scholarly journals Dissolved oxygen and water temperature dynamics in lowland rivers over various timescales

2015 ◽  
Vol 63 (4) ◽  
pp. 353-363 ◽  
Author(s):  
Agnieszka Rajwa-Kuligiewicz ◽  
Robert J. Bialik ◽  
Paweł M. Rowiński
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variability ◽  
Physical Factors ◽  
Lowland Rivers ◽  
Physical Conditions ◽  
The Impact ◽  
Floodplain Hydrology ◽  
Oxygen Dynamics

Abstract The impact of floodplain hydrology on the in-stream dissolved oxygen dynamics and the relation between dissolved oxygen and water temperature are investigated. This has been done by examining the time series of dissolved oxygen and water temperature coupled with meteorological and hydrological data obtained from two lowland rivers having contrasting hydrological settings. Spectral analysis of long-term oxygen variations in a vegetated river revealed a distinct scaling regime with slope ‘–1’ indicating a self-similar behaviour. Identical slopes were obtained for water temperature and water level. The same power-law behaviour was observed for an unvegetated river at small timescales revealing the underlying scaling behaviour of dissolved oxygen regime for different types of rivers and over various time scales. The results have shown that the oxygenation of a vegetated river is strongly related to its thermal regime and flow conditions. Moreover, analysis of short-term fluctuations in the unvegetated river demonstrated that physical factors such as rainfall and backwaters play a substantial role in the functioning of this ecosystem. Finally, the results show that the relation between water temperature and dissolved oxygen concentration at the diurnal timescale exhibits a looping behaviour on the variable plot. The findings of this study provide an insight into the sensitivity of rivers to changing hydro-physical conditions and can be useful in the assessment of environmental variability.

scholarly journals Extreme Meteorological Events in a Coastal Lagoon Ecosystem: The Ria de Aveiro Lagoon (Portugal) Case Study

2021 ◽  
Vol 9 (7) ◽  
pp. 727
Author(s):  
José Fortes Lopes ◽  
Carina Lurdes Lopes ◽  
João Miguel Dias
Keyword(s):  
Water Temperature ◽  
Coastal Lagoon ◽  
Early Summer ◽  
Extreme Weather Events ◽  
Climate Change Scenarios ◽  
State Variables ◽  
Ria De Aveiro ◽  
Physical Conditions ◽  
Weather Events ◽  
The Impact

Extreme weather events (EWEs) represent meteorological hazards for coastal lagoon hydrodynamics, of which intensity and frequency are increasing over the last decades as a consequence of climate changes. The imbalances they generated should affect primarily vulnerable low-lying areas while potentially disturbing the physical balances (salt and water temperature) and, therefore, the ecosystem equilibrium. This study arises from the need to assess the impact of EWEs on the Ria de Aveiro, a lagoon situated in the Portuguese coastal area. Furthermore, it was considered that those events occur under the frame of a future sea-level rise, as predicted by several climate change scenarios. Two EWEs scenarios, a dry and an extremely wet early summer reflecting past situations and likely to occur in the future, were considered to assess the departure from the system baseline functioning. It was used as a biogeochemistry model that simulates the hydrodynamics, as well as the baseline physical and biogeochemistry state variables. The dry summer scenario, corresponding to a significant reduction in the river’s inflow, evidences a shift of the system to a situation under oceanic dominance characterized by colder and saltier water (~18 °C; 34 PSU) than the baseline while lowering the concentration of the nutrients and reducing the phytoplankton population to a low-level limit. Under a wet summer scenario, the lagoon shifted to a brackish and warmer situation (~21 °C, <15 PSU) in a time scale of some tidal periods, driven by the combining effect of the tidal transport and the river’s inflow. Phytoplankton patterns respond to variability on local and short-term scales that reflect physical conditions within the lagoon, inducing nutrient-supported growth. Overall, the results indicate that EWEs generate local and transient changes in physical conditions (namely salinity and water temperature) in response to the characteristic variability of the lagoon’s hydrodynamics associated with a tidal-dominated system. Therefore, in addition to the potential impact of changing physical conditions on the ecosystem, saline intrusion along the lagoon or the transfer of brackish water to the mouth of the system are the main consequences of EWEs, while the main biogeochemistry changes tend to remain moderate.

Impact of hypolimnetic oxygenation on profundal macroinvertebrates in a eutrophic lake in central Alberta. I. Changes in macroinvertebrate abundance and diversity

1997 ◽  
Vol 54 (9) ◽  
pp. 2157-2169 ◽  
Author(s):  
W P Dinsmore ◽  
E E Prepas
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Eutrophic Lake ◽  
Water Bodies ◽  
Macroinvertebrate Communities ◽  
South Basin ◽  
The North ◽  
Hypolimnetic Oxygenation ◽  
Abundance And Diversity ◽  
The Impact

Hypolimnetic oxygenation from 1988 to 1991 in the north basin of Amisk Lake increased mean summer (June-August) dissolved oxygen (DO) concentrations in the deep hypolimnion (25 m) from <0.4 mg ·L-1 during pretreatment years (1980-1987) to 2.7 mg ·L-1 during treatment. Mean summer hypolimnetic temperatures at 25 m also increased from 6.3 (pretreatment) to 8.1°C (treatment). Profundal (15-25 m) Chironomus spp. abundance in the treated basin increased from <100 to >2000 ·m-2 from 1988 to 1991 whereas Chaoborus spp., Tubificidae, and other taxa remained uncommon at similar depths. Shannon-Weaver indices of diversity decreased as oxygenation progressed, in contrast with previous studies. Similar patterns in densities and diversity were observed in the south basin of Amisk Lake, although the increase in DO concentrations was smaller relative to the north basin. The impact of increased water temperature on macroinvertebrates appeared minor relative to the effects of increased DO concentrations. No changes in macroinvertebrate communities were noted in a nearby reference lake during the study period. Responses to hypolimnetic oxygenation in Amisk Lake differed markedly from those reported for smaller, single-basined water bodies.

scholarly journals Monthly Variation of Physico-Chemical Parameters of Haleji lake, Sindh, Pakistan

2019 ◽  
Vol 10 (1) ◽  
pp. 36-41
Author(s):  
Shahina Rao ◽  
Muhammad Arshad Azmi
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Air Temperature ◽  
Physical Factors ◽  
Monthly Variation ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Light Green

Present work is based on the physico-chemical parameters of Haleji lake. Physical factors and chemistry oflake water were analyzed with regular intervals. The color of water showed variation from light green to yellowishgreen, air temperature ranged between 20 °C to 35 °C, water temperature between 17 °C to 33 °C , pH 5.5 to 7.5,dissolved oxygen 2.04 mg/L to 6.44 mg/L, salinity 0.32 mg/L to 1.1 mg/L, alkalinity from 30 mg/L to 100 mg/L,acidity 10 to 96 mg/L, sulphate 4.5 mg/L to 305 mg/L, phosphate from 1 mg/L to 190 mg/L, and nitrates 9 mg/L to 270mg/L during 2006, 2007 and 2008 respectively.

scholarly journals Maintaining Plasmodium falciparum gametocyte infectivity during blood collection and transport for mosquito feeding assays in the field

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Harouna M. Soumare ◽  
Wamdaogo Moussa Guelbeogo ◽  
Marga van de Vegte-Bolmer ◽  
Geert-Jan van Gemert ◽  
Zongo Soumanaba ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Burkina Faso ◽  
Water Temperature ◽  
The Gambia ◽  
Short Term ◽  
Infected Blood ◽  
Membrane Feeding ◽  
Thermos Flask ◽  
The Impact

Abstract Background Mosquito feeding assays using venous blood are commonly used for evaluating the transmission potential of malaria infected individuals. To improve the accuracy of these assays, care must be taken to prevent premature activation or inactivation of gametocytes before they are fed to mosquitoes. This can be challenging in the field where infected individuals and insectary facilities are sometimes very far apart. In this study, a simple, reliable, field applicable method is presented for storage and transport of gametocyte infected blood using a thermos flask. Methods The optimal storage conditions for maintaining the transmissibility of gametocytes were determined initially using cultured Plasmodium falciparum gametocytes in standard membrane feeding assays (SMFAs). The impact of both the internal thermos water temperature (35.5 to 37.8 °C), and the external environmental temperature (room temperature to 42 °C) during long-term (4 h) storage, and the impact of short-term (15 min) temperature changes (room temp to 40 °C) during membrane feeding assays was assessed. The optimal conditions were then evaluated in direct membrane feeding assays (DMFAs) in Burkina Faso and The Gambia where blood from naturally-infected gametocyte carriers was offered to mosquitoes immediately and after storage in thermos flasks. Results Using cultured gametocytes in SMFAs it was determined that an internal thermos water temperature of 35.5 °C and storage of the thermos flask between RT (~ 21.3 °C) and 32 °C was optimal for maintaining transmissibility of gametocytes for 4 h. Short-term storage of the gametocyte infected blood for 15 min at temperatures up to 40 °C (range: RT, 30 °C, 38 °C and 40 °C) did not negatively affect gametocyte infectivity. Using samples from natural gametocyte carriers (47 from Burkina Faso and 16 from The Gambia), the prevalence of infected mosquitoes and the intensity of oocyst infection was maintained when gametocyte infected blood was stored in a thermos flask in water at 35.5 °C for up to 4 h. Conclusions This study determines the optimal long-term (4 h) storage temperature for gametocyte infected blood and the external environment temperature range within which gametocyte infectivity is unaffected. This will improve the accuracy, reproducibility, and utility of DMFAs in the field, and permit reliable comparative assessments of malaria transmission epidemiology in different settings.

scholarly journals Monthly Variation of Physico-Chemical Parameters of Haleji lake, Sindh, Pakistan

2019 ◽  
Vol 10 (1) ◽  
pp. 36-41
Author(s):  
Shahina Rao ◽  
Muhammad Arshad Azmi
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Air Temperature ◽  
Physical Factors ◽  
Monthly Variation ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Light Green

Present work is based on the physico-chemical parameters of Haleji lake. Physical factors and chemistry oflake water were analyzed with regular intervals. The color of water showed variation from light green to yellowishgreen, air temperature ranged between 20 °C to 35 °C, water temperature between 17 °C to 33 °C , pH 5.5 to 7.5,dissolved oxygen 2.04 mg/L to 6.44 mg/L, salinity 0.32 mg/L to 1.1 mg/L, alkalinity from 30 mg/L to 100 mg/L,acidity 10 to 96 mg/L, sulphate 4.5 mg/L to 305 mg/L, phosphate from 1 mg/L to 190 mg/L, and nitrates 9 mg/L to 270mg/L during 2006, 2007 and 2008 respectively.

scholarly journals Kepuasan Kerja Dan Dampaknya Terhadap Profesionalisme Guru

2016 ◽  
Vol 4 (1) ◽  
pp. 143
Author(s):  
Fiska Ilyasir
Keyword(s):  
Job Satisfaction ◽  
Social Interaction ◽  
Social Factor ◽  
School Facilities ◽  
Psychological Factor ◽  
Physical Factors ◽  
Professional Educators ◽  
Physical Conditions ◽  
Financial Factors ◽  
The Impact

<p><em>This article attempts to discuss the impact of job satisfaction of teachers in Indonesia to their performance as professional educators. There are several factors that affect their satisfaction of the teacher. Psychological factor, which is related to mental and attitudes, including interest, talent, and skills; Social factor, that related to their social interaction with superiors, colleagues, students, and community. Physical factors, the factor related to the condition of the school such as policies that applied, type of work, working time, school facilities, teaching equipment facilities, teacher's office</em><em>. teacher</em><em> physical conditions </em><em>like </em><em>health, age, and so on. Financial factors </em><em>that </em><em>associated with security and welfare</em><em>, including</em><em> </em><em>sallary,</em><em> social security, </em><em>work </em><em>promotion, and so on. All </em><em>of </em><em>these factors certainly can not be changed only by the teacher, but they also need help from external parties, both government and society.</em><em></em></p><p><em> </em></p><p class="Default"><strong><em>Keyword</em></strong><em>: P</em><em>rofessional Educators</em><em></em></p>

scholarly journals Maintaining Plasmodium Falciparum Gametocyte Infectivity During Blood Collection and Transport for Mosquito Feeding Assays in the Field

2021 ◽  
Author(s):  
Harouna M. Soumare ◽  
Wamdaogo Moussa Guelbeogo ◽  
Marga van-de Vegte-Bolmer ◽  
Geert-Jan van Gemert ◽  
Zongo Soumanaba Soumanaba ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Burkina Faso ◽  
Water Temperature ◽  
The Gambia ◽  
Short Term ◽  
Infected Blood ◽  
Membrane Feeding ◽  
Thermos Flask ◽  
The Impact

Abstract BackgroundMosquito feeding assays using venous blood are commonly used for evaluating the transmission potential of malaria infected individuals. To improve the accuracy of these assays, care must be taken to prevent premature activation or inactivation of gametocytes before they are fed to mosquitoes. This can be challenging in the field where infected individuals and insectary facilities are sometimes very far apart. In this study, a simple, reliable, field applicable method is presented for storage and transport of gametocyte infected blood using a thermos flask. MethodsThe optimal storage conditions for maintaining the transmissibility of gametocytes were determined initially using cultured Plasmodium falciparum gametocytes in standard membrane feeding assays (SMFAs). The impact of both the internal thermos water temperature (35.5 – 37.8°C), and the external environmental temperature (room temp – 42°C) during long-term (4hr) storage, and the impact of short-term temperature changes (room temp – 40°C) during membrane feeding assays was assessed. The optimal conditions were then evaluated in direct membrane feeding assays (DMFAs) in Burkina Faso and The Gambia where blood from naturally infected gametocyte carriers was offered to mosquitoes immediately and after storage in thermos flasks. ResultsUsing cultured gametocytes in SMFAs it was determined that an internal thermos water temperature of 35.5°C and storage of the thermos flask between RT (~21.3°C) and 32°C was optimal for maintaining transmissibility of gametocytes for 4 hours. Short-term storage of the gametocyte infected blood at temperatures up to 38°C (range: RT, 30°C and 38°C) did not have a negative effect on gametocyte infectivity. Using samples from natural gametocyte carriers (47 from Burkina Faso and 16 from The Gambia), the prevalence of infected mosquitoes and the intensity of oocyst infection was maintained when gametocyte infected blood was stored in a thermos flask in water at 35.5°C for up to 4 hours.ConclusionsThis study determines the optimal long-term (4 hours) storage temperature for gametocyte infected blood and the external environment temperature range within which gametocyte infectivity is unaffected. This will improve the accuracy, reproducibility, and utility of DMFAs in the field, and permit reliable comparative assessments of malaria transmission epidemiology in different settings.

scholarly journals Multidecadal dynamics of the Arctic copepod Limnocalanus macrurus in relation to environmental variability in the Baltic Sea

2019 ◽  
Vol 76 (7) ◽  
pp. 2427-2436 ◽  
Author(s):  
Heli Einberg ◽  
Riina Klais ◽  
Gunta Rubene ◽  
Georgs Kornilovs ◽  
Ivars Putnis ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Water Temperature ◽  
Environmental Variability ◽  
The Arctic ◽  
The Baltic Sea ◽  
Bottom Water Temperature ◽  
Limnocalanus Macrurus ◽  
The Baltic ◽  
Winter Severity

Abstract The Arctic Limnocalanus macrurus is a prominent representative of large copepods which performs several essential functions in freshwater and marine ecosystems. Being a cold stenotherm species, its distribution is primarily confined to deeper water layers. Based on the long-term observations from one of the largest spatially confined natural populations of this species in the Baltic Sea, we detected profound long-term variability of L. macrurus during 1958–2016: high abundances before the 1980s, then nearly disappearance in the 1990s and recovery in the 2000s. The main environmental parameters explaining the interannual variability of L. macrurus in spring were herring spawning stock biomass in preceding year, winter severity, and bottom water temperature in preceding summer. The effect of winter severity and water temperature was also non-linear. The sliding window correlation analysis pointed to a non-stationary relationship between the abundance of L. macrurus and the key variables. Given the observed pronounced seasonality in the population structure of L. macrurus (young stages dominated in the beginning of the year and only adults were left in the population in summer and autumn) we identified the dynamics of key environmental variables to understand this species under different ecosystem configurations and different combinations of drivers of change.

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