Organic matter in sediments of a tropical and upwelling influenced region of the Brazilian continental margin (Campos Basin, Rio de Janeiro)

2018 ◽  
Vol 120 ◽  
pp. 86-98 ◽  
Author(s):  
Lívia G.M.S. Cordeiro ◽  
Angela L.R. Wagener ◽  
Renato S. Carreira
Zootaxa ◽  
2009 ◽  
Vol 2081 (1) ◽  
pp. 31-45 ◽  
Author(s):  
MARIA CRISTINA DA SILVA ◽  
FRANCISCO JOSÉ VICTOR DE CASTRO ◽  
MARIANA DA FONSECA CAVALCANTI ◽  
VERÔNICA DA FONSÊCA-GENEVOIS

In deep-sea sediments from Campos Basin two new species of Spirinia were found. Spirinia lara sp. n. is mainly characterized by the presence of paired somatic papillae linked to gland cells and distributed all over the body while Spirinia sophia sp. n. possesses an irregular distribution of these glandular somatic papillae.


2013 ◽  
Vol 118 (4) ◽  
pp. 1484-1494 ◽  
Author(s):  
M. S. Krishna ◽  
S. A. Naidu ◽  
Ch. V. Subbaiah ◽  
V. V. S. S. Sarma ◽  
N. P. C. Reddy

2013 ◽  
Vol 85 (4) ◽  
pp. 1289-1301 ◽  
Author(s):  
ESTEFAN M. DA FONSECA ◽  
JOSE A. BAPTISTA NETO ◽  
JOHN MCALISTER ◽  
BERNARD SMITH ◽  
MARCOS A. FERNANDEZ ◽  
...  

One of the main results of the processes related to urbanization is the contamination of the adjacent water bodies. Inserted in this context, the Rodrigo de Freitas lagoon is situated in the south zone of the city of Rio de Janeiro. This ecosystem receives several inputs containing all sorts of pollutants, including heavy metals. The present work aimed to study the partitioning of heavy metals in the sediments of Rodrigo de Freitas and the influence of organic matter in this fractionation dynamic. The results of these analyses presented the contents of organic matter as an important metal-capturing agent. Fractionation of organic matter resulted in a predominance of humine. Heavy metal partitioning showed that the metals bound by the water-soluble phase have no significant concentrations. Special features such as, reducing sediment, high levels of organic matter and fine grain size have transformed this ecosystem in an effective deposit of pollutants, where heavy metals are not available in easily reactive fractions.


2015 ◽  
Vol 45 (3) ◽  
pp. 415-429 ◽  
Author(s):  
Ana Carolina Tavares ◽  
Leonardo Borghi ◽  
Patrick Corbett ◽  
Jane Nobre-Lopes ◽  
Raphael Câmara

Lacustrine carbonate rocks form important hydrocarbon accumulations along the Brazilian continental margin, some of which are contained in oil fields in which coquinas are one of the main reservoirs (viz. Campos Basin). The complexity and heterogeneity of these deposits make them a challenge in terms of reservoir description. For the necessary classification and paleoenvironmental interpretation of the coquinas, it is essential to evaluate many aspects including biological (such as carbonate productivity), sedimentological (energy regime in the depositional environment, transport of bioclasts, terrigenous supply), taphonomic (fragmentation of shells, abrasion) and diagenetic processes. The facies analysis applied in this study is considered a more appropriate classification approach to understand these coquinas, since it is more flexible and comprehensive than the existing classifications for carbonate rocks. The material investigated here consists of rock samples of the coquinas from the Atol Quarry of the Morro do Chaves Formation (Barremian/Aptian), Sergipe-Alagoas Basin. These rocks that crop out in the Atol quarry complex can be considered as a case study for similar coquinas reservoirs found in the Brazilian continental margin basins. Six sedimentary facies were described, using the main taphonomic (fragmentation of shells) and compositional (presence of micrite and siliciclastic matrix) features as a diagnostic criteria. Two carbonate facies, two mixed carbonate-siliciclastic facies and two siliciclastic facies (mudstones) were identified. From the facies succession, combined with a review of the literature on the subject, the following depositional paleoenvironments were defined: high-energy lake platform, lacustrine delta in a high-energy lake platform and lake-centre. In this paper, a new facies model for the studied coquinas succession is proposed.


2003 ◽  
Vol 63 (2) ◽  
pp. 269-281 ◽  
Author(s):  
A. L. Henriques-Oliveira ◽  
J. L. Nessimian ◽  
L. F. M. Dorvillé

Chironomids larvae are frequently one of the most abundant and diverse groups of insects in several kinds of aquatic environments. Also, they play a major role in the aquatic food webs, representing a major link among producers and secondary consumers. This work investigates the feeding behavior of the chironomid larvae present in the Rio da Fazenda, situated in the Parque Nacional da Tijuca, Rio de Janeiro, Brazil, between August 1994 and May 1995. Algae, fungi, pollen, leaf and wood fragments, animal remains, detritus and silt were the main gut contents found in the larvae studied. The main food item ingested by the larvae was detritus, except for the Stenochironomus whose main food source was leaf and wood fragments. Tanypodinae exhibited a large quantity of animal remains of several kinds in the diet. During the period studied it was observed that the diet of 16 genera (out of 24 studied) varied. Tanypodinae had mainly coarse particulate organic matter (> 1 mm) in the gut contents, while Chironominae and Orthocladiinae had fine particulate organic matter (< 1 mm).


2019 ◽  
Vol 4 (2) ◽  
pp. 159-173 ◽  
Author(s):  
Lazaro Laut ◽  
Maria Virgina Alves Martins ◽  
Pierre Belart ◽  
Maria Lucia Lorini ◽  
Iara Clemente ◽  
...  

Bottom sediment is a natural trap for organic matter and different kinds of pollutants. The accumulation of large amount of organic matter gives rise to the eutrophication of the aquatic ecosystems. The analyses of the quantity and quality of the organic matter (biopolymers) help to determine the trophic status of coastal ecosystems. The Maricá-Guarapina Lagoon System (MGLS) is located in Rio de Janeiro and is composed by four connected lagoons: Maricá, Barra, Padre and Guarapina. It has been suffering impacts due to the intense and uncontrolled property speculation. Based on this problem, this study aimed to characterize the organic matter (OM) amount and quality in sediments and the relation with the impacted areas in this lagoon system. The collected sediment samples were analyzed for geochemical data combined with grain size and physical-chemical environmental parameters of the bottom water. Statistical results evidenced that the sedimentary environment of the MGLS is heterogenous. The organic matter supplied to the MGLS is provided from different sources but the autochthonous contribution (phytoplanktonic productivity and vegetal detritus from the mangrove fringe) prevails. The anthropogenic contribution was more evident in Padre Lagoon, where the sediments had relatively low TOC contents (0.1-0.8%). The MGLS is accumulating mainly aged organic matter. The most impacted zones were found in Guarapina, Barra and Maricá lagoons, in bottoms of fine-grained sediments, with relatively high TOC and labile biopolymeric compounds (proteins, carbohydrates and lipids) contents, which should evolve into an ever-increasing stage of eutrophication. COMPOSTOS ORGÂNICOS USADOS COMO INDICADORES DA QUALIDADE AMBIENTAL SEDIMENTAR DO SISTEMA LAGUNAR MARICÁ-GUARAPINA (SE DO BRASIL)ResumoO sedimento de fundo constitui uma armadilha natural para a matéria orgânica e diferentes tipos de poluentes. O acúmulo de grande quantidade de matéria orgânica dá origem à eutrofização dos ecossistemas aquáticos. Estimativas de quantidade e qualidade da matéria orgânica (biopolímeros) podem ajudar a determinar o estado trófico dos ecossistemas costeiros. O Sistema Lagunar de Maricá-Guarapina (MGLS), localizado no Estado do Rio de Janeiro (SE do Brasil), é composto por quatro lagunas interconectadas: Maricá, Barra, Padre e Guarapina. Este sistema tem sofrido impactos devido à intensa e descontrolada especulação imobiliária. Neste contexto, este estudo teve como objetivo caracterizar a quantidade e qualidade de matéria orgânica (MO) dos sedimentos do MGLS. Foram obtidos dados geoquímicos e confrontados com resultados granulométricos em amostras de sedimentos coletados em 22 estações de amostragem e analisados parâmetros físico-químicos da água. Os resultados estatísticos evidenciaram que o ambiente sedimentar do MGLS é heterogêneo. Este sistema recebe matéria orgânica de diferentes fontes, sendo, porém, prevalecente a contribuição autóctone (produtividade fitoplanctônica e detritos vegetais dos manguezais existentes na região). A contribuição antropogênica de matéria orgânica foi mais evidente na Lagoa do Padre, onde os sedimentos apresentaram teores de COT relativamente baixos (0,1-0,8%). As zonas mais impactadas foram encontradas em fundos de sedimentos finos, com teores relativamente elevados de COT e de compostos biopoliméricos lábeis (proteínas, carboidratos e lipídios), nas lagunas de Guarapina, Barra e Maricá. Os resultados obtidos revelam também que o MGLS está acumulando principalmente matéria orgânica envelhecida e permitem prever que as referidas áreas podem evoluir para um estágio de cada vez maior grau de eutrofização.Palavras-chave: Lagunas Costeiras Tropicais. Biopolímeros. Eutrofização. Dinâmica Sedimentar.


Sign in / Sign up

Export Citation Format

Share Document