Associations Between Dioxins/Furans and Dioxin-Like PCBs in Estuarine Sediment and Blue Crab     

Johan Liebens  Carl J. Mohrherr  Natalie K. Karouna-Renier  Richard A. Snyder  K. Ranga Rao 《Water, air, and soil pollution》2011,222(1-4):403-419

The objective of the present study was to evaluate the relationships between the quantity, toxicity, and compositional profile of dioxin/furan compounds (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in estuarine sediment and in the blue crab (Callinectes sapidus). Sediment and blue crab samples were collected in three small urban estuaries that are in relatively close proximity to each other. Results show that differences between PCDD/F and DL-PCB mass concentrations and total toxic equivalents (TEQ) toxicity in sediments of the three estuaries are reflected in those of the blue crab. TEQs are higher in the hepatopancreas of the crabs than in the sediment, but the concentration factor is inversely proportional to the TEQ in the sediments. Congener profiles in the crabs are systematically different from those in the sediments, and the difference is more pronounced for PCDD/Fs than for DL-PCBs, possibly due to differences in metabolization rates. Compared with sediment profiles, more lesser-chlorinated PCDD/Fs that have higher TEFs accumulate in crab hepatopancreas. This selective bioaccumulation of PCDD/Fs results in a TEQ augmentation in crab hepatopancreas compared with sediments. The bioaccumulation in the blue crab is also selective for PCDD/Fs over DL-PCBs.  相似文献   

Invasions of the Portuguese millipede,Ommatoiulus moreleti,in southern Australia     

Geoff H. Baker  Linda Grevinga  Natalie Banks 《Pedobiologia》2013,56(4-6):213-218

The Portuguese millipede, Ommatoiulus moreleti, was first recorded in Australia on Eyre Peninsula, South Australia in 1953. By the early 1980s, O. moreleti had spread to several sites across southern Australia where it had become a significant nuisance pest invading houses in large numbers in autumn and spring. At that time, it was predicted that O. moreleti would further expand its distribution to occupy most areas of southern Australia with mean annual rainfall of 300–2400 mm (excluding areas with summer rain maxima), mean daily minimum air temperatures in winter of 0–15 °C and mean daily maximum temperatures in summer of 18–33 °C, based on climatic matching of where it had already spread to. This paper reports the known distribution of O. moreleti in Australia in 2013 and confirms the earlier prediction. Whilst stadial age and body size (width) of O. moreleti now vary greatly between individual sites in Australia, geographic scale patterns in these traits are slight, with both age and size only weakly correlated with rainfall and temperature. Millipedes are smaller in Australia compared with Portugal. The importance of this size variation is discussed with reference to its likely influence on fecundity and the success of an introduced biological control agent (Pelidnoptera nigripennis: Diptera, Sciomyzidae).  相似文献   

Quantification of seasonal sediment and phosphorus transport dynamics in an agricultural watershed using radiometric fingerprinting techniques   总被引：1，自引：0，他引：1  

Natalie L. H. Huisman  K. G. Karthikeyan  Jasmeet Lamba  Anita M. Thompson  Graham Peaslee 《Journal of Soils and Sediments》2013,13(10):1724-1734

Purpose

Phosphorus (P) is a limiting nutrient for most US Midwestern aquatic systems and, therefore, increases of P, through point or non-point sources (NPS) of pollution such as agriculture, causes eutrophication. Identifying specific NPS contributions (e.g., upland vs. stream channels) for sediments and P is difficult due to the distributed nature of the pollution. Therefore, studies which link the spatial and temporal aspects of sediment and P transport in these systems can help better characterize the extent of NPS pollution.

Materials and methods

Our study used fingerprinting techniques to determine sources of sediments in an agricultural watershed (the North Fork of the Pheasant Branch watershed; 12.4 km² area) in Wisconsin, USA, during the spring, summer, and fall seasons of 2009. The primary sources considered were uplands (cultivated fields), stream bank, and streambed. The model used fallout radionuclides, ¹³⁷Cs, and ²¹⁰Pb_xs, along with total P to determine primary sediment sources. A shorter-lived fallout radioisotope, ⁷Be, was used to determine the sediment age and percent new sediments in streambed and suspended sediment samples (via the ⁷Be/²¹⁰Pb_xs ratio).

Results and discussion

Upland areas were the primary source of suspended sediments in the stream channels followed by stream banks. The sediment age and percent new sediment for the streambed and suspended sediments showed that the channel contained and transported newer (or more recently tagged with ⁷Be) sediments in the spring season (9–131 days sediment age), while relatively old sediments (165–318 days) were moving through the channel system during the fall season.

Conclusions

Upland areas are the major contributors to in-stream suspended sediments in this watershed. Sediment resuspension in stream channels could play an important role during the later part of the year. Best management practices should be targeted in the upland areas to reduce the export of sediments and sediment-bound P from agricultural watersheds.  相似文献   

Water quality,waste production,and off-flavor characterization in a depuration system stocked with market-size Atlantic salmon Salmo salar     

John Davidson  Natalie Redman  Curtis Crouse  Brian Vinci 《Journal of the World Aquaculture Society》2023,54(1):96-112

Land-based Atlantic salmon, Salmo salar, grow-out facilities utilize depuration to remediate off-flavor. Water used in this process is either discharged or repurposed as supply water in recirculating aquaculture systems (RAS). Both approaches require an understanding of water quality and waste production for water treatment decisions and compliance with pollution discharge standards; however, these data were lacking. Therefore, a study was carried out to characterize these parameters. To begin, 311 salmon (5–6 kg) originally cultured in freshwater RAS were stocked at 100 kg/m³ in an 18 m³ depuration tank. Feed was withheld 1 day before transfer and throughout the 7-day study period. Hours after stocking, total suspended solids (TSS), total phosphorus (TP), and total ammonia nitrogen (TAN) levels spiked, and concentrations declined thereafter. Delta TSS and TP were negligible by the end of the trial; however, TAN plateaued, indicating that salmon began to catabolize somatic tissue in the absence of feeding. Geosmin and 2-methylisoboreol levels in water and fish were low throughout the study. This research indicates that residual waste production occurs while depurating Atlantic salmon. Procedural refinements and recommendations were gleaned including locality for introducing depuration system water within RAS and extension of the feed withholding period before depuration.  相似文献   

Mycobacterium fortuitum abortion in a sow     

Allysa L. Cole  Natalie M. Kirk  Leyi Wang  Chien-Che Hung  Jonathan P. Samuelson 《Journal of veterinary diagnostic investigation》2022,34(1):116

Two aborted Chester White pig fetuses were presented to a veterinary diagnostic laboratory in Illinois. Postmortem examination identified no gross abnormalities. Histologic evaluation revealed multifocal necrosis of chorionic epithelial cells, coalescing areas of mineralization in the placenta, and focal accumulations of viable and degenerate neutrophils in the lung. Intra- and extracellular acid-fast bacilli were identified in the lesions in both the placenta and lungs. Bacterial culture of stomach contents yielded heavy growth of Mycobacterium fortuitum, a rapidly growing nontuberculous mycobacterium (NTM), which was further confirmed through whole-genome sequencing. NTM are opportunistic pathogens commonly found in the soil and in contaminated water supplies. In animals, M. fortuitum is typically introduced through cutaneous wounds leading to infections limited to the skin, with systemic infection being uncommon. To our knowledge, abortion caused by M. fortuitum has not been reported previously.  相似文献   

A meta-analysis review of the effects of recombinant bovine somatotropin: 1. Methodology and effects on production   总被引：1，自引：0，他引：1       下载免费PDF全文

I. R. Dohoo  K. Leslie  L. DesCteaux  A. Fredeen  P. Dowling  A. Preston    W. Shewfelt 《Canadian journal of veterinary research》2003,67(4):241-251

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Treatment of subclinical mastitis.     

J W Tyler  R C Wilson  P Dowling 《Veterinary Clinics of North America: Food Animal Practice》1992,8(1):17-28

Topics addressed in this article include applied pharmacology of the bovine mammary gland, principles of antibiotic sensitivity testing, mechanisms of antimicrobial resistance, causes of treatment failures, diagnostic considerations, and therapy of specific subclinical mastitis syndromes. Recent research concerning systemic therapy of subclinical mastitis is highlighted and critically reviewed. Limitations of antibiotic sensitivity testing are discussed. The lack of proven, efficacious therapy for many subclinical mastitis syndromes is emphasized.  相似文献   

Role of Grazing Intensity on Shaping Arbuscular Mycorrhizal Fungi Communities in Patagonian Semiarid Steppes     

Natalie Dudinszky  M.N. Cabello  A.A. Grimoldi  S. Schalamuk  R.A. Golluscio 《Strength and Conditioning Journal》2019,72(4):692-699

Arbuscular mycorrhizal fungi (AMF) are vital for maintaining ecosystem structure and functioning and can be affected by complex interactions between plants and herbivores. Information found in the literature about how ungulate grazing affects AMF is in general contradictory but might be caused by differences in grazing intensities (GIs) among studies. Hence we studied how different GIs affect the composition, diversity, and abundance of AMF communities in a semiarid steppe of Patagonia. We predicted that 1) total AMF spore abundance (TSA) and diversity would decrease only under intense-grazing levels and 2) AMF species spore abundance would depend on their life-history strategies and on the GI. To test our predictions, we compared AMF communities among nongrazed (NG), moderately grazed (MG, 0.1–0.3 sheep ha¹), and intensely grazed sites (IG, > 0.3 sheep ha¹). GI was the most important factor driving changes in TSA and diversity, regardless of host plant identity. TSA, diversity, and evenness significantly decreased in IG sites but were not affected by MG. AMF species spore abundance varied depending on their life-history strategies and GI. Families with high growth rates like Glomeraceae and probably Pacisporaceae showed the highest spore abundance in all sites but decreased under IG. Species with higher carbon demands like Gigasporaceae showed low spore abundance and frequency in NG and MG sites and were absent in IG sites. In contrast, species with low growth rates, but efficient carbon usage, like Acaulosporaceae, showed low spore abundance in all sites but increased in IG sites compared with NG or MG sites. We conclude that intensification of grazing reduces AMF diversity and abundance, with the likely loss of AMF benefits for plants, such as improved nutrient and water uptake and soil aggregation. Therefore, sustainable grazing systems should be designed to improve or restore AMF communities, particularly in degraded rangelands, like the Patagonian steppes.  相似文献   

Disentangling the identities and distribution patterns of the introduced beachfleas Orchestia gammarellus and Platorchestia platensis (Crustacea: Amphipoda: Talitridae) in South Africa     

Natalie Diemer  Alan Hodgson 《African Zoology》2016,51(4):203-210

Two introduced beachfleas, Orchestia gammarellus and Platorchestia platensis, have been recorded from South Africa, but have been misidentified by some earlier researchers and, prior to this study, each was also known from just a few, scattered observations, such that their true distributions remained obscure. We illustrate both species to clarify the features that identify and distinguish them and determine their true distributions by re-examining historical samples and by collecting new material from estuaries and lagoons along the west and south coasts of South Africa. Adult males of O. gammarellus have slender antennae and characteristic expanded, flattened, oar-like distal segments on pereopod 7. Adult males of P. platensis have the peduncle of antenna 2 strongly swollen and have bulbous, but not flattened, distal segments on pereopod 7. Both species occur under wrack and other debris along the banks of estuaries and sheltered lagoons. Orchestia gammarellus is found only along the south-west coast, in the Berg River Estuary, Langebaan Lagoon and the Diep River Estuary. Previous records from Knysna were misidentifications of P. platensis. Platorchestia platensis is found at one west coast site, Langebaan Lagoon, but is widely distributed from Cape Point eastwards to at least Algoa Bay. Both species share the same habitats as several other native beachfleas and competitive interactions between native and introduced species merit investigation.  相似文献   

Agreement of serum allergen test results with unblocked and blocked IgE against cross‐reactive carbohydrate determinants (CCD) and intradermal test results in atopic dogs     

Natalie K. Y. Gedon  Teresa M. S. A. Boehm  Christoph J. Klinger  Laura Udraite  Ralf S. Mueller 《Veterinary dermatology》2019,30(3):195-e61

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