Papers by Helen Michelle Affe
Ocean and Coastal Research
Heringeriana
O semiárido brasileiro abrange áreas territoriais de oito Estados, desde o Nordeste até o norte d... more O semiárido brasileiro abrange áreas territoriais de oito Estados, desde o Nordeste até o norte de Minas Gerais, apresentando duas estações climáticas bem definidas durante o ano, uma chuvosa (dezembro a abril), e outra seca (maio a novembro). Durante o curto período chuvoso são formadas as lagoas temporárias, ecossistemas que abrigam uma flora bastante peculiar de macrófitas, adaptadas às condições de alta incidência luminosa e a sazonalidade pluviométrica da região. Associada a essa flora aquática, ocorre uma rica comunidade perifítica, que inclui, por exemplo, bactérias, fungos, pequenos metazoários e, especialmente, uma ampla diversidade de microalgas e cianobactérias. Nesse contexto, o presente trabalho foi desenvolvido com o objetivo de caracterizar a ficoflórula perifítica associada às macrófitas aquáticas de lagoas temporárias do semiárido baiano. A amostragem foi realizada em seis lagoas temporárias, localizadas ao longo da BA-052 (Estrada do Feijão), nos municípios de Ipi...
Rodriguésia
Scrippsiella acuminata is a species complex that can cause anoxic conditions in the water column ... more Scrippsiella acuminata is a species complex that can cause anoxic conditions in the water column during blooms. This study aimed to analyze the occurrence and distribution of Scrippsiella cf. acuminata along the estuarine gradient of Paraguaçu River, from bimonthly sampling (March 2018 to March 2019) performed at 12 sampling points. Environmental variables were measured in situ, and water samples were collected for analysis of dissolved inorganic nutrients and phytoplankton cell density. At each point, samples were collected for analysis of species composition and preserved with formaldehyde at a final concentration of 4%. S. cf. acuminata occurred throughout the estuarine gradient (salinity 0.1–38.9), except in July, coinciding with the lowest concentrations of dissolved inorganic nutrients. Cell density varied between 20 cel L-1 (January 2019) and 1.8 × 106 cell L-1 (March 2018); in the latter, the species bloomed under conditions of low salinity (5.7) and the highest dissolved in...
Heringeriana, 2022
A classe Euglenophyceae inclui flagelados unicelulares, autotróficos, mixotróficos e heterotrófic... more A classe Euglenophyceae inclui flagelados unicelulares, autotróficos, mixotróficos e heterotróficos, com morfologia variável e ampla distribuição em ecossistemas aquáticos continentais. O presente estudo teve como objetivo realizar um levantamento florístico de Euglenophyceae no Pantanal dos Marimbus, uma planície de inundação no bioma Caatinga, localizada no Parque Nacional da Chapada Diamantina. A região sofre inundações periódicas; as amostras foram realizadas a partir de uma grande área de lagoas interligadas durante maio e setembro de 2014, abril de 2015 e agosto de 2016, durante os períodos de menor precipitação antes da estação seca, quando as lagoas estavam isoladas umas das outras. Um total de 38 táxons foram identificados; 35 táxons são novas ocorrências para a Bahia, 25 para a região Nordeste e 2 para o Brasil. Os dados coletados aumentam nosso conhecimento sobre a distribuição deste grupo taxonômico nos ambientes aquáticos brasileiros e mostram a considerável diversidade...
Material suplementar do artigo "<b>Marine microalgae on the southern coast of Bahia, B... more Material suplementar do artigo "<b>Marine microalgae on the southern coast of Bahia, Brazil: c</b><b>omposition and new records of phytoplankton species"</b>, publicado na revista Rodriguésia<b><br></b>
Ocean and Coastal Research, 2021
Acta Botanica Malacitana, 2020
No presente trabalho apresentamos a caracterização da assembleia microfitoplanctônica na Baía de ... more No presente trabalho apresentamos a caracterização da assembleia microfitoplanctônica na Baía de Todos os Santos, considerando as condições abióticas locais, em uma curta série temporal, com o objetivo de ampliar o conhecimento sobre os padrões de composição, diversidade e distribuição do fitoplâncton na baía. Foram realizadas amostragens em três dias consecutivos, no mês de setembro 2016, em cinco pontos distribuídos no setor nordeste da baía. Foram medidos in situ a temperatura, salinidade, oxigênio dissolvido e transparência da água. Amostras foram coletadas utilizando-se garrafa de Van Dorn (1L), em subsuperfície (~0,5m), para análises quantitativas do microfitoplâncton. Amostras de 20mL foram coletadas por meio de arrastos horizontais de rede de plâncton de 20μm de abertura de malha, para análises de composição da comunidade. Os taxa foram identificados com base em literatura especializada e as análises quantitativas foram realizadas segundo o método de Utermöhl. As variáveis a...
&amp;lt;p&amp;gt;The Western Tropical Atlantic is a crucial region when it comes to under... more &amp;lt;p&amp;gt;The Western Tropical Atlantic is a crucial region when it comes to understanding the CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; dynamics in the tropics, as it is subject to large inputs of freshwater from the Amazon River and the ITCZ rainfall, as well as the input of CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-rich waters from upwelling of subsurface water. This study aims to reconstruct the surface marine carbonate system from 1998 to 2018 using sea surface temperature (SST) and sea surface salinity (SSS) data from the PIRATA buoy at 8&amp;amp;#176;N 38&amp;amp;#176;W and describe its variability in time. Two empirical models were used to calculate total alkalinity (TA) and dissolved inorganic carbon (DIC) from SSS. From these two parameters and SST data, it was possible to calculate pH and CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; fugacity (&amp;lt;em&amp;gt;f&amp;lt;/em&amp;gt;CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;) values. Only DIC, pH and &amp;lt;em&amp;gt;f&amp;lt;/em&amp;gt;CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; showed a statistically significant trend in time, where DIC showed an increase of 0.717 &amp;amp;#181;mol kg&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; year&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, pH decreased 0.001394 pH units year&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, and &amp;lt;em&amp;gt;f&amp;lt;/em&amp;gt;CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; had an increase of 1.539 &amp;amp;#181;atm year&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. Two different seasons were observed when data were analyzed: a dry season from January to June, when SSTs were lower (around 27&amp;amp;#176;C) and SSS was stable around 36, matching the period when the ITCZ is over the South American continent, Amazon river plume is restricted to western shelf areas and Equatorial upwelling is more active, and a rainy season from July to December, when SSTs were higher (around 28.5&amp;amp;#176;C) and SSS had higher variability (from 31 to 36), matching the period when the ITCZ is at its northern range, the Amazon plume is spread eastwards through the North Brazil Current&amp;amp;#8217;s retroflection and the Equatorial upwelling is less intense. Along with that, TA, DIC and pH varied positively with SSS, with higher values (TA around 2350 &amp;amp;#181;mol kg&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, DIC around 2025 &amp;amp;#181;mol kg&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; and pH around 8.060 pH units) during dry season and lower values (TA around 2300 &amp;amp;#181;mol kg&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, DIC around 1990 &amp;amp;#181;mol kg&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; and pH around 8.050 pH units) during rainy season. On the other hand, &amp;lt;em&amp;gt;f&amp;lt;/em&amp;gt;CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; varied positively with SST, with lower values (around 385 &amp;amp;#181;atm) during dry, upwelling season and higher values (around 390 &amp;amp;#181;atm) during rainy season, showing that both SSS and SST variability play an important role in the CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; solubility in the region.&amp;lt;/p&amp;gt;
Regional Studies in Marine Science, 2021
Abstract The Paraguacu River is one of the most important rivers in Bahia State, Brazil, and the ... more Abstract The Paraguacu River is one of the most important rivers in Bahia State, Brazil, and the main tributary of the Todos os Santos Bay, the second largest in that country. We evaluated the spatio-temporal variations in the composition and structure of the phytoplankton community in the Paraguacu River estuary as influenced by rainfall and fluvial discharge from the Pedra do Cavalo dam. Bi-monthly collections were carried out from May 2018 to March 2019 at 12 sampling stations in the estuary. During this period, phytoplankton samples, water samples to determinate the concentration of dissolved inorganic nutrients and data on salinity, temperature, pH, dissolved oxygen, and water transparency were collected. Data on rainfall and dam discharge were also obtained. Abiotic variables and chlorophyll-a showed significant differences in the estuary zones, and silicate concentrations demonstrated differences between the dam discharge periods. A total of 194 phytoplankton taxa were identified, with diatoms showing the highest densities and diversities throughout the study period. Cyclotella meneghiniana, Nitzschia sp., and Scrippsiella acuminata formed blooms in the dry season, whereas blooms of Planktothrix isothrix occurred in the rainy season and during a period of medium dam discharge in the dry season. The influence of dam discharge was quite evident, with increases in nutrient concentrations in the estuary during the months of higher flow that altered the composition and density of the phytoplankton communities in the different system zones. The formation of blooms in response to increased nutrient availability represents an increase in the primary productivity of the system, although blooms of potentially harmful species (such as Planktothrix isothrix) may represent a risk to human activities in the region.
Phytotaxa, 2019
The genus Metadinophysis was proposed by Nie & Wang (1941) based on their description of the new ... more The genus Metadinophysis was proposed by Nie & Wang (1941) based on their description of the new species Metadinophysis sinensis Nie & Wang, from collections in Ching-lan Bay, Hainan Province, China. In addition to the Pacific Ocean, coastal waters of Japan, Thailand, and Vietnam, the genus was recorded for the southern coast of Myanmar (Su-Myat et al. 2012) and more recently in New Caledonia (Chomérat 2016). The present study constitutes the first record of Metadinophysis sinensis for the tropical Atlantic Ocean, from collections made in five coastal systems located in the coast of Bahia (13°01’30” S and 038°34’40” W, 13°52’44” S and 038°57’58” W), northeastern Brazil (Fig. 1).
Rodriguésia, 2019
The phytoplankton community is the first link in the aquatic trophic chain and knowledge of its c... more The phytoplankton community is the first link in the aquatic trophic chain and knowledge of its composition is an important tool for ecological characterization; including as potential indicator of anthropic impacts. The southern coast of Bahia is one of the best preserved parts of the Brazilian coast, however, little is known about its biodiversity, especially on marine phycoflora. With the objective of characterizing the composition of microphytoplankton (> 20 µm) in this region, samples were collected by a horizontal dredger using a plankton net (20 µm mesh size) to study the community composition. Water samples were taken from the subsurface using a Van Dorn bottle in order to analyze phytoplanktonic cell concentration. A total of 149 taxa were identified, distributed in the following phyla: Bacillariophyta, Miozoa, Cyanobacteria, Euglenophyta, Haptophyta, and Ochrophyta. Diatoms (63%) and dinoflagellates (26%) were the most representative groups in the specific composition. ...
Marine Ecology, 2019
Functional groups have become an important tool for characterizing communities of marine and estu... more Functional groups have become an important tool for characterizing communities of marine and estuarine environments. Their use also holds promise for a better understanding of the temporal dynamics of phytoplankton. This study aimed to evaluate the contributions of phytoplankton size fractions and functional groups characterizing short‐term variation throughout tidal cycles and between dry and rainy seasons in a tropical estuarine system. Camamu Bay is an oligotrophic estuarine system that is under strong influence from tropical shelf waters and is characterized by high salinity and low concentrations of dissolved nutrients. Surface‐water samples were collected at nine sampling sites distributed among the three hydrodynamic regions of the bay, and at a mooring, at 3‐hr intervals during tidal cycles (12 hr each) in both the rainy and the dry season. Although the abundances of the phytoplankton fractions (pico‐, nano‐, and micro‐) were higher in the rainy season and during periods of ...
Brazilian Journal of Botany, 2018
Acta Botanica Brasilica, 2018
Hypnea pseudomusciformis was recently described from South America, and has three morphological v... more Hypnea pseudomusciformis was recently described from South America, and has three morphological variants: "musciformis", "nigrescens", and "valentiae". Information on the biology of these variants may help to explain this species' wide morphological variation despite the absence of genetic divergence among variants. More morphological and ecological data has accumulated on the "musciformis" variant occurring on the Brazilian coast than for the others. In this study, we described the reproductive morphology of a tropical "nigrescens" population and investigated its phenology to provide crucial biological information about this taxon, and perhaps also assist in answering questions about the systematics of H. pseudomusciformis variants. The population analyzed showed no significant fluctuations in its total biomass throughout the year. All reproductive stages were frequently recorded during this study, which contributes greatly to our knowledge of the reproductive morphology of the "nigrescens" variant. Phenological variations were correlated with environment variables, such as air and sea-surface temperatures, insolation, precipitation, and humidity. Male gametophytes were frequently present, which has never been reported for the "musciformis" variant. We showed that, despite being members of the same genetic species, the "nigrescens" and "musciformis" morphological variants exhibit remarkable differences in their ecology and biology.
Algal Research, 2018
Marine filamentous cyanobacteria are sources of biologically active secondary metabolites with po... more Marine filamentous cyanobacteria are sources of biologically active secondary metabolites with potential biotechnological application. Despite the extension and environmental variety of the Brazilian coast, floristic surveys of filamentous cyanobacteria are scarce. Studies on their biotechnological potential are even more limited. In this work, we sampled Neolyngbya (Oscillatoriaceae) populations along the Brazilian coast and evaluated the antimicrobial, antioxidant, and cytotoxic activities of their organic extracts. We also assessed the strains' genetic potential for production of cyanotoxins. The strains were cultivated in SWBG-11 medium. Extraction of biomass was carried out with methanol, ethanol, and acetic acid. Antimicrobial (against seven bacterial strains and the yeast Candida albicans), antioxidant (DPPH and ABTS radicals), and cytotoxic (brine shrimp) potential were evaluated. PCR reactions were performed to analyze the genetic potential for the production of microcystin, saxitoxin, and cylindrospermopsin. Brazilian marine filamentous cyanobacteria presented relevant antimicrobial capacity. Seven extracts from four Neolyngbya strains inhibited growth of almost all bacteria, while nine extracts from four strains inhibited C. albicans, with a minimum inhibitory concentration (MIC) range from 2.5 to 10.0 mg•mL −1. Methanolic extracts presented the greatest antioxidant potential for both DPPH and ABTS radicals, ranging from 50.0 to 98.3% at a concentration of 10 mg•mL −1. Cytotoxicity assays showed a LC 50 ranging from 0.8 to 6.6 mg•mL −1. We detected toxic genotypes in eight of the analyzed strains, in which the most frequent gene clusters were mcyG (microcystin) and cyrJ (cylindrospermopsin). All Neolyngbya strains screened in this study have potential for biotechnological application, which highlights the economical and pharmacological importance of studying this underestimated biodiversity in tropical areas.
Revista Intertox de Toxicologia, Risco Ambiental e Sociedade, 2015
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Papers by Helen Michelle Affe