Wilmington gray to blue

Wilmington is situated on the divide of two major watersheds, the Cape Fear River and the Atlantic Intracoastal Waterway. All surface waters in Wilmington drain to one of these two water bodies and are divided into two groups: tidal creeks and Cape Fear River tributaries. Cape Fear River tributaries drain directly to the Cape Fear River and comprise the western portion of Wilmington’s surface waters. Tidal creeks drain directly into the Atlantic Intracoastal Waterway and make up the eastern portion of Wilmington’s surface waters. (PDF contains 4 pages

Evaluation of a Commercial Enzyme Linked Immunosorbent Assay (ELISA) for the Determination of the Neurotoxin BMAA in Surface Waters

The neurotoxin ß-N-methylamino-L-alanine (BMAA) is suspected to play a role in Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Because BMAA seems to be produced by cyanobacteria, surface waters are screened for BMAA. However, reliable analysis of BMAA requires specialized and expensive equipment. In 2012, a commercial enzyme-linked immunosorbent assay (ELISA) for determination of BMAA in surface waters was released. This kit could enable fast and relatively cheap screening of surface waters for BMAA. The objective of this study was to determine whether the BMAA ELISA kit was suitable for the determination of BMAA concentrations in surface waters. We hypothesised that the recovery of spiked samples was close to 100% and that the results of unspiked sample analysis were comparable between ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. However, we found that recovery was higher than 100% in most spiked samples, highest determined recovery was over 400%. Furthermore, the ELISA gave a positive signal for nearly each tested sample while no BMAA could be detected by LC-MS/MS. We therefore conclude that in its current state, the kit is not suitable for screening surface waters for BMAA

A GIS model-based assessment of the environmental distribution of g-hexachlorocyclohexane in European soils and waters

The MAPPE GIS based multimedia model is used to produce a quantitative description of the behaviour of γ-hexachlorocyclohexane (γ-HCH) in Europe, with emphasis on continental surface waters. The model is found to reasonably reproduce γ-HCH distributions and variations along the years in atmosphere and soil; for continental surface waters, concentrations were reasonably well predicted for year 1995, when lindane was still used in agriculture, while for 2005, assuming severe restrictions in use, yields to substantial underestimation. Much better results were yielded when same mode of release as in 1995 was considered, supporting the conjecture that for γ-HCH, emission data rather that model structure and parameterization can be responsible for wrong estimation of concentrations. Future research should be directed to improve the quality of emission data. Joint interpretation of monitoring and modelling results, highlights that lindane emissions in Europe, despite the marked decreasing trend, persist beyond the provisions of existing legislation. An spatially-explicit multimedia modelling strategy was applied to describe the historical distribution of γ-HCH in European soils and surface waters

Impact of mining activities in the Upper Silesian Coal Basin on surface water and possibilities of its reduction

Due to the deposits of quality hard coal, the area of the Upper Silesian Coal Basin (USCB) has been one of the most industrialised regions in Europe for centuries. One of the most significant issues in terms of environmental impact and risks related to mining activities are the discharged mine waters. Mine water is pumped to the surface in great amount from mine workings of active underground mines both in Czech and Polish part of the USCB. In the past, the mine waters used to be discharged to nearby watercourses without systematic control of their amount and quality. It resulted in uncontrolled impacts on quality of the main rivers in the USCB. This is why a technically and economically demanding solution was adopted: discharging of mine (but also waste) waters through an artificial channel - so-called "Olza Collector" - directly to the Oder River, i.e. away of the Olza River and its minor tributaries. Automated control and dosing of waters to the Oder River depending on quality of the discharged waters and quality and quantity of the Oder surface water ensures maintaining of the total content of chlorides and sulphates in Oder below 500 mg/dm(3) with the efficiency of more than 90% of days in a year.Web of Science163696

Average seasonal changes in chlorophyll a in Icelandic waters

The standard algorithms used to derive sea surface chlorophyll a concentration from remotely sensed ocean colour data are based almost entirely on the measurements of surface water samples collected in open sea (case 1) waters which cover ~60% of the worlds oceans, where strong correlations between reflectance and chlorophyll concentration have been found. However, satellite chlorophyll data for waters outside the defined case 1 areas, but derived using standard calibrations, are frequently used without reference to local in situ measurements and despite well-known factors likely to lead to inaccuracy. In Icelandic waters, multiannual averages of 8-d composites of SeaWiFS chlorophyll concentration accounted for just 20% of the variance in a multiannual dataset of in situ chlorophyll a measurements. Nevertheless, applying penalized regression spline methodology to model the spatial and temporal patterns of in situ measurements, using satellite chlorophyll as one of the predictor variables, improved the correlation considerably. Day number, representing seasonal variation, accounted for substantial deviation between SeaWiFS and in situ estimates of surface chlorophyll. The final model, using bottom depth and bearing to the sampling location as well as the two variables mentioned above, explained 49% of the variance in the fitting dataset

Surface temperatures and temperature gradient features of the US Gulf Coast waters

Satellite thermal infrared data on the Gulf of Mexico show that a seasonal cycle exists in the horizontal surface temperature structure. In the fall, the surface temperatures of both coastal and deep waters are nearly uniform. With the onset of winter, atmospheric cold fronts, which are accompanied by dry, low temperature air and strong winds, draw heat from the sea. A band of cooler water forming on the inner shelf expands, until a thermal front develops seaward along the shelf break between the cold shelf waters and the warmer deep waters of the Gulf. Digital analysis of the satellite data was carried out in an interactive mode using a minicomputer and software. A time series of temperature profiles illustrates the temporal and spatial changes in the sea-surface temperature field

An approach to the use of macrophytes for monitoring standing waters

Under the EC Water Framework Directive (WFD), each Member State is required to devise a comprehensive national monitoring programme for surface waters, incorporating hydromorphological, physico-chemical and biological elements. This paper describes one aspect of the biota - the macrophyte flora - to classify standing waters and to monitor their water quality. The evolution of this method is described and suggestions for its future development are made

Macronutrient cycling in surface waters

The levels and relative proportions of macronutrients set the conditions for life in surface waters. Man-made disturbances to macronutrient cycling have caused environmental problems such as eutrophication, acidification and global change. In this thesis, macronutrient cycling was studied by performing spatial and temporal large-scale studies of aquatic, terrestrial and atmospheric national monitoring data. Trophic status was found to have a profound impact on nitrate-nitrogen (NO₃-N) concentrations in surface waters. Lakes and streams of the same trophic status displayed opposite NO₃-N patterns. These findings are of great importance when dealing with environmental assessment on the landscape scale, and an awareness of these patterns may also facilitate the design of sampling programs. Trophic status also seems important for trends in total phosphorus (TP) and total organic carbon (TOC) concentrations in boreal and alpine catchments. A temporal study of TP and TOC concentrations showed decreases in nutrient-poor catchments and increases in more nutrient-rich surface waters. Different responses of terrestrial organic matter production and decomposition to temperature increases may be responsible for the observed patterns. Consequently, continued global warming may lead to a stronger polarization between the nutrient-poor northern and the more nutrient-rich southern catchments. Further studies showed that nutrient conditions in soils and surface waters were strongly affected by atmospheric deposition. By using large data-sets on nutrient content in soils and nutrient concentrations in lakes, it was found that carbon to nitrogen ratios (C:N) in the organic soil layer and in lakes increased from the southern to the northern parts of Sweden, resulting in a strong relationship between soil and lake water C:N. The strong relationship was primarily due to the high correlation between nitrogen (N) in organic soil layer and lake N. Large-scale variations in soil C content were not strongly linked to lake C concentrations whereas soil N seemed to leach in the form of NO₃-N to lakes. By calculating catchment soil, lake and river mouth C stocks, it was estimated that about 10 % of Sweden's total terrestrial net ecosystem production is transported through lakes annually. This indicates that the amount of C exported from soils is substantial and that boreal soils maybe less important as a C sink as previously thought. Furthermore, it was found that the colored portion of C was selectively lost and that the decrease in water color was dependent on water retention time. This implies that under conditions predicted in future climate scenarios of increased precipitation, water reaching the seas will be more colored than today. The results from this thesis highlight the importance of atmospheric N deposition and trophic status to macronutrient cycling in both terrestrial and aquatic ecosystems

Silicon isotopes as a tracer for silicate utilization in the Peruvian upwelling

EGU2011-6081 Natural stable isotopes are a powerful tool in marine sciences to investigate biological processes, such as present and past nutrient utilization. In this study we present the first dissolved silicon isotope data in the upwelling area off Peru, where one of the world’s largest Oxygen Minimum Zones (OMZ) is located. Silicon is the most important component required for phytoplankton (diatom) growth, which dominates primary productivity in this region. Stable Si isotopes are fractionated during diatom growth in that the lighter Si isotopes are preferentially incorporated into diatoms with a fractionation factor of -1.1 promille. The Si isotope composition of dissolved silicic acid of the corresponding surface waters is therefore left isotopically heavier. The Si isotope composition, 30Si/28Si, is expressed as δ30Si values, which stand forh deviations from a given standard (NBS28). Investigation of the dissolved seawater Si isotope composition thus provides a measure for the utilization and, combined with information on the Si isotope composition of the water masses upwelling off Peru, it is a measure for the supply pathways of Si to the coastal upwelling centres. Surface waters on the shelf off Peru are mainly fed by the Equatorial Undercurrent, which mainly consists of waters originating from the western and Central Pacific and which has a characteristic δ30Si of +1.5 promille. In areas and during phases of intense upwelling the fractionation of Si isotopes was observed to be weaker due to upwelling-driven supply of less fractionated Si (δ30Si = 1.7 promille, from water depths of around 100-150 m, whereas under weak upwelling conditions fractionation is higher (δ30Si ~3 promille due to a more complete utilization of the available dissolved silicate. The distribution of dissolved δ30Si correlates strongly with particulate biogenic silicate (opal) concentrations in that highest opal concentrations in the surface waters show the lowest δ30Si values thus strongest upwelling intensity. The most extreme δ30Si values in surface waters (δ30Si = 4.5 promille are observed offshore where silicic acid concentrations are nearly zero. Furthermore we compare the δ30Si data with the dissolved nitrogen isotope distribution, which in addition to nitrate utilization is mainly influenced by denitrification and annamox processes in the OMZ. Combined silicon and nitrogen isotope compositions can thus help to disentangle different fractionation processes within the nitrogen cycle