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991.
Gene de Castro 《Marine Policy》1977,1(4):342-343
A summary of the various forms of pollution control discussed at an international Anti-Pollution Course held at the French Merchant Marine School in Marseilles on 13–25 June 1977. 相似文献
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Evidences of temperature-controlled dense water cascading off the Gulf of Lion shelf, in the northwestern Mediterranean, and several Aegean shelves in the northeastern Mediterranean are reported. Together with the Adiatic shelf, already listed by Ivanov, Shapiro, Huthnance, Aleynik, & Golovin (2004), these zones represent the major coastal areas of the Mediterranean Sea where dense water is produced. 相似文献
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Seasonal dynamics of ciliated protozoa and their potential food in an eutrophic estuary (Bay of Biscay) 总被引:2,自引:0,他引:2
Iaki Urrutxurtu Emma Orive Alejandro de la Sota 《Estuarine, Coastal and Shelf Science》2003,57(5-6):1169-1182
Ciliate assemblages, together with phytoplankton and heterotrophic nanoflagellates (HNF) as their potential food, have been surveyed monthly along the salinity gradient of the Nervión River estuary from March 2000 to March 2002. A total of 135 taxa of ciliate have been identified corresponding to 20 orders. Scuticociliates, naked choreotrichs and oligotrichs were the most abundant groups, distributed throughout a broad range of salinity. In addition to these groups, which were the dominant taxa in the middle estuary, tintinnids were characteristic of the ciliate assemblages of the outer estuary whereas in the innermost part naked choreotrichs and oligotrichs decreased in number, being substituted by sessilids, hymenostomatids, peniculids and cyrtophorids. Total ciliate concentrations were among the highest reported in the literature for other estuaries and coastal waters, frequently reaching 105 cells l−1. Meanwhile, tintinnid concentrations were comparable with those of other estuarine and coastal waters. Based on a principal component analysis (PCA) three main groups were delineated, with ciliates and their potential food sources as variables. One was that constituted by freshwater ciliate such as sessilids, hymenostomatids, cyrtophorids and pleurostomatids, which appear in low numbers in the innermost part, mainly in winter. Another group contained diatoms, chlorophytes, flagellates, euplotids and scuticociliates, all of them broadly distributed along the estuary and reaching their maximum density in late spring–summer. The third group was made up of taxa mainly appearing at the seaward end such as dinoflagellates, cyanobacteria, haptorids, tintinnids, naked choreotrichs and oligotrichs, which reached the highest densities in summer and early autumn. Ciliates do not seem to be food limited in the Nervión River estuary or much controlled by metazoan grazing. 相似文献
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H.J.W. de Baar 《Progress in Oceanography》1994,33(4)
The Law of the Minimum was originally formulated by Justus von Liebig, as one of the 50 interlinked laws concerned with agriculture. The original writings of J. von Liebig often were misinterpreted by his successors. Brandt (1899) took this one law out of its context and proposed that limitation by nitrogen is a dominant factor in plankton ecology, far beyond its original application to agriculture. This was opposed by Nathansohn (1908) who suggested instead a dynamic balance of growth and loss terms. Towards validating, or eventually falsifying Brandt's hypothesis, Atkins, Harvey, Cooper and others developed the chemical methods necessary for re-defining ocean nutrient cycling and growth limitation. The major exception to these modern perspectives was the Antarctic Paradox of high nutrients and low chlorophyll which inspired Gran, Atkins, Harvey and Cooper to pioneer the concept of iron limitation. An exhaustive overview is given of efforts to define Fe in seawater and its controlling effect on in situ plankton growth, for the 1920–1984 period. Somewhat parallel work in the laboratory on single species of algae in chelation-controlled media has provided much insight, but is sketched only briefly. Martin and contemporaries developed the chemical methods necessary for defining the ocean chemistry of Fe and its role for in situ growth. These developments are sketched for the 1982–1991 period. Once again the Law of the Minimum and associated bold hypotheses served, albeit briefly, to bring a nutrient element in the forefront of research. This, and the recent awareness of CO2 as rate limiting factor, underline the conclusion that advances in sciences often hinge on advances in technology, confirming Kuhn (1962). In this case the new analytical techniques developed by Atkins, Harvey, Cooper, Martin and their associates have proven revolutionary for plankton ecology. Some observations in plankton ecology may be reminiscent of the agricultural Law of the Minimum, but this would not warrant its direct application, beyond its original context and agriculture, to plankton ecology. Rather the net rate of increase of phytoplankton is the dynamic balance of multiple growth and loss terms, together also determining the biomass at given time and space. 相似文献