Determination of spatial and temporal variability of pH and dissolved oxygen concentrations in a seasonally hypoxic semi-enclosed marine basin using continuous monitoring

2014 ◽  
Vol 6 (15) ◽  
pp. 5489-5497 ◽  
Author(s):  
Timothy Sullivan ◽  
Ciara Byrne ◽  
Luke Harman ◽  
John Davenport ◽  
Rob McAllen ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Temporal Variability ◽  
Continuous Monitoring ◽  
Spatial And Temporal Variability ◽  
Ph Values ◽  
Abrupt Changes ◽  
Seasonal Hypoxia ◽  
Marine Basin ◽  
Lough Hyne

Profiles of the Western Trough, Lough Hyne, show abrupt changes in measured pH values associated with stratification during seasonal hypoxia and anoxia.

scholarly journals Determination of Spatial and Temporal Variability of Soil Hydraulic Conductivity for Urban Runoff Modelling

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 941 ◽  
Author(s):  
Matej Radinja ◽  
Ines Vidmar ◽  
Nataša Atanasova ◽  
Matjaž Mikoš ◽  
Mojca Šraj
Keyword(s):  
Hydraulic Conductivity ◽  
Temporal Variability ◽  
Water Repellency ◽  
Infiltration Rate ◽  
Control Measures ◽  
Soil Conditions ◽  
Spatial And Temporal Variability ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic

Soil hydraulic conductivity has a direct influence on infiltration rate, which is of great importance for modelling and design of surface runoff and stormwater control measures. In this study, three measuring techniques for determination of soil hydraulic conductivity were compared in an urban catchment in Ljubljana, Slovenia. Double ring (DRI) and dual head infiltrometer (DHI) were applied to measure saturated hydraulic conductivity (Ks) and mini disk infiltrometer (MDI) was applied to measure unsaturated hydraulic conductivity (K), which was recalculated in Ks in order to compare the results. Results showed significant differences between investigated techniques, namely DHI showed 6.8 times higher values of Ks in comparison to DRI. On the other hand, Ks values obtained by MDI and DRI exhibited the lowest difference. MDI measurements in 12 locations of the small plot pointed to the spatial variability of K ranging between 73%–89% as well as to temporal variability within a single location of 27%–99%. Additionally, a reduction of K caused by the effect of drought-induced water repellency was observed. Moreover, results indicate that hydrological models could be enhanced using different scenarios by employing a range of K values based on soil conditions.

scholarly journals Unsegmented flow approach for on-line monitoring of pH, conductivity, dissolved oxygen and determination of nitrite and ammonia in aquaculture

1994 ◽  
Vol 16 (2) ◽  
pp. 59-62 ◽  
Author(s):  
A. C. Ariza ◽  
P. Linares ◽  
M. D. Luque de Castro ◽  
M. Valcárcel
Keyword(s):  
Dissolved Oxygen ◽  
Continuous Monitoring ◽  
Sea Water ◽  
Flow System ◽  
Photometric Determination ◽  
Fish Feed ◽  
Fish Breeding ◽  
On Line ◽  
High Concentrations

A fully automated flow system for on-line monitoring of analytes/parameters of interest in aquaculture is described. The approach has been optimized for the photometric determination of nitrite and ammonia and the continuous monitoring of pH, conductivity and dissolved oxygen, but these analytes/parameters are readily changeable as required. The system has been tested by monitoring these species in the input and output sea water streams of tanks at a fish breeding farm and also by monitoring water containing high concentrations of fish feed.

scholarly journals OCEANOGRAPHIC OBSERVATIONS IN THE LAGOON OF KAIAFA (W PELOPONNESE)

2018 ◽  
Vol 36 (2) ◽  
pp. 1026
Author(s):  
Δ. Μπούζος ◽  
Ν. Κοντόπουλος
Keyword(s):  
Dissolved Oxygen ◽  
Hot Springs ◽  
Marine Ecosystem ◽  
Sampling Period ◽  
Cold Period ◽  
Spatial And Temporal Variability ◽  
Sampling Station ◽  
Continuous Increase ◽  
Ph Values ◽  
Lagoonal Water

The Kaifa lagoon is a coastal marine ecosystem located in the Kyparisiakos Bay. The purpose of this study is to: (a) To determine the spatial and temporal changes of the physicochemical parameters in the water column of the Kaifa lagoon and (b). To create a base of information for future use for the restoration of the lagoon. Temperature, salinity, pH and dissolved oxygen were measured insitu in 28 stations. Furthermore, water samples were taken for the determination of NO2, NO3, NH4 and PO4 on seasonal bnsin from November '94 to September '95. The temperature was fluctuating from 15,90 °C in March to 30,41 °C in late August and late September. Further the seasonal variation of the temperature showed the expected two thermal periods. The first period is a hot period showing a continuous increase of temperature from March to September. The second period is a cold period showing a continuous decrease of temperature from the September to March. For each period of sampling the temperature of lagoonal water in all the extent of the lagoon remains practically constant because the fluctuation of temperature is very small each time. The salinity varied between 7,2%o and 9,20%o. The salinity like the temperature presented seasonal fluctuation patterns but the lagoon is brackish all the year round. The spatial changes of salinity were absent for every sampling period. The pH values ranged from 6,70 to 8,40. So, the pH values fluctuated in the normal levels for aquatic animals. Further, these are relatively high in spring (arithmetic mean=7.8) owing probably to higher photosynthesis rate. Dissolved oxygen ranges from 3,30 mg/l to 10,00 mg/l. In the sampling periods of September and November the oxygen values were less than 7,00mg/l for a large part of the lagoon except southern margins. This evidence suggests dangerous conditions for the fish life. Phosphate concentrations were low (0,010 mg/l - 0,07 mg/l), in November. On the contrary the phosphate levels were high (on the average 0,111 mg/l) in the sampling period of September and in particular in the southern part of the lagoon. So, this part indicated photosynthetic activity. Further, In March the phosphate concentrations have an intermediate value for every sampling station in relation to the other sampling periods. Ammonia concentrations were considered high (0,24 mg/l - 2,68 mg/l) all the year round. Nitrate levels fluctuated around normal values (0,018 mg/l -0,11mg/l) during the year. The high amount of the ammonia nitrite and nitrate in November suggests the pollution of lagoon from the fertilizers into lagoon through two drainage canals. Nitrite concentrations were high during the cold period (0,041 mg/l - 0,280 mg/l). The spatial and temporal variability of the abiotic parameters of the lagoonal water must be attributed mainly to the strong influence of fresh water witch is discharged into the lagoon from a adjacent karst with hot springs.

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