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1.
J Environ Manage ; 299: 113452, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34526276

RESUMO

Cadiz Bay is a shallow mesotidal lagoon with extensive populations of the seagrass Cymodocea nodosa at intertidal and shallow subtidal elevations. This work aims to understand the mechanisms behind the resilience of this species to gradual sea level rise by studying its acclimation capacity to depth along the shallow littoral, and therefore, to gradual variations in the light environment. To address this objective, these populations have been monitored seasonally over a 10 year period, representing the longest seasonal database available in the literature for this species. The monitoring included populations at 0.4, -0.08 and -0.5 m LAT. The results show that C. nodosa has a strong seasonality for demographic and shoot dynamic properties - with longer shoots and larger growth in summer (high temperature) than in winter (low temperature), but also some losses. Moreover, shoots have different leaf morphometry depending on depth, with small and dense shoots in the intertidal areas (0.4 m) and sparse large shoots in the subtidal ones (-0.08 and 0.5 m). These differences in morphometry and shoot dynamic properties, combined with the differences in shoot density, explain the lack of differences in meadow production balance (i.e. meadow growth - meadow losses) between the intertidal (0.4 m) and the deepest population (-0.5 m), supporting the long term resilience of Cymodocea nodosa in Cadiz Bay. This study contributes to the understanding of the mechanisms behind seagrass stability and resilience, which is particularly important towards predicting the effects of climate change on these key coastal ecosystems, and also highlights the value of continuous long-term monitoring efforts to evaluate seagrass trajectories.


Assuntos
Alismatales , Ecossistema , Aclimatação , Mudança Climática , Folhas de Planta
2.
J Appl Microbiol ; 127(1): 219-229, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30973185

RESUMO

AIM: To determine the protective capacity against Salmonella infection in mice of the cell-free fraction (postbiotic) of fermented milk, produced at laboratory and industrial level. METHODS AND RESULTS: The proteolytic activity (PA) of 5 commercial cultures and 11 autochthonous Lactobacillus strains was evaluated. The DSM-100H culture displayed the highest PA and it was selected for further studies. The capacity of the postbiotics produced by pH-controlled fermentation to stimulate the production of secretory IgA in faeces and to protect mice against Salmonella infection was evaluated. A significant increase in secretory IgA in faeces of mice fed 14 days the postbiotic obtained at the laboratory (F36) was detected compared to control animals. A significantly higher survival was observed in mice fed the F36 and the FiSD (industrial product) compared to controls. CONCLUSION: The postbiotics obtained showed immunomodulatory and protective capacity against Salmonella infection in mice. SIGNIFICANCE AND IMPACT OF THE STUDY: The pH-controlled milk fermentation by the proteolytic DSM-100H culture could be a suitable strategy to obtain a food ingredient to be added to a given food matrix, not adequate to host viable cells of probiotics, to confer it enhanced functionality and thus expand the functional food market.


Assuntos
Ração Animal/microbiologia , Produtos Fermentados do Leite/microbiologia , Alimento Funcional/microbiologia , Probióticos/metabolismo , Infecções por Salmonella/prevenção & controle , Animais , Imunoglobulina A Secretora/sangue , Lactobacillus/metabolismo , Camundongos , Proteólise
3.
Oecologia ; 182(2): 595-609, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27272209

RESUMO

Pollen limitation may be an important factor in accelerated decline of sparse or fragmented populations. Little is known whether hydrophilous plants (pollen transport by water) suffer from an Allee effect due to pollen limitation or not. Hydrophilous pollination is a typical trait of marine angiosperms or seagrasses. Although seagrass flowers usually have high pollen production, floral densities are highly variable. We evaluated pollen limitation for intertidal populations of the seagrass Zostera noltei in The Netherlands and found a significant positive relation between flowering spathe density and fruit-set, which was suboptimal at <1200 flowering spathes m(-2) (corresponding to <600 reproductive shoots m(-2)). A fragmented population had ≈35 % lower fruit-set at similar reproductive density than a continuous population. 75 % of all European populations studied over a large latitudinal gradient had flowering spathe densities below that required for optimal fruit-set, particularly in Southern countries. Literature review of the reproductive output of hydrophilous pollinated plants revealed that seed- or fruit-set of marine hydrophilous plants is generally low, as compared to hydrophilous freshwater and wind-pollinated plants. We conclude that pollen limitation as found in Z. noltei may be a common Allee effect for seagrasses, potentially accelerating decline and impairing recovery even after environmental conditions have improved substantially.


Assuntos
Pólen , Polinização , Flores , Magnoliopsida , Reprodução , Sementes
5.
J Dairy Sci ; 96(9): 5465-76, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23810598

RESUMO

In this work, we studied the growth, survival, and peptidolytic activity of Lactobacillus plantarum I91 in a hard-cheese model consisting of a sterile extract of Reggianito cheese. To assess the influence of the primary starter and initial proteolysis level on these parameters, we prepared the extracts with cheeses that were produced using 2 different starter strains of Lactobacillus helveticus 138 or 209 (Lh138 or Lh209) at 3 ripening times: 3, 90, and 180 d. The experimental extracts were inoculated with Lb. plantarum I91; the control extracts were not inoculated and the blank extracts were heat-treated to inactivate enzymes and were not inoculated. All extracts were incubated at 34°C for 21 d, and then the pH, microbiological counts, and proteolysis profiles were determined. The basal proteolysis profiles in the extracts of young cheeses made with either strain tested were similar, but many differences between the proteolysis profiles of the extracts of the Lh138 and Lh209 cheeses were found when riper cheeses were used. The pH values in the blank and control extracts did not change, and no microbial growth was detected. In contrast, the pH value in experimental extracts decreased, and this decrease was more pronounced in extracts obtained from either of the young cheeses and from the Lh209 cheese at any stage of ripening. Lactobacillus plantarum I91 grew up to 8 log during the first days of incubation in all of the extracts, but then the number of viable cells decreased, the extent of which depended on the starter strain and the age of the cheese used for the extract. The decrease in the counts of Lb. plantarum I91 was observed mainly in the extracts in which the pH had diminished the most. In addition, the extracts that best supported the viability of Lb. plantarum I91 during incubation had the highest free amino acids content. The effect of Lb. plantarum I91 on the proteolysis profile of the extracts was marginal. Significant changes in the content of free amino acids suggested that the catabolism of free amino acids by Lb. plantarum I91 prevailed in a weakly proteolyzed medium, whereas the release of amino acids due to peptidolysis overcame their catabolism in a medium with high levels of free amino acids. Lactobacillus plantarum I91 was able to use energy sources other than lactose to support its growth because equivalent numbers of cells were observed in extracts containing residual amounts of lactose and in lactose-depleted extracts. The contribution of Lb. plantarum I91 to hard-cooked cheese peptidolysis was negligible compared with that of the starter strain; however, its ability to transform amino acids is a promising feature of this strain.


Assuntos
Queijo/microbiologia , Lactobacillus plantarum/crescimento & desenvolvimento , Aminoácidos/análise , Carga Bacteriana , Queijo/análise , Tecnologia de Alimentos/métodos , Concentração de Íons de Hidrogênio , Lactobacillus plantarum/metabolismo , Proteólise , Fatores de Tempo
6.
Arch Soc Esp Oftalmol (Engl Ed) ; 98(5): 265-269, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37075840

RESUMO

OBJECTIVE: To apply artificial intelligence (AI) techniques, through deep learning algorithms, for the development and optimization of a system for predicting the age of a person based on a color retinography and to study a possible relationship between the evolution of retinopathy diabetes and premature ageing of the retina. METHODS: A convolutional network was trained to calculate the age of a person based on a retinography. Said training was carried out on a set of retinographies of patients with diabetes previously divided into three subsets (training, validation and test). The difference between the chronological age of the patient and the biological age of the retina was defined as the retinal age gap. RESULTS: A set of 98,400 images was used for the training phase, 1000 images for the validation phase and 13,544 for the test phase. The retinal gap of the patients without DR was 0.609 years and that of the patients with DR was 1905 years (p < 0.001), with the distribution by degree of DR being: mild DR: 1541 years, moderate DR: 3017 years, DR severe: 3117 years and proliferative DR: 8583 years. CONCLUSIONS: The retinal age gap shows a positive mean difference between diabetics with DR versus those without DR, and it increases progressively, according to the degree of DR. These results could indicate the existence of a relationship between the evolution of the disease and premature ageing of the retina.


Assuntos
Diabetes Mellitus , Retinopatia Diabética , Humanos , Retinopatia Diabética/diagnóstico por imagem , Inteligência Artificial , Retina/diagnóstico por imagem , Algoritmos , Biomarcadores
7.
Sci Total Environ ; 846: 157410, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-35850332

RESUMO

During the last decades many salt marshes worldwide have suffered important losses in their extent and associated ecosystem services. The salt marshes of San Vicente de la Barquera estuary (N Spain) are a clear example of this, with a drastic reduction in vegetation surface over the last 60 years. This paper provides insights into the main factors controlling salt marsh functioning in sheltered estuarine areas. Regional and local factors have been disaggregated to identify the main drivers controlling the functioning of the salt marsh to develop appropriate management measures according to the evolution of the system. These factors have been studied in their spatial context through detailed maps of change in vegetation cover combined with topographic data obtained from UAV and RTK-DGPS surveys. The results demonstrate that in this estuary the salt marsh area is declining following a fragmentation process. No clear pattern of vegetation loss/gain with elevation has been identified. However, the results point to increased hydrodynamic stress in the area, with stronger currents inside the estuary. This is probably the major factor responsible for the decline of the salt marshes in the San Vicente de la Barquera estuary. Furthermore, several human interventions during the 20th century (local drivers) have also probably contributed to a lower resilience against SLR (regional driver). This work demonstrates that both natural and human drivers of change need to be considered when characterizing the evolution of salt marshes, wherever efficient management strategies need to be designed.


Assuntos
Estuários , Áreas Alagadas , Ecossistema , Espanha
8.
Clin Microbiol Infect ; 13(11): 1077-82, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17727685

RESUMO

The time from the start of incubation to a positive reading of blood cultures (time-to-positivity; TTP) is related to the concentration of bacteria in blood. Information concerning the correlation of TTP with clinical parameters, and its usefulness as a prognostic factor in patients with Escherichia coli bacteraemia, is limited. To investigate the relationship of TTP to clinical parameters, 459 cases of monomicrobial E. coli bloodstream infections from a single institution between 1997 and 2005 were reviewed. All cases involved patients who were not undergoing antibiotic treatment at the time of blood sampling. The in-hospital mortality rate was 6.3%. Median TTP was significantly shorter for patients who died than for those who survived (9.7 h, inter-quartile range 7.85-11.05 h vs. 11.2 h, inter-quartile range 10.1-11.4 h; p <0.001). Patients with TTP in the lowest quartile were more likely to be female, to have a non-urinary tract or an unknown origin of bacteraemia, to have severe sepsis or shock, and to subsequently die. In a multivariable Cox regression model, the hazard ratio for death from any cause for patients with a short TTP was 3.13 (95% CI 1.28-7.64; p 0.01). TTP in patients with E. coli bacteraemia provides prognostic information beyond that provided by the presence of haematological illness, a Charlson score > or =3, a non-urinary tract origin of bacteraemia, and the presence of severe sepsis or shock.


Assuntos
Bacteriemia/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/crescimento & desenvolvimento , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/sangue , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
9.
Int Angiol ; 26(4): 378-84, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18091707

RESUMO

AIM: Clinical and capillaroscopic evaluation of an association of Ruscus aculeatus, hesperidin methylchalcone (HMC) and ascorbic acid in chronic venous insufficiency METHODS: A prospective, multicenter and open clinical study. Chronic venous insufficiency patients were studied using clinical, etiological, anatomical, physiological classification (CEAP) symptom scale. Symptomatology, CEAP scale, and baseline, 2-, 4-, 6- and 8-week skin capillaroscopy were assessed. Treatment consisted of two capsules per day of Ruscus aculeatus 150 mg/HMC 150 mg/ascorbic acid 100 mg during 8 weeks. RESULTS: A total of 124 patients were studied, 109 female (89.28%), with a mean age of 52.5 (33-80+9.8). Initial intense reports were 79% pain, 85% heaviness, 74% cramps, 82% edema, decreasing to 20%, 12%, 8% and 14%, respectively, within two weeks, and symptomatology being absent at the end of treatment. Capillaroscopy changes at treatment completion were: 98% to 20% inter-capillary fluid decrease; 80% to 20% efferent loop thickening; 5% to 2% peri-capillary bed, and 5% to 4% mega-capillaries. CONCLUSION: Severe symptom decrease started from the second week until there were no symptoms at the end of treatment. It is the first time morphologic changes were observed in chronic venous insufficiency through capillaroscopy following a pharmacological intervention. Capillary-level effect was proportional to symptom decrease. Improvement was seen from the second week of treatment.


Assuntos
Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Chalconas/uso terapêutico , Hesperidina/análogos & derivados , Fitoterapia , Extratos Vegetais/uso terapêutico , Ruscus , Insuficiência Venosa/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Feminino , Hesperidina/uso terapêutico , Humanos , Perna (Membro)/irrigação sanguínea , Masculino , Angioscopia Microscópica , Pessoa de Meia-Idade , Insuficiência Venosa/complicações , Insuficiência Venosa/patologia
10.
J Res Natl Inst Stand Technol ; 110(3): 145-8, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-27308111

RESUMO

The NPDGamma collaboration has completed the construction of a pulsed cold neutron beam line on flight path12 at the Los Alamos Neutron Science Center (LANSCE). We describe the new beam line and characteristics of the beam. We report results of the moderator brightness and the guide performance measurements. FP12 has the highest pulsed cold neutron intensity for nuclear physics in the world.

11.
Chest ; 88(1): 89-93, 1985 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-4006561

RESUMO

Characteristics and prognostic relevance of morning dip of peak expiratory flow rate (PEFR) were evaluated in stable asthmatic subjects. Among 246 outpatients monitored four times daily for two weeks, 38 (group A) showed a significant difference between morning reading of PEFR and each of the others; they were compared to 38 randomly selected patients (group B) not showing morning dip in PEFR. Less frequent seasonal course, extrinsic pathogenesis, and sensitization to mites characterized group A; starting airflow limitation was more severe in those with morning dip, but no significant difference between mean PEFR measured throughout two weeks was found. At 6 to 12 weeks, morning dip was not found in 19 of 38 subjects in group A and appeared in seven of 38 subjects in group B, with no clearcut relationship to treatment being evident. At 25 to 104 weeks, no significant difference between therapeutic requirements and the forced expiratory volume in one second was detected; therefore, unlike the short-term, morning dip is not a risk factor for worse long-term prognosis.


Assuntos
Asma/fisiopatologia , Ritmo Circadiano , Fluxo Expiratório Forçado , Pico do Fluxo Expiratório , Adulto , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico
12.
J Thorac Cardiovasc Surg ; 82(4): 569-75, 1981 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7278348

RESUMO

Thirteen years' experience with the surgical treatment of hydatid cystic disease of the lung is analyzed. An unselected series of 149 consecutive patients is reviewed. The preoperative diagnosis was exact in 98% of the cases, our conclusions being based primarily upon radiologic findings. The procedures used were puncture-aspiration with the trocar-suction cup in 139 cases, enucleation in four, wedge resection in two, segmentectomy in one, and lobectomy in three. In 19 cases, capitonnage of the residual cavity was performed: in the rest, partial resection of the pericystic membrane was performed, everting the cavity toward the pleura and using a high negative pressure vacuum through the thoracic drainage tubes. The early mortality was 1%. The persistence of a residual cavity was five times more frequent in those cases in which capitonnage was performed. The recurrence rate of the disease after an average follow-up of 37.5 months per patient was 0% in patients with an unruptured cyst and 9.3% in those in whom the cyst had ruptured prior to operation. As a whole, the percentage of morbidity and mortality in the short and long terms in this series is superior to those quoted in the literature, where other procedures were used.


Assuntos
Equinococose Pulmonar/cirurgia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Equinococose Pulmonar/diagnóstico , Feminino , Humanos , Masculino , Métodos , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Recidiva
13.
J Endod ; 24(3): 197-8, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9558587

RESUMO

The aim of this study was to evaluate post space preparation difficulties in canals filled with Ketac Endo and with Grossman's sealer. Sixty-three single-rooted teeth were prepared using a step-back technique and were divided into four groups: group 1--canals were irrigated with 25% tannic acid and filled with Ketac Endo and a single-cone technique; group 2--canals were irrigated with 1% sodium hypochlorite and fillings done as in the previous group; group 3--canals were irrigated with 25% tannic acid and filled with Ketac Endo and one gutta-percha cone previously adapted with chloroform; and group 4--canals were irrigated with 1% sodium hypochlorite and filled with Grossman's sealer and a lateral condensation technique. After 72 h, canals post space were prepared using Peeso drills. The time required was measured in seconds and analyzed by Tukey multiple comparison test (level 5%). Post space preparation time for groups 1 to 3 was longer than for group 4 and longer for group 1 than for groups 2 to 4.


Assuntos
Cimentos de Ionômeros de Vidro , Técnica para Retentor Intrarradicular , Materiais Restauradores do Canal Radicular , Adstringentes , Cimentos Dentários , Combinação de Medicamentos , Guta-Percha , Humanos , Taninos Hidrolisáveis , Polivinil , Preparo de Canal Radicular/métodos , Hipoclorito de Sódio , Fatores de Tempo , Óxido de Zinco
14.
Rev Esp Cardiol ; 48 Suppl 7: 46-50, 1995.
Artigo em Espanhol | MEDLINE | ID: mdl-8775816

RESUMO

The authors review the literature dealing with heart transplantation in combination with that of other extrathoracic solid organs. Heart-lung transplantation was not considered in this review as it is a well-defined procedure that does not strictly fit the concept of multiorgan transplantation. We present the experience of the first case of heart-liver transplantation involving organs from two different donors reported in the world medical literature. The recipient was a 9-year-old boy with type II homozygous familial hypercholesterolemia. Nine years later, the activity of the patient is normal, as are his liver and heart functions. Our series consists of fours cases of heart-kidney transplantation in patients who were undergoing periodic hemodialysis to treat glomeruloangiosclerosis and presented concomitant end-stage heart disease. On two occasions, both heart and kidney were transplanted during the same surgical procedure with organs from a single donor. The first to be performed was heart transplantation, and the kidney transplantation procedure was undertaken once hemodynamic stability was achieved. The remaining two patients had undergone kidney transplantation two and three years prior to heart transplantation. All the patients are alive, with NYHA class I, and present good ventricular and kidney function. The mean follow-up period is 5 years.


Assuntos
Transplante de Órgãos , Adulto , Criança , Transplante de Coração , Humanos , Transplante de Rim , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Transplante de Órgãos/métodos , Espanha
15.
Rev Esp Cardiol ; 51 Suppl 3: 44-50, 1998.
Artigo em Espanhol | MEDLINE | ID: mdl-9717402

RESUMO

Hospital deaths from acute myocardial infarction are the consequence of cardiac arrhythmias and cardiac pump failure. However, for a limited period of time following the interruption of the coronary blood flow, a significant portion of the myocardium remains in a situation of "reversibility", which means that if the coronary flow is reestablished, the infarcted area is reduced. Pos-acute myocardial infarction reperfusion methods include thrombolytic therapy, percutaneous transluminal coronary angioplasty and surgical revascularization of the myocardium. The indications for the latter method, which is employed when procedures such as thrombolysis and percutaneous transluminal coronary angioplasty have failed, are analyzed and the results are discussed in terms of the time elapsed since the onset of acute myocardial infarction, ejection fraction, the number of vessels involved, the type of infarction and the concurrence of cardiogenic shock. The advisability of adopting different strategies and priorities for surgical revascularization in certain situations is indicated.


Assuntos
Infarto do Miocárdio/cirurgia , Revascularização Miocárdica , Angioplastia Coronária com Balão , Emergências , Humanos , Reperfusão Miocárdica , Choque Cardiogênico/cirurgia , Terapia Trombolítica , Fatores de Tempo
16.
Rev Esp Cardiol ; 51(8): 684-6, 1998 Aug.
Artigo em Espanhol | MEDLINE | ID: mdl-9780786

RESUMO

The use of endoscopic technology is gaining more and more popularity within cardiac surgery. We present a case employing endoscopic instruments in the resection of the interventricular septum in a patient with hypertrophic cardiomyopathy unresponsive to medical treatment. Advantages of this technique are discussed.


Assuntos
Cardiomiopatia Hipertrófica/cirurgia , Endoscopia , Cardiomiopatia Hipertrófica/diagnóstico , Ecocardiografia Transesofagiana , Feminino , Humanos , Pessoa de Meia-Idade , Gravação de Videoteipe
17.
Arch Bronconeumol ; 34(9): 417-20, 1998 Oct.
Artigo em Espanhol | MEDLINE | ID: mdl-9842452

RESUMO

The standard, most widely applied way of preserving a lung for transplantation is infusion through the pulmonary artery (PA) of a pulmonaryplegic solution. In this prospective study, we analyzed the initial function of the pulmonary and cardiac graft after biphasic infusion of a solution introduced retrograde through the left auricle and antegrade through the PA. Twenty-six heart and lung grafts (9 unilateral and 17 bilateral) were preserved by cardioplegia and pulmonaryplegia (biphasic) between January 1996 and March 1997. Indicators of graft viability recorded were the ratio of arterial oxygen pressure (PaO2) to inspired fraction (FiO2), mean systemic pressure (MSP), mean pulmonary artery pressure (MPAP) cardiac output, pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR). The variables were recorded upon arrival of the grafts in the intensive care unit and in the first 24 h. Morbidity and mortality after heart transplants were recorded throughout a follow-up period of one month. After transplantation, most patients had a oxygenation coefficient (PaO2/FiO2) greater than 252 mmHg in the first 48 h. Hemodynamic parameters were also kept within normal ranges immediately after surgery and 24 h later. Mean ischemic time was 245 min for unilateral transplants, 215 for the first lung in double lung transplants, and 300 min for the second lung. In the early postoperative period, 3 patients suffered lung graft dysfunction, which was treated satisfactorily with nitric oxide (NO). No heart transplant patient suffered primary heart failure or left ventricular dilatation. We conclude that biphasic pulmonary preservation achieves satisfactory initial functional viability of the graft. Heart grafts removed simultaneously functioned successfully in the transplanted patient without additional pharmacological or mechanical support.


Assuntos
Transplante de Pulmão/métodos , Preservação de Órgãos , Artéria Pulmonar , Reperfusão/métodos , Adolescente , Adulto , Feminino , Transplante de Coração , Transplante de Coração-Pulmão , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
18.
Mar Pollut Bull ; 64(11): 2471-9, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22921898

RESUMO

An in-depth knowledge of solutes advection and turbulent diffusion is crucial to estimate dispersion area and retention time (t(R)) of pollutants within seagrass habitats. However, there is little knowledge on the influence of seagrass habitat fragmentation on such mechanisms. A set of dye tracer experiments and acoustic Doppler velocimeter measurements (ADV) were conducted. Solute transport conditions were compared in between fragmented (FM) vs homogeneous (HM) intertidal meadows, and in vertical gradients (canopy vs overlaying flow). Results showed the highest horizontal diffusion coefficient (K(y), c.a. 10(-3)m(2)s(-1)) on FM and at the canopy-water column interface, whereas t(R) (2.6-5.6 min) was not affected by fragmentation. It suggests that (1) FM are more vulnerable to pollution events in terms of dispersion area and (2) at low tide, advection rather than turbulent diffusion determines t(R). Furthermore, Taylor's theorem is revealed as a powerful tool to analyze vertical gradients on K(y) within seagrass canopies.


Assuntos
Ecossistema , Monitoramento Ambiental , Poluentes da Água/análise , Zosteraceae , Sedimentos Geológicos/análise , Modelos Químicos , Movimentos da Água , Poluição da Água/estatística & dados numéricos
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