Foraminifera as indicators of marine pollutant contamination on the inner continental shelf of southern Brazil

Analyses of living foraminiferal and environmental parameters near an outfall at Mar Grosso Beach (Laguna, SC, Brazil) demonstrate its usefulness as indicators of domestic sewage pollution. The low species diversity may be due to sand accumulation in the central part. Higher diversity was noted closer to the mouth of Laguna estuarine system where reduced salinity and higher temperatures indicate freshwater influence, suggesting a relationship between increased diversity and greater availability of terrestrial food. On the basis of foraminiferal diversity and average coliform count the higher values are closer to the mouth of the estuarine system and under the influence of the outfall. Due to the effect of local hydrodynamics, the particulate organic waste derived from the outfall does not settle down locally, and thus, do not accumulate nearby. Our hypothesis is that the fine material derived from the outfall is accumulating on the southwestern and northwestern parts of the beach.     

Offshore experiments on styrene spillage in marine waters for risk assessment

Within the context of risk evaluation of chemical spillages into the marine environment, this paper reports on an offshore experiment to study the behaviour of styrene spilled into sea under natural conditions and discusses theoretical approaches. Floating structures were used to enclose the spillage and the gaseous cloud formation, and dissolution processes were in situ monitored. The identification of spill risks for man and marine environment through GESAMP's hazard profile is described for styrene: Styrene is rated as a chemical with a significant health hazard that will float but also evaporate. However, monitoring of the water column in the experiments showed that the concentration of styrene in water during the first hour represents 50% of the product spilled. For the potentially exposed public, the GESAMP hazard rating recommends the closure of beaches and evacuation. The risk assessment developed from experimental data confirms this safety advice.     

The response of saltation to wind speed fluctuations

The response time of saltation to spatial or temporal wind speed fluctuations constitutes an important control parameter for aeolian sediment transport and deposition. In this paper, we present direct measurements of the response time obtained from several field experiments. The sand transport was studied using six small microphones arranged in a vertical profile and collocated with a sonic anemometer, a webcam and a cup anemometer tower. The webcam was coupled with the sonic anemometer via a personal computer and provides information on creeping and saltating grains with a sampling rate of 10 Hz. Sediment transport measurements were obtained over four periods. The Wiener filter, a signal processing technique, is used to obtain a discrete transfer function that relates the horizontal wind speed and the non‐intermittent sand transport. The transfer function can be established using an exponential function with a time constant or characteristic response time τ without time shift. The response time fluctuated between zero and 1·5 seconds depending on the turbulence intensity, the saltation activity, the measuring height and sampling rates. The Wiener filter coefficients suggest that the response of saltation to wind speed alterations is determined by more than one process. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of spatial resolution on regionalization of hydrological model parameters

Lack of availability of historical data series is one of the major hindrances in hydrological modelling. Regionalization of hydrological model parameters is one of the solutions to obtain the parameters for ungauged basins. Recently, lots of methodologies have been developed. They can be categorized as model calibration then fitting regression between model parameters and catchments characteristics, using some kind of transfer function. The aim of this study was to compare different regionalization methods as well as to look how the spatial resolution affects regionalization. In this study, a modified Lipschitz and monotony condition was used for regionalization. To identify the effect of the model resolution, the parameters of a distributed and semi‐distributed version of the Hydrologiska Byråns Vattenbalansavdelning (HBV) model were regionalized. The study was conducted at the upper Neckar catchment of southwest Germany. It has been found that the combination of Lipschitz and monotony condition has performed reasonably. It has been seen that the distributed model structure has outperformed the semi‐distributed model structure. It shows under present data conditions that higher model resolution can describe processes of ungauged basins reasonably. Copyright © 2011 John Wiley & Sons, Ltd.     

Extreme flows and unusual water levels near a Caribbean coral reef: was this a case of a “perfect storm”?

Observations of currents aimed to study the flow near a spawning aggregation reef, Gladden Spit off the coast of Belize, reveal unusually strong currents on 19–20 October 2009 (the current speed was over 1?m?s^?1, when the mean and standard deviation are 0.2?±?0.12?m?s^?1). During this short time, the water level was raised by 60–70?cm above normal in one place, but lowered by 10–20?cm in another location just 2?km away. The temperature dropped by over 2°C within a few hours. Analyses of local and remote sensing data suggest that a rare combination of an offshore Caribbean cyclonic eddy, a short-lived local tropical storm, and a Spring tide, all occurred at the same time and creating a “perfect storm” condition that resulted in the unusual event. High-resolution simulations and momentum balance analysis demonstrate how the unique shape of the coral reef amplified the coastal current through nonlinear flow–topography interactions. The suggested mechanism for the water level change is different than the classical wind-driven storm surge process. The study has implications for the influence of external forcing on mixing processes and physical–biological interactions near coral reefs.     

Inclined lidar observations of boundary layer aerosol particles above the Kongsfjord,Svalbard

An inclined lidar with vertical resolution of 0.4 m was used for detailed boundary layer studies and to link observations at Zeppelin Mountain (474 m) and Ny-Ålesund, Svalbard. We report on the observation of aerosol layers directly above the Kongsfjord. On 29 April 2007, a layer of enhanced backscatter was observed in the lowest 25 m above the open water surface. The low depolarization ratio indicated spherical particles. In the afternoon, this layer disappeared. The ultrafine particle concentration at Zeppelin and Corbel station (close to the Kongsfjord) was low. On 1 May 2007, a drying process in the boundary layer was observed. In the morning, the atmosphere up to Zeppelin Mountain showed enhanced values of the backscatter coefficient. Around noon, the top of the highly reflecting boundary layer decreased from 350 to 250 m. The top of the boundary layer observed by lidar was confirmed by radiosonde data.     

Seagrass ecophysiology meets ecological genomics: are we ready?

In March 2011, the Ecophysiology and Genetics Working Groups of the European Science Foundation COST Action ES 0906, entitled Seagrass Productivity: From Genes to Ecosystem Management, organized an exploratory workshop entitled “Linking Ecophysiology and Ecogenomics in Seagrass Systems”. The goal of the workshop was to discuss how to integrate comparative gene expression studies with physiological processes such as photosynthetic performance, carbon and nitrogen utilization and environmental adaptation. The main questions discussed for integrative research related to mechanisms of carbon utilization, light requirements, temperature effects and natural variation in pH and ocean acidification. It was concluded that the seagrass research community is still in the nascent stages of linking ecophysiology with genomic responses, as carbon and nitrogen metabolism of seagrasses have not been sufficiently well studied. Likewise, genomic approaches have only been able to assign meaningful interpretations to a handful of differentially expressed genes. Nevertheless, the way forward has been established.     

222Rn as Natural Tracer for LNAPL Recovery in a Crude Oil‐Contaminated Aquifer

The objective of this study was to investigate whether ²²²Rn in groundwater can be used as a tracer for light non‐aqueous phase liquid (LNAPL) quantification at a field site treated by dual‐phase LNAPL removal. After the break of a pipeline, 5 ha of soil in the nature reserve Coussouls de Crau in southern France was contaminated by 5100 m³ of crude oil. Part of this oil seeped into the underlying gravel aquifer and formed a floating oil body of about 3.9 ha. The remediation consists of plume management by hydraulic groundwater barriers and LNAPL extraction in the source zone. ²²²Rn measurements were performed in 21 wells in and outside the source zone during 15 months. In uncontaminated groundwater, the radon activity was relatively constant and remained always >11 Bq/L. The variability of radon activity measurements in wells affected by the pump‐and‐skim system was consistent with the measurements in wells that were not impacted by the system. The mean activities in wells in the source zone were, in general, significantly lower than in wells upgradient of the source zone, owing to partitioning of ²²²Rn into the oil phase. The lowest activities were found in zones with high non‐aqueous phase liquid (NAPL) recovery. LNAPL saturations around each recovery well were furthermore calculated during a period of high groundwater level, using a laboratory‐determined crude oil–water partitioning coefficient of 38.5 ± 2.9. This yielded an estimated volume of residual crude oil of 309 ± 93 m³ below the capillary fringe. We find that ²²²Rn is a useful and cheap groundwater tracer for finding zones of good LNAPL recovery in an aquifer treated by dual‐phase LNAPL removal, but that quantification of NAPL saturation using Rn is highly uncertain.