Book review of TURBULENCE – AN INTRODUCTION FOR SCIENTISTS AND ENGINEERS by P.A. Davidson,Oxford University Press, 2004, XIX + 657 pp., £90.00, $174.50 hardback (ISBN 0-19-852948-1), £35.00, $69.50 paperback (ISBN 0-19-852949-X).

Abstract

By T. G. Cowling. Adam Hilger Ltd, x + 136 pp. £10.00 (ISBN O 85274 300 9) July 1976.     

A regression model using sediment chemistry for the evaluation of marine environmental impacts associated with salmon aquaculture cage wastes

This study was undertaken to develop an approach for modelling changes of sediment chemistry related to the accumulation of aquaculture waste. Metal composition of sediment Al, Cu, Fe, Li, Mn, and Zn; organic carbon and < 63 microm particles were used to determine the extent of detectable effects around the cage. This study showed marked differences in the sediment chemistry between aquaculture sites and the natural background: (1) negative correlations between sediment Cu and Zn with Al, (2) poor correlations between metals and Li, and (3) concentrations of Fe and Mn decreased with increased accumulation of organic carbon. There is a trend among normalised metals, organic carbon and particles related to normal, hypoxic and anoxic sediment conditions. The trends are useful for detecting and assessing the cumulative effects from aquaculture wastes to the marine environment. Lithium is less interactive with other metals in aquaculture sediments compared with the natural background sediments. Principal components analysis (PCA) was carried out on the metals, organic carbon, and particles to cluster the similarities of the variables so as to establish the predicted or adjusted environmental monitoring program (EMP) ratings. This approach, using the adjusted EMP rating based on sediment chemistry, yields a regression model with R2 = 0.945 compared to R2= 0.653 for the regression model using unadjusted EMP for assessing the environmental conditions.     

Distribution of contaminants in biota and sediments in the Musquash Estuary, Atlantic Canada, marine protected area site initiative and contaminant exclusion zone

The Musquash Estuary, one of the last ecologically intact estuaries in New Brunswick, has been designated an area of interest for a marine protected area (MPA) under the Oceans Act. The area has been assessed for contaminant background levels as required for establishing MPA environmental quality. American lobster (Homarus americanus), blue mussel (Mytilus edulis) and sediments were collected for assessing contaminant levels and distribution in the harbour. Levels of contaminants from the indicator species and the abiotic component have shown: (1) two extremes of high and low Cu and Ag in lobster from the area; and (2) lower metal levels in inner Musquash Harbour sediments and mussels than in those from the harbour mouth. These suggest that deposition of contaminants into the Musquash MPA site was due to transport of contaminants by coastal currents from upstream coastal industrial activities. This reverse trend with higher contaminant levels in the biotic and abiotic components in the outer harbour than in the inner harbour differs from a contaminated harbour and suggests that a contaminant exclusion zone should be considered for controlling contamination from nearby coastal and estuarine industrial sites to protect the sensitive habitats within the marine protected area.     

Metal contaminants for modelling lobster (Homarus americanus) migration patterns in the Inner Bay of Fundy, Atlantic Canada

A method, which uses metal compositions in lobster digestive glands as natural environmental tags, has been developed to trace lobster movements. Lobsters were collected from three selected sites, Minas Channel, Minas Basin, and Cobequid Bay, Inner Bay of Fundy, New Brunswick, Canada, that were known to be contaminated with Cu. Five metal variables (Ag, Cd, Cu, Mn and Zn) were processed for principal component analysis (PCA). Metal concentration and burden models were investigated and PCA was able to differentiate lobsters from the respective catch sites. The method was applied to investigate the May and June lobsters collected at the three sites to determine the migration rate during this period of the fishing season. The results show a high level of mixing at Minas Basin and Cobequid Bay in June, and lobster movement inward toward the inner reaches of the bay, with very limited movement outward from the inner bay.     

Aquaculture-related trace metals in sediments and lobsters and relevance to environmental monitoring program ratings for near-field effects

The study was undertaken to assess the marine environmental effects from feed and waste associated with aquaculture activities. Metal compositions of sediment, lobster, and feed were used to evaluate the extent of detectable effects at 0 m (under the cage) and 50 m distance. Sediments that were collected under the cages and were characterised as hypoxic or anoxic, showed elevated levels of Cu, Zn, organic carbon, and % <63 microm particles, and low Mn and Fe. At 50 m there was a major reduction in waste chemical impact. Using lobster, a bioindicator species, as a tool for detecting near-field impacts, showed accumulations of high Cu associated with active aquaculture sites. Chemical compositions and metal ratios normalised with organic carbon, were used to assess the sediment conditions associated with environmental monitoring program ratings (EMP--normal, hypoxic, and anoxic). Principal component analysis (PCA) was used to explore chemical data at all sites for differentiating normal, hypoxic and anoxic sediment conditions. Selected variables (Cu, Zn, Fe, Mn, organic carbon, and particles <63 microm) were sufficient for the PCA approach with >90% explainable variance of first two components. The groupings based on PCA and cluster analysis were similar to EMP classifications with some exceptions of mis-identification by EMP. The sediment chemistry components were valid indicators for evaluating marine environmental conditions and for assessing aquaculture operating sites. The developed techniques, using chemical variables in combination with EMP and the statistical approach should be useful to predict the effects of aquaculture practices and the suitability of aquaculture operations.     

运用LANDSAT ETM+和ASTER数据进行岩性分类

本文评价了运用ASTER和LANDSAT ETM+数据进行岩性制图的性能。分别利用ASTER数据不同波段区图像及其组合,以及ETM+数据进行岩性分类,并探讨了将ASTER和ETM+数据叠加在一起进行了岩性分类; 利用现有地质图对所有分类结果进行了定量评价。结果表明,ASTER数据不同波段的岩性识别能力不同,并且较ETM+数据能更准确地识别岩性。更重要的是,把ASTER与ETM+数据结合在一起进行岩性分类,可获得比用任一数据单独分类更高的分类精度,表明二者的光谱特征具有一定的互补性。