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It has been observed in Venice Lagoon that salt-marshes have appeared and developed as a consequence of the presence of artificial or biological confinements, maintaining separation domains in the hydrodynamic wave and tidal flow field. 相似文献
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Bellucci LG Frignani M Cochran JK Albertazzi S Zaggia L Cecconi G Hopkins H 《Journal of environmental radioactivity》2007,97(2-3):85-102
Five salt marsh sediment cores from different parts of the Venice Lagoon were studied to determine their depositional history and its relationship with the environmental changes occurred during the past approximately 100 years. X-radiographs of the cores show no disturbance related to particle mixing. Accretion rates were calculated using a constant flux model applied to excess (210)Pb distributions in the cores. The record of (137)Cs fluxes to the sites, determined from (137)Cs profiles and the (210)Pb chronologies, shows inputs from the global fallout of (137)Cs in the late 1950s to early 1960s and the Chernobyl accident in 1986. Average accretion rates in the cores are comparable to the long-term average rate of mean sea level rise in the Venice Lagoon ( approximately 0.25 cm y(-1)) except for a core collected in a marsh presumably affected by inputs from the Dese River. Short-term variations in accretion rate are correlated with the cumulative frequency of flooding, as determined by records of Acqua Alta, in four of the five cores, suggesting that variations in the phenomena causing flooding (such as wind patterns, storm frequency and NAO) are short-term driving forces for variations in marsh accretion rate. 相似文献
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Cecconi Elva Fortuna Lorenzo Peplis Marco Tretiach Mauro 《Environmental science and pollution research international》2021,28(13):16214-16226
Environmental Science and Pollution Research - In bioaccumulation studies, sample devitalization through acid washing or oven drying is commonly applied to enhance the element accumulation... 相似文献
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Over the past century, the Venice lagoon has experienced a high rate of wetland loss and a strong net export of sediments;
currently the local Authority is running several projects for beneficial use of dredging materials. From March 1993 until
March 1995 the accretionary response of wetlands in the lagoon to changing water levels was studied. Vertical accretion, short
term sedimentation and surface elevation change were measured at six sites with varying sediment availability and wave energy.
Short term sedimentation averaged 6.85 g m−2 d−1 with a minimum of 0.06 g and a maximum of 72 g during periods of high tides and storms. Over two years accretion ranged from
0.3 to 2.3 cm/yr and surface elevation change ranged from+0.7 to −3.7 cm/yr. The sites with highest accretion were near a
river mouth and a site with strong wave energy and rapid erosion of the marsh edge with a high resuspended sediment availability.
The rate of accretion at three sites was clearly sufficient to offset relative sea level rise, but a saline site with low
sediment availability had the lowest accretion. A sediment fence significantly increased accretion at one site. The results
suggest that reduction of turbulent motion or increasing sediment availability are needed to offset wetland loss in different
areas of the lagoon. 相似文献
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