Saulo Lamounier - Academia.edu (original) (raw)

Uploads

Papers by Saulo Lamounier

Corais pétreos são formadores de recifes. Por secretarem carbonato de cálcio pela base de seus pó... more Corais pétreos são formadores de recifes. Por secretarem carbonato de cálcio pela base de seus pólipos, esses corais zooxantelados formam um exoesqueleto, composto geralmente por cristais de aragonita. Os padrões de crescimento coralinos variam desde a escala sazonal a centenária e podem ser caracterizados pela medida da taxa de crescimento, a variabilidade dos isótopos estáveis de oxigênio e carbono e pelas razões elementares Sr/Ca, Mg/Ca, U/Ca, Cd/Ca, Ra/Ca (entre outras) em seu esqueleto. Em um contexto global, os recifes cumprem importante papel como sumidouros de carbono atmosférico. Diante das evidências de um oceano mais quente na era moderna, a temperatura da superfície do mar (TSM) tem sido considerada um importante fator de controle da calcificação e crescimento coralino. Geralmente, a calcificação tende a aumentar com a elevação da TSM dentro de uma estreita faixa aceitável para o funcionamento pleno do metabolismo coralino. Neste trabalho, desenvolveu-se uma re-análise d...

Radiocarbon

ABSTRACTThe Abrolhos bank, in southern Bahia State (BA), is the largest coral reef system in the ... more ABSTRACTThe Abrolhos bank, in southern Bahia State (BA), is the largest coral reef system in the southwestern Atlantic. It is highly influenced by the Brazil Current (BC), since it is located in the continental shelf. By contrast, Todos os Santos Bay (TSB), in Salvador, capital of Bahia State (BA) has an important coral biodiversity, located in a bay inlet with restricted water circulation. Coral cores were collected in those sites and were analyzed for density band counting and by Th/U dating to estimate growth rates and age. In this work, we present 14C ages of some of these bands in order to evaluate the marine reservoir effect (MRE) to which the colonies were subjected during growth. It is the first study making use of coral skeleton samples for MRE determination for the Brazilian coast. ΔR was calculated to be –151±23 14C yr, while that for the TSB was –107±51 14C yr.

Biogeosciences, 2016

Recent Southern Hemisphere (SH) atmospheric circulation, predominantly driven by stratospheric oz... more Recent Southern Hemisphere (SH) atmospheric circulation, predominantly driven by stratospheric ozone depletion over Antarctica, has caused changes in climate across the extratropics. Here, we present evidence that the Brazilian coast (southwestern Atlantic) may have been impacted from both wind and sea-surface temperature changes derived from this process. Skeleton analysis of massive coral species living in shallow waters off Brazil are very sensitive to air–sea interactions, and seem to record this impact. Growth rates of Brazilian corals show a trend reversal that fits the ozone depletion evolution, confirming that ozone impacts are far reaching and potentially affect coastal ecosystems in tropical environments.

Theses / Tese de doutorado, 2015

Stony corals are forming reefs. By secreting calcium carbonate from the bottom of their polyps, t... more Stony corals are forming reefs. By secreting calcium carbonate from the bottom of their polyps, these zooxanthellae corals form an exoskeleton, usually composed of aragonite crystals. The coral growth patterns vary from seasonal to centennial scale and can be characterized by measuring the growth rate, the variability of the stable isotopes of oxygen and carbon, and the elemental ratios Sr/Ca, Mg/Ca, U/Ca, Cd/Ca, Ra/Ca (among others) in its skeleton. In a global context, reefs play a key role as atmospheric carbon sinks. Faced with the evidence of a warmer ocean in the modern era, the sea surface temperature (SST) has been considered an important control factor in calcification and coral growth. Generally, calcification tends to increase with increasing SST within a narrow acceptable range for the full functioning of coral metabolism. In this work, a reanalysis of the growth rates of sampled corals cores on the brazilian coast has developed (Salvador-Ba - Bahia de Todos os Santos, Abrolhos Marine National Park-Ba and Armação dos Búzios-RJ) employing a combination of growth bands (high and low density) aided by the luminescence method, and radioisotope dating of U and Th. The differences in time lines for the two methods varied from 1 year to the case Abrolhos to 7.4 years to Búzios (in specific sections of the core). Calcification variations were analyzed in the coral skeleton and interpreted by using ratios Sr/Ca and U/Ca (both proxies of TSM), climate series of AMO and PDO, and pelagic oceanic pH. We have identified a decrease in calcification rate exoskeleton time studied in Salvador sample of 0.4 g/cm2 and an increase in Abrolhos 0.4 g/cm2 and Búzios 0.3 g/cm2 except in the 1950s to the late 1980s and 1910 to the late 1930s, respectively. A X-ray microtomography was used for the determination of coralline micro-structures, wich are the most relevant parameters to the microporosity and anisotropy. To Abrolhos and Búzios, it was identified an increase in total porosity of the exoskeleton, especially at the beginning of 1940 until the end of the 1980s and between 1890-1930 respectively. It was noted a strong association between reduced calcification pattern with increasing porosity. The cores of Siderastrea stellata species collected in Abrolhos and Búzios showed high association of the reasons Sr/Ca and U/Ca with calcification rate, featuring a similar response to other authors to the Great Barrier in Australia (DE'ATH et al., 2009) and the central region of the Red Sea (CANTIN et al., 2010). Regarding the reasons Ba/Ca, Salvador and Abrolhos showed the variables that contributed to this increase as oil production and population growth forcings (economy) and SST (ocean). At Búzios, SST (ocean), oil production, population growth and NDVI forcings (economy). After the 1990s, the impact of economic factors, in addition to oceanic variables respond more significantly the increase on the ratio Ba/Ca in all places almost simultaneously on the Brazilian coast.

Dissertação de mestrado, 2009

O presente trabalho teve como objetivo estudar a meiofauna da Praia Rasa (Búzios-RJ), descrevend... more O presente trabalho teve como objetivo estudar a meiofauna da Praia Rasa (Búzios-RJ), descrevendo sua distribuição espaço-temporal e sua composição faunística em grupos taxonômicos superiores. Em razão da dominância do Filo Nematoda nesta praia, o presente trabalho também estudou sua distribuição espaço-temporal e de seus tipos tróficos. As amostragens da meiofauna e das variáveis ambientais foram realizadas mensalmente de novembro de 2006 a outubro de 2007, em duas zonas do perfil praial: ressurgência e saturação. Os resultados obtidos revelaram que a meiofauna da Praia Rasa foi composta por sete grandes grupos faunísticos (Nematoda, Turbellaria, Copepoda, Tardigrada, Polychaeta, Oligochaeta e Halacaroidea). A densidade média da meiofauna total esteve entre 8 e 4747,33 ind.10 cm-2, sendo que as menores densidades ocorreram nos meses de verão. Os Nematoda representaram, em média, mais de 90% da meiofauna encontrada na camada dos 10 cm superiores do sedimento de ambas as zonas estudadas. A densidade média dos Nematoda variou de 4,33 a 4669 ind.10 cm-2 durante o período estudado. Os tipos tróficos dos Nematoda foram estudados nos períodos úmido e seco, determinados a partir de dados meteorológicos locais. Os quatro tipos tróficos dos Nematoda foram encontrados na Praia Rasa: Comedores de Epistrato (Herbívoros), Detritívoros Não Seletivos, Detritívoros Seletivos e os Predadores/Onívoros. No período úmido, os Comedores de Epistrato (Herbívoros), foram mais abundantes, enquanto que no periodo seco, os Detritívoros Não Seletivos dominaram. A distribuição dos grupos tróficos foi diferenciada entre as zonas do perfil praial, sendo os Herbívoros mais abundantes na Zona de Ressurgência, os Detritívoros Não Seletivos e os Predadores/Onívoros em geral foram mais abundantes na Zona de Saturação. A diferença entre as zonas de Ressurgência e Saturação foi evidenciada pela temperatura do sedimento e pelo percentual de MOT no sedimento. A densidade dos Nematoda no sedimento esteve significativamente associada ao percentual de areia muito fina. As interações entre a meiofauna e as variáveis ambientais foram melhor explicadas pela granulometria, MOT, concentração em Clorofila a e a temperatura do sedimento.

Corais pétreos são formadores de recifes. Por secretarem carbonato de cálcio pela base de seus pó... more Corais pétreos são formadores de recifes. Por secretarem carbonato de cálcio pela base de seus pólipos, esses corais zooxantelados formam um exoesqueleto, composto geralmente por cristais de aragonita. Os padrões de crescimento coralinos variam desde a escala sazonal a centenária e podem ser caracterizados pela medida da taxa de crescimento, a variabilidade dos isótopos estáveis de oxigênio e carbono e pelas razões elementares Sr/Ca, Mg/Ca, U/Ca, Cd/Ca, Ra/Ca (entre outras) em seu esqueleto. Em um contexto global, os recifes cumprem importante papel como sumidouros de carbono atmosférico. Diante das evidências de um oceano mais quente na era moderna, a temperatura da superfície do mar (TSM) tem sido considerada um importante fator de controle da calcificação e crescimento coralino. Geralmente, a calcificação tende a aumentar com a elevação da TSM dentro de uma estreita faixa aceitável para o funcionamento pleno do metabolismo coralino. Neste trabalho, desenvolveu-se uma re-análise d...

Radiocarbon

ABSTRACTThe Abrolhos bank, in southern Bahia State (BA), is the largest coral reef system in the ... more ABSTRACTThe Abrolhos bank, in southern Bahia State (BA), is the largest coral reef system in the southwestern Atlantic. It is highly influenced by the Brazil Current (BC), since it is located in the continental shelf. By contrast, Todos os Santos Bay (TSB), in Salvador, capital of Bahia State (BA) has an important coral biodiversity, located in a bay inlet with restricted water circulation. Coral cores were collected in those sites and were analyzed for density band counting and by Th/U dating to estimate growth rates and age. In this work, we present 14C ages of some of these bands in order to evaluate the marine reservoir effect (MRE) to which the colonies were subjected during growth. It is the first study making use of coral skeleton samples for MRE determination for the Brazilian coast. ΔR was calculated to be –151±23 14C yr, while that for the TSB was –107±51 14C yr.

Biogeosciences, 2016

Recent Southern Hemisphere (SH) atmospheric circulation, predominantly driven by stratospheric oz... more Recent Southern Hemisphere (SH) atmospheric circulation, predominantly driven by stratospheric ozone depletion over Antarctica, has caused changes in climate across the extratropics. Here, we present evidence that the Brazilian coast (southwestern Atlantic) may have been impacted from both wind and sea-surface temperature changes derived from this process. Skeleton analysis of massive coral species living in shallow waters off Brazil are very sensitive to air–sea interactions, and seem to record this impact. Growth rates of Brazilian corals show a trend reversal that fits the ozone depletion evolution, confirming that ozone impacts are far reaching and potentially affect coastal ecosystems in tropical environments.

Theses / Tese de doutorado, 2015

Stony corals are forming reefs. By secreting calcium carbonate from the bottom of their polyps, t... more Stony corals are forming reefs. By secreting calcium carbonate from the bottom of their polyps, these zooxanthellae corals form an exoskeleton, usually composed of aragonite crystals. The coral growth patterns vary from seasonal to centennial scale and can be characterized by measuring the growth rate, the variability of the stable isotopes of oxygen and carbon, and the elemental ratios Sr/Ca, Mg/Ca, U/Ca, Cd/Ca, Ra/Ca (among others) in its skeleton. In a global context, reefs play a key role as atmospheric carbon sinks. Faced with the evidence of a warmer ocean in the modern era, the sea surface temperature (SST) has been considered an important control factor in calcification and coral growth. Generally, calcification tends to increase with increasing SST within a narrow acceptable range for the full functioning of coral metabolism. In this work, a reanalysis of the growth rates of sampled corals cores on the brazilian coast has developed (Salvador-Ba - Bahia de Todos os Santos, Abrolhos Marine National Park-Ba and Armação dos Búzios-RJ) employing a combination of growth bands (high and low density) aided by the luminescence method, and radioisotope dating of U and Th. The differences in time lines for the two methods varied from 1 year to the case Abrolhos to 7.4 years to Búzios (in specific sections of the core). Calcification variations were analyzed in the coral skeleton and interpreted by using ratios Sr/Ca and U/Ca (both proxies of TSM), climate series of AMO and PDO, and pelagic oceanic pH. We have identified a decrease in calcification rate exoskeleton time studied in Salvador sample of 0.4 g/cm2 and an increase in Abrolhos 0.4 g/cm2 and Búzios 0.3 g/cm2 except in the 1950s to the late 1980s and 1910 to the late 1930s, respectively. A X-ray microtomography was used for the determination of coralline micro-structures, wich are the most relevant parameters to the microporosity and anisotropy. To Abrolhos and Búzios, it was identified an increase in total porosity of the exoskeleton, especially at the beginning of 1940 until the end of the 1980s and between 1890-1930 respectively. It was noted a strong association between reduced calcification pattern with increasing porosity. The cores of Siderastrea stellata species collected in Abrolhos and Búzios showed high association of the reasons Sr/Ca and U/Ca with calcification rate, featuring a similar response to other authors to the Great Barrier in Australia (DE'ATH et al., 2009) and the central region of the Red Sea (CANTIN et al., 2010). Regarding the reasons Ba/Ca, Salvador and Abrolhos showed the variables that contributed to this increase as oil production and population growth forcings (economy) and SST (ocean). At Búzios, SST (ocean), oil production, population growth and NDVI forcings (economy). After the 1990s, the impact of economic factors, in addition to oceanic variables respond more significantly the increase on the ratio Ba/Ca in all places almost simultaneously on the Brazilian coast.

Dissertação de mestrado, 2009

O presente trabalho teve como objetivo estudar a meiofauna da Praia Rasa (Búzios-RJ), descrevend... more O presente trabalho teve como objetivo estudar a meiofauna da Praia Rasa (Búzios-RJ), descrevendo sua distribuição espaço-temporal e sua composição faunística em grupos taxonômicos superiores. Em razão da dominância do Filo Nematoda nesta praia, o presente trabalho também estudou sua distribuição espaço-temporal e de seus tipos tróficos. As amostragens da meiofauna e das variáveis ambientais foram realizadas mensalmente de novembro de 2006 a outubro de 2007, em duas zonas do perfil praial: ressurgência e saturação. Os resultados obtidos revelaram que a meiofauna da Praia Rasa foi composta por sete grandes grupos faunísticos (Nematoda, Turbellaria, Copepoda, Tardigrada, Polychaeta, Oligochaeta e Halacaroidea). A densidade média da meiofauna total esteve entre 8 e 4747,33 ind.10 cm-2, sendo que as menores densidades ocorreram nos meses de verão. Os Nematoda representaram, em média, mais de 90% da meiofauna encontrada na camada dos 10 cm superiores do sedimento de ambas as zonas estudadas. A densidade média dos Nematoda variou de 4,33 a 4669 ind.10 cm-2 durante o período estudado. Os tipos tróficos dos Nematoda foram estudados nos períodos úmido e seco, determinados a partir de dados meteorológicos locais. Os quatro tipos tróficos dos Nematoda foram encontrados na Praia Rasa: Comedores de Epistrato (Herbívoros), Detritívoros Não Seletivos, Detritívoros Seletivos e os Predadores/Onívoros. No período úmido, os Comedores de Epistrato (Herbívoros), foram mais abundantes, enquanto que no periodo seco, os Detritívoros Não Seletivos dominaram. A distribuição dos grupos tróficos foi diferenciada entre as zonas do perfil praial, sendo os Herbívoros mais abundantes na Zona de Ressurgência, os Detritívoros Não Seletivos e os Predadores/Onívoros em geral foram mais abundantes na Zona de Saturação. A diferença entre as zonas de Ressurgência e Saturação foi evidenciada pela temperatura do sedimento e pelo percentual de MOT no sedimento. A densidade dos Nematoda no sedimento esteve significativamente associada ao percentual de areia muito fina. As interações entre a meiofauna e as variáveis ambientais foram melhor explicadas pela granulometria, MOT, concentração em Clorofila a e a temperatura do sedimento.