PENNATE DIATOMS (BACILLARIOPHYCEAE) FLORA FROM TWO TROPICAL ESTUARIES IN PERNAMBUCO STATE, BRAZIL

Functional diversity of fish in tropical estuaries: A traits-based approach of communities in Pernambuco, Brazil

Assessment of wind resources in two parts of Northeast Brazil with the use of numerical models

Studies undertaken in the Atlantic Coastal Forest have revealed a notable floristic heterogeneity within this vegetation type in NE Brazil. However, there is still a great need for detailed comparisons of the floristic relationships between the various forest types found there. This work presents an analysis of the floristic similarity (at the species level) of these forest as revealed by floristic surveys, with the aim of better understanding and defining this vegetation. Using a binary matrix, grouping, ordering, and TWINSPAN analysis were performed on 742 tree/shrub species listed in 35 different plant surveys. These tree/shrub species were divided by these analysis into two large floristic groups – ombrophilous and semideciduous. The semideciduous group was formed, in general, by forest areas located at altitudes above 700 m (montane forests), and could itself be divided into two subgroups. The first subgroup was located more inland (Pernambuco), while the second subgroup was located nearer the coast (within the states of Pernambuco and Ceara). The ombrophilous group was quite heterogeneous, but could also be divided into two floristic subgroups: i) lowland forests (below 100 m a.s.l) in the states of Pernambuco, Paraiba, and in two areas of Bahia, as well as some montane forests (in Pernambuco, between 640 and 900 m a.s.l.); ii) lowlands forests in the states of Alagoas and Bahia. This latter subgroup is the largest and best defined, and has the highest degree of internal similarity. Nonetheless, it can be further subdivided into two smaller classes, one in Alagoas and the other in Bahia State. The results of this study demonstrate that the concept of the Atlantic Coastal Forest could also include montane ombrophilous forests in Pernambuco State, as these forests form a single floristic unit together with lowland forests in that state.

Enneapogon cenchroides (Roem. & Schult.) C.E. Hubb. is an herb native from Africa to India. In Brazil, this species invades areas of the Caatinga in the states of Pernambuco and Bahia. Its ability to affect the germination and development of other species makes it a threat to native flora. This article reports the first record of the invasion of E. cenchroides in the state of Sergipe and aims to (i) map the current distribution of this species in Northeast Brazil through Extent of Occurrence (EOO) and (ii) determine its potential distribution in the region through Species Distribution Modeling (SDM). The record of E. cenchroides in Sergipe was carried out in a riparian zone in the municipality of Canindé de São Francisco. Georeferenced points of E. cenchroides were obtained in its native and invaded environment. The points located in Brazil were used to delimit its EOO through the convex polygon. All points were used to develop the SDM through the Maxent, ANN, GLM, and CTA algorithms. With the new record in Sergipe, the EOO of E. cenchroides reached 124,145 km², a value 87.32% higher than that obtained in its first evaluation. According to the SDM, the areas of greatest suitability (0.60–1.0) were concentrated in the states of Bahia, Sergipe, Alagoas, Pernambuco, Paraíba, and Rio Grande do Norte, mainly in the Caatinga. The results indicate that E. cenchroides has been invading new areas since its initial introduction. Furthermore, the climatic suitability in Northeast Brazil may favor its spread in new areas.

Microcephaly in Brazil: confidence builds in Zika connection

Fucoxanthin-chlorophyll proteins (FCP) are the major light-harvesting proteins of diatom algae, a major contributor to marine carbon fixation. FCP complexes from representatives of centric (Cyclotella meneghiniana) and pennate (Phaeodactylum tricornutum) diatoms were prepared by sucrose gradient centrifugation and studied by means of electron microscopy followed by single particle analysis. The oligomeric FCP from a centric diatom were observed to take the form of unusual chain-like or circular shapes, a very unique supramolecular assembly for such antennas. The existence of the often disputed oligomeric form of FCP in pennate diatoms has been confirmed. Contrary to the centric diatom FCP, pennate diatom FCP oligomers are very similar to oligomeric antennas from related heterokont (Stramenopila) algae. Evolutionary aspects of the presence of novel light-harvesting protein arrangement in centric diatoms are discussed.

Although mojarra species usually demonstrate a wide distribution in tropical and subtropical estuaries, relatively little is known about the process influencing the spatial resource partitioning to nearshore habitats. Therefore, the aim of this study was check the existence of habitat and food partitioning among confamiliar species in a hypersaline estuary. The dietary compositions of three co‐occurring species of mojarras were determined, using samples collected with a beach seine from an inverse tropical estuary in Northeastern Brazil, during the rainy and the dry seasons of 2012. Eucinostomus argenteus and Ulaema lefroyi were abundant throughout the year, while Eugerres brasilianus was most abundant during the rainy season. Although these mojarras were found together in all areas of the estuary, there was evidence of habitat partitioning: E. argenteus and E. brasilianus were dominant in areas with submerged vegetation, while U. lefroyi was most abundant in areas with little habitat complexity and minimal shelter. All mojarras consumed, to different degrees, zooplankton, Bivalvia and Polychaeta. However, E. brasilanus also consumed a considerable amount of algae. Although the niches of the mojarra species appeared to significantly overlap, some resource partitioning patterns were apparent. While E. brasilanus was clearly different along the trophic niche, segregation of the other species was more important with respect to the spatial dimension. The different feeding strategies appear to minimize inter‐specific overlap and allow the co‐occurrence of these species in this hypersaline tropical estuary.

Abstract: The Atlantic Forest north of the São Francisco River, known as the Pernambuco Endemism Center (PEC), comprises small, poorly-known and, consequently, highly threatened forest remnants, such as Refúgio de Vida Silvestre (RVS) Matas do Siriji, a montane forest located in the municipality of São Vicente Férrer, state of Pernambuco, Northeast Brazil. We provide the results of the first inventory of the squamate fauna of the region with comments on the conservation status of some species, comparisons with other locations in Northeast Brazil and a brief discussion of biogeography. Time-constrained transects, pit-fall traps, occasional encounters and third-party records registered 18 lizard species and 25 snake species, with the rarefaction curve of the former tending to stability. The RVS Matas do Siriji possesses 39.81 % of the lizard and snake species known for the state of de Pernambuco, being the third richest area in species in the State, with a composition similar to that of other areas within PEC. Based on the lists of SEMAS, ICMBio and IUCN, some of the registered species are considered vulnerable to extinction while others have yet to be evaluated. The RVS Matas do Siriji includes a rich, threatened and underestimated fauna of squamate reptiles, indicating that more restrictive protection measures must be adopted in this Conservation Unit.

Tidal flow causes high temporal variability in environmental properties that impact ecosystem dynamics. Microbes such as phytoplankton are especially susceptible to tidal advection and mixing, and understanding their role in estuarine food webs and biogeochemical cycles requires information on their biomass and taxonomic composition over short time scales (e.g. tidal cycles). We conducted a survey of phytoplankton pigment biomass and taxonomic composition over complete tidal cycles in 2 salt marsh creeks on 5 sampling occasions from July to September 2000, and assessed environmental factors regulating phytoplankton properties. Tidal input of low chl a water combined with phytoplankton losses (microzooplankton grazing, oyster grazing, settling) caused large decreases in phytoplankton biomass (by 47 to 51% on average) on the flood tide, and also influenced the taxonomic composition. Depending on sampling date, pennate diatoms or flagellates were pri- marily reduced on the flood tide. One sampling date followed a heavy rain event, and was marked by substantial increases in tidal creek nutrient concentrations and reduced microzooplankton grazing rates, emphasizing the need to consider the combined influences of nutrients and grazing in explain- ing bloom formation following rain events. The high tidal variability in phytoplankton properties sug- gests that strict attention to tidal phase is needed in determining long-term trends or inter-estuary comparisons in phytoplankton biomass, and primary production in tidally-driven estuaries.

Protist entrapment in newly formed sea ice in the Coastal Arctic Ocean

Benthic community resilience in two differently impacted tropical estuaries: Taxonomic vs functional approaches

Are there general spatial patterns of mangrove structure and composition along estuarine salinity gradients in Todos os Santos Bay?

Em Pernambuco, além da Floresta Atlântica costeira, e dos Brejos de Altitude, as encostas orientais do Planalto da Borborema também são regiões ricas em espécies de Orchidaceae. Os afloramentos rochosos são comuns e têm sido indicados com uma das áreas mais representativas para a família no Nordeste do Brasil. O presente trabalho teve como objetivo inventariar a flora de orquídeas da área. Excursões foram realizadas entre 2005 e 2013, contemplando afloramentos rochosos de 13 áreas. Foram encontradas 29 spp. pertencentes a 18 gêneros, sendo Habenaria (seis spp.) e Epidendrum (quatro spp.) os mais representativos. Entre as espécies catalogadas destacam-se Acianthera prolifera e Octomeria alexandri como novos registros para Pernambuco, e Phragmipedium sargentianum que consta na lista de espécies ameaçadas de extinção no Brasil. As espécies são amplamente distribuídas a restritas na sua distribuição, dentre as quais, nove são endêmicas do Brasil. Este estudo corrobora informações anteriores sobre a elevada riqueza e abundância de Orchidaceae nas formações vegetais dos afloramentos rochosos, incluindo muitas espécies endêmicas. Apesar disto, poucas unidades de conservação no estado de Pernambuco englobam esse ecossistema tão importante.

A comparison of three tidal creeks assessed the effects of the hydrological regime on trophic organization in juvenile fish assemblages of 21 species in a tropical estuary in north-eastern Brazil. There were seven trophic guilds represented spatially. Zooplanktivore and zoobenthivore guilds dominated the lower estuary, whereas omnivores and detritivores dominated the upper estuary. In the rainy season, the zooplanktivore and omnivore guilds were more common throughout the estuary, but in the dry season, zoobenthivores and piscivores occurred throughout. The trophic organization results show that (1) there was a higher complexity in tidal creeks in the upper estuary compared with the first tidal creek in the lower region and (2) trophic linkages increased in the upper estuary, principally the number of omnivore and detritivore species. Spatial variation in trophic structure was primarily associated with differences in the location of the tidal creeks along the estuary, and this variability was partly attributed to fish species richness; the number of species increased towards the upper estuary, and additional species occupied different trophic levels or used additional resources.

Trophic flow structure of a neotropical estuary in northeastern Brazil and the comparison of ecosystem model indicators of estuaries