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1.
An Acad Bras Cienc ; 92 Suppl 1: e20181245, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348409

RESUMO

Several countries included the assessment of environmental drift contamination risk for the registration of pesticides. This practice is not yet totality effective in Brazil; however, due to the large number of pesticides in use, it is important to identify the real contamination risk during pesticide spraying. Therefore, this study determined the indices of environmental risks for exposure to drift from terrestrial applications of fungicides, herbicides, and insecticides that are used in soybean crops under Brazilian climate conditions and established buffer zones for the application of these products. Based on the three prediction drift models for soybeans in Brazil, risk indices were computed for aquatic organisms and terrestrial organisms according to the modelling procedures proposed by the POCER (Pesticide Occupation and Environmental Risk) and HAIR (Harmonized Environmental Indicators for Pesticide Risk) methodologies. In general, aquatic organisms are the most sensitive to drift contamination, being chlorothalonil, trifluralin and chlorpyrifos the ones that presented the higher risk indexes. No risk was found for earthworms; in contrast, the insecticides chlorpyrifos, spinosad and thiamethoxam presented risks to bees regardless of the nozzle (droplet size) used for the determination of the drift curve, resulting in the demand for different buffer zones.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Produtos Agrícolas , Monitoramento Ambiental/métodos , Praguicidas/toxicidade , Soja , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/classificação , Praguicidas/classificação , Medição de Risco
2.
Science ; 367(6481): 1035-1038, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32108111

RESUMO

Ecological differentiation is correlated with taxonomic diversity in many clades, and ecological divergence is often assumed to be a cause and/or consequence of high speciation rate. However, an analysis of 30,074 genera of living marine animals and 19,992 genera of fossil marine animals indicates that greater ecological differentiation in the modern oceans is actually associated with lower rates of origination over evolutionary time. Ecologically differentiated clades became taxonomically diverse over time because they were better buffered against extinction, particularly during mass extinctions, which primarily affected genus-rich, ecologically homogeneous clades. The relationship between ecological differentiation and taxonomic richness was weak early in the evolution of animals but has strengthened over geological time as successive extinction events reshaped the marine fauna.


Assuntos
Organismos Aquáticos/classificação , Biodiversidade , Extinção Biológica , Especiação Genética , Organismos Aquáticos/genética , Fósseis , Oceanos e Mares
3.
Nat Commun ; 11(1): 692, 2020 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041961

RESUMO

Genetic diversity is estimated to be declining faster than species diversity under escalating threats, but its spatial distribution remains poorly documented at the global scale. Theory predicts that similar processes should foster congruent spatial patterns of genetic and species diversity, but empirical studies are scarce. Using a mined database of 50,588 georeferenced mitochondrial DNA barcode sequences (COI) for 3,815 marine and 1,611 freshwater fish species respectively, we examined the correlation between genetic diversity and species diversity and their global distributions in relation to climate and geography. Genetic diversity showed a clear spatial organisation, but a weak association with species diversity for both marine and freshwater species. We found a predominantly positive relationship between genetic diversity and sea surface temperature for marine species. Genetic diversity of freshwater species varied primarily across the regional basins and was negatively correlated with average river slope. The detection of genetic diversity patterns suggests that conservation measures should consider mismatching spatial signals across multiple facets of biodiversity.


Assuntos
Biodiversidade , Peixes/genética , Variação Genética , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , DNA Mitocondrial/genética , Bases de Dados Genéticas , Meio Ambiente , Peixes/classificação , Geografia
4.
Arch Microbiol ; 202(4): 859-873, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31894394

RESUMO

Network analysis has contributed to studies of the interactions of microorganisms and the identification of key populations. However, such analysis has rarely been conducted in the study of reservoir bacterioplankton communities. This study investigated the bacterioplankton community composition in the surface water of the Danjiangkou Reservoir using the Illumina MiSeq sequencing platform. We observed that the bacterioplankton community primarily consisted of 27 phyla and 336 genera, including Actinobacteria, Proteobacteria, and Bacteroidetes, demonstrating the richness of the community composition. Redundancy analysis of the bacterioplankton communities and environmental variables showed that the total nitrogen (TN), pH, chemical oxygen demand (COD), and permanganate index (CODMn) were important factors affecting the bacterioplankton distribution. Network analysis was performed using the relative abundances of bacterioplankton based on the phylogenetic molecular ecological network (pMEN) method. The connectivity of node i within modules (Zi), the connectivity of node i among modules (Pi), and the number of key bacteria were high at the Taizishan and Heijizui sites, which were associated with higher TN contents than at the other sites. Among the physicochemical properties of water, TN, ammonia nitrogen (NH4-N), pH, COD, and dissolved oxygen (DO) might have great influences on the functional units of the bacterial communities in bacterioplankton molecular networks. This study improves the understanding of the structure and function of bacterioplankton communities in the Danjiangkou Reservoir.


Assuntos
Organismos Aquáticos/classificação , Bactérias/classificação , Bactérias/genética , Água Doce/microbiologia , Plâncton/classificação , Plâncton/genética , Biodiversidade , China , Demografia , Água Doce/química , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Plâncton/microbiologia
5.
Syst Parasitol ; 97(1): 1-23, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31912420

RESUMO

We provide molecular data (cox1, 18S rDNA and 28S rDNA) for 17 acanthocephalan species and 20 host-parasite combinations from Australian marine teleosts collected from off Queensland, Australia. Fourteen of these acanthocephalans are characterised with molecular data for the first time and we provide the first molecular data for a species of each of the genera Heterosentis Van Cleave, 1931, Pyriproboscis Amin, Abdullah & Mhaisen, 2003 and Sclerocollum Schmidt & Paperna, 1978. Using 18S and 28S rDNA sequences, the phylogenetic position of each newly sequenced species is assessed with both single-gene and concatenated 18S+28S maximum likelihood and Bayesian inference analyses. Additional phylogenetic analyses focusing on the genus Rhadinorhynchus Lühe, 1912 and related lineages are included. Our phylogenetic results are broadly consistent with previous analyses, recovering previously identified inconsistencies but also providing new insights and necessitating taxonomic action. We do not find sufficient evidence to recognise the Gymnorhadinorhynchidae Braicovich, Lanfranchi, Farber, Marvaldi, Luque & Timi, 2014 as distinct from the Rhadinorhynchidae Lühe, 1912. The family Gymnorhadinorhynchidae and its sole genus, Gymnorhadinorhynchus Braicovich, Lanfranchi, Farber, Marvaldi, Luque & Timi, 2014, are here recognised as junior synonyms of Rhadinorhynchidae and Rhadinorhynchus, respectively. The two species currently assigned to Gymnorhadinorhynchus are recombined as Rhadinorhynchus decapteri (Braicovich, Lanfranchi, Farber, Marvaldi, Luque & Timi, 2014) n. comb. and Rhadinorhynchus mariserpentis (Steinauer, Garcia-Vedrenne, Weinstein & Kuris, 2019) n. comb. In all of our analyses, Rhadinorhynchus biformis Smales, 2014 is found basal to the Rhadinorhynchidae + Transvenidae Pichelin & Cribb, 2001, thus resulting in a paraphyletic Rhadinorhynchidae. It appears that R. biformis may require a new genus and family; however, morphological data for this species are currently insufficient to adequately distinguish it from related lineages, thus we defer the proposal of any new higher-rank names for this species. Species of the genus Sclerocollum, currently assigned to the Cavisomidae Meyer, 1932, are found nested within the family Transvenidae. We transfer the genus Sclerocollum to the Transvenidae and amend the diagnosis of the family accordingly. The genera Gorgorhynchoides Cable & Linderoth, 1963 and Serrasentis Van Cleave, 1923, currently assigned to the Rhadinorhynchidae, are supported as sister taxa and form a clade in the Polymorphida. We transfer these genera and Golvanorhynchus Noronha, Fabio & Pinto, 1978 to an emended concept of the Isthomosacanthidae Smales, 2012 and transfer this family to the Polymorphida. Lastly, Pyriproboscis heronensis (Pichelin, 1997) Amin, Abdullah & Mhaisen, 2003, currently assigned to the Pomphorhynchidae Yamaguti, 1939, falls under the Polymorphida in our analyses with some support for a sister relationship with the Centrorhynchidae Van Cleave, 1916. As this species clearly does not belong in the Pomphorhynchidae and is morphologically and molecularly distinct from the lineages of the Polymorphida, we propose the Pyriprobosicidae n. fam. to accommodate it.


Assuntos
Acantocéfalos/classificação , Acantocéfalos/genética , Organismos Aquáticos/parasitologia , Peixes/parasitologia , Filogenia , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Queensland , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Especificidade da Espécie
6.
Arch Microbiol ; 202(4): 815-824, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31844948

RESUMO

Kiloniella laminariae is a true marine bacterium and the first member of the family and order, the Kiloniellaceae and Kiloniellales. K. laminariae LD81T (= DSM 19542T) was isolated from the marine macroalga Saccharina latissima and is a mesophilic, typical marine chemoheterotrophic aerobic bacterium with antifungal activity. Phylogenetic analysis of 16S rRNA gene sequence revealed the similarity of K. laminariae LD81T not only with three validly described species of the genus Kiloniella, but also with undescribed isolates and clone sequences from marine samples in the range of 93.6-96.7%. We report on the analysis of the draft genome of this alphaproteobacterium and describe some selected features. The 4.4 Mb genome has a G + C content of 51.4%, contains 4213 coding sequences including 51 RNA genes as well as 4162 protein-coding genes, and is a part of the Genomic Encyclopaedia of Bacteria and Archaea (GEBA) project. The genome provides insights into a number of metabolic properties, such as carbon and sulfur metabolism, and indicates the potential for denitrification and the biosynthesis of secondary metabolites. Comparative genome analysis was performed with K. laminariae LD81T and the animal-associated species Kiloniella majae M56.1T from a spider crab, Kiloniella spongiae MEBiC09566T from a sponge as well as Kiloniella litopenai P1-1 from a white shrimp, which all inhabit quite different marine habitats. The analysis revealed that the K. laminariae LD81T contains 1397 unique genes, more than twice the amount of the other species. Unique among others is a mixed PKS/NRPS biosynthetic gene cluster with similarity to the biosynthetic gene cluster responsible for the production of syringomycin.


Assuntos
Alphaproteobacteria/genética , Organismos Aquáticos/genética , Genômica , Filogenia , Alphaproteobacteria/classificação , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/microbiologia , Proteínas de Bactérias/genética , Composição de Bases , Feófitas/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie
7.
Ecotoxicol Environ Saf ; 188: 109881, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31704324

RESUMO

N,N-diethyl-meta-toluamide (DEET) is the most widely used active ingredient in commercial insect repellents. In addition to its adverse effects in insects, DEET can affect non-target organisms in surface water systems. Nevertheless, the aquatic life criteria of DEET are not available. This study conducted both acute and chronic toxicity tests on DEET in native Chinese aquatic species, and derived its criterion maximum concentration (CMC) and criterion continuous concentration (CCC). The determined CMC and CCC of DEET were 21.53 and 0.52 mg/L, respectively. The toxicity data indicated that DEET exposure posed a higher toxicity to some algae than other aquatic species. Compared with other insect repellents, DEET exposure posed a moderate toxicity to aquatic species. Therefore, the exposure concentration of DEET in Chinese surface water was collected to assess the potential ecological risk. The preliminary ecological risk assessment showed that DEET posed negligible risk to aquatic ecosystems in China. However, considering its toxic effects on the growth and reproduction to aquatic organisms, the ecological risk posed by DEET is worth further concern.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , DEET/toxicidade , Exposição Ambiental/análise , Repelentes de Insetos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/crescimento & desenvolvimento , Organismos Aquáticos/fisiologia , China , DEET/análise , Repelentes de Insetos/análise , Medição de Risco , Especificidade da Espécie , Testes de Toxicidade , Poluentes Químicos da Água/análise
8.
Protist ; 171(1): 125710, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31884404

RESUMO

This study set out to bolster morphological and molecular datasets of marine gregarine apicomplexans. Gregarines were sampled from the Sea of Japan and Northwest Pacific from cirratuliform polychaetes (Acrocirridae, Cirratulidae, and Flabelligeridae), as well as sipunculids. Trophozoites (feeding stages) were gathered for identification using light microscopy, scanning electron microscopy, and transmission electron microscopy. Cells were also collected for molecular phylogenetic analysis using 18S rDNA and 28S rDNA. As a result, three new species of Selenidium, S. planusae n. sp., S. validusae n. sp., and S. pyroidea n. sp. were described, and additional morphological and genetic data were gathered for an existing species, S. orientale; and Trollidium was established as a new genus. Trollidium akkeshiense n. gen. n. sp. possessed a unique, unsymmetrical organization of microtubules running the longitudinal length of one side of the trophozoite, corresponding to a zig-zag pattern of epicytic (surface) folds, and a flicking pattern of movement. Phylogenetic analyses of 18S rDNA and 28S rDNA showed that these portions of the ribosomal operon are able to resolve some relationships among Selenidium, while other lineages including Trollidium akkeshiense n. gen. n. sp. appeared to be highly influenced by long branch attraction. High evolutionary rates along the ribosomal operon of gregarines may hinder this marker from resolving deeper nodes among early apicomplexans.


Assuntos
Apicomplexa/classificação , Apicomplexa/genética , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Filogenia , DNA Ribossômico/genética , Oceano Pacífico , Especificidade da Espécie
9.
PLoS One ; 14(12): e0226547, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31869356

RESUMO

Benthic invertebrates are the most commonly used organisms used to assess ecological status as required by the EU Water Framework Directive (WFD). For WFD-compliant assessments, benthic invertebrate communities are sampled, identified and counted. Taxa × abundance matrices are used to calculate indices and the resulting scores are compared to reference values to determine the ecological status class. DNA-based tools, such as DNA metabarcoding, provide a new and precise method for species identification but cannot deliver robust abundance data. To evaluate the applicability of DNA-based tools to ecological status assessment, we evaluated whether the results derived from presence/absence data are comparable to those derived from abundance data. We analysed benthic invertebrate community data obtained from 13,312 WFD assessments of German streams. Broken down to 30 official stream types, we compared assessment results based on abundance and presence/absence data for the assessment modules "organic pollution" (i.e., the saprobic index) and "general degradation" (a multimetric index) as well as their underlying metrics. In 76.6% of cases, the ecological status class did not change after transforming abundance data to presence/absence data. In 12% of cases, the status class was reduced by one (e.g., from good to moderate), and in 11.2% of cases, the class increased by one. In only 0.2% of cases, the status shifted by two classes. Systematic stream type-specific deviations were found and differences between abundance and presence/absence data were most prominent for stream types where abundance information contributed directly to one or several metrics of the general degradation module. For a single stream type, these deviations led to a systematic shift in status from 'good' to 'moderate' (n = 201; with only n = 3 increasing). The systematic decrease in scores was observed, even when considering simulated confidence intervals for abundance data. Our analysis suggests that presence/absence data can yield similar assessment results to those for abundance-based data, despite type-specific deviations. For most metrics, it should be possible to intercalibrate the two data types without substantial efforts. Thus, benthic invertebrate taxon lists generated by standardised DNA-based methods should be further considered as a complementary approach.


Assuntos
Organismos Aquáticos/classificação , Biodiversidade , Evolução Biológica , Invertebrados/classificação , Rios , Animais , Organismos Aquáticos/citologia , Organismos Aquáticos/genética , Organismos Aquáticos/crescimento & desenvolvimento , Bases de Dados Factuais/tendências , Ecossistema , Monitoramento Ambiental , Extinção Biológica , Alemanha , Invertebrados/citologia , Invertebrados/genética , Invertebrados/crescimento & desenvolvimento , Dinâmica Populacional/tendências
10.
PLoS One ; 14(12): e0226527, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841568

RESUMO

DNA-based identification through the use of metabarcoding has been proposed as the next step in the monitoring of biological communities, such as those assessed under the Water Framework Directive (WFD). Advances have been made in the field of metabarcoding, but challenges remain when using complex samples. Uneven biomass distributions, preferential amplification and reference database deficiencies can all lead to discrepancies between morphological and DNA-based taxa lists. The effects of different taxonomic groups on these issues remain understudied. By metabarcoding WFD monitoring samples, we analyzed six different taxonomic groups of freshwater organisms, both separately and combined. Identifications based on metabarcoding data were compared directly to morphological assessments performed under the WFD. The diversity of taxa for both morphological and DNA-based assessments was similar, although large differences were observed in some samples. The overlap between the two taxon lists was 56.8% on average across all taxa, and was highest for Crustacea, Heteroptera, and Coleoptera, and lowest for Annelida and Mollusca. Taxonomic sorting in six basic groups before DNA extraction and amplification improved taxon recovery by 46.5%. The impact on ecological quality ratio (EQR) scoring was considerable when replacing morphology with DNA-based identifications, but there was a high correlation when only replacing a single taxonomic group with molecular data. Different taxonomic groups provide their own challenges and benefits. Some groups might benefit from a more consistent and robust method of identification. Others present difficulties in molecular processing, due to uneven biomass distributions, large genetic diversity or shortcomings of the reference database. Sorting samples into basic taxonomic groups that require little taxonomic knowledge greatly improves the recovery of taxa with metabarcoding. Current standards for EQR monitoring may not be easily replaced completely with molecular strategies, but the effectiveness of molecular methods opens up the way for a paradigm shift in biomonitoring.


Assuntos
Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Código de Barras de DNA Taxonômico/métodos , Monitorização de Parâmetros Ecológicos/métodos , Invertebrados/classificação , Invertebrados/genética , Animais , Anelídeos/classificação , Anelídeos/genética , Biodiversidade , Biota/genética , Crustáceos/classificação , Crustáceos/genética , DNA/análise , Bases de Dados Factuais , Água Doce/química , Moluscos/classificação , Moluscos/genética , Reprodutibilidade dos Testes , Qualidade da Água/normas
11.
PLoS One ; 14(12): e0226410, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31851700

RESUMO

Current research revealed distinct changes in ecosystem functions, and thus in ecosystem stability and resilience, caused by changes in community structure and diversity loss. Benthic species play an important role in benthic-pelagic coupling, such as through the remineralization of deposited organic material, and changes to benthic community structure and diversity have associated with changes in ecosystem functioning, ecosystem stability and resilience. However, the long-term variability of traits and functions in benthic communities is largely unknown. By using abundance and bioturbation potential of macrofauna samples, taken along a transect from the German Bight towards the Dogger Bank in May 1990 and annually from 1995 to 2017, we analysed the taxonomic and trait-based macrofauna long-term community variability and diversity. Taxonomic and trait-based diversity remained stable over time, while three different regimes were found, characterised by changes in taxonomic and trait-based community structure. Min/max autocorrelation factor analysis revealed the climatic variables sea surface temperature (SST) and North Atlantic Oscillation Index (NAOI), nitrite, and epibenthic abundance as most important environmental drivers for taxonomic and trait-based community changes.


Assuntos
Organismos Aquáticos/classificação , Biodiversidade , Classificação/métodos , Clima , Ecossistema , Meio Ambiente , Mar do Norte , Fenótipo
12.
Mar Pollut Bull ; 145: 429-435, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590807

RESUMO

Refined baseline inventories of non-indigenous species (NIS) are set per European Union Member State (MS), in the context of the Marine Strategy Framework Directive (MSFD). The inventories are based on the initial assessment of the MSFD (2012) and the updated data of the European Alien Species Information Network, in collaboration with NIS experts appointed by the MSs. The analysis revealed that a large number of NIS was not reported from the initial assessments. Moreover, several NIS initially listed are currently considered as native in Europe or were proven to be historical misreportings. The refined baseline inventories constitute a milestone for the MSFD Descriptor 2 implementation, providing an improved basis for reporting new NIS introductions, facilitating the MSFD D2 assessment. In addition, the inventories can help MSs in the establishment of monitoring systems of targeted NIS, and foster cooperation on monitoring of NIS across or within shared marine subregions.


Assuntos
Organismos Aquáticos/classificação , Espécies Introduzidas/estatística & dados numéricos , Organismos Aquáticos/crescimento & desenvolvimento , Monitoramento Ambiental , Europa (Continente) , União Europeia , Biologia Marinha
13.
Protist ; 170(5): 125680, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31563792

RESUMO

Marine unarmored dinoflagellates in the family Kareniaceae are known to possess chloroplasts of haptophyte origin, which contain fucoxanthin and its derivatives as major carotenoids, and lack peridinin. In the present study, the first species with the peridinin-type chloroplast in this family, Gertia stigmatica gen. et sp. nov., is described on the basis of ultrastructure, photosynthetic pigment composition, and molecular phylogeny inferred from nucleus- and chloroplast-encoded genes. Cells of G. stigmatica were small and harboring a chloroplast with an eyespot and two pyrenoids. The apical structure complex was straight, similar to Karenia and Karlodinium. Under transmission electron microscopy, the chloroplast was surrounded by two membranes, and the eyespot was composed of a single layer of osmiophilic globules (eyespot type A); this was never previously reported from the Kareniaceae. High performance liquid chromatography demonstrated the chloroplast contains peridinin, and neither fucoxanthin nor 19'-acyloxyfucoxanthins was identified. A phylogeny based on nucleus-encoded rDNAs suggested a position of G. stigmatica in the Kareniaceae, but not clustered within the previously described genera, i.e., Karenia, Karlodinium and Takayama. A phylogeny of chloroplast-encoded psbA, psbC and psbD indicated the chloroplast is of peridinin-type typical of dinoflagellates, but the most related species remains unclear.


Assuntos
Organismos Aquáticos , Carotenoides , Cloroplastos , Dinoflagelados/classificação , Organismos Aquáticos/classificação , Organismos Aquáticos/citologia , Organismos Aquáticos/metabolismo , Carotenoides/metabolismo , Cloroplastos/classificação , Cloroplastos/metabolismo , Dinoflagelados/citologia , Dinoflagelados/metabolismo , Especificidade da Espécie
14.
Artigo em Inglês | MEDLINE | ID: mdl-31480868

RESUMO

Multivariate spatial patterns of 38 environmental variables (habitat metrics, metals, pyrethroids and sediment characteristics) and 14 benthic metrics were determined from over a decade of sampling in five California waterbodies. Canonical discriminant analyses produced very highly significant separations of the five watersheds based on environmental variables. The discriminant analyses based on benthic metrics also produced highly significant separations, although confidence ellipses were not quite as well separated as the environmental variables. Separation of creeks made ecological sense as Pleasant Grove Creek (PGC), which appeared to have greater habitat quality also had benthic metrics indicative of less stressed benthic communities, while the Santa Maria River watershed (SM) appeared to have lower habitat quality and more toxicants in the sediments also appeared to have benthic communities indicative of stress-tolerant taxa. The benthic community health of the other three creeks (Arcade Creek [ARC], Kirker Creek [KC] and Salinas Streams [SAL]) were considered intermediate in apparent stress between PGC and SM. Overall, benthic communities were somewhat more similar between creeks than were the environmental conditions. Benthic communities have greater overlap in characteristics than would be expected from environmental conditions, perhaps due to a greater resilience since they are generally dominated by tolerant benthic taxa.


Assuntos
Organismos Aquáticos/classificação , Monitoramento Ambiental , Rios/química , Poluentes Químicos da Água/análise , Animais , Organismos Aquáticos/efeitos dos fármacos , California , Ecossistema , Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Análise Multivariada , Poluentes Químicos da Água/toxicidade
15.
Mar Pollut Bull ; 149: 110560, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31542599

RESUMO

Disposal of mine tailings in marine shallow water ecosystems represents an environmental challenge, and the present paper reports results from a field study in Frænfjorden, Norway, which is subject to such disposal. Structural and functional responses of benthic infauna and epifauna were investigated along a gradient from heavy tailings deposition to reference conditions. The tailings clearly impacted the faunal composition, with lowered species number close to the outfall. Total abundance of infauna increased in the most impacted area due to dominance of opportunistic species, whereas the epifauna was reduced and represented by a few scattered specimens only. In the most impacted area functional responses included an increase in mobile carnivores/omnivores and species utilizing symbionts. Sessile and tube-living taxa, and deposit and suspension feeders decreased, probably due to smothering in combination with tailings-associated changes of the substrate. Functional diversity decreased for both infauna and epifauna, but less than the structural diversity.


Assuntos
Organismos Aquáticos/fisiologia , Ecossistema , Resíduos Industriais , Mineração , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/crescimento & desenvolvimento , Organismos Aquáticos/isolamento & purificação , Monitoramento Ambiental , Estuários , Sedimentos Geológicos/química , Noruega
16.
Nature ; 572(7771): 648-650, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31391584

RESUMO

More than three billion people rely on seafood for nutrition. However, fish are the predominant source of human exposure to methylmercury (MeHg), a potent neurotoxic substance. In the United States, 82% of population-wide exposure to MeHg is from the consumption of marine seafood and almost 40% is from fresh and canned tuna alone1. Around 80% of the inorganic mercury (Hg) that is emitted to the atmosphere from natural and human sources is deposited in the ocean2, where some is converted by microorganisms to MeHg. In predatory fish, environmental MeHg concentrations are amplified by a million times or more. Human exposure to MeHg has been associated with long-term neurocognitive deficits in children that persist into adulthood, with global costs to society that exceed US$20 billion3. The first global treaty on reductions in anthropogenic Hg emissions (the Minamata Convention on Mercury) entered into force in 2017. However, effects of ongoing changes in marine ecosystems on bioaccumulation of MeHg in marine predators that are frequently consumed by humans (for example, tuna, cod and swordfish) have not been considered when setting global policy targets. Here we use more than 30 years of data and ecosystem modelling to show that MeHg concentrations in Atlantic cod (Gadus morhua) increased by up to 23% between the 1970s and 2000s as a result of dietary shifts initiated by overfishing. Our model also predicts an estimated 56% increase in tissue MeHg concentrations in Atlantic bluefin tuna (Thunnus thynnus) due to increases in seawater temperature between a low point in 1969 and recent peak levels-which is consistent with 2017 observations. This estimated increase in tissue MeHg exceeds the modelled 22% reduction that was achieved in the late 1990s and 2000s as a result of decreased seawater MeHg concentrations. The recently reported plateau in global anthropogenic Hg emissions4 suggests that ocean warming and fisheries management programmes will be major drivers of future MeHg concentrations in marine predators.


Assuntos
Organismos Aquáticos/metabolismo , Mudança Climática , Exposição Ambiental/análise , Pesqueiros/provisão & distribução , Peixes/metabolismo , Cadeia Alimentar , Compostos de Metilmercúrio/análise , Comportamento Predatório , Animais , Organismos Aquáticos/química , Organismos Aquáticos/classificação , Dieta/veterinária , Cação (Peixe)/metabolismo , Peixes/classificação , Contaminação de Alimentos/análise , Gadus morhua/metabolismo , Humanos , Alimentos Marinhos/análise , Água do Mar/química , Poluentes Químicos da Água/análise
17.
Biotechnol Lett ; 41(10): 1187-1200, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31418101

RESUMO

OBJECTIVES: Bifunctional alginate lyase can efficiently saccharify alginate biomass and prepare functional oligosaccharides of alginate. RESULTS: A new BP-2 strain that produces alginate lyase was screened and identified from rotted Sargassum. A new alginate lyase, Alg17B, belonging to the polysaccharide lyase family 17, was isolated and purified from BP-2 fermentation broth by freeze-drying, dialysis, and ion exchange chromatography. The enzymatic properties of the purified lyase were investigated. The molecular weight of Alg17B was approximately 77 kDa, its optimum reaction temperature was 40-45 °C, and its optimum reaction pH was 7.5-8.0. The enzyme was relatively stable at pH 7.0-8.0, with a temperature range of 25-35 °C, and the specific activity of the purified enzyme reached 4036 U/mg. A low Na+ concentration stimulated Alg17B enzyme activity, but Ca2+, Zn2+, and other metal ions inhibited it. Substrate specificity analysis, thin-layer chromatography, and mass spectrometry showed that Alg17B is an alginate lyase that catalyses the hydrolysis of sodium alginate, polymannuronic acid (polyM) and polyguluronic acid to produce monosaccharides and low molecular weight oligosaccharides. Alg17B is also bifunctional, exhibiting both endolytic and exolytic activities toward alginate, and has a wide substrate utilization range with a preference for polyM. CONCLUSIONS: Alg17B can be used to saccharify the main carbohydrate, alginate, in the ethanolic production of brown algae fuel as well as in preparing and researching oligosaccharides.


Assuntos
Organismos Aquáticos/enzimologia , Gammaproteobacteria/enzimologia , Polissacarídeo-Liase/isolamento & purificação , Polissacarídeo-Liase/metabolismo , Sargassum/microbiologia , Alginatos/metabolismo , Ácido Algínico/metabolismo , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Organismos Aquáticos/isolamento & purificação , Ativadores de Enzimas/análise , Inibidores Enzimáticos/análise , Estabilidade Enzimática , Gammaproteobacteria/classificação , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Concentração de Íons de Hidrogênio , Hidrólise , Peso Molecular , Monossacarídeos/metabolismo , Oligossacarídeos/metabolismo , Polissacarídeo-Liase/química , Polissacarídeo-Liase/genética , Polissacarídeos Bacterianos/metabolismo , Especificidade por Substrato , Temperatura
18.
Mar Pollut Bull ; 146: 884-892, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426232

RESUMO

Human occupation of coastal areas promotes the establishment of non-native species but information on bioinvasions is usually biased toward the Northern Hemisphere. We assessed non-native species' importance in sessile communities at six marinas along the most urbanized area of the Southwestern Atlantic coastline. We found 67 species, of which 19 are exotic. The most frequent species was the exotic polychaete Branchiomma luctuosum, while the most abundant was the exotic bryozoan Schizoporella errata that monopolized the substrata in three marinas. Along with S. errata, the exotic polychaete Hydroides elegans and ascidian Styela plicata dominated space in the three remaining marinas, while native species were in general rare. We show that communities associated with artificial substrata along this Brazilian urbanized area are dominated by exotic species and that using abundance data along with species identity can improve our understanding of the importance of exotic species for the dynamics of biological communities.


Assuntos
Organismos Aquáticos/crescimento & desenvolvimento , Animais , Organismos Aquáticos/classificação , Oceano Atlântico , Biota , Brasil , Briozoários/classificação , Briozoários/crescimento & desenvolvimento , Ecossistema , Atividades Humanas , Humanos , Espécies Introduzidas , Poliquetos/classificação , Poliquetos/crescimento & desenvolvimento , Dinâmica Populacional , Urocordados/classificação , Urocordados/crescimento & desenvolvimento
19.
Artigo em Inglês | MEDLINE | ID: mdl-31426713

RESUMO

Comprehensive bioassessment multiple stressor field studies were conducted in five waterbodies in the Central Valley, San Francisco and Central Coast areas of California between 2006 and 2017. Samples were collected over multiple years in Pleasant Grove Creek (PGC - 8 years), Kirker Creek (KC - 2 years), Arcade Creek (ARC - 3 years), Salinas streams (SAL - 3 years) and the lower Santa Maria River watershed (SM - 3 years). In each watershed, metrics indicative of physical habitat quality and the relative health of benthic communities were collected, along with measurements of various potential toxicants in sediment (metals and pyrethroids), total organic carbon (TOC) and sediment grain size characteristics. For all waterbodies, pyrethroids have been reported at concentrations suspected to be toxic based on single-species laboratory toxicity tests. The data from all of these studies were assembled into a single data base which was analyzed by a series of univariate and multivariate statistical analyses. These analyses were designed to examine overall relationships between benthic community health and environmental quality conditions across the watersheds, as well as to address the following two key questions: (1) Which benthic metrics (response indicators) were the most important to relationships with environmental quality conditions and how do these metrics rank from most to least important? and (2) Which environmental variables (stressors) were the most important in terms of relationships to benthic metrics indicative of community health and how do the stressors rank from most to least important? Consensus ranking of 14 benthic metrics showed that stress tolerant (% Tolerant taxa, Tolerance value and Collectors/gatherers) and stress sensitive (EPT taxa and taxa richness) were the most important. The consensus ranking of 38 environmental variables from most to least important showed that habitat metrics, metals and grain size characteristics were most important for shaping benthic communities while pyrethroids were not reported to be an important stressor across the geographic scope of the watersheds.


Assuntos
Organismos Aquáticos/classificação , Organismos Aquáticos/efeitos dos fármacos , Monitoramento Ambiental , Rios/química , Poluentes Químicos da Água/toxicidade , Animais , California , Ecossistema , Biomarcadores Ambientais/efeitos dos fármacos , Sedimentos Geológicos/análise , Testes de Toxicidade , Poluentes Químicos da Água/análise
20.
Sci Total Environ ; 687: 752-758, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412478

RESUMO

Freshwater releases to wetlands degraded by excessive soil salinity in estuarine areas have been widely used to restore vegetation and maintain biodiversity of the wetland ecosystems. However, freshwater release also alters the physical and chemical properties of the water body, having a profound impact on the ecology of restored wetland ecosystems. In this study, physical and chemical parameters of water quality were compared between restored and non-restored tidal wetlands after 10 years of freshwater release in the Yellow River estuary. In addition, benthic invertebrates were used as bioindicators to reveal the effects of freshwater release on estuarine wetland ecology. The results showed that there was a significant difference in salinity between restored and non-restored wetlands (P < 0.05), which led to differences in the composition of benthic invertebrate communities (ANOSIM P < 0.001). The primary components of benthic invertebrate community were insects in restored wetlands, and in non-restored tidal wetlands the primary components were annelids, crustaceans, and gastropods. More long-term monitoring research of the impacts of freshwater introduction on degraded estuarine wetland ecosystems is needed to fully assess consequences.


Assuntos
Organismos Aquáticos/fisiologia , Biodiversidade , Estuários , Invertebrados/fisiologia , Áreas Alagadas , Animais , Organismos Aquáticos/classificação , Monitoramento Ambiental , Invertebrados/química , Rios/química
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