Benthic foraminiferal response to trace element pollution—the case study of the Gulf of Milazzo, NE Sicily (Central Mediterranean Sea)

The response of benthic foraminiferal assemblages to trace element pollution in the marine sediments of the Gulf of Milazzo (north-eastern Sicily) was investigated. Since the 1960s, this coastal area has been a preferred site for the development of two small marinas and a commercial harbour as well as for heavy industry. Forty samples collected in the uppermost 3–4 cm of an undisturbed layer of sediment in the littoral environment were used for this benthic foraminiferal analysis. The enrichment factors (EFs) of selected trace elements (As, Co, Cr, Cu, Mn, Ni, Pb and Zn) were also calculated. Changes both in benthic foraminiferal assemblages and in some trace elements concentrations have provided evidence that the gulf’s littoral zone can be subdivided into three sectors characterised by environmental changes in the marine ecosystem. In the sector unpolluted, close to the Milazzo Cape, foraminiferal assemblages exhibit high values of species richness and foraminiferal density while trace element concentrations and their EFs are very low. Here, the highest densities of Miliolids and epiphytic species are present. On the contrary, in the sector polluted, from the marinas to the crude oil refinery, foraminiferal density and species diversity are low, and assemblages are dominated, albeit with very low densities, by species that tolerate stressed environmental conditions, such as LOFAs, agglutinants and Ammonia spp. Here, the highest trace elements concentrations of Pb, Zn and Cu and related EFs were detected. Eastwards, in the sector moderately polluted, foraminiferal populations are quite poor. They are characterised by low values of species richness and foraminiferal densities, nevertheless trace element concentrations become lower than in the other sectors and their EFs are often below 1. Deformed foraminifera, with percentages up to 7.14 %, were found in all three of the sectors. Differences in benthic foraminiferal assemblages, coupled with results from statistical analysis, indicate that anthropogenic trace element pollution could be considered as one of the most important causes of the modifications of foraminiferal assemblages in the study area.     

Fetal echocardiography using transvaginal and transabdominal probes during the first period of pregnancy: A comparative study

The authors compare the diagnostic possibilities of fetal transabdominal echocardiography versus transvaginal echocardiography. A larger diagnostic capacity is verified in different gestation ages with transvaginal probe between the 11th and 14th week of gestation. The results are emphasized by colour Doppler.     

Resource competition between two fungal parasites in subterranean termites

Subterranean termites live in large groups in underground nests where the pathogenic pressure of the soil environment has led to the evolution of a complex interaction among individual and social immune mechanisms in the colonies. However, groups of termites under stress can show increased susceptibility to opportunistic parasites. In this study, an isolate of Aspergillus nomius Kurtzman, Horn & Hessltine was obtained from a collapsed termite laboratory colony. We determined that it was primarily a saprophyte and, secondarily, a facultative parasite if the termite immunity is undergoing a form of stress. This was determined by stressing individuals of the Formosan subterranean termite Coptotermes formosanus Shiraki via a co-exposure to the virulent fungal parasite Metarhizium anisopliae (Metch.) Sorokin. We also examined the dynamics of a mixed infection of A. nomius and M. anisopliae in a single termite host. The virulent parasite M. anisopliae debilitated the termite immune system, but the facultative, fast growing parasite A. nomius dominated the mixed infection process. The resource utilization strategy of A. nomius during the infection resulted in successful conidia production, while the chance for M. anisopliae to complete its life cycle was reduced. Our results also suggest that the occurrence of opportunistic parasites such as A. nomius in collapsing termite laboratory colonies is the consequence of a previous stress, not the cause of the stress.     

On the importance of size of plastic fragments and pellets on the strandline: a snapshot of a Brazilian beach

Virgin plastic pellets and plastic fragments are reported as ubiquitous beach contaminants in the peer-reviewed literature. A surface density of 0.3 virgin plastic pellets and plastic fragments per square centimeter of the strandline area was registered on an urban beach of the northeast of Brazil. This beach is presently not affected by petrochemical facilities or pellet processing plants. The main source of fragments (96.7%) was attributed to the breaking down of larger plastic items deposited on the beach. In the case of virgin plastic pellets (3.3%), the main sources were the marine environment and possibly nearby port facilities. This category of plastic pollutant offers particular threats to the marine environment and to beach users.     

Agricultural nitrate monitoring in a lake basin in Central Italy: a further step ahead towards an integrated nutrient management aimed at controlling water pollution

Water pollution from point sources has been considerably reduced over the last few decades. Nevertheless, some water quality problems remain, which can be attributed to non-point pollution sources, and in particular to agriculture. In this paper the results of a study intended to assess the consequences, in terms of NO₃ water pollution, of growing a crop, whose impact in terms of P pollution is already well known, are presented. The potential consequences, in terms of water pollution from nitrates of a BMP expressly applied to reduce P pollution are also discussed. The study site is the Lake Vico basin, Central Italy, which has suffered a shift in trophic state since the mid 1990s, caused by P compounds used for intensive cultivation of hazelnut trees. The results of the monitoring campaign described in this paper allow to assert that hazelnut tree cropping has probably caused a considerable increase in nitrate concentration in the groundwater, although not in the lake water, because of the specific hydrogeological characteristics of the basin. The main conclusion is that monitoring is essential to single out environmental characteristics peculiar of a specific area, which even the most sophisticated model would not have been able to highlight. This is why monitoring and model simulations should be integrated.     

Pesticide distribution in an agricultural environment in Argentina

An assessment of the off-site migration of pesticides from agricultural activity into the environment in the Neuquen River Valley was performed. The aim of this study was to evaluate the distribution of pesticides in several compartments of a small agricultural sub-catchment. Soil, surface water, shallow groundwater and drift deposition were analyzed for pesticide residues. Results showed the presence of some pesticide residues in soil, surface water and shallow groundwater compartments. The highest detection frequencies in water (surface and subsurface) were found for azinphos-methyl and chlorpyrifos (>70%). In terms of concentration, the highest levels were observed in shallow groundwater for azinphos methyl (22.5 μg/L) and carbaryl (45.7 μg/L). In the soil, even before the application period had started, accumulation of residues was present. These residues increased during the period studied. Spray drift during pesticide application was found to be a significant pathway for the migration of pesticide residues in surface water, while leaching and preferential flows were the main transport routes contributing to subsurface contamination.     

Influence of lignin, pentachlorophenol and heavy metal on antibiotic resistance of pathogenic bacteria isolated from pulp paper mill effluent contaminated river water

Pulp paper mill pollutants are the major source of aquatic contamination having metals, lignin and chlorophenols. Study was conducted to see the effect of these contaminants on antibiotic resistance pattern of isolated bacteria. Pulp paper effluents were evaluated for its physico-chemical properties i.e, BOD 72143 +/- 164.81 to 22.32 +/- 2.48, COD 213136 +/- 583.59 to 60.40 +/- 6.34, total phenol 386 +/- 71.24 to 0.43 +/- 0.0, lignin 26312 +/- 258.59 to 73.67 +/- 31.81and microbial quality i.e. K. pneumonae, S. typhi, S. faecalis, P. aeruginosa, E. coli, Ent. faecalis, A. hydrophila, B. subtilis, S. aureus, Y enterolitica and V vulrificus. Antibiotic sensitivity (10-30 microg), heavy metal resistance (100-1000 microg ml(-1)), lignin (1000-10,000 ppm) and pentachlorophenol (100-1000 ppm) tolerance of bacterial strains were assessed by seven classes of antibiotics. Eleven bacterial isolates were found multidrug resistant towards antibiotics, heavy metal, lignin and PCP. Out of 11 isolates, 90.9% were found resistant against eleven antibiotics which acquired 100% resistant in presence of heavy metal, lignin and chlorophenols. Results also revealed that concentration of lignin (50-350 ppm) and PCP (5-30 ppm) induced maximum growth (273-8050 cfu ml(-1)) of pathogenic bacteria in river water.     

Grassland invader responses to realistic changes in native species richness.

The importance of species richness for repelling exotic plant invasions varies from ecosystem to ecosystem. Thus, in order to prioritize conservation objectives, it is critical to identify those ecosystems where decreasing richness will most greatly magnify invasion risks. Our goal was to determine if invasion risks greatly increase in response to common reductions in grassland species richness. We imposed treatments that mimic management-induced reductions in grassland species richness (i.e., removal of shallow- and/or deep-rooted forbs and/or grasses and/or cryptogam layers). Then we introduced and monitored the performance of a notorious invasive species (i.e., Centaurea maculosa). We found that, on a per-gram-of-biomass basis, each resident plant group similarly suppressed invader growth. Hence, with respect to preventing C. maculosa invasions, maintaining overall productivity is probably more important than maintaining the productivity of particular plant groups or species. But at the sites we studied, all plant groups may be needed to maintain overall productivity because removing forbs decreased overall productivity in two of three years. Alternatively, removing forbs increased productivity in another year, and this led us to posit that removing forbs may inflate the temporal productivity variance as opposed to greatly affecting time-averaged productivity. In either case, overall productivity responses to single plant group removals were inconsistent and fairly modest, and only when all plant groups were removed did C. maculosa growth increase substantially over a no-removal treatment. As such, it seems that intense disturbances (e.g., prolonged drought, overgrazing) that deplete multiple plant groups may often be a prerequisite for C. maculosa invasion.     

Microbial community variation and its relationship with nitrogen mineralization in historically altered forests

Past land use can impart soil legacies that have important implications for ecosystem function. Although these legacies have been linked with microbially mediated processes, little is known about the long-term influence of land use on soil microbial communities themselves. We examined whether historical land use affected soil microbial community composition (lipid profiles) and whether community composition was related to potential net nitrogen (N) mineralization rates in southern Appalachian (USA) forest stands abandoned from agriculture or logging and reforested >50 yr ago. Microbial community composition was determined by a hybrid procedure of phospholipid fatty acid (PLFA) and fatty acid methyl ester (FAME) analysis. We found that community composition varied significantly with past land use. Communities in formerly farmed stands had a higher relative abundance of markers for gram-negative bacteria and a lower abundance of markers for fungi compared with previously logged and reference (i.e., no disturbance history) stands. Potential net N mineralization rates were negatively correlated with fungal and gram-negative bacterial markers in both farmed and reference stands, and fungal abundance and soil bulk density effectively predicted mineralization rates in all stands. Our results indicate that the alteration of microbial communities by historical land use may influence the ecosystem processes they mediate. This is in contrast to typical expectations about microbial community resilience to change. Here, the decrease in fungal abundance observed from disturbance appeared to result in decreased nitrogen mineralization over the long term.     

Allelopathic effect of four weed species extracts on germination, growth and protein in different varieties of Glycine max (L.) Merrill

Allelopathic effect of Ageratum conyzoides L., Cynodon dactylon (L.) Pers., Parthenium hysterophorus L., and Solanum nigrum L. were examined on seed germination, seedling growth, total protein content and protein profile on Ankur, Bhatt, Bragg, PK -416, PS-1042 and Shilajeet varieties of soybean (Glycine max (L) Merill). Aqueous extracts of weeds (10% w/v) showed both inhibitory and stimulatory influence on percent seed germination and seedling growth in different varieties of soybean. On the basis of per cent reduction in different parameters, the variety Bragg and PS-1042, and Shilajeet were resistant and susceptible respectively to different weed extracts, and among weed extracts, S. nigrum was most effective followed by P. hysterophorus compared to others. The total protein content (mg/g f wt.) in different varieties was increased with all the weed extracts except Bragg with C. dactylon and P. hysterophorus, PS-1042 with A. conyzoides and Shilajeet with C. dactylon, in which it was decreased. The protein banding pattern in different varieties not only differ between control and treatments but also among treatments. The order of susceptibility of different varieties with different weed extracts followed the order: Ankur > PK-416 > Bhatt > Shilajeet > Bragg and > PS-1042.