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Georgios K. Sylaios Vassilios A. Tsihrintzis 《Environmental Modeling and Assessment》2009,14(1):59-72
The nutrient dynamics of the Strymonikos and Ierissos Gulfs, two semienclosed coastal water bodies, are studied using a simple
steady-state budget model, according to the Land–Ocean Interaction in the Coastal Zone modeling guidelines. Strymon river
plume dynamics prevailed in the area of the Inner and Outer Srymonikos Gulfs, comprising two layers, while the Ierissos Gulf
was defined as a one-box system. Seasonal and mean annual model input data for river discharge, precipitation, evaporation,
and concentrations of salt, phosphorus, and nitrogen were obtained during four field campaigns. Results from the nitrogen
and phosphorus cycling revealed the importance of river discharge in the horizontal and vertical transport of these substances
within the system. Furthermore, it occurred that the major biogeochemical transformation of nitrogen and phosphorus takes
place in the immediate nearshore zone (Inner Strymonikos Gulf), while the outer system sustains its nutrient dependence on
oceanic exchanges. Therefore, under the summer low flow conditions, the river-influenced inner system acts as a net source
of nitrogen and phosphorus, while under increased Strymon River discharge, phosphorus is transferred to the biological material
(and the sediments), and the system moves to an autotrophic state. The outer system showed an opposite behavior being autotrophic
throughout the year and heterotrophic in February. The Ierissos Gulf, a system not directly influenced by significant river
discharge, experienced a seasonally independent behavior with net heterotrophic and denitrification processes prevailing.
Model scenarios demonstrated that phosphate concentration increases, even under low river flow conditions and stimulates primary
production in excess of respiration, resulting in nitrogen fixation prevalence in the Inner Strymonikos Gulf. 相似文献
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A typology of land characteristics for the Humber catchment in central/eastern England is identified in relation to land
use, hydrology and demographic, topographic and geological characteristics, using GIS and statistical analyses. Empirical
relationships between land characteristics and water quality were examined in relation to the spatial variability in water
quality across the Humber catchment. Analyses of relationships between land characteristics and water quality were undertaken
at two hierarchical scales: (1) individual catchments and (2) localities of 10 km radius draining to each sampling site. The
importance of urban and agricultural sources was identified, together with a hydrological component linked to dilution of
point source inputs and mobilisation of specific sediment-associated contaminants in higher-energy (higher-flow) environments.
High-solubility (dissolved) chemical determinands (such as B, Cl and SO4), which undergo conservative transport through the river network, show the strongest linkages with land characteristics at
the catchment scale. Cr, Zn and Ca show stronger correlations with land characteristics at the locality rather than the catchment
scale, indicating that the concentrations of these determinands are more closely linked to the availability of localised sources.
This work provides a starting point for investigating how changes in land use and management of drainage basins might impact
river water quality at the regional scale and fluxes to the coastal zone, by providing a mechanism for examining linkages
between regional-scale land characteristics and river water quality. The next step requires development of the approach within
a more rigorous statistical framework and the extension of the regional analysis within a wider national and international
context.
Electronic Publication 相似文献
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九龙江河口生物地球化学元素通量的初步模拟 总被引:5,自引:0,他引:5
按照LOICZ的模拟指南 ,九龙江河口区采用单箱模型模拟其生物地球化学元素的通量。结果表明 ,九龙江河流输入进河口系统的DIP通量为 2 .81× 10 7mol/a ,交换流带入河口区DIP通量为 10 .93× 10 7mol/a ,因此 ,净沉淀量为 8.0 5× 10 7mol/a。九龙江河流输送进河口系统的DIN通量为 73.47× 10 8mol/a ,它远高于DIP的通量。因此 ,此河口区系统内部有 7.6 6× 10 8mol/a的差额才能达到平衡。 相似文献
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