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- ItemSurf zone diatoms: a review of the drivers, patterns and role in sandy beaches food chains(ELSEVIER, 2014) Odebrecht, Clarisse; Preez, Derek Richard du; Abreu, Paulo Cesar Oliveira Vergne de; Campbell, Eileen ElaineThe accumulation of high biomass of diatoms in the surf zone is a characteristic feature of some sandy beaches where the wave energy is sufficiently high. A few species of diatoms, called surf diatoms, thrive in this harsh environment. The main processes driving the spatial and temporal distribution of surf diatoms as well as their standing biomass and growth were described twenty to thirty years ago based on studies conducted on the western coast of the United States of America and South African beaches. Since then, over fifty locations around the world have been reported to have surf diatom accumulations with most (three-quarters) of these being in the southern hemisphere. Their occurrence is controlled by physical and chemical factors, including wave energy, beach slope and length, water circulation patterns in the surf zone and the availability of nutrients to sustain the high biomass. The main forces driving the patterns of temporal variability of surf diatom accumulations are meteorological. In the short term (hours), the action of wind stress and wave energy controls the diatom accumulation. In the intermediate time scale (weeks to months), seasonal onshore winds of sufficient strength, as well as storm events are important. Furthermore, anthropogenic disturbances that influence the beach ecosystem as well as large-scale events, such as the El Niño Southern Oscillation, may lead to significant changes in surf diatom populations in the long term (inter-annual). Surf diatoms form the base of a short and very productive food chain in the inshore of the sandy beaches where they occur. However, the role of surf diatoms in the microbial food web is not clear and deserves further studies.
- ItemA análise da cadeia produtiva dos catados como subsídio à gestão costeira: as ameaças ao trabalho das mulheres nos manguezais e estuários no Brasil(2012) Walter, Tatiana; Wilkinson, John; Silva, Angelus Giuseppe Pereira daO presente artigo apresenta a aplicação do aporte analítico dos sistemas agroalimentares associado à Sociologia Econômica na análise de questões afeitas à pesca artesanal, tendo como perspectiva uma abordagem sistêmica e territorializada, centrais à gestão costeira. Para tal, analisou a cadeia produtiva dos catados oriundos da mariscagem em oito municípios litorâneos da Bahia por meio de um aporte teórico-analítico diversificado que permitiu a compreensão dos diversos fenômenos que afetam a atividade das mulheres na produção de catados, incluindo aqueles oriundos da dinâmica territorial. A coleta de dados concatenou a análise de informações pretéritas com pesquisa-observante e realização de entrevistas semiestruturadas, no período de julho de 2009 a junho de 2010, envolvendo informações sobre 94 comunidades pesqueiras. Os resultados denotam a complexidade em torno das estratégias de comercialização, ainda que os fluxos de produção estejam predominantemente circunscritos à região. Verificou-se que, considerando as demais atribuições das mulheres, tanto na elaboração de outros produtos pesqueiros como frente aos afazeres domésticos, tem-se na degradação dos manguezais um processo que concatena sobrecarga de trabalho com perda de produção e renda. Degradação esta oriunda da expansão urbana, do turismo e da poluição relacionada à maricultura e à atividade petrolífera. Dois outros fatores são importantes entraves nesta cadeia produtiva: as exigências sanitárias que discriminam as práticas domésticas em torno do beneficiamento dos catados e a falta de saúde laboral associada à ausência de mecanismos de seguridade social. Em relação aos resultados obtidos, este conjunto de fatores representa uma ameaça às marisqueiras, no que tange à manutenção de sua reprodução social. Conclui-se, ainda, que o aporte teórico-analítico adotado é adequado à análise das questões afetas à atividade pesqueira, especialmente por contemplar uma abordagem capaz de inseri-la como parte da gestão costeira.
- ItemThe last 25,000 years in the Eastern Plateau of Southern Brazil according to Alpes de São Francisco record(Elsevier, 2010) Leonhardt, Adriana; Lorscheitter, Maria LuisaThe palaeoenvironmental history has been studied based on palynology of a sedimentary profile from the Alpes de São Francisco bog (29290 3500S, 50370 1800W), São Francisco de Paula municipality, Rio Grande do Sul eastern Plateau, extreme Southern Brazil. The results indicate a regional cold and dry climate between 25,000 and 12,500 yr BP, interpreted from the grassland vegetation, forest taxa were present in refuges and the shallow local lake began to fill in. Climatic conditions became more aride after 16,000 yr BP, when grassland became rare. From 12,500 yr BP onwards, the climate began to change and at 11,000–9700 yr BP a warm and moist climate permitted the slight migration of pioneer arboreal taxa from refuges and locally a marsh formation. Between 9700 and 6500 yr BP a warm and dry climate resulted in reduction of grassland, confined the forest in refuges, dried out the marsh. The gradual increase of humidity between 6500 and 4000 yr BP allowed migration of forests from refuges and a bog developed. Between 4000 and 2000 yr BP Araucaria forest spread, indicating moister climate. The local bog expanded. From 2000 yr BP onwards, humid but warmer climate seems to result in a lower reproductive capacity of Araucaria forest taxa limiting its expansion. The bog reached the present-day in a decline condition. The results are compared to previous records from Southern Brazil highlands and some places from Argentina in order to better elucidate the climatic and vegetational history of these important South America areas during the late Quaternary.
- ItemRetention time generates short-term phytoplankton blooms in a shallow microtidal subtropical estuary(Elsevier, 2015) Odebrecht, Clarisse; Abreu, Paulo Cesar Oliveira Vergne de; Carstensen, JacobIn this study it was hypothesised that increasing water retention time promotes phytoplankton blooms in the shallow microtidal Patos Lagoon estuary (PLE). This hypothesis was tested using salinity variation as a proxy of water retention time and chlorophyll a for phytoplankton biomass. Submersible sensors fixed at 5 m depth near the mouth of PLE continuously measured water temperature, salinity and pigments fluorescence (calibrated to chlorophyll a) between March 2010 and 12th of December 2011, with some gaps. Salinity variations were used to separate alternating patterns of outflow of lagoon water (salinity <8; 46% of the time) and inflow of marine water (salinity >24; 35% of the time). The two transition phases represented a rapid change from lagoon water outflow to marine water inflow and a more gradually declining salinity between the dominating inflow and outflow conditions. During the latter of these, a significant chlorophyll a increase relative to that expected from a linear mixing relationship was observed at intermediate salinities (10e20). The increase in chlorophyll a was positively related to the duration of the prior coastal water inflow in the PLE. Moreover, chlorophyll a increase was significantly higher during austral spring-summer than autumn-winter, probably due to higher light and nutrient availability in the former. Moreover, the retention time process operating on time scales of days influences the long-term phytoplankton variability in this ecosystem. Comparing these results with monthly data from a nearby long-term water quality monitoring station (1993e2011) support the hypothesis that chlorophyll a accumulations occur after marine inflow events, whereas phytoplankton does not accumulate during high water outflow, when the water residence time is short. These results suggest that changing hydrological pattern is the most important mechanism underlying phytoplankton blooms in the PLE.
- ItemThe productivity history in the Southwestern Atlantic as inferred from coccolitophore record fot the last 130 kyr(2013) Leonhardt, Adriana; Toledo, Felipe Antonio de Lima; Coimbra, João CarlosIn this work, fossil assemblages of coccolithophorids, oxygen stable isotopes (Globigerinoides ruber), and radiocarbon dating were used as proxies. The sediment core, obtained on the slope of Campos Basin, was analyzed, comprising the last 130 kyr. The results show that placolith-bearing taxa, such as Gephyrocapsa spp. and Emiliania huxleyi, as well as Florisphaera profunda, which inhabits the lower photic zone, dominated the assemblage during the whole study interval. Over the past 130 kyr, there was a relationship between productivity (based on N ratio) and climate cyclicity. In a general way, it can be said that sensu stricto interglacial stages (MIS 5e and the Holocene) showed low productivity, while the others (MIS 5d-a, 4, 3 and 2) had large fl uctuations. During interglacial-like conditions, a northward shift in the Intertropical Convergence Zone position would take place, along with a weakening of the NE winds associated with the Southern Atlantic Subtropical High and a weakening of the Brazil Current, leading to the maintenance of the water stratifi cation. On the other hand, during glacial-like conditions, the inverse conditions would be favorable to a shallower nutricline, increasing productivity in surface waters. Maximum productivity is achieved between 14-6.5 ky (during deglaciation), which could be a refl ection of the events of the Last Glacial Maximum.
- ItemPólen de Magnoliopsida (Asteridae) e Liliopsida do perfil sedimentar de uma turfeira em São Francisco de Paula, Planalto Leste do Rio Grande do Sul, Sul do Brasil(2010) Leonhardt, Adriana; Lorscheitter, Maria Luisa(Magnoliopsida (Asteridae) and Liliopsida pollen of the sedimentary profile of a bog, São Francisco de Paula, Eastern Plateau of Rio Grande do Sul, Southern Brazil). This paper aims to provide data for paleopalynological research progress in southern Brazil by increasing the knowledge about the Quaternary in the region. Therefore, the palynological analysis of a sedimentary profile of a bog of Rio Grande do Sul Eastern Plateau was made and the Angiospermae pollen (Asteridae, Alismatidae, Commelinidae and Liliidae) are presented. The profile is 286 cm long, corresponding approximately to the last 25,000 years. The chemical processing of the 22 samples obtained followed the standard methodology and the analysis was made by light microscopy. The photomicrographs are accompanied by concise morphological descriptions, including measurements of polar and equatorial axis and ecological data of the original sporophyte. Pollen corresponding to 21 Asteridae, one Alismatidae, four Commelinidae and three Liliidae were identified, beside three indeterminate pollens of Angiospermae.
- ItemThe contribution of diatoms to bioflocs lipid content and the performance of juvenile Litopenaeus vannamei (Boone, 1931) in a BFT culture system(Wiley Online Library, 2014) Machado, Tatiana Germano Martins; Odebrecht, Clarisse; Vaz, Luciano Jensen; D'Oca, Marcelo Gonçalves Montes; Wasielesky Junior, Wilson Francisco BrittoThis study aimed to evaluate the contribution ofthree diatom species on the lipid content of bio-flocs, their permanence on the bioflocs and influ-ence on the growth performance of juvenileshrimps. Juveniles of Litopenaeus vannamei werereared (30 days; three replicates per treatment)in biofloc systems inoculated with diatomsAmphora coffeaeformis (A), Cylindrotheca closterium(C), Conticribra weissflogii (W), or biofloc only(BF, chlorophycean rich). Water quality parame-ters were monitored daily and the microbiota ondays 1, 10, 20 and 30. The lipid content andfatty acid profiles of bioflocs were analyzed at theend of the experiment. Shrimp survival rate(99%) at treatment A was significantly higherthan at BF. The bioflocs in A treatment pre-sented the highest lipid content, differing signifi-cantly from BF and W. The content of EPA(20:5) (n-3) was significantly higher in A andlower in BF, while linoleic acid (18:2) (n-6) wassignificantly higher in BF. The results indicatethat high cell density of diatoms can be success-fully maintained with silicate addition in bioflocsystems and that the pennate A. coffeaeformis andthe centric C. weissflogii are potentially better sui-ted than the pennate C. closterium as food sup-plements for shrimp diets in biofloc nurseriessystem.
- ItemDinoflagelados (Peridiniales, Prorocentrales) do microplâncton na plataforma continental e talude do extremo sul do Brasil (inverno 2005, verão 2007)(2011) Islabão, Carolina Antuarte; Odebrecht, ClarisseThis study aimed at identifying morpho-species of microplankton dinoflagellates (> 20 μm) of the order Peridiniales and Prorocentrales off Santa Marta Grande Cape, CSMG (SC, 28º 40’ S) and Albardão-Chui, AC ( r S, 34º 40’ S) during oceanographic cruises conducted in winter 2005 and summer 2007. Plankton samples were obtained by vertical net (mesh size 20 μm) hauls preserved with formaldehyde 4% and analyzed using the inverted microscope equipped with a digital camera. The identification of Peridiniales species was based on the number and morphology of thecal plates enhanced with Calco Fluor White M r 2 whenever necessary and the identification of Prorocentrales was based on cell size, shape, presence of apical processes, pore pattern and marks at the intercalary band. We identified 25 species, including Protoperidinium (11), Prorocentrum (6), Corythodinium (3), Podolampas (2), Oxytoxum (2) and Heterocapsa (1). Prorocentrum species were widely distributed on the continental shelf of southern Brazil, while Peridiniales species were mainly found off Albardão-Chui during winter, especially under the influence of the plume of La Plata River. Oxytoxum milneri was the first time recorded in southern Brazil, while Protoperidinium cassum var. cassum , P. curtipes and Heterocapsa triquetra , were first registered in Brazil.
- ItemEffects of shrimp pond water on phytoplankton: importance of salinity and trophic status of the receiving environment(2014) Cardozo, Alessandro Pereira; Odebrecht, ClarisseAquaculture generates a large load of effluents richin organic matter and nutrients that may be intro-duced into the environment. This study aimed toassess in a microcosm experiment, the effect ofshrimp pond water mixed with Patos Lagoon estuarywater on phytoplankton chlorophyll a and primaryproduction, simulating two salinities. Chlorophyll a,dissolved inorganic nutrients and primary produc-tion were measured in two experiments. In Harvest I,salinity of shrimp pond and environment water wassimilar, and chlorophyll a showed different trendsover time, according to the amount of nitrogen avail-able. In Harvest II, with different salinities and highnutrient concentrations in environment water, chlo-rophyll a levels showed a similar increasing trendover time in all mixtures. Net primary productionshowed differences among treatments in the firstsampling in Harvest I, but not in the second, whereasno differences were observed among treatments inHarvest II. We conclude that shrimp pond effluentcan lead to short-term variations in chlorophyll aand primary production levels, with similar salinities.Salinity differences result in lower chlorophyll a andprimary production values than expected accordingto the nutrient input. Differences in salinity can bean important management strategy to choose thebest harvest period.
- ItemLong-term changes of the phytoplankton community and biomass in the subtropical shallow Patos Lagoon Estuary, Brazil(2015) Haraguchi, Lumi; Carstensen, Jacob; Abreu, Paulo Cesar Oliveira Vergne de; Odebrecht, ClarisseSeasonal and interannual changes (1993e2012) of water temperature and transparency, river discharge, salinity, water quality properties, chlorophyll a (chl-a) and the carbon biomass of the main taxonomical phytoplankton groups were evaluated at a shallow station (~2 m) in the subtropical Patos Lagoon Estuary (PLE), Brazil. Large variations in salinity (0e35), due to a complex balance between Patos Lagoon outflow and oceanic inflows, affected significantly other water quality variables and phytoplankton dynamics, masking seasonal and interannual variability. Therefore, salinity effect was filtered out by means of a Generalized Additive Model (GAM). River discharge and salinity had a significant negative relation, with river discharge being highest and salinity lowest during July to October. Diatoms comprised the dominant phytoplankton group, contributing substantially to the seasonal cycle of chl-a showing higher values in austral spring/summer (September to April) and lowest in autumn/winter (May to August). PLE is a nutrient-rich estuary and the phytoplankton seasonal cycle was largely driven by light availability, with few exceptions in winter. Most variables exhibited large interannual variability. When varying salinity effect was accounted for, chl-a concentration and diatom biomass showed less irregularity over time, and significant increasing trends emerged for dinoflagellates and cyanobacteria. Long-term changes in phytoplankton and water quality were strongly related to variations in salinity, largely driven by freshwater discharge influenced by climatic variability, most pronounced for ENSO events. However, the significant increasing trend of the N:P ratio indicates that important environmental changes related to anthropogenic effects are undergoing, in addition to the hydrology in the PLE.