Effects of recent urbanization on carbon and nitrogen burial rates of sedimentary records in a tropical coastal lagoon (Brazil).

Land use and land cover changes (LULCC) are a global environmental issue that has impacted biogeochemical cycles worldwide. Sedimentary records can demonstrate the effects of LULCC on aquatic ecosystems, where the recent urbanization has been linked to changes in carbon and nitrogen burial. In this study, we reconstructed long-term LULCC and sedimentary records of carbon (C), nitrogen (N), phosphorus (P), and sediment burial rates in a eutrophic tropical coastal lagoon affected by recent urban expansion.

Bioprospecting for Endophytes with Potential to Promote Plant Growth.

is a native plant found only in a permanent pond in Serra dos Carajás in the Amazon region. Plant-associated microbial communities are recognized to be responsible for biological processes essential for the health, growth, and even adaptation of plants to environmental stresses. In this sense, the aims of this work were to isolate, identify, and evaluate the properties of endophytic bacteria isolated from The bioprospecting of potentially growth-promoting endophytes required the following steps to be taken: isolation of endophytic colonies, molecular identification by 16S rDNA sequence analysis, and evaluation of the bacterial potential for nitrogen fixation, production of indole acetic acid and siderophores, as well as phosphate solubilization and mineralization.

Conservation implications of genetic structure in the narrowest endemic quillwort from the Eastern Amazon.

The quillwort is a critically endangered species occurring in a single lake in Serra dos Carajás, Eastern Amazon. Low genetic diversity and small effective population sizes ( ) are expected for narrow endemic species (NES). Conservation biology studies centered in a single species show some limitations, but they are still useful considering the limited time and resources available for protection of species at risk of extinction.

The genetic diversity and population structure of two endemic Amazonian quillwort ( L.) species.

Background: Two endemic lycophyte species and have been recently described in the State of Pará in the Amazon forest located in northern Brazil. L. has survived through three mass extinctions.

Small is better: comparing the efficiency of two Surber samplers' sizes for biomonitoring programs in tropical headwater streams in the Amazon region.

This study aimed to compare the efficiency of two different sizes of the Surber sampler to assess benthic macroinvertebrates in headwater streams in two Amazonian regions. Two Surber samplers of different sizes were used, one measuring 20 × 20 cm and the other 30 × 30 cm, both with a 0.25-mm net.

Species identity and diversity effects on invasion resistance of tropical freshwater plant communities.

Biotic resistance mediated by native plant diversity has long been hypothesized to reduce the success of invading plant species in terrestrial systems in temperate regions. However, still little is known about the mechanisms driving invasion patterns in other biomes or latitudes. We help to fill this gap by investigating how native plant community presence and diversity, and the presence of native phylogenetically closely related species to an invader, would affect invader Hydrilla verticillata establishment success in tropical freshwater submerged plant communities.

Global regulation of methane emission from natural lakes.

Methane (CH) emissions from lakes are the largest of the emissions from freshwater ecosystems. We compile open water CH emission estimates from individual lakes from all over the world and consider the three main emission pathways: diffusive; ebullitive; and storage. The relationships between emissions, environmental variables, lake characteristics and methodological approaches are investigated for the measurements from 297 lakes.

The Hydroalcoholic Extract of Leaves of Mandevilla moricandiana Induces NO-Mediated Vascular Relaxation.

Natural products extracted from plants represent a valuable source of new bioactive substances. Many studies describe the potential of plant products for the treatment of cardiovascular diseases. Species of the genus have been studied for their biological activities, mainly as antioxidant, anti-inflammatory, and vasorelaxant.

Controls of Sediment Nitrogen Dynamics in Tropical Coastal Lagoons.

Sediment denitrification rates seem to be lower in tropical environments than in temperate environments. Using the isotope pairing technique, we measured actual denitrification rates in the sediment of tropical coastal lagoons. To explain the low denitrification rates observed at all study sites (<5 μmol N2 m-2 h-1), we also evaluated potential oxygen (O2) consumption, potential nitrification, potential denitrification, potential anammox, and estimated dissimilatory nitrate (NO3-) reduction to ammonium (NH4+; DNRA) in the sediment.

Nitric Oxide Production Inhibition and Anti-Mycobacterial Activity of Extracts and Halogenated Sesquiterpenes from the Brazilian Red Alga Laurencia Dendroidea J. Agardh.

Background: Red algae of the genus Laurencia J. V. Lamouroux are a rich source of secondary metabolites with important pharmacological activities such as anti-tumoral, anti-inflammatory, anti-fungal, anti-viral, anti-leishmanial, anti-helminthic, anti-malarial, anti-trypanosomal, anti-microbial as well as anti-bacterial against Mycobacterium tuberculosis.

Acute toxicity bioassay with the amphipod, Grandidierella bonnieroides S. after exposure to sediments from an urban estuary (Macaé River Estuary, RJ, Brazil).

Acute toxicity to Grandidierella bonnieroides and physicochemical analysis were used for quality assessment of the sediment of the Macaé River urban estuary, located in the Brazilian coast where rapid socioeconomic growth has been induced by offshore oil and gas exploration at the Campos Basin. Sediment samples were collected during four events in four sampling sites of the estuary and also in a control site. Organism mortality after exposure to the estuarine sediments was, on average, 30 % a value higher than in the control site where it was 10 %.