The local responses of aquatic ecosystems to adjacent grassland conservation: Can streams of dreams exist in a degraded riverscape?

2021 ◽  
Author(s):  
David A. Schumann ◽  
Katie N. B. Graeb ◽  
Jarrett Pfrimmer ◽  
Joshua D. Stafford ◽  
Steven R. Chipps
Keyword(s):  
Aquatic Ecosystems ◽  
Local Responses ◽  
Grassland Conservation

Extracellular enzymatic activities in the aquatic ecosystems of the Danube Delta. 2. Alkaline phosphatase activity

2021 ◽  
Vol 26 (1) ◽  
pp. 2269-2274
Author(s):  
IOAN PĂCEŞILĂ ◽  
EMILIA RADU
Keyword(s):  
Alkaline Phosphatase ◽  
Water Column ◽  
Aquatic Ecosystems ◽  
Temporal Dynamics ◽  
Extracellular Enzyme ◽  
Danube Delta ◽  
Phytoplankton Communities ◽  
Extracellular Enzymatic Activities ◽  
Adjacent Channels ◽  
Hydrolysis Of

Phosphorus is one of the most important inorganic nutrients in aquatic ecosystems, the development and functioning of the phytoplankton communities being often correlated with the degree of availability in assimilable forms of this element. Alkaline phosphatase (AP) is an extracellular enzyme with nonspecific activity that catalyses the hydrolysis of a large variety of organic phosphate esters and release orthophosphates. During 2011-2013, AP Activity (APA) was assessed in the water column and sediments of several aquatic ecosystems from Danube Delta: Roșu Lake, Mândra Lake and their adjacent channels – Roșu-Împuțita and Roșu-Puiu. The intensity of APA widely fluctuated, ranging between 230-2578 nmol p-nitrophenol L-1h-1 in the water column and 2104-15631 nmol p-nitrophenol g-1h-1 in sediment. Along the entire period of the study, APA was the most intense in Roșu-Împuțita channel, for both water and sediment samples. Temporal dynamics revealed its highest values in summer for the water column and in autumn for sediment. Statistical analysis showed significant seasonal diferences of the APA dynamics in spring vs. summer and autumn for the water column, and any relevant diferences for sediment.

A Process of Glocalisation? Roman Marble Imports and the Rise of Blocked-Out Capitals in Local Stone

2020 ◽  
pp. 33-45
Author(s):  
Matthias Grawehr
Keyword(s):  
Roman Empire ◽  
Eastern Mediterranean ◽  
High Quality ◽  
White Marble ◽  
Aesthetic Preference ◽  
Local Responses ◽  
Global Trend ◽  
Short Period ◽  
New Type ◽  
Local Materials

In the Augustan Age, a new aesthetic preference was propagated in the Roman Empire – the surface of white marble was valued as it symbolised the strength and superiority of the ‘new age’. Soon, an immense trade in high quality marble over land and sea developed to meet the emergent demand. While the development and scale of this trade is well studied, the repercussions that the new aesthetic preference had on the local architectural traditions in areas where no marble was close at hand is not commonly considered. In this contribution, two developments are traced, taking the Corinthian capital as the leitmotif. First, in the short period between c. 40 and 10 BC, patrons would choose imitation of marble in plaster to meet up with the demands of the new standard and to demonstrate their adherence to the Empire. In the second line of development, a different path was taken – a conscious use of local materials which went hand in hand with the development of a new type of capital, the so-called ‘Nabataean blocked-out’ capital. This combination turned into a new vernacular tradition across large parts of the eastern Mediterranean. Both developments were local responses to a new ‘global’ trend and can therefore be viewed as a phenomenon of glocalisation in the Roman Period.

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

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