Mugil curema as a PAH bioavailability monitor for Atlantic west sub-tropical estuaries

This work aimed to evaluate the use of Mugil curema as a biomonitor for polycyclic aromatic hydrocarbon (PAH) bioavailability. Fish biliary metabolites from low-contaminated (Cananéia) and contaminated (Santos) Brazilian estuaries were analysed using a high-performance liquid chromatography apparatus coupled to fluorescence detectors connected in a series. In the Cananéia and Santos estuaries, total metabolite levels ranged from 0.85 to 34.4 μg g^? 1 of bile and from 4.06 to 528 μg g^? 1 of bile, respectively. Metabolite levels were not influenced by feeding status or sexual hormones (p < 0.05), thus suggesting that M. curema is a good biomonitor for PAH bioavailability. In estuarine regions, it is possible to sample both the male and female genders of this species in any reproductive period.     

Paleomagnetic and paleoclimatic investigation at Laguna Melincue (Pampean Plains,Argentina): preliminary results

Laguna Melincué is a shallow lake located in Santa Fe Province, Argentina (33°41′27.8″S, 61°31′36.5″W). The catchment area is around 1495 km² and it is located in the Pampean Plains. It was reduced to 678 km² by the construction of the San Urbano channel in 1941 and reconditioned in 1977, which was built to avoid floods. The floods are related to some El Niño episodes, with high precipitation events. The lake has been previously studied from different approaches, mainly to understand hydrological and climatic variations, but more multidisciplinary studies are needed to understand its complex hydrological situation. Here we present the first paleomagnetic and rock magnetic studies made on a short sediment core collected from the lake in order to contribute to identifying paleoclimatic proxies and to present the first paleomagnetic results for the site. Rock magnetic analyses suggest that the well-preserved magnetic mineralogy is dominated by pseudo single-domain (titano)magnetite and/or maghemite. The results also indicate that a stable characteristic remanent magnetisation can be isolated and thus the directions of the geomagnetic field may be obtained, providing evidence for the use of this lake for paleomagnetic and paleoenvironmental studies. Changes in magnetic grain size and concentration of magnetic minerals suggest environmental variations and changes in the lake level, which are consistent with historical reports. The paleomagnetic results agree well with Cals3k.3 model for inclination and declination of the geomagnetic field except for the dry period probably due to the fact that the core was extracted near the shore.     

Migration of total chromium and chloride anion in the Rocha River used for estimating degradation of agricultural soil quality at the Thiu Rancho zone

The Rocha River is a receptor to receive wastewater from household, hospital and industry, from where contaminants are transported in the river, affecting biodiversity and the ecosystem of the area. In this paper we estimated the maximum transport of total chromium and chloride anion by applying the analytical model of Ogata & Banks (1961), and the results obtained are grouped into three zones: Contaminated, transition, and uncontaminated. The analytical model was applied with 13 samples collected from the river piezometers installed near Rocha, where they are arranged in two lines, i.e. RH-1 to RH-6 as the first line and RH-9 to RH-12 as the second line. The total chromium concentrations range from 0.16 mg/L (RH-1) and 0.11 mg/L (RH-9) at the closest points to Rocha River, to 0.13 mg/L (RH-7) and 0.03 mg/L (RH-12) at the most remote points to the river. The advance of the pollutants does not exceed 50 meters with respect to the axis of the Rocha River.     

Influence of a breakwater on nearby rocky intertidal community structure

It is widely recognised that coastal-defence structures generally affect the structure of the assemblages they support, yet their impact on adjacent systems has been largely ignored. Breakwaters modify the nearby physical environment (e.g. wave action) suggesting a local impact on biological parameters. In the present study, an ACI (After-Control-Impact) design was used to test the general hypothesis that the artificial sheltering of an exposed coast has a strong effect on the structure and functioning of adjacent systems. The effects of a reduction in hydrodynamics were clear for a number of taxa and included the replacement of barnacles, limpets and frondose algae by an increasing cover of ephemeral algae. These effects were evident both at early and late successional stages. Results suggest that the artificial sheltering of naturally exposed coasts can have a strong impact promoting a shift from consumer- to producer-dominated communities, which has important ecological and energetic consequences for the ecosystem.     

Can PAHs influence Cu accumulation by salt marsh plants?

The presence of polycyclic aromatic hydrocarbons (PAHs) may change the mechanisms of metal uptake, thus influencing kinetics and extent of metal phytoextraction. Studies on the subject are scarce, particularly for salt marsh plants. The aim of this work was to investigate the effect of PAHs on the uptake of Cu by Halimione portulacoides, a plant commonly found in salt marshes. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, which were prepared with sediment and water from a salt marsh of the Cavado river estuary (NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed to those media during six days. Cu(2+) (as Cu(NO(3))(2)), 10(2) and 10(4)mugl(-1), was added to the media as well as 1.6mugl(-1) of the sixteen EPA priority PAHs (0.1mugl(-1) of each PAHs). Cu was assayed in solutions, sediments and different plant tissues before and after experiments. After exposure, photosynthetic efficiency and levels of chlorophylls were also measured, indicating that plant stress indicators were identical in all plants independently of the media to which the plants were exposed. PAHs influenced both the soluble Cu fraction and Cu uptake by plants. The amounts of metal accumulated in both roots and stems were significantly higher when the 10(4)mugl(-1) of Cu enriched elutriate was amended with PAHs. Thus, results suggest that PAHs may modify Cu solubility, the Cu sorption by plants and/or the passive penetration of Cu into the root cells. Therefore, the combined effects of different types of pollutants should be taken in consideration when studying the remediation potential of plants, namely in terms of phytoextraction.     

Positioning fisheries in a changing world

Marine capture fisheries face major and complex challenges: habitat degradation, poor economic returns, social hardships from depleted stocks, illegal fishing, and climate change, among others. The key factors that prevent the transition to sustainable fisheries are information failures, transition costs, use and non-use conflicts and capacity constraints. Using the experiences of fisheries successes and failures it is argued only through better governance and institutional change that encompasses the public good of the oceans (biodiversity, ecosystem integrity, sustainability) and societal values (existence, aesthetic and amenity) will fisheries be made sustainable.     

Anurans from the Candeleros Formation (?Cenomanian-Turonian) of west-central Argentina: new evidence for pipoid evolution

The fluvio-lacustrine deposits of the ?Cenomanian-Turonian Candeleros Formation in the northwestern fringe of Patagonia have yielded numerous remains of vertebrates, including anurans. A new, partially articulated immature specimen of a small pipimorph pipoid from the upper part of this unit is described herein. Although incompletely preserved, the morphology and proportions of the skeleton are strongly reminiscent of corresponding elements of the holotype of Avitabatrachus uliana from the lower section of the same formation at a nearby locality, thus suggesting that these specimens might represent the same, or a closely related, taxon. The new specimen is a metamorphosing individual: it has a zygapophyseal articulation between the sacrum and the neural arch of a postsacral vertebra that bears conspicuous transverse processes, and four pairs of ribs. These traits are not present in the available material of A. uliana, but they might have occurred within the normal range of variation of a single species. Although the generic and specific allocation of the new material is uncertain, a parsimony analysis performed to clarify the relationships of A. uliana supports a phylogenetic placement of this taxon outside the crown Pipidae. The evidence provided by the Candeleros anurans confirms the presence of stem pipids in Patagonia in the early Late Cretaceous.     

Testing the applicability of a Marine Biotic Index (AMBI) to assessing the ecological quality of soft-bottom benthic communities, in the South America Atlantic region

Recently, several monitoring programmes have been undertaken to evaluate the impact of different anthropogenic activities, upon a range of coastal ecosystems located in the South-western Atlantic. In the present contribution, the applicability of the AZTI's Marine Biotic Index (AMBI) is tested, to establish the benthic health of the ecosystem using these data sets. As the AMBI was created previously for use in European estuarine and coastal environments, its general applicability to new geographical locations is discussed. In general, the results are in agreement with those obtained using traditional univariate and multivariate methods. Some inconsistent results are observed, when low abundances and/or number of taxa are recorded in the samples. Moreover, when the macrofauna samples are dominated by large nematodes, the classification of the benthic ecosystem health using AMBI is not consistent with previous results achieved applying other statistical techniques. Thus, parallel to the application of this index to a wider extend, the complementary use of different indices and/or methods is recommended to assess confidently the environmental quality of a coastal area.