Terrestrial inputs boost organic carbon accumulation in Mexican mangroves.

Despite their ability to mitigate climate change by efficiently absorbing atmospheric carbon dioxide (CO) and acting as natural long-term carbon sinks, mangrove ecosystems have faced several anthropogenic threats over the past century, resulting in a decline in the global mangrove cover. By using standardized methods and the most recent Bayesian tracer mixing models MixSIAR, this study aimed to quantify source contributions, burial rates, and stocks of organic carbon (C) and explore their temporal changes (∼100 years) in seven lead-210 dated sediment cores collected from three contrasting Mexican mangrove areas. The spatial variation in C burial rates and stocks in these blue carbon ecosystems primarily depended on the influence of local rivers, which controlled C sources and fluxes within the mangrove areas.

Leaf-level photosynthetic capacity dynamics in relation to soil and foliar nutrients along forest-savanna boundaries in Ghana and Brazil.

Forest-savanna boundaries extend across large parts of the tropics but the variability of photosynthetic capacity in relation to soil and foliar nutrients across these transition zones is poorly understood. For this reason, we compared photosynthetic capacity (maximum rate of carboxylation of Rubisco at 25 C° (Vcmax25), leaf mass, nitrogen (N), phosphorus (P) and potassium (K) per unit leaf area (LMA, Narea, Parea and Karea, respectively), in relation to respective soil nutrients from 89 species at seven sites along forest-savanna ecotones in Ghana and Brazil. Contrary to our expectations, edaphic conditions were not reflected in foliar nutrient concentrations but LMA was slightly higher in lower fertility soils.

Variations in the relative abundance of Wolbachia in the gut of Nasutitermes arborum across life stages and castes.

There are multiple forms of interactions between termites and bacteria. In addition to their gut microbiota, which has been intensively studied, termites host intracellular symbionts such as Wolbachia. These distinct symbioses have been so far approached independently and mostly in adult termites.

Environmental impact of the largest petroleum terminal in SE Brazil: A multiproxy analysis based on sediment geochemistry and living benthic foraminifera.

The Dutos e Terminais do Centro Sul (DTCS) is one of the largest petroleum terminals of the South America located in the São Sebastião Channel (SSC) on the southeastern Brazilian coast. The aims of this study were to compare the sediment quality near the DTCS with that of several sites in the SSC region including the Araçá (AR) domestic sewage outfall and to assess the efficiency of the DTCS wastewater treatment plant. To achieve these goals, textural, geochemical, and living benthic foraminifera results were analyzed for the DTCS, AR, and SSC regions.

Evidence from the gut microbiota of swarming alates of a vertical transmission of the bacterial symbionts in Nasutitermes arborum (Termitidae, Nasutitermitinae).

Studies on termite symbiosis have revealed that significant symbiont lineages are maintained across generations. However, most studies have focused only on the worker caste. Little is known about the gut microbiota of reproductives, the most probable vectors for transmitting these lineages to offspring.

Aragonite saturation state in a tropical coastal embayment dominated by phytoplankton blooms (Guanabara Bay - Brazil).

The dynamics of the aragonite saturation state (Ω) were investigated in the eutrophic coastal waters of Guanabara Bay (RJ-Brazil). Large phytoplankton blooms stimulated by a high nutrient enrichment promoted the production of organic matter with strong uptake of dissolved inorganic carbon (DIC) in surface waters, lowering the concentrations of dissolved carbon dioxide (CO), and increasing the pH, Ω and carbonate ion (CO), especially during summer. The increase of Ω related to biological activity was also evident comparing the negative relationship between the Ω and the apparent utilization of oxygen (AOU), with a very close behavior between the slopes of the linear regression and the Redfield ratio.

From shifting cultivation to teak plantation: effect on overland flow and sediment yield in a montane tropical catchment.

Soil erosion supplies large quantities of sediments to rivers of Southeastern Asia. It reduces soil fertility of agro-ecosystems located on hillslopes, and it degrades, downstream, water resource quality and leads to the siltation of reservoirs. An increase in the surface area covered with commercial perennial monocultures such as teak plantations is currently observed at the expanse of traditional slash-and-burn cultivation systems in steep montane environments of these regions.

Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments.

Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E.

Characteristics of soils in selected maize growing sites along altitudinal gradients in East African highlands.

Maize is the main staple crop in the East African Mountains. Understanding how the edaphic characteristics change along altitudinal gradients is important for maximizing maize production in East African Highlands, which are the key maize production areas in the region. This study evaluated and compared the levels of some macro and micro-elements (Al, Ca, Fe, K, Mg, Mn, Na and P) and other soil parameters (pH, organic carbon content, soil texture [i.

Profiling the Succession of Bacterial Communities throughout the Life Stages of a Higher Termite Nasutitermes arborum (Termitidae, Nasutitermitinae) Using 16S rRNA Gene Pyrosequencing.

Previous surveys of the gut microbiota of termites have been limited to the worker caste. Termite gut microbiota has been well documented over the last decades and consists mainly of lineages specific to the gut microbiome which are maintained across generations. Despite this intimate relationship, little is known of how symbionts are transmitted to each generation of the host, especially in higher termites where proctodeal feeding has never been reported.

Foraminiferal assemblages as bioindicators to assess potential pollution in mangroves used as a natural biofilter for shrimp farm effluents (New Caledonia).

In New Caledonia, semi-intensive shrimp farms release untreated effluents into the mangrove. Foraminiferal assemblages were analyzed for assessing the impact of effluent release on the benthic compartment. Comparison was made between samples collected (1) in an effluent receiving mangrove before and after the rearing cycle, and (2) for one-year monitoring an effluent receiving and a control mangrove.

The niche reduction approach: an opportunity for optimal control of infectious diseases in low-income countries?

Background: During the last century, WHO led public health interventions that resulted in spectacular achievements such as the worldwide eradication of smallpox and the elimination of malaria from the Western world. However, besides major successes achieved worldwide in infectious diseases control, most elimination/control programs remain frustrating in many tropical countries where specific biological and socio-economical features prevented implementation of disease control over broad spatial and temporal scales. Emblematic examples include malaria, yellow fever, measles and HIV.

Gross and microscopic pathology of hard and soft corals in New Caledonia.

We surveyed the reefs of Grande Terre, New Caledonia, for coral diseases in 2010 and 2013. Lesions encountered in hard and soft corals were systematically described at the gross and microscopic level. We sampled paired and normal tissues from 101 and 65 colonies in 2010 and 2013, respectively, comprising 51 species of corals from 27 genera.

The impact of community organization on vector-borne pathogens.

Vector-borne zoonotic disease agents, which are known to often infect multiple species in the wild, have been identified as an emerging threat to human health. Understanding the ecology of these pathogens is especially timely, given the continued anthropogenic impacts on biodiversity. Here, we integrate empirical scaling laws from community ecology within a theoretical reservoir-vector-pathogen framework to study the transmission consequences of host community structure and diversity within large assemblages.

Linking community and disease ecology: the impact of biodiversity on pathogen transmission.

The increasing number of zoonotic diseases spilling over from a range of wild animal species represents a particular concern for public health, especially in light of the current dramatic trend of biodiversity loss. To understand the ecology of these multi-host pathogens and their response to environmental degradation and species extinctions, it is necessary to develop a theoretical framework that takes into account realistic community assemblages. Here, we present a multi-host species epidemiological model that includes empirically determined patterns of diversity and composition derived from community ecology studies.