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1.
Environ Sci Technol ; 54(11): 6468-6485, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32364720

RESUMO

Thousands of halogenated natural products (HNPs) pervade the terrestrial and marine environment. HNPs are generated by biotic and abiotic processes and range in complexity from low molecular mass natural halocarbons (nHCs, mostly halomethanes and haloethanes) to compounds of higher molecular mass which often contain oxygen and/or nitrogen atoms in addition to halogens (hHNPs). nHCs have a key role in regulating tropospheric and stratospheric ozone, while some hHNPs bioaccumulate and have toxic properties similar those of anthropogenic-persistent organic pollutants (POPs). Both chemical classes have common sources: biosynthesis by marine bacteria, phytoplankton, macroalgae, and some invertebrate animals, and both may be similarly impacted by alteration of production and transport pathways in a changing climate. The nHCs scientific community is advanced in investigating sources, atmospheric and oceanic transport, and forecasting climate change impacts through modeling. By contrast, these activities are nascent or nonexistent for hHNPs. The goals of this paper are to (1) review production, sources, distribution, and transport pathways of nHCs and hHNPs through water and air, pointing out areas of commonality, (2) by analogy to nHCs, argue that climate change may alter these factors for hHNPs, and (3) suggest steps to improve linkage between nHCs and hHNPs science to better understand and predict climate change impacts.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32281226

RESUMO

BACKGROUND: People with intellectual disability (ID) have few role models for sexual expression and behaviour, and those who identify as LGBTQ experience dual marginalization. The aim of this study is to explore knowledge and attitudes concerning patients with both ID and norm-breaking sexuality and/or gender identity among healthcare professionals in habilitation centres. METHOD: Data were collected from four focus group interviews that included 19 healthcare professionals from child and adult teams at two Swedish habilitation centres. Data were analysed using thematic analysis. RESULTS: Three themes were identified as follows: heteronormative treatment in health care, barriers for inclusion and possibilities for inclusion. CONCLUSIONS: Norm-breaking sexuality and gender identity are still relatively invisible in habilitation centres. People with ID are still predominately desexualized and perceptions regarding their sexuality are lagging behind the rest of society. Conditions that allow for more LGBTQ-affirmative practice were described by the teams that have undergone LGBTQ training.

3.
Int J Cancer ; 146(4): 1125-1138, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31219615

RESUMO

Increased expression of GLI1, the main Hedgehog signalling pathway effector, is related to unfavourable prognosis and progressive disease of certain breast cancer subtypes. We used conditional transgenic mice induced to overexpress GLI1 in the mammary epithelium either alone or in combination with deletion of one Trp53 allele to address the role of elevated GLI1 expression in breast tumour initiation and progression. Induced GLI1 expression facilitates mammary gland tumour formation and this was further increased upon heterozygous deletion of Trp53. The GLI1-induced primary tumours were of different murine molecular subtypes, including Normal-likeEx , Class8Ex , Claudin-LowEx and Erbb2-likeEx . The gene expression profiles of some of the tumours correlated well with the PAM50 subtypes for human breast cancer. Whole-exome sequencing revealed somatic mutation profiles with only little overlap between the primary tumours. Orthotopically serially transplanted GLI1-induced tumours maintained the main morphological characteristics of the primary tumours for ≥10 generations. Independent of Trp53 status and molecular subtype, the serially transplanted GLI1-induced tumours were able to grow both in the absence of transgenic GLI1 expression and in the presence of the GLI1 inhibitor GANT61. These data suggest that elevated GLI1 expression has a determinant role in tumour initiation; however, additional genetic events are required for tumour progression.


Assuntos
Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Proteína GLI1 em Dedos de Zinco/genética , Animais , Feminino , Expressão Gênica , Heterogeneidade Genética , Humanos , Imuno-Histoquímica , Masculino , Neoplasias Mamárias Experimentais/metabolismo , Camundongos , Camundongos Transgênicos , Transplante de Neoplasias , Proteína GLI1 em Dedos de Zinco/biossíntese
4.
6.
Scand J Prim Health Care ; 37(4): 476-483, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31682152

RESUMO

Objective: Primary care staff faces a complex work environment including a heavy administrative work load and perceive some work tasks as illegitimate. This study aimed to elucidate associations between the perceived legitimacy of work tasks, the psychosocial work environment, and the utilization of work time among Swedish primary care staff.Design and setting: The study was designed as a multicenter study involving all staff categories, i.e. registered nurses, primary care physicians, care administrators, nurse assistants and allied professionals, at eleven primary care centers in Sweden.Subjects: Participants completed the Bern Illegitimate Tasks Scale and the Copenhagen Psychosocial Questionnaire. They also recorded time spent on all work tasks, day by day during two separate weeks.Main outcome measures and results: More than a quarter (27%) of primary care physicians perceived a high proportion of unnecessary work tasks. After adjusting for profession, age and gender, the perception of having to perform unreasonable work tasks was positively associated with experiencing role conflicts and with the proportion of organization-related administration and service work tasks.Conclusion: Across all staff groups, the perception of unreasonable work tasks was more pronounced among staff with a high proportion of non-patient related administration. Also, the perception of having to perform a large amount of illegitimate work tasks affected the psychosocial work environment negatively, which might influence staffs perception of their professional roles. These results illuminate the importance of decision makers to thoroughly consider the distribution and allocation of non-patient related work tasks among staff in primary care.Key pointsWe observed an interaction between perception of having a large proportion of illegitimate work tasks and impaired psychosocial work environment. • More than a quarter of the primary care physicians perceived a high proportion of unnecessary work tasks.• Across all staff groups, performing unreasonable work tasks was associated with an experience of having role conflicts.• Across all staff groups, a perception of performing unreasonable work tasks was associated with the proportion of non-patient related administrative work tasks.


Assuntos
Atitude do Pessoal de Saúde , Atenção Primária à Saúde/organização & administração , Carga de Trabalho/psicologia , Local de Trabalho/psicologia , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saúde do Trabalhador , Papel Profissional/psicologia , Suécia , Fatores de Tempo , Adulto Jovem
7.
Mar Environ Res ; 151: 104778, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31488340

RESUMO

The influence of nutrient availability and light conditions on phytoplankton size-structure, nutritional strategy and production was studied in a phosphorus-poor estuary in the northern Baltic Sea receiving humic-rich river water. The relative biomass of mixotrophic nanophytoplankton peaked in spring when heterotrophic bacterial production was high, while autotrophic microphytoplankton had their maximum in summer when primary production displayed highest values. Limiting substance (phosphorus) only showed small temporal variations, and the day light was at saturating levels all through the study period. We also investigated if the phytoplankton taxonomic richness influences the production. Structural equation modelling indicated that an increase of the taxonomic richness during the warm summer combined with slightly higher phosphorus concentration lead to increased resource use efficiency, which in turn caused higher phytoplankton biomass and primary production. Our results suggest that climate warming would lead to higher primary production in northerly shallow coastal areas, which are influenced by humic-rich river run-off from un-disturbed terrestrial systems.


Assuntos
Estuários , Nutrientes , Fitoplâncton , Biomassa , Rios , Água do Mar
8.
BMJ Open ; 9(5): e027847, 2019 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-31122995

RESUMO

INTRODUCTION: The provision of healthcare services is not dedicated to promoting maintenance of function and does not target frail older persons at high risk of the main causes of morbidity and mortality. The aim of this study is to evaluate the effects of a proactive medical and social intervention in comparison with conventional care on a group of persons aged 75 and older selected by statistical prediction. METHODS AND ANALYSIS: In a pragmatic multicentre primary care setting (n=1600), a prediction model to find elderly (75+) persons at high risk of complex medical care or hospitalisation is used, followed by proactive medical and social care, in comparison with usual care. The study started in April 2017 with a run-in period until December 2017, followed by a 2-year continued intervention phase that will continue until the end of December 2019. The intervention includes several tools (multiprofessional team for rehabilitation, social support, medical care home visits and telephone support). Primary outcome measures are healthcare cost, number of hospital care episodes, hospital care days and mortality. Secondary outcome measures are number of outpatient visits, cost of social care and informal care, number of prescribed drugs, health-related quality of life, cost-effectiveness, sense of security, functional status and ability. We also study the care of elderly persons in a broader sense, by covering the perspectives of the patients, the professional staff and the management, and on a political level, by using semistructured interviews, qualitative methods and a questionnaire. ETHICS AND DISSEMINATION: Approved by the regional ethical review board in Linköping (Dnr 2016/347-31). The results will be presented in scientific journals and scientific meetings during 2019-2022 and are planned to be used for the development of future care models. TRIAL REGISTRATION NUMBER: NCT03180606.

9.
Environ Sci Process Impacts ; 21(5): 881-892, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31032511

RESUMO

Marine macroalgae are used worldwide for human consumption, animal feed, cosmetics and agriculture. In addition to beneficial nutrients, macroalgae contain halogenated natural products (HNPs), some of which have toxic properties similar to those of well-known anthropogenic contaminants. Sixteen species of red, green and brown macroalgae were collected in 2017-2018 from coastal waters of the northern Baltic Sea, Sweden Atlantic and Norway Atlantic, and analyzed for bromoanisoles (BAs) and methoxylated bromodiphenyl ethers (MeO-BDEs). Target compounds were quantified by gas chromatography-low resolution mass spectrometry (GC-LRMS), with qualitative confirmation in selected species by GC-high resolution mass spectrometry (GC-HRMS). Quantified compounds were 2,4-diBA, 2,4,6-triBA, 2'-MeO-BDE68, 6-MeO-BDE47, and two tribromo-MeO-BDEs and one tetrabromo-MeO-BDE with unknown bromine substituent positions. Semiquantitative results for pentabromo-MeO-BDEs were also obtained for a few species by GC-HRMS. Three extraction methods were compared; soaking in methanol, soaking in methanol-dichloromethane, and blending with mixed solvents. Extraction yields of BAs did not differ significantly (p > 0.05) with the three methods and the two soaking methods gave equivalent yields of MeO-BDEs. Extraction efficiencies of MeO-BDEs were significantly lower using the blend method (p < 0.05). For reasons of simplicity and efficiency, the soaking methods are preferred. Concentrations varied by orders of magnitude among species: ∑2BAs 57 to 57 700 and ∑5MeO-BDEs < 10 to 476 pg g-1 wet weight (ww). Macroalgae standing out with ∑2BAs >1000 pg g-1 ww were Ascophyllum nodosum, Ceramium tenuicorne, Ceramium virgatum, Fucus radicans, Fucus serratus, Fucus vesiculosus, Saccharina latissima, Laminaria digitata, and Acrosiphonia/Spongomorpha sp. Species A. nodosum, C. tenuicorne, Chara virgata, F. radicans and F. vesiculosus (Sweden Atlantic only) had ∑5MeO-BDEs >100 pg g-1 ww. Profiles of individual compounds showed distinct differences among species and locations.


Assuntos
Anisóis/análise , Monitoramento Ambiental/métodos , Éteres Difenil Halogenados/análise , Hidrocarbonetos Bromados/análise , Alga Marinha/química , Poluentes Químicos da Água/análise , Animais , Cromatografia Gasosa-Espectrometria de Massas , Halogenação , Humanos , Noruega , Oceanos e Mares , Suécia
10.
Nutr Clin Pract ; 34(6): 887-898, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30644591

RESUMO

BACKGROUND: This study aimed to assess adherence to oral nutrition supplements (ONS) among hospital outpatients and to assess patient characteristics, experiences of ONS, and the characteristics of ONS prescriptions in clinical practice. METHODS: Hospital outpatients aged ≥18 years and prescribed ONS by a dietitian at a Swedish hospital were referred to the study from September 2016 to February 2017. Data were collected from structured telephone interviews, medical records, and a register of ONS delivered. Adherence to ONS was measured by dividing self-reported intake of ONS (frequency question and 24-hour recall question) by the amount prescribed and using the medication possession ratio (MPR). RESULTS: Of the 96 patients included (mean age 67 ± 13 years), 52% were male. The 2 most frequent medical diagnoses were malignancy and digestive system disease. Mean adherence to ONS was 93% measured by the frequency question, 87% measured by the 24-hour recall question, and 76% according to MPR. The majority of the patients (83%) were prescribed 1-3 bottles of ONS/day. The average number of flavors of ONS delivered was 4.2. Before prescription, 69% of the patients had been allowed to taste the ONS and 92% had chosen the flavors to be prescribed. Over 75% liked the taste of the ONS and considered them to be good for their health. CONCLUSIONS: Adherence to ONS was high in this population, which might be explained by the individual tailoring of ONS prescriptions by a dietitian, positive experiences of ONS, and the relatively young mean age of the participants.


Assuntos
Suplementos Nutricionais/estatística & dados numéricos , Adesão à Medicação/estatística & dados numéricos , Nutricionistas/estatística & dados numéricos , Pacientes Ambulatoriais/estatística & dados numéricos , Administração Oral , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Prescrições de Medicamentos/estatística & dados numéricos , Feminino , Hospitais Universitários/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Suécia/epidemiologia , Paladar , Adulto Jovem
12.
Front Microbiol ; 9: 2926, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30555447

RESUMO

Coastal ecosystems are highly dynamic and can be strongly influenced by climate change, anthropogenic activities (e.g., pollution), and a combination of the two pressures. As a result of climate change, the northern hemisphere is predicted to undergo an increased precipitation regime, leading in turn to higher terrestrial runoff and increased river inflow. This increased runoff will transfer terrestrial dissolved organic matter (tDOM) and anthropogenic contaminants to coastal waters. Such changes can directly influence the resident biology, particularly at the base of the food web, and can influence the partitioning of contaminants and thus their potential impact on the food web. Bacteria have been shown to respond to high tDOM concentration and organic pollutants loads, and could represent the entry of some pollutants into coastal food webs. We carried out a mesocosm experiment to determine the effects of: (1) increased tDOM concentration, (2) organic pollutant exposure, and (3) the combined effect of these two factors, on pelagic bacterial communities. This study showed significant responses in bacterial community composition under the three environmental perturbations tested. The addition of tDOM increased bacterial activity and diversity, while the addition of organic pollutants led to an overall reduction of these parameters, particularly under concurrent elevated tDOM concentration. Furthermore, we identified 33 bacterial taxa contributing to the significant differences observed in community composition, as well as 35 bacterial taxa which responded differently to extended exposure to organic pollutants. These findings point to the potential impact of organic pollutants under future climate change conditions on the basal coastal ecosystem, as well as to the potential utility of natural bacterial communities as efficient indicators of environmental disturbance.

13.
Sci Total Environ ; 634: 1352-1361, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29710635

RESUMO

We evaluated the dual role of DOM (i.e., as a source of inorganic nutrients and as an absorber of solar radiation) on a phytoplankton community of the western South Atlantic Ocean. Using a combination of microcosms and a cluster approach, we simulated the future conditions of some variables that are highly influenced by global change in the region. We increased nutrients (i.e., anthropogenic input) and dissolved organic matter (DOM), and we decreased the pH, to assess their combined impact on growth rates (µ), species composition/abundance and size structure, and photosynthesis (considering in this later also the effects of light quality i.e., with and without ultraviolet radiation). We simulated two Future conditions (Fut) where nutrients and pH were similarly manipulated, but in one the physical role of DOM (Futout) was assessed whereas in the other (Futin) the physico-chemical role was evaluated; these conditions were compared with a control (Present condition, Pres). The µ significantly increased in both Fut conditions as compared to the Pres, probably due to the nutrient addition and acidification in the former. The highest µ were observed in the Futout, due to the growth of nanoplanktonic flagellates and diatoms. Cells in the Futin were photosynthetically less efficient as compared to those of the Futout and Pres, but these physiological differences, also between samples with or without solar UVR observed at the beginning of the experiment, decreased with time hinting for an acclimation process. The knowledge of the relative importance of both roles of DOM is especially important for coastal areas that are expected to receive higher inputs and will be more acidified in the future.

14.
BMC Health Serv Res ; 18(1): 166, 2018 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-29514637

RESUMO

BACKGROUND: Over the past decades, reorganizations and structural changes in Swedish primary care have affected time utilization among health care professionals. Consequently, increases in administrative tasks have substantially reduced the time available for face-to-face consultations. This study examined how work-time was utilized and the association between work time utilization and the perceived psychosocial work environment in Swedish primary care settings. METHODS: This descriptive, multicentre, cross-sectional study was performed in 2014-2015. Data collection began with questionnaire. In the first section, respondents were asked to estimate how their workload was distributed between patients (direct and indirect patient work) and other work tasks. The questionnaire also comprised the Copenhagen Psychosocial Questionnaire, which assessed the psychosocial work environment. Next a time study was conducted where the participants reported their work-time based on three main categories: direct patient-related work, indirect patient-related work, and other work tasks. Each main category had a number of subcategories. The participants recorded the time spent (minutes) on each work task per hour, every day, for two separate weeks. Eleven primary care centres located in southeast Sweden participated. All professionals were asked to participate (n = 441), including registered nurses, primary care physicians, care administrators, nurse assistants, and allied professionals. Response rates were 75% and 79% for the questionnaires and the time study, respectively. RESULTS: All health professionals allocated between 30.9% - 37.2% of their work-time to each main category: direct patient work, indirect patient work, and other work. All professionals estimated a higher proportion of time spent in direct patient work than they reported in the time study. Physicians scored highest on the psychosocial scales of quantitative demands, stress, and role conflicts. Among allied professionals, the proportion of work-time spent on administrative tasks was associated with more role conflicts. Younger staff perceived more adverse working conditions than older staff. CONCLUSIONS: This study indicated that Swedish primary care staff spent a limited proportion of their work time directly with patients. PCPs seemed to perceive their work environment in negative terms to a greater extent than other staff members. This study showed that work task allocations influenced the perceived psychosocial work environment.


Assuntos
Atitude do Pessoal de Saúde , Pessoal de Saúde/psicologia , Atenção Primária à Saúde/organização & administração , Carga de Trabalho/estatística & dados numéricos , Local de Trabalho/psicologia , Adulto , Idoso , Estudos Transversais , Feminino , Pessoal de Saúde/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Médicos de Atenção Primária/psicologia , Médicos de Atenção Primária/estatística & dados numéricos , Inquéritos e Questionários , Suécia , Estudos de Tempo e Movimento , Adulto Jovem
15.
Glob Chang Biol ; 24(8): 3692-3714, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29543363

RESUMO

Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial-aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)-the messenger between terrestrial and lake ecosystems-with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change-driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice-out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans.


Assuntos
Mudança Climática , Cadeia Alimentar , Animais , Peixes , Lagos/química , Rios/química , Estações do Ano
16.
Int J Qual Stud Health Well-being ; 13(1): 1438697, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29464990

RESUMO

There is a demand for interventions aimed at adolescent girls with psychosomatic problems. In 2013, positive results were reported from a dance intervention programme addressing girls with internalizing problems. The research team behind the intervention immediately received requests from municipalities and county councils interested in using the intervention. From an implementation point of view it is unclear what made the intervention spread without an active plan. The aim of this study was to explore adopters' experiences about the diffusion and initiation of a public health intervention targeting adolescent girls with internalizing problems. Interviews were conducted with 12 people who were engaged in initiating the intervention in different settings. Data were analysed using conventional content analysis, yielding three categories: perceived appeal and trustworthiness, convenient information, and contextual factors. The results reflected that the participants found that there was a need for an intervention and found the dance intervention to be evidence based and not too complex to perform. Further, there was available information on the project which could easily be distributed to decision makers and others. When initiating the intervention, factors related to economy, possibility for collaboration and recruitment were of importance.


Assuntos
Atitude , Dança , Exercício Físico , Promoção da Saúde , Serviços de Saúde , Transtornos Somatoformes/terapia , Estresse Psicológico/terapia , Adolescente , Dança/psicologia , Difusão de Inovações , Exercício Físico/psicologia , Feminino , Humanos , Masculino , Pesquisa Qualitativa , Inquéritos e Questionários , Suécia
17.
Mar Environ Res ; 129: 236-244, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28645656

RESUMO

Climate change predictions indicate that coastal and estuarine environments will receive increased terrestrial runoff via increased river discharge. This discharge transports allochthonous material, containing bioavailable nutrients and light attenuating matter. Since light and nutrients are important drivers of basal production, their relative and absolute availability have important consequences for the base of the aquatic food web, with potential ramifications for higher trophic levels. Here, we investigated the effects of shifts in terrestrial organic matter and light availability on basal producers and their grazers. In twelve Baltic Sea mesocosms, we simulated the effects of increased river runoff alone and in combination. We manipulated light (clear/shade) and carbon (added/not added) in a fully factorial design, with three replicates. We assessed microzooplankton grazing preferences in each treatment to assess whether increased terrestrial organic matter input would: (1) decrease the phytoplankton to bacterial biomass ratio, (2) shift microzooplankton diet from phytoplankton to bacteria, and (3) affect microzooplankton biomass. We found that carbon addition, but not reduced light levels per se resulted in lower phytoplankton to bacteria biomass ratios. Microzooplankton generally showed a strong feeding preference for phytoplankton over bacteria, but, in carbon-amended mesocosms which favored bacteria, microzooplankton shifted their diet towards bacteria. Furthermore, low total prey availability corresponded with low microzooplankton biomass and the highest bacteria/phytoplankton ratio. Overall our results suggest that in shallow coastal waters, modified with allochthonous matter from river discharge, light attenuation may be inconsequential for the basal producer balance, whereas increased allochthonous carbon, especially if readily bioavailable, favors bacteria over phytoplankton. We conclude that climate change induced shifts at the base of the food web may alter energy mobilization to and the biomass of microzooplankton grazers.


Assuntos
Carbono/metabolismo , Ecossistema , Monitoramento Ambiental , Cadeia Alimentar , Bactérias , Biomassa , Mudança Climática , Eutrofização , Fitoplâncton/metabolismo , Rios
18.
Front Microbiol ; 8: 351, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28337180

RESUMO

Increased river loads are projected as one of the major consequences of climate change in the northern hemisphere, leading to elevated inputs of riverine dissolved organic matter (DOM) and inorganic nutrients to coastal ecosystems. The objective of this study was to investigate the effects of elevated DOM on a coastal pelagic food web from the coastal northern Baltic Sea, in a 32-day mesocosm experiment. In particular, the study addresses the response of bacterioplankton to differences in character and composition of supplied DOM. The supplied DOM differed in stoichiometry and quality and had pronounced effects on the recipient bacterioplankton, driving compositional changes in response to DOM type. The shifts in bacterioplankton community composition were especially driven by the proliferation of Bacteroidetes, Gemmatimonadetes, Planctomycetes, and Alpha- and Betaproteobacteria populations. The DOM additions stimulated protease activity and a release of inorganic nutrients, suggesting that DOM was actively processed. However, no difference between DOM types was detected in these functions despite different community compositions. Extensive release of re-mineralized carbon, nitrogen and phosphorus was associated with the bacterial processing, corresponding to 25-85% of the supplied DOM. The DOM additions had a negative effect on phytoplankton with decreased Chl a and biomass, particularly during the first half of the experiment. However, the accumulating nutrients likely stimulated phytoplankton biomass which was observed to increase towards the end of the experiment. This suggests that the nutrient access partially outweighed the negative effect of increased light attenuation by accumulating DOM. Taken together, our experimental data suggest that parts of the future elevated riverine DOM supply to the Baltic Sea will be efficiently mineralized by microbes. This will have consequences for bacterioplankton and phytoplankton community composition and function, and significantly affect nutrient biogeochemistry.

19.
Sci Adv ; 3(1): e1601239, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28138547

RESUMO

The input of mercury (Hg) to ecosystems is estimated to have increased two- to fivefold during the industrial era, and Hg accumulates in aquatic biota as neurotoxic methylmercury (MeHg). Escalating anthropogenic land use and climate change are expected to alter the input rates of terrestrial natural organic matter (NOM) and nutrients to aquatic ecosystems. For example, climate change has been projected to induce 10 to 50% runoff increases for large coastal regions globally. A major knowledge gap is the potential effects on MeHg exposure to biota following these ecosystem changes. We monitored the fate of five enriched Hg isotope tracers added to mesocosm scale estuarine model ecosystems subjected to varying loading rates of nutrients and terrestrial NOM. We demonstrate that increased terrestrial NOM input to the pelagic zone can enhance the MeHg bioaccumulation factor in zooplankton by a factor of 2 to 7 by inducing a shift in the pelagic food web from autotrophic to heterotrophic. The terrestrial NOM input also enhanced the retention of MeHg in the water column by up to a factor of 2, resulting in further increased MeHg exposure to pelagic biota. Using mercury mass balance calculations, we predict that MeHg concentration in zooplankton can increase by a factor of 3 to 6 in coastal areas following scenarios with 15 to 30% increased terrestrial runoff. The results demonstrate the importance of incorporating the impact of climate-induced changes in food web structure on MeHg bioaccumulation in future biogeochemical cycling models and risk assessments of Hg.


Assuntos
Biota , Cadeia Alimentar , Compostos de Metilmercúrio/metabolismo , Modelos Biológicos , Zooplâncton/crescimento & desenvolvimento , Animais
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