Erratum to “spatial and temporal variation of benthic marine algae at the Cabo Frio upwelling region Rio de Janeiro, Brazil” [Aquat. Bot. 52 (1996) 283–299] (original) (raw)
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Marine Ecology Progress Series, 2014
To determine whether shifts occurred in the food web associated with upwelling at the Brazilian western boundary South Atlantic Central Water (SACW), we measured isotopic composition (δ 15 N and δ 13 C) of 38 fish and 3 squid species from the Cabo Frio food web. Sampling was performed during the austral summer upwelling period (February 2002) and the austral winter non-upwelling period (July 2001). Mean lipid-corrected δ 13 C (δ 13 C cor) values ranged from −20.17 to −15.02 ‰, and mean δ 15 N ranged from 10.28 to 16.08 ‰. An analysis of covariance performed using length as a covariate provided evidence of seasonal effects on the mean fish δ 13 C cor and δ 15 N, with higher values during the non-upwelling period than during the upwelling period. These effects are most likely related to biophysical processes that occurred 1 to 6 mo earlier. The data furnish circumstantial evidence of a link between the dynamics of the SACW and the trophic structure of Cabo Frio. The trophic level of the species of fish and squids ranged between the theoretical trophic levels of 3.6 and 5.1, but there were no discrete steps, rather a continuous gradient in isotopic values. This suggests that these food webs are unstructured and the component species have mixed diets.
Geographic variation in reef-fish assemblages along the Brazilian coast
Global Ecology and Biogeography, 2001
The species composition of reef-fish assemblages from nine Brazilian major coastal sites and four oceanic islands are compared. Canonical correspondence analysis (CCA) was utilized to identify groups of sites based on similarity of composition, and to correlate environmental trends with such groups. Five distinct groups of sites were recognized: (1) the South and South-eastern coastal reefs (from Guarapari Islands to Santa Catarina, the southernmost Brazilian reefs); (2) the North-eastern coast (extending from the Manuel Luis Reefs to Abrolhos Archipelago); (3) Trindade Island; (4) Fernando de Noronha and Atol das Rocas; and (5) St Paul's Rocks. Water temperature, coral richness, distance from mainland, primary production and shelf width strongly correlated with the diversity and composition of the reef sites.
The coastal upwelling off Cabo Frio (SE Brazilian coast, SEBC) represents an exception to the world's oceans since the majority of the upwelling areas are located in eastern boundary current systems. Cabo Frio represents an interesting area for investigation due to its tight physical-biological interaction and the importance of the region as a major fishery area in the SEBC. We analyzed a suite of lipid biomarkers to apportion the main sources of organic matter in surface sediments of the continental shelf off Cabo Frio, comparing the area to non-upwelling regions off the SEBC (shelf break off Cabo Frio and continental shelf off Ubatuba). During spring and summer (the upwelling period), diatoms are probably the major sources of polyunsaturated fatty acids (PUFAs) and C 28 sterols in surface sediments from Cabo Frio continental shelf. Sediments sampled in winter showed, in contrast, lower relative abundance of PUFAs and higher stanol/stenol ratio values. In deeper regions off Cabo Frio, elevated concentrations of alkenones, 24-methylcholest-5,22E-dien-3b-ol and 24-ethylcholest-5-en-3b-ol during the spring may be produced by prymnesiophytes or cryptophytes and cyanobacteria, respectively. In Ubatuba, the C 27 and C 28 sterols are likely derived from omnivorous salps and nanoflagellates. At non-upwelling areas, despite the increase in biomarker concentrations during spring and summer, lower concentrations of PUFAs, phytol and algal sterols than in shelf areas off Cabo Frio suggest the importance of the upwelling system to the rapid transfer of organic carbon to surface sediments. Our results suggest that spatial and temporal variability in organic matter production and deposition merits consideration for constraining the carbon budgets in the coastal region off Cabo Frio.
Organic Geochemistry, 2008
The coastal upwelling off Cabo Frio (SE Brazilian coast, SEBC) represents an exception to the world's oceans since the majority of the upwelling areas are located in eastern boundary current systems. Cabo Frio represents an interesting area for investigation due to its tight physical-biological interaction and the importance of the region as a major fishery area in the SEBC. We analyzed a suite of lipid biomarkers to apportion the main sources of organic matter in surface sediments of the continental shelf off Cabo Frio, comparing the area to non-upwelling regions off the SEBC (shelf break off Cabo Frio and continental shelf off Ubatuba). During spring and summer (the upwelling period), diatoms are probably the major sources of polyunsaturated fatty acids (PUFAs) and C 28 sterols in surface sediments from Cabo Frio continental shelf. Sediments sampled in winter showed, in contrast, lower relative abundance of PUFAs and higher stanol/stenol ratio values. In deeper regions off Cabo Frio, elevated concentrations of alkenones, 24-methylcholest-5,22E-dien-3b-ol and 24-ethylcholest-5-en-3b-ol during the spring may be produced by prymnesiophytes or cryptophytes and cyanobacteria, respectively. In Ubatuba, the C 27 and C 28 sterols are likely derived from omnivorous salps and nanoflagellates. At non-upwelling areas, despite the increase in biomarker concentrations during spring and summer, lower concentrations of PUFAs, phytol and algal sterols than in shelf areas off Cabo Frio suggest the importance of the upwelling system to the rapid transfer of organic carbon to surface sediments. Our results suggest that spatial and temporal variability in organic matter production and deposition merits consideration for constraining the carbon budgets in the coastal region off Cabo Frio.
Continental Shelf Research, 2014
The present work provided monthly monitoring of sedimentary organic matter composition, benthic bacteria and macrofauna during 13 months in a permanent station in the inner shelf ($ 40 m depth) off Ubatuba, SE Brazil. Sediment organic matter compounds evaluated in the present study included the total organic matter, lipid biomarkers and phytopigments. The organic matter presented a complex distribution, typical of inner shelves, intimately related to coastal dynamics that drive the buildup (high primary production) or removal (high energy events) of labile organic matter from the sediments. Lipid biomarker composition revealed that particulate organic matter was mainly derived from autochthonous sources, such as plankton, sediment bacteria and benthic metazoan fauna. The benthic dynamics off Ubatuba coast is highly influenced by the intrusion of the South Atlantic Central Water (SACW) onto the shelf, bringing nutrients up to the euphotic zone and stimulating new phytoplanktonic production. This enhances the flux of organic matter to the bottom increasing benthic biota density. The results obtained in the present study suggest a strong and complex benthic-pelagic coupling, influenced by mesoscale oceanographic events (i.e. intrusion of SACW), and by local events (cold fronts) influencing the benthic system through the remobilization of sediments.
First Evidence of a Nursery Habitat for Juvenile Gag in the Southern Gulf of Mexico
Transactions of the American Fisheries Society, 2006
Information on a nursery area for juvenile gag Mycteroperca microlepis in the southern Gulf of Mexico is offered for the first time in this study. A total of 817 gags that ranged in size from 1.5 to 34.5 cm standard length (SL) were captured with a small trawl net from January to December 2001 in a shallow sea grass bed (mainly turtle grass Thalassia testudinum, manatee grass Syringodium filiforme, and shoal grass Halodule wrightii). The gag biomass in the swept area was 217 6 74 kg/km 2 (mean 6 SD) with a density of 48,393 6 125 fish/km 2 . Peak ingress of gag was observed from March to May, when newly settled organisms (range, 1.5-2.8 cm SL; n ¼ 28) and the smallest young of the year (age 0; 3.2-4.9 cm SL; n ¼ 72) were caught. After settlement, juveniles reached maximum abundance by July (n ¼ 186) with a size range of 8.0-18.2 cm SL and then began to leave the nursery area in September. The monthly occurrence of newly settled gag, lengthfrequency analysis, and otolith aging indicate that age-0 gag (range, 1.5-19.5 cm SL; n ¼ 756) were present in this nursery area from March to December 2001 as a single discrete cohort. These results suggest that settlement is discontinuous for gag in this region. Back-calculated hatching dates, estimated from otoliths of early juveniles captured in April (3.5-5.2 cm SL;
2014
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em EcologiaA comunidade mesozooplanctônica foi analisada em relação à estrutura de tamanho do fitoplâncton, às massas d' água e aos processos oceanográficos da plataforma continental de Santa Catarina. Arrastos verticais de zooplâncton (200 µm), amostras de água para nutrientes, clorofila e quantificação do fitoplâncton, registros de temperatura, salinidade e fluorescência (Rosette/CTD) foram obtidos no início do verão (dezembro/2010). Transectos perpendiculares à Baía da Babitonga (BB-26°S), Rio Itajaí (IR-27°S), Santa Catarina island (SCI-28°S) e Cabo de Santa Marta (CSM-28.5°S) foram conduzidos pelo NHo Cruzeiro do Sul. No CSM, a intrusão da Água Central do Atlântico Sul (ACAS) próximo à superfície coincidiu com altas concentrações de clorofila-a (2 mg . m-3) e biomassa zooplanctônica (1.40 mg.m-3) caracterizando o início da ressurgência de verão. O plânct...
Continental Shelf Research, 2008
The physical aspects of the Subtropical Shelf Front (STSF) for the Southwest Atlantic Continental Shelf were previously described. However, only scarce data on the biology of the front is available in the literature. The main goal of this paper is to describe the physical, chemical and biological properties of the STSF found in winter 2003 and summer 2004. A cross-section was established at the historically determined location of the STSF. Nine stations were sampled in winter and seven in summer. Each section included a series of conductivity-temperature-depth (CTD) stations where water samples from selected depths were filtered for nutrient determination. Surface samples were taken for chlorophyll a (Chl-a) determination and plankton net tows carried out above and below the pycnocline. Results revealed that winter was marked by an inner-shelf salinity front and that the STSF was located on the mid-shelf. The low salinity waters in the inner-shelf indicated a strong influence of freshwater, with high silicate (72 mM), suspended matter (45 mg l À1 ), phosphate (2.70 mM) and low nitrate (1.0 mM) levels. Total dissolved nitrogen was relatively high (22.98 mM), probably due to the elevated levels of organic compound contribution close to the continental margin. Surface Chl-a concentration decreased from coastal well-mixed waters, where values up to 8.0 mg m À3 were registered, to offshore waters. Towards the open ocean, high subsurface nutrients values were observed, probably associated to South Atlantic Central Waters (SACW). Zooplankton and ichthyoplankton abundance followed the same trend; three different groups associated to the inner-, mid-and outer-shelf region were identified. During summer, diluted waters extended over the shelf to join the STSF in the upper layer; the concentration of inorganic nutrients decreased in shallow waters; however, high values were observed between 40 and 60 m and in deep offshore waters. Surface Chl-a ranged 0.07-1.5 mg m À3 ; winter levels were higher. Three groups of zoo and ichthyoplankton, separated by the STSF, were also identified. Results of the study performed suggest that the influence of freshwater was stronger during winter and that abundance distribution of Chl-a, copepods and ichthyoplankton was related to the Plata Plume Waters (PPW), rather than to the presence of the STSF. During summer, when the presence of freshwater decreases, plankton interactions seem to take place in the STSF.