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81.
Transport and accumulation of sediment and contaminants in the Lagoon of Kuršiųmarios (Lithuania) and Baltic Sea 总被引:2,自引:0,他引:2
Olegas Pustelnikovas 《Aquatic Ecology》1994,28(3-4):405-411
In this paper an overview is given of earlier work on transport, deposition AND transformation of suspended matter, and contaminants
(metals, hydrocarbons) in Lithuanian coastal waters as well as in other parts of the Baltic Sea. The Lithuanian river Nemunas
dischargesc. 600.106 kg suspended matter into the Kuršių Marios Lagoon annually, of which two thirds are accumulated in the lagoon. The remainder
is exported to the Baltic Sea through the Klaipéda Strait influencing biological activity in the coastal zone. Sedimentation
rate in Kuršių Marios Lagoon is estimated at 3.2 mm y−1. In the last 50 years the surface area of the lagoon decreased by 0.7 km2 y−1. Concentration profiles of metals and hydrocarbons were measured in the Kuršių Marios Lagoon, the Baltic proper, and in the
Gulf of Finland. Among hydrocarbons both anthropogenic and compounds from natural sources are present. It is argued that correct
interpretation of concentration horizons in sediment may be hampered by various processes,e. g. early sedimentogenesis and diagenesis, and cyclic salinity changes in the Baltic Sea. 相似文献
82.
Göran Dave Benneth Dennegård 《Journal of Aquatic Ecosystem Stress and Recovery (Formerly Journal of Aquatic Ecosystem Health)》1994,3(3):207-219
Superficial (0 to 2 cm) sediments were sampled from 62 sites in Kattegat and Skagerrak during autumn 1989 and spring 1990, tested for toxicity to Daphnia magna and Nitocra spinipes (Crustacea) and analyzed for heavy metals (Cd, Cr, Cu, Hg, N, Pb, Zn), nutrients (N and P) and organic carbon. Whole sediment toxicity to Nitocra spinipes, expressed as 96-h LC50, ranged from 1.8 to > > 32 percent sediment (wet wt), which is equivalent to 0.63 to 53 percent dry wt. Sediment total metal concentrations (mg kg-1 dry wt) ranged from 0.01 to 0.32 for Cd, 8 to 57 for Cr, 3 to 40 for Cu, 0.03 to 0.86 for Hg, 3 to 43 for Ni, 6 to 37 for Pb and 21 to 156 for Zn. Analyzed concentrations of heavy metals were tested for correlation with whole sediment toxicity normalized to dry wt, and significant correlations (Spearman p<0.05) were found for Cd, Cr, Cu, Hg, and Ni. However, the analyzed concentrations of these metals were below the spiked sediment toxicity of these heavy metals to N. spinipes, except for Cr and Zn for which analyzed maximum concentrations approached the 96-h spiked sediment LC50s. There was no improvement in correlation between the sum of heavy metal concentrations normalized to their spiked toxic concentrations (Toxic Unit approach) and the whole sediment toxicity. Calculated heavy-metal-derived toxicity based on toxic units and whole sediment toxicity ranged from 0.1 to 24 (mean value 2.3 and SD 4.2). Theoretically, a value of 1.0 would explain whole sediment toxicity from measured metal concentrations using this approach. Thus, in spite of the fact that the total concentrations of the heavy metals were sufficient to cause toxicity based on an additive model for most of these sediments, the observed toxicity of the sediments from Kattegat and Skagerrak could not exclusively be explained by the concentrations of heavy metals, except for Cr and Zn at their maximum concentrations. Therefore, other pollutants than these heavy metals must also be considered as possible sediment toxicants. 相似文献
83.
84.
呼和浩特地区蔬菜污染现状综合评价 总被引:1,自引:0,他引:1
呼和浩特地区蔬菜污染现状综合评价杨在中(内蒙古大学,呼和浩特010021)黄雅琴(内蒙古环境监测中心站,呼和浩特010010)ComprehensiveassessmentonpollutionstatusofvegetablesinHuhehot.... 相似文献
85.
Total body burdens of Zn, Pb, Al and Cu were measured in Swedish marine nemerteans sampled from an area close to a major source
of pollution. Accumulation patterns varied both seasonally and spatially. The results suggest that nemerteans may be useful
bioindicator species in environmental monitoring programmes. 相似文献
86.
食蚜绒螨对棉花苗蚜的控制作用研究 总被引:1,自引:0,他引:1
通过2年的田间调查和小区试验发现:(1)食蚜绒螨与被寄生的棉蚜有翅蚜和无翅蚜在时间—数量分布上具相似性。(2)棉蚜带螨率结果说明,50%有翅蚜可被迁入初期杀死,可使大部分棉蚜繁殖力下降或不能生殖;(3)棉田播种前施肥、浅翻,对食蚜绒螨的发生量不具明显影响;(4)食蚜螨在棉田期其他棉蚜天敌缺少的情况下,填补了此期控蚜天敌时间生态位的空缺,成为棉田生态系统中不可缺少的一员。 相似文献
87.
Eduardo Moreno-Jiménez Fernando T. Maestre Maren Flagmeier Emilio Guirado Miguel Berdugo Felipe Bastida Marina Dacal Paloma Díaz-Martínez Raúl Ochoa-Hueso César Plaza Matthias C. Rillig Thomas W. Crowther Manuel Delgado-Baquerizo 《Global Change Biology》2023,29(2):522-532
Soil micronutrients are capital for the delivery of ecosystem functioning and food provision worldwide. Yet, despite their importance, the global biogeography and ecological drivers of soil micronutrients remain virtually unknown, limiting our capacity to anticipate abrupt unexpected changes in soil micronutrients in the face of climate change. Here, we analyzed >1300 topsoil samples to examine the global distribution of six metallic micronutrients (Cu, Fe, Mn, Zn, Co and Ni) across all continents, climates and vegetation types. We found that warmer arid and tropical ecosystems, present in the least developed countries, sustain the lowest contents of multiple soil micronutrients. We further provide evidence that temperature increases may potentially result in abrupt and simultaneous reductions in the content of multiple soil micronutrients when a temperature threshold of 12–14°C is crossed, which may be occurring on 3% of the planet over the next century. Altogether, our findings provide fundamental understanding of the global distribution of soil micronutrients, with direct implications for the maintenance of ecosystem functioning, rangeland management and food production in the warmest and poorest regions of the planet. 相似文献
88.
David W. Ow 《In vitro cellular & developmental biology. Plant》1993,29(4):213-219
Summary Plants and certain fungi respond to heavy metal toxicity with the induced synthesis of metal-binding peptides known as phytochelatins
(PCs). With cadmium, PCs can bind the metal to form a low molecular weight PC-Cd complex and a high molecular weight PC-Cd-S2− complex. The sulfide ions enhance the stability and Cd-binding capacity of the metal chelate, and formation of this sulfide-containing
complex is associated with enhanced tolerance to cadmium. Molecular analyses of two fission yeast mutants that fail to produce
a wild type level of the PC-Cd-S2− complex have determined that a vacuolar membrane transporter and several enzymes of the purine biosynthesis pathway are necessary
in vivo for formation of the PC- Cd-S2− complex. A model based on vacuolar sequestration of the PC-Cd complex by an ATP-binding cassette-type transporter and its
subsequent maturation into the stable PC-Cd-S2− complex via the actions of two purine biosynthetic enzymes is described.
Presented in the Session-in-Depth Bioremediation through Biotechnological Means at the 1993 Congress on Cell and Tissue Culture,
San Diego, CA, June 5–9, 1993. 相似文献
89.
Sigrun Machemer-Röhnisch Richard Bräucker Hans Machemer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1993,171(6):779-790
Summary In the statocystoid-bearing, flat ciliate Loxodes, the peculiar steady locomotion on submersed substrates (called gliding) was investigated between 1 g and 5.4 g under controlled environmental conditions in a centrifuge microscope. Videorecordings of the movements of large cell populations were processed with an automated analysis procedure. At 1 g, possible sedimentation was fully compensated, and vertical shifts of the population were neutralized because upward and downward orientations of the cells occurred at equal proportions (neutral gravitaxis). With rising gravity the resultant velocity of upward-gliding cells remained unchanged, whereas the velocity of downward-gliding cells increased continuously. Long-term exposure to hypergravity did not generate detectable signs of adaptation. The bipolar orientation of Loxodes persisted even under fivefold normal gravity, but the axis of orientation rotated from the gravity axis in the counterclockwise direction. The data suggest that both gravikinesis and graviorientation of gliding Loxodes are instrumental in perfect neutralization of sedimentation at terrestrial conditions. 相似文献
90.
Max R. Brown Hannes Becher Sebastian Williams Alex D. Twyford 《American journal of botany》2023,110(1):e16100