Magnetic cleansing of weathered/tarry oiled feathers--the role of pre-conditioners

Iron powder has previously been demonstrated to be effective in the removal, via magnetic harvesting, of a wide variety of oil contaminants from feathers and plumage. This study investigates the efficacy of magnetic cleansing for the removal from feathers of tarry contamination that has been allowed to weather. Clusters of feathers from Mallard duck (Anas platyrhnchos) and Little Penguin (Eudyptula minor) were completely immersed in a tarry contaminant and allowed to weather from one to fourteen days. The contaminant was removed using a magnetic cleansing protocol and the removal efficacy assessed gravimetrically. For one, seven and fourteen days of weathering, a final removal (after fourteen treatments) of more than 99% and 97% was achieved for duck feathers and penguin feathers, respectively. Repeating the experiments (for a seven-day weathering period) for both duck and penguin feathers, with the judicious application of a pre-conditioner (olive oil), further improved removal efficacy. A convenient method to screen for improved pre-conditioning agents is suggested.     

Whole-bird models for the magnetic cleansing of oiled feathers

Iron powder, a promising dry-cleansing agent for oiled feathers where both the contaminant and the cleansing agent may be harvested magnetically, has been tested on the plumage of whole-bird models. The breast and back plumage of Mallard Duck (Anas platyrhynchos) and Little Penguin (Eudyptula minor) carcasses were patch-contaminated with commercial-grade engine oil, three different crude oils, and an oil/seawater emulsion. The plumage was then subjected to a magnetic cleansing protocol. The contaminant removal was assessed gravimetrically and was found to reflect the outcomes for a previously reported in vitro study using feather clusters. Between 92-98% of the contaminants, and effectively all of the cleansing agent, were removed from the feathers.     

An investigation into the removal of oil from rock utilising magnetic particle technology

The application of magnetic particle technology to environmental remediation has tended to focus, up to now, upon the removal of oil contamination from plumage and fur. The present research demonstrates the potential of this technology to remove oil contamination from the surface of rock. Specifically, a single treatment has been demonstrated to remove more than 80% by weight of heavy bunker oil from the surface of a common foreshore rock type. A further three treatments have been shown to result in an optimum removal of up to 94% by weight. The results are highly reproducible and offer the possibility of achieving up to 100% removal with the appropriate use of pre-conditioners.     

Feasibility of co-culture of the Australasian sea cucumber (Australostichopus mollis) with the Pacific oyster (Crassostrea gigas) in northern New Zealand

The Australasian sea cucumber (Australostichopus mollis) has attracted commercial attention for aquaculture development, partly due to its potential for co-culture with shellfish and finfish species. However, minimal attention has been given to the possibility of co-culturing this species with oysters. In this study we evaluated the growth of juvenile sea cucumbers (36.7 ± 0.9 g, wet weight) caged underneath Pacific oyster farms in northern New Zealand. Co-culture started at the end of the summer, and after 304 days the juveniles had doubled in size (79.8 ± 3.3 g, wet weight), but their subsequent growth appeared to be constrained by overstocking of the cages and summer water temperatures, reaching a carrying capacity of 720 g m^?2. Overall, the results of this study indicate that the co-culture of juvenile sea cucumbers with Pacific oysters is feasible, if sea cucumber losses are reduced (between 33% and 52% lost in this study) and careful attention is given to stocking rates and the water temperature regimes of oyster farms in order to maintain adequate growth rates.