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177 results on '"Simon, M.F."'

4. Magnetic resonance imaging detects onset and association with lung disease severity of bronchial artery dilatation in cystic fibrosis

Author

Patricia Leutz-Schmidt, Daiva-Elzbieta Optazaite, Olaf Sommerburg, Monika Eichinger, Sabine Wege, Eva Steinke, Simon Y. Graeber, Michael U. Puderbach, Jens-Peter Schenk, Abdulsattar Alrajab, Simon M.F. Triphan, Hans-Ulrich Kauczor, Mirjam Stahl, Marcus A. Mall, and Mark O. Wielpütz

Subjects
Medicine
Abstract

Background Bronchial artery dilatation (BAD) is associated with haemoptysis in advanced cystic fibrosis (CF) lung disease. Our aim was to evaluate BAD onset and its association with disease severity by magnetic resonance imaging (MRI). Methods 188 CF patients (mean±sd age 13.8±10.6 years, range 1.1–55.2 years) underwent annual chest MRI (median three exams, range one to six exams), contributing a total of 485 MRI exams including perfusion MRI. Presence of BAD was evaluated by two radiologists in consensus. Disease severity was assessed using the validated MRI scoring system and spirometry (forced expiratory volume in 1 s (FEV1) % pred). Results MRI demonstrated BAD in 71 (37.8%) CF patients consistently from the first available exam and a further 10 (5.3%) patients first developed BAD during surveillance. Mean MRI global score in patients with BAD was 24.5±8.3 compared with 11.8±7.0 in patients without BAD (p

Published
2023
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6. Magnetic Resonance Imaging of Lung Perfusion.

Author

Triphan, Simon M.F., Bauman, Grzegorz, Konietzke, Philip, Konietzke, Marilisa, and Wielpütz, Mark O.

Subjects
MAGNETIC resonance angiography, CHRONIC obstructive pulmonary disease, PULMONARY hypertension, PULMONARY artery diseases, PHYSIOLOGY, MAGNETIC resonance imaging
Abstract

"Lung perfusion" in the context of imaging conventionally refers to the delivery of blood to the pulmonary capillary bed through the pulmonary arteries originating from the right ventricle required for oxygenation. The most important physiological mechanism in the context of imaging is the so‐called hypoxic pulmonary vasoconstriction (HPV, also known as "Euler‐Liljestrand‐Reflex"), which couples lung perfusion to lung ventilation. In obstructive airway diseases such as asthma, chronic‐obstructive pulmonary disease (COPD), cystic fibrosis (CF), and asthma, HPV downregulates pulmonary perfusion in order to redistribute blood flow to functional lung areas in order to conserve optimal oxygenation. Imaging of lung perfusion can be seen as a reflection of lung ventilation in obstructive airway diseases. Other conditions that primarily affect lung perfusion are pulmonary vascular diseases, pulmonary hypertension, or (chronic) pulmonary embolism, which also lead to inhomogeneity in pulmonary capillary blood distribution. Several magnetic resonance imaging (MRI) techniques either dependent on exogenous contrast materials, exploiting periodical lung signal variations with cardiac action, or relying on intrinsic lung voxel attributes have been demonstrated to visualize lung perfusion. Additional post‐processing may add temporal information and provide quantitative information related to blood flow. The most widely used and robust technique, dynamic‐contrast enhanced MRI, is available in clinical routine assessment of COPD, CF, and pulmonary vascular disease. Non‐contrast techniques are important research tools currently requiring clinical validation and cross‐correlation in the absence of a viable standard of reference. First data on many of these techniques in the context of observational studies assessing therapy effects have just become available. Level of Evidence: 5 Technical Efficacy: Stage 5 [ABSTRACT FROM AUTHOR]

Published
2024
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7. Magnetic resonance imaging detects improvements of pulmonary and paranasal sinus abnormalities in response to elexacaftor/tezacaftor/ivacaftor therapy in adults with cystic fibrosis

Author

Lena Wucherpfennig, Simon M.F. Triphan, Sabine Wege, Hans-Ulrich Kauczor, Claus P. Heussel, Niclas Schmitt, Felix Wuennemann, Victoria L. Mayer, Olaf Sommerburg, Marcus A. Mall, Monika Eichinger, and Mark O. Wielpütz

Subjects
Adult, Pulmonary and Respiratory Medicine, Young Adult, Cystic Fibrosis, Mutation, Pediatrics, Perinatology and Child Health, Humans, Cystic Fibrosis Transmembrane Conductance Regulator, Benzodioxoles, Aminophenols, Lung, Magnetic Resonance Imaging
Abstract

Therapy with Elexacaftor/Tezacaftor/Ivacaftor (ETI) was recently approved for adult cystic fibrosis (CF) patients with at least one F508del mutation. However, its effects on structural and functional lung abnormalities and chronic rhinosinusitis have not been studied by imaging.19 adults with CF (mean age 31±9y, range 19-55y) underwent standardized chest magnetic resonance imaging (MRI), and nine also same-session sinonasal MRI, before (MRI1) and after (MRI2) at least one month (mean duration 5 ± 3mon) on ETI. 24 control CF patients (30±7y, range 20-44y) without ETI underwent longitudinal chest MRI, and eleven also sinonasal MRI, twice (mean interval 40±15mon). MRI was assessed using the validated chest MRI score and chronic rhinosinusitis (CRS)-MRI score. Forced expiratory volume in 1 s percent predicted (FEV1%) was measured in all patients.In controls, the chest MRI global score and CRS-MRI sum score were stable from MRI1 to MRI2. In patients under ETI, the chest MRI global score improved (-11.4 ± 4.6, P0.001), mainly due to reduction of bronchiectasis/wall thickening and mucus plugging subscores (-3.3 ± 2.2 and -5.2 ± 1.5, P0.001, respectively). The improvement in chest MRI score correlated well with improved FEV1% (r=-0.703, P0.001). The CRS-MRI sum score also improved in patients under ETI (-6.9 ± 3.0, P0.001), mainly due to a reduction of mucopyoceles in the maxillary and ethmoid sinus (-50% and -39%, P0.05, respectively).MRI detects improvements of chest MRI and CRS-MRI scores in adult CF patients who first received ETI, demonstrating reversibility of structural lung and paranasal sinus abnormalities in patients with established disease.

Published
2022
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11. Local hydrological conditions influence tree diversity and composition across the Amazon basin

Author

Marca-Zevallos, M.J., Moulatlet, G.M., Sousa, T.R., Schietti, J., Coelho, L.D.S., Ramos, J.F., Lima Filho, D.D.A., Amaral, I.L., de Almeida Matos, F.D., Rincón, L.M., Cardenas Revilla, J.D., Pansonato, M.P., Gribel, R., Barbosa, E.M., Miranda, I.P.D.A., Bonates, L.C.D.M., Guevara, J.E., Salomão, R.P., Ferreira, L.V., Dantas do Amaral, D., Pitman, N.C.A., Vriesendorp, C., Baker, T.R., Brienen, R., Carim, M.D.J.V., Guimarães, J.R.D.S., Núñez Vargas, P., Huamantupa-Chuquimaco, I., Laurance, W.F., Laurance, S.G.W., Andrade, A., Camargo, J.L., Monteagudo Mendoza, A., Vasquez, R., Valenzuela Gamarra, L., Mogollón, H.F., Marimon-Junior, B.H., Marimon, B.S., Killeen, T.J., Farias, E.D.S., Neill, D., de Medeiros, M.B., Simon, M.F., Terborgh, J., Carlos Montero, J., Licona, J.C., Mostacedo, B., García-Villacorta, R., Araujo-Murakami, A., Arroyo, L., Villarroel, D., Dávila, N., Coelho de Souza, F., Carvalho, F.A., Comiskey, J.A., Alonso, A., Dallmeier, F., Oliveira, A.A., Castilho, C.V., Lloyd, J., Feldpausch, T.R., Ríos Paredes, M., Castaño Arboleda, N., Cárdenas López, D., Aymard Corredor, G.A., Di Fiore, A., Rudas, A., Prieto, A., Barbosa, F.R., Noronha, J.C., Rodrigues, D.D.J., Carpanedo, R.D.S.á., Honorio Coronado, E.N., Peres, C.A., Milliken, W., Fuentes, A., Tello, J.S., Cerón, C., Klitgaard, B., Tirado, M., Sierra, R., Young, K.R., Rivas-Torres, G.F., Stevenson, P.R., Cano, A., Wang, O., Baider, C., Barlow, J., Ferreira, J., Berenguer, E., Stropp, J., Balslev, H., Ahuite Reategui, M.A., Mesones, I., Valderrama Sandoval, E.H., Gonzales, T., Pansini, S., Reis, N.F.C., Sampaio, A.F., Vos, V.A., Palacios Cuenca, W., Manzatto, A.G., Farfan-Rios, W., Silman, M.R., Garcia-Cabrera, K., von Hildebrand, P., Guedes, M.C., Costa, J.B.P., Phillips, J.F., Vela, C.I.A., de Toledo, J.J., Pauletto, D., Valverde, F.C., Umaña, M.N., Phillips, O.L., Magnusson, W.E., ter Steege, H., Costa, F.R.C., Marca-Zevallos, M.J., Moulatlet, G.M., Sousa, T.R., Schietti, J., Coelho, L.D.S., Ramos, J.F., Lima Filho, D.D.A., Amaral, I.L., de Almeida Matos, F.D., Rincón, L.M., Cardenas Revilla, J.D., Pansonato, M.P., Gribel, R., Barbosa, E.M., Miranda, I.P.D.A., Bonates, L.C.D.M., Guevara, J.E., Salomão, R.P., Ferreira, L.V., Dantas do Amaral, D., Pitman, N.C.A., Vriesendorp, C., Baker, T.R., Brienen, R., Carim, M.D.J.V., Guimarães, J.R.D.S., Núñez Vargas, P., Huamantupa-Chuquimaco, I., Laurance, W.F., Laurance, S.G.W., Andrade, A., Camargo, J.L., Monteagudo Mendoza, A., Vasquez, R., Valenzuela Gamarra, L., Mogollón, H.F., Marimon-Junior, B.H., Marimon, B.S., Killeen, T.J., Farias, E.D.S., Neill, D., de Medeiros, M.B., Simon, M.F., Terborgh, J., Carlos Montero, J., Licona, J.C., Mostacedo, B., García-Villacorta, R., Araujo-Murakami, A., Arroyo, L., Villarroel, D., Dávila, N., Coelho de Souza, F., Carvalho, F.A., Comiskey, J.A., Alonso, A., Dallmeier, F., Oliveira, A.A., Castilho, C.V., Lloyd, J., Feldpausch, T.R., Ríos Paredes, M., Castaño Arboleda, N., Cárdenas López, D., Aymard Corredor, G.A., Di Fiore, A., Rudas, A., Prieto, A., Barbosa, F.R., Noronha, J.C., Rodrigues, D.D.J., Carpanedo, R.D.S.á., Honorio Coronado, E.N., Peres, C.A., Milliken, W., Fuentes, A., Tello, J.S., Cerón, C., Klitgaard, B., Tirado, M., Sierra, R., Young, K.R., Rivas-Torres, G.F., Stevenson, P.R., Cano, A., Wang, O., Baider, C., Barlow, J., Ferreira, J., Berenguer, E., Stropp, J., Balslev, H., Ahuite Reategui, M.A., Mesones, I., Valderrama Sandoval, E.H., Gonzales, T., Pansini, S., Reis, N.F.C., Sampaio, A.F., Vos, V.A., Palacios Cuenca, W., Manzatto, A.G., Farfan-Rios, W., Silman, M.R., Garcia-Cabrera, K., von Hildebrand, P., Guedes, M.C., Costa, J.B.P., Phillips, J.F., Vela, C.I.A., de Toledo, J.J., Pauletto, D., Valverde, F.C., Umaña, M.N., Phillips, O.L., Magnusson, W.E., ter Steege, H., and Costa, F.R.C.

Abstract

Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures.

Published
2022

16. Biased-corrected richness estimates for the Amazonian tree flora

Author

ter Steege, H., Prado, P.I., Lima, R.A.F., Pos, E., de Souza Coelho, L., de Andrade Lima Filho, D., Salomão, R.P., Amaral, I.L., de Almeida Matos, F.D., Castilho, C.V., Phillips, O.L., Guevara, J.E., de Jesus Veiga Carim, M., Cárdenas López, D., Magnusson, W.E., Wittmann, F., Martins, M.P., Sabatier, D., Irume, M.V., da Silva Guimarães, J.R., Molino, J.-F., Bánki, O.S., Piedade, M.T.F., Pitman, N.C.A., Ramos, J.F., Monteagudo Mendoza, A., Venticinque, E.M., Luize, B.G., Núñez Vargas, P., Silva, T.S.F., de Leão Novo, E.M.M., Reis, N.F.C., Terborgh, J., Manzatto, A.G., Casula, K.R., Honorio Coronado, E.N., Montero, J.C., Duque, A., Costa, F.R.C., Castaño Arboleda, N., Schöngart, J., Zartman, C.E., Killeen, T.J., Marimon, B.S., Marimon-Junior, B.H., Vasquez, R., Mostacedo, B., Demarchi, L.O., Feldpausch, T.R., Engel, J., Petronelli, P., Baraloto, C., Assis, R.L., Castellanos, H., Simon, M.F., de Medeiros, M.B., Quaresma, A., Laurance, S.G.W., Rincón, L.M., Andrade, A., Sousa, T.R., Camargo, J.L., Schietti, J., Laurance, W.F., de Queiroz, H.L., Nascimento, H.E.M., Lopes, M.A., de Sousa Farias, E., Magalhães, J.L.L., Brienen, R., Aymard C, G.A., Revilla, J.D.C., Vieira, I.C.G., Cintra, B.B.L., Stevenson, P.R., Feitosa, Y.O., Duivenvoorden, J.F., Mogollón, H.F., Araujo-Murakami, A., Ferreira, L.V., Lozada, J.R., Comiskey, J.A., de Toledo, J.J., Damasco, G., Dávila, N., Lopes, A., García-Villacorta, R., Draper, F., Vicentini, A., Cornejo Valverde, F., Lloyd, J., Gomes, V.H.F., Neill, D., Alonso, A., Dallmeier, F., de Souza, F.C., Gribel, R., Arroyo, L., Carvalho, F.A., de Aguiar, D.P.P., do Amaral, D.D., Pansonato, M.P., Feeley, K.J., Berenguer, E., Fine, P.V.A., Guedes, M.C., Barlow, J., Ferreira, J., Villa, B., Peñuela Mora, M.C., Jimenez, E.M., Licona, J.C., Cerón, C., Thomas, R., Maas, P., Silveira, M., Henkel, T.W., Stropp, J., Paredes, M.R., Dexter, K.G., Daly, D., Baker, T.R., Huamantupa-Chuquimaco, I., Milliken, W., Pennington, T., Tello, J.S., Pena, J.L.M., Peres, C.A., Klitgaard, B., Fuentes, A., Silman, M.R., Di Fiore, A., von Hildebrand, P., Chave, J., van Andel, T.R., Hilário, R.R., Phillips, J.F., Rivas-Torres, G., Noronha, J.C., Prieto, A., Gonzales, T., de Sá Carpanedo, R., Gonzales, G.P.G., Gómez, R.Z., de Jesus Rodrigues, D., Zent, E.L., Ruschel, A.R., Vos, V.A., Fonty, É., Junqueira, A.B., Doza, H.P.D., Hoffman, B., Zent, S., Barbosa, E.M., Malhi, Y., de Matos Bonates, L.C., de Andrade Miranda, I.P., Silva, N., Barbosa, F.R., Vela, C.I.A., Pinto, L.F.M., Rudas, A., Albuquerque, B.W., Umaña, M.N., Carrero Márquez, Y.A., van der Heijden, G., Young, K.R., Tirado, M., Correa, D.F., Sierra, R., Costa, J.B.P., Rocha, M., Vilanova Torre, E., Wang, O., Oliveira, A.A., Kalamandeen, M., Vriesendorp, C., Ramirez-Angulo, H., Holmgren, M., Nascimento, M.T., Galbraith, D., Flores, B.M., Scudeller, V.V., Cano, A., Ahuite Reategui, M.A., Mesones, I., Baider, C., Mendoza, C., Zagt, R., Urrego Giraldo, L.E., Ferreira, C., Villarroel, D., Linares-Palomino, R., Farfan-Rios, W., Casas, L.F., Cárdenas, S., Balslev, H., Torres-Lezama, A., Alexiades, M.N., Garcia-Cabrera, K., Valenzuela Gamarra, L., Valderrama Sandoval, E.H., Ramirez Arevalo, F., Hernandez, L., Sampaio, A.F., Pansini, S., Palacios Cuenca, W., de Oliveira, E.A., Pauletto, D., Levesley, A., Melgaço, K., Pickavance, G., ter Steege, H., Prado, P.I., Lima, R.A.F., Pos, E., de Souza Coelho, L., de Andrade Lima Filho, D., Salomão, R.P., Amaral, I.L., de Almeida Matos, F.D., Castilho, C.V., Phillips, O.L., Guevara, J.E., de Jesus Veiga Carim, M., Cárdenas López, D., Magnusson, W.E., Wittmann, F., Martins, M.P., Sabatier, D., Irume, M.V., da Silva Guimarães, J.R., Molino, J.-F., Bánki, O.S., Piedade, M.T.F., Pitman, N.C.A., Ramos, J.F., Monteagudo Mendoza, A., Venticinque, E.M., Luize, B.G., Núñez Vargas, P., Silva, T.S.F., de Leão Novo, E.M.M., Reis, N.F.C., Terborgh, J., Manzatto, A.G., Casula, K.R., Honorio Coronado, E.N., Montero, J.C., Duque, A., Costa, F.R.C., Castaño Arboleda, N., Schöngart, J., Zartman, C.E., Killeen, T.J., Marimon, B.S., Marimon-Junior, B.H., Vasquez, R., Mostacedo, B., Demarchi, L.O., Feldpausch, T.R., Engel, J., Petronelli, P., Baraloto, C., Assis, R.L., Castellanos, H., Simon, M.F., de Medeiros, M.B., Quaresma, A., Laurance, S.G.W., Rincón, L.M., Andrade, A., Sousa, T.R., Camargo, J.L., Schietti, J., Laurance, W.F., de Queiroz, H.L., Nascimento, H.E.M., Lopes, M.A., de Sousa Farias, E., Magalhães, J.L.L., Brienen, R., Aymard C, G.A., Revilla, J.D.C., Vieira, I.C.G., Cintra, B.B.L., Stevenson, P.R., Feitosa, Y.O., Duivenvoorden, J.F., Mogollón, H.F., Araujo-Murakami, A., Ferreira, L.V., Lozada, J.R., Comiskey, J.A., de Toledo, J.J., Damasco, G., Dávila, N., Lopes, A., García-Villacorta, R., Draper, F., Vicentini, A., Cornejo Valverde, F., Lloyd, J., Gomes, V.H.F., Neill, D., Alonso, A., Dallmeier, F., de Souza, F.C., Gribel, R., Arroyo, L., Carvalho, F.A., de Aguiar, D.P.P., do Amaral, D.D., Pansonato, M.P., Feeley, K.J., Berenguer, E., Fine, P.V.A., Guedes, M.C., Barlow, J., Ferreira, J., Villa, B., Peñuela Mora, M.C., Jimenez, E.M., Licona, J.C., Cerón, C., Thomas, R., Maas, P., Silveira, M., Henkel, T.W., Stropp, J., Paredes, M.R., Dexter, K.G., Daly, D., Baker, T.R., Huamantupa-Chuquimaco, I., Milliken, W., Pennington, T., Tello, J.S., Pena, J.L.M., Peres, C.A., Klitgaard, B., Fuentes, A., Silman, M.R., Di Fiore, A., von Hildebrand, P., Chave, J., van Andel, T.R., Hilário, R.R., Phillips, J.F., Rivas-Torres, G., Noronha, J.C., Prieto, A., Gonzales, T., de Sá Carpanedo, R., Gonzales, G.P.G., Gómez, R.Z., de Jesus Rodrigues, D., Zent, E.L., Ruschel, A.R., Vos, V.A., Fonty, É., Junqueira, A.B., Doza, H.P.D., Hoffman, B., Zent, S., Barbosa, E.M., Malhi, Y., de Matos Bonates, L.C., de Andrade Miranda, I.P., Silva, N., Barbosa, F.R., Vela, C.I.A., Pinto, L.F.M., Rudas, A., Albuquerque, B.W., Umaña, M.N., Carrero Márquez, Y.A., van der Heijden, G., Young, K.R., Tirado, M., Correa, D.F., Sierra, R., Costa, J.B.P., Rocha, M., Vilanova Torre, E., Wang, O., Oliveira, A.A., Kalamandeen, M., Vriesendorp, C., Ramirez-Angulo, H., Holmgren, M., Nascimento, M.T., Galbraith, D., Flores, B.M., Scudeller, V.V., Cano, A., Ahuite Reategui, M.A., Mesones, I., Baider, C., Mendoza, C., Zagt, R., Urrego Giraldo, L.E., Ferreira, C., Villarroel, D., Linares-Palomino, R., Farfan-Rios, W., Casas, L.F., Cárdenas, S., Balslev, H., Torres-Lezama, A., Alexiades, M.N., Garcia-Cabrera, K., Valenzuela Gamarra, L., Valderrama Sandoval, E.H., Ramirez Arevalo, F., Hernandez, L., Sampaio, A.F., Pansini, S., Palacios Cuenca, W., de Oliveira, E.A., Pauletto, D., Levesley, A., Melgaço, K., and Pickavance, G.

Abstract

Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come. © 2020, The Author(s).

Published
2020

17. Long-term thermal sensitivity of Earth's tropical forests

Author

Sullivan, M.J.P., Lewis, S.L., Affum-Baffoe, K., Castilho, C., Costa, F., Sanchez, A.C., Ewango, C.E.N., Hubau, W., Marimon, B., Monteagudo-Mendoza, A., Qie, L., Sonké, B., Martinez, R.V., Baker, T.R., Brienen, R.J.W., Feldpausch, T.R., Galbraith, D., Gloor, M., Malhi, Y., Aiba, S.-I., Alexiades, M.N., Almeida, E.C., de Oliveira, E.A., Dávila, E.Á., Loayza, P.A., Andrade, A., Vieira, S.A., Aragão, L.E.O.C., Araujo-Murakami, A., Arets, E.J.M.M., Arroyo, L., Ashton, P., Aymard C, G., Baccaro, F.B., Banin, L.F., Baraloto, C., Camargo, P.B., Barlow, J., Barroso, J., Bastin, J.-F., Batterman, S.A., Beeckman, H., Begne, S.K., Bennett, A.C., Berenguer, E., Berry, N., Blanc, L., Boeckx, P., Bogaert, J., Bonal, D., Bongers, F., Bradford, M., Brearley, F.Q., Brncic, T., Brown, F., Burban, B., Camargo, J.L., Castro, W., Céron, C., Ribeiro, S.C., Moscoso, V.C., Chave, J., Chezeaux, E., Clark, C.J., de Souza, F.C., Collins, M., Comiskey, J.A., Valverde, F.C., Medina, M.C., da Costa, L., Dančák, M., Dargie, G.C., Davies, S., Cardozo, N.D., de Haulleville, T., de Medeiros, M.B., Del Aguila Pasquel, J., Derroire, G., Di Fiore, A., Doucet, J.-L., Dourdain, A., Droissant, V., Duque, L.F., Ekoungoulou, R., Elias, F., Erwin, T., Esquivel-Muelbert, A., Fauset, S., Ferreira, J., Llampazo, G.F., Foli, E., Ford, A., Gilpin, M., Hall, J.S., Hamer, K.C., Hamilton, A.C., Harris, D.J., Hart, T.B., Hédl, R., Herault, B., Herrera, R., Higuchi, N., Hladik, A., Coronado, E.H., Huamantupa-Chuquimaco, I., Huasco, W.H., Jeffery, K.J., Jimenez-Rojas, E., Kalamandeen, M., Djuikouo, M.N.K., Kearsley, E., Umetsu, R.K., Kho, L.K., Killeen, T., Kitayama, K., Klitgaard, B., Koch, A., Labrière, N., Laurance, W., Laurance, S., Leal, M.E., Levesley, A., Lima, A.J.N., Lisingo, J., Lopes, A.P., Lopez-Gonzalez, G., Lovejoy, T., Lovett, J.C., Lowe, R., Magnusson, W.E., Malumbres-Olarte, J., Manzatto, ÂG., Marimon B.H., Jr, Marshall, A.R., Marthews, T., de Almeida Reis, S.M., Maycock, C., Melgaço, K., Mendoza, C., Metali, F., Mihindou, V., Milliken, W., Mitchard, E.T.A., Morandi, P.S., Mossman, H.L., Nagy, L., Nascimento, H., Neill, D., Nilus, R., Vargas, P.N., Palacios, W., Camacho, N.P., Peacock, J., Pendry, C., Peñuela Mora, M.C., Pickavance, G.C., Pipoly, J., Pitman, N., Playfair, M., Poorter, L., Poulsen, J.R., Poulsen, A.D., Preziosi, R., Prieto, A., Primack, R.B., Ramírez-Angulo, H., Reitsma, J., Réjou-Méchain, M., Correa, Z.R., de Sousa, T.R., Bayona, L.R., Roopsind, A., Rudas, A., Rutishauser, E., Abu Salim, K., Salomão, R.P., Schietti, J., Sheil, D., Silva, R.C., Espejo, J.S., Valeria, C.S., Silveira, M., Simo-Droissart, M., Simon, M.F., Singh, J., Soto Shareva, Y.C., Stahl, C., Stropp, J., Sukri, R., Sunderland, T., Svátek, M., Swaine, M.D., Swamy, V., Taedoumg, H., Talbot, J., Taplin, J., Taylor, D., Ter Steege, H., Terborgh, J., Thomas, R., Thomas, S.C., Torres-Lezama, A., Umunay, P., Gamarra, L.V., van der Heijden, G., van der Hout, P., van der Meer, P., van Nieuwstadt, M., Verbeeck, H., Vernimmen, R., Vicentini, A., Vieira, I.C.G., Torre, E.V., Vleminckx, J., Vos, V., Wang, O., White, L.J.T., Willcock, S., Woods, J.T., Wortel, V., Young, K., Zagt, R., Zemagho, L., Zuidema, P.A., Zwerts, J.A., Phillips, O.L., Sullivan, M.J.P., Lewis, S.L., Affum-Baffoe, K., Castilho, C., Costa, F., Sanchez, A.C., Ewango, C.E.N., Hubau, W., Marimon, B., Monteagudo-Mendoza, A., Qie, L., Sonké, B., Martinez, R.V., Baker, T.R., Brienen, R.J.W., Feldpausch, T.R., Galbraith, D., Gloor, M., Malhi, Y., Aiba, S.-I., Alexiades, M.N., Almeida, E.C., de Oliveira, E.A., Dávila, E.Á., Loayza, P.A., Andrade, A., Vieira, S.A., Aragão, L.E.O.C., Araujo-Murakami, A., Arets, E.J.M.M., Arroyo, L., Ashton, P., Aymard C, G., Baccaro, F.B., Banin, L.F., Baraloto, C., Camargo, P.B., Barlow, J., Barroso, J., Bastin, J.-F., Batterman, S.A., Beeckman, H., Begne, S.K., Bennett, A.C., Berenguer, E., Berry, N., Blanc, L., Boeckx, P., Bogaert, J., Bonal, D., Bongers, F., Bradford, M., Brearley, F.Q., Brncic, T., Brown, F., Burban, B., Camargo, J.L., Castro, W., Céron, C., Ribeiro, S.C., Moscoso, V.C., Chave, J., Chezeaux, E., Clark, C.J., de Souza, F.C., Collins, M., Comiskey, J.A., Valverde, F.C., Medina, M.C., da Costa, L., Dančák, M., Dargie, G.C., Davies, S., Cardozo, N.D., de Haulleville, T., de Medeiros, M.B., Del Aguila Pasquel, J., Derroire, G., Di Fiore, A., Doucet, J.-L., Dourdain, A., Droissant, V., Duque, L.F., Ekoungoulou, R., Elias, F., Erwin, T., Esquivel-Muelbert, A., Fauset, S., Ferreira, J., Llampazo, G.F., Foli, E., Ford, A., Gilpin, M., Hall, J.S., Hamer, K.C., Hamilton, A.C., Harris, D.J., Hart, T.B., Hédl, R., Herault, B., Herrera, R., Higuchi, N., Hladik, A., Coronado, E.H., Huamantupa-Chuquimaco, I., Huasco, W.H., Jeffery, K.J., Jimenez-Rojas, E., Kalamandeen, M., Djuikouo, M.N.K., Kearsley, E., Umetsu, R.K., Kho, L.K., Killeen, T., Kitayama, K., Klitgaard, B., Koch, A., Labrière, N., Laurance, W., Laurance, S., Leal, M.E., Levesley, A., Lima, A.J.N., Lisingo, J., Lopes, A.P., Lopez-Gonzalez, G., Lovejoy, T., Lovett, J.C., Lowe, R., Magnusson, W.E., Malumbres-Olarte, J., Manzatto, ÂG., Marimon B.H., Jr, Marshall, A.R., Marthews, T., de Almeida Reis, S.M., Maycock, C., Melgaço, K., Mendoza, C., Metali, F., Mihindou, V., Milliken, W., Mitchard, E.T.A., Morandi, P.S., Mossman, H.L., Nagy, L., Nascimento, H., Neill, D., Nilus, R., Vargas, P.N., Palacios, W., Camacho, N.P., Peacock, J., Pendry, C., Peñuela Mora, M.C., Pickavance, G.C., Pipoly, J., Pitman, N., Playfair, M., Poorter, L., Poulsen, J.R., Poulsen, A.D., Preziosi, R., Prieto, A., Primack, R.B., Ramírez-Angulo, H., Reitsma, J., Réjou-Méchain, M., Correa, Z.R., de Sousa, T.R., Bayona, L.R., Roopsind, A., Rudas, A., Rutishauser, E., Abu Salim, K., Salomão, R.P., Schietti, J., Sheil, D., Silva, R.C., Espejo, J.S., Valeria, C.S., Silveira, M., Simo-Droissart, M., Simon, M.F., Singh, J., Soto Shareva, Y.C., Stahl, C., Stropp, J., Sukri, R., Sunderland, T., Svátek, M., Swaine, M.D., Swamy, V., Taedoumg, H., Talbot, J., Taplin, J., Taylor, D., Ter Steege, H., Terborgh, J., Thomas, R., Thomas, S.C., Torres-Lezama, A., Umunay, P., Gamarra, L.V., van der Heijden, G., van der Hout, P., van der Meer, P., van Nieuwstadt, M., Verbeeck, H., Vernimmen, R., Vicentini, A., Vieira, I.C.G., Torre, E.V., Vleminckx, J., Vos, V., Wang, O., White, L.J.T., Willcock, S., Woods, J.T., Wortel, V., Young, K., Zagt, R., Zemagho, L., Zuidema, P.A., Zwerts, J.A., and Phillips, O.L.

Abstract

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (-9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth's climate.

Published
2020

18. [[delta].sup.13]C of fluvial mollusk shells (Rhone River): a proxy for dissolved inorganic carbon?

Author

Aucour, Anne-Marie, Sheppard, Simon M.F., and Savoye, Regine

Subjects
Carbon -- Environmental aspects, Mollusks -- Physiological aspects, Shells -- Chemical properties, Water chemistry -- Analysis, Water chemistry -- Environmental aspects, Earth sciences
Abstract

The relationship between the [[delta].sup.13] C of dissolved inorganic carbon (DIC) and modern mollusk aragonite from rivers was calibrated for the purpose of reconstructing DIC paleochemistry from the shell record. The [[delta].sup.13]C values of aragonitic bivalves (Dreissena polymorpha, Corbicula fluminea), prosobranch gastropods (Bithynia tentaculata, Theodoxus fluviatilis, Viviparus viviparus), and an air-breathing pulmonate gastropod (Limnea auricularia) were analyzed from several locations on the Rhone River (-13.7% to -6.0%) and its major tributary, the Saone River (-11.4% to--10.2%). The [[delta].sup.13][C.sub.DIC] varied from -11.5% to -7.5%, and the [[delta].sup.13]C of particulate inorganic matter (POM) varied from -31.7% to -25.4%. At a given site, the [[delta].sup.13]C of all species except the pulmonate were within 1% of each other. Whole-shell [[delta].sup.13]C correlated positively with [[delta].sup.13][C.sub.DIC], with a slope close to unity. Bioaragonite-DIC fractionations were 0-1.5% for bivalves and 0-2.7% for gastropods (excluding the pulmonates). Applying these fractionations, bivalves that live in open water are a reliable proxy, monitoring the average [[delta].sup.13][C.sub.DIC] value to within its natural ~2% temporal variation within the growth period. For the suspension feeders (bivalves) using POM as a food source, the [[delta].sup.13]C of whole shells and bulk POM indicated that the incorporation of carbon derived from respiratory sources lay in the range 10-30%. Fine-scale analyses of growth increments of C. fluminea could not be related simply to [[delta].sup.13]C DIC because metabolic and seasonal variations in [[delta].sup.13][C.sub.DIC] produced similar isotopic fluctuations ([less than or equal to] 2.5%).

Published
2003

23. delta18O values coexisting brachiopods and fish: temperature differences and estimates of paleo-water depths

Author

Picard, Stephanie, Garcia, Jean-Pierre, Lecuyer, Christophe, Sheppard, Simon M.F., Cappetta, Henri, and Emig, Christian C.

Subjects
Brachiopoda -- Physiological aspects, Fishes -- Effect of water temperature on, Paleoceanography -- Research, Earth sciences
Abstract

To estimate vertical thermal gradients and paleo-water depths to marine platforms we present a new method based on the difference between [Delta]18O values of contemporaneous brachiopod carbonate and fish phosphate. Present-day marine fauna of well-known ecology from the surface to the sea floor record isotopic temperatures that agree with measured temperatures. We predict distributions of isotopic data that result from sampling strategy, basin morphology, and fauna ecology and discuss limitations. Application of the method to the Jurassic Paris-London basin gives vertical thermal variations of up to 14 [degrees] C associated with depths varying from a few meters to 170 [+ or -] 30 m. The estimated depths are minimum values and are greater than those estimated from sedimentological criteria for this ancient epicontinental sea.

Published
1998

24. Fluid flow vs. scale of shear zones in the lower continental crust and the granulite paradox

Author

Pili, Eric, Sheppard, Simon M.F., Lardeaux, Jean-Marc, Martelat, Jean-Emmanuel, and Nicolett, Christian

Subjects
Shear flow -- Research, Petrofabric analysis -- Usage, Marble -- Research, Carbon -- Isotopes, Isotopes -- Research, Earth sciences
Abstract

The external or internal origin of C[O.sub.2] and [H.sub.2]O in marbles and metabasites from a large-scale granulite section is related to their structural setting: outside shear zones, within major shear zones ([approximately equal to]25 km wide by >340 km long), or within minor shear zones (

Published
1997

27. Rarity of monodominance in hyperdiverse Amazonian forests

Author

Ter Steege, H., Henkel, T.W., Helal, N., Marimon, B.S., Marimon-Junior, B.H., Huth, A., Groeneveld, J., Sabatier, D., Coelho, L.S., Filho, D.A.L., Salomão, R.P., Amaral, I.L., Matos, F.D.A., Castilho, C.V., Phillips, O.L., Guevara, J.E., Carim, M.J.V., Cárdenas López, D., Magnusson, W.E., Wittmann, F., Irume, M.V., Martins, M.P., Guimarães, J.R.D.S., Molino, J.-F., Bánki, O.S., Piedade, M.T.F., Pitman, N.C.A., Mendoza, A.M., Ramos, J.F., Luize, B.G., Moraes de Leão Novo, E.M., Núñez Vargas, P., Silva, T.S.F., Venticinque, E.M., Manzatto, A.G., Reis, N.F.C., Terborgh, J., Casula, K.R., Honorio Coronado, E.N., Montero, J.C., Feldpausch, T.R., Duque, A., Costa, F.R.C., Arboleda, N.C., Schöngart, J., Killeen, T.J., Vasquez, R., Mostacedo, B., Demarchi, L.O., Assis, R.L., Baraloto, C., Engel, J., Petronelli, P., Castellanos, H., de Medeiros, M.B., Quaresma, A., Simon, M.F., Andrade, A., Camargo, J.L., Laurance, S.G.W., Laurance, W.F., Rincón, L.M., Schietti, J., Sousa, T.R., de Sousa Farias, E., Lopes, M.A., Magalhães, J.L.L., Mendonça Nascimento, H.E., Lima de Queiroz, H., Aymard C, G.A., Brienen, R., Revilla, J.D.C., Vieira, I.C.G., Cintra, B.B.L., Stevenson, P.R., Feitosa, Y.O., Duivenvoorden, J.F., Mogollón, H.F., Araujo-Murakami, A., Ferreira, L.V., Lozada, J.R., Comiskey, J.A., de Toledo, J.J., Damasco, G., Dávila, N., Draper, F., García-Villacorta, R., Lopes, A., Vicentini, A., Alonso, A., Dallmeier, F., Gomes, V.H.F., Lloyd, J., Neill, D., de Aguiar, D.P.P., Arroyo, L., Carvalho, F.A., de Souza, F.C., do Amaral, D.D., Feeley, K.J., Gribel, R., Pansonato, M.P., Barlow, J., Berenguer, E., Ferreira, J., Fine, P.V.A., Guedes, M.C., Jimenez, E.M., Licona, J.C., Peñuela Mora, M.C., Villa, B., Cerón, C., Maas, P., Silveira, M., Stropp, J., Thomas, R., Baker, T.R., Daly, D., Dexter, K.G., Huamantupa-Chuquimaco, I., Milliken, W., Pennington, T., Ríos Paredes, M., Fuentes, A., Klitgaard, B., Pena, J.L.M., Peres, C.A., Silman, M.R., Tello, J.S., Chave, J., Cornejo Valverde, F., Di Fiore, A., Hilário, R.R., Phillips, J.F., Rivas-Torres, G., van Andel, T.R., von Hildebrand, P., Noronha, J.C., Barbosa, E.M., Barbosa, F.R., de Matos Bonates, L.C., Carpanedo, R.S., Dávila Doza, H.P., Fonty, É., GómeZárate Z, R., Gonzales, T., Gallardo Gonzales, G.P., Hoffman, B., Junqueira, A.B., Malhi, Y., Miranda, I.P.A., Pinto, L.F.M., Prieto, A., Rodrigues, D.J., Rudas, A., Ruschel, A.R., Silva, N., Vela, C.I.A., Vos, V.A., Zent, E.L., Zent, S., Weiss Albuquerque, B., Cano, A., Carrero Márquez, Y.A., Correa, D.F., Costa, J.B.P., Flores, B.M., Galbraith, D., Holmgren, M., Kalamandeen, M., Nascimento, M.T., Oliveira, A.A., Ramirez-Angulo, H., Rocha, M., Scudeller, V.V., Sierra, R., Tirado, M., Umaña Medina, M.N., van der Heijden, G., Vilanova Torre, E., Vriesendorp, C., Wang, O., Young, K.R., Ahuite Reategui, M.A., Baider, C., Balslev, H., Cárdenas, S., Casas, L.F., Farfan-Rios, W., Ferreira, C., Linares-Palomino, R., Mendoza, C., Mesones, I., Torres-Lezama, A., Giraldo, L.E.U., Villarroel, D., Zagt, R., Alexiades, M.N., de Oliveira, E.A., Garcia-Cabrera, K., Hernandez, L., Palacios Cuenca, W., Pansini, S., Pauletto, D., Ramirez Arevalo, F., Sampaio, A.F., Sandoval, E.H.V., Valenzuela Gamarra, L., Levesley, A., Pickavance, G., Melgaço, K., Ter Steege, H., Henkel, T.W., Helal, N., Marimon, B.S., Marimon-Junior, B.H., Huth, A., Groeneveld, J., Sabatier, D., Coelho, L.S., Filho, D.A.L., Salomão, R.P., Amaral, I.L., Matos, F.D.A., Castilho, C.V., Phillips, O.L., Guevara, J.E., Carim, M.J.V., Cárdenas López, D., Magnusson, W.E., Wittmann, F., Irume, M.V., Martins, M.P., Guimarães, J.R.D.S., Molino, J.-F., Bánki, O.S., Piedade, M.T.F., Pitman, N.C.A., Mendoza, A.M., Ramos, J.F., Luize, B.G., Moraes de Leão Novo, E.M., Núñez Vargas, P., Silva, T.S.F., Venticinque, E.M., Manzatto, A.G., Reis, N.F.C., Terborgh, J., Casula, K.R., Honorio Coronado, E.N., Montero, J.C., Feldpausch, T.R., Duque, A., Costa, F.R.C., Arboleda, N.C., Schöngart, J., Killeen, T.J., Vasquez, R., Mostacedo, B., Demarchi, L.O., Assis, R.L., Baraloto, C., Engel, J., Petronelli, P., Castellanos, H., de Medeiros, M.B., Quaresma, A., Simon, M.F., Andrade, A., Camargo, J.L., Laurance, S.G.W., Laurance, W.F., Rincón, L.M., Schietti, J., Sousa, T.R., de Sousa Farias, E., Lopes, M.A., Magalhães, J.L.L., Mendonça Nascimento, H.E., Lima de Queiroz, H., Aymard C, G.A., Brienen, R., Revilla, J.D.C., Vieira, I.C.G., Cintra, B.B.L., Stevenson, P.R., Feitosa, Y.O., Duivenvoorden, J.F., Mogollón, H.F., Araujo-Murakami, A., Ferreira, L.V., Lozada, J.R., Comiskey, J.A., de Toledo, J.J., Damasco, G., Dávila, N., Draper, F., García-Villacorta, R., Lopes, A., Vicentini, A., Alonso, A., Dallmeier, F., Gomes, V.H.F., Lloyd, J., Neill, D., de Aguiar, D.P.P., Arroyo, L., Carvalho, F.A., de Souza, F.C., do Amaral, D.D., Feeley, K.J., Gribel, R., Pansonato, M.P., Barlow, J., Berenguer, E., Ferreira, J., Fine, P.V.A., Guedes, M.C., Jimenez, E.M., Licona, J.C., Peñuela Mora, M.C., Villa, B., Cerón, C., Maas, P., Silveira, M., Stropp, J., Thomas, R., Baker, T.R., Daly, D., Dexter, K.G., Huamantupa-Chuquimaco, I., Milliken, W., Pennington, T., Ríos Paredes, M., Fuentes, A., Klitgaard, B., Pena, J.L.M., Peres, C.A., Silman, M.R., Tello, J.S., Chave, J., Cornejo Valverde, F., Di Fiore, A., Hilário, R.R., Phillips, J.F., Rivas-Torres, G., van Andel, T.R., von Hildebrand, P., Noronha, J.C., Barbosa, E.M., Barbosa, F.R., de Matos Bonates, L.C., Carpanedo, R.S., Dávila Doza, H.P., Fonty, É., GómeZárate Z, R., Gonzales, T., Gallardo Gonzales, G.P., Hoffman, B., Junqueira, A.B., Malhi, Y., Miranda, I.P.A., Pinto, L.F.M., Prieto, A., Rodrigues, D.J., Rudas, A., Ruschel, A.R., Silva, N., Vela, C.I.A., Vos, V.A., Zent, E.L., Zent, S., Weiss Albuquerque, B., Cano, A., Carrero Márquez, Y.A., Correa, D.F., Costa, J.B.P., Flores, B.M., Galbraith, D., Holmgren, M., Kalamandeen, M., Nascimento, M.T., Oliveira, A.A., Ramirez-Angulo, H., Rocha, M., Scudeller, V.V., Sierra, R., Tirado, M., Umaña Medina, M.N., van der Heijden, G., Vilanova Torre, E., Vriesendorp, C., Wang, O., Young, K.R., Ahuite Reategui, M.A., Baider, C., Balslev, H., Cárdenas, S., Casas, L.F., Farfan-Rios, W., Ferreira, C., Linares-Palomino, R., Mendoza, C., Mesones, I., Torres-Lezama, A., Giraldo, L.E.U., Villarroel, D., Zagt, R., Alexiades, M.N., de Oliveira, E.A., Garcia-Cabrera, K., Hernandez, L., Palacios Cuenca, W., Pansini, S., Pauletto, D., Ramirez Arevalo, F., Sampaio, A.F., Sandoval, E.H.V., Valenzuela Gamarra, L., Levesley, A., Pickavance, G., and Melgaço, K.

Abstract

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such “monodominant” forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors.

Published
2019

31. Biological and geophysical feedbacks with fire in the Earth system

Author

Archibald, S., Lehmann, C.E.R., Belcher, C.M., Bond, W.J., Bradstock, R.A., Daniau, A.-L., Dexter, K.G., Forrestel, E.J., Greve, M., He, T., Higgins, S.I., Hoffmann, W.A., Lamont, B.B., McGlinn, D.J., Moncrieff, G.R., Osborne, C.P., Pausas, J.G., Price, O., Ripley, B.S., Rogers, B.M., Schwilk, D.W., Simon, M.F., Turetsky, M.R., Van der Werf, G.R., Zanne, A.E., Archibald, S., Lehmann, C.E.R., Belcher, C.M., Bond, W.J., Bradstock, R.A., Daniau, A.-L., Dexter, K.G., Forrestel, E.J., Greve, M., He, T., Higgins, S.I., Hoffmann, W.A., Lamont, B.B., McGlinn, D.J., Moncrieff, G.R., Osborne, C.P., Pausas, J.G., Price, O., Ripley, B.S., Rogers, B.M., Schwilk, D.W., Simon, M.F., Turetsky, M.R., Van der Werf, G.R., and Zanne, A.E.

Abstract

Roughly 3% of the Earth's land surface burns annually, representing a critical exchange of energy and matter between the land and atmosphere via combustion. Fires range from slow smouldering peat fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel moisture, prevailing climate, and weather conditions. While the links between biogeochemistry, climate and fire are widely studied within Earth system science, these relationships are also mediated by fuels—namely plants and their litter—that are the product of evolutionary and ecological processes. Fire is a powerful selective force and, over their evolutionary history, plants have evolved traits that both tolerate and promote fire numerous times and across diverse clades. Here we outline a conceptual framework of how plant traits determine the flammability of ecosystems and interact with climate and weather to influence fire regimes. We explore how these evolutionary and ecological processes scale to impact biogeochemical and Earth system processes. Finally, we outline several research challenges that, when resolved, will improve our understanding of the role of plant evolution in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire and vegetation, as well as patterns of fire over geological time, requires research that incorporates evolutionary biology, ecology, biogeography, and the biogeosciences.

Published
2018

33. Echo Time‐Dependence of Observed Lung T1 in Patients With Cystic Fibrosis and Correlation With Clinical Metrics.

Author

Triphan, Simon M.F., Stahl, Mirjam, Jobst, Bertram J., Sommerburg, Olaf, Kauczor, Hans‐Ulrich, Schenk, Jens‐Peter, Alrajab, Abdulsattar, Eichinger, Monika, Mall, Marcus A., and Wielpütz, Mark O.

Subjects
CYSTIC fibrosis, CHILD patients, LUNGS, LUNG diseases, ECHO
Abstract

Background: Noninvasive monitoring of early abnormalities and therapeutic intervention in cystic fibrosis (CF) lung disease using MRI is important. Lung T1 mapping has shown potential for local functional imaging without contrast material. Recently, it was discovered that observed lung T1 depends on the measurement echo time (TE). Purpose: To examine TE‐dependence of observed T1 in patients with CF and its correlation with clinical metrics. Study Type: Prospective. Population: In all, 75 pediatric patients with CF (8.6 ± 6.1 years, range 0.1–23 years), with 32 reexamined after 1 year. Field Strength/Sequence: Patients were examined at 1.5T using an established MRI protocol and a multiecho inversion recovery 2D ultrashort echo time (UTE) sequence for T1(TE) mapping at five TEs including TE1 = 70 μs. Assessment: Morphological and perfusion MRI were assessed by a radiologist (M.W.) with 11 years of experience using an established CF‐MRI scoring system. T1(TE) was quantified automatically. Clinical data including spirometry (FEV1pred%) and lung clearance index (LCI) were collected. Statistical Tests: T1(TE) was correlated with the CF‐MRI score, clinical data, and LCI. Results: T1(TE) showed a different curvature in CF than in healthy adults: T1 at TE1 was shorter in CF (1157 ms ± 73 ms vs. 1047 ms ± 70 ms, P < 0.001), but longer at TE3 (1214 ms ± 72 ms vs. 1314 ms ± 68 ms, P < 0.001) and later TEs. The correlations of T1(TE) with patient age (ρTE1‐TE5 = −0.55, −0.44, −0.24, −0.30, −0.22), and LCI (ρTE1‐TE5 = −0.43, −0.42, −0.33, 0.27, −0.22) were moderate at ultra‐short to short TE (P < 0.001) but decreased for longer TE. Moderate but similar correlations at all TE were found with MRI perfusion score (ρTE1‐TE5 = −0.43, −0.51, −0.47, −0.46, −0.44) and FEV1pred% (ρTE1‐TE5 = +0.44, +0.44, +0.43, +0.40, +0.39) (P < 0.05). Data Conclusion: TE should be considered when measuring lung T1, since observed differences between CF and healthy subjects strongly depend on TE. The different variation of correlation coefficients with TE for structural vs. functional metrics implies that TE‐dependence holds additional information which may help to discern effects of tissue structural abnormalities and abnormal perfusion. Level of Evidence: 2 Technical Efficacy Stage: 1 J. MAGN. RESON. IMAGING 2020;52:1645–1654. [ABSTRACT FROM AUTHOR]

Published
2020
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35. Non-contrast enhanced magnetic resonance imaging detects mosaic signal intensity in early cystic fibrosis lung disease

Author

Leutz-Schmidt, Patricia, primary, Stahl, Mirjam, additional, Sommerburg, Olaf, additional, Eichinger, Monika, additional, Puderbach, Michael U., additional, Schenk, Jens-Peter, additional, Alrajab, Abdulsattar, additional, Triphan, Simon M.F., additional, Kauczor, Hans-Ulrich, additional, Mall, Marcus A., additional, and Wielpütz, Mark O., additional

Published
2018
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36. GOLD-Grade Specific Disease Characterization and Phenotyping of COPD Using Quantitative Computed Tomography in the Nationwide COSYCONET Multicenter Trial in Germany.

Author

Konietzke, Philip, Weinheimer, Oliver, Triphan, Simon M.F., Nauck, Sebastian, Wuennemann, Felix, Konietzke, Marilisa, Jobst, Bertram J., Jörres, Rudolf A., Vogelmeier, Claus F., Heussel, Claus P., Kauczor, Hans-Ulrich, Biederer, Jürgen, and Wielpütz, Mark O.

Abstract

Introduction: The aim of this study was to apply quantitative computed tomography (QCT) for GOLD-grade specific disease characterization and phenotyping of air-trapping, emphysema, and airway abnormalities in patients with chronic obstructive pulmonary disease (COPD) from a nationwide cohort study. Methods: As part of the COSYCONET multicenter study, standardized CT in ex- and inspiration, lung function assessment (FEV1/FVC), and clinical scores (BODE index) were prospectively acquired in 525 patients (192 women, 327 men, aged 65.7 ± 8.5 years) at risk for COPD and at GOLD1–4. QCT parameters such as total lung volume (TLV), emphysema index (EI), parametric response mapping (PRM) for emphysema (PRMEmph) and functional small airway disease (PRMfSAD), total airway volume (TAV), wall percentage (WP), and total diameter (TD) were computed using automated software. Results: TLV, EI, PRMfSAD, and PRMEmph increased incrementally with each GOLD grade (p < 0.001). Aggregated WP5–10 of subsegmental airways was higher from GOLD1 to GOLD3 and lower again at GOLD4 (p < 0.001), whereas TD5–10 was significantly dilated only in GOLD4 (p < 0.001). Fifty-eight patients were phenotyped as “non-airway non-emphysema type,” 202 as “airway type,” 96 as “emphysema type,” and 169 as “mixed type.” FEV1/FVC was best in “non-airway non-emphysema type” compared to other phenotypes, while “mixed type” had worst FEV1/FVC (p < 0.001). BODE index was 0.56 ± 0.72 in the “non-airway non-emphysema type” and highest with 2.55 ± 1.77 in “mixed type” (p < 0.001). Conclusion: QCT demonstrates increasing hyperinflation and emphysema depending on the GOLD grade, while airway wall thickening increases until GOLD3 and airway dilatation occur in GOLD4. QCT identifies four disease phenotypes with implications for lung function and prognosis. [ABSTRACT FROM AUTHOR]

Published
2024
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39. δ13C and stomatal number variability in the Cretaceous conifer Frenelopsis

Author

Bernard Gomez, Simon M.F. Sheppard, Frédéric Thévenard, and Anne-Marie Aucour

Subjects
Soil salinity, δ13C, Cuticle, Paleontology, Oceanography, Cretaceous, Salinity, chemistry.chemical_compound, Isotope fractionation, Total inorganic carbon, chemistry, Botany, Carbonate, Ecology, Evolution, Behavior and Systematics, Geology, Earth-Surface Processes
Abstract

The 13 C/ 12 C ratios of leaves of the conifer morphotype Frenelopsis were measured to decipher the influences of water and salt stress on stomatal density (SD), epidermal cell density (ECD) and stomatal index (SI). Three morphospecies were analyzed: F . ugnaensis from freshwater fluvio-lacustrine deposits (Upper Barremian), F . turolensis and alata from coastal deposits (Lower-Middle Albian and Upper Albian respectively). The cuticle δ 13 C values show a large variation from − 28‰ to − 21‰. Comparison with previously published marine carbonate δ 13 C records indicate that the difference in cuticle δ 13 C between the different deposits are mainly due to difference in CO 2 -plant isotope fractionation rather than to change in isotopic composition of inorganic carbon in the atmosphere and ocean. The less negative δ 13 C and wide range in δ 13 C of F . turolensis and alata (− 27.5 to − 21‰), compared to F . ugnaensis , (− 28 to − 25‰) are interpreted as a result of salt and/or water stress. The data as a whole yield a good relationship between the 13 C/ 12 C ratio and SD ( r = 0.67, n = 42, p r = 0.53, n = 41, p F. ugnaensis decreases with increasing δ 13 C value ( r = − 0.57, n = 15, p = 0.026) as well as a decrease of SI ( r = − 0.62, n = 15, p = 0.013), possibly reflecting warmer and drier conditions. Average SI of F. alata does not significantly change with δ 13 C and inferred soil salinity in contrast to SD ( p

Published
2008
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40. Phylogeny, diversity, geographical distribution, and host range of legume-nodulating betaproteobacteria : what Is the role of plant taxonomy ?

Author

Moulin, Lionel, James, E.K., Klonowska, Agnieszka, Miana de Faria, S., Simon, M.F., and De Bruijn, F.J (ed.)

Subjects
food and beverages
Abstract

he class Betaproteobacteria contains several related genera that associate closely (and non-pathogenically) with plants. Recent studies have highlighted the emerging importance of newly-discovered legume-nodulating bacteria in the genera Burkholderia and Cupriavidus, the so-called “beta-rhizobia”. Nine species of nodulating burkholderias have been described so far, most being ancient (ca. 50 my) symbionts of many of the 500 species in the large genus Mimosa, but also of several other species of the legume tribe Mimoseae (Mimosoideae). Nodulation in these species by beta-rhizobia is thought to have emerged through the ancient lateral transfer of nodulation genes to their endophytic ancestors, followed by mainly vertical transfer (horizontal transfer being also detected in a few species), as illustrated by the parallelism between phylogenies of taxonomic and symbiotic markers. In contrast to Burkholderia, the most studied Cupriavidus species, C. taiwanensis, is considered to be a very recent legume symbiont that only nodulates a few invasive Mimosa spp. On the plant side, genera belonging to the tribe Mimoseae (especially those in the Piptadenia Group, which includes the genera Mimosa and Piptadenia) and several species in Papilionoid genera endemic to the Fynbos in the Cape region of South Africa exhibit particular affinities for beta-rhizobia. Legume taxonomy thus appears to give some insights into the potential nodulation of plants by beta-rhizobia. This is particularly exemplified by the genus Mimosa, within which there are clades of geographically-isolated endemics that clearly have evolved to have preferences for specific symbiont types (either alpha- or beta-proteobacterial). On the other hand, although many of the relatives of Mimosa (e.g., species in Piptadenia) share their preferences for beta-rhizobial symbionts, this is not always the case, and, indeed, there is no obvious strict pattern of coevolution between species in the wider tribe Mimoseae and their symbionts (beta-rhizobial or otherwise). This is discussed in terms of the broad host ranges of both symbiotic partners, and the horizontal transfer of nodulation genes between the Burkholderia species.

Published
2015

41. Carbonatite melt in oceanic upper mantle beneath the Kerguelen Archipelago

Author

Jean-Pierre Lorand, Christophe Renac, André Giret, Michel Grégoire, Guillaume Delpech, Simon M.F. Sheppard, Jean-Yves Cottin, Bertrand Moine, and Suzanne Y. O'Reilly

Subjects
Calcite, Dolomite, Geochemistry, Geology, Silicate, chemistry.chemical_compound, chemistry, Geochemistry and Petrology, Silicate minerals, Carbonatite, Carbonate, Metasomatism, Mafic
Abstract

Some mantle-derived Kerguelen harzburgite and dunite xenoliths have bulk-rock and mineral trace element compositions that provide evidence of carbonatitic metasomatism similar to that described in some continental and other oceanic settings. Rare xenoliths contain carbonates that are highly enriched in rare earth elements (REE), interpreted to be quenched, evolved carbonatitic melts. One amphibole-bearing dunite mantle wall-rock containing carbonates in small interstitial pockets (100–500 μm across) has been studied in detail. Mg-bearing calcite (MgO

Published
2004
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42. Carbon and oxygen isotope composition of Nautilus macromphalus: a record of thermocline waters off New Caledonia

Author

Simon M.F. Sheppard, Christophe Lécuyer, Hugo Bucher, and Anne-Cécile Auclair

Subjects
Isochron dating, Oxygen-18, biology, Stable isotope ratio, Carbon-13, Geology, biology.organism_classification, Isotopes of oxygen, Oceanography, Geochemistry and Petrology, Isotopes of carbon, Environmental chemistry, Nautilus macromphalus, Thermocline
Abstract

This study investigates the controls on the stable isotope composition of shell nacreous layer of a modern Nautilus macromphalus from New Caledonia. Closely spaced samples were taken both along growth lines (isochrons) and growth axis (time series). Carbon isotope compositions ( δ 13 C=−0.3‰ to 1‰ PDB) of the shell decrease in the domains of maximal growth (−0.3‰) and muscle insertion (−0.4‰). Maximal δ 13 C variations of about 1 ‰ are recorded in time series. A global ontogenetic decrease of δ 13 C values is observed for both dorsal and ventral areas (0.4‰ to 0.8‰) and can be ascribed to a metabolic effect with age or to changes in the food source. By contrast, oxygen isotope compositions are quite constant (1.1 δ 18 O

Published
2004
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43. Diagenesis and the reconstruction of paleoenvironments: A method to restore original δ18O values of carbonate and phosphate from fossil tooth enamel

Author

Patricia Grandjean, Antoine Zazzo, André Mariotti, Christophe Lécuyer, and Simon M.F. Sheppard

Subjects
Enamel paint, δ18O, Mineralogy, Tooth enamel, Apatite, Isotopes of oxygen, Diagenesis, stomatognathic diseases, chemistry.chemical_compound, medicine.anatomical_structure, stomatognathic system, chemistry, Geochemistry and Petrology, visual_art, visual_art.visual_art_medium, Hypsodont, medicine, Carbonate, Geology
Abstract

Intra-tooth δ18O variations within the carbonate (δ18Oc) and phosphate (δ18Op) components of tooth apatite were measured for Miocene and Pliocene hypsodont mammals from Afghanistan, Greece and Chad in order to evaluate the resistance of enamel to diagenetic alteration. Application of water-apatite interaction models suggest that the different kinetic behaviours of the phosphate-water and carbonate-water systems can be used to detect subtle oxygen isotope disequilibria in fossil enamel when intra-individual variations are considered. Selective alteration of the oxygen isotope composition from the carbonate component of Afghan and Greek enamels suggests inorganic isotopic exchange processes. Microbially-induced isotopic exchange for phosphate is demonstrated for the first time in enamel samples from Chad, in association with extensive recrystallization. In Chad, δ18Op values were derived from partial isotopic exchange with fossil groundwater during early diagenesis. Mass balance calculations using average carbonate content in enamel as a proxy for recrystallization, and the lowest δ18Op value of dentine as a proxy for the isotopic composition of the diagenetic fluid, indicate that diagenesis can alter δ18Op by as much as 3‰ in some enamel samples. This diagenetic alteration is also responsible for a decrease in intra-individual variations of up to 1‰ in affected specimens. The effects of diagenesis on δ18Op values of fossil enamel are not systematic, however, and can only be estimated if sequential δ18Op and δ18Oc analyses are performed on fossil enamel and dentine. Reconstruction of large temporal- or spatial-scale paleoclimates based on δ18Op analyses from mammalian teeth cannot be considered valid if enamel has been affected by bacterial activity or if the data cannot be corrected for diagenetic effects.

Published
2004
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44. δ13 C of fluvial mollusk shells (Rhône River): A proxy for dissolved inorganic carbon?

Author

Anne-Marie Aucour, Régine Savoye, and Simon M.F. Sheppard

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, biology, Aragonite, Aquatic Science, engineering.material, 010502 geochemistry & geophysics, Oceanography, biology.organism_classification, 01 natural sciences, Dreissena, Bithynia tentaculata, Viviparus viviparus, Tributary, Dissolved organic carbon, engineering, Theodoxus fluviatilis, Corbicula fluminea, 0105 earth and related environmental sciences
Abstract

The relationship between the δ13C of dissolved inorganic carbon (DIC) and modern mollusk aragonite from rivers was calibrated for the purpose of reconstructing DIC paleochemistry from the shell record. The δ13C values of aragonitic bivalves (Dreissena polymorpha, Corbicula fluminea), prosobranch gastropods (Bithynia tentaculata, Theodoxus fluviatilis, Viviparus viviparus), and an air-breathing pulmonate gastropod (Limnea auricularia) were analyzed from several locations on the Rhone River (—13.7‰ to —6.0‰) and its major tributary, the Saone River (—11.4‰ to —10.2‰). The δ13CDIC varied from —11.5‰ to —7.5‰, and the δ13C of particulate inorganic matter (POM) varied from —31.7‰ to —25.4‰. At a given site, the δ13C of all species except the pulmonate were within 1‰ of each other. Whole-shell δ13C correlated positively with δ13CDIC, with a slope close to unity. Bioaragonite—DIC fractionations were 0–1.5‰ for bivalves and 0–2.7‰ for gastropods (excluding the pulmonates). Applying these fractionations, bivalves that live in open water are a reliable proxy, monitoring the average δ13CDIC value to within its natural ~2‰ temporal variation within the growth period. For the suspension feeders (bivalves) using POM as a food source, the δ13C of whole shells and bulk POM indicated that the incorporation of carbon derived from respiratory sources lay in the range 10–30%. Fine-scale analyses of growth increments of C. fluminea could not be related simply to δ13CDIC because metabolic and seasonal variations in δ13CDIC produced similar isotopic fluctuations (≤2.5‰).

Published
2003
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45. Perturbation of the carbon cycle at the Middle/Late Jurassic transition: Geological and geochemical evidence

Author

Stephanie Picard, Fabrice Gaumet, Christophe Lécuyer, Jean-Pierre Garcia, Mathieu Rousseau, François Atrops, Gilles Dromart, and Simon M.F. Sheppard

Subjects
chemistry.chemical_compound, Paleontology, chemistry, Northern Hemisphere, General Earth and Planetary Sciences, Carbonate, Sequence stratigraphy, Greenhouse effect, Global cooling, Sea level, Geology, Latitude, Carbon cycle
Abstract

A compilation of new and published stratigraphic, paleontological and geochemical data is used to detect the reciprocal influences of carbon cycling and global environmental changes in the Jurassic. A major perturbation of the surface carbon cycling accompanied by pronounced climate and sea level fluctuations (waxing and waning of continental ice?) affected Earth history around the Middle/Late Jurassic transition (MLJT). We establish the respective timing of changes of carbonate and organic matter sedimentation, and global fluctuations of sea surface temperatures (paleobiogeography and O-isotope paleothermometry) and sea level (sequence stratigraphy), so that causative mechanisms and feedback effects can be considered. It is apparent that the global sea level rise and warming initiated in the Late Bathonian led to a constriction of carbonate platforms to low latitudes and enhanced marine organic deposition. Sea level and temperature optima were achieved several million-years later during the Middle Callovian. A detailed record of sea surface temperatures in the Northern Hemisphere based on migration of marine fauna and isotopic thermometry indicates that a drastic climatic decline set in during the early Late Callovian, just post-dating the increased capture of organic matter by marine sediments. This decline in temperature is interpreted in terms of an inverse greenhouse effect, triggered by drawdown of CO 2 consequent upon excess carbon burial. The magnitude of refrigeration and its coincidence in time with an abrupt global-scale fall of sea level are both suggestive of continental ice formation at this time. Carbonate sedimentation was jeopardized at the MLJT as a result of both global cooling and presumed P C O 2 lowering, and resumed abruptly during the Middle Oxfordian by spreading again over mid-latitude zones. Salient conclusions are that (1) the pattern of excess carbon burial, coincident with elevated temperature but followed by climatic deterioration supports the general hypothesis that a major control on Mesozoic climate was the abundance of atmospheric CO 2 ; (2) significant masses of continental ice may have formed during this part of the Jurassic and correlatively, high CO 2 levels were certainly not sustained throughout this period; (3) the global carbonate sedimentation budget correlated with the surface temperature and sea level, but the latitudinal spreading of type-tropical carbonates was not simply related to the thermal status of seawaters; (4) on a global scale, the C o r g and C i n o r g burial rates were coupled, apparently through the correlation existing between the CO 2 level and surface temperature.

Published
2003
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46. Ice age at the Middle–Late Jurassic transition?

Author

Christophe Lécuyer, Gilles Dromart, François Atrops, Jean-Pierre Garcia, Simon M.F. Sheppard, and S. Picard

Subjects
geography, geography.geographical_feature_category, δ18O, Paleontology, Geophysics, Space and Planetary Science, Geochemistry and Petrology, Paleoclimatology, Earth and Planetary Sciences (miscellaneous), Ice age, Sequence stratigraphy, Mesozoic, Glacial period, Ice sheet, Geology, Sea level
Abstract

A detailed record of sea surface temperatures in the Northern Hemisphere based on migration of marine invertebrate fauna (ammonites) and isotopic thermometry (δ18O values of shark tooth enamel) indicates a severe cooling at the Middle–Late Jurassic transition (MLJT), about 160 Ma ago. The magnitude of refrigeration (1–3°C for lower middle latitudes) and its coincidence in time with an abrupt global-scale fall of sea level documented through sequence stratigraphy are both suggestive of continental ice formation at this time. Ice sheets may have developed over the high-latitude mountainous regions of Far-East Russia. The drastic cooling just post-dated the Middle–Late Callovian widespread deposition of organic-rich marine sediments (e.g. northwestern Europe, Central Atlantic, and Arabian Peninsula). This thermal deterioration can thus be ascribed to a downdraw in atmospheric CO2 via enhanced organic carbon burial which acted as a negative feedback effect (i.e. the inverse greenhouse effect). The glacial episode of the MLJT climaxed in the Late Callovian, lasted about 2.6 Myr, and had a pronounced asymmetrical pattern composed of an abrupt (∼0.8 Myr) temperature fall opposed to a long-term (∼1.8 Myr), stepwise recovery. The glacial conditions at the MLJT reveal that atmospheric CO2 levels could have dropped temporarily to values lower than 500 ppmv during Mesozoic times.

Published
2003
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47. The Amazon River: behaviour of metals (Fe, Al, Mn) and dissolved organic matter in the initial mixing at the Rio Negro/Solimões confluence

Author

Patricia Moreira-Turcq, Patrick Seyler, Simon M.F. Sheppard, Faxiang Tao, Marc F. Benedetti, and Anne-Marie Aucour

Subjects
chemistry.chemical_classification, Total organic carbon, geography, geography.geographical_feature_category, Chemistry, chemistry.chemical_element, Geology, Manganese, Particulates, Water column, Geochemistry and Petrology, Environmental chemistry, Tributary, Dissolved organic carbon, Organic matter, Dissolution
Abstract

We studied the changes in major elements and organic carbon concentrations during the initial stage of the mixing of the black (Rio Negro) and the White (Rio Solimoes) waters in the Amazon River basin to understand the geochemical processes that could control the redistribution between particulate and dissolved fractions. Water samples were collected at six stations including the Rio Negro and the Rio Solimoes and four stations downstream from the confluence. The relative contributions of the two tributaries were determined using a triple tracer approach (d 18 O, dD, Cl � ). Particulate (>0.2 Am) and dissolved (

Published
2003
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48. Rare earth element contents of Jurassic fish and reptile teeth and their potential relation to seawater composition (Anglo-Paris Basin, France and England)

Author

Simon M.F. Sheppard, Jean-Alix Barrat, Jean-Pierre Garcia, Gilles Dromart, Stephanie Picard, and Christophe Lécuyer

Subjects
Rare-earth element, Geochemistry, Geology, Cretaceous, Sedimentary structures, Paleontology, chemistry.chemical_compound, Water column, chemistry, Geochemistry and Petrology, Clastic rock, Carbonate, Seawater, Siliciclastic
Abstract

The rare earth element (REE) chemistry of Jurassic shelf seawater from western Europe (Anglo-Paris Basin) was investigated by analyzing the fish and reptile teeth deposited in shallow to deeper water (

Published
2002
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49. Compartmentalisation of fluid migration pathways in the sub-Andean Zone, Bolivia

Author

Isabelle Moretti, Pierre Labaume, Jacques Boulègue, Simon M.F. Sheppard, Université Grenoble Alpes (UGA), École normale supérieure de Lyon (ENS de Lyon), Institut de Physique du Globe de Paris (IPGP), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)

Subjects
geography, geography.geographical_feature_category, Mineralogy, Authigenic, Fault (geology), Diagenesis, Geophysics, [SDU]Sciences of the Universe [physics], Fluid dynamics, Foothills, Precipitation, Petrology, human activities, Quartz, Foreland basin, Geology, Earth-Surface Processes
Abstract

International audience; Numerous observations indicate that faults play a major role on the migration pathways of fluids in the Bolivian sub-Andean Zone. Most oil seeps in the foothills are located on faults, but oil fields in the foredeep are closed by faults. In the foothills, analysis of cements in fractures inside and around fault zones indicates that the faults act as barriers for transversal migration but can be preferential lateral migration pathways for both hydrocarbons and water. A detailed study of these apparent contradictions suggests that the hydraulic behaviour of faults changes with depth in relation with sandstone diagenesis, but it is strain-independent. From microstructural analyses of fault zones, we suggest that the main controlling factor is temperature, which facilitates or inhibits quartz precipitation. This result implies that the same fault is a barrier for lateral and transversal migration at depths >3 km, due to sealing of fractures by authigenic quartz at T>80 °C, and is a lateral drain in its shallower parts. As a result, the various thrust sheets are isolated from a hydraulic point of view, whereas migration in the foreland may take place over long distances (>100 km).

Published
2002
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50. Presence and geodynamic significance of Cambro-Ordovician series of SE Karakoram (N Pakistan)

Author

Igor M. Villa, Simon M.F. Sheppard, Massimo Oddone, Arnaud Pêcher, Elisabeth Carrio, Yann Rolland, Christian Picard, Université Grenoble Alpes (UGA), and École normale supérieure de Lyon (ENS de Lyon)

Subjects
Trace element, Paleontology, Tectonics, Precambrian, Geophysics, Basement (geology), [SDU]Sciences of the Universe [physics], Ultramafic rock, 550 Earth sciences & geology, Sedimentary rock, Accretion (geology), Geology, Amphibole, Earth-Surface Processes
Abstract

International audience; New geological, geochemical and geochronological data from the Southern Karakoram (NE Pakistan) indicate the presence of several unexpectedly old and well preserved units along the Asian margin: (1) a Precambrian basement, displaying a minimum amphibole Ar-Ar age of 651 Ma; (2) a thick Cambro-Ordovician platform-type sedimentary unit overlying the Precambrian basement. These series are dated by graptolite and crinoid faunas, and are confirmed by concordant 87Sr/ 86Sr and 13C "ages" of the marbles; (3) a dismembered ophiolitic series formed by slices of metagabbros and metabasalts separated by ultramafic lenses (the Masherbrum Greenstone Complex). The occurrence of such Cambro-Ordovician series overlying a Precambrian basement in south-eastern Karakoram similar to the south-western Karakoram shows that the Karakoram constitutes a continuous tectonic block. The petrology and geochemistry of the Masherbrum Greenstone Complex (mineral chemistry, major and trace element and Sr-Nd isotopic data) are indicative of a supra-subductive environment. The presence of LREE-enriched calc-alkaline rocks 〚(La/Yb) N = 4.4-5.6; (Nb/La) N = 0.2-0.3; ɛNd 565 = 5.1-7.1〛 and LREE-depleted tholeiitic rocks 〚(La/Yb) N = 0.5-1.3; (Nb/La) N = 0.6-0.9; ɛNd 565 = 5.6-7.8〛 are consistent with arc and back-arc settings, respectively. A high-Mg andesitic dolerite and an OIB-type metabasalt, with lower ɛNd ratios (ɛNd 565 = 0.5 and 4.5) are in accordance with source heterogeneity beneath the arc. The Masherbrum Greenstone Complex, along with other Cambro-Ordovician central-eastern volcanic series give evidence of a tectonic situation governed by micro-plate convergent-divergent systems with occurrence of arc - back-arc settings during the Lower Palaeozoic, comparable to that of the current SW Pacific area.

Published
2002
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