Assessing the ecological condition of streams in a southeastern Brazilian basin using a probabilistic monitoring design

Prompt assessment and management actions are required if we are to reduce the current rapid loss of habitat and biodiversity worldwide. Statistically valid quantification of the biota and habitat condition in water bodies are prerequisites for rigorous assessment of aquatic biodiversity and habitat. We assessed the ecological condition of streams in a southeastern Brazilian basin. We quantified the percentage of stream length in good, fair, and poor ecological condition according to benthic macroinvertebrate assemblage. We assessed the risk of finding degraded ecological condition associated with degraded aquatic riparian physical habitat condition, watershed condition, and water quality. We describe field sampling and implementation issues encountered in our survey and discuss design options to remedy them. Survey sample sites were selected using a spatially balanced, stratified random design, which enabled us to put confidence bounds on the ecological condition estimates derived from the stream survey. The benthic condition index indicated that 62 % of stream length in the basin was in poor ecological condition, and 13 % of stream length was in fair condition. The risk of finding degraded biological condition when the riparian vegetation and forests in upstream catchments were degraded was 2.5 and 4 times higher, compared to streams rated as good for the same stressors. We demonstrated that the GRTS statistical sampling method can be used routinely in Brazilian rain forests and other South American regions with similar conditions. This survey establishes an initial baseline for monitoring the condition and trends of streams in the region.     

A comparative study on mesozooplankton abundance and diversity between a protected and an unprotected coastal area of Andaman Islands

The study was carried out to understand the variability in phytoplankton production (Chlorophyll a) and mesozooplankton diversity from two different shallow coastal regions of south Andaman viz. Port Blair Bay (PBB), the only real urban area among the islands and Mahatma Gandhi Marine National Park, a Marine Protected Area (MPA) at Wandoor. Seasonal sampling was carried out during the Northeast monsoon (NEM—November 2005), Intermonsoon (IM—April 2006), and Southwest monsoon (SWM—August 2006). Significant (P?<?0.05) seasonal variation was observed in the environmental variables at both the regions. Higher average chlorophyll a (Chl. a) and mesozooplankton standing stock were observed at PBB compared to MPA, but the seasonal variation observed was marginal at both the study areas. Chl. a showed a steep increasing gradient from outer to the inner regions of the PBB. The number of zooplankton taxa recorded at both areas was quite similar, but marked differences were noticed in their relative contribution to the total abundance. Eventhough the Copepoda dominated at both the areas, the non-copepod taxa differed significantly between the regions. Dominance of carnivores such as siphonophores and chaetognaths were noticed at PBB, while filter feeders such as appendicularians and decapod larvae were more abundant at MPA. A total of 20 and 21 copepod families was recorded from PBB and MPA, respectively. Eleven species of chaetognaths were observed as common at both areas. Larval decapods were found to be predominant at MPA with 20 families; whereas, at PBB, only 12 families were recorded. In the light of the recent reports on various changes occurring in the coastal waters of the Andaman Islands, it is suspected that the difference in Chl. a as well as the mesozooplankton standing stock and community structure observed between the two study areas may be related to the various anthropogenic events influencing the coastal waters.     

Study of Precision,Deviations and Uncertainty in the Design of the Strategic Noise Map of the Macrocenter of the City of Buenos Aires,Argentina

This article aims to discuss the influence of input data on the simulation model when designing Strategic Noise Maps. The studied noise map was made in the Macrocenter of the Independent City of Buenos Aires (Argentina), which has an approximated extension of 20 km² and about 500,000 inhabitants. The several input data for the model are analyzed, for their quality and the lack of some of them could affect the final result. Also, the evolution and validity of experimental measurements are analyzed when validating a simulated map. Finally, a study of the uncertainty of the map based on the input data is made, comparing it with the recommendations internationally adopted.     

Characterization of organic chemical contaminants in sediments from Jobos Bay, Puerto Rico

Jobos Bay, located on the southeastern coast of Puerto Rico, contains a variety of habitats including mangroves, seagrass meadows, and coral reefs. The watershed surrounding the bay includes a number of towns, agricultural areas, and the Jobos Bay National Estuarine Research Reserve (NERR). Jobos Bay and the surrounding watershed are part of a Conservation Effects Assessment Project (CEAP), involving the Jobos Bay NERR, the US Department of Agriculture, and the National Oceanic and Atmospheric Administration (NOAA) to assess the benefits of agricultural best management practices (BMPs) on the terrestrial and marine environments. As part of the Jobos Bay CEAP, NOAA collected sediment samples in May 2008 to characterize over 130 organic chemical contaminants. This paper presents the results of the organic contaminant analysis. The organic contaminants detected in the sediments included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and the pesticide DDT. PAHs at one site in the inner bay near a boat yard were significantly elevated; however, all organic contaminant classes measured were below NOAA sediment quality guidelines that would have indicated that impacts were likely. The results of this work provide an important baseline assessment of the marine environment that will assist in understanding the benefits of implementing BMPs on water quality in Jobos Bay.     

Dibenzazepin hydrochloride as a new spectrophotometric reagent for determination of hydrogen peroxide in plant extracts

A rapid, simple, accurate, and sensitive visible spectrophotometric method for the determination of trace amounts of hydrogen peroxide in acidic buffer medium is reported. The proposed method is based on the oxidative coupling of Ampyrone with dibenzazepin hydrochloride by hydrogen peroxide in the buffer medium of pH?4.0 which is catalyzed by ferrous iron. The blue-colored product formed with maximum absorption at 620?nm was found to be stable for 2?h. Beer's law is obeyed for hydrogen peroxide concentration in the range of 0.03-0.42?μg?ml(-1). The optimum reaction conditions and other important optical parameters are reported. The molar absorptive and Sandell's sensitivity are found to be 5.89?×?10(4)?mol(-1)?cm(-1) and 0.57?g/cm(2), respectively. The interference due to diverse ions and complexing agents was studied. The method is successfully applied to the determination of hydrogen peroxide in green plants satisfactorily.     

Apportionment of the airborne PM10 in Spain. Episodes of potential negative impact for human health

The particulate matter with an aerodynamic diameter less than or equal to 10 and 2.5 microns respectively (PM10 and PM2.5) constitutes one of the main air pollutants, which is currently regulated in Europe through Directive 2008/50/EC due to its proven harmful effects on human health. In this paper, the airborne PM10 samples collected in Zaragoza city during 2001-2009 were apportioned by statistical tools based on principal component analysis with absolute principal component scores (PCA-APCS). PM10 samples were characterized regarding their concentrations of polycyclic aromatic hydrocarbons (PAH) and water-soluble ions. PAH were analyzed by gas chromatography-mass spectrometry-mass spectrometry detection (GC-MS-MS) and ions were analyzed by ion chromatography. A total of five factors were identified by PCA-APCS corresponding to different anthropogenic and natural sources. This work was focused on analyzing in more detail those samples involving higher negative impact on human health, in particular, PM10 samples exceeding the daily PM10 limit value of 50 μg m(-3) according to Directive 2008/50/EC and samples with concentrations of benzo[a]pyrene (BaP) higher than the upper assessment threshold (BaP > 0.6 ng m(-3)) established by the Directive 2004/107/EC. Most of the exceedances of the daily PM10 limit value were associated with direct and indirect North-African long-range transport. During these exceedances, it was observed that anthropogenic pollution sources slightly decreased with regard to the natural sources. This indicated that episodes of high PM10 could have a natural origin associated with long-range transport from the African continent. On the contrary, those exceedances with regional contribution and samples with BaP concentrations higher than 0.6 ng m(-3) showed an important contribution of anthropogenic pollution sources increasing their negative impact on human health.     

Fragmentation of extracellular DNA by long-term exposure to radiation from uranium in aquatic environments

Persistent harmful scenarios associated with disposal of radioactive waste, high-background radiation areas and severe nuclear accidents are of great concern regarding consequences to both human health and the environment. Of particular concern is the extracellular DNA in aquatic environments contaminated by radiological substances. Strand breaks induced by radiation promote decrease in the transformation efficiency for extracellular DNA. The focus of this study is the quantification of DNA damage following long-term exposure (over one year) to low doses of natural uranium (an alpha particle emitter) to simulate natural conditions, since nothing is known about alpha radiation induced damage to extracellular DNA. A high-resolution Atomic Force Microscope was used to evaluate DNA fragments. Double-stranded plasmid pBS as a model for extracellular DNA was exposed to different amounts of natural uranium. It was demonstrated that low concentrations of U in water (50 to 150 ppm) produce appreciable numbers of double strand breaks, scaling with the square of the average doses. The importance of these findings for environment monitoring of radiological pollution is addressed.     

Foraminiferal biotopes and their distribution control in Ria de Aveiro (Portugal): a multiproxy approach

Ria de Aveiro, which is located in the centre of Portugal (40° 38′ N, 8° 45′ W), is a well-mixed and complex coastal lagoon that is separated from the sea by a sandy barrier and connects with the Atlantic through an artificial inlet. Tidal currents are the main factor controlling the lagoon’s hydrodynamics and, to a great extent, the sedimentary dynamic. The inner lagoonal zones receive input from several rivers and experience the pressure caused by the accumulation of organic matter and pollutants (namely, trace metals) from diverse anthropic activities. This paper is the first piece of work aiming to recognize, characterize and explain the main benthic foraminiferal biotopes in Ria de Aveiro. To provide a broad overview of this kind of setting, our results are compared to those of previous published studies conducted in similar transitional environments. The research is based on an investigation of 225 sites spread throughout this ecosystem. Utilizing a statistical approach, this study analyses the details of dead benthic foraminiferal assemblages composed of 260 taxa, the texture and composition (mineralogical and geochemical) of the sediment and physicochemical data. On the basis of the results of R-mode and Q-mode cluster analyses, several different biotopes can be defined as marsh biotope/near-marsh biotope; marginal urban/marginal urban mixing biotope; inner-outer lagoon biotope or enclosed lagoon; outer lagoon biotope, mixed sub-biotope; and outer lagoon, marine sub-biotope. These biotopes are related to foraminifera assemblages and substrate type and are influenced by local currents, water depth, chemical and physicochemical conditions, river or oceanic proximity, and anthropogenic impact, as evidenced by the mapping of the six factor loadings of the principal component analysis conducted herein. Based on a similar methodology of analysis as that applied in previous studies in the Lagoon of Venice, comparable biotypes were identified in Lagoon of Aveiro.     

Monitoring fish distributions along electrofishing segments

Electrofishing is widely used to monitor fish species composition and relative abundance in streams and lakes. According to standard protocols, multiple segments are selected in a body of water to monitor population relative abundance as the ratio of total catch to total sampling effort. The standard protocol provides an assessment of fish distribution at a macrohabitat scale among segments, but not within segments. An ancillary protocol was developed for assessing fish distribution at a finer scale within electrofishing segments. The ancillary protocol was used to estimate spacing, dispersion, and association of two species along shore segments in two local reservoirs. The added information provided by the ancillary protocol may be useful for assessing fish distribution relative to fish of the same species, to fish of different species, and to environmental or habitat characteristics.     

Water chemistry in 179 randomly selected Swedish headwater streams related to forest production,clear-felling and climate

From a policy perspective, it is important to understand forestry effects on surface waters from a landscape perspective. The EU Water Framework Directive demands remedial actions if not achieving good ecological status. In Sweden, 44 % of the surface water bodies have moderate ecological status or worse. Many of these drain catchments with a mosaic of managed forests. It is important for the forestry sector and water authorities to be able to identify where, in the forested landscape, special precautions are necessary. The aim of this study was to quantify the relations between forestry parameters and headwater stream concentrations of nutrients, organic matter and acid-base chemistry. The results are put into the context of regional climate, sulphur and nitrogen deposition, as well as marine influences. Water chemistry was measured in 179 randomly selected headwater streams from two regions in southwest and central Sweden, corresponding to 10 % of the Swedish land area. Forest status was determined from satellite images and Swedish National Forest Inventory data using the probabilistic classifier method, which was used to model stream water chemistry with Bayesian model averaging. The results indicate that concentrations of e.g. nitrogen, phosphorus and organic matter are related to factors associated with forest production but that it is not forestry per se that causes the excess losses. Instead, factors simultaneously affecting forest production and stream water chemistry, such as climate, extensive soil pools and nitrogen deposition, are the most likely candidates The relationships with clear-felled and wetland areas are likely to be direct effects.