Inland Saline Groundwater Research Articles

Study on Environmental Materials with Analysis of the Characteristics and Formation Mechanism of Inland Saline Water in the Northwest of Shandong

Study on characteristics and formation mechanism of inland saline water is conducive to develop and utilizing saline water resources scientifically and reasonably. Taking alluvial plain of the Yellow River in the Northwest of Shandong as an example, based on experimental data, chemical composition and spatiotemporal variation characteristics of inland saline groundwater are discussed and its formation mechanism is revealed. Result shows old interchannel belt, sullen water flow, high evaporation and different hydro-geochemistry functions are formation conditions of high salinity saline water in inland area. From the mainstream of old channel to saline water area of interchannel belt, groundwater hydro-chemistry type by HCO3- evolves into the Cl.SO4 -Mg.Na.Ca type and Cl.SO4-Na.Mg.Ca type gradually.Thus, improving measures such as pumping saline water in non-flood season and treating water with reverse osmosis material and so on are put forward to make the saline water evolve into fresh water.

Aquaculture of Marine Fish in Inland Low Salinity Well Water: Potassium Is Not the Only Limiting Element

Inland saline groundwater is abundant in various areas of the world but is not suitable for traditional agriculture irrigation and is also not suitable for marine aquaculture mainly because of potassium deficiencies. In the present work, we used marbled spinefoot rabbitfish Siganus rivulatus, as a model organism to investigate whether varying levels of aqueous K+ affect survival and growth, and whether ambient K+ has an effect on fish osmoregulation and haemolymph osmolality. A ten-week growth experiment was conducted where fish were reared in reconstituted inland saline water containing K+ concentrations equivalent to 15%, 40% and 100% (denoted as: Trt15, Trt40, and Trt100, respectively) of potassium in 15 ppt seawater. A 15 ppt seawater treatment (CSW) was used as a control. Fish weight, length, survival, Fulton-type condition index, blood and water osmolality, and serum Na+ and K+ concentrations were evaluated. Gill NKA activity was also estimated. Fish reared in Trt15 died during week 8. At the end of the experiment (week 10), no differences were observed in fish survival and total length among treatments Trt40 and Trt100 and control (P>0.05). Final weight was less in Trt40 and Trt100 than in CSW. Fulton-type condition index results showed that Trt100 was more suitable for fish than Trt40, but still not as suitable as 15 ppt sea water. Sodium (Na+) in serum was not affected by aqueous K+ levels, whereas serum K+ varied congruently with aqueous K+. Rabbitfish reared in Trt40 and Trt100 had greater blood osmolality than those reared in control seawater. Gill NKA activity also increased by 50% in Trt40 and Trt100 as compared to control. The present study shows that potassium-deficient 15 ppt inland well water is not suitable for long-term culture of Siganus rivulatus. Results suggest that inland saline well waters greatly increase activity of NKA and consequently energy expenditure. Furthermore, K+ does not appear to be the only limiting mineral in inland low salinity groundwater that affects fish osmoregulation.

Investigation Into the Suitability of Inland Ground Saline Water for the Growth of Marine Microalgae for Industrial Purposes

An increasing shortage of crude oil has necessitated into alternative energy sources. In Australia, inappropriate agricultural practices have left large areas of agricultural land subject to secondary salinisation from rising water tables. Opportunities have arisen from groundwater interception schemes for the aquacultural production of marine microalgae far inland from coastal areas where a shortage of suitable sites and strict environmental regulations makes the production of large volumes of microalgae unrealistic. Four small-scale laboratory experiments were undertaken to determine the potential growth of the two species of marine microalgae, Isochrysis galbana Parke and Tetraselmis suecica Stein, in inland saline ground water sourced from a ground water monitoring bore in rural Victoria. The results showed that at the termination of the experiments the differences between experimental units and control treatments of I. galbana and T. suecica with and without algal growth nutrient were not significantly different.

The effect of salinity on the requirement for potassium by barramundi ( Lates calcarifer) in saline groundwater

Significant international interest exists in utilising inland saline groundwater sources for mariculture; however potassium deficiency is a factor that may limit their use. In this study we investigated the effects of potassium supplementation between 25% and 100% of that found in equivalent salinity seawater on the growth, survival and physiological response of barramundi ( Lates calcarifer) at hyperosmotic (45 ppt), near-isosmotic (15 ppt) and hyposmotic (5 ppt) salinities. A K-equivalence of 25% was not tested at 45 ppt because it caused mortality of barramundi in a previous study. Fish reared in 50% K-equivalence water at this salinity survived for four weeks but lost weight; whereas at 75% and 100% K-equivalences fish both survived and gained weight. Homeostasis of blood plasma potassium in these fish was maintained by buffering from skeletal muscle. That these fish exhibited muscle dehydration, increased branchial, renal and intestinal (Na +–K +)ATPase activity and elevated blood sodium and chloride suggests they were experiencing osmotic stress. At 15 ppt, equal rates of growth were obtained between all K-equivalence treatments. Buffering of plasma potassium by muscle also occurred at the two lowest levels of supplementation but appeared to be in a state of equilibrium. Barramundi at 5 ppt displayed equal growth among treatments. At this salinity, buffering of plasma potassium from muscle did not occur and at 25% K-equivalence blood potassium was significantly lower than at all other K-equivalence treatments but with no apparent effect on growth, survival or (Na +–K +)ATPase activities. These data show that proportionally more potassium is required at hyperosmotic salinities compared to iso- and hypo-osmotic salinities and also demonstrate that barramundi have a lower requirement for potassium than other species investigated for culture in inland saline groundwater.

Effect of Periphyton and Supplementary Feeding on Growth Performance and Nutritive Physiology of Nile Tilapia, Oreochromis niloticus, and Pearlspot, Etroplus suratensis, Under Polyculture

ABSTRACT Growth performance of Nile tilapia, Oreochromis niloticus, and pearlspot, Etroplus suratensis, under polyculture was studied in inland saline groundwater ponds. Three treatments (1–3) each in replicate of two were maintained: In Treatment 1 (substrate ponds), bamboo poles as additional substrate were provided for the development of periphyton, while in Treatment 2 (fed ponds), no additional substrate was provided; however, the fish were fed on supplementary diet (40% CP). Treatment 3 served as control, where neither the fish were fed on any supplementary diet, nor any substrate provided in the ponds. Irrespective of the treatment (duration 90 days), ponds were fertilized with cow-dung at 7,500 kg/ha/year. Results revealed significantly (P < 0.05) higher fish growth in Treatment 1 due to the provision of additional substrate compared with diet (39%) and control (102%) ponds. The exponential value of “n” for both the fish species was higher (n = 3.2) in ponds provided with additional substrate than fish fed a diet or fish in control ponds. Further, irrespective of treatment, growth performance of O. niloticus was significantly (P < 0.05) higher than E. suratensis. Significant differences in most of the water quality parameters were not observed among the three treatments; however, bicarbonate, pH, electrical conductivity, NH4-N, NO2-N, and o-PO4 were significantly (P < 0.05) lower, while NO3-N remained significantly (P < 0.05) higher in ponds having substrate (Treatment 1). Further, a review of data indicates that some of the productivity indicating parameters (viz, TDS, turbidity, and alkalinity), and BOD5 were significantly (P < 0.05) higher in Treatment 2 compared with Treatment 1 and control ponds. Net primary productivity (NPP), chlorophyll a, and sulphate concentration remained significantly lower (P < 0.05) in ponds with substrate (Treatment 1). No significant variations in carbonate concentration, gross primary productivity (GPP), plankton density, and plankton species diversity were observed among the three treatments. Significantly (P < 0.05) high periphyton biomass in terms of dry matter (1.6 ± 0.03 mg/m2), chlorophyll a (10.3 ± 0.69 μg/cm2), pheophytin a (3.5 ± 0.36 μg/cm2), and mean periphyton productivity (0.9 mg C/m2/day) were observed at a depth of 50 cm in ponds with substrate (Treatment 1). On the other hand, autotrophic index (AI) remained low at 50 cm depth. Epilithic periphyton density and chlorophyll a concentration in substrate ponds were significantly (P < 0.05) lower compared with the other two treatments. No significant variation in sediment quality among different treatments were observed; however, NO3-N and benthos were significantly (P < 0.05) higher in diet and control ponds compared with substrate ponds. Significantly (P < 0.05) higher values of digestive enzyme activity (protease, amylase, and cellulase), accumulation of high muscle protein, muscle, and liver glycogen, and also higher values of viscero-somatic index (VSI) and hepato-somatic index (HSI) were observed in fishes grown in ponds with substrate compared with other treatments. Proximate composition of periphyton indicates high protein (35.0–41.1%) and energy contents (13.3–15.5). These investigations suggest that provision of additional substrate for the enhancement of periphyton production has a greater importance in growth enhancement of Nile tilapia and pearlspot when stocked at the densities used in this study (10,000 fish/ha).

Survival and Growth of Silver Perch, Bidyanus bidyanus, a Salt‐tolerant Freshwater Species, in Inland Saline Groundwater from Southwestern New South Wales, Australia

Survival and Growth of Silver Perch, <i>Bidyanus bidyanus</i>, a Salt‐tolerant Freshwater Species, in Inland Saline Groundwater from Southwestern New South Wales, Australia

Effect of varying dietary protein levels on growth and production of Chanos chanos (Forsskal) in inland saline groundwater: laboratory and field studies

Two experiments were conducted to investigate the effects of varying dietary protein (35–45%) and energy levels (17.34–19.44 kJ g−1) on the growth performance of milkfish (Chanos chanos) maintained under laboratory (experiment 1) and field conditions (Experiment 2) in inland saline groundwater. The results of experiment 1 (initial weight of fish: 0.25 g) revealed that, irrespective of the protein source (fish meal or processed full fat soybean), fish fed a diet containing 40% protein showed significantly (p<0.05) higher growth in terms of live weight gain and specific growth rate, low feed conversion ratio [1.71 (fish meal) and 1.58 (soybean)], high nutrient retention (gross protein retention: 28.59 and 31.05%; gross energy retention: 24.23 and 26.04%), apparent protein digestibility (81.74 and 85.91%) and digestive enzyme activity (specific protease and amylase). An observation on the postprandial excretion of metabolites (N–NH4 and o–PO4) indicated significantly (p<0.05) low levels of these metabolites in aquaria where the fish were fed 40% dietary protein irrespective of the protein source. The results of experiment 2 also indicate (initial weight of fish: 4.43 g) a significantly (p<0.05) higher growth performance (weight gain, biomass, specific growth rate, growth day−1 and fish production) in ponds where the fish were fed 40% dietary protein. Irrespective of the experimental conditions (laboratory/field), feeding the fish higher dietary protein levels (beyond 40%) not only repressed growth performance but also affected proximate composition by lowering protein accumulation and energy assimilation. An investigation on the effects of feeds on water quality parameters revealed that values for total alkalinity, NH4–N, NO3–N, turbidity, total dissolved solids and parameters indicative of productivity (chlorophyll a, net primary productivity and plankton population) increased significantly (p<0.05) from treatments 1–3 (35–40% protein) and declined thereafter, in treatment 4 (42% dietary protein), indicating that water quality characteristics correlated well with fish growth. The results suggest that in order to obtain a high-yield in milkfish culture system the fish should be fed supplementary diets containing appropriate (40%) protein levels, especially when the stocking rates are high.

Combined effects of salinity and potassium concentration on juvenile mulloway (Argyrosomus japonicus, Temminck and Schlegel) in inland saline groundwater

This paper reports on experiments conducted to examine the combined effects of salinity and potassium concentration on survival and growth of juvenile mulloway (Argyrosomus japonicus, Temminck and Schlegel) in inland saline groundwater. Three separate experiments were conducted in 20 (±1)°C water. In the first experiment, mulloway were held in 60 L aquaria (triplicate) with salinities of 5, 15, 25 or 35 g L−1 and potassium concentrations of 20%, 40%, 60% or 80% of the concentration present in oceanic water of the equivalent salinity in a 4 × 4 factorial combination for 7 days. Response surface contour diagrams were generated from survival data to estimate optimal conditions. The results showed that maximum survival of juvenile mulloway occurred at salinities of >14 g L−1 and potassium concentrations of >38%. Survival was lowest at salinities of <7 and >33 g L−1 and potassium concentrations of <25%. The second experiment was conducted with mulloway held in 60 L aquaria at salinities of 15, 25 or 35 g L−1 and potassium concentrations of 40%, 60%, 80% or 100% in a 3 × 4 factorial combination for 44 days. Optimal conditions for maximum survival and growth of mulloway were within a salinity range of 15–35 g L−1 and potassium concentration above 40%. The third experiment was conducted in three 500 L tanks to record the survival and growth of mulloway fingerlings held at 20 (±1)°C, 23 g L−1 salinity and potassium concentrations of 50% for 8 months. Survival and growth of mulloway fingerling in inland saline groundwater were similar to those reported from a semi-intensive floating tank system in inland saline water and sea cage trials in oceanic water.

Determination of Fertilization Rate for Optimum Pond Productivity and Fish Growth in Inland Saline Groundwater Ponds: Monoculture of Grey Mullet and Milkfish

The effects of four rates of application of organic fertilizer (cow-dung) along with supplementary feed- ing were studied on water quality and pond productivity in terms of plankton production and fish biomass in inland saline groundwater ponds. Two experiments were conducted. In experiment 1, ponds were fertilized (at 5000, 7500, 10000 and 12500 kgha -1 •y -1 ) and stocked (at 6000 ha -1 ) with Mugil cephalus, while in experiment II, Chanos chanos was stocked (at 6000 ha -1 ) and ponds were fertilized at 2500, 5000, 7500 and 10000 kgha-1•y -1 . The growout period for both the experiments was 100 days. Irrespective of the species stocked, significantly (P<0.05) high growth performance of grey mullet and milkfish in terms of biomass and mean fish weight gain were observed in ponds fertilized at 7500 kgha -1 •y -1 of cow-dung. Significantly (P<0.05) high values of parameters indicative of productivity (viz. turbidity, alkalinity, net primary productivity-NPP, Chloro- phyll a concentration and plankton population) also coincided with the high fish growth. Nutrient release (o-PO4, NO3-N and total kjeldahl nitrogen) also remained significantly (P<0.05) high in ponds fertilized at 7500 kgha -1 •y -1 . At higher or lower rates of fertilization, the values of most of these parameters remained low. Application of stepwise multiple regression models showed a significant and positive correlation of nutrients, NPP and plankton population with fish growth. Statistically also fish weight gain showed a significant positive correlation with nutrients (viz. NO3-N (r=0.66, P<0.001; r=0.36, P<0.05), o-PO4 (r=0.70, P<0.001; r=0.27, P<0.05), alkalinity (r=0.45, P<0.001; r=0.50; P<0.001) and Kjeldahl-N (r=0.37, P<0.05; r=0.45, P<0.001)), net primary productivity (r=0.56, P<0.001, r=0.49, P<0.001) and plankton density (r=0.51, P<0.001; r=0.73, P<0.001) in both the experiments, respectively. A decline in fish biomass and pond productivity at higher rates of fertilization (10000 or 12500 kgha -1 •y -1 ) has been attributed to high NH4-N and BOD5 levels. Further, based on estimated production function relating pond productivity (fish production, dissolved oxygen concentration and net primary productivity) to fertilizer loading rate (dosages of cow-dung), optimum fertilizer loading rates were computed and found to be 7500 kgha -1 •y -1 . Therefore, a dosage of 7500 kgha -1 •y -1 of cow-dung along with supplementary feeding appears to be optimum for obtaining high productivity in inland saline water ponds with salinity levels ranging between 13.0-21.0 ppt.

Use of Additional Substrate to Enhance Growth Performance of Milkfish, Chanos chanos (Forsskal) in Inland Saline Groundwater Ponds

Milkfish, Chanos chanosfingerlings were cultured in inland saline groundwater ponds. Bamboo poles as additional substrate were used to increase the surface area of the ponds (Treated ponds). Controls, without the provision of additional substrate, were also maintained. After a culture period of 60 days, significantly (P < 0.05) higher growth was observed in treated ponds (mean fish wt. 86.6±2.4 g; SGR 1.5±0.01) as compared to controls (mean fish wt. 50.2±1.2 g; SGR 1.0±0.1). Length-weight relationship showed high exponential value (n) of length in treated ponds (n = 2.49) in comparison with controls (n = 1.63). Significant differences in most of the water quality parameters were not observed between the two treatments; however, turbidity, NH4-N, net primary productivity, chlorophyll apheophytin aand zooplankton population were significantly (P < 0.05) higher in controls. Significantly, (P < 0.05) high periphyton biomass in terms of dry matter (DM) (1.5±0.02 mg/cm2), chlorophyll a (13.5±1.1 μg/cm2), pheophytin a (8.3±1.2 μg/cm2) and mean periphyton productivity (1.4 mg C/m2/day) were observed at a depth of 50 cm in treated ponds. Autotrophic index was significantly (P < 0.05) low at 50 cm depth than at the other depths. Low values of epilithic periphyton density in ponds provided with additional substrate indicate the incorporation of planktonic flora and fauna in periphyton development. These investigations thus clearly suggest that the provision of additional substrate in culture ponds resulted in higher yield of milkfish.

Ionic manipulation of inland saline groundwater for enhancing survival and growth of Penaeus monodon (Fabricius)

A series of four trials were conducted on inland saline groundwater of 58 g L−1 diluted to lower salinities up to 10 g L−1 and later manipulating its ionic concentrations to enhance the survival and growth of Penaeus monodon postlarvae (PL). In the first experiment, the survival of PL was tested at several salinities (10, 20, 30, 40, 50 and 58 g L−1), and the survival of PL was studied in comparison with natural sea water of similar salinities. Complete mortality of PL was observed at all salinity levels within 144 h. Longest survival for 96 h followed by 72 h was found at 10 and 20 g L−1 salinity respectively. In the second experiment, survival of PL was tested at 10–20 g L−1 salinity at different concentrations of calcium varying between 100 and 300 mg L−1. The survival of PL could be increased to 7 days at 12.5 g L−1 salinity by reducing the calcium level to 200 from 921.8 mg L−1 with magnesium and potassium levels of 208.5 and 30.03 mg L−1 respectively. In the third experiment, the survival of PL could be further enhanced to 18 days at the same salinity by increasing the magnesium level from 208.5 to 400 mg L−1 with potassium held at 30.03 mg L−1. Survival and growth of PL in inland saline water of 12.5 g L−1 salinity similar to performance in sea water of the same salinity was achieved by increasing the potassium concentration from 30.03 to 200 mg L−1 with calcium and magnesium levels of 199.5 and 199.4 mg L−1 respectively.

Effect of periphyton on growth performance of grey mullet, Mugil cephalus (Linn.), in inland saline groundwater ponds

Summary The present study attempts to assess the potential of artificial substrates to enhance fish production in inland saline groundwater ponds through periphyton production. Grey mullet, Mugil cephalus, was cultured for 100 days in ponds with substrate (treatment ponds) and without substrate (control ponds). To enhance the surface area, bamboo poles were used as substrate. The periphyton population, pigment concentration and hydrobiological characteristics of pond water were monitored. The studies revealed little difference in most of the water quality parameters observed in the two treatments. However, turbidity (27.0 ± 0.1–35.0 ± 0.1 Nephalo Turbidity Unit (NTU)), chlorophyll ‘a’ (6.6 ± 0.6–7.6 ± 0.6 μg L−1), plankton population (phytoplankton 8.4 × 103–9.4 ×103 numbers L−1; zooplankton 4.0 × 103–5.1 × 103 numbers L−1) and NH4–N (2.0 ± 0.2–2.3 ± 0.1 mg L−1) were high in the treatment with no additional substrate; however, in the treatment with substrate the total Kjeldahl nitrogen (9.8 ± 0.8–10.8 ± 0.7 mg L−1) and o-PO4 (0.1 ± 0.01–0.1 mg L−1) remained significantly (P < 0.05) higher. Highest periphyton biomass in terms of dry matter (DM) (0.8 ± 0.01–1.4 ±0.01 mg cm−2), ash free DM (0.4 ± 0.0–0.6 ± 0.01 mg cm−2), chlorophyll ‘a’ (3.1 ± 0.2–8.1 ± 0.8 μg cm−2) and pheophytin ‘a’ (1.9 ± 0.4–3.9 ± 0.5 μg cm−2) was observed at 50 cm depth in ponds provided with additional substrate. Fifteen plankton genera showing periphytic affinity colonized the bamboo substrates. Fish growth (mean fish weight 524.3 ± 8.7 g and SGR 2.5 ± 0.1) was significantly (P < 0.05) higher in ponds provided with additional substrate compared with control ponds (387.2 ± 6.0). Length–weight relationship (LWR) (W = cLn) also showed that the exponential value (‘n’) of length was high in substrate-supported ponds (n = 2.36) in comparison with controls (n = 1.09). These studies suggest that a periphyton-supported aquaculture system can be used successfully for the culture of herbivorous brackishwater fish species like M. cephalus in inland saline groundwaters and thus could contribute to the development of sound and sustainable aquaculture technology.

Comparative Evaluation of Dietary Protein Source And Level on Growth Performance and Nutrient Retention In &lt;i&gt;Mugil cephalus&lt;/i&gt; (Linn.) Fry

Ten diets (1-10) with varying protein levels (35, 38, 40, 42 and 45%) were formulated using processed full fat soybean (diet 1-5) and fish meal (diets 6-10) as the major protein sources. Mugil cephalus fry (mean body weight 0.5±0.01 g) were maintained in glass aquaria in inland saline groundwater (15 %o) under laboratory conditions (LD 12:12 at 20±1°C) and fed twice daily for 70 days at 5% body weight on one of the ten experimental diets. Studies have revealed that growth performance (in terms of live weight gain, SGR and growth per cent gain), nutrient retention (PER, GPR and APD), accumulation of carcass protein and fat were significantly (p &lt; 0.05) high in the groups fed on diet containing 40% protein, irrespective of source, however, the values were high for the diet containing processed full fat soybean as the protein source. Further, the fry fed on soybean containing diet (at 40%) had high feed conversion efficiency and apparent protein digestibility (82.7%) and also excreted significantly low (p &lt; 0.05) ammonia (N-NH4) and reactive phosphate (0-PO4) in the holding water in comparison with the fry fed on fish meal containing diets. From these studies, thus, it is evident that supplementary diet with 40% protein and 9.1% fat, 18.5 k]/g gross energy and a P/E ratio of 109.0 mg/KCal of metabolized energy appears to be optimal for maximising the growth of M. ceplwlus when grown in inland saline groundwater.

Survival and growth of Australian snapper, Pagrus auratus, in saline groundwater from inland New South Wales, Australia

Australia has extensive resources of inland saline groundwater, which may be suitable for culture of marine fish. This study assessed the suitability of saline groundwater, which was pumped from a shallow aquifer into an evaporation pond near Wakool in western New South Wales, for growth and survival of juvenile snapper, Pagrus auratus. Five experiments were conducted. The first showed that snapper (31 g) did not commence feeding, lost equilibrium of buoyancy and became moribund within 3 days after transfer from coastal seawater (diluted to 19‰ with rainwater) to saline groundwater (19‰). Potassium concentration of diluted coastal seawater and groundwater (both 19.6‰) was 203 and 9.2 mg l −1, respectively, while the concentration of most other major ions was similar in water from both sources. In the second experiment, groundwater of 21‰ salinity was fortified with potassium (as KCl) to provide 25%, 50% or 100% of the concentration of potassium found in coastal seawater of 21‰ salinity. Survival and feeding and swimming behaviour of snapper (1.5 g) held in tanks for 8 days were the same in 50% and 100% potassium-fortified treatments as in coastal seawater controls. However, snapper held in groundwater fortified with only 25% potassium, or raw saline groundwater became moribund after 4 and 2 days, respectively. During the third 42-day experiment, growth, survival and food conversion of juvenile snapper (4.0 g) were the same in diluted coastal seawater (20‰) and groundwater (20‰) provided the level of potassium in the groundwater was increased to within 60–100% of the concentration in coastal seawater. During the fourth experiment, juvenile snapper were acclimatised to raw saline groundwater by transferring fish from fortified groundwater with initial potassium levels of 100% of that in coastal seawater, to groundwater with 10% lower potassium levels every 3.5 days or 20% lower levels every 7 days. A further treatment where snapper were transferred from groundwater fortified initially with potassium levels of 60% of coastal seawater, to groundwater with 20% lower potassium levels every 3.5 days was included. When potassium was reduced to 20% of the concentration in coastal seawater, in all treatments, fish became moribund. Results from the fifth experiment, where groundwater was fortified with either KCl or NaCl at equivalent chloride levels, confirmed that potassium and not chloride ions were responsible for improvement in groundwater. Our results demonstrate that saline groundwater from Wakool, fortified with KCl is a suitable medium for growing snapper juveniles in tanks.