Comparison of litter decomposition in a natural versus coal‐slurry pond reclaimed as a wetland

Decomposition is a key function in reclaimed wetlands, and changes in its rate have ramifications for organic‐matter accumulation, nutrient cycling, and production. The purpose of this study was to compare leaf litter decomposition rates in coal‐slurry ponds vs. natural wetlands on natural floodplain wetlands in Illinois, USA. The rate of decomposition was slower in the natural wetland vs. the coal pond (k = 0·0043 ± 0·0008 vs. 0·0066 ± 0·0011, respectively); the soil of the natural wetland was more acidic than the coal pond in this study (pH = 5·3 vs. 7·9, respectively). Similarly, higher organic matter levels were related to lower pH levels, and organic matter levels were seven‐times higher in the natural wetland than in the coal pond. The coal slurry pond was five years old at the time of the study, while the natural oxbow wetland was older (more than 550 years). The coal‐slurry pond was originally a floodplain wetland (slough); the downstream end was blocked with a stoplog structure and the oxbow filled with slurry. The pattern of decomposition for all species in the coal pond was the same as in the natural pond; Potomogeton nodosus decomposed more quickly than Phragmites australis, and both of these species decomposed more quickly than either Typha latifolia or Cyperus erythrorhizos (k = 0·0121±0·0008, 0·0051 ± 0·0006, 0·0024 ± 0·0001, 0·0024 ± 0·0004, respectively). Depending on how open or closed the system is to outside inputs, decomposition rate regulates other functions such as production, nutrient cycling, organic‐layer accumulation in the soil, and the timing and nature of delivery of detritus to the food chain. Copyright © 2004 John Wiley & Sons, Ltd.     

Femoral component failure in canine cemented total hip replacement: a report of two cases

Femoral stem fracture is reported as an uncommon late complication of cemented total hip replacement in two dogs. In each case surgical salvage was achieved by extirpation of the proximal unstable component of the femoral stem, resulting in acceptable limb function. To the authors' knowledge, intramedullary femoral stem failure has not been previously reported after cemented total hip replacement in the dog. Factors believed to have contributed to implant failure in these dogs are discussed and compared with the same complication in humans.     

Use of a tetanus toxoid marker to allow differentiation of infected from vaccinated poultry without affecting the efficacy of a H5N1 avian influenza virus vaccine

Tetanus toxoid (TT) was assessed as a positive marker for avian influenza (AI) virus vaccination in chickens, in a vaccination and challenge study. Chickens were vaccinated twice with inactivated AI H5N2 virus vaccine, and then challenged three weeks later with highly pathogenic AI H5N1 virus. Vaccinated chickens were compared with other groups that were either sham-vaccinated or vaccinated with virus with the TT marker. All sham-vaccinated chickens died by 36 hours postinfection, whereas all vaccinated chickens, with or without the TT marker, were protected from morbidity and mortality following exposure to the challenge virus. Serological testing for H5-specific antibodies identified anamnestic responses to H5 in some of the vaccinated birds, indicating active virus infection.     

The influence of seasonal environmental changes on ontogenetic migrations of the squid Loligo gahi on the Falkland shelf

The Patagonian longfin squid Loligo gahi undertakes horizontal ontogenetic migrations on the Falkland shelf: juveniles move from spawning grounds located in shallow, inshore waters (20–50 m depths) to feeding grounds near the shelf edge (200–350 m depths). Immature squid feed and grow in these offshore feeding grounds and, upon maturation, migrate back to inshore waters to spawn. The possible influence of environmental factors on L. gahi migrations was investigated using data from oceanographic transects, crossing the region of known L. gahi occurrence. They were made from the inshore waters of East Falkland eastwards to depths of 1250 m on a monthly basis from 1999 to 2001. Four main water types were found in the region: Shelf, Sub‐Antarctic Superficial and Antarctic Intermediate water masses, and Transient Zone waters. The inshore spawning grounds occur in the Shelf Water mass, whereas the feeding squid (medium‐sized immature and maturing individuals) were associated with the Transient Zone. The 5.5°C isotherm appeared to mark the limit of squid distribution into deeper waters in all seasons. Seasonal changes in water mass characteristics and location were found to be important for seasonal changes in L. gahi migrations on the Falkland shelf.     

Fatty acids of the lipids of cultured herring

The composition of fatty acids was determined in neutral lipids and phospholipids from cultured herring reared on a diet based on squid muscle. The phospholipids retained the fatty acid pattern characteristic of marine fish. In contrast, the fatty acids of neutral lipids tended to reflect the fatty acid spectrum in the diet, and were very different from the characteristic pattern of herring oils. It was concluded that the cultured herring had little ability to modify dietary fatty acids and that the enzymes of phospholipid metabolism possess considerable specificity for certain fatty acids.