Ecological importance of sharks and rays in a structural foodweb analysis in southern Brazil

Abstract Understanding the trophic interactions and the position of species within a foodweb is crucial if we want to understand the dynamics of marine communities and the impact individual components of the community have on trophic network compartments. Recent studies have indicated sharks and rays are important elements within foodwebs. In this study, we evaluated the ecological importance of sharks and rays in a subtropical ecosystem off the coast of southern Brazil by using topological analyses. We tested the hypotheses that some elasmobranchs can be considered key elements within the foodweb, and that large predators have topological importance (act as keystones), so that, when large predators are excluded, mesopredator elasmobranchs occupy higher topological positions. Our results indicate that Galeocerdo cuvier, Carcharhinus obscurus, Carcharias taurus, Sphyrna lewini and S. zygaena are species with large ecological function values and may exert a powerful influence over lower levels. These issues need to be considered by conservation and fishery management groups since it appears that ecosystem integrity may be compromised by reductions in the populations of large predators. Carcharhinus obscurus, S. zygaena and Zapteryx brevirostris were found to be the elasmobranchs with largest values of centrality, and can, therefore, be considered key elements in the topological structure.

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Physico-chemical variability and heavy metal pollution of surface sediment in a non-channeled section of Dilúvio Stream (Southern Brazil) and the influence of channeled section in sediment pollution

Ambiente e Agua - An Interdisciplinary Journal of Applied Science ◽

10.4136/ambi-agua.2285 ◽

2019 ◽

Vol 14 (1) ◽

pp. 1 ◽

Cited By ~ 2

Author(s):

Pedro Alexandre Sodrzeieski ◽

Leonardo Capeleto de Andrade ◽

Tales Tiecher ◽

Flávio Anastácio de Oliveira Camargo

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Total Concentration ◽

Mineralogical Composition ◽

Sediment Pollution ◽

Anthropogenic Influence ◽

Southern Brazil ◽

Physico Chemical ◽

Chemical Variability ◽

The Impact

Dilúvio Stream flows through an area with a great population density in Porto Alegre, Southern Brazil. The anthropogenic influence in the surroundings impacted negatively the quality of the sediments of Dilúvio Stream and Lake Guaíba. This study evaluated the physico-chemical variability of surface sediments in a non-channeled section of Dilúvio Stream. Additionally, we compared the concentration of several heavy metals in this section with data from previous studies in the margins of Lake Guaíba near the outflow of Dilúvio Stream in order to evaluate the impact of urbanization on sediment pollution. The pH, bulk density, particle-size distribution, electrical conductivity, organic carbon, assimilable phosphorus, total nitrogen, mineralogical composition (X-ray diffractogram) and pseudo total concentration of several metals (Fe, Al, Ca, Mg, Na, K, Mn, Ba, Zn, V, As, Pb, Cu, Cr, Co, Ni, Cd, Mo, and Se) were evaluated. The results showed that the sediments in the non-channeled section of Dilúvio Stream are predominantly sandy, with heavy metal contents below the quality reference values. Quartz and feldspar predominated in all sites. The concentration of Zn, Pb, Cu, Cr, and Ni were lower than that observed in the margins of Lake Guaíba near the outflow of Dilúvio Stream, possibly due to pollution input throughout the channeled section. The Dilúvio Stream shows indications of an anthropogenic influence in the heavy metals concentration through the channeled area.

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Biomarkers responses in fish (Atherinella brasiliensis) of paranaguá bay, southern Brazil, for assessment of pollutant effects

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592013000100001 ◽

2013 ◽

Vol 61 (1) ◽

pp. 1-11 ◽

Cited By ~ 19

Author(s):

Ciro Alberto de Oliveira Ribeiro ◽

Alberto Katsumiti ◽

Patrícia França ◽

Jocieli Maschio ◽

Eliandra Zandoná ◽

...

Keyword(s):

Chemical Analysis ◽

Protected Areas ◽

Aquatic Organisms ◽

Southern Brazil ◽

Paranaguá Bay ◽

Fuel Oils ◽

Polycyclic Aromatic ◽

Biochemical Genetic ◽

Autumn And Winter ◽

The Impact

Paranaguá bay is a complex estuary located in southern Brazil containing three protected areas listed by UNESCO. Historically, the estuary has been affected by urban, industrial, agricultural and harbor activities, and occasional accidents. Specifically, the explosion of the Chilean ship Vicuña in December 2004 spilled methanol and crude and fuel oils which affected both protected and non-protected areas. The present study sought to investigate the pollution threat to aquatic organisms in order to evaluate the potential effects of pollutants. One hundred and twenty adult fish Atherinella brasiliensis were collected from different sites within Paranaguá estuary, including the harbor and open ocean, during summer, autumn and winter of 2005. Among the biomarkers, the somatic index, chemical analysis of bile, biochemical, genetic and morphological parameters were considered. Chemical analysis of bile showed a continuous bioavailability of polycyclic aromatic hydrocarbons (PAHs) according to proximity to the harbor site. The histopathological findings have demonstrated aconsiderable incidence of severe pathologies in the liver and gills, corroborated by biochemical disturbances and genetic damage. These findings indicate that more studies are necessary to evaluate both water quality and fish health so as to permit a better analysis of the impact of pollution in Paranaguá estuary.

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Modeling of Forest Ecosystem Degradation Due to Anthropogenic Stress: The Case of Rohingya Influx into the Cox’s Bazar–Teknaf Peninsula of Bangladesh

Environments ◽

10.3390/environments8110121 ◽

2021 ◽

Vol 8 (11) ◽

pp. 121

Author(s):

Mohammad Emran Hasan ◽

Li Zhang ◽

Riffat Mahmood ◽

Huadong Guo ◽

Guoqing Li

Keyword(s):

Forest Ecosystem ◽

Forest Ecosystems ◽

Forest Vegetation ◽

Rapid Decline ◽

Sudden Increase ◽

Refugee Crisis ◽

Anthropogenic Stress ◽

Ecosystem Integrity ◽

Humanitarian Response ◽

The Impact

Overdependence and cumulative anthropogenic stresses have caused world forests to decrease at an unprecedented rate, especially in Southeast Asia. The Cox’s Bazar–Teknaf Peninsula of Bangladesh is not an exception and follows the global deforestation trend. Despite being one of the country’s richest forest ecosystems with multiple wildlife sanctuaries, reserve forests, and influential wildlife habitats, the peninsula is now providing shelter for nearly one million Rohingya refugees. With the global deforestation trend coupled with excessive anthropogenic stresses from the Rohingya population, the forests in the peninsula are continuously deteriorating in terms of quality and integrity. In response to deforestation, the government invested in conservation efforts through afforestation and restoration programs, although the peninsula faced a refugee crisis in August 2017. The impact of this sudden increase in population on the forest ecosystem is large and has raised questions and contradictions between the government’s conservation efforts and the humanitarian response. Relocation of the refugees seems to be a lengthy process and the forest ecosystem integrity needs to be preserved; therefore, the degree of stresses, level of impacts, and pattern of deforestation are crucial information for forest conservation and protection strategies. However, there are a lack of quantitative analyses on how the forest ecosystem is deteriorating and what future results would be in both space and time. In this study, the impact of the sudden humanitarian crisis (i.e., Rohingya refugees) as anthropogenic stress in Cox’s Bazar–Teknaf peninsula has been spatiotemporally modeled and assessed using Sentinel-2 satellite imagery and other collateral data. Using the density and accessibility of the Rohingya population along with the land cover and other physiographic data, a multi-criteria evaluation (MCE) technique was applied through the Markov cellular automata technique to model the forest vegetation status. The impact of deforestation differs in cost due to variability of the forest vegetation covers. The study, therefore, developed and adopted three indices for assessment of the forest ecosystem based on the variability and weight of the forest cover loss. The spatial severity of impact (SSI) index revealed that out of 5415 ha of total degraded forest lands, 650 ha area would have the highest cost from 2017 to 2027. In the case of the ecosystem integrity (EI) index, a rapid decline in ecosystem integrity in the peninsula was observed as the integrity value fell to 1190 ha (2019) from 1340 ha (2017). The integrity is expected to further decline to 740 ha by 2027, if the stress persists in a similar fashion. Finally, the findings of ecosystem integrity depletion (EID) elucidated areas of 540 and 544 hectares that had a severe EID score of (−5) between 2017 and 2019 and 2017 and 2027, respectively. The displacement and refugee crisis is a recurrent world event that, in many cases, compromises the integrity and quality of natural space. Therefore, the findings of this study are expected to have significant global and regional implications to help managers and policymakers of forest ecosystems make decisions that have minimal or no impact to facilitate humanitarian response.

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Simulation of future climate scenarios and the impact on the water availability in southern Brazil

Acta Scientiarum Technology ◽

10.4025/actascitechnol.v43i1.56026 ◽

2021 ◽

Vol 43 ◽

pp. e56026

Author(s):

Gabriela Leite Neves ◽

Jorim Sousa das Virgens Filho ◽

Maysa de Lima Leite ◽

Frederico Fabio Mauad

Keyword(s):

Climate Change ◽

Water Balance ◽

Water Availability ◽

Meteorological Data ◽

Future Climate ◽

Climate Scenarios ◽

Southern Brazil ◽

Climate Data ◽

Intergovernmental Panel ◽

The Impact

Water is an essential natural resource that is being impacted by climate change. Thus, knowledge of future water availability conditions around the globe becomes necessary. Based on that, this study aimed to simulate future climate scenarios and evaluate the impact on water balance in southern Brazil. Daily data of rainfall and air temperature (maximum and minimum) were used. The meteorological data were collected in 28 locations over 30 years (1980-2009). For the data simulation, we used the climate data stochastic generator PGECLIMA_R. It was considered two scenarios of the fifth report of the Intergovernmental Panel on Climate Change (IPCC) and a scenario with the historical data trend. The water balance estimates were performed for the current data and the simulated data, through the methodology of Thornthwaite and Mather (1955). The moisture indexes were spatialized by the kriging method. These indexes were chosen as the parameters to represent the water conditions in different situations. The region assessed presented a high variability in water availability among locations; however, it did not present high water deficiency values, even with climate change. Overall, it was observed a reduction of moisture index in most sites and in all scenarios assessed, especially in the northern region when compared to the other regions. The second scenario of the IPCC (the worst situation) promoting higher reductions and dry conditions for the 2099 year. The impacts of climate change on water availability, identified in this study, can affect the general society, therefore, they must be considered in the planning and management of water resources, especially in the regional context

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A multibiomarker approach in rats to assess the impact of pollution on Sinos River, Southern Brazil

Brazilian Journal of Biology ◽

10.1590/s1519-69842010000600012 ◽

2010 ◽

Vol 70 (4 suppl) ◽

pp. 1223-1230 ◽

Cited By ~ 10

Author(s):

C. Rechenmacher ◽

AM. Siebel ◽

A. Goldoni ◽

CR. Klauck ◽

T. Sartori ◽

...

Keyword(s):

Oxidative Stress ◽

Water Quality ◽

Dna Damage ◽

Quality Analysis ◽

Microbiological Analysis ◽

Southern Brazil ◽

Anthropogenic Contamination ◽

Water Analyses ◽

The Impact ◽

The Relationship

The aim of this study was to determine the feasibility of combining water quality analysis with different biomarkers to characterise the relationship between anthropogenic contamination and biotic response in the Sinos River, southern Brazil. Wistar rats were studied using three biomarkers combined with physical, chemical and microbiological analysis to assess the effects of pollution at four sampling sites. The induction of oxidative stress was quantified by MDA levels in peripheral blood, lymphocyte DNA damage was determined using the comet assay, and histopathological changes were analysed in the liver. After sampling, animals were allowed to drink the river water during a 48 hours period. No increase in oxidative stress and DNA damage was observed. However, liver damage was observed in the animals exposed to water samples, indicating that the Sinos River is contaminated with hepatotoxic substances. Water analyses confirmed that water quality decreased downriver.

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A framework for ecosystem impacts assessment using an indicator approach

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2004.12.016 ◽

2005 ◽

Vol 62 (3) ◽

pp. 592-597 ◽

Cited By ~ 42

Author(s):

P.A. Livingston ◽

K. Aydin ◽

J. Boldt ◽

J. Ianelli ◽

J. Jurado-Molina

Keyword(s):

Fishery Management ◽

Ecosystem Impacts ◽

Implementation Challenges ◽

Management Actions ◽

Indicator Approach ◽

Research Organizations ◽

Ecosystem Indicators ◽

Ecosystem Level ◽

Associated Species ◽

The Impact

Abstract Assessment of the historical, present, and future states of marine ecosystems and the effects that humans and climate have on the state of an ecosystem are crucial to the scientific advice required to implement an ecosystem-based fishery management system. Management of federal groundfish fisheries in Alaska considers not just the target fishery, but also the possible impact those fisheries might have on other species and the ecosystem. Management actions have ranged from providing protection of endangered species in the region to preventing new fisheries from starting on key foodweb components such as forage fish. A scientific framework for providing ecosystem-based advice that puts the ecosystem first has been evolving over the past few years. This framework provides a way of assessing ecosystem factors that influence target species, the impact the target fishery may have on associated species, and ecosystem-level impacts of fishing. An indicator approach that describes ecosystem status, and trends and measures of human and climate influence has been developed to provide advice to fishery managers. This approach is now being expanded to utilize a variety of models to predict possible future trends in various ecosystem indicators. Future implementation challenges include the refinement of these predictive models, and the inclusion of climate into the models. Identification of sensitive and meaningful ecosystem indicators is also required before a more formalized decision-making process, one that includes ecosystem considerations, can be developed. Most important, the culture of fishery management and research organizations needs to change to embrace the ecosystem-based protections already mandated by various laws.

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The Use of Recycled Aggregates in Continuously Reinforced Concrete Pavements (CRCP)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.711.391 ◽

2013 ◽

Vol 711 ◽

pp. 391-395

Author(s):

Hans de Backer

Keyword(s):

Reinforced Concrete ◽

Los Angeles ◽

Drying Shrinkage ◽

Recycled Aggregates ◽

Concrete Layer ◽

Los Angeles Test ◽

Component Material ◽

Ecological Importance ◽

Natural Aggregates ◽

The Impact

The use of recycled aggregates in concrete has increased in recent decades. Increasing scarcity of natural aggregates and the growing ecological importance promote this evolution. The first test section in Belgium of a two-layer continuously reinforced concrete pavement (CRCP) with recycled aggregates in the substrate layer was built on the highway E34/N49 in 2007. Horizontal cracking at the level of the reinforcement showed up after only a few years. This is a problem which was never seen before in CRCP and was probably due to the use of recycled aggregates. Therefore it is important to understand the impact of recycled aggregates on concrete. Recycled aggregates are a two-component material consisting of natural aggregates and adhering mortar. The adhering mortar is more porous than the rock particles which insures a higher water absorption and lower density. In addition, they have a lower abrasion loss in the Los Angeles-test and less resistance against weather and temperature changes. This is due to, respectively, the less strong mortar content, and the large pores of recycled granulates. A first cause of horizontal cracking can be found in the results of high drying shrinkage, high creep and low modulus of elasticity. These properties insure larger tensions in the concrete layer. In combination with a lower tensile strength it is a possible cause for the horizontal cracking. In addition, the paper reports on laboratory testing concerning the properties of concrete with recycled aggregates and discusses an alternative method to determine the concrete mixture which takes the influence of the adhering mortar into account.

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The impacts of scallop dredging on sponge assemblages in the Gulf of Kalloni (Aegean Sea, northeastern Mediterranean)

ICES Journal of Marine Science ◽

10.1016/s1054-3139(03)00012-2 ◽

2003 ◽

Vol 60 (2) ◽

pp. 402-410 ◽

Cited By ~ 8

Author(s):

E Kefalas ◽

J Castritsi-Catharios ◽

H Miliou

Keyword(s):

Multivariate Analysis ◽

Fishery Management ◽

Aegean Sea ◽

Significant Loss ◽

Sponge Species ◽

Time Interval ◽

Suberites Domuncula ◽

Abundance Data ◽

Cliona Celata ◽

The Impact

Abstract Concerns have been raised on the impact of bottom-fishing activities in the shallow Gulf of Kalloni (Lesvos Island, Aegean Sea). Fishing with demersal gears was banned in 1995, but the Gulf was reopened in 1998 only for scallop dredging using the “lagamna” gear. Two series of samplings were done with this gear in 1998 and 1999 (October) before the beginning of scallop-fishing period (from November up to March), aiming to investigate possible changes in sponge assemblages. Sponges (Porifera) were the most abundant meso-megafaunal benthic organisms in the Gulf, besides scallops and other bivalves. Total abundance, number of species, species diversity, species richness and evenness of sponge assemblages reduced significantly from the year 1998 to 1999. The population of the excavating Cliona celata, the only infaunal sponge species found in the Gulf, decreased. Multivariate analysis on the abundance data of epibenthic sponge species revealed a clear separation of samples collected during the 2 years, indicating changes in the structure of sponge assemblages. The distinguishing species included a variety of growth forms: massive (Mycale massa, Suberites domuncula and Tethya citrina), lobose (Suberites massa, Tedania anhelans and Halichondria panicea), erect branching (Raspailia viminalis), encrusting (Crambe crambe) and cushion-shaped (Mycale contarenii and Chondrilla nuculla) sponges. Among these species, only S. massa increased its abundance in 1999. All others decreased. No significant loss of information occurred when multivariate analysis was applied to abundance data of genera or families. This comparative study demonstrated that the time interval between two consecutive scallop-fishing periods was insufficient for the recovery of sponge assemblages. It is concluded that scallop dredging causes long-term changes in the structure and biodiversity of sponge assemblages in the Gulf of Kalloni. An improved strategy of fishery management is required in future for the conservation of living resources in this Gulf.

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