The Control of a Small Dam in Nutrient Inputs to a Hypertrophic Estuary in a Mediterranean Climate

Avilés, Antonio; Niell, F. Xavier

doi:10.1007/s11270-006-9253-4

Cited by 28 publications

(15 citation statements)

References 35 publications

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“…Nitrogenous DOM is expected to follow complex dynamics. In situ processes such as phytoplankton uptake, mineralization and nitrification has been observed in other Mediterranean catchments (Lolite-Herera et al, 2009;Aviles & Niell, 2007), whereas DON ammonification by bacteria and subsequent nitrification of the released ammonium in freshwater systems have been discussed in a number of previous studies using incubation experiments (Selmer, 1998;Kerner & Spitzy, 2001;Badr et al, 2008). The exact mechanisms responsible for the observed distribution of DON in our study system cannot be identified from these data alone and additional process-focused experiments are needed to further resolve relative contributions of different processes in this system.…”

Section: In Situ Processesmentioning

confidence: 84%

Dissolved organic matter cycling in eastern Mediterranean rivers experiencing multiple pressures. The case of the trans-boundary Evros River

et al. 2014

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Despite their high ecological value, transboundary Mediterranean rivers and their coastal wetlands are subject to increasing anthropogenic stressors (intensive agriculture, industrial activities, population density) and are predicted to be particularly vulnerable to future climate change. Improving understanding of elemental cycling in these systems is critical for understanding these ecosystems' functioning and response to future pressures. Here we studied dissolved organic matter (C, N and P) cycling in the Evros/Марица/Meriç River, one of the most heavily polluted and, simultaneously, most ecologically valuable transboundary river systems in the Eastern Mediterranean. Measurements were performed in different seasons over a year (April 2009, July 2009, September 2009, April 2010 and July 2010 and along transects extending more than 70 km from the freshwater end-member to 2-km offshore in the Aegean Sea. Dissolved organic carbon (DOC) in Evros waters (DOC: 119 -496 μmol/L) was comparable to that of other large Mediterranean rivers (Rhone, Po). The organic component of N and P showed increased variability and ranged from 0.65 to 56 μmol/L for DON and from 0.03 to 4.15 μmol/L for DOP. In the lower parts of the river, where all point and nonpoint inputs converge, the high inorganic N inputs favored elevated assimilation rates by phytoplankton, and resulted in increased chl-a concentrations (up to 488μg/L) and autochthonous dissolved organic matter (DOM) production under dry conditions and low flushing rates. Moreover, the distribution of carbohydrates revealed a constant background of soil-derived mono-saccharides, and additional contributions of poly-saccharides during phytoplankton bloom events. During the dry season, inorganic nutrients and DOM from upstream sources remained restricted in the lower parts of the river (delta and coastal wetlands), while during high flow conditions upstream DOM was flushed to the sea and organic nitrogen forms became an important component of TDN (at least 40%) in the coastal and shelf waters. The co-existence of terrigenous material with autochthonous production and some anthropogenic contributions is supported by the large variability found in DOC:DON (4 -96) and DOC:DOP (79 ->1000) ratios, the positive correlation of DOC vs chl-a (r 2 = 0.76, p=0.01 for July 2009; r 2 =0.77 p=0.01 for September 2009), the decoupling between DOC and DON, and the observed spatial distribution of inorganic N forms including ammonium. Our results illustrate the combined and complex influences of (i) seasonally dependent hydrological processes, (ii) consistent upstream anthropogenic pollution sources, and (iii) irregular water resource management practices on C, N, P dynamics along this heavily polluted transboundary river system, its delta and wetland ecosystem, and adjacent Mediterranean coastal waters.

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Section: In Situ Processesmentioning

confidence: 84%

Dissolved organic matter cycling in eastern Mediterranean rivers experiencing multiple pressures. The case of the trans-boundary Evros River

et al. 2014

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“…The main sources of the dissolved silica present in surface waters are soil leaching and erosion, the impacts of agriculture and management being less marked than in the cases of nitrogen and phosphorus (Billen et al 1991;Anderson and Downing 2006;Avilés and Niell 2007). The DSi in aquatic ecosystems is taken up by siliceous phytoplankton, i.e.…”

Section: Introductionmentioning

confidence: 99%

Dissolved Silica Retention and Its Impact on Eutrophication in a Complex of Mountain Reservoirs

Koszelnik

Tomaszek

2007

Water Air Soil Pollut

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This paper reports on studies conducted during 2005 in the ecosystem of the SolinaMyczkowce mountain complex of mesotrophic reservoirs on the San River, SE Poland. Of the 1,950 t of dissolved silica calculated to flow into the reservoirs in the course of the year, c. 20% of the load was retained in the reservoirs. However, most of this retention took place in the lower Myczkowce Reservoir. Far-reaching depletion to below 10 μM L −1 of silicate was noted during the summer in the epilimnetic waters of the two reservoirs. In turn, the hypolimnion was seen to go through an enrichment process connected with sedimentation and releases from sediment. The observed depletion causes a decrease in the DSi:DIP ratio in the euphotic zone of the reservoirs, with simultaneous growth of nonsiliceous algae expressed as chl a concentration.

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“…Accordingly, the lower concentrations of DSi observed in the overlying water from Lake Daihai were attributed to the uptake and assimilation of diatom phytoplankton. Generally, the concentration levels and spatial distribution of DSi in overlying water are mainly regulated by soil leaching and erosion and rock weathering of the lake basin, rather than anthropogenic inputs (Anderson and Downing 2006;Avilés and Niell 2007). Thus, the high-concentration areas of DSi found in the northwestern and southern areas of Lake Daihai responded the influence of the main lake inlets (such as Yuanzi, Jiucai, Buliang, and Tiancheng Rivers) on DSi spatial distribution (Fig.…”

Section: Dsimentioning

confidence: 99%

Environmental geochemistry of dissolved and biogenic silicon and its nutrient limitation effects in an inland lake, China

Lü

Wang

et al. 2015

Environ Sci Pollut Res

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Silicon (Si) processing and retention play a key role in nutrients biogeochemistry cycling in aquatic environment. In order to interpret the possibility of Si limitation, multivariate analysis was performed based on stoichiometric nutrients balance, distribution characteristics of dissolved silicon (DSi) and biogenic silica (BSi), adsorption behavior, and response relation of BSi with paleoenvironment in water-sediment system of Lake Daihai. The spatial distributions of DSi and BSi in the water-sediment system indicated that terrigenous inputs (such as the weathering of rock and soil in the drainage basin) was the main sources of Si. Meanwhile, grain sizes of sediments, water hydrogeochemistry, and space competition between diatoms and submergent or emerging plants also played important roles in regulating BSi spatial distributions. The sediments from the lake presented obvious releasing trend of Si at low initial concentrations (≤ 3 mg/L) in adsorption experiments, indicating that the sediments were the source of Si to the overlying water. Furthermore, the good response relation between BSi and paleoenvironment observed in the sediment profiles from Lake Daihai indicated that the main reasons for Si limitation to siliceous plankton were different during different periods. The multi-evidences of distribution characteristics, stoichiometric nutrient balance, adsorption behaviors, and response to paleoenvironment were jointly indicative of Si limitation on the primary production of siliceous plankton in Lake Daihai.

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The Control of a Small Dam in Nutrient Inputs to a Hypertrophic Estuary in a Mediterranean Climate

Cited by 28 publications

References 35 publications

Dissolved organic matter cycling in eastern Mediterranean rivers experiencing multiple pressures. The case of the trans-boundary Evros River

Dissolved organic matter cycling in eastern Mediterranean rivers experiencing multiple pressures. The case of the trans-boundary Evros River

Dissolved Silica Retention and Its Impact on Eutrophication in a Complex of Mountain Reservoirs

Environmental geochemistry of dissolved and biogenic silicon and its nutrient limitation effects in an inland lake, China

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