Habitat use of a coastal delphinid population investigated using passive acoustic monitoring

相似文献   

Seroprevalence of economically important viral pathogens in swine populations of Trinidad and Tobago,West Indies

The objective of this study was to evaluate the seroprevalence and identify the strains of swine influenza virus (SwIV), as well as the seroprevalence of porcine parvovirus (PPV), transmissible gastroenteritis virus (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine respiratory coronavirus (PRCV), porcine circovirus type 2 (PCV-2), and classical swine fever virus (CSFV) in pigs in Trinidad and Tobago (T&T). Blood samples (309) were randomly collected from pigs at farms throughout T&T. Serum samples were tested for the presence of antibodies to the aforementioned viruses using commercial ELISA kits, and the circulating strains of SwIV were identified by the hemagglutination inhibition test (HIT). Antibodies against SwIV were detected in 114 out of the 309 samples (37%). Out of a total of 26 farms, 14 tested positive for SwIV antibodies. HI testing revealed high titers against the A/sw/Minnesota/593/99 H3N2 strain and the pH1N1 2009 pandemic strain. Antibodies against PPV were detected in 87 out of the 309 samples (28%), with 11 out of 26 farms testing positive for PPV antibodies. Antibodies against PCV-2 were detected in 205 out of the 309 samples tested (66%), with 25 out of the 26 farms testing positive for PCV-2 antibodies. No antibodies were detected in any of the tested pigs to PRRSV, TGEV, PRCV, or CSFV.     

Effects of nitrogen fertilizer on the acidification of two typical acid soils in South China

Purpose

A laboratory incubation under constant temperature and humidity was conducted to estimate the impacts of nitrogen (N) fertilizers on the acidification of two acid soils (Plinthudult and Paleudalfs) in south China.

Materials and methods

The experiment had three treatments, i.e., control (CK), addition of urea (U), and addition of ammonium sulfate (AS). We measured soil pH, nitrate (NO₃ ^?), ammonium (NH₄ ⁺), exchangeable hydrogen ion (H⁺), and aluminum ion (Al³⁺) concentrations at various intervals during the 90 days of incubation. Soil buffering capacity (pHBC) was also measured at the end of the experiment.

Results and discussion

The application of N fertilizers resulted in soil acidification. The U treatment caused greater acidification of the Plinthudult soil than the AS treatment, while there were no differences between U and AS treatments on the acidification of the Paleudalfs. At the end of the trial, the pHBC of Plinthudult in AS treatment was greater than that in CK and U treatments, which may be due to the buffering system of NH₄ ⁺ and NH₄OH. However, the pHBC of Paleudalfs was unchanged between treatments. The dynamics of exchangeable H⁺ and Al³⁺ corresponded to that of soil pH. Correlation analysis showed that both soil exchangeable H⁺ and soil exchangeable Al³⁺ were significantly related to soil pH.

Conclusions

Application of urea and ammonium sulfate caused acidification in both soils and increased soil exchangeable Al³⁺ and H⁺ concentrations in the Paleudalfs. The application of urea increased exchangeable Al³⁺, and ammonium sulfate increased pHBC in the Plinthudult.     

Effect of land use on the abundance and diversity of autotrophic bacteria as measured by ribulose-1,5-biphosphate carboxylase/oxygenase (RubisCO) large subunit gene abundance in soils

Elucidating the biodiversity of CO₂-assimilating bacterial communities under different land uses is critical for establishing an integrated view of the carbon sequestration in agricultural systems. We therefore determined the abundance and diversity of CO₂ assimilating bacteria using terminal restriction fragment length polymorphism and quantitative PCR of the cbbL gene (which encodes ribulose-1,5-biphosphate carboxylase/oxygenase). These analyses used agricultural soils collected from a long-term experiment (Pantang Agroecosystem) in subtropical China. Soils under three typical land uses, i.e., rice–rice (RR), upland crop (UC), and paddy rice–upland crop rotation (PU), were selected. The abundance of bacterial cbbL (0.04 to 1.25?×?10⁸ copies g^?1 soil) and 16S rDNA genes (0.05–3.00?×?10¹⁰ copies g^?1 soil) were determined in these soils. They generally followed the trend RR?>?PU?>?UC. The cbbL-containing bacterial communities were dominated by facultative autotrophic bacteria such as Mycobacterium sp., Rhodopseudomonas palustris, Bradyrhizobium japonicum, Ralstonia eutropha, and Alcaligenes eutrophus. Additionally, the cbbL-containing bacterial community composition in RR soil differed from that in upland crop and paddy rice–upland crop rotations soils. Soil organic matter was the most highly statistically significant factor which positively influenced the size of the cbbL-containing population. The RR management produced the greatest abundance and diversity of cbbL-containing bacteria. These results offer new insights into the importance of microbial autotrophic CO₂ fixation in soil C cycling.     

Passive surveillance (1987 to 2004) of United Kingdom bats for European bat lyssaviruses

Passive surveillance for European bat lyssaviruses (eblvs) in the uk began in 1987, and between 1987 and 2004, 4,883 bats of European origin (4,871 belonging to 17 UK resident species and 12 belonging to seven non-uk resident species) were tested. The proportions and numbers of each species submitted from different regions varied considerably, partly owing to inherent biases in the passive surveillance, and there were seasonal variations in the numbers, sex and age of the bats. Contact with cats was reported in approximately 30 per cent of the bats submitted. Daubenton's bat (Myotis daubentonii) was the only species found to be positive for lyssavirus infection, with four cases of eblv type 2 identified, in 1996, 2002, 2003 and 2004. No active infection with eblv type 1 was recorded.     

Impact of black carbon addition to soil on the determination of soil microbial biomass by fumigation extraction

The efficiency of the fumigation extraction method on the determination of soil microbial biomass carbon and ninhydrin-N was tested in three different soils (UK grassland, UK arable, Chinese arable) amended with black carbon (biochar or activated charcoal). Addition of activated charcoal to soil resulted in a significant decrease in K₂SO₄ extractable carbon and ninhydrin-N in all three soils, whereas the addition of biochar generally did not. A lower concentration of the extraction reagent (0.05 M vs. 0.5 M K₂SO₄) resulted in a significantly lower extraction efficiency in the grassland soil. The extraction efficiency of organic carbon was more affected by black carbon than that of ninhydrin-N, which resulted in a decreased biomass C/ninhydrin-N ratio. The impact of black carbon on the extraction efficiency of soil microbial biomass depended on the type of black carbon, on the concentration of the extraction medium and on soil type.