Episodic Release of Arsenic,Copper and Chromium from a Wood Preservation Site Monitored by Transplanted Aquatic Moss     

Rasmussen  Grete  Andersen  Sjur 《Water, air, and soil pollution》1999,109(1-4):41-52

Leaching from a wood preservation site in Norway, severely contaminated with copper (Cu), chromium (Cr) and arsenic (As), was investigated using aquatic moss. The objectives were three-fold: (i) study the release of trace metals into a river during a rainfall episode, (ii) determine whether aquatic moss can be used to detect leaching during episodic events when sampling is frequent, and (iii) determine whether aquatic moss can be used as a bioindicator in brackish water. Aquatic moss (Fontinalis antipyretica was transplanted into the river in eight moss-cages. Samples were collected during one episode of rainfall. Concentrations of As in the moss increased during the rainfall event. Cu and Cr concentrations in the moss increased during the beginning of the period, but tended to decrease because of dilution towards the end. Accumulation patterns of Cu, Cr and As in the moss varied probably because of differences in binding affinity to soil and to the moss. The use of F. antipyretica proved that leaching of trace metals do increase during a rainfall event. It was shown that aquatic moss can be used as an indicator to monitor leaching during rainfall events, however, timing of sampling is critical. Although the moss survived in brackish water, it is questioned whether ions in the water can cause competition and desorption of the metals in the moss.  相似文献   

Nonsurgical management of type II fractures of the distal phalanx in 48 Standardbred horses     

CB O''SULLIVAN  AJ DART  N MALIKIDES  RJ RAWLINSON  DR HUTCHINS  DR HODGSON 《Australian veterinary journal》1999,77(8):501-503

OBJECTIVE: To evaluate nonsurgical management of type II fractures of the distal phalanx in Standardbred horses. DESIGN: Retrospective study of 48 affected horses. RESULTS: Most fractures occurred on the lateral palmar process of the left forelimb or the medial palmar process of the right forelimb; 81% of horses were considered sound enough to return to training and 63% raced. Of those returning to racing, 41% competed in > 10 races, 37% in 2 to 10 races and 22% in only 1 race. There was no difference in performance before and after fracture. Twenty-four of 25 horses had a bar shoe fitted for > 50% of the treatment phase. Of those horses returning to training without a bar shoe, 89% refractured at the same site. Sixty percent of horses returning to training with a bar shoe raced successfully. The total convalescent time, the time rested in a box and the time spelled in a paddock were similar for horses returning to racing and those that did not. The age of the horse had no effect on the ability to return to racing. CONCLUSION: The prognosis for type II fractures of the distal phalanx is guarded. It is advisable to fit a bar shoe on the horse during convalescence. Horses returning to training and racing with a bar shoe appear less likely to refracture the distal phalanx. Those horses that return to racing can perform at a level similar to that prior to fracture.  相似文献   

Primary production of the biosphere: integrating terrestrial and oceanic components   总被引：32，自引：0，他引：32  

CB Field  MJ Behrenfeld  JT Randerson  P Falkowski 《Science (New York, N.Y.)》1998,281(5374):237-240

Integrating conceptually similar models of the growth of marine and terrestrial primary producers yielded an estimated global net primary production (NPP) of 104.9 petagrams of carbon per year, with roughly equal contributions from land and oceans. Approaches based on satellite indices of absorbed solar radiation indicate marked heterogeneity in NPP for both land and oceans, reflecting the influence of physical and ecological processes. The spatial and temporal distributions of ocean NPP are consistent with primary limitation by light, nutrients, and temperature. On land, water limitation imposes additional constraints. On land and ocean, progressive changes in NPP can result in altered carbon storage, although contrasts in mechanisms of carbon storage and rates of organic matter turnover result in a range of relations between carbon storage and changes in NPP.  相似文献   

Fullerene pipes   总被引：10，自引：0，他引：10  

J Liu  AG Rinzler  H Dai  JH Hafner  RK Bradley  PJ Boul  A Lu  T Iverson  K Shelimov  CB Huffman  F Rodriguez-Macias  YS Shon  TR Lee  DT Colbert  RE Smalley 《Science (New York, N.Y.)》1998,280(5367):1253-1256

Single-wall fullerene nanotubes were converted from nearly endless, highly tangled ropes into short, open-ended pipes that behave as individual macromolecules. Raw nanotube material was purified in large batches, and the ropes were cut into 100- to 300-nanometer lengths. The resulting pieces formed a stable colloidal suspension in water with the help of surfactants. These suspensions permit a variety of manipulations, such as sorting by length, derivatization, and tethering to gold surfaces.  相似文献   

Nutrient uptake and growth of potato: Arbuscular mycorrhiza symbiosis interacts with quality and quantity of amended biochars     

Qi Yang  Sabine Ravnskov  Mathias Neumann Andersen 《植物养料与土壤学杂志》2020,183(2):220-232

Aims : The aim of this study was to explore interactive effects between quality (types) and quantity (application rates) of biochar as well as of arbuscular mycorrhiza (AM) symbiosis on the growth of potato plants. Methods : A low P sandy loam soil was amended with 0%, 1.5%, or 2.5% (w/w) of either of 4 types of biochar, which were produced from wheat straw pellets (WSP) or miscanthus straw pellets (MSP) pyrolyzed at temperatures of either 550°C or 700°C. Potato plants grown in pots containing the soils or soil biochar mixture were inoculated with or without AM fungus (AMF), Rhizophagus irregularis. The experiment was carried out under fully irrigated semi‐field conditions and plants were harvested 101 days after planting. Results : Application of high temperature biochar decreased growth, biomass and tuber yield of potato plants, while the low temperature biochar had a similar effect on yield as plants grown without biochar amendment. Total biomass of potato plants were decreased with the increasing rate of biochar. Arbuscular mycorrhizal fungus inoculation stimulated the growth of potato plants in all organs, increased tuber biomass significantly in 1.5% MSP700 amended plants, and to a lesser degree for WSP700, MSP550, and WSP550. In addition, plant biomass gain was linearly related to N, P, and K uptake, the ratio of P to N in the leaf of plants indicated that all treatments were mainly P‐limited. A multiple linear regression using P uptake and biochar rate as independent variables explained 91% of the variation in total biomass. The single effect of AMF inoculation, type and rate of biochar affected plant N, P and K uptake similarly. While AMF inoculation significantly increased P uptake in potato plants grown in soil with WSP700 or MSP700 despite of the rate of biochar. In general, application of biochar significantly increased AMF root colonization of potato plants. Conclusions : The application of MSP550 at 1.5% combined with AMF stimulated growth of potato the most. Furthermore, the results indicated that the interactive effect of AMF inoculation, biochar type and application rate on potato growth to a large extent could be explained by effects on plant nutrient uptake.  相似文献