scholarly journals Isotope stratification of meromictic Lake Trekhtzvetnoe at the White Sea coast (Russia)

Author(s):  
Yurij K. Vasil’chuk ◽  
Natalia L. Frolova ◽  
Nikolay S. Kasimov ◽  
Frank Winde ◽  
Nadine A. Budantseva ◽  
...  

Postglacial isostatic uplift of the coastal zone resulted in the formation of isolated lakes along the shores of White Sea developed into permanently stratified (meromictic) lakes. On the basis of monitoring the vertical distribution of selected water quality parameters including temperature, salinity, concentration of major ions, microbial activity, dissolved oxygen and hydrogen sulfide, seasonal changes in the structure of the stratified water column are explored and governing factors identified. Lake Trekhtzvetnoe has a strong vertical stratification with seasonal mixing being confined to the upper part of the water column (mixolimnion). Сhemical water composition in the mixolimnion reflects the influence of precipitation with the underlying chemocline being defined by sharp gradients of salinity, dissolved oxygen and hydrogen sulphide levels. We found strong stable isotope stratification of water column in winter-early spring seasons of 2013, 2015 and 2016 and in the early autumn of 2015. The lowest isotope values were obtained near the surface in the mixolimnion. There was a gradual increase of isotope values towards the chemocline reaching the maximum in the bottom layer (monimolimnion). It was found that water in the mixolimnion was isotopically depleted in winter as a result of ice formation and isotopically enriched in the early autumn due to evaporation. Obvious desalination of mixolimnion and upper chemocline from 2012 to 2016 was possibly caused by the increase of precipitation and freshwater inflow in lake supply. Monimolimnion is a stable layer of high salinity, and it has enriched isotope composition that corresponds with meromictic structure of water column.

1980 ◽  
Vol 31 (5) ◽  
pp. 573 ◽  
Author(s):  
JL Bales ◽  
GK Curtin ◽  
IC Campbell ◽  
BT Hart

The occurrence of algal blooms in Lake Daylesford (area 11.6 ha; maximum depth 9 m) each summer in recent years was investigated. Surface water temperature of the lake varied from 7 to 25�C. The lake which is fed by Wombat Creek, a small permanent stream, was cheimomictic with stratification occurring between summer and early autumn. In most years classical 'turnover' would be unlikely; rather, epilimnetic water would be flushed from the lake by inflowing creek waters approximately 12 times per year. Surface waters were always well oxygenated but the hypolimnion was anoxic between December 1976 and March 1977. Transparency was greatest in winter and early spring and least in summer and early autumn, this reduction being caused by autochthonously produced algal matter and allochthonously derived suspended material. Incommon withmany other Australian lakes, Lake Daylesford had ashallow euphoticzone 1-2 m deep that would limit phytoplankton production. In March and June 1977, over 99% of the incident visible light was absorbed in the top 1 m of the water column. The lake was classified as eutrophic on the basis of chlorophyll a levels. productivity, total phosphorus loadings and algal species. Chlorophyll a levels ranged from < 1 �g 1-1 in June 1977 to 79 �g 1-1 in February 1977; the productivity maximum was 210 mg C m-3 day-1 (560 mg O2, m-3 day-1) in March 1977 and the estimated total phosphorus loading was 2.8 g P m-2 year-1. The algal community was dominated by three genera: the blue-green alga Anabaena, the euglenoid Trachelomonas and the diatom Asterionella. Evidence suggests that reduction of the phosphorus loading to the lake will do much to eliminate the annual algal blooms. Provision of sewerage facilities for the township of Daylesford may achieve the required reduction. The lake sediments contain elevated levels of phosphorus, mainly a result of past discharges of waste material from a potato-processing factory; the contribution of this sediment phosphorus to the water column is unknown but should be investigated.


2015 ◽  
Vol 41 (1) ◽  
pp. 13-19
Author(s):  
Kaniz Fatema ◽  
Wan Maznah Wan Omar ◽  
Mansor Mat Isa

Water quality in three different stations of Merbok estuary was investigated limnologically from October, 2010 to September, 2011. Water temperature, transparency and total suspended solids (TSS) varied from 27.45 - 30.450C, 7.5 - 120 cm and 10 -140 mg/l, respectively. Dissolved Oxygen (DO) concentration ranged from 1.22-10.8 mg/l, while salinity ranged from 3.5-35.00 ppt. pH and conductivity ranged from 6.35 - 8.25 and 40 - 380 ?S/cm, respectively. Kruskal Wallis H test shows that water quality parameters were significantly different among the sampling months and stations (p<0.05). This study revealed that DO, salinity, conductivity and transparency were higher in wet season and TSS was higher in dry season. On the other hand, temperature and pH did not follow any seasonal trends.Bangladesh J. Zool. 41(1): 13-19, 2013


2003 ◽  
Vol 24 (21) ◽  
pp. 4065-4071 ◽  
Author(s):  
D. Pozdnyakov ◽  
L. Pettersson ◽  
O. M. Johannessen ◽  
A. Liaskovski ◽  
N. Filatov ◽  
...  

1997 ◽  
Vol 9 (1) ◽  
pp. 43-45 ◽  
Author(s):  
U. Wand ◽  
G. Schwarz ◽  
E. Brüggemann ◽  
K. Bräuer

Lake Untersee is the largest freshwater lake in the interior of East Antarctica. It is a perennially ice-covered, max. 169 m deep, ultra-oligotrophic lake. In contrast to earlier studies, we found clear evidence for physical and chemical stratification in the summer of 1991–92. However, the stratification was restricted to a trough, c. 500 m wide and up to 105 m deep, in the south-western part of the lake. There, the water body was distinctly stratified as indicated by sharp vertical gradients of temperature, pH, dissolved oxygen, and electrical conductivity. The water column was anoxic below 80 m. The chemical stratification is also indicated by changes of ionic ratios. Moreover, there was some evidence for methanogenesis and bacterial sulphate reduction in Lake Untersee.


2012 ◽  
Vol 90 (8) ◽  
pp. 991-998 ◽  
Author(s):  
C.K. Adams ◽  
D. Saenz

Chinese tallow (Triadica sebifera (L.) Small) is an aggressive invasive tree species that can be abundant in parts of its non-native range. This tree species has the capability of producing monocultures, by outcompeting native trees, which can be in or near wetlands that are utilized by breeding amphibians. Existing research suggests that leaf litter from invasive Chinese tallow reduces survival in larval anurans. The purpose of this study was to determine the effects of Chinese tallow leaf litter on anuran eggs. We exposed eggs of the Southern Leopard Frog ( Lithobates sphenocephalus (Cope, 1886)) at various stages of development to different concentrations of Chinese tallow leaf litter to determine survival. Eggs in the earliest stages of development that we exposed to tallow leaf litter died, regardless of concentration; however, some more-developed eggs exposed to tallow leaf litter did hatch. We determined that the greater the concentration of tallow leaf litter, the lower the dissolved oxygen and pH levels we observed. We suggest that changes in these water-quality parameters are the cause of the observed mortality of anuran eggs in our experiments. Eggs exposed to water containing tallow leaf litter with dissolved oxygen <1.59 mg/L and a pH <5.29 did not survive to hatching.


2021 ◽  
Vol 26 (3) ◽  
pp. 197-206
Author(s):  
Mostafa Imhmed Ighwerb ◽  
Johannes Hutabarat ◽  
Ervia Yudiati ◽  
Rudhi Pribadi

The water quality found on the surface is usually better than that accumulated at the seabed and more bottomless sea. When recycled, water usually brings many materials along the path, all the way to reaching its end. Water quality varies from place to place, season, and different types of rock and soil it passes through also influences the possessed quality. By employing Penaeus merguiensis larvae produced by the Marine Research Center Hatchery owned by Jepara's government, this study analyzes varying effects in three nominal salinities (28, 32, and 36 ppt) and types of diets (Diet A: 100% live feed; Diet B: 100% FRIPPAK; Diet C: a combination of Diet A and Diet C, 50 % each) and finds the optimum water quality parameters such as dissolved oxygen, pH, and temperature on the growth of the newly introduced Penaeus merguiensis larvae. The results show that two nominals of water salinities (28 and 32 ppt) with Diet A works well, supporting the growth from most Zoea to Postlarvae-1: Zoea-1 at 28 ppt with Diet A; Zoea-2 at 32 ppt with Diet A; Zoea-3 at 32 ppt with Diet A; Mysis-1 at 28 ppt with Diet A; Mysis-2 at 28 ppt with Diet C; Mysis-3 at 28 ppt with Diet A; Postlarva-1 at 28 ppt with Diet A. All shrimp prefers temperature ranging from 31-32.4 °C with dissolved oxygen of 4.9-5.74 ppm and pH 7.0-8.1. 


Author(s):  
Vasudha Lingampally ◽  
V.R. Solanki ◽  
D. L. Anuradha ◽  
Sabita Raja

In the present study an attempt has been made to evaluate water quality and related density of Cladocerans for a period of one year, October 2015 to September 2016. Water quality parameters such as temperature, PH, total dissolved solids, dissolved oxygen, biological oxygen demand, total alkalinity, total hardness, chlorides, phosphates, and nitrates are presented here to relate with the abundance of Cladocerans. The Cladoceran abundance reflects the eutrophic nature of the Chakki talab.


2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Lieza Corsita ◽  
Arwin Arwin ◽  
Barti Setiani Muntalif ◽  
Indah Rachmatiah Salami

Physico-chemistry and biological data were investigated  from  October 2010 until April 2011 of Jatiluhur reservoir. A total of six sampling stations were selected for this study. The discharge and hidrological data were obtained from Perum Jasa Tirta II Jatiluhur. The results showed that the hydrological regime in the reservoir Jatiluhur was affected by global phenomenon La Nina events in 2010 and early in 2011. Stream flows were determined during sampling to range from 78  to 482.5 m3/s. The water quality findings were as follows: pH (6.93-8.81), temperature (26.37-30.6°C), dissolved oxygen (0.733-5.2 mg/l), conductivity (2.45-233µmhos/cm), COD (7.36-96.9 mg/l), turbidity (4.063-65.6 NTU), total phosphate (0.002-0.324 mg/l), total nitrogen (0.99-5.96 mg/l), chlorophyl (2.237-43.37 mg/m3), visibility (30-160 cm). The eutrophication was pronounced at Jatiluhur reservoir. Canonical Correspendence Analysis found that some water quality parameters correlated positively with the discharge and the water level.


Author(s):  
Johnathan Daniel Maxey ◽  
Neil David Hartstein ◽  
Dorathy Penjinus ◽  
Alan Kerroux

Stratified estuaries are home to expanding aquaculture activities whose ecological footprints can be observed through trends in microbial community respiration in the water column. Bottle incubations are widely used to measure water column community respiration in marine and freshwater ecosystems by measuring the flux of dissolved oxygen occurring in the bottle over a period of time. When in situ dissolved oxygen (DO) concentrations are markedly different than DO concentration of the incubation medium the potential for diffusion of oxygen across the bottle opening is great and may be especially pronounced in strongly stratified systems with relatively low rates of pelagic oxygen consumption. We incubated 60 Biochemical Oxygen Demand (BOD) bottles filled with sterilized water with DO concentrations ranging from 2.51 mg O2 L-1 to 10.03 mg O2 L-1 for 24 hours in a temperature controlled water bath. There was a significant relationship when DO flux was set as a function of initial DO (DO Flux = -0.0017x + 0.0085, r2 = 0.72, p < 2.2 e-16). DO fluxes ranged from -0.012 mg O2 L-1 hour-1 to 0.005 mg O2 L-1 hour-1 for bottles incubated with initial DO ranging from 10.03 mg O2 L-1 to 3.31 mg O2 L-1, respectively. These results suggest that diffusion across the ground glass seal of BOD bottles is possible and that extra precaution through parallel diffusion controls should be considered when measuring pelagic respiration using BOD bottle incubations in systems with relatively low or relatively high in situ DO concentrations.


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