobenthic and water quality indices.

    Science.gov (United States)

    Christia, Chrysoula; Giordani, Gianmarco; Papastergiadou, Eva

    2014-09-15

    Coastal lagoons are ecotones between continents and the sea. Coastal lagoons of Western Greece, subjected to different human pressures, were classified into four different types based on their hydromorphological characteristics and monitored over a three year period for their biotic and abiotic features. Six ecological indices based on water quality parameters (TSI-Chl-a, TSI-TP, TRIX), benthic macrophytes (E-MaQI, EEI-c) and an integrated index TWQI, were applied to assess the ecological status of studied lagoons under real conditions. The trophic status ranged from oligotrophic to hypertrophic according to the index applied. The ecological quality of transitional water ecosystems can be better assessed by using indices based on benthic macrophytes as changes in abundance and diversity of sensitive and tolerant species are the first evidence of incoming eutrophication. The multi-parametric index TWQI can be considered appropriate for the ecological assessment of these ecosystems due to its robustness and the simple application procedure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Evaluating the human impact on groundwater quality discharging into a coastal reef lagoon

    Science.gov (United States)

    Rebolledo-Vieyra, M.; Hernandez-Terrones, L.; Soto, M.; Lecossec, A.; Monroy-Rios, E.

    2008-12-01

    The Eastern coast of the Yucatan Peninsula has the fastest growth rate in Mexico and groundwater is the only source of drinking water in the region. The consequences of the lack of proper infrastructure to collect and treat wastewater and the impact of human activities on the quality of groundwater are addressed. The groundwater in the coastal aquifer of Quintana Roo (SE Mexico) discharges directly into the ocean. In addition, the coral reef of the Eastern Yucatan Peninsula is part of the Mesoamerican Coral Reef System, one of the largest in the world. The interaction of the reef-lagoon hydraulics with the coastal aquifer of Puerto Morelos (NE Yucatan Peninsula), and a major input of NH4, SO4, SiO2, as a consequence of the use of septic tanks and the lack of modern wastewater treatment plants are presented. No seasonal parameters differences were observed, suggesting that groundwater composition reaching the reef lagoon is not changing seasonally. A conceptual model of the coastal aquifer was developed, in order to explain how the human activities are impacting directly on the groundwater quality that, potentially, will have a direct impact on the coral reef. The protection and conservation of coral reefs must be directly related with a policy of sound management of coastal aquifers and wastewater treatment.

  1. Impacts of maintenance channel dredging in a northern Adriatic coastal lagoon. I: Effects on sediment properties, contamination and toxicity

    Science.gov (United States)

    Guerra, Roberta; Pasteris, Andrea; Ponti, Massimo

    2009-10-01

    Conservation and management of coastal lagoons envisage direct human intervention. To prevent siltation and to preserve the hydrodynamics features of the lagoon system, the inner channels undergo regular maintenance dredging. Sediment properties (RDP, organic matter, grain size), trace metals (Cd, Cu, Cr, Hg, Ni, and Pb), and toxicity vs. the amphipod Corophium insidiosum and the luminescent bacterium Vibrio fischeri, were analysed before and after dredging operations in a coastal lagoon (Pialassa Baiona, Italy). To detect the actual impacts, disturbed sites were contrasted with multiple controls in two distinct times, i.e. before and after disturbance, according to a sampling design based on Beyond BACI principles. The integrated methodology here adopted suggests that dredging operations carried out are not likely to pose dramatic effects on environmental quality of the lagoon.

  2. An object-based image analysis approach for aquaculture ponds precise mapping and monitoring: a case study of Tam Giang-Cau Hai Lagoon, Vietnam.

    Science.gov (United States)

    Virdis, Salvatore Gonario Pasquale

    2014-01-01

    Monitoring and mapping shrimp farms, including their impact on land cover and land use, is critical to the sustainable management and planning of coastal zones. In this work, a methodology was proposed to set up a cost-effective and reproducible procedure that made use of satellite remote sensing, object-based classification approach, and open-source software for mapping aquaculture areas with high planimetric and thematic accuracy between 2005 and 2008. The analysis focused on two characteristic areas of interest of the Tam Giang-Cau Hai Lagoon (in central Vietnam), which have similar farming systems to other coastal aquaculture worldwide: the first was primarily characterised by locally referred "low tide" shrimp ponds, which are partially submerged areas; the second by earthed shrimp ponds, locally referred to as "high tide" ponds, which are non-submerged areas on the lagoon coast. The approach was based on the region-growing segmentation of high- and very high-resolution panchromatic images, SPOT5 and Worldview-1, and the unsupervised clustering classifier ISOSEG embedded on SPRING non-commercial software. The results, the accuracy of which was tested with a field-based aquaculture inventory, showed that in favourable situations (high tide shrimp ponds), the classification results provided high rates of accuracy (>95 %) through a fully automatic object-based classification. In unfavourable situations (low tide shrimp ponds), the performance degraded due to the low contrast between the water and the pond embankments. In these situations, the automatic results were improved by manual delineation of the embankments. Worldview-1 necessarily showed better thematic accuracy, and precise maps have been realised at a scale of up to 1:2,000. However, SPOT5 provided comparable results in terms of number of correctly classified ponds, but less accurate results in terms of the precision of mapped features. The procedure also demonstrated high degrees of reproducibility

  3. Organic matter composition in the sediment of three Brazilian coastal lagoons: district of Macaé, Rio de Janeiro (Brazil

    Directory of Open Access Journals (Sweden)

    Zink Klaus-Gerhard

    2004-01-01

    Full Text Available Freshwater lagoons comprise important coastal ecosystems and natural buffers between urbanized land areas and open ocean in the Rio de Janeiro State, Brazil. Studies of sediment and water chemistry, zooplankton and bacterial communities to assess the extent of anthropogenic disturbance are available. Here we contribute with an organic-geochemical approach supplemented by some microbiological aspects to complete the characterization of these lagoonal ecosystems. Bulk organic matter and extractable lipids (aliphatic hydrocarbons, alcohols and fatty acids, sterols were investigated from two locations per lagoon: at the seaward site and landward ends - and at two depth intervals (0-3 and 3-6 cm per site. Urbanized Imboacica Lagoon received increased anthropogenic input over the most recent years represented by the topmost 3 cm of sediment, whereas deeper sediment layers are less affected by human influence. Eutrophication or nutrient availability favored enhanced algal/cyanobacterial growth. In remote Cabiúnas and Comprida Lagoons pristine conditions are preserved. Organic matter from vascular plants dominates (chain length of free lipids up to C36, which is exceptionally well preserved by acidic lagoonal waters. Differentiation between landward and seaward sites in these two lagoons is less well established due to much smaller surface/volume to catchment ratios. No anthropogenic influences are yet detectable in sediments of Cabiúnas and Comprida Lagoons.

  4. Neotropical coastal lagoons: an appraisal of their biodiversity, functioning, threats and conservation management

    Directory of Open Access Journals (Sweden)

    FA. Esteves

    Full Text Available Neotropical coastal lagoons (NCL are human-dominated ecosystems. Their distribution along densely populated coastal areas of developing countries makes these systems among the most threatened in the world. Here, we summarize some aspects of the causes and consequences of NCL biodiversity, their functioning, their importance to the surrounding populations, their fragility, and their responses to local and global anthropogenic impacts and the challenges that Neotropical countries face in conserving these systems. Although still scarce and geographically concentrated, a growing body of studies has shown that NCLs are physiographically diversified systems, which harbor a considerable and particular proportion of the Neotropical inland aquatic biodiversity. Despite the fact that coastal lagoons are ecotones that are intricately connected to surrounding environments, they develop mechanisms for structural and functional regulation, which confer to these systems higher productivity and carrying capacities than surrounding ecosystems. Such traits attract residential developments and subsidize local traditional populations with important economic and aesthetic ecosystem revenues such as fisheries and scenic beauty. However, the disorganized human occupation around NCLs are causing profound impacts such as eutrophication, salinization, exotic species introduction, as well as other effects, which are ultimately imposing major habitat degradations and biodiversity extirpations in NCLs. We argue that interdisciplinary conservation strategies, which integrate scientific expertise, government officials, private companies and the general public, are the most likely to overcome the geographic and economic obstacles to NCL conservation.

  5. Mediterranean coastal lagoons in an ecosystem and aquatic resources management context

    Science.gov (United States)

    Pérez-Ruzafa, A.; Marcos, C.; Pérez-Ruzafa, I. M.

    Aquatic ecosystems, water resources and their management are some of the main problems facing humanity. These problems vary from water scarcity and deteriorating quality for human consumption and use, to floods in areas with torrential rainfall, rising sea levels in coastal zones, the overexploitation of living resources and the loss of ecological quality and biodiversity. Proper water management needs to follow a hierarchical perspective, ranging from the whole planet to individual water bodies. Spatio-temporal scales change at each level, as do driving forces, impacts, and the processes and responses involved. Recently, the European Union adopted the Water Framework Directive (WFD) to establish the basic principles of sustainable water policy in member states, one of the main concerns being the need to consider the vulnerability of coastal aquatic ecosystems and to establish their ecological status. However, from a Mediterranean point of view, the actions of European countries (under the WFD regulations) and non-EU countries need to be coordinated. There are more than 100 coastal lagoons in the Mediterranean. They are habitats with an important ecological role, but also provide essentials goods and services for humans. In the present work, we look at the problems involved in understanding their definition and management. At water body management level, we emphasise that scientific cooperation is necessary to deal with the conceptual and ecological difficulties derived from inter and intra-lagoon variability in hydrology and biological assemblages, inherent factors in the functioning of these complex ecosystems.

  6. Estimating Coastal Lagoon Tidal Flooding and Repletion with Multidate ASTER Thermal Imagery

    Directory of Open Access Journals (Sweden)

    Thomas R. Allen

    2012-10-01

    Full Text Available Coastal lagoons mix inflowing freshwater and tidal marine waters in complex spatial patterns. This project sought to detect and measure temperature and spatial variability of flood tides for a constricted coastal lagoon using multitemporal remote sensing. Advanced Spaceborne Thermal Emission Radiometer (ASTER thermal infrared data provided estimates of surface temperature for delineation of repletion zones in portions of Chincoteague Bay, Virginia. ASTER high spatial resolution sea-surface temperature imagery in conjunction with in situ observations and tidal predictions helped determine the optimal seasonal data for analyses. The selected time series ASTER satellite data sets were analyzed at different tidal phases and seasons in 2004–2006. Skin surface temperatures of ocean and estuarine waters were differentiated by flood tidal penetration and ebb flows. Spatially variable tidal flood penetration was evaluated using discrete seed-pixel area analysis and time series Principal Components Analysis. Results from these techniques provide spatial extent and variability dynamics of tidal repletion, flushing, and mixing, important factors in eutrophication assessment, water quality and resource monitoring, and application of hydrodynamic modeling for coastal estuary science and management.

  7. Implementation challenges of climate change adaptation initiatives in coastal lagoon communities in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Luz María Vázquez

    2017-10-01

    Full Text Available Abstract This paper explores some key challenges the Mexican government may face when implementing climate change adaptation initiatives in coastal lagoon communities in the Mexican state of Tabasco, in the Gulf of Mexico. I discuss some challenges state initiatives of this type may encounter considering the existence of local contentious political issues among various actors – fishers and the state-owned oil industry – that are at the core of the emergence of coastal environmental changes in the study site. A close analysis of local political, economic and environmental processes in coastal lagoon communities illustrates the existence of contentious issues among powerful actors over territory and its resources. It is in the context of these local, on the ground, issues that I argue that climate change adaptation interventions become highly political. I also argue that climate change policy analysis must be done in light of past and failed state interventions in Tabasco that have had a negative impact on ecosystems and fishers’ livelihoods. My analysis of climate change adaptation initiatives and fishers’ views on their local environmental problems is based on political ecology approaches to environmental narratives and critical literature on climate change.

  8. Alien species of fish parasites in the coastal lakes and lagoons of the southern Baltic

    Directory of Open Access Journals (Sweden)

    Jolanta Morozińska-Gogol

    2009-03-01

    Full Text Available Alien species are now found all over the world. New fish parasites have been unintentionally introduced with infected alien fish imported for aquaculture or have sometimes spread with their intermediate invertebrate hosts transported in the ballast waters of ships. Four alien fish parasites have been recorded in Polish coastal lakes and lagoons, all parasitising eels. Three were introduced with the final host - the Japanese eel - introduced for aquaculture (Anguillicola crassus, Pseudodactylogyrus anguillae and Pseudodactylogyrus bini and one (Paratenuisentis ambiguus with its sole intermediate host (Gammarus tigrinus.

  9. Temporal and spatial fluctuations of phytoplankton in a tropical coastal lagoon, southeast Brazil

    Directory of Open Access Journals (Sweden)

    S. Melo

    Full Text Available Spatial and temporal variability of the phytoplankton community in the tropical coastal Imboassica lagoon, an environment naturally isolated from the ocean by a narrow sandbar, was analysed every two weeks for 19 months by sampling three sites. During this study, the lagoon received direct input of marine water three times, resulting in remarkable salinity, nutrient concentrations and phytoplankton biomass variations in both temporal and spatial aspects. The phytoplankton biomass presented relatively low values ranging, on average, from 0.54 mg.L-1 in the station closest to the sea (station 1 to 1.34 mg.L-1 in the station close to a macrophyte bank (station 3. Diatoms and cryptomonads dominated in stations 1 and 2 (located relatively close to station 1, yet receiving the runoff of domestic sewage, and euglenoids, cryptomonads and dinoflagellates at station 3. Stations 1 and 2 usually presented the same dominant species but station 2 presented a higher phytoplankton biomass. On the other hand, station 3 showed more similar results concerning phytoplankton biomass with station 2, however the dominant species were usually different. The high fluctuations of salinity and the reduced nutrient availability are pointed out as the main factors structuring the dynamics of the phytoplankton community at the Imboassica lagoon.

  10. The Influence of Wind and Tide on the Hydrodynamics of a Highly Frictional Coastal Lagoon System

    Science.gov (United States)

    Polanco-Arias, C.; Marino-Tapia, I.; Enriquez, C.

    2016-02-01

    This study is focused on the influence of wind and tide on the hydrodynamics of a tropical coastal lagoon in Telchac, Yucatan, Mexico. The system is very shallow (z boats. Water level and velocity data gathered during one month in the summer of 2009, shows the expected attenuation of the tidal signal in the head of the system, but during the final ten days of the campaign there is an unusual behavior where the water level in the lagoon head was between 16% and 33% bigger than in the lagoon mouth. Analysis of the data shows a high coherence between the sea level and the wind velocity, primarily at diurnal frequencies. This reinforces the hypothesis of a synchronization between strong sea breezes and the predominant diurnal tide in such a way that amplification of the diurnal signal can occur at the head. Numerical simulations using the Delft3D model are performed to confirm this hypothesis and to better understand the conditions under which such phenomenon can occur. The effects of basin orientation, shape and depth are investigated with the numerical model.

  11. Environmental dynamics as a structuring factor for microbial carbon utilization in a subtropical coastal lagoon

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    Cecilia eAlonso

    2013-02-01

    Full Text Available Laguna de Rocha belongs to a series of shallow coastal lagoons located along South America. It is periodically connected to the sea through a sand bar, exhibiting a hydrological cycle where physicochemical and biological gradients are rapidly established and destroyed. Its most frequent state is the separation of a Northern zone with low salinity, high turbidity and nutrient load, and extensive macrophyte growth, and a Southern zone with higher salinity and light penetration, and low nutrient content and macrophyte biomass. This zonation is reflected in microbial assemblages with contrasting abundance, activity and community composition. The physicochemical conditions exerted a strong influence on community composition, and transplanted assemblages rapidly transformed to resembling the community of the recipient environment. Moreover, the major bacterial groups responded differently to their passage between the zones, being either stimulated or inhibited by the environmental changes, and exhibiting contrasting sensitivities to gradients. Addition of allochthonous carbon sources induced pronounced shifts in the bacterial communities, which in turn affected the microbial trophic web by stimulating heterotrophic flagellates and virus production. By contrast, addition of organic and inorganic nutrient sources (P or N did not have significant effects. Altogether, our results suggest that i the planktonic microbial assemblage of this lagoon is predominantly carbon limited, ii different bacterial groups cope differently with this constraint, and iii the hydrological cycle of the lagoon plays a key role for the alleviation or aggravation of bacterial carbon limitation. Based on these findings we propose a model of how hydrology affects the composition of bacterioplankton and of carbon processing in Laguna de Rocha. This might serve as a starting hypothesis for further studies about the microbial ecology of this lagoon, and of comparable transitional

  12. Simulated terrestrial runoff triggered a phytoplankton succession and changed seston stoichiometry in coastal lagoon mesocosms.

    Science.gov (United States)

    Deininger, A; Faithfull, C L; Lange, K; Bayer, T; Vidussi, F; Liess, A

    2016-08-01

    Climate change scenarios predict intensified terrestrial storm runoff, providing coastal ecosystems with large nutrient pulses and increased turbidity, with unknown consequences for the phytoplankton community. We conducted a 12-day mesocosm experiment in the Mediterranean Thau Lagoon (France), adding soil (simulated runoff) and fish (different food webs) in a 2 × 2 full factorial design and monitored phytoplankton composition, shade adaptation and stoichiometry. Diatoms (Chaetoceros) increased four-fold immediately after soil addition, prymnesiophytes and dinoflagellates peaked after six- and 12 days, respectively. Soil induced no phytoplankton shade adaptation. Fish reduced the positive soil effect on dinoflagellates (Scripsiella, Glenodinium), and diatom abundance in general. Phytoplankton community composition drove seston stoichiometry. In conclusion, pulsed terrestrial runoff can cause rapid, low quality (high carbon: nutrient) diatom blooms. However, bloom duration may be short and reduced in magnitude by fish. Thus, climate change may shift shallow coastal ecosystems towards famine or feast dynamics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. How climate change threats water resource: the case of the Thau coastal lagoon (Mediterranean Sea, France)

    Science.gov (United States)

    La Jeunesse, Isabelle; Sellami, Haykel; Cirelli, Claudia

    2014-05-01

    The latest reports of the intergovernmental panel on climate change explained that the Mediterranean regions are especially vulnerable to the impacts of climate change. These latest are expected to have strong impacts on the management of water resources and on regional economies. The aim of this paper is to discuss impacts of climate changes on the Thau case study in relation to the evolution of water balance, water uses and adaptation to climate change. The Thau coastal lagoon is located in the Mediterranean coast in south of France in the Languedoc-Roussillon Region. Economic activities are diverse from shellfish farming, fertilizers industries to agriculture and tourism. However, tourism and shellfish farming are of major importance for local economy. If tourism is mainly turned to the Sea coast, shellfishes grow within the lagoon and rely on water quality. Previous studies have demonstrated the link between the coastal lagoon water quality and inputs of freshwater from the catchment. Thus, changes in rainfalls, runoff and water balance would not only affect water uses but also water quality. Climate changes projections are presented following the implementation of 4 downscaled climatic models. Impacts on water balance are modelled with SWAT (Soil Water Assessment Tool) for 2041-2070 compared to the 1971-2000 reference period. The decrease of precipitations and water balance will impact discharges and thus decrease the freshwater inputs to the coastal lagoon. A study of water uses conducted in interactions with stakeholders within the Thau area has permitted to assess both current and evolution of water uses. It has revealed local water resources are depleting while water demand is increasing and is planned to continue to increase in the really near future. To prevent water scarcity events, mainly due to the climate change context, the Regional authorities have connected the catchment to the Rhône river to import water. The conclusion of this study is while

  14. Does coastal lagoon habitat quality affect fish growth rate and their recruitment? Insights from fishing and acoustic surveys

    Science.gov (United States)

    Brehmer, P.; Laugier, T.; Kantoussan, J.; Galgani, F.; Mouillot, D.

    2013-07-01

    Ensuring the sustainability of fish resources necessitates understanding their interaction with coastal habitats, which is becoming ever more challenging in the context of ever increasing anthropogenic pressures. The ability of coastal lagoons, exposed to major sources of disturbance, to provide resources and suitable habitats for growth and survival of juvenile fish is especially important. We analysed three lagoons with different ecological statuses and habitat quality on the basis of their eutrophication and ecotoxicity (Trix test) levels. Fish abundances were sampled using fishing and horizontal beaming acoustic surveys with the same protocols in the same year. The relative abundance of Anguilla anguilla, Dicentrarchus labrax or the Mugilidae group was not an indicator of habitat quality, whereas Atherina boyeri and Sparus aurata appeared to be more sensitive to habitat quality. Fish abundance was higher in the two lagoons with high eutrophication and ecotoxicity levels than in the less impacted lagoon, while fish sizes were significantly higher in the two most severely impacted lagoons. This leads us to suggest low habitat quality may increase fish growth rate (by the mean of a cascading effect), but may reduce lagoon juvenile abundance by increasing larval mortality. Such a hypothesis needs to be further validated using greater investigations which take into account more influences on fish growth and recruitment in such variable environments under complex multi-stressor conditions.

  15. Fishes as indicators of untreated sewage contamination in a Mexican coastal lagoon.

    Science.gov (United States)

    Aguilar-Betancourt, Consuelo M; González-Sansón, Gaspar; Kidd, Karen A; Munkittrick, Kelly R; Curry, R Allen; Kosonoy-Aceves, Daniel; Lucano-Ramírez, Gabriela; Ruiz-Ramírez, Salvador; Flores-Ortega, Juan R

    2016-12-15

    Lagoons are important nursery habitats for fishes but are often sites of intense human activity including wastewater discharges. The goal of this research was to compare stable nitrogen (δ(15)N) and carbon (δ(13)C) isotopes, total mercury (THg) and other metal levels in four selected fish species among sites with different levels of untreated sewage discharge inside Barra de Navidad coastal lagoon in the Mexican Pacific. Three species from sites heavily impacted by sewage showed higher δ(15)N and δ(13)C compared to those from non-impacted sites. In addition, the highest concentrations of THg were present in fish of two species (Sciades guatemalensis and Diapterus brevirostris) collected at the two most impacted sites, and exceeded the 0.2μg/g ww threshold believed to be protective of adult and juvenile fish. No individuals of Achirus mazatlanus and Mugil curema exceeded this threshold, and liver somatic index and condition did not distinguish high from low impacted sites for all species. In general, the metal levels differed among species but not sites, and were lower than what has been measured in fishes elsewhere. The study also provides the first information on several fish species for coastal areas of Mexico, suggests that THg and isotopes can distinguish sewage-impacted sites, and can serve as a baseline for future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Macrofaunal patterns and animal-sediment relationships in Uruguayan estuaries and coastal lagoons (Atlantic coast of South America)

    Science.gov (United States)

    Giménez, L.; Venturini, N.; Kandratavicius, N.; Hutton, M.; Lanfranconi, A.; Rodríguez, M.; Brugnoli, E.; Muniz, P.

    2014-03-01

    Estuaries vary considerably in geomorphology, hydrology and in the properties of sediments. Structure of benthic communities may respond to the interaction of these estuarine characteristics, resulting in between site differences. This work evaluated several hypothetical scenarios to explain variation in macrofaunal communities in permanently open estuaries and open/closed coastal lagoons of the coast of Uruguay, South America. Of particular relevance were three hypothetical scenarios: (1) that sediment characteristics, temperature or conductivity may explain variation in fauna between estuarine habitat types (estuaries vs. lagoons), (2) that fauna may not vary between habitat types, but may vary among sites in response to environmental variables and (3) that fauna differed between habitat types but patterns were not clearly being mediated by the measured environmental variables. Scenario 1 was discarded because none of the observed environmental variables showed a significant habitat effect. Patterns of species richness differed between lagoons and estuaries in accordance with scenario 3; richness was higher in open/closed lagoons than in estuaries. The abundance of three important infaunal species supported scenario 2: these species varied considerably among sites in response to the proportion of different sand fractions. Fine sands, common in all estuaries and in a lagoon, were characterised by polychaetes (Laeonereis acuta and Alitta succinea) whereas coarse sands, found in two lagoons were characterised by a bivalve, Erodona mactroides. Another three species responded to sediment but did not show clear site to site variation in abundance. Lagoons differ from estuaries in their higher site to site variation in sediment composition and in the diversity of community variants: lagoons may therefore increase regional diversity as compared to estuaries. We conclude that sediment type played a strong role in explaining variations in macrofaunal abundance among

  17. Long-term and high resolution measurements of bed level changes in a temperate, microtidal coastal lagoon

    DEFF Research Database (Denmark)

    Andersen, Thorbjørn J.; Pejrup, Morten; Nielsen, Allan Aasbjerg

    2006-01-01

    This study presents the results of a long-term monitoring program of bed level changes measured during 8 yr at an intertidal mudflat in a microtidal, temperate coastal lagoon. Additionally, bed level measurements obtained at a 10-min temporal resolution at the same tidal flat and at the bed of a ...

  18. Experimental evidence of nitrogen control on pCO2 in phosphorus-enriched humic and clear coastal lagoon waters

    Directory of Open Access Journals (Sweden)

    Roberta Bittencourt Peixoto

    2013-02-01

    Full Text Available Natural and human-induced controls on carbon dioxide (CO2 in tropical waters may be very dynamic (over time and among or within ecosystems considering the potential role of warmer temperatures intensifying metabolic responses and playing a direct role on the balance between photosynthesis and respiration. The high magnitude of biological processes at low latitudes following eutrophication by nitrogen (N and phosphorus (P inputs into inland waters may be a relevant component of the C cycle, showing controls on partial pressure of CO2 (pCO2 that are still poorly understood. Here we assessed the strength of N control on pCO2 in P-enriched humic and clear coastal lagoons waters, using four experimental treatments in microcosms: control (no additional nutrients and three levels of N additions coupled to P enrichments. In humic coastal lagoon waters, a persistent CO2 supersaturation was reported in controls and all nutrient-enriched treatments, ranging from 24-fold to fourfold the atmospheric equilibrium value. However, both humic and clear coastal lagoon waters only showed significant decreases in pCO2 in relation to the controlled microcosms in the two treatments with higher N addition levels. Additionally, clear coastal lagoon water microcosms showed a shift from CO2 sources to CO2 sinks, in relation to the atmosphere. Only in the two more N-enriched treatments did pCO2 substantially decrease, from 650 µatm in controls and less N-enriched treatments to 10 µatm in more N-enriched microcosms. Humic substrates and N inputs can modulate pCO2 even in P-enriched coastal lagoon waters, thereby being important drivers on CO2 outgassing from inland waters.

  19. Phytoplankton relationship with bacterioplankton, dissolved carbohydrates and water characteristics in a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Pablo S. Guimarães

    2013-10-01

    Full Text Available Release of carbohydrates by phytoplankton enhances microbial diversity, promoting associations between algae and heterotrophic organisms. Thus, this work aimed to characterise the dissolved carbohydrates at a Brazilian subtropical coastal lagoon (Merin lagoon, in addition to determining their relationships with environmental parameters and phyto/bacterioplankton communities over one year. We analysed the relationships among physical, chemical and biological parameters by a principal component analysis (PCA after normalisation of data as z scores. Chlorophyceae showed the highest richness, although Bacillariophyceae and Cyanophyceae showed the highest densities. These classes are essentially represented by centric diatoms (Aulacoseira cf. muzzanensis and filamentous cyanobacteria (Planktolyngbya limnetica and Planktolyngbya cf. contorta. Merin lagoon showed a strong seasonal behaviour for most of parameters and phytoplanktonic density was mainly correlated with temperature, specific conductance, phosphate and total bright sunshine duration. Only combined dissolved carbohydrates (CDCHOs were found and their main components were glucose (31.6%, mannose/xylose (20.6%, ribose (13.9%, arabinose (8.9% and galacturonic acid (8.1%. The CDCHO amounts were higher in November, March-April and September and the December/January and July/August periods showed lower ones. Ribose was first detected only in the warm months and it gradually decreased with bacterial density. The carbohydrate concentration was coupled to phytoplanktonic density, except in December and January, when the bacterial density was increased. These results supported the significance of dissolved carbohydrates in associations with algae and bacteria in the freshwater planktonic environment. Our data reinforced the influence of phytoplankton community on the natural dissolved carbohydrate pool, besides the significance of such carbon source on the bacterial community dynamic.

  20. The potential of tidal barrages and lagoons to manage future coastal flood risk

    Science.gov (United States)

    Prime, Thomas; Wolf, Judith; Lyddon, Charlotte; Plater, Andrew; Brown, Jennifer

    2017-04-01

    In the face of a changing climate, adaptation and mitigation measures are important for coastal communities that seek to maintain their resilience to extreme events. Measures that can be classed as being both adaptation and mitigation can doubly contribute to this. Tide barrages and lagoons have the capacity to generate electricity from the rise and fall of the tide, which over the assets lifetime would contribute significantly towards emission reduction targets and towards a low carbon economy. In addition to electricity generation, the barrage or lagoon can also act as a flood defence during extreme events. This means that coastal communities protected by the barrage will have adaptation benefits to the increasing frequency of storm surges that are a result of sea-level rise. Finally, the barrage also has the potential to act as a transport link with vehicles able to cross, reducing travel times and emissions. The research project RISES-AM focuses on the implications of the higher end climate scenarios, particularly those with a global average warming that is greater than 2 ⁰C with respect to pre-industrial temperatures. RISES-AM aims to produce a better quantification of the impacts and vulnerabilities associated with these high end climate scenarios, and show that adaptation to them is possible at an affordable cost when compared to the increase in risk resulting from them. We investigated the physical and economic impact of extreme flood events of on the Mersey Estuary and surrounding areas. It is thought the Mersey Estuary is likely to be more sensitive to changes in forcing factors in the future than in the past where industrial impacts where the main drivers of change. Extreme events were simulated, for the present day and in 2100 where high impact emission scenarios have resulted in SLR ranging from 0.71 m to 1.80 m depending on the higher end emission scenario selected. If built, the barrage in the Estuary or lagoon in surrounding areas such as the

  1. Pollution Impacts on Bacterioplankton Diversity in a Tropical Urban Coastal Lagoon System

    Science.gov (United States)

    Salloto, Gigliola R. B.; Cardoso, Alexander M.; Coutinho, Felipe H.; Pinto, Leonardo H.; Vieira, Ricardo P.; Chaia, Catia; Lima, Joyce L.; Albano, Rodolpho M.; Martins, Orlando B.; Clementino, Maysa M.

    2012-01-01

    Despite a great number of published studies addressing estuarine, freshwater and marine bacterial diversity, few have examined urban coastal lagoons in tropical habitats. There is an increasing interest in monitoring opportunistic pathogens as well as indigenous microbial community members in these water bodies by current molecular and microbiological approaches. In this work, bacterial isolates were obtained through selective plate dilution methods to evaluate antibiotic resistances. In addition, 16S rRNA gene libraries were prepared from environmental waters and mixed cultures grown in BHI medium inoculated with Jacarepaguá lagoon waters. Denaturing gradient gel electrophoresis (DGGE) analyses showed distinct community profiles between environmental communities from each studied site and their cultured counterparts. A total of 497 bacterial sequences were analyzed by MOTHUR, yielding 245 operational taxonomic units (OTUs) grouped at 97% similarity. CCA diagrams showcased how several environmental variables affect the distribution of 18 bacterial orders throughout the three distinct habitats. UniFrac metrics and Venn diagrams revealed that bacterial communities retrieved through each experimental approach were significantly different and that only one OTU, closely related to Vibrio cholerae, was shared between them. Potentially pathogenic bacteria were isolated from most sampled environments, fifty percent of which showed antibiotic resistance. PMID:23226484

  2. Environmental influences on fish assemblage distribution of an estuarine coastal lagoon, Ria de Aveiro (Portugal

    Directory of Open Access Journals (Sweden)

    L. Pombo

    2005-03-01

    Full Text Available Fish assemblage was examined for patterns in spatial and seasonal structure within an estuarine coastal lagoon, Ria de Aveiro. Two years of variation in abiotic conditions were recorded to identify factors responsible for maintaining the structure of fish assemblages. Nine sites were sampled monthly with a traditional “chincha” beach-seine net between November 1998 and October 2000. Fish abundance and biomass changed significantly between sites. Temperature was found to be the most important abiotic factor affecting the abundance (number of fish distribution of fish assemblage, which is more related to seasonal migrations than to spatial migrations. Salinity was the most important abiotic factor affecting the fish biomass, with temperature also having a major influence. The other abiotic parameters analysed also showed some influence on the distribution of fish, although, isolated from the other controlled and/or uncontrolled factors, they could not fully explain all the differences between assemblages. Feeding analysis indicates that fish assemblage is mostly dependent on small benthic and pelagic crustaceans and/or detritus, although they can feed opportunistically on other prey. The low spatial segregation of fish in relation to feeding preference indicates that, in a food-rich lagoon such as Ria de Aveiro, the environmental-biological interactions appear to have a greater effect on fish distribution than do biological interactions.

  3. Macrobenthos of the coastal Budi Lagoon, southern Chile: Changes associated with seasonal environmental variation

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    Carlos Bertrán

    Full Text Available Abstract The purpose of the present study was to investigate the seasonal relationship of macrobenthos richness and abundance with sediment characteristics (i.e. texture and organic material for the coastal Budi Lagoon in southern Chile. Physicochemical measurements and macrobenthos samples were taken over the course of a year at nine sampling stations. Sandy-muddy sediment was the most common, and high percentages of organic material were registered, varying significantly between seasons and stations. The recorded organic material was related to natural (resident wild birds and anthropogenic (agriculture sources. Regarding fauna, 28 benthonic taxa and 7092 individuals were identified, with temporal and spatial variations. The most abundant taxa year-round were the molluscs Littoridina cumingii and Kingiella chilenica and the bristle worm Prionospio patagonica. Together, the obtained results evidence the important impact of organic material on the macrobenthos, with macrobenthic richness and abundance decreasing in conditions of high organic material content. The recorded variations for different taxa may indicate a response to the land use around the Budi Lagoon, which is intensely subjected to agricultural and tourist activities.

  4. Incidence of phytoplankton and environmental conditions on the bacterial ammonium uptake in a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Germán Pérez

    2014-03-01

    Full Text Available We analyzed the coupling between bacterioplankton and phytoplankton in Laguna de Rocha through an experimental approach. A freshwater zone of high turbidity and macrophytes growth and a brackish zone of higher light penetration and lower macrophytes biomass characterize this coastal lagoon. It has been shown that dissolved inorganic nitrogen, especially NH4+, has decreased to undetectable levels during the last decade. One hypothesis for this trend is the rapid removal by phytoplankton and bacterioplankton uptake. In an attempt to test this, we performed incubations using lagoon water from both zones split in two treatments (pre-filtered by 1.2 µm and unfiltered water and amended with 15N-NH4+. After 4 h incubation we found that in both zones bacterioplankton showed significantly higher NH4+ uptake rates when incubated together with phytoplankton and that uptake rates of both microbial communities were higher in freshwater incubations. These results suggest that bacterial NH4+ uptake would be coupled to phytoplankton-derived exudates and hence that depletion of dissolved NH4+ in this system could be linked to rapid microbial uptake. The degree of this coupling would vary according to hydrological dynamics in this ecosystem.

  5. Pollution impacts on bacterioplankton diversity in a tropical urban coastal lagoon system.

    Directory of Open Access Journals (Sweden)

    Gigliola R B Salloto

    Full Text Available Despite a great number of published studies addressing estuarine, freshwater and marine bacterial diversity, few have examined urban coastal lagoons in tropical habitats. There is an increasing interest in monitoring opportunistic pathogens as well as indigenous microbial community members in these water bodies by current molecular and microbiological approaches. In this work, bacterial isolates were obtained through selective plate dilution methods to evaluate antibiotic resistances. In addition, 16S rRNA gene libraries were prepared from environmental waters and mixed cultures grown in BHI medium inoculated with Jacarepaguá lagoon waters. Denaturing gradient gel electrophoresis (DGGE analyses showed distinct community profiles between environmental communities from each studied site and their cultured counterparts. A total of 497 bacterial sequences were analyzed by MOTHUR, yielding 245 operational taxonomic units (OTUs grouped at 97% similarity. CCA diagrams showcased how several environmental variables affect the distribution of 18 bacterial orders throughout the three distinct habitats. UniFrac metrics and Venn diagrams revealed that bacterial communities retrieved through each experimental approach were significantly different and that only one OTU, closely related to Vibrio cholerae, was shared between them. Potentially pathogenic bacteria were isolated from most sampled environments, fifty percent of which showed antibiotic resistance.

  6. Agrochemical loading in drains and rivers and its connection with pollution in coastal lagoons of the Mexican Pacific.

    Science.gov (United States)

    Arellano-Aguilar, Omar; Betancourt-Lozano, Miguel; Aguilar-Zárate, Gabriela; Ponce de Leon-Hill, Claudia

    2017-06-01

    The state of Sinaloa in Mexico is an industrialized agricultural region with a documented pesticide usage of 700 t year -1 ; which at least 17 of the pesticides are classified as moderately to highly toxic. Pollutants in the water column of rivers and drains are of great concern because the water flows into coastal lagoons and nearshore waters and thereby affects aquatic organisms. This study was done in four municipalities in the state of Sinaloa that produce food intensively. To investigate the link between pollution in the lagoons and their proximity to agricultural sites, water was sampled in three coastal lagoons and in the rivers and drains that flow into them. Seawater from the Gulf of California, 10 km from the coast, was also analyzed. Concentrations of nutrients, organochlorines, and organophosphorus pesticides were determined. Nutrient determination showed an unhealthy environment with N/P ratios of rivers, with ΣHCH showing the highest concentrations. In the southern part of the region studied, pollution of the coastal lagoon of Pabellones could be traced mainly to the drains from the agricultural sites. Accumulation of OC pesticides was also observed in the Gulf of California. Tests for 22 organophosphates revealed only five (diazinon, disulfoton, methyl parathion, chlorpyrifos, and mevinphos); diazinon was detected at all the sites, although methyl parathion was present at some sites at concentrations one order of magnitude higher than diazinon.

  7. ANWR progress report number FY84-6: Movement of molting oldsquaws within the Beaufort Sea coastal lagoons of Arctic National Wildlife Refuge, Alaska, 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the movement of molting oldsquaw within the Beaufort Sea Coastal lagoons of the Arctic National Wildlife Refuge, Alaska. During August, 1983, 16...

  8. Phytoplankton variation and its relation to nutrients and allochthonous organic matter in a coastal lagoon on the Gulf of Mexico

    Science.gov (United States)

    Aké-Castillo, José A.; Vázquez, Gabriela

    2008-07-01

    In tropical and subtropical zones, coastal lagoons are surrounded by mangrove communities which are a source of high quantity organic matter that enters the aquatic system through litter fall. This organic matter decomposes, becoming a source of nutrients and other substances such as tannins, fulvic acids and humic acids that may affect the composition and productivity of phytoplankton communities. Sontecomapan is a coastal lagoon located in the southern Gulf of Mexico, which receives abundant litter fall from mangrove. To study the phytoplankton composition and its variation in this lagoon from October 2002 to October 2003, we evaluated the concentrations of dissolved folin phenol active substances (FPAS) as a measure of plant organic matter, salinity, temperature, pH, O 2, N-NH 4+, N-NO 3-, P-PO 43-, Si-SiO 2, and phytoplanktonic cell density in different mangrove influence zones including the three main rivers that feed the lagoon. Nutrients concentrations depended on freshwater from rivers, however these varied seasonally. Concentrations of P-PO 43-, N-NH 4+ and FPAS were the highest in the dry season, when maximum mangrove litter fall is reported. Variation of these nutrients seemed to depend on the internal biogeochemical processes of the lagoon. Blooms of diatoms ( Skeletonema spp., Cyclotella spp. and Chaetoceros holsaticus) and dinoflagellates ( Peridinium aff. quinquecorne, Prorocentrum cordatum) occurred seasonally and in the different mangrove influence zones. The high cell densities in these zones and the occurrence of certain species and its ordination along gradient of FPAS in a canonical correspondence analysis, suggest that plant organic matter (i.e. mangrove influence) may contribute to phytoplankton dynamics in Sontecomapan lagoon.

  9. The white mullet (Mugil curema) as biological indicator to assess environmental stress in tropical coastal lagoons.

    Science.gov (United States)

    García-Gasca, Alejandra; Ríos-Sicairos, Julián; Hernández-Cornejo, Rubí; Cunha, Isabel; Gutiérrez, Jesús N; Plascencia-González, Héctor; de la Parra, Luz María García; Abad-Rosales, Selene; Betancourt-Lozano, Miguel

    2016-12-01

    Several coastal lagoons and estuaries in Mexico receive untreated domestic and industrial discharges which contain complex mixtures of contaminants. In order to assess the effects of chemical contamination, we used the White mullet (Mugil curema) as biological indicator. We worked in two estuaries located in Northwest Mexico: Urias (highly polluted) and Teacapan (less polluted, therefore used as reference site). We measured several endpoints at different levels of biological organization: vitellogenin transcription in males as biomarker of estrogenic contamination, as well as reproductive, morphological (deformities), morphometric, and meristic parameters. Total RNA was isolated from the liver, and a partial sequence of the mullet vitellogenin gene was obtained; gene expression was analyzed by quantitative PCR. At the same time, gonad samples were analyzed by histologic techniques to determine sex ratios and the reproductive cycle stage. The reproductive season was detected from February to June in both sites, but the gonadosomatic index was consistently higher in Teacapan. Sex ratios were female-biased in both estuaries, and one intersex gonad and several malformations were found in fish from Urias. Vitellogenin gene transcription in males was detected in both sites, although gene expression was slightly higher in Urias. The results obtained in this study indicate that biological effects of contamination are evident in fish, environmental estrogens may be present in both estuaries, and the white mullet is useful as biological indicator to identify and characterize environmental stressors in tropical coastal ecosystems.

  10. Highly diverse recombining populations of Vibrio cholerae and Vibrio parahaemolyticus in French Mediterranean coastal lagoons

    Science.gov (United States)

    Esteves, Kévin; Mosser, Thomas; Aujoulat, Fabien; Hervio-Heath, Dominique; Monfort, Patrick; Jumas-Bilak, Estelle

    2015-01-01

    Vibrio parahaemolyticus and Vibrio cholerae are ubiquitous to estuarine and marine environments. These two species found in Mediterranean coastal systems can induce infections in humans. Environmental isolates of V. cholerae (n = 109) and V. parahaemolyticus (n = 89) sampled at different dates, stations and water salinities were investigated for virulence genes and by a multilocus sequence-based analysis (MLSA). V. cholerae isolates were all ctxA negative and only one isolate of V. parahaemolyticus displayed trh2 gene. Most Sequence Types (ST) corresponded to unique ST isolated at one date or one station. Frequent recombination events were detected among different pathogenic species, V. parahaemolyticus, V. cholerae, Vibrio mimicus, and Vibrio metoecus. Recombination had a major impact on the diversification of lineages. The genetic diversity assessed by the number of ST/strain was higher in low salinity condition for V. parahaemolyticus and V. cholerae whereas the frequency of recombination events in V. cholerae was lower in low salinity condition. Mediterranean coastal lagoon systems housed V. cholerae and V. parahaemolyticus with genetic diversities equivalent to the worldwide diversity described so far. The presence of STs found in human infections as well as the frequency of recombination events in environmental vibrios populations could predict a potential epidemiological risk. PMID:26236294

  11. Effects of organic pollution and physical stress on benthic macroinvertebrate communities from two intermittently closed and open coastal lagoons (ICOLLs)

    Science.gov (United States)

    Coelho, Susana; Pérez-Ruzafa, Angel; Gamito, Sofia

    2015-12-01

    Benthic macroinvertebrate communities and environmental conditions were studied in two intermittently closed and open coastal lakes and lagoons (ICOLLs), located in southern Algarve (Foz do Almargem e Salgados), with the purpose of evaluating the effects of organic pollution, originated mainly from wastewater discharges, and the physical stress caused by the irregular opening of the lagoons. Most of the year, lagoons were isolated from the sea, receiving the freshwater inputs from small rivers and in Salgados, also from the effluents of a wastewater plant. According to environmental and biotic conditions, Foz do Almargem presented a greater marine influence and a lower trophic state (mesotrophic) than Salgados (hypereutrophic). Benthic macroinvertebrate communities in the lagoons were distinct, just as their relations with environmental parameters. Mollusca were the most abundant macroinvertebrates in Foz do Almargem, while Insecta, Oligochaeta and Crustacea were more relevant in Salgados. Corophium multisetosum occurred exclusively in Salgados stations and, just as Chironomus sp., other Insecta and Oligochaeta, densities were positively related to total phosphorus, clay content and chlorophyll a concentration in the sediment, chlorophyll a concentration in water and with total dissolved inorganic nitrogen. Abra segmentum, Cerastoderma glaucum, Peringia ulvae and Ecrobia ventrosa occurred only in Foz do Almargem, with lower values of the above mentioned parameters. Both lagoons were dominated by deposit feeders and taxa tolerant to environmental stress, although in Salgados there was a greater occurrence of opportunistic taxa associated to pronounced unbalanced situations, due to excess organic matter enrichment.

  12. Assessing the ecological status of Mediterranean coastal lagoons using macroinvertebrates. Comparison of the most commonly used methods

    Directory of Open Access Journals (Sweden)

    S. REIZOPOULOU

    2014-09-01

    Full Text Available Benthic communities were studied twice (autumn and spring in three Mediterranean coastal lagoons located in Greece (Logarou and Italy (Cesine and Grado-Marano. The species composition and distribution, the community diversity, the species richness, the dominant taxa and their ecological identity, the benthic trophic and biomass size structure were investigated in these lagoons and the the results were correlated with environmental variables.The overall similarity based on species composition and abundance among lagoons was low due to differences in dominant environmental factors, whereas variations of community diversity and species richness were mainly related to the degree of marine influence, reflecting the natural structure. The benthic classification indices AMBI, M-AMBI, BENTIX, BO2A, ISD and ISS were applied to assess the ecological status of the lagoons studied. Results showed that the biotic indices AMBI, M-AMBI, BENTIX, and BO2A are not adequately efficient due to the natural dominance of tolerant and opportunistic species and the correlation of species diversity to natural stress. ISD and ISS on the other hand, based on size distribution frequencies and on size spectra sensitivity respectively, had a good discrimination power between impacted and unimpacted sites. Results indicate that alternatively to the species sensitivity, other traits of the communities as the biomass or size structure could be more robust, sensitive and effective in assessing the ecological quality in lagoons.

  13. Spatial distribution and biomass of aquatic rooted macrophytes and their relevance in the metabolism of a Mediterranean coastal lagoon

    Directory of Open Access Journals (Sweden)

    Biel Obrador

    2007-03-01

    Full Text Available This work aims to characterise the current autotrophic compartment of the Albufera des Grau coastal lagoon (Menorca, Balearic Islands and to assess the relationship between the submerged macrophytes and the limnological parameters of the lagoon. During the study period the submerged vegetation was dominated by the macrophyte Ruppia cirrhosa, which formed dense extensive meadows covering 79% of the surface. Another macrophyte species, Potamogeton pectinatus, was also observed but only forming small stands near the rushing streams. Macroalgae were only occasionally observed. Macrophyte biomass showed a clear seasonal trend, with maximum values in July. The biomass of R. cirrhosa achieved 1760 g DW m-2, the highest biomass ever reported for this species in the literature. The seasonal production-decomposition cycle of the macrophyte meadows appears to drive the nutrient dynamics and carbon fluxes in the lagoon. Despite the significant biomass accumulation and the absence of a washout of nutrients and organic matter to the sea, the lagoon did not experience a dystrophic collapse. These results indicate that internal metabolism is more important than exchange processes in the lagoon.

  14. The effect of floods on sediment contamination in a microtidal coastal lagoon: the lagoon of Lesina, Italy.

    Science.gov (United States)

    D'Adamo, Raffaele; Specchiulli, Antonietta; Cassin, Daniele; Botter, Margherita; Zonta, Roberto; Fabbrocini, Adele

    2014-10-01

    The effects on the microtidal lagoon of Lesina of runoff and the discharge of water and material from agricultural activities were investigated combining chemical analyses of pollutants [11 metals and 16 priority polycyclic aromatic compounds (PAHs)], determination of organic matter and grain size, and performance of innovative ecotoxicological tests. For metals, enrichment factors >3 for arsenic, nickel, and copper (Cu) were observed in the eastern zone of the lagoon, which is affected by nearby urban activities with discharge of water and domestic waste and by agricultural input with waters rich in fertilizers. Cu was correlated with no other metal, and its high concentrations (≤77 µg g(-1)) may result from the use of Cu-based fungicides in vineyards. Total PAHs (2,230 ± 3,150 ng g(-1)) displayed a wide range of concentrations with hot spots near freshwater inputs from the part of the catchment area exploited for wheat crops. Pyrolitic contamination also emerged, with higher-mass PAH congeners, such as asphalt, bitumen or coal, usually present in higher fractions as the dominant components. Ecotoxicological evaluations recorded moderate to high toxicity levels; the innovative MOT test bioassay showed good discriminatory ability because it identified a lagoon area whose inputs mainly depend on agricultural activities and which is impacted by metals rather than PAHs. Floods during periods of heavy rain and the discharge of water and material from agricultural activities may impact vulnerable systems, such as the lagoon of Lesina, where the presence of hot spots with remarkably high pollution values was observed.

  15. Anthropogenic regulation of the phosphorus balance in the Thau catchment-coastal lagoon system (Mediterraean Sea, France) over 24 years.

    Science.gov (United States)

    La Jeunesse, I; Elliott, M

    2004-04-01

    In the Thau lagoon, despite there being no phosphate limitation policy, the annual mean phosphate concentrations decreased by 90% between 1971 and 1994. The present study indicates a relationship between the decrease of phosphate concentrations and changes in urban, industrial and agricultural activities within the catchment generating phosphorus (P) inputs; and shellfish farming leading to phosphorus storage and export. The relationship (tonnes of P) is: P-PO(4)(3-) in the lagoon waters=1.0124 anthropogenic phosphorus balance--47.62 (r(2) = 0.824, p < 0.000). As population growth is expected in coastal zones, sustainable development requires the need for addressing the role played by human activities and the multi-scale regulation of them. As an element of integrated coastal zone management, the present study provides a regional scale analysis of these aspects.

  16. Effects of land use changes on eutrophication indicators in five coastal lagoons of the Southwestern Atlantic Ocean

    Science.gov (United States)

    Rodríguez-Gallego, Lorena; Achkar, Marcel; Defeo, Omar; Vidal, Leticia; Meerhoff, Erika; Conde, Daniel

    2017-03-01

    Five catchment areas in Uruguay were selected to conduct a nutrient exportation analysis and to evaluate the effects of current land use on the eutrophication of coastal lagoons. Satellite images and national agriculture censuses were used for a quantitative analysis of land use changes from 1974 to 2005, and a nutrient export coefficient approximation was used to determine long-term changes in annual loads. Several eutrophication indicators (water, sediment and autotrophic communities) were assessed seasonally in the lagoon basins during 2005 and 2006. The areal annual load of nutrients exported to the lagoons increased over time. Population and extensive livestock ranching were the most important nutrient sources, while agriculture is increasing in importance. Buffer effects of riparian forests on eutrophication indicators were observed in contrast to the wetlands surrounding the lagoons, which seem to be acting as a source of nutrients. Catchment size was inversely related to most eutrophication indicators. Afforestation and agriculture were found not to directly impact eutrophication indicators, however, catchments with larger agricultural areas showed higher concentrations of suspended solids, which may indicate the export of particulate nutrients. Salinity was inversely related to most eutrophication indicators, suggesting that the manipulation of the sand bar of the lagoons is a critical management issue. Sediment-related eutrophication indicators were more sensitive to changes in land uses and covers, in contrast with the more variable water column indicators, suggesting their potential use as enduring indicators. This research provides a rapid and integral assessment for qualitatively linking catchment changes with eutrophication indicators in coastal environments, which can easily be replicated to track pollutants in locations that lack standardized monitoring programs needed for more complex catchment modeling approaches.

  17. Heterotrophic microbial activity and organic matter degradation in coastal lagoons of Colombia

    Directory of Open Access Journals (Sweden)

    Klaus Gocke

    2003-03-01

    Full Text Available In this study we measured the community respiration and the bacterial respiration as part of the overall degradation process of organic material. Additionally, the turnover rates of the pools of dissolved free glucose and acetate as representatives of the fraction of easily degradable low molecular organic solutes were determined. The study was performed in several coastal lagoons of the "Outer Delta of the Río Magdalena" in northern Colombia. The lagoons can be separated into two groups: The first group contains highly productive brackish lagoons with chl a concentrations ranging from 62 - 130 µg/l. The second group consists of less productive freshwater lagoons with chl a between 5.5 - 19 µg/l. Turnover rates of glucose and acetate were very fast in the highly productive lagoons resulting in turnover times of less than 20 min for both compounds. In the less productive systems the cycling of glucose and acetate was much slower. Here the mean values of the turnover times were 2 hr for glucose and 1.5 hr for acetate. The rates of bacterial DNA-formation measured as thymidine incorporation differed significantly between both groups of lagoons, being very high (1.86 - 2.76 nmol/l/hr in the highly productive and relatively low (0.073 - 0.55 nmol/l/hr in the less productive group. Water column community respiration ranged between 122 and 16 µg C/l/hr with means of 88 µg C/l/hr in the highly and 19 µg C/l/hr in the less productive group. In the first group the mean values of the bacterial contribution to community respiration amounted to 37% and in the second group to 18%. The bacterial respiration was determined in an indirect way via bacterial biomass production and assuming a growth efficiency of 50%. It is discussed whether this relatively high growth efficiency allows reasonable results in both groups of lagoons.Este estudio midió la respiración de la comunidad planctónica y la respiración bacteriana como parte del proceso de degradaci

  18. Phenology of cryptomonads and the CRY1 lineage in a coastal brackish lagoon (Vistula Lagoon, Baltic Sea).

    Science.gov (United States)

    Piwosz, Kasia; Kownacka, Janina; Ameryk, Anetta; Zalewski, Mariusz; Pernthaler, Jakob

    2016-08-01

    Cryptomonadales have acquired their plastids by secondary endosymbiosis. A novel clade-CRY1-has been discovered at the base of the Cryptomonadales tree, but it remains unknown whether it contains plastids. Cryptomonadales are also an important component of phytoplankton assemblages. However, they cannot be readily identified in fixed samples, and knowledge on dynamics and distribution of specific taxa is scarce. We investigated the phenology of the CRY1 lineage, three cryptomonadales clades and a species Proteomonas sulcata in a brackish lagoon of the Baltic Sea (salinity 0.3-3.9) using fluorescence in situ hybridization. A newly design probe revealed that specimens of the CRY1 lineage were aplastidic. This adds evidence against the chromalveolate hypothesis, and suggests that the evolution of cryptomonadales' plastids might have been shorter than is currently assumed. The CRY1 lineage was the most abundant cryptomonad clade in the lagoon. All of the studied cryptomonads peaked in spring at the most freshwater station, except for P. sulcata that peaked in summer and autumn. Salinity and concentration of dissolved inorganic nitrogen most significantly affected their distribution and dynamics. Our findings contribute to the ecology and evolution of cryptomonads, and may advance understanding of evolutionary relationships within the eukaryotic tree of life. © 2016 Phycological Society of America.

  19. Mercury speciation and transport via submarine groundwater discharge at a southern California coastal lagoon system

    Science.gov (United States)

    Ganguli, P.M.; Conaway, C.H.; Swarzenski, P.W.; Izbicki, J.A.; Flegal, A.R.

    2012-01-01

    We measured total mercury (Hg T) and monomethylmercury (MMHg) concentrations in coastal groundwater and seawater over a range of tidal conditions near Malibu Lagoon, California, and used 222Rn-derived estimates of submarine groundwater discharge (SGD) to assess the flux of mercury species to nearshore seawater. We infer a groundwater-seawater mixing scenario based on salinity and temperature trends and suggest that increased groundwater discharge to the ocean during low tide transported mercury offshore. Unfiltered Hg T (U-Hg T) concentrations in groundwater (2.2-5.9 pM) and seawater (3.3-5.2 pM) decreased during a falling tide, with groundwater U-Hg T concentrations typically lower than seawater concentrations. Despite the low Hg T in groundwater, bioaccumulative MMHg was produced in onshore sediment as evidenced by elevated MMHg concentrations in groundwater (0.2-1 pM) relative to seawater (???0.1 pM) throughout most of the tidal cycle. During low tide, groundwater appeared to transport MMHg to the coast, resulting in a 5-fold increase in seawater MMHg (from 0.1 to 0.5 pM). Similarly, filtered Hg T (F-Hg T) concentrations in seawater increased approximately 7-fold during low tide (from 0.5 to 3.6 pM). These elevated seawater F-Hg T concentrations exceeded those in filtered and unfiltered groundwater during low tide, but were similar to seawater U-Hg T concentrations, suggesting that enhanced SGD altered mercury partitioning and/or solubilization dynamics in coastal waters. Finally, we estimate that the SGD Hg T and MMHg fluxes to seawater were 0.41 and 0.15 nmol m -2 d -1, respectively - comparable in magnitude to atmospheric and benthic fluxes in similar environments. ?? 2012 American Chemical Society.

  20. Effects of Submerged Aquatic Vegetation on Macrobenthos in a Coastal Lagoon of the Southwestern Atlantic

    Science.gov (United States)

    Arocena, R.

    2005-05-01

    The northern, freshwater-dominated, edge of Rocha coastal lagoon in Uruguay, South America, was invaded during recent years by submerged aquatic vegetation (SAV). To evaluate the effect of SAV on the composition and abundance of macrozoobenthos, I compared this assemblage between a site that was vegetated in summer-autumn (V) to another one that was always bare (N). Only station V often showed thermal stratification, due to a reduction in water circulation caused by the plants (Potamogeton, Cabomba, Myriophyillum, Ruppia). Both sites had similar water quality and sediment characteristics (70 % sand, 30 % silt). I found a total of 28 benthic taxa: 3 species of Polychaeta, 2 of Mollusca, 3 of Crustacea and 20 genera of Insecta. Taxon richness and total abundance of invertebrates, as well as individual abundance of amphipods, gastropods and chironomids were significantly higher at V compared with N. Conversely, the crustacean Tanais stanfordi, the clam Erodona mactroides and the polychaete Laeonereis culveri were significantly more abundant at the unvegetated site. Moreover, Shannon diversity was higher at N than at V. These results show that the colonization by plants may enhance the variety and the abundance of benthos.

  1. Anthropogenic shift of planktonic food web structure in a coastal lagoon by freshwater flow regulation

    Science.gov (United States)

    Hemraj, Deevesh A.; Hossain, A.; Ye, Qifeng; Qin, Jian G.; Leterme, Sophie C.

    2017-03-01

    Anthropogenic modification of aquatic systems has diverse impacts on food web interactions and ecosystem states. To reverse the adverse effects of modified freshwater flow, adequate management of discharge is required, especially due to higher water requirements and abstractions for human use. Here, we look at the effects of anthropogenically controlled freshwater flow regimes on the planktonic food web of a Ramsar listed coastal lagoon that is under recovery from degradation. Our results show shifts in water quality and plankton community interactions associated to changes in water flow. These shifts in food web interactions represent modifications in habitat complexity and water quality. At high flow, phytoplankton-zooplankton interactions dominate the food web. Conversely, at low flow, bacteria, viruses and nano/picoplankton interactions are more dominant, with a substantial switch of the food web towards heterotrophy. This switch can be associated with excess organic matter loading, decomposition of dead organisms, and synergistic and antagonistic interactions. We suggest that a lower variability in flow amplitude could be beneficial for the long-term sustaining of water quality and food web interactions, while improving the ecosystem health of systems facing similar stresses as the Coorong.

  2. Trace Elements and Carbon and Nitrogen Stable Isotopes in Organisms from a Tropical Coastal Lagoon

    Science.gov (United States)

    van Hattum, B.; de Boer, J.; van Bodegom, P. M.; Rezende, C. E.; Salomons, W.

    2010-01-01

    Trace elements (Fe, Mn, Al, Zn, Cr, Cu, Ni, Pb, Cd, Hg, and As) and stable isotope ratios (δ13C and δ15N) were analyzed in sediments, invertebrates, and fishes from a tropical coastal lagoon influenced by iron ore mining and processing activities to assess the differences in trace element accumulation patterns among species and to investigate relations with trophic levels of the organisms involved. Overall significant negative relations between trophic level (given by 15N) and trace element concentrations in gastropods and crustaceans showed differences in internal controls of trace element accumulation among the species of different trophic positions, leading to trace element dilution. Generally, no significant relation between δ15N and trace element concentrations was observed among fish species, probably due to omnivory in a number of species as well as fast growth. Trace element accumulation was observed in the fish tissues, with higher levels of most trace elements found in liver compared with muscle and gill. Levels of Fe, Mn, Al, and Hg in invertebrates, and Fe and Cu in fish livers, were comparable with levels in organisms and tissues from other contaminated areas. Trace element levels in fish muscle were below the international safety baseline standards for human consumption. PMID:20217062

  3. Trematode communities in snails can indicate impact and recovery from hurricanes in a tropical coastal lagoon.

    Science.gov (United States)

    Aguirre-Macedo, María Leopoldina; Vidal-Martínez, Victor M; Lafferty, Kevin D

    2011-11-01

    In September 2002, Hurricane Isidore devastated the Yucatán Peninsula, Mexico. To understand its effects on the parasites of aquatic organisms, we analyzed long-term monthly population data of the horn snail Cerithidea pliculosa and its trematode communities in Celestún, Yucatán, Mexico before and after the hurricane (February 2001 to December 2009). Five trematode species occurred in the snail population: Mesostephanus appendiculatoides, Euhaplorchis californiensis, two species of the genus Renicola and one Heterophyidae gen. sp. Because these parasites use snails as first intermediate hosts, fishes as second intermediate hosts and birds as final hosts, their presence in snails depends on food webs. No snails were present at the sampled sites for 6 months after the hurricane. After snails recolonised the site, no trematodes were found in snails until 14 months after the hurricane. It took several years for snail and trematode populations to recover. Our results suggest that the increase in the occurrence of hurricanes predicted due to climate change can impact upon parasites with complex life cycles. However, both the snail populations and their parasite communities eventually reached numbers of individuals and species similar to those before the hurricane. Thus, the trematode parasites of snails can be useful indicators of coastal lagoon ecosystem degradation and recovery. Copyright © 2011 Australian Society for Parasitology Inc. All rights reserved.

  4. Diet of the clupeid fish Platanichthys platana (Regan, 1917 in two different Brazilian coastal lagoons

    Directory of Open Access Journals (Sweden)

    Aguiaro Talita

    2003-01-01

    Full Text Available Platanichthys platana is considered a constant species in both Cabiúnas and Imboassica lagoons that are characterised by different marine and freshwater inputs, and anthropogenic influences. The stomach content analysis of P. platana captured between July 1991 and July 1993 revealed filamentous algae, detritus, eggs of benthic invertebrates, larvae of chironomids and bivalves as the main food sources in Imboassica lagoon. Small-sized cladocerans, copepods and shrimp larvae were the prevailing items in Cabiúnas lagoon. Seasonal food variations were noted for the fishes of Imboassica lagoon. Diet differences were highlighted within specimens lesser than 40 mm standard length in Imboassica lagoon, and were related to the increase of marine influence due to artificial sand barrier openings. Dissimilarities among size classes in relation to invertebrate larvae consumption were observed in fishes from Cabiúnas lagoon.

  5. Evidence for limited exchange of avian influenza viruses between seaducks and dabbling ducks at Alaska Peninsula coastal lagoons

    Science.gov (United States)

    Ramey, Andy M.; Pearce, John M.; Reeves, A.B.; Franson, J. Christian; Petersen, Margaret R.; Ip, Hon S.

    2011-01-01

    Avian influenza virus (AIV) prevalence and sequence data were analyzed for Steller's eiders (Polysticta stelleri) to assess the role of this species in transporting virus genes between continents and maintaining a regional viral reservoir with sympatric northern pintails (Anas acuta). AIV prevalence was 0.2% at Izembek Lagoon and 3.9% at Nelson Lagoon for Steller's eiders and 11.2% for northern pintails at Izembek Lagoon. Phylogenetic analysis of 13 AIVs from Steller's eiders revealed that 4.9% of genes were of Eurasian origin. Seven subtypes were detected, including two also observed in northern pintails. No AIV strains were highly similar (> 99%) at all gene segments between species; however, highly similar individual genes were detected. The proportion of highly similar genes was greater within rather than between species. Steller's eiders likely transport AIV genes between continents through long-distance migratory movements. Differences in AIV prevalence, subtype distribution, and the proportion of highly similar genes suggest limited AIV exchange between Steller's eiders and northern pintails at Alaska Peninsula coastal lagoons during autumn.

  6. High prevalence of cattle fascioliasis in coastal areas of Thua Thien Hue province, Vietnam.

    Science.gov (United States)

    Nguyen, Nga Thi; LE, Thinh Cong; Vo, Minh Duc Co; VAN Cao, Hoang; Nguyen, Ly Thi; Ho, Khanh Thi; Nguyen, Quyet Ngoc; Tran, Vui Quang; Matsumoto, Yasunobu

    2017-06-16

    In Vietnam, especially central Vietnam, patients with fascioliasis are increasingly being reported. Since the fascioliasis is zoonotic, survey on the cattle fascioliasis should be informative for the control of human fascioliasis. In this study, the prevalence of cattle fascioliasis as well as the density of the intermediate host snails, Lymnaea swinhoei and L. viridis, were studied in Thua Thien Hue (TTH) province during 2014-2015. A total of 572 cattle feces were examined from 27 communes in 9 districts. Fasciola eggs were detected in cattle from 24 communes with an average prevalence of 23.4% (134/ 572). The highest prevalence was detected in cattle in the coastal plain terrain (31.0%) followed by plain (25.5%), mountain (21.7%), and low hilly (16.2%) terrains. The highest proportion of heavy infection (>200 EPG) was observed in the coastal plain terrain (36.1%), followed by mountains (20.0%), low hills (13.0%), and plains (8.9%). Low number of heavy infection, as well as relatively low prevalence in low hills and plains were associated with the extensive use of anti-fluke treatments. High number of intermediate host snails in low hilly and plain terrains also indicate high risk of fascioliasis. In this study, the density of Lymnaea snails in the coastal plain terrain was found to be very high (17.3 snails/m 2 ) compared to that in previous studies. This is the first report indicating the recent expansion of cattle fascioliasis in the coastal region in Vietnam.

  7. An integrated Pan-European perspective on coastal Lagoons management through a mosaic-DPSIR approach

    Science.gov (United States)

    Dolbeth, Marina; Stålnacke, Per; Alves, Fátima L.; Sousa, Lisa P.; Gooch, Geoffrey D.; Khokhlov, Valeriy; Tuchkovenko, Yurii; Lloret, Javier; Bielecka, Małgorzata; Różyński, Grzegorz; Soares, João A.; Baggett, Susan; Margonski, Piotr; Chubarenko, Boris V.; Lillebø, Ana I.

    2016-01-01

    A decision support framework for the management of lagoon ecosystems was tested using four European Lagoons: Ria de Aveiro (Portugal), Mar Menor (Spain), Tyligulskyi Liman (Ukraine) and Vistula Lagoon (Poland/Russia). Our aim was to formulate integrated management recommendations for European lagoons. To achieve this we followed a DPSIR (Drivers-Pressures-State Change-Impacts-Responses) approach, with focus on integrating aspects of human wellbeing, welfare and ecosystem sustainability. The most important drivers in each lagoon were identified, based on information gathered from the lagoons’ stakeholders, complemented by scientific knowledge on each lagoon as seen from a land-sea perspective. The DPSIR cycles for each driver were combined into a mosaic-DPSIR conceptual model to examine the interdependency between the multiple and interacting uses of the lagoon. This framework emphasizes the common links, but also the specificities of responses to drivers and the ecosystem services provided. The information collected was used to formulate recommendations for the sustainable management of lagoons within a Pan-European context. Several common management recommendations were proposed, but specificities were also identified. The study synthesizes the present conditions for the management of lagoons, thus analysing and examining the activities that might be developed in different scenarios, scenarios which facilitate ecosystem protection without compromising future generations.

  8. Endocrine-disrupting chemicals in coastal lagoons of the Po River delta: sediment contamination, bioaccumulation and effects on Manila clams.

    Science.gov (United States)

    Casatta, Nadia; Stefani, Fabrizio; Pozzoni, Fiorenzo; Guzzella, Licia; Marziali, Laura; Mascolo, Giuseppe; Viganò, Luigi

    2016-06-01

    The large estuary that the River Po forms at its confluence into the Adriatic Sea comprises a multitude of transitional environments, including coastal lagoons. This complex system receives the nutrients transported by the River Po but also its load of chemical contaminants, which may pose a substantial (eco)toxicological risk. Despite the high ecological and economic importance of these vulnerable environments, there is a substantial lack of information on this risk. In light of the recent amendments of the European Water Framework Directive (2013/39/EU), the present study investigated the sediment contamination of six coastal lagoons of the Po delta and its effects on Manila clams (Ruditapes philippinarum), exposed in situ for 3 months. Sediment contamination and clam bioaccumulation of a wide range of chemicals, i.e. trace metals (Cd, Cr, Ni, Hg, Pb, As), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), organochlorine compounds (PCBs, DDTs), polycyclic aromatic hydrocarbons (PAHs) and organotins (TPhT, TBT), suggested a southward increase related to the riverine transports. Where the River Po influence was more direct, the concentrations of contaminants were higher, with nonylphenol and BDE-209 exceeding sediment quality guidelines. Biometric indicators suggested the influence of contamination on organism health; an inverse relationship between PBDEs in sediments and clam condition index has been found, as well as different biota-sediment accumulation factors (BSAFs) in the lagoons.

  9. Stability and bistability of seagrass ecosystems in shallow coastal lagoons: Role of feedbacks with sediment resuspension and light attenuation

    Science.gov (United States)

    Carr, J.; D'Odorico, P.; McGlathery, K.; Wiberg, P.

    2010-09-01

    Shallow coastal lagoons are environments where a dynamic equilibrium exists between water quality and seagrass cover. Dense seagrass canopies limit the resuspension of bed sediments thereby creating a clearer water column and a positive feedback for seagrass growth. Positive feedbacks are often associated with the existence of bistable dynamics in ecosystems. For example, a bare and a seagrass covered sediment bed could both be stable states of the system. This study describes a one-dimensional hydrodynamic model of vegetation-sediment-water flow interactions and uses it to investigate the strengths of positive feedbacks between seagrass cover, stabilization of bed sediments, turbidity of the water column, and the existence of a favorable light environment for seagrasses. The model is applied to Hog Island Bay, a shallow coastal lagoon on the eastern shore of Virginia. The effects of temperature, eutrophication, and bed grain size on bistability of seagrass ecosystems in the lagoon are explored. The results indicate that under typical conditions, seagrass is stable in water depths sustain seagrass. Decreases in sediment size and increases in water temperature and degree of eutrophication shift the bistable range to shallower depths, with more of the bay bottom unable to sustain seagrass.

  10. Fish composition and prey utilization of the black skimmer (Rynchops niger in mar Chiquita coastal lagoon, Argentina

    Directory of Open Access Journals (Sweden)

    Rocío Mariano-Jelicich

    2014-03-01

    Full Text Available Lagoons along the western coast of the South Atlantic Ocean shelter high densities of juvenile fish and are key areas for several seabirds that rely on the resources offered by this kind of ecosystem. The objective of this study was to analyze fish composition and abundance in shallow-water areas of the estuarine region of Mar Chiquita Coastal Lagoon (Argentina and the diet composition of the Black skimmer (Rynchops niger during its non-breeding season as well as evaluating its inter-annual variations. Fish were sampled with a beach-seine net and the skimmers' diet was analyzed from their pellets. The estuarine-dependent marine fishes were the best represented bio-ecological category followed by freshwater fishes. Significant differences were observed in fish abundance and composition between and within years. Species richness was higher during the summer season and during the first year sampled. The occurrence of freshwater fishes as an important and diverse group of the Mar Chiquita estuarine area contrasted with previous reports. The diet of the Black skimmer included freshwater, estuarine and marine fish species. Skimmers forage in the shallow waters of the estuarine area of the Mar Chiquita Coastal lagoon though little similarity was observed between its diet and local fish abundance. These results emphasize the importance of performing these evaluations in order to improve the quality of studies and the interpretations of top predators foraging ecology.

  11. Photoalteration of macrophyte-derived chromophoric dissolved organic matter induces growth of single bacterial populations in a coastal lagoon

    Directory of Open Access Journals (Sweden)

    Claudia Piccini

    2013-10-01

    Full Text Available Photochemical degradation is an important process involved in the decay of macrophytes, but little is known on the response of heterotrophic bacteria to the chromophoric dissolved organic matter (CDOM derived from different plant species. Here, we assessed the effect of photoaltered CDOM derived from Schoenoplectus californicus and Ruppia maritima on the composition and production of a bacterial community from a productive subtropical coastal lagoon. Chromophoric dissolved organic matter from plants extracts was characterised by optical methods before and after exposure to natural full solar radiation. Afterwards, bacteria from the lagoon were added and incubated in these extracts for 5 h. We found that CDOM from the plant extracts underwent photoalteration after exposure to natural solar radiation, inducing shifts in the original bacterial community composition. In both macrophyte extracts, the bacterial community significantly changed and became dominated by two populations with distinctive morphology. The main enriched bacteria in both plant extracts were large filaments that made up to 99% of the community biovolume. In the R. maritima extract, another type of enriched bacteria was detected, consisting of large rods. 16S rDNA sequencing showed that the enriched bacterial populations belonged to Exiguobacterium sp. (filaments and Acinetobacter sp. (rods. Morphotype identities were confirmed by fluorescence in situ hybridisation using specific probes targeting those taxa. Our results suggest that solar-induced photoalteration of plant material in this coastal lagoon results in the growth of opportunistic bacterial taxa.

  12. Impact of dredging in a shallow coastal lagoon: Microtox Basic Solid-Phase Test, trace metals and Corophium bioassay.

    Science.gov (United States)

    Guerra, R; Pasteris, A; Ponti, M; Fabbri, D; Bruzzi, L

    2007-05-01

    The aim of this work was to measure survival of the amphipod Corophium insidiosum and luminescence inhibition in the marine bacterium Vibrio fisheri on surface sediment samples collected from a shallow coastal lagoon (Pialassa Baiona, northern Adriatic Italian coast) before execution of dredging operations to deepen the main inner channel of the lagoon and restore the water circulation. Trace metal (Cd, Cu, Cr, Hg, Ni, Pb) concentrations, grain size and organic carbon matter content as loss of ignition were also measured. Toxicity testing with V. fisheri was carried out according to the Microtox Basic Solid-Phase Test (BSPT) protocol. The preliminary outcomes of this work show that: (a) the investigated area can be categorised as moderately degraded; (b) there is no evident spatial pattern in sediment toxicity and trace metal concentrations; (c) Microtox responses are not biased by sediment characteristics such as silt, clay and organic matter content.

  13. Phenology of cryptomonads and the CRY1 lineage in a coastal brackish lagoon (Vistula Lagoon, Baltic Sea)

    Czech Academy of Sciences Publication Activity Database

    Piwosz, Kasia; Kownacka, J.; Ameryk, A.; Zalewski, M.; Pernthalter, J.

    2016-01-01

    Roč. 52, č. 4 (2016), s. 626-637 ISSN 0022-3646 R&D Projects: GA ČR GA13-11281S Institutional support: RVO:61388971 Keywords : Baltic Sea * chromalveolate hypothesis * coastal waters Subject RIV: EE - Microbiology, Virology Impact factor: 2.608, year: 2016

  14. Hydrological behavior of coastal lagoons associated to wetlands, an example from southernmost bahía Samborombón (Argentina).

    Science.gov (United States)

    Tejada Tejada, Macarena; Carol, Eleanora; Galliari, Julieta; Richiano, Sebastian

    2017-04-01

    Coastal wetlands are located at a critical interface between the terrestrial and marine environments and are ideally positioned to reduce impacts from land-based sources. At the southern region of Bahía Samborombón (Argentina) the wetlands includes several small coastal lagoons developed inside of a sandy spike. The main object of this work is to analyze the hydrological behavior of the lagoons evaluating their role in the maintenances of the wetland. In order to do this, satellite image analysis was performed to identify the marshy areas, drainage features, morphology and connections of the lagoons, both with the tidal flows from the Río de la Plata estuary and from the Argentine Sea. Field surveys were carried out in one of the lagoons to define their geological and geomorphological characteristics. After that, a monitoring network was designed for sampling the superficial and the underground water, additionally electrical conductivity and pH of the water were determined in situ. In all the water samples extracted the content of majority ions was determined by standard methods. Complementary, sedimentological and malacological aspects were observed at several stations in the lagoon. The obtained results allow us to recognize that the tidal flow that enters from the sea, at least in the studied lagoon, is the main hydrological sustenance of the wetland. This flow enters mainly using one tidal channel which connects (in a semi-permanent way) the sea with the lagoon during extraordinary tide and storm events. During low tide the lagoon loses connection and the drainage towards the sea is scarce. The tidal water that accumulates in the lagoon is subsequently evaporated causing an increase in the salinity of the surface water to values higher than the sea. Groundwater that accumulates through the infiltration of rainfall in the sandy sediments of the spike also discharges to the lagoon and supports the wetland surrounding the coastal lagoon. This flow, even when it

  15. Vietnam

    International Development Research Centre (IDRC) Digital Library (Canada)

    Cathy Egan

    Meanwhile, IDRC was gathering advice and insights from other donors (including United Nations agencies) already active in. Vietnam. The information gathering ... preparation of young scholars and researchers. It was cooperating with other donors — many of them network partners with IDRC in other countries. Its gov-.

  16. Submarine groundwater discharge in a subsiding coastal lowland: A {sup 226}Ra and {sup 222}Rn investigation in the Southern Venice lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Gattacceca, Julie C., E-mail: jcg54@esc.cam.ac.uk [CEREGE, Aix-Marseille Universite, UMR 6635 CNRS-IRD-CDF, Europole Mediterraneen de l' Arbois, BP80, 13545 Aix en Provence (France); Mayer, Adriano [IDPA-CNR, Via Mario Bianco 9, 20131 Milano (Italy); Cucco, Andrea [Coastal Oceanography, CNR-IAMC, Oristano Unit, Loc. Sa MArdini, 09072 Oristano (Italy); Claude, Christelle; Radakovitch, Olivier; Vallet-Coulomb, Christine; Hamelin, Bruno [CEREGE, Aix-Marseille Universite, UMR 6635 CNRS-IRD-CDF, Europole Mediterraneen de l' Arbois, BP80, 13545 Aix en Provence (France)

    2011-05-15

    Highlights: > Occurence/magnitude of submarine groundwater discharge investigated in Venice lagoon (Italy) using {sup 226}Ra and {sup 222}Rn isotopic tracers. > Single box mass balance compared with multi boxes mass balance coupled with hydrodynamic model. > Groundwater flux accounts for 1% of lagoon hydrological balance (1-3 times surface runoff) and 30-50% of tracers inputs. > Necessary to assess this flux impact on nutrient budget in lagoon. - Abstract: Several recent studies have suggested that submarine groundwater discharge (SGD) occurs in the Venice lagoon with discharge rates on the same order or larger than the surface runoff, as demonstrated previously in several other coastal zones around the world. Here, the first set of {sup 222}Rn data, along with new {sup 226}Ra data are reported, in order to investigate the occurrence and magnitude of SGD specifically in the southern basin of the lagoon. The independent connection with the Adriatic Sea (at the Chioggia inlet), in addition to the relative isolation of the water body from the main lagoon, make this area an interesting case study. There is probably only minimal fresh groundwater flux to the lagoon because the surrounding aquifer is subsiding and mainly has a lower hydraulic head than seawater. The data show that the Ra and Rn activities are in slight excess in the lagoon compared to the open sea, with values on the same order as those observed in the northern and central basins. Taking into account the water exchange rate between the lagoon and adjacent seawater provided by previous hydrodynamic numerical modelling, it is shown that this excess cannot be supported at steady state by only riverine input and by diffusive release from the sediment interstitial water. High activities observed in groundwater samples collected from 16 piezometers tapping into the shallow aquifer over the coastal lowland substantiate that the excess radioactivity in the lagoon may indeed be due to the advection of groundwater

  17. Landscape changes in a coastal system undergoing tourism development: implications for Barra de Navidad Lagoon, Jalisco, Mexico

    Directory of Open Access Journals (Sweden)

    Tara L. Holland

    2012-02-01

    Full Text Available In this study, changes in land cover and land use patterns that occurred between 1985 and 2000 in the surrounding basin of the Barra de Navidad coastal lagoon in Jalisco, Mexico are quantified and explained. Two satellite images from 1985 (Landsat TM and 2000 (Landsat ETM+ were analyzed with supervised classification and ground truthing to evaluate changes in six land use/cover categories: lagoon, agriculture, urban/tourist, tropical dry forest, mangrove and bare substratum. Changes in land use composition were evaluated using a transition matrix and changes to configuration were interpreted using landscape metrics. Results show that urban and tourist areas expanded between 1985 and 2000, mostly at the expense of forested and bare land. Mangroves showed a large relative decrease in area (-39% and experienced fragmentation. These changes appear to be related to increased sedimentation a fan progradation into Barra de Navidad lagoon. These results may serve as a model for comparison in other systems experiencing multiple stressors, especially changes related to tourism and the intensification of resource extraction.

  18. Preliminary notes on C-N ppols in sediments from the Sacca di Goro coastal lagoon (Po delta, northern Italy

    Directory of Open Access Journals (Sweden)

    Gianluca Bianchini

    2015-12-01

    Full Text Available A very hot debate is currently focused on submerged substrates that can be classified either as sediments or subaqueous soils. In this paper, the controversy is contextualized on a specific case study, i.e. the Sacca di Goro coastal lagoon facing the North Adriatic Sea. The submerged substrate has been sampled along a a E-W transect and subsequently analyzed to investigate the C-N elemental and isotopic compositions. The recorded concentration of organic carbon (OC and nitrogen is 0.26-0.50 and 0.02-0.06 wt%, respectively, and the spatial distribution of these parameters highlights a general decrease of concentration from W to E. The carbon isotopic composition of the organic matter (δ13COC indicates the incorporation within the substrate of significant amount of seaweed and seagrass. Seaweed prevails in the west (δ13COC down to -19‰ due to a nutrient-rich freshwater inflow (Po di Volano, whereas seagrass is preponderant eastward (δ13COC up to -10‰ in a sector of the lagoon fed by riverine waters characterized by lower nutrient load (Po di Goro. The existence of these biological components plausibly implies a lush benthic vegetation, properly rooted on the submerged floor. For this reason, in our view the substrate of the investigated lagoon can be regarded as a subaqueous soil.

  19. 'Blue Carbon' and Nutrient Stocks of Salt Marshes at a Temperate Coastal Lagoon (Ria de Aveiro, Portugal).

    Science.gov (United States)

    Sousa, Ana I; Santos, Danielle B; Silva, Eduardo Ferreira da; Sousa, Lisa P; Cleary, Daniel F R; Soares, Amadeu M V M; Lillebø, Ana I

    2017-01-25

    Ria de Aveiro is a mesotidal coastal lagoon with one of the largest continuous salt marshes in Europe. The objective of this work was to assess C, N and P stocks of Spartina maritima (low marsh pioneer halophyte) and Juncus maritimus (representative of mid-high marsh halophytes) combined with the contribution of Halimione portulacoides, Sarcocornia perennis, and Bolbochenous maritimus to the lagoon ≈4400 ha marsh area. A multivariate analysis (PCO), taking into account environmental variables and the annual biomass and nutrient dynamics, showed that there are no clear seasonal or spatial differences within low or mid-high marshes, but clearly separates J. maritimus and S. maritima marshes. Calculations of C, N and P stocks in the biomass of the five most representative halophytes plus the respective rhizosediment (25 cm depth), and taking into account their relative coverage, represents 252053 Mg C, 38100 Mg N and 7563 Mg P. Over 90% of the stocks are found within mid-high marshes. This work shows the importance of this lagoon's salt marshes on climate and nutrients regulation, and defines the current condition concerning the 'blue carbon' and nutrient stocks, as a basis for prospective future scenarios of salt marsh degradation or loss, namely under SLR context.

  20. I just can't put my finger on it! Approaching coastal lagoon systems with remotely sensed data

    DEFF Research Database (Denmark)

    Sander, Lasse; Kabuth, Alina Kristin

    -level fluctuations shaped the world’s coastlines as we know them today. Sediments and surface morphology tell and conserve a part of these developments on accreting coasts and in marginal marine environments, like lagoons or marshes. Most modern coastal lagoons formed in embayments after the rapid post-glacial sea......-level drop. In Denmark, high-resolution digital elevation models (DEM) are available for this purpose as are orthophotos and maps with an overall high temporal coverage. This allows a fine-tuned GIS-based interpretation of landforms, coastal dynamics and the processes that create them, even before setting...

  1. Rapid proliferation of Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae during freshwater flash floods in French Mediterranean coastal lagoons.

    Science.gov (United States)

    Esteves, Kevin; Hervio-Heath, Dominique; Mosser, Thomas; Rodier, Claire; Tournoud, Marie-George; Jumas-Bilak, Estelle; Colwell, Rita R; Monfort, Patrick

    2015-11-01

    Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae of the non-O1/non-O139 serotype are present in coastal lagoons of southern France. In these Mediterranean regions, the rivers have long low-flow periods followed by short-duration or flash floods during and after heavy intense rainstorms, particularly at the end of the summer and in autumn. These floods bring large volumes of freshwater into the lagoons, reducing their salinity. Water temperatures recorded during sampling (15 to 24°C) were favorable for the presence and multiplication of vibrios. In autumn 2011, before heavy rainfalls and flash floods, salinities ranged from 31.4 to 36.1‰ and concentrations of V. parahaemolyticus, V. vulnificus, and V. cholerae varied from 0 to 1.5 × 10(3) most probable number (MPN)/liter, 0.7 to 2.1 × 10(3) MPN/liter, and 0 to 93 MPN/liter, respectively. Following heavy rainstorms that generated severe flash flooding and heavy discharge of freshwater, salinity decreased, reaching 2.2 to 16.4‰ within 15 days, depending on the site, with a concomitant increase in Vibrio concentration to ca. 10(4) MPN/liter. The highest concentrations were reached with salinities between 10 and 20‰ for V. parahaemolyticus, 10 and 15‰ for V. vulnificus, and 5 and 12‰ for V. cholerae. Thus, an abrupt decrease in salinity caused by heavy rainfall and major flooding favored growth of human-pathogenic Vibrio spp. and their proliferation in the Languedocian lagoons. Based on these results, it is recommended that temperature and salinity monitoring be done to predict the presence of these Vibrio spp. in shellfish-harvesting areas of the lagoons. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. Reproductive dynamics of Lycengraulis grossidens (Clupeiformes: Engraulidae and Platanichthys platana (Clupeiformes: Clupeidae in a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    C. A. Lopes

    2017-11-01

    Full Text Available Abstract We evaluated the reproductive dynamics of two fish species, Lycengraulis grossidens and Platanichthys platana, in a subtropical freshwater coastal lagoon (Peri Lagoon in Brazil. Samples were collected from nine sites every two months from June 2008 to April 2012. Different fishing methods were used to capture larvae, juveniles, and adults. Limnological variables were obtained using multiparameter probe. More females than males were collected of both fish species and the chi-square test (χ2 was used to confirm that the sex ratio was female-biased. Large numbers of maturing and mature fishes were observed in almost every sampling month. The gonadosomatic index (GSI of L. grossidens was the highest in August, October, and December for females and in October for males, and no significant difference was found across years. The GSI of P. platana showed no significant difference across months for either sex; however, significant differences were recorded in year three (June 2010-April 2011 and year four (June 2011-April 2012 for females and in year three (June 2010-April 2011 for males. For both species, GSI was negatively correlated with temperature and water level. L. grossidens larvae were more abundant in October 2010, showing a positive correlation with water transparency, whereas P. platana larvae were more abundant in June 2011, showing a positive correlation with water transparency and negative correlation with temperature and precipitation. Both species were represented by different stages, including larvae, which confirm that these species reproduce in Peri Lagoon. Reproduction was more pronounced in autumn and winter; however, reproductive activity was evident throughout the sampling period. In conclusion, our results show that abiotic factors strongly influence the temporal pattern of reproductive activity and larval assemblages of both L. grossidens and P. platana in Peri Lagoon, Brazil.

  3. Species-area relationships as a tool for the conservation of benthic invertebrates in Italian coastal lagoons

    Science.gov (United States)

    Guilhaumon, François; Basset, Alberto; Barbone, Enrico; Mouillot, David

    2012-12-01

    Over the recent decades, the preservation of coastal and estuarine waters has been recognised as a priority at national and international levels. At the European scale, the Water Framework Directive (WFD) was established with the aim to achieve a good ecological status of all significant water bodies by the year 2015. Among the descriptors used to define the ecological status of water bodies, taxonomic diversity (usually species richness) is a widespread metric employed across taxa and habitats. However, species richness is known to increase with area at a decelerating rate, producing the species-area relationship (SAR). Thus, removing the effect of area (even in case of low magnitude), is mandatory before comparing species richness between sites. Here we tested recently developed multi-model SARs as a standardisation tool for comparing benthic species richness (annelids, arthropods, molluscs and total species richness) in 18 Italian coastal lagoons with a surface area ranging from 0.19 to 552 km2, i.e. three orders of magnitude. However, the sampling effort was often incompletely described and certainly heterogeneous among the studies retrieved from the database. Therefore, we used the number of studies as a proxy for the sampling effort in each lagoon and estimated species richness from observed values using non-parametric occurrence-based estimators. We further corrected for bias that might be induced by sampling efforts being unrepresentative for the surface area of different lagoons. After applying these corrections, we estimated that c. 25-30% of species richness could be explained by surface area. We investigated the spatial congruence of species richness patterns across taxa and showed that molluscs could serve as a potential surrogate for total macro-invertebrate species richness. We further found that the intensity of conservation focus and the gradient of ecological status are decoupled in Italian coastal lagoons. More generally, our study pave the way

  4. Competition Between Barrier Island Migration and Marsh-Upland Migration Could Determine the Fate of Coastal Lagoons Under Sea Level Rise.

    Science.gov (United States)

    Duran Vinent, O.; Kirwan, M. L.

    2016-12-01

    Although marshes can modulate their vertical growth to adjust to sea level rise, wave-induced marsh edge erosion seems to be unstoppable, eating away large chunks of marshes around coastal lagoons in low-sediment environments. Because lagoon size is ultimately constrained by barrier islands, a positive feedback ensues by which barrier migration decreases lagoon size and wind fetch, which in turn reduces marsh edge erosion. Under sea level rise, back-barrier marshes and bay sediments are eventually exposed at the seashore where they are eroded away by waves, thereby increasing barrier island migration rate and further mitigating fetch-driven marsh erosion. We study this feedback using a simple model that couples barrier, lagoon, marsh, and upland components of the coastal landscape. We find that the final state of the ecosystem is controlled by the relation between barrier migration rate, marsh edge erosion rate and marsh upland propagation rate. Our results suggest there are two stable, extreme long-term scenarios, which are a function of the rate of sea level rise and sediment availability: (i) a growing lagoon devoid of marshes, for slowly migrating barrier islands and limited upland marsh transgression; and (ii) a marsh filled lagoon, for fast migrating barrier islands, and unconstrained upland marsh transgression.

  5. Impacts of maintenance channel dredging in a northern Adriatic coastal lagoon. II: Effects on macrobenthic assemblages in channels and ponds

    Science.gov (United States)

    Ponti, Massimo; Pasteris, Andrea; Guerra, Roberta; Abbiati, Marco

    2009-10-01

    Coastal lagoons are ephemeral habitats whose conservation requires human intervention, such as maintenance dredging of inner channels. Dredging can reduce the abundance of benthic species due to the removal of individuals with the sediment, modify sediment properties, and resuspend fine sediment, nutrients and pollutants, which can lead to eutrophication, hypoxic events and increasing toxicity. Both direct effects in the dredged channel and possible indirect effects in surrounding shallow areas could be expected. This study assesses the effects of the channel maintenance dredging, performed between October 2004 and August 2005, on the invertebrate assemblages both in channels and adjacent ponds in the northern Adriatic coastal lagoon of Pialassa Baiona. The lagoon is affected by eutrophication, chemical and thermal pollution from wastewater treatment and power plants. Three impacted sites were located in the dredged channel and three in the adjacent interconnected shallow water ponds, while three non-impacted sites were located in a channel and in a pond far from the dredged area. Replicate samples were collected from each site one time before and one time after the dredging operations. Despite the extent of the intervention, effects of the dredging on macrobenthic assemblages were detected only within the dredged channel, while in the surrounding ponds no clear and unequivocal effects were found. In particular the dredging could have promoted the increase of the abundance of the polychaete Streblospio shrubsolii in the southern and central parts of the dredged channel and the increase in abundance of the amphipod Corophium insidiosum in the northern side, compared to the controls. Instead, species diversity was reduced in the central and northern parts of the dredged channel. These effects on the macrobenthic invertebrate assemblages could be related to the observed changes of sediment characteristics, contamination and toxicity. Overall, direct effects on benthic

  6. New Caledonia surface lagoon chlorophyll modeling as coastal reef area health indicator

    Science.gov (United States)

    Fuchs, R.; Pinazo, C.; Douillet, P.; Dupouy, C.; Faure, V.; Mangin, A.

    2010-10-01

    The major part of the New Caledonia (NC) lagoon was classified as UNESCO Natural Site of Humanity Patrimony. Indeed, 22 175 km2 of tropical coral lagoon area exhibit high biodiversity. The NC lagoon is semi enclosed and connected to the Coral Sea through a barrier reef segmented by narrow passes. The environment is oligotrophic, due to important flush during trade winds events, and bathymetry is highly variable. In order to predict eutrophication events, we used an extension of a 3D coupled physical-biogeochemical model recently developed on NC south western lagoon. The model is based on the Nitrogen and Carbon cycles, relating the variable stoechiometry of the elements in each biological compartment. The ecological model was developed to include an explicit description of the microbial loop. The resulting coupled model, forced by tide, wind, light, temperature and freshwater inputs, was used to calculate phytoplankton biomass, bacterial production, dissolved organic matter concentrations and nutrient recycling. Here we present results issued from the 3D coupled model ECO3M_LAGOON (biogeochemical, LOPB-IRD) and MARS3D (regional physical model, IFREMER-IRD) describing spatial and temporal interactions between water motion and biology, on larger domain including reef barrier and water exchanges through ocean-lagoon interface. To validate physical processes in the lagoon we used in situ data collected during field cruise (ValHyBio 2008, La Niña episode). Surface chlorophyll concentrations are compared with water color data from ValHyBio cruise and satellite data (MODIS/MERIS) corrected from bathymetry effects.

  7. Coastal lagoon systems as indicator of Holocene sea-level development in a periglacial soft-sediment setting: Samsø, Denmark

    DEFF Research Database (Denmark)

    Sander, Lasse; Fruergaard, Mikkel; Johannessen, Peter N.

    2014-01-01

    . Stratigraphy, grain-size distribution, fossil and organic matter content of cores retrieved from the lagoons were analyzed and compared. Age control was established using radiocarbon and optically stimulated luminescence dating. Our data produced a surprisingly consistent pattern for the sedimentary...... successions found in the lagoons. The period of initial transgression can be identified as the onset of deposition of fine-grained, organic-rich sediments. However, radiocarbon dates evidence a punctuation of these deposits further upcore. Grain-size analysis suggests that the reworking and abrasion....... The common occurrence of similar environments distributed along gradients of isostatic uplift/subsidence (approximately +0,5 to -0,5 mm/yr) in the south-western Baltic, makes coastal lagoon systems a valuable archive for the reconstruction of Holocene sea-level and coastal evolution....

  8. Numerical and experimental investigations of submarine groundwater discharge to a coastal lagoon

    DEFF Research Database (Denmark)

    Haider, Kinza

    of the groundwater discharge occurred near the shoreline of the lagoon, but also off-shore discharge from deep confined aquifers system occurred at places where confining clay layers are eroded by buried valleys. The simulated fresh groundwater discharge was a non-negligible component, 59 % of recharge on the lagoon......The main goal of this study is to understand and estimate the amount of submarine groundwater discharge into Ringkøbing Fjord from shallow and deep aquifer systems at the Eastern shoreline from Ringkøbing catchment in Western Denmark. In order to accomplish this objective, the study was initiated...... using an existing large-scale airborne geophysical survey and hydrogeological data from the boreholes in the study area. This data helped in locating zones of groundwater discharge as well estimating complex salinity distribution under the sediment bed along with information about geology under lagoon...

  9. Combined environmental stress from shrimp farm and dredging releases in a subtropical coastal lagoon (SE Gulf of California).

    Science.gov (United States)

    Cardoso-Mohedano, J G; Páez-Osuna, F; Amezcua-Martínez, F; Ruiz-Fernández, A C; Ramírez-Reséndiz, G; Sanchez-Cabeza, J A

    2016-03-15

    Nutrient pollution causes environmental damages on aquatic ecosystems worldwide. Eutrophication produces impacts in coastal ecosystems, affecting biota and ecosystem services. The Urias coastal lagoon (SE Gulf of California) is a sub-tropical estuary under several environmental pressures such as nutrient inputs from shrimp farm effluents and dredging related to port operations, which can release substances accumulated in sediments. We assessed the water quality impacts caused by these activities and results showed that i) nitrogen was the limiting nutrient, ii) shrimp farm effluents increased particulate organic matter and chlorophyll a in the receiving stations, and iii) dredging activities increased nitrite and reduced dissolved oxygen concentrations. The co-occurrence of the shrimp farm releases and dredging activities was likely the cause of a negative synergistic effect on water quality which mainly decreases dissolved oxygen and increases nitrite concentrations. Coastal zone management should avoid the co-occurrence of these, and likely others, stressors in coastal ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Sulfide-induced release of phosphate from sediments of coastal lagoons and the possible relation to the disappearance of Ruppia sp

    NARCIS (Netherlands)

    Heijs, S.K.; Azzoni, R.; Giordani, G.; Jonkers, H.M.; Nizzoli, D.; Viaroli, P.; van Gemerden, H.

    2000-01-01

    The production and consumption of sulfide and its influence on phosphorous cycling were studied in a hypertrophic coastal lagoon (Valle Smarlacca, Italy). Oxygen measurements revealed that the water phase was supersaturated except for the layer directly overlying the sediment. This layer was devoid

  11. Sulfide-induced release of phosphate from sediments of coastal lagoons and the possible relation to the disappearance of Ruppia sp.

    NARCIS (Netherlands)

    Heijs, SK; Azzoni, R; Giordani, G; Jonkers, HM; Nizzoli, D; Viaroli, P; van Gemerden, H

    2000-01-01

    The production and consumption of sulfide and its influence on phosphorous cycling were studied in a hypertrophic coastal lagoon (Valle Smarlacca, Italy). Oxygen measurements revealed that the water phase was supersaturated except for the layer directly overlying the sediment. This layer was devoid

  12. Hepatic retinoid levels in seven fish species (teleosts) from a tropical coastal lagoon receiving effluents from iron-ore mining and processing

    NARCIS (Netherlands)

    Alves Pereira Wilken, A.; van Hattum, A.G.M.; Brouwer, A.

    2012-01-01

    The present study was undertaken to investigate the possible effects of Fe and trace element exposure on hepatic levels of retinoids in seven fish species. Concentrations of retinoids were measured in fish collected from a coastal lagoon in Brazil that receives effluents from an iron-ore mining and

  13. Residual currents and fluxes through the mouth of Vassova coastal lagoon

    Directory of Open Access Journals (Sweden)

    G. SYLAIOS

    2003-12-01

    Full Text Available An intensive sampling program of physical and chemical parameters at the mouth of Vassova lagoon (Northern Greece during 4 separate tidal cycles is described. The study aims at understanding the tidal circulation and estimating the instantaneous and residual fluxes of water, salt and nutrients through the entrance canal of this micro-tidal lagoon. Results showed that tidal flood exceeded in duration tidal ebb, under spring and neap tidal conditions. Ebb tidal currents were recorded higher than flood currents, especially under neap tidal conditions. Unsteady flow characterized the temporal variation of longitudinal and lateral velocity, inducing a rightward deflection on flood or ebb flow. The intra-tidal variability of dissolved inorganic nitrogen showed seasonal dependence, with higher values during September, October and early March, and lower during the late March period. Residual current and flux analysis into a Eulerian and a mass transport Stokes drift mechanism illustrated that advective water and dissolved parameters (i.e., salt and nitrates, phosphates and chlorophyll-· fluxes were an order of magnitude higher than tidal pumping effects. Water and dissolved constituents moved into the lagoon under neap tidal conditions and out of the lagoon during spring tidal conditions. Calculated flushing times ranged from 5 to 14 days, with neap tidal conditions and nearly zero freshwater discharge producing the longer flushing time. Lower water flushing effects were generated under spring tides and increased precipitation.

  14. Spatiotemporal distribution and composition of phytoplankton assemblages in a coastal tropical lagoon: Chilika, India.

    Science.gov (United States)

    Srichandan, Suchismita; Kim, Ji Yoon; Bhadury, Punyasloke; Barik, Saroja K; Muduli, Pradipta R; Samal, Rabindro N; Pattnaik, Ajit K; Rastogi, Gurdeep

    2015-02-01

    The Asia's largest lagoon, Chilika, is a shallow water estuary and a designated "Ramsar" site located in the east coast of India. The spatiotemporal diversity of phytoplankton based on the monthly sampling between July 2011 and June 2012 was investigated in relation to physicochemical variables of the surface water column from 13 stations. The salinity was minimum (average 9) during the monsoon which was primarily due to riverine discharge. As the season progressed towards post-monsoon, average salinity of the whole lagoon reached to 10 which further increased to 20 during pre-monsoon season. A total of 259 species of phytoplankton, mostly dominated by the Bacillariophyta (138 species) followed by Dinophyta (38 species), Chlorophyta (32 species), Cyanophyta (29 species), Euglenophyta (18 species), and Chrysophyta (4 species), were recorded in this study. Different ecological sectors of the lagoon (except the northern sector) were dominated by diatoms, while the northern sector due to its freshwater regime supported large population of euglenoids. Based on the multivariate ordination analysis, salinity regime and light availability played important role in determining the distribution, diversity, and composition of phytoplankton communities. Overall, this study documented a very high diversity of phytoplankton and highlighted the importance of taking extensive sampling in getting a clearer understanding of phytoplankton community structure in less-studied environments such as Chilika lagoon.

  15. A review of the influence of biogeography, riverine linkages, and marine connectivity on fish assemblages in evolving lagoons and lakes of coastal southern Africa.

    Science.gov (United States)

    Whitfield, Alan K; Weerts, Steven P; Weyl, Olaf L F

    2017-09-01

    The Holocene evolution of eight South African coastal lakes and lagoons is examined and related to changes in fish composition over that period. Historical and current connectivity with riverine and marine environments are the primary determinants of present-day fish assemblages in these systems. A small and remarkably consistent group of relict estuarine species have persisted in these coastal lakes and lagoons. The loss or reduction of connectivity with the sea has impacted on the diversity of marine fishes in all eight study systems, with no marine fishes occurring in those water bodies where connectivity has been completely broken (e.g. Sibaya, Groenvlei). In systems that have retained tenuous linkages with the sea (e.g., Verlorenvlei, Wilderness lakes), elements of the marine fish assemblage have persisted, especially the presence of facultative catadromous species. Freshwater fish diversity in coastal lakes and lagoons is a function of historical and present biogeography and salinity. From a freshwater biogeography perspective, the inflowing rivers of the four temperate systems reviewed here contain three or fewer native freshwater fishes, while the subtropical lakes that are fed by river systems contain up to 40 freshwater fish species. Thus, the significantly higher fish species diversity in subtropical versus temperate coastal lakes and lagoons comes as no surprise. Fish species diversity has been increased further in some systems (e.g., Groenvlei) by alien fish introductions. However, the impacts of fish introductions and translocations have not been studied in the coastal lakes and lagoons of South Africa. In these closed systems, it is probable that predation impacts on small estuarine fishes are significant. The recent alien fish introductions is an example of the growing threats to these systems during the Anthropocene, a period when human activities have had significant negative impacts and show potential to match the changes recorded during the

  16. Parasite assemblages of estuarine-dependent marine fishes from Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina).

    Science.gov (United States)

    Alarcos, Ana Julia; Etchegoin, Jorge Alejandro

    2010-10-01

    The estuarine-dependent marine fish includes marine species that inhabit, at some stage of their life cycle, the Mar Chiquita coastal lagoon, Buenos Aires Province, Argentina. In the present study, we examined for parasites a total of 209 fishes belonging to following the estuarine-dependent marine species: Brevoortia aurea, Odontesthes argentinensis, Mugil platanus, Paralichthys orbignyanus, Micropogonias furnieri, and Pogonias cromis. The parasite fauna in the six host species comprised 43 parasite species, the majority of which represented new locality and new host records. A high percentage of fish was parasitized with at least one parasite species. The greatest values of prevalence were registered for M. furnieri, B. aurea, and P. cromis, at the component community level, followed by P. orbignyanus, O. argentinensis, and M. platanus. On the other hand, B. aurea, O. argentinensis, M. furnieri, and P. cromis showed similar percentages of both larval and adult stages of parasites. In the case of M. platanus, adult stages dominated the total number of parasites, whereas P. orbignyanus harbored mainly larval stages. Out of the six fish species herein studied, M. platanus seems to generally act only as definitive host in the local parasite's life cycle. From a parasitological point of view, the expression "estuarine-dependent marine fishes" remains valid, although the contribution of the fish species in the lagoon to the maintenance of parasite populations is relatively minor.

  17. Natural Recovery and Planned Intervention in Coastal Wetlands: Venice Lagoon (Northern Adriatic Sea, Italy as a Case Study

    Directory of Open Access Journals (Sweden)

    Chiara Facca

    2014-01-01

    Full Text Available The goals of conservation and sustainable use of environmental ecosystems have increased the need for detailed knowledge of ecological evolution and responses to both anthropogenic pressures and recovery measures. The present study shows the effects of natural processes and planned intervention in terms of reducing nutrient inputs in a highly exploited coastal lagoon, describing its evolution over a 16-year period from the late 1980s (when eutrophication was at its peak until 2003. Changes in nutrient and carbon concentrations in the top layer of sediments were investigated in parallel with macroalgal and seagrass biomass in the most anthropized basin of Venice Lagoon in four surveys conducted in accordance with the same protocols in 1987, 1993, 1998, and 2003. A pronounced reduction in trophic state (mainly total nitrogen, organic phosphorus, and organic carbon concentrations and macroalgal biomass was recorded, together with the progressive expansion of seagrass meadows. General considerations are also made on the effects of Manila clam farming and the shift from illegal to managed clam farming.

  18. Evaluation of sediment contamination by monoaromatic hydrocarbons in the coastal lagoons of Gulf of Saros, NE Aegean Sea.

    Science.gov (United States)

    Ünlü, Selma; Alpar, Bedri

    2017-05-15

    The concentrations and distribution of monoaromatic hydrocarbons (benzene, toluene, ethyl benzene and the sum of m-, p- and o-, xylenes) were determined in the sediments of coastal lagoons of the Gulf of Saros, using a static headspace GC-MS. The total concentrations of BTEX compounds ranged from 368.5 to below detection limit 0.6μgkg-1 dw, with a mean value of 61.5μgkg-1 dw. The light aromatic fraction of m-, p-xylene was the most abundant compound (57.1% in average), and followed by toluene (38.1%)>ethylbenzene (4.1%)>o-xylene (2.5%)>benzene (1.1%). The factor analysis indicated that the levels and distribution of BTEX compounds depend on the type of contaminant source (mobile/point), absorbance of compounds in sediment, and mobility of benzene compound and degradation processes. Point sources are mainly related to agricultural facilities and port activities while the dispersion of compounds are related with their solubility, volatility and effect of sea/saline waters on lagoons. Copyright © 2017. Published by Elsevier Ltd.

  19. Coastal Evolution in a Mediterranean Microtidal Zone: Mid to Late Holocene Natural Dynamics and Human Management of the Castello Lagoon, NE Spain.

    Directory of Open Access Journals (Sweden)

    Ana Ejarque

    Full Text Available We present a palaeoenvironmental study of the Castelló lagoon (NE Spain, an important archive for understanding long-term interactions between dynamic littoral ecosystems and human management. Combining geochemistry, mineralogy, ostracods, diatoms, pollen, non-pollen palynomorphs, charcoal and archaeo-historical datasets we reconstruct: 1 the transition of the lagoon from a marine to a marginal environment between ~3150 cal BC to the 17th century AD; 2 fluctuations in salinity; and 3 natural and anthropogenic forces contributing to these changes. From the Late Neolithic to the Medieval period the lagoon ecosystem was driven by changing marine influence and the land was mainly exploited for grazing, with little evidence for impact on the natural woodland. Land-use exploitation adapted to natural coastal dynamics, with maximum marine flooding hampering agropastoral activities between ~1550 and ~150 cal BC. In contrast, societies actively controlled the lagoon dynamics and become a major agent of landscape transformation after the Medieval period. The removal of littoral woodlands after the 8th century was followed by the expansion of agrarian and industrial activities. Regional mining and smelting activities polluted the lagoon with heavy metals from the ~11th century onwards. The expansion of the milling industry and of agricultural lands led to the channelization of the river Muga into the lagoon after ~1250 cal AD. This caused its transformation into a freshwater lake, increased nutrient load, and the infilling and drainage of a great part of the lagoon. By tracking the shift towards an anthropogenically-controlled system around ~750 yr ago, this study points out Mediterranean lagoons as ancient and heavily-modified systems, with anthropogenic impacts and controls covering multi-centennial and even millennial timescales. Finally, we contributed to the future construction of reliable seashell-based chronologies in NE Spain by calibrating the

  20. Patterns of trace element bioaccumulation in jellyfish Rhizostoma pulmo (Cnidaria, Scyphozoa) in a Mediterranean coastal lagoon from SE Spain.

    Science.gov (United States)

    Muñoz-Vera, Ana; Peñas Castejón, Jose Matías; García, Gregorio

    2016-09-15

    The effects of an abandoned mining area, exploited for centuries in the mining district of Cartagena-La Union, result in a continuous supply of heavy metals into the Mar Menor coastal lagoon after rain episodes. As a consequence, concentration of trace elements in water column and sediments of this ecosystem is usually higher than in other areas. For monitoring ecosystem health, this study assessed the ability of Rhizostoma pulmo to bioaccumulate trace elements. A total of 57 individuals were sampled at eight different sampling stations during the summer of 2012. Although the concentrations of different analyzed elements (Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Sn, and Pb) were moderate, bioconcentration levels in relation to seawater metal concentration were extremely high. In any case, the use or disposal of these organisms should consider their metal content, because of their potential environmental and health implications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Total mercury in muscles and liver of Mugil spp. from three coastal lagoons of NW Mexico: concentrations and risk assessment.

    Science.gov (United States)

    Delgado-Alvarez, C G; Frías-Espericueta, M G; Ruelas-Inzunza, J; Becerra-Álvarez, M J; Osuna-Martínez, C C; Aguilar-Juárez, M; Osuna-López, J I; Escobar-Sánchez, O; Voltolina, D

    2017-07-01

    Total mercury (Hg) concentrations were determined by atomic absorption spectrophotometry in muscles and liver of composite samples of Mugil cephalus and M. curema collected during November 2013 and in January, April, and July 2014 from the coastal lagoons Altata-Ensenada del Pabellón (AEP), Ceuta (CEU), and Teacapán-Agua Brava (TAG) of Sinaloa State. The mean Hg contents and information on local consumption were used to assess the possible risk caused by fish ingestion. Mean total mercury levels in the muscles ranged from 0.11 to 0.39 μg/g, while the range for liver was 0.12-3.91 μg/g. The mean Hg content of the liver was significantly (p mercury calculated for the younger age classes of one fishing community were >1, indicating a possible risk for some fishing communities of the Mexican Pacific coast.

  2. Persistent organic pollutants (POPs) in populations of the clam Chione californiensis in coastal lagoons of the Gulf of California.

    Science.gov (United States)

    Vargas-González, Héctor H; Méndez-Rodríguez, Lía C; García-Hernández, Jaqueline; Mendoza-Salgado, Renato A; Zenteno-Savín, Tania; Arreola-Lizárraga, José A

    2016-07-02

    This study examines the potential public health risk due to the massive use of organochlorine pesticides (OCs) in agriculture in the Gulf of California. Specimens of the clam Chione californiensis were collected from three coastal lagoons (Yavaros, Altata and Reforma). Sites were classified as polluted/nonpolluted based on the presence/absence of OCs as an indicator of the persistence of these pollutants; in polluted sites, the time elapsed since pesticide application (past or recent) was estimated. Screening values (SV) for protecting human health as per the U.S. Environmental Protection Agency (EPA) were used for risk assessment. OCs detected were ranked according to frequency of occurrence as follows: γ-chlordane (75%) > endrin (54%) > aldrin (48%) > heptachlor, and dichlorodiphenyl-trichloroethane (DDE) (37%) > β-heptachlor epoxide (30%) > lindane (α-BHC, δ-BHC) and endosulphan I (≤ 6%). Specifically, OCs detected at the highest concentration were heptachlor in Yavaros (0.0168 µgg(-1)) and Altata (0.0046 µgg(-1)), and aldrin in Reforma (0.0019 µgg(-1)). β-Heptachlor epoxide in Altata and Reforma was the only OC with a concentration exceeding the EPA Screening Value. From our results and based on the monthly consumption limit set forth by EPA, the maximum safe consumption of clams to avoid a carcinogenic risk derived from β-heptachlor epoxide in the fishing villages of Yavaros and Altata is 4 servings per month (1 serving = 0.227 kg) by a 70-kg person. These findings suggest that concentrations of OCs and their isomers in C. californiensis populations reflect environmental persistence as well as recent inputs of OCs into coastal lagoons in the Gulf of California.

  3. Effects of artificial disturbance on quantity and biochemical composition of organic matter in sediments of a coastal lagoon

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    Lenzi M.

    2011-10-01

    Full Text Available The eutrophication of the coastal lagoon of Burano (Tuscany, Italy produces periodic toxic-anoxic events. The possibility of mitigating eutrophication of a lagoon by resuspension of sediment was tested in a three-year field experiment conducted in 2008–2009. An unreplicated before-after control-impact (BACI study design was used to ascertain variations in the quantity and biochemical composition of organic matter in sediment artificially disturbed by a specially equipped boat. In October 2008, before beginning disturbance, January 2009, half way through the disturbance period, and May 2009, at the end of disturbance, sediment was sampled in a disturbed area and an undisturbed control area to determine chlorophyll-a (Chl-a, phaeopigments (PHAE, proteins (PRT, carbohydrates (CHO, lipids (LIP, labile organic matter (LOM, refractory organic matter (ROM, total organic carbon (TOC and total nitrogen (TN. The disturbed area, measuring 44 ha, was divided into nine subareas, eight of which were subjected to four different frequencies of disturbance (from 2 to 5 in the period October 2008 – April 2009. Sediment was sampled in each sub-area in the three months mentioned above to determine labile and total organic matter. The results were processed by univariate and multivariate analysis using Primer 6.0, Permanova  +  and Prism 5.0 software. The findings were as follows: (1 a large proportion of the biopolymeric carbon consisted of labile matter throughout the lagoon; (2 higher abatement of labile organic matter was recorded in the disturbed area; (3 a lower protein:carbohydrate ratio was found in the disturbed than in the undisturbed area; (4 the C:N ratio of sediment was much lower in the undisturbed area than in the disturbed area at the end of the study period; (5 sediment and macroalgal C:N ratios did not significantly change in response to disturbance; (6 initial accumulation of organic matter from phytoplankton was greater in the disturbed

  4. Assessment of the trophic status of four coastal lagoons and one estuarine delta, eastern Brazil.

    Science.gov (United States)

    Cotovicz Junior, Luiz Carlos; Brandini, Nilva; Knoppers, Bastiaan Adriaan; Mizerkowski, Byanka Damian; Sterza, José Mauro; Ovalle, Alvaro Ramon Coelho; Medeiros, Paulo Ricardo Petter

    2013-04-01

    Anthropogenic eutrophication of aquatic ecosystems continues to be one of the major environmental issues worldwide and also of Brazil. Over the last five decades, several approaches have been proposed to discern the trophic state and the natural and cultural processes involved in eutrophication, including the multi-parameter Assessment of Estuarine Trophic Status (ASSETS) index model. This study applies ASSETS to four Brazilian lagoons (Mundaú, Manguaba, Guarapina, and Piratininga) and one estuarine delta (Paraíba do Sul River), set along the eastern Brazilian coast. The model combines three indices based on the pressure-state-response (PSR) approach to rank the trophic status and forecast the potential eutrophication of a system, to which a final ASSETS grade is established. The lagoons were classified as being eutrophic and highly susceptible to eutrophication, due primarily to their longer residence times but also their high nutrient input index. ASSETS classified the estuary of the Paraíba do Sul river with a low to moderate trophic state (e.g., largely mesotrophic) and low susceptibility to eutrophication. Its nutrient input index was high, but the natural high dilution and flushing potential driven by river flow mitigated the susceptibility to eutrophication. Eutrophication forecasting provided more favorable trends for the Mundaú and Manguaba lagoons and the Paraíba do Sul estuary, in view of the larger investments in wastewater treatment and remediation plans. The final ASSETS ranking system established the lagoons of Mundaú as "moderate," Manguaba as "bad," Guarapina as "poor," and Piratininga as "bad," whereas the Paraíba do Sul River Estuary was "good."

  5. Effect of algal blooms on retention of N, Si and P in Europe's largest coastal lagoon

    Science.gov (United States)

    Vybernaite-Lubiene, I.; Zilius, M.; Giordani, G.; Petkuviene, J.; Vaiciute, D.; Bukaveckas, P. A.; Bartoli, M.

    2017-07-01

    Nutrient fluxes from land to sea are regulated by climatic factors governing hydrologic loading rates (e.g., storm events, snowmelt) and by internal processes within estuaries that affect nutrient transformation and retention. We compared monthly input and output fluxes of N, Si, and P at the entrance and exit of the hypereutrophic Curonian Lagoon to better understand how seasonal changes in the stoichiometry of nutrient inputs and the occurrence of algal blooms affected nutrient retention within the lagoon. Nutrient ratios were indicative of increasing Si and N limitation during the growing season, and these were associated with a shift from a diatom-based to a cyanobacteria dominated phytoplankton community. The estuary was a net sink for dissolved nutrients, but we observed large interannual difference in the overall retention of N and P. The occurrence of a large cyanobacteria bloom in 2012 was associated with increased export of particulate matter to the Baltic Sea resulting in a net surplus of P export. Bloom conditions mobilized P from sediments and resulted in a shift from net retention to net export for the lagoon. The findings of our study illustrate how changes in nutrient loading ratios influence phytoplankton community composition, which in turn alters the source-sink status of the estuary.

  6. Structure and diversity of fishes in a freshwater and coastal subtropical lagoon.

    Science.gov (United States)

    Ferreira, N C; Guereschi, R M; Machado, C; Lopes, C A; Nuñer, A P O

    2017-04-01

    This study examined the fish communities of Peri Lagoon in southern Brazil to aid in the development of an effective management plan because the area is under threat from human activities. Sampling of fish fauna, ichthyoplankton and limnological data were compared between sites, differing by habitat type and characteristics such as depth, substratum composition and vegetation type. Results were significantly related to site, with the highest diversity and abundance recorded at shallow vegetated sites. A total of 14 fish species were recorded throughout the lagoon, with the most abundant being Hyphessobrycon luetkenii. Of the 14 species, half were sampled at their larval stage, suggesting a healthy and protected system. Significantly more larvae and eggs were collected during colder months (autumn to winter) and at sites closer to stream flow, possibly owing to increased food sources and habitat protection. This study highlights the importance of Peri Lagoon as a nursery ground for a wide range of fish species, providing essential information for incorporation into the future protection of fish stocks throughout Brazil. © 2016 The Fisheries Society of the British Isles.

  7. Introducing a Regulatory Policy Framework of Bait Fishing in European Coastal Lagoons: The Case of Ria de Aveiro in Portugal

    Directory of Open Access Journals (Sweden)

    Stefanos Xenarios

    2018-01-01

    Full Text Available The harvesting of bait through digging in coastal mudflats is practiced for recreational and commercial purposes in European coastal systems including the Ria de Aveiro coastal lagoon on the northwest Atlantic coast of Portugal. The scale of harvesting in the Ria de Aveiro has recently increased due to the current economic climate in Portugal, with targeting of the polychaete, Diopatra neapolitana species or “casulo” as it is widely known in the Aveiro region. The national authorities have attempted to control casulo digging by issuing a regulation (Ordinance in 2014 on the maximum daily catch limit to be caught by each individual. The daily catch limit is intended to represent the Maximum Sustainable Yield (MSY for casulo beyond which overfishing will occur. The monitoring of the regulatory measures is expected to be conducted through on-site inspections in the digging areas. However, weak law enforcement was noticed, while there is also controversy over the daily catch limit (quota stipulated by the Ordinance. To this end, the current study attempted to assess digging activities through remote monitoring and random inspections for a better policy enforcement of the national regulation. In addition, different harvesting scenarios were employed through a simplified bioeconomic model to attribute the current and future harvesting trends of bait digging in Aveiro coastal lagoon. The study findings indicate that remote monitoring coupled with some onsite interviews could be a more effective approach for the implementation of the current bait digging policy. Further, the results point to a distinctive discrepancy between the daily catch amount (MSY introduced by the national legislation and the study findings which should be further scrutinized. The diggers seem to have reached the sustainable harvest identified by the present research. The current economic hardship in Portugal and the low profitability in similar employment sectors will

  8. Salgado Lagoon and the anthropic action in its Protected Coastal Zone, Northern Region of the Brazilian State of Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Caroline Cabral Tudesco

    2012-04-01

    Full Text Available This study is about Salgado Lagoon, the anthropic action in its Protected Coastal Zone over the years and the possible impacts arising from urbanization occurred in the Açu Superport and in future enterprises in its region, by making a comparative analysis with the case of the Vigário Lagoon in the city of Campos dos Goytacazes, which suffers problems caused by an uncontrolled growth and lack of planning. The occurrence of recent stromatolites, only found in South America, included the Salgado Lagoon as a geo-paleontological site in UNESCO World Heritage list, which makes the problem even more relevant. Consequently, urgent and drastic measures must be taken to protect this geological-paleontological site.

  9. Sedimentary record of recent climate impacts on an insular coastal lagoon in the Gulf of California

    Science.gov (United States)

    Cuellar-Martinez, Tomasa; Ruiz-Fernández, Ana Carolina; Sanchez-Cabeza, Joan-Albert; Alonso-Rodríguez, Rosalba

    2017-03-01

    Sedimentary records are useful to evaluate environmental changes, either from natural or anthropogenic causes, such as global and climate change. The recent changes in accumulation rates and geochemical characteristics (grain size distribution, elemental composition, organic carbon and carbonate concentrations) recorded in a sediment core from San Jose Island Lagoon (SJIL, Gulf of California) were evaluated to determine its relationship with anthropogenic impacts and climatic variability. The 210Pb-derived chronology was corroborated with 239+240Pu and 137Cs stratigraphic markers. The mass accumulation rate increased up to ∼3 times during the past ∼100 years (0.16 ± 0.03 to 0.51 ± 0.06 g cm-2 yr-1). The contents of terrigenous and marine (salinity) indicator elements, as well as fine-grained sediments, also increased considerably, although no anthropization evidences were observed; indeed, the enrichment factor of trace elements indicated that the ecosystem is still a pristine environment. By using multivariate statistical techniques, we inferred that the larger input of fine-grained terrigenous sediments could be related to the enhancement of soil erosion from the catchment, under the influence of higher rainfall rates, especially during the last 20 years. In addition, the higher concentrations of salinity indicator elements most likely resulted from higher evaporation rates in the lagoon, caused by higher minimum atmospheric temperatures. We concluded that recent climate variability has become the main driver for sedimentary geochemical changes in San Jose Island Lagoon. These observations confirmed the usefulness of 210Pb-dated geochemical sediment records to study the impacts of recent climate variability where long-term environmental data is scarce or non-existent.

  10. Distribution of picophytoplankton communities from brackish to hypersaline waters in a South Australian coastal lagoon.

    Science.gov (United States)

    Schapira, Mathilde; Buscot, Marie-Jeanne; Pollet, Thomas; Leterme, Sophie C; Seuront, Laurent

    2010-02-24

    Picophytoplankton (i.e. cyanobacteria and pico-eukaryotes) are abundant and ecologically critical components of the autotrophic communities in the pelagic realm. These micro-organisms colonized a variety of extreme environments including high salinity waters. However, the distribution of these organisms along strong salinity gradient has barely been investigated. The abundance and community structure of cyanobacteria and pico-eukaryotes were investigated along a natural continuous salinity gradient (1.8% to 15.5%) using flow cytometry. Highest picophytoplankton abundances were recorded under salinity conditions ranging between 8.0% and 11.0% (1.3 x 106 to 1.4 x 106 cells ml-1). Two populations of picocyanobacteria (likely Synechococcus and Prochlorococcus) and 5 distinct populations of pico-eukaryotes were identified along the salinity gradient. The picophytoplankton cytometric-richness decreased with salinity and the most cytometrically diversified community (4 to 7 populations) was observed in the brackish-marine part of the lagoon (i.e. salinity below 3.5%). One population of pico-eukaryote dominated the community throughout the salinity gradient and was responsible for the bloom observed between 8.0% and 11.0%. Finally only this halotolerant population and Prochlorococcus-like picocyanobacteria were identified in hypersaline waters (i.e. above 14.0%). Salinity was identified as the main factor structuring the distribution of picophytoplankton along the lagoon. However, nutritive conditions, viral lysis and microzooplankton grazing are also suggested as potentially important players in controlling the abundance and diversity of picophytoplankton along the lagoon. The complex patterns described here represent the first observation of picophytoplankton dynamics along a continuous gradient where salinity increases from 1.8% to 15.5%. This result provides new insight into the distribution of pico-autotrophic organisms along strong salinity gradients and allows for a

  11. Experimental evidence of the effect of nutrient enrichment on the zooplankton in a Brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    B. KOZLOWSKY-SUZUKI

    Full Text Available Non-treated sewage disposal is one of the main impacts to which Imboassica Lagoon has been subjected. The aim of this study was to evaluate the effect of a potential increase in the artificial enrichment on the environmental conditions and zooplankton of this system. To this end, an experimental study was conducted in mesocosms where nutrients were added daily. Bacterial numbers, chlorophyll-a, and picoplanktonic cyanobacteria densities showed an increase with the availability of nutrients. Bacterio- and phytoplankton seemed to be regulated by the rotifers Brachionus rotundiformis and Hexarthra brandorffi.

  12. The effect of wind induced bottom shear stress and salinity on Zostera noltii replanting in a Mediterranean coastal lagoon

    Science.gov (United States)

    Alekseenko, E.; Roux, B.; Fougere, D.; Chen, P. G.

    2017-03-01

    The paper concerns the wind influence on bottom shear stress and salinity levels in a Mediterranean semi-enclosed coastal lagoon (Etang de Berre), with respect to a replanting program of Zostera noltii. The MARS3D numerical model is used to analyze the 3D current, salinity and temperature distribution induced by three meteorological, oceanic and anthropogenic forcings in this lagoon. The numerical model has been carefully validated by comparison with daily observations of the vertical salinity and temperature profiles at three mooring stations, for one year. Then, two modelling scenarios are considered. The first scenario (scen.#1), starting with a homogeneous salinity of S = 20 PSU and without wind forcing, studies a stratification process under the influence of a periodic seawater inflow and a strong freshwater inflow from a hydropower plant (250 m3/s). Then, in the second scenario (scen.#2), we study how a strong wind of 80 km/h can mix the haline stratification obtained at the end of scen.#1. The most interesting results concern four nearshore replanting areas; two are situated on the eastern side of EB and two on the western side. The results of scen.#2 show that all these areas are subject to a downwind coastal jet. Concerning bottom salinity, the destratification process is very beneficial; it always remains greater than 12 PSU for a N-NW wind of 80 km/h and an hydropower runoff of 250 m3/s. Special attention is devoted to the bottom shear stress (BSS) for different values of the bottom roughness parameter (for gravels, sands and silts), and to the bottom salinity. Concerning BSS, it presents a maximum near the shoreline and decreases along transects perpendicular to the shoreline. There exists a zone, parallel to the shoreline, where BSS presents a minimum (close to zero). When comparing the BSS value at the four replanting areas with the critical value, BSScr, at which the sediment mobility would occur, we see that for the smaller roughness values (ranging

  13. Use of advanced earth observation tools for the analyses of recent surface changes in Kalahari pans and Namibian coastal lagoons

    Science.gov (United States)

    Behling, Robert; Milewski, Robert; Chabrillat, Sabine; Völkel, Jörg

    2016-04-01

    The remote sensing analyses in the BMBF-SPACES collaborative project Geoarchives - Signals of Climate and Landscape Change preserved in Southern African Geoarchives - focuses on the use of recent and upcoming Earth Observation Tools for the study of climate and land use changes and its impact on the ecosystem. It aims at demonstrating the potential of recently available advanced optical remote sensing imagery with its extended spectral coverage and temporal resolution for the identification and mapping of sediment features associated with paleo-environmental archives as well as their recent dynamic. In this study we focus on the analyses of two ecosystems of major interest, the Kalahari salt pans as well as the lagoons at Namibia's west coast, that present high dynamic caused by combined hydrological and surface processes linked to climatic events. Multitemporal remote sensing techniques allow us to derive the recent surface dynamic of the salt pans and also provide opportunities to get a detailed understanding of the spatiotemporal development of the coastal lagoons. Furthermore spaceborne hyperspectral analysis can give insight to the current surface mineralogy of the salt pans on a physical basis and provide the intra pan distribution of evaporites. The soils and sediments of the Kalahari salt pans such as the Omongwa pan are a potentially significant storage of global carbon and also function as an important terrestrial climate archive. Thus far the surface distribution of evaporites have been only assessed mono-temporally and on a coarse regional scale, but the dynamic of the salt pans, especially the formation of evaporites, is still uncertain and poorly understood. For the salt pan analyses a change detection is applied using the Iterative-reweighted Multivariate Alteration Detection (IR-MAD) method to identify and investigate surface changes based on a Landsat time-series covering the period 1984-2015. Furthermore the current spatial distribution of

  14. Methane concentration in water column and in pore water of a coastal lagoon (Cabiúnas lagoon, Macaé, RJ, Brazil

    Directory of Open Access Journals (Sweden)

    André Luiz dos Santos Fonseca

    2004-06-01

    Full Text Available The aim of this study was to evaluate methane concentration in water column and pore water at limnetic and littoral regions of a coastal lagoon. At the littoral region samples were taken from three monospecific macrophytes stands (Typha domingensis, Eleocharis interstincta and Potamogeton stenostachys. The methane concentration in the pore water at the littoral region was higher than the concentration found at the limnetic region in each fraction of the sediment. The higher methane concentration in the superficial fraction of the sediment (0-2 cm was shown at the P. stenostachys stand (3.7 mM. It was the only significantly different (p0.05. It could be concluded that there was a high influence of aquatic macrophytes on the pore water methane concentration.O objetivo dessa pesquisa foi determinar a concentração de metano na coluna d'água e na água intersticial do sedimento nas regiões limnética e litorânea de uma lagoa costeira (Lagoa Cabiúnas, Macaé, RJ. Na região litorânea as amostras foram coletadas em três estandes de macrófitas (Typha domingensis, Eleocharis interstincta e Potamogeton stenostachys. A concentração de metano na água intersticial na região litorânea foi maior do que aquela encontrada na região limnética em cada fração do sedimento. A maior concentração de metano na fração superficial do sedimento (0-2 cm foi observada no estande de P. stenostachys (3.7 mM. Este resultado foi o único significativamente diferente (p0.05. Os resultados sugerem que há uma considerável influência das macrófitas aquáticas estudadas na concentração de metano na água intersticial do sedimento.

  15. Water column conditions in a coastal lagoon near Jeddah, Red Sea

    Directory of Open Access Journals (Sweden)

    Alaa M. A. Albarakati

    2012-11-01

    Full Text Available Water column conditions in a lagoon near Jeddah are investigated on the basisof changes in potential energy. Three major factors including balance ofsurface heat at the air-sea interface, wind and tidal mixing are considered.A negative potential energy change dv/dt will developstratification, whereas positive dv/dt will tend to mix the watercolumn. The tidal effect is greater in summer with wind mixing showing nogreat variations. The buoyancy effect of the heat balance at the surface isnegative from April to October. This negative buoyancy effect will tend to developstratification but the positive contributions of wind and tide counteract this andthe water column remains mixed except in September and October, when a weakstratification may develop. Generally, the water column remains practically mixedthroughout the year. The change in heat content of the water column from mid-Aprilto mid-September is about 3.3 × 108 J. During this period the netheat input at the air interface is about 2.0 × 108 J, which isabout 40% less than the heat content of the water column, showing that the heat is advected towards the central area from the shallower periphery of the lagoon.

  16. Identification of Cyanobacteria in a Eutrophic Coastal Lagoon on the Southern Baltic Coast

    Directory of Open Access Journals (Sweden)

    Martin Albrecht

    2017-05-01

    Full Text Available Cyanobacteria are found worldwide in various habitats. Members of the picocyanobacteria genera Synechococcus and Prochlorococcus dominate in oligotrophic ocean waters. Other picocyanobacteria dominate in eutrophic fresh or brackish waters. Usually, these are morphologically determined as species of the order Chroococcales/clade B2. The phytoplankton of a shallow, eutrophic brackish lagoon was investigated. Phytoplankton was dominated by Aphanothece-like morphospecies year-round for more than 20 years, along a trophy and salinity gradient. A biphasic approach using a culture-independent and a culture-dependent analysis was applied to identify the dominant species genetically. The 16S rRNA gene phylogeny of clone sequences and isolates indicated the dominance of Cyanobium species (order Synechococcales sensu Komárek/clade C1 sensu Shih. This difference between morphologically and genetically based species identifications has consequences for applying the Reynolds functional-groups system, and for validity long-term monitoring data. The literature shows the same pattern as our results: morphologically, Aphanothece-like species are abundant in eutrophic shallow lagoons, and genetically, Cyanobium is found in similar habitats. This discrepancy is found worldwide in the literature on fresh- and brackish-water habitats. Thus, most Aphanothece-like morphospecies may be, genetically, members of Cyanobium.

  17. Bioprospecting Sediments from Red Sea Coastal Lagoons for Microorganisms and Their Antimicrobial Potential

    KAUST Repository

    Al-Amoudi, Soha

    2016-12-08

    Since the soils nutrient composition along with the associated biotic and abiotic factors direct the diversity of the contained microbiome and its potential to produce bioactive compounds, many studies have been focused on sediment types with unique features characteristic of extreme environments. Red Sea lagoon ecosystems are environments with such unique features as they are highly saline. However, not much is known about the potential of their microbiomes to produce bioactive compounds. Here, we explored sediment types such as mangrove mud, microbial mat, and barren soil collected from Rabigh harbor lagoon (RHL) and Al-Kharrar lagoon (AKL) as sources for antibiotic bioprospecting. Our antibiotic bioprospecting process started with a metagenomic study that provides a more precise view of the microbial community inhabiting these sites and serves as a preliminary screen for potential antibiotics. Taking the outcomes of the metagenomic screening into account, the next step we established a library of culturable strains from the analyzed samples. We screened each strain from that library for antibiotic activity against four target strains (Staphylococcus aureus ATCC 25923, Escherichia coli dh5 α, Pseudomonas syringae pv. tomato dc3000 and Salmonella typhimurium dt2) and for the presence of polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes known to support synthesis of secondary metabolites that act like antimicrobial agents. The metagenomics study showed a shift in dominant phyla consistent with a historical exposure to hydrocarbon contamination and that AKL unexpectedly displayed more contamination than RHL. This may be due to dominant phyla in AKL being consistent with early hydrocarbon exposure (when contamination levels are still high) and the dominant phyla in RHL being consistent with late hydrocarbon exposure (when contamination levels are lower as a result of an extended period of hydrocarbon degradation). Additionally, RHL samples

  18. Distribution of Escherichia coli in a coastal lagoon (Venice, Italy): Temporal patterns, genetic diversity and the role of tidal forcing.

    Science.gov (United States)

    Perini, L; Quero, G M; García, E Serrano; Luna, G M

    2015-12-15

    Despite its worldwide importance as fecal indicator in aquatic systems, little is known about the diversity of Escherichia coli in the environment and the factors driving its spatial distribution. The city of Venice (Italy), lying at the forefront of a large European lagoon, is an ideal site to study the mechanisms driving the fate of fecal bacteria, due to the huge fluxes of tourists, the city's unique architecture (causing poor efficiency of sewages treatment), and the long branching network of canals crossing the city. We summarize the results of a multi-year investigation to study the temporal dynamics of E. coli around the city, describe the population structure (by assigning isolates to their phylogenetic group) and the genotypic diversity, and explore the role of environmental factors in determining its variability. E. coli abundance in water was highly variable, ranging from being undetectable up to 10(4) Colony Forming Units (CFU) per 100 ml. Abundance did not display significant relationships with the water physico-chemical variables. The analysis of the population structure showed the presence of all known phylogroups, including extra-intestinal and potentially pathogenic ones. The genotypic diversity was very high, as likely consequence of the heterogeneous input of fecal bacteria from the city, and showed site-specific patterns. Intensive sampling during the tidal fluctuations highlighted the prominent role of tides, rather than environmental variables, as source of spatial variation, with a more evident influence in water than sediments. These results, the first providing information on the genetic properties, spatial heterogeneity and influence of tides on E. coli populations around Venice, have implications to manage the fecal pollution, and the associated waterborne disease risks, in coastal cities lying in front of lagoons and semi-enclosed basins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Sediment dynamics of an artificially deepened mesotidal coastal lagoon: An environmental magnetic investigation of Tauranga Harbour, New Zealand

    Science.gov (United States)

    Badesab, Firoz; von Dobeneck, Tilo; Briggs, Roger M.; Bryan, Karin R.; Just, Janna; Müller, Hendrik

    2017-07-01

    Tauranga Harbour, New Zealand's largest barrier-enclosed coastal lagoon, comprises two sub-basins with separate catchments, inlets and tidal channel systems. This study sets out to assess and investigate the sediment dispersal system of Tauranga Harbour using standard environmental magnetic and sedimentological methods. Compilations of rock magnetic and grain size data of surficial sediments collected from inflowing rivers, various estuarine environments (estuaries, tidal flats and tidal channels) and the adjacent nearshore mirror the net and differential sediment fluxes into and through the two sub-basins of this lagoon. For all studied depositional environments, the magnetogranulometric ratios SIRM/κ and ARM/κ are positively correlated with magnetic mineral content (SIRM, ARM, χ) in the sense that larger magnetic particles are associated with higher magnetic enrichment. Grain-size analyses show that magnetic enrichment during particle transport and deposition can result from grain-size as well as from grain-density fractionation. The periodically changing accumulation/erosion conditions provide for a selective retention of specific grain sizes and an enhancement of the heavier magnetic mineral particles. Magnetic crystal size and clastic grain size correlate poorly over the whole study area, but group within similar depositional environments. Coarser magnetic and clastic grain sizes and higher magnetite enrichment in the southern sub-basin can be reconciled with episodic flood runoff of the Wairoa River and a much larger, artificially deepened southern tidal inlet which likely enables higher tidal current velocities. Our approach of combining magnetic and clastic grain-size could be successfully implemented to establish a conceptual model of sediment dynamics and gravitational sorting within Tauranga Harbour.

  20. Global climate change and local watershed management as potential drivers of salinity variation in a tropical coastal lagoon (Laguna de Terminos, Mexico)

    OpenAIRE

    Fichez, Renaud; Archundia, D.; Grenz, C.; Douillet, Pascal; Mendieta, F. G.; Moreno, M. O.; Denis, L.; Esparza, A. C. R.; Zavala-Hidalgo, J.

    2017-01-01

    The wide range of ecological goods and services provided by tropical coastal lagoons and wetlands are under considerable pressure due to the synergistic effects of local anthropogenic impact and global climate change. In transitional waters, salinity is a key driver of ecological processes mostly depending on the balance between marine and river inputs, a balance that can be significantly modified by climate change and by anthropogenic alteration of the watershed. Mesoamerica being considered...

  1. Estimating groundwater discharge in the coastal lagoons of La Palme and Salses-Leucate along the French Mediterranean coastline by using radium isotopes

    Science.gov (United States)

    van Beek, Pieter; Tamborski, Joseph; Bejannin, Simon; Souhaut, Marc; Garcia-Orellana, Jordi; Stieglitz, Thomas; Claude, Christelle; Radakovitch, Olivier; Lacan, François; Crispi, Olivier; Pujo-Pay, Mireille; Conan, Pascal; Caparros, Jocelyne; Guéneuguès, Audrey; Monin, Christophe; Seidel, Jean-Luc; Anschutz, Pierre

    2017-04-01

    Although submarine groundwater discharge (SGD) has been investigated in many places of the world, very few studies were conducted along the French Mediterranean coastline, despite presence of several well-known karstic springs. Almost no information is available on the fluxes of water and chemical elements associated with these systems and on their potential impact on the geochemical cycling and ecosystems of the coastal zones. In this study, we report airborne thermal infrared (TIR) images that allowed us to locate fresh groundwater inputs in the coastal lagoons of La Palme and Salses-Leucate. The four radium isotopes (223Ra, 224Ra, 226Ra, 228Ra) were analyzed in these coastal lagoons and along transects conducted on board RV NEREIS II between the coast and offshore (between 200 m and 8 km). We also analyzed major elements, nutrients (nitrates, phosphates and silicates), DIC, DOC, DON, DOP, as well as several trace elements in these water samples. A mass balance of radium isotopes was used to quantify SGD fluxes and to determine the fluxes of nutrients and other chemical species associated with SGD. Ra isotopes were also used to estimate the residence time of the waters in the lagoons.

  2. Heavy metal contamination of coastal lagoon sediments by anthropogenic activities: the case of Nador (East Morocco)

    Science.gov (United States)

    Bloundi, M. K.; Duplay, J.; Quaranta, G.

    2009-01-01

    Nador lagoon sediments (East Morocco) are contaminated by industrial iron mine tailings, urban dumps and untreated wastewaters from surrounding cities. The lagoon is an ecosystem of biological, scientific and socio-economic interests but its balance is threatened by pollution already marked by biodiversity changes and a modification of foraminifera and ostracods shell structures. The aim of the study is to assess the heavy metal contamination level and mobility by identifying the trapping phases. The study includes analyses by ICP-AES and ICP-MS, of, respectively, major (Si, Al, Mg, Ca, Fe, Mn, Ti, Na, K, P) and trace elements (Sr, Ba, V, Ni, Co, Cr, Zn, Cu, As, Pb, Cd) in sediments and suspended matter, heavy metals enrichment factors calculations and sequential extractions. Results show that sediments contain Zn, Cu, Pb, V, Cr, Co, As, Ni with minimum and maximum concentrations, respectively, of 4-1190 μg/g, 4-466 μg/g, 11-297 μg/g, 11-194 μg/g, 9-139 μg/g, 1-120 μg/g, 4-76 μg/g, 2-62 μg/g. High concentrations in Zn are also present in suspended matter. The enrichment factors show contamination in Zn, Pb and As firstly induced by the mining industry and secondly by unauthorized dumps and untreated wastewaters. Cr and Ni are bound to clays, whereas V, Co, Cu and Zn are related to oxides. Thus, the risk in metal mobility is for the latter elements and lies in the oxidation-reduction-changing conditions of sediments.

  3. Pollen deposition in tauber traps and surface soil samples in the Mar Chiquita coastal lagoon area, pampa grasslands (Argentina

    Directory of Open Access Journals (Sweden)

    Fabiana Latorre

    2010-12-01

    Full Text Available Estimations of airborne pollen loadings deposited in Tauber traps were studied in a coastal lagoon from south-eastern Pampa grasslands, Argentina, in order to assess their relationship with surface samples and to interpret the representativeness of local, regional and extraregional vegetation. Three different environments were considered: a coastal dune barrier with a psammophytic community, a salt marsh with a halophytic community in Mar Chiquita lagoon, and a freshwater community at Hinojales freshwater lake. Based on a record of surface samples taken from a previous paper, a parametric model was built to classify Tauber samples gathered from the natural vegetation communities of the study area. Results revealed that just like their surface counterparts, Tauber trap records qualitatively reflect the predominant vegetation types, although ecological groups feature different quantitative representations depending on the record type. Pollen loadings showed that airborne pollen transport was predominantly of local range, in accordance with previous results from the same study area. Airborne - surface samples relationships enrich our knowledge of the present environment that could be useful to improve paleoecological interpretations of the area.Se estimó el depósito polínico atmosférico de trampas Tauber en una laguna costera del sudeste de la estepa pampeana argentina, con el objetivo de analizar su relación con muestras de polen superficial e interpretar la representatividad de la vegetación local, regional y extraregional. Se consideraron tres ambientes diferentes: una barrera costera de dunas con vegetación psamofítica, la marisma de la laguna costera Mar Chiquita, con vegetación halofítica, y la laguna continental Hinojales, con vegetación hidrofítica. En base a las muestras de superficie y análisis de un trabajo previo, se construyó un modelo paramétrico para clasificar las muestras Tauber tomadas en la vegetación natural del

  4. Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

    Science.gov (United States)

    Zhu, Yafei; McCowan, Andrew; Cook, Perran L. M.

    2017-10-01

    The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes) were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads), which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria). Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

  5. Integrated evaluation of environmental parameters influencing Vibrio occurrence in the coastal Northern Adriatic Sea (Italy) facing the Venetian lagoon.

    Science.gov (United States)

    Caburlotto, Greta; Bianchi, Franco; Gennari, Micol; Ghidini, Valentina; Socal, Giorgio; Aubry, Fabrizio Bernardi; Bastianini, Mauro; Tafi, Mariacarla; Lleo, Maria M

    2012-01-01

    In the marine environment, the persistence and abundance of Vibrio are related to a number of environmental parameters. The influence of the different environmental variables in determining the Vibrio occurrence could be different in the specific geographic areas around the world. Moreover, oceanographic parameters are generally interdependent and should not be considered separately when their influence on bacterial presence and concentration is tested. In this study, an integrated approach was used to identify key parameters determining the abundance of Vibrio spp in marine samples from the Venetian Lagoon in Italy, which is an important area for fish farming and tourism. Multivariate techniques have been adopted to analyze the dataset: using PCA, it was shown that a relatively high proportion of the total variance in this area was mainly due to two independent variables, namely salinity and temperature. Using cluster analysis, it was possible to categorize different groups with homogeneous features as regards space ("stations") and time ("seasons") distribution, as well as to quantify the values of environmental variables and the Vibrio abundances in each category. Furthermore, integrating key environmental factors and bacterial concentration values, it was possible to identify levels of salinity and sea surface temperature which were optimal for Vibrio concentration in water, plankton, and sediment samples. The identification of key environmental variables conditioning Vibrio occurrence should facilitate ocean monitoring, making it possible to predict unexpected variations in marine microflora which determine possible public health risks in coastal areas.

  6. Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

    Directory of Open Access Journals (Sweden)

    Y. Zhu

    2017-10-01

    Full Text Available The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads, which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria. Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

  7. Nitrogen and phosphorus resorption efficiency, and N : P ratios in natural populations of Typha domingensis Pers. in a coastal tropical lagoon

    Directory of Open Access Journals (Sweden)

    Bruno dos Santos Esteves

    2013-06-01

    Full Text Available AIM: We studied nitrogen (N and phosphorus (P resorption patterns in Typha domingensis Pers. in a tropical coastal lagoon during different seasons of throughout one year. METHODS: Resorption of N and P is uttered as resorption efficiency (NRE and PRE, respectively, which may be used as an indicator of a nutrient limitation. Higher resorption efficiency values might indicate limitation of a certain element for the growth of aquatic macrophytes. RESULTS: N was inferred to be less limiting than P for the growth of T. domingensis in Campelo Lagoon, since N content varied less than P content and resorption efficiency of N was lower than that of P and, concomitantly, low resorption efficiency of this element. However, T. domingensis of Campelo Lagoon frequently utilized P that was already present in its tissues, contributing to the longer residence time of this element in system. Green leaves of T. domingensis showed N : P ratio, ranging 49-96, corroborating the inference of P limitation. CONCLUSIONS: N : P ratio and resorption efficiency indicate P limitation by T. domingensis in Campelo Lagoon.

  8. Parasite communities of the neotropical cormorant Phalacrocorax brasilianus (Gmelin) (Aves, Phalacrocoracidae) from two coastal lagoons in Guerrero state, Mexico.

    Science.gov (United States)

    Violante-González, Juan; Monks, Scott; Gil-Guerrero, Salvador; Rojas-Herrera, Agustín; Flores-Garza, Rafael; Larumbe-Morán, Edvino

    2011-11-01

    The parasite community structure of the neotropical cormorant, Phalacrocorax brasilianus, from two lagoons (Coyuca and Tres Palos) from Guerrero state, México, was examined. Fourteen species of adult helminths (6,391 individuals) from 48 cormorants were identified: 9 digeneans, 1 acanthocephalan, 1 cestode, and 3 nematodes. A total of 11 species were collected in Coyuca Lagoon and 12 in Tres Palos Lagoon. Nine species co-occurred in cormorants of both lagoons but, with the exception of Contracaecum multipapillatum and Drepanocephalus olivaceus, species were not equally common in both lagoons. The prevalence values of six species of helminth and the mean abundance of four species varied significantly between lagoons, and C. multipapillatum was numerically dominant in both lagoons. The qualitative similarity between the two communities at the component level was 64%. All cormorants examined were infected, and parasite species richness was 3-5 in Coyuca and 4-9 in Tres Palos lagoon. The results indicate that both communities presented a similar structure at the component level, probably because the cormorants of both lagoons feed on the same species of fish and thus acquire almost the same species of parasites. Differences observed at the infracommunity level were attributed to variations in the degree of dominance of the particular species.

  9. Response of west Indian coastal regions and Kavaratti lagoon to the November-2009 tropical cyclone Phyan

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desai, R.G.P.; Mehra, P.; SanilKumar, V.; Radhakrishnan, K.V.; VijayKumar, K.; AshokKumar, K.; Agarwadekar, Y.; Bhat, U.G.; Luis, R.; Rivankar, P.; Viegas, B.

    ) because of lack of river influx and absence of a sufficiently large land boundary required for the generation and sustenance of wave/wind-driven water mass piling up at the land-sea interface. Keywords: Cyclonic storm `Phyan’, Internet-accessible... in the Lakshadweep Archipelago in the south-eastern Arabian Sea were made with the use of an Internet-accessible real/near-real time reporting Integrated Coastal Observation Network (ICON) designed, developed and established by the National Institute...

  10. Participatory integrated coastal zone management in Vietnam: Theory versus practice case study: Thua Thien Hue province

    Directory of Open Access Journals (Sweden)

    Bieke Abelshausen

    2015-06-01

    Full Text Available Sustainable management processes have undergone a shift from a top-down approach to a bottom-up approach. This bottom-up approach allows for a more apprehensive inclusion of stakeholders. In traditional hierarchical societies a combination of both is considered more desirable. This combination is described as a participatory approach that allows for bi-directional knowledge sharing. The question asked is whether this theoretical approach is viable in practice, taking into account different social, political and cultural influences. Qualitative research in bi-directional knowledge sharing and stakeholder participation in Integrated Coastal Zone Management (ICZM was conducted in the provinces of Thua Thien Hue in Vietnam. Qualitative research was conducted using coding analysis. This analysis showed that in practice a great reluctance for change affects the implementation of ICZM. This reluctance is directly related to the level of power of stakeholders and the level to which stakeholders are embedded in the top-down tradition. Two contradicting results emerged. On the one hand the theoretical understanding of participatory ICZM is highest when reluctance for change is highest and vice versa. On the other hand a decrease in power results in an increase of the sustainability of the implementation of participatory ICZM. This research concluded that a ‘platform or structure’ is essential to achieve sustainability. In the Vietnamese context the tradition of power results in a platform which is both formal and non-formal. A non-formal platform is needed to create social capital, whereas a formal platform will limit the risk for arbitrariness and allow for institutionalisation.

  11. Multi-scale approach to the environmental factors effects on spatio-temporal variability of Chironomus salinarius (Diptera: Chironomidae) in a French coastal lagoon

    Science.gov (United States)

    Cartier, V.; Claret, C.; Garnier, R.; Fayolle, S.; Franquet, E.

    2010-03-01

    The complexity of the relationships between environmental factors and organisms can be revealed by sampling designs which consider the contribution to variability of different temporal and spatial scales, compared to total variability. From a management perspective, a multi-scale approach can lead to time-saving. Identifying environmental patterns that help maintain patchy distribution is fundamental in studying coastal lagoons, transition zones between continental and marine waters characterised by great environmental variability on spatial and temporal scales. They often present organic enrichment inducing decreased species richness and increased densities of opportunist species like C hironomus salinarius, a common species that tends to swarm and thus constitutes a nuisance for human populations. This species is dominant in the Bolmon lagoon, a French Mediterranean coastal lagoon under eutrophication. Our objective was to quantify variability due to both spatial and temporal scales and identify the contribution of different environmental factors to this variability. The population of C. salinarius was sampled from June 2007 to June 2008 every two months at 12 sites located in two areas of the Bolmon lagoon, at two different depths, with three sites per area-depth combination. Environmental factors (temperature, dissolved oxygen both in sediment and under water surface, sediment organic matter content and grain size) and microbial activities (i.e. hydrolase activities) were also considered as explanatory factors of chironomid densities and distribution. ANOVA analysis reveals significant spatial differences regarding the distribution of chironomid larvae for the area and the depth scales and their interaction. The spatial effect is also revealed for dissolved oxygen (water), salinity and fine particles (area scale), and for water column depth. All factors but water column depth show a temporal effect. Spearman's correlations highlight the seasonal effect

  12. Impact of flash flood events on the distribution of organic pollutants in surface sediments from a Mediterranean coastal lagoon (Mar Menor, SE Spain).

    Science.gov (United States)

    León, V M; Moreno-González, R; García, V; Campillo, J A

    2017-02-01

    The influence of flash flood events on the input and distribution of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorinated pesticides (OCPs) in surface sediments from the Mar Menor lagoon were characterized in this study. These contaminants were analyzed in surface water samples collected during two flash flood events in the main surface watercourse which flow into the Mar Menor lagoon. Surface sediments were sampled semiannually before and after flash flood events. The total input of PAHs, OCPs, and PCBs (sorbed + dissolved) during two flash flood events was estimated at 0.98, 1.32, and 0.34 kg, respectively, the main input corresponding to p,p'-DDE (1.00 kg). The distribution of organic contaminants in surface sediments was not homogeneous as a consequence of the presence of many simultaneous sources and different meteorological, hydrodynamic, and physicochemical conditions. As a consequence of flash flood events, p,p'-DDE concentrations in surface sediments increased significantly in the central and south zones of the lagoon. However, in the case of PCBs, a dilution effect was observed in the south zone after such events, reducing the environmental risk. These changes in the pollutant distribution persisted at least 1 year later (autumn 2010), showing that the impact of flood events in the distribution of persistent organic contaminants in Mediterranean coastal lagoons is of relevance according to the ecological risk assessment carried out. The impact of these events should be also considered in other coastal systems, especially in semiarid and semiconfined areas.

  13. Air-Sea CO2 fluxes and NEP changes in a Baja California Coastal Lagoon during the anomalous North Pacific warm condition in 2014

    Science.gov (United States)

    Ávila López, M. D. C.; Martin Hernandez-Ayon, J. M.; Camacho-Ibar, V.; Sandoval Gil, J.; Mejía-Trejo, A.; Félix-Bermudez, A.; Pacheco-Ruiz, I.

    2015-12-01

    The present study examines the temporal variability of seawater carbonate chemistry and air-sea CO2 fluxes (FCO2) in a Baja California Mediterranean-climate coastal lagoon. This study was carried out from Nov-2013 to Nov-2014, a period in which anomalous warm conditions were present in the North Pacific Ocean influenced the local oceanography in the adjacent coastal waters off Baja California. These ocean conditions resulted on a negative anomaly of upwelling index, which led to summer-like season (weak upwelling condition) that could be observed in the response of carbon dynamics and metabolic status in San Quintín Bay. Minor changes in dissolved inorganic carbon (DIC) concentration during spring months (~100 µmol kg-1) where observed and were associated to biological processes within the lagoon. High DIC (~2200 µmol kg-1), pCO2 (~800 μatm), and minimum pH (~7.8) values were observed in summer, reflecting the predominance of respiration processes apparently mostly linked to the remineralization of sedimentary organic matter supplied from macroalgal blooms. San Quintín Bay acted as a weak source of CO2 to the atmosphere during the study period, with maximum value observed in July (~10 mmol C m-2 d-1). Temporal biomass production of macroalgae contributed to about 50% of total FCO2 estimated in spring-summer seasons, that was a potencial internal source of organic matter to fuel respiration processes in San Quintín Bay. Eelgrass metabolism contributes in a lower degree in total FCO2. During the anomalous ocean conditions in 2014, the lagoon switched seasonally between net heterotrophy and net autotrophy during the study period, where photosynthesis and respiration processes in the lagoon were closer to a balance. Whole-system metabolism and FCO2 clearly indicated the strong dependence of San Quintín Bay on upwelling conditions and benthic metabolism activity, which was mainly controlled by dominant primary producer communities.

  14. Impact of recent coastal development and human activities on Nha Trang Bay, Vietnam: evidence from a Porites lutea geochemical record

    Science.gov (United States)

    Nguyen, A. D.; Zhao, J.-x.; Feng, Y.-x.; Hu, W.-p.; Yu, K.-f.; Gasparon, M.; Pham, T. B.; Clark, T. R.

    2013-03-01

    Nha Trang Bay (NTB) is located on the Central Vietnam coast, western South China Sea. Recent coastal development of Nha Trang City has raised public concern over an increasing level of pollution within the bay and degradation of nearby coral reefs. In this study, multiple proxies (e.g., trace metals, rare earth elements (REEs), and Y/Ho) recorded in a massive Porites lutea coral colony were used to reconstruct changes in seawater conditions in the NTB from 1995 to 2009. A 14-year record of REEs and other trace metals revealed that the concentrations of terrestrial trace metals have increased dramatically in response to an increase in coastal development projects such as road, port, and resort constructions, port and river dredging, and dumping activities since 2000. The effects of such developmental processes are also evident in changes in REE patterns and Y/Ho ratios through time, suggesting that both parameters are critical proxies for marine pollution.

  15. Carbon and nitrogen stable isotopes and metal concentration in food webs from a mining-impacted coastal lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Marin-Guirao, Lazaro [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100-Murcia (Spain)], E-mail: lamarin@um.es; Lloret, Javier; Marin, Arnaldo [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100-Murcia (Spain)

    2008-04-01

    Two food webs from the Mar Menor coastal lagoon, differing in the distance from the desert-stream through which mining wastes were discharged, were examined by reference to essential (Zn and Cu) and non-essential (Pb and Cd) metal concentrations and stable isotopes content (C and N). The partial extraction technique applied, which reflects the availability of metals to organisms after sediment ingestion, showed higher bioavailable metal concentrations in sediments from the station influenced by the mining discharges, in agreement with the higher metal concentrations observed in organisms, which in many cases exceeded the regulatory limits established in Spanish legislation concerning seafood. Spatial differences in essential metal concentrations in the fauna suggest that several organisms are exposed to metal levels above their regulation capacity. Differences in isotopic composition were found between both food webs, the wadi-influenced station showing higher {delta}{sup 15}N values and lower {delta}{sup 13}C levels, due to the discharge of urban waste waters and by the entrance of freshwater and allochthonous marsh plants. The linear-regressions between trophic levels (as indicated by {delta}{sup 15}N) and the metal content indicated that biomagnification does not occur. In the case of invertebrates, since the 'handle strategy' of the species and the physiological requirements of the organisms, among other factors, determine the final concentration of a specific element, no clear relationships between trophic level and the metal content are to be expected. For their part, fish communities did not show clear patterns in the case of any of the analyzed metals, probably because most fish species have similar metal requirements, and because biological factors also intervened. Finally, since the study deals with metals, assumptions concerning trophic transfer factors calculation may not be suitable since the metal burden originates not only from the prey but

  16. Understanding smallholder farmers’ capacity to respond to climate change in a coastal community in Central Vietnam

    NARCIS (Netherlands)

    Phuong, Le Thi Hong; Biesbroek, G.R.; Sen, Le Thi Hoa; Wals, Arjen E.J.

    2017-01-01

    Climate change as expressed by erratic rainfall, increased flooding, extended droughts, frequency tropical cyclones or saline water intrusion, poses severe threats to smallholder farmers in Vietnam. Adaptation of the agricultural sector is vital to increase the resilience of smallholder farmers’

  17. Changes in bacterial community metabolism and composition during the degradation of dissolved organic matter from the jellyfish Aurelia aurita in a Mediterranean coastal lagoon.

    Science.gov (United States)

    Blanchet, Marine; Pringault, Olivier; Bouvy, Marc; Catala, Philippe; Oriol, Louise; Caparros, Jocelyne; Ortega-Retuerta, Eva; Intertaglia, Laurent; West, Nyree; Agis, Martin; Got, Patrice; Joux, Fabien

    2015-09-01

    Spatial increases and temporal shifts in outbreaks of gelatinous plankton have been observed over the past several decades in many estuarine and coastal ecosystems. The effects of these blooms on marine ecosystem functioning and particularly on the dynamics of the heterotrophic bacteria are still unclear. The response of the bacterial community from a Mediterranean coastal lagoon to the addition of dissolved organic matter (DOM) from the jellyfish Aurelia aurita, corresponding to an enrichment of dissolved organic carbon (DOC) by 1.4, was assessed for 22 days in microcosms (8 l). The high bioavailability of this material led to (i) a rapid mineralization of the DOC and dissolved organic nitrogen from the jellyfish and (ii) the accumulation of high concentrations of ammonium and orthophosphate in the water column. DOM from jellyfish greatly stimulated heterotrophic prokaryotic production and respiration rates during the first 2 days; then, these activities showed a continuous decay until reaching those measured in the control microcosms (lagoon water only) at the end of the experiment. Bacterial growth efficiency remained below 20%, indicating that most of the DOM was respired and a minor part was channeled to biomass production. Changes in bacterial diversity were assessed by tag pyrosequencing of partial bacterial 16S rRNA genes, DNA fingerprints, and a cultivation approach. While bacterial diversity in control microcosms showed little changes during the experiment, the addition of DOM from the jellyfish induced a rapid growth of Pseudoalteromonas and Vibrio species that were isolated. After 9 days, the bacterial community was dominated by Bacteroidetes, which appeared more adapted to metabolize high-molecular-weight DOM. At the end of the experiment, the bacterial community shifted toward a higher proportion of Alphaproteobacteria. Resilience of the bacterial community after the addition of DOM from the jellyfish was higher for metabolic functions than diversity

  18. Effects of organic pollution in the distribution of annelid communities in the Estero de Urías coastal lagoon, Mexico

    Directory of Open Access Journals (Sweden)

    Agustín Ferrando

    2011-06-01

    Full Text Available The Estero de Urías coastal lagoon is subjected to several anthropogenic activities and has been characterized since 1997 through the study of benthic fauna. We analyzed the spatial and temporal distribution of annelids and their relationships with environmental variables (depth, sediment temperature, grain size and organic matter in order to determine the current degree of perturbation. Density, species richness, diversity, dominance, biomass, and the application of classification and ordination techniques allowed us to distinguish 5 zones: 1 a non-perturbed zone at the mouth of the lagoon, 2 a slightly perturbed zone surrounded by mangroves and shrimp farms, 3 a temporarily perturbed zone close to the effluent of the thermoelectric plant, 4 a perturbed zone in front of the slaughterhouse and fish factory, and 5 a very perturbed zone subjected to sewage and industrial input. Only minor changes in granulometry and faunal composition were observed in comparison with previous data from the same area, suggesting that the lagoon is still perturbed due to the effect of anthropogenic activities.

  19. Metabolism of a nitrogen-enriched coastal marine lagoon during the summertime

    Science.gov (United States)

    Howarth, Robert W.; Hayn, Melanie; Marino, Roxanne M.; Ganju, Neil; Foreman, Kenneth H.; McGlathery, Karen; Giblin, Anne E.; Berg, Peter; Walker, Jeffrey D.

    2014-01-01

    We measured metabolism rates in a shallow, nitrogen-enriched coastal marine ecosystem on Cape Cod (MA, USA) during seven summers using an open-water diel oxygen method. We compared two basins, one directly receiving most of the nitrogen (N) load (“Snug Harbor”) and another further removed from the N load and better flushed (“Outer Harbor”). Both dissolved oxygen and pH varied greatly over the day, increasing in daylight and decreasing at night. The more N-enriched basin frequently went hypoxic during the night, and the pH in both basins was low (compared to standard seawater) when the oxygen levels were low, due to elevated carbon dioxide. Day-to-day variation in gross primary production (GPP) was high and linked in part to variation in light. Whole-ecosystem respiration tended to track this short-term variation in GPP, suggesting that respiration by the primary producers often dominated whole-system respiration. GPP was higher in the more N-loaded Snug Harbor. Seagrasses covered over 60 % of the area of the better-flushed, Outer Harbor throughout our study and were the major contributors to GPP there. Seagrasses covered 20 % of the area in Snug Harbor for the first 5 years of our study, and their contribution to GPP was relatively small. The seagrasses in Snug Harbor died off completely in the 6th year, but GPP remained high then and in the subsequent year. Overall, rates of phytoplankton GPP were relatively low, suggesting that benthic micro- and macro-algae may be the dominant primary producers in Snug Harbor in most years. Net ecosystem production in both Snug Harbor and the Outer Harbor was variable from year to year, showing net heterotrophy in some years and net autotrophy in others, with a trend towards increasing autotrophy over the 7 years reported here.

  20. Fish composition and prey utilization of the black skimmer (Rynchops niger) in mar Chiquita coastal lagoon, Argentina

    National Research Council Canada - National Science Library

    Mariano-Jelicich, Rocío; García, Germán; Favero, Marco

    2014-01-01

    Lagoons along the western coast of the South Atlantic Ocean shelter high densities of juvenile fish and are key areas for several seabirds that rely on the resources offered by this kind of ecosystem...

  1. Patterns in nutrient limitation and chlorophyll a along an anthropogenic eutrophication gradient in French Mediterranean coastal lagoons

    National Research Council Canada - National Science Library

    Souchu, Philippe; Bec, Beatrice; Smith, Val H; Laugier, Thierry; Fiandrino, Annie; Benau, Laurent; Orsoni, Valerie; Collos, Yves; Vaquer, Andre

    2010-01-01

    A cross-ecosystem comparison of data obtained from 20 French Mediterranean lagoons with contrasting eutrophication status provided the basis for investigating the variables that best predict chlorophyll a (Chl...

  2. Bioavailability of cadmium, copper, mercury, lead, and zinc in subtropical coastal lagoons from the southeast Gulf of California using mangrove oysters (Crassostrea corteziensis and Crassostrea palmula).

    Science.gov (United States)

    Páez-Osuna, Federico; Osuna-Martínez, Carmen C

    2015-02-01

    Cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn) were assessed in the edible tissues of Crassrotrea corteziensis oysters collected during the rainy and dry seasons in 27 sites from 8 coastal lagoons of the southeast Gulf of California. In addition, C. palmula oysters were sampled at 9 sites from the same mangrove roots where C. corteziensis oysters were collected. Metal analyses were performed by flame atomic absorption spectrophotometry (Cd, Cu, and Zn), graphite furnace (Pb), and cold vapor detection (Hg). The obtained mean levels were (µg g(-1) dry weight) as follows: Cd 6.05 ± 2.77, Cu 60.0 ± 33.4, Hg 0.38 ± 0.17, Pb 1.11 ± 0.63, and Zn 777 ± 528 µg g(-1). For all metals except Hg, the concentrations were greater during dry season than during rainy seasons. The high levels, particularly that for Cd, were related to upwelling along the eastern Gulf of California. High Hg levels in the rainy season were associated with the transport of materials from the watershed to the lagoon. Shrimp farming, agriculture, and other sources were considered as potential sources to explain the differences in metal bioavailability in the 8 lagoons. The mean concentrations of Cd (Santa María-La Reforma lagoon), Cu [San Ignacio-Navachiste-El Macapule (SINM), Urías (URI), and Altata-Ensenada del Pabellón lagoons], and zinc (Zn) (URI, Santa María-Ohuira-Topolobampo, El Colorado, and SINM lagoons) during the dry season were greater than the maximum permissible limits. C. palmula collected in 8 sites where they were present simultaneously with C. corteziensis had consistently greater metal levels than C. corteziensis, but correlation analyses showed a high and significant (P < 0.05) correlation between metal concentrations in both species. The correlation equations obtained are useful where the same species is not distributed and is necessary to compare results from distinct regions.

  3. Spatial and temporal variation of fish assemblages in a coastal lagoon of the Biosphere Reserve La Encrucijada, Chiapas, Mexico

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    Ernesto Velázquez-Velázquez

    2008-06-01

    Full Text Available Composition and abundance of the ichthyofauna in estuarine and coastal lagoon systems of the South Pacific in Mexico have been scarcely studied. In particular, there is a lack of information on how environmental variables determine the spatio-temporal structure of fish assemblages in those habitats. In this study, fishes were sampled by drop net during twelve months (May 2004 -April 2005 in 22 sites distributed along the Carretas-Pereyra lagoon, located in the Biosphere Reserve La Encrucijada, Chiapas, Mexico. We recorded 11 797 individuals (40 species, in 30 genera and 21 families. Dormitator latifrons was the most dominant species in terms of the Importance Value index, IV (23.05 %, followed by Lile gracilis (10.31 %, Poecilia sphenops (8.60 % and Poecilia butleri (7.30 %. D. latifrons also accounted for more than one half of the total biomass (50.14 %. Species richness and Shannon-Wiener’s diversity indexes showed similar temporal fluctuations, reaching their highest values during the dry season. The system evidenced temporal variations in salinity, having observed four different regimes: freshwater, oligohaline, mesohaline and polyhaline. Mean richness and diversity indexes achieved their highest values during the mesohaline period. On the other hand, mean abundances (CPUE were highest during the freshwater period. Canonical correspondence analysis (CCA indicated that salinity and temperature were the most important environmental parameters affecting associations of fishes in terms of their abundances. Correlation analyses revealed that among the environmental variables measured in this study, transparency showed the most significant negative correlation with fish richness and Shannon-Wiener’s diversity index. At a local scale, results suggest that spatial and temporal distribution of fish assemblages are determined by differences in the regimes of salinity and transparency, primarily driven by freshwater input from rivers. Rev. Biol

  4. Anthropogenic disturbance and spatial heterogeneity of macrobenthic invertebrate assemblages in coastal lagoons: the study case of Pialassa Baiona (northern Adriatic Sea)

    Science.gov (United States)

    Ponti, Massimo; Casselli, Chiara; Abbiati, Marco

    2011-03-01

    The distribution patterns of macrobenthic invertebrate assemblages at different spatial scales and in relation to natural and anthropogenic disturbance gradients were investigated in the Pialassa Baiona, a eutrophic and polluted brackish coastal lagoon located along the Italian coast of the northern Adriatic Sea. This coastal lagoon shows a complex physiography with several shallow water ponds and channels separated by discontinuous artificial embankments. Environmental variables and macrobenthic invertebrate assemblages showed higher heterogeneity at small spatial scale (i.e. within channels and ponds). Distinction between channels and ponds is only weakly supported by the distribution patterns of macrobenthic assemblages. Depth was the major factor in structuring benthic communities within ponds, while species distributions along the channels were strongly correlated with the anthropogenic disturbance gradient. Anthropogenic disturbance mainly affected species richness, which was inversely correlated with the organic carbon contents in the sediments and the water surface temperature, which is affected by the input of cooling water from two thermal power plants. Some opportunistic species, like the polychaetes Streblospio shrubsolii and Capitella capitata, were more abundant in the southern polluted areas. In particular, the abundance of S. shrubsolii significantly increased with organic carbon contents in the sediments and water surface temperature, while C. capitata was more abundant in the warmed sites and close to sewages. Conversely, the abundance of the amphipod Corophium insidiosum was inversely related to organic carbon contents.

  5. Presence and distribution of current-use pesticides in surface marine sediments from a Mediterranean coastal lagoon (SE Spain).

    Science.gov (United States)

    Moreno-González, R; León, V M

    2017-03-01

    The spatial and seasonal distributions of current-use pesticides (CUPs), including triazines, organophosphorus pesticides, and tributylphosphate, were characterized in surface sediments from the Mar Menor lagoon during 2009 and 2010. The impact of two flash flood events on the input of CUPs and their distribution in the lagoon were also assessed. The total (dissolved + sorbed phase) input of CUPs in the two flash floods through the El Albujón watercourse into the lagoon was estimated at 38.9 kg, of which 9.9 kg corresponded to organophosphorus pesticides and 5.5 kg to triazines. CUP distribution onto sediments was not homogeneous in the lagoon due to the different contaminant sources, sediment types, and the physicochemical and hydrodynamic conditions of the Mar Menor lagoon. Thirteen CUPs were detected in 2009 and 19 in 2010, including mainly herbicides, insecticides, and the additive tributylphosphate. Mean CUP concentrations in the lagoon were generally below 20 ng g(-1), except for chlorpyrifos and tributylphosphate in 2010. The highest concentrations were detected in depositional areas of the lagoon, in the area of influence of the El Albujón watercourse and other wadis with groundwater contributions such as El Mirador (north) and Los Alcázares (east) and that of marine water from El Estacio channel. In fact, the maximum concentration was detected close to El Albujón watercourse (chlorpyrifos, 102.8 ng g(-1) dry weight). Four herbicides, two insecticides, two fungicides, and tributylphosphate showed a risk quotient higher than 1, with that for chlorpyrifos ranging from 96 to 35,200 after flash flood events.

  6. Patterns and Processes of Chasmagnathus granulata and Cyrtograpsus angulatus (Brachyura: Grapsidae) Recruitment in Mar Chiquita Coastal Lagoon, Argentina

    Science.gov (United States)

    Luppi, T. A.; Spivak, E. D.; Anger, K.; Valero, J. L.

    2002-08-01

    Recruitment patterns of crabs and other benthic invertebrates with planktonic larvae are determined by a combination of pre- and post-settlement factors. Recruitment is considered settlement limited when there is a positive correlation between the postlarvae available in the water column and the number of recruits, and regulated when abundance of individuals is mainly affected by post-settlement factors, such as competence and inter or intraspecific predation. Temperate southwestern Atlantic saltmarshes are inhabited by Cyrtograpsus angulatus and Chasmagnathus granulata, two intertidal grapsid crabs. These crabs are considered key species in the ecosystem in Mar Chiquita coastal lagoon, Buenos Aires, Argentina. In this work, we compare the recruitment pattern of Cyrtograpsus angulatus and Chasmagnathus granulata on the basis of a 3-year sampling programme. Furthermore, we examine experimentally, in laboratory and field, settlement and postsettlement processes that can help explain these patterns: habitat selection, intra- and inter-cohort cannibalism and predator avoidance behaviour. Finally, we integrate our results with the previous knowledge about distribution, growth and reproductive biology of both species, to propose a model of recruitment of each species. Both species had a consistent recruitment pattern through 3 years. Recruitment of both species started at the beginning of summer, and continued to autumn, but recruits were present until the beginning of spring. Densities of recruits and juveniles of C. angulatus were not correlated, whereas, there was a relationship between abundance of recruits and juveniles of C. granulata. In the field, recruits of C. angulatus suffered high mortality caused by intra- and inter-cohort cannibalism. Megalopae of C. angulatus selected a substrate (crevices in Ficopomatus enigmaticus reef) that gave them refuge against cannibals. First crabs of C. granulata selected adult conspecific substrate (mud from adult habitats

  7. 'Because I am a man, I should be gentle to my wife and my children': positive masculinity to stop gender-based violence in a coastal district in Vietnam

    NARCIS (Netherlands)

    Hoang, T.A.; Quach, T.T; Tran, T.T.

    2013-01-01

    Despite the efforts of the government to promote gender equality in Vietnam, gender-based violence is still a critical issue. This article explores a pilot project, the Responsible Men Club, developed and implemented in a coastal district in Vietnam from 2010 to 2012 to work with men to stop

  8. Alterations in macroinvertebrate spatial patterns in coastal lagoons: Óbidos (NW coast of Portugal) 1984 versus 2002

    Science.gov (United States)

    Rodrigues, Ana Maria; Quintino, Victor; Pereira, Fábio; Freitas, Rosa

    2012-09-01

    The macroinvertebrate spatial distribution patterns in the Lagoon of Óbidos were studied in 1984 and revisited in 2002. The overall surficial sediments and benthic community patterns show consistent similarities in the two sampling periods, but also important differences. The lagoon is relatively shallow, with about 1/3 of the area covered with extensive intertidal sand banks. These are interrupted by a navigation channel bordering the northern margin (1984) and, following dredging operations, a new navigation channel was opened along the southern margin (2002). The sediments in the navigation channels were coarser and with less percentage of fines in 2002 than in 1984. Arthropods dominated the species richness and abundance in 1984, but were much less important in 2002, when the community was dominated by molluscs and annelids, both in species numbers as well as in abundance. In 1984, the structure of the macrofauna communities closely followed a general model proposed for Atlantic and Mediterranean lagoons, with the marine, the transition and the lagoon communities occupying very well defined areas. This gradient was in accordance with an increase in the fines and organic matter content directed inwards allowing for the coexistence of several characteristic lagoon species with others characteristic of organic enriched sediments. In 2002 this spatial pattern is still recognized but the marine and the transition communities are spatially mixed, occupying both the entrance region and the navigation channels, whereas the characteristic lagoon community identified in 1984 was only recognized in a group of sites located along the southern margin in 2002. Several species show very important changes in their distribution extent in the lagoon system. These changes essentially show a generalized inward expansion of the distribution range of the marine species, in agreement with a larger influence of marine conditions toward the inner areas of the lagoon. This study shows

  9. Metabolomic responses in caged clams, Ruditapes decussatus, exposed to agricultural and urban inputs in a Mediterranean coastal lagoon (Mar Menor, SE Spain).

    Science.gov (United States)

    Campillo, Juan A; Sevilla, Angel; Albentosa, Marina; Bernal, Cristina; Lozano, Ana B; Cánovas, Manuel; León, Víctor M

    2015-08-15

    The Mar Menor is a coastal lagoon affected by the growth of intensive agriculture and urban development in the surrounding area. Large amounts of chemical pollutants from these areas are discharged into El Albujón, a permanent water-course flowing into the lagoon. Biomarkers such as the activity of acetylcholinesterase or antioxidant enzymes have been previously tested in this lagoon demonstrating the presence of neurotoxicity and oxidative stress in clams transplanted in sites affected by the dispersion of the effluent from El Albujón. To complete this traditional toxicology work, a metabolomic profiling of these transplanted organisms has been carried out for the detection of metabolic biomarkers induced by agricultural/urban pollutants. More than 70 metabolites have been quantified using a targeting metabolomics platform based on HPLC-MS. The intracellular metabolic pattern was analyzed by PCA from the digestive gland of clams after 7 and 22 days of transplantation. Results showed a different profile of metabolite between organisms collected from control and exposed sites. At the shorter exposure time, there was an increase in several metabolites in the latter when compared with those from control sites, whereas metabolic profiling at 22 days showed that those metabolites were drastically diminished, with even lower levels than at control sites. These metabolites included: (i) 12 amino acids from the 21 proteogenic and HomoSer, (ii) osmotic protectants such as γ-butyrobetaine and taurine and (iii) nucleotides such as ITP. Regarding sulfur-containing molecules, taurine could be highlighted as a potential biomarker since its concentration was reduced by more than 30 times after 22 days of exposure, whereas the antioxidant glutathione remained constant in the organisms from both control and exposed sites. Although targeted metabolomics has been shown as an early technique of pollutant effect detection, the two-phase pattern could highlight a more complicated

  10. Export of materials along a tidal river channel that links a coastal lagoon to the adjacent sea

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    Javier Aldeco Ramírez

    2012-09-01

    Full Text Available Intratidal variability and flux of salt, chlorophyll-a and suspended materials were evaluated in a shallow tropical tidal channel linking a coastal lagoon to the western Gulf of Mexico. Velocity, temperature and conductivity were used to calculate the fluxes. Data were recorded during three tidal velocity cycles (tvc under extreme river discharge conditions. Chlorophyll-a and suspended materials were determined below the surface. In both seasons (dry and rainy, the flow was ebb-dominated and with longer duration than when in flood. Maximum current velocities were 0.30 m s-1 in May (dry season and 0.60 m s-1 in September (rainy season. In the dry season the mean chlorophyll-a export was of 7.56 Kg over tvc while the import was of 3.32 Kg. In the rainy season mean export (47.3 Kg was 6 times greater than the import (7.93 Kg over tvc. Phytoplankton was dominated by organisms of marine origin. The mean of exported, suspended materials in the rainy season (111.3 Kg was 4.6 times greater (859 Kg than that in the dry season (184.7 Kg over tvc. Tidal velocity asymmetry is an effective mechanism of exportation, introducing relatively warm and saltier water into the river through the tidal channel.A variabilidade intramaré, o fluxo de salinidade, a clorofila-a e material em suspensão foram avaliados em um canal superficial de maré tropical em uma lagoa costeira ao oeste do Golfo do México. Os dados de velocidade, temperatura e condutividade foram usados para cálculo dos fluxos durante três ciclos de velocidades das marés (tvc sob condições extremas de descarga. A Clorofila-a e material em suspensão foram determinados abaixo em subsuperfície. Em ambas as estações (seca e chuvosa, o fluxo dominante foi durante o refluxo e com duração maior durante o fluxo de entrada. A máxima velocidade encontrada foi 0.30 m s-1 em maio (estação seca e 0.60 m s-1 em setembro (estação chuvosa. Durante a época seca foram exportadas 7.56 Kg de clorofila

  11. Influence of piers on functional groups of benthic primary producers and consumers in the channel of a subtropical coastal lagoon

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    Paulo Roberto Pagliosa

    2012-03-01

    Full Text Available Artificial habitats have become common in coastal areas worldwide and may influence the structure and functioning of benthic ecosystems. We analyze the influence of piers on the benthic morphofunctional groups of rocky seaweeds and of soft bottom macrofauna in the channel of Conceição Lagoon (southern Brazil. The main impact is a reduction in the luminosity available for photosynthetic activity which is directly related to a decrease in the biomasses of sediment microphytobenthos and of more highly structured macroalgae life-forms. Contrary to expectations, the morphotypes of potentially high biomass productivity, such as articulated coralline, corticated and leathery macroalgae, were in general less abundant and the low biomass foliose and filamentous macroalgae occurred in reference areas but not under the piers. The piers' effects on motile epifauna and infauna functional groups were site-specific and probably related to the general reduction in primary producer organisms in the new habitats. The discretely motile infauna was the only functional group able to thrive under the piers due to their reduced motility and fragile morphological structures, being benefited by the shelter provided by the artificial habitats. Our results showed that the piers might have a negative effect on the base-trophic level organisms responsible for bottom-up controls.Hábitats artificiais têm se tornado comum em áreas costeiras no mundo todo, podendo influenciar a estrutura e funcionamento de ecossistemas bênticos. Nós analisamos a influência de trapiches nos grupos morfofuncionais bênticos de algas associadas a substrato consolidado e de macrofauna em substrato inconsolidado, no canal da Lagoa da Conceição (sul do Brasil. O principal impacto da presença de trapiches é a redução da irradiação disponível para atividade fotossintética, o que está diretamente relacionado com o decréscimo na biomassa microfitobentônica no sedimento e de macroalga

  12. Impacts of coastal upwelling off east Vietnam on the regional winds system: An air-sea-land interaction

    Science.gov (United States)

    Zheng, Zhe-Wen; Zheng, Quanan; Kuo, Yi-Chun; Gopalakrishnan, Ganesh; Lee, Chia-Ying; Ho, Chung-Ru; Kuo, Nan-Jung; Huang, Shih-Jen

    2016-12-01

    In this study, we analyze the influence of coastal upwelling off southeast Vietnam (CUEV) on local wind field using numerical simulations based on atmospheric model of Weather Research and Forecasting (WRF). Several scenarios are simulated by forcing identical model configurations with different SST fields. Based on simulation results, the relationship between CUEV and reduction of wind forcing is numerically evidenced. With the influence of a typical cold patch with a temperature drop of 3-5 °C, the local wind speeds can drop to less than 70% of original level. We find that the mechanism of response of the wind reduction to CUEV is enhancement of sea-breeze induced wind modulation. Onshore sea-breeze will enhance, while the contrast between land and sea is even more striking due to the contribution of a distinct coastal upwelling. This implies that air-sea-land interaction dominates the process of local wind system modulation in response to transient CUEV. This result sheds a new light on the air-sea interaction process within the SCS basin.

  13. Occurrence and seasonal distribution of polycyclic aromatic hydrocarbons and legacy and current-use pesticides in air from a Mediterranean coastal lagoon (Mar Menor, SE Spain).

    Science.gov (United States)

    Carratalá, A; Moreno-González, R; León, V M

    2017-01-01

    The occurrence and seasonal distribution of polycyclic aromatic hydrocarbons (PAHs) and legacy and current-use pesticides (CUPs) in air were characterized around the Mar Menor lagoon using both active and passive sampling devices. The seasonal distribution of these pollutants was determined at 6 points using passive samplers. Passive sampler sampling rates were estimated for all detected analytes using an active sampler, considering preferentially winter data, due to probable losses in active sampling during summer (high temperatures and solar irradiation). The presence of 28 compounds (14 CUPs, 11 PAHs and 3 organochlorinated pesticides) were detected in air by polyurethane passive sampling. The most commonly detected contaminants (>95% of samples) in air were chlorpyrifos, chlorpyrifos-methyl and phenanthrene. The maximum concentrations corresponded to phenanthrene (6000 pg m(-3)) and chlorpyrifos (4900 pg m(-3)). The distribution of contaminants was spatially and seasonally heterogeneous. The highest concentrations of PAHs were found close to the airport, while the highest concentrations of pesticides were found in the influence area of agricultural fields (western stations). PAH and herbicide concentrations were higher in winter than in the other seasons, although some insecticides such as chlorpyrifos were more abundant in autumn. The presence of PAHs and legacy and current-use pesticides in air confirmed their transference potential to marine coastal areas such as the Mar Menor lagoon. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Seasonal variations of selected herbicides and related metabolites in water, sediment, seaweed and clams in the Sacca di Goro coastal lagoon (Northern Adriatic).

    Science.gov (United States)

    Carafa, R; Wollgast, J; Canuti, E; Ligthart, J; Dueri, S; Hanke, G; Eisenreich, S J; Viaroli, P; Zaldívar, J M

    2007-11-01

    This study assesses the status of Sacca di Goro coastal lagoon (Northern Adriatic, Italy) with respect to watershed pollution. Because 80% of its watershed is devoted to agriculture, plant protection products and their metabolites were found in the water column, sediments (the upper 0-15 cm layer), macroalgae (Ulva rigida) and clams (Tapes philippinarum). Five seasonal sampling campaigns were performed from May 2004 to April 2005 and concentrations measured in five stations in the lagoon and six in the watershed. Relatively high concentrations of the s-triazine - terbuthylazine -, urea herbicides - diuron - and alachlor were detected through the year mainly at stations directly influenced by the Po di Volano inflow. The concentrations of products in use follow a clear seasonal pattern with spring peaks. This pattern is also visible in the sediments as well as in biota. Among metabolites, hydroxylated compounds prevailed, often with concentrations greater than those of the parent compounds. For the most part of the year, the concentrations in biota were close to detection limits, with concentration peaks in spring.

  15. Impacts of saline water irrigation and shrimp pond discharges on the surrounding waters of a coastal district in the Mekong delta of Vietnam

    OpenAIRE

    Tho, N.; R. Merckx; Ut, V.N.

    2014-01-01

    This study discusses impacts of saline water irrigation and shrimp pond discharges on the surrounding waters in the coastal Cai Nuoc district, Mekong delta of Vietnam where the landscape was re-shaped by shrimp aquaculture since 2000. Sampling took place at the end of the wet season of 2009 in the district (as aquaculture sites) and a nearby freshwater-dominated reference site. The aquaculture sites showed significantly higher salinities and organic loadings (biochemical oxygen demand, chemic...

  16. Assessment of sediment metal contamination in the Mar Menor coastal lagoon (SE Spain: Metal distribution, toxicity, bioaccumulation and benthic community structure

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available The Mar Menor coastal lagoon is one of the largest of the Mediterranean Sea. Ancient mining activities in the mountains near its southern basin have resulted in metal contamination in the sediment. The metal bioavailability of these sediments was determined through laboratory toxicity bioassays using three Mediterranean sea urchin species and two amphipod species, and by means of field bioaccumulation measurements involving the seagrass Cymodocea nodosa. The effect of sediment metal contamination on benthic communities was assessed through benthic infaunal analyses, applying classical descriptive parameters and multivariate techniques. The sediments affected by the mining activities presented high levels of toxicity and metals were also accumulated in the seagrass tissues, pointing to metal bioavailability. Although the classical benthic indices were not clear indicators of disturbance, the multivariate techniques applied provided more consistent conclusions.

  17. X-ray microtomography characterization of carbonate microbialites from a hypersaline coastal lagoon in the Rio de Janeiro State—Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Machado, A.S., E-mail: alemachado@lin.ufrj.br [Laboratório de Geologia Sedimentar—IGEO, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Laboratório de Instrumentação Nuclear—COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Dal Bó, P.F.F. [Laboratório de Geologia Sedimentar—IGEO, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Lima, I. [Laboratório de Instrumentação Nuclear—COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Borghi, L. [Laboratório de Geologia Sedimentar—IGEO, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Lopes, R. [Laboratório de Instrumentação Nuclear—COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil)

    2015-06-01

    The objective of the present study is to apply the micro-CT technique to assess recent microbialite samples from a hypersaline coastal lagoon in the Rio de Janeiro State. The study comprises structural assessment, mineralogical characterization and porosity distribution of each sample. Micro-CT is increasingly present in geological reservoir analyses, and has advantages over other laboratory techniques since it is non-invasive and allows 2D/3D visualization of inner structures without previous preparation method, such as slabbing, polishing, thinning or impregnation. This technique renders structural analyses which can be spatially resolved to a scale of micrometers. Results show that micro-CT technique is also adequate for the characterization of carbonate microbialites, providing excellent high resolution 3D images, that enabled to distinguish different mineralogies and porosity distribution beyond it is inner structure.

  18. Abundance and distribution of Portunidae larval phases (Crustacea: Brachyura in the estuarine and coastal region of the Patos Lagoon, southern Brazil

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    Rony Roberto Ramos Vieira

    Full Text Available ABSTRACT: The abundance and distribution of larval phases of the Portunidae found in the estuary of the Patos Lagoon and the coastal region were studied during two years (1995 and 1999. A conical net (165 cm long, 60 cm mouth, and 330 µm mesh equipped with a flowmeter was towed for three minutes at 2 knots at six stations within the estuary and four stations in the coastal region. Samplings were carried out on the surface and near the bottom. At each sampling location, the salinity and temperature were also recorded. In 1995, the zoeae of Arenaeus cribrarius (Lamarck, 1818, Callinectes sapidus Rathbun, 1896 and Achelous spinicarpus Stimpson, 1871 were caught, resulting in a total abundance of 121.98 ind.100 m-3 (90.95 ind.100 m-3 on the surface and 31.03 ind.100 m-3 near the bottom. A total of 452.27 ind.100 m-3 were caught in the megalopa phase (13.49 ind.100 m-3 on the surface and 438.78 ind.100 m-3 near the bottom. In 1999, only zoeae of C. sapidus were caught, resulting in a total abundance of 419.78 ind.100 m-3 (386.98 ind.100 m-3 on the surface and 32.8 ind.100 m-3 near the bottom. Megalopae of these three species were caught, resulting in a total abundance of 179.91 ind.100 m-3 (25.38 ind.100 m-3 on surface and 154.53 ind.100 m-3 near the bottom. Summer was the season with the highest abundance of larvae in both years. During spring and summer, spawning was observed in the estuarine region of the Patos Lagoon.

  19. Biodiversity effects of benthic ecosystem engineers on the spatial patterns of sediment CH4 concentration in an urban Neotropical coastal lagoon

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    Adriano Caliman

    Full Text Available AIM: Biodiversity of sediment bioturbators has been shown to be important for to the magnitude and stability of benthic-pelagic processes. However, no study to date has evaluated the importance of the biodiversity of benthic invertebrate bioturbators to the spatial patterns of sediment CH4 concentration ([CH4]. Here we conducted a laboratorial experiment to test the following predictions: (1 Bioturbator species richness will reduce the sediment [CH4]; (2 individual bioturbator species (i.e. species composition will have different effects on sediment [CH4]; (3 and both the effects of bioturbator species richness and composition on sediment [CH4] will be dependent on sediment depth. METHODS: We manipulated the number and composition of three functional divergent benthic invertebrate bioturbators species that are widespread in South Atlantic coastal lagoons, in laboratorial sediment chambers containing the sediment and water of an urban impacted coastal lagoon RESULTS: Bioturbator species richness had no overall significant effect on sediment [CH4] when comparisons of sediment [CH4] were made among species richness levels. However, bioturbator species richness significantly reduced sediment [CH4] when species richness levels were compared to the control (defaunated treatments, but this effect was significant only at the deepest sediment layer. Furthermore, bioturbator species composition had significant, but distinct effects on the patterns of reduction in sediment [CH4], depending on the sediment depth and the bioturbator species. CONCLUSIONS: We conclude that both the number and composition of bioturbator species are important to determine the effects of benthic bioturbators on spatial patterns of sediment [CH4], but the strength of these effects depend on species traits that determine interspecific interactions strength across the sediment vertical niche space.

  20. Contamination assessments of surface water in coastal lagoon (Maluan Bay, China) incorporating biomarker responses and bioaccumulation in hepatopancreas of exposed shrimp (Litopenaeus vannamei)--an integrative approach.

    Science.gov (United States)

    Wang, Zaosheng; Dong, Xiaoxia; Zhou, Shilei; Yan, Changzhou; Yan, Yijun; Chi, Qiaoqiao

    2014-01-01

    Maluan Bay, characterized by various degrees of anthropogenic contamination, is considered as one of the most industrialized and urbanized coastal lagoon in China, where large amounts of metal contaminants in surface water and biota were detected in previous studies. However, no clear discriminating power among sampling sites could be made only through comparisons between contaminant levels and Environmental Quality Standards and especially biological-based monitoring integrating biomarkers and bioaccumulation of exposure are scarce. For this purpose, antioxidants enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and glutathione-S-transferase were assessed using the hepatopancreas of shrimp Litopenaeus vannamei after 7 days laboratory exposure under controlled conditions to characterize the effects of polluted waters to shrimps. The metal concentrations of sampled water and bioaccumulation in hepatopancreatic tissues were also analyzed, and data were linked to biomarkers' responses by multivariate (principal component analysis-factor) analysis. A representation of estimated factor scores was performed to confirm the factor descriptions classifying the pollution status and characterizing the studied sites, which pointed out the impact of multiple sources of contaminants to the water quality and provided further evidences to the existence of clear pollution and toxicological gradients in critical areas. The results of the present investigation underlined that the integrated approach could be a powerful tool for the identification of causal toxic contaminants in complex mixtures and the assessment of human-induced environmental quality of the system in coastal zones.

  1. Whitemouth croaker, Micropogonias furnieri, trapped in a freshwater coastal lagoon: a natural comparison of freshwater and marine influences on otolith chemistry

    Directory of Open Access Journals (Sweden)

    Cristiano Q. de Albuquerque

    Full Text Available Strontium and barium incorporation into otoliths was compared between whitemouth croaker, Micropogonias furnieri, collected from an entrapped freshwater population (Mirim Lagoon and a normal marine/estuarine population in southern Brazil. Chemical analysis was performed using LA-ICPMS with the objective of validating the effects of marine and freshwater environments on Sr and Ba incorporation as a basis for further investigation of marine and freshwater connectivity of M. furnieri. The freshwater population was dominated by older fish with mean ±SD age of 34±1 y, whereas the coastal samples were dominated by younger fish of 14±7 y. Comparison of strontium and barium incorporation among otolith life-history profiles indicated significantly higher barium and lower strontium for the freshwater population compared to the marine population. Furthermore, comparison of otolith material deposited in the freshwater, estuarine and marine life-history phases demonstrated clear differences among these environments. Mean concentrations of strontium and barium in otoliths of M. furnieri were respectively 710 and 112 µg g-1 for freshwater, 2069 and 16.7 µg g-1 for estuarine, and 2990 and 2.7 µg g-1 for marine life-history phases. Barium concentrations in otoliths from the freshwater population of M. furnieri appeared high relative to other freshwater species. Strontium levels across life-history profiles of marine fish increased with age from 2000 to 2900 µg g-1, possibly indicating more time spent in marine than estuarine waters with age. In contrast, for the freshwater population, strontium levels decreased during the first year of life approximately to 700 µg g-1, and remained low and stable thereafter, consistent with the early life-history occurring in an estuarine environment prior to entrapment in Mirim Lagoon. The results confirm the strong and opposite effects of marine and freshwater environments on incorporation of barium and strontium into

  2. Impact assessment of agricultural inputs into a Mediterranean coastal lagoon (Mar Menor, SE Spain) on transplanted clams (Ruditapes decussatus) by biochemical and physiological responses.

    Science.gov (United States)

    Campillo, Juan A; Albentosa, Marina; Valdés, N Juliana; Moreno-González, Rubén; León, Víctor M

    2013-10-15

    The Mar Menor is a coastal lagoon threatened by the development of intensive agriculture in the surrounding areas. Large amounts of pesticides from these areas are discharged into El Albujón, a permanent watercourse flowing into the lagoon. We have used a multi-biomarker approach to assess the biological effects of agricultural pollution on a bivalve species. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AChE), oxidative stress (catalase, CAT; glutathione reductase, GR and lipid peroxidation, LPO), phase II biotransformation of xenobiotics (glutathione S-transferase, GST) and physiological stress (scope for growth, SFG) were measured in clams transplanted to four sites of the lagoon (two reference sites and two sites affected by the dispersion of the effluent of the El Albujón), for exposure periods of 7 and 22 days. The hazards of this effluent were also examined by simultaneously measuring up to 83 contaminants (pesticides, PCBs, PAHs and others) in samples of fresh water from the watercourse mouth and seawater from the deployed sites, as well as the bioaccumulation of organochlorinated compounds and PAHs in the transplanted animals. Biomarker responses showed marked differences between reference and affected sites after 7 and 22 days. However it was only after 22 days that principal component analysis (PCA) of the biomarker responses distinguished between clams deployed in sites affected by the dispersion of the effluent of the watercourse and those from the reference sites. The chemical analysis of water showed high concentrations of pesticides close to El Albujón watercourse mouth, with the greatest input flux corresponding to the organophosphate chlorpyrifos, followed by pendimethalin and naphthalene, and at lower levels acenaphthene, terbuthylazine-desethyl and chlorpyrifos-methyl. In this regard, PCA analysis showed that the biological effects of the mixture of pesticides in caged clams after 22 days were reduced levels of AchE and SFG

  3. Multi-scale functional and taxonomic β-diversity of the macroinvertebrate communities in a Mediterranean coastal lagoon

    Directory of Open Access Journals (Sweden)

    D. CABANA

    2017-03-01

    Full Text Available Benthic macroinvertebrate communities form the basis of the intricate lagoonal food web. Understanding their functional and taxonomic response, from a β-diversity perspective, is essential to disclose underlying patterns with potential applicability in conservation and management actions. Within the central lagoon of Messolonghi we studied the main environmental components structuring the macroinvertebrate community. We analyzed the β-taxonomic and β-functional diversity across the main habitats and seasons, over a year time frame. Our results outline habitat type and vegetation biomass as the major factors structuring the communities. We found environmental variability to have a positive correlation with functional β-diversity, however no correlation was found with taxonomic β-diversity. Across the seasons an asynchronous response of the functional and taxonomic β-diversity was identified. The taxonomic composition displayed significant heterogeneity during the driest period and the functional during the rainy season. Across the habitats the unvegetated presented higher taxonomic homogeneity and functionally heterogeneity, contrary the vegetated habitats present higher taxonomic variability and functional homogeneity. Across the seasons and habitats a pattern of functional redundancy and taxonomic replacement was identified. Besides high functional turnover versus low taxonomic turnover was documented in an anthropogenic organically enriched habitat We conclude that habitats display independent functional and taxonomic seasonal patterns, thus different processes may contribute to their variability. The framework presented here highlights the importance of studying both β-diversity components framed in a multiscale approach to better understand ecological processes and variability patterns. These results are important to understand macroinvertebrate community assembly processes and are valuable for conservation purposes.

  4. Ekologi Trofik Komunitas Ikan di Perairan Segara Menyan, Subang, Jawa Barat (Trophic Ecology of the Fish Community in Segara Menyan Coastal Lagoon, Subang, West Java

    Directory of Open Access Journals (Sweden)

    Ahmad Zahid

    2015-09-01

    Full Text Available Pengetahuan mengenai ekologi trofik merupakan dasar dalam memahami ekosistem secara keseluruhan yang dapat dijelaskan melalui pola hubungan trofik interspesies ataupun interserikat. Penelitian bertujuan untuk menjelaskan ekologi trofik meliputi indeks trofik dan jenis makanan dominan, serikat dan tingkat trofik, dan variasi spasial dan temporal komunitas ikan di estuari Segara Menyan. Pengambilan ikan contoh dilakukan setiap bulan pada zona berbeda. Ikan contoh dipisahkan berdasarkan waktu dan lokasi pengamatan, dianalisis isi saluran pencernaannya. Analisa data meliputi indeks vakuitas, jumlah total organisme makanan, jenis makanan dominan, luas relung makanan, dan tingkat trofik.  Pada pengamatan 106 spesies ikan, sebanyak 1-380 saluran pencernaan ikan diamati. Sebanyak lima dari 106 spesies memiliki nilai indeks vakuitas “0” dan jumlah makanan yang dikonsumsi bervariasi mulai dari empat hingga 27 jenis makanan. Secara umum, luas relung ikan adalah rendah berkisar 0,20-0,78 dan kebanyakan berada pada kisaran 0,20-0,48. Zooplankton merupakan jenis makanan paling dominan dikonsumsi oleh ikan. Komunitas ikan dikelompokkan dalam tujuh serikat trofik, yaitu detritivora, fitoplanktivora, zooplanktivora, zoobentivora, moluskivora, krustasivora, dan pisivora. Tingkat trofik komunitas ikan berkisar 2,05-4,73. Faktor perubahan ontogenetik, persediaan makanan, karakteristik habitat, dan ruaya beberapa spesies ikan memengaruhi variasi spasio-temporal jejaring makanan di Segara Menyan. Kata kunci: interaksi trofik, laguna, ikan, variasi spasio-temporal, serikat trofik Knowledge of trophic ecology is one way to understanding the whole ecosystem which explained by trophic relationship pattern (interspecies or interguild. The objective research was described of the trophic ecology, i.e. trophic index and dominant prey, trophic guild and trophic level, and spatio-temporal variation of fish community in Segara Menyan coastal lagoon. Fish were collected

  5. Combining L- and X-Band SAR Interferometry to Assess Ground Displacements in Heterogeneous Coastal Environments: The Po River Delta and Venice Lagoon, Italy

    Directory of Open Access Journals (Sweden)

    Luigi Tosi

    2016-04-01

    Full Text Available From leveling to SAR-based interferometry, the monitoring of land subsidence in coastal transitional environments significantly improved. However, the simultaneous assessment of the ground movements in these peculiar environments is still challenging. This is due to the presence of relatively small built-up zones and infrastructures, e.g., coastal infrastructures, bridges, and river embankments, within large natural or rural lands, e.g., river deltas, lagoons, and farmland. In this paper we present a multi-band SAR methodology to integrate COSMO-SkyMed and ALOS-PALSAR images. The method consists of a proper combination of the very high-resolution X-band Persistent Scatterer Interferometry (PSI, which achieves high-density and precise measurements on single structures and constructed areas, with L-band Short-Baseline SAR Interferometry (SBAS, properly implemented to raise its effectiveness in retrieving information in vegetated and wet zones. The combined methodology is applied on the Po River Delta and Venice coastland, Northern Italy, using 16 ALOS-PALSAR and 31 COSMO-SkyMed images covering the period between 2007 and 2011. After a proper calibration of the single PSI and SBAS solution using available GPS records, the datasets have been combined at both the regional and local scales. The measured displacements range from ~0 mm/yr down to −35 mm/yr. The results reveal the variable pattern of the subsidence characterizing the more natural and rural environments without losing the accuracy in quantifying the sinking of urban areas and infrastructures. Moreover, they allow improving the interpretation of the natural and anthropogenic processes responsible for the ongoing subsidence.

  6. Macroalgae blooms and delta 15N in subtropical coastal lagoons from the Southeastern Gulf of California: discrimination among agricultural, shrimp farm and sewage effluents.

    Science.gov (United States)

    Piñón-Gimate, Alejandra; Soto-Jiménez, Martín F; Ochoa-Izaguirre, María Julia; García-Pagés, Eynar; Páez-Osuna, Federico

    2009-08-01

    Macroalgae blooms of Gracilaria vermiculophylla, Hypnea spinella and Spyridia filamentosa have been found in coastal lagoons in the SE Gulf of California. Agriculture, livestock, shrimp and poultry farms and sewage contribute anthropogenic nitrogen to the systems. The delta(15)N of these sources, water column and macroalgae were studied in order to identify the N supply for macroalgae blooms. delta(15)N of three species of macroalgae (4.3-13.6 per thousand) were enriched compared to the water column (delta(15)N-NO(3)(-) 3.7-6.8 per thousand), probably because of fractioning from the macroalgae. delta(15)N of POM (1.4-10.3 per thousand) was similar to the water column but the relationship was unclear. Depending on the site, macroalgae showed different delta(15)N values since some sites receive more or less influence from one given source of the associated watershed, which is reflected in the different delta(15)N values of the macroalgae of the same system and in the relative contributions of the sources.

  7. Temporal variation of Mexiconema cichlasomae (Nematoda: Daniconematidae) in the Mayan cichlid fish Cichlasoma urophthalmus and its intermediate host Argulus yucatanus from a tropical coastal lagoon.

    Science.gov (United States)

    May-Tec, A L; Pech, D; Aguirre-Macedo, M L; Lewis, J W; Vidal-Martínez, V M

    2013-03-01

    The aim of the present investigation was to determine whether temporal variation in environmental factors such as rainfall or temperature influence long-term fluctuations in the prevalence and mean abundance of the nematode Mexiconema cichlasomae in the cichlid fish Cichlasoma uropthalmus and its crustacean intermediate host, Argulus yucatanus. The study was undertaken in a tropical coastal lagoon in the Yucatan Peninsula (south-eastern Mexico) over an 8-year period. Variations in temperature, rainfall and monthly infection levels for both hosts were analysed using time series and cross-correlations to detect possible recurrent patterns. Infections of M. cichlasomae in A. yucatanus showed annual peaks, while in C. urophthalmus peaks were bi-annual. The latter appear to be related to the accumulation of several generations of this nematode in C. urophthalmus. Rainfall and temperature appear to be key environmental factors in influencing temporal variation in the infection of M. cichlasomae over periods longer than a year together with the accumulation of larval stages throughout time.

  8. Comparative analysis of diet composition and its relation to morphological characteristics in juvenile fish of three lutjanid species in a Mexican Pacific coastal lagoon

    Directory of Open Access Journals (Sweden)

    Consuelo M. Aguilar-Betancourt

    2017-12-01

    Full Text Available ABSTRACT The main goal of this research was to investigate the differences in diet composition among three species of the genus Lutjanus inhabiting a coastal lagoon as juveniles. The working hypothesis was that these species feed on a common base of food resources and therefore, some niche overlap is present in terms of general diet composition. However, changes in the trophic niche with size and differences in some morphological traits among species explain observed differences in diet. Fish were collected during 42 sampling trips conducted regularly from February 2011 to January 2012 using several types of fishing gear. Total number of analyzed stomachs was 288 for Lutjanus argentiventris from 2.3 to 19.9 cm total length (TL; 178 for Lutjanus colorado ranging from 2.4 to 30.1 cm TL; and 183 for Lutjanus novemfasciatus with 1.2 to 20.0 cm TL. Results indicate that juveniles of all three lutjanid species share a general diet based on decapods and fishes. However, L. novemfasciatus has a more piscivorous habit, which can be explained by a more slender body shape and larger teeth, characteristics, which increase fish catching performance. Larger fish of all three species eat larger prey, which is consistent with the optimum foraging theory.

  9. Strong Acid Mixture and Sequential Geochemical Arsenic Extractions in Surface Sediments from the Santa Maria La Reforma Coastal Lagoon, Mexico: A Bioavailability Assessment.

    Science.gov (United States)

    Rivera-Hernández, José R; Green-Ruiz, Carlos

    2016-02-01

    Thirty-three sediment samples were collected from the Santa Maria La Reforma coastal lagoon and digested by way of a strong acid mixture and sequential arsenic (As)-extraction method to determine the arsenic (As) content and bioavailability. The As content was determined by atomic fluorescence spectrometry. In addition, grain-size analyses were performed, and organic carbon, carbonate, and iron (Fe) and manganese (Mn) concentrations were determined. Fe and Mn determination was performed by atomic absorption spectroscopy. A Pearson correlation matrix and As enrichment factors were calculated. Sediment concentrations from Santa Maria La Reforma ranged from 3.6 to 25 µg As g(-1) with an average of 13.4 ± 7.6 µg As g(-1). The highest values were observed in the northern (Playa Colorada), north-central (Mocorito River discharge zone), and southern zones ("El Tule" agricultural drain). Most samples were classified as exhibiting no or minor As enrichment and were lower than the threshold effect level (TEL; 7.24 µg g(-1)) for biota (MacDonald et al. in Ecotoxicology 5:253-278, 1996). Low bioavailable As values (<3 %) were measured in the majority of the sediment. The highest As percentages were associated with the oxyhydroxide fraction (F5). The results indicate that As bioavailability is negligible.

  10. Fast shoreline erosion induced by ship wakes in a coastal lagoon: Field evidence and remote sensing analysis

    Science.gov (United States)

    Lorenzetti, Giuliano; Manfé, Giorgia; Scarpa, Gian Marco; Molinaroli, Emanuela; Parnell, Kevin Ellis; Rapaglia, John Paul; Gionta, Maria; Soomere, Tarmo

    2017-01-01

    An investigation based on in-situ surveys combined with remote sensing and GIS analysis revealed fast shoreline retreat on the side of a major waterway, the Malamocco Marghera Channel, in the Lagoon of Venice, Italy. Monthly and long-term regression rates caused by ship wakes in a reclaimed industrial area were considered. The short-term analysis, based on field surveys carried out between April 2014 and January 2015, revealed that the speed of shoreline regression was insignificantly dependent on the distance from the navigation channel, but was not constant through time. Periods of high water levels due to tidal forcing or storm surges, more common in the winter season, are characterized by faster regression rates. The retreat is a discontinuous process in time and space depending on the morpho-stratigraphy and the vegetation cover of the artificial deposits. A GIS analysis performed with the available imagery shows an average retreat of 3˗4 m/yr in the period between 1974 and 2015. Digitization of historical maps and bathymetric surveys made in April 2015 enabled the construction of two digital terrain models for both past and present situations. The two models have been used to calculate the total volume of sediment lost during the period 1968˗2015 (1.19×106 m3). The results show that in the presence of heavy ship traffic, ship-channel interactions can dominate the morphodynamics of a waterway and its margins. The analysis enables a better understanding of how shallow-water systems react to the human activities in the post-industrial period. An adequate evaluation of the temporal and spatial variation of shoreline position is also crucial for the development of future scenarios and for the sustainable management port traffic worldwide. PMID:29088244

  11. Short Term CO2 Enrichment Increases Carbon Sequestration of Air-Exposed Intertidal Communities of a Coastal Lagoon

    Directory of Open Access Journals (Sweden)

    Amrit K. Mishra

    2018-01-01

    Full Text Available In situ production responses of air-exposed intertidal communities under CO2 enrichment are reported here for the first time. We assessed the short-term effects of CO2 on the light responses of the net community production (NCP and community respiration (CR of intertidal Z. noltei and unvegetated sediment communities of Ria Formosa lagoon, when exposed to air. NCP and CR were measured in situ in summer and winter, under present and CO2 enriched conditions using benthic chambers. Within chamber CO2 evolution measurements were carried out by a series of short-term incubations (30 min using an infra-red gas analyser. Liner regression models fitted to the NCP-irradiance responses were used to estimate the seasonal budgets of air-exposed, intertidal production as determined by the daily and seasonal variation of incident photosynthetic active radiation. High CO2 resulted in higher CO2 sequestration by both communities in both summer and winter seasons. Lower respiration rates of both communities under high CO2 further contributed to a potential negative climate feedback, except in winter when the CR of sediment community was higher. The light compensation points (LCP (light intensity where production equals respiration of Z. noltei and sediment communities also decreased under CO2 enriched conditions in both seasons. The seasonal community production of Z. noltei was 115.54 ± 7.58 g C m−2 season−1 in summer and 29.45 ± 4.04 g C m−2 season−1 in winter and of unvegetated sediment was 91.28 ± 6.32 g C m−2 season−1 in summer and 25.83 ± 4.01 g C m−2 season−1 in winter under CO2 enriched conditions. Future CO2 conditions may increase air-exposed seagrass production by about 1.5-fold and unvegetated sediments by about 1.2-fold.

  12. Fast shoreline erosion induced by ship wakes in a coastal lagoon: Field evidence and remote sensing analysis.

    Science.gov (United States)

    Zaggia, Luca; Lorenzetti, Giuliano; Manfé, Giorgia; Scarpa, Gian Marco; Molinaroli, Emanuela; Parnell, Kevin Ellis; Rapaglia, John Paul; Gionta, Maria; Soomere, Tarmo

    2017-01-01

    An investigation based on in-situ surveys combined with remote sensing and GIS analysis revealed fast shoreline retreat on the side of a major waterway, the Malamocco Marghera Channel, in the Lagoon of Venice, Italy. Monthly and long-term regression rates caused by ship wakes in a reclaimed industrial area were considered. The short-term analysis, based on field surveys carried out between April 2014 and January 2015, revealed that the speed of shoreline regression was insignificantly dependent on the distance from the navigation channel, but was not constant through time. Periods of high water levels due to tidal forcing or storm surges, more common in the winter season, are characterized by faster regression rates. The retreat is a discontinuous process in time and space depending on the morpho-stratigraphy and the vegetation cover of the artificial deposits. A GIS analysis performed with the available imagery shows an average retreat of 3-4 m/yr in the period between 1974 and 2015. Digitization of historical maps and bathymetric surveys made in April 2015 enabled the construction of two digital terrain models for both past and present situations. The two models have been used to calculate the total volume of sediment lost during the period 1968-2015 (1.19×106 m3). The results show that in the presence of heavy ship traffic, ship-channel interactions can dominate the morphodynamics of a waterway and its margins. The analysis enables a better understanding of how shallow-water systems react to the human activities in the post-industrial period. An adequate evaluation of the temporal and spatial variation of shoreline position is also crucial for the development of future scenarios and for the sustainable management port traffic worldwide.

  13. Fast shoreline erosion induced by ship wakes in a coastal lagoon: Field evidence and remote sensing analysis.

    Directory of Open Access Journals (Sweden)

    Luca Zaggia

    Full Text Available An investigation based on in-situ surveys combined with remote sensing and GIS analysis revealed fast shoreline retreat on the side of a major waterway, the Malamocco Marghera Channel, in the Lagoon of Venice, Italy. Monthly and long-term regression rates caused by ship wakes in a reclaimed industrial area were considered. The short-term analysis, based on field surveys carried out between April 2014 and January 2015, revealed that the speed of shoreline regression was insignificantly dependent on the distance from the navigation channel, but was not constant through time. Periods of high water levels due to tidal forcing or storm surges, more common in the winter season, are characterized by faster regression rates. The retreat is a discontinuous process in time and space depending on the morpho-stratigraphy and the vegetation cover of the artificial deposits. A GIS analysis performed with the available imagery shows an average retreat of 3-4 m/yr in the period between 1974 and 2015. Digitization of historical maps and bathymetric surveys made in April 2015 enabled the construction of two digital terrain models for both past and present situations. The two models have been used to calculate the total volume of sediment lost during the period 1968-2015 (1.19×106 m3. The results show that in the presence of heavy ship traffic, ship-channel interactions can dominate the morphodynamics of a waterway and its margins. The analysis enables a better understanding of how shallow-water systems react to the human activities in the post-industrial period. An adequate evaluation of the temporal and spatial variation of shoreline position is also crucial for the development of future scenarios and for the sustainable management port traffic worldwide.

  14. Coastal lagoon sediments as a recorder of Holocene landscape evolution and sea-level development: Samsø, southern Kattegat Sea, Denmark

    DEFF Research Database (Denmark)

    Sander, Lasse; Fruergaard, Mikkel; Johannessen, Peter N.

    and spatial reconstruction of paleo-shoreline positions. Further, a number of 31 cores were retrieved from modern and relict lagoons on the island. Stratigraphy, grain-size distribution, fossil and organic matter content were analyzed and compared. X-ray fluorescence core scanning was further employed...... on the fine-grained (lagoonal) sections of the cores. Age control was facilitated using radiocarbon and optically stimulated luminescence dating. Our data produced a surprisingly consistent pattern for the sedimentary successions found in the lagoons. The initial transgression can be identified along...... with the onset of deposition of fine-grained, organic-rich lagoonal sediments. The subsequent truncation and partial erosion of the lagoon sediments can be related to a decreasing sea-level. Based on these findings, we suggest a conceptual model that allows inferring age and elevation of transgressive...

  15. Growth, mortality and migratory pattern of white shrimp (Litopenaeus vannamei, Crustacea, Penaeidae in the Carretas-Pereyra coastal lagoon system, Mexico

    Directory of Open Access Journals (Sweden)

    G Rivera-Velázquez

    2008-06-01

    Full Text Available The growth, mortality and migration pattern of the population of Litopenaeus vannamei Boone 1931 in the Carretas-Pereyra coastal lagoon system, Mexico, were studied. The shrimp spatial distribution and abundance were analyzed in relation to salinity, water temperature, and substrate. A total of 2 669 shrimps was collected at 22 sites sampled monthly from March 2004 to August 2005. Juvenile shrimps of L. vannamei were present in the coastal lagoon system throughout the year, reaching densities from 0.001 to 0.302 ind/m². The estimated daily growth rate was 0.06 to 0.27 mm carapace length (CL. No significant seasonal differences were appreciated. Weekly total mortality (Z was between 0.04 and 0.34. Recruits, juveniles and sub-adults displayed a bimodal distributional pattern regulated by the prevailing conditions during the dry season. The peak abundance of juvenile stages occurred in December-January and March-May. The abundance presented an inverse correlation with salinity (r=-0.42; pSe estudió el crecimiento, la mortalidad y el patrón de migración del camarón Litopenaeus vannamei Boone 1931 en el sistema lagunar costero Carretas Pereyra, México. La distribución espacial y la abundancia fueron analizadas con relación a la salinidad, temperatura y substrato. De marzo de 2004 a agosto de 2005 se recolectó un total de 2669 camarones con un muestreo mensual en 22 sitios. Los jóvenes se hallaron todo el año en el sistema lagunar costero, con densidades entre 0.001 y 0.302 ind/m². La tasa de crecimiento diaria fue de 0.06 a 0.27 mm longitud del cefalotórax (CL y no se apreciaron diferencias significativas entre estaciones. La mortalidad total (Z semanal estuvo entre 0.04 y 0.34. Reclutas, jóvenes y subadultos presentan un patrón de distribución bimodal regulado por las condiciones prevalecientes durante la estación de estío. Los valores máximos de abundancia de los estadios juveniles se presentan en diciembre-enero y marzo-mayo. La

  16. Seasonal and inter-annual eutrophication dynamics in a hypereutrophic shallow coastal lagoon from ten years of satellite observations and in-situ data

    Science.gov (United States)

    Pitarch, Jaime; Ruiz-Verdú, Antonio; Soria, Juan M.; Santoleri, Rosalia

    2016-04-01

    The Albufera de Valencia (39.33 N, 0.37 W) is a hypereutrophic shallow coastal lagoon, having a near round shape of ~ 5 km diameter and ~ 1 m average depth. At the west side, the lake is separated from the sea by a narrow land strip, but three artificial channels allow connection to the sea, regulated by gates. The rest of the lake is surrounded by rice fields that were made by gaining surface from the lake around a century ago. Nowadays, the ecological state of the lake is very degraded. Freshwater inflow is insufficient and residence time is too high. Despite some improvements in waste water treatment, high loads of sediment-stored nutrients are often resuspended due to habitual strong winds and made available for primary production. The previously abundant bottom vegetation disappeared decades ago and secchi depth does not reach more than few tens of centimeters. The lake suffers from cyanobacterial blooms and massive fish deaths. Despite its vital importance as a coastal wetland in the western Mediterranean region, its water quality is not routinely monitored, so its seasonality and eventual blooming events have not been sistematically studied. In this study, we aim at filling this gap using satellite data. Medium-resolution satellite-borne sensors constitute an appropriate tool for this sake due to the lake's medium size and little cloud cover time over the region. In particular, the European MERIS sensor (2002-2012) is specially well suited due to its unique spectral bands configuration for cyanobacterial detection. Apart from the utility of the results themselves, study of this sensor provides a strong baseline for operational utilization of its successor, the new-coming European Sentinel 3-OLCI sensor. We have processed the full archived MERIS archived data. By adequate choice of band ratios and posterior calibration to in-situ samples, the time series of chlorophyll concentration is derived. Derived seasonality reveals a pattern that is determined by the

  17. Bioaccumulation and biomagnification of mercury and methylmercury in four sympatric coastal sharks in a protected subtropical lagoon.

    Science.gov (United States)

    Matulik, Adam G; Kerstetter, David W; Hammerschlag, Neil; Divoll, Timothy; Hammerschmidt, Chad R; Evers, David C

    2017-03-15

    Mercury bioaccumulation is frequently observed in marine ecosystems, often with stronger effects at higher trophic levels. We compared total mercury (THg) and methylmercury (MeHg) from muscle with length, comparative isotopic niche, and diet (via δ 13 C and δ 15 N) among four sympatric coastal sharks in Florida Bay (USA): blacknose, blacktip, bull, and lemon. Mercury in blacknose and blacktip sharks increased significantly with size, whereas bull and lemon sharks had a high variance in mercury relative to size. Both δ 13 C and δ 15 N were consistent with general resource use and trophic position relationships across all species. A significant relationship was observed between δ 13 C and mercury in blacktip sharks, suggesting an ontogenetic shift isotopic niche, possibly a dietary change. Multiple regression showed that δ 13 C and δ 15 N were the strongest factors regarding mercury bioaccumulation in individuals across all species. Additional research is recommended to resolve the mechanisms that determine mercury biomagnification in individual shark species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Nonlinear hydrodynamics in a Mediterranean lagoon

    Directory of Open Access Journals (Sweden)

    E. Alekseenko

    2013-03-01

    Full Text Available The paper addresses the application of the nonlinear hydrodynamics model (RANS (Reynolds-averaged Navier–Stokes equations in a wide semi-enclosed Mediterranean lagoon (Berre lagoon, considering three natural forcing functions, i.e., sea tide propagating through a long narrow channel, wind and runoff. Main attention is focused to characteristic velocities (at free surface and bottom and to free surface elevation associated to each of these three mechanisms, with special attention to the nearshore areas (i.e., in shallow water. The most interesting result concerns wind effects which, due to Berre lagoon bathymetry, give rise to downwind coastal jets, alongshore, in shallow water areas. Such coastal jets were never mentioned before in Berre lagoon literature.

  19. Assessing the impact of dairy waste lagoons on groundwater quality using a spatial analysis of vadose zone and groundwater information in a coastal phreatic aquifer.

    Science.gov (United States)

    Baram, S; Kurtzman, D; Ronen, Z; Peeters, A; Dahan, O

    2014-01-01

    Dairy waste lagoons are considered to be point sources of groundwater contamination by chloride (Cl(-)), different nitrogen-species and pathogens/microorganisms. The objective of this work is to introduce a methodology to assess the past and future impacts of such lagoons on regional groundwater quality. The method is based on a spatial statistical analysis of Cl(-) and total nitrogen (TN) concentration distributions in the saturated and the vadose (unsaturated) zones. The method provides quantitative data on the relation between the locations of dairy lagoons and the spatial variability in Cl(-) and TN concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that despite the small surface area covered by the dairy lagoons in this region (0.8%), leachates from lagoons have contributed 6.0% and 12.6% of the total mass of Cl(-) and TN (mainly as NO3(-)-N) added to the aquifer. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl(-) and TN to the groundwater. A low spatial correlation between the Cl(-) and NO3(-)-N concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy waste lagoon being a point source for groundwater contamination by Cl(-) and NO3(-)-N. Mass balance calculations, for the vadose zone of the entire region, indicated that drying of the lagoons would decrease the regional groundwater salinization process (11% of the total Cl(-) load is stored under lagoons). A more considerable reduction in the groundwater contamination by NO3(-)-N is expected (25% of the NO3(-)-N load is stored under lagoons). Results

  20. Study on zooplankton distributions in Mahin Lagoon within ...

    African Journals Online (AJOL)

    Distributions of zooplankton were studied in Mahin Lagoon within the transgressive mud coastal zone, Southwest Nigeria. Zooplankton samples were collected at fifteen stations along the stretch of the lagoon and analysed using standard methods for four months (October 2013, 2014, March 2014 and 2015). In each of the ...

  1. Factors responsible for rapid dissipation of acidic herbicides in the coastal lagoons of the Camargue (Rhône River Delta, France).

    Science.gov (United States)

    Al Housari, Fadi; Höhener, Patrick; Chiron, Serge

    2011-01-01

    This study was aimed at investigating which processes cause acidic herbicides (e.g., bentazone, MCPA and dichlorprop) to rapidly disappear in the lagoons of the Rhône delta, which are peculiar brackish and shallow aquatic environments. The use of the model MASAS (Modeling of Anthropogenic Substances in Aquatic Systems) revealed that sorption, sedimentation, volatilization, flushing and abiotic hydrolysis had a minor role in the attenuation of the investigated herbicides. Laboratory scale biodegradation and photodegradation studies were conducted to better assess the significance of these two processes in the natural attenuation of herbicides in brackish (lagoons) waters with respect to fresh waters (canals draining paddy fields). Herbicide biodegradation rates were significantly lower in lagoon water than in canal water. Consequently, photodegradation was the main dissipation route of all investigated herbicides. The contribution of indirect photolysis was relevant for MCPA and dichlorprop while direct photolysis dominated for bentazone removal. There is a need to further investigate the identity of phototransformation products of herbicides in lagoons. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. How is shrimp aquaculture transforming coastal livelihoods and lagoons in Estero Real, Nicaragua? The need to integrate social-ecological research and ecosystem-based approaches.

    Science.gov (United States)

    Benessaiah, Karina; Sengupta, Raja

    2014-08-01

    Ecosystem-based approaches to aquaculture integrate environmental concerns into planning. Social-ecological systems research can improve this approach by explicitly relating ecological and social dynamics of change at multiple scales. Doing so requires not only addressing direct effects of aquaculture but also considering indirect factors such as changes in livelihood strategies, governance dynamics, and power relations. We selected the community of Puerto Morazán, Nicaragua as a case study to demonstrate how the introduction of small-scale aquaculture radically transformed another key livelihood activity, lagoon shrimp fishing, and the effects that these changes have had on lagoons and the people that depend on them. We find that shrimp aquaculture played a key role in the collapse, in the 1990s, of an existing lagoon common-property management. Shrimp aquaculture-related capital enabled the adoption of a new fishing technique that not only degraded lagoons but also led to their gradual privatization. The existence of social ties between small-scale shrimp farmers and other community members mitigated the impacts of privatization, illustrating the importance of social capital. Since 2008, community members are seeking to communally manage the lagoons once again, in response to degraded environmental conditions and a consolidation of the shrimp industry at the expense of smaller actors. This research shows that shrimp aquaculture intersects with a complex set of drivers, affecting not only how ecosystems are managed but also how they are perceived and valued. Understanding these social-ecological dynamics is essential to implement realistic policies and management of mangrove ecosystems and address the needs of resource-dependent people.

  3. An assessment of fecal indicator and other bacteria from an urbanized coastal lagoon in the City of Los Angeles, California, USA.

    Science.gov (United States)

    Dorsey, John H; Carmona-Galindo, Víctor D; Leary, Christopher; Huh, Julie; Valdez, Jennifer

    2013-03-01

    A study was performed in Del Rey Lagoon, City of Los Angeles, to determine if the lagoon was as a source or sink for fecal indicator bacteria (FIB: total coliforms, Escherichia coli, enterococci) and to screen for the presence of other potentially pathogenic bacteria. The lagoon receives tidal flows from the adjacent Ballona Estuary whose water usually is contaminated with FIB originating from the highly urbanized Ballona Creek Watershed. During 16 sampling events from February 2008 through March 2009, replicate water samples (n = 3) were collected 1 h prior to the high tide and 1 h prior to the following low tide. FIB concentrations were measured by the defined substrate method (IDEXX, Westbrook, Me) followed by culturing of bacterial isolates sampled from positive IDEXX Quanti-Tray wells and were identified using the Vitek 2 Compact (bioMérieux, Durham, NC). Mean concentrations of FIB often differed by an order of magnitude from flood to ebb flow conditions. The lagoon tended to act as a sink for total coliforms based on the ratio of mean flood to ebb densities (R (F/E)) >1.0 during 56 % of the sampling events and during ebb flows, as a source for E. coli and enterococci (R (F/E) <1.69 % of events). Approximately 54 species were identified from 277 isolates cultured from the IDEXX Quanti-Trays. Of these, 54 % were species known to include pathogenic strains that can be naturally occurring, introduced in runoff, or originated from other sources. Diversity and cluster analyses indicated a dynamic assemblage that changes in species composition with day-to-day fluctuations as well as tidal action. The concept of monitoring the lagoon and estuary as a sentinel habitat for pathogenic assemblages is discussed.

  4. Socio-ecological risk factors for prime-age adult death in two coastal areas of Vietnam.

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    Deok Ryun Kim

    Full Text Available BACKGROUND: Hierarchical spatial models enable the geographic and ecological analysis of health data thereby providing useful information for designing effective health interventions. In this study, we used a Bayesian hierarchical spatial model to evaluate mortality data in Vietnam. The model enabled identification of socio-ecological risk factors and generation of risk maps to better understand the causes and geographic implications of prime-age (15 to less than 45 years adult death. METHODS AND FINDINGS: The study was conducted in two sites: Nha Trang and Hue in Vietnam. The study areas were split into 500×500 meter cells to define neighborhoods. We first extracted socio-demographic data from population databases of the two sites, and then aggregated the data by neighborhood. We used spatial hierarchical model that borrows strength from neighbors for evaluating risk factors and for creating spatially smoothed risk map after adjusting for neighborhood level covariates. The Markov chain Monte Carlo procedure was used to estimate the parameters. Male mortality was more than twice the female mortality. The rates also varied by age and sex. The most frequent cause of mortality was traffic accidents and drowning for men and traffic accidents and suicide for women. Lower education of household heads in the neighborhood was an important risk factor for increased mortality. The mortality was highly variable in space and the socio-ecological risk factors are sensitive to study site and sex. CONCLUSION: Our study suggests that lower education of the household head is an important predictor for prime age adult mortality. Variability in socio-ecological risk factors and in risk areas by sex make it challenging to design appropriate intervention strategies aimed at decreasing prime-age adult deaths in Vietnam.

  5. Effect of nitrogen and phosphorus supply on growth, chlorophyll content and tissue composition of the macroalga Chaetomorpha linum (O.F. Müll, Kütz, in a Mediterranean Coastal Lagoon

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    Margarita Menéndez

    2002-12-01

    Full Text Available The effect of dissolved nutrients on growth, nutrient content and uptake rates of Chaetomorpha linum in a Mediterranean coastal lagoon (Tancada, Ebro delta, NE Spain was studied in laboratory experiments. Water was enriched with distinct forms of nitrogen, such as nitrate or ammonium and phosphorus. Enrichment with N, P or with both nutrients resulted in a significant increase in the tissue content of these nutrients. N-enrichment was followed by an increase in chlorophyll content after 4 days of treatment, although the difference was only significant when nitrate was added without P. P-enrichment had no significant effect on chlorophyll content. In all the treatments an increase in biomass was obseved after 10 days. This increase was higher in the N+P treatments. In all the treatments the uptake rate was significantly higher when nutrients were added than in control jars. The uptake rate of N, as ammonium, and P were significantly higher when they were added alone while that of N as nitrate was higher in the N+P treatment. In the P-enriched cultures, the final P-content of macroalgal tissues was ten-fold that of the initial tissue concentrations, thereby indicating luxury P-uptake. Moreover, at the end of the incubation the N:P ratio increased to 80, showing that P rather than N was the limiting factor for C. linum in the Tancada lagoon. The relatively high availability of N is related to the N inputs from rice fields that surround the lagoon and to P binding in sediments.

  6. [Feeding habits of the fish Lagodon rhomboides (Perciformes: Sparidae) at the coastal lagoon of Chelem, Yucatán, México].

    Science.gov (United States)

    Canto-Maza, Walter Gabriel; Vega-Cendejas, María Eugenia

    2008-12-01

    Stomach contents of Lagodon rhomboides, the most abundant fish species from seagrass beds in Chelem Lagoon, Yucatan, Mexico, were analyzed. The specimens were collected using a beach seine at eight stations distributed randomly in the lagoon during July, September and November 2002. The trophic components were analyzed by means of the relative abundance (%A) and frequency of occurrence (FO) indices. The trophic similarity between different ontogenetic stages was determined using the Bray-Curtis Index. A total of 90 stomach contents were analyzed. This species is omnivorous, including vegetal and animal material and has a wide trophic spectrum with 58 alimentary items. Trophic ontogenetic variation was significant with a transition from one feeding stage to the next. Small individuals (4.0 -8.0 cm LE) preferentially consume plankton preys and microcrustaceans, while in bigger sizes, the macrocrustaceans, annelids and macrophytes were the main food.

  7. PCDD/F and PCB multi-media ambient concentrations, congener patterns and occurrence in a Mediterranean coastal lagoon (Etang de Thau, France)

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Jimenez, J. [European Commission-DG Joint Research Centre, Institute for Environment and Sustainability(IES), TP 290, Via Enrico Fermi, 1. 21020 Ispra (Vatican City State, Holy See,) (Italy)], E-mail: javier.castro-jimenez@jrc.it; Deviller, G.; Ghiani, M.; Loos, R.; Mariani, G.; Skejo, H.; Umlauf, G.; Wollgast, J. [European Commission-DG Joint Research Centre, Institute for Environment and Sustainability(IES), TP 290, Via Enrico Fermi, 1. 21020 Ispra (Vatican City State, Holy See,) (Italy); Laugier, T. [Ifremer, Laboratory of Environmental Resources, Bd Jean Monnet, BP 171, 34203 Sete Cedex (France); Heas-Moisan, K.; Leaute, F.; Munschy, C.; Tixier, C.; Tronczynski, J. [Ifremer, Laboratory of Biogeochemistry of Organic Contaminants, BP 21105, 44311 Nantes Cedex 3 (France)

    2008-11-15

    Ambient concentrations, congener patterns and multi-media distribution of PCDD/Fs and PCBs were determined in air, water, sediment and mussels in a semi-enclosed marine ecosystem (Thau lagoon, France). {sigma}2,3,7,8-PCDD/F and {sigma}7ICES PCB air concentrations (0.2-1.4 and 31-57 pg m{sup -3}, respectively) were typical of rural areas. Concentrations in the water column were very low for PCDD/Fs (163-476 fg L{sup -1}) and low for PCBs (138-708 pg L{sup -1}). PCDD/F and PCB concentrations found in surface sediment (0.15-1.6 and 2.5-33 ng g{sup -1} d.w., respectively) and mussel (13-21 pg g{sup -1} d.w. and 10-39 ng g{sup -1} d.w., respectively) were medium levels. PCDD/F congener patterns observed in air, water particulate phase and sediments were similar suggesting direct coupling among these compartments and atmospheric inputs of PCDD/Fs into the lagoon. Conversely, for the same set of samples, similar patterns were not observed for PCBs in the mentioned compartments. - Multi-media ambient concentrations and distribution of PCDD/Fs and PCBs in Thau Lagoon provide insight into the POPs behavior in semi-enclosed marine ecosystems.

  8. Using Shoreline Video Assessment for coastal planning and restoration in the context of climate change in Kien Giang, Vietnam

    Science.gov (United States)

    Van Cuong, Chu; Russell, Michael; Brown, Sharon; Dart, Peter

    2015-06-01

    Kien Giang, bordering Cambodia in the Mekong River Delta, is one of the two most vulnerable provinces in the region to coastal erosion and flooding. Coastal protection can conflict with current land use and economic development activities. The conditions of the mangrove forest and mainland coastline of the Kien Giang province were assessed using the Shoreline Video Assessment Method (SVAM) backed up with information from satellite images. Half of the 206 km Kien Giang coastline has been eroded or is being eroded. Protective mangrove forests naturally occurred in 74% of the coastline but have been under threat from illegal cutting, erosion and coastal retreat. Accurate information on the state of the coastline and mangrove forest health provided invaluable data for developing a new coastal rehabilitation plan to guard against future sea level rise. In contrast to the current boundary management of land and natural resources, this plan divided the provincial coastline into 19 sections based on the landscape condition and exposure to erosion. Priority strategic actions for erosion management, mangrove restoration and sustainable livelihood development for local communities for each section of coast were developed based on an integrated cross sectoral approach and practical experience in the Conservation and Development of the Kien Giang Biosphere Reserve Project.

  9. [Spatial-temporal variation of the macroinvertebrate epibiont community on red mangrove prop roots Rhizophora mangle (Rhizophoraceae) at La Mancha coastal lagoon, Veracruz, Mexico].

    Science.gov (United States)

    Ruiz, Marcela; López-Portillo, Jorge

    2014-12-01

    La Mancha lagoon is connected to the Gulf of Mexico through an estuarine ephemeral inlet, a sand bar, which opens during the rainy season and closes during the late fall and the winter storm season. As the lagoon fills up with the permanent stream flow into its Southern part, the water level increases and the sand bar opens up, releasing huge volumes of water into the ocean and leaving the previously flooded intertidal zone exposed to drying. In this study, we described the spatial and temporal variations of structure and composition of the community living on the surface of red mangrove prop roots, related to the hydrodynamic of the estuarine inlet. Four red mangrove prop roots were collected every three months, over an annual period, at ten sampling stations. Water temperature, salinity, dissolved oxygen, water depth and transparency were also measured at each sampling event. To describe the identity, abundance, biomass, and specific richness of epibiont coverage on the prop roots, measurements were taken at 10 cm intervals (herein called "horizons"). A total of 59,632 specimens and a total biomass of 172 g/cm2 were registered, and a maximum of eleven horizons presented at least one" species of epibionts. Two species of polychaetes, 12 of mollusks and 14 of crustaceans were identified, with Mytilopsis leucophaeata as the most abundant, Ficopomatus miamiensis as the most common and Crassostrea rhizophorae with the highest contribution in biomass. Sampling effort was assessed using species accumulation curves, resulting that the efficiency was, in general, greater than 90% of the richness predicted by asymptotic models. The hydrodynamics of the estuarine inlet had a great influence on the environmental conditions of the lagoon and on the spatial and temporal variation of the epibiont community: (a) when the inlet is open, there is a North-South gradient in environmental parameters (b) when the inlet is closed and the water level increases, the epibionts especially

  10. Climate Change and Vietnam

    Science.gov (United States)

    2013-11-01

    projects (the majority of them in South and South East Asia); focusing in Vietnam on climate change planning and carbon sequestration markets . 33...enhancement for dairy cattle. 21 In the parallel line of effort, MNRE’s priorities for adaptation programs are agriculture, forestry, coastal zone management...Climate change assistance,” AusAID, 13 June 2013, accessed 15 October 2013, http://www.ausaid.gov.au. 33 IFAD, “ Planning for Climate Change in

  11. Relative importance of water column vs zooplankton variables in the determination of late-stage larval fish assemblage structure in coastal waters of a coral reef lagoon

    Directory of Open Access Journals (Sweden)

    Laure Carassou

    2009-10-01

    Full Text Available The relationship between fish larvae and their zooplanktonic prey has not been fully explored for late-stage larvae of coral-reef fish in lagoonal environments. However, compared to most temperate taxa, these larvae are characterized by strong sensory and swimming abilities, which may influence their feeding behaviour in the water column. The present study aims to determine the relative importance of the water column and zooplankton variables for the structure of pre-settlement larval fish assemblages within a single season in three bays of the coral reef lagoon of New Caledonia, southwest Pacific. The structure of larval assemblages was found to be explained better by water column variables in two out of the three bays examined. Zooplankton variables only played a role in one bay out of the three, probably due to the lower variability in the water column variables. Moreover, the relationship between total larval fish abundance and zooplankton density was not significant in any of the three bays. These results suggest that the relationship between late-stage coral-reef fish larvae and their prey: 1 is difficult to detect at small spatial and temporal scales, 2 is probably complex and non-linear, 3 depends on environmental conditions, and 4 probably varies between fish taxa.

  12. Variation of a benthic heterotrophic bacteria community with different respiratory metabolisms in Coyuca de Benítez coastal lagoon (Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    María Jesús Ferrara-Guerrero

    2007-03-01

    Full Text Available The fluctuations of the number, biomass and composition of the heterotrophic community were studied daily for two days, according to depth, pH, Eh, O2 and organic carbon concentration within a zone of the canal between the Coyuca de Benítez lagoon (Guerrero, Mexico and the coastal waters. At the three moments of the day studied (6 am, 2 pm and 10 pm, the oxygen concentrations in the overlying water and in the superficial sediment layer were near air-saturation in the diurnal samplings (582 µM at 6 am and 665 µM at 2 pm, and sub-satured during the night (158 µM. In the sediments, the models of vertical distribution of Eh and organic carbon distributions were very irregular due to the bio-perturbation of the benthic, meio- and macrofauna, whose activity allows the superficial organic carbon to migrate towards sediment deeper layers. Vertical distribution of the different viable bacteria populations seems to be related to the hydrodynamic patterns of the communicating canal and sediments heterogeneity. In the sediment column, the heterotrophic bacteria total number varied from 6.8 to 20.3 x 108 cells cm-3. The highest heterotrophic bacterial biomass values were encountered during the diurnal samplings (39.2 µgC.l-1 at 6 am and 34.4 µgC.l-1 at 2 pm and the lowest during the night (9.7 µgC.l-1. The fluctuations of viable heterotrophic bacteria populations with different respiratory metabolisms (aerobic, microaerophilic and anaerobic can be explained by the existence of suboxic microniches that appear when particles of sediment are resuspended due to the water circulation and the benthic infauna excavating activity, that allows the supernatant water oxygen to penetrate through its galleries towards deeper sediment zones. The statistical analysis (Multiple lineal regression model r²≥ 0.5 showed that the on the whole, the hydrological parameters are not influence over the bacterial number and bacterial biomass distribution (r²≤ 0

  13. Asymmetric progradation of a coastal mangrove forest controlled by combined fluvial and marine influence, Cù Lao Dung, Vietnam

    Science.gov (United States)

    Fricke, A. T.; Nittrouer, C. A.; Ogston, A. S.; Vo-Luong, H. P.

    2017-09-01

    Mangrove forests are an important means of coastal protection along many shorelines in the tropics, and are often associated with large rivers there. Isolating the contribution of any one factor to the progradation or retreat of a coastal mangrove forest is often hindered by the physical separation between sites that are subject to vastly different combinations of marine and fluvial influence. The mangrove forest at the seaward end of Cù Lao Dung, an island in the Mekong Delta, includes areas with progradation rates of 10 s m y-1, and areas that have experienced little to no progradation in recent decades. The physical proximity (<12 km) of these two environments allows detailed hydrodynamic and sediment-dynamic measurements to be related directly to morphologic change and century-scale stratigraphy. Contrary to conventional understanding, the region of mangrove forest prograding most rapidly is subject to the greatest wave attack, while progradation is slowest in the most quiescent area. Limited progradation here is the product of a reduction in the supply of sediment to certain parts of the mangrove forest due to nearby estuarine dynamics operating on spring-neap timescales. Measurements of sediment flux show net transport into the rapidly prograding part of the forest, and transport out from the part of the forest with minimal progradation. Century-scale rates of sediment accumulation determined using 210Pb geochronology are consistent with in-situ dynamical measurements and geomorphic evolution of the mangrove forest. Where progradation is most rapid, sediment accumulation rates (3.0-5.1 cm y-1) exceed the rate of local sea-level rise (∼1.5 cm y-1). In contrast, sediment-accumulation rates in the area of minimal progradation (0.8-2.8 cm y-1) only somewhat exceed the rate of local sea-level rise, if at all. Physical stratification is well preserved in cores from areas of rapid progradation, consistent with energetic transport processes and an ample sediment

  14. Utilisation agricole de plantes aquatiques, notamment en tant qu'amendement des sols, dans la province de Thua Thien Hue, Centre Vietnam. 2. Relevé des pratiques de terrain, enquête auprès des agriculteurs, impact potentiel sur l'écologie de la lagune de Tam Giang

    Directory of Open Access Journals (Sweden)

    Chiang, CN.

    2009-01-01

    Full Text Available Use of Aquatic Plants, mainly as Soil Amendment, in the Thua Thien Hue Province, Central Vietnam. 2. Field Practices, Survey among Farmers, and Possible Impact on the Tam Giang Lagoon Ecology. The sandy soils of the coastal area of Central Vietnam, particularly in the Thua Thien Hue Province, have a limited natural fertility. Amending these soils with organic materials is the most important way to improve their productivity. In this region, numerous farmers are fertilizing their soils with aquatic plants collected from the Tam Giang lagoon. The present study aims to provide quantitative and qualitative data on this local practice, based on a survey among the farmers and on field observations carried out at the beginning of 2005. Among the 60 interviewed farmers, 38 (63% use aquatic plants to fertilize their crops, mainly sweet potatoes, cassava, chili, tobacco, and vegetables. Rice and peanuts are not commonly fertilized by this way. This practice is particularly popular in the communes located in the North of the lagoon, where the proportion of lands fertilized in this way is sometimes higher than 20%, whereas in the sandy zone between the lagoon and the sea, it is generally around 10 to 20%. The most used species are Najas indica, Vallisneria spiralis, Potamogeton malaianus plus various algae species. Following the farmers' estimations, the quantities actually used vary from 0.45 to 10 tons of fresh matter per year and per farm, with an average of 3.5 tons. The farmers are not at all conscious of the possible ecological impact of collecting plants for agricultural uses, particularly on the sustainability of the lagoon resources. Many of them believe that the plant biomass reduction that they have observed in recent years in the lagoon is mainly due to the development of aquaculture.

  15. Macroalgae, nutrient cycles, and pollutants in the lagoon of Venice

    Energy Technology Data Exchange (ETDEWEB)

    Sfriso, A.; Pavoni, B.; Marcomini, A.; Orio, A.A. (Department of Environmental Sciences, Venezia (Italy))

    1992-12-01

    The Lagoon of Venice is a wide, shallow coastal basin that extends for about 50 km along the northwest coast of the Adriatic Sea. The lagoon has been substantially modified through the actions of man over the last century through the artificial control of the hydraulic dynamics of the lagoon including the construction of channels to facilitate navigation. The lagoon is subjected to considerable pollutant loading through the drainage of land under cultivation, municipal sewage, and industrial effluents. In this paper are reported the results of observations designed to document recent changes in macroalgal species composition, seasonal cycles of primary producers and nutrient levels, and the effects of the macroalgal community on concentrations of organic and inorganic pollutants. The dominant macroalgae in the lagoon was Ulva rigida, and the levels of plant nutrients and pollutants were influenced by the seasonal cycles of the macroalgal community. 44 refs., 11 figs., 2 tabs.

  16. Geoelectrical signals of geologic and hydrologic processes in a fringing reef lagoon setting

    Science.gov (United States)

    Befus, Kevin M.; Cardenas, M. Bayani; Tait, Douglas R.; Erler, Dirk V.

    2014-09-01

    Coastal groundwater may discharge into nearshore and offshore waters forced by terrestrial fluxes, controlled by local geology, and modulated by the hydrodynamics of littoral water. We investigated the electrical signature of these features with a dense, multiscale network of electrical resistivity tomography (ERT) surveys in the Muri Lagoon of Rarotonga, Cook Islands. The ERT surveys spanned from onshore to 400 m into the lagoon and used standard electrodes on land and across the foreshore, submerged electrodes in the shallow subtidal zone, and floating electrodes towed throughout the reef lagoon by a boat. ERT surveys on land mapped a typical freshwater lens underlain by a saltwater wedge, but with possible deviations from the classical model due to an adjacent tidal creek. Further inland, ERT surveys imaged a layer of lava flow deposits that is potentially a confining hydrogeologic unit; this unit was used to constrain the expected electrical resistivity of these deposits below the lagoon. ERT surveys across the intertidal zone and into the lagoon indicated fresh groundwater and porewater salinity patterns consistent with previous small-scale studies including the seaward extension of fresh groundwater pathways to the lagoon. Electrical resistivity (ER) variations in the lagoon subsurface highlighted heterogeneities in the lagoon structure that may focus submarine groundwater discharge (SGD) through previously unknown buried lava flow deposits in the lagoon. A transition to higher ER values near the reef crest is consistent with the ER signature of porosity reduction due to ongoing differential cementation of reef deposits across the lagoon. The imaged coastal hydrostratigraphic heterogeneity may thus control terrestrial and marine porewater mixing, support SGD, and provide the pathways for groundwater and the materials it transports into the lagoon. This hydrogeophysical investigation highlighted the spatial heterogeneity of submarine coastal geology and its

  17. Influence of an intensive agricultural drainage basin on the seasonal distribution of organic pollutants in seawater from a Mediterranean coastal lagoon (Mar Menor, SE Spain).

    Science.gov (United States)

    Moreno-González, R; Campillo, J A; León, V M

    2013-12-15

    The seasonal distribution of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, organophosphorus pesticides, triazines and other organic pollutants in surface seawater from the Mar Menor lagoon (SE Spain) was characterized from spring 2009 to winter 2010 by stir bar sorptive extraction and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry (SBSE-GC-MS). The most ubiquitous pollutants were chlorpyrifos, chlortal-dimethyl, terbuthylazine, naphthalene and propyzamide throughout the year. Insecticides and herbicides were predominant in summer and spring, and fungicides were more abundant in autumn and winter. Chlorpyrifos was predominant in autumn and spring; herbicides (propyzamide, terbuthylazine and terbuthylazine-desethyl) in autumn and fungicides (flutolanil, boscalid, cyprodinil) in autumn and winter. The highest concentrations for the majority of pollutants were detected in autumn as consequence of air and surface/ground water inputs, and above all of desorption from terrigenous materials deposited in sediments by two intense flash flood events (September 2009). Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Catch variability and growth of pink shrimp (Farfantepenaeus paulensis in two coastal lagoons of uruguay and their relationship with ENSO events

    Directory of Open Access Journals (Sweden)

    Orlando Santana

    2015-09-01

    Full Text Available AbstractThe pink shrimp Farfantepenaeus paulensis (Pérez Farfante, 1967 is distributed along the Atlantic Coast from Bahia (Brazil to Mar del Plata (Argentina. The larval stages enter the Uruguayan brackish water lagoons during late spring to summer associated with tidal currents of the Brazilian Current. In such environments the growth is accelerated and in early autumn the individuals attain commercial size, supporting important regional artisanal fisheries. The pink shrimp catches from 1988 to 2013 were analyzed and related to phenomena of climate variability in ENSO events and to the growth of the species. The total catch ranges from 0.7 to 162 tons. The variation in catches has a negative relationship with the varied climatic events caused by El Niño. Growth parameters yielding values of L ∞ = 177 mm (total carapace length and K = 1.48 for the period 2009-2013. These values differ slightly from those calculated for natural populations in southern Brazil, suggesting that the population is the same and thus implying the need for coordinated fisheries management between the two countries.

  19. Floating Aquatic Macrophytes Decrease the Methane Concentration in the Water Column of a Tropical Coastal Lagoon: Implications for Methane Oxidation and Emission

    Directory of Open Access Journals (Sweden)

    André Luiz dos Santos Fonseca

    2017-05-01

    Full Text Available ABSTRACT In wetlands, the knowledge accumulated on the role of aquatic plants in the methane cycle focused on emergent macrophytes, to the detriment of other typologies. Herein, we evaluated whether the free-floating macrophyte Salvinia auriculata Aubl. and the floating-leaved macrophyte Eichhornia azurea (Sw. Kunth. decrease the water column methane concentrations compared to a plant-free surface. We prepared microcosms by inserting an individual of S. auriculata or of E. azurea into chambers filled with lagoon water previously bubbled with CH4. Another set of chambers was incubated only with the prepared water, representing the plant-free surface. Half of the chambers were kept in the dark and half in sunlight to simulate a diel cycle. We observed greater loss of CH4, higher O2 uptake and lower CO2 outflow in the plants treatments. The decrease in methane concentrations in the E. azurea treatments was 93.5% in the light and 77.2% in the dark. In the S. auriculata treatments, the decreases were 74.2% and 67.4% in the light and in the dark, respectively. In plant-free surface the decrease was 58.7% in the light and 36.3% in the dark. These results indicate a role of floating aquatic macrophytes in the methane cycle in the water column. Moreover, our results suggest a diel variation of methane oxidation and methane emission, according to the differences observed in O2 uptake and CO2 outflow between dark and light conditions. Thus, future predictions of global methane budget should include the role played by floating aquatic macrophytes.

  20. Long-term observations on salinity dynamics in a tideless shallow coastal lagoon of the Southern Baltic Sea coast and their biological relevance

    Science.gov (United States)

    Schumann, R.; Baudler, H.; Glass, Ä.; Dümcke, K.; Karsten, U.

    2006-05-01

    The Darß-Zingst Bodden Chain (DZBC) is a tideless shallow inner coastal water of the Southern Baltic Sea. Important water volumes are exchanged with the Baltic Sea in dependence of wind direction and strength, water levels and coastal water currents. The Bodden chain is a system of 4 consecutive water basins which are connected via narrow streams with the opening to the Baltic Sea in the west. The innermost Bodden basins are predominantly influenced by freshwater and the outermost basins receive more Baltic Sea water. The whole Bodden chain was subject to a substantial eutrophication for decades until 1990. Macrophytes vanished, phytoplankton formed dense blooms throughout the growing season and organic matter accumulated in the system. The water mixing varies in time and is very different for the separate water basins what obscures trends of biological parameters, e.g. phytoplankton composition, primary production and benthic organisms. Thus, the process of 30 years' eutrophication and especially of re-mesotrophication for the last 15 years is difficult to describe and verify without an indicator for the portion of mesotrophic Baltic Sea water at the monitoring locations. Therefore, variability of salinity was described on short-term, seasonal and long-term ranges as well as spatial gradients. The data set is based on 29 years of daily measurements for the central part of the Bodden chain. In contrast to deep fjords of the northern Baltic Sea, maximum salinity changes were ca. 1 psu per day not for more than consecutive 5 days in the same direction. In contrast to the outer coastal waters of the Baltic Sea, lowest salinities occurred always in early spring and highest in autumn indicating a completely different set of meteorological and hydrological parameters affecting seasonality. Annual averages of Bodden salinity correlated with values of the Baltic Sea, but deviations from the mean were twice as high. The long-term mean at the central Bodden chain (Zingster

  1. State-of-the-lagoon reports as vehicles of cross-disciplinary integration

    NARCIS (Netherlands)

    Zaucha, J.; Davoudi, S.; Slob, A.; Bouma, G.; Meerkerk, I. van; Oen, A.M.P.; Breedveld, G.D.

    2016-01-01

    An integrative approach across disciplines is needed for sustainable lagoon and estuary management as identified by integrated coastal zone management. The ARCH research project (Architecture and roadmap to manage multiple pressures on lagoons) has taken initial steps to overcome the boundaries

  2. Brazil The Duck Lagoon

    Science.gov (United States)

    2002-01-01

    This Multi-angle Imaging SpectroRadiometer (MISR) image of Brazil covers an area of about 298 kilometers x 358 kilometers, and was captured by the instrument's vertical-viewing (nadir) camera on December 27, 2001. The 'Lagoa dos Patos', in the Brazilian state of Rio Grande do Sul, translates to 'the Duck Lagoon'. It was named by 16th century Jesuit settlers, who asked the King of Spain to grant them title to the lagoon so that they could breed ducks. The King consented, but revoked his edict when he discovered that the 'duck-pond' (measuring about 14,000 square kilometers) was one of the largest lagoonal systems in the world. Note the sediment plume emanating from the southern end of the lagoon. Sailors in the 16th century imagined this outlet to be the mouth of a large river. Early Portuguese explorers mistook the entrance to the lagoon for the mouth of a great river and called it the Rio Grande. A series of wave-like points and curls form 'cusps' on the inner shores of the lagoon. The lagoon's characteristics change with short-term tide-induced cyclic perturbations, and with longer term large scale meteorological conditions. The distinctive wavelike 'cusps' along the inner shores result from the circulation, erosion and accumulation of sediments driven by wind and tidal action. The El Nino Southern Oscillation (ENSO) circulation affects precipitation amount and continental runoff, thereby changing the contents of the lagoon waters. High rainfall and increased freshwater discharge during El Nino events correspond with elevated dissolved nutrient concentrations and increased phytoplankton growth. La Nina years are dry and the associated low rainfall reduces the freshwater recharge to the lagoon, causing an increase in salinity. Occasional blooms of toxic cyanobacteria (Microcystis aeruginosa), have been registered in the lagoon when nutrient concentrations are elevated. A number of reeds and grasses are important to the lagoon estuary, including widgeon grass

  3. The role played by aquatic macrophytes regarding CO2 balance in a tropical coastal lagoon (Cabiúnas Lagoon, Macaé, RJ)/O papel desempenhado pelas macrófitas aquáticas em relação ao balanço de CO2 em uma lagoa costeira tropical (Lagoa Cabiúnas, Macaé, RJ)

    National Research Council Canada - National Science Library

    Anderson da Rocha Gripp; Claudio Cardoso Marinho; Lúcia Fernandes Sanches; Antonella Petruzzella; Francisco de Assis Esteves

    2013-01-01

      This study aimed to evaluate the importance of the littoral region on the CO2 balance in the Cabiunas Lagoon, while also considering the contribution of the limnetic region and of Typha domingensis...

  4. Nitrogen isotopic composition of organic matter from a 168 year-old coral skeleton: Implications for coastal nutrient cycling in the Great Barrier Reef Lagoon

    Science.gov (United States)

    Erler, Dirk V.; Wang, Xingchen T.; Sigman, Daniel M.; Scheffers, Sander R.; Martínez-García, Alfredo; Haug, Gerald H.

    2016-01-01

    Ongoing human activities are known to affect nitrogen cycling on coral reefs, but the full history of anthropogenic impact is unclear due to a lack of continuous records. We have used the nitrogen isotopic composition of skeleton-bound organic matter (CS-δ15N) in a coastal Porites coral from Magnetic Island in the Great Barrier Reef as a proxy for N cycle changes over a 168 yr period (1820-1987 AD). The Magnetic Island inshore reef environment is considered to be relatively degraded by terrestrial runoff; given prior CS-δ15N studies from other regions, there was an expectation of both secular change and oscillations in CS-δ15N since European settlement of the mainland in the mid 1800s. Surprisingly, CS-δ15N varied by less than 1.5‰ despite significant land use change on the adjacent mainland over the 168-yr measurement period. After 1930, CS-δ15N may have responded to changes in local river runoff, but the effect was weak. We propose that natural buffering against riverine nitrogen load in this region between 1820 and 1987 is responsible for the observed stability in CS-δ15N. In addition to coral derived skeletal δ15N, we also report, for the first time, δ15N measurements of non-coral derived organic N occluded within the coral skeleton, which appear to record significant changes in the nature of terrestrial N inputs. In the context of previous CS-δ15N records, most of which yield CS-δ15N changes of at least 5‰, the Magnetic Island coral suggests that the inherent down-core variability of the CS-δ15N proxy is less than 2‰ for Porites.

  5. Benthic primary production budget of a Caribbean reef lagoon (Puerto Morelos, Mexico.

    Directory of Open Access Journals (Sweden)

    Malik S Naumann

    Full Text Available High photosynthetic benthic primary production (P represents a key ecosystem service provided by tropical coral reef systems. However, benthic P budgets of specific ecosystem compartments such as macrophyte-dominated reef lagoons are still scarce. To address this, we quantified individual and lagoon-wide net (Pn and gross (Pg primary production by all dominant functional groups of benthic primary producers in a typical macrophyte-dominated Caribbean reef lagoon near Puerto Morelos (Mexico via measurement of O₂ fluxes in incubation experiments. The photosynthetically active 3D lagoon surface area was quantified using conversion factors to allow extrapolation to lagoon-wide P budgets. Findings revealed that lagoon 2D benthic cover was primarily composed of sand-associated microphytobenthos (40%, seagrasses (29% and macroalgae (27%, while seagrasses dominated the lagoon 3D surface area (84%. Individual Pg was highest for macroalgae and scleractinian corals (87 and 86 mmol O₂ m(-2 specimen area d(-1, respectively, however seagrasses contributed highest (59% to the lagoon-wide Pg. Macroalgae exhibited highest individual Pn rates, but seagrasses generated the largest fraction (51% of lagoon-wide Pn. Individual R was highest for scleractinian corals and macroalgae, whereas seagrasses again provided the major lagoon-wide share (68%. These findings characterise the investigated lagoon as a net autotrophic coral reef ecosystem compartment revealing similar P compared to other macrophyte-dominated coastal environments such as seagrass meadows and macroalgae beds. Further, high lagoon-wide P (Pg: 488 and Pn: 181 mmol O₂ m(-2 lagoon area d(-1 and overall Pg:R (1.6 indicate substantial benthic excess production within the Puerto Morelos reef lagoon and suggest the export of newly synthesised organic matter to surrounding ecosystems.

  6. Trends analysis relating to pollution in Sakumo Lagoon, Ghana ...

    African Journals Online (AJOL)

    Sakumo Lagoon, situated near Accra, is a Ramsar-listed coastal wetland threatened by urban and agricultural waste, being located in an urban area where access to domestic and waste disposal facilities is a major problem. The aim of this study was to assess the pollution status as well as trends, in terms of pollution ...

  7. Composition and abundance of zooplankton community of an impacted estuarine lagoon in Northeast Brazil

    Directory of Open Access Journals (Sweden)

    LR Almeida

    Full Text Available Guaraíras Lagoon is a shallow coastal lagoon subject to intense human impacts, including shrimp aquaculture, urban expansion and agricultural activities, and is therefore vulnerable to eutrophication. With the aim of detecting the effects of human-mediated disturbance and environmental change in the lagoon, a spatial-temporal study was conducted in order to assess the actual ecological status of the lagoon and the species composition and density of the mesozooplankton, highlighting copepod assemblages. Algal biomass (chlorophyll-a and total phosphorus concentration indicated that the lagoon is a meso-eutrophic coastal system in the inner part, and is oligotrophic in the areas influenced by the marine waters. High salinities were recorded in the lagoon, characterizing the lagoon as a coastal-marine ecosystem, rather than true estuarine. Mesozooplankton abundance fluctuated widely and showed marked spatial heterogeneity. The copepod assemblage was characterized by a coastal/estuarine group dominated by Oithona spp., Acartia lilljeborgi and Parvocalanus crassirostris in the inner areas of the lagoon, and a marine group characterized by the copepods Paracalanus quasimodo, Calanopia americana, Corycaeus (C. speciosus and Monstrilloida in the area of marine influence. Thus, the spatial variability in the distribution of mesozooplankton species can be ascribed to the presence of a horizontal gradient of salinity and trophic conditions. Overall, the results showed that spatial variation in the water physicochemical characteristics of Guarairas Lagoon have significant effects on the structure and repartition of the mesozooplankton assemblages, which may potentially affect the functioning and biodiversity of this coastal ecosystem.

  8. Saccocoelioides lamothei n. sp. from Dormitator latifrons (Pisces: Eleotridae from coastal lagoons of Guerrero, Mexico Saccocoelioides lamothei n. sp. de Dormitator latifrons (Pisces: Eleotridae de lagunas costeras de Guerrero, México

    Directory of Open Access Journals (Sweden)

    M. Leopoldina Aguirre-Macedo

    2008-08-01

    Full Text Available A new haploporid trematode, Saccocoelioides lamothei n. sp., is described from the intestine of the Pacific fat sleeper, Dormitator latifrons (Richardson, 1844 from 2 coastal lagoons of Guerrero, Mexico. The new species is characterized by the presence of diffuse eye-spot pigmentation in the forebody, 2 sac-like caeca ending pretesticularly, ventral sucker pre-equatorial and miracidium with pigmented eye-spots in eggs. It differs from all other congeneric species by having a small, pyriform to slightly elongated body, a short but conspicuous prepharynx and sac-like caeca terminating pretesticularly, an extreme posterior position of the testis, a small spherical to elongated ovary, vitelline follicles irregular in shape and size and reaching the ovary level, the uterus extending from the testicular zone to the acetabular region, with numerous relatively large eggs.En este trabajo se describe una especie nueva de tremátodo de la familia Haploporidae, Saccocoelioides lamothei n. sp. recolectado del intestino del popoyote Dormitator latifrons (Richardson, 1844 en 2 lagunas costeras del estado de Guerrero, México. La especie nueva se caracteriza por la presencia de remanentes de las manchas oculares dispersas en la parte anterior del cuerpo; 2 ciegos intestinales saculares que terminan pretesticularmente o apenas tocando el borde anterior del testículo, acetábulo preecuatorial y huevos conteniendo miracidios con manchas oculares. Esta especie nueva se diferencia de otras del mismo género por tener un cuerpo pequeño, piriforme a ligeramente alargado, una prefaringe muy pequeña pero conspicua y ciegos intestinales que terminan pretesticularmente, un testículo en el extremo posterior del cuerpo, un ovario pequeño, esférico a cilíndrico, difícil de distinguir, con folículos vitelinos de forma y tamaño irregulares, y un útero dispuesto entre el acetábulo y la región testicular con huevos relativamente grandes y numerosos.

  9. Mussel farming as a large-scale bioengineering tool: a numerical modelling case study in Rødsand lagoon, Denmark

    DEFF Research Database (Denmark)

    Forsberg, Pernille Louise; Ernstsen, Verner Brandbyge; Lumborg, Ulrik

    Rødsand lagoon in southeast Denmark is a non-tidal coastal lagoon, which is home to a wide range of marine flora and fauna and is protected under Natura 2000. An increase in turbidity within the lagoon may reduce the ecosystem health due to hindered light penetration. A threat to the lagoonal...... spill of sediment, which could increase the longshore sediment influx to Rødsand lagoon. Mussels can reduce the SSC in marine environments (Schröder et al., 2014), why the implementation of a mussel farm has been considered as a management option. In the present study we developed a module to include...... ecosystem is related to future increasing storm intensities (Olesen et al., 2014), which are presumed to increase the suspended sediment concentration (SSC) within the lagoon. Furthermore the planned construction of a tunnel between Germany and Denmark may propose a threat to the lagoon due to a possible...

  10. Cyanobacterial and chemical composition of the stromatolites in Salgada lagoon, Neogene of Rio de Janeiro state, Brazil

    OpenAIRE

    Sinda Beatriz Vianna Carvalhal Gomes; Fernanda Campante Magina; Siglia Andressa Pinto Monteiro do Nascimento Alves; Loreine Hermida da Silva e Silva

    2013-01-01

    Salgada lagoon is a coastal aquatic body in northern Rio de Janeiro state. The geological evolution of the lagoon is associated with the oscillation of sea level during the Late Neogene. The lagoon presents microbial mats, stratiform stromatolites, individual and continuous stromatolites. Stromatolites are laminated carbonate build-ups formed by the metabolic activity of microbial mats. This study identified 31 species of cyanobacteria in stromatolites and microbial mats. The Family Synechoco...

  11. A Blue Lagoon Function

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2007-01-01

    We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$.......We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$....

  12. Planning Joint Vietnam Ocean Circulation Studies

    Science.gov (United States)

    2013-09-30

    We intend to make new Lagrangian and Eulerian observations to measure the seasonal circulation 1) in the coastal waters of Vietnam and 2) in the SCS...circulation models of the SCS and its coastal waters . Raise interest amongst Vietnamese scientists on Lagrangian circulation studies through multiple...an inexpensive micro-controller unit (MCU) was designed with support circuitry for onboard GPS, 5 SST, drogue detection, external barometer

  13. The marsh vegetation of Kleinmond Lagoon

    Directory of Open Access Journals (Sweden)

    M. O'Callaghan

    1994-12-01

    Full Text Available The vegetation of Kleinmond Lagoon suggests that this system is in transition from an estuary to a coastal lake. Two major types of vegetation were recognized, one which is subjected to soil and water conditions of marine origin and the other which is subjected to conditions of terrestrial origin. These vegetation types are discussed and compared to the vegetation of other estuarine systems. Artificial manipulations of the mouth seem to have resulted in sediment deposition and a freshening of the system. These unseasonable manipulations also threaten the continued existence of a number of species in the system.

  14. The marsh vegetation of Kleinmond Lagoon

    Directory of Open Access Journals (Sweden)

    M. O'Callaghan

    1994-10-01

    Full Text Available The vegetation of Kleinmond Lagoon suggests that this system is in transition from an estuary to a coastal lake. Two major types of vegetation were recognized, one which is subjected to soil and water conditions of marine origin and the other which is subjected to conditions of terrestrial origin. These vegetation types are discussed and compared to the vegetation of other estuarine systems. Artificial manipulations of the mouth seem to have resulted in sediment deposition and a freshening of the system. These unseasonable manipulations also threaten the continued existence of a number of species in the system.

  15. Integrated Approach to Transboundary Waters Management, such as a Rivermouth and a Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.H.; Lee, B.K.; Yoo, H.J. [Korea Environment Institute, Seoul (Korea); Kang, D.S.; Nam, J.H. [Korea Maritime Institute, Seoul (Korea)

    2001-12-01

    Estuaries and coastal lagoons (estuarine environments) are typical transitional ecosystems between land and sea, where sea water is mixed with fresh water. It is well known that estuarine environments are very valuable ecosystems because of their unique ecological functions and geographical features, as well as socioeconomic values. These precious estuaries, however, have become severely deteriorated and damaged by human activities through watersheds and intensive coastal developments. In this respect, this study aims to develop integrated management strategies for protection, improvement, and restoration of estuarine environments that would support sustainable uses of those precious natural resources. This study found that regardless of their ecological value, estuaries and coastal lagoons in Korea have deteriorated due to a lack of appropriate management systems and imprudent development and utilization. Furthermore, considering the fact that destruction of the estuaries has been caused by national development projects, the study urges the Korean government to change its development-oriented policies on estuaries and coastal lagoons to more sustainable ones so that future generations may enjoy the benefits from healthy natural estuaries and coastal lagoons. The Korean government, thus, needs to declare that it will no longer promote any development-oriented policy that might destroy valuable estuaries and coastal lagoons, in preparing for the 2002 WSSD which will be held in South Africa in 2002. (author). 175 refs., 72 figs., 95 tabs.

  16. Anthropogenic Enrichment and Nutrients in Some Tropical Lagoons of Ghana, West Africa

    Science.gov (United States)

    As part of a larger study of demographic change in coastal Ghana, we measured the concentrations of major plant nutrients and phytoplankton chlorophyll in eight coastal lagoons with different land use and human population density. The purpose of our study was to relate human acti...

  17. Seasonal changes in a fish assemblage associated with mangroves in a coastal lagoon of Baja California Sur, Mexico Cambios estacionales de la comunidad de peces asociada a zonas de manglar en una laguna costera de Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Jesús Rodríguez-Romero

    2011-07-01

    Full Text Available The fish assemblage in a coastal lagoon with mangroves known as "Rancho Bueno" was determined and associated with environmental parameters. We used an experimental otter trawl net to catch the fish, and 62 fish species were identified from 48 genera and 30 families. The most abundant species were: Etropus crossotus, Eucinostomus gracilis, Paralabrax maculatofasciatus, Sphoeroides annulatus, and Eucinostomus dowii. The water temperature changed seasonally, being warm from July through December and cold from January through June. We found more fish species during the warm season than during the cold season. The southern area of the coastal lagoon had the highest diversity and species richness. The small size of the fishes registered confirms the ecological role of coastal lagoons as nursery areas that offer protection and feeding to commercially important fish near Bahía Magdalena, Mexico.Se determinó la estructura de peces asociada a factores ambientales en una laguna costera con manglar denominada "Rancho Bueno". Se utilizó una red de arrastre experimental para la captura y se identificaron 62 especies de peces de 48 géneros y 30 familias. Las especies más importantes fueron Etropus crossotus, Eucinostomus gracilis, Paralabrax maculatofasciatus, Sphoeroides annulatus y Eucinostomus dowii. La temperatura del agua varió estacionalmente, siendo cálida de julio a diciembre y fría de enero a junio. Se registró un mayor número de especies de peces durante la época cálida comparada con la época fría. La zona sur de la laguna costera presentó una mayor diversidad y riqueza específica. El menor tamaño de los peces registrados, confirma el papel ecológico de las lagunas costeras, consideradas como áreas de crianza las cuales proporcionan protección y alimentación a los peces de importancia comercial cerca de Bahía Magdalena, México.

  18. Degradation of sec-hexylbenzene and its metabolites by a biofilm-forming yeast Trichosporon asahii B1 isolated from oil-contaminated sediments in Quangninh coastal zone, Vietnam.

    Science.gov (United States)

    Nhi-Cong, Le Thi; Mai, Cung Thi Ngoc; Minh, Nghiem Ngoc; Ha, Hoang Phuong; Lien, Do Thi; Tuan, Do Van; Quyen, Dong Van; Ike, Michihiko; Uyen, Do Thi To

    2016-01-01

    This article reports on the ability of yeast Trichosporon asahii B1 biofilm-associated cells, compared with that of planktonic cells, to transform sec-hexylbenzene and its metabolites. This B1 strain was isolated from a petroleum-polluted sediment collected in the QuangNinh coastal zones in Vietnam, and it can transform the branched aromatic hydrocarbons into a type of forming biofilm (pellicle) more efficiency than that the planktonic forms can. In the biofilm cultivation, seven metabolites, including acetophenone, benzoic acid, 2,3-dihydroxybenzoic acid, β-methylcinnamic acid, 2-phenylpropionic acid, 3-phenylbutyric acid, and 5-phenylhexanoic acid were extracted by ethyl acetate and analyzed by HPLC and GC-MS. In contrast, in the planktonic cultivation, only three of these intermediates were found. An individual metabolite was independently used as an initial substrate to prove its degradation by biofilm and planktonic types. The degradation of these products indicated that their inoculation with B1 biofilms was indeed higher than that observed in their inoculation with B1 planktonic cells. This is the first report on the degradation of sec-hexylbenzene and its metabolites by a biofilm-forming Trichosporon asahii strain. These results enhance our understanding of the degradation of branched-side-chain alkylbenzenes by T. asahii B1 biofilms and give a new insight into the potential role of biofilms formed by such species in the bioremediation of other recalcitrant aromatic compounds.

  19. EPA Collaboration with Vietnam

    Science.gov (United States)

    Vietnam, one of Asia’s emerging economies, is an important environmental partner for EPA in Asia. EPA’s current cooperation with Vietnam primarily focuses on dioxin remediation and technical assistance to reduce methane emissions.

  20. Lagoon Restoration Project: Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    This project is a multiyear effort focusing on energy flow in the Palace of Fine Arts lagoon just outside the Exploratorium in San Francisco. Phase 1 was a pilot study to determine the feasibility of improving biological energy flow through the small freshwater lagoon, using the expertise and resources of an environmental artist in collaboration with museum biologists and arts department staff. The primary outcome of Phase 1 is an experimental fountain exhibit inside the museum designed by public artist Laurie Lundquist with Exploratorium staff. This fountain, with signage, functions both as a model for natural aeration and filtration systems and as a focal point for museum visitors to learn about how biological processes cycle energy through aquatic systems. As part of the study of the lagoon`s health, volunteers continued biweekly bird consus from March through September, 1994. The goal was to find out whether the poor water quality of the lagoon is affecting the birds. Limited dredging was undertaken by the city Parks and Recreation Department. However, a more peermanent solution to the lagoon`s ecological problems would require an ambitious redesign of the lagoon.

  1. Economic analysis of the environmental impact on marine cage lobster aquaculture in Vietnam

    OpenAIRE

    Ly, Nguyen Thi Y

    2009-01-01

    In Vietnam, marine cage lobster aquaculture has been expanding significantly over the last years. Besides the economic contribution for locals living in the coastal areas in Central of Vietnam, this industry has created some problems that are relating to the marine environmental protection where trash fish feed is predominant. This paper investigates the environmental impact on cage marine lobster aquaculture in Vietnam by using the Change of Productivity method in which nitrogen releasing fr...

  2. Vietnam: Historians at War

    Science.gov (United States)

    Moyar, Mark

    2008-01-01

    Although the Vietnam War ended more than thirty years ago, historians remain as divided on what happened as the American people were during the war. Mark Moyar maps the ongoing battle between "orthodox" and "revisionist" Vietnam War historians: the first group, those who depict Vietnam as a bad war that the United States should…

  3. Surface Water Quality Survey of Northern Indian River Lagoon from Sebastian Inlet to Mosquito Lagoon

    Science.gov (United States)

    Weaver, R. J.; Webb, B. M.

    2012-12-01

    Following news of an emerging brown tide algal bloom in the northern Indian River Lagoon (IRL), researchers sought to gain insight into the surface water quality in the IRL, as well as the extent of the algae coverage. A Portable SeaKeeper from YSI, mounted to a personal watercraft-based coastal profiling system, autonomously collected and analyzed the surface water. The system operates by recording sample data every 12 seconds while continuously underway at speeds up to and greater than 50 km/hr. The researchers covered a transect that started at Sebastian Inlet and followed a zig-zag path extending up through the Haulover Canal and into the Mosquito Lagoon. The survey path covered 166.7 km, and collected 2248 samples. Along the way stops were made at water quality stations used by the Saint John's River Water Management District, so that the data collected can be incorporated into ongoing monitoring efforts. The system analyzed the surface water for dissolved oxygen, pH, chlorophyll-a, salinity, temperature, turbidity, refined fuels, and CDOM. In the two days following the lagoon survey, the inlets at Port Canaveral and Sebastian were also surveyed for tidal currents and hydrography. The IRL transect survey data recorded evidence of the southern extent of the algae bloom in both chlorophyll-a and pH levels. Visual evidence of the bloom was striking as the water in the northern IRL turned a milk chocolaty brown color. Chlorophyll-a levels in the two inlets suggested bloom activity at these locations; however this bloom was different. This oceanic bloom was a result of a persistent upwelling event along the East Florida shelf, and the color was a paler green-yellow. The near-synoptic nature of the comprehensive lagoon survey, conducted in just over 7 hours, allows researchers to obtain a better understanding of water quality in coastal lagoons. Elevated levels of salinity, temperature, and refined fuels in the northern IRL indicate a low exchange rate and absence

  4. Fingerprints of lagoonal life: Migration of the marine flatfish Solea solea assessed by stable isotopes and otolith microchemistry

    Science.gov (United States)

    Dierking, Jan; Morat, Fabien; Letourneur, Yves; Harmelin-Vivien, Mireille

    2012-06-01

    The commercially important marine flatfish common sole (Solea solea) facultatively uses NW Mediterranean lagoons as nurseries. To assess the imprint left by the lagoonal passage, muscle carbon (C) and nitrogen (N) isotope values of S. solea juveniles caught in Mauguio lagoon in spring (shortly after arrival from the sea) and in autumn (before the return to the sea) were compared with values of juveniles from adjacent coastal marine nurseries. In addition, in the lagoon, sole otolith stable isotope (C and oxygen (O)) and elemental (11 elements) composition in spring and autumn, and the stable isotope composition (C and N) of organic matter sources in autumn, were determined. Overall, our data indicate that a distinct lagoonal signature existed. Specifically, lagoon soles showed a strong enrichment in muscle tissue 15N (>6‰) compared to their coastal relatives, likely linked to sewage inputs (see below), and a depletion in 13C (1-2‰), indicative of higher importance of 13C depleted terrestrial POM in the lagoon compared to coastal nurseries. In addition, over the time spent in the lagoon, sole otolith δ13C and δ18O values and otolith elemental composition changed significantly. Analysis of the lagoon sole foodweb based on C and N isotopes placed sediment particulate organic matter (POM) at the base. Seagrasses, formerly common but in decline in Mauguio lagoon, played a minor role in the detritus cycle. The very strong 15N enrichment of the entire foodweb (+7 to +11‰) compared to little impacted lagoons and coastal areas testified of important human sewage inputs. Regarding the S. solea migration, the analysis of higher turnover and fast growth muscle tissue and metabolically inert and slower growth otoliths indicated that soles arrived at least several weeks prior to capture in spring, and that no migrations took place in summer. In the autumn, the high muscle δ15N value acquired in Mauguio lagoon would be a good marker of recent return to the sea, whereas

  5. Aquatic invertebrate's distribution in a freshwater coastal lagoon of southern Brazil in relation to water and sediment characteristics Distribuição de invertebrados aquáticos em uma lagoa costeira de água doce ao sul do Brasil em relação às características de água e sedimento

    Directory of Open Access Journals (Sweden)

    Leonardo Kleba Lisboa

    2011-06-01

    Full Text Available AIM: The objective of this study was to evaluate the influence of water and sediment characteristics on the abundance, richness and diversity of the benthic invertebrate community in Peri lagoon, a freshwater coastal lagoon located in central coast of Santa Catarina State; METHODS: Samplings were performed in April, May and June 2009, in five different sites of Peri lagoon. The samples were taken with an Eckman-Birge drag, totalizing 60 for the invertebrate community, and 45 for sediment. Water physicochemical variables were also measured. Environmental influences in benthic community have been measured using a Canonical Correspondence Analysis (CCA. Linear regressions were also plotted for main correlations; RESULTS: A total of 5,535 specimens were collected, identified into 18 taxa. Tanaidacea was the most abundant representing 54% of relative abundance, followed by Diptera (23%, and Ostracoda (17%. The richest family was Chironomidae with 6 taxa. CCA results indicated positive correlation between Chaoborus and Stenocypris with local depth, and negative correlation between Odonata, Gastropoda, Cytheridella and Coleoptera with the finest grains of sediment, as well as between Tanaidacea, Lopescladius, Annelida and Nematoda with both organic matter (OM content in sediment and local depth. Linear regression analysis demonstrated inverse relation of Tanaidacea in response to OM (y = 0.6 - 0.62.OM and sand (y = 0.6 - 0.6.sand, and of Lopescladius in response to OM (y = 0.37 - 0.41.OM and sand (y = 0.37 - 0.46.sand. The fact that Peri lagoon has no marine influence and has Tanaidacea as the most abundant taxa, a group not expected in freshwaters, gives to this lagoon a particular relevance among coastal lagoons. The study concluded that sediment characteristics and local depth are more significant than water variables in determining the benthic community structure in Peri lagoon, which varied in accordance with different local conditions.OBJETIVO: O

  6. The high resolution mapping of the Venice Lagoon tidal network

    Science.gov (United States)

    Madricardo, Fantina; Foglini, Federica; Kruss, Aleksandra; Bellafiore, Debora; Trincardi, Fabio

    2017-04-01

    One of the biggest challenges of the direct observation of the ocean is to achieve a high resolution mapping of its seafloor morphology and benthic habitats. So far, sonars have mapped just 0.05% of the ocean floor with less than ten-meter resolution. The recent efforts of the scientific community have been devoted towards the mapping of both Deep Ocean and very shallow coastal areas. Coastal and transitional environments in particular undergo strong morphological changes due to natural and anthropogenic pressure. Nowadays, only about 5% of the seafloor of these environments † have been mapped: the shallowness of these environments has prevented the use of underwater acoustics to reveal their morphological features. The recent technological development of multibeam echosounder systems, however, enables these instruments to achieve very high performances also in such shallow environments. In this work, we present results and case studies of an extensive multibeam survey carried out in the Lagoon of Venice in 2013. The Lagoon of Venice is the biggest lagoon in the Mediterranean Sea with a surface of about 550 km2 and with an average depth of about 1 m. In the last century, the morphological and ecological properties of the lagoon changed dramatically: the surface of the salt marshes was reduced by 60% and some parts of the lagoon are deepening with a net sediment flux exiting from the inlets. Moreover, major engineering interventions are currently ongoing at the inlets (MOSE project). These changes at the inlets could affect substantially the lagoon environment. To understand and monitor the future evolution of the Lagoon of Venice, ISMAR within the project RITMARE (a National Research Programme funded by the Italian Ministry of University and Research) carried out an extensive survey, involving a team of more than 25 scientists, to collect high resolution (0.5 m) bathymetry of key study areas such as the tidal inlets and channels. Following a broad

  7. Bromide in some coastal and oceanic waters of India

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, F.P.; Dalal, V.N.K.

    Bromide concentration and bromide/chlorinity ratio are estimated in coastal waters of Goa, Minicoy Lagoon, Western Arabian Sea and Western Bay of Bengal. The influence of precipitation and river runoff on bromide and bromide/chlorinity ratio...

  8. [Species and size composition of fishes in Barra de Navidad lagoon, Mexican central Pacific].

    Science.gov (United States)

    González-Sansón, Gaspar; Aguilar-Betancourt, Consuelo; Kosonoy-Aceves, Daniel; Lucano-Ramírez, Gabriela; Ruiz-Ramírez, Salvador; Flores-Ortega, Juan Ramón; Hinojosa-Larios, Angel; de Asís Silva-Bátiz, Francisco

    2014-03-01

    Coastal lagoons are considered important nursery areas for many coastal fishes. Barra de Navidad coastal lagoon (3.76km2) is important for local economy as it supports tourism development and artisanal fisheries. However, the role of this lagoon in the dynamics of coastal fish populations is scarcely known. Thus, the objectives of this research were: to characterize the water of the lagoon and related weather conditions, to develop a systematic list of the ichthyofauna, and to estimate the proportion of juveniles in the total number of individuals captured of most abundant species. Water and fish samples were collected between March 2011 and February 2012. Physical and chemical variables were measured in rainy and dry seasons. Several fishing gears were used including a cast net, beach purse seine and gillnets of four different mesh sizes. Our results showed that the lagoon is most of the time euhaline (salinity 30-40ups), although it can be mixopolyhaline (salinity 18-30ups) during short periods. Chlorophyll and nutrients concentrations suggested eutrophication in the lagoon. Mean water temperature changed seasonally from 24.9 degrees C (April, high tide) to 31.4 degrees C (October, low tide). Considering ichthyofauna species, a total of 36 448 individuals of 92 species were collected, 31 of them adding up to 95% of the total of individuals caught. Dominant species were Anchoa spp. (44.6%), Diapterus peruvianus (10.5%), Eucinostomus currani (8.1%), Cetengraulis mysticetus (7.8%), Mugil curema (5.2%) and Opisthonema libertate (4.5%). The lagoon is an important juvenile habitat for 22 of the 31 most abundant species. These included several species of commercial importance such as snappers (Lutjanus argentiventris, L. colorado and L. novemfasciatus), snook (Centropomus nigrescens) and white mullet (Mugil curema). Other four species seem to use the lagoon mainly as adults. This paper is the first contribution on the composition of estuarine ichthyofauna in Jalisco

  9. Socio-Economic analysis and fishing activites of lagoon and marine ...

    African Journals Online (AJOL)

    Fishermen have distinctive social and economic features which affect their fishing operations. The study was therefore designed to identify the socio-economic characteristics of fisher-folks living in lagoon and coastal communities and assesses the fishing activities. Frequency distribution, percentages, chi-square and ...

  10. Distribution of foraminifera in the lagoons of certain Islands of the Lakshadweep Archipelago, Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Sivadas, P.; Narayanan, B.; Jayalakshmy, K.V.; Kutty, M.K.

    Foraminifera are very rare and those few present in the lagoons have been transported by water currents through passages of the reef. In general, Foraminifera of the coral reefs in the coastal waters of Indian peninsula are similar in their species composition...

  11. Exchange processes across sandy beach barriers: Examples from Malibu and Younger Lagoons, California

    Science.gov (United States)

    Swarzenski, P. W.; Dimova, N. T.; Izbicki, J. A.

    2010-12-01

    Estuarine systems in California can manifest themselves as shallow lagoons that are seasonally closed to the ocean by wave-built sand barriers. When a lagoon is physically isolated from the ocean, restricted circulation and sustained material inputs may cause eutrophication, low-oxygen conditions, and persistent algal blooms. During such times, the flow of water and material to the ocean must occur through a beach barrier rather than as surface-water runoff. This subsurface exchange can be modulated by the tides and expressed as a form of submarine groundwater discharge, SGD. Biogeochemically, this transport mode is much different than when a lagoon can exchange freely with the ocean, as redox conditions, organic matter concentrations, water residence times, and salinity can change dramatically. The objectives of this study were to: 1) characterize the seasonal patterns of SGD and associated nutrient loadings in two lagoonal systems that are intermittently isolated from the ocean; 2) assess the physical drivers of this exchange - can we identify the terrestrial versus marine forcing factors and what do these results imply for land / sea exchange along California’s coastline that has many such intermittent coastal systems? Two lagoons in California were studied: Younger Lagoon, an agriculturally-impacted coastal lagoon just north of Santa Cruz, and Malibu Lagoon located north of Los Angeles. Our observations during wet (October 2009 and April 2010) and dry conditions (July 2009) in Malibu captured both open- and closed-barrier scenarios. Lagoon water, groundwater, and seawater were analyzed for 222Rn, salinity, nutrients, DOC, and trace metals during all three field efforts. Initial data and calculations based on radon modeling indicate at least an order of magnitude larger groundwater flux to the lagoon during April 2010 (open barrier) as compared to July 2009, when the barrier was closed. A strong correlation (R2=0.85) between (NO2+NO3) concentrations in surface

  12. Comparing land use planning approaches in the Mekong Delta, Vietnam

    NARCIS (Netherlands)

    Trung, N.H.

    2006-01-01

    This thesis presents the application and comparison of three land-use planning (LUP) approaches in the coastal area of the Mekong Delta,Vietnam. The land use of the studied area is diverse, quickly shifting and

  13. Vietnam Urban Wastewater Review

    OpenAIRE

    World Bank

    2013-01-01

    Vietnam is facing the challenge of trying to keep pace with increasing environmental pollution associated with rapid urbanization, especially in the larger cities. Over the past 20 years, the Government of Vietnam has made considerable effort to develop urban sanitation policies, legislations and regulations, and to invest in urban sanitation including wastewater treatment systems. This st...

  14. Salinity levels as a factor of phyto planktonic structure and diversity remediation in a lagoon impact by human activities. (Bolmon Lagoon, Mediterranean Coast, France)

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle, S.; Charpy-Roubaud, C.; Ollivier, A.; Maasri, A.; Franquet, E.

    2009-07-01

    The Bolmon lagoon (south-eastern France) is located in the coastal hinterland of the Mediterranean Sea. It is connected to the salty Berre pond and in the other hand receives fresh waters from the La Cadiere River. This hyper-shallow lagoon has been classified in the early 70's as {beta} mixo-mesohaline. Bolmon lagoon is important for human activities (tourism, fishing) and for the preservation of the diversity of marine and birds species. In the last decades, the intensive urbanisation of its drainage basin induced a high eutrophication of its waters and, as a consequence, drastic modifications in the biodiversity and in the functioning os this ecosystem. (Author)

  15. Sustainability assessment of traditional fisheries in Cau Hai lagoon (South China Sea).

    Science.gov (United States)

    Marconi, Michele; Sarti, Massimo; Marincioni, Fausto

    2010-01-01

    Overfishing and progressive environmental degradation of the Vietnamese Cau Hai coastal lagoon appear to be threatening the ecological integrity and water quality of the largest estuarine complex of Southeast Asia. This study assessed the relationships between the density of traditional fisheries and organic matter sedimentary contents in Cau Hai lagoon. Data revealed that the density of stake traps (the most common fishing gear used in this lagoon), decreasing hydrodynamic energy in shallow water, causes the accumulation of a large fraction of organic matter refractory to degradation. The relationship between biopolymeric carbon (a proxy of availability of organic matter) and stake traps density fits a S-shape curve. The logistic equation calculated a stake traps density of 90 m of net per hectare, as the threshold over which maximum accumulation of organic matter occurs in Cau Hai. With such level of stake trap density, and assuming a theoretical stationary status of the lagoon, the time necessary for the system to reach hypoxic conditions has been calculated to be circa three weeks. We recommend that this density threshold should not be exceeded in the Cau Hai lagoon and that further analyses of organic loads in the sediment should be conducted to monitor the trophic conditions of this highly eutrophicated lagoon. 2010 Elsevier Ltd. All rights reserved.

  16. Metals in some lagoons of Mexico.

    Science.gov (United States)

    Vazquez, F G; Sharma, V K; Alexander, V H; Frausto, C A

    1995-02-01

    The concentrations of metals, Cd, Cu, Fe, Mn, Ni, Pb, and Zn were determined in some lagoons to establish the level of metal pollution. The lagoons studied were Alvarado lagoon, Veracruz; San Andres lagoon, Tamaulipas; and Terminos lagoon, Campeche. The concentrations were determined in water, oyster (Crassostrea virginica), and sediments. Metals were accumulated in either oysters or sediments. Cu and Zn were higher in oysters and Fe and Mn were higher in sediments. The results in water samples were compared with the limit established by the Secretaria de Ecologia and Desarrollo Urbano Report and briefly discussed.

  17. The ecofunctional quality index (EQI): a new tool for assessing lagoonal ecosystem impairment

    Science.gov (United States)

    Fano, E. A.; Mistri, M.; Rossi, R.

    2003-03-01

    A multimetric index for the evaluation of environmental quality (the ecofunctional quality index, EQI) has been developed using biotic data from three Italian coastal lagoons. Sampling programs were conducted between 1998 and 2000, on a yearly basis, with seasonal frequency at diverse sites in each lagoon. The rationale of the index is that certain attributes, selected on the basis of established principles of benthic ecology, are fundamental for lagoon ecosystem function. The chosen attributes were primary productivity, expressed as phytoplankton, seaweed and seagrass biomasses; structure and productivity of the benthic community, expressed as numerical abundance, biomass density, number of species, and taxonomic diversity of macrozoobenthos; and finally, trophic complexity, expressed as macrozoobenthic functional diversity. The EQI is constituted by the sum of weights given to these eight attributes, each transformed onto a dimensionless 0-100 quality scale. In this way, the use of EQI can derive a series of values yielding a 'functional classification' of sites within a lagoon or between different lagoons. The proposed index is a low cost, flexible and robust routine indicator of lagoon ecosystem impairment and could be of particular benefit to environmental managers and policymakers who require tools capable of expressing the degree of degradation or environmental quality of different lagoon habitats. The process of developing and the initial testing of EQI reported in this paper is intended as preliminary, and until validation of this index is accomplished by incorporating data from a wider range of lagoon environments, we caution the use of this index in anything other than an exploratory manner.

  18. CISOCUR - Residence time modelling in the Curonian Lagoon and validation through stable isotope measurements

    Science.gov (United States)

    Umgiesser, Georg; Razinkovas-Baziukas, Arturas; Zemlys, Petras; Ertürk, Ali; Mėžinė, Jovita

    2015-04-01

    The spatial pattern of the hydrodynamic circulation of the Curonian lagoon, the largest European coastal lagoon, is still little understood. In absence of automatic current registration data all the existing models relied mostly on such data as water levels leaving high level of uncertainty. Here we present CISOCUR, a new project financed by European Social Fund under the Global Grant measure. The project applies a new methodology that uses the carbon stable isotope (SI) ratio of C12 and C13 that characterize different water sources entering the lagoon and may be altered by internal kinetic processes. Through the tracing of these isotope ratios different water masses can be identified. This gives the possibility to validate several hypotheses of water circulation and validate hydrodynamic models. In particular it will be possible to 1) trace water masses entering the lagoon through the Nemunas and the Klaipeda strait; 2) test the hypothesis of sediment transport mechanisms inside the lagoon; 3) evaluate the importance of physical forcing on the lagoon circulation. The use of a hydrodynamic finite element model, coupled with the SI method, will allow for a realistic description of the transport processes inside the Curonian lagoon. So the main research goal is to apply the stable isotope tracers and a finite element model to determine the circulation patterns in the Curonian lagoon. Here we show how the SI analysis was used to validate the hydrodynamic model on the basis of residence time. The average residence time of the Nemunas waters is estimated through SI data and is then compared with the model data computed through standard algorithms. Seasonal changes of carbon content are taken care of through a preliminary application of a carbon kinetic model. The results are compared to literature data.

  19. Distribution and ecological relevance of fine sediments in organic-enriched lagoons: The case study of the Cabras lagoon (Sardinia, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Magni, P. [CNR-IAMC, National Research Council - Institute for Coastal Marine Environment Localita Sa Mardini, Torregrande, 09072 Oristano (Italy); International Marine Centre, Localita Sa Mardini, Torregrande, 09072 Oristano (Italy)], E-mail: paolo.magni@iamc.cnr.it; De Falco, G. [CNR-IAMC, National Research Council - Institute for Coastal Marine Environment Localita Sa Mardini, Torregrande, 09072 Oristano (Italy); International Marine Centre, Localita Sa Mardini, Torregrande, 09072 Oristano (Italy); Como, S. [International Marine Centre, Localita Sa Mardini, Torregrande, 09072 Oristano (Italy); Casu, D. [Dip. di Botanica ed Ecologia vegetale, Universita di Sassari, 07100 Sassari (Italy); Floris, A. [Dip. di Zoologia e Genetica evoluzionistica, Universita di Sassari, 07100 Sassari (Italy); Petrov, A.N. [Institute of Biology of the Southern Seas NASU, 99011 Sevastopol (Ukraine); Castelli, A. [Dip. di Biologia, Universita di Pisa, 56126 Pisa (Italy); Perilli, A. [CNR-IAMC, National Research Council - Institute for Coastal Marine Environment Localita Sa Mardini, Torregrande, 09072 Oristano (Italy); International Marine Centre, Localita Sa Mardini, Torregrande, 09072 Oristano (Italy)

    2008-03-15

    In organic-enriched sedimentary systems, like many Mediterranean coastal lagoons, a detailed analysis of sediment grain size composition and partitioning within the muds is crucial to investigate sedimentological trends related to both hydrodynamic energy and basin morphology. In these systems, sediment dynamics are particularly important because the partitioning and transport of fine sediments can strongly influence the redistribution and accumulation of large amounts of organic matter, and consequently the distribution of benthic assemblages and the trophic status and functioning of a lagoon. Nevertheless, studies on benthic-sediment relationships have been based mainly on a rather coarse analysis of sediment grain size features. In muddy systems, however, this approach may impede a proper evaluation of the relationships and effects of the distribution of fine sediment and organic matter on the biotic benthic components. Here we show that the distribution of sedimentary organic matter (OM) and total organic carbon (TOC) in the Cabras lagoon (Sardinia, Italy) can be explained (i.e., predicted) as a function of a nonlinear increase in the amount of the cohesive fraction of sediments ({<=}8 {mu}m grain size particles) and that this fraction strongly influences the structure, composition and distribution of macrobenthic assemblages. Even in such a homogeneously muddy system, characterized by 'naturally' occurring impoverished communities, impaired benthic assemblages were found at {<=}8 {mu}m, OM, TOC contents of about 77%, 11% and 3.5%, respectively. A review of studies conducted in Mediterranean coastal lagoons highlighted a lack of direct integrated analysis of sediment features and the biotic components. We suggest that, especially in organic-enriched coastal lagoons, monitoring programs should primarily investigate and consider the cohesive fraction of sediments in order to allow a better assessment of benthic-sediment relationships and ecological

  20. ( Sarotherodon Melanotheron ) from Lagos Lagoon

    African Journals Online (AJOL)

    The increases in industrial activities and rapid urban development which occur along the shores of the lagoon have resulted in serious pollution problems. The release of wastes containing hazardous substances and dumping of waste indiscriminately into water bodies could lead to environmental disturbance that might be ...

  1. Communicating climate risks to Vietnam's vulnerable coastal ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2015-05-04

    May 4, 2015 ... Game theory approaches were used to communicate with policymakers and city planners, and song writing and flash mob competitions were used to engage schoolchildren. The largest focus involved communication with households, typically the most difficult to reach. Short videos featuring local ...

  2. Aquatic macrophytes drive sediment stoichiometry and the suspended particulate organic carbon composition of a tropical coastal lagoon Macrófitas aquáticas determinam a estequiometria do sedimento e a composição do carbono orgânico particulado em suspensão de uma lagoa costeira tropical

    Directory of Open Access Journals (Sweden)

    Cláudio Cardoso Marinho

    2010-06-01

    Full Text Available AIM: This research aimed to evaluate (1 the influence of the aquatic macrophytes Typha domingensis Pers., Eleocharis interstincta (Vahl Roem. & Schult. (emergent and Potamogeton stenostachys K. Schum. (submersed on sediment stoichiometry and (2 the contribution of these aquatic macrophytes to organic carbon composition in different compartments of a tropical coastal lagoon (Cabiúnas Lagoon, Macaé-RJ; METHODS: The concentration of carbon (C, nitrogen (N and phosphorus (P was determined in 2-cm intervals in the first 10 cm of sediment in both littoral and limnetic regions. In the littoral region, the sediment was collected in three different sites: T. domingensis, E. interstincta and P. stenostachys stands. In order to know the pathways of C in Cabiunas lagoon, the isotopic signature (δ13C of restinga terrestrial vegetation, zooplankton, phytoplankton, macrophytes, dissolved and suspended material on water were evaluated; RESULTS: The concentrations of C and N in the sediment of the E. interstincta and T. domingensis stands were significantly higher than in the sediment of the limnetic region. The concentration of phosphorus in the sediment colonized by T. domingensis was higher than in the limnetic region and in P. stenostachys stand. The highest molar C:P ratios were found in E. interstincta and P. stenostachys stands. The highest N:P ratios were also found in the littoral region. Carbon stable isotopic analysis (δ13C signatures showed that a majority of the particulate organic carbon (POC in the water column had aquatic macrophyte tissues origin; CONCLUSIONS: Emergent macrophytes strongly contribute to nutrient enrichment of the sediment of Cabiúnas lagoon. In general, macrophyte detritus alters the littoral region sediment stoichiometry and quality for decomposers, by accumulating much more C in relation to N and P when compared to limnetic region. However, macrophytes importance isn't restricted to the sediment once they have a central

  3. Attempted suicide in Vietnam

    OpenAIRE

    Tran Thi Thanh, Huong

    2006-01-01

    Suicide and attempted suicide is currently a major public health problem in rapidly developing countries but there are limited studies on this field in Asian countries. These are the first studies on suicidal behavior in Vietnam. The aim of the studies was to: 1) investigate the prevalence of suicide attempts, plans, ideation and medical attention following a suicide attempt in Vietnam and in nine other countries, 2) investigate the relation between lifetime suicidal tho...

  4. Effect of climate change and mollusc invasion on eutrophication and algae blooms in the lagoon ecosystems of the Baltic Sea

    Science.gov (United States)

    Aleksandrov, Sergei; Gorbunova, Julia; Rudinskaya, Lilia

    2015-04-01

    Coastal lagoons are most vulnerable to impacts of natural environmental and anthropogenic factors. The Curonian Lagoon and Vistula Lagoon are the largest coastal lagoons of the Baltic Sea, relating to the most highly productive water bodies of Europe. The Curonian Lagoon is choke mostly freshwater lagoon, while the Vistula Lagoon is restricted brackish water lagoon. In the last decades the nutrients loading changes, warming trend and biological invasions are observed. The researches (chlorophyll, primary production, nutrients, phytoplankton, benthos, etc) were carried out monthly since 1991 to 2014. The database includes 1600 stations in the Curonian Lagoon, 1650 stations in the Vistula Lagoon. Eutrophication and algae blooms are most important problems. Multiple reductions of nutrients loading from the watershed area in 1990s did not result in considerable improvement of the ecological situation in the lagoons. The Curonian Lagoon may be characterized as hypertrophic water body with "poor" water quality. Climate change in 1990s-2000s combined with other factors (freshwater, slow-flow exchange, high nutrients concentrations) creates conditions for Cyanobacteria "hyperblooms". Hyperbloom of Cyanophyta (average for the growing season Chl > 100 μg/l) were observed during 4 years in 1990s and 7 years in 2000s. The summer water temperature is the key environmental factor determining the seasonal and long-term variability of the primary production and algae blooms. Mean annual primary production in 2010-2014 (600 gC·m-2·year-1) is considerable higher, than in the middle of 1970s (300 gC·m-2·year-1). The local climate warming in the Baltic region caused ongoing eutrophication and harmful algae blooms in the Curonian Lagoon despite of significant reduction of nutrients loading in 1990s-2000s. Harmful algal blooms in July-October (chlorophyll to 700-3400 μg/l) result in deterioration of the water chemical parameters, death of fish in the coastal zone and pollution

  5. Growth and mortality of Sphoeroides testudineus (Tetraodontiformes: Tetraodontidae in a tropical coastal lagoon in northwestern Yucatán Peninsula Crecimiento y mortalidad de Sphoeroides testudineus (Tetraodontiformes: Tetraodontidae en una laguna costera tropical en el noroeste de la península de Yucatán

    Directory of Open Access Journals (Sweden)

    José Luis Bonilla-Gómez

    2012-12-01

    Full Text Available This study reports growth parameters and mortality for Sphoeroides testudineus from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatán Peninsula, Mexico. A total of 461 specimens were collected between April 2009 and March 2010. We obtained the length-weight relationship and the growth parameters of von Bertalanffy growth model (VBGM by length frequency analysis. Additionally, mortality was estimated and analyzed. Exponent b indicated an isometric growth pattern. The growth parameters of VBGM were: L∞ = 29.50 cm, k= 0.77 year-1 and t0= - 0.168 years. The instantaneous natural mortality was 1.53 year-1.Este estudio reporta parámetros de crecimiento y mortalidad para Sphoeroides testudineus de La Carbonera, una laguna costera cárstica tropical en la costa noroeste de la península de Yucatán, México. Un total de 461 ejemplares se recogieron entre abril de 2009 y marzo de 2010. Se obtuvo la relación talla-peso y los parámetros de la ecuación de crecimiento de von Bertalanffy mediante el análisis de la frecuencia de tallas. Adicionalmente, se estimó y analizó la mortalidad. El exponente b indicó un patrón de crecimiento isométrico todo el año. Los parámetros del modelo de la ecuación de crecimiento de von Bertalanffy fueron: L∞ = 29.50 cm, k= 0.77 año-1 y t0= - 0.168 años. La mortalidad natural instantánea fue 1.53 año-1.

  6. Wind and freshwater influence over hydrocarbon dispersal on Patos Lagoon, Brazil.

    Science.gov (United States)

    Janeiro, João; Fernandes, Elisa; Martins, Flávio; Fernandes, Rodrigo

    2008-04-01

    The two-dimensional barotropic, hydrodynamic and transport model MOHID is applied to the Patos Lagoon system using a nested modelling approach to reproduce both the lagoon and estuary hydrodynamics. A new Lagrangian oil spill model is presented and used to simulate a hypothetical oil spill in the estuary. Hydrodynamic fields are validated and used to force the oil model. Results show that the hydrodynamics of this system is mainly controlled by the wind and freshwater discharge. The dispersion, concentration and thickness evolution of the oil in the first day after the spill is determined by the equilibrium between these two factors. The freshwater discharge is the major factor controlling the oil dispersion for discharges greater than 5000 m3 while the wind assumes control for lower discharge amounts. The results presented are a first step toward a coastal management tool for the Patos Lagoon.

  7. Identification of pollution of Tapeng Lagoon from neighbouring rivers using multivariate statistical method.

    Science.gov (United States)

    Liao, Shao-Wei; Gau, Hwa-Sheng; Lai, Wen-Liang; Chen, Jen-Jeng; Lee, Chang-Gai

    2008-07-01

    This work investigated water samples collected from Tapeng Lagoon and three neighbouring rivers (the Kaoping River, Tungkang River and Lingbeng River) in Taiwan, Republic of China. Canonical discriminant analysis was applied to identify the source of pollution in neighbouring rivers outside Tapeng Lagoon. The two constructed discriminant functions showed a marked contribution to all discriminant variables, and the total nitrogen, algae, dissolved oxygen and total phosphate were combined as the nutrient effect factor. The recognition capacities of the two discriminant functions were 95.6% and 4.4%, respectively. The water quality in the Kaoping River most strongly controlled the water quality in Tapeng Lagoon. Disassembling the oyster frames and fishery boxes had improved the water quality markedly. The methodology and results provide useful information concerning watershed management and may be applicable to other basins with similar properties that are experiencing similar coastal environmental issues.

  8. On an extremely dense bloom of the dinoflagellate Alexandrium tamarense in lagoons of the PO river delta: Impact on the environment

    Science.gov (United States)

    Sorokin, Yu. I.; Sorokin, P. Yu.; Ravagnan, G.

    1996-06-01

    An extremely dense bloom of the potentially toxic dinoflagellate Alexandrium tamarense was observed in the lagoons of Cà Pisani (Veneto, Italy) in summer 1993. The lagoons were experiencing a significant eutrophication impact, receiving waste waters from intensive fish culture plants. During their bloom dinoflagellates in the lagoons reached densities of 2 to 4 × 10 6 cells·dm -3 and a biomass of over 100 g·m -3. The bloom produced drastic ecological changes in the lagoons. It caused nocturnal anoxia, mortality of macrophytes and the build-up of labile organic matter in the water column. Grazing by the tintinnid Favella sp. contributed to the termination of the bloom of the flagellates. The results show that coastal aqua culture probably stimulates dinoflagellate blooms in shallow brackish lagoons.

  9. A new model evaluating Holocene sediment dynamics: Insights from a mixed carbonate-siliciclastic lagoon (Bora Bora, Society Islands, French Polynesia, South Pacific)

    Science.gov (United States)

    Isaack, Anja; Gischler, Eberhard; Hudson, J. Harold; Anselmetti, Flavio S.; Lohner, Andreas; Vogel, Hendrik; Garbode, Eva; Camoin, Gilbert F.

    2016-08-01

    Mixed carbonate-siliciclastic lagoons of barrier reefs provide great potential as sedimentary archives focusing on paleoenvironmental and paleoclimatic changes as well as on event deposition. Sediment sources include lagoonal carbonate production, the marginal reef and the volcanic hinterland. Mixed carbonate-siliciclastic continent-attached coastal lagoons have been intensively studied, however, their isolated oceanic counterparts have been widely disregarded. Here, we present a new model of Holocene sediment dynamics in the barrier-reef lagoon of Bora Bora based on sedimentological, paleontological, geochronological and geochemical data. The lagoonal succession started with a Pleistocene soil representing the Lowstand Systems Tract. As the rising Holocene sea inundated the carbonate platform, peat accumulated locally 10,650-9400 years BP. Mixed carbonate-siliciclastic sedimentation started ca. 8700-5500 years BP and represents the Transgressive Systems Tract. During that time, sediments were characterized by relatively coarse grain size and contained high amounts of terrestrial material from the volcanic hinterland as well as carbonate sediments mainly produced within the lagoon. Siliciclastic content decreases throughout the Holocene. After the rising sea had reached its modern level, sand aprons formed between reef crest and lagoon creating transport pathways for reef-derived material leading to carbonate-dominated sedimentation ca. 6000-3000 years BP during the Highstand Systems Tract. However, mainly fine material was transported and accumulated in the lagoon while coarser grains were retained on the prograding sand apron. From ca. 4500-500 years BP, significant variations in grain-size, total organic carbon as indicator for primary productivity, Ca and Cl element intensities as qualitative indicators for carbonate availability and lagoonal salinity are seen. Such patterns could indicate event (re-)deposition and correlate with contemporaneous event deposits

  10. CASE STUDY: Vietnam — Information brings progress to Vietnam's ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-12-16

    CASE STUDY: Vietnam — Information brings progress to Vietnam's communes. December 16, 2010. Image. Michelle Hibler. In Vietnam, a .... The strategy, he says, is to concentrate assistance on vulnerable groups, like women-headed households, widows, and invalids. There are 41 such deprived households in Gia Son.

  11. Essays on economic valuation of cultural and natural resources in Vietnam

    OpenAIRE

    Tuan, Tran Huu

    2007-01-01

    The thesis consists of five self-contained papers. The first four papers are concerned with the economic valuation of cultural heritage sites, while the last one estimates direct use values of coastal wetlands in Vietnam. In the first paper, contingent valuation is used to estimate the economic benefits of preserving the world cultural heritage site of My Son temples in Vietnam, and shows how these benefits can be captured and used to justify investments in preservation of this site. Th...

  12. Hydrogeological effects of dredging navigable canals through lagoon shallows. A case study in Venice

    Directory of Open Access Journals (Sweden)

    P. Teatini

    2017-11-01

    Full Text Available For the first time a comprehensive investigation has been carried out to quantify the possible effects of dredging a navigable canal on the hydrogeological system underlying a coastal lagoon. The study is focused on the Venice Lagoon, Italy, where the port authority is planning to open a new 10 m deep and 3 km long canal to connect the city passenger terminal to the central lagoon inlet, thus avoiding the passage of large cruise ships through the historic center of Venice. A modeling study has been developed to evaluate the short (minutes, medium (months, and long (decades term processes of water and pollutant exchange between the shallow aquifer system and the lagoon, possibly enhanced by the canal excavation, and ship wakes. An in-depth characterization of the lagoon subsurface along the channel has supported the numerical modeling. Piezometer and sea level records, geophysical acquisitions, laboratory analyses of groundwater and sediment samples (chemical analyses and ecotoxicity testing, and the outcome of 3-D hydrodynamic and computational fluid dynamic (CFD models have been used to set up and calibrate the subsurface multi-model approach. The numerical outcomes allow us to quantify the groundwater volume and estimate the mass of anthropogenic contaminants (As, Cd, Cu, Cr, Hg, Pb, Se likely leaked from the nearby industrial area over the past decades, and released into the lagoon from the canal bed by the action of depression waves generated by ships. Moreover, the model outcomes help to understand the effect of the hydrogeological layering on the propagation of the tidal fluctuation and salt concentration into the shallow brackish aquifers underlying the lagoon bottom.

  13. Development of Alternatives to Mitigate Deterioration of Segara Anakan Lagoon as Revealed by Analytical Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Harnita Rosalina

    2016-09-01

    Full Text Available Segara Anakan is a lagoon located in estuary area of Citanduy and Cibeureum rivers. The main problem that exists in the region Segara Anakan is a shrinking area of Segara Anakan lead lagoon function becomes ineffective due to the increased volume of sediment in estuaries Citanduy. Refinement Segara Anakan will impact annual floods that occurred in the area downstream Citanduy. Have far-reaching is the decline in fish production, which makes the source of livelihood for the community residents of Kampung Laut, furthermore, the environmental changes that occurred in the area Segara Anakan have resulted in shrinking coastal fisheries resources and the expansion of land arising from silting. Assessment of the problem conducted by the method of approach of Analytical Hierarchy Process(AHP to obtain the best alternatives among three alternatives being offered to sustain the function of Segara Anakan Lagoon. These three alternatives include the 1 Dredging the Lagoon and Upstream Watershed Conservation; 2 Dredging the Lagoon and Reclamation Work around Segara Anakan, and 3 Dredging the Lagoon and Citanduy Diversion. Some criteria and sub-criteria are adapted to support the selection of the alternatives and related questionnaires were developed, and the questionnaire filling was carried out through the implementation of Focus Group of Discussion or FGD. The criteria include several aspects of the criteria and sub-criteria are technical (floods, silting, socioeconomic (the tourist area, the local economy, as well as the environment (fisheries/shipping, agriculture and mangrove forests. Results of the analysis applying the AHP method showed the consistent value on the Alternative 3, i.e. the Dredging of the Lagoon and the Upstream Watershed Conservation (38%.

  14. Corporate Governance Country Assessment : Vietnam

    OpenAIRE

    World Bank

    2013-01-01

    This report assesses Vietnam's corporate governance policy framework. It highlights recent improvements in corporate governance regulation, makes policy recommendations, and provides investors with a benchmark against which to measure corporate governance in Vietnam. It is an update of the 2006 Corporate Governance ROSC for Vietnam. Good corporate governance enhances investor trust, protec...

  15. Hydrodynamics, temperature/salinity variability and residence time in the Chilika lagoon during dry and wet period: Measurement and modeling

    Science.gov (United States)

    Mahanty, M. M.; Mohanty, P. K.; Pattnaik, A. K.; Panda, U. S.; Pradhan, S.; Samal, R. N.

    2016-08-01

    This paper investigated the hydrodynamics, spatio-temporal variability of temperature/salinity and the residence time of tracer concentrations in a largest brackish water coastal lagoon in Asia, namely the Chilika lagoon, India. An integrated approach combined the measurement and 2D hydrodynamic-advection/dispersion model is used to simulate circulation and temperature/salinity, and estimated the water residence time in lagoon under different forcing mechanisms, such as tide, wind and freshwater discharge during the dry and wet periods. Water circulation inside the lagoon is simulated when wind is included with the tide only forcing during dry period, and freshwater influx is included with the tide and wind forcing during wet period. Under the realistic forcing conditions, the computed temporal variability of water temperature and salinity are well correlated with the measurements in both the periods. The spatial variations of water temperature within the lagoon is influenced by the meteorological conditions, tide and freshwater influx as well as the shallowness of the lagoon, whereas the salinity is spatially controlled by the freshwater influx from the riverine system and seawater intrusion through the tidal inlets. The numerical model results show that in the Chilika lagoon tidal and river influx affect significantly the residence time spatially, and is site specific. The residence time varies from values of 4-5 days in the outer channel (OC) and 132 days at the northern sector (NS) in the main body of lagoon. The current study represents a first attempt to use a combined model approach, which is therefore, a useful tool to support the ecological implication of the lagoon ecosystem.

  16. CISOCUR - Hydrodynamic circulation in the Curonian Lagoon inferred through stable isotope measurements and numerical modelling

    Science.gov (United States)

    Umgiesser, Georg; Razinkovas-Baziukas, Arturas; Barisevičiūtė, Ruta; Baziukė, Dalia; Ertürk, Ali; Gasiūnaitė, Jovita; Gulbinskas, Saulius; Lubienė, Irma; Maračkinaite, Jurgita; Petkuvienė, Jolita; Pilkaitytė, Renata; Ruginis, Tomas; Zemlys, Petras; Žilius, Mindaugas

    2013-04-01

    The spatial pattern of the hydrodynamic circulation of the Curonian lagoon, the largest European coastal lagoon, is still little understood. In absence of automatic current registration data all the existing models relied mostly on such data as water levels leaving high level of uncertainty. Here we present CISOCUR, a new project financed by the European Social Fund under the Global Grant measure. The project applies a new methodology that uses the carbon stable isotope (SI) ratio of C12 and C13 that characterize different water sources entering the lagoon and may be altered by internal kinetic processes. Through the tracing of these isotope ratios different water masses can be identified. This gives the possibility to validate several hypotheses of water circulation and validate hydrodynamic models. In particular it will be possible to 1) trace water masses entering the lagoon through the Nemunas and the Klaipeda strait; 2) test the hypothesis of sediment transport mechanisms inside the lagoon; 3) evaluate the importance of physical forcing on the lagoon circulation. The use of a hydrodynamic finite element model, coupled with the SI method, will allow for a realistic description of the transport processes inside the Curonian lagoon. So the main research goal is to apply the stable isotope tracers and a finite element model to determine the circulation patterns in the Curonian lagoon. Overall, the project will develop according to 4 main phases: 1) A pilot study to measure the isotope composition of different carbon compounds (dissolved and suspended) in different water bodies that feed water into the central lagoon. Through this pilot study the optimal study sites for the seasonal campaign will be identified as well. 2) Seasonal field campaigns in the monitoring stations identified in phase 1 to measure the carbon isotope ratio. 3) Development of a model that describes the kinetics of carbon isotopes and its transformation. 4) Application of a hydrodynamic model

  17. Lagoonal stormwater detention ponds as promoters of harmful algal blooms and eutrophication along the South Carolina coast

    Science.gov (United States)

    Alan J. Lewitus; Larissa M. Brock; Marianne K. Burke; Krista A. DeMattio; Susan B. Wilde

    2008-01-01

    In the rapidly urbanizing coastal zone of South Carolina, intensive landscape maintenance and turf management are significant sources of nonpoint source pollutant loadings. The best management practice of choice for stormwater in this region is wet detention ponds, the majority of which are brackish lagoons. Typically, stormwater is piped directly into the ponds, but...

  18. Diabetes in Vietnam.

    Science.gov (United States)

    Khue, Nguyen Thy

    2015-01-01

    The prevalence for diabetes, prediabetes, and gestational diabetes in Vietnam are low relative to other parts of the world, but they are increasing at alarming rates. These changes have occurred in the setting of economic and cultural transitions. The aim of this study was to provide relevant information depicting the diabetes burden in Vietnam. Literature was reviewed using PubMed and local Vietnamese sources, including papers published in the Vietnamese language. In 2012, the prevalence of diabetes was 5.4% and prediabetes 13.7%. In 2005, the prevalence of obesity was 1.7%. There is a dual burden of over- and undernutrition observed in Vietnam. Diabetes is associated with an increased waist-to-hip ratio despite normal body mass index. Nutritional transitions occurred with increased protein, fat, and fast foods, and with decreased fresh fruits and vegetables. Tobacco use is very high in Vietnam with 66% of adult men currently smoking. Challenges include endocrinology training, health care coverage, patient education, and lack of coordination among government and specialist agencies. Diabetes is a growing problem in Vietnam and is associated with obesity, changes in dietary patterns, and other cultural transitions. More research is needed to better understand this health care problem and to devise targeted interventions. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  19. EU and Vietnam

    DEFF Research Database (Denmark)

    Kokko, Ari

    This paper discusses the changing relationship between the EU and Vietnam, and asks whether there is a shift from a “parental” to a “competitive” relationship. The focus of the paper is on the shift from aid to trade as the main interface between the EU and Vietnam. Aid relationships are often...... understood as hierarchical, linking a benevolent donor to a needy recipient, whereas commercial relationships are typically expected to involve a more competitive relationship. However, we argue that the bilateral relationship was never a “parental” one, even at the time when Vietnam’s relation to the EU...... was limited to aid. The reason is largely Vietnam’s historical experiences from the aid relationship with the Soviet Union, which created dependence and eventually an economic crisis when aid flows dried up in the late 1980s. Instead, there has been substantial tension between the donor community and Vietnam...

  20. Biodiversity patterns of macrophyte and macroinvertebrate communities in two lagoons of Western Greece.

    Science.gov (United States)

    Fyttis, G.; Reizopoulou, S.; Papastergiadou, E.

    2012-04-01

    Aquatic macrophytes and benthic macroinvertebrates were studied seasonally (Spring, Autumn, Summer) between the years 2009 - 2011 in two coastal lagoons (Kotychi and Prokopos) located in Peloponnese, Greece, in order to investigate spatial and temporal biodiversity trends related to hydrological processes (degree of confinement, nitrates, phosphates, chl-a, total suspended materials, light irradiance, pH, salinity, temperature and dissolved oxygen). Kotychi lagoon presents a better communication with the sea, while Prokopos has a high degree of confinement. Both ecosystems seasonally receive freshwater input from streams. The submerged aquatic macrophytes constituted a major component of the ecosystems studied. In total, 22 taxa of aquatic macrophytes (angiosperms and macroalgae), 16 taxa for Kotychi (2 Rhodophyta, 8 Chlorophyta, 5 Magnoliophyta, 1 Streptophyta) and 14 taxa for Prokopos (1 Rhodophyta, 5 Chlorophyta, 5 Magnoliophyta, 3 Streptophyta) were found. Ruppia cirrhosa, and Potamogeton pectinatus were dominant in both lagoons. Kotychi lagoon was also dominated by Zostera noltii and Prokopos by Zannichellia pallustris ssp. pedicellata, while the biomass of aquatic species peaked during the summer periods, in both lagoons. The total number of macroinvertebrates found in the lagoons was 28 taxa for Kotychi and 19 for Prokopos. Chironomidae were dominant in both lagoons, while Kotychi was also dominated by Lekanesphaera monodi and Monocorophium insidiosum, and Prokopos by Ostracoda and Lekanesphaera monodi. Benthic diversity ranged from 1.33 to 2.57 in Kotychi and from 0.67 to 2.48 in Prokopos. Species richness, diversity, and abundance of benthic macroinvertebrates were strongly related to aquatic vegetation and to the degree of communication with the marine environment. Moreover, species richness and abundance of both macrophytes and macroinvertebrates were mainly dependent on depth, temperature, pH and concentration of total suspended materials (TSM). Results

  1. VIETNAM: 'N BLOEDIGE LEERSKOOL

    African Journals Online (AJOL)

    30 Apr 1975 ... The Republic of South Vietnam collapsed in a heap of chaos, and brought to an end a war that spanned three decades. It was also the United. States of America's first major defeat. This article provides insight into the reasons for the defeat. Inleiding. Die onvoorwaardelike oorgawe van Suid-Viet- nam op 30 ...

  2. IDRC in Vietnam

    International Development Research Centre (IDRC) Digital Library (Canada)

    , began offering Internet and e-mail. Netnam thrives to this day as a private company run by the original. IDRC-supported team. In the early 2000s, Vietnam's Fisheries. College No. 4 and Canada's College of the North Atlantic created the ...

  3. IDRC in Vietnam

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRCinternAtionAl DeveloPMent reSeArCh Centre. IDRC in Vietnam. IDRC support is helping: □ Disadvantaged groups, including women, access natural resources. □ Migrant women protect their rights. □ Small poultry producers reduce risk under new bird flu controls. □ Farmers find alternatives to growing tobacco.

  4. Rural Credit in Vietnam

    DEFF Research Database (Denmark)

    Barslund, Mikkel Christoffer; Tarp, Finn

    This paper uses a survey of 932 rural households to uncover how the rural credit market operates in four provinces of Vietnam. Households obtain credit through formal and informal lenders, but formal loans are almost entirely for production and asset accumulation. Interest rates fell from 1997...

  5. Doing Business in Vietnam

    DEFF Research Database (Denmark)

    Meyer, Klaus E.; Tran, Thi Thu Yen; Nguyen, Hung Vo

    2005-01-01

    Over the last thirty years, Vietnam evolved from `war after war' to an emerging economy with an attractive foreign investment policy and commitment to a liberalized economy. Although the GDP per capita is still considerably lower than in the Asian Tiger economies, and the institutional framework...

  6. State-of-the-lagoon reports as vehicles of cross-disciplinary integration.

    Science.gov (United States)

    Zaucha, Jacek; Davoudi, Simin; Slob, Adriaan; Bouma, Geiske; van Meerkerk, Ingmar; Oen, Amy Mp; Breedveld, Gijs D

    2016-10-01

    An integrative approach across disciplines is needed for sustainable lagoon and estuary management as identified by integrated coastal zone management. The ARCH research project (Architecture and roadmap to manage multiple pressures on lagoons) has taken initial steps to overcome the boundaries between disciplines and focus on cross-disciplinary integration by addressing the driving forces, challenges, and problems at various case study sites. A model was developed as a boundary-spanning activity to produce joint knowledge and understanding. The backbone of the model is formed by the interaction between the natural and human systems, including economy and governance-based subsystems. The model was used to create state-of-the-lagoon reports for 10 case study sites (lagoons and estuarine coastal areas), with a geographical distribution covering all major seas surrounding Europe. The reports functioned as boundary objects to build joint knowledge. The experiences related to the framing of the model and its subsequent implementation at the case study sites have resulted in key recommendations on how to address the challenges of cross-disciplinary work required for the proper management of complex social-ecological systems such as lagoons, estuarine areas, and other land-sea regions. Cross-disciplinary integration is initially resource intensive and time consuming; one should set aside the required resources and invest efforts at the forefront. It is crucial to create engagement among the group of researchers by focusing on a joint, appealing overall concept that will stimulate cross-sectoral thinking and focusing on the identified problems as a link between collected evidence and future management needs. Different methods for collecting evidence should be applied including both quantitative (jointly agreed indicators) and qualitative (narratives) information. Cross-disciplinary integration is facilitated by functional boundary objects. Integration offers important

  7. Chasing boundaries and cascade effects in a coupled barrier-marsh-lagoon system

    Science.gov (United States)

    Lorenzo-Trueba, Jorge; Mariotti, Giulio

    2017-08-01

    The long-term dynamic evolution of an idealized barrier-marsh-lagoon system experiencing sea-level rise is studied by coupling two existing numerical models. The barrier model accounts for the interaction between shoreface dynamics and overwash flux, which allows the occurrence of barrier drowning. The marsh-lagoon model includes both a backbarrier marsh and an interior marsh, and accounts for the modification of the wave regime associated with changes in lagoon width and depth. Overwash, the key process that connects the barrier shoreface with the marsh-lagoon ecosystems, is formulated to account for the role of the backbarrier marsh. Model results show that a number of factors that are not typically associated with the dynamics of coastal barriers can enhance the rate of overwash-driven landward migration by increasing backbarrier accommodation space. For instance, lagoon deepening could be triggered by marsh edge retreat and consequent export of fine sediment via tidal dispersion, as well as by an expansion of inland marshes and consequent increase in accommodation space to be filled in with sediment. A deeper lagoon results in a larger fraction of sediment overwash being subaqueous, which coupled with a slow shoreface response sending sediment onshore can trigger barrier drowning. We therefore conclude that the supply of fine sediments to the back-barrier and the dynamics of both the interior and backbarrier marsh can be essential for maintaining the barrier system under elevated rates of sea-level rise. Our results highlight the importance of considering barriers and their associated backbarriers as part of an integrated system in which sediment is exchanged.

  8. Food web structure of two Mediterranean lagoons under varying degree of eutrophication

    Science.gov (United States)

    Carlier, Antoine; Riera, Pascal; Amouroux, Jean-Michel; Bodiou, Jean-Yves; Desmalades, Martin; Grémare, Antoine

    2008-11-01

    The food web structure and functioning of two north-western Mediterranean lagoons exhibiting contrasting degrees of eutrophication and marine influences were compared through δ13C and δ15N analysis of major potential food sources and consumers. The Lapalme Lagoon is well preserved and has kept a natural and temporary connection with the open sea. Conversely, the Canet Lagoon is heavily eutrophicated and its water exchange with the open sea has been artificially reduced. In Lapalme, all potential food sources and consumers exhibited δ15N values indicative of pristine coastal areas. Suspended particulate organic matter (POM) and sediment organic matter (SOM) pools seemed to constitute the main food sources of most primary consumers. Both primary producers and all consumers were much more 15N-enriched (by ˜ 10‰) and more 13C-depleted in Canet than in Lapalme. This reflected: (1) the assimilation of important amounts of anthropogenic nitrogen in the food web, and (2) a marked and uniform influence of 13C-depleted allochtonous sources of carbon. Based on the mean δ15N of primary consumers, we found rather similar food web lengths in both lagoons with top consumers at trophic levels 3.6 and 4.0 in Canet and Lapalme, respectively. However, the eutrophication of the Canet Lagoon resulted in a simplification of the food web structure (i.e., a single trophic pathway from a 15N-enriched fraction of the SOM pool to top predators) compared to what was observed in Lapalme Lagoon where additional 13C-enriched food sources played a significant trophic role. Moreover, some consumers of Canet tended to exploit primary producers to a larger extent (and thus to exhibit lower trophic levels) than in Lapalme.

  9. Estuarine and lagoon biodiversity and their natural goods and services

    Science.gov (United States)

    Basset, A.; Elliott, M.; West, R. J.; Wilson, J. G.

    2013-11-01

    Assessing and monitoring ecosystem quality status and service provision of aquatic ecosystems is an increasingly important area of scientific, socio-economical and political interest. Contributions from two related meetings organized by the Estuarine & Coastal Sciences Association (ECSA) and the Euro-Mediterranean Lagoon Federation (EUROMEDLAG) address this area of interest in estuaries and lagoons, dominant types of transitional waters, by an integration of holistic and reductionistic approaches. In this context, we synthesise the key points raised by the contributions given at the two meetings to emphasise that transitional waters have emergent properties, which support their classification as an aquatic realm different from both freshwater and marine ones. They provide crucial ecosystem services, such as food provision and support for nutrient cycling, whose value and underlying mechanisms have been addressed with particular reference to estuarine ecosystems. The experimental studies show the mechanistic relationships and the responses of ecosystem functions and biodiversity to contrasting/changing environmental conditions with human activities as key drivers affecting both biodiversity conservation and ecosystem service provision.

  10. Tracer studies on an aerated lagoon.

    Science.gov (United States)

    Broughton, Alistair; Shilton, Andy

    2012-01-01

    The city of Palmerston North, New Zealand, has two aerated lagoons as its secondary treatment facility. Interest about treatment efficiency led to an investigation into the hydraulics in the second lagoon to determine if further optimisation was viable. A tracer study using rhodamine WT was undertaken to ascertain the stimulus response output. Samples were also taken at 24 points within the lagoon to determine the tracer concentration profile throughout the lagoon. The mean residence time was determined to be 39.9 h compared with a theoretical residence time of 55.4 h. Peak concentration of the tracer at the outlet occurred at 0.44 of the mean residence time. The results of the tracer study pointed to 28% of volume being dead space. A subsequent sludge survey indicated that 26% of the design volume of the lagoon was filled with sludge. While the curved geometry of the lagoon did not appear to impact the hydraulics the fact that the first aerator is confined in a relatively smaller area will have locally boosted the mixing energy input in this inlet zone. From interpretation of the tracer response and the tracer distribution profiles it appears that the aerators are mixing the influent into the bulk flow effectively in the front end of the lagoon and that there was no evidence of any substantive short-circuiting path of concentrated tracer around to the outlet. The tracer distribution profiles gave direct insight as to how the tracer was being transported within the pond and should be used more often when conducting tracer studies. Comparison with the literature indicated that the lagoon's hydraulic efficiency was on par with a baffled pond system and it would be expected that addition of several baffles to the lagoon would provide minimal further improvement.

  11. Sedimentation rate and lateral migration of tidal channels in the Lagoon of Venice (Northern Italy)

    Science.gov (United States)

    Donnici, Sandra; Madricardo, Fantina; Serandrei-Barbero, Rossana

    2017-11-01

    Tidal channels are crucial for the functioning of highly valuable coastal environments, such as estuaries and lagoons. Their properties, however, are currently less understood than those of river systems. To elucidate their past behaviour, an extensive geophysical investigation was performed to reconstruct the evolution of channels and tidal surfaces in the central part of the Lagoon of Venice (Italy) over the past 5000 years. Comparing high-spatial-resolution acoustic data and sedimentary facies analyses of 41 cores, 29 of which were radiocarbon dated, revealed the sedimentation rates in different lagoonal environments and allowed the migration of two large meanders to be reconstructed. The average sedimentation rate of the study succession in the different sedimentary environments was 1.27 mm yr-1. The lateral migration rates were 13-23 m/century. This estimate is consistent with the lateral migration rates determined by comparing aerial photographs of recent channels. Comparing the buried channels with historical and current maps showed that, in general, the number of active channels is now reduced. Their morphology was sometimes simplified by artificial interventions. An understanding of the impact of the artificial interventions over time is useful for the management and conservation of tidal environments, particularly for the Lagoon of Venice, where management authorities are currently debating the possible deepening and rectification of large navigation channels.

  12. Nitrogen enrichment and speciation in a coral reef lagoon driven by groundwater inputs of bird guano

    Science.gov (United States)

    McMahon, Ashly; Santos, Isaac R.

    2017-09-01

    While the influence of river inputs on coral reef biogeochemistry has been investigated, there is limited information on nutrient fluxes related to submarine groundwater discharge (SGD). Here, we investigate whether significant saline groundwater-derived nutrient inputs from bird guano drive coral reef photosynthesis and calcification off Heron Island (Great Barrier Reef, Australia). We used multiple experimental approaches including groundwater sampling, beach face transects, and detailed time series observations to assess the dynamics and speciation of groundwater nutrients as they travel across the island and discharge into the coral reef lagoon. Nitrogen speciation shifted from nitrate-dominated groundwater (>90% of total dissolved nitrogen) to a coral reef lagoon dominated by dissolved organic nitrogen (DON; ˜86%). There was a minimum input of nitrate of 2.1 mmol m-2 d-1 into the lagoon from tidally driven submarine groundwater discharge estimated from a radon mass balance model. An independent approach based on the enrichment of dissolved nutrients during isolation at low tide implied nitrate fluxes of 5.4 mmol m-2 d-1. A correlation was observed between nitrate and daytime net ecosystem production and calcification. We suggest that groundwater nutrients derived from bird guano may offer a significant addition to oligotrophic coral reef lagoons and fuel ecosystem productivity and the coastal carbon cycle near Heron Island. The large input of groundwater nutrients in Heron Island may serve as a natural ecological analogue to other coral reefs subject to large nutrient inputs from anthropogenic sources.

  13. Comparison of metal concentrations in tissues of blue crab, Callinectes sapidus from Mediterranean Lagoons.

    Science.gov (United States)

    Mutlu, Cengiz; Türkmen, Mustafa; Türkmen, Aysun; Tepe, Yalçın

    2011-09-01

    This study was performed to investigate the metal concentrations in muscle and gill of blue crab, Callinectes sapidus from Dörtyol Lake, Akyatan Lagoon, Paradeniz Lagoon and Çamlık Lagoon from the northeastern coastal area of Mediterranean Sea. So, the levels of cadmium, chromium, copper, iron, manganese, nickel, aluminum and zinc in tissues of specimens from the lagoons were determined by inductively coupled plasma optical emission spectrometer. The metal concentrations found in muscle tissue varied for Cd: 0.03-0.08, Cr: 0.05-0.13, Cu: 5.38-11.7, Fe: 21.1-38.2, Mn: 0.15-2.98, Ni: 0.24-0.45, Zn: 13.9-20.1 and Al: 1.2-13.7 mg/kg wet weight. Iron showed the highest levels in both tissues, and generally followed by zinc except gills. On the other hand, cadmium showed the lowest levels from all sites. Followed cadmium; chromium had the second lowest levels. The differences between mean metal concentrations from different sampling sites were statistically significant. Regional changes in metal concentration were observed in the tissues of the crabs, but these variations may not influence consumption advisories.

  14. Environmental Quality Assessment of Bizerte Lagoon (Tunisia Using Living Foraminifera Assemblages and a Multiproxy Approach.

    Directory of Open Access Journals (Sweden)

    Maria Virgínia Alves Martins

    Full Text Available This study investigated the environmental quality of the Bizerte Lagoon (Tunisia through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses. Specifically, we analyzed the physicochemical parameters of the water and sediment. The textural, mineralogical, and geochemical characteristics of the sediment, including total organic carbon, total nitrogen, simultaneously extracted metals (SEM, acid volatile sulfides (AVS, chlorophyll a, CaCO3, and changes in bacterial populations and carbon isotopes were measured. The SEM/AVS values indicated the presence of relatively high concentrations of toxic metals in only some areas. Foraminiferal assemblages were dominated by species such as A. parkinsoniana (20-91%, Bolivina striatula (<40%, Hopkinsina atlantica (<17%, and Bolivina ordinaria (<15% that cannot be considered typical of impacted coastal lagoons both in Mediterranean and northeast Atlantic regions. The results of this work suggest that Bizerte Lagoon is a unique setting. This lagoon is populated by typical marine species that invaded this ecosystem, attracted not only by the prevailing favorable environmental conditions but also by the abundance and quality of food. The results indicate that the metal pollution found in some areas have a negative impact on the assemblages of foraminifera. At present, however, this negative impact is not highly alarming.

  15. The Vietnam War

    DEFF Research Database (Denmark)

    Godbolt, James; Larsen, Chris Holmsted; Rasmussen, Søren Hein

    2009-01-01

    This article investigates the role of the Vietnam War in Danish and Norwegian politics. We argue that Danish and Norwegian membership in NATO and an unstable parliamentary situation may explain why these countries, unlike Sweden, did not take on the lead in the international protest against the war...... in Denmark, Sweden and Norway, and in all three countries powerful protest movements emerged that were remarkably similar. The Vietnam War strengthened the left in general and promoted a leftist politics of solidarity that influenced Swedish, Danish and Norwegian foreign policy-making of the 1970s........ Non-socialistic coalitions came to power in Norway and Denmark in the latter half of the 1960s which to an extent explains why the social democratic parties in both countries became more critical of the US. By the end of the 1960s, foreign policy as well as public attitudes towards the war converged...

  16. EPA GOMEX Wild Goose Lagoon 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We compared nekton use of prominent habitat types within a lagoonal system of the northeastern Gulf of Mexico (GoM). These habitat types were defined by combinations...

  17. Teaching in Vietnam

    CERN Multimedia

    Vitale,B

    1974-01-01

    Monsieur B.Vitale porte depuis plusieurs années un grand interêt aux questions d'enseignement dans les pays du tiers monde et a recemment eu l'occasion de faire un séjour dans la république démocratique du Vietnam. Il va nous faire part de ses impressions dans le domaine de l'enseignement, qu'il a vu, entrevu et essayé de comprendre

  18. DINAMIKA PERDAGANGAN BERAS VIETNAM

    OpenAIRE

    Nugroho, Agus Dwi; Jamhari, Jamhari; Mulyo, Jangkung Handoyo

    2017-01-01

    The aims of this study is to analyze the performance of export-import, competitiveness and the factors affecting export-import of Vietnam rice. Type of data used is secondary data of 1980-2009. To determine the fluctuation of export-import trade were applied trend and trade specialization ratio. To find out the analysis of competitiveness were run revealed comparative advantage (RCA) and acceleration ratio (AR). To investigate the factors affecting the export and import used error correction ...

  19. Characterisation of a Tunisian coastal lagoon through hyperspectral ...

    African Journals Online (AJOL)

    In situ hyperspectral irradiance was measured at several stations, from which the apparent optical properties (AOPs), namely the irradiance attenuation coefficient K(λ) and the reflectance ratio R(λ), were obtained in order to relate them to water composition, in terms of light-attenuating substances (LASs). The significant ...

  20. Macroinvertebrates communities of a coastal lagoon in southern ...

    African Journals Online (AJOL)

    Annelids and Insects were the second most predominant. This restricted biodiversity is based on a limited number of species such as Tympanotonus fuscatus radula, Pachymelania aurita, Neritina glabrata, Corbula sp., Clibanarius spp., Grandidierella africana, Nereis sp. and Chironomus sp.. Site typology based on ...

  1. Anthropogenic organic contaminants in water, sediments and benthic organisms of the mangrove-fringed Segara Anakan Lagoon, Java, Indonesia.

    Science.gov (United States)

    Dsikowitzky, Larissa; Nordhaus, Inga; Jennerjahn, Tim C; Khrycheva, Polina; Sivatharshan, Yoganathan; Yuwono, Edy; Schwarzbauer, Jan

    2011-04-01

    Segara Anakan, a mangrove-fringed coastal lagoon in Indonesia, has a high diversity of macrobenthic invertebrates and is increasingly affected by human activities. We found > 50 organic contaminants in water, sediment and macrobenthic invertebrates from the lagoon most of which were polycyclic aromatic compounds (PACs). Composition of PACs pointed to petrogenic contamination in the eastern lagoon. PACs mainly consisted of alkylated PAHs, which are more abundant in crude oil than parent PAHs. Highest total PAC concentration in sediment was above reported toxicity thresholds for aquatic invertebrates. Other identified compounds derived from municipal sewage and also included novel contaminants like triphenylphosphine oxide. Numbers of stored contaminants varied between species which is probably related to differences in microhabitat and feeding mode. Most contaminants were detected in Telescopium telescopium and Polymesoda erosa. Our findings suggest that more attention should be paid to the risk potential of alkylated PAHs, which has hardly been addressed previously. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Storms do not alter long-term watershed development influences on coastal water quality.

    Science.gov (United States)

    Chen, Yushun; Cebrian, Just; Lehrter, John; Christiaen, Bart; Stutes, Jason; Goff, Josh

    2017-09-15

    A twelve year (2000-2011) study of three coastal lagoons in the Gulf of Mexico was conducted to assess the impacts of local watershed development and tropical storms on water quality. The lagoons have similar physical and hydrological characteristics, but differ substantially in the degree of watershed urban development and nutrient loading rates. In total the lagoons experienced 22 storm events during the period studied. Specifically, we examine (1) whether there are influences on water quality in the lagoons from watershed development, (2) whether there are influences on water quality in the lagoons from storm activity, and (3) whether water quality is affected to a greater degree by watershed development versus storm activity. The two urbanized lagoons typically showed higher water-column nitrate, dissolved organic nitrogen, and phosphate compared with the non-urbanized lagoon. One of the urbanized lagoons had higher water-column chlorophyll a concentrations than the other two lagoons on most sampling dates, and higher light extinction coefficients on some sampling dates. The non-urbanized lagoon had higher water-column dissolved oxygen concentrations than other lagoons on many sampling dates. Our results suggest long-term influences of watershed development on coastal water quality. We also found some evidence of significant storm effects on water quality, such as increased nitrate, phosphate, and dissolved oxygen, and decreased salinity and water temperature. However, the influences of watershed development on water quality were greater. These results suggest that changes in water quality induced by human watershed development pervade despite the storm effects. These findings may be useful for environmental management since they suggest that storms do not profoundly alter long-term changes in water quality that resulted from human development of watersheds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Divorce in the context of domestic violence against women in Vietnam

    NARCIS (Netherlands)

    Vu, H.S.; Schuler, S.; Hoang, T.A.; Quach, T.

    2014-01-01

    This paper examines obstacles for women who face domestic violence in making decisions about divorce and in seeking and securing support for a divorce. The research was undertaken in the context of a project in one district of a coastal province in Vietnam that sought to reduce gender based-violence

  4. Support mechanisms for oil spill accident response in costal lagoon areas (Ria de Aveiro, Portugal)

    Science.gov (United States)

    Oliveira, Eduardo R.; Silveira, Bruno; Alves, Fátima L.

    2014-10-01

    Oil spill accidents can be caused by several risk factors associated to maritime transport and port activities, which cannot always be predicted or controlled. Therefore, it is essential to support prevention and contingency plans, whose effectiveness is crucial to produce adequate responses and minimize resulting impacts. Ria de Aveiro (Portugal) is a wide coastal lagoon, within a densely populated area, representing a concentration of important biodiversity resources and several economic activities. This paper presents alternative methodologies to support the optimization of civil protection assets in the occurrence of oil spill events and the results of their application on a section area of the Aveiro Lagoon, using an established geographic information system database containing crucial data. The presented methodologies are based on the Environmental Sensitivity Index developed by the North American National Oceanic and Atmospheric Administration (USA) and the Global Vulnerability Index which were applied on the Bay of Biscay (Spain). However, during the development of this work, neither of these methodologies was considered to entirely assess the study area in its full extent, which led to the need to adapt and define a bespoke approach. The introduced changes include extra categories in shoreline classification, an adapted physical vulnerability index for coastal lagoons, differentiated aspects for highly protected status areas, qualitative assessment of socioeconomic features and an access and operability index created to support emergency operation response. The resulting maps are the subject of analysis, in which considerations regarding control and cleanup methods are introduced, together with guidelines for further integration in local risk management strategies.

  5. The Lessons of the Vietnam War.

    Science.gov (United States)

    Starr, Jerold M., Ed.

    This text book on the Vietnam War is to be used in teaching high students. Each of the volume's 12 chapters is a self-contained unit on an aspect of the War. The chapters are: (1) Introduction to Vietnam: land, history, and culture; (2) America at war in Vietnam: decisions and consequences; (3) Was the Vietnam War legal? (4) who fought for the…

  6. Developing School Psychology in Vietnam

    Science.gov (United States)

    Le, Phuong; Hagans, Kristi; Powers, Kristin; Hass, Michael

    2011-01-01

    Like China, Vietnam is a communist country with increasingly capitalist economic policies. A fundamental change occurred in these policies with the enactment of Vietnam's "doi moi" (renovation) policy in 1986 that called for a "free market with socialist orientations." However, this economic modernization has inadvertently…

  7. Climate change, sea level rise and coastal inundation along part of ...

    African Journals Online (AJOL)

    The phenomenon of ocean surges and other morphological processes along the Lagos coastline have generated serious public concern on the vulnerability of infrastructures and coastal services along the entire stretch of the Barrier-Lagoon coastline of Lagos State. This study examines Badagry coastal environment ...

  8. The use of aquatic environments for Scientific Education purposes: the case of the Imboassica Lagoon, Macaé, RJ

    Directory of Open Access Journals (Sweden)

    Laísa Maria Freire dos Santos

    Full Text Available AIM: The present work aims to discuss the potential use of aquatic environments for teaching purposes, taking the Imboassica Lagoon and its environmental problems as an example. METHODS: A case study method including a literature review focused on Limnology and Science Education fields (SE. The case study was developed by describing and evaluating activities performed in the Imboassica Lagoon, considering contemporary SE approaches. MAJOR RESULTS: We featured environmental problems in the Imboassica Lagoon and discussed questions related to facing the problems and the construction of educational processes that generate concepts able to change reality. The activities performed in the Imboassica Lagoon provided the opportunity to set a discussion among teachers and students about different themes related to coastal lagoons' ecology based on a politicized SE viewpoint. Among some of the key aspects related to the practices performed, we could identify: the partnership between universities and schools; the contribution to develop individuals aware of citizen senses, integrating aspects of science, technology and society in field activities. The following limits were identified: the need to develop an integrated action with the school curriculum and the need to develop a plan of action with the active participation of elementary school teachers. CONCLUSIONS: The current study presented challenges for the limnologists, in order to reflect upon the social implications of their research practice seeking interaction with other sectors of society and other knowledge fields, to enhance the horizons of scientific education.

  9. Ecological risk assessment of a coastal zone in Southern Vietnam: Spatial distribution and content of heavy metals in water and surface sediments of the Thi Vai Estuary and Can Gio Mangrove Forest.

    Science.gov (United States)

    Costa-Böddeker, Sandra; Hoelzmann, Philipp; Thuyên, Lê Xuân; Huy, Hoang Duc; Nguyen, Hoang Anh; Richter, Otto; Schwalb, Antje

    2017-01-30

    Enrichment of heavy metals was assessed in the Thi Vai Estuary and in the Can Gio Mangrove Forest (SE, Vietnam). Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn contents in water and in sediments were measured. Total organic carbon, nitrogen, phosphorus and C/N ratios were determined. Cu and Cr values were higher than threshold effect level of toxicity, while Ni exceeded probable effect level, indicating the risk of probable toxicity effects. Enrichment factors (EF), contamination factor (CF) and Geo-accumulation index (I-geo) were determined. CF reveals moderate to considerable pollution with Cr and Ni. EF suggests anthropogenic sources of Cr, Cu and Ni. I-geo indicates low contamination with Co, Cu and Zn and moderate contamination with Cr and Ni. Overall metal contents were lower than expected for this highly industrialized region, probably due to dilution, suggesting that erosion rates and hydrodynamics may also play a role in metal contents distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Nutrients fluxes from groundwater discharge into Mangueira Lagoon (Rio Grande do Sul, Brazil); Fluxos de nutrientes associados as descargas de agua subterranea para a Lagoa Mangueira (Rio Grande do Sul, Brasil)

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Carlos F.F.; Niencheski, Luis F.H.; Attisano, Karina K.; Milani, Marcio R., E-mail: pgofcfa@furg.br [Instituto de Oceanografia, Universidade Federal do Rio Grande, Campus Carreiros, Rio Grande, RS (Brazil); Santos, Isaac R. [Department of Oceanography, Florida State University, Tallahassee, FL (United States); Milani, Idel C. [Departamento de Engenharia Hidrica, Centro de Desenvolvimento Tecnologico, Universidade Federal de Pelotas, Campus Porto, Pelotas, RS (Brazil)

    2012-07-01

    This study assesses the importance of groundwater discharge to dissolved nutrient levels in Mangueira Lagoon. A transect of an irrigation canal in the margin of Lagoon demonstrated a strong geochemical gradient due to high groundwater inputs in this area. Using {sup 222}Rn as a quantitative groundwater tracer, we observed that the flux of dissolved inorganic nitrogen (DIN), silicate and phosphate (1178 and 1977; 26190 and 35652; 167 and 188 mol d{sup -1} for winter and summer, respectively) can continually supply/sustain primary production. The irrigation canals act as an artificial underground tributary and represent a new source of nutrients to coastal lagoons. (author)

  11. The distribution of micro zooplankton in the lagoon environments; La distribuzione del microzooplancton negli ambienti lagunari

    Energy Technology Data Exchange (ETDEWEB)

    Grenni, P.; Creo, C. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1998-07-01

    The aim of this work is to verify the possible use of micro zooplankton as a biological indicator in aquatic environments. In particular, studies carried out in lagoon environments are reported, relatively to the Venice lagoon and the Pontine coastal lakes (Italy). New methodologies to assess the micro plankton component are developed and tested, particularly the concentration and count steps. The use of the same methodologies to assess nano plankton component, as biological indicator. are reported. [Italian] Nel presente lavoro viene analizzata la possibilita' di utilizzare il microzooplancton quale indicatore biologico negli ambienti acquatici (mmarini, acquadulcicoli, salmastri). In particolare, vengono riportati gli studi effettuati dall'ENEA (National Agency for New Technology, Energy and the Environment) su tale componente in ambienti lagunari, con riferimento alla laguna di Venezia e alle lagune pontine.

  12. Carbon mass-balance modeling and carbon isotope exchange processes in the Curonian Lagoon

    Science.gov (United States)

    Barisevičiūtė, Rūta; Žilius, Mindaugas; Ertürk, Ali; Petkuvienė, Jolita

    2016-04-01

    The Curonian lagoon one of the largest coastal lagoons in Europe is located in the southeastern part of the Baltic Sea and lies along the Baltic coast of Lithuania and the Kaliningrad region of Russia. It is influenced by a discharge of the Nemunas and other smaller rivers and saline water of the Baltic Sea. The narrow (width 0.4 km, deep 8-14 m) Klaipėda Strait is the only way for fresh water run-off and brackish water intrusions. This research is focused on carbon isotope fractionations related with air - water exchange, primary production and organic carbon sedimentation, mineralization and uptake from both marine and terrestrial sources.

  13. Punctuated sediment record resulting from channel migration in a shallow sand-dominated micro-tidal lagoon, Northern Wadden Sea, Denmark

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Andersen, Thorbjørn Joest; Nielsen, Lars Henrik

    2011-01-01

    Facies analysis of five sediment cores and a detailed absolute chronology, consisting of 35 optically stimulated luminescence (OSL) ages, form the basis for reconstruction of the paleoenvironmental evolution of the coastal lagoon behind the barrier island of Fanø, in the Northern Wadden Sea, SW D...

  14. Early chemical and ecotoxicological responses of the Varano lagoon (SE Italy) to a flood event.

    Science.gov (United States)

    Fabbrocini, Adele; Cassin, Daniele; Santucci, Angela; Scirocco, Tommaso; Specchiulli, Antonietta; D'Adamo, Raffaele

    2017-10-01

    The effects on coastal lagoons of floods resulting from intense rainfall need to be assessed using a multidisciplinary approach, able to describe in real time the occurrence of changes in sediment quality, anticipating risk situations. In the present study the effectiveness as pre-screening tool of the MOT-test, an innovative bioassay that uses sperm motility as endpoint, has been evaluated; its response has been compared with the sediment chemical characterization, in order to determine the effects of a flood event occurred in the Varano lagoon, a poorly anthropized Mediterranean coastal lagoon. The MOT-test effect percentages ranged from 10% to 30%, fully reflecting data from chemical analyses. Organic pollutants showed concentrations always below the critical levels. The highest metal values were found in the south-eastern area; however, only for few metals (mainly Cd), and in few sites, they reached the limits defined by the sediment quality guidelines; consistently, these sites are located in the area where a higher stressors' impact was expected and the highest MOT-test effect percentages were recorded. In conclusion, even if results exclude the occurrence of serious contamination events as a consequence of the flood, the runoff resulting from the intense rainfall event has caused a pollutant load in the lagoon, consistent with the localization of the main anthropogenic activities in the catchment area. Moreover, preliminary data indicate the validity of the approach adopted for the post-flood quality assessment, proving the usefulness of the MOT-test as early-screening tool in the case of extreme events. Copyright © 2017. Published by Elsevier Inc.

  15. Tobacco control in Vietnam.

    Science.gov (United States)

    Tran, D T; Kosik, R O; Mandell, G A; Chen, Y A; Su, T P; Chiu, A W; Fan, A P

    2013-02-01

    To investigate the use of tobacco in Vietnam. Review study. Data were collected through a review of tobacco-related literature in Vietnam. Grey literature and web content from agencies such as the World Health Organization and the US Centers for Disease Control and Prevention were consulted. Tobacco smoking is still common in Vietnam, although numerous policies have been issued and implemented over the last two decades. Based on the most recent data (2010), the prevalence of smoking among adults aged >15 years was 23.8%, with a higher percentage among males (47.4%) than females (1.4%). The prevalence of smoking among students aged 13-15 was 3.8% (2007), with a similar gender pattern. The prevalence of exposure to secondhand smoke is of concern, with 73.1% and 55.9% of adults reporting exposure to secondhand smoke at home and at work or other places, respectively. Of the adult respondents, 55.5% believed that smoking may cause lung cancer, stroke and heart disease. Most students (93.4%) and adults (91.6%) had seen anti-smoking media messages. Of the students, 56.4% had seen pro-cigarette advertisements on billboards, 36.9% had seen pro-cigarette advertisements in newspapers or magazines, and 8.2% had been offered free cigarettes by tobacco company representatives. The price of cigarettes decreased by approximately 5% between 1995 and 2006, whereas gross domestic product per capita increased by more than 150%. On average, smokers smoked 13.5 cigarettes per day, and spent US$86 on cigarettes per year. Despite such high levels of tobacco exposure in Vietnam, the total tax on cigarettes remains at 45% of the retail price. Furthermore, only 29.7% of smokers had been advised to quit by a healthcare provider in the past 12 months. Strong enforcement and evidence-based regulations which rounded on MPOWER are needed to help protect current smokers and non-smokers from the devastating effects of tobacco. Copyright © 2012 The Royal Society for Public Health. Published by

  16. Coastal management at Ojo de Liebre, Baja California Sur

    Science.gov (United States)

    Frederico Salinas-Zavala; Alfredo Ortega-Rubio; Diego Valez-Zamudio; Aradit. Castelanos-Vera

    2000-01-01

    We analyzed the biotic, abiotic, and human components interacting at the coastal zone of the Ojo de Liebre Lagoon, Baja California Sur, Mexico. Using geographic information systems, satellite images, and the main biological, physical, and socioeconomic components, we developed an environmental characterization of the zone. According with the natural features of the...

  17. CASE STUDY: Vietnam — Information brings progress to Vietnam's ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    In Vietnam, a community-based monitoring system builds on existing official poverty surveys to better target the poor. The additional data has led to improvements in communities, and in the lives of women in particular.

  18. Lagoon pollution and nutritive compounds change in urban tropical ...

    African Journals Online (AJOL)

    Lagoon pollution and nutritive compounds change in urban tropical area. ... column changed depending on environmental conditions. The evolution of these pollutions effects may jeopardize the sustainability of the Abidjan lagoon system. Keywords: Wastewater, Ebrie Lagoon, rainfall, oxidizable organic matter, suspended ...

  19. Environmental changes in the Moulay Bousselham lagoon (Morocco) during the last 7 000 years using a multiproxy approach

    Science.gov (United States)

    Zourarah, Bendahhou; Maanan, Mohamed; Conceição Freitas, Maria; Leroy, Suzanne; Andrade, César; Cearreta, Alejandro; Cruces, Anabela

    2016-04-01

    The aim of this research is to reconstruct Holocene environmental changes in Moulay Bousselham lagoon using a multi-proxy approach to the study of sediments of two short cores: biological (e.g., pollen, foraminifera and diatoms), physicochemical (isotopes, chemical composition) and sedimentary (grain size, clay minerals). The research highlights the role of climatic variations and human interference in the evolution of this lagoon. The results show that at the beginning of the Holocene this area corresponded to a wide coastal bay, including the surface of Moulay Bousselham present-day lagoon and Merja Ras Ed-Dora. The dating's obtained in the base of the sediment cores range from 6790-6640 BP (end of the Atlantic and early Sub-boreal). Sand predominates in this section of the cores, with low content of organic matter and high content of bioclasts. Ammonia tepida is the predominant species but Haynesina germânica, Quinqueloculina semínula,Cibicides lobatulus,Criboelphidium oceanensis and Miliolinella sobrotunda are also presente. At the base, foraminifera assemblages show a relative abundance of Planorbulina mediterranensis, Rosalina anomala, Rosalina irregularis, Miliolinella subrotunda and Cibicides lobatulus. These are typical of a shallow environment with normal marine salinity. During the sub-boreal period (6640-4520 BP), a sandy barrier developed and the lagoon evolved to a brackish lagoon with low salinity. Sedimentation is homogeneous, the content of silt and clay is high (90%), calcium carbonate content is usually lower than 20% and the organic material exhibited the highest values (> 10%). Ammonia tepida is also the dominant species but C. oceanensis and H. germanica are secondary. The lagoon was closed in drier conditions and has gradually filled by sediments coming from the watershed, represented by an illite-chlorite association. The lagoon evolved to a sabkha. We must emphasize the role of deforestation caused by the Romans (2100 BP) in that period

  20. Coastal Morphology and Coastal Protection

    NARCIS (Netherlands)

    Van de Graaff, J.

    2009-01-01

    Lecture notes ct5309. Tides, currents and water; coastal problems; sediment transport processes; coastal transport modes; longshore transport; cross-shore transport; fundamentals of mud; channels and trenches; coastal protection; application of structures; application of nourishments.

  1. Study of water chlorophyl content in the Venice Lagoon through hyperspectral data

    Science.gov (United States)

    Garfagnoli, Francesca; Bizzaro, Beatrice; Moretti, Sandro

    2013-04-01

    In the framework of the HICO Project (http://hico.coas.oregonstate.edu/), a number of radiance and reflectance images of the Venice Lagoon were used to evaluate the possibility of performing quick and reliable mapping of water quality parameters. Sponsored by the Office of Naval Research, the Hyperspectral Imager for the Coastal Ocean (HICO™) is the first spaceborne imaging spectrometer specifically designed to sample the coastal areas, with 128 spectral bands, a 90 m spatial resolution, full spectral coverage (380 to 960 nm sampled at 5.7 nm) and a very high signal-to-noise ratio to resolve the complexity of the coastal ocean. Eutrophication is one of the major causes of water quality deterioration. The concentration of chlorophyll-a found in water can be used to trace the abundance of planktonic algae in rivers, lakes or lagoons. The Venice Lagoon, famous worldwide, represents one of the most fragile and vulnerable ecosystems, which is being constantly threatened by factors of stress, both human and natural, such as erosion, presence of urban and agricultural sources of pollution, stress from fishing, pollution produced by the industrial area of Porto Marghera and by the city of Venice itself, downwash of sediments from the hinterland and eutrophication. Traditional methods of water quality estimation are often time consuming and involve periodical sampling and plenty of laboratory analyses. In this study the possibility of using imaging spectroscopy to rapidly obtain raster-based maps of chlorophyll concentration by comparing the results obtained through five different literature bio-optical models, which permit the retrieval of mathematical relations between the water's spectral properties and physicochemical parameters; pH, dissolved oxygen, turbidity and chlorophyll concentration. Evaluation of performances is achieved by comparing the hyperspectral based maps with maps of kriged concentration values, provided by the Magistrato delle Acque di Venezia (http

  2. Vietnam's population: current notes.

    Science.gov (United States)

    Fraser, S E

    1984-06-01

    In an effort to curb the population growth rate, currently estimated at 2.5%/year, the government of Vietnam has stepped up its campaign to implement a national family planning program. 1979 census figures indicate a population of 52.76 million. There is increasing government awareness of the interaction between population growth, employment, and manpower utilization. The demographic realities of Vietnam necessitate a drastic decrease in fertility rates and family size, a redistribution of the population either through internal migration to new economic zones or transborder migration, and a more efficient use of land and exploitation of natural and human resources to support the growing population. Assuming a natural increase rate of less than 2% by 1984-85, the government estimates a total population of nearly 60 million by the end of 1985. It is hoped that a natural growth rate of 1% can be attained in the early 1990s, to achieve a population size below 75 million by the year 2000. However, if the 3-child family remains the norm, the population will approach 80-85 million by 2000. Changes in shortterm fertility patterns seem unlikely without a carefully thought out and sensitively implemented policy involving a deliberate scheme of incentives and disincentives. The Vietnam Fatherland Front (VFF) has recognized the need for a more regorous fertility control campaign and has requested that the Council of Ministers set up a coordinated population and family planning structure with direct linkages from Hanoi to provincial governments and communal administrations. Also recommended were regulations on birth control, population targets and norms, and a system of incentives and disincentives. Data from family planning services in Ho Chi Minh City for 1976-82 suggest a recent decline in IUD, condom, and pill users, largely as a result of procurement difficulties. The number of abortions has also declined because of successful family planning education. The ideal family

  3. Seasonal Changes of Fish Assemblages in a Subtropical Lagoon in the SE Gulf of California

    OpenAIRE

    Amezcua, F.; Amezcua-Linares, F.

    2014-01-01

    The composition and seasonal changes of the fish assemblage in a coastal lagoon system in southeastern Gulf of California were assessed from December 2001 to July 2005. A total of 20,877 organisms belonging to 191 species and 47 families were analyzed. We determined that almost all the species inhabiting the system were found; however some rare species were not captured in our study. The majority of the species found were demersal but in every season at least one pelagic or benthopelagic spec...

  4. Genetic heterogeneity in populations of the Mediterranean shore crab, Carcinus aestuarii (Decapoda, Portunidae), from the Venice Lagoon

    Science.gov (United States)

    Marino, Ilaria Anna Maria; Barbisan, Federica; Gennari, Micol; Giomi, Folco; Beltramini, Mariano; Bisol, Paolo Maria; Zane, Lorenzo

    2010-03-01

    Heterogeneity in genetic composition among recruits, mostly due to a large variance in reproductive success mediated by oceanographic processes, has been reported for marine species but is less understood in coastal lagoons' organisms. Temporal genetic variation in natural populations of the Mediterranean shore crab Carcinus aestuarii was quantified over a multi-year sample. A total of 486 adult crabs were collected at eight different sites of the Venice Lagoon during the period 2005-2007 and screened for genetic variation using 11 microsatellite loci. Two additional samples (N = 115) from neighbouring sites, located approximately 100 km North and South to the Venice Lagoon, were included for the sake of comparison. Our results show significant differences in allelic frequencies at the micro-geographic scale of the Venice Lagoon, observed between sites of collection, typologies of habitat, and areas with different class of ecological risk or pattern of hemocyanin expression. However, this pattern was not constant between years, with significant differences observed mainly in 2005 and 2006, but not in 2007. Our results indicate significant temporal differences suggesting the existence of dynamic processes that act on the genetic pool of this species. Although natural selection and gene flow might play a role, we suggest that genetic drift linked to large variation in the reproductive success of individuals is the most probable scenario to explain the local genetic patterns of differentiation in the Mediterranean shore crab. Our study, by providing the first evidence for the existence of genetic differences in this species at the micro-geographic scale, suggests that a better comprehension of the link between reproduction, recruitment and oceanography is critical to understand how colonization and maintenance of genetic variation is achieved in ephemeral and vulnerable environments such as coastal lagoons.

  5. The effect of river discharge and winds on the interannual variability of the pink shrimp farfantepenaeus paulensis production in Patos Lagoon

    OpenAIRE

    Möller Junior, Osmar Olinto; Castello, Jorge Pablo; Vaz, Ana Carolina

    2009-01-01

    The Patos Lagoon estuary is an important environment for the life cycle of many species, including the pink shrimp Farfantepenaeus paulensis. This area acts as a nursery ground for the shrimp larvae, which are spawned in a coastal area and transported into the lagoon during spring and early summer (September to December). Harvesting of shrimp occurs from January to May, and yields have varied from around 1,000 to 8,000 tons year−1. This study is based on analysis of river disch...

  6. Profile of Vietnam War Veterans (2015).

    Data.gov (United States)

    Department of Veterans Affairs — The Profile of Vietnam War Veterans uses the 2015 ACS to provide a view into the demographic characteristics and socioeconomic conditions of the Vietnam War Veteran...

  7. Number One Reef: An overstepped segmented lagoon complex on the KwaZulu-Natal continental shelf

    Directory of Open Access Journals (Sweden)

    Godfrey Vella

    2012-07-01

    Full Text Available This study of the bathymetry of the mid-shelf of the Durban Bight, KwaZulu-Natal revealed a series of previously undocumented seafloor features. These features were mapped using a high-resolution multibeam bathymetric echosounder and a detailed map of the seafloor topography was produced. We recognised several features that closely resemble features of contemporary segmented lagoon and lake systems: semicircular seafloor depressions, arcuate ridges, cuspate spits and prograding submerged barriers. Based on the striking similarity in morphology to Kosi Bay – a segmented lagoon system from the sandy northern KwaZulu-Natal coastal plain – a similar evolutionary model is proposed. This model is of an incised valley formed following a sea level lowering to the Last Glacial Maximum at about 18 000 BP. Thereafter, continued transgressive infilling occurred to a point where an extensive lagoon and back-barrier system was established. At this point, sea levels remained static, causing the net segmentation of the system and the slow closure of the tidal basins or circular depressions. This type of seafloor topography is rarely preserved and is the result of fortuitous cementation after deposition and the later removal of sediment that would ordinarily bury such features.

  8. Comparison of Water Flows in Four European Lagoon Catchments under a Set of Future Climate Scenarios

    Directory of Open Access Journals (Sweden)

    Cornelia Hesse

    2015-02-01

    Full Text Available Climate change is supposed to remarkably affect the water resources of coastal lagoons as they are highly vulnerable to changes occurring at their catchment and/or ocean or sea boundaries. Probable impacts of projected climate changes on catchment hydrology and freshwater input were assessed using the eco-hydrological model SWIM (Soil and Water Integrated Model for the drainage areas of four European lagoons: Ria de Aveiro (Portugal, Mar Menor (Spain, Tyligulskyi Liman (Ukraine and Vistula Lagoon (Poland/Russia under a set of 15 climate scenarios covering the time period until the year 2100. Climate change signals for all regions show continuously increasing trends in temperature, but various trends in precipitation. Precipitation is projected to decrease in two catchments on the Iberian Peninsula and increase in the Baltic region catchment, and does not show a clear trend in the catchment located near the Black Sea. The average projected changes in freshwater inputs reflect these changes in climate conditions, but often show variability between the scenarios, in future periods, and within the catchments. According to the individual degrees of water management influences in the four drainage basins, the climate sensitivity of river inflows is differently pronounced in each.

  9. Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use

    Science.gov (United States)

    Bernhardt, C.E.; Stanley, J.-D.; Horton, B.P.

    2011-01-01

    The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ???1200 km south of Manzala. Freshwater wetland plants that were dominant, such as Typha and Phragmites, decreased rapidly, whereas in the early 1900s, brackish water wetland species (e.g., Amaranthaceae) increased. This change occurred after closure of the Aswan Low Dam in 1902. The second major modification in the pollen record occurred in the early 1970s, after Aswan High Dam closure from 1965 to 1970, when Typha pollen abundance increased rapidly. Massive population growth occurred along the Nile during the 130 years represented by the core section. During this time, the total volume of lagoon water decreased because of conversion of wetland areas to agricultural land, and input of organic-rich sediment, sewage (municipal, agricultural, industrial), and fertilizer in Manzala lagoon increased markedly. Although the wetland plant community has continued to respond to increasingly intensified and varied human-induced pressures in proximal sectors, the two most marked changes in Manzala pollen best correlate with distal events (i.e., closure of the two dams at Aswan). The study also shows that the two major vegetation changes in Manzala lagoon each occurred less than 10 years after closure upriver of the Low and High dams that markedly altered the Nile regime from Upper Egypt to the coast. ?? 2011, the Coastal Education & Research Foundation (CERF).

  10. Water pollution by intensive brackish shrimp farming in south-east Vietnam: Causes and options for control

    NARCIS (Netherlands)

    Pham Thi Ahn,; Kroeze, C.; Bush, S.R.; Mol, A.P.J.

    2010-01-01

    This paper focuses on both the environmental impact of intensive shrimp farming in the coastal region of Vietnam and the identification of options for cleaner production. We investigated water pollution, sediment contamination and the spread of diseases related to shrimp farming in the Can Gio

  11. Assessing decentralised policy implementation in Vietnam : The case of land recovery and resettlement in the Vung Ang Economic Zone

    NARCIS (Netherlands)

    J.W. de Wit (Joop); L. Viet Sang (Luong); L. Van Chien (Le); L. Thu Hien (Luong); H. Viet Hung (Ha); D. Thi Anh Tuyet (Dang); D. Ngoc Bau (Dao); Q. Hoa (Quang); M. Thi Thanh Tam (Mai)

    2012-01-01

    textabstractFrom 2006 plans were implemented to create a deep-sea water port linked to an Economic Zone in the coastal Province of Ha Tinh, located in north central Vietnam. The multi-purpose Zone entitled ‘Vung Ang’, was to attract foreign investors, while the port would provide a link to nearby

  12. 75 FR 60074 - Certain Frozen Warmwater Shrimp From the Socialist Republic of Vietnam: Notice of Correction to...

    Science.gov (United States)

    2010-09-29

    ... shrimp from Brazil, India, the People's Republic of China, Thailand, and the Socialist Republic of Vietnam. See Certain Frozen Warmwater Shrimp from Brazil, India, the People's Republic of China, Thailand....57 Aquatic Products Trading Company \\7\\ 4.57 Bac Lieu Fisheries Company Limited \\8\\ 4.57 Coastal...

  13. Curonian Lagoon drainage basin modelling and assessment of climate change impact

    Directory of Open Access Journals (Sweden)

    Natalja Čerkasova

    2016-04-01

    Full Text Available The Curonian Lagoon, which is the largest European coastal lagoon with a surface area of 1578 km2 and a drainage area of 100,458 km2, is facing a severe eutrophication problem. With its increasing water management difficulties, the need for a sophisticated hydrological model of the Curonian Lagoon's drainage area arose, in order to assess possible changes resulting from local and global processes. In this study, we developed and calibrated a sophisticated hydrological model with the required accuracy, as an initial step for the future development of a modelling framework that aims to correctly predict the movement of pesticides, sediments or nutrients, and to evaluate water-management practices. The Soil and Water Assessment Tool was used to implement a model of the study area and to assess the impact of climate-change scenarios on the run-off of the Nemunas River and the Minija River, which are located in the Curonian Lagoons drainage basin. The models calibration and validation were performed using monthly streamflow data, and evaluated using the coefficient of determination (R2 and the Nash-Sutcliffe model efficiency coefficient (NSE. The calculated values of the R2 and NSE for the Nemunas and Minija Rivers stations were 0.81 and 0.79 for the calibration, and 0.679 and 0.602 for the validation period. Two potential climate-change scenarios were developed within the general patterns of near-term climate projections, as defined by the Intergovernmental Panel on Climate Change Fifth Assessment Report: both pessimistic (substantial changes in precipitation and temperature and optimistic (insubstantial changes in precipitation and temperature. Both simulations produce similar general patterns in river-discharge change: a strong increase (up to 22% in the winter months, especially in February, a decrease during the spring (up to 10% and summer (up to 18%, and a slight increase during the autumn (up to 10%.

  14. Assessment of the Trophic State of Saquarema Lagoonal System, Rio de Janeiro (Brazil

    Directory of Open Access Journals (Sweden)

    Pierre Philippe Belart Brandão Dias

    2017-08-01

    Full Text Available This work intends to apply new ecological descriptors to a coastal marine area aiming to assess its environmental trophic status. This approach makes possible to identify relevant variables associated with eutrophication process applicable and valid worldwide. The aim of this work is to study the organic matter (OM quality and quantity, in terms of biopolymers, in Saquarema Lagoonal System (SLS located in Rio de Janeiro State (Brazil. Sediment samples collected in SLS were analyzed in this study for granulometric and geochemical data such as total organic carbon (TOC, total sulfur (TS and biopolimeric carbon (BPC concentrations, including proteins (PTN, carbohydrates (CHO and lipids (LIP. These data were combined with additional environmental parameters measured in water of the four linked lagoons that compose SLS. Data analyses allowed the identification of four distinct regions in SLS: an inner and impacted zone characterized by sediment particularly enriched in TOC, with lowest quality of OM most probably provided by contaminated effluents and rivers runoff; an outer-less impacted lagoonal area with relatively low TOC content and submitted to high hydrodynamic forces; an intermediate area characterized by transitional features between the two previously mentioned and a zone that is influenced mainly by salinity. The organic matter accumulation depends on the hydrodynamic conditions mostly governed by tidal currents. The quality of organic matter seems to be mainly influenced by the water renewal, rivers inputs and mangroves contributions as well as by the autochthonous lagoonal biological productivity. Results of this work indicate that the inner zone of SLS is being affected by eutrophication not necessarily caused by anthropic factors.

  15. Partitioning, bioavailability and origin of heavy metals from the Nador Lagoon sediments (Morocco) as a basis for their management

    Science.gov (United States)

    González, I.; Águila, E.; Galán, E.

    2007-08-01

    Nador Lagoon sediments show low trace element concentrations, and, in relation to the lagoon geochemical baseline, only some anomalies for As, Cd, Cu and Pb in the NW of the lagoon deserve to be outstanding. The distribution of major, minor and trace elements in the lagoon allows a breakdown in four zones. Between “Beni Ensar” and “Atelouane” (zone A), a quite confined zone rich in organic matter and S, the most important trace-element anomalies (As, Cd, Co, Cu, Mn, Pb, Zn) were found, mainly around industry and old mining activities. In the surrounding of the city of Nador (zone B), the anomalies correspond to Mn, Cu and Zn. The coastal barrier and Kebdana channel (zone C) show moderately concentrations of Cd, Cr and Ni at specific sites. The less polluted area is the SE of the lagoon (zone D), with no outstanding anomaly. In lagoon sediments, metal bioavailability is very low. The metal partitioning patterns show that Cu, Pb and Zn present a low availability because they are bounded to the residual, non-mobile phases of the sediments. Only in some sites, the fraction was associated with organic matter, which could be liberated easily. Arsenic is concentrated in both the residual phases and the organic matter, the latter being more available. Cadmium is mainly concentrated in some samples in the interchangeable fraction, which could be considered as a potentially toxic element because it is easily released. Concerning the origin of these trace elements, those found in zone A correspond mostly to a natural source by weathering of mount Gourougou volcanic rocks (As, Co, Cu, Pb and Zn), and to an anthropogenic origin (Cd) owing to the presence of industry and old mines. In zone B, contributions of Cu and Zn enter the lagoon through soil weathering and river-borne, and as anthropogenic pollution from urban wastes. In zone C the most important pollutant is Cd deduced to be of anthropogenic origin from the close industry and intensive agriculture area. In spite

  16. Digging navigable waterways through lagoon tidal flats: which short and long-term impacts on groundwater dynamics and quality?

    Science.gov (United States)

    Teatini, Pietro; Isotton, Giovanni; Nardean, Stefano; Ferronato, Massimiliano; Tosi, Luigi; Da Lio, Cristina; Zaggia, Luca; Bellafiore, Debora; Zecchin, Massimo; Baradello, Luca; Corami, Fabiana; Libralato, Giovanni; Morabito, Elisa; Broglia, Riccardo; Zaghi, Stefano

    2017-04-01

    Coastal lagoons are highly valued ephemeral habitats that have experienced in many cases the pressure of human activities since the development of urbanisation and economic activities within or around their boundaries. One typical intervention is dredging of canals to increase the exchange of water with the sea or for navigation purposes. In order to divert the route of large cruise liners from the historic center of Venice, Italy, the Venice Port Authority has recently proposed a project for the dredging of a new 3-km long and 10-m deep navigation canal (called Marghera-Venice Canal, MVC, in the sequel) through the shallows of the Venice Lagoon. The MVC will connect the passenger terminal located in the southwestern part of the historic center to a main channel that reaches the industrial area on the western lagoon margin. Can the new MVC facilitate saltwater intrusion below the lagoon bottom? Can the release into the lagoon of the chemicals detected in the groundwater around the industrial site be favoured by the MVC excavation? Can the depression waves generated by the ship transit (known as ship-wakes) along the MVC affect the flow and contaminant exchange between the subsurface and surficial systems? A response to these questions has been provided by the use of uncoupled and coupled density-dependent groundwater flow and transport simulators. The hydrogeological modelling has been supported by an in-depth characterization of the Venice lagoon subsurface along the MVC. Geophysical surveys, laboratory analyses on groundwater and sediment samples, in-situ measurements through piezometers and pressure sensors, and the outcome of 3D hydrodynamic and computational fluid dynamic (CFD) models have been used to set-up and calibrate the subsurface multi-model approach. The modelling results can be summarized as follows: i) the MVC has a negligible effect in relation to the propagation of the tidal regime into the subsoil; ii) the depression caused by the ship transit

  17. Diversity and composition of estuarine and lagoonal fish assemblages of Socotra Island, Yemen.

    Science.gov (United States)

    Lavergne, E; Zajonz, U; Krupp, F; Naseeb, F; Aideed, M S

    2016-05-01

    Estuarine and lagoonal surveys of Socotra Island and selected sites on the Hadhramout coast of Yemen were conducted with the objective of documenting and analysing fish diversity and assemblage structure. A total of 74 species in 35 families were recorded, among which 65 species in 32 families were from Socotra and 20 species in 17 families were from mainland Yemen. Twenty-one species represent new faunal records for Socotra. Including historic records re-examined in this study, the total fish species richness of estuaries and lagoons of Socotra Island reaches 76, which is relatively high compared to species inventories of well-researched coastal estuaries in southern Africa. Five species dominate the occurrence and abundance frequencies: Terapon jarbua, Hyporhamphus sindensis, Aphanius dispar, Ambassis gymnocephala and Chelon macrolepis. Rarefaction and extrapolation analyses suggest that the actual number of fish species inhabiting some of those estuaries might be higher than the one observed. Thus, additional sampling at specific sites should be conducted to record other less conspicuous species. Ordination and multivariate analyses identified four main distinct assemblage clusters. Two groups are geographically well structured and represent northern Socotra and mainland Yemen, respectively. The other two assemblage groups tend to be determined to a greater extent by the synchrony between physical (e.g. estuary opening periods) and biological (e.g. spawning and recruitment periods) variables than by geographical location. Finally, the single intertidal lagoon of Socotra represents by itself a specific fish assemblage. The high proportion of economically important fish species (38) recorded underscores the paramount importance of these coastal water bodies as nursery sites, and for sustaining vital provisioning ecosystem services. © 2016 The Fisheries Society of the British Isles.

  18. Vietnam and the regional crisis

    DEFF Research Database (Denmark)

    Masina, Pietro Paolo

    2002-01-01

    The paper explores the linkages between Vietnam and the regional economy before and after the East Asian financial crisis of 1997 and 1998, indicating that the country is more closely associated with the region than normally assumed. Thus, key indicators, such as falling foreign direct investment...... (including a restructuring of the so-called 'flying geese' pattern) Vietnam's chances of benefitting from closer integration in the world economy will depend on a clearcut industrial and trade policy, rather than on embarking a so-called 'neutral trade regime'. Preliminary evidence seems to indicate...... that Vietnam can successfully exploit market niches opened up by postcrisis regional economic reorganisation, thus offering some optimism for the country's immediate economic future....

  19. Coastal Engineering

    OpenAIRE

    Van der Velden, E.T.J.M.

    1989-01-01

    Introduction, waves, sediment transport, littoral transport, lonshore sediment transport, onshore-offshore sediment transport, coastal changes, dune erosion and storm surges, sedimentation in channels and trenches, coastal engineering in practice.

  20. Analysis of the Szczecin Lagoon waters fungi

    Directory of Open Access Journals (Sweden)

    Waldemar Dąbrowski

    2014-08-01

    Full Text Available Quantitative and qualitative analysis of the Szczecin Lagoon waters was carried out between April and December 1996. Changes in yeasts numbers of this particular estuary were found to be typical for the marinę and estuary waters with maximum concentration of yeast-like fungi in the summer season. Qualitative analysis of the isolated strains, proved Rhodotorula glutinis to be the most frequently isolated species at the three sampling sites, with Candida coliculosa dominating at the forth one.

  1. Santa Margarita Lagoon Water Quality Monitoring Data

    Science.gov (United States)

    2012-08-01

    could not be avoided. The bridge construction also led to a requirement to move the lower lagoon monitoring location half way through the data...6 3. Photo of Railroad Bridge construction . The berm on the right side of the photo was where the sensor package was mounted...Railroad Bridge and then moved in July 2011 to the south shore Riprap area after bridge construction began

  2. PESTICIDE RESIDUES IN THE WATER AND FISH (LAGOON ...

    African Journals Online (AJOL)

    Preferred Customer

    of a particular pesticide or group of pesticides found in a commodity (that is food or water) after ..... MRL (ADI) [12]. 0.004. 0.0020. 0.0100. 0.0030. ELF: Etsii Lagoon fish sample, FLF: Fosu Lagoon fish sample. Also, the total pesticide residues were higher in fish samples from the Fosu lagoon (0.0155 mg/kg) than that which ...

  3. Coastal sedimentation

    Science.gov (United States)

    Schubel, J. R.

    1980-01-01

    Several important coastal sedimentation problems are identified. Application of existing or anticipated remote sensing techniques to examine these problems is considered. Specifically, coastal fine particle sediment systems, floods and hy hurricanes and sedimentation f of coastal systems, routes and rates of sediment transport on continental shelves, and dredging and dredged material disposal are discussed.

  4. Reproductive ecology of the blue crab, Callinectes danae Smith, 1869 in the Conceição Lagoon system, Santa Catarina Isle, Brazil.

    Science.gov (United States)

    Branco, J O; Masunari, S

    2000-02-01

    Abundance of ovigerous females, size of the first gonadal maturation and the possible migration, route of the blue crab Callinectes danae from the Conceição Lagoon system, Santa Catarina Isle, Brazil, are described. This lagoon is connected with the coastal area through a canal. A total of 1,124 crabs was caught during a 19 month sampling period. The reproduction and recruitment of juveniles occurred all year-round, with two peaks of abundance (February and September), correlated with the presence of ovigerous females (June and January). The mean carapace width at which the crabs attained gonadal maturity for the first time was 9.4 cm in males and 8.4 cm in females. The Conceição Lagoon is a growth, reproduction, and spawning area for the species. However, egg eclosion occurs outside the lagoon following migration of ovigerous females to the open sea. After hatching the eggs, some females return to the lagoon, but males stay there for most of their life cycle.

  5. Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia): a multi-proxy approach

    Science.gov (United States)

    Affouri, Aida; Dezileau, Laurent; Kallel, Nejib

    2017-06-01

    Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe / Ca and Ti / Ca) characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995). Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

  6. Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia: a multi-proxy approach

    Directory of Open Access Journals (Sweden)

    A. Affouri

    2017-06-01

    Full Text Available Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe ∕ Ca and Ti ∕ Ca characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995. Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

  7. From Combat to Legacies: Novels of the Vietnam War.

    Science.gov (United States)

    Johannessen, Larry R.

    1995-01-01

    Discusses novels of the Vietnam War, their usefulness, and the interest they hold for students. Considers four categories of Vietnam novels: the Vietnam experience, the war at home, the refugee experience, and the war's effect on the next generation. (SR)

  8. The structure and productivity of the Thalassia testudinum community in Bon Accord Lagoon,Tobago

    Directory of Open Access Journals (Sweden)

    Rahanna A Juman

    2005-05-01

    Full Text Available The Thalassia testudinum dominated seagrass community in the Buccoo Reef/Bon Accord Lagoon Marine Park,measures 0.5 km² and is part of a contiguous coral reef,seagrass bed and mangrove swamp system in southwest Tobago.T.testudinum coverage,productivity and percent turnover rates were measured from February 1998 to February 1999 at four sample locations,while total T.testudinum biomass was measured at two locations in the lagoon from 1992-2002.Productivity and turnover rates varied spatially and seasonally. They were higher in the back-reef area than in the mangrove-fringed lagoon,and were lowest at locations near to a sewage outfall.T.testudinum coverage ranged from 6.6%in the lagoon to 68.5%in the back-reef area while productivity ranged from 3.9 to 4.9 g dry wt m-2 d-1 .Productivity and percentage turnover rates were higher in the dry season (January -Junethan in the wet season (July -December.Productivity ranged from 3.0 in the wet season to 5.0 g dry wt m-2 d-1 in the dry season while percentage turnover rates ranged from 4.2%to 5.6%.Total Thalassia biomass and productivity in Bon Accord Lagoon were compared to six similar sites in the Caribbean that also participate in the Caribbean Coastal Marine Productivity Program (CARICOMP.This seagrass community is being negatively impacted by nutrient-enriched conditions.La comunidad de pastos marinos de Buccoo Reef/ Parque Nacional Bon Accord Lagoon,dominado por Thalassia testudinum,mide 0.5 km² y es parte de un complejo de arrecifes,lechos de pastos marinos y manglares en el suroeste de Tobago.La cobertura,productividad y tasa de recambio de T.testudinum fueron medidas de febrero 1998 a febrero 1999 en cuatro localidades,mientras que la biomasa total de T.testudinum fue medida en dos localidades en la laguna,entre 1992-2002.La productividad y la tasa de recambio variaron espacialmente y estacionalmente.Fueron mayores en la parte trasera del arrecife que en el manglar y la laguna del arrecife

  9. Greening textile industry in Vietnam

    NARCIS (Netherlands)

    Nguyen Thi Phuong, L.

    2011-01-01

        The textile and garment industry has made a remarkable contribution to the economic development of Vietnam and employs currently a large labor force of 2.5 million people.However, the textile industry is also seen as a most polluting and unsustainable industry due to the use of

  10. Measurement and analysis of atmospheric ammonia emissions from anaerobic lagoons

    Science.gov (United States)

    Aneja, V. P.; Bunton, B.; Walker, J. T.; Malik, B. P.

    Ammonia-nitrogen flux (NH 3-N=(14/17)NH 3) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of flux variation was made with respect to lagoon surface water temperature (˜15 cm below the surface), lagoon water pH, total aqueous phase NH x(=NH 3+NH 4+) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3 °C. The pH ranged in value from 6.8 to 8.1. Aqueous NH x concentration ranged from 37 to 909 mg N l -1, and TKN varied from 87 to 950 mg N l -1. Fluxes were the largest at the primary lagoon in Kenansville, NC (March 1999) with an average value of 120.3 μg N m -2 min -1, and smallest at the tertiary lagoon in Rocky Mount, NC (November 1998) at 40.7 μg N m -2 min -1. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NH x concentration. The NH 3-N flux may be modeled as ln(NH 3-N flux)=1.0788+0.0406 TL+0.0015([NH x]) ( R2=0.74), where NH 3-N flux is the ammonia flux from the lagoon surface in μg N m -2 min -1, TL is the lagoon surface water temperature in °C, and [NH x] is the total ammonia-nitrogen concentration in mg N l -1.

  11. Assessment of human activities impact on groundwater quality discharging into a reef lagoon

    Science.gov (United States)

    Rebolledo-Vieyra, M.; Hernandez, L.; Paytan, A.; Merino-Ibarra, M.; Lecossec, A.; Soto, M.

    2010-03-01

    The Eastern coast of the Yucatan Peninsula has the fastest growth rate in Mexico and groundwater is the only source of drinking water in the region. The consequences of the lack of proper infrastructure to collect and treat wastewater and the impact of human activities on the quality of groundwater are addressed. The groundwater in the coastal aquifer of Quintana Roo (SE Mexico) discharges directly into the ocean (Submarine Groundwater Discharges). In addition, the coral reef of the Eastern Yucatan Peninsula is part of the Mesoamerican Coral Reef System, one of the largest in the world. The interaction of the reef-lagoon hydraulics with the coastal aquifer of Puerto Morelos (NE Yucatan Peninsula), and a major input of NH4, SO4, SiO2, as a consequence of the use of septic tanks and the lack of modern wastewater treatment plants are presented. A conceptual model of the coastal aquifer was developed, in order to explain how the human activities are impacting directly on the groundwater quality that, potentially, will have a direct impact on the coral reef. The protection and conservation of coral reefs must be directly related with a policy of sound management of coastal aquifers and wastewater treatment.

  12. Mineral resources of Vietnam

    Directory of Open Access Journals (Sweden)

    Kušnír Imrich

    2000-06-01

    Full Text Available Vietnam je bohatý na nerastné suroviny, ktoré sa nachádzajú prevažne na severe krajiny. Ložiská bauxitov, fosfátov, vzácnych zemín (REE, majú svetový význam. Ale i zásoby celého radu ïalších surovín (ropy, uhlia, zlata, železných rúd, chromitu, cínu, ilmenitu, medi, grafitu, atï. sú významné, ekonomicky ažite¾né a ich potenciál je obrovský. Za uvedené nerastné bohatstvo je „zodpovednᓠrozmanitá geologická stavba krajiny. Taktiež i morfológia a klíma (vlhká, tropická prispeli ku vytvoreniu niektorých ložísk (bauxity v krasových priehlbniach, atï.. Súèasná produkcia, okrem ropy (3,5 Mt/rok, zahròuje: 10,7 Mt uhlia, 3,5 Mt chromitu, asi 1 000 kg zlata, grafitu, kaolínu a mnohé iné minerály. Napriek tomu, je banícky priemysel v porovnaní so surovinovou základòou slabo vyvinutý. K jeho rozvoju urèite prispeje i úèas zahranièných spoloèností, odnedávna prítomných pri prieskume a ažbe surovín urèených pre export. Okrem struèného úvodu do geológie krajiny, obsahuje tento èlánok krátky popis nerastného bohatstva Vietnamu.

  13. assessment of water quality parameters of kpeshi lagoon of ghana

    African Journals Online (AJOL)

    User

    ABSTRACT: A study was carried out on the Kpeshi Lagoon to identify the chemical and physical characteris- tics of the water. A lot of industrial activities are carried out around the Lagoon and it is being gradually turned into a place of refuse damp. Standard methods were used for determining of chemical and physical ...

  14. Oualidia lagoon, Morocco: an estuary without a river | Hilmi | African ...

    African Journals Online (AJOL)

    Coupled 2D hydrodynamic and advection-dispersion models (MIKE21) were then used to verify some renewal times. The tidally averaged renewal time for the whole lagoon was found to be 7 days, while the local renewal time at the upstream end of the lagoon was 25 days. Finally, an inverse modelling approach using ...

  15. Assessment of Water Quality Parameters of Kpeshie Lagoon of Ghana

    African Journals Online (AJOL)

    A study was carried out on the Kpeshi Lagoon to identify the chemical and physical characteristics of the water. A lot of industrial activities are carried out around the Lagoon and it is being gradually turned into a place of refuse damp. Standard methods were used for determining of chemical and physical characteristics of ...

  16. Distribution pattern of enteric organisms in the Lagos Lagoon, Nigeria

    African Journals Online (AJOL)

    A wide range of organisms was encountered in the 24 sampled sites of the Lagos Lagoon. The enteric gram-negative shortrods, Lactose fermenting organisms such as Klebsiella spp, Enterobacter spp and Escherichia coli were prevalent in most of the Lagoon sites studied. The in vitro antibiotic sensitivity profile of the ...

  17. Fish Resources And Physico-Chemical Parameters Of Lagoon In ...

    African Journals Online (AJOL)

    A study was conducted to determine distribution and abundance of fish over two years (dry and wet seasons) in lagoon systems of Ogun waterside Local Government Area, Ogun State, Nigeria. Fish sampling was carried out in four selected stations based on catch. Physical and chemical characteristics of the lagoon ...

  18. Sewage input effects on the macroinvertebrate community associated to Typha domingensis Pers in a coastal lagoon in southeastern Brazil Efeitos do aporte de esgotos sobre a comunidade de macroinvertebrados associada à Typha domingensis Pers em uma lagoa costeira no Sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    C. Henriques-de-Oliveira

    2007-02-01

    Full Text Available This study was carried out at Imboassica Lagoon, located in an urban zone in the municipality of Macaé, Rio de Janeiro state, Brazil. This lagoon has been subject to anthropogenic impacts due to the increasing city population, such as the input of sewage. Areas of variable degree of anthropogenic influence in the lagoon were compared regarding the structure of the macroinvertebrate community associated to Typha domingensis leaves. For sampling, we used 35 x 20 cm net plastic bags, with 6.8 mm mesh containing T. domingensis leaves for colonization. Two different sampling stations were selected: station A, under direct input of sewage; and station B with lesser sewage influence. The bags were removed after 20, 40 and 75 days of colonization. For each sample the Shannon-Wiever Diversity, Pielou Evenness, Jaccard Similarity Indices, Correspondence Analysis and taxonomic richness were calculated. A total of 31,874 individuals were sampled, belonging to 34 taxa. The main taxonomical groups were: Oligochaeta (41%, Chironomidae (40%, Ancylidae (4.6%, Polymitarcyidae (4% and Thiaridae (3%. At station A, the taxonomic richness, the Evenness and Diversity values were lower than in station B. On the other hand, the total density was three times higher in station A than in B. It was already possible to discriminate the community structure of each sampling station in the first sampling. Trichoptera and Ephemeroptera were the main exclusive groups of station B and are considered good water quality indicators due to their high sensibility to contamination. The major contribution to discriminate between the macroinvertebrate communities of the two sample stations came from Chironomidae, Oligochaeta and Ephemeroptera.O presente estudo foi realizado na Lagoa Imboassica, localizada no perímetro urbano da cidade de Macaé, RJ, Brasil. Esta lagoa vem sofrendo impactos antrópicos com o aumento da cidade, como o aporte de esgotos sem tratamento. Áreas com

  19. Entry modes of European firms in Vietnam

    OpenAIRE

    Daniel Simonet

    2012-01-01

    Purpose: The purpose of the paper is to explore the entry modes of EU firms setting up operations in Vietnam. Design/methodology/approach: we use a case study approach on Haymarket, Cadbury, Creative Education, Fairchild, Aventis and Artemisinin and Farming International using interviews from managerial professionals in Vietnam. Findings: Despite the fact that Vietnam has been opening up for more than 20 years, licensing is the preferred entry mode because of the risks involved in ventur...

  20. Launching Nuoc Phan Lan brand in Vietnam

    OpenAIRE

    Pham, Huydong

    2015-01-01

    Environmental issues are emerging as another side of economic development in Vietnam. From Finland, through its strong network in South East Asia, Finnish Water Forum recognised the opportunity and the need of having a Finnish brand promoting Finnish water expertise in the environmental sector, especially water treatment in Vietnam. The research objective is to launch the brand successfully in Vietnam within 2014. In order to achieve that, this paper describes carefully the process of bu...

  1. Riqueza y diversidad de especies de aves asociadas a manglar en tres sistemas lagunares en la región costera de Oaxaca, México Richness and diversity of bird species associated with mangrove in three lagoon systems in the coastal region of Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    José Cruz Bojorges-Baños

    2011-03-01

    Full Text Available Se documentó la riqueza y diversidad avifaunística mediante capturas y conteos en las lagunas de Chacahua, Manialtepec y La Ventanilla. La diversidad de Shannon-Wiener se comparó mediante pruebas t de Hutcheson y la similitud de la riqueza avifaunística y se determinaron diferencias entre la abundancia de especies. Se generaron curvas de acumulación de especies y se estimó la riqueza con el indicador de cobertura basado en frecuencia. Se registraron 17 órdenes, 39 familias y 94 especies: 69 residentes y 25 migratorias. La abundancia no presentó diferencias (p>0.05. Hubo diferencias en la diversidad de especies entre las lagunas; La Ventanilla presentó la más elevada (3.51. La mayor similitud se obtuvo entre Chacahua y Manialtepec con 56% y la menor entre Manialtepec y La Ventanilla con 42%. La riqueza y proporción de especies residentes y migratorias fue similar en las 3 áreas; no obstante, por la baja similitud, se infiere que la diferencia en la composición de especies es significativa y que existe la posibilidad de registrar otras. Esta información complementa estudios previos, representa un inventario actualizado e indica que la avifauna asociada a manglar no se ha documentado totalmente.Avian richness and diversity was recorded in the lagoons of Chacahua, Manialtepec and La Ventanilla, using counts and captures. Shannon-Wiener diversity was compared using the Hutcheson's t-test, similarity of species richness was determined, as were differences in abundance. Species accumulation curves were generated and richness was estimated using the Incidence-based Estimator. 17 orders, 39 families and 94 species were registered, 65 of which were resident and 25 of which were migratory. While no difference in abundance was detected (p > 0.05, there was difference in diversity between the lagoons, with La Ventanilla presenting the highest index (3.51. The greatest similarity obtained was between Chacahua and Manialtepec, with 56%, and the

  2. The Gyra washover fan in the Lefkada Lagoon, NW Greece—possible evidence of the 365 AD Crete earthquake and tsunami

    Science.gov (United States)

    May, Simon Matthias; Vött, Andreas; Brückner, Helmut; Smedile, Alessandra

    2012-10-01

    Coastal geomorphological and geological archives store valuable information about the geodynamic evolution of coastal areas and the contributing geomorphodynamic processes. The coastal geomorphology of the Lefkada- Preveza coastal zone, NW Greece, holds evidence for the influence of both gradual, low-energy and episodic, high-energy coastal processes. Situated close to the Hellenic Arc and the Cefalonia transform fault, the area belongs to one of the seismically most active regions in the Mediterranean. Thus, tsunami events are assumed to have contributed to the coastal evolution in the study area according to tsunami catalogues and field evidence from previous investigations. The northern part of the Lefkada Lagoon, separated from the Ionian Sea by an extensive barrier beach system, is characterized by a number of fan-like washover structures, formed by different washover generations. In this paper, we present detailed geomorphological, sedimentological, geochemical and foraminiferal investigations on the most prominent fan structure, the Gyra fan, based on terrestrial and lagoonal sediment cores. The Gyra fan consists of a coarse-grained sequence of fully marine origin on top of lagoonal mud and a palaeosol, respectively. The sequence shows numerous characteristics of extreme wave deposits. Due to the dimension and morphology of the fan, the existence of up to four consistent and correlative stratigraphic subunits, their landward thinning and their comparable sedimentary characteristics, we argue that a tsunami event induced the formation of the Gyra fan, comprising at least four major inundation impulses. According to radiocarbon dates, this geomorphological structure was most likely formed by teletsunami effects triggered by the 365 AD earthquake off western Crete.

  3. The effects of the 2004 tsunami on a coastal aquifer in Sri Lanka

    DEFF Research Database (Denmark)

    Vithanage, Meththika Suharshini; Engesgaard, Peter Knudegaard; Villholth, Karen G.

    2012-01-01

    on groundwater in coastal areas. Field investigations on the east coast of Sri Lanka were carried out along a transect located perpendicular to the coastline on a 2.4 km wide sand stretch bounded by the sea and a lagoon. Measurements of groundwater table elevation and electrical conductivity (EC...

  4. Primary production of phytoplankton in the estuaries of different types (by the example of the Curonian and Vistula Lagoons of the Baltic Sea and the Volga delta)

    Science.gov (United States)

    Aleksandrov, Sergei; Gorbunova, Julia

    2016-04-01

    The aim was to analyze the long-term change of the primary production in large estuaries of different types (Volga delta, Curonian and Vistula Lagoons) under the impact of environmental factors (e.g. climate changes, algal blooms, invasion mollusk). The researches (primary production, chlorophyll, nutrients and others) were carried out monthly from March-April to November in the Vistula and Curonian Lagoons since 1991 to 2015, and in the Lower part of the Volga Delta and fore-delta since 1996 to 2007. The Volga River is the largest river in Europe that flows into the Caspian Sea and it forms a great delta. According to the analysis of long-term data (from the 1960s), the maximum eutrophication and primary production (85-100 gCṡm-2ṡyear-1) in the Volga Delta was observed in the 1980s. In the 1990s, fertilizers use and the input of nutrients into the Volga Delta decreased significantly. Due of the high-flow exchange in the delta, especially during high-water years, observed in the 1980s - early 2000s, this led to a significant decrease in the concentration of nutrients in the water in the Volga Delta. As a result, in the 1990-2000s, the primary production has decreased to the level of 1960s-1970s (40-60 gCṡm-2ṡyear-1) and the process of eutrophication was replaced by de-eutrophication. At present, the trophic status of the Volga delta assessed as mesotrophic. The future trend of phytoplankton primary production of the Volga delta will greatly depend on the scenario of nutrients loading and river runoff. The Curonian Lagoon and Vistula Lagoon are the largest coastal lagoons of the Baltic Sea, relating to the most highly productive water bodies of Europe. The Curonian Lagoon is choke mostly freshwater lagoon, while the Vistula Lagoon is restricted brackish water lagoon. In the last decades the nutrients loading changes, warming trend and biological invasions are observed. The Curonian Lagoon may be characterized as hypertrophic water body. The local climate

  5. Universal service policy in Vietnam

    DEFF Research Database (Denmark)

    Do Manh, Thai; Falch, Morten; Von Salakpi, Simeon

    2016-01-01

    Universal service provision is a key to bridge the digital divide. This paper provides an empirical examination of the Vietnamese universal policy introduced in 2015 for implementation up to 2020. Using the framework of King et al. (1994) the paper analyses the universal services policy in Vietnam...... as well as the policies of broadband development in South Korea and Japan in order to clarify the types of universal service initiatives made in these countries. Furthermore, the paper compares the universal service policy in Vietnam with the broadband development policy in South Korea and in Japan...... in order to evaluate whether the Vietnamese universal policy is efficient. The paper concludes with a discussion of how an effective universal policy can be designed....

  6. COULD SALT WATER INTRUSION AND LAND SUBSIDENCE TRIGGER SOIL DESERTIFICATION IN THE CATCHMENT SOUTH OF THE VENICE LAGOON (ITALY)?

    OpenAIRE

    Tosi, Luigi; Teatini, Pietro; Strozzi, Tazio; Rizzetto, Federica; Carbognin, Laura; Putti, Mario

    2007-01-01

    The catchment south of the Venice Lagoon is threatened by shallow aquifer salinization and land subsidence. Although the area is not experiencing everywhere saline contamination and high sinking rates, a very serious situation has been brought to light in a large portion of the coastal farmland. The salt water contamination, recently investigated within a series of research projects, i.e. ISES, BRENTA, Co.Ri.La. 3.10-3.16, extends up to 20 km inland from the coast (Carbognin and Tosi, 2003; R...

  7. Geochemical behavior of heavy metals in differents environments in Rodrigo de Freitas lagoon - RJ/Brazil

    Directory of Open Access Journals (Sweden)

    Estefan M Fonseca

    2011-06-01

    Full Text Available The accelerated urbanisation without a planning, brought several environmental problems to Rio de Janeiro coastal zone, especially in areas such as Rodrigo de Freitas lagoon, which receives a great amount of untreated sewage every day. To assess the nature, potentially sources and extent of heavy metal pollution in the lagoon, sediments from the surrounding streets, from the entrance of the main canal that drains to the lagoon and from the bottom of the lagoon were collected and analysed by a modified selective extraction procedure in order to study the geochemical partitioning and bioavailability of Zn, Cu, Cr, Ni and Pb in these three compartments. The present study verified an increase in the Cu, Pb and Zn concentrations in the north of the Rodrigo de Freitas lagoon. Despite the different levels of oxidation between the sediments accumulated in the streets and in the bottom of the lagoon, the geochemical partitioning of the heavy metals did not show any pattern of variation for the metals, except for the element Cu. No concentrations were found in the soluble phase of samples collected in the surfacial sediments of the lagoon, suggesting no bioavailability of heavy metalsA urbanização acelerada, sem planejamento, resultou em uma série de problemas à zona costeira do Rio de Janeiro, especialmente em áreas como a Lagoa Rodrigo de Freitas, a qual recebe uma grande descarga de esgoto não tratado todos os dias. No intuito de avaliar a natureza, as fontes potenciais e a extensão da poluição por metais pesados na lagoa, sedimentos das ruas do entorno, das entradas do principal canal de drenagem e de superfície de fundo foram coletados. As análises se deram através de um método modificado de extração sequencial, com o objetivo de estudar o fracionamento geoquímico e a biodisponibilidade de Zn, Cu, Cr, Ni e Pb, nestes três compartimentos. O presente estudo verificou um aumento nas concentrações de Cu, Pb, e Zn no setor norte da

  8. Exchange rate determination in Vietnam

    OpenAIRE

    Thai-Ha Le

    2015-01-01

    This study investigates the determinants of the exchange rate in Vietnam and suggests policy implications. Gregory-Hansen cointegration tests and generalised variance decomposition (VDC) analysis were applied to monthly data from July 2004 to December 2013. The model was built based on the three popular approaches to exchange rate determination, which are purchasing power parity (PPP) approach, balance of payment (BOP) approach, and monetary and portfolio approach. This study finds that the p...

  9. Strongyloides stercoralis seroprevalence in Vietnam.

    Science.gov (United States)

    Diep, Nguyen Thi Ngoc; Thai, Pham Quang; Trang, Nghiem Nguyen Minh; Jäger, Julia; Fox, Annette; Horby, Peter; Phuong, Hoang Vu Mai; Anh, Dang Duc; Mai, LE Thi Quynh; VAN Doorn, H Rogier; Nadjm, Behzad

    2017-11-01

    Strongyloidiasis is a neglected tropical disease caused by the roundworm Strongyloides stercoralis affecting 30-100 million people worldwide. Many Southeast-Asian countries report a high prevalence of S. stercoralis infection, but there are little data from Vietnam. Here, we evaluated the seroprevalence of S. stercoralis related to geography, sex and age in Vietnam through serological testing of anonymized sera. Sera (n = 1710, 1340 adults and 270 children) from an anonymized age-stratified serum bank from four regions in Vietnam between 2012 and 2013 were tested using a commercial Strongyloides ratti immunoglobulin G ELISA. Seroreactivity was found in 29·1% (390/1340) of adults and 5·5% (15/270) of children. Male adults were more frequently seroreactive than females (33·3% vs. 24·9%, P = 0·001). The rural central highlands had the highest seroprevalence (42·4% of adults). Seroreactivity in the other regions was 29·9% (Hue) and 26·0% and 18·2% in the large urban centres of Hanoi and Ho Chi Minh City, respectively. We conclude that seroprevalence of S. stercoralis was high in the Vietnamese adult population, especially in rural areas.

  10. Acid Tar Lagoons: Management and Recovery

    Science.gov (United States)

    Bohers, Anna; Hroncová, Emília; Ladomerský, Juraj

    2017-04-01

    This contribution presents the issue with possibility of definitive removal of dangerous environmental burden in Slovakia - serious historical problem of two acid tar lagoons. In relation to their removal, no technology has been found so far - technologically and economically suitable, what caused problems with its management. Locality Predajná is well known in Slovakia by its character of contrasts: it is situated in the picturesque landscape of National Park buffer zone of Nízke Tatry, on the other site it is contaminated by 229 211m3 of acid tar with its characteristics of toxicity, carcinogenicity, teratogenicity, mutagenicity and toxicity especially for animals and plants. Acid tar in two landfills with depth of 1m in case of the first lagoon and 9,5m in case of the second lagoon is a waste product derived from operation of Petrochema Dubová - refinery and petrochemical plant whose activity was to process the crude oil through processes of sulfonation and adsorption technology for producing lubricating and special oils, synthetic detergents and special white oils for cosmetic and medical purposes. A part of acid tar was incinerated in two incineration plats. Concentration of SO2 in combustion gases was too high and it was not possible to decrease it under the value of 2000 mg.mn-3 [LADOMERSKÝ, J. - SAMEŠOVÁ, D.: Reduction in sulfur dioxide emissions waste gases of incineration plant. Acta facultatis ecologiae. 1999, p. 217-223]. That is why it was necessary to put them out of operation. Later, because of public opposition it was not possible to build a new incineration plat corresponding to the state of the art. Even though actual Slovak and European legislative for protection of environment against such impacts, neither of tried methods - bio or non-biologic treatment methods - was proved as suitable for processing or for recovery in the reason of different factors admission: i.e. strong aggressivity, difficulty with handling because of its sludgy and

  11. Sea-level rise and coastal groundwater inundation and shoaling at select sites in California, USA

    Science.gov (United States)

    Hoover, Daniel J.; Odigie, Kingsley; Swarzenski, Peter W.; Barnard, Patrick

    2017-01-01

    Study regionThe study region spans coastal California, USA, and focuses on three primary sites: Arcata, Stinson Beach, and Malibu Lagoon.Study focus1 m and 2 m sea-level rise (SLR) projections were used to assess vulnerability to SLR-driven groundwater emergence and shoaling at select low-lying, coastal sites in California. Separate and combined inundation scenarios for SLR and groundwater emergence were developed using digital elevation models of study site topography and groundwater surfaces constructed from well data or published groundwater level contours.New hydrological insights for the regionSLR impacts are a serious concern in coastal California which has a long (∼1800 km) and populous coastline. Information on the possible importance of SLR-driven groundwater inundation in California is limited. In this study, the potential for SLR-driven groundwater inundation at three sites (Arcata, Stinson Beach, and Malibu Lagoon) was investigated under 1 m and 2 m SLR scenarios. These sites provide insight into the vulnerability of Northern California coastal plains, coastal developments built on beach sand or sand spits, and developed areas around coastal lagoons associated with seasonal streams and berms. Northern California coastal plains with abundant shallow groundwater likely will see significant and widespread groundwater emergence, while impacts along the much drier central and southern California coast may be less severe due to the absence of shallow groundwater in many areas. Vulnerability analysis is hampered by the lack of data on shallow coastal aquifers, which commonly are not studied because they are not suitable for domestic or agricultural use. Shallow saline aquifers may be present in many areas along coastal California, which would dramatically increase vulnerability to SLR-driven groundwater emergence and shoaling. Improved understanding of the extent and response of California coastal aquifers to SLR will help in preparing for mitigation

  12. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil.

    Science.gov (United States)

    Silveira, T C L; Gama, A M S; Alves, T P; Fontoura, N F

    2016-04-19

    This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (-30.22, -50.55). The lagoon (19km2, maximum deep 2.5m) was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC), average granulometry (Avgran), and the percentage of sand (Pcsand). Prediction performance of Generalized Linear Models (GLM), Generalized Additive Models (GAM) and Boosted Regression Tree (BRT) were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis) was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  13. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil

    Directory of Open Access Journals (Sweden)

    T. C. L. Silveira

    Full Text Available Abstract This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (–30.22, –50.55. The lagoon (19km2, maximum deep 2.5m was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC, average granulometry (Avgran, and the percentage of sand (Pcsand. Prediction performance of Generalized Linear Models (GLM, Generalized Additive Models (GAM and Boosted Regression Tree (BRT were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  14. An integrated approach to prevent the erosion of salt marshes in the lagoon of Venice

    Directory of Open Access Journals (Sweden)

    Alberto Barausse

    2015-12-01

    Full Text Available The loss of coastal habitats is a widespread problem in Europe. To protect the intertidal salt marshes of the lagoon of Venice from the erosion due to natural and human causes which is diffusely and intensely impacting them, the European Commission has funded the demonstrative project LIFE VIMINE. LIFE VIMINE aims to protect the most interior, hard-to-access salt marshes in the northern lagoon of Venice through an integrated approach, whose core is the prevention of erosion through numerous, small but spatially-diffuse soil-bioengineering protections works, mainly placed through semi-manual labour and with low impact on the environment and the landscape. The effectiveness of protection works in the long term is ensured through routine, temporally-continuous and spatially-diffuse actions of monitoring and maintenance. This method contrasts the common approach to managing hydraulic risk and erosion in Italy which is based on large, one-off and irreversible protection actions. The sustainability of the LIFE VIMINE approach is ensured by the participatory involvement of stakeholders and the recognition that protecting salt marshes means defending the benefits they provide to society through their ecological functions, as well as protecting the jobs linked to the existence or conservation of this habitat.

  15. Spatial and temporal land cover changes in Terminos Lagoon Reserve, Mexico.

    Science.gov (United States)

    Soto-Galera, Ernesto; Piera, Jaume; López, Pilar

    2010-06-01

    Terminos Lagoon ecosystem is the largest fluvial-lagoon estuarine system in the country and one of the most important reserves of coastal flora and fauna in Mexico. Since the seventies, part of the main infrastructure for country's oil extraction is located in this area. Its high biodiversity has motivated different type of studies including deforestation processes and land use planning. In this work we used satellite image analysis to determine land cover changes in the area from 1974 to 2001. Our results indicate that tropical forest and mangroves presented the most extensive losses in its coverage. In contrast, urban areas and induced grassland increased considerably. In 2001 more than half of the ecosystem area showed changes from its original land cover, and a third part of it was deteriorated. The main causes of deforestation were both the increase in grassland and the growth of urban areas. However, deforestation was attenuated by natural reforestation and plant canopy recovery. We conclude that the introduction of cattle and urban development were the main causes for the land cover changes; however, the oil industry activity located in the ecosystem, has promoted indirectly to urban growth and rancher boom.

  16. Dynamics of Dissolved Oxygen in Relation to Saturation and Health of an Aquatic Body: A Case for Chilka Lagoon, India

    Directory of Open Access Journals (Sweden)

    B. S. R. V. Prasad

    2014-01-01

    Full Text Available Dissolved oxygen (DO is essential for an aquatic ecosystem since it controls the biological productivity. Here, we propose a unidimensional dynamic model for DO by incorporating biological (photosynthesis, respiration, and mineralization, physical (atmospheric reaeration and chemical (nitrification processes so characteristic of shallow coastal water bodies. The analytical study of the proposed model is focussed on supersaturation and undersaturation of oxygen in the water body. The controllability of the ecosystem health has also been investigated. Model results indicate that, while undersaturation of oxygen is largely governed by nitrification and Net Ecosystem Metabolism (NEM, the supersaturation is controlled by photosynthetic activity. The model results are corroborated with observed data collected from Chilka lagoon, India. Subsequently, a biogeochemical model to study the DO variations in Chilka lagoon has been constructed. The model is properly calibrated and validated with observed data. Two independent sets of data (2004-2005 and 2005-2006 were used for model calibration and validation and Chi-square tests supported its robustness (R2=0.982 and 0.987; P<0.05. The model was used to evaluate independently the influence of individual taxa (diatoms, microphytobenthos, and cyanophyceans on DO variations. Simulations indicate the vital role of microphytobenthos in lagoon DO dynamics and the overall wellbeing.

  17. Inhomogeneity of methane emissions from a dairy waste lagoon.

    Science.gov (United States)

    Grant, Richard H; Boehm, Matthew T

    2015-11-01

    Methane (CH4) is the dominant greenhouse gas emitted by animal agriculture manure. Since the gas is relatively insoluble in water, it is concentrated in discrete bubbles that rise through waste lagoons and burst at the surface. This results in lagoon emissions that are inhomogeneous in both space and time. Emissions from a midwestern dairy waste lagoon were measured over 2 weeks to evaluate the spatial homogeneity of the source emissions and to compare two methods for measuring this inhomogeneous emission. Emissions were determined using an inverse dispersion model based on CH4 concentrations measured both by a single scanning tunable diode laser (TDL) aimed at a series of reflectors and by flame ionization detection (FID) gas chromatography on line-sampled air. Emissions were best estimated using scanned TDL concentrations over relatively short optical paths that collectively span the entire cross-wind width of the source, so as to provide both the best capture of discrete plumes from the bursting bubbles on the lagoon surface and the best detection of CH4 background concentrations. The lagoon emissions during the study were spatially inhomogeneous at hourly time scales. Partitioning the inhomogeneous source into two source regions reduced the estimated emissions of the overall lagoon by 57% but increased the variability. Consequently, it is important to assess the homogeneity of a source prior to measurements and final emissions calculation. Plans for measuring methane emissions from waste lagoons must take into account the spatial inhomogeneity of the source strength. The assumption of emission source homogeneity for a low-solubility gas such as CH4 emitted from an animal waste lagoon can result in significant emission overestimates. The entire breadth and length of the area source must be measured, preferably with multiple optical paths, for the detection of discrete plumes from the different emitting regions and for determining the background concentration

  18. Teaching the Vietnam War: A Sociological Approach.

    Science.gov (United States)

    Starr, Jerold M.

    1995-01-01

    Maintains that, because of its importance in modern U.S. history, over 300 college courses are taught on the Vietnam War. Asserts that studying the war helps students develop critical thinking skills needed for citizenship. Describes the texts, formats, and assignments used in a college sociology course on the Vietnam War. (CFR)

  19. A Century of changes for Razelm-Sinoe Lagoon System

    Science.gov (United States)

    Scrieciu, Marian-Albert; Stanica, Adrian

    2014-05-01

    A Century of changes for Razelm-Sinoe Lagoon System Marian-Albert Scrieciu (a), Adrian Stanica (a) (a) National Institute of Marine Geology and Geoecology e GeoEcoMar, Str. Dimitrie Onciul 23e25, Sector 2, 024053 Bucharest, Romania Razelm-Sinoe Lagoon System, situated in the NW part of the Black Sea, in tight connection with the Danube Delta, has been subject to major changes due to human interventions in the past century. These changes have resulted into a complete change of the Lagoon specific ecosystems compared to its pristine state. In its natural state, as brackish - transitional environment, Antipa (1894) mentions Razelm Lagoon as one of the places with the greatest fisheries around the Black Sea coast (about 1879 - 1884, there were approximately 10,000 fishermen, all working on the Razelm Sinoe Lagoon System). Starting with the end of the XIXth Century, new canals were dug and existing channels were dredged in order to develop tighter connections with the Danube River. The natural inlet of Portita was blocked four decades ago and connections between the various parts of the lagoon system were controlled by the building of locks and sluices. The 2 inlets of Sinoe Lagoon were also controlled during early 1980s. Under these conditions, the lagoon ecosystem changed from brackish towards freshwater, with major effects on the existing flora and fauna. The period of brutal interventions ended in 1989 and the Razelm-Sinoe Lagoon System became part of the Danube Delta Biosphere Reserve in 1991, with a strict policy of nature protection and restoration. Spatial planning has been the major management option for the entire reserve, lagoon system included. Plans for sustainable development of the Razelm-Sinoe Lagoon System have been built in a participative manner, involving the local stakeholders, as part of FP7 ARCH project. Special attention has been given to impacts of climate change. The study presents the vision for the development Razelm-Sinoe Lagoon System over

  20. Biological components of Greek lagoonal ecosystems: an overview

    Directory of Open Access Journals (Sweden)

    A. NICOLAIDOU

    2005-12-01

    Full Text Available The paper summarises the available information on the main biological components – phytoplankton, zooplankton, phytobenthos, zoobenthos and fish – of Greek lagoonal ecosystems. Meiobenthos was also studied in one of the lagoons. All components show great variability both in space and time, which is attributed to the variability of environmental conditions. The most important variable influencing species distribution and diversity is the degree of communication with the sea and the nutrient load introduced through fresh water inputs. Certain new methods, which have been applied for evaluation of the ecological quality state of the lagoons, are also presented.

  1. Cadmium assessment on the intertidal water margins from the Óbidos Lagoon (western coast of Portugal

    Directory of Open Access Journals (Sweden)

    Marcia S.S. Santos

    2014-04-01

    Full Text Available The Óbidos Lagoon is the largest shallow coastal lagoon in Portugal. Like any other brackish water system, it has been potentially exposed to different sources of contamination (e.g. livestock farming, domestic and industrial sewage. Trace metals are persistent elements present in the water and sediments in their elemental and organic/inorganic forms. In fact, Cadmium is extremely pollutant due to its great solubility in water and high toxicity for organisms. Also, it is classified as a priority substance according to the European Union Water Frame directive. In this context, a seasonal environmental monitoring program was implemented in the intertidal water margins of the Óbidos Lagoon to assess the presence of Cadmium. In 2009 and 2010, eight sampling stations (S distributed on the shores of the Óbidos Lagoon were chosen and water and sediments were seasonally collected. In all samples, cadmium concentrations were analyzed by Atomic Absorption Spectrometry, with Graphite Furnace Technique. Cadmium dissolved in the water samples was only detected during summer months, with the highest values in the Barrosa’s arm (S3: 0.35 mg/l in 2009, and at the station further downstream (S1: 0.19 mg/l in 2010. In the suspended fraction of the water samples the trace metal was detectable in all seasons, with the maximum concentration at the Barrosa’s arm (S4: 1.04 mg/l in the winter of 2010. Cadmium was not detectable in the sediments during the summers and was sporadically present in the autumn and in the winter of 2009. The highest concentration in the sediments was observed at the Barrosa´s arm (S4: 140.78 mg/kg in the spring of 2010. As a whole, cadmium contamination appears to be mostly focused on the inner areas of the lagoon, at the Barrosa´s arm, but a clear seasonal pattern of variation was not detectable. These results allow a better understanding of the environmental quality of this ecosystem and may assist in the definition of coastal

  2. The dominance of cyanobacteria in Mediterranean hypereutrophic lagoons: a case study of Cabras Lagoon (Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    Silvia Pulina

    2011-02-01

    Full Text Available An intense proliferation of cyanobacteria in Cabras Lagoon was investigated over a period of two years (July 2007 to June 2009. The influence of environmental and meteorological parameters in the lagoon on temporal variations in cyanobacteria orders was assessed. For 17 months, Chroococcales was the only cyanobacterial order observed in the lagoon. Cyanobium-type cells (Reynolds functional group Z were the most abundant phytoplankton taxon during this period. In the following months, drastic changes in the cyanobacteria assemblages occurred simultaneously with constant, intense rainfall that led to a sudden drop in the lagoon’s salinity. The succession of autumn–winter Oscillatoriales (Planktothrix sp. and Pseudanabaena catenata; Reynolds functional group S1 and late spring growth of Nostocales (Aphanizomenon gracile, Aphanizomenon aphanizomenoides, and Anabaenopsis circularis; Reynolds functional group H1 was monitored. Canonical Correspondence Analysis was carried out to quantify the influence of environmental variables, and indicated strong relationships between Chroococcales and salinity, Oscillatoriales and higher values of SRP and the DIN/SRP ratio, and Nostocales and lower nutrient concentrations, the DIN/SRP ratio and salinity.

  3. Ship-induced solitary Riemann waves of depression in Venice Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Parnell, Kevin E. [College of Marine and Environmental Sciences and Centre for Tropical Environmental and Sustainability Sciences, James Cook University, Queensland 4811 (Australia); Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Soomere, Tarmo, E-mail: soomere@cs.ioc.ee [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn (Estonia); Zaggia, Luca [Institute of Marine Sciences, National Research Council, Castello 2737/F, 30122 Venice (Italy); Rodin, Artem [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Lorenzetti, Giuliano [Institute of Marine Sciences, National Research Council, Castello 2737/F, 30122 Venice (Italy); Rapaglia, John [Sacred Heart University Department of Biology, 5151 Park Avenue, Fairfield, CT 06825 (United States); Scarpa, Gian Marco [Università Ca' Foscari, Dorsoduro 3246, 30123 Venice (Italy)

    2015-03-06

    We demonstrate that ships of moderate size, sailing at low depth Froude numbers (0.37–0.5) in a navigation channel surrounded by shallow banks, produce depressions with depths up to 2.5 m. These depressions (Bernoulli wakes) propagate as long-living strongly nonlinear solitary Riemann waves of depression substantial distances into Venice Lagoon. They gradually become strongly asymmetric with the rear of the depression becoming extremely steep, similar to a bore. As they are dynamically similar, air pressure fluctuations moving over variable-depth coastal areas could generate meteorological tsunamis with a leading depression wave followed by a devastating bore-like feature. - Highlights: • Unprecedently deep long-living ship-induced waves of depression detected. • Such waves are generated in channels with side banks under low Froude numbers. • The propagation of these waves is replicated using Riemann waves. • Long-living waves of depression form bore-like features at rear slope.

  4. Silica in invasive wetland plant species of lagoons, Côte d'Ivoire: Spatio-temporal patterns

    Science.gov (United States)

    José-mathieu Koné, Yéfanlan; Schoelynck, Jonas

    2017-04-01

    Tropical wetlands are known to accumulate a large quantity of Biogenic Silica (BSi) produced by wetland plant species (Struyf et al., 2015), and approximately 70-80% of the total supply of Dissolved Si (DSi) to the coastal zone occurs in (sub) tropical river systems (Jennerjahn et al. 2006). However, the data at these latitudes are limited. Here, we present the BSi concentration from eleven invasive macrophyte species randomly collected in three small ( 800ha) lagoons of Côte d'Ivoire during 12 months. Our data showed a large spatio-temporal variability of BSi in the three lagoons with no consistent trends. In general, the BSi concentrations obtained were high and values ranged from 0 to 54 mg g-1 through the entire sampling period, with the highest values found in Acroceras zizaniodes (emergent species of Poaceae). In general, free floating species had significantly less BSi than emergent species (Pyoung stage were similar to those found in the emergent species. Based on yearly averages, highest BSi values were observed in Kodjoboué lagoon, and the lowest in the Ono lagoon that is 80% covered by macrophytes. Moreover, the dissolved silica (DSi) concentrations were systematically higher in Ono Lagoon than in Kodjoboué Lagoon. We conclude that in an eutrophic system Si accumulating in aquatic macrophytes is not related to Si availability but to other environmental factors. Jennerjahn, T.C., Knoppers, B.A., de Souze, W.F.L., Brunskill, G.J., Silva, E.I.L., Adi, S. et al., 2006. Factors controlling dissolved silica in tropical rivers. In: Ittekot, V. (ed) The silicon cycle. Island Press, Washington, D. C, pp 29-51 Schoelynck J and Struyf E, 2016. Silicon in aquatic vegetation. Functional Ecology. 30: 1323-1330. Struyf, E., Mosimane, K., Van Pelt, D., Murray-Hudson, M., Meire, P., Frings, P., Wolski, P., Schaller, J., Gondwe, M.J., Schoelynck, J. and Conley, D.J., 2015. The role of vegetation in the Okavango Delta silica sink. Wetlands, 5: 171-181.

  5. Human impact and the historical transformation of saltmarshes in the Marano and Grado Lagoon, northern Adriatic Sea

    Science.gov (United States)

    Fontolan, Giorgio; Pillon, Simone; Bezzi, Annelore; Villalta, Renato; Lipizer, Marco; Triches, Antonella; D'Aietti, Alessandro

    2012-11-01

    Historical transformations of the saltmarshes in the six sub-basins of the Marano and Grado Lagoon were analyzed using aerial photographs (1954, 1990, 2006), and the support of historical maps and topographic surveys. Analysis of the 2006 set of aerial photographs enabled the definition of the present extent and distribution of the saltmarshes inside the lagoon (760 ha), with a total reduction in saltmarsh area of 16% (144 ha) compared to 1954. Direct human actions played a significant role in the budget, since total loss due to land reclamation and dredging during this period amounted to 126 ha. After excluding the total loss due to direct human interventions, different erosional and depositional marsh types were recognized and associated with different forcing factors, based on morphological and geographical evidence. Over the 52-year period marshes were lost due to: (a) drowning - the combined effects of eustatism, regional subsidence and autocompaction (102 ha); (b) edge-retreat by wind wave attack (34 ha); (c) erosion by vessel-generated waves (37 ha); and (d) coastal dynamics and inlet migration (5.7 ha). Conversely, marshes gained in area due to: (a) fluvial input (63 ha); (b) tidal input (27 ha); (c) paralagoonal deposition (45 ha); (d) the re-opening of abandoned fish farms (18 ha); and (e) the dumping of dredged material (8 ha). Our analysis demonstrates that local and short-term forcing factors can obliterate or compensate the long-term ones, especially the relative sea-level rise. A test of the integrated sediment budget carried out on one third of the total lagoon, through a bathymetric comparison between datasets from 1964 to 2009, pointed out that conservation or slight expansion of the marshes inside these basins were linked to an overall positive sediment budget of 61,000 m3/y. Nevertheless, significant morphological changes occurred in the submerged basin, which is affected by sustained deposition along the inner margins due to sediment supplies

  6. Spatial assessment of radiocaesium in the largest lagoon in Fukushima after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident.

    Science.gov (United States)

    Kambayashi, Shota; Zhang, Jing; Narita, Hisashi

    2017-09-15

    Radionuclides deposited on land by global fallouts and nuclear power station accidents spread over coastal environments through estuarine areas connecting land to ocean. In this study, we monitored activity concentration of radiocaesium in surface sediment and re-suspended particles in Matsukawa-ura lagoon, the largest lagoon in Fukushima, after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident. Radiocaesium distribution in surface sediment varied spatiotemporally and irregularly due to the effect of tidal waves. The effective half-life was significantly shorter than physical half-life, suggesting some system of radiocaesium discharge in the lagoon. Sediment trap observation revealed re-suspended particles from sediment were transported to the ocean. For these reasons, it is suggested that re-suspension of particles in the lagoon and their transportation to the ocean by the seawater exchange process are important processes of radiocaesium discharge. Moreover, our results show that seawater exchange process contributes to the dispersion of radiocaesium in the ocean. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Hydrological data concerning submarine groundwater discharge along the western margin of Indian River Lagoon, east-central Florida - December 2016 and January 2017

    Science.gov (United States)

    McCloskey, Terrence A.; Smith, Christopher G.; Zaremba, Nicholas; McBride, Elsie; Everhart, Cheyenne

    2017-01-01

    Indian River Lagoon, one of the most biologically diverse estuarine systems in the continental United States, is a shallow brackish lagoon stretching along approximately 200 kilometers (km) of the Atlantic coast of central Florida. Lagoon width varies from ~0.5 – 9.0 km, with substantial human infrastructure lining both shores. Scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center investigated submarine groundwater discharge at Eau Gallie North, a site along the western shore in the central section of the lagoon, using continuous resistivity profiling (CRP). The CRP array was towed behind a boat along five shore-parallel transects located ~125, 200, 350, 500 and 750 meters offshore and traversing ~1.5 km along north-south transects. Each transect was given a track name (EB., EC., ED., EE., and EF.) and lines were run both north to south and south to north. Repetitive profiles will be conducted along these same tracks, at various times, in order to determine temporal variability. As resistivity is a function of both geology and salinity, temporal changes will reflect salinity changes, as the underlying geology will be presumed to remain constant. Resistivity data were assigned geographic coordinates and water depth values, in order to produce modeled resistivity, accounting for salinity and geologic parameters.  This data release provides the raw resistivity, geographical and water parameter data collected in December 2016 and January 2017.

  8. VISTA Stares Deeply into the Blue Lagoon

    Science.gov (United States)

    2011-01-01

    This new infrared image of the Lagoon Nebula was captured as part of a five-year study of the Milky Way using ESO's VISTA telescope at the Paranal Observatory in Chile. This is a small piece of a much larger image of the region surrounding the nebula, which is, in turn, only one part of a huge survey. Astronomers are currently using ESO's Visible and Infrared Survey Telescope for Astronomy (VISTA) to scour the Milky Way's central regions for variable objects and map its structure in greater detail than ever before. This huge survey is called VISTA Variables in the Via Lactea (VVV) [1]. The new infrared image presented here was taken as part of this survey. It shows the stellar nursery called the Lagoon Nebula (also known as Messier 8, see eso0936), which lies about 4000-5000 light-years away in the constellation of Sagittarius (the Archer). Infrared observations allow astronomers to peer behind the veil of dust that prevents them from seeing celestial objects in visible light. This is because visible light, which has a wavelength that is about the same size as the dust particles, is strongly scattered, but the longer wavelength infrared light can pass through the dust largely unscathed. VISTA, with its 4.1-metre diameter mirror - the largest survey telescope in the world - is dedicated to surveying large areas of the sky at near-infrared wavelengths deeply and quickly. It is therefore ideally suited to studying star birth. Stars typically form in large molecular clouds of gas and dust, which collapse under their own weight. The Lagoon Nebula, however, is also home to a number of much more compact regions of collapsing gas and dust, called Bok globules [2]. These dark clouds are so dense that, even in the infrared, they can block the starlight from background stars. But the most famous dark feature in the nebula, for which it is named, is the lagoon-shaped dust lane that winds its way through the glowing cloud of gas. Hot, young stars, which give off intense

  9. Nutrient removal from swine lagoon effluent by duckweed

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, B.A.; Cheng, J.; Classen, J.; Stomp, A.M.

    2000-04-01

    Three duckweed geographic isolates were grown on varying concentrations of swine lagoon effluent in a greenhouse to determine their ability to remove nutrients from the effluent. Duckweed biomass was harvested every other day over a 12-day period. Duckweed biomass production, nutrient loss from the swine lagoon effluent, and nutrient content of duckweed biomass were used to identify effluent concentrations/geographic isolate combinations that are effective in terms of nutrient utilization from swine lagoon effluent and production of healthy duckweed biomass. When Lemna minor geographic isolate 8627 was grown on 50% swine lagoon effluent, respective losses of TKN, NH{sub 3}-N, TP, OPO{sub 4}-P, TOC, K, Cu, and Zn were 83, 100, 49, 31, 68, 21, 28 and 67%.

  10. Sea-level rise and coastal groundwater inundation and shoaling at select sites in California, USA

    Directory of Open Access Journals (Sweden)

    Daniel J. Hoover

    2017-06-01

    New hydrological insights for the region: SLR impacts are a serious concern in coastal California which has a long (∼1800 km and populous coastline. Information on the possible importance of SLR-driven groundwater inundation in California is limited. In this study, the potential for SLR-driven groundwater inundation at three sites (Arcata, Stinson Beach, and Malibu Lagoon was investigated under 1 m and 2 m SLR scenarios. These sites provide insight into the vulnerability of Northern California coastal plains, coastal developments built on beach sand or sand spits, and developed areas around coastal lagoons associated with seasonal streams and berms. Northern California coastal plains with abundant shallow groundwater likely will see significant and widespread groundwater emergence, while impacts along the much drier central and southern California coast may be less severe due to the absence of shallow groundwater in many areas. Vulnerability analysis is hampered by the lack of data on shallow coastal aquifers, which commonly are not studied because they are not suitable for domestic or agricultural use. Shallow saline aquifers may be present in many areas along coastal California, which would dramatically increase vulnerability to SLR-driven groundwater emergence and shoaling. Improved understanding of the extent and response of California coastal aquifers to SLR will help in preparing for mitigation and adaptation.

  11. Isolation and genetic characterization of Nocardia seriolae from snubnose pompano Trachinotus blochii in Vietnam.

    Science.gov (United States)

    Vu-Khac, Hung; Duong, Van Quy; Chen, Shih-Chu; Pham, Trung Hieu; Nguyen, Thi Thu; Trinh, Thi Thu

    2016-07-07

    A total of 480 cage-cultured fish were collected from 4 coastal provinces in central Vietnam to investigate the causative agent of nocardiosis. Fish displayed unique characteristics such as paleness and lethargy and exhibited haemorrhages and ulcers on the skin. Prominent white nodules varying in size were observed in the spleen, kidney, and liver. Furthermore, histopathological sections showed typical granulomatous lesions in these organs. Using the Ziehl-Neelsen staining method, isolated bacteria exhibited acid-fast, bead-like filament morphology when cultured in brain-heart infusion medium or Ogawa medium. Phylogenetic analysis of 16S rDNA confirmed that the isolated bacterium was Nocardia seriolae. This study demonstrates for the first time an outbreak of N. seriolae in snubnose pompano in central Vietnam.

  12. Geological evolution, regional perspectives and hydrocarbon potential of the northwest Phu Khanh Basin, offshore Central Vietnam

    DEFF Research Database (Denmark)

    Fyhn, Michael Bryld Wessel; Nielsen, Lars H.; Boldreel, Lars Ole

    2009-01-01

      Seismic stratigraphic and structural analyses of the northwest Phu Khanh Basin, offshore Central Vietnam, based on 2-D seismic data, indicate that the initial rifting began during the latest Cretaceous? or Palaeogene controlled by left-lateral transtension along the East Vietnam Boundary Fault...... seeps are found at Dam Thi Nai, immediately landward of the basin. Geochemical analyses of the oil seeps indicate the existence of at least two early to peak mature source rocks. Maturation modelling, combined with the seismic analysis, suggests the likely presence of oil kitchens 40-50km downdip...... in the basin, and a fairly simple oil migration route. The basin is probably charged from lacustrine syn-rift mudstones, humic coals and fore-reef marls. Potential reservoirs are turbidite, lowstand delta, shelf and coastal sandstones, as well as platform and reef carbonates and fractured basement. Various...

  13. Neurology in the Vietnam War.

    Science.gov (United States)

    Gunderson, Carl H; Daroff, Robert B

    2016-01-01

    Between December 1965 and December 1971, the United States maintained armed forces in Vietnam never less than 180,000 men and women in support of the war. At one time, this commitment exceeded half a million soldiers, sailors, and airmen from both the United States and its allies. Such forces required an extensive medical presence, including 19 neurologists. All but two of the neurologists had been drafted for a 2-year tour of duty after deferment for residency training. They were assigned to Vietnam for one of those 2 years in two Army Medical Units and one Air Force facility providing neurological care for American and allied forces, as well as many civilians. Their practice included exposure to unfamiliar disorders including cerebral malaria, Japanese B encephalitis, sleep deprivation seizures, and toxic encephalitis caused by injection or inhalation of C-4 explosive. They and neurologists at facilities in the United States published studies on all of these entities both during and after the war. These publications spawned the Defense and Veterans Head Injury Study, which was conceived during the Korean War and continues today as the Defense and Veterans Head Injury Center. It initially focused on post-traumatic epilepsy and later on all effects of brain injury. The Agent Orange controversy arose after the war; during the war, it was not perceived as a threat by medical personnel. Although soldiers in previous wars had developed serious psychological impairments, post-traumatic stress disorder was formally recognized in the servicemen returning from Vietnam. © 2016 S. Karger AG, Basel.

  14. Lake Superior Coastal Wetland Fish Assemblages and ...

    Science.gov (United States)

    The role of the coastal margin and the watershed context in defining the ecology of even very large lakes is increasingly being recognized and examined. Coastal wetlands are both important contributors to the biodiversity and productivity of large lakes and important mediators of the lake-basin connection. We explored wetland-watershed connections and their relationship to wetland function and condition using data collected from 37 Lake Superior wetlands spanning a substantial geographic and geomorphic gradient. While none of these wetlands are particularly disturbed, there were nevertheless clear relationships between watershed landuse and wetland habitat and biota, and these varied consistently across wetland type categories that reflected the strength of connection to the watershed. For example, water clarity and vegetation structure complexity declined with decreasing percent natural land cover, and these effects were strongest in riverine wetlands (having generally large watersheds and tributary-dominated hydrology) and weakest in lagoon wetlands (having generally small watersheds and lake-dominate hydrology). Fish abundance and species richness both increased with decreasing percent natural land cover while species diversity decreased, and again the effect was strongest in riverine wetlands. Lagoonal wetlands, which lack any substantial tributary, consistently harbored the fewest species of fish and a composition different from the more watershed-lin

  15. A geochemical analytical approach for the evaluation of heavy metal distribution in lagoon sediments

    Energy Technology Data Exchange (ETDEWEB)

    Pacifico, R.; Cremisini, C.; Spaziani, F. [ENEA, Centro Ricerche Casaccia, Sez. PROT-CHIM, Roma (Italy); Adamo, P. [Univ. di Napoli Federico II, Portici (Italy). Dipt. di Scienze del Suolo, della Pianta, dell' Ambiente e delle Produzioni Animali; Ferrara, L. [Univ. di Napoli Federico II, Napoli (Italy). Dipt. di Chimica

    2007-10-15

    Background, Aim and Scope: Italian lagoon environments are of great importance due either to their frequency and distribution along the coasts or to their management. Agriculture, urban and industrial activities in lagoon catchments can be sources of heavy metal (HM) pollution by direct waste dumping, atmospheric deposition of fumes or, simply, as a consequence of a lack of natural water recharge. HM concentration in lagoon sediments is a tool of HM monitoring in the surrounding environment. Application of sequential extraction procedures (SEP) to sediments makes it possible to study the HM distribution among the main geochemical phases and to assess their potential mobilization as a consequence of environmental condition variations. In the present study, the three-step SEP (0.11 M HOAc; 0.1 M NH{sub 2}OH.HCl; 8.8 M H{sub 2}O{sub 2} and then 1 M NH{sub 4}OAc), developed by the Measurement and Testing Programme of the European Commission (BCR), was combined with information on the chemical and mineralogical properties of the sediments in order to assess the level and risk of mobility of HM (Cu, Cr, Cd, Pb, Ni, Zn) in sediments from the Fusaro volcanic coastal lagoon of southern Italy. The effect of sediment air drying and physico-chemical properties on the metal distribution in various geochemical forms and fractions was considered. Materials and Methods: Surface (5 cm depth) sediment samples were collected from twenty-one sites on the Fusaro lagoon. Moisture, pH, organic carbon, carbonates, particle-size distribution and HM total content were determined on the dried sediment samples. The mineralogy of the clay fraction was determined at room temperature on random and oriented samples. The different forms of Al, Si and Fe in the bulk sediment (< 2 mm) were analyzed after oxalate, dithionite-citrate and pyrophosphate extractions. The BCR-SEP was used to fractionate trace element chemical forms in nine selected sediment samples. Effects of sediment air-drying on HM

  16. Cancer incidence in Australian Vietnam veterans

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, E.; Horsley, K. [Australian Government Department of Veterans' Affairs (Australia); Hoek, R. van der [Australian Institute of Health and Welfare (Australia)

    2004-09-15

    Australian Defence Force (ADF) personnel participated in the Vietnam Conflict from 1962 to 1973, involving nearly 60,000 personnel, of whom over 500 died during service and 3131 were severely physically wounded. Service in the Vietnam conflict presented distinct health challenges. Besides the hazards of combat conditions for extended periods, herbicides and other toxic chemicals were used extensively. The United States military sprayed more than 76,000,000L of herbicide over Vietnam in their Air Force Ranch Hand and Operation Trail Dust programs. The most heavily used herbicide was Agent Orange, contaminated with 2,3,7,8-tetrachlorodibenzo-pdioxin. Since the Vietnam conflict, ex-Service organisations (ESOs) have maintained that Vietnam service adversely affected the health of veterans. Initial studies showed no excess risk attributable to their service. However, more recent studies have shown that Vietnam veterans have excess incidence and mortality rates from several conditions such as cancers and heart disease. This paper describes the first cancer incidence study for all ADF Vietnam veterans.

  17. Macrobenthic community changes due to dystrophic events and freshwater inflow: Changes in space and time in a Mediterranean lagoon (Gialova lagoon, SW Greece)

    Science.gov (United States)

    Chatzigeorgiou, Georgios; Reizopoulou, Sophia; Maidanou, Maria; Naletaki, Maria; Orneraki, Eleni; Apostolaki, Eugenia; Arvanitidis, Christos

    2011-07-01

    This paper considers the hypothesis that changes in community structure through the control of the larvae maintenance and of the biological traits of the species mostly contribute to the spatio-temporal community pattern. This is supported by the results of the study, the changes to the macrobenthic community pattern deriving from two sampling periods in Gialova lagoon (SW Greece), carried out on a seasonal basis for two yearly periods: 1994-95 and 1998-99. Cognetti's hypothesis that populations of the tolerant species occupying coastal marine habitats may belong to different species is another alternative hypothesis still to be tested. The importance of alternative management plans aiming at the amelioration of the hydrodynamic conditions of the lagoons and supported by continuous scientific monitoring is highlighted. Two canals bringing fresh water were opened at the beginning of the second sampling period, an intervention among others, suggested by the management plan proposed after the end of the first sampling period. The results show considerable variations in the values of the key environmental variables, for instance long periods with negative Redox potential values, decreased salinity and increased concentrations of the particulate organic matter and of the nutrients. The variables were correlated with the spatio-temporal community pattern, characterized during the second sampling period by: (i) greater dissimilarities among stations/seasons; (ii) disruption of the periodic trend observed on the seasonal scale; (iii) larger relative dissimilarities among the patterns stemming from the macrobenthos and the most abundant groups (polychaetes, molluscs, crustaceans); (iv) significant decrease in abundance or even the disappearance of several marine origin species, along with increased abundance in a few brackish-water species. All of the above changes in the community pattern are considered as early warning signals leading towards degradation, which has not

  18. Impact of nutrient enrichment and fish introductions on the structure and function of experimental shallow littoral lagoons

    Directory of Open Access Journals (Sweden)

    Oriol Cano-Rocabayera

    2015-12-01

    Full Text Available Mediterranean coastal lagoons are probably one of the most singular and endangered ecosystems worldwide. Common threats to other aquatic ecosystems are nutrient enrichment and species introductions. In shallow and warm areas, the environmental concern may be even exacerbated by an increase in nutrient levels and biotic interactions due to the low water flow, coupled to the temperature-sensitivity of ectotherms’ metabolism and hence ecological processes. Nutrient enrichment can benefit ecosystem productivity when the bottom-up effect of nutrients is counteracted by top-down controllers such as macro-invertebrates and/or fish. This balance can, however, be directly and indirectly disrupted by excessive fertilization and/or the release of exotic species. Ammonia and nitrite has long been considered a water quality hazard but the toxic effects of nitrates are still poorly studied. The present study examined experimentally the multi-trophic impacts of chronic nitrate exposure and/or the invasive eastern mosquitofish (Gambusia holbrooki on the structure and function of shallow littoral lagoons. Specifically, we monitored ecosystem metabolism (primary production and leaf litter decomposition and the community structure of pelagic and benthonic macro-invertebrates during 2 months. Preliminary results show that chronic nitrate pollution and/or G. holbrooki can profoundly alter the structure and function of coastal lagoon ecosystems, and that pelagic and benthonic sub-systems are coupled in response to these anthropogenic stressors. Although the long-term consequences of these findings remain to be examined in detail, this study will increase our mechanistic understanding of how the top-down and bottom-up controllers of aquatic ecosystems are affected by major drivers of global change typified by nitrate pollution and an invasive species.

  19. Seychelles Lagoon Provides Corals with a Refuge from Bleaching

    Directory of Open Access Journals (Sweden)

    David Iluz

    2008-01-01

    Full Text Available An extensive bleaching event in the summer of the year 1997-1998 affected most reefs along East Africa's shores. In the aftermath of that episode, the reefs of Île Alphonse in the Seychelles were examined and it was found that reefs along the seaward slopes of the island lost >95% of their branching coral colonies, with considerably higher survival of massive species. Île Alphonse features a nearly circular shallow lagoon, with steep seaward slopes. Contrary to our expectations, mortality in the warmer lagoon was far lower than of coral colonies on the surrounding slopes, bathed in deeper and cooler waters. We suggest that corals in the lagoon were protected from UV radiation by leachate stemming from seagrass leaves steeped in the lagoon. Our measurements in the lagoon showed a strong attenuation of ultraviolet radiation, not observed in the waters outside the lagoon, and laboratory examination confirmed that the strong UV absorption of substances leached into seawater from decomposing leaves of the seagrass Thalassodendron (=Cymodocea testudinaceum. Our findings demonstrate the synergism between elevated seawater temperature and UV radiation in triggering bleaching on shallow reefs.

  20. Abundance of bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae, inhabiting the Patos Lagoon estuary, southern Brazil: implications for conservation

    Directory of Open Access Journals (Sweden)

    Pedro F Fruet

    2011-02-01

    Full Text Available A new mark-recapture abundance estimate and a photographic census were carried out to investigate the possible decline in the abundance of the bottlenose dolphins, Tursiops truncatus (Montagu, 1821, in the Patos Lagoon estuary due to the high levels of bycatch mortality which occurred between 2002 and 2006 in oceanic coastal areas close to the estuary. Fourteen systematic boat surveys were conducted between August and early December 2005 to photo-identify the bottlenose dolphins. The estimated number of animals, with long-lasting marks, in the population obtained from Chapman's and Mth models were 51 (95% CI = 49-53 and 52 (95% CI = 51-60, respectively. Taking into account the proportion of dolphins with long-lasting marks in the population, the total estimated population size ranged between 84 (95% CI = 76-93 and 86 (95% CI = 78-95 individuals, respectively, which was very similar to the 84 individuals revealed by the population census. Our results did not differ from the abundance estimate carried out in 1998, prior to the high fishing-related mortality event, suggesting that the population is stable. Plausible argument to explain the stability of the population is that some carcasses found on the oceanic coastal beaches near Patos Lagoon estuary come from animals that do not belong to the estuary community. Future studies should investigate fine-scale habitat partition between estuarine and adjacent coastal dolphins. If the existence of different communities living in close proximity (estuarine and coastal areas near to the estuary is confirmed, a new abundance estimate is needed to access the conservation status of bottlenose dolphins in this region.

  1. The lagoon a study in imagery The lagoon a study in imagery

    Directory of Open Access Journals (Sweden)

    Carmen Gago Alvarez

    2008-04-01

    Full Text Available The purpose of this paper is to prove that, through exuberant sensuous imagery - the strange tropical setting, the mystery of elements, light and darkness - Joseph Conrad, in his short-story "The Lagoon" describes and transmits Impressionistically, the dramatic story of a men surprised by his own act of cowardice, a man divided between loyalty to his own blood and love. This man, Arsat suffers a blockaded feeling towards himself because he failed to act when he had the occasion, and he missed it: he left his brother to die in the hands of the enemy while he. Arsat, escaped with his love Diamelen, to live in the "shadows" of "The Lagoon" - his own psychological, subconscious guilty conscience. The story starts with a description of nature, as motionless, and undefined as the plot still is: The forests, somber and dull, stood motionless and silent... In the stillness of the air ... minute blossoms seemed do have been bewitched into an immobility perfect and final. Nothing moved on the river (1 The purpose of this paper is to prove that, through exuberant sensuous imagery - the strange tropical setting, the mystery of elements, light and darkness - Joseph Conrad, in his short-story "The Lagoon" describes and transmits Impressionistically, the dramatic story of a men surprised by his own act of cowardice, a man divided between loyalty to his own blood and love. This man, Arsat suffers a blockaded feeling towards himself because he failed to act when he had the occasion, and he missed it: he left his brother to die in the hands of the enemy while he. Arsat, escaped with his love Diamelen, to live in the "shadows" of "The Lagoon" - his own psychological, subconscious guilty conscience. The story starts with a description of nature, as motionless, and undefined as the plot still is: The forests, somber and dull, stood motionless and silent... In the stillness of the air ... minute blossoms seemed do have been bewitched into an

  2. Epidemiology and care of epilepsy in Vietnam

    OpenAIRE

    Tuan, Nguyen Anh

    2010-01-01

    Epilepsy is often considered the most common serious chronic neurological disorder estimated to affect 50 million people globally. Although the majority of these live in developing countries, data on the epidemiology of epilepsy from such countries are scarce. This is true also for Vietnam. The overall objective of this project, Epidemiology and Care of Epilepsy in Ba Vi (EPIBAVI), was therefore to provide essential epidemiological data on epilepsy in Vietnam as a basis for ...

  3. Vietnam Land Policy - Adjusting to Globalization

    Science.gov (United States)

    2013-11-01

    Conflicts over Land in Vietnam’s Red River Delta," Journal of Southeast Asian Studies, (2007): 317, accessed 6 September 2013, JSTOR . 5...Responsibility and No Rice,”: The Rise and Fall of Agricultural Collectivization in Vietnam,” Agricultural History: vol 82, no. 1, (2008), 54, JSTOR . 18...Performance and Communist Legitimacy,” World Politics, vol. 38 no. 3, (1986): 463, accessed 22 October 2013, JSTOR . 32 Ibid., 463. 33 Elliott

  4. Biogeochemical cycling and phyto- and bacterioplankton communities in a large and shallow tropical lagoon (Términos Lagoon, Mexico) under 2009-2010 El Niño Modoki drought conditions

    Science.gov (United States)

    Conan, Pascal; Pujo-Pay, Mireille; Agab, Marina; Calva-Benítez, Laura; Chifflet, Sandrine; Douillet, Pascal; Dussud, Claire; Fichez, Renaud; Grenz, Christian; Gutierrez Mendieta, Francisco; Origel-Moreno, Montserrat; Rodríguez-Blanco, Arturo; Sauret, Caroline; Severin, Tatiana; Tedetti, Marc; Torres Alvarado, Rocío; Ghiglione, Jean-François

    2017-03-01

    The 2009-2010 period was marked by an episode of intense drought known as the El Niño Modoki event. Sampling of the Términos Lagoon (Mexico) was carried out in November 2009 in order to understand the influence of these particular environmental conditions on organic matter fluxes within the lagoon's pelagic ecosystem and, more specifically, on the relationship between phyto- and bacterioplankton communities. The measurements presented here concern biogeochemical parameters (nutrients, dissolved and particulate organic matter [POM], and dissolved polycyclic aromatic hydrocarbons [PAHs]), phytoplankton (biomass and photosynthesis), and bacteria (diversity and abundance, including PAH degradation bacteria and ectoenzymatic activities). During the studied period, the water column of the Términos Lagoon functioned globally as a sink and, more precisely, as a nitrogen assimilator. This was due to the high production of particulate and dissolved organic matter (DOM), even though exportation of autochthonous matter to the Gulf of Mexico was weak. We found that bottom-up control accounted for a large portion of the variability of phytoplankton productivity. Nitrogen and phosphorus stoichiometry mostly accounted for the heterogeneity in phytoplankton and free-living prokaryote distribution in the lagoon. In the eastern part, we found a clear decoupling between areas enriched in dissolved inorganic nitrogen near the Puerto Real coastal inlet and areas enriched in phosphate (PO4) near the Candelaria estuary. Such a decoupling limited the potential for primary production, resulting in an accumulation of dissolved organic carbon and nitrogen (DOC and DON, respectively) near the river mouths. In the western part of the lagoon, maximal phytoplankton development resulted from bacterial activity transforming particulate organic phosphorus (PP) and dissolved organic phosphorus (DOP) to available PO4 and the coupling between Palizada River inputs of nitrate (NO3) and PP. The

  5. Central Facilities Area Sewage Lagoon Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Mark R. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-12-01

    The Central Facilities Area (CFA), located in Butte County, Idaho, at the Idaho National Laboratory has an existing wastewater system to collect and treat sanitary wastewater and non-contact cooling water from the facility. The existing treatment facility consists of three cells: Cell #1 has a surface area of 1.7 acres, Cell #2 has a surface area of 10.3 acres, and Cell #3 has a surface area of 0.5 acres. If flows exceed the evaporative capacity of the cells, wastewater is discharged to a 73.5-acre land application site that uses a center-pivot irrigation sprinkler system. As flows at CFA have decreased in recent years, the amount of wastewater discharged to the land application site has decreased from 13.64 million gallons in 2004 to no discharge in 2012 and 2013. In addition to the decreasing need for land application, approximately 7.7 MG of supplemental water was added to the system in 2013 to maintain a water level and prevent the clay soil liners in the cells from drying out and “cracking.” The Idaho National Laboratory is concerned that the sewage lagoons and land application site may be oversized for current and future flows. A further concern is the sustainability of the large volumes of supplemental water that are added to the system according to current operational practices. Therefore, this study was initiated to evaluate the system capacity, operational practices, and potential improvement alternatives, as warranted.

  6. Paragonimus and paragonimiasis in Vietnam: an update.

    Science.gov (United States)

    Doanh, Pham Ngoc; Horii, Yoichiro; Nawa, Yukifumi

    2013-12-01

    Paragonimiasis is a food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Vietnam, research on Paragonimus and paragonimiasis has been conducted in northern and central regions of the country. Using a combination of morphological and molecular methods, 7 Paragonimus species, namely P. heterotremus, P. westermani, P. skrjabini, P. vietnamensis, P. proliferus, P. bangkokenis and P. harinasutai, have been identified in Vietnam. Of these, the first 3, P. heterotremus, P. westermani and P. skrjabini, are known to infect humans in other countries. However, in Vietnam, only P. heterotremus, found in some northern provinces, has been shown to infect humans. Even nowadays, local people in some northern provinces, such as Lai Chau and Yen Bai, are still suffering from P. heterotremus infection. In some provinces of central Vietnam, the prevalence and infection intensity of P. westermani metacercariae in freshwater crabs (the second intermediate hosts) are extremely high, but human cases have not been reported. Likewise, although P. skrjabini was found in Thanh Hoa Province, its pathogenicity to humans in Vietnam still remains uncertain. The results of molecular phylogenetic analyses of Vietnamese Paragonimus species provides new insights on the phylogeny and taxonomy of the genus Paragonimus. Comprehensive molecular epidemiological and geobiological studies on the genus in Vietnam and adjacent countries are needed to clarify the biodiversity and public health significance of the lung flukes.

  7. Beach Ridge and Lagoon Systems as Indicator of Sea-Level Changes

    DEFF Research Database (Denmark)

    Sander, Lasse

    amounts of unconsolidated sedi-ments for the formation of coastal landforms. Our data show that fine-grained marine sedi-mentation commenced synchronously in near-coastal basins in different elevations which is interpreted as an indication of a period of rapid RSL rise between 7.5 – 7.3 kyr BP. Absolute...... ages established on the marine deposits of the lagoon environments are evidence that condi-tions of marine sedimentation prevailed until at least 4 kyr BP; direct RSL indications for that period are however poorly constrained. A succession of beach ridges within a wide strandplain on Samsø was dated...... to between 4.8 kyr BP and present. The elevations of downlapping reflec-tions in the prograded beach-ridge system are used as a continuous record of RSL develop-ment since the mid-Holocene. Our data indicates a relatively stable RSL at approximately 2.2 m above mean sea-level (MSL) between 4.8 – 3.5 kyr BP...

  8. Mechanism of nitrogen removal in wastewater lagoon: a case study.

    Science.gov (United States)

    Vendramelli, Richard A; Vijay, Saloni; Yuan, Qiuyan

    2017-06-01

    Ammonia being a nutrient facilitates the growth of algae in wastewater and causes eutrophication. Nitrate poses health risk if it is present in drinking water. Hence, nitrogen removal from wastewater is required. Lagoon wastewater treatment systems have become common in Canada these days. The study was conducted to understand the nitrogen removal mechanisms from the existing wastewater treatment lagoon system in the town of Lorette, Manitoba. The lagoon system consists of two primary aerated cells and two secondary unaerated cells. Surface samples were collected periodically from lagoon cells and analysed from 5 May 2015 to 9 November 2015. The windward and leeward sides of the ponds were sampled and the results were averaged. It was found that the free ammonia volatilization to the atmosphere is responsible for most of the ammonia removal. Ammonia and nitrate assimilation into biomass and biological growth in the cells appears to be the other mechanisms of nitrogen removal over the monitoring period. Factors affecting the nitrogen removal efficiency were found to be pH, temperature and hydraulic residence time. Also, the ammonia concentration in the effluent from the wastewater treatment lagoon was compared with the regulatory standard.

  9. The Great Astrolabe Reef lagoon (Fiji) : results of the french-fijian ASTRO expedition

    OpenAIRE

    Charpy, Loïc (ed.); Charpy Roubaud, Claude (ed.); Newell, P. (ed.)

    1996-01-01

    Cet ouvrage comprend les contributions suivantes. p. 1 : phytoplankton biomass and productivity in the Great Astrolabe Lagoon. p. 5 : nutrients and particulate organic matter in The Great Astrolabe Reef Lagoon. p. 11 : sediment constituents in the Great Astrolabe Reef lagoon (Fiji). p. 17 : soft substrate macrobenthos of Fiji's Great Astrolabe Reef lagoon : list of taxons, densities and their biomass. p. 47 : composition et diversité de la méiofaune du lagon de "Great Astrolabe Reef" (Fiji). ...

  10. Teacher Development: A Real Need for English Departments in Vietnam.

    Science.gov (United States)

    Hiep, Pham Hoa

    2001-01-01

    Examines English-as-a-Foreign-Language (EFL) teacher training and teacher development in Vietnam. Suggests ways to promote professional development among EFL teachers in Vietnam, which may be applicable to similar situations in other countries. (Author/VWL)

  11. Sun-Earth System Interaction studies over Vietnam: an international cooperative project

    Directory of Open Access Journals (Sweden)

    C. Amory-Mazaudier

    2006-12-01

    of 400 km in the Vietnamese longitude sector. In this paper we compare the ground magnetic observations of the Indian and Vietnamese magnetometer networks. This comparison highlights the regional structure of the amplitude of the equatorial electrojet, which is stronger in Vietnam than in India. Concerning the monsoon: Vietnam exhibits a strong monsoon and has mainly one rainy season peaking in August, hence associated with the southwest monsoon flow. But some monsoon variability from one place to another is related to the orography. In the mountainous northern regions of Vietnam, there is an "early" monsoon peaking in July. In the coastal regions between 12° N and 19° N the monsoon season is centered on October. Concerning lightning: Vietnam is a country of strong atmospheric storms with some areas of very intense lightning in North Vietnam (22,5° N, 105° E and in South Vietnam (11° N, 107° E. In North Vietnam strong lightning is associated with the most intense rainy region.

  12. Sun-Earth System Interaction studies over Vietnam: an international cooperative project

    Directory of Open Access Journals (Sweden)

    C. Amory-Mazaudier

    2006-12-01

    CHAMP satellite at the height of 400 km in the Vietnamese longitude sector. In this paper we compare the ground magnetic observations of the Indian and Vietnamese magnetometer networks. This comparison highlights the regional structure of the amplitude of the equatorial electrojet, which is stronger in Vietnam than in India.

    Concerning the monsoon: Vietnam exhibits a strong monsoon and has mainly one rainy season peaking in August, hence associated with the southwest monsoon flow. But some monsoon variability from one place to another is related to the orography. In the mountainous northern regions of Vietnam, there is an "early" monsoon peaking in July. In the coastal regions between 12° N and 19° N the monsoon season is centered on October.

    Concerning lightning: Vietnam is a country of strong atmospheric storms with some areas of very intense lightning in North Vietnam (22,5° N, 105° E and in South Vietnam (11° N, 107° E. In North Vietnam strong lightning is associated with the most intense rainy region.

  13. Comparison between different methodologies of environmental sensitivity classification for lagoons; Comparacao entre diferentes metodologias de classificacao do indice de sensibilidade do litoral a derramamentos de oleo para ambientes lagunares

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Carine; Cabral, Alexandre; Griep, Gilberto Henrique [Fundacao Universidade do Rio Grande (FURG), Rio Grande, RS (Brazil)

    2008-07-01

    This paper aims to show a brief presentation about the variation of Environmental Sensibility Index (ISL) to west coast of Patos Lagoon, in Rio Grande do Sul State, Brazil, between the seasons winter and summer. Furthermore, it compares two different methodologies for Sensibility Classification: the first one, for fluvial environments, which was suggested by PETROBRAS, 2006 and other one for either coastal and tidal environments, suggested by Environmental Ministry, 2002. (author)

  14. Ocean-lagoon water and plankton exchanges in a semi-closed pearl farming atoll lagoon (Ahe, Tuamotu archipelago, French Polynesia)

    Science.gov (United States)

    Pagano, M.; Rodier, M.; Guillaumot, C.; Thomas, Y.; Henry, K.; Andréfouët, S.

    2017-05-01

    In atoll lagoons, plankton richness is highly dependent on water exchange with the ocean through the atoll rim. However, the dynamics of the physical and biological fluxes at the lagoon-ocean interface remain poorly characterized. Here, we studied the combined effects of lagoon-ocean water exchanges and local environmental conditions on the phyto- and zooplankton abundance and community structure across the atoll lagoon rim of Ahe (Tuamotu Archipelago, French Polynesia). Plankton and environmental variables were monitored in May 2013 (i) at several stations inside and outside the lagoon and (ii) during time-series corresponding to ebb-flood tidal cycles in the two types of channels connecting the lagoon to the ocean: at the passage (300 m long and about 11 m deep) and in hoa (i.e reef-flat less than 50 cm depth). Our results highlight tidally-driven selective plankton exchanges between the lagoon and external ocean. Phytoplankton (chlorophyll-a) and zooplankton biomass were respectively 4 times and 7 times higher in the lagoon than at stations outside the atoll lagoon. Copepoda was the dominant zooplankton group at the oceanic station (>75% abundance) whereas meroplankton (with bivalve larvae most common) was dominant at the lagoon stations (54%), in the passage (55-82%) and in hoa (>80%). These differences between sites suggest a loss of bivalve larvae through export to the ocean and retention and/or increased production of copepods in the lagoon. The daily export of bivalve larvae represents a low percentage of the lagoon stock, in agreement with previously published larval dispersal numerical models. The retention of copepods could constitute a significant input of nutrients and organic matter (through excretion, feces release, decomposition, and remineralization) into the lagoon.

  15. On the Hydrodynamic Geometry of Flow-Through versus Restricted Lagoons

    Directory of Open Access Journals (Sweden)

    Nikolaos Th. Fourniotis

    2018-02-01

    Full Text Available The classification of a lagoon as a restricted lagoon is shown to depend not solely on its geometry but also on the tidal hydraulics. By numerically simulating the tidal exchange of two lagoons of similar geometrical dimensions, the Nidova lagoon and the Papas lagoon, in Western Greece, subject to very similar tidal forcing, applied to the two tidal inlets in the first case and three in the second, very different residence times are found, namely 2.5 days for the Nidova and 25–30 days for the Papas lagoon. This large difference is attributed to the fact that whereas the Papas lagoon functions as a typical restricted lagoon, in which the water renewal is achieved by mixing in the lagoon of the tidal prism water exchanged within a tidal cycle, the Nidova lagoon functions as a flow-through system because of the differential arrival of the tide at its two tidal inlets. It is suggested that this way of enhancing the flushing rate of a lagoon be considered, whenever possible, when creating a new tidal inlet to the lagoon.

  16. Phytoplankton dynamics in relation to environmental changes in a phytoplankton-dominated Mediterranean lagoon (Cabras Lagoon, Italy

    Directory of Open Access Journals (Sweden)

    B.M. Padedda

    2012-09-01

    Full Text Available In Mediterranean lagoons, macrophytes often surpass phytoplankton as the most important primary producers. Less frequently, phytoplankton dominates throughout the year, thus knowledge of its dynamics is relatively limited and scattered. In this study, we assessed over two years the dynamics of phytoplankton assemblages, including potential harmful algal species (HAS, in relation to environmental changes in the phytoplankton-dominated Cabras Lagoon (Sardinia, Italy. The lagoon was characterised by uniform spatial conditions, wide temporal variations in salinity (40 PSU and high nutrient availability. Phosphorus was highest in summer, possibly recycled within the system, while dissolved inorganic nitrogen increased in winter and spring due to watershed discharge. Chlorophyll a, positively correlated with nutrients and rainfall, showed a typical bimodal pattern with summer-winter blooms. Modifications in phytoplankton composition strongly correlated with extreme weather events, such as intense rainfall. This generated an abrupt salinity decrease that, combined with high nutrient availability, favoured the dominance of Cyanophyceae of reduced cell size, such as Cyanobium and Rhabdoderma species. We suggest that the prolonged and intense dominance of Cyanophyceae, added to other HAS, has a negative impact on the primary economic activities of the lagoon, such as fishery, and generally on the whole lagoon functioning.

  17. Psychological operations supporting counterinsurgency: 4th Psyop Group in Vietnam.

    Science.gov (United States)

    2007-06-15

    Vietnam COSVN Central Office for South Vietnam CTZ Corps Tactical Zone DMZ Demilitarized Zone DRV Democratic Republic of Vietnam (North Vietnam...agencies in each CTZ due to lack of coordination and centralized control.”29 While these examples do not indicate widespread or egregious issues...commands equivalent to a Corps at the time of the ACTIV survey, III Marine Amphibious Force (MAF) in First Corps Tactical Zone (I CTZ ), First Field

  18. Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    1999-09-01

    As a Party to the United Nations Framework Convention on Climate Change (UNFCCC) Viet Nam will make its strong effort to implement the UNFCCC through effective activities in order to reduce GHG emissions as well as enhance carbon sinks in the country. The UNEP/GEF Project `Economics of GHG Limitation - Phase 1: Establishment of a Methodological Framework for Climate Change Mitigation Assessment` developed by the UNEP Collaborating Centre on Energy and Environment (UCCEE) in cooperation with Lawrence Berkeley Laboratory has been deployed in Viet Nam since 1996. The project deals with GHG mitigation analysis and options, focusing on the main issues: a) Associated macro-economics, b) Energy, c) Land use and forestry. For this study, a number of different data related to energy, industry, forestry and agriculture sectors as well as Viet Nam socio-economic development up to the year 2030, are collected. Besides, several models such as MEDEE-S, EFOM-ENV, COMAP are applied for development and assessment of GHG mitigation options in the next decades. The MEDEE-S and EFOM-ENV models are used as a tool for determining the cost-effective strategies to abate GHG emissions for energy sector while COMAP model is applied for forestry sector. (au) 39 refs.

  19. Women at war: The crucible of Vietnam.

    Science.gov (United States)

    Pless Kaiser, Anica; Kabat, Daniel H; Spiro, Avron; Davison, Eve H; Stellman, Jeanne Mager

    2017-12-01

    Relatively little has been written about the military women who served in Vietnam, and there is virtually no literature on deployed civilian women (non-military). We examined the experiences of 1285 American women, military and civilian, who served in Vietnam during the war and responded to a mail survey conducted approximately 25 years later in which they were asked to report and reflect upon their experiences and social and health histories. We compare civilian women, primarily American Red Cross workers, to military women stratified by length of service, describe their demographic characteristics and warzone experiences (including working conditions, exposure to casualties and sexual harassment), and their homecoming following Vietnam. We assess current health and well-being and also compare the sample to age- and temporally-comparable women in the General Social Survey (GSS), with which our survey shared some measures. Short-term (Vietnam experience as "highly stressful" than were career (>20 years; 12%) and civilian women (13%). Additional differences regarding warzone experiences, homecoming support, and health outcomes were found among groups. All military and civilian women who served in Vietnam were less likely to have married or have had children than women from the general population, χ 2 (8) = 643.72, p Vietnam reported better health than women in the other groups. Regression analyses indicated that long-term physical health was mainly influenced by demographic characteristics, and that mental health and PTSD symptoms were influenced by warzone and homecoming experiences. Overall, this paper provides insight into the experiences of the understudied women who served in Vietnam, and sheds light on subgroup differences within the sample.

  20. State Waste Discharge Permit application, 100-N Sewage Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations (Ecology et al. 1994), the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173--216 (or 173--218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order No. DE 91NM-177, (Ecology and DOE-RL 1991). This document constitutes the State Waste Discharge Permit application for the 100-N Sewage Lagoon. Since the influent to the sewer lagoon is domestic waste water, the State Waste Discharge Permit application for Public Owned Treatment Works Discharges to Land was used. Although the 100-N Sewage Lagoon is not a Public Owned Treatment Works, the Public Owned Treatment Works application is more applicable than the application for industrial waste water. The 100-N Sewage Lagoon serves the 100-N Area and other Hanford Site areas by receiving domestic waste from two sources. A network of sanitary sewer piping and lift stations transfers domestic waste water from the 100-N Area buildings directly to the 100-N Sewage Lagoon. Waste is also received by trucks that transport domestic waste pumped from on site septic tanks and holding tanks. Three ponds comprise the 100-N Sewage Lagoon treatment system. These include a lined aeration pond and stabilization pond, as well as an unlined infiltration pond. Both piped-in and trucked-in domestic waste is discharged directly into the aeration pond.

  1. Spatial patterns of diversity at local and regional scales in a tropical lagoon

    Directory of Open Access Journals (Sweden)

    José Adán Caballero-Vázquez

    Full Text Available The present study reports estimates of alpha (α, beta (β and gamma (Γ diversity for the fish community of Chacmochuch Lagoon (SE Mexico, a natural protected area located in the northern portion of the Mesoamerican Barrier Reef System. Fish specimens were sampled in 2004 and 2006. Field work was carried out at three climatic peaks: at 13 stations using a 70 m-long beach seine. The collected data were supplemented with information obtained from a previous work conducted in 2002 and were then analyzed with multivariate statistical methods. In addition, fish composition results from this study were compared to those reported for other similar ecosystems of the region. A total of 68 fish species were recorded, determined as peripheral (high-salinity species, usually marine affinity most of them. Most of the fish species collected were determined as rare, and a few number of species were determined as common and dominant. Salinity, TSD, temperature, dissolved oxygen and other variables were measured to determine the influence over the fish communities, four groups of sites where determined. Results indicated a gradual decrease in the degree of species replacement towards the interior of the system (away from the coast. The estimated value of gamma diversity was high compared to that reported for other coastal systems of the region and, due to the high degree of habitat heterogeneity found in this system; beta diversity had a greater contribution to gamma diversity than alpha diversity. This lagoon acts as a nursing area for many of the fish species collected in this study as indicated by the presence of juvenile stages.

  2. Spatial and temporal variation in fish community of the Ria de Aveiro estuarine lagoon (Portugal.

    Directory of Open Access Journals (Sweden)

    Eva García-Seoane

    2015-11-01

    Full Text Available Fish assemblages of Ria de Aveiro coastal lagoon (Northwest Portugal were studied from February 2012 and January 2013. Sampling were monthly conducted with a traditional beach-seine net (“chincha” at 9 sites. Multivariate approach were used in order to analyse the spatial and temporal variation in fish community. A total of 58,201 fishes, weighting 249,540 g, were identified, representing 37 taxa and 21 families. Four taxa (Atherina spp., Dicentrarchus labrax, Liza spp., and Sardina pilchardus were responsible for 94.7% and 85.4% of the total abundance, in number and weight. There were significant differences in fish community, in terms of fish number and weight, between sites and between months (ANOSIM, p<0.01. A total of 12 species appeared as characteristics of one of more sampling sites either in terms of number and weight. In both cases, D. labrax, Liza spp. and Atherina spp. were typical throughout the study area. Other species, such as Spondyliosoma cantharus appeared as typical only in the part of the lagoon more influenced by marine waters, whereas Anguilla anguilla was typical of the inner area. A total of 11 (in number or 13 (in weight species appeared as typical of at least one month of the year. Liza spp. and Atherina spp. were typical all the year round for number and weight data. In both cases, D. labrax, Diplodus spp. and S. pilchardus, appeared as a typical from spring to autumn. The number of typical species varied with the season, being maximum in May and minimum in winter. Finally, results of this work were discussed in comparison to previous studies.

  3. [Spatial and temporal mangrove litter production in Barra de Navidad lagoon, Jalisco, México].

    Science.gov (United States)

    Mendoza-Morales, Alma J; González-Sansón, Gaspar; Aguilar-Betancourt, Consuelo

    2016-03-01

    Barra de Navidad lagoon is a coastal wetland of international importance (Ramsar site) and it is included among the 81 Mexican mangrove priority sites. One of the most valued characteristics of this lagoon is the presence of mangrove forest in a good conservation state. The goal of our research was the measurement of mangrove litter production and environmental factors influencing its dynamics. The mangrove area was divided into seven zones and litterfall was monthly sampled from November 2011 to October 2012 using 0.25 m(2) square collectors made with mosquito mesh (1 mm) and positioned at 1.3 m above the ground. Abiotic variables of the interstitial water were measured simultaneously at each zone in permanent plots using a multi-parameter probe, YSI-556-M. Total mean value of litterfall production, weighted by zone surface, was 19.12 ± 1.23 gPS/m(2).mo (2.29 t/ha.year). This low productivity is a consequence of the region’s dry climate and low tide range. The species Avicennia germinans and Laguncularia racemosa produced more than 80 % of total litterfall, while Rhizophora mangle contributed only 16 % and Conocarpus erectus < 4 %. A significant correlation between litterfall production and abiotic variables was found (e.g. salinity and interstitial water depth). We concluded that there are significant spatial variations in soil abiotic variables which are correlated with differences in mangrove species composition, and produce, together with the life cycles stages of those species, significant variations in the quantity and composition of litterfall. Future research will be focused on quantifying spatial variations in forest structure and their relationship with litterfall production.

  4. The Determinants and Impact of Private Tutoring Classes in Vietnam

    Science.gov (United States)

    Dang, Hai-Anh

    2007-01-01

    Private tutoring is a widespread phenomenon in many developing countries, including Vietnam. Using the Vietnam Living Standards Surveys 1997-1998 and 1992-1993 for analysis, this paper finds evidence that private tutoring in Vietnam is a necessity in the household budget for both primary students and lower secondary students, and the trend to…

  5. 78 FR 7452 - Steel Wire Garment Hangers From Vietnam; Determinations

    Science.gov (United States)

    2013-02-01

    ... COMMISSION Steel Wire Garment Hangers From Vietnam; Determinations On the basis of the record \\1\\ developed... imports of steel wire garment hangers from Vietnam, provided for in subheading 7326.20.00 of the... countervailing and antidumping duty orders on steel wire garment hangers from Vietnam. Background The Commission...

  6. Current status of soil-transmitted helminths in Vietnam

    DEFF Research Database (Denmark)

    van der Hoek, Wim; De, Nguyen Van; Konradsen, Flemming

    2003-01-01

    This paper provides a review of surveys on soil-transmitted helminths that were done in Vietnam between 1990 and 2001. Prevalence estimates could be obtained for 29 of the 61 provinces. Extrapolating from this, it is estimated that 33.9 million people in Vietnam are infected with Ascaris......, and human behavioral factors in the transmission of intestinal nematode infections in Vietnam....

  7. 45 CFR 506.10 - “Vietnam conflict” defined.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false âVietnam conflictâ defined. 506.10 Section 506.10... OF THE WAR CLAIMS ACT OF 1948, AS AMENDED ELIGIBILITY REQUIREMENTS FOR COMPENSATION Prisoners of War § 506.10 “Vietnam conflict” defined. Vietnam conflict refers to the period beginning February 28, 1961...

  8. Diversity of Vibrio spp in Karstic Coastal Marshes in the Yucatan Peninsula.

    Science.gov (United States)

    Ortiz-Carrillo, Icela; Estrella-Gómez, Neyi Eloísa; Zamudio-Maya, Marcela; Rojas-Herrera, Rafael

    2015-01-01

    Coastal bodies of water formed by the combination of seawater, underground rivers and rainwater comprise the systems with the greatest solar energy flow and biomass production on the planet. These characteristics make them reservoirs for a large number species, mainly microorganisms. Bacteria of the genus Vibrio are natural inhabitants of these environments and their presence is determined by variations in the nutrient, temperature and salinity cycles generated by the seasonal hydrologic behavior of these lagoon systems. This study determined the diversity of the genus Vibrio in 4 coastal bodies of water on the Yucatan Peninsula (Celestun Lagoon, Chelem Lagoon, Rosada Lagoon and Sabancuy Estuary). Using the molecular technique of 454 pyrosequencing, DNA extracted from water samples was analyzed and 32,807 reads were obtained belonging to over 20 culturable species of the genus Vibrio and related genera. OTU (operational taxonomic unit) richness and Chao2 and Shannon Weaver diversity indices were obtained with the database from this technique. Physicochemical and environmental parameters were determined and correlated with Vibrio diversity measured in OTUs.

  9. Diversity of Vibrio spp in Karstic Coastal Marshes in the Yucatan Peninsula

    Science.gov (United States)

    2015-01-01

    Coastal bodies of water formed by the combination of seawater, underground rivers and rainwater comprise the systems with the greatest solar energy flow and biomass production on the planet. These characteristics make them reservoirs for a large number species, mainly microorganisms. Bacteria of the genus Vibrio are natural inhabitants of these environments and their presence is determined by variations in the nutrient, temperature and salinity cycles generated by the seasonal hydrologic behavior of these lagoon systems. This study determined the diversity of the genus Vibrio in 4 coastal bodies of water on the Yucatan Peninsula (Celestun Lagoon, Chelem Lagoon, Rosada Lagoon and Sabancuy Estuary). Using the molecular technique of 454 pyrosequencing, DNA extracted from water samples was analyzed and 32,807 reads were obtained belonging to over 20 culturable species of the genus Vibrio and related genera. OTU (operational taxonomic unit) richness and Chao2 and Shannon Weaver diversity indices were obtained with the database from this technique. Physicochemical and environmental parameters were determined and correlated with Vibrio diversity measured in OTUs. PMID:26252792

  10. Antibiotic contaminants in coastal wetlands from Vietnamese shrimp farming.

    Science.gov (United States)

    Thuy, Hoang Thi Thanh; Nga, Le Phi; Loan, Tu Thi Cam

    2011-07-01

    Shrimp culture has been expanded rapidly in recent years in coastal wetland zone of Vietnam due to favorable natural conditions. However, this industry has caused several negative impacts to the environment. One of the critical issues is the excessive application of antibiotics including human medicines. These chemicals could be released from shrimp ponds and then accumulated and contaminated of the ecosystem. This review article discusses a whole range of findings that address various aspects of the usage, occurrence and potentially environmental risks of antibiotics released from shrimp farming, with emphasis on the South Vietnam coastal wetland. The published information on the usage and occurrence of antibiotics in Vietnamese shrimp farming has been reviewed. A global comparison was also carried out. This follows by a brief overview of the transport and fate of these antibiotics in the environment. Several antibiotics commonly used in Vietnamese shrimp culture have been detected in wastewater and sediment of the ponds, as well as in surrounding coastal wetlands, resulting in the existence of antibiotic-resistant bacteria. However, their transport and fate could not be clearly defined. The well-documented accumulation of antibiotics in mud and sediments in Vietnamese coastal wetlands potentially poses serious risks for the local wetland ecosystems. Thus, research on the transport and fate of antibiotics' residues from the ponds into the surrounding environment is urgently needed.

  11. Shallow gas accumulation in sediments of the Patos Lagoon, southern Brazil

    Directory of Open Access Journals (Sweden)

    Jair Weschenfelder

    2006-09-01

    Full Text Available A high resolution seismic survey was conducted in the Patos Lagoon, southern Brazil, aboard of the research vessel LARUS of the Fundação Universidade Federal do Rio Grande (FURG. Around 400 km of 3.5 kHz seismic profiles were collected, which provided acoustic signals of good penetration depth and resolution. Seismic anomalies, including turbidity and pocket gas, revealed that gas-charged sediments are common in several areas of the lagoon. The gas accumulations in the Patos Lagoon are controlled by the spatial distribution of the sedimentary facies. Either in 'curtains' or in 'acoustic turbid zones', the main gas accumulations occur in areas with paleotopographic lows related to fluvial channels and valleys developed in the Rio Grande do Sul coastal plain during regressive/transgressive events of the Quaternary.Um levantamento sísmico de alta resolução foi realizado na Lagoa dos Patos, sul do Brasil, a bordo da Lancha Oceanográfica Larus da Fundação Universidade Federal do Rio Grande (FURG. Foram levantados aproximadamente 400 km de perfis de 3,5 kHz, os quais apresentaram uma resposta acústica de boa penetração e resolução. Anomalias sísmicas, incluindo turbidez acústica e bolsões de gás, revelam que sedimentos carregados de gás são comuns em diversas áreas do corpo lagunar. As acumulações de gás na Lagoa dos Patos são controladas pela distribuição espacial das fácies sedimentares. Tanto as acumulações de gás na forma de 'cortinas', como as 'zonas acusticamente turvas', ocorrem em área de baixios paleotopográficos, vinculados a vales e canais fluviais que se desenvolveram na planície costeira do Rio Grande do Sul durante os eventos regressivos/transgressivos do Quaternário.

  12. Atmospheric concentrations, occurrence and deposition of persistent organic pollutants (POPs) in a Mediterranean coastal site (Etang de Thau, France)

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Jimenez, J., E-mail: javier.castro-jimenez@idaea.csic.es [European Commission-Joint Research Centre, Institute for Environment and Sustainability, via E. Fermi 2749, 21027 Ispra (Italy); Mariani, G.; Vives, I.; Skejo, H.; Umlauf, G. [European Commission-Joint Research Centre, Institute for Environment and Sustainability, via E. Fermi 2749, 21027 Ispra (Italy); Zaldivar, J.M. [European Commission-Joint Research Centre, Institute for Health and Consumer Protection, via E. Fermi 2749, 21027 Ispra (Italy); Dueri, S. [CRH, UMR 212 EME, Institut de Recherche pour le Developpement, Avenue Jean Monnet BP 171, 34203 Sete Cedex (France); Messiaen, G.; Laugier, T. [Ifremer, Environment and Resources Laboratory, Avenue Jean Monnet BP 171, 34203 Sete Cedex (France)

    2011-07-15

    Atmospheric concentrations and deposition fluxes of PCDD/F and PCB have been evaluated over a 1-year period in a Mediterranean coastal lagoon (Etang de Thau, France). Indicative PBDE air concentrations in the hot season are also reported in this work. {Sigma}2,3,7,8-PCDD/Fs and {Sigma}18PCBs (gas + particulate) air concentrations ranged from 67 to 1700 fg m{sup -3} and from 13 to 95 pg m{sup -3}, respectively whereas {Sigma}8PBDEs (gas + particulate) summer time levels varied from 158 to 230 pg m{sup -3}. The PCDD/F and PCB atmospheric occurrence over Thau lagoon and subsequent inputs to the surface waters are determined by an assemble of factors, being the seasonality of atmospheric concentration, the air mass origin and meteorological conditions important drivers. Total (wet + dry) {Sigma}2,3,7,8-PCDD/Fs and {Sigma}18PCBs deposition fluxes to Thau Lagoon waters are 117 and 715 pg m{sup -2} d{sup -1}, respectively. - Highlights: > PCDD/F and PCB atmospheric concentrations in Thau lagoon are typical from rural/semi-rural areas. > PBDE atmospheric concentrations in Thau lagoon are typical from urban/industrial sites. > PCDD/F and PCB atmospheric concentrations over Thau lagoon and inputs to surface waters are very variable, even changing between the same week of the month in two consecutive years. > Metallurgical industry may be a possible local source of PCDD/Fs in the Thau lagoon basin. > Annual PCBs and PCDD/Fs atmospheric inputs are dominated by dry deposition - PCDD/F and PCB atmospheric concentrations over Thau lagoon and inputs to surface waters are very variable, even changing between the same week of the month in two consecutive years.

  13. Population studies on the Amphipoda of Mazoma Lagoon (Greece)

    Science.gov (United States)

    Karakiri, Maria; Nicolaidou, Artemis

    1987-12-01

    The life cycles of four amphipod species— Gammarus insensibilis, Dexamine spinosa, Microdeutopus gryllotalpa and Corophium insidiosum—were studied in the brackish-water lagoon Mazoma of the Amvrakikos Gulf, Ionian Sea. G. insensibilis has an annual life cycle with limited recruitment over the year and maximum reproductive activity in the winter months. D. spinosa exhibits continuous recruitment in the lagoon with a maximum in summer. Both species produce a single brood per female per yer. Continuous recruitment was observed during the summer months for M. gryllotalpa and C. insidiosum, and multiple breeding per female per year. Sex ratios varied considerably over the year, with a persisting preponderance of the females.

  14. Determination of the grow-out density of Farfantepenaeus paulensis (Perez-Farfante, 1967 shrimp juveniles with a view to providing alternative culture structures (pens in Ibiraquera Lagoon, Imbituba, Santa Catarina

    Directory of Open Access Journals (Sweden)

    Luis Vinatea

    2007-09-01

    Full Text Available Ibiraquera Lagoon, which is located between the municipalities of Garopaba and Imbituba, both in Santa Catarina, a state of southern Brazil, was set up in the last decade as part of a Program for the Restocking of Coastal Lagoons. This program obtained successful results for several years. However, nowadays the productivity of this natural environment has probably been reduced because of its overfishing, specially of the pink shrimp Farfantepenaeus paulensis (Perez-Farfante, 1967, and above all the effect of anthropogenic factors. Such facts have led some researchers to question the viability of successfully restocking the lagoon, since eutrophication would be accelerated by several other factors. Thus, to discover whether the young of F. paulensis could grow and survive feeding only on the natural food of the lagoon´s environment, and whether they were able to tolerate the quality of the water, an experiment was designed to calculate how the lagoon would support future restocking. To this end a farming process was set up which lasted 93 days, testing 3 different densities: 1, 1.5, and 2 shrimps/m2 in standard circular pens of 50 m2. Results after the farming period regarding growth the physico-chemical parameters indicated values in the expected range that fell within the tolerance limits for the survival and satisfactory development of the young of F. paulensis, since significant differences in the daily fluctuations of the dissolved oxygen (OD were not found. Results on the growth were also found to have similar values to those found by other researchers in the dos Patos Lagoon, in the neighboring state of Rio Grande do Sul. Treatment with a density of 1 shrimp/m2 was significantly different (p<0.05 in relation to the other two treatments with densities of 1.5 and 2, both of which had very similar values. However, the final results of shrimp survival and polychaeta biomass throughout the experiment did not present significant differences (p

  15. The black flies (Diptera: Simuliidae) of Vietnam.

    Science.gov (United States)

    Takaoka, Hiroyuki; Sofian-Azirun, Mohd; Ya'cob, Zubaidah; Chen, Chee Dhang; Lau, Koon Weng; Low, VAN Lun; Pham, Xuan DA; Adler, Peter H

    2017-05-05

    The biodiversity of black flies (Diptera: Simuliidae), which are biting insects of medical and veterinary importance, is strikingly high in Southeast Asian countries, such as Indonesia, Malaysia, Philippines and Thailand. In 2013, we began to explore the fauna of black flies in Vietnam, which has so far been poorly studied. In this monograph, the wealth of the biodiversity of black flies in Vietnam is also confirmed on the basis of the results of our recent investigations, though limited to five provinces in the country.      Morphotaxonomic studies of black flies obtained from Sapa, Lao Cai Province, northern Vietnam, in 2014 and Nghe An Province, northern Vietnam, in 2015, and reexaminations of black flies collected from Tam Dao, Vinh Phuc Province, northern Vietnam, in 2013, Thua Thien Hue Province, central Vietnam, in 2014, and Lam Dong Province, southern Vietnam, in 2014, were conducted. A total of 22 species are described as new, including one in the newly recorded subgenus Montisimulium Rubtsov, and three species are recognized as new records from Vietnam. This investigation brings the number of species of black flies known in Vietnam to 70, all of which are assigned to the genus Simulium Latreille, and are placed in four subgenera (25 in Gomphostilbia Enderlein, one in Montisimulium, seven in Nevermannia Enderlein, and 37 in Simulium Latreille s. str.). The numbers of species-groups recognized include seven in Gomphostilbia, three in Nevermannia and nine in Simulium, indicating a high diversity of putative phylogenetic lineages. New species include S. (G.) sanchayense sp. nov. (= the species formerly regarded as S. (G.) brinchangense Takaoka, Sofian-Azirun & Hashim), S. (S.) lowi sp. nov. (= the species formerly regarded as S. (S.) brevipar Takaoka & Davies), S. (S.) fuscicoxae sp. nov. [= the species formerly regarded as S. (S.) rufibasis Brunetti (in part)], S. (S.) suoivangense sp. nov. [= morphoform 'b' of the S. (S.) tani Takaoka & Davies (complex

  16. The Lessons of the Vietnam War: Unit 13. Teacher's Manual: Strategies and Resources for Teaching the Vietnam War.

    Science.gov (United States)

    Center for Social Studies Education, Pittsburgh, PA.

    This teacher's manual is designed to accompany the curriculum "The Lessons of the Vietnam War." For each of 12 units of the curriculum, this manual suggests projects for student research and classroom activities. The 12 units are entitled: (1) Introduction to Vietnam: land, history and culture; (2) America at war in Vietnam: decisions and…

  17. Vietnam military service history and prostate cancer

    Directory of Open Access Journals (Sweden)

    Fritschi Lin

    2006-03-01

    Full Text Available Abstract Background Three decades after US and Australian forces withdrew from Vietnam, there has been much public interest in the health consequences of service in Vietnam. One controversial question is whether the risk of prostate cancer amongst Vietnam veterans is increased. This paper examines relationships between military history, family history and risk of prostate cancer in a population-based case control study. Methods Cases were selected from the Cancer Registry of Western Australia as incident cases of histologically-confirmed prostate cancer, and controls were age-matched and selected from the Western Australian electoral roll. Study participants were asked to report any military service history and details about that service. Results Between January 2001 and September 2002, 606 cases and 471 controls aged between 40–75 years were recruited. An increased prostate cancer risk was observed in men reporting they were deployed in Vietnam although this was not statistically significant (OR = 2.12; 95% CI 0.88–5.06. An increased risk was also observed in men reporting prostate cancer in fathers (OR = 1.90; 95% CI 1.20–3.00 or brothers (OR = 2.05; 95% CI 1.20–3.50 diagnosed with prostate cancer. Conclusion These findings support a positive association between prostate cancer and military service history in the Vietnam war and a first degree relative family history of prostate cancer.

  18. Entry modes of European firms in Vietnam

    Directory of Open Access Journals (Sweden)

    Daniel Simonet

    2012-09-01

    Full Text Available Purpose: The purpose of the paper is to explore the entry modes of EU firms setting up operations in Vietnam. Design/methodology/approach: we use a case study approach on Haymarket, Cadbury, Creative Education, Fairchild, Aventis and Artemisinin and Farming International using interviews from managerial professionals in Vietnam. Findings: Despite the fact that Vietnam has been opening up for more than 20 years, licensing is the preferred entry mode because of the risks involved in venturing with local firms; that preference signals a low level commitment and a high perception of risk and state interference. In line with Vietnam transition to state - rather than private market - capitalism, a foreign company opting for a joint-venture will do so with a state-owned rather than privately-owned company. The choice of a subsidiary can be explained by the lack of trust in partners and institutions, not by improvement in the socio-political environment. Limitations: In determining the entry mode strategy, the paper focuses on the Uppsala school’s “psychic distance” (e.g. cultural distance, lack of trust rather than on firm-specific advantages (Rugman, 1980; 2006. Key-words: international entry mode; emerging markets; subsidiary; joint-venture; India; Vietnam

  19. Review: Results of studying atmospheric corrosion in Vietnam 1995–2005

    Directory of Open Access Journals (Sweden)

    Le Thi Hong Lien, Pham Thy San and Hoang Lam Hong

    2007-01-01

    Full Text Available Vietnam is situated in the wet tropical zone; thus, atmospheric conditions are characterized by high temperatures and a long time of wetness (TOW. In addition, the salt air coming in from the sea causes a high chloride concentration in coastal areas. Furthermore, Vietnam is a developing country, which means that air pollution is increasing with the development of industry. These factors result in significant damage to materials by atmospheric corrosion. In this report, the results of a recent study on the corrosion of carbon steel and zinc-galvanized steel at 6–8 testing sites in Vietnam over 10 recent years (1995–2005 are focused on as well as the effects of environmental factors on atmospheric corrosion. The results showed that the corrosion of carbon steel is dominated by TOW, whereas zinc-galvanized-steel corrosion strongly depends on the chloride ion concentration in the air. The corrosion losses of both carbon- and zinc-galvanized steel fit the power model well with high correlation coefficients. In addition, the characteristics of the Vietnamese climate are introduced in the form of distribution maps of temperature (T, relative humidity (RH, total rainfall and TOW. A relationship between TOW, T and RH was found that enabled the calculation of TOW from T and RH data, which are available at meteorological stations. Finally, atmospheric corrosivity is determined on the basis of data on TOW, Cl− and SO2 concentrations, and the carbon steel corrosion rate. It is shown that in Vietnam, TOW is so long that the corrosion rate of carbon steel is in the C3 category; nevertheless, Cl− and SO2 concentrations in the atmosphere are not high.

  20. Evolution of the Rømø barrier island in the Wadden Sea: Impacts of sea-level change on coastal morphodynamics

    DEFF Research Database (Denmark)

    Clemmensen, Lars B; Andersen, Thorbjørn Joest; Johannessen, Peter

    , and falling sea-level, whereas wash-over sedimentation was promoted during periods of rapid sea-level rise when shoreface, beach and coastal dune deposits were reworked. In contrast, lagoonal sedimentation has been relatively continuous and kept pace with the long-term Holocene sea-level rise. Our findings...

  1. Suicide of Australians during the Vietnam War.

    Science.gov (United States)

    Pridmore, Saxby; Ahmadi, Jamshid; Pridmore, William

    2017-10-01

    National suicide rates fall during times of war. This fits with the notion of the population coming together against a common foe. But, what happens in the case of a war which is not fully supported, which draws the population and families apart? We consider this question by examining the Australian suicide rates during the divisive Vietnam War. We graphed and examined the Australian suicide figures for 1921-2010. We found clear evidence of a decrease in the suicide rate for World War II (consistent with other studies), but a marked elevation of suicide during the Vietnam War. The elevation of the Australian suicide rate during the Vietnam War is consistent with Durkheim's social integration model - when social integration is lessened, either by individual characteristics or societal characteristics, the risk of suicide rises.

  2. Lightning protection for wind turbines in Vietnam

    Directory of Open Access Journals (Sweden)

    Thuan Nguyen

    2017-01-01

    Full Text Available Wind energy has become increasingly important in the total electrical energy supply mix in Vietnam over the last few years. Small, kW turbines were installed in isolated areas a decade ago, while wind farms of several MW to few hundred MW are now being connected directly to national grid, with many additional projects in planning or under construction to fulfill an objective of 6% of the total installed capacity by 2030 (approximately 6200 MW of wind energy component. The increase in wind farm generation results in increased damage from lightning. In this paper, the annual frequency of lightning strikes to wind turbines in Vietnam is calculated using electrogeometric model. Reported lightning incidents to three major wind farms in Vietnam are summarized. Possible causes of failure are discussed, and an EMTP simulation for each incident was performed accordingly. The simulations suggest the failure mechanisms as well the potential of improved grounding to reduce lightning induced damage in future windfarms.

  3. Women at war: The crucible of Vietnam

    Directory of Open Access Journals (Sweden)

    Anica Pless Kaiser

    2017-12-01

    Short-term (20 years; 12% and civilian women (13%. Additional differences regarding warzone experiences, homecoming support, and health outcomes were found among groups. All military and civilian women who served in Vietnam were less likely to have married or have had children than women from the general population, χ2 (8 = 643.72, p < .001. Career military women were happier than women in the general population (48% were “very happy”, as compared to 38%. Civilian women who served in Vietnam reported better health than women in the other groups. Regression analyses indicated that long-term physical health was mainly influenced by demographic characteristics, and that mental health and PTSD symptoms were influenced by warzone and homecoming experiences. Overall, this paper provides insight into the experiences of the understudied women who served in Vietnam, and sheds light on subgroup differences within the sample.

  4. Technique de lombriculture au Sud Vietnam

    Directory of Open Access Journals (Sweden)

    Haubruge E.

    2003-01-01

    Full Text Available Vermicomposting technique in South Vietnam. Earthworms play a major role in organic matter transformation. The vermicomposting allows to combine several advantages: the management of diversified organic wastes, and the production of earthworms and vermicompost. Crop residues and other plant wastes mixed with animal manure from individual farms can be used. In South Vietnam, farmers are rearing some livestock and growing a few number of crop species. From several years, an increasing number of vermicomposting units were set in many farms from the Ho Chi Minh City region. Two kinds of infrastructure materials are used: baked clay blocks or bamboo stems with plastic covers. In South Vietnam, all conditions are pooled to ensure an efficient earthworm production: suitable climate, available organic wastes and materials to build the vermicomposting structures. Both field plot fertility and protein feed for livestock (pigs, poultry, etc. can be provided by rearing earthworms.

  5. The proving grounds: combat nursing in Vietnam.

    Science.gov (United States)

    Levasseur, Jeanne J

    2003-01-01

    The profession of nursing has been greatly influenced by war, and the heroic nature of the work of nursing is often emphasized during war. The purpose of this research was to examine the stories of nurses' experiences during combat in Vietnam and identify themes that would corroborate, refute, or expand prior historical research. A content analysis to determine recurrent themes was performed on 18 oral histories of military nurses who served in Vietnam that were previously collected and published. Analysis of these collections of oral histories was conducted, and thick quotes contextualize and substantiate the thematic claims. This research confirms the analysis of prior historical research on nursing in Vietnam by finding similar experiences recorded in oral histories and further claims that an authentic professional identity is often forged during the hardships and heroic opportunities of war.

  6. Coastal structural remains on the east coast of India: Evidence of maritime activities and their significance

    Digital Repository Service at National Institute of Oceanography (India)

    Tripati, S.

    in relation to the maritime history of the east coast of India. Keywords: Coastal structures, Ancient ports, Maritime activities, Structural remains, East coast of India. Introduction The Indian Peninsula has noticed a chain of development of seaports... number of ancient ports of India were located at the mouth of rivers and in case of lagoons at the outlets to the sea, where cargo can be handled easily and vessels can be anchored properly. Further, to corroborate the fact, the ancient Indian text...

  7. Invasion of Langebaan Lagoon, South Africa, by Mytilus ...

    African Journals Online (AJOL)

    In 1992 the invasive mussel Mytilus galloprovincialis began establishing beds on the centre sandbanks of Langebaan Lagoon. This global invader had previously been restricted to rocky shores along the South African coastline. In order to investigate the effect of the invasion on naturally-occurring communities, ...

  8. Trend of Heavy Metal Concentrations in Lagos Lagoon Ecosystem ...

    African Journals Online (AJOL)

    komla

    of Physical and Chemical Oceanography, Bar Beach, Victoria Island, Lagos,. Nigeria. *Corresponding author. Email: bayotitoloju@yahoo.com. Abstract. The distribution and occurrence of heavy metals in the sediment, water and benthic animals of the Lagos lagoon during the dry and rainy seasons were investigated over a ...

  9. Antibiotic resistance among heterotrophic bacteria in Lagos Lagoon ...

    African Journals Online (AJOL)

    Antibiotic-resistant bacteria in the aquatic environment are considered reservoirs for drug-resistant genes. Therefore, culturable heterotrophic bacteria isolated from Lagos Lagoon surface waters between 2011 and 2012 were screened for their susceptibility to 14 commonly used antibiotics belonging to six major classes.

  10. Augmenting Lagoon Process Using Reactivated Freeze-dried Biogranules.

    Science.gov (United States)

    Pishgar, Roya; Hamza, Rania Ahmed; Tay, Joo Hwa

    2017-02-24

    This study investigated the feasibility of using freeze-dried biogranules in lagoon basins. The effect of different operational conditions on treatment performance and detention time of granule-based lagoons was examined in a series of laboratory-scale batch studies. Optimal granule dosage was 0.1 g/L under anaerobic condition, resulting in 80-94% removal of 1000 mg/L chemical oxygen demand (COD) in 7-10 days. Under aerobic condition, granule dosage of 0.2 g/L achieved the best result for identical COD concentration. However, adequate amount of nutrients (optimal COD/N/P ratio of 100/13/0.8) should be supplied to encourage the growth of aerobic species. At optimal COD/N/P ratio, aerobic treatment interval significantly reduced to 2-3 days with corresponding COD removal efficiency of 88-92%. Inhibition of high concentrations of COD (5000 mg/L) and ammonia (480 mg/L NH4-N) was observed on microbial activity and treatment capacity of the biogranules. Mixing was a crucial measure to overcome mass transfer limitation. Onetime inoculation of lagoon with fresh granules was the best approach to achieve a satisfactory treatment efficiency. This study suggested that utilization of the biogranules is a feasible and sustainable technique for augmenting lagoon plants in terms of improved effluent quality and reduced retention time. Graphical Abstract ᅟ.

  11. Prospects of Conserving Wetlands Along the Mukwe Lagoon

    African Journals Online (AJOL)

    komla

    dilution of the pollutants. Most of the stream bed has been invaded by aquatic plants, causing the river bed narrowing in areas near the town, with the emergent aquatic vegetation dominated by Typha domingensis (cat-tail). Near the mouth of the stream where it enters the lagoon, free- floating species dominated by Pistia.

  12. Assessment of the pollution in Aghien lagoon and its tributaries ...

    African Journals Online (AJOL)

    This study seeks to characterize the types of pollution in Aghien lagoon and its tributaries. For the sampling, water was taken at a depth of 50 cm from the earth surface. Samples were analyzed by the spectrometric method of molecular absorption with sulfosalicylic acid for the nitrate, spectrophotometric method of molecular ...

  13. RTD (residence time distribution) predictions in large mechanically aerated lagoons.

    Science.gov (United States)

    Stropky, D; Pougatch, K; Nowak, P; Salcudean, M; Pagori, P; Gartshore, I; Yuan, J

    2007-01-01

    Mechanically aerated lagoons (used for wastewater treatment in the pulp and paper industry) are typically very large (>500,000 m3) and have complex three-dimensional fluid flow patterns due to mechanical agitation, sludge accumulation, internal baffling, and confined inlet/outlet flow channels. RTD data is frequently used for evaluation of hydraulic performance, however, obtaining accurate data with traditional dye measurements is a difficult and time-consuming process. Moreover, the mixing impact of factors such as aerator positions, sludge accumulation, and internal baffles would require a significant and costly number of local field measurements. Recent applications of CFD to mechanically aerated lagoons have helped engineers to understand the complex flow interactions. This paper provides a practical method for the evaluation of the hydraulic performance of large mechanically aerated lagoons using CFD. A method, based on random-walk Lagrangian particle tracking, has been developed to significantly shorten the computational time needed to produce RTD curves for these lagoons. Comparison of the particle method with the more conventional scalar transport yields excellent results. These methods allow wastewater engineers to combine their existing knowledge and expertise with the established power of CFD. The results quantify the hydraulic impact of different inlet/outlet configurations, aerator configurations, influent flow rates, and bottom sludge profiles.

  14. Boron, calcium and magnesium in Kavaratti lagoon water, Lakshadweep Archipelago

    Digital Repository Service at National Institute of Oceanography (India)

    Nasnolkar, C.M.; Salkar, V.R.; Shirodkar, P.V.; Abidi, S.A.H.

    1228.8 to 1319.8 mg kg sup(-1) (av. 1280.19 mg kg sup(-1)) and the salinity varied from 35.01 to 35.10 x 10 sup(-3) (av. 35.04 x 10 sup(-3)). The ratios of boron, calcium and magnesium to chlorinity in the lagoon water showed wide variation and were...

  15. Bacterial indicators of pollution of the Douala lagoon, Cameroon ...

    African Journals Online (AJOL)

    Methods: A total of eighty water samples were collected fortnightly from the lagoon at five stations from March to October 2005 and analysed for heterotrophic ... Eleven species of bacteria: Bacteroides fragilis, Proteus vulgaris, Klebsiella pneumoniae, E. coli, Enterococcus faecalis, Enterobacter aerogenes, Citrobacter ...

  16. Seasonal distribution of phytoplankton in the Aby lagoon system ...

    African Journals Online (AJOL)

    Seasonal variability of phytoplankton species composition, abundance and physical and chemical factors influencing phytoplankton dynamics were investigated in the Aby lagoon system, south-eastern Ivory Coast, covering the main climatic seasons in 2006–2007. Seasonal and spatial variability of nutrient concentrations ...

  17. APPLICATION OF SEDIMENT QUALITY GUIDELINES IN THE ASSESSMENT OF MANGROVE SURFACE SEDIMENT IN MENGKABONG LAGOON, SABAH, MALAYSIA

    Directory of Open Access Journals (Sweden)

    S. M. Praveena, M. Radojevic, M. H. Abdullah, A. Z. Aris

    2008-01-01

    Full Text Available There have been numerous sediment quality guidelines developed to monitor the sediments. Sediment quality guidelines are very useful to screen sediment contamination by comparing sediment contaminant concentration with the corresponding quality guideline, provide useful tools for screening sediment chemical data to identify pollutants of concern and prioritise problem sites and relatively good predictors of contaminations. However, these guidelines are chemical specific and do not include biological parameters. Aquatic ecosystems, including sediments, must be assessed in multiple components (biological data, toxicity, physicochemistry by using intregrated approaches in order to establish a complete and comprehensive set of sediment quality guidelines. Numerous sediment quality guidelines Washington Department of Ecology Sediment Quality Guideline, Australian and New Zealand Environment and Conservation Council, Swedish Environmental Sediment Quality, Screening Quick Reference Table, Portuguese Legislation on the Classification of Dredged Materials in Coastal Zones and Interim Sediment Quality Guideline for Hong Kong have been applied to the Mengkabong lagoon mangrove sediment and discussed. The most appropriate guideline that meets the prioritization criteria consistent with international initiatives and regulations is interim sediment quality values for Hong Kong. The guideline verifies that all the metals are below the Interim Sediment Quality Value-low. However, site-specific, biological testing and ecological analysis of exisiting benthics community structure related to sediment contamination are needed for final decision making in the case of Mengkabong lagoon.

  18. Recruitment and growth of two small-bodied resident fish species (Gobiidae and Atherinidae) in oligohaline, seasonally open lagoons.

    Science.gov (United States)

    Close, P G; Davies, P M; Trayler, K

    2010-04-01

    Spatio-temporal recruitment patterns, growth and survival of the Swan River goby Pseudogobius olorum and western hardyhead Leptatherina wallacei are described from two small, coastal lagoons on the south coast of Western Australia. In these lagoons, estuarine salinity dynamics were relatively stable over much of the autumn-spring period when freshwater inputs from rivers were reduced and there was no oceanic connection. Preflexion and flexion stages of both fish species contributed strongly to population size structure in downstream reaches, whereas upstream reaches were dominated by postflexion larvae and juvenile stages. Spawning of both species was protracted and largely asynchronous, although the episodic presence of stronger preflexion and flexion cohorts suggested some synchronized spawning had occurred. Comparison with estuarine conditions over this period provided evidence that synchronized spawning may be related to temperature and salinity variations from a combination of freshwater inputs and periods of marine exchange. Uninterrupted growth and the progression of cohorts through to juvenile stages were consistent with the generally stable estuarine conditions. Larval and juvenile stages of both species were also tolerant of abrupt changes in salinity and temperature, which occurred due to a non-seasonal oceanic connection. These findings were consistent with the euryhaline nature of adults of both species.

  19. Microplastic particles in sediments of Lagoon of Venice, Italy: First observations on occurrence, spatial patterns and identification

    Science.gov (United States)

    Vianello, A.; Boldrin, A.; Guerriero, P.; Moschino, V.; Rella, R.; Sturaro, A.; Da Ros, L.

    2013-09-01

    In order to improve knowledge of the identification, distribution and abundances of microplastic particles of 1 mm or less (S-MPPs) in the coastal area of the Mediterranean region, a preliminary monitoring survey was carried out in a transitional environment along the north-eastern Italian coasts, the Lagoon of Venice. S-MPPs were evaluated in sediments collected from 10 sites chosen in shallow areas variously affected by natural conditions and anthropogenic influences (i.e., landward stations influenced by freshwater inputs, seaward areas near sea inlets, and sites influenced by the presence of aquaculture farms, industry and city centers). S-MPPs, extracted from bulk sediments by density separation, were counted and identified by Fourier-Transform Infrared Micro-spectroscopy (μFT-IR). The μFT-IR process included automatic surface chemical mapping and references to an infrared library database to identify the compositional spectra of particles. S-MPPs were recovered from all samples - a fact which emphasizes their extensive distribution throughout the Lagoon. Total abundances varied from 2175 to 672 S-MPPs kg-1 d.w., higher concentrations generally being observed in landward sites. Of the ten polymer types identified, the most abundant, accounting for more than 82% of total S-MPPs, were polyethylene and polypropylene. The most frequent size (93% of observed microplastics) was in the range 30-500 μm. Total S-MPP values were significantly correlated with the finer sediment fraction and with the metal pollution index.

  20. Impacts of the 2011 Tsunami on Sediment Characteristics and Macrozoobenthic Assemblages in a Shallow Eutrophic Lagoon, Sendai Bay, Japan.

    Directory of Open Access Journals (Sweden)

    Gen Kanaya

    Full Text