Trace metal

About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.

Micronutrient effects on cyanobacterial growth and physiology

Abstract: Trace metals play crucial roles in the carbon and nitrogen metabolism of cyanobacteria. Physiological responses to metal limitation and toxicity in culture have shown that iron is important for photosynthesis and energy distribution in the cell while both iron and molybdenum are biochemically involved in nitrate reduction and nitrogen fixation. Nitrogen fixation is also relatively sensitive to copper toxicity. Consequently, factors that affect the supply rate, chemical speciation, or the recycling of trace metals can alter patterns of primary productivity and nitrogen metabolism. Overall, three trace metal dependent processes may contribute towards dominance: efficient use of limiting light, nitrogen fixation, and production of extracellular iron binding compounds.

Bioaccumulation of heavy metals by bivalves from Lim Fjord (North Adriatic Sea)

Abstract: Trace metal concentrations (Zn, Cd, Pb and Cu) were studied in two different bivalve species of the same age, the mussel Mytilus galloprovincialis, Lmk., and the oyster Ostrea edulis, Linnaeus, which had been grown in the water of Lim Fjord, North West Yugoslavia (Peninsula Istria), i.e. under the same physicochemical conditions. The study offers a realistic view on the metal accumulation ability of oysters and mussels. The distribution of trace metals over the different organs and the edible parts of the mussels and oysters, collected in June 1979, was determined and is discussed in detail. The results are supported by the determination of the trace metal levels in the dissolved state and in the suspended material in the ambient sea water of the bivalves. Concentration factors for zinc, cadmium, lead and copper in the mussels of: 95 000, 9 100, 1 500 and 4 000; and in the oysters of: 95 500, 30 400, 3 400 and 64 500 were found, respectively. The values were evaluated comparing the metal concentration in the bivalve soft part and the dissolved trace metal levels in the adjacent water.

Sources and fluxes of atmospheric trace elements to the Gulf of Aqaba, Red Sea

Abstract: 683, and 16.7 ng m � 3 ) are about 2–3 times higher than those reported for the neighboring Mediterranean area. This is indicative of the dominance of the mineral dust component in aerosols over the Gulf. Anthropogenic impact was lower in comparison to the more heavily populated areas of the Mediterranean. During the majority of time (69%) the air masses over the Gulf originated from Europe or Mediterranean Sea areas delivering anthropogenic components such as Cu, Cd, Ni, Zn, and P. Airflows derived from North Africa in contrast contained the highest concentrations of Al, Fe, and Sr but generally lower Cu, Cd, Ni, Zn, and P. Relatively high Pb, Ni, and V were found in the local and Arabian airflows suggesting a greater influence of local emission of fuel burning. We used the data and the measured trace metal seawater concentrations to calculate residence times of dissolved trace elements in the upper 50 m surface water of the Gulf (with respect to atmospheric input) and found that the residence times for most elements are in the range of 5–37 years while Cd and V residence times are longer.

Variation with depth and season in metal sulfides in salt marsh soils

Abstract: Seasonal monitoring of metal sulfides was carried out in four soils of the Ria de Ortigueira salt marshes. Soils from the high salt marsh (with suboxic redox conditions at the surface), had low concentrations of iron sulfides (AVS and pyrite fraction) and thus a low degree of trace metal pyritiza- tion (DTMP) in surface layers (0-10 cm), but concentrations of metals associated with the pyrite frac- tion increased considerably at depth (27.5 cm). In the low salt marsh soils (with anoxic conditions at the surface) maximum concentrations of metal sulfides were found in the surface layers of soils colonized by Spartina maritima. These results are explained by the double effect exerted by roots in strongly re- duced soils. On the one hand, they stimulate the activity of sulfate-reducing bacteria and on the other, they favour the partial oxidation of the soil, thus generating polysulfides with which Fe 2+ immediately precipitates as pyrite, whereas in the deepest, permanently anoxic layers, pyrite must be formed in a reaction in which FeS is an intermediate, as follows: FeS + H2S → FeS2 +H 2. Concentrations of metal sulfides also varied greatly with the season, with two patterns being distinguished. In soils colonized by S. maritima in both high and low salt marshes, the lowest concentrations were found in summer. At this time of the year there is a net loss of metal sulfides throughout the profile, presumably due to physi- ological activity of plants (evapotranspiration and release of oxygen from roots). In contrast, maximum concentrations of AVS and pyritic metals were found in the summer in the low salt marsh soils not colonized by vascular plants (creek bottom). In this case, the higher temperatures increased the activity of sulfur-reducing bacteria leading to synthesis and accumulation of metal sulfides in the soil.