Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Plankton trace elements

Other limitations on phytoplankton growth are chemical in nature. Nitrogen, in the form of nitrate, nitrite and ammonium ions, forms a basic building material of a plankton s cells. In some species silicon, as silicate, takes on this role. Phosphorus, in the form of phosphate, is in both cell walls and DNA. Iron, in the form of Fe(III) hydroxyl species, is an important trace element. Extensive areas of the mixed layer of the upper ocean have low nitrate and phosphate levels during... [Pg.20]

In contrast to their rather low dissolved concentrations in seawater, some of the trace metals, e g., iron and aluminum, along with oxygen and silicon, comprise the bulk of Earth s crust. Some trace elements are micronutrients and, hence, have the potential to control plankton species composition and productivity. This provides a connection in the crustal-ocean-atmosphere fectory to the carbon cycle and global climate. [Pg.259]

On the basis of chemical profile, Wood (38) predicted that arsenic, selenium, and tellurium will be methylated in the environment, and lead, cadmium, and zinc will not. Elemental concentration in the aquatic food chain has been reported for As (39), Hg (40), Cd (41), Pb (42), and Cu (43). The biological half-life of methylmercury in fish, for example, is one to two years (44). Pillay et al. (40) implicated heavy coal burning in the mercurial contamination of plankton and fish populations of Lake Erie. Other metals, notably cadmium, have been shown to be incorporated into the grazing grasses surrounding a coal burning source (27). Trace element contamination, therefore, can enter the food chain at various points. Disposal of solid wastes in the form of ash and slag is yet another environmental consideration (45). [Pg.204]

More immediate goals differ from one scientific discipline to another. One goal of which I am most aware is the prediction of the role of aqueous speciation on the bioavailability and toxicity of trace elements to plankton and estuarine detritusfeeding invertebrates. In the longer range, these studies would be extended to include the various aquatic organisms higher in the... [Pg.7]

The organic biomarker proxy for past sea surface temperatures ( U37 ) came to paleoceano-graphy from an unexpected direction. Nearly aU paleoceanographic tools rely on some aspect of the fossilized hard parts of marine organisms. Thus, assemblages of calcareous microplankton such as foraminifera and coccoliths, or of siliceous plankton such as radiolaria and diatoms, provided the basis for the CLIMAP reconstruction of the Ice Age ocean (CLIMAP, 1976, 1981). Additionally, a host of chemical methods relies on the same hard parts to furnish isotopic and trace element... [Pg.3238]

The contents of some trace elements in the continental crust, shales, soils, bituminous coals and plankton are given in Table 1.1 to provide some perspective when considering other aspects of these elements. In each of these situations, organic matter is associated with the elements to a greater or a lesser degree. This is not usually very marked with crustal rocks except shales, but may be a major factor for some elements in surface soils and coals. The data in Table 1.1 show that, for some elements, e.g. beryllium, cadmium, cobalt and molybdenum, the contents of the various reservoirs are similar, while for others, there may be enrichments relative to the crust, e.g. boron and sulfur in many shales, soils and coals, mercury, nickel and selenium in many shales, and germanium in some coals. [Pg.3]

Krill is a small planktonic crustacean primarily living in the Southern Ocean and its total biomass is estimated to be at least 500 million tons (around 500,000 billion individuals). It feeds on phytoplankton and is one of the most important species in the Antarctic food chain. In fact, krill is the basic food for whales, seals, cephalo-pods, penguins and many other seabirds and is also used for direct human consumption (20-24). Moreover, krill seems to be a promising bioindicator of environmental pollution by trace elements and organic compounds. All these considerations called for the production of a CRM for trace elements based on this matrix (25). [Pg.280]

SUMMARY OF TECHNIQUES OF FINAL DETERMINATION USED IN THE CERTIFICATION OF TRACE ELEMENTS IN PLANKTON CRM 414... [Pg.294]

Hathorne, E. C. 2004. The Trace Element and Lithium Isotope Composition of Planktonic Foraminifera. PhD thesis. The Open University, p. 247. [Pg.29]

Planktonic foraminifer tests are widely used to investigate palaeoenvironmental signals from the surface oceans by the analysis of their isotope ratios and trace element composition. Obviously if a past environmental signal is to be reliably reconstructed it is necessary either that the tests have survived with little or no diagenetic alteration or, if diagenetic alteration has occurred, that it has not greatly affected the test chemistry. If systematic diagenetic biases operate on foraminifer tests then they may lead to misinterpretation of past conditions. [Pg.59]

Examples of applications of X-ray spectrometric analytical techniques to elemental determinations in a variety of materials are presented in Table 2.12. Some recent applications papers may be mentioned. Total reflection XRF has been applied by Xie et al. (1998) to the multielement analysis of Chinese tea (Camellia sinensis), and by Pet-tersson and Olsson (1998) to the trace element analysis of milligram amounts of plankton and periphyton. The review by Morita etal. (1998) on the determination of mercury species in environmental and biological samples includes XRF methods. Alvarez et al. (2000) determined heavy metals in rainwaters by APDC precipitation and energy dispersive X-ray fluorescence. Other papers report on the trace element content of colostrum milk in Brazil by XRF (da Costa etal. 2002) and on the micro-heterogeneity study of trace elements in uses, MPI-DING and NIST glass reference materials by means of synchrotron micro-XRF (Kempenaers etal. 2003). [Pg.1594]

Pettersson RP and Olsson M (1998) A nitric acid-hydrogen peroxide digestion method for trace element analysis of milligram amounts of plankton and periphyton by total-reflection X-ray fluorescence spectrometry. J Anal Atom Spectrom 13 609-613. [Pg.1632]

All trace elements are taken up intracellularly by specialized transport proteins (enzymes) on the outer membrane of plankton cells. Consequently, uptake rates generally follow Michaelis-Menten enzyme kinetics ... [Pg.22]

S. Woelfl, M. Mages, S. Mercado, L. Villalobos, M. Ovari, and F. Encina. Determination of trace elements in planktonic microcrustaceans using total reflection X-ray fluorescence (TXRF) First results from two Chilean lakes. Analytical and Bioanalytical Chemistry 378 1088-1094,2004. [Pg.308]

Arslan, Z. (2000). Development of analytical methods for determination of trace elements in marine plankton by atomic absorption and inductively coupled plasma mass spectrometry. Unpublished Ph.D. Thesis, University of Massachusetts, Amherst. [Pg.191]


See other pages where Plankton trace elements is mentioned: [Pg.102]    [Pg.6]    [Pg.82]    [Pg.171]    [Pg.278]    [Pg.280]    [Pg.284]    [Pg.288]    [Pg.103]    [Pg.67]    [Pg.68]    [Pg.1654]    [Pg.2887]    [Pg.3104]    [Pg.3214]    [Pg.241]    [Pg.15]    [Pg.292]    [Pg.292]    [Pg.295]    [Pg.165]    [Pg.46]    [Pg.440]    [Pg.905]    [Pg.64]    [Pg.12]    [Pg.18]    [Pg.26]    [Pg.26]    [Pg.553]    [Pg.448]   
See also in sourсe #XX -- [ Pg.4 , Pg.347 ]




SEARCH



Plankton

Planktonic

© 2024 chempedia.info