Search

The environmental impact of microplastics is a challenging theme, especially under realistic experimental conditions. We investigated physiological responses to 0.1-1.0 μm PVC particles intake by the mussel Perna perna after a relative long-term exposure (90 days) at a less extreme concentration compared with previous studies (0.125 g/L). Microplastic intake was inferred by the presence of PVC in the feces of mussels, and physiological damages were assessed through ingestion rate, assimilation efficiency, growth rate, cellular and molecular biomarkers (lysosomal integrity, lipid peroxidation, and DNA damage), and condition index. All physiological responses showed nonsignificant effects of the microplastics on the exposed mussels. We suggest that, despite the experimental concentration of microplastics, mussels were able to acclimate to the exposure through their abilities for long-term recovery and tolerance to stresses. These data have positive implications for environmental health and in terms of human food resource because mussel farming is a worldwide practice that heavily relies on plastic materials, increasing the chances of microplastic exposure and mussels contamination. [ABSTRACT FROM AUTHOR]

Copyright of Desenvolvimento e Meio Ambiente is the property of Universidade Federal do Parana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The mole crab Emerita brasiliensis inhabits exposed sandy beaches, both reflective and dissipative, along the Atlantic coast of South America, where it usually attains high biomass and production. We assessed the effects of physical characteristics of beaches (mean grain size, beach width and slope) on production and turnover rate (P/B ratio) of E. brasiliensis. Six production and P/B ratio datasets, estimated with cohort-based and size-based methods, were gathered from studies carried out on subtropical (~25°S) and temperate beaches (~32°S). Based on the estimates available, general trends were identified. Production was positively related to the intermediate/dissipative conditions of wider beaches with finer sand grains and gentler slopes. P/B ratio was negatively related to grain size (mm) and positively related to beach width. These results suggest that P/B ratios also increase towards intermediate/dissipative features due to higher growth rate, as indicated by higher values of the curvature parameter of the von Bertalanffy growth function (K) in more benign conditions (wider beaches with finer grains). In addition, the recurrent pattern of size structure on intermediate/dissipative beaches, with high frequency of recruits, leads to higher P/B ratio estimates on these beaches than on reflective beaches. The relationship of production and P/B ratio with physical features, such as mean grain size, beach width and slope indicates that a ‘short-cut’ approach to estimate Emerita brasiliensis production is a promising prospect and, therefore, more data on the production of this species should be provided. [ABSTRACT FROM PUBLISHER]

Copyright of Ambiente & Sociedade is the property of Nepam Unicamp and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Butyltin compounds (BTs), including tributyltin (TBT) and its degradation products, dibutyltin and monobutyltin, have been found in a diversity of aquatic systems and causing toxic effects in target and nontarget organisms. They enter in coastal systems through different sources (as antifouling paints, industrial effluents, etc.) where they interact with biotic and abiotic components, and their distribution is commonly determined by the morphological and hydrodynamic conditions of the coastal systems. In this study, we discuss the contamination by BTs on a spatial scale (eight estuaries with three subareas each) and in different compartments of the estuaries (sediments, suspended particulate matter (SPM), and estuarine catfish tissues (liver and gills). Lower concentrations of BTs were found in the sediments (n.d. to 338 ng g) in comparison to studies before a ban of TBT in antifouling paints was enacted, mostly indicating an old input or preservation related with sediment properties and composition. For SPM samples (n.d. to 175 ng L) as well as in fish tissues (n.d. to 1426 ng g), the presence of these compounds was frequent, especially in the fish due to their movement throughout the estuaries and the potential to assess point sources of BTs. These results indicate that BTs persist in the environment, with variation in amounts between investigated estuaries and even at locations inside the same estuary, because of ideal preservation conditions, transport to remote areas, and input from different sources. [ABSTRACT FROM AUTHOR]

Hermit crabs respond to sensory cues that guide them toward limiting resources in marine and terrestrial environments. We examined the response of the common intertidal hermit crab Pagurus criniticornis (Dana, 1852) to simulated predation events on: (1) their principal shell donor Cerithium atratum (Born, 1778), (2) conspecifics, and (3) a sympatric bivalve; to test for the prevalence of olfactory specificity (i.e., attraction to a preferred gastropod species) or olfactory generality (i.e., attraction to a range of cues). Results showed that crabs were strongly attracted to gastropod baits but not to conspecifics or bivalves possibly reflecting greater motivation to acquire newly liberated resources than those more widely available (e.g., existing shells or food). We then examined the potential drivers of aggregative behavior by comparing the morphology and shell quality of attending individuals to an unbiased population. Although attending crabs were of a similar size and weight to the general population, their shells were of lower quality (adequacy, damage, and encrustation), suggesting that motivation to procure new shells is modulated by existing shell quality. The findings provide a clearer understanding of how hermit crabs acquire new resources and might have implications for the release and redistribution of other limiting resources within coastal environments. [ABSTRACT FROM AUTHOR]

Through history, population growth and anthropic activities have pressed and affected marine environments, causing impacts that were not always studied or reported. In this context, evaluate stakeholders perceptions of a particular region in Coastal Zones (CZs) can be useful for identifying environmental impacts that occurred in the past, especially in the absence of preterit data and effective monitoring. Engaging stakeholders in the discussion of local transformations may also contribute to the development of shared local management strategies regarding the knowledge and opinions of stakeholders about the place they live in. Thus, considering Araçá Bay as a case of study, this research aimed to understand preterit and present transformations on the Bay, through the perception of the people who live and visit the region for a long period of time. Data collected with interviews enabled the identification of events and factors that have induced changes in the region, mainly related to large enterprises and buildings that occurred from the second half of the twentieth century. Major impacts perceived by interviewees were changes in spatial configuration of the Bay, changes in hydrodynamic and sedimentary patterns, reduction of coastal vegetation areas and increased pollution. Some of these changes were also pointed by scientific studies or observed in historic aerial photographs, and were no totally predicted by EIA of related enterprise. Considering the importance of communities' perception and its use to better understand historical facts, preterit and present impacts derived from local human interventions, it is concluded that they are an important qualitative database and can be useful for the development of management strategies and for EIA analysis. [ABSTRACT FROM AUTHOR]

Top-down control is an important force modulating the abundance of prey and structuring marine communities. The harvested trigonal clam Tivela mactroides is hypothesized to be part of the diet of a variety of marine organisms, with its stock influencing predator abundance and being influenced by them. Here we analyzed the diet of potential predators of T. mactroides in Caraguatatuba Bay, northern coast of São Paulo State, Brazil, to identify the main consumers of this marine resource, and also to address the importance of this clam in the diet of each predator. Samples were taken year-round by trawls; all specimens collected were identified and measured and the food items identified and quantified. Twenty-one species consumed T. mactroides , whose importance in the diet varied greatly in both the volume ingested and the frequency of occurrence (pompano Trachinotus carolinus > blue crab Callinectes danae > starfish Astropecten marginatus ). Top-down influence on T. mactroides was also dependent on the abundance of consumers (yellow catfish Cathorops spixii > rake stardrum Stellifer rastrifer > barred grunt Conodon nobilis > A . marginatus ). Considering the mean volume ingested, the frequency of occurrence of T. mactroides in the diet, and the relative abundance of consumers, the predators that most influenced T. mactroides were T . carolinus , A. marginatus , and C . danae , in decreasing order. Large numbers of small-sized individuals of T . mactroides (<10 mm) were generally preyed upon by A . marginatus , which may have a stronger effect on clam abundance in comparison to C . danae and T . carolinus , which preyed upon larger clams. In conclusion, the results of this study indicate that predators' consumption of T. mactroides in Caraguatatuba Bay can influence its stocks, mainly due to the type and/or abundance of predator species, the volume and number of individuals of T. mactroides preyed upon, and the temporal variations in the abundance of predators. [ABSTRACT FROM AUTHOR]