Source areas of phosphorus transfer in an agricultural catchment,south-eastern Norway

Abstract

The strategy to mitigate phosphorus (P) losses in areas of arable cropping in Norway has focused on measures to reduce erosion. Risk assessment of erosion has formed the basis for implementation of the measures. The soil P content has increased during recent decades, motivating an evaluation of its effect on P transfer in the landscape. The present study describes the spatial variability of runoff P concentrations from an agricultural dominated catchment (4.5 km²), representative for agriculture in south-eastern Norway. The concentrations of suspended sediments (SS), total P (TP) and dissolved reactive P (DRP) in runoff from 22 subcatchments (0.3–263 ha) during one year (monthly and during runoff-events) were evaluated. Contributions from point sources were 38 kg TP yr^?1 compared to a total P loss of 685 kg yr^?1 from the whole catchment. During low flow, mean diffuse TP concentration in runoff from subcatchments varied from 28 to 382 µg l^?1. The mean low flow TP concentration was 39 µg l^?1 from the housing area (only diffuse runoff) and 33 µg l^?1 from the forested area. During high flow the highest diffuse TP concentration was measured in an area with high erosion risk and high soil P status. At the subcatchment level the transfer of SS varied from 25 to 175% of the whole catchment SS transfer. Correspondingly for TP, the transfer varied from 50 to 260% of the whole catchment TP transfer. For each of five agricultural subcatchments the slope of the relationship between TP and SS concentrations reflected the mean soil P status of the subcatchment. Erosion risk estimates were closely related to the SS concentration (R²=0.83). The study illustrates that soil P status in addition to soil erosion is an important factor for P transfer.     

The impact of a national mass media campaign in The Netherlands on the prevention of weight gain

OBJECTIVE: A 5-year nationwide mass media campaign aimed at prevention of overweight was organised from 2002 onwards. The present study evaluates the first campaign, which was aimed primarily at increasing awareness of weight gain. DESIGN AND SUBJECTS: Data were collected by telephone interview in four independent cross-sectional surveys among non-obese Dutch adults aged 25-35 years (total n = 1,949) for statistical analyses. Awareness of personal body-weight status, overweight-related risk perceptions, attitudes towards weight-gain prevention, motivation to prevent weight gain and self-reported body mass index (BMI) were measured in each survey. Campaign exposure was assessed in the post-intervention surveys. To identify intervention effects over time multiple linear and logistic regression analyses were used, adjusted for secular time effects and age. RESULTS: After the campaign about 65% of the respondents knew about the campaign. The campaign was associated with more positive attitudes towards the prevention of weight gain (beta = 0.16; P < 0.01) and higher self-reported BMI (beta = 0.14; P < 0.01). CONCLUSIONS: The results suggest that the first campaign reached a large proportion of the population and initiated some positive change in attitudes, but did not achieve significant improvements in other determinants of weight-gain prevention among non-obese young adults.     

Macroscopic hierarchical surface patterning of porphyrin trimers via self-assembly and dewetting

The use of bottom-up approaches to construct patterned surfaces for technological applications is appealing, but to date is applicable to only relatively small areas (approximately 10 square micrometers). We constructed highly periodic patterns at macroscopic length scales, in the range of square millimeters, by combining self-assembly of disk-like porphyrin dyes with physical dewetting phenomena. The patterns consisted of equidistant 5-nanometer-wide lines spaced 0.5 to 1 micrometers apart, forming single porphyrin stacks containing millions of molecules, and were formed spontaneously upon drop-casting a solution of the molecules onto a mica surface. On glass, thicker lines are formed, which can be used to align liquid crystals in large domains of square millimeter size.     

Orthographic processing in baboons (Papio papio)

Skilled readers use information about which letters are where in a word (orthographic information) in order to access the sounds and meanings of printed words. We asked whether efficient processing of orthographic information could be achieved in the absence of prior language knowledge. To do so, we trained baboons to discriminate English words from nonsense combinations of letters that resembled real words. The results revealed that the baboons were using orthographic information in order to efficiently discriminate words from letter strings that were not words. Our results demonstrate that basic orthographic processing skills can be acquired in the absence of preexisting linguistic representations.     

Deciphering the rhizosphere microbiome for disease-suppressive bacteria

Disease-suppressive soils are exceptional ecosystems in which crop plants suffer less from specific soil-borne pathogens than expected owing to the activities of other soil microorganisms. For most disease-suppressive soils, the microbes and mechanisms involved in pathogen control are unknown. By coupling PhyloChip-based metagenomics of the rhizosphere microbiome with culture-dependent functional analyses, we identified key bacterial taxa and genes involved in suppression of a fungal root pathogen. More than 33,000 bacterial and archaeal species were detected, with Proteobacteria, Firmicutes, and Actinobacteria consistently associated with disease suppression. Members of the γ-Proteobacteria were shown to have disease-suppressive activity governed by nonribosomal peptide synthetases. Our data indicate that upon attack by a fungal root pathogen, plants can exploit microbial consortia from soil for protection against infections.     

A common genetic variant is associated with adult and childhood obesity

Obesity is a heritable trait and a risk factor for many common diseases such as type 2 diabetes, heart disease, and hypertension. We used a dense whole-genome scan of DNA samples from the Framingham Heart Study participants to identify a common genetic variant near the INSIG2 gene associated with obesity. We have replicated the finding in four separate samples composed of individuals of Western European ancestry, African Americans, and children. The obesity-predisposing genotype is present in 10% of individuals. Our study suggests that common genetic polymorphisms are important determinants of obesity.     

Fertilization success and blastomere morphology as predictors of egg and juvenile quality for domesticated Atlantic cod,Gadus morhua,broodstock

We investigated if simplified routines based on blastomere morphology and fertilization success can be used as predictors of egg and embryo viability in Atlantic cod, and abnormal blastomere morphology is related to juvenile deformities. Egg morphology data from 312 families that were produced by hand stripping of gametes were used. Fertilized eggs from all families were separately incubated in 25 L incubators. Blastomere morphology and fertilization success were assessed at 16–32 cell stage. Embryo mortality was measured until hatch. Fertilization success showed a significant positive correlation with the proportion of normal blastomere and 74% of the variation in the incidence of blastomere abnormality was explained by fertilization success. Juvenile deformities were positively correlated with blastomere abnormality and 8% of the variation in juvenile deformities was explained by incidences of blastomere abnormality. To our knowledge, this is the first direct evidence showing that incidences of blastomere abnormalities may be related to cod juvenile deformities. Our results suggest that fertilization success and the occurrence of blastomere abnormalities could be easily adopted by commercial cod hatcheries for the early determination of egg quality.     

Tolerance of un‐ionized ammonia in live feed cultures of the calanoid copepod Acartia tonsa Dana

Optimal water quality is considered as being a restriction for marine copepod cultures for live feed. There is a lack of knowledge on the water‐quality conditions in copepod cultures and the effect on copepods. Few studies have investigated the effect of ammonia on copepods, and fewer reports No Observed Effect Concentrations (NOEC) and Lowest Observed Effect Concentrations (LOEC), which provides safety levels before cultures are affected. This study investigates the tolerance of Acartia tonsa nauplii and adults to ammonia, using mortality as the endpoint after 24, 48 and 72 h of exposure. Nauplii were exposed to levels from 0 to 5127 μg NH₃ L^?1 and adults to levels from 0 to 8481 μg NH₃ L^?1. Nauplii NOEC was 30 μg NH₃ L^?1 and LOEC was 81 μg NH₃ L^?1. Adult NOEC was 477 μg NH₃ L^?1 and LOEC was 1789 μg NH₃ L^?1. 50% Lethal Concentrations (LC₅₀) for nauplii of 48 and 72 h was 1257 and 220 μg NH₃ L^?1. LC₅₀ for adults was 2370 (24 h), 972 (48 h) and 770 (72 h). Combining NOEC with excretion rates of NH₄/NH₃ a model was developed to calculate densities in batch cultures. We recommend that for batch cultures of A. tonsa, NH₃ is kept below NOEC for nauplii and that levels of NH₃ together with pH are monitored weekly.     

Where water is oxidized to dioxygen: structure of the photosynthetic Mn4Ca cluster

The oxidation of water to dioxygen is catalyzed within photosystem II (PSII) by a Mn(4)Ca cluster, the structure of which remains elusive. Polarized extended x-ray absorption fine structure (EXAFS) measurements on PSII single crystals constrain the Mn(4)Ca cluster geometry to a set of three similar high-resolution structures. Combining polarized EXAFS and x-ray diffraction data, the cluster was placed within PSII, taking into account the overall trend of the electron density of the metal site and the putative ligands. The structure of the cluster from the present study is unlike either the 3.0 or 3.5 angstrom-resolution x-ray structures or other previously proposed models.     

Associations between dairy herd management factors and bulk tank milk antibody levels against Ostertagia ostertagi

A cross-sectional questionnaire survey was performed on dairy herds in Flanders (Belgium) to detect management factors that are associated with an increased gastrointestinal parasite infection level of adult dairy cows. At the end of the grazing season, information concerning general herd factors, pasture management and anthelmintic treatment strategy was obtained from 956 herds. A bulk tank milk sample was obtained from 779 out of the 956 herds and the antibody levels (ODR) against Ostertagia ostertagi were determined. The associations between ODR and herd management factors were studied by two linear regression models. The first model evaluated the effect of general herd factors and the level of the cows' exposure to pasture. Large sized herds had significantly lower ODRs as compared to medium (P=0.001) or small sized herds (P=0.03). Herds with only dairy cows had lower ODRs than herds with both dairy and beef cows (P=0.02). An increased exposure to pasture of the cows was associated with higher ODRs (P<0.001). The second model was built to evaluate the effect of pasture management factors and anthelmintic treatment strategy. Later turn-out on pasture (P<0.001) and mowing (P=0.002) were both significantly associated with lower ODRs. Cows that had a restricted grazing time per day tended to have lower ODR than cows that grazed 24 h per day (P=0.07). An increased exposure to pasture of the heifers was significantly associated with higher ODRs (P=0.001). No associations were found between ODR and calf related management factors, anthelmintic treatment strategy, time of turn-in, rotational grazing type or stocking rate. Later turn-out on pasture, mowing and restricting the grazing time per day are factors that can be applied immediately on dairy farms to reduce economical losses due to gastrointestinal nematodes.